Monday, April 18, 2011

Space Warfare XV: Further Reflections on Laserstars


Much of the comment thread on Part XIII of this series, The Human Factor, turned into a discussion of 'laserstars.' While a thread of 631 comments (so far) might seem to have given this particular debate the full Rasputin treatment, I am instead going to use it as a pretext for another front page post. (And an arguably wretched pun in the title.)

Laserstars, as the term has come to be used on this blog, are military spacecraft designed to carry and deploy a single powerful weapon laser installation of the maximum practical aperture and power. In their 'ideal' form they would be drones, robotic in the broad sense that includes remote control from a separate command ship (or ground station, etc.).

A couple of provisos are needed. In conceptualizing laserstars I chiefly have in mind classical-style lasers operating broadly in the optical band (IR through UV), whose beams are passed through telescope-style aiming and focusing optics. It is this telescope, more than the individual laser itself, that provides the distinctive feature of a 'laser cannon' - if the available power is more than a single laser can handle you could easily have an entire bank of lasers all firing through the same optical system.

If you have lasers zapping in the far UV or X-ray bands, the aiming optics become quite different. My impression is that the main telescope becomes long and narrow instead of short and wide. In either case, however, the optical system of a laserstar is implicitly too big, relative to the whole spacecraft, to be mounted in some equivalent of a turret. Instead it is 'keel-mounted,' and gross aim is achieved by pointing the entire spacecraft toward the target.

The general argument for all this is that the effective range of a laser is in linear proportion to the aperture of its optical system. Double the telescope aperture and you double the range at which the system can achieve a given spot size and zap intensity.

But a further proviso is that the largest practical laser installation and optical system are in fact large enough that you can only conveniently mount one aboard a spacecraft that is itself of practical size for war service. If it turned out that the most cost-effective size for the spacecraft, with its drive engine and power supply, could carry half a dozen of the 'largest practical' laser optical installations, that is how many it would carry.

Finally, a broader proviso is that a laserstar is not to be regarded as a 'space warship.' It is perhaps more nearly analogous to a railroad gun, deployed to a position where it can make use of its long range firepower while being supported by other spacecraft. In spite of the image at the top of this post, I don't see laserstars primarily engaging in combat in low orbit around a planet, but rather at the outer edge of a planet's strategic envelope, either defending it against attack from elsewhere or maintaining a blocked by cutting off communications with or relief from elsewhere.

In the comment thread previously linked, commenter Tony raised several serious issues with respect to the laserstar concept. These range from the technical to the meta, and I'll discuss what I see as the most critical objections in that order. (The expressions of these issues, however, are mine, not Tony's.)


Precision and the battlefield don't mix.
There is a lot of precedent for the general observation that pinpoint accuracy is hard to achieve amid the turmoil of combat. On the other hand, in the contemporary era precision-guided munitions have demonstrated capabilities that would have startled military observers of an earlier era. And laserstars are not a rock & roll weapon, which is why I wouldn't expect to see them in action in (relatively!) crowded planetary space. They are long range artillery for use against targets that must travel through deep space.

Monocultures are vulnerable.
This principle of ecology also applies to warfare: Dependence on one weapon generally makes you vulnerable to an enemy who can make use of several. A laserstar by itself is indeed dangerously inflexible. In its 'pure' form it would be deployed only in a constellation containing other spacecraft and weapon systems.

In other situations I would expect to see only partial application of the laserstar concept - for example, I suspect that multi-mission military spacecraft (broadly 'cruisers') would carry a single big keel-mounted laser mirror, for long range zapping power, while also carrying a few smaller mirrors, along with kinetics, for fighting in more chaotic environments.

And, of course, having said this, in any given setting it is plausible that things have worked out otherwise. Laserstars or their like may have no place in the order of battle, for perfectly credible reasons ranging from inability to combine extreme steadiness with extreme power levels, to a power-political environment in which the ability to zap things at 30,000 km has no military significance.

Space armadas have no place in the plausible midfuture anyway.
On this point I plead guilty; significant military operations beyond Earth orbital space are an inherently operatic concept, only to be expected when there are substantial human populations, strategic assets, and even polities scattered across space.

This point has a couple of sub-implications. Since we are somewhere beyond the plausible midfuture anyway, techlevels are presumably higher, especially propulsion performance and thus the ability to sling kinetics.

A subtler argument also stems from being beyond the 'plausible midfuture:' A civilization with colonies and space armadas has evidently solved the problem of sending large numbers of people into space - weakening the argument for automated spacecraft as against human crews.

The specific response to these points would be that higher techlevels presumably apply as well to lasers and automation. But really this aspect of the debate takes us into an issue broader than just laserstars, namely the balance of technology and the flavor of technology in space-operatic settings.

I used to have an SF paperback that featured, among other things, a reconditioned World War II heavy cruiser armed with smoothbore muzzle-loaders. This combination was justified by a post-apocalyptic setting, but in general we want our future technologies to have an internally consistent techlevel, or at any rate feel as if they do. What constitutes this internal balance is itself, of course, a matter of speculation.

Also, if you are a regular reader of this blog you probably have a bias toward 'realistic' space technology, in a sense that is as much aesthetic as strictly technical. Roughly, you want spaceships that are broadly recognizable as industrial products - at least descended from the plausible midfuture, even if that era has become the plausible mid-past.

I will deal further with this subject (but not necessarily laserstars) in upcoming posts.

Meanwhile, discuss.



Via Atomic Rockets, this Martin-Marietta concept for an orbital laser ABM platform gives the general impression of a laserstar, but is already notably retro - probably of 1980s vintage. We'll delicately ignore the visible-in-space beam.

410 comments:

1 – 200 of 410   Newer›   Newest»
Milo said...

Rick:

"If it turned out that the most cost-effective size for the spacecraft, with its drive engine and power supply, could carry half a dozen of the 'largest practical' laser optical installations, that is how many it would carry."

So what is the largest practical laser?

Things limiting the size of cannons on ships-of-the-line include:
- The wooden hull mountings could only handle so much recoil before splintering.
- The cannons had to be loaded by hand, and there is a limit to how large a cannonball a human (or even a team of humans) can carry.
- The cannons also had to be aimed by hand, so again, there is a limit to how heavy you could reasonably make them while still being able to point them in the right direction.
None of these are obviously an issue for lasers. However, it may be that waste heat will be easier to deal with if you spread it around the ship.


"Finally, a broader proviso is that a laserstar is not to be regarded as a 'space warship'. It is perhaps more nearly analogous to a railroad gun,"

I'm not particularly familiar with railway gun deployment tactics, but they weren't primarily used against other rail vehicles, were they?

KraKon said...

Okey dokey:

"My impression is that the main telescope becomes long and narrow instead of short and wide."

UV is a bit hard here. A simple fresnel lens could suffice, while more x-rayish metal deflectors are required at shorter wavelengths.

"My impression is that the main telescope becomes long and narrow instead of short and wide. In either case, however, the optical system of a laserstar is implicitly too big, relative to the whole spacecraft, to be mounted in some equivalent of a turret. "

The main telescope, if it is mainly a long accelerator, can be made to be short and fat. The accelerator is divided into, say, 6 seperate tubes, with the beam of electrons going back and forth between them.
Turrets are aweful for targeting accuracy, since the vibrations of the turret motors, as well as the counterrotation from the ship, make it jumpy at best. Turrets are not however out of the question, as you could easily design a ship with the mirror being placed onto a rotating mount, and the beam being bounced off of it from behind. It has the advantage of being able to swivel quickly, and shoot backwards (nearly, there's still the ship's shadow). Shooting straight forward is still a problem as I was told that beam divergence is propotional to the aspect of the lens being shown to the target, and at low angles, this suffers.

"But a further proviso is that the largest practical laser installation and optical system are in fact large enough that you can only conveniently mount one aboard a spacecraft that is itself of practical size for war service."

As we have learnt over the course of our speculation, every factor is linked in warship design. The power generator gives you X watts to play around with. The laser generator's power density gives you the mass of the laser required to fully utilize that power. The mass of the laser takes up most of your payload, so it defines how powerful a drive you need. That drive power in return defines how much power you can generate. You can loop around forever until you hit heating problems.

KraKon said...

As for dozens of lasers, it is going to be unlikely. They can be joined into a single beam for a more effective single laser, or just simply replaced with one big laser. From what I understood, installing a secondary mirror to split the beam is cheaper and lighter than adding a second small laser generator.

"I don't see laserstars primarily engaging in combat in low orbit around a planet, but rather at the outer edge of a planet's strategic envelope, either defending it against attack from elsewhere or maintaining a blocked by cutting off communications with or relief from elsewhere."

I see them being IN low orbit, targeting hostiles OUTSIDE low orbit. Low orbit laser installation means it can be repaired easily, and put into place for less effort and cost. Long range means it can still engage far away targets. The laser's effective range will then define the planet's strategic envelope. Closer in stuff will be fried. Further out, and you'll have to start moving things.

"here is a lot of precedent for the general observation that pinpoint accuracy is hard to achieve amid the turmoil of combat. "

I fully agree with this, and even applying current tech trend speculation leads to worrying results.
A milliarcsecond is considered military grade precision, but a regular 30cm wide missile can only be targeted from 340km out. If it is moving at 30km/s, you have a bit more than 10s to take it out.
Using the speculative to capabilities of adaptive optics telescopes ie 50microarcseconds, the same kinetics can only be targeted from 1200km out. That still leaves us with only 40s to take it out, or around 10 times less than what we have been considering until now. As the battle drags on, it becomes more and more unlikely that you can find and zap incoming waves before they obliterate you.

KraKon said...

"in its 'pure' form it would be deployed only in a constellation containing other spacecraft and weapon systems."

Laserstars are not a monoculture, just as battleships, destroyers, cruisers, gunboats are not monocultures. They all use the same weapons system (a laser, a gun) but in so many ways and with so many variables that it easily distinguishes them as different weapon systems with different purposes and different vulnerabilities.
For example, we could have, within the same task force a very long range X-ray laserstar, a medium range UV laserstar, and a short range visual laserstar. The X-ray laserstar engages in flashlight and damage over time tactics from far far away; sacrificing armor and maneouverability for maximal range and beam power.

The medium range UV laserstar, instead of taking out the enemy like a sniper, closes the distance. It moves towards the enemy, giving its more efficient but lower range laser the ability to zap stuff. It can follow targets around, and can be used en masse to take out enemy xraserstars. Our cavalry.

The short range visual laser is very short range, but its job is to take out kinetics that have gone through the previous defensive nets. This amounts mainly to swarms of shrapnel, or brilliant pebbles, or anything. This laserstar has a single central laser, but a beam redirector splits its power among tens of mirrors. Each can engage projectiles rapidly, giving this defensive-role laserstar the ability to take out a large number of kinetics during the short time available to it.

Of course, we'll add kinetics crafts to the constellation, but they can be no more than dumb drones and missile busses.

KraKon said...

"Since we are somewhere beyond the plausible midfuture anyway, techlevels are presumably higher, especially propulsion performance and thus the ability to sling kinetics."

I guessed that :)
What are the new performance levels? Do we have access to ICF or do we just have bigger nuclear-electric VASMIR drives? Thsi defines the power levels we can generate, therefore the laser's effective ranges.

"weakening the argument for automated spacecraft as against human crews.'

While current trends are showing that automated spacecraft are going to get exponentially better while humies...stay the same, so are just as hard to move around. Since drive performances go up in steps rather than jumps (and drive performance defines how easily we more mass, therefore humans around), while automation technology can leap forward, I'd still see advanced automation as having a place in a constellation.

"I used to have an SF paperback that featured, among other things, a reconditioned World War II heavy cruiser armed with smoothbore muzzle-loaders. "

Schizotech!

PS:Thanks for rapid-firing 3 space warfare posts! Just waiting for the nuclear pulse propulsion one...

Tony said...

KraKon:

"Laserstars are not a monoculture, just as battleships, destroyers, cruisers, gunboats are not monocultures. They all use the same weapons system (a laser, a gun) but in so many ways and with so many variables that it easily distinguishes them as different weapon systems with different purposes and different vulnerabilities."

The battleship per se was not a monoculture, but the rifled gun was a monoculture. The gun was eventually optimized for several different roles, but it was never enough, on its own, to dominate all modes of naval warfare. Torpedo craft had to be resisted by destroyers and cruisers; secondary batteries wwren't enough. Strike aircraft had to be countered by fighters; AA guns weren't enough.

Now, in space, it is true that everyone is fighting in a homogenous medium (leaving proximity to gravity sources aside). But there will be, for example, kinetics that may be best countered by finding ways to take out their launchers before they launch, rather than shot down on incoming trajectories. Food for thought.

Tony said...

Re: laserstars and railroad guns

I'm not at all sure about this analogy. Rail guns were only rail guns because railroads were the only way to move guns that large on land. Also, such weapons were designed to attack -- and were only really useful against -- fixed fortifications. When rail guns were available but no enemy fortifications were within reach, they were used to harass concentration areas in the enemy rear.

About the only place where the analogy stands up is in the fact that both laserstars and rail guns are vulnerable to asymmetric attack. Rail guns were vulnerable to air attack and even enemy ground forces (if the gun can't be evacuated quickly enough in the face of an enemy attack). Laserstars would be vulnerable to saturation kinetic attack at least, and perhaps attacks we haven't even thought of.

Byron said...

I have several thoughts here. First off, I also don't see laserstars engaging in low-orbit combat. I can see them shooting at things in low orbit as fire support for operations there, but putting a long-range laserstar in low orbit is like taking a non-gun-armed F-4 into a dogfight low over Vietnam. It's just a bad idea.
Second, I still see lasers as divided into machine gun and cannon types, based on pulse rate. That comment sort of got washed out by the other stuff in SWXIV.
Lastly, what will be the difference between CW and pulsed lasers in terms of weight and efficiency? I know pulsed is better for a given amount of energy, but I'm far from certain that that's the whole story. What if CW lasers are far more efficient or have much higher specific powers?

Tony said...

Re: Byron

I think astrodynamical considerations would require that "stationar" laserstars be positioned in high orbits. This eliminates kinetic sneak attacks from below their horizons with short in-line-of-sight times before impact.

But I don't think deep space battle constellations will ever be implemented, because they're just too expensive in terms of redundant drive systems, sensor systems, power systems, and spacecraft structure. Deep space will be the realm of ships and missiles.

WRT pulsed vs continuous lasers, I think in practical combat lasers are going to be pulsed. Pulse length's might be varied for different types of targets and engagement dynamics, but sontinuously blasting away, using the laser like a sword, just wastes energy.

Tony said...

Rick:

"Precision and the battlefield don't mix. There is a lot of precedent for the general observation that pinpoint accuracy is hard to achieve amid the turmoil of combat. On the other hand, in the contemporary era precision-guided munitions have demonstrated capabilities that would have startled military observers of an earlier era."

A couple of observations:

1. My comments about precision and military applications weren't really aimed at the combat environment in the sense of what the enemy can directly do, since in space combat, only one or two hits will (or should be) enough. They have more to do with achievable levels of precision given the dynamics of saturation attacks with small targets. Also, for engaging single, large targets, I have concerns about the resources available to pay for high levels of refinement in multiple examples of already very expensive machines.

2. Modern precision munitions are all examples of active homing of missiles on precisely defined coordinates using GPS, or designator (radar or laser) reflections. Lasers are about pointing precision, which is an entirely different exercise.

Anonymous said...

Ok, Laserstars in low orbit: good for defense, bad for offense. Laserstars in battle constellations: literally the 'big guns' of the fleet; very long range CW would be good for the opening phases; medium range CW or pulsed would be good for countering drones and kinetics, the most flexible of the type; short range pulsed would be good for anti-kinetic fire (and any smaller ships that get too close).

As far as the lasers themselves, using phase amplification (several laser tubes combine their output) would be good if you needed both a huge 'keel-mounted' weapon, and several smaller turrat mounted ones; the secondary mirrors could either feed the main mirror or redirect the induvidual beams into the secondary turrats.
Laserstars, in my opinion, would be just one of a number of classes of 'robodestroyers' that would be controled by manned command vessels that in turn would provide local command & control, limited maintanance, refuel/rearm/reprograming for the drones and the 'robodestroyers' of the battle constellation. Laserstars might not win the battle for you, but you'll probably lose if you don't have them and the other guy does.

As far as I can remember, during WWI the rail guns' were most successful at shelling cities...if they could have kept up with the troops, didn't take a battalion a day to set up for one shot, then they might have had better utility in combat; the laserstars would be like railroad cannons that could keep up with the other forces and actually be used in concert with other forces, rather than in isolation. And, that, I believe is what Rick was getting at.

Ferrell

Tony said...

Re: mobile constellations

On-orbit constellations make some degree of sense, because they can be maintained on-orbit with a minimum of propulsive effort -- attitude jets, basically. Mobile constellations require multiple high-performance, high expense military grade propulsion systems, maybe not total but some duplication of sensor suites, and a degree of overequipment for maintenance float. Just like torpedo boats make sense for inshore patrolling and defense, so do constellations of unmanned weapons platforms for planetary defense. But if you're trying to project power overseas or overspaces, there's nothing to rival a fully-equipped, multiply armed, manned ship.

Milo said...

The question with having multiple types of weapons (like guns and torpedos, or lasers and kinetics) is, when is it better to fit a mixture of them onto the same ship, and when is it better to spread them out on separate ship classes (like torpedo boats) that work in concert in the context of a larger fleet?

Tony said...

Milo:

"The question with having multiple types of weapons (like guns and torpedos, or lasers and kinetics) is, when is it better to fit a mixture of them onto the same ship, and when is it better to spread them out on separate ship classes (like torpedo boats) that work in concert in the context of a larger fleet?"

And the question is answered by the specific economics for a given set of requirements. Operating at long distances from base, for considerable lengths of time, demands large, multi-capable vessels. Even when you have vessels heavily weighted towards a particular capability, like battleships and aircraft carriers, they wind up being the largest vessels, requiring the most logistic and tactical support. Smaller -- but still relatively high endurance -- vessels, like cruisers and destroyers, tend to have the widest variety of capabilities.

With laserstars, we have a small vessel with a single primary capability, like a pursuit fighter in WWII, and, like that fighter, high independent maneuverability requirements over a short period of time. To avoid ridiculous expenditures on redundant interplanetary drives, they would have to be moved from planet to planet on carrier vehicles. That would make a laserstar a...space fighter. Wait a sec...

Rick said...

A milliarcsecond is considered military grade precision, but a regular 30cm wide missile can only be targeted from 340km out.

An important quibble here - you can target it at longer range; it will merely be smaller than the pixel size of your detector and the spot size of your beam.

(After all, we can see stars with the naked eye; we just can't resolve them.)

To take your example, if you zero in on the 30 cm diameter missile from 3400 km out, your beam will be 3 meters in diameter, and only 1 percent if the beam energy will actually be hitting the target.

This is 'inefficient,' but if the beam is powerful enough to erode the armor, it is still effective. Assuming my laser is powered by a reactor (or solar array, whatever), I'll start defensive fire as soon as the incomings are within the damage-causing range of my beam, even if I am 'wasting' most of my zapping power until they get closer.


Second, I still see lasers as divided into machine gun and cannon types, based on pulse rate. That comment sort of got washed out by the other stuff in SWXIV.

Lastly, what will be the difference between CW and pulsed lasers in terms of weight and efficiency?


My impression is that a pulse laser is best thought of as a long-range jackhammer - it lays a train of zaps onto the target, each zap (ideally) causing impulsive shock, shattering off a bit of the target surface.

Melting/sublimating is the slowest but surest way to zap through armor - impulsive shock is faster, IF your pulses are intense enough to produce it on the target surface.


My reference to railroad guns was probably not the greatest choice, since the analogy was not to their military mission, but to being the 'biggest mobile gun' available.

Thucydides said...

Laser weapons have huge theoretical advantages in performance over other weapons, so people will be continuing to work on them.

Even for patrolling LEO a high orbit will be the preferred location to keep people from "sneaking up" with kinetics and provide a wide horizon.

WRT implausible midfuture constellations, multiple platforms in the constellation can provide 3D range information for all the weapons systems in the constellation. The lasers can provide the analogous role of a railway cannon by reaching out and hitting enemy sensor platforms and busses before they come into range of your systems.

Mounting auxilliary weapons like KKV busses on the platform will have performance issues and induce a lot of vibrations, so a laserstar should be a "pure" system.

Tony said...

Thucydides:

"WRT implausible midfuture constellations, multiple platforms in the constellation can provide 3D range information for all the weapons systems in the constellation."

So can other ships in a squadron. If you can datalink drones, you can datalink larger vessels.

"The lasers can provide the analogous role of a railway cannon by reaching out and hitting enemy sensor platforms and busses before they come into range of your systems."

Railway cannon were for engaging fortifications. The closer they were, the more precise in hitting point targets. If one was looking for an analogy, perhaps one should consider the limits of pointing precision, not the size of bang at the other end. Something that always seems to be missing from these discussions -- the bigger the gun, the harder it is to point precisely. I see absolutely no reason why a laser cannon should be any different. Even if the base levels of achievable precision are greater, the bigger and more powerful you make the laser zapper, the larger everything else gets as well, the more energy it takes to get it moving in one direction, the more energy it takes to slow it down, the less precision per unit of engagement time all of this is, etc.

"Mounting auxilliary weapons like KKV busses on the platform will have performance issues and induce a lot of vibrations, so a laserstar should be a "pure" system."

Considering lasers as theoretical systems, divorced from reality? yes. Considering the technical and tactical constraints imposed by reality? Not so much.

Milo said...

Rick:

"An important quibble here - you can target it at longer range; it will merely be smaller than the pixel size of your detector and the spot size of your beam."

Which means that you can't reliably hit it with one sniper shot. You might, however, still be able to hit it by making potshots until you luck out.



Thucydides:

"Even for patrolling LEO a high orbit will be the preferred location to keep people from "sneaking up" with kinetics and provide a wide horizon."

Hmm. How hard is it (in delta-vee terms) to change from one low orbit to a differently-inclined low orbit, compared to moving between high and low orbits?

Maybe you could have a boarding/intercept craft in low orbit, supported by sensors and fire support from a higher orbit.

Byron said...

Rick:
My impression is that a pulse laser is best thought of as a long-range jackhammer - it lays a train of zaps onto the target, each zap (ideally) causing impulsive shock, shattering off a bit of the target surface.

Melting/sublimating is the slowest but surest way to zap through armor - impulsive shock is faster, IF your pulses are intense enough to produce it on the target surface.

That's not exactly what I meant. I know of the different damage mechanisms, but in terms of tactical use, what's the difference between a CW laser and a kilohertz pulsed laser?

Tony:
WRT pulsed vs continuous lasers, I think in practical combat lasers are going to be pulsed. Pulse length's might be varied for different types of targets and engagement dynamics, but sontinuously blasting away, using the laser like a sword, just wastes energy.
I'm not suggesting using it like a firehose. You would target and then fire. This is obvious. However, particularly if accuracy isn't great, a CW or high-pulse laser might be used to increase the chances of a hit.

Tony:
But if you're trying to project power overseas or overspaces, there's nothing to rival a fully-equipped, multiply armed, manned ship.
I'm not too sure about this. I think that drives will scale rather linearly (not exactly, but fairly close, particularly if they're modular.) And I'd keep humans to a practical minimum.
That dictates a lot of smaller ships, rather than a few larger ones. And I've never claimed exactly one weapon or weapon type, but that they will be dominated by one, like battleships or tanks.

Tony said...

Byron:

"I'm not suggesting using it like a firehose. You would target and then fire. This is obvious. However, particularly if accuracy isn't great, a CW or high-pulse laser might be used to increase the chances of a hit."

I think I'd use a relatively high pulse rate for short ranges or more well protected targets. But at longer ranges I'd reduce the pulse rate and concentrate on precision.

"I'm not too sure about this. I think that drives will scale rather linearly (not exactly, but fairly close, particularly if they're modular.) And I'd keep humans to a practical minimum.
That dictates a lot of smaller ships, rather than a few larger ones. And I've never claimed exactly one weapon or weapon type, but that they will be dominated by one, like battleships or tanks."


Both battleships and tanks are optimized for fighting other battleships and tanks. laserstars are optimized for fighting other laserstars. If your enemy doesn't have them, or it's more economical for you to use kinetics against eney laserstars (as it turned out to be more economical and effective to use aircraft and torpedoes against battlships, or aircraft against tanks) then you might not even bother with laserstars. I certainly wouldn't -- I've always trusted homing swarms over behemoths relying on pointing precision.

Milo said...

Byron:

"I know of the different damage mechanisms, but in terms of tactical use, what's the difference between a CW laser and a kilohertz pulsed laser?"

If they have the same total power, then a pulsed laser will always be no less effective than a continuous laser (since it's still delivering the same amount of energy that will still serve to melt through the target just as readily - or more, since there's less time for heat to be conducted away from the impact point), and often more effective (due to the addition of a new damage mechanism, namely excavating craters).

If your continuous lasers have significantly more total power than pulsed lasers, then it's less trivial to determine which is better.

Also, due to the different damage mechanisms, pulsed and continuous lasers are most effectively protected against using different armors. Steel, in particular, is quite weak against continuous lasers (I think titanium is too). Carbon nanostuff, however, will work pretty well against everything.

(Oh, and what does the "W" in "CW" stand for?)



Tony:

"I think I'd use a relatively high pulse rate for short ranges or more well protected targets. But at longer ranges I'd reduce the pulse rate and concentrate on precision."

If you can freely vary your pulse rate and have aiming precision good enough that you can keep your weapon trained on the same spot on the enemy while you drill through, and your goal is to drill as deeply into the enemy ship as possible without caring about how thick the wound channel is, then the most efficient pulse rate is the one where each individual pulse excavates a crater just slightly larger than your spot size. As the range increases, and spot size increases with it, you will need to lower your pulse rate in order to deliver more energy with each pulse. If your spot size is large enough that your laser cannot make a hole thicker than the spot size even with the most powerful pulse it's capable of, then you're stuck using the most powerful pulses and slowest pulse rates you have. If your enemy is moving fast enough that you cannot keep your laser trained on one spot for multiple pulses (even ones that are mere milliseconds apart), then again you have to use the largest and slowest pulses you can.

Note that I made the assumption that wound depth is far more important than wound thickness. This is probably reasonable, particularly if you're shooting at armor, but there can be situations where it isn't the case.

Also note that pulse patterns will probably not be monotonous - you're more likely to have a "burst" of several pulses milliseconds apart, then a longer wait of multiple seconds, then another burst, and so on. The speed of individual bursts would be governed by how long any individual pulse's crater takes to form (you don't want pulses to interfere with each other), while the time between pulses would be governed by how much overall power your laser and capacitor can handle (for example, as limited by waste heat).

Jim Baerg said...

I've been tending to skim over the space warfare threads so I may have missed a perfectly good answer to this question.

A laser as a weapon needs mirrors coated with something very reflective in the range of wavelengths the laser might operate at. Otherwise the heat lost in your lasers optics becomes almost as destructive to you as the laser is to the target.

Couldn't the enemy just paint your target in that substance & make your laser an ineffective weapon?

I do recall references to "eyeball frying contests". Are some people thinking that burning out the enemies sensors will make his spacecraft useless? How cheap would redundant sensors be?

Milo said...

Jim Baerg:

"A laser as a weapon needs mirrors coated with something very reflective in the range of wavelengths the laser might operate at.

Couldn't the enemy just paint your target in that substance & make your laser an ineffective weapon?"


The short version is, your laser doesn't melt your mirror because the beam is spread out over a large area. When the beam hits the enemy, it's focussed onto a spot significantly smaller than your mirror, so more energy is concentrated on a small amount of stuff.

jollyreaper said...

I don't quite like the comparison to a railroad gun because those things were more stunts than useful. The real question is whether the laserstar represents the ravening beam of death killing all within range or whether the effects are more limited.

The kind of impression I generally have is that they'll be powerful but kept back for protection. The smaller ships would be the ones you are willing to risk, not so much as scouts but as things getting close to dangerous areas. Boarding installations, other ships, low orbit around planets, these ships are expendable in ways laserstars are not.

The comparison might work better with the railgun ships the navy wants to build. 200 mile range with cheap hypersonic rounds hitting withthe same KE as a cruise missile. A ship like that you'll keep way offshore for protection and risk the littler, cheaper ships for ASW or close shore work, the kinds of things that make you vulnerable to torps, mines, and anti-ship missiles.

jollyreaper said...

The question with having multiple types of weapons (like guns and torpedos, or lasers and kinetics) is, when is it better to fit a mixture of them onto the same ship, and when is it better to spread them out on separate ship classes (like torpedo boats) that work in concert in the context of a larger fleet?

That question's come up time and time again. In the age of sail you wanted the greater weight of guns concentrated in hulls that could survive the fight -- 72 vs. 32 is no contest. In the age of missiles, every ship in your fleet can fire and hit with equal power and so you want to disperse your missiles as widely as possible, especially considering that even a single hit could mission-kill a hull.

My bias is for assuming that space weapons will be devastating, any hit crippling. So many smaller ships unless there's some compelling reason for going bigger -- the sea-keeping capabilities for long deployments with American and British warships is a good example previously mentioned.

Anonymous said...

Milo: CW stands for Continuous Wave; instead of a series of pulses, the beam is a single, unbroken sine wave. I hope that clears things up for you.

The main reason for a mix of weapons would be flexibility; the wider the range of missions or roles a ship can perform, the more flexible your space force is, regardles of its size. Besides, the more types of threats you can defend against or the more types of threats you can present, the better.

Ferrell

Stevo Darkly said...

[Off-topic here, but I'm afraid it might be overlooked elsewhere. Just wanted to mention that I have posted a 2-part question/scenario about FTL, relativity and causality in the "FTL Part II: Just Plain Cheating" thread. And also, both of those posts have disappeared. Help, Rick?]

Sorry for the interruption.

Thucydides said...

The only true constellation of space weapons ever extensively studied has some interesting factoids to integrate with today's technology and whatever sorts of political assumptions you are making about the plausible/implausible midfuture.

SDI studied multiple weapons and basing systems. Although they moved away from lasers, particle beams and railguns as being too far beyond the state of the art in the 1980's, laser proponents claimed that constellations of up to 200 would be needed to provide global coverage. (Some proposals called for far fewer, but 200 seems reasonable to include weapons off line for testing and repair, and to absorb battle damage).

Kinetic Kill Vehicles were also studied, and the preferred solution became "brilliant pebbles" operating independently in orbit. It was estimated that 7000 needed to be on station to provide global coverage.

Terminal defense did not seem to have received as much attention, but 1970 state of the art weapons like "Sprint" were capable of accelerating at 100 g and intercepting warheads at 30,000m altitude in 15 seconds. Greater performance had been demonstrated with the HiBEX experiments.

"Pop up" interceptors based on the Excalibur X ray laser program were also proposed, but once again the state of the art did not support these weapons. It is a bit unclear how many would have been needed; although the boost phase interceptors would have thinned out a lot the X ray interceptors would join the fight in the mid course phase when the sky was filling with decoys and penetration aids.

One thing seems clear, the use of brilliant pebble KKVs required vast numbers to cover the globe just due to the time and space factors.

We can update this; today advanced prototype laser weapons do exist on ground, air and sea platforms and have intercepted and destroyed targets like mortar rounds and missiles in flight, and set small ships on fire at sea, operating in the atmosphere from land, air and sea mounts. Usually the platforms are in motion and the conditions are far tougher than any space environment. Railguns are also in advance prototype development, 33 Mj railguns have been demonstrated and the US Navy is working towards a 64 Mj weapon.

Like it or not, many of our favorite tropes are either available now or will be within a decade.

KraKon said...

"But there will be, for example, kinetics that may be best countered by finding ways to take out their launchers before they launch, rather than shot down on incoming trajectories. Food for thought."

That would be counterattack! In the case of chemical rocket missiles, they can be dumped overboard, no launchers to shoot at and no means of preventing the opponent from firing.

"Second, I still see lasers as divided into machine gun and cannon types, based on pulse rate."

The problem is that it is just too easy to have a single laser do both modes. An assault rifle that can be set to auto or three burst is still an assault rifle.

"What if CW lasers are far more efficient or have much higher specific powers?

The main advantage of CW lasers is that they are cheaper and lighter, as you don't have to install modules that can modulate pulse length, and structures that support high peak intensities. You will have however the same end effect as CW beams if you set a pulse laser to very long pulses, or very low energy, extremely high rate of fire (not sure about the last one).

"I think astrodynamical considerations would require that "stationar" laserstars be positioned in high orbits. This eliminates kinetic sneak attacks from below their horizons with short in-line-of-sight times before impact."

I only suggested low orbit laserstars because the have a FRIENDLY base on the ground. No sneak below-the horizon attacks, as that will be dealth with by ground-based lasers. The whole concept is layered defense. The ground based laser penetrates atmosphere but spreads out to dismal range. The low orbit laserstar has very long range, but needs maintenance, resupply, and launch costs make it better to have an easy to maintain, insignificant lag laserdrone near you than isolated a few thousand km away. After all, when the enemy is 200000km away, shooting from high or low orbit can't make much of a difference.

"Ok, Laserstars in low orbit: good for defense, bad for offense. "

Yes, they are in a defensive role.

KraKon said...

"Operating at long distances from base, for considerable lengths of time, demands large, multi-capable vessels. Even when you have vessels heavily weighted towards a particular capability, like battleships and aircraft carriers, they wind up being the largest vessels, requiring the most logistic and tactical support. Smaller -- but still relatively high endurance -- vessels, like cruisers and destroyers, tend to have the widest variety of capabilities."

That is only valid at sea, when increasing payload only requires a minimal increase in powerplant size or structure. In space, where everything is perfectly proportional, it is better to have several smaller ships with small powerplants, rather than increasing the mothership's total mass by mass of added component*mass ratio+powerplant power increase, in terms of mass needed.

"That would make a laserstar a...space fighter. Wait a sec... "

Except if take note that the laserstar doesn't swoop and roll and dodge, and has a crew of 12+ to share the merit of prowesses accomplished by the young hothead.

"An important quibble here - you can target it at longer range; it will merely be smaller than the pixel size of your detector and the spot size of your beam."

The beam spot size is still much smaller than the target at these ranges. It goes from 4.8 to 0.12cm, so I think the problem here is beam wander and not spot size.
The airy disk distribution model of hits would also be skewed by having the missile with an empty tube spot on in the region of most probability.

"To take your example, if you zero in on the 30 cm diameter missile from 3400 km out, your beam will be 3 meters in diameter, and only 1 percent if the beam energy will actually be hitting the target."

Wavelength: 100nm, mirror: 10m, pulses: kHz.
I think here that I need an extremely complicated calculation to find out the airy disk diameter, the surface area of the ring (Internal 20cm, external 33cm) crossing the disk, and band covered to find the mean probability of hits for that region.
Then I work out the mean for the whole transit.
Then I work out the mean penetration, giving different factors including incoming velocity, number of missiles, how many laser spots converging onto the same missile, if those spots are likely to overlap, doubling or tripling the penetration rate, or not....
The latter is important as according to my calculations (100% hit rate from 1200km) the missile requires 0.29mm of armor with no overlaps, 5mm of armor with full overlap of all opposing 18 laserstars...

KraKon said...

"Considering lasers as theoretical systems, divorced from reality? yes. Considering the technical and tactical constraints imposed by reality? Not so much. "

Again, I beg you to consider the ship and the laser to be two seperate systems, held together only because the power generator is on your ship, and the heat goes from the laser to your heat sinks; so it is entirely possible to have several different weapon systems (kinetics busses, BALs...) that do not interfere with each other. One way of doing this is the laser-in-a-can ship arrangement, with the kinetics on the outside of the can.

"How hard is it (in delta-vee terms) to change from one low orbit to a differently-inclined low orbit, compared to moving between high and low orbits?"

I'm pretty sure getting to a higher orbit costs much more in time and propellant than a simple inclination modification. After all, one has a net energy of 0 (differeng inclination, but same height) while the other has a negative net energy as you have increased your gravitational potential energy (by going higher).

"and your goal is to drill as deeply into the enemy ship as possible without caring about how thick the wound channel is,"

The strange thing is that with my lasers, if set at 1MHz, on an inert surface of armor, I can get holes 500m deep and 1.2cm wide. I'm not sure that aspect ratios of 41667:1 is plausible...but why, other than for the fact that you can't train the beam on the same 1.2cm wide spot for a full second 2000km away? Maybe the armor expands and fills in the hole, or molten material from the depths of the crater comes rushing up at the beam, and stuff like that...

"My bias is for assuming that space weapons will be devastating, any hit crippling"

What if it wasn't? On my ships, a mere 1.2kT of armor (20% of ship mass) can protect it for days against a 4GW, 100nm beam, and you need 15 consecutive impacts from 10kg, 5km/s warheads to go through the FIRST layer of armor. The second layer of armor consists of steel plates that ruin the day of less dense penetrators, that try and skip the mass of carbon.
It is then reasonable to ask-if ten small ships die at the first impact, while a ten times more massive ship requires hundreds of impacts (external velocity of the armor surface is higher when the cylinder's radius is bigger, and while armor THICKNESS might not go up linearly (to the cube root?) the faster rotating shell can spread impacts more efficiently), why not make big ships?

"Like it or not, many of our favorite tropes are either available now or will be within a decade."

YAY!
So war becomes ever more technologically based, costing of course ever more, meaning less and less units are produced, to the point where the lack of symmetrical combat situations and the units involved in them leads to inconclusiveness of the effectiveness of what new tech we've just implemented! More speculation ensues, until a rising power decides to take a chunk out of the superpower's confidence by taking as many killsats/railgun-equipped destroyers the dirt cheap way.

Anonymous said...

To be honest, I still see laserstars (assuming they are capable of interplanetary travel) as being a reasonably close analogue of battleships. Laser beams have similar advantages (speed, difficulty of interception) and disadvantages (lack of homing ability, shorter range) relative to kinetics that gun shells have to anti-ship missiles and torpedoes. They are therefore similarly useful against faster-moving targets at shorter ranges and slower-moving/predictably moving/immobile targets at longer ranges.
To me, the equivalent of railway guns would be orbital 'fortresses'/'battlestations' (possibly built into smaller asteroids) with limited ability to change orbit, used for long-range support of more mobile forces, defence of near-planetary space against invading forces, or as siege weapons against heavily hardened targets.
Even larger/longer-ranged lasers, built into larger asteroids or planets/moons lacking atmospheres might have interplanetary range, and would be roughly equivalent to ICBMs.

R.C.

jollyreaper said...

The fortress to my mind is two cases. The big fort is the celestial body itself with powerful weapons not needing to be compact for movement.

The little fort is what we call a battlestation but it would not need to be stationary. Depending on the setting, the fort may be no good for ftl or very slow for realspace movement. Forts would really come into their own in a jump point setting. Any attacker would have a pile of forts to deal with in any defended system.

I'm thinking that you'd probably see one manned fort and dozens of automated satellite forts. Not much brainpower is needed to run reactors and shoot at anything that fails IFF.

Where things get tricky is if you have shields and superlasers. Kinetic weapons all get vaporized and so the only way to kill a fort on the other side is to send through an even bigger pile of shielded ravening death beam dreads.

Jim Baerg said...

Milo:
"Hmm. How hard is it (in delta-vee terms) to change from one low orbit to a differently-inclined low orbit, compared to moving between high and low orbits?"

LEO speed is about 8 km/s. Add 3 km/s & you are almost at escape speed. Vector add 3 km/s to give 8 km/s in a different direction & the new orbit is as 21.6° from the old. So unless the desired inclination change is small it is easier to go to a higher orbit.

Since orbital speeds drop rapidly with distance from the planet you are orbiting, inclination changes are much less costly for high orbits.

Tony said...

let's see...

1. If I was worried about enemy armor, I wouldn't be screwing around with lasers, I'd be hitting the enemy with kinetics at as high a relative velocity as I could arrange. That goes for even very thick armor that a single small kinetic might not penetrate. Shock damage throughout the vessel and spall off the back side of the armor system ought to do a lot of destructive work for me. (Because I'm not shooting a rod-shaped penetrator at the enemy, just a slug.)

2. While propulsion requirements theoretically scale proportionally with mass in space, there are still overhead costs that favor fewer, larger vessels for a given amount of payload. Propulsion plants scale more linearly than they do at sea, but not perfectly linearly. The same goes for structural components. But there are plenty of items that absolutely don't scale lineraly -- sensor systems, control systems, tankage mass (volume scales by the third power, surface area by the second), etc.

Tony said...

What else...

3. Brilliant pebbles were individually very much smaller than laser or particle beam satellites. In terms of launch vehicle requirements, 7,000 of them may in fact have required less lift mass than 200 beam weapon satellites.

Scott said...

If my target has some kind of armor (carbon exotics or aerogels), I'd introduce them to EFPs. 1kg of copper sitting on top of RDX gets a velocity of 6500m/s from the explosion, plus whatever the missile's closing velocity was.

As I have said repeatedly, I don't see Laserstars as a single-weapon platform. Any space warship will have different weapons for different missions, just like every modern military item does.

An infantryman has a knife, grenades, and a rifle. A tank has the main gun (with multiple ammo types) and several machine guns, plus the tracks. A fighter plane has guns, short-, medium-, and long-range missiles. Ships have small guns for speedboats, small guns for point defense, larger guns for military craft, small missiles for point defense, small missiles for AA, larger missiles for anti-ship, and torpedoes (usually for antisub).

Even sailing ships of the line were not weapons monocultures, since they mounted relatively light guns, heavy guns, short-ranged carronades, and antipersonnel 'swivel' or 'rail' guns, in addition to the sharpshooters in the fighting tops.

Raymond said...
This comment has been removed by the author.
Raymond said...

Damn Blogger login without the email option...

Milo said...

Ferrell:

"Milo: CW stands for Continuous Wave; instead of a series of pulses, the beam is a single, unbroken sine wave."

Ah, thanks. I know light is a wave, I just didn't expect it to be particularly relevant to what we're using it for right now. A particle beam weapon, say, could in principle also be used in steady or pulsed modes (although even a "steady" particle beam would be pulsed on the quantum level).



Tony:

"But there will be, for example, kinetics that may be best countered by finding ways to take out their launchers before they launch, rather than shot down on incoming trajectories."

So that just leads to the question of whether you would rather be taking out those launchers (fast enough to keep them from firing, since a launcher which has expended its ammunition is a non-threat) with kinetics or with lasers.



KraKon:

"In the case of chemical rocket missiles, they can be dumped overboard, no launchers to shoot at and no means of preventing the opponent from firing."

There may not be a simple obvious "gun" you can fire at, but you can still just blow up the entire ship, or at least its ammo hold (where unfired missiles are kept), and you can potentially hit the launching mechanism (even if that launching mechanism is a couple of guys with spacesuits).


"The main advantage of CW lasers is that they are cheaper and lighter,"

By how much? A 10% saving (just to make up a number) would probably not be worth the reduced effectiveness of continuous lasers.


"In space, where everything is perfectly proportional,"

Not perfectly. Equipment tends to be more mass-efficient in larger sizes, and often has a minimum viable size (you can't make a watch battery sized nuclear reactor).

But yeah, it'll be fairly close to proportional beyond a certain point.


"Except if take note that the laserstar doesn't swoop and roll and dodge, and has a crew of 12+ to share the merit of prowesses accomplished by the young hothead."

So, 12+ young hotheads? Should be a good setting for some personal drama...

But yeah, actual battle is going to be kinda boring. "We have a target incoming." "Okay, so set the computer to start shooting it when it's in range." "Done. ...Okay, it's in range now, the firing mechanism is keeping steady." "Is it blown up yet?" "No." "Are we blown up yet?" "...Shut up." "...How about now?" "SHUT UP!"


"I'm not sure that aspect ratios of 41667:1 is plausible...but why, other than for the fact that you can't train the beam on the same 1.2cm wide spot for a full second 2000km away?"

Well, if the target is moving even slightly, then a straight line from your position, carved into its armor, will not remain a straight line from your position forever. Beyond a certain point you won't be able to see down the wound channel anymore.


"Maybe the armor expands and fills in the hole, or molten material from the depths of the crater comes rushing up at the beam, and stuff like that..."

Hmm, that too. I hadn't considered that. I'd just been assuming that you can always blast out a crater, but in a really deep hole, it's going to be hard for the molten armor to blow clear of the crater.

Milo said...

R.C.:

"To me, the equivalent of railway guns would be orbital 'fortresses'/'battlestations' (possibly built into smaller asteroids) with limited ability to change orbit, used for long-range support of more mobile forces, defence of near-planetary space against invading forces, or as siege weapons against heavily hardened targets."

You can't have a siege weapon without the ability to change orbit, unless you're being pushed around by a tug. Otherwise how would you get to the place you're besieging?

You might have some "slow" ships with only a fraction of the delta-vee of a "fast" ship", meaning they'll take a while to catch up to the rest of your fleet, but they'll still have a pretty powerful engine. Personally I would rather just add some more engines.

Our conventional picture of battlestations is predicated on the intuitive notion that a really huge object simply can't move very fast, which is rather questionable is space (if you have the budget to build a really huge weapon, then why not a really huge engine to push it around?). Actually, now this is making me rethink space stations in general...



Jollyreaper:

"The big fort is the celestial body itself with powerful weapons not needing to be compact for movement."

Corollary, you can also fortify moons orbiting a planet. You get both the advantages of a large mass of rock and of not needing to shoot through an atmosphere.


"Where things get tricky is if you have shields and superlasers."

If you have shields, then tactics will be strongly influenced by the chosen rules for your shielding technology: what it can/can't defend against, what it costs to use, how it acts when you start overwhelming it...

It is entirely reasonable - as reasonable as shields are to begin with, anyway - to have shields which only defend against lasers and not kinetics, or vice versa, which would be a useful contrivance for enforcing the weapons you want to use. (In fact charged particles are the one thing that we can plausibly shield against with near-future technology, using magnetic fields.)



Scott:

"As I have said repeatedly, I don't see Laserstars as a single-weapon platform. Any space warship will have different weapons for different missions, just like every modern military item does."

The term "laserstar" puts me in the mind, at least, of a ship that has a single laser system which takes up significantly more mass than all of the ship's other weapon systems combined. Otherwise it's not a laserstar, just a ship with a laser on it.

Thucydides said...

One of the issues with brilliant pebbles and the reason the eventual basing mode was to have each weapon in an independent orbit inside a "lifejacket" was the considered vulnerability of busses or garages full of KKV's to enemy countermeasures.

Having 7000 independent targets means the enemy needs 7000+ interceptors (or some means of rapidly dealing out death 7000 times) to clear the sky. Now in practical terms you don't need to shoot down all 7000, but enough to clear a path for the ICBM launch and deployment of the warheads and penetration aids from the missile busses. This would ensure enough warheads got through the midcourse and terminal defenses to cause catastrophic damage to the United States.

For a space war setting, sending 7000 brilliant pebbles on independent trajectories from Earth to (say) Mars isn't a practical proposition but this means any interplanetary bus or carrier spacecraft becomes vulnerable; shoot it down and you loose all the brilliant pebbles as well. Using a powerful booster bus to bring the KKVs up to speed is also fraught with difficulty, the plume from the booster will advertise where the KKVs are, and even wildly powerful busses like the Sprint or HiBEX would simply attract attention from across the Solar System, plus provide a superb targeting solution for the defender (especially if the bus can be attacked before the KKVs disperse).

Scott said...

Milo:

Picture this for a minute: The ship is 300m long. Most of that length is the truss between the reactors and the people tank, but since we have that length, we built in a rather scary EUV laser (~40nm wavelength, if I understand the math correctly). The largest feasible mirror is 'merely' hubble-sized, but I have 4 of them available, plus 8 more secondary mirrors half that area and 16 'PD' mirrors a quarter the area of the primaries. In addition, I have some HiBEX missiles carrying annular-frag warheads, and some bigger, slower 'torpedoes' carrying large EFPs and PENAIDs. Oh, and some railguns or no-joke Phalanx guns for really short-ranged beatings.

One laser generator as the *primary* weapon, and an array of other weapons for PD and maneuver constraints (to force the target into your laser arc or risk terminal kinetic strikes). The laser is the single heaviest weapon on the ship, the kinetics and missiles are also very limited in ammunition capacity.

Still sounds like a laserstar to me. What about that description doesn't sound like a laserstar to you?

Rick said...

KraKon -

The beam spot size is still much smaller than the target at these ranges. It goes from 4.8 to 0.12cm, so I think the problem here is beam wander and not spot size.

I haven't repeated the calculations, but ideally the spot size of your beam and your fire-control pixel size are on the same order. If there is jitter/wander, you can defocus the beam to fill whatever cross section you can effectively aim at. Given sufficient power, you can slowly erode away whatever armor you're zapping.

And, if the laser draws power from your drive reactor, and is designed for the job, there is no inherent reason why you cannot hold the beam on that target, to whatever is the limit of effective aim, for hours. It isn't like your magazine is gonna run low on photons.

For this purpose I'm not concerned with the details of the beam, pulse rate or even CW. Consult Luke's website to 'tune' the laser. So long as it gets the target surface hot enough to melt, or for brief (repeated) intervals hot enough for impulsive shock, you can erode away the target, and keep doing it pretty much until you knock out the target or someone makes you stop.

Yes, this is weirdly contrary to our familiar experience of weapons, but that is not a disproof. Your drive engine, presumably, can deliver and handle gigawatt loads for weeks at a time. So there is no inherent reason why your laser installation can't handle 200-megawatt loads, or thereabouts, for Pretty Damn Long.

If the precision limit on aim is large enough (my first point drawn from Tony's critique), this may not be a militarily useful capability. But if lasers are militarily useful at all as direct damage weapons (not just target designators), I suspect laserstars will be militarily useful.

Rick said...

any interplanetary bus or carrier spacecraft becomes vulnerable; shoot it down and you loose all the brilliant pebbles as well.

And a couple of ways to shoot it down come to mind.

1) A laserstar.

2) Another, probably smaller, kinetic bus.

The bus is necessarily big, a much easier target than its submunitions, and whatever defenses or countermeasures you provide for it come out of its ultimate deliverables. (This includes firing some of its target seekers prematurely to engage the counter-bus or laserstar.)

On an entirely separate note, 'shoot down' is a wonderfully figurative expression when applied to space combat!

Milo said...

Heh. If you destroy an object in interplanetary transit, it will still coast past the destination planet on schedule, but (due to its engines having been destroyed) unable to stop, and therefore it will sling past the destination planet and fly off. If it is above solar escape velocity then that's the last you'll see of it, otherwise it will enter an elliptic orbit and there is a small space debris risk of it meeting your planet again someday.

If a spacecraft's main engines are trashed but any component of the vehicle is still operative (for example its weapons, or the guidance systems of its submunitions), then it will get one chance to use those as it hurtles past.

However, this was assuming instant burns. If you use an ion engine, then you will be spending the majority of your trip thrusting (at low acceleration) rather than coasting to your destination. Thus, being interrupted midway would probably throw you off completely and prevent you from ever getting near your target.

Anonymous said...

Milo:

I did say that the fortresses would have limited ability to change orbit, not no ability. I was attempting to come up with a laser weapon that would share a railway gun's mobility limitations, compared to a laserstar or a battleship. Spacecraft that are merely larger, slower laserstars might be more comparable to the warships known as monitors, which had large-calibre guns, but low speed and poor seakeeping, and were used for coastal defence or support against shore targets.

R.C.

Geoffrey S H said...

@ Rick:

If a space craft's offensive weapons can be used to take out other offensive misiles, then might that lead to small volleys of missiles fired in his attempt to get one side to waste more missiles in an attempt to decisively stop your missile groups... so that you can eventually build up an overwhelming stockpile of remaining missiles and then send them against him*? That could lead to some interminably long space-fights.

*Assuming you can retain a stockpile large enough to overhwelming bith the laser pds, and the armour, and that both sides are equally matched, with no laser stars intervening.

KraKon said...

"Depending on the setting, the fort may be no good for ftl or very slow for realspace movement. Forts would really come into their own in a jump point setting. Any attacker would have a pile of forts to deal with in any defended system."

As usual, we can twist around things.
On realspace-a fort can afford to mount a ginormous engine, or a more decent engine but using its own mass as propellant for a very large mass ratio. The end result is, if you give it enough time, the fort can get to anywhere, and with a very high velocity. The thing is, time counts, so this fort won't be changing orbits during battles, and getting stuck in interplanetary space pretty means it won't be circling back within the year (at reasonable Far Future or even later PMF settings-we don't have 400g weber-worthy drives but we aren't limited either to milligee nuclear heaters, otherwise we wouldn't have forts :)). This might make a moving fortress design viable. Several fortresses with long range beam weapons could have solar elliptic orbits, coming past Earth in sequence for complete coverage, resupply and such, but won't all be wiped out by a massive unavoidable kinetics waves (you could easily direct a several kiloton dumb wave of kinetics to sweep low orbit of the target planet clean of all spacegoing vessels).

On FTL, we can handwave and technoblabble our way to aky kind of consistent setting, but the usual portal-based FTL can be exploited beyond the forts-envicling-the-exit-point trope. Push in your own fort! If flimsy ships can be vaporized too easily, and there is no limitation on the size or mass of things entering (how else do you have those massive interstellar merchant ships), it can easily degenerate into an attrition war between who can lob the most laser-equipped rocks at each other.

"LEO speed is about 8 km/s. Add 3 km/s & you are almost at escape speed. Vector add 3 km/s to give 8 km/s in a different direction & the new orbit is as 21.6° from the old"

If we're thrusting perpendicularly to direction of travel, adding 3km/s, wouldn't the new absolute velocity be 8.5km/s, raising your orbit after all?
So I was wrong after all.

Tony:
"Shock damage throughout the vessel and spall off the back side of the armor system ought to do a lot of destructive work for me. (Because I'm not shooting a rod-shaped penetrator at the enemy, just a slug.)"

Only possible if the armor is a single thick plate. Even regular whipple shielding can offset spallation, and since it will be incorporated anyway...
I'm not sure how a penetrator rod responds to whipple shielding. It is a continuous length of solid material, and the other end doesn't feel shockwaves or heating until it goes through the target...would it also break up the fluid stream if the whipple shields were of different densities?

KraKon said...

"While propulsion requirements theoretically scale proportionally with mass in space, there are still overhead costs that favor fewer, larger vessels for a given amount of payload."

It could also work the other way around, where massive engines start reaching the upper limits of the weakest components (I once calculated a fusion drive that seemed to require 9 tons of propellant a second for the desired acceleration...will hurt the turbopumps), leading to lower efficiencies. Examples include ginormous pusher plates for a massive Orion drive that don't support the megaton plasma wave too well, NTRs that have problems heating a propellant flow too voluminous, just the structural limits of a given material under a given acceleration!
In other words, it seems drives seem to have an optimal 'band' of sizes for which they are the most efficient. Hand-sized nuclear electric rockets? Moon sized chemical interstellar rocket, anyone?

"tankage mass (volume scales by the third power, surface area by the second),"

Random thing to note: Penetration depth of an impactor rises to its velocity...to the power of 2/3
A 5km/s, 10kg impactor might go through 17cm of supercarbon, a 30km/s, 10kg impactor goes through (30/5)^2/3: 3.3 times deeper. Raises ever more problems with ultra-high-velocity impactors.

"3. Brilliant pebbles were individually very much smaller than laser or particle beam satellites. In terms of launch vehicle requirements, 7,000 of them may in fact have required less lift mass than 200 beam weapon satellites."

And the classic counter would be : how much less? If it costs 20% less, I'm better off using the multi-use, long lived web of laser sats, as it gives me more options then stay dumb/suicide attack on targets, and requires the enemy to invest nearly as much as I did putting up the brilliant pebbles to take out my web of sats.

If they're 3x cheaper, orbital space will be cluttered by thousands of BBODs and flat plate goalkeeper drones.

KraKon said...

Scott!

"If my target has some kind of armor (carbon exotics or aerogels), I'd introduce them to EFPs. 1kg of copper sitting on top of RDX gets a velocity of 6500m/s from the explosion, plus whatever the missile's closing velocity was"

That's something I forgot when comparing LTAWS with chemical missile dumping. The chemical missiles have the option of using up their 10kg warhead to store an EFP...
Initial velocity:5km/s, let's compare a dumb mass 10kg impactor to a 1kg EFP, adding 6.5km/s.
Dumb projectile makes a crater 17cm deep.
EFP makes a crater 13.8cm deep with a more expensive device...oops. Less effective? Maybe not, as the EFP makes a penetrator with a length equal to half its diameter. Set EFP to copper, 1kg is 111cm^3. This make a plate 60cm in radius and 3.9mm in thickness. Target is carbon nanotubes, density 1.6, so penetrative factor is (8.94/1.6)^0.5 or 2.364. The EFP goes through 2.4 times its length, or 70.9cm.

Quite effective! Too bad the hole is 8mm wide...I'm pretty sure ejecta and heating would lead to a thicker (still cm scale) hole but lower total penetration. Given a ratio of 1:30, its hard to find, but I get around 2cm wide for 35.3cm deep.
End result is that you have a more expensive warhead made for easily getting into the insides of the target with ease, but only in a setting where armor is made of carbon nanotubes with 2GPa strength and armor much thicker than 20cm for this to be useful (a PMF setting with steel armor and 3cm thick plates with get torn though by tiny bits of shrapnel, so it is useless to go to the more expensive options).

Secondary problems include cost per unit, igniting the charge with a well placed laser zap, large surface area gives more frequent hits, and small holes mean that if you don't go the whole way through, craters won't cumulate and you'll never get through the shield...

"As I have said repeatedly, I don't see Laserstars as a single-weapon platform."

I have the same vision, but for different reasons. I see the laser as a seperable weapon, that can be installed on another ship if needed. Therefore, any ship, stripped of all other weapon modules, equipped solely with the laser...becomes a laserstar...unlikely. This doesn however make warships in my setting less built around a single weapon system than weapon carriers, with each weapon system an independant modules that can swapped or fitted as needed for the mission.

KraKon said...

Milo:

"There may not be a simple obvious "gun" you can fire at, but you can still just blow up the entire ship, or at least its ammo hold (where unfired missiles are kept), and you can potentially hit the launching mechanism (even if that launching mechanism is a couple of guys with spacesuits)."

Sure, but a typical chemical missile-equipped missile will be no more than a nuclear electric drive, chemical rockets, faceplace, sensors...or not even. The delivery system could be no more than a faceplate with chemical rockets attached to it, with a mothership providing targeting information and a maneouvering system to follow milligee ships. If you shoot at it, all you are doing is obliging it to release projectiles earlier...in the sole hope of realeasing them early enough to get out of the way of the missiles after release. Since the supposed range at which you even detect the drone is within the chemical rockets' interception envelope, I doubt this will be useful. A MUCH more useful tactic is coordinating attacks with an ally (or several) to shoot the flimsy sides of the missiles in the hope of igniting their boosters in the wrong way.

"By how much? A 10% saving (just to make up a number) would probably not be worth the reduced effectiveness of continuous lasers."

Which is a good reason to state that there won't BE any CW lasers as armament, only pulsed lasers that you can choose to set at minimal frequency. Pulsed lasers are essentially modulating how many electrons are emitting photons at a given time. This is very easy with FELs where you time the driver beam pulses (packets of electrons which are pulsed in nature, you can dump more energy into them by pushing them to 0.999c instead of 0.99c but lose frequency), easy with advanced solid state lasers where you release electricity from a capacitor in bursts (within limits of what the laser generator can handle), damn hard with a chemical laser where you have to keep the chemicals burning coninuously to make it work (yes, I know, there are explosive lasers but do you want a bomb trigerring several times a second behind your optics when you're trying to aim at a tiny target a few thousand km away?)

"
Not perfectly. Equipment tends to be more mass-efficient in larger sizes, and often has a minimum viable size (you can't make a watch battery sized nuclear reactor)."

In the PMF setting Rick gave, everything is pretty much proportionate at the scales given.

"But yeah, it'll be fairly close to proportional beyond a certain point."

And up to a certain point?

"But yeah, actual battle is going to be kinda boring. "We have a target incoming." "Okay, so set the computer to start shooting it when it's in range." "Done. ...Okay, it's in range now, the firing mechanism is keeping steady." "Is it blown up yet?" "No." "Are we blown up yet?" "...Shut up." "...How about now?" "SHUT UP!""

Just get the humies off the laserstar! No, really, get an operator back on Earth push the button behind a mug of tea, then go home before the shooting even starts, the battle ends while he's parking his car.

KraKon said...

"Well, if the target is moving even slightly, then a straight line from your position, carved into its armor, will not remain a straight line from your position forever. Beyond a certain point you won't be able to see down the wound channel anymore."

That's why I rotate the armor at 60m/s...it's an arbitrary figure (but enough for a 4GW CW laser) until I find out how far apart do the pulses have to fall on the target surface for them NOT to overlap, reducing damage to that of a single pulse on any given point.
I'll try here (sorry for the even longer post(s)):
Spot size is 1.2cm, pulse energy is 4MJ, crater width is 10cm, so pulsing the laser is viable. The laser is given a frequency of 1kHZ, so we have 500 pulses spaced by 1 millisecond.
The spot has to travel 10cm each millisecond. This gives a velocity of 100m/s; not far from 60m/s. Penetration is 2.5cm per pulse, and a single spin requires 7065 pulses for the craters to start overlapping, meaning my accelstar with 1m of nanotubes/fullerite armor can survive a full 9.4minutes under the ravening beam of death only 1000km away, more if the enemy can't keep the spot within the same 10cm wide band.

HOWEVER...the 15m wide ship is only rotating at 51°/s relative to the target. An F-18 can achieve 720°/s, all without it being a perfectly balanced cylinder. This therefore reasonable to claim that spinning the armor shell exclusively easily gives a relative-to-target velocity of 500km/s...damage goes down when it takes 1.2 minutes for the pulses to even START overlapping each other, meaning the craft can survive at around 47 minutes against an insanely precise opponent.

"Hmm, that too. I hadn't considered that. I'd just been assuming that you can always blast out a crater, but in a really deep hole, it's going to be hard for the molten armor to blow clear of the crater. "

Against a pulsed laser, the pulses are coming in faster than the material can evacuate. What'll happen is that the channel with fill with molten fluid, and vapor/droplets will fountain around the site of impact. These will obstruct the incoming beam, and going through molten material is a lot less efficient that drilling right into armor. For one, shockwaves propagate slower in fluids, the fluid can absorb more heat, and when it is overloaded, it can vaporize to obstruct your beam more. A soltion is to reduce fraquency of the pulses, to allow the ejecta to evacuate before starting over....except that you can't count on hitting the same crater a second time against a moving opponent...

"Actually, now this is making me rethink space stations in general..."

Not really, they might move as fast as regular ships (I did say earlier that I had forts on interplanetary journeys...) but they'd consume a)horrendous amounts of propellant b)stupid amounts of time.

KraKon said...

"Corollary, you can also fortify moons orbiting a planet. You get both the advantages of a large mass of rock and of not needing to shoot through an atmosphere."

Said base better be well dug in as an invader that doesn't refrain from orbital strikes might as well let loose his KKVs at interplanetary speed to hit the base, who cares, there ain't no atmosphere to slow them down.

"(In fact charged particles are the one thing that we can plausibly shield against with near-future technology, using magnetic fields.)"

Except that we'll be using neutral beams, or nothing since lasers are so much better.

"just a ship with a laser on it. "

Ooops. There goes the modular spaceship.

Thuycides:

"Having 7000 independent targets means the enemy needs 7000+ interceptors (or some means of rapidly dealing out death 7000 times) to clear the sky."

Or 7000+ interceptors that weigh an insignificant fraction of the incoming kinetic, if velocities are high enough.

And now Rick (this is getting long):

"I haven't repeated the calculations, but ideally the spot size of your beam and your fire-control pixel size are on the same order. If there is jitter/wander, you can defocus the beam to fill whatever cross section you can effectively aim at. Given sufficient power, you can slowly erode away whatever armor you're zapping."

Except defocusing the beam to cover the whole area of uncertainty means I can't get effective pulsing anymore...The problem with incoming missile who's surface is rotating at 1.5km/s relative to you is that slowly eroding is not an option. Trying to counter LTAWS with cheap goalkeeper drones is not an option either as the LTMs can still accelerate as 1000g when the tanks are neary empty, so it can run circles around foam plates with chemical microthrusters stuck in...

"And, if the laser draws power from your drive reactor, and is designed for the job, there is no inherent reason why you cannot hold the beam on that target, to whatever is the limit of effective aim, for hours. It isn't like your magazine is gonna run low on photons."

Except that kinetics waves come and go on the scales of minutes with LTAWS...maybe I'm deviating here from your post-midfuture to my far future setting, with 5TW mag orion drives and 20kW/kg MHD generators.

KraKon said...

I hope everything went through (and that your read all of it)!

jollyreaper said...


As usual, we can twist around things.


Always. It depends on the flavor you like for your story.

Come to think of it, I built forts like this in Master of Orion. Ships had very poor mobility, major emphasis placed on weapons and shields. No good as an attack fleet but good for defense. They had sufficient mobility to be moved up to vulnerable planets but weren't fast enough to be a rapid reaction force. You weren't going to see an enemy fleet heading to the planet and get your fleet there first, not with these guys.

with a very high velocity. The thing is, time counts, so this fort won't be changing orbits during battles, and getting stuck in interplanetary space pretty


That's when we get back to the idea of strategic and tactical mobility. Something like this would be strategically mobile but not hopping around in the actual fight.

jollyreaper said...


On FTL, we can handwave and technoblabble our way to aky kind of consistent setting, but the usual portal-based FTL can be exploited beyond the forts-envicling-the-exit-point trope. Push in your own fort! If flimsy ships can be vaporized too easily, and there is no limitation on the size or mass of things entering (how else do you have those massive interstellar merchant ships), it can easily degenerate into an attrition war between who can lob the most laser-equipped rocks at each other.



Well, my own setting is the hypersail one. As far as FTL goes, you get sublight but faster than realspace velocities using the sails in stellar gravity wells and go translight out in interstellar space. Without sails, you're limited to tooling about with reaction engines.

The sails are really, really expensive and making a structure FTL-capable is complicated. So there's a real advantage with making forts not FTL-able.



The general rule is that starships need to be big to handle interstellar hyperspace safely. Smaller ships can use hyperspace within the stellar sphere. The smaller the ship, the faster it can go in hyperspace up to a point. Hyperspace combat is about crossing wakes and forcing ships out into realspace. Size matters so heavy warships aren't chasing anyone down but conversely it's also really hard to knock them out of hyperspace. So you need a heavy ship to counter heavy ships.

The kicker is realspace combat. I'm still tweaking the parameters. Lasers are going to be really, really, really good so kinetic attacks just aren't that viable. The nature of FTL doesn't let a ship pop out of hyperspace at really high speeds preserving inertia so you can't drop out right on top of the target and drop rocks going 40km/sec. They can track your approach in hyperspace so when you drop out they can start firing. I want to tweak the character of the lasers so that it's not possible to drop out of hyperspace light-minutes away, fire at where the fort will be in another 8 minutes, and go back into hyperspace before the counter-fire hits you. You're basically limited to having to get close enough to accurately hit the enemy and if he's in range, you're in range, too. Advantage is always to the fort and forts are cheaper than warships so it takes a lot of cash to assemble enough heavy warships for busting forts and they're bristling with armor, emitters, and heft.

jollyreaper said...

It's a stylistic concern -- the harder planets are to crack, the less likely vast sweeping wars will destroy everything. Castle warfare in the middle ages helped preserve the social order. Sure, the enemy could march through and despoil the land but reducing forts was really expensive and when he left the peasants would all come out and the lord of the land would retain all control. Forts and castles could still be reduced but it's a terribly expensive proposition.

Now the one attack method that could work is the big, dumb rock. You land your forces on a chunk of rock and ice out in the oort cloud. Install engines, bury them deep within so that only the bells are pointing out, use the water for reaction mass. Now the question is a) how fast can you get this thing going b) when are the defenders likely to see it coming c) will they need to attack you out there and destroy it? I'm assuming that you know the theoretic burn rate for the defending lasers and have picked a rock that should be able to withstand the best they can do and still hit with a bang. Possibly there's a bursting charge so it's like grapeshot scouring the planet's sphere of all orbital assets and laying waste to the facing side with a meteor shower holocaust. Practicality of all of that depends on the tech assumptions of the setting. Unless there's ridiculous fusion torches, the enemy will see this coming months and months out. But if they can't mount a sally to hit your ships... We're back to the example of castle warfare where knights would head out to through sally ports and set fire to the siege engines of the attackers.

Tony said...

Milo:

"So that just leads to the question of whether you would rather be taking out those launchers (fast enough to keep them from firing, since a launcher which has expended its ammunition is a non-threat) with kinetics or with lasers."

Sorry, but that's not correct. There's no reason a kinetic launcher has to stop being a threat after launch. Does a fighter-bomber stop being a threat after it has dropped half of its bombs? Or all of it's bombs but still retains missiles and guns? Or even just guns?

WRT the lasers vs kinetics issue, you're missing the point -- if the launcher is within laser range, the kinetics have bee on the way for a while. Destroying the launcher before it gets within laser range presupposes some kind of preemptive attack, probably with guided kinetics.

KraKon:

"Only possible if the armor is a single thick plate. Even regular whipple shielding can offset spallation, and since it will be incorporated anyway...
I'm not sure how a penetrator rod responds to whipple shielding. It is a continuous length of solid material, and the other end doesn't feel shockwaves or heating until it goes through the target...would it also break up the fluid stream if the whipple shields were of different densities?"


Whipple shielding only works for very small particles. The ability of the whipple shield to break up incoming particles is a function of the particle mass per unit mass of shield that it encounters. Whipple layers with thicknesses measured in milimeters aren't going to cause projectiles massing kilograms or tens of kilograms to break up before they reach the hull. If you stuff the intervals with absorbent material, that just improves the target's ability to absorb more energy from the projectile, amking the projectile more effective.

BTW, I only brought up long rod penetrators to point out that in space you don't use them, because you don't really care about aerodynamics and the internal ballistics of guns.

Also, something people seem to have missed about lasers, WRT real wolrd applications, is that they have always been intended for relatively large, relatively soft targets. (I forgot this myself until I refreshed my memory with a little research recently.) In SDI terms, lasers were only considered for boost phase intercepts. Mid-course and terminal phase intercept was always a task for guided missiles or projectiles of some type. (Yes, the bomb-pumped x-ray lasers were contemplated for mid-course intercept, but they had to be ridiculously high energy and single-shot for that to work.) The lesson to take away from this is that people who should know didn't think that lasers could reasonably be expected to hold a high enough power spot on a small enough area of application to penetrate any kind of substantial structure.

Thucydides said...

Jollyreaper

Your setting sounds interesting, but the simple "tweak" for preventing rapid "pop out" attacks from hyperspace would be the amount of time it takes to prepare the ship and "rigging" to enter hyperspace again.

If the crew needs more than about 15 minutes to prepare the ship, then once the ship emerges from hyperspace they are pretty much committed to whatever course of action they are performing in inertial space.

KraKon

Back in the 1980's there were investigations as to how small "Brilliant Pebbles" could get, I believe the lowest theoretical size would have been a postage stamp weighing a few grams. The practical lower size limit turned out to be something with enough mass to deliver a good whack of KE to an armoured reentry vehicle. "Genius Dust" really does not cut it as a weapons system.

Jim Baerg said...

KraKon
"If we're thrusting perpendicularly to direction of travel, adding 3km/s, wouldn't the new absolute velocity be 8.5km/s, raising your orbit after all?"

You are thinking of having the final velocity the hypotenuse of a right angle triangle.

If you want the final speed the same as the initial speed but in a different direction the triangle of Vinitial Vfinal & deltaV will be isosceles. So deltaV is not at 90° to Vinitial in this case.

Milo said...

KraKon:

"(yes, I know, there are explosive lasers but do you want a bomb trigerring several times a second behind your optics when you're trying to aim at a tiny target a few thousand km away?)"

Sure! Do I get to operate it manually?


"Against a pulsed laser, the pulses are coming in faster than the material can evacuate."

Not if you're doing it right. If you find that this is happening, then you should slow down your pulses. One millisecond? One centisecond? We're not exactly watching paint dry, here.



Jollyreaper:

"Now the one attack method that could work is the big, dumb rock. You land your forces on a chunk of rock and ice out in the oort cloud. Install engines, bury them deep within so that only the bells are pointing out, use the water for reaction mass."

You forgot to carve it into the shape of a horse.



Tony:

"There's no reason a kinetic launcher has to stop being a threat after launch. Does a fighter-bomber stop being a threat after it has dropped half of its bombs?"

I said "expended its ammunition". Obviously a weapon has expended only part of its ammunition is still a threat.

So another question is how long a weapon can keep firing before running out of ammunition. If you carry 20 missiles and can really rapidly release them all in a single salvo, then I basically have to stop you before you even begin. If you have a machine gun that gradually empties its magazine over five minutes, then that means that disabling your machine gun will be a useful combat objective until five minutes after the fight began. Which means that I need a way of taking it out which has a good chance of working in less than five minutes.

jollyreaper said...

Jollyreaper

Your setting sounds interesting, but the simple "tweak" for preventing rapid "pop out" attacks from hyperspace would be the amount of time it takes to prepare the ship and "rigging" to enter hyperspace again.


There's the question of that and the laser blast itself. The beam would keep a killer punch probably a light-hour out but getting it to hit the target is the trick ... some people here are saying a few light-seconds might be too much to ask for? That's great in my book, anything to keep the engagement range close and exciting. If the attacker could drop out of FTL, lock target and engage with an insta-gib blast within five seconds, then the target would only realistically have five seconds to get a return shot off -- the gap between seeing the ship appear and the gib beam hitting. And if it's not a gib beam but it takes several seconds of lasing to kill a target, that means the attacker's got the advantage. He's shooting at the enemy based on the photons he's seeing the moment he drops from ftl and the enemy has to wait before he can even see what to shoot back at.

If I can force the range to be tighter, it turns more into a gunfight at high noon, both combatants blazing away.

If the crew needs more than about 15 minutes to prepare the ship, then once the ship emerges from hyperspace they are pretty much committed to whatever course of action they are performing in inertial space.


I've been playing around with the idea. The idea is the hyperspace medium can be used like wind. Ship in realspace runs out the sails which are just field projectors. Firing up the hyperfield creates drag and the ship will begin to move in realspace. The captain is trying to negotiate a proper entry into hyperspace with the fields fully engaged. If he handles this in a lubbardly fashion he could destroy his ship. He's also hitting pockets and knuckles of variable density that can damage the ship. Making the translation to hyperspace is murderous on the equipment and taking too long can cause damage. This also precludes the idea of trying to get places by dragging along hyperspace without actually translating -- it would be like using a passenger jet to go cross-town by taxing. Yes, it can be done but wouldn't it be more efficient to actually fly through the air instead?

Coming out of hyperspace, the captain is going to try to match his velocity to his target, try and make orbit. He'll never get it completely right and will have to make final corrections with his reaction engines but the better he does, the less mass he burns. A really lubbardly captain could end up adding hours and hours to the transit time by screwing up his translation. And you can't enter hyperspace within the radius of strong gravity wells so if he really stuffs it there's nothing to do but use the mains to correct his mistake.

Now perhaps there might be a rationale for doing a high-speed pass. Drop the sails while still at a very high velocity, make a firing pass. If you get too damaged, no worries, you're going to be passing out of range. Can't really manage this trick with automated ships since there's no hyper-turing AI's in my setting, just advanced expert systems and they don't have the knack for hyperspace navigation.

I freely admit that the scifi-ish assumptions and handwaves for this setting are mainly about preserving a sense of proper space opera drama while trying to be as gentle to credulity as possible. I do think you can have some good bunker dramas with the "space war as WWIII" scenario but that doesn't fit with the setting I want here.

Scott said...

The nasty thing about explosively-formed penetrators is that they have a velocity 75% of the burn rate of the explosive they use, plus the closing velocity. Also, EFPs don't need to be on a CBDR vector to be able to hit your ship. That complicates your point-defense mechanics tremendously, although it reduces the KE delivered.

Since KE=.5mv^2, if you have an EFP 1/10 the mass of a BBOD, you'd need to roughly triple the closing velocity with the EFP just to break even. However, that varies with the mass of the penetrator. If your BBOD impacts with a mass of 2kg, and the EFP is 1kg of penetrator and 1kg of explosive filler, you are coming out ahead as long as the explosive propulsion is at least 41% of closing velocity.

=====
Where is the formula for determining liniac distance required for a given laser wavelength, anyway?

Tony said...

jollyreaper:

"I freely admit that the scifi-ish assumptions and handwaves for this setting are mainly about preserving a sense of proper space opera drama while trying to be as gentle to credulity as possible. I do think you can have some good bunker dramas with the "space war as WWIII" scenario but that doesn't fit with the setting I want here."

With all due respect, what's "scifi-ish" about any of it? Hyperspace sailing? Really? The reason I read SF is that I don't want to read historical fiction. And computers that can't navigate hyperspace, but humans that can? That was old and lame in the 70s.

You want to do something really different? Make spaceships that look and act like rockets, with FTL drives that aren't magic or simply incredible. That hasn't been done well by a young author in decades.

Luke said...

Tony:

Whipple shielding only works for very small particles. The ability of the whipple shield to break up incoming particles is a function of the particle mass per unit mass of shield that it encounters. Whipple layers with thicknesses measured in milimeters aren't going to cause projectiles massing kilograms or tens of kilograms to break up before they reach the hull.

The basic principle of stand-off armor works for any projectile size, although for larger projectiles you will want a thicker stand-off layer. For hypervelocity impacts, Whipple-style stand-off armor will significantly increase the effectiveness of your armor.

BTW, I only brought up long rod penetrators to point out that in space you don't use them, because you don't really care about aerodynamics and the internal ballistics of guns.

If you need to worry about penetrating armor, a long-rod penetrator will give you greater penetration than any other shape. Going by memory, at a 30:1 aspect ratio the penetration of a tungsten rod exceeds the crater diameter of armor steel at speeds of up to around 80 km/s.

Tony said...

Luke:

"The basic principle of stand-off armor works for any projectile size, although for larger projectiles you will want a thicker stand-off layer. For hypervelocity impacts, Whipple-style stand-off armor will significantly increase the effectiveness of your armor."

You're missing the point. Microparticle armor is not KKV armor. Spaced KKV armor would be mass prohibitive. Any KKV armor would probably be mass prohibitive.

"If you need to worry about penetrating armor, a long-rod penetrator will give you greater penetration than any other shape. Going by memory, at a 30:1 aspect ratio the penetration of a tungsten rod exceeds the crater diameter of armor steel at speeds of up to around 80 km/s."

A long rod would certainly have a better sectional density than a squat cylindrical slug. But unlike a APFSDS round, you can't rely on atmospheric stabilization in space. Keeping the long axis of the projectile and the axis of attack parallel would be a neat trick in a vacuum. Sure, you can spin it for gyrocopic stability, but keeping it balanced under the effects of translation thrusting is going to be a neat trick.

Also, you don't necessarily want to penetrate the target. What if it's unarmored or only microparticle armored? Much of your penetrator could blow right through without dumping energy in the target. That's why even with modern tank guns you still have chemical energy rounds -- they're what you fire at light armored vehicles of various types, because the long rods go right through those like an icepick through tissue paper.

jollyreaper said...

@ Tony concerning hypersail critiques

It's not really aping the sailing tropes like webber. I have an idea I'm trying to capture here. Might work for you, might not.

As for behaving like proper rockets and all, it's hard to use the rocketpunk tropes without also bringing in 50's cheese. Takes work to keep it fresh. You're right that most people don't bother so most ships handle like star wars or star trek.

Avatar should be getting more love on account of their starship. No ftl, laser boost, no artificial gravity? Sure you have space smurfs but come on, look at that ship!

Thucydides said...

It's not the ship.

It.is.the.story

Oh, and the characters, the illogical ecosystem, the "message" being rubbed into your face, etc.etc.

Frankly, I'll take hyperspace sails any day...

Tony said...

jollyreaper:

"@ Tony concerning hypersail critiques

It's not really aping the sailing tropes like webber. I have an idea I'm trying to capture here. Might work for you, might not.

As for behaving like proper rockets and all, it's hard to use the rocketpunk tropes without also bringing in 50's cheese. Takes work to keep it fresh. You're right that most people don't bother so most ships handle like star wars or star trek."


Let me get this straight...you can't make a realistic spaceship without beeing cheesy? Exactly what kind of "cheese" is so unavoidable in presenting something that follows at least a few laws of physics?

As for keeping things "fresh", I was reading stories with hyperspace sailing in the 1970s. So to me they're pure 70s cheese.

And they usually involve technowank. (Though I guess in the case of sailing in hyperspace, that would be pseudo-technowank.) What was so great about 50s and 60s SF, cheesy or not, was that it almost reflexively avoided technowank. A ship had normal space drives, hyperdrive, computers, whatever else, and all the author said about them was that they existed and enough about their effects that the reader understood their purpose. There was no goofing around trying to show your work, which only impresses a very small portion of the audience anyway, while totally boring the rest.

"Avatar should be getting more love on account of their starship. No ftl, laser boost, no artificial gravity? Sure you have space smurfs but come on, look at that ship!"

I have to second (and third, and fourth) Thucydides on this one. The ship was a piece of throwaway technowank that did nothing to rescue a bad, bad story.

jollyreaper said...


Let me get this straight...you can't make a realistic spaceship without beeing cheesy? Exactly what kind of "cheese" is so unavoidable in presenting something that follows at least a few laws of physics?


No, you misunderstand me. It's like trying to do a sword and sorcery fantasy. Lord of the Rings casts a long shadow and most of the cheese associated with the genre comes from the slavish imitations. If you want to do a story that involves swords, dragons and magic, it's going to take a lot of effort to not slide back into being a generic D&D adventure.

Rocketpunk has the additional challenge of trying to remain utterly scrupulous to the limits of technology -- less magic, more hard, so you're constrained. And within those constraints, the audience will be thinking in terms of 50's tropes and any writer will have to work extra hard to do something that isn't just a rehash.

jollyreaper said...

To go back to the fantasy side, I would say that trying to do sword and sorcery realistically would be wiping away the Hollywood veneer. Life is short, brutal, ugly. The food is rotting. There are no flush toilets. Nobody bathes. Sewage flows through the streets. You can smell the filth coming off the page.


Now, should things be that awful? How strong is the magic in this setting? If it's all but extinct and the commoner might live his whole life without seeing even a minor miracle, that's going to be the way of things. But if magic becomes as ubiquitous as tech is today, things could be a whole lot different. Spells to preserve food, potions to cure diseases, people would be living like the elves rather than medieval peasants. So which story do you want to tell? Do you want to talk about elves or about peasants? There's no right or wrong answer here.

jollyreaper said...

As for keeping things "fresh", I was reading stories with hyperspace sailing in the 1970s. So to me they're pure 70s cheese.


Nothing out there is new, just new to younger audiences. I never read those novels but I'm familiar with the early junior spaceman stuff that rocketpunk is seeking to update and modernize. And if something's been out of the limelight for a while, just reviving it can seem like a kind of fresh.

Most of your criticisms seem to boil down to "You're not having fun the right way." There's a difference between doing something poorly and simply not doing it as you would have.

Tony said...

jollyreaper:

"Most of your criticisms seem to boil down to "You're not having fun the right way." There's a difference between doing something poorly and simply not doing it as you would have."

It's more along the lines of what was awful 40 years ago is still awful. And what was good back then is still good. You yourself said there's nothing new. But unlike yourself, I don't think that an otherwise good story can rescue a bad trope, just like a good trope can't rescue a rotten story. Both your story and your tropes have to be convincing to the reader. Hyperspace siling was bad 40 years ago, and it's bad now. Rockets were good forty years ago, and they are good now. That's just the way the cookie crumbles.

f said...

My technology background is not solid enough to properly evaluate the consequence, but how would the laserstar scenario be influenced by weapon-grade advances in optical phased arrays?

Always in my limited understanding of the topic, if we managed to develop a big enough optical phased array, we should be able to have a higly parallel and so damage-resistant system that could be used to generate many weak beams or a single powerful one, and direct those in almost any direction...

From what I know, some limited use is already there in manipulating previously generated beams, and so the phased array would be a lens substitute, but theoretically it should be possible also to use the array directly to generate a beam... or there are some basic limitations I'm not aware of?

Anonymous said...

f; a phased array is a way of amplifying EM energy; obviously it has weapons applications, but also in communications, sensors, and industrial uses (more compact cutting tools springs to mind); however, the same technology can be used to change frequncy as well as increase beam power. You still need optics (i.e. mirrors and/or lenses) to aim and focus the laser. The principle behind phased arrays are that streams of photons can be combined in different ways; you can hetrodyne them to change their frequency; you can phase combine them to increase their amplitude or frequncy; you can even attenuate it or spred out its energy by 'rotating' the phase of the beam. A Phased array is just one way of manipulating the EM energy itself, but does nothing to direct or focus that beam of energy. The two things (phased array and lenses/mirrors) have different effects; the fact that you can use mirrors in a phased array may have confused you. I hope this has helped you.

Ferrell

KraKon said...

Shorter today. Hi f! As usual, we recommend reading previous space warfare posts, and asking specific questions on sfconsim-l!

"Always. It depends on the flavor you like for your story."

I think we can modify any setting to suit to taste as long as we have scales such as FTL, shielding, speculative technologies, unobtaniums that we can slide at will. No-one with a physics book will come up to you and contest your version then!

" I built forts like this in Master of Orion."

Cool! Rather old by now...

"That's when we get back to the idea of strategic and tactical mobility."

Just those two criteria give us four types of ship classes to work with, independently of tech level.
Both tactical and strategic maneouverability (T/S) would be some kind of torch drive, (S) would be forts, (T) would be high thrust interceptors for use in orbit, and no mobility would be planetary defenses...

"Well, my own setting is the hypersail one. As far as FTL goes, you get sublight but faster than realspace velocities using the sails in stellar gravity wells and go translight out in interstellar space. Without sails, you're limited to tooling about with reaction engines."

I quite liked your version of hypersails, consistent and well thought out, but your setting would obtain a big boost in hardness if you didn't allow hypersails to be used in realspace AT ALL. We'd do away with reactionless drives, however inefficient they are, if we can.

KraKon said...

"They can track your approach in hyperspace so when you drop out they can start firing. I want to tweak the character of the lasers so that it's not possible to drop out of hyperspace light-minutes away, fire at where the fort will be in another 8 minutes, and go back into hyperspace before the counter-fire hits you. "

The idea of a non-instantaneous return to hyperspace is the sensible option, but you forgot one thing-to fire a laser, you have to know EXACTLY where the enemy is. In other words, popping out 8 lightminutes out requires you to have 8 minutes of waiting for a firing solution, then another 8 minutes to hit. Your only real advantage is that the opponent will be surprised, and will spend a non-zero amount of time finding you and returning fire.
The end result is that you have 8 minutes, plus time wasted by the surprised enemy, to get back to hyperspace. Make sure this period is a longer than the minimum, by a few minutes at least, so the attacker won't escape with a only a few bruises and scratches.

" a) how fast can you get this thing going b) when are the defenders likely to see it coming c) will they need to attack you out there and destroy it? "

You're likely to get it going up to twice the exhaust velocity of the drive installed (nobody has bothered clearing this out for me on sfconsim-l, but the maximal velocity of a spacecraft is twice the drive's exhaust velocity, right? After all, drive efficiency falls to zero when your going 2.5x its exhaust velocity, and is 100% when going at exhaust velocity=travel velocity relative to jet).
If you are using some kind of nuclear thermal drive to profit from all the remass surrounding you, its going to be up to 20km/s. If you're using a nuclear electric drive, it can be anything you want within the power levels you have.
To b, I'd say REALLY FAR OUT. The Asteroid Fort may be cold on the surface, but its MASSIVE (or at least very large to be useful) and has a very hot jet pushing it at a trajectory set for months; you may only not be able to actually target it from far out.
To c, the answer is mixed. They will start lasing you the moment they detect you, but the damage will be low and significant only over time. As you get closer, missiles will come, with very high velocity kinetic warheads. As you come in closer, the danger increases. You will be vulnerable to high velocity dumb rounds (this Asteroid Fort presumably can't dodge anything) fired by coilguns and nuclear weapons that are designed to mess up whatever you dug in through shockwaves: this will be a deadly effective tactic.

"Possibly there's a bursting charge so it's like grapeshot scouring the planet's sphere of all orbital assets and laying waste to the facing side with a meteor shower holocaust."

Unlikely. Such a charge would need enough energy to obliterate the asteroid . It would also destroy anything installed on it, reducing it to some kind of manned kamikaze missile (SHOUT OUT!). Also, if such an explosive charge could be delivered, the defenders would have done it much earlier.

KraKon said...

"We're back to the example of castle warfare where knights would head out to through sally ports and set fire to the siege engines of the attackers."

We've been in a castle-warfare type of mentality ever since the attackers refrained from slagging. The defenders just have so many huge advantages over the attackers; ever more so in space. Massive one shot-kill weapons don't change the balance-they just reduce a successful defense to a Pyrric victory, attacker obliterated, defender badly damaged, but who cares, the attacker won't be sending any more fleets for a good amount of time.

"Whipple shielding only works for very small particles. The ability of the whipple shield to break up incoming particles is a function of the particle mass per unit mass of shield that it encounters. "

Perfect. Except that this Whipple shielding is for military protection, and it is defending from weapons. Therefore, the millimeter-thick design is useless against something other than what it was designed for initially-defending from micrometeorites. When you are trying to defend from incoming kinetics, its a whole different matter! Of course military Whipple shields are much thicker (in the several cm range). I have 25 layers of 1cm thick carbon nanotube armor, seperated by 1cm of an isolating material.
The regular penetrator rod is a 1m long rod of iron, ie around 6 times denser than the armor material. However, all I know is that shockwaves travel at around 5km/s in iron, and at velocities above 5km/s this means that the shockwave generated by impact won't reach the other end of the rod before it goes right into the target. Since shattering the rod necessitates shockwaves to bounce back and forth inside the projectiles...this method probably won't work. MAYBE the Whipple shielding will reduce the depth ratio of the crater formed, as material accumulates more easily in front of the impact shockwave+advancing battering ram of molten slag, making a wider but shorter hole.

"f you stuff the intervals with absorbent material, that just improves the target's ability to absorb more energy from the projectile, amking the projectile more effective."

You'll absord the entire energy of the projectile anyhow, because it has nowhere else to go. Therefore, better absorbing the projectile's energy through isolating material means it gets stopped earlier on, rather than deep inside your ship.

"Back in the 1980's there were investigations as to how small "Brilliant Pebbles" could get, I believe the lowest theoretical size would have been a postage stamp weighing a few grams. The practical lower size limit turned out to be something with enough mass to deliver a good whack of KE to an armoured reentry vehicle."

I'm confused now. Are brilliant pebbles the BBODs, or are they guided frag?
Eitherway, I am highly doubtful of the efficiency of a system designed to evenly distribute thousands of miniature KKVs, and expect them to both stationkeep with miniature chemical thrusters, spread evenly enough on their own and stabilize their orbit after their release, intercept any kind of enemy that isn't trying to plough through them, and most importantly, not interfere with outgoing/ingoing traffic.

KraKon said...

"If you want the final speed the same as the initial speed but in a different direction the triangle of Vinitial Vfinal & deltaV will be isosceles. So deltaV is not at 90° to Vinitial in this case."

Ah.
Good thing in my setting either the nuclear thermal tugs have high enough thrust not to care, or the accelstar is in a combat situation and a handy nuclear charge can move it around when needed.

"Sure! Do I get to operate it manually?"

Make sure you don't have any coffee or energizing products beforehand!

"One millisecond? One centisecond? We're not exactly watching paint dry, here."

I'll ask Luke about how fast molten material is supposed to leave the hole when is cannot be perfectly vaporized, and when there's a cloud of vapour between the crater and the beam.
Wait. Forgot a thing. Carbon sublimated, doesn't melt. That means all I'll have is high pressured jets of carbon gas, NOT the much slower molten metal. Oh well.

" Yes, it can be done but wouldn't it be more efficient to actually fly through the air instead? "

EXCEPT THAT YOURE VIOLATING THE LAWS OF SCIFI HARDNESS WITH A REACTIONLESS DRIVE, even if you made it ineffective and degrading to the equipment.

KraKon said...

"With all due respect, what's "scifi-ish" about any of it? Hyperspace sailing? Really? The reason I read SF is that I don't want to read historical fiction. And computers that can't navigate hyperspace, but humans that can? That was old and lame in the 70s."

It is very easy to have a plausible situation that involves hundreds of factors involved in hyperspace entry/exit, that a really fast computer would still bog down in trying to sort out and optimize the transit, while a human navigator could feel a 'trend' and go with gut feelings...well informed gut feeling that is. Tony, with soft sf tropes, we can have anything we want to have, and retcon stuff that violate internal consistency. We ain't obeying physical laws here...

"You want to do something really different? Make spaceships that look and act like rockets, with FTL drives that aren't magic or simply incredible."

Actually, it is better to have a hybrid (in my opinion). Obey physics where you expect them to be obeyed (for the hard sf stamp) and go wild but consistent on anything that isn't defined by laws of physics. For example, I prefer NO explanation and a set of rules for an FTL drive rather a technoblabble wall of text exposing quantum theory hypothetical FTL methods incorrectly. That way we get plausibility (because we kept the setting hard there and there) and the fun (because we're not stuck to the overused scenarios and world that VERY hard sf limits us to, ie Earth orbit, Next Sunday AD stuff or a teeny weeny lunar base that we're trying to contrive reasons for it to revolt).

"That hasn't been done well by a young author in decades."

Because a young author understandably seeks an audience for his work the moment the book hits the shelf (or the Net), meaning the flashy cover with visible laser beams and barrel rolling space fighters is a tempting choice. Heck even Weber with his detail and mathematics fell for the space fighter thing.

"Going by memory, at a 30:1 aspect ratio the penetration of a tungsten rod exceeds the crater diameter of armor steel at speeds of up to around 80 km/s."

?
What does that mean? How is the velocity of tungsten and the crater diameter of armor steel exceeded at 80km/s?

At high velocities (around 30-100km/s) you can use the fluid model, meaning rod length*square of penetrator density over armor density=crater depth. For an impactor, you divide the projectile's kinetic energy by 3x the strength of the armor, and you find the volume of the crater. Switch between the two models for what suits you best. It usually goes:
0-20km/s: Dense, shorter penetrators
20-100km/s: Less dense, longer penetrators for the fluid model
100km/s+: Impactors. Crater sizes are just so big.
150km/s+: Streams of impactors because the initial impacts leave ionized plasma that can be diverted using magnetic fields.
Crazy velocities: Genius Dust, if there ain't no plasma screen, decelerate a bit and use a nuclear penetrartion aid otherwise (creates a big hole in the smoke screen, stream of impactors unleashes hell afterwards).

KraKon said...

"You're missing the point. Microparticle armor is not KKV armor. Spaced KKV armor would be mass prohibitive. Any KKV armor would probably be mass prohibitive."

Yes, that's why I had to distinguish between Rick's PMF setting and my FF setting, where nuclear pulse propulsion makes armor cost in mass less of an issue.

"Sure, you can spin it for gyrocopic stability, but keeping it balanced under the effects of translation thrusting is going to be a neat trick."

There won't be any translation thrusting issues with the rod. It will be mounted in a bundle on top of a missile bus. The missile bus handles translational thrusting until 100km or less (depending on closing velocity) from impact. Then it releases then without release charges, it just aims and lets them drift apart. 3-4 seconds later, they hit the target; not enough for them to hit diagonally to any significant degree.

"Also, you don't necessarily want to penetrate the target. What if it's unarmored or only microparticle armored?"

You're right! Looking at the laserstar image on top of this image (no, not that one, the higher up blog title image), I notice that most of the ship is light and with low cross-sectional area. You have the hab with very thin bulk heads, you have the flimsy struss with very low chance that kinetics will hit anything solid going through it, the propellant tanks are thin tanks, and we have the drive, which is dense but pretty small. Not much stuff that needs penetrating!

"It's not really aping the sailing tropes like webber. I have an idea I'm trying to capture here. Might work for you, might not."

I don't recognize it as anything else, so it is original enough for a reader with a layman's knowledge of sf.

"Avatar should be getting more love on account of their starship. No ftl, laser boost, no artificial gravity? Sure you have space smurfs but come on, look at that ship!"

Yeah, and the film concentrated on the space smurfs and left the spaceship with 10S of onscreen time.

"The ship was a piece of throwaway technowank that did nothing to rescue a bad, bad story."

I prefer the film Suckerpunch. Gave up on the plot, gave it all as a visual treat and didn't ask for more (earning it the nickname of Suckerpunched).

Rick said...

The lesson to take away from this is that people who should know didn't think that lasers could reasonably be expected to hold a high enough power spot on a small enough area of application to penetrate any kind of substantial structure.

Within the 1980s state of the art, or at any rate what people in the 1980s thought could be achieved after a few years of throwing beaucoup money at the problem.

Rick said...

wiping away the Hollywood veneer. Life is short, brutal, ugly. The food is rotting. There are no flush toilets. Nobody bathes. Sewage flows through the streets. You can smell the filth coming off the page.

I gotta say, that stuff would just grump me as another Hollywood variant. In fact, most modern medievalesque Hollywood has that look. No more realistic than the old look, and uglier.

Rick said...

I share Thucydides' and Tony' grump about Avatar. A cool looking spaceship was not enough to make me spend money on "Dances with Blue Elves." A few minutes of the ship, two hours of my life I'd never get back.


As for the actual topic of this discussion, criminy jeez, my head explodes just scrolling through some of the comments upthread! I'll try to read it through and then make a useful comment!

On hyperspace sailing, I would call it a near science-fantasy trope, but within that subgenre a perfectly legit one.

In strict logic, of course, any FTL is demi-fantasy, but there is a matter of how onstage it is.

A jump point FTL can be pretty much offstage - ships get to the jump point using Realistic [TM] normal space drives, handwave their way through, and go on their way. But if you're 'sailing,' or doing anything in particular in FTL beyond twiddling your thumbs, it forces the FTL onstage, and makes the story action that much more quasi-fantasy.

Does that make sense, at least as an arbitrary stylistic judgment?

Raymond said...

Krakon:

"...but the maximal velocity of a spacecraft is twice the drive's exhaust velocity, right?"

Nope. There is no maximal velocity (and relative to what?), but there are practical limits based on tankage mass if nothing else. A delta-v of 2x Ve requires a mass ratio of ~7.4, which is easily doable for rockets, but pushing it past ~10 is unlikely (which is why staging is important). Theoretically, delta-v has no maximum - but the mass ratio increases exponentially.

jollyreaper said...


I quite liked your version of hypersails, consistent and well thought out, but your setting would obtain a big boost in hardness if you didn't allow hypersails to be used in realspace AT ALL. We'd do away with reactionless drives, however inefficient they are, if we can.


The realspace use is just to make getting into hyperspace more exciting. You're cranking up to speed and have to worry about tearing the sails off. You're trying to make translation before you burn out the generators and if you're really unlucky, you tear the damn sails off. If you survive that, you're off on a useless vector and are in for a long burn on the mains so you can try limping back home in realspace for refitting.

One tactic that would be plausible that I'm on the fence on is a kind of skip-bombing. If you can run right on the edge of translation and dip your ship back into realspace you could drop off a kinetic weapon or fire a laser and then skip back into hyperspace before the return fire. Doesn't quite fit with the flavor I want. I'd compare it to the recent Galactica show with multi-jumping. Up to a certain point they'd portrayed jumps as something that took a while to pull off so battles were defined by ships jumping in, ships jumping out, flying conventionally to make attacks but NOT tactical jumps in the middle of combat. You don't get a basestar appear a thousand miles off and then jump again and now it's up your nose firing missiles. But then they had the Galactica do the multi-jump above that planet. While that looked cool, it completely ruined prior continuity. Could the ship always do that? Why not do so in these earlier situations? You're right back in comic book territory where writers can't keep track of how many powers Superman has and the only way to preserve drama is to forget powers that would resolve the plot complication in short order.

jollyreaper said...


Unlikely. Such a charge would need enough energy to obliterate the asteroid . It would also destroy anything installed on it, reducing it to some kind of manned kamikaze missile (SHOUT OUT!). Also, if such an explosive charge could be delivered, the defenders would have done it much earlier.


The burster charge would be installed by the attackers -- shatter the rock at optimum range. Too many incoming targets to engage and you could always have a few active seekers hiding in there taking advantage of the distraction.

The end result is that you have 8 minutes, plus time wasted by the surprised enemy, to get back to hyperspace. Make sure this period is a longer than the minimum, by a few minutes at least, so the attacker won't escape with a only a few bruises and scratches.


Yeah. Basically the attacker has the advantage of knowing where to look and is inside the defender's light cone. His own light cone starts the moment he jumps in and won't even be known to the enemy before it reaches him. Well, if the enemy has his hyperspace sensors up he'll know the general bearing and range of the target but that won't be enough for a firing solution until he's got photons in his telescopes.

jollyreaper said...


It is very easy to have a plausible situation that involves hundreds of factors involved in hyperspace entry/exit, that a really fast computer would still bog down in trying to sort out and optimize the transit, while a human navigator could feel a 'trend' and go with gut feelings...well informed gut feeling that is. Tony, with soft sf tropes, we can have anything we want to have, and retcon stuff that violate internal consistency. We ain't obeying physical laws here...


from the background I worked up:

The lowest clines of hyperspace might move at a fair clip against realspace by the lights of planet-dwellers but they are far too slow for useful interstellar travel. A starfarer must dare the higher clines to make real progress. The currents and eddies are fiercer, density waves propagating through the hyperspace medium. Great storms and colliding currents can run for light-years and can never be challenged, only skirted.

So, given these conditions, how does one guide a starship? Like a spider on her web, the starship’s hypersails are sensitive to ripples traveling across hyperspace. There are swells and waves and echoes, vibrations that strum across the clines. The ship’s plot constructs a model of hyperspace surrounding the ship and feeds it to the operator as a kind of synesthesia. While all subjects will see a kind of visual abstraction of the ship against local space with the ripples of space as a multicolor fog, the brain will interpret the rest of the data as a mix of sound, taste, smell, touch, temperature, balance, and pseudosensory phenomena that are hard to even describe in words. No two people ever see hyperspace the same way and those who have an intuitive grasp for it are among the most prized of helmsmen and navigators.


A starship is not controlled by people sitting at consoles poking buttons. The ship’s computer and servitors takes care of the minutia of housekeeping and basic maintenance. The computer can even plot a course through realspace using the reaction engines for propulsion. What it cannot do in the least is navigate through hyperspace. Machine intelligences are adept at mastering things that can be reduced to a science but are hopeless at mastering an art.

endquote

Is this a really big author fiat handwave? And how, with a giant foam #1 finger. But I think it's along the lines of the Butlerian Jihad, allowable in a setting if provided with proper support. I mean hell, look at psychohistory with Asimov. Complete, 100% bunk and he admits it on the spot. He's not saying "I think this is real," he's saying "Imagine the consequences if it were."

jollyreaper said...


I gotta say, that stuff would just grump me as another Hollywood variant. In fact, most modern medievalesque Hollywood has that look. No more realistic than the old look, and uglier.


So what we're talking here is the Roy Rogers western approach or the Deadwood approach. Clean-scrubbed singing cowboys you could invite to the church supper or boozin', cursin', whorin' monsters who look like they'd be more at home with the Mongol Horde. Accurate or trying too hard?

Based on everything I read, the filthy and ugly parts seem fairly accurate. The only thing that would be hammed up is the amount of action going on. The military in wartime is described as 99% boredom, 1% terror. So anything showing 50% filth and 50% fighting is probably sticking in too much action. Most cops, even in bad areas, they never fire their pistols once in the line of duty but cop shows would make you think they get in three firefights before they hit the donut shop.

What would you call realistic?

jollyreaper said...


A jump point FTL can be pretty much offstage - ships get to the jump point using Realistic [TM] normal space drives, handwave their way through, and go on their way. But if you're 'sailing,' or doing anything in particular in FTL beyond twiddling your thumbs, it forces the FTL onstage, and makes the story action that much more quasi-fantasy.

Does that make sense, at least as an arbitrary stylistic judgment?


It's perfectly fine. As a rule I tend to agree that the less explanation the better when directly bashing physics over the head because everything you say gives you more opportunity to be wrong. That's why I prefer fantasy stories stick with self-consistent magic for explaining as much of the weird stuff as possible. The moment you start trying to explain vampires and werewolves and shapeshifting superhuman powers as a virus the head starts thunking the desk. You risk getting into "40 Year Old Virgin" territory when you move from the imaginary to describing something your audience would have experience with and they realize you have no idea what you're talking about.

As far as genres go, I can appreciate everything from fantasy to science-fantasy to SF all over the Mohs scale. Just do something interesting and do it well.

Tony said...

Re: jollyreaper

This is where you run yourself into all kinds of trouble with technically sophisticated readers. Why and how does hyperspace have "clines"? Why and how does it have correspondence with normal space such that its dynamic structures can be measured in normal space metrics like light years? If it has such one-to-one correspondence, by what mechanism(s) can a ship attain an FTL speed of advance? Why, if the ship's plot can construct a sensible model of hyperspace, and feed it through electromagnetic means to the pilot, can't the plot be programmed to use the data itself to shape a course?

Standard models of hyperspace require only a single handwave -- you hit the button and some magic happens to change your coordinates. Even the simplest models of hyperspace sailing are five-axis handwaves with ten fingers on each hand.

Milo said...

Jollyreaper:

"Now, should things be that awful?"

I hope not, because it wasn't even without magic.


"Life is short, brutal, ugly."

Yes, life was more dangerous than it is now, but once you made it to adulthood you'd have a pretty good chance of reaching (what we consider) old age.

Also, most fantasy stories are told from the perspective of priviledged people (knights of noble birth or at least high station, learned wizards with well-stocked towers, etc.), who tended to have it easier than average people. Until they went to war, anyway, but that's still unpleasant even today.


"The food is rotting."

They had salt. I'm sure curing food takes more effort than just stuffing it in a refridgerator, but that's pre-industrial life for you - you have to do stuff by hand.


"There are no flush toilets."

But there are chamber pots. You just have to take a minute to get up and carry it out of the house by hand, lazybones.

Better yet, if you're a peasant, use it as fertilizer! Why waste it?

...Hmm. And apparantly, flush toilets (of a sort) existed since the 31st century BC.


"Nobody bathes."

This wasn't due to a lack of baths - the Romans had sewers, and people even before that knew to use natural springs.

What they didn't have is indoors plumbing in private homes (except for some rich people). The Catholic church decided that public bathing is indecent and so tried to stamp it out (latching on, as an excuse, to psuedoscientific theories of the time which believed that bathing was unhealthy).

Nearly everyone except the Europeans still bathed. (Christian Europeans, that is - the Vikings made a point of bathing in hot springs once a week.) And it's not like they never gave it a try, either.


"Sewage flows through the streets."

That was a Roman practice. Not a medieval one.


"You can smell the filth coming off the page."

I hope not. If I can, I'm switching to a different printer.


"So which story do you want to tell? Do you want to talk about elves or about peasants? There's no right or wrong answer here."

Personally I think the Islamic Golden Age is a good source of inspiration for a "medieval-ish" flavored culture that nonetheless has many of the conveniences (and fancy trinkets made by eccentric inventors) that fantasy authors seem to like to have in their world. You can give them European fashion tastes if you really want...



Bottom line: Contemporary writers were usually more interested in writing about heroics than whining about how filthy their life is. Why should you be any different?

Milo said...

KraKon:

"Wait. Forgot a thing. Carbon sublimated, doesn't melt. That means all I'll have is high pressured jets of carbon gas, NOT the much slower molten metal. Oh well."

If melting materials actually have a significant advantage in laser resistance over sublimating ones, then people will use something that melts rather than carbon, despite carbon's other beneficial properties. (Does aerogel melt?)


Jollyreaper:

"One tactic that would be plausible that I'm on the fence on is a kind of skip-bombing. If you can run right on the edge of translation and dip your ship back into realspace you could drop off a kinetic weapon or fire a laser and then skip back into hyperspace before the return fire. Doesn't quite fit with the flavor I want."

If someone tried that on me, I would probably try to chase them into hyperspace, rather than staying in realspace where I'm a sitting duck. You can only skip to and from hyperspace that casually if there's no-one currently in hyperspace to make your life hard.


"The military in wartime is described as 99% boredom, 1% terror."

The ultimate problem with these stories is that many people are stuck in the video game model of combat, where your glorious hero carves through hundreds or thousands of mooks by the time the story is over.

In fact, even if everyone fights to the death, it stands to reason that an average soldier will be involved in exactly two fights - one which he wins and one which he loses.

The rest of the story will be about tactical maneuvering before meeting the enemy, or will be told from someone else's perspective. In reality, a war is going to have no single unit that is present in every major battle right up until the climactic showdown - every bit of the war is fought by someone else.

KraKon said...

Milo:

Melting does have the advantage of clogging up the hole you're trying to drill, and sublimating carbon clears out the hole much quicker, meaning faster drilling (aerogel doesn't melt, it sublimates. But why do people keep on mentioning it as anti-laser armor?!). HOWEVER, stuff that melts also has far less resistance to lasers than carbon (yes, even that boron stuff), probably offsetting whatever advantages and clogging has by a large margin....

Drive efficiency-I war wrong.
The function is E: 2X/(1+X²) where E is efficiency (after internal losses) X is exhaust velocity over current velocity (relative to anything). Found out it never equals zero, so I can always accelerate. More points for low eV, low dV but high thrust drives...

Raymond said...

Krakon:

"Drive efficiency-I war wrong.
The function is E: 2X/(1+X²) where E is efficiency (after internal losses) X is exhaust velocity over current velocity (relative to anything). Found out it never equals zero, so I can always accelerate. More points for low eV, low dV but high thrust drives..."


No points for low eV drives, actually. Yeah, you can always burn, and always get something, but with a low exhaust velocity the mass ratios become prohibitive rather quickly.

Efficiency's just not the big concern - ranks at best third, after mass ratio and exhaust velocity (the only two factors in overall delta-v), or possibly fourth, after burn time (which is a large factor once you get into the high-exhaust-velocity drives). If you're looking for some hard numbers, the minimum energy for a given delta-v is found at ve = 0.6275Δv (as per Teh Wiki Page, and given a fixed ve), which gives a mass ratio of 4.92. Above that, you spend additional energy accelerating the larger initial mass, and your efficiency goes back down. It should also be noted that a mass ratio of around 5 is usually where staging is done, subject to modification for nozzle efficiency at different altitudes in the case of surface-to-orbit rockets.

Raymond said...

jollyreaper:

"Is this a really big author fiat handwave? And how, with a giant foam #1 finger. But I think it's along the lines of the Butlerian Jihad, allowable in a setting if provided with proper support. I mean hell, look at psychohistory with Asimov. Complete, 100% bunk and he admits it on the spot. He's not saying 'I think this is real,' he's saying 'Imagine the consequences if it were.'"

A few things:

- Asimov, in one of his later essays, mentioned some (current, at the time) research regarding predicting human behavior in groups using fluid dynamics. He then commented that instead of feeling a little vindicated over the underpinnings of psychohistory, he felt disappointed, since the required sample size was so much lower than he thought would be required. So no, not exactly bunk, and he was (in a way) closer to the mark on psychohistory than he was on robotics.

- The Butlerian Jihad wasn't just author fiat nor handwaving; it's central to the setting, and crucial to the plot in a distant way (the removal of computerized control for FTL required the spice and the navigators to compensate, which led to the very power structure at the first book's center).

- The thing about big handwaves and author fiats is that they should matter if you describe them at length. Here I'm at least somewhat in agreement with Tony - if you need FTL, but the specifics don't matter to the story, don't bother describing it. Use the Big Red Button Of Moving. No point in coming up with elaborate schemes for handwavium generators just for flavor.

- I'm really, really not a fan of hypersail-esque FTL methods, because I like my space to act like space. One possible exception is the Warp, since if 40k does anything right, it's a coherent picture of the Imperium as natural consequence of the nature of the Warp.

- There's also absolutely nothing about rocketry (chemfuel, fusion, whatever-you-please) which requires adherence to 50s-era tropes. In fact, somewhat the opposite, since so few of those stories actually bothered with rockets, and went straight to torch drives.

Thucydides said...

"Brilliant Pebbles" were designed to patrol in an unpowered orbit encased in a lifejacket. Minimum effective mass was calculated to be in the neighbourhood of 2.5 Kg but a practical Brilliant Pebble would probably be closer to 20kg to include the fuel, intercept motor, communications systems and batteries and so on.

Since they were in LEO, they were already moving at a considerable velocity, hence the amount of mass needed wasn't all that much.

In the near future, if competing Earth powers were involved in space combat, they would probably have some version of brilliant pebbles attacking each other's space assets (including enemy brilliant pebbles). Brilliant pebbles technology can also be used in ASATs as well. For plausible/implausible midfuture combat, small KKVs will be boosted and then dispersed at long range from the target.

jollyreaper said...


This is where you run yourself into all kinds of trouble with technically sophisticated readers. Why and how does hyperspace have "clines"?


That gets down to the fundamental questions of the universe. Why do we have the four fundamental forces? Why are their values what they are? If they were any different, we might not have seen stars form, we could have an empty, cold universe of clumped hydrogen with traces of helium. We get into the anthropic principle and chin-scratching.

From the perspective of the characters, it's this way and they're like a 14th century mariner speculating about the ocean. Where do the currents come from? what of the waves? What makes the wind? They're too far off from understanding that it's all energy ultimately derived from the sun, it's all a matter of solar heating and areas of higher energy moving to areas of lower energy.

As an author speculation I'd say it would be something along those lines.

Why and how does it have correspondence with normal space such that its dynamic structures can be measured in normal space metrics like light years? If


That's just a translation. You see where you were when you went into hyperspace, see where you are when you come out, work out how fast your transit was at that point. Guesstimating velocity while in hyperpace can be tricky and there's always uncertainties.

it has such one-to-one correspondence, by what mechanism(s) can a ship attain an FTL speed of advance?


Physics beyond the here and now. You generate a hyperfield, it picks up the tug of hyperspace. It drags against the hyperspace medium. You can't play with it on a lab bench on a planet because you're within the planet's hypershadow. Get on a station outside of the shadow and you can build a little field generator and put power into it and measure the tug. If you pump enough power into the hyperfield, it will get yanked into hyperspace in a messy and uncontrolled fashion, a portion of the mass of the generator hardware converted directly to energy. Hard gamma rays for everyone.

With a proper ship and a navigator and helmsman melded with the sensorium, the hypersail ship can successfully translate to hyperspace.

jollyreaper said...

Why, if the ship's plot can construct a sensible model of hyperspace, and feed it through electromagnetic means to the pilot, can't the plot be programmed to use the data itself to shape a course?


There was an old scifi story from the 50's set in the 90's involving the future cold war. Rocket planes would be scrambled to intercept suspicious suborbital flights. Given the setting there was a chance it could be a civilian plane or an ICBM. Everything in the ship is automated. The whole story goes on about how useless the human is for most of the flight. Ground control computers handle the launch, flight control computers shape the course, targeting is handled by the targeting computers. The human's ONLY purpose is pressing a yes/no button. Do we shoot or not? Because despite all the power of the computation involved, nobody could figure out how to build a computer good enough to make that decision successfully. And this same logic is behind all of our arguments about why humans are kept in the loop in our space settings.

Now the question of what calls for a human keeps getting defined upwards. I just set an appointment for some blood tests with a sophisticated voice-commanded computer. There's a whole conversation as it talks you through picking a location, time, what work you need, etc. No pressing numbers, all voice driven. Over crappy phone audio! But we still need a human to draw the blood. For now. And Google's already showing the shortcomings of doctors. Patients are having to search for their own symptoms to find out what they have because most doctors can't bother to give them the time of day. It's a very short step from googling by keyboard to just speaking to the computer to describe your symptoms and getting back a short list of possible problems.

So, how long until the computer can figure out hyperspace navigation? It can't. The nature of hyperspace falls into that weird kind of temperamental territory that's like dealing with people, it just doesn't lend itself to deterministic modeling. Hyperspace is a dimension apart from our own operating under its own rules and the sorts of things we've come to expect from physics and modeling this reality just don't fly over there.

jollyreaper said...

Now, in our reality, I think there's a good chance we can create turing-passing machines to very high degrees, AI's that can write the most heartfelt novel, that can carry on a romantic correspondance online, who aren't just faking sophoncy but are truly alive and go beyond us. So in that case, for a machine that can embody every aspect of the human psyche and surpass it, hyperspace would pose no challenge. BUT if we stick with my fiat that there's expert systems but no human-equivalent or transhuman AI, then hyperspace lies at the very spot that differentiates man from machine. No human could fly a fighter better than a machine, could stitch a better seam, throw a more perfect baseball but no machine could write a meaningful poem or connect with another human on an emotional level. Humans might personify them but the machines, no matter how sophisticated, are soulless, without will or consciousness. They serve us because they are programmed to and could no more do otherwise than a table could rebel and try to be a bicycle.

Standard models of hyperspace require only a single handwave -- you hit the button and some magic happens to change your coordinates. Even the simplest models of hyperspace sailing are five-axis handwaves with ten fingers on each hand.

That's what makes it fun. Or maddening, depending on your bent. It's a matter of taste. For example, some people LURVE Tom Clancy exposition, going into all the little details. The man didn't fire a gun. He pulled the trigger of an HK-45 which brought the hammer down on a rimfire .45 hollowpoint the weapon was especially chambered for; the .8 grain powder detonated supersonically and the bullet was propelled down the 12 inch barrel and blah blah blah flew through the air punched through shirt and flesh and did this and that to organs. (I'm not a gunfondler so I just threw terms together up there.) Point is, there's going to be people who love all that and there's going to be people who hate it. There's no good or bad here, simply a matter of taste. If Clancy's writing for a gun-fondler audience, criticizing him for going into too much detail is missing the point. Someone telling him he got the terminology wrong, THAT is a valid criticism.


Now the question of what calls for a human keeps getting defined upwards. I just set an appointment for some blood tests with a sophisticated voice-commanded computer. There's a whole conversation as it talks you through picking a location, time, what work you need, etc. No pressing numbers, all voice driven. Over crappy phone audio! But we still need a human to draw the blood. For now. And Google's already showing the shortcomings of doctors. Patients are having to search for their own symptoms to find out what they have because most doctors can't bother to give them the time of day. It's a very short step from googling by keyboard to just speaking to the computer to describe your symptoms and getting back a short list of possible problems.

So, how long until the computer can figure out hyperspace navigation? It can't. The nature of hyperspace falls into that weird kind of temperamental territory that's like dealing with people, it just doesn't lend itself to deterministic modeling. Hyperspace is a dimension apart from our own operating under its own rules and the sorts of things we've come to expect from physics and modeling this reality just don't fly over there.

jollyreaper said...


- I'm really, really not a fan of hypersail-esque FTL methods, because I like my space to act like space. One possible exception is the Warp, since if 40k does anything right, it's a coherent picture of the Imperium as natural consequence of the nature of the Warp.


The descriptions I've used of the sails on this blog I've kept on the agnostic side, eschewing the details of any particular setting. The original idea I'd had actually ended up recreating the Warhammer Warp before I'd ever heard of it. That's the problem with scifi, you get a bunch of geeks ruminating over the same ideas and reading the same writers, they're bound to bang things together and simultaneously invent new things.

The original idea I'd had for the hyperspace and hypersails was the fear of the great unknown that mariners dealt with in the distant past with inaccurate maps, superstition, and imaginary monsters. I thought "What if those things were real?" and immediately went to Lovecraft. From there it made sense to go with the idea of treacherous hyperspace with cosmic monsters and physics that worked contrary to what we're comfortable with. Lovecraft was a huge fan of that sort of thing -- it's not the things that go bump in the night that drive intelligent men crazy, it's the stuff that doesn't behave as stuff ought to, stuff with no respect for proper physics!

I was real proud of the ideas I'd come up with until I found out Warhammer stole 'em from me by doing 'em first. lol

jollyreaper said...


Bottom line: Contemporary writers were usually more interested in writing about heroics than whining about how filthy their life is. Why should you be any different?


It's a question of truism. A western might not dwell on how much it sucked to be a chinaman slaving on the railroad but it's important to note that a revolver as damned expensive, not the sort of thing you just nipped down to the store to buy, and trying to make a living homesteading was not going to be all lounging and idyl.

I would try to make things as accurate as historical research allows for. If I'm trying to create an idealized society I might pick the Muslims of that period but if I'm trying to find some nasty aggressors who are willing to travel great distances to kill people for God, gold and glory, the Europeans are a good model. But it would feel inauthentic to give everything a renfair gloss and not try to present difficulties as they actually were.

Stevo Darkly said...

No offense to anyone, but I feel compelled to weigh in on jollyreaper's "hypersail" idea:

I like it. I'm intrigued. Personally, I love Age of Sail tropes. They are cool. They are fun. And transposing them to a future space setting is even cooler and funner.

If you can pull it off.

Good writers can.

There's not a lot of love for David Weber here. I've only read one of his books, myself. It was OK, but I've never got around to reading another. But, you know, the dude has his fans. He's not exactly sitting around in the poorhouse crying becuase he can't get anyone to buy his books.

To be honest, taking favorite old tropes and motifs and trying to make them work in a new way can be a large part of the fun. See Firefly. Famously, bad old science fiction stories took familiar Western tropes and simply transposed them into space. Firefly did this overtly -- but unlike the bad old SF, it added rich complex characters instead of cardboard heroes, and elevated the hackneyed into something fresh and different.

Personally, some of my favorite SF books of all time are David Drake's "Reaches" trilogy: Igniting the Reaches, Through the Breach, and Fireships. I've only read a few of Drake's books, but these stand out for me.

Drake often models his stories upon actual events from history. In this case, his "Reaches" stories are built upon Elizabethan Age of Discovery adventures of Sir Francis Drake and his contemporaries. Struggling Venus Colony is England; the powerful threatening North American Federation is Spain. The stories themselves have a neo-Elizabethan feel. The spacers are often brutal, ignorant men who curse each other with, "Whoreson!" The starships leak. The main ship weapons are the "plasma cannon" which as described sound a lot like the Casaba-howitzers discussed here, but when the captain orders, "Run out the guns!" there is a lot of manual labor involved in extending and aiming the guns because the automation is limited.

Sound cheesy? But Drake pulls it off, because he cleverly and carefully constructs a technological and historical/cultural background to justify these otherwise anachronistic-seeming tropes. He also draws upon his own experiences in Vietnam to add realism and grittiness to his often-horrifying battle scenes.

And IMO, he makes it all work. True, I worry a little bit about the massive amounts of reaction mass that I suspect must be used by his ships' high-thrust "plasma drives." I don't fully understand his "sponge-space" method of FTL travel. And I don't care too much for his concept of that flaw in the structure of the universe called "the Mirror." (Almost too much for me to take, and I'm glad the Mirror becomes increasing less important in each book.) But the stories and the characters are such that these things don't bother me much.

Just remember, the story isn't (usually) about the enabling technology. Maybe you don't want to over-explain your space propulsion system in your story. Just figure out how it works, and show how it behaves, and not go into excessive detail about why it works. Figure out the rules for yourself, and be consistent with them, so that the more obsessive techno-geeks in your audience can't find any obvious inconsistencies to pick apart. And then put this in the service of a good story, and you're good to go.

More in a little bit...

Stevo Darkly said...

There's been discussion about just how much to explain your enabling technology, especially if it's magitech. I've been thinking about this.

Usually it's said that the less explanation, the better. After all, in stories set in the modern age, the enabling technology is usually not explained. It's simply used. As the famous example goes, the hero doesn't jump into his car and shout, "I'm now engaging the Kettering ignition process! Stand by as I shift into R for 'reverse' thereby enabling the transmission gears to etc. etc." He just jumps into his car and squeals into pursuit of the bad guy.

But I'm thinking of one of my favorite books, Earthman Come Home -- the first written of James Blish's classic "Cities in Flight" series. Written in 1959, it's still enjoyable today (even if the Soviets are depicted as winning the Cold War, the superintelligent computers have vacuum tubes, and the main characters carry sliderules).

Blish opens ECH with a prologue that explains the history of his setting. He also talks about an enabling technology, the spindizzy drive, and takes the unusual step of trotting out a (fictional) equation, supposedly derived by real-life physics giants Dirac and Blackett, that "explains" the basic principles of the drive.

I can't recall any other classic story that purports to reveal the equation that allows the hyperdrive towork.

But maybe Blish took extreme measures because of extreme circumstances. After all, the spindizzy is allegedly capable of simultaneously enclosing an entire city in a nearly impenetrable force-field, lifting that entire city into the air against gravity, generating a one-gee artificial gravity field for the convenience of the city's residents, and propelling that entire city through space faster than light.

That's really rather fantastical. So I guess Blish thought it was worth taking the extra trouble of making up the "Blackett-Dirac equation" to give his flying city saga at least the superficial appearance of a hard scientific edge.

Now, elsewhere in his story, Blish also mentions futuristic-sounding weapons such as "Bethe blasters" and "mesotron rifles." Blish doesn't really explain the physics behind these devices -- he simply describes them in action, what they do on the most simple level, as if by a naive witness who doesn't know or care how the things work. When the Bethe blaster ray touches something material, it causes a fusion explosion -- period. Similar, when the main character runs away, he is shot at by a soldier carrying a mesotron rifle. Our hero ducks around the corner of a building; the rifle bolt misses him and hits the building, causing a patch of stone to glow white-hot and then slowly fade. From this, all we know about a mesotron rifle is that it would be very bad to be shot by one. But for the purposes of the story, that's all we need to know, and all we care about.

So I would say that usually you explain as little as possible -- but sometimes you explain a little more, just to give a hint that a seemingly fantastic element of the story is maybe not so pure fantasy after all.

Just don't overdo it.

jollyreaper said...

My dislike for Weber is strictly on account of the writing. The setting, what the hey. It felt too contrived to fit age of sail tropes exactly but no problem, I'm reading for the space opera. It fell apart with Harrington being so smelling wonderful at everything and the villains being cackling cliches and far too much padding with the big dramatic rebellion in Haven occurring off-screen after we'd been through how many books?

Glad you like the sail stuff. If you're really intrigued, send me your email and I can give you the whole writeup, see whatnyou think. gmuir77 @ gmail dot com.

Stevo Darkly said...

Last thing for tonight...

I wanted to mention that the website SF Signal recently asked published SF writers, aspiring writers and fans, "How Important is Plausible Science In Science Fiction?"

The responses are shown here.

This is not a scientific sample, nor the last word. But I think it's worth looking at.

Excerpts:

I've got a reputation for writing 'hard' science fiction, with rigorously worked-out and plausible ideas--but I can tell you right now that I've never written an SF novel that didn't hinge crucially on at least one utterly preposterous and impossible idea... Here's my rule: am I having fun? Yes? Then I'll keep reading. -- Karl Schroeder

I'd argue that scientific plausibility is vastly overrated -- and speaking as someone whose novels have actually been used as core texts in both science and philosophy courses, I should really be a poster boy for the anal-retentive science-huggers in the crowd.

The fact is, though, that the state of scientific knowledge itself changes daily. Twenty years ago, the concept of "dark energy" was fantasy. Today we've got leading physicists admitting at least the possibility of time travel. To slavishly adhere to what we "know" to be true today is to claim that we've already pinned down the fundamentals, that there are no paradigms left to shift -- and that's one of the most profoundly antiscientific sentiments I can imagine. -- Peter Watts

I think it comes down to making sure the science is in service to the story, not the other way around. You want your audience to lose themselves in the fiction, as if it were real -- while knowing full well that it isn't. That's part of the unspoken contract between writer and reader, filmmaker and filmgoer. Making sure one's science is at least marginally plausible is critical to building a credible fictional world -- otherwise readers/viewers will get pulled out of the story whenever something strains the willing suspension of disbelief to the breaking point. (*cough* Red matter. *cough*) The "rules" of the universe need not be consistent with real-world physical laws, but they should be consistent within that world. The flip side is that if you get too bogged down in nitpicky technical details, you'll interrupt the narrative flow to the point where it ruins the fantasy experience for your audience. -- Jennifer Ouellette

Readers will forgive a lot if the story is well done, but if the science in the story serves as a deus ex machina, time after time producing just what is needed just when it is needed, then plausibility goes out the window along with decent story lines. We all know that real science is not a genie offering unlimited wishes with no trade-offs. If the science in science fiction serves as that kind of genie, it destroys plausibility. -- John Hemry, author of the hated Lost Fleet series :)

jollyreaper said...

Readers will forgive a lot if the story is well done, but if the science in the story serves as a deus ex machina, time after time producing just what is needed just when it is needed, then plausibility goes out the window along with decent story lines. We all know that real science is not a genie offering unlimited wishes with no trade-offs. If the science in science fiction serves as that kind of genie, it destroys plausibility. -- John Hemry, author of the hated Lost Fleet series :)

I'm not a physics boffin or mathlete so most of the screwups in physics I'll likely miss so when I'm pointing out problems, you know there are glaring oversights. But worse than his whole ".1c is the top speed!" and "we'll just swing around from our .1c attack vector for a second pass!" bits is the characterization. We're talking thinner than planck length. Bad, bad, bad writing, bad plotting. Great premise and deceptive like cheep booze; you get in too far before you realize there's going to be a price to pay.

I'll repeat that the human part of the story is a bigger than to get wrong than the physics.

KraKon said...

Remember, I go in order of last to first...

"My dislike for Weber is strictly on account of the writing. The setting, what the hey. It felt too contrived to fit age of sail tropes exactly but no problem, I'm reading for the space opera. It fell apart with Harrington being so smelling wonderful at everything and the villains being cackling cliches and far too much padding with the big dramatic rebellion in Haven occurring off-screen after we'd been through how many books?"

Don't spoil the story!
Actually, I'd take a David Weber book over any of those brain farts that are clogging up the sf stand any day. 90% of sf is crud. Weber hits my 10%.

"Just don't overdo it."

I think that's the point where hard sf earns physics book quality, but loses all sense of immersion into the story (yay I'm in my ROCKET ship, powered by a Variable Specific Impulse Magnetoplasma Rocket, look how the uranium fissions in the reactor! Wow the heat is trasferred to a coolant that is used to DRIVE TURBINES THAT MAKE ELECTRICTY! That electric power is being used to....I'll finish. This is boring, even to me writing it).

"Sound cheesy? "

Cheesiness is in the mind of the beholder. I, not having been exposed to the sf literature of the 50's or 70's, don't have that impression when reading Arthur C Clarke or Pournelle or such. Just a vague impression that all of this is outdated thinking and built, even if correctly, on the wrong assumptions.

"I like it. I'm intrigued. Personally, I love Age of Sail tropes. They are cool. They are fun. And transposing them to a future space setting is even cooler and funner."

It is sad to see all sf settings falling under 4 catagories:
Age of Sail imitation. Right on some things (long travel times, preparing well ahead for a mission), wrong on others (hundreds of men needed, SAILING, lines of battle).
WWII imitation. Right on some things (motorized travel) plain wrong on just too many others (2D thinking, battleships in SPAACE, space fighters, set fleet battles...)
A completely wrong intertpretation of something else (napoleonic wars) usually mixed with above. Poorest quality.
Completely original, and based on real physics. Too bad that the only sure way to get the physics right is to copy what's done today (lunar lander, 20 minutes into the future, we get a mars lander), and extrapolate within capabilities. People who try this mess up when they try too hard to stick to reality on one side and find the most contrived scenarios for some fun to happen anywhere. Stephen Baxter's books for example. NASA tech, but he needed aliens for fun.

KraKon said...

"If I'm trying to create an idealized society I might pick the Muslims of that period but if I'm trying to find some nasty aggressors who are willing to travel great distances to kill people for God, gold and glory, the Europeans are a good model."

If we exclude the political changes and Western technology seeping in, 'Muslims' pretty much lived the same way from the year 1300 to the year 1830 (got colonized or turned into Ottoman Empire territory). And please, 'Muslims', 'Europeans' is such a general term that it becomes offensive. Yeah, all the Eastern Hemisphere can be described with one word, but try mixing up between Koreans and Japanese next time you meet an Asian. Kudos if you leave it at 'they're all the same'.
Back on track, I'd say they had it easier, because hygiene and regular washing was prescribed by religion, and the hot desert sun removed most of the stenches and bogs that plague European cities at that time.

""Brilliant Pebbles" were designed to patrol in an unpowered orbit encased in a lifejacket. Minimum effective mass was calculated to be in the neighbourhood of 2.5 Kg but a practical Brilliant Pebble would probably be closer to 20kg to include the fuel, intercept motor, communications systems and batteries and so on."

Ah so Brilliant Pebbles ARE BBODs after all. But why the name Brilliant Pebbles when they are just miniature KKVs, with nothing brilliant and certainly not as dumb as a pebble.

"No points for low eV drives, actually. Yeah, you can always burn, and always get something, but with a low exhaust velocity the mass ratios become prohibitive rather quickly."

But such low eV drives can use such a variety of abundant propellants that it is hard to deny their capablity to access higher mass ratios. A comet has a very large amount of water, something a nuclear electric plasma drive can't exploit.

jollyreaper said...

It is sad to see all sf settings falling under 4 catagories:
Age of Sail imitation. Right on some things (long travel times, preparing well ahead for a mission), wrong on others (hundreds of men needed, SAILING, lines of battle).


Not the case with hypersails.

"Hyperspace is the answer, a higher dimensional space-time coexisting with but separate from our own. The human mind grasps at metaphors to describe such a thing but is entirely unequal to the task. We call starships the machines that ply realspace and hyperspace but they bear little relation to the wood and metal constructs that sail the terrestrial oceans save for being vehicles built for a purpose. We talk of currents and eddies, of stellar shoals and gravitational storms but this is a poor attempt to make more familiar the things that do not lend themselves to human understanding. Hyperspace is not amenable to analogy; it simply is."

The ships themselves are very large, not just destroyers and battleships in space. They'll use rotational gravity but are so large we won't even see the free-spinning hab section since it's within the superstructure.

Much of the volume is given over to the bits that make up the ship -- anything left is devoted to cargo and the smallest part is crew accommodation.

There are no hyper-turing AI's but the expert systems are capable of handling all the routine work of keeping the ship functional. You're looking at a very minimal flight crew. The only increase in staffing would be if the ship were rigged for passengers and then you'd have a very large hotel staff but they would be essential to keeping the passengers happy and the flight crew would still be doing their same jobs as usual.

What I'm trying to avoid are any of the usual transplanted tropes. Serious men sitting in chairs in dimly-lit rooms looking at radar sweeps is going to seem as anachrostic in possibly even 50 years as a man in monocole and waistcoat twirling valves and pumping steam. Fine for a historical piece but don't tell me he's on a starship.

As for combat, there's no pew-pew in hyperspace. Visibility is poor so active patrolling is required. Combat involves ships whirling in a dance of combat, trying to force the opponent to cross the wake trailing behind his own ship. The wakes in hyperspace are deadly and can force a ship into a crash translation back to realspace, potentially destroying it. Realspace combat will have pew-pew. That's the question of playing with ranges -- I want the guy already in realspace to have a defensive advantage over any attacker. Someone is knocked out of hyperspace, now the victor can either run off and count it as a win or try to make sure the target is destroyed. He goes from a position of absolute advantage to taking a risk because he has no way of telling how damaged the opponent is. He could be an expanding cone of hard gamma rays and energetic dust or he could be wounded but alive, charging his laser banks and waiting for his attacker to show.

While I would be surprised if nobody else has already thought up something similar to this, what I can say with some confidence is I've never seen anything quite like it and it's not described in your list of imagination failures.

I would also say that the Warhammer fluff makes the Warp out to be more interesting than the writers do. Warp travel should always bear an element of risk and playing russian roulette with a thousand-cylinder revolver but the writers make it far more mundane with people traveling for business, pleasure, and even shipping mundane crap around.

Given the dangers of the warp, it should be like the spice caravans -- bloody goddamn expensive stuff but people will pay top dollar. They're not going to be going to that kind of risk to bring disposable plastic Happy Meal toys from the Far East. Someone who goes over there for an adventure is celebrated like a Marco Polo, it's not going to be your pensioner couple off on holiday.

Raymond said...

Krakon:

"But such low eV drives can use such a variety of abundant propellants that it is hard to deny their capablity to access higher mass ratios. A comet has a very large amount of water, something a nuclear electric plasma drive can't exploit."

A) Those propellants require energy input to be "cracked", before they can be used.

B) A nuke-electric plasma drive can certainly access water as a propellant. You just need to ionize it, same as whatever other gas you'd use (best is usually argon or xenon, due to being inert and having a much lower ionization energy than hydrogen).

C) Just to compare mass ratios, a nuke-electric drive with a 50 km/s exhaust velocity will have 30 km/s delta-v with a mass ratio of 2. To get the same dV, a hydrogen-oxygen rocket of 4.5 km/s eV will require a mass ratio of a whopping 785(!).

Rick said...

I'll just say in general that a good story is vastly more important than Realistic [TM] tech or science. In fact, the main point of 'realism' in those things, in some subgenres of SF, is to be consistent with the mood of the story.

For example, magical swords don't quite go with the mood of hardboiled detective fiction or gritty combat fiction.

(Although genre-bending is pretty much becoming a trope in its own right these days.)

Milo said...

Jollyreaper:

"I would also say that the Warhammer fluff makes the Warp out to be more interesting than the writers do. Warp travel should always bear an element of risk and playing russian roulette with a thousand-cylinder revolver but the writers make it far more mundane with people traveling for business, pleasure, and even shipping mundane crap around.

Given the dangers of the warp, it should be like the spice caravans -- bloody goddamn expensive stuff but people will pay top dollar. They're not going to be going to that kind of risk to bring disposable plastic Happy Meal toys from the Far East. Someone who goes over there for an adventure is celebrated like a Marco Polo, it's not going to be your pensioner couple off on holiday."


Warhammer 40000 has an empire. The Imperium has its uprisings and internal feuds, but on average it still holds together. You simply can't maintain an empire, even a loosely-controlled feudal one, across distances that you need to be Marco Polo to travel.



Rick:

"For example, magical swords don't quite go with the mood of hardboiled detective fiction or gritty combat fiction."

I'm sure magic swords can be written in a gritty way. Not all magic is going to be of the "it's sharper so you feel less pain" type. In the right (or wrong) world, a magic sword can do far worse things to you than just hacking off some body parts.

Tony said...

Rick:

"I'll just say in general that a good story is vastly more important than Realistic [TM] tech or science. In fact, the main point of 'realism' in those things, in some subgenres of SF, is to be consistent with the mood of the story."

Hmmm...I think I made a departure a while back without clearly signalling it. I'm not so much interested in Realism [TM] with SF as much as I am with Credibility [TM]. As previously pointed out, Realism [TM], from our perspective, can't take you very far into the future. It often leads to "cheese" from the POV of our not so distant future, reading what we're concerend about today.

So what's important is Credibility [TM], meaning consistent and nothing too incredible (obviously). And that's where I have to jump ship with hypersailing -- it's just too much "and now something magic happens" to be credible.

Thucydides said...

"Brilliant Pebbles" were brilliant since they were programmed to hunt down targets on their own without centralized battle management systems. At most, brilliant pebble interceptors would communicate amongst themselves for cooperative target engagements (without massive pile ons leaving unserviced targets elsewhere).

They were "pebbles" since they were much smaller than previous iterations of the idea (Space Interceptors have been studies since the 1950's). Even early versions of SDI contemplated multiple 100+ kg interceptors carried around in space "garages". A minimalistic 20 kg KKV is a pebble compared to the 100kg "Smart Rock".

Looking at Jollyreapers space combat reminds me a bit of the motorcycle battle in "Tron". If the concern of a captain is the destruction of a ship forced out of hyperspace, then he should launch a brace of nuclear warheads into realspace at the exit point of the opposing ship (something like firing a "Hedgehog" of depth charges at a crash diving U-boat in WWII). If done fast enough, the damaged ship in realspace will not have the time to react to the sudden nuclear attack.

I agree that if the FTL is not central to the plot, then pressing the "GO' button a la the Alderson drive makes good sense. (The Mote in God's Eye and "He fell into a dark hole" do depend on the nature of the Alderson drive to resolve as stories, but they are exceptions in the Pournellian universe)

Vernor Vinge has a pretty implausible hyperdrive/hyperspace in "A Fire upon the Deep", but since a lot of the story revolves around the nature of space as described by Vinge, this is also good sense in story terms.

Tony said...

jollyreaper:

I wanted to address this one bit specifically:

"So, how long until the computer can figure out hyperspace navigation? It can't. The nature of hyperspace falls into that weird kind of temperamental territory that's like dealing with people, it just doesn't lend itself to deterministic modeling. Hyperspace is a dimension apart from our own operating under its own rules and the sorts of things we've come to expect from physics and modeling this reality just don't fly over there."

By your own description, you have the ship's computers collecting and marshalling data for the use of the pilot. Well, even today, our poor, benighted selves, if we can collect and organize data, can find ways to program a computer to analyze and act on it. If you as a writer try to put this one over on your readership, you'll have every person with a computer science education throwing your book against the wall. And nowdays that's a lot of people.

Tony said...

Thucydides:

"'Brilliant Pebbles' were brilliant since they were programmed to hunt down targets on their own without centralized battle management systems. At most, brilliant pebble interceptors would communicate amongst themselves for cooperative target engagements (without massive pile ons leaving unserviced targets elsewhere)."

Sorry, but that's incorrect. SDI KE interceptors would have always been under positive control of whatever battle management system that eventually emerged. They were "brilliant" because they could actually find and engage their targets once instructed to, unlike bullets, contrasted with bullets or artillery shells, which were "dumb" because they couldn't do anything to help themselves once they were fired. There was no swarming or cooperative engagement involved, whatsoever.

jollyreaper said...


By your own description, you have the ship's computers collecting and marshalling data for the use of the pilot. Well, even today, our poor, benighted selves, if we can collect and organize data, can find ways to program a computer to analyze and act on it. If you as a writer try to put this one over on your readership, you'll have every person with a computer science education throwing your book against the wall. And nowdays that's a lot of people.


Allow me to rephrase this: By your own description, you have the MRI and medical imaging machines collecting and marshalling data for the use of the radiologists. Well, even today, our poor, benighted selves, if we can collect and organize data, can find ways to program a computer to analyze and act on it. Therefore, we don't have radiologists.

That's actually a case of yes and no. Right now, we still need the human to interpret the data. The machines aren't good enough yet. You want someone to tell you what the shadow on the x-ray is, you need a human to do it. The high mucky-mucks will pronounce that this is the realm of human intelligence and no machine can equal it.

Of course, we are working on algorithms to read the imagery and once those hit the market, we haven't proven machines can think, we've just proven that radiology isn't so complicated that only a human can do it.

There are certain human jobs that I consider likely to resist automation far into the future. There are certain human jobs that I think will be automated in the very near future. The question is how complex the job is, whether you need emotions and intuition and humanity to do it. By author fiat, the AI's can't get any better than expert systems and lack the human artistic flair that makes hyperspace navigation possible. It's also the reason why machine-generated music won't feel the same as something played by a human, why machines won't be able to write decent poetry or engaging novels. In this setting, by author fiat, the machines will never exceed their programming. Just from our perspective, the programming has gotten very, very advanced and the computers are awfully fast.

To put it a little flippantly, drivers and pilots are on the way out in the future. It might take some time to culturally wrap our brains around it but there are no technical impediments. It can be done, is being done as we speak. But I think it will be a very, very long time before a really convincing sexbot gets built. Sure, there's realdolls and you've got the japanese otaku falling in love with life-sized pillows with anime girls on them (I so wish I was making that up).

Now some would argue that a sexbot doesn't really have to feel human emotion, would only have to simulate it. And some would argue that it's no different from having a one-night stand or visiting a prostitute. And it probably would be a step up from the life-sized pillow. But it wouldn't take the place of a wife for most people, couldn't even begin to start.

Thucydides said...

"The military in wartime is described as 99% boredom, 1% terror."

The ultimate problem with these stories is that many people are stuck in the video game model of combat, where your glorious hero carves through hundreds or thousands of mooks by the time the story is over.

In fact, even if everyone fights to the death, it stands to reason that an average soldier will be involved in exactly two fights - one which he wins and one which he loses.

The rest of the story will be about tactical maneuvering before meeting the enemy, or will be told from someone else's perspective. In reality, a war is going to have no single unit that is present in every major battle right up until the climactic showdown - every bit of the war is fought by someone else.


http://www.wired.com/dangerroom/2009/11/most-realistic-war-game-ever/

Thucydides said...

Tony

I may have misinterpreted some of the SDI stuff, but one of the key issues that Brilliant Pebbles was designed to get around was single point of failure design flaws.

Multiple interceptors stored in garages in space or in launchers on the ground were considered high risk/value targets. So was centralized battle management, including the command nodes and communications systems.

"This system could operate autonomously. Its sensors would pick-up the threat rocket as it cleared the clouds after lift-off – independent of DSP or SBIRS-High. And it would independently track the flight trajectory of the boosting rocket and its payload after burnout – and provide this information to other “shooters” in the layered defense, independent of SBIRS-Low. Thus, Brilliant Pebbles would not only provide a capability to intercept attacking ballistic missiles in all their phases of flight, they would support other layers by providing critical tracking information."

http://www.highfrontier.org/Highfrontier/index.html

Raymond said...

Rick:

"For example, magical swords don't quite go with the mood of hardboiled detective fiction or gritty combat fiction."

I give you The Steel Remains, by Richard Morgan. Well, the sword isn't exactly magical, but it's close (fantasy world, some magic-like stuff, and the sword is a prized relic).

Anonymous said...

Anyway, after looking at the title of this post again, I think that I'll make a comment about laserstars; since it appears that all combat spacecraft (manned or unmanned) will have a mix of weapons; Laserstars (if built) will be classified as an armed spacecraft whose primary weapons system is a laser that takes up no less than 50% of the ship's mass and/or volume. Or, some other arbitrary number.

Ferrell

Rick said...

So far as I can tell, Brilliant Pebbles was essentially a marketing term.


In needing human pilots for FTL, it isn't all that hard to come up with a decently plausible justification. But 'FTL needs human pilots' is such a longstanding SF trope, and (to me!) has such a blatant element of special pleading, that it grumps me anyway.

Generally I think Tony has hit on an important point, that what really matters is not 'accuracy,' but credibility. Of course it is in the eye of the beholder, but when it comes to fiction everything is in the eye of the beholder. As I entitled a previous post, de gustibus non est disputandum, but that is no excuse for being lame!

Probably the most useful meta advice is to lie boldly.


Raymond -

As I had to acknowledge, genre bending has become a common technique. After all, my previous comment is pretty much just daring writers to write hardboiled about magical swords.

jollyreaper said...


In needing human pilots for FTL, it isn't all that hard to come up with a decently plausible justification. But 'FTL needs human pilots' is such a longstanding SF trope, and (to me!) has such a blatant element of special pleading, that it grumps me anyway.


If you don't do that, you're stuck writing about transhuman AI's. Realistically speaking, I do think a lot of our wars are going to wind up with the majority of the advanced army remotely controlling droids on the other side of the world and the locals doing their fighting and dying against them. There's some stories to tell there but if those aren't the stories you want to tell, you're SOL.

The Forever Peace looked at the consequence of soldiers fighting this kind of drone warfare. Personally, I think the consequences of a droid army are completely plausible, frightening, and I still can't believe Lucas somehow managed to nerf that into what we saw in the prequels.

Frankly, I do not think it stretches credulity to imagine combat infantry going drone or autowar in the next 50 years. Whether we do or don't will be a political decision, not a technical one.

Generally I think Tony has hit on an important point, that what really matters is not 'accuracy,' but credibility. Of course it is in the eye of the beholder, but when it comes to fiction everything is in the eye of the beholder. As I entitled a previous post, de gustibus non est disputandum, but that is no excuse for being lame!

Credibility varies from person to person but yeah, it's a mixture of plausibility, credibility, and authenticity.

As I had to acknowledge, genre bending has become a common technique. After all, my previous comment is pretty much just daring writers to write hardboiled about magical swords.


There's also a matter of the author's world view. The classic fantasy tropes from Rings have morality tied with physical appearance. The more beautiful the elf, the more worthy she is. (Galadriel.) There might be a special elf exception here since they are magical so what the characters are seeing are completely influenced by her glamour.

jollyreaper said...

In fiction from all over the world there's the tendency to engage in magical thinking -- if your heart wants it, you will get it. If you really really really put your all into it, you will win. Good triumphs over evil. God is watching out for us. A modern, cynical perspective can clash when trying to tell a story with a modern bent set in an older genre.

When I first encountered the idea of gods gaining their power from the support of their believers, I immediately thought of pyramid schemes. Later I saw that the Church of the Subgenius had worked it out in hysterical detail. It really set my mind to thinking about what a sword and sandals with physical gods story would be like if it weren't the priests but the gods themselves as the religious conmen.

The basic premise is you had the men of the first civilization inventing their own gods and religion as you would expect. Magic existing in this world, they are able to create a literal tower of babel, searching for the seat of the gods. They get there and nobody's home. But given that they have magic, they could pretty much create the system they assumed was there. Worship and prayer contributes mana from the faithful, it is concentrated within the godhead that is assumed by the wizards, you now have a pantheon of gods. They are now immortal and certainly have powers beyond mortal men but are still what you would call weakly god-like, their powers not absolute. They can't reverse time, bring souls back from the dead, pull the stars from the heavens, etc. But given that mortals die out, it becomes very easy for them to keep up the appearances of Greek gods. And when you get new gods, children of the elder gods, they aren't filled in on the old family history. As far as they are concerned, they're divine and have always been so.

Now just imagine the kind of politicking that would go on in a setting like that! Gods vs. gods, it would get nasty. The Venitian-style wars we talked about with the space elves would be turned up to 11 here.

Milo said...

Jollyreaper:

"Now some would argue that a sexbot doesn't really have to feel human emotion, would only have to simulate it."

Emotion? I think a sexbot's necessary emotional repertoire would be pretty limited. At least if it doesn't need to do anything except sex. (If you can build a robot that's capable of being an entertaining conversation partner, than adding a sex feature to your product would be comparatively trivial.)


"And some would argue that it's no different from having a one-night stand or visiting a prostitute."

The obvious corollary is that even if you could build a sexbot, there would be little point unless it's cheaper than just hiring a prostitute. (I think we will see widespread social acceptance of prostitution before we see widespread social acceptance of having sex with robots.)



Thucydides:

"http://www.wired.com/dangerroom/2009/11/most-realistic-war-game-ever/"

Isn't working for me. Care to summarize?

Milo said...

Rick:

"But 'FTL needs human pilots' is such a longstanding SF trope, and (to me!) has such a blatant element of special pleading, that it grumps me anyway."

The question is, do computers do everything in the world except for FTL? If so, then the special pleading is blindingly obvious. If not, then it's not so jarring anymore.

The trick is to justify the necessity of humans in a way that actually makes sense. "Mathematical calculations so complicated that no computer can do them" is bunk, because now you're trying to rope in a human to do the one thing computers do best. "There simply needs to be a human onboard for the drive to work, even though that human need not do anything particularly complicated except being there" is also the sort of thing that gets the readers' neighbors complaining about the noise on their walls.

Also consider allowing computer-controlled FTL that still works but is of lower quality (more likely to make judgement errors and get shipwrecked) than human FTL.


"After all, my previous comment is pretty much just daring writers to write hardboiled about magical swords."

Well, many stories use magic as a convenience - if you want your heroes to do something that isn't possible in the real world, or if you want them to not have to struggle with a problem that they would realistically have, then you can give them a magical solution to deal with it. But you don't have to use magic that way. Focus on the effects of fighting an enemy with powers you don't quite understand and don't know how to defend against, never even knowing what to expect next. (It doesn't have to be Cthulhu - even a weak enemy can be scary, if what little power it has challenges your norms. People are scared of bees.) Try treating magical curses with the same fear and loathing as poison gas in WWI trenches.


"Of course it is in the eye of the beholder, but when it comes to fiction everything is in the eye of the beholder."

You lose when people stop being interested in beholding your work.



Jollyreaper:

"Personally, I think the consequences of a droid army are completely plausible, frightening, and [...]"

Droids are definitely frightening if one side has them and the other doesn't. But that applies to any attempt to fight a technologically superior opponent.

If both sides have droids, then your soldiers will mostly be able to take cover behind your droids and so won't have so much to be frightened about.


"When I first encountered the idea of gods gaining their power from the support of their believers, I immediately thought of pyramid schemes."

"Become a god today! Simply declare your undying adulation and worship to the ten people listed below, then remove the bottom entry, add your own name on top, and send this message to all of your friends. If you don't do this, you might turn into a frog or something."


"They are now immortal and certainly have powers beyond mortal men but are still what you would call weakly god-like, their powers not absolute."

That applies to "gods" in all polytheistic religions.

Rick said...

If you don't do that, you're stuck writing about transhuman AI's.

I am not at all persuaded that foreseeable tech will lead to any such a thing. (Are chess programs that beat grandmasters 'transhuman?')

Lots of military robotics, yes; we'll probably see that. Used asymmetrically, they are just the 21st century version of

Whatever happens, we have got
The Maxim gun, and they have not.


Used symmetrically? I don't know, but the real problem for warfare between industrialized countries remains the same as it has been since 1945, or at least 1951.

Rick said...

"http://www.wired.com/dangerroom/2009/11/most-realistic-war-game-ever/"

Isn't working for me. Care to summarize?


It worked for me, but the summary is an Onion video clip headline:

Ultra-Realistic Modern Warfare Game Features Awaiting Orders, Repairing Trucks

Thucydides said...

The Wired piece was a rather hysterical satire of "First Person" video games, except instead of being a "First Person Shooter", the character was filling out forms, pulling guard duty and shooting the s**t with his buddies, repairing trucks in a depot...you know, the *REAL* military.

I can imagine the crew of a space platform (Laserstar, Kineticstar, C&C platform etc.) living a similar life during the long ballistic trajectories. Even a VASMIR powered ship capable of reaching Mars in 39 days will have the crew sitting around for about 30 days monitoring systems and doing busy work under the supervision of the Coxswain.

So the exciting fiction would take place during the final 41/2 days of the flight (unless you staged a drive failure or similar disaster during the first 41/2 days as you spiral out from Earth...)

Tony said...

Re: Thucydides WRT Brilliant Pebbles (BP)

The operative word in your quote is "could". A BP systems, supported by adequate supplemental sensors in a special purpose satellite constellation, could be allowed to fight by itself, under certain circumstances. But...

1. It's not at all certain that possitive control would be relinquished, except under all out attack. And the Soviets might very well have made a plan revolving around this reality, betting that the US would take so long verifying the nature and scope of the attack that by the time weapons release occurred, it would be too late.

2. Design freeze would have been in the 1995 time frame. Judging by what I know of computer hardware and software of that era, I have serious concerns that a lot of people were engaging in very irresponsible wishful thinking. I'm not at all certain that with today's technology a purely automated system could coordinate a response, unless it was deployed in overwhelming strength and a lot of inefficiencies were accepted.

Anonymous said...

Thucydides said:"So the exciting fiction would take place during the final 41/2 days of the flight (unless you staged a drive failure or similar disaster during the first 41/2 days as you spiral out from Earth...)"

Unless the crew has all been murdered and the colony has to go up (or do it from the ground) and discover why the emergency auto-park function of the ship's computer was engaged and finds cryptic messeges written in blood on the walls...

Ferrell

Scott said...

After all, my previous comment is pretty much just daring writers to write hardboiled about magical swords.
Already been done, in the Harry Dresden novels. Hardboiled detective who has been known to use one of the Swords of God (Amorrachius, Fidelis, and another one who's name escapes me). Yes, *those* swords, the ones with a nail from the Crucifixion used in their making.

Accuracy is important in storytelling, but it's accuracy to what you have established as possible. Accuracy to what we know now is neither required nor necessarily desired. Using an example from the Dresden novels, if the corresponding location in the realm of Faerie is a reflection of what the real-world location represents, then it makes perfect sense that jumping into Faerie from the FBI regional office (headquarters of the greatest hunters in the land of the US) would dump you into the receiving hall of the Wild Hunt (the headquarters of the greatest hunters in land of Faerie).

Now just imagine the kind of politicking that would go on in a setting like that! Gods vs. gods, it would get nasty. The Venitian-style wars we talked about with the space elves would be turned up to 11 here.

Oh, I like that idea...

And speaking as the guy who has spent way too much time bored waiting to arrive at the next port, you can always include drills of various things. Battlestations, fire, crewman gone stircrazy, etc.

Besides, there should always be a crewman underfoot working on something when the Captain goes down the passageway.

Thucydides said...

Tony

Perhaps even worse for you, this was conceptualized in the mid 1980's and the expectation by the optimists was to have the constellation in place in the early 1990s. I believe that this plan was trotted out one last time after the Persian Gulf War of 1991, with claims the constellation would have been able to seriously degrade the Scud attacks...

I am pretty sure that one of the reasons to think about a distributed system was a centralized battle management system really was beyond the state of the art in the 1980's. How well the individual KKVs could be programmed to track and attack individual targets with 80's state of the art is an open question.

jollyreaper said...


The question is, do computers do everything in the world except for FTL? If so, then the special pleading is blindingly obvious. If not, then it's not so jarring anymore.


Speaking in broad generalizations, the expert systems cleared out the need for middle-managers. The executive decisions are made by humans, work that lends itself to automation (which is a lot) is delegated to the expert systems. Anything requiring creativity or original thinking is pretty much impossible to automate. And yes, it would have profound implications for society. And this is stated with the caveat that it's how it'll work in this setting, not that I'm making a prediction of how it'll work out in real life.

The trick is to justify the necessity of humans in a way that actually makes sense. "Mathematical calculations so complicated that no computer can do them" is bunk, because now you're trying to rope in a human to do the one thing computers do best. "There simply needs to be a human onboard for the drive to work, even though that human need not do anything particularly complicated except being there" is also the sort of thing that gets the readers' neighbors complaining about the noise on their walls.


Nope. They're navigators and helmsmen like I said. The machines can't make sense of the data they gather from the sensors in hyperspace. Another comparison would be like our surgical robots. Right now, the surgeon is seeing data gathered by the sensors and issuing commands that are translated into motion by the actuators inside the unit. Eventually we will be able to remove the human from the loop but not right now. That's the same position the helmsmen and navigators are in with the added proviso that the machines will never ever be able to understand hyperspace well enough to navigate through it.

Consider translation software. Machine translation has come a long, long way but people are skeptical as to whether or not we'll ever see skilled human translators replaced. For routine business documents maybe but not for anything important. Translating literature from one language to another is an art. Now maybe I'll be surprised in ten years and they'll have this working perfectly at babelfish. Or maybe not.

jollyreaper said...


"Become a god today! Simply declare your undying adulation and worship to the ten people listed below, then remove the bottom entry, add your own name on top, and send this message to all of your friends. If you don't do this, you might turn into a frog or something."


More or less.

"They are now immortal and certainly have powers beyond mortal men but are still what you would call weakly god-like, their powers not absolute."

That applies to "gods" in all polytheistic religions.


Depends on who's telling the stories. I don't think it's even possible to kill a Greek god. The Norse gods always struck me as more interesting given their potential mortality.

At least as far as I'd imagined these gods, they would be less powerful than the Greek gods. The power level of the Christian conception of God has undergone serious buffing over the years. In the OT Yahweh is just one of the competing gods in a small corner of the planet laying claim to having created everything. The more we learn, the more expensive God's powers have to be to allow him to keep his position. If we did see Greek polytheism last until the modern age, I think the Olympians would have also seen some serious buffing.

jollyreaper said...


If you don't do that, you're stuck writing about transhuman AI's.

I am not at all persuaded that foreseeable tech will lead to any such a thing. (Are chess programs that beat grandmasters 'transhuman?')


Nope. And if we were making serious moves on getting out into space in the present day, I think we could leave transhuman AI's out of the picture. But it looks like we're taking the slow haul approach, hundreds of years until we're seriously out there. And so I have to wonder where computer tech will be by that point. I'm aware of the folly of projecting based on exponentials but I think that the computer tech we'll be dealing with in 200 years will be far past our ability to conceptualize. And thus it becomes very difficult to think of plausible designs for starships. We're going to be missing some really important stuff.

jollyreaper said...

Already been done, in the Harry Dresden novels. Hardboiled detective who has been known to use one of the Swords of God (Amorrachius, Fidelis, and another one who's name escapes me). Yes, *those* swords, the ones with a nail from the Crucifixion used in their making.


Pretty much all of the urban fantasy out there ends up failing hard on the credibility level, sadly. Dresden's a great example of this.

Personally, I love the concept and Butcher's a decent writer but he writes Dresden thick, very thick. And that's characteristic of so many urban fantasy heroes. I guess because they're cribbing so hard from hardboiled detective stories? The heroes are always in over their heads, in serious danger, and reacting instead of acting. You don't really get to see a brilliant plan come together that makes a satisfying amount of sense. The hero's survival is always due to author intervention.

Classic example from the Rachel Morgan series, Rachel's a witch working for a supernatural law enforcement group. They handle the stuff human law enforcement can't. Seeing as her job is as a state-employed bounty hunter (and later goes solo), she should be really conversant with the critters out there. Certainly she should know all the ins and outs concerning vampires.

Now the author puts her in with a new vampire roommate and then wants to create an opportunity for a conversation introducing a third character. So the vamp roommate is ready to go fangs out and ol' Rachel doesn't know why. It's up for this third character, a pureblood human and amateur magic dabbler to explain just what she was doing wrong, accidentally pressing the vamp's buttons and triggering feeding mode.

And that right there is a perfect example of blowing it. That kind of ignorance would be perfectly understandable if vamps weren't public knowledge or she simply didn't grow up around them. But she did and she bounty hunts. This is about on par with a cop being unaware of what the local gang colors are and taking a stroll through the neighborhood in the wrong duds.

Rick said...

jollyreaper -

And so I have to wonder where computer tech will be by that point.

My guess, worth what you paid: Mature, and not showing dramatic progress from year to year or even decade to decade.

(For that matter, how much have, say, word processors actually improved since 1991?)


Pretty much all of the urban fantasy out there ends up failing hard on the credibility level, sadly.

Perhaps genres don't mix after all, or not successfully. The classic hardboiled detectives, like Sam Spade, might not be PhDs, but they knew their way around town.

Milo said...

Jollyreaper:

"That's the same position the helmsmen and navigators are in with the added proviso that the machines will never ever be able to understand hyperspace well enough to navigate through it."

That's the kind of claim I don't like. Have you worked out your setting's future up to million of years?

The discovery of already hyperspace is something that currently known science says should never ever happen. I don't like the idea of people somehow being able to say with confidence that computer technology will never advance to the point where it's capable of automatic hyperspace navigation (something that, realistically, I think is bound to happen - though for the sake of plot you can easily decree that this time is several generations after the heroes' lifetime), nor that we will never be able to understand hyperspace as more than vaguely glimpsed chaos (again, this will eventually happen).


"Translating literature from one language to another is an art."

Literature itself is a form of art. Art, it should be noted, is something that only even exists as a human construction. The concept of art is meaningless without an intelligent mind to enjoy it.


"In the OT Yahweh is just one of the competing gods in a small corner of the planet laying claim to having created everything."

Although the Old Testament recognizes the existance of other gods besides YHWH, it also insists that YHWH is greater than all of them. (How much greater, it doesn't say. But it seems to insist he's undefeatable, at least.) So while neighboring pagans would have seen YHWH as simply "one among many competing gods", the Israelites themselves never did. (At least not since the present version of the Old Testament was completed.)


"If we did see Greek polytheism last until the modern age, I think the Olympians would have also seen some serious buffing."

"I am Zeus! Tremble in fear, puny mortals, for I- DID YOU JUST NUKE MOUNT OLYMPUS!?"

Although Odin should have an edge here. Gungnir is supposed to never miss its target, so that puts him ahead of our current anti-ballistic missiles. And it comes back after thrown, too.

And that one wolf (Fenrir in popular perception, though I think it was originally one of his offspring) is supposed to be fated to eat the sun, so I'm sure his digestive system should should be able to handle a puny atomic explosion, provided he can manage to chomp down on it.

Thucydides said...

When Fenrir breaks out of his chains, it is the start of Ragnarök, the downfall of the gods and the end of the universe.

Greek gods are also mortal by implication; they overthrew the Titans to assume control of the Universe, but no challengers to their positions exist in classical literature.

I am not as familiar with Hindu mythology, but as far as I understand the Universe is brought into being and ending by the actions of the gods, although I think they remain eternal.

Siva has the last word on Laserstars, I think:

If the radiance of a thousand suns
Were to burst at once into the sky
That would be like the splendour of the Mighty one…
I am become Death,
The destroyer of worlds.

Tony said...

jollyreaper:

"Nope. And if we were making serious moves on getting out into space in the present day, I think we could leave transhuman AI's out of the picture. But it looks like we're taking the slow haul approach, hundreds of years until we're seriously out there. And so I have to wonder where computer tech will be by that point. I'm aware of the folly of projecting based on exponentials but I think that the computer tech we'll be dealing with in 200 years will be far past our ability to conceptualize. And thus it becomes very difficult to think of plausible designs for starships. We're going to be missing some really important stuff."

The catch is that it has to be something that humans can conceptualize, at least eventually. Or else we won't be able to make it happen, because we couldn't draw up the designs, much less implement them. But humans seem to be able to conceptualize far in advance of what they can do. We're still using programming techniques invented 40 years ago. We've just got more hardware power to use them faster and in larger numbers than we used to. I wouldn't take that history and project anything more amazing than expert systems with some decent learning ability.

jollyreaper said...


Perhaps genres don't mix after all, or not successfully. The classic hardboiled detectives, like Sam Spade, might not be PhDs, but they knew their way around town.


Author shortcoming, I'd say. There's no reason why this sort of thing can't be handled well. But urban fantasy has exactly the same weakness as scifi -- you're making up EVERYTHING, or huge swatches of most of it. And because of this, it becomes very easy to write yourself into corners. Scifi and fantasy both play with the idea of true lie detectors and truth serums. That sort of thing would be world-changing and of course the implications are never fully explored. I mean seriously! A crime is committed, you round up the usual suspects and get a warrant to administer truth serum. Start asking questions until you find out who did it. Any sort of successful criminal enterprise is going to need to have wheels within wheels, Manchurian Candidate personality overlays and Total Recall hidden personalities so that someone can pass a test by genuinely believing they're telling the truth.

Another one that pops up from time to time in fantasy is ectoplasmic reconstruction of a crime scene. Usually it gets thrown in as a "well gee, I suppose we could try it" sort of thing that's done once and forgotten about. That's akin to someone suggesting fingerprints on a wine glass might help the police find the poisoner, they have success, and then nobody ever tries lifting prints ever again! *thunk* *thunk* *wall* *wall*

There's another factor as well which is the market. Publishers want writers who can crank out a franchise. It's extremely rare these days to see one-off novels, especially in urban fantasy. They want everything to be book 1 of cash cow. So whatever the writer's original inspiration, they're told to start stretching things out to the point of absurdity. The Rachel Morgan books got extended from 6 to 12 IIRC. That's gonna make for a whole lot of padding. The well's simply going to run dry. Not to mention that the publishers want a book a year if not more. Some writers end up working on two at a time.

I'm fascinated to see where things go with the kindle angle and self-publishing. We might be on the verge of a whole new revolution in fiction.

Anonymous said...

Everytime I catch up on this thread, I have to go back to the top and read the title to remind myself what the original topic was. :<

If and when we ever build laserstars, they'll most likely be used as part of a battle constellation or an orbital defense force; if they mount a mix of weapons, then they might take on solo missions, otherwise not.

Ferrell

jollyreaper said...


The discovery of already hyperspace is something that currently known science says should never ever happen. I don't like the idea of people somehow being able to say with confidence that computer technology will never advance to the point where it's capable of automatic hyperspace navigation (something that, realistically, I think is bound to happen - though for the sake of plot you can easily decree that this time is several generations after the heroes' lifetime), nor that we will never be able to understand hyperspace as more than vaguely glimpsed chaos (again, this will eventually happen).


In the real world, I would put the creation of sapient AI as a distinct possibility. Within the confines of this setting, I'm asserting it's something that cannot be done. It's one of those "run with this premise" ideas just like "ftl is possible" or "magic is real" or "the nazis won WWII."

So you need a sapient mind to navigate hyperspace, no one has yet successfully built a sapient AI, therefore machines can't navigate hyperspace. Now while most engineers would say that it's impossible to rule out the eventual creation of a sapient AI, hundreds of years of effort have all failed. But I'm sure there are some who will swear sapient AI's are forty years off, just like they've been for hundreds of years.

Now if we look to the Dune universe, it's easy to say "for sufficient amounts of time, 'not yet' is as good as 'never.'" Between the destruction of the thinking machines and the invention of the noship navigation computers, the Spacing Guild monopoly lasted for what, 20k years? "Meh. Still metastable." :)

jollyreaper said...


The catch is that it has to be something that humans can conceptualize, at least eventually. Or else we won't be able to make it happen, because we couldn't draw up the designs, much less implement them. But humans seem to be able to conceptualize far in advance of what they can do. We're still using programming techniques invented 40 years ago. We've just got more hardware power to use them faster and in larger numbers than we used to. I wouldn't take that history and project anything more amazing than expert systems with some decent learning ability.


Well, there's the whole failure of imagination problem. Now boffins will point out that nobody backing Columbus' voyage thought the world was flat, the educated people knew it was round. The question was whether or not he could reach India before the food ran out -- just how far away was it the long way? So when we have quotes like the president of IBM saying the worldwide market for computers would be about 6, I'm sure there were people with bigger thinking than that. But they probably weren't in much of a position to influence anything.

There's a continuing process of bringing new ideas to light so that the next step beyond that can be understood by the people holding the pursestrings.

As for the future of computers, I'm not out on a limb with Ray Kurzweil. I think the singularity is a neat idea but am not convinced it's inevitable. I could see it happening with transhuman AI's or I could see nothing but boring expert systems. I'm not calling it either way because I really don't know; I can certainly accept fiction that's working off either assumption.

Tony said...

jollyreaper:

"Well, there's the whole failure of imagination problem. Now boffins will point out that nobody backing Columbus' voyage thought the world was flat, the educated people knew it was round. The question was whether or not he could reach India before the food ran out -- just how far away was it the long way?"

Educated people knew the Earth was round and had figured out a close approximation of its circumference 1700 years before Columbus (Eratosthenes).

"So when we have quotes like the president of IBM saying the worldwide market for computers would be about 6, I'm sure there were people with bigger thinking than that. But they probably weren't in much of a position to influence anything."

The number was 5, and he didn't say that either. You ought to talk to my mother someday about how IBM got the DisplayWriter on so many corporate desktops in the early 1980s, in direct competition with their own electric typewriter business. Lack of vision is one accusation you can't lay on IBM. (Yes, they were a little slow picking up on the value of the multifunction PC, but they were considerably quicker tp catch up than Microsoft was with the Intertubes.)

"There's a continuing process of bringing new ideas to light so that the next step beyond that can be understood by the people holding the pursestrings."

Technologies mature. We haven't seen computing mature, but there's no reason to expect that it won't.

"As for the future of computers, I'm not out on a limb with Ray Kurzweil. I think the singularity is a neat idea but am not convinced it's inevitable."

It's an awful, misanthropic idea, at least as it's idealized by most people who have fallen in love with it.

"I could see it happening with transhuman AI's or I could see nothing but boring expert systems. I'm not calling it either way because I really don't know; I can certainly accept fiction that's working off either assumption."

I'm sure you could. All I'm saying is that what a lot of people see as earth-shaking advances in computing over the past 30 or so years is really all just proliferation into all available niches, enabled by miniaturization of brute-force methods and inevitable economies of scale. If you dig down deep into the guts of any modern software system, all you see is layer upon layer of arrays, trees, and hash tables, the desgins for which have been found in computer science textbooks since the Seventies.

Rick said...

A bit belatedly ... but if classical paganism had survived, I imagine it would have evolved into something a bit analogous to Hinduism, with the Olympian gods conceptualized within some more or less Neoplatonic intellectual framework.


Educated people knew the Earth was round and had figured out a close approximation of its circumference 1700 years before Columbus (Eratosthenes).

IIRC, Columbus used a gross underestimate of the Earth's size, perhaps with an exaggerated notion of the eastward extension of Asia, to put together his case that the Far East was within practical sailing distance west of Spain.

ElAntonius said...

I have to agree with Tony there: the base building blocks of the computer haven't changed all that much; what people associate with "revolutionary" is the creative applications people have found for the things (enabled by enhanced miniaturization and by enhanced transistor density).

That's not to say there's not a lot of advancement on the technical side, but for the most part it's not really visible to the layperson and we're talking about incremental process improvements and innovative ways of pushing data around, not revolutions in how hardware is made.

Tellingly, the last major architecture revolution at intel was the Pentium 4 (a massive failure), and the Core and i series of processors are all derived from the Pentium 3 architecture.

Milo said...

Re: urban fantasy, I like the concept, but there are several common urban fantasy tropes that really grate on me. Particularly they are (A) the idea that magic and "technology" are opposed and somehow interfere with each other, and (B) the idea that the supernatural world is hidden behind a masquerade and known only to few, while everyone else sees only a world indistinguishable from ours, and is oblivious to the clues even when they do encounter something supernatural.



Thucydides:

"Greek gods are also mortal by implication; they overthrew the Titans to assume control of the Universe, but no challengers to their positions exist in classical literature."

The Titans are sorta still around, though? Just imprisoned.

Of course, if you believe in an afterlife - as most religions do - then even being dead can be seen as "just imprisoned".

As for challenges, there are mortal humans who were able to injure gods in combat in Greek myth (there was even one guy who wounded two in one day), but I don't think anyone actually killed one.



Jollyreaper:

"Any sort of successful criminal enterprise is going to need to have wheels within wheels, Manchurian Candidate personality overlays and Total Recall hidden personalities so that someone can pass a test by genuinely believing they're telling the truth."

Or just an antidote to the truth serum.

But that might be noticed with drug testing...

But maybe you could build up an immunity or something.



Rick:

"A bit belatedly ... but if classical paganism had survived, I imagine it would have evolved into something a bit analogous to Hinduism, with the Olympian gods conceptualized within some more or less Neoplatonic intellectual framework."

You lost me.



ElAntonius:

"the base building blocks of the computer haven't changed all that much; what people associate with "revolutionary" is the creative applications people have found for the things"

So? The base building blocks of matter (atoms, particles) haven't changed either, but we sure find a lot of new ways to use them!

The best improvements I'm foreseeing in computer technology are more programs (including expert systems) that can do things that computers can't yet do, or can't do very well, today. Hardwarewise, computers are likely to keep getting faster, but that's just "more of the same".

jollyreaper said...


A bit belatedly ... but if classical paganism had survived, I imagine it would have evolved into something a bit analogous to Hinduism, with the Olympian gods conceptualized within some more or less Neoplatonic intellectual framework.


You still see that with various neo-pagan sects. Fans of the Cthulhu Mythos have done the same with Hastur being the personification of entropy.

jollyreaper said...


Re: urban fantasy, I like the concept, but there are several common urban fantasy tropes that really grate on me. Particularly they are (A) the idea that magic and "technology" are opposed and somehow interfere with each other,


Not always universal. There have been some pretty clever marriages of the two. I do like the idea of magic not lending itself to experimental verification or being reduced to a series of reproducible procedures. While the scientist can indeed observe a mage producing a fireball and the mage can teach an apprentice to do the same, the scientist can't figure out what's going on. He can see the mage brew a love potion but for the life of him he can't turn it into a mass production process the same way he was able to do with the abbey's beer.

and (B) the idea that the supernatural world is hidden behind a masquerade and known only to few, while everyone else sees only a world indistinguishable from ours, and is oblivious to the clues even when they do encounter something supernatural.


Yeah, it's the lazy way out.

The setting I have in mind, what happens if crap like the Exorcist is real? Spinning heads, spitting pea soup, and all the other crap that goes with it. There are unseen, demonic forces. The Church assures you it's proof of Satan's work on Earth. It's hard to remain completely skeptical when things can take you in your sleep if you dream the wrong things.

Society becomes overly repressive, manically religious, and incredibly conservative. Fascination with the occult is like mobster mania in the early 20th century and Hollywood has risen to the call. The general public knows the supernatural is out there, is terrified, but is grossly misinformed about virtually everything. The Church's position is that providing too much correct information to protect against demons might also point people in the wrong direction, towards summoning them. But the average citizen is no more likely to be the victim of demonic attack than a country farmer was likely to be leaned on by the mob in the 20's.

The Catholics would still be operating the Inquisition in full force. Nations with state churches like England will use holy offices to fight the occult while nations like the US will treat it as a matter of law enforcement, though the wall of separation between church and state has essentially been dismantled.

I think the kicker with all of this would be that black magic would be like steroids -- athletes juice because it works. The rich and powerful will use black magic because it works. And the consequences of black magic would make male lactation and genital shrinkage look like small potatoes.

Milo said...

Jollyreaper:

"Not always universal."

Oh, of course not. But common enough to annoy me.


"While the scientist can indeed observe a mage producing a fireball and the mage can teach an apprentice to do the same, the scientist can't figure out what's going on. He can see the mage brew a love potion but for the life of him he can't turn it into a mass production process the same way he was able to do with the abbey's beer."

Scientists cannot analyze art to the point of being able to mathematically calculate how to produce a good work of art, but they can still say some meaningful things about art.

If mages can brew love potions, then scientists can and will - in time - determine whether some people are more succeptible than others, what supposed defenses are genuinely effective against them, how long the effects last, what happens if you drink half a love potion and are then interrupted before finishing it, whether love potions can make you fall in love with someone not normally appropiate for your sexual orientation, and so on. The exact answers may vary from potion to potion, depending on the skill and the available resources of the mage making it, but these too can be quantized - or at least analyzed stochastically.


"Society becomes overly repressive, manically religious, and incredibly conservative."

Why would oppressing people and keeping them from rebelling or learning the truth be easier in a universe with supernatural forces than without? A little fear factor might help, but the demons would have to be very overwhelmingly terrifying for a 1984 type world to be at all plausible.

jollyreaper said...


If mages can brew love potions, then scientists can and will - in time - determine whether some people are more succeptible than others, what supposed defenses are genuinely effective against them, how long the effects last, what happens if you drink half a love potion and are then interrupted before finishing it, whether love potions can make you fall in love with someone not normally appropiate for your sexual orientation, and so on. The exact answers may vary from potion to potion, depending on the skill and the available resources of the mage making it, but these too can be quantized - or at least analyzed stochastically.


I think some of that might yield answers to scientific analysis but consider how difficult it would be if natural processes didn't operate according to principles that yield answers to scientific analysis? We know, for example, at what temperature water boils at. But wait, the temperature is lower high up on a mountain. Thus we discover air pressure is involved. It might take a bit of trial and error to figure all this out but once we know for sure, it can be put down in writing and experiments performed to everyone's satisfaction.

Now imagine you chuck all that out the window. What if a watched pot never boils? Period? No matter how much fire you give it? Ok, so may perhaps we can determine what level of observation is required. Both eyes? One eye? Full attention, taking a look every few minutes? And what if the only answer we have is that it's completely random? Same pot, same amount of fire beneath it, same volume of water, and when I stop minding it the thing boils in ten minutes and when you stop it boils in five? But tomorrow those figures reverse? And try as we might it's like the Flying Spaghetti Monster is reaching out with his noodly appendage.

Now THAT would be a system that would be ruinous to the scientific method, or at least trying to apply it to something magical.

Thucydides said...

Jollyreaper

Your Deamonic urban fantasy was partially written already:

Falling Angel by William Hjortsberg

(Filmed as "Angel Heart" starring Robert DeNiro and Mickey Rourke)

PI investigating the Prince of Darkness. The church is not formally involved, otherwise.

Enjoy

Milo said...

Jollyreaper:

"We know, for example, at what temperature water boils at. But wait, the temperature is lower high up on a mountain. Thus we discover air pressure is involved."

To be more specific, initially, experiments for boiling temperature will be producing slightly different results for no obvious reason. Scientists will still be able to give, however, a range of values with a lower and upper bound on the boiling point of water. They might be frustrated for some time at being unable to determine the the value with greater accuracy, but the information they already have is still quite useful. Knowing the boiling point of water to within an error of several degrees Celcius is still worthwhile.

Eventually someone will notice that the different experimental results appear to be correlated with geography, with scientists in different cities giving different values. This would suggest that the scatter in results is due to environmental factors rather than, say, differences in experimental procedure or equipment quality or the phase of the moon. They could then try tabulating various data on these locations in an attempt to determine while enviromental factor has the biggest effect. Someone will then notice that the dominant factor seems to be the altitude at which the experiment was performed.

At this point they still don't know which physical quality causes boiling temperatures to be different at different altitudes, but even without knowing this they can still use the data to interpolate an empirical formula for the relationship between boiling point and altitude. They could then use controlled experiments to test all sorts of different factors that might be related to altitude. Eventually one such experiment - testing boiling temperatures in artificially lowered air pressures at low altitudes or artificially heightened air pressures at high altitudes - will meet with success and explain the observed discrenpancies. (Of course, running these experiments requires access to technology capable of measuring and altering air pressure, which probably isn't a very simple task.)

Now the scientists can write a refined theory on the relationship of boiling temperature to air pressure, and note that the theory matches (with reasonable accuracy) the empirical formula from before.

With this mystery solved, scientists will then be able to predict the boiling temperature of water to within much greater accuracy, but there will still be some data scatter, because other as-yet unexplained factors (for example, how many impurities like salt are dissolved in the water) remain.

Science is a continuing process. There are always mysteries left to be answered, but even a very rudimentary answer (our initial boiling point estimate from above) - if it still follows the scientific process - is useful.

At its most basic, science is about determining which things work and which don't, and ceasing use of the ones which don't work. I would be hard-pressed to accept a depiction of magic where this attitude doesn't remain useful.

Milo said...

"What if a watched pot never boils? Period?"

That would in no way prevent me from conducting scientific experiments. I just put up a kettle, set my stopwatch, and leave to go work on a different experiment (preferably one designed to quickly distract me from conciously thinking about the kettle). Oh, and lock the door, so I don't have to worry about a bungling lab assistant coming in and watching the pot when he's not supposed to. When I (or my lab assistant) hear the whistle, I come back and stop my stopwatch, mark down the time it shows, and measure the temperature of the boiling water.


"Ok, so may perhaps we can determine what level of observation is required. Both eyes? One eye? Full attention, taking a look every few minutes?"

Watching it through a mirror? Having it observed by a nonsentient camera (and only watching the tape after the fact)? Attending the experiment while wearing a blindfold?


"And what if the only answer we have is that it's completely random?"

Then I can try to analyze the probability distribution. What's the average? Standard deviation? Is it a normal distribution, or maybe log-normal, or something more exotic? It's possible that there isn't a well-defined average. That's the case for the Cauchy distribution. But I can still give formulas for that, and while it doesn't have a mean, it does have a median.

jollyreaper said...

Could you develop a working steam engine under conditions like that? What about the bit where it behaves difference or other people and how tolerances could vary depending on the state if mind of the operator?

My hypothesis is that engineering would be cursed difficult if not impossible if the universal constants turned intonvariables that defied description and prediction.

What if there was no way by chemistry or alchemy to tell holy water from standard water except through exposure to something evil? Draw off a thimble of the water and add a pinch of vampire dust. Normal water does nothing an holy water boils as if red iron were quenched in it. Fine, you have a test but you can describe how hot iron and water react -- you can only guess with the vampire dust. It's not like sodium and water, no release of chemical energy.

Now try explaining why wool spun by a virgin girl at midnight in the light of a full moon makes for superior cloth with resistance to demonic creatures. You can't see any difference between really virgin wool and the slutty kind.

Now there have been some really clever books written where scientific folk from our world come to a place with magic and do some great science and engineering, turn thaumaturgy into an industrial art. There have also been some good books where technology and thaumaturgy just don't mix because they require completely different ways of thinking.

Personally, my fancy is tickled by the thought of a reasonable person trying to reason through the principles of magic and becoming more and more incensed at how unreasonable it is.

Thucydides said...

Hasn't S.M Sterling written a series of books about having the basic universal constants being subtly altered so that there is no more electricity and certain chemical reactions like gunpowder don't work anymore?

I think the main reason to write this was to have a backdrop to justify "sword and sorcery" writing with modern characters (drop the useless gun and learn archery. Suddenly all that time playing fantasy games and reading LOTR becomes on the job training!).

KraKon said...

I'll try and go down this time.

"A) Those propellants require energy input to be "cracked", before they can be used."

This can be done by using waste heat from the propulsion, as in using ice as coolant then flush it into the chamber. Waste heat from a nuclear thermal drive is going to be quite high, pretty much more than needed to liquify its remass on its own.

"B) A nuke-electric plasma drive can certainly access water as a propellant. You just need to ionize it, same as whatever other gas you'd use (best is usually argon or xenon, due to being inert and having a much lower ionization energy than hydrogen)."

But nuclear-electric plasma drives usually don't provide you with enough waste heat to IONIZE their own propellant. Except if they're unefficient, but even then they won't generate ionization-levels of heat. Or they're just goddam powerful that they can spare a very little fraction of their useful energy into ionizing remass, but in that case using an asteroid isn't sensible - put a proper hull around such a generator and get a zippy ship.

"C) Just to compare mass ratios, a nuke-electric drive with a 50 km/s exhaust velocity will have 30 km/s delta-v with a mass ratio of 2. To get the same dV, a hydrogen-oxygen rocket of 4.5 km/s eV will require a mass ratio of a whopping 785(!)."

While a nuclear thermal rocket, with 9km/s exhaust velocity, may weigh nearly three tons. Inside a hundred meter comet, it has 70685 tons of remass available. That's a dV of 90km/s, very cheap as well.

"Warhammer 40000 has an empire. The Imperium has its uprisings and internal feuds, but on average it still holds together. You simply can't maintain an empire, even a loosely-controlled feudal one, across distances that you need to be Marco Polo to travel."

Oh come one! Warp specifications are fluff afterthoughts in WH40K, and politics even worse. And its not the distance which made Marco Polo's journey special, it was the time taken.

"I'm not so much interested in Realism [TM] with SF as much as I am with Credibility [TM]. "

Top that. Credibility[TM] also comes with Consistency[TM], something I hope to achieve first.

"And that's where I have to jump ship with hypersailing -- it's just too much "and now something magic happens" to be credible."

Most readers (okay! I'LL) accept that the setting is consistent when the author specifically states: HERE BE MAGIC and THIS IS CREDIBLE. A consistent universe (with consequences and hardships of FTl travel well thought out) may not be credible (I tell ya, we ain't leaving this blue marble FOR THE NEXT 500 YEARS!!) but still a good read. And really, do enjoy a good novel less then a rock hard technical manual?

""Brilliant Pebbles" were brilliant since they were programmed to hunt down targets on their own without centralized battle management systems. "

Ah! Brilliant is a word that is glued to 'shiny' in my brain....AFAIK, smaller computers get exponentially less performant than their larger, more centralized bretheren. Recent tech breakthroughs has just made the point where they become TOO inefficient lower and lower.

"Looking at Jollyreapers space combat reminds me a bit of the motorcycle battle in "Tron""

No, you got it all wrong! It's like the aerial battle at the end of the film, but without the ground to allow the protagonists to save themselves with well timed dives (or the looping for that matter)!

KraKon said...

"By your own description, you have the ship's computers collecting and marshalling data for the use of the pilot. Well, even today, our poor, benighted selves, if we can collect and organize data, can find ways to program a computer to analyze and act on it. If you as a writer try to put this one over on your readership, you'll have every person with a computer science education throwing your book against the wall. And nowdays that's a lot of people."

I'll use the chinese room argument-the computer analyzing the hyperspace data is just reacting to input according to statistical rules (I think the OP ruled out sensors being used in hyperspace for picking up electromagnetic radiation, so no experimentation upon hyperspace medium). The computer is therefore an expert system-it reacts, but never understands what it is doing.

Milo-
"The question is, do computers do everything in the world except for FTL? If so, then the special pleading is blindingly obvious. If not, then it's not so jarring anymore."

The best solution then would be to sit down, write HUMIES MUST BE ON WARSHIPS and brainstorm all the myriad reasons why they would be needed there. Remove all the fanatasy stuff. Remove stuff that we're likely not to need humans for by the time of your setting. What are we left with? Maintenance, FTL handwave operators, tactitians, in-the-loop decision makers...

"Also consider allowing computer-controlled FTL that still works but is of lower quality (more likely to make judgement errors and get shipwrecked) than human FTL."

Or take the autopilot example. Today, flight hardware can easily handle the boring straight-line-just-maintain altitude stuff, which is the majority of the journey. Landing, takeoff, turbulent weather, combat maneouvering is where the man at the helm takes over. Transposing this to the hypersail setting, we could have entering and exiting hyperspace a human's job, while travelling inside it in a straight line something a computer could handle.

"You lose when people stop being interested in beholding your work."

You lose when the MAJORITY of potential readers lose interest. You don't lose because some emo kid brainwashed by Twilight doesn't get month long transits to Mars.

Thucydides-
"I can imagine the crew of a space platform (Laserstar, Kineticstar, C&C platform etc.) living a similar life during the long ballistic trajectories. Even a VASMIR powered ship capable of reaching Mars in 39 days will have the crew sitting around for about 30 days monitoring systems and doing busy work under the supervision of the Coxswain. "

Hurrah for the Holodeck.

Ferrel-
"Unless the crew has all been murdered and the colony has to go up (or do it from the ground) and discover why the emergency auto-park function of the ship's computer was engaged and finds cryptic messeges written in blood on the walls..."

But that wouldn't need to involve laserstar or interplanetary combat at all....and WE!WANT!EXPLOSIONS!

Milo-
"That's the kind of claim I don't like. Have you worked out your setting's future up to million of years?"

Good thing we don't set our settings in 1002011 AD.

KraKon said...

Tony-"The catch is that it has to be something that humans can conceptualize, at least eventually."

EVERYTHING invented or conceptualized until now has been in our heads for millenia. Flying for example, has passed from magical to routine. Counting the number of stars has led to Hubble, squinting eyes to IR night vision, throwing rocks to deorbiting asteroids...we are proficient at applying hard technical knowledge to crazy talk and wild dreams, until we get it right. The remaining stuff were surprises (really, we would never have discovered radioactivity by just thinking about it), but we still managed to find uses for it.

"We're still using programming techniques invented 40 years ago. "

And they're using maths made up thousands of years ago. If something works right, we'll keep on using it. Especially if it the only way to do it (so far, we use the binary system because all electronics work on on/off positions of their components. Invent a quantum computer with intermediary states and maybe we'll leave the binary system and familiar computing techniques).

Ferrel-"If and when we ever build laserstars, they'll most likely be used as part of a battle constellation or an orbital defense force; if they mount a mix of weapons, then they might take on solo missions, otherwise not."

I see lasertstars as never being purpose-built.
They'll be modular warships equipped with a laser, and since the only useful laser is the biggest BAL you can fit on the warship, we get a laserstar. They'll also NEVER go out solo, so that they can hit enemies on the sides, play tag in hostile environments, sent out scouts before bringing in the artillery, and bypass frontal plate armor. I see them being used in multiples of three, even if it is (my uni) a ship with three big drones.

Tony-"It's an awful, misanthropic idea, at least as it's idealized by most people who have fallen in love with it. "

Basically, it is THE big unconceptualizable idea in SF. No wonder it is just easier to ignore it or push it ever later into the future.

Milo-"So? The base building blocks of matter (atoms, particles) haven't changed either, but we sure find a lot of new ways to use them!"

To quibble-femtomatter and its applications is based on the particles WITHIN subatomic particles. We've got the plans, just not the tech to make them realisable.

Milo-"Oh, and lock the door, so I don't have to worry about a bungling lab assistant coming in and watching the pot when he's not supposed to. When I (or my lab assistant) hear the whistle, I come back and stop my stopwatch, mark down the time it shows, and measure the temperature of the boiling water."

To preserve sanity where science has failed: BURN THE HERETICTS! Really, an ideal solution is to burn down what you don't understand because you do not have the TOOLS to understand, that of course tributary to the phenomenon VIOLATING ALL HUMAN KNOWLEDGE.

KraKon said...

On laserstars-
I don't undertstand something to do with targeting systems.
Rick tells me that targeting is based upon your spot size at a given range. If something is smaller than your spot size, you can detect it and fire at it. For example, if your spot is 1m wide at 1000000km away, you'll be able to find, track, and hit 1m-wide objects 1000000km away. Your detection range is therefore 1m at 10e9m.

BUT

Wiki article says that maximal targeting accuracy for adaptive optics is 50microarcseconds. 1m is therefore detected at around 3600km away. This accuracy is given in arcseconds, so is independant of beam spot size or wavelength.

WHAT is the targeting accuracy then? The ability to illuminate a target Xm wide at Y distance? Or the ability to keep said beam within a circle Xm wide at Y distance? IR sensors can detect stuff millions of kilometers away...but even xrasers cannot hit a a fraction of that distance!

Transposing to my setting-
At 50 microarcseconds accuracy, 30cm wide missiles can be fired upon from 1200km away. At 80km/s, this limits their time dwelling within the danger zone to 15 seconds.
However, if we use the main laser as a defensive laser, we can achieve a spot size of 30cm diameter 125000km away. Does that mean that the missiles will get fired upon from Stupendous distance?

(This makes worlds of difference in how much armor the missiles need)

ElAntonius said...

jollyreaper: I doubt steam engines would be practical if the properties of water boiling were such, no.

However, saying that altering the properties of the world would invalidate science and engineering? Doubtful.

Hell, it happens all the time now. There's plenty of boundary cases that require new theory in our models to account for. Relativity is a pretty good example...the Newtonian models are pretty good until we get to some edge cases where things start to break down, and Relativity explains them.

If water only boiled when unobserved, the world would be different, but that would just be one more property of water.

Ditto with vampire dust and blessed water.

That kind of stuff sounds silly to us in the world today, but if it was evident in the world around us we'd all accept it as reality.

If the change happened suddenly it would be mass chaos as all sorts of things that used to work didn't, but I would think that would create a rush of new science and new engineering as critical new discoveries are made and we struggle to understand the new rules we play by.

When you think about it, it's pretty much like FTL. Our current scientific theories would be proven wrong if someone came up with a way of doing it, but in no way would that violate the scientific *process*.

Tony said...

KraKon:

"EVERYTHING invented or conceptualized until now has been in our heads for millenia. Flying for example..."

That's not what I was talking about. I was addressing the fact that no matter how long people have been dreaming about a thing, humans have to conceptualize the means. For example, as soon as autogyros were perfected, they became the commuter vehicle of the future. After the perfection of the helicopter, the concept was shifted to them. But in both cases the dream could not be supported by a practical conception of affordability, reliability, safety, and adequate simplification of piloting skills. SF authors just blackboxed all of that and wrote commuter helicpters into their stories on spec.

The same goes for strong AI. Authors blackbox it and then write about it. That doesn't mean it will happen, just because somebody can write about it.

"And they're using maths made up thousands of years ago. If something works right, we'll keep on using it. Especially if it the only way to do it (so far, we use the binary system because all electronics work on on/off positions of their components. Invent a quantum computer with intermediary states and maybe we'll leave the binary system and familiar computing techniques)."

The mathematical foundations of modern computing are a little bit more complex than what the Pythagoreans worked with. But given the ability to do binary arithmetic with digital logic, the basic building blocks of data structures and algorithms were all figured out pretty quickly. Everything done since has been elaboration, AFAICT. I'd be willing to bet that if quantum computing becomes commercially practical, it will turn out that only a couple of decades (at most) will be needed to transition from establishing the fundamentals to elaborative advancement at the margins. And it's entirely possible that no really new power will be conferred upon us, just more compressed power to do what we've been doing.

Tony said...

ElAntonius

"When you think about it, it's pretty much like FTL. Our current scientific theories would be proven wrong if someone came up with a way of doing it, but in no way would that violate the scientific *process*."

FTL would have to work without invalidating anything else we've already demonstrated experimentally. Which is a why a lot of fictional FTL hangs on the idea of working only in relatively flat space -- we know what works here on Earth, and out to almost the heliopause.

Now, having said that, changes in the fundamental nature of the universe via author fiat might in fact destroy science. If things can't be counted on to work the way they did yesterday, then what's the point of scientific investigation? You have to deal with what's happening today, which may be different from yesterday, which may may not be the same as tomorrow. Certainly many would try to investigate the change scientifically, and try to hold onto science for things that haven't changed. BUt it would all be informed by the fact that things can be changed, without notice, to an unpredictable condition. That pretty much undermines the entire foundation of scientific thought.

Anonymous said...

KraKon said:"Ferrel-
"Unless the crew has all been murdered and the colony has to go up (or do it from the ground) and discover why the emergency auto-park function of the ship's computer was engaged and finds cryptic messeges written in blood on the walls..."

But that wouldn't need to involve laserstar or interplanetary combat at all....and WE!WANT!EXPLOSIONS!"

So have the Laserstar on a routine Anti-Asteroid patrol (plot device), have their gig board the disabled ship (they could just have empty tanks)and then discover the bloody messages and murdered crew; they have to figure out the mystery before the Laserstar must blow up the runaway ship to prevent it from slamming into Mars. Mystery and big booms; something for everyone! :>

"I see lasertstars as never being purpose-built.
They'll be modular warships equipped with a laser, and since the only useful laser is the biggest BAL you can fit on the warship, we get a laserstar. They'll also NEVER go out solo, so that they can hit enemies on the sides, play tag in hostile environments, sent out scouts before bringing in the artillery, and bypass frontal plate armor. I see them being used in multiples of three, even if it is (my uni) a ship with three big drones. "

So, if they can go on solo patrols, they're not Laserstars? That's an easy to remember criteria for deciding if a warship is a Laserstar or not.

Tony, Milo, KraKon, et al: So, how many Fire Mages need to be onboard before a ship should be classified as a Laserstar? ;0

Ferrell

Tony said...

Ferrell:

"So, if they can go on solo patrols, they're not Laserstars? That's an easy to remember criteria for deciding if a warship is a Laserstar or not."

A ship acceptable for solo (or even small squadron) patol duties would not be so lopsided in capabilities. On missions that could range from showing the flag, to peacetime policing, to fighting the first battle of the next war, a laserstar's lack of flexibility would be a non-starter.

"Tony, Milo, KraKon, et al: So, how many Fire Mages need to be onboard before a ship should be classified as a Laserstar? ;0"

I don't know -- how many succubi does it take to screw in a lightbulb?

ElAntonius said...

Tony:

"FTL would have to work without invalidating anything else we've already demonstrated experimentally. Which is a why a lot of fictional FTL hangs on the idea of working only in relatively flat space -- we know what works here on Earth, and out to almost the heliopause."

Yes, that's true. My point is a bit more meta: if FTL is, say, enacted by a bunch of virgins chanting in Welsh over a live chicken, then our understanding of physics changes from "The world works this way" to "AN EXCEPTION?! We must understand it" and much experimentation and new science would ensue.

New theory explains exceptions or border cases, much like relativity does for newton, or quantum mechanics does for relativity. That doesn't mean that a new discovery is likely to invalidate all of science...it's liable to result in new theory, that's all.

"Now, having said that, changes in the fundamental nature of the universe via author fiat might in fact destroy science. If things can't be counted on to work the way they did yesterday, then what's the point of scientific investigation? You have to deal with what's happening today, which may be different from yesterday, which may may not be the same as tomorrow. Certainly many would try to investigate the change scientifically, and try to hold onto science for things that haven't changed. BUt it would all be informed by the fact that things can be changed, without notice, to an unpredictable condition. That pretty much undermines the entire foundation of scientific thought."

The unspoken assumption of my post is that the universe still follows rules at some core level. A totally random universe would invalidate the scientific process, but writing fiction in absence of rules is "challenging".

The second anything is deterministic in the world, there is room for the scientific process to attempt to understand it.

As a side note: this whole discussion skirts with the issue that most people don't really understand the scientific process. Models and observations are not the same thing. Not accusing anyone here of this, but it's something that frustrates me no end about the mass presentation of science and scientists.

Tony said...

ElAntonius:

"The unspoken assumption of my post is that the universe still follows rules at some core level. A totally random universe would invalidate the scientific process, but writing fiction in absence of rules is "challenging"."

But what if the rule is that the universe is controlled by capricious gods who change the game whenever they feel like it? Or even a just God or gods who deliver Divine retribution when humans screw the pooch?

ElAntonius said...

"But what if the rule is that the universe is controlled by capricious gods who change the game whenever they feel like it? Or even a just God or gods who deliver Divine retribution when humans screw the pooch?"

Are the gods omnipotent (is that even possible with multiple gods?) At some point sufficiently powerful god(s) are indistinguishable from just plain random anyway.

If we make the god(s) real (not to invoke a religious war here, I mean "real" in the sense of observable and interactable) then they are subject to study. Sure, they may resent this and kill those who try (Tower of Babel?) but that's another trope.

Let's say it takes a prayer to Poseidon to get any fire to light. Sure, our current understanding of fire is totally invalid in that scenario, but there's still plenty of questions a scientist might ask:

1) How much prayer is required?
2) What materials will light with prayer?
3) Is it only Poseidon or will other gods respond?

By adding Poseidon to the equation you've really only added another element to the Oxygen + Fuel equation for fire: Oxygen + Fuel + Poseidon's_Damn_Well_Feeling_Like_It.

We're pretty good at getting to the first two, and since fire is pretty important I suspect understanding the third would be pretty critical to the human race. It may not be physics so much as other sciences, but science it still is.

Even if you argue that Poseidon randomly decides to just remove or require various things, you really just reduce it to "please Poseidon and you get fire": still an explainable phenomena from our perspective and subject to scientific thought.

And that's the crux of it: science is really just getting at explaining phenomena. Gods that are real in the tangible sense are just advanced beings, not objects of faith.

The fact that our housebroken dog is incapable of, say, fetching food from the fridge is no impediment from it understanding our psychology well enough to manipulate us into doing so. While it's rudimentary from our perspective: "If I roll over when he says so, Master is pleased. Pleased Master gives me treats and affection."...that's science. Observation, hypothesis, experiment.

Anonymous said...

Tony:""Tony, Milo, KraKon, et al: So, how many Fire Mages need to be onboard before a ship should be classified as a Laserstar? ;0"

I don't know -- how many succubi does it take to screw in a lightbulb?"

Two; but it has to be a really big lightbulb...

Ferrell

Milo said...

Jollyreaper:

"What if there was no way by chemistry or alchemy to tell holy water from standard water except through exposure to something evil?"

There were cultures where warriors tested the sharpness of their swords on condemned criminals. Figure something out!


"Now try explaining why wool spun by a virgin girl at midnight in the light of a full moon makes for superior cloth with resistance to demonic creatures."

Hmm. If the wool is being spun by an automated industrial robot, is it the virginity of the person who designed the robot, the person who constructed the robot, or the person who's operating the robot (in the simple sense of telling it when to go and when to stop) that matters? Or do all three fail, and only handcrafted wool works?

Does it matter what gender the virgin is? Can you use children so young that they'd be virgins by default? What about old maidens? Or does it have to be a beautiful nubile girl? Can you use a technical virgin who has participated in some sexual acts but never had "proper" sex? What about a true virgin who nonetheless has a really dirty mind?

Anyway, even if you can't roboticize the chore, you can still run sweatshop factories with dozens of virgins working in a hand-operated assembly line to mass produce wool. (Make sure to occasionally test their clothes to make sure they're still virgins.) Victorian era textile factories already made heavy use of child labor anyway, so this would be trivial for them to work into their operating procedure. The full moon would be a bigger problem, frankly, but you can have your factory manufacture normal wool the rest of the month. I doubt demonic protection is in enough demand that it needs to exceed 3% of the clothing market anyway. And full moons are at least predictable enough. (I'd be wary of letting my factory run on the night of a lunar eclipse, though. That's bound to bad luck. Although I'll still want to try testing it once suitable safety precautions are taken.)



Tony:

"Now, having said that, changes in the fundamental nature of the universe via author fiat might in fact destroy science."

If you are being deliberately messed with by a sentient being, then understanding the world around you becomes a matter of psychology. Which is notoriously fuzzy. But not completely impenetrable.

If the speed at which water boils depends on how much the pot fairies like you, and it doesn't boil when watched because the pot fairies are really shy, then getting water to boil faster becomes a matter of diplomacy. But we now have an explanation for the observed behavior and can quantize it. If this morning you got a postcard from one of your pot fairies reading "You forgot to take down yesterday's kettle before most of the water boiled away! I HATE YOU! -Clarice", then you could reasonably predict that today's pot will boil more slowly than usual, if at all. Or else that it'll boil too quickly and explode.

Maybe one day there's an undersea volcano eruption, and it's big enough that most of the water-boiling fairies get called in to work on that project, so water elsewhere in the world boils more slowly until they can return to their normal station. If you didn't have the seismic data on hand, then this anomaly would be very difficult to explain.

Milo said...

KraKon:

"To quibble-femtomatter and its applications is based on the particles WITHIN subatomic particles."

The what now? I was under the impression that all experiments we've conducted so far have supported the notion that subatomic particles are indivisible.

I've heard some hypotheses of quarks being make of preons, but the evidence doesn't seem to support it.

We can't draw up any kind of meaningful plans on using subsubatomic particles until we discover some and are able to measure or predict meaningful properties.

Now if you actually wanted to quibble, you could point out that particle physicists occasionally play with tiny amounts of weird stuff like strange matter or antimatter.

Tony said...

ElAntonius:

"Are the gods omnipotent (is that even possible with multiple gods?) At some point sufficiently powerful god(s) are indistinguishable from just plain random anyway."

Part of being a god is having godlike powers.

"If we make the god(s) real...

Let's say it takes a prayer to Poseidon to get any fire to light...

...

...It may not be physics so much as other sciences, but science it still is."


You're redefining the characteristics of "god" to be functionally equivalent to "phenomenon" and proceeding from there. Since gods and phenomena are not the same thing -- by definition: one is natural, the other supernatural -- your argument, while clever, is fundamentally specious.

"And that's the crux of it: science is really just getting at explaining phenomena."

Sorry, but that's incorrect, in being too simplistic. Science is a systematic means of finding out reliable information about the world. You can't apply science to gods, because gods are capable of changing their minds about the order of things, unlike fuel, oxygen, and heat, which, in sufficient quantities and proportions, will always give you fire.

"The fact that our housebroken dog is incapable of, say, fetching food from the fridge is no impediment from it understanding our psychology well enough to manipulate us into doing so. While it's rudimentary from our perspective: "If I roll over when he says so, Master is pleased. Pleased Master gives me treats and affection."...that's science. Observation, hypothesis, experiment."

Actually a very good illustration of why pure empiricism is not science, in and of itself. Master can be having a bad day, or decide to put you on a diet.

Observations have to not only be confirmed over time, they have to be accompanied by a rational theory (which does not require any other valid observations to be contradicted) why there are no extrinsic factors, or at least identifies the limits of the observation's validity. A scientific dog would not only observe that a set of behaviors gets snacks, he would know what the limitations on that dynamic were. Except that dogs don't -- they can detect and react to changes in behavior, but they don't (and can't) understand that human behaviors out of their control were always part of the equation.

Milo said...

Tony:

"But what if the rule is that the universe is controlled by capricious gods who change the game whenever they feel like it? Or even a just God or gods who deliver Divine retribution when humans screw the pooch?"

Those gods have personalities. I can reasonably assume that wool spun by a virgin is more likely to have desirable properties in an area ruled by Artemis than Aphrodite.

If the gods are non-omnipotent, then there are limits to their powers that I may be able to discover.

Milo said...

Tony:

"gods and phenomena are not the same thing -- by definition: one is natural, the other supernatural"

The distinction between natural and supernatural is completely subjective and arbitrary. (As is unnatural, a third category that many people seem to consider distinct from both of the first two, typically applying to humans and their work - even though it's natural evolution that produced us and we still operate on the natural laws of physics and chemistry.) It implies that there is a certain way that things are "supposed" to be, and that there is an external force which is intruding on this ideal. But mortals have no right to say if gods are "supposed" to exist or not. All we can do is determine that gods do exist, whether we like it or not - and that the universe appears to be designed to work in concert with their presence, meaning that I would consider them "natural". (In this hypothetical fantasy universe we're discussing, that is.)

ElAntonius said...

Posting from my phone so I'll be more brief than I'd like. Sorry, but incomplete understanding does not mean science is not being applied.

A dog does not understand all the factors that lead to getting a treat, but defining that science must always fully model the real world is patently false. Newtonian mechanics aren't always correct either, but that doesn't make them "not science".

ElAntonius said...

A further comment: if gods are walking around the earth and granting miracles, they are now observable phenomena and aren't really supernatural. A world where the laws of physics are different does not entail a loss of the ability to study it.

Science is not an organization, religion, group or belief system. It is a method of studying the world around us, nothing more or less.

jollyreaper said...

So here's the question -- is it possible to imagine observable phenomena that cannot be explained scientifically? Bearing in mind that in the real world we have examples of things not yet explainable by science and a whole host of natural phenomena that were unexplainable for great swaths of time but were finally explained.

If we are talking clarketech magic then yes, I think we could explain all in time, even if it took thousands of years of maturation on our part. But what if we simply cannot build instruments that can even measure how magic operates?

Of course, that sort of thing could maybe be intentional. If humans could work magic, if shown how, then the gods would be looking to smite anyone who might pull a Prometheus or independently discover the secrets.

When the whole idea of putting together a virgin wool weaving factory wad mentioned, I couldn't help but to think applying the scientific method to magic would end up looking a lot like Saruman's great smoking works at Isengard. I know Turtledove did an alternative history with WWI reimagined as total war between magic-using nations but it was supposed to have been profoundly awful.

jollyreaper said...

I think this post got caught in spam -- not showing up in the thread right now, only email notification.


"Looking at Jollyreapers space combat reminds me a bit of the motorcycle battle in "Tron""

No, you got it all wrong! It's like the aerial battle at the end of the film, but without the ground to allow the protagonists to save themselves with well timed dives (or the looping for that matter)!


Actually, I'd conceived of the idea back when we'd only known of Tron 1.0. I only saw 2.0 this weekend and was struck by how bad the movie was and how the lightship fights looked like a really crappy rendition of what I was thinking. :)

The actual genesis of the idea came in a couple of parts:
1. Growing up around the water, I'm well aware of how dangerous wakes can be to smaller boats. Big ships command respect or you will be swamped.
2. The wake turbulence of large jets is amazingly strong and can pose a significant threat to smaller aircraft.
3. Realistic space combat would likely take place at cinematically unaccomodating distances. Would it be possible to come up with a case where knife-fighting range was required instead?
4. Could a ship's wake in hyperspace be used as a weapon since there's nothing else to really shoot with in there?
5. Oooh! The space rhinos from Star Control 2. Their afterburner weapons were fun to use, lay a stream of fire across where the enemy's trying to go, like the lightcycles in Tron laying down their barrier, but in three dimensions.

It's not exactly like the Tron cycles since the wake dissipates with time and distance.

The real pisser, of course, is that it would become exceedingly difficult to depict something like this cinematically. You have no external views of the ships for starters, that's right out. You get that in realspace but not hyperspace. So now you're left with looking at the abstracted tactical plot that would be visible to the crew and the hallucinogenic dreamscape of the navigator and helmsman. It's one of those things that works on paper but would be very difficult to translate to the screen. I'm thinking of the silly martial arts combat system from Crusade where the weapons officer is in a VR environment punching and kicking at ships to attack. You're just waiting for the plaster and wire trilithons to descend from the ceiling and dwarves will start dancing around them.


In ancient times, hundreds of years before the
dawn of history.
There lived a strange race of people...the Druids.

KraKon said...

"The real pisser, of course, is that it would become exceedingly difficult to depict something like this cinematically. You have no external views of the ships for starters, that's right out. You get that in realspace but not hyperspace. So now you're left with looking at the abstracted tactical plot that would be visible to the crew and the hallucinogenic dreamscape of the navigator and helmsman. It's one of those things that works on paper but would be very difficult to translate to the screen."

Or it might be exceedingly easy to do so. What you've just described is trying to find a way to represent objects you can't directly see. Sonar does this, it translates sound into images. You're translating hyperspace telepetry into visuals. What you'll give the director is absolute freedom to design a 3D immersion display of bundles of information that represt ships, and expanding ship wakes that represent danger. This could be made to be fun and interesting.

"I'm thinking of the silly martial arts combat system from Crusade where the weapons officer is in a VR environment punching and kicking at ships to attack. You're just waiting for the plaster and wire trilithons to descend from the ceiling and dwarves will start dancing around them. "

That's just a plain stupid method that worked according to this logic:
Space fighters:cool
Martial arts: cool
Martial arts space combat in fighters? Cooler!

jollyreaper said...

In visualizing hypersoace combat with the tactical plot, re best I could come up with is a mix between the holodisplay from the death star briefing in ROTJ and the holographic traffic system in ghost in the shell. But I don't have a sense of how to make it something other than bewildering.

I've yet to see a really good representation of a good 3D plot for 3D info. Radars right now just do it in 2D because planes can only fly so high and ground position is the far greater matter. The human eye wants a flat display and any attempts at 3D on 2D screens becomes a mess. Homeworld was an ambitious game but half the challenge was figuring out what you were looking at! If it was projected in 3G in front of me, would it not be even more confusing with labels and vectors covering up more distant targets? Would I have gesture controls or a wand or 3D mouse for navigation?

It seems easier to do it in prose and not have to worry about actually showing it. But I'm not a graphics guy. Maybe there's stuff already out there that will blow my mind?

ElAntonius said...

jollyreaper: There's absolutely things that we can observe but can't figure out. And sufficiently powerful gods might well object quite violently to vivisection, making their study rather difficult.

We might never figure out how to imbue a computer with independent thought, or how to make a dog get a 1600 on the SATs, or how to grant eternal life to ourselves, but machine learning, animal intelligence, and medicine are all science despite the fact that questions may never get answered.

To say science doesn't exist is to say learning doesn't. I don't care how capricious or violent the gods are, the second you write a story about the loss of learning in the human race is the day you write a story about humans no longer being human.

Thucydides said...

Jollyreaper, I'll be your Huckleberry

Visuals of being swamped by a hyperspace wake were pioneered by the first Star Trek series. The director has the camera mount violently tilted back and forth while the crew rolls on the floor in sync. ;)

Based on your description of Hyperspace, there can be no tactical plots, you have described hyperspace as being impenetrable to most sensors and computer logic. The best I can think of (using your constraints) would be some sort of "waterfall" display similar to what a sonar operator would use today that could display the amplitude of "waves" in hyperspace. A ships wake would display different characteristics than a natural wave. Three operators are on duty at all times, manning the X, Y and Z axis display. If the sensor opaque environment invalidates all sorts of EM, then three Welsh virgins are needed to cover the three axis instead. A ship with 12 Welsh virgins aboard (6 hr shifts and a few spare operators) would give rise to many

...interesting...

stories and plots, few of which have to do with space travel ;)

Tony said...

Milo:

"Those gods have personalities."

Precisely. Phenomena dob't have personalities. I know where you're going -- personality implies tendency. But it also implies unpredictability, no matter how much data you have. Phenomena only imply unpredictability to the degree that your data are incomplete.

"The distinction between natural and supernatural is completely subjective and arbitrary. (As is unnatural, a third category that many people seem to consider distinct from both of the first two, typically applying to humans and their work - even though it's natural evolution that produced us and we still operate on the natural laws of physics and chemistry.) It implies that there is a certain way that things are "supposed" to be, and that there is an external force which is intruding on this ideal. But mortals have no right to say if gods are "supposed" to exist or not. All we can do is determine that gods do exist, whether we like it or not - and that the universe appears to be designed to work in concert with their presence, meaning that I would consider them "natural". (In this hypothetical fantasy universe we're discussing, that is.)"

"Natural" is not synonymous with "existant". Natural means fololowing the rules of nature. Supernatural means outside the rules of nature. Gods are, by definition, supernatural -- they can change the rules when and where they feel like it. Natural phenomena -- and even mortal man -- are constrained to follow the rules the gods make, and contend with the changes the gods impose.

Interesting note: when people talk of other persons being "gods" one of the things they most often mean is that such a person makes his own rules, and is not bound by the rules us mere mortals have to follow. It is not absolutely true, of course, but through some combination of charisma, beauty, intelligence, strength, and courage, these people do seem to be able to do what we wish we could most do -- escape the bounds of everyday life and be whoever or whatever we want to be.

jollyreaper said...


Based on your description of Hyperspace, there can be no tactical plots, you have described hyperspace as being impenetrable to most sensors and computer logic. The best I can think of (using your constraints) would be some sort of "waterfall" display similar to what a sonar operator would use today that could display the amplitude of "waves" in hyperspace.


I've seen those simulated in games and they're pretty cool. What I was thinking for the plot is that the data would be represented on a display. You have the waterfall display, yes, but you also have a screen where symbols are displayed representing various contacts. There's uncertainty as to what you're seeing so there's the effort placed to analyze the sounds and get a valid ID. Woe betide the sonar op who mistags a contact as hostile and the ship engages only to find out that it was civilian.

jollyreaper said...

One thing that made me go "hmm" when thinking about this was a HUD upgrade for the F-22 I saw in PopSci years back. It was basically augmented reality for the pilot. The landscape would be filled with transparent and colored spheres representing radar detection ranges, SAM engagement envelopes, threats from known troop concentrations for small arms fire, etc. It's taking tons of data that might not make any sense to a human being in the raw and translating it into something our visually-oriented minds can process. Same way we convert sound to something more visual so we can get a proper gander at it.

A ships wake would display different characteristics than a natural wave. Three operators are on duty at all times, manning the X, Y and Z axis display. If the sensor opaque environment invalidates all sorts of EM, then three Welsh virgins are needed to cover the three axis instead. A ship with 12 Welsh virgins aboard (6 hr shifts and a few spare operators) would give rise to many

...interesting...

stories and plots, few of which have to do with space travel ;)


My chief concern would be the young rakes in the junior officer corps devirginizing our welsh maidens. That'd destruction of Navy property, bucko!

Tony said...

ElAntonius:

"Sorry, but incomplete understanding does not mean science is not being applied.

A dog does not understand all the factors that lead to getting a treat, but defining that science must always fully model the real world is patently false. Newtonian mechanics aren't always correct either, but that doesn't make them 'not science'."


Newtonian mechanics are always correct, within certain recognized bounds. That's the difference between the empiricist dog and the human scientist. The dog's experience of another being's behaviors under stimuli are totally reliant on that other being not changing on a whim, or in response to extrinsic circumstance. Newton's quantification of the properties of bodies in motion is good everywhere, at any time. There are no extrinsic circumstances possible.

Science is not mere observation and categorization. Science is finding out reliable information. The difference between the empiricist dog and the human scientist is that the scientist can identify and quantify the constraints on his observations and analyses, thus making his conclusions reliable within those bounds. The dog can't -- he doesn't and can't know where Masterly intrinsics end and environmental extrinsics begin.

"A further comment: if gods are walking around the earth and granting miracles, they are now observable phenomena and aren't really supernatural. A world where the laws of physics are different does not entail a loss of the ability to study it."

1. Gods do not need to make themselves tangibly apparent to change the rules of nature.

2. Even if gods do appear in person from time to time, that does not mean they are bound by the rules of nature. The difference between natural and supernatural is not the difference between the seen and unseen, but the difference between being bound by the rules of nature and not being bound by them.

If Gods change the rules seemingly arbitrarily, how can science work? We all become dogs that can't make reliable predictions about the world. And without reliable predictability, knowledge ceases to be science and just becomes a set of wroking hypotheses subject to change at any time.

"Science is not an organization, religion, group or belief system. It is a method of studying the world around us, nothing more or less."

You continue to leave out the most important part: science only means something when its predictions are reliable. Methodically studying the world around you is nothing to write home about, unless you come to correct conclusions that reliably predict how the world will work under given conditions.

KraKon said...

"It's a slow mind morning, and I'm afraid your example for laser-thermal missile waves completely eludes me. I'm not sure how those numbers are being added up. (Why 35 missiles per wave, 630 total, etc.?) "

The full thing is on sfconsim-l, I took the numbers from there.
I reworked to account for defensive lasers using pulsing. Increased armor led to a 30kg dry mass missile, meaning a fully loaded mass of 300kg.
The drive laser provides 4GW of power to each LTM, half of which is converted into the missile's kinetic energy. The exhaust velocity is 40km/s, so we have a mean acceleration of 183g (33g at launch, 333g at target). To reach 80km/s, the missile takes 43s. The first missile can be launched at 5.8km/s, with its speed topped up later. Firing 10000km away, with a zone 1200km distant from the target (explanation later), we have 25 and a half minutes to play around with before the first missile enters the zone. During this time, each laser can accelerate 34 more missile to 80km/s. There are 6 ships in both attacking and defending constellations. Each manned ship is equipped with 20GW generators, feeding one onboard laser (4GW) and two other lasers mounted on drones (4GW again). This means we have access to 18 drive lasers, for a total of 630 missiles directed at a single ship of the opposing constellation.
The 1200km zone is where the enemy can obtain targeting solutions of the 30cm wide missiles. No-one has replied to the detection question, meaning I don't have a better figure for 50 microarcsecond detectors. In this zone, the drive lasers switch from accelerating the missiles to directing their dodging, jinking and defense penetration efforts. Velocity is added till tanks are dry (we do have 12km/s to use in 15s, so better burn it than waste it).

From there I established the wave-per-wave attrition warfare. This neglects all of the more exciting battles and twisted scenarios I can come up with, for a straight head-to-head finished over two hours and a half confrontation, no-one moving or getting lucky.

Rick said...

The discussion has moved on, but ...

Krakon -

Wiki article says that maximal targeting accuracy for adaptive optics is 50microarcseconds. 1m is therefore detected at around 3600km away. This accuracy is given in arcseconds, so is independant of beam spot size or wavelength.

Micro-or milliarcseconds? I'm looking at Wikipedia, and it says an 8-10 meter telescope can achieve an angular resolution of 30-60 millarcseconds.

50 milliarcseconds corresponds to 1 meter at 4125 km, or 30 cm at 1237 km. (If I'm doing this right!)


Transposing to my setting-
At 50 microarcseconds accuracy, 30cm wide missiles can be fired upon from 1200km away. At 80km/s, this limits their time dwelling within the danger zone to 15 seconds.
However, if we use the main laser as a defensive laser, we can achieve a spot size of 30cm diameter 125000km away. Does that mean that the missiles will get fired upon from Stupendous distance?

(This makes worlds of difference in how much armor the missiles need)


Again some milli/micro confusion? I'll go by Wiki's 30-60 milliarcsecond figure, rounded to 50 mas.

Laser spot size uses (IIRC) a slightly different formula from telescope resolution but let's just say that you can achieve a well-aimed laser spot size of 30 cm at about 1200 km.

You can illuminate the target at much longer range - the spot will simply be much larger than the target, so only a small fraction of beam energy actually hits the target.

Example: At 12,000 km your spot size will be 3 meters, and about 1 percent of beam energy actually hits the target. But if total beam energy is 100 MW, you're still putting a megawatt of energy onto the target, or about 1400 watts/cm2.

Note that this intensity yields a blackbody temperature of about 3500-4000 K - just hot enough to melt tungsten or sublimate graphite. Consult Luke's laser sims for how fast you'll burn through, and possible advantage from a pulse laser.

Rick said...

Krakon -

WE!WANT!EXPLOSIONS!

Or at least impressive zaps.


On science as a mode of thought, one obvious and familiar constraint is when dealing with entities of a human-like level of complexity. Such as ... humans.

After all, in spite of the term 'social science,' the social disciplines are not much like physics. Once whatever your doing starts to involve negotiating with gods or daemons, the whole process becomes in some sense political, and the predictability of outcomes falls off dramatically.

ElAntonius said...

Tony: The scientific method makes no judgements about the reliability of any data it produces; it is a method to increase, not guarantee, reliability.

Newtonian mechanics are NOT a description of the workings of the universe; they are a model, a best guess approximation of observable phenomena so we can make predictions. In fact, they're usually quite incorrect: it's just that the predictions they make are good enough for the level of precision required.

A (ridiculously) sufficiently detailed model of, say, me throwing darts at a board might be able to accurately predict exactly where each dart I throw will go, but such a task is herculean in effort and pretty much worthless.

And yes, in the face of sufficiently powerful and capricious beings, we are become as dogs. I still fail to see how that invalidates science...a god's blessing is now a natural law, no different than requiring oxygen for fire. And if a god can arbitrarily change natural laws, that's fine too: the only natural law becomes "a wizard does it", and while physics may be invalidated I'm almost certain that other fields such as parapsychology (GHOSTBUSTERS!) become important.

In either case, we're far afield of the original point; which dealt with beings and happenings of quite a bit less power. Active suppression of the human race by gods may well result in us not doing science any more, but that's because they've cowed us with power, not because the world can no longer be studied. The thing I was originally responding to was "like our world, but some people can waggle their fingers and make fire out of nothing".

Also, do you own pets? Most pet owners will tell you that pets are quite adept at reading our cues...their information about their owners is far more reliable than you might think.


Rick - Yes, that's my point. Our knowledge might get considerably softer and our ability to effect change in the world would be totally unreliable, but that does not inherently preclude curiosity and science.

Science is, succinctly:
1) I saw something happen.
2) I think this is why it happens.
3) I've devised an experiment that could disprove my 2).
4) The experiment has either disproved 2), was inconclusive, or reinforced 2).
5) Based on 4), react.

1) I saw a bowling ball dropped at the same time as a feather hit the ground first.
2) I think this is because bowling balls are heavier.
3) I will drop bowling balls and feather in controlled conditions, removing every variable I can.
4) I observed that in some cases the feather hit at the same time, namely when we removed air.
5) The bowling ball does not drop faster due to weight. New 2) required (air probably a good place to think about)

Milo said...

Personally, I find the mystery of something that has an explanation that we haven't figured out yet to be more compelling than simply saying that there isn't an explanation. Leave just enough tantalizing clues on how things work to keep people coming back for more.

Even when dealing with people, which are more unpredictable than rigid phenomena, if they at some point do an unexpected (seemingly out of character) action that has a serious effect on the plot, it's more satisfying if you eventually learn the background behind the deep-seated emotional turmoil (or whatever) that drove them to do that. People acting in ways that make no sense for their personality breaks suspension of disbelief even faster than altering the laws of physics.



KraKon:

"What you'll give the director is absolute freedom to design a 3D immersion display of bundles of information that represt ships, and expanding ship wakes that represent danger. This could be made to be fun and interesting."

The problem is that realistic military interfaces are designed not for coolness and flair, but rather for clarity and lack of distraction. Soldiers only put up with cool and flashy explosions all around them when they have no choice.



Jollyreaper:

"Would I have gesture controls or a wand or 3D mouse for navigation?"

Wiimote?



Thucydides:

"three Welsh virgins are needed to cover the three axis instead. A ship with 12 Welsh virgins aboard (6 hr shifts and a few spare operators) would give rise to many ...interesting... stories and plots, few of which have to do with space travel ;)"

Most importantly that once you have redundant virgins, it's no longer so critical that all them remain virgins until the end of the trip...



Tony:

"I know where you're going -- personality implies tendency. But it also implies unpredictability, no matter how much data you have."

Our personalities come down to logical physical processes in our brains. We cannot accurately predict them because they succumb to mathematical chaos, not because they do not obey science.


""Natural" is not synonymous with "existant". Natural means following the rules of nature."

What is "nature"? If gods existed before the mortal world was even created, then are they not more natural than us? We're the artificial creations.


"Natural phenomena -- and even mortal man -- are constrained to follow the rules the gods make, and contend with the changes the gods impose."

Gods must also contend with each other. Mythology is rife with gods working at cross purposes. What determines who wins such a contest? An even higher god?


"Methodically studying the world around you is nothing to write home about, unless you come to correct conclusions that reliably predict how the world will work under given conditions."

No. An unreliable calculation is still scientific, as long as you can calculate stochastically how unreliable it is.

Milo said...

You know, I'm getting really tired of the spam filter making it hard for me to tell if my post even made it through.

Tony said...

ElAntonius:

"The scientific method makes no judgements about the reliability of any data it produces; it is a method to increase, not guarantee, reliability."

First of all, there is no "scientific method". Newton himself did not follow the cookbook obervation -> hypothesis -> test formula when dealing with gravitation. He just applied mathematical analysis to observable fact and derived laws with sufficient predictive power to be usefull. He never ventured a theory.

Much of Early Modern science proceeded this way. Copernicus and Galileo both were much more interested in what observation of physical phenomena implied about physical effect that they were about physical causees. What we call scientific method is really just a theory about discovering causes, not a method of finding stuff out. discovering facts is easy enough. It only requires the proper instruments and a conviction to believe the evidence of your own eyes.

Science, in its most elemental form, is about reducing observed fact to quantifications called "laws", which can be used to make reliable predictions. Scientific hypothesis, or "theory", is an elaboration that directs further investigation into causes, which often leads to the discovery of further facts. So scientific method as advertised is a means of conducting useful investigation, but it's not the only way. Which brings us to:

"Newtonian mechanics are NOT a description of the workings of the universe; they are a model, a best guess approximation of observable phenomena so we can make predictions. In fact, they're usually quite incorrect: it's just that the predictions they make are good enough for the level of precision required.

A (ridiculously) sufficiently detailed model of, say, me throwing darts at a board might be able to accurately predict exactly where each dart I throw will go, but such a task is herculean in effort and pretty much worthless."


As previously stated, Newton wasn't interested in describing the workings of the universe. He was interested in quantifying those workings, for practical use by man. And he did describe those workings well enough that they were sufficient for the next two and a half centuries. Newton had epistemological biases that contrast significantly with those of the 21st Century. He was satisfied that it was good enough that to know what could be found out. The manic wars over competing theories that characterize much of 21st scientific method would have bemused him. He most likely would have said, "Let's find out what we can, then find out some more, and accept that that which we can't explain will remain inexplicable."

jollyreaper said...

@ milo

You know, I'm getting really tired of the spam filter making it hard for me to tell if my post even made it through.

How are you posting regged? I'm using a google account and it's not having any problems.

Milo said...

Jollyreaper:

"How are you posting regged? I'm using a google account and it's not having any problems."

I don't have an account of any sort. I'm posting "anonymously", using the Name/URL radio button. And I think Blogger has decided I'm a spammer and blacklisted my IP address.

Tony said...

ElAntonius:

"And yes, in the face of sufficiently powerful and capricious beings, we are become as dogs. I still fail to see how that invalidates science..."

If you can't trust the prediction you make today to be valid tomorrow, you cease dealing in science. Scientific predictions have to be reliable. If a god's actions make them unreliable, then they are no longer science.

"In either case, we're far afield of the original point...The thing I was originally responding to was 'like our world, but some people can waggle their fingers and make fire out of nothing'."

But I jumped in when the assertion was made that science could still proceed in a world where physical reality was changed in some significant way. If it could happen once, then it could happen again, which would invalidate all of science.

"Also, do you own pets? Most pet owners will tell you that pets are quite adept at reading our cues...their information about their owners is far more reliable than you might think."

I've shared my life with many dogs and cats. (I dislike the idea of "owning" pets. I understand that ownership is a necessary legal fiction, but the actual relationship between the individual creatures in question is one of partnership. I even feel that way about meat animals. And I'm not a PETA freak...I love me some meat.) They are quite good at manipulating their environments on the basis of the information they have. It's a standing joke in my family that my dad's Lab/Golden mix was smarter than he was by the only measure that counted: he did what she wanted, not the other way around. Still, domestic animals, even the most highly valued and well-catered-to, do not live in an environment of predictable physical reality. Any cause and effect relationships they perceive in their treatment by humans is totally dependent on human whims and circumstances not changing. That's not the samw thing as Newtonian mechanics, whcih are always valid, everywhere, within the limts that they are acceptable accurate.

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