Monday, June 4, 2012

The Last Battleship

Over the Memorial Day weekend, USS Iowa left San Francisco Bay, presumably for the last time,on its way to become a historical exhibit in, apparently, San Pedro. (She should have become a historical exhibit here, in San Francisco. That she didn't is a travesty for which the political side I generally agree with was to blame, but has roots in an episode that was not the Navy's best moment. See the Wikipedia page on the ship. But watching her leave was a rather moving experience I otherwise would not have had.)

I am not sure in what sense Iowa is the 'last battleship.' It does not seem to have been the very last in commission, but more likely was the last to be 'striken' from the navy list. This came after it rusticated for some years in the Suisun Bay mothball fleet, out of commission but at least nominally available for refurbishment and return to service. (In fact, it seems that even as a museum ship it is in some theoretical sense still available. But its next berth will almost certainly be its last.)

By exquisite coincidence Iowa passed under the Golden Gate Bridge on the day before the bridge's 75th anniversary celibration, and also happened to coincide with the commemoration of Memorial Day, the 'Murrican counterpart to Remembrance Day.

It all lends itself to any number of reflections. Swords and plowshares: After a lifetime of honorable service (70 years since launch, less a few months), Iowa is headed for a twilight afterlife as a waterfront exhibit, while the bridge remains a major regional traffic artery.

The transience of grandeur: The battleship era still conveys a powerful image, but it was remarkably brief, and Iowa's career belongs almost entirely to its epilogue. None of its class was ever seriously tested as a battleship, i.e. in action against enemy battleships.

In World War II the Iowas were used primarily as carrier escorts. During the Cold War era they were periodically recommissioned for offshore fire support. Functionally they were no longer capital ships, though size and impressiveness certainly qualified them for maintaining a presence, one of the most fundamental naval missions.

The first battleship is considerably harder to identify. The last generation of sailing 2-deckers and 3-deckers were called 'line of battle ships' in place of the older 'ships of the line.' But this usage disappeared when ironclads came along.

The first generation of ironclads had an amazing variety of armament layouts and general configurations. No one knew what the capital ship of the future would be like, which gives the era a wonderfully steampunkish flavor. Russia's Admiral Popov was a radical design even for the era, but shows how unsettled the design possibilities were.

By the 1880s the more bizarrely creative designs were set aside. A relatively standard type of capital ship emerged, exemplified by HMS Royal Sovereign, laid down 1889, and the term 'battle ship' came into use to describe them.

Today we mainly know them as pre-dreadnoughts. Let us pause to admire the meta-ness of that term. Pre-dreadnoughts ruled the waves for a generation, but for nearly all of that time absolutely no one thought of them as 'pre-dreadnoughts.' Our ideas about these ships are inevitably filtered through their successors, and for half the battleship era retrospective time flows backward.

The last engagement between battleships - there were never very many - was Surigao Strait in 1944, so that the battleship era lasted just 55 years. If we take Pearl Harbor as the end of battleship supremacy, 52 years. Thus the battleship epilogue, exemplified by Iowa's career, lasted considerably longer than the battleship era itself did.

In fact the battleship era was transitory, not really an 'era' at all. This may be kept in mind when thinking - and most of you are inevitably thinking - of battleships' possible future spacegoing counterparts. Relatively short periods can stand out in our minds and become nearly timeless 'eras,' when in fact they only lasted a few decades.

That said, in an an age of post-industrial technological maturity the overall configuration of capital vehicles might be as stable as it was in the age of sail.

Capital vehicles - how is that for a colorless expression? I have argued before in this blog, more than once, that the familiar and time-honored naval analogy may be misleading when it comes to space forces. Laser stars, as I have speculated about them, have only a fairly tenuous similarity to 'battleships.' If kinetics are dominant, the platforms from which they are deployed might be even more remote from the battleship image.

On the other hand, the similarities might turn out to be greater, if only because impressive weapon systems have power-political significance that extends well beyond their purely military characteristics.

Discuss.




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My phone camera image of Iowa passing under the Golden Gate Bridge was too low-res to be worth posting. The Tumblr image above comes from this naval history page.

1,169 comments:

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kedamono@mac.com said...

I don't know if we will see a return to single purpose ships. Now in a Rocketpunk universe, I'd expect to see such a vessel constructed, if not on the ground, then in orbit. A massive cylinder, sporting all sorts of weapons peculiar to the rocketpunk genre. It would be basically a moving battlestation, because something that big doesn't move very fast, very quick unless you put huge atomic drives on it.

In fact battlestations, orbital platforms with tons of armor and outsized weapons would be present. They would be sitting ducks, but still, they would take down 10 times their mass in attacking ships before they get reduced to slag.

But in the near future, I don't see purpose built warships. I see modular vehicles that can be reconfigured and altered for different missions and tactics. Need to suppress a colonial rebellion on Mars, add two or three missile pods to the ship with kinetic impactors. Fire them up to several Ricks worth of damage and rebellion solved.

Armor may become obsolete since to carry more armor requires more reaction mass and more reaction mass means the ship costs more to operate and you either have one large tank (Target painted on side) or multiple smaller tanks (More mass to haul around). Yes you'd need some "directional" Whipple Shield armor for pesky grains of dust, but more than that eats into your delta V and limits your ship as to what it can do before it ends up on a cometary orbit with empty tanks.

Tony said...

Excellent nostalgia, Rick. During The War, one of my grandmothers worked at Mare Island Naval Shipyard as a welder. (On new construction submarines, however, not battleships.)

One slight quibble... Even though the battleships in their last incarnation never fought against other ships, they were equipped to do so. They carried 16 Harpoon anti-ship missiles apiece, and those Tomahawk ABLs (Armored Box Launchers) could be outfitted with anti-ship versions of the cruise missile. Also, they could have absorbed a considerable degree of punishment from any enemy anti-ship missiles that got through.

In any case, I think the fascination with the battleship era -- and I think it's right to call it an era, however short-lived -- goes beyond the obvious gigantism and romanticism. Battleships were very interesting applications of technology in their own right. Now, while I think that people who get lost in the minutiae of guns vs armor are misguided, I find study and discussion of the ship's as technoloigcal systems endlessly fascinating. Carriers and destroyers, not so much.

Brett said...

Does the Midsize Insider have its own separate feed for your stuff there?

In any case, I think all warships operating on an inter-planetary range (or greater) will be "Capital Vehicles", simply because of the engine and fuel requirements. Your space stations/command ships might carry smaller craft to be used in a near-planetary, near-asteroid colony, or near-space station environment.

I disagree with Kedamono in thinking that they'll specialize. The "laser stars" providing anti-kinetic, anti-missile, and anti-ship screens for your command station are going to have some very different engineering requirements than the ones you might need for the ships that are basically engines and fuel bags attached to remotely and/or autonomously controlled missile pods.

@Kedamono
Need to suppress a colonial rebellion on Mars, add two or three missile pods to the ship with kinetic impactors. Fire them up to several Ricks worth of damage and rebellion solved.

Not necessarily. Committing genocide to put down rebellions isn't publicly acceptable now, and that's been a solid evolution in world public and cultural outlook over time. I doubt it will be more acceptable at any time in the PMF.

Instead, you need to move a station into orbit over Mars so that you have space-to-ground superiority, and can land the troops necessary to quell the rebellion (with air and orbital support). Only the Martians have a defense fleet of their own, a big set of telescopes on Phobos, and a big laser that uses Deimos's rock as a heat sink.

Cheery Reaper said...

I dunno, terms to evolve and stick around, the modern destroyer doesn't resemble its ancestor very much for example. And today's Armored Cavalry is nothing like the Roman Cataphract, but its still called cavalry.

I think that Battleship would be a perfectly legitimate name for a big-ass inter-planetary range warship with heavy armor and heavier guns than most ships are able to provide power for.

As for armor. . . I think that after the first highly expensive and unarmored - if they are unarmored - warships melt when they get hit by a railgun round and their highly trained crews die with them, the powers that be (and the companies building the ships and the politicians they back) will decide that armor that can protect your investment and the crew is worth the reduced range that the ship will have.

Cheery Reaper said...

I dunno, terms tend to stick around, the Frigate doesn't bear much resemblance to the one of Horatio Nelson's day and the Destroyer doesn't have much in common with its ancestor anymore, Armored Cavalry is nothing like the Alae, yet we still call them by those names.

And I think that Battleship is a perfectly legitimate term for a big-ass, heavily armored, inter-planetar range warship with plenty of juice for larger caliber and more powerful weapons than other ships.

As for the question of armor, I can see that playing out like so (assuming someone launched a highly expensive and unarmored warship):

Shipbuilder's vessel is slagged the first time out and the company and the politicians they back come under fire and the company and their politicians don't want to lose one of their expensive investments and so install heavy armor on the ships and never mind the reduced range.

Meanwhile, the families of the crew killed on the first unarmored ship have funerals to attend.

Anonymous said...

I actually think the Space Battleship is unlikely.

I think that ships will be designed very specifically for whatever mission they carry out.

And the big fleet action combat specialist will only be as big as it needs to be to mount the most effective weapons system(s).

So to put it in perspective of the 1930's tech it would be a destroyer sized ship with one 16" gun, and some torpedo tubes.

Because space craft simply wont be able to mount enough armor to survive being hit over and over like a battleship could in WW2.

If its SCODs and 1 light-second lasers, it will have a decent SCOD delivery system and one 1 1ight-second laser.

If you want massed firepower you'll have more ships.

(SA Phil)

Cheery Reaper said...

Because space craft simply wont be able to mount enough armor to survive being hit over and over like a battleship could in WW2.

Why is that?

Sabersonic said...

DeltaV most likely, Cheery Reaper

Anonymous said...

DeltaV is the big one, The Battleship needs to carry reaction mass to do anything. It can't push against space like a seagoing Battleship can push against the water with its propellers.

But there is also the impact energy problem of kinetics.

A battleship in World War 2 was hit by slow poke projectiles.

In a space conflict kinetics will be hitting at hyper-velocity.

Quoting wikipedia for a moment..
================================
The term hypervelocity usually refers to a very high velocity, approximately over 3,000 meters per second (6,700 mph, 11,000 km/h, 10,000 ft/s, or Mach 8.8). In particular, it refers to velocities so high that the strength of materials upon impact is very small compared to inertial stresses.[1] Thus, even metals behave like fluids under hypervelocity impact. Extreme hypervelocity results in vaporization of the impactor and target. For structural metals, hypervelocity is generally considered to be over 2,500 m/s (5,600 mph, 9,000 km/h, 8,200 ft/s, or Mach 7.3). Meteorite craters are also examples of hypervelocity impacts.
============================

Basically these Kinetics will be better than any armor piercing canon shell.

So the space battleship will need armor that is far more effective than the Earth Battleship's

High Energy Lasers provide a similar problem.

Essentially in any non operatic or even demi-operatic sense any spacecraft can only reliably survive by avoiding being hit. Much like a modern fighter plane.

Even the capital ships will have the survivability of "fighter planes" (minus active defenses).

(SA Phil)

Daniel said...

The way I expect it to go is for there to be 4 types of ships: laser-stars, kinetic-stars, CnC ships, and tenders. Laser- and kinetic- stars will be unmanned and barely, basically remass tanks wrapped around weapons and engine. CnC and tenders, with their more valuable cargo (people and oxygen, respectively) will have more defenses, though the only real defenses they'll have is not being there when lasers punch through space and shooting down any incoming missiles (laserstar's job). Even without a real battleship role here, naval ones fit well. Its more like flagship, escorts, PT boats and tenders.

FBH said...

To be honest, what you're seeing partly here is also the problem with modern naval nomenclature. Basically right now, combat surface ships that fight with their own weapons are being named whatever the builders think sounds cool.

Back in WW1/WW2, there was an extraordinary diversity in surface ship roles. These roles have in many ways actually vanished today.

You had destroyers who's job was variously to shoot it out with enemy torpedo boats, and then to basically replace large ocean going torpedo boats and provide general escort services.

You had light cruisers who's job was to variously scout, shoot at aircraft, or act like destroyers but with better range and sea handling. Heavy cruisers who's job was scout but ended up doing just about everything else but.

Above those you had battleships which carried the biggest guns and carriers which threw aircraft off the deck.

Why was this and why'd it change?

Well partly it was because in WW2 the state of weapons was in flux. You fought with large guns, or you fought with torpedoes. These required different configurations of ships to handle.

Right now we really only have one type of weapon. The missile. Modern ships are much more multifunction than where WW2 vessels. A ship can specialize in air defence and have a helicopter to hunt submarines.

So in a way we've settled into a paradigm where while we might call them destroyers or cruisers, just about everything is a "battleship." There's likely to be a single (or a few, based around different mission profiles) type of surface combatant platform that does most everything.

All of that said, this is partly an effect produced by the USA's complete dominance of the sea and the end of the cold war. The Soviets did have devices you could plausibly call cruisers or even battle cruisers due to the need to mount gigantic, carrier slaying missiles on them.

Even that however is likely to vanish. Current missiles like the Brahmos, even subject to treaty limitations are smaller faster and pack a similar punch to the old Granits and Moskats. While Russian, Chinese and Indian vessels may not settle on the same kind of design that is used by NATO and friends have they're likely to settle on a platform in the same kind of ballpark tonnage as NATO and friends.

So yes. I think if we have space ships, unless we have a technological base which allows for a set of specialist roles (that seems pretty unlikely in space), you might as well go back to the age of sail. . .

Or just call everything battleships.

*Basically not just a ship based on one weapon, but around one weapon: a single very large VLS array. This VLS carries large numbers of different weapons including SAMs (which are also shot at surface ships) land attack missiles and submarine attack missiles (ASROC).

Anonymous said...

Guns are going to make a comeback though for surface ships.

Or at least a BFG, the 64 MW railgun on the new Destroyer class under development.

I don't imagine the ship will have more than one, though that one will be more than even one Iowa's 16 inch cannons could match.

I expect it will have missiles also to protect it from aircraft and so on.

(SA Phil)

Anonymous said...

Having a large number of relatively small (and cheap), ships with a mix of weapons, sensors, and other combat support systems, will probably be the model used for some time after the first space war. Whether these are modular or purpose-built, I don't see a significant number of huge combat spacecraft being built; if you need more firepower, use larger groups of ships; a flight of two, or a squadron of six, or a group of 18, for example. You can build one 'battleship' or a dozen 'gunships'; you can cover one area, or a dozen...

Ferrell

Brett said...

The problem lies in determining what constitutes a "small ship". If this thing is internally propelled, any hard-ish ship with inter-planetary range is going to be either big or slow. Your ships will also need large radiators if they're hauling around lasers and running with relatively high power consumption.

Besides, large groups of small ships run into coordination issues, particularly when light-speed lag is a significant problem.

Scott said...

"Or at least a BFG, the 64 MW railgun on the new Destroyer class under development.

I don't imagine the ship will have more than one, though that one will be more than even one Iowa's 16 inch cannons could match."

I think the plan is for 2 railguns, actually. Not that we're going to see more than 3 of the Zumwalt-class built.
=====

I'm honestly assuming that the naval nomenclature and culture will come into existence one way or the other, once crew requirements exceed about 15.

Either the USAF will prove utterly incompetent and lose a bunch of officers (forcing the USN to take over), or the USAF will prove to be smarter than I think they are and start adopting some of the naval crew-organization model before they lose a ship.

As far as armor goes, don't forget aerogels. low-mass, but rather effective at dealing with certain types of impacts and energies.

Hugh said...

I suspect really big battleships will still be built in the plausible mid future. Until the fighting actually starts, size and general all-round fearsome appearance have an important symboblic and psychological role: "you don't want to mess with us."

This is perhaps more likely if the space warships and their crews come from a naval culture and doctrine rather than air force. The "line of battle" is well entrenched in naval thinking (and science fiction authors). Robert O'Connell's book "Sacred Vessels" suggests this caused the US Navy and others to consistently under-estimate submarines because they didn't fit into the paradigm. Even after they'd proved what they could do in WWI.

For a historical example, look at the number of dreadnoughts bought by South American and other countries before WWI, most of which were kept in service until WW2 or even after in some cases. And it's probably true that these navies got their money's worth, so to speak, from these awesome symbols even if they never fired a shot in anger.

FBH said...

Rail guns may appear, but they won't bring back armoured big gun ships because the shells are too accurate. It's impossible to armour a ship everywhere and with guided and anti-radiation munitions then a heavily armoured vessel can be relatively easily neutralized.

I actually think the idea of large vs. small space ships is something of a dead end. If we assume things look like modern surface ships then it's more likely you'll get everyone agree on a particular, optimal size of space ships.

So modern surface combatants everyone has 'agreed' that the optimal size is about 8-10 thousand tons. Larger or smaller than that are rare exceptions and secondary units.

papa said...

The Battleship Era is not unique in being an era whose prominence in our cultural memory greatly outsizes its chronological span.

The Cowboy West period of American history inspired still-influential genres of film and literature (see "Bat Durston") and is a prime component of the American identity, but historically only lasted from the end of the Civil War to around 1890, or about 25 years, less than half as long as the Battleship Era.

I suppose it's the way of anything that becomes a legend. King Arthur was
historically was probably no more than a Briton chieftain who had a moment of glory during the ultimately unsuccessful holding action against the invading Saxons, but look how large he still figures in the popular imagination.

Some legends are so significant from their impact on cultural identity and values that the slightness of their historic origin become irrelevant. Examples of this are the divine origin of the imperial dynasty of Japan, which though not widely believed anymore still has an impact on Japanese culture and politics; or Christianity, which
originated in the obscure (though widely believed to be historical) life of a Jewish rabbi in 1st century Palestine, but is the source of Western values and identity.

Rocket Punk is a kind of legend that grew from a fiction without any real history behind it, or at least no more than embryonic history of the early Space Age.

It's easy to pick other examples of legends that are culturally significant but are now know to have been historically insignificant. What about current events that seem historically insignificant but contain the seeds of future legend? It's tough because you have to think against the grain of your own biases and tastes.

* The obscure science fiction subgenre of Rocket Punk is honored as prophetic when the future turns out exactly as Heinlein, Clarke, etc. envisioned.

* We are praised in the future for our foresight in burying large volumes of
plastics in landfills after a method is discovered to process old plastic into cheap energy or other resource.

* The inhabitants of future planet New New York worship Bloomberg the Wise whose laws spurred the evolution of the superhumanly healthy Homo New Yorkensis, allowing it to supplant Homo Sapiens in dominance on Earth and eventually colonize other low-fat planets.

Tony said...

Ferrell:

"Having a large number of relatively small (and cheap), ships with a mix of weapons, sensors, and other combat support systems, will probably be the model used for some time after the first space war. Whether these are modular or purpose-built, I don't see a significant number of huge combat spacecraft being built; if you need more firepower, use larger groups of ships; a flight of two, or a squadron of six, or a group of 18, for example. You can build one 'battleship' or a dozen 'gunships'; you can cover one area, or a dozen..."

Juxtaposed with:

Brett:

"The problem lies in determining what constitutes a 'small ship'. If this thing is internally propelled, any hard-ish ship with inter-planetary range is going to be either big or slow. Your ships will also need large radiators if they're hauling around lasers and running with relatively high power consumption.

Besides, large groups of small ships run into coordination issues, particularly when light-speed lag is a significant problem."


Which is why we'd probably see interplanetary carriers used to move large numbers of scout/attack ships to the planetary orbitals where the actual fighting will take place.

Tony said...

Since this is the most current topic...

Ray Bradbury died yesterday.

Anonymous said...

FBH said...
Rail guns may appear, but they won't bring back armoured big gun ships because the shells are too accurate. It's impossible to armour a ship everywhere and with guided and anti-radiation munitions then a heavily armoured vessel can be relatively easily neutralized.

-----------

I agree.

Also this 64 MW railgun projectile is going to be much faster than any cannon shell.

You would need much thicker armor, similar (but to a lesser extent depending on range) to the hyper velocity point I referenced earlier.

It is going to be like a uber version of the high velocity kinetic armor penetrators used in tank warfare now. M1 tanks really didnt have any trouble ripping through Russian T 72/80 armor.

Which was based on some of the best ideas that came out of the WW2 cannon era.

(SA Phil)

Brett said...

@Tony
Ray Bradbury died yesterday.

It's almost the end of an era. Bradbury was part of that great generation of Science Fiction writers: Isaac Asimov, Arthur C. Clarke, Robert Heinlein, Richard Matheson, Poul Anderson, Frederick Pohl, Brian Aldiss, and Philip Dick. Now only Aldiss, Pohl, and Matheson are left, and all three are 86 years old or older.

@Anon
It's impossible to armour a ship everywhere and with guided and anti-radiation munitions then a heavily armoured vessel can be relatively easily neutralized.

I don't know if I would rule out armor entirely. I remember reading an interesting idea for Reactive Armor 2.0: maneuverable panels that a ship could eject off its outside hull.

I'm not sure what an "anti-radiation" munition is.

Anonymous said...

=Milo=



Brett:

"I remember reading an interesting idea for Reactive Armor 2.0: maneuverable panels that a ship could eject off its outside hull."

Isn't that pretty much a point defense?

You're effectively shooting the incoming projectile down. With a panel rather than a smaller and lighter bullet, which doesn't seem all that useful.


"I'm not sure what an "anti-radiation" munition is."

A missile whose guidance system homes in on radiation sources. Such as communications, RADAR, or engines.

Tony said...

Brett:

"It's almost the end of an era. Bradbury was part of that great generation of Science Fiction writers: Isaac Asimov, Arthur C. Clarke, Robert Heinlein, Richard Matheson, Poul Anderson, Frederick Pohl, Brian Aldiss, and Philip Dick. Now only Aldiss, Pohl, and Matheson are left, and all three are 86 years old or older."

Very uneven roster there. I would only name Anderson, Asimov, Clarke, and Heinlein to my all-star team.

"I'm not sure what an 'anti-radiation' munition is."

Radar-homing

FBH said...

SA Phil.

The problem is you can't armour a ship like that everywhere. Any such ship would be far too heavy.

And if you can, the enemy will just drop a nuclear bomb on it, or destroy it's sensors and communications.

So yeah. No battleships. Not even with rail guns and lasers.

Brett said...

So, no armor then. I don't think that means the end of space "battleships". It just means that they'll depend more on active defenses, ship design, and creating uncertainty in their position if it's a ship-to-ship combat situation.

@FBH
And if you can, the enemy will just drop a nuclear bomb on it, or destroy it's sensors and communications.

That applies to any ship, and the bigger ships have an advantage in that they can carry more equipment for point defense, or have bigger sensors.

Anonymous said...

I can see uncertainty in position on a surface ship - in fact that is part of the DX-100 proposal.

But in a space craft it will be really hard to pull that one off.

A simple IR camera is going to be the bane of every would be Stealth Ship designer's dream.

(SA Phil)

Brett said...

@Anonymous
A simple IR camera is going to be the bane of every would be Stealth Ship designer's dream.

You don't need to perfectly hide a ship, just introduce a fair amount of uncertainty in its position in order to make targeting it much harder. That's not very difficult, especially if the IR telescope is trying to find and track a ship light-minutes out that's smart enough not to fire its engines for more than brief intervals (or fire them in the direction of the target until they absolutely have to slow down).

Modern stealth has the same goal. It doesn't make planes invisible to radar - it just reduces their radar profile, making them harder to track.

Anonymous said...

Couldn't the observing point just extrapolate the ship's position based on the heat radiated from the craft?

Fire the engines .. heat radiates away from the reaction mass. You know how fast the reaction mass is moving ... and thus...

(SA Phil)

Anonymous said...

Using IR sources mounted on drones bobbing around the main ship, lasers, jammers of various frequency ranges, high-powered flares, clouds of floresing gas or dust; long and short duration countermeasures deployed during combat would tend to confuse enemy sensors and fire-control; the object is to degrade it, not necessarily to completely neutralize it. Even the smallist advantage or the briefest distraction could be the difference between victory or defeat, which sounds melodramatic until you remember that such things have been true of combat since humans began organized fighting...

Ferrell

Brett said...

@SA Phil
Couldn't the observing point just extrapolate the ship's position based on the heat radiated from the craft?

Fire the engines .. heat radiates away from the reaction mass. You know how fast the reaction mass is moving ... and thus...


That sounds like something you could spoof with IR emitting drones, particularly if you're smart enough not to do engine burns so long that the enemy telescopes can get enough exposure for a spectographic analysis.

Like I said earlier, you're not trying to perfectly hide your ship. You just need to throw enough uncertainty into your enemy's targeting so that it becomes much more difficult to target and destroy your ships.

Anonymous said...

It seems like it would be very tricky to fool the observer when the observer is close enough to matter. Radiation is a pretty slow way to disperse heat- And an "IR drone" is just short for a "heat drone"

How are you going to have a similar enough heat profile for a "battleship" space craft with just a drone? Wouldn't you have to assume a low level of resolution?

If the decoy is too hot (temperature wise, in order to create a lot of heat) the computer will be able determine the difference with a vision system. And if it cant, it can label all the heat sources and the crew probably can.

I don't know why you need spectral analysis either - real time heat cameras exist now. Once the observer knows whats coming it and generally where- it can just focus in.

The thing about an engine burn is the heat will last much longer than when you are burning. The heat from the reaction mass stream, the heat from the engine nozzle, the heat from the radiators, etc. It will all radiate in a predictable way at a known speed. You should also be able to estimate heat conductance along the spacecraft parts and use that temperature gradient to help identify it.

Also I see a potential problem even if the IR decoys work. The Battleship will need to keep them nearby -- in order to obscure its own heat (mainly the reactor waste heat on the radiators even when not thrusting)

But if the decoys are close then the cloud of KKVs will all be headed for the same general area, and the Battleship point defense will have no choice but act - because it wont know exactly where the KKV will hit with such a tiny vector difference.

Once the Point Defense starts firing- it might as well be an engine burn.

(SA Phil)

Byron said...

I remember posting somewhere about the space fighter era (the theory was that early warships would be space fighters as they're easier to make then full-scale vessels) and that it would likely be romanticized. I would argue that the battleship was not transitional, as it was the ultimate development before aircraft.

Tony:
Which is why we'd probably see interplanetary carriers used to move large numbers of scout/attack ships to the planetary orbitals where the actual fighting will take place.
Heresy. You should know better then to advocate space fighters after all the times we've been over this.

Armor would actually be quite useful. While it is unlikely to be enough to totally protect against main kinetics, enough armor to protect against fragments and long-range lasers is totally feasible and even required.

Also, are we really going to go to "stealth in space" again?
The simple fact is that the enemy will know you are there and roughly where you are going. Any evasive tactics are going to make him more interested in you. And by the time he's closed to weapons range, he should have a good idea of where and what you are.

Ken Burnside said...

I actually have problems with targeting ranges assumed to be easy in this blog's posting. Not detection ranges, but targeting ranges.

It is fairly easy to determine the diffraction distance of a laser given the wavelength, mirror size and known properties of mirror making materials.

It is absurdly easy to detect targets in space (to quote another poster, "Oh god, not stealth in space AGAIN!")

What it is NOT easy to do is both hit a target with a high energy, short wavelength laser beam past about 2 light seconds AND keep that beam "on target" long enough to do anything. Differential expansion of the material used to make the beam-guide and focusing optics is already a problem with the Hubble, and the Hubble isn't trying to put a UV laser (with all the attendant vibrations of a power generation and active heat sink management system added on.)

While 2 light seconds is nothing in interplanetary distances it does mean that anything resembling tactical maneuver matters less in this kind of combat than it does in modern surface naval combat. This does make me sad, because games of maneuver (and fiction about maneuvering units) are much more compelling to me.

Tony said...

Byron:

"Heresy. You should know better then to advocate space fighters after all the times we've been over this."

Hehe...

Space fighters are only heresy where tactical and strategic propulsion comes out of the same engine -- the battleship era. When it doesn't you get carriers and subordinate attack craft -- all of the time since. (Fighters actually exist to protect the carrier and the attackers; they don't exist for their own sake, despite what fighter pilots believe.)

There's not one shred of evidence on which to conclude that space will be any different, in that respect. Application details may be different, but the carrier/attacker division of labor is based on pure physics -- here on Earth as much as it will be in space.

Byron said...

Ken:
I would agree that multiple light-second ranges are probably out. Even then, something on the order of half a light-second is probably achievable, which is still quite a lot.

Tony:
Space fighters are only heresy where tactical and strategic propulsion comes out of the same engine -- the battleship era. When it doesn't you get carriers and subordinate attack craft -- all of the time since. (Fighters actually exist to protect the carrier and the attackers; they don't exist for their own sake, despite what fighter pilots believe.)
I realized all of that some time ago. The problem is that there is no medium change which conveniently allows fighters to work today. Thus, you either need some fighter-specific engine (special pleading) or a specific operational role.
The problem with the idea you outline is that the carrier is a single point of failure. The enemy has no reason not to attack it before it launches its parasites, whatever they may be called. If there is (say that it's a patrol carrier sent to a balkanized region or some such) then it becomes more practical. As a primary battle fleet, not so much.

There's not one shred of evidence on which to conclude that space will be any different, in that respect. Application details may be different, but the carrier/attacker division of labor is based on pure physics -- here on Earth as much as it will be in space.
Exactly. I've recently been working on a paper on space warfare, and the first section is on fighters. I'll allow it to serve as my rebuttal.

Eth said...

What I wonder is how easy will it be to blind enemies instead of damaging them, with lasers. You don't have to be as focused to damage any optical equipment pointed at you, meaning that you can blind enemy ships from far longer, and use simpler, smaller, less powerful and/or of lower wavelength than to cause damage.

Of course, blinding would last only the time for the ship to change damaged equipments and affect only the equipment pointed right at said ship, but it could slow their target acquisition long enough for you to get a shot at them (but not to flee, however).
In fact, at some point space battles may be won by the side who has the most replacement telescopes and/or who used them the smarter.
It may also be effective against long-range missiles if they have limited replacement optics.

There are other sensors than optical, of course, but there would probably be other counter-measures to those.


I can see the equivalent of a 'battleship era' in space, but probably with far more emphasis on the hardware effectiveness than on the tactical skills of their commanders.
There would probably be periods, like the 'laserstar era' where everyone build bigger and better laserstars (maybe with support crafts), until someone finds how to render them obsolete.
They may be romanticized afterwards, though, with far more emphasis on the hotshot laserstar pilot, while in reality they were technical operators, and there may even have no major conflict.

Tony said...

Byron:

"I realized all of that some time ago. The problem is that there is no medium change which conveniently allows fighters to work today. Thus, you either need some fighter-specific engine (special pleading) or a specific operational role.
The problem with the idea you outline is that the carrier is a single point of failure. The enemy has no reason not to attack it before it launches its parasites, whatever they may be called. If there is (say that it's a patrol carrier sent to a balkanized region or some such) then it becomes more practical. As a primary battle fleet, not so much."


Carriers have always been single points of failure. Just ask the Japanese and Americans, who both lost significant numbers of them in combat. That alone doesn't invalidate them. Besides, it's not like one needs only a single carrier for a given operation.

"Exactly. I've recently been working on a paper on space warfare, and the first section is on fighters. I'll allow it to serve as my rebuttal."

You'll need to seriously revise it if you want to be accurate.

First of all, you are mistaken in presuming that there would even be such a thing as deep space fighter combat. Even at the height of WW2 naval combat in the Pacific, fleet engagements happened in association with amphibious campaigns against this or that island. And they generally happened within a few hundred miles at most of those island objectives. So, the valid analogy would be that parasites (using your terminology) are the tactical elements for fighting in and around planetary orbitals, while carriers are the strategic transportation means between planets. (FTL carriers being able to change which solar system they are in, but otherwise still carrying parasites to fight in and around planetary orbitals.)

So, taking the orbital roles of the parasites as given, one eliminates the need for the 4x energy expenditure coming and going. The parasites get to use gravity to turn them around and come back after a mission. And they can get their initial velocity from the carrier, which starts (or continues) to decelerate after parasite launch, into a safer, further orbit. (it's also a much higher altitude orbit, which makes it hard for defenders not already there to reach with effective countermeasures.

Where does that leave us...oh, yeah -- perceived utility. If one doesn't presume laserstars and light-second range lasers a prior -- and I wouldn't -- then parasites obviously take whatever weapons are in use to where they can do some good, use those weapons, and return for a reload/refuel.

Also, the fighters can be on the other side of the planet from the carrier(s) when a real-time decision needs to be made now, not several radio relays and light seconds of time away in distand orbit. Drones can't answer that requirement.

Anonymous said...

Part of the problem is that there are so many undefined variables.

Propulsion system: undefined
Realistic Mass ratios of Space Craft: undefined
Spacecraft Reactors: undefined
Closing ranges: undefined
Closing speeds: undefined
Weapon System 1 Effective range: undefined
Weapon System 2 Effective range: undefined
Mass of armor: undefined
Effectiveness of armor vs weapon system 1: undefined
Effectiveness of armor vs weapon system 2: undefined
Mass penalty of armor for weapon system 1: undefined
Mass penalty of armor for weapon system 2: undefined

Mission parameters: undefined
Required DeltaV to meet Mission parameters: Undefined
Benefit of High Thrust vs High ISP visavis Mission Parameters: Undefined

Everyone probably has different ranges in mind for all these varaibles.

But without setting those ranges a little bit one person's assumptions are another persons implausibility.

(SA Phil)

Anonymous said...

Byron,

The enemy has no reason not to attack it before it launches its parasites, whatever they may be called.

==========
Unless there is some reason it can't.

Essentially the carrier seperated from the parasites outside of the opposing force's effective range.

Call it a Hisp ISP Tug and a bunch of high thrust Parasites.

It assumes there is some advantage to
A) Smaller ships arent as easy to mission kill as Larger ships due to numbers
B) High thrust is some advantage in the combat environment.

Otherwise the parasites might as well just perform the whole mission themselves without the tug.

Another possibility is the Tug has a spin hab and a lot more propellant than the parasites. But propulsion types are similair.

The seperation is just for combat survivability purposes.


(SA Phil)

Tony said...

SA Phil:

"Essentially the carrier seperated from the parasites outside of the opposing force's effective range.

Call it a Hisp ISP Tug and a bunch of high thrust Parasites."


If you presume there is no such thing as deep space combat, just combat in planetary orbitals, this seems like the natural division of labor.

"It assumes there is some advantage to
A) Smaller ships arent as easy to mission kill as Larger ships due to numbers"


An inherrent advantage to numbers, all other things being equal.

"B) High thrust is some advantage in the combat environment."

If we're presuming orbital combat and a real performance dichotomy between strategic (i.e. interplanetary) and tactical (i.e. orbital) propulsion, this seems obvious. If you need to change your orbital altitude in combat, you need to do it now, not a week from now.

"Another possibility is the Tug has a spin hab and a lot more propellant than the parasites. But propulsion types are similair."

With similar propulsion types you have the man-o-war era -- a range of sizes, but essentially a continuum of size, not a hard division.

jollyreaper said...

Part of the problem is that there are so many undefined variables.

But without setting those ranges a little bit one person's assumptions are another persons implausibility.


That's the long and the short of it right here. Any given scifi setting is one person's answers to all of that.

This is why I'm a fan of inventing new terminologies for new ships, just to break with the built-in bases of the past.

Just as an example:

S/A: Scout/Attack, smallest and fastest ships

H/K: Hunter/Killers, middle-weight with fangs and endurance.

Capital Ship: Biggest ship size, most expensive, most survivable.

You can kind of get an idea of how this fleet works without even mentioning bean one about the underlying technology.

I'll mention two other things worth considering:

Competitive Balance from TV Tropes. Really helps to get your mind thinking about the idea for combat ships. Fragile speedster, glass cannon, mighty glacier, stone wall, lightning bruiser, jack of all stats.

The goal for any designer is a lightning bruiser -- strong in attack, defense, and speed. A jack of all stats design aiming for balance might be blessed with suck.

Finally, consider the Standard scifi fleet.

Enough grist for discussion. :)

Brett said...

@SA Phil
It seems like it would be very tricky to fool the observer when the observer is close enough to matter. Radiation is a pretty slow way to disperse heat- And an "IR drone" is just short for a "heat drone"

If you've thrown a ton of confusion as to where the incoming fleet is going to be until they're relatively right on top of you (i.e. a few hundred thousand kilometers out), then that's time and space they can't effectively use to defend far out from home.

How are you going to have a similar enough heat profile for a "battleship" space craft with just a drone? Wouldn't you have to assume a low level of resolution?

Millions of kilometers out, your ship is just going to be a glowing hot dot among other hot dots even if you're using IR telescopes hundreds of meters across. You won't have great resolution until they're much closer.

I don't know why you need spectral analysis either - real time heat cameras exist now. Once the observer knows whats coming it and generally where- it can just focus in.

But at the light-minute range, you're actually just focusing where the ship might have been a minute ago, or two minutes ago.

The thing about an engine burn is the heat will last much longer than when you are burning. The heat from the reaction mass stream, the heat from the engine nozzle, the heat from the radiators, etc. It will all radiate in a predictable way at a known speed.

How are you going to tell the direction in which it's radiating, and separate a ship from a drone that's just blasting out heat designed to make it look like a ship?

Also I see a potential problem even if the IR decoys work. The Battleship will need to keep them nearby -- in order to obscure its own heat (mainly the reactor waste heat on the radiators even when not thrusting)

I don't think the decoys are supposed to "swamp" out the heat of the battleship. They're just there to catch the attention of the telescopes and systems behind them.

@Ken Burnside
It is absurdly easy to detect targets in space (to quote another poster, "Oh god, not stealth in space AGAIN!")

I'm going to push back against that. Exactly how is it easy to detect a pixel's worth of infrared light against a sky, identify where it is and where it's going light-minutes after the fact, and then determine that it's a potential enemy versus the other ships that an interplanetary or interstellar civilization is going to have flying around its own solar system? Especially when the enemy is doing things to try and make it more difficult for you in terms of detection in targeting, like mostly drifting with occasional short engine burns, and possibly launching decoys?

Sure, once it's up real close, you can't hide anymore - but now it's up real close, and you can't send out ships to engage the enemy at a distance.

Heresy. You should know better then to advocate space fighters after all the times we've been over this.

In orbit, they make some sense, although they'd probably just be drones.

Tony said...

jollyreaper:

"The goal for any designer is a lightning bruiser -- strong in attack, defense, and speed. A jack of all stats design aiming for balance might be blessed with suck."

Where military vehicles are concerned, the standard three degrees of freedom in design trade-offs are firepower, protection, and propulsion. What you desire is a design where nobody has to trade anything off. Unfortunately, it's not plausible. One has to trade some propulsion and protection for maximum firepower, or maybe a significant fraction of propulsion to achieve extra protection and firepower. One can't have all three.

Byron said...

Tony:
Carriers have always been single points of failure. Just ask the Japanese and Americans, who both lost significant numbers of them in combat. That alone doesn't invalidate them. Besides, it's not like one needs only a single carrier for a given operation.
Exactly. This is a rebuttal how? There are advantages to naval air power that outweigh the drawbacks. The same isn't necessarily true in space.

First of all, you are mistaken in presuming that there would even be such a thing as deep space fighter combat. Even at the height of WW2 naval combat in the Pacific, fleet engagements happened in association with amphibious campaigns against this or that island. And they generally happened within a few hundred miles at most of those island objectives. So, the valid analogy would be that parasites (using your terminology) are the tactical elements for fighting in and around planetary orbitals, while carriers are the strategic transportation means between planets. (FTL carriers being able to change which solar system they are in, but otherwise still carrying parasites to fight in and around planetary orbitals.)
Orbital fighters were mentioned at the end of the section. I did deep space first because it's an easier environment to analyze. However, you're still ignoring the critical fact. The fighter can't win against the big ship. PT boats were better close to the coast then bigger ships were. Does that mean there were PT boat carriers? Not after the first time it was tried. Similarly, why is the parasite superior in battle to a bigger ship? It can move faster, but I submit Standard Type logic here. How fast you are doesn't really matter. Threaten something important and force your enemy to give battle.

Also, the fighters can be on the other side of the planet from the carrier(s) when a real-time decision needs to be made now, not several radio relays and light seconds of time away in distand orbit. Drones can't answer that requirement.
Not this again. Give me one concrete example of this situation.

Also, the presumption of no deep-space combat seems hasty. It would make sense to launch missiles at the carrier as early as possible. It wouldn't be fleet-to-fleet, but it would be there.

Byron said...

If you've thrown a ton of confusion as to where the incoming fleet is going to be until they're relatively right on top of you (i.e. a few hundred thousand kilometers out), then that's time and space they can't effectively use to defend far out from home.
The amount of confusion you can generate is fairly minor. It's like throwing a smoke grenade every few minutes at best. They know where you are and where you're going. Just not exactly how many of you there are, but even then, careful observation can get a rough estimate. And that's plenty for an intercept.

Millions of kilometers out, your ship is just going to be a glowing hot dot among other hot dots even if you're using IR telescopes hundreds of meters across. You won't have great resolution until they're much closer.
That's not the problem. The temperature and power output have to be at least roughly the same. That's an expensive drone.

But at the light-minute range, you're actually just focusing where the ship might have been a minute ago, or two minutes ago.
The ability to change position is negligible at the scales in question. You probably won't move a pixel off expected position no matter how hard you burn.

I'm going to push back against that. Exactly how is it easy to detect a pixel's worth of infrared light against a sky, identify where it is and where it's going light-minutes after the fact, and then determine that it's a potential enemy versus the other ships that an interplanetary or interstellar civilization is going to have flying around its own solar system? Especially when the enemy is doing things to try and make it more difficult for you in terms of detection in targeting, like mostly drifting with occasional short engine burns, and possibly launching decoys?
With enough computer power, not terribly difficult. And things like decoys just make it easier. If something is light-minutes away, then there's plenty of time for a leisurely sky search. And you assume that the other person has only one telescope position. That's likely to be false, too.

Anonymous said...

If scout attack size drones make sense the Zeroth law suggests so do scout/attack manned craft.

I don't buy the 3 second improved reaction time thing though - Unless engagement ranges are very short.

But if engagement ranges are very short - you wouldn't need the CIC ship to be several light seconds away ...


---------
I personally think the entire fleet action might not have a single human in any of the combatant craft. All Drones. In all scenarios.

But that would only make an interesting story for a very tiny segment of an already niche hard Sci Fi group.

(SA Phil)

Anonymous said...

If the decoy has:
near the same temperature
near the same heat output
near the same heat radiation profile
near the same exhaust velocity

It will need to have near the same mass..

Otherwise it will accelerate/change velocity much faster than the Battleship and you can distinguish between the targets using the Doppler effect.

Also if it is light minutes but your effective range is less than one light second - then it really doesn't even matter which heat source is the enemy ship. Since you wont be firing on this closing heat dance anyway.

You will just fire at less than one light second where you have more resolution.

Unless you have true vehicular torpedoes (missiles with the same propulsion and endurance of your warship) there is probably no advantage to firing at some massive standoff range where your missile won't benefit from your own deltaV to increase closing speed.



(SA Phil)

Anonymous said...

I'm almost sorry I brought it up...however, you people are arguing that sensor confusing methods won't work at stupid-far ranges, and so won't be used and have no (or very little) utility: what you don't seem to understand is that they won't be used in such situations, except by incompatent commanders; these are ment to be used while actually IN combat, as a method of degrading targeting sensors. An IR decoy drone isn't just a 'heat drone' ; it's more of a high-powered spotlight with a very acurate targeting system. You don't need to damage sensors, but just to overwhelm them.

Also, why do you think that aerospacefighters can't take out capital ships? it's not like they're gonna shoot them with their onboard lasers; they're gonna fire anti-ship missiles at them and nuc 'em. Besides, a pilot could decide to nuc the funny little ship the capital vessels are guarding instead of persuing their preprogrammed attack profile.

The one thing that I an sure of, when it comes to space warfare, is that there will be aspects about it that we all will have had gotten wrong.

Ferrell

Anonymous said...

Sorry Ferrell I was arguing against decoys that could confuse you in the sense make you hard to make out from the drones.

And IR spotlight/diffuse laser fired directly at the observer within a reasonable range sounds a lot more plausible.

(SA Phil)

Byron said...

Ferrel:
Also, why do you think that aerospacefighters can't take out capital ships? it's not like they're gonna shoot them with their onboard lasers; they're gonna fire anti-ship missiles at them and nuc 'em. Besides, a pilot could decide to nuc the funny little ship the capital vessels are guarding instead of persuing their preprogrammed attack profile.
Aerospace fighters? I must have missed that. My point was that a space fighter has no advantage over a bigger ship. Aerospace fighters work, but why not just put a first stage on the missile instead? It's probably only marginally more expensive, and that assumes that the aerospace fighter never gets killed. Not to mention the other disadvantages involved with a spaceplane, like having to base and maintain the thing. It's possible, but they have no advantage over missiles.

Anonymous said...

=Milo=



Eth:

"There are other sensors than optical, of course,"

Name some, please?

You can have infrared sensors, visible light cameras, RADAR, etc., but those are all forms of electromagnetic radiation.

I can't think of any other sensor that could work in space, short of a magitech FTL sensor.



Jollyreaper:

"The goal for any designer is a lightning bruiser -- strong in attack, defense, and speed. A jack of all stats design aiming for balance might be blessed with suck."

A lightning bruiser is simply a jack of all stats that's been levelled up. (To use RPG terminology, which is reasonable if you're talking game balance terms.)

It stands to reason that a much-higher-tech spaceship could indeed have more zapping power than the glassiest cannons from a lower-tech civilization, better armor than any stone walls or mighty glaciers the lower-techies can field, and able to run circles around even what the lower-tech civilization considers fragile speedsters, all at the same time. Thus, that spaceship would be a lightning bruiser as far as the lower-tech civilization is concerned. However, it wouldn't be a lightning bruiser from the point of view of the higher-tech civilization - they can build something that's even more optimized for one of the three attributes, if they want to.



Ferrell:

"these are ment to be used while actually IN combat, as a method of degrading targeting sensors. An IR decoy drone isn't just a 'heat drone' ; it's more of a high-powered spotlight with a very acurate targeting system. You don't need to damage sensors, but just to overwhelm them"

I'm not sure why you need a drone for this though. If your goal is to dazzle sensors, rather than confuse them with decoys, then you could just as well accomplish that with lasers onboard your capital ship.

Fun tactic: fire some kinetics at the enemy, then dazzle their targetting sensors at the critical moment to keep them from stopping the incoming kinetics with point defenses.

Anonymous said...

Kind of butchered the way I worded that last one-

Basically,

I don't buy that decoys can allow you to play a shell game of "which one is the ship" even momentarily, at a useful range.

I do buy the idea of a "decoy" poking a thermal camera sensor in the eye with a heat wave.

(SA Phil)

FBH said...

Brett:
That applies to any ship

Right, which is why you have more ships of optimal size rather than a single, large target that can be taken out by a nuclear weapon.

and the bigger ships have an advantage in that they can carry more equipment for point defense, or have bigger sensors.

Not under current assumptions.

For one thing there has so far never been a point defence missile kill under modern conditions. The closest we came was a British destroyer knocking down an Iraqi silkworm that had already missed. The idea that incoming missiles are defeated by point defence is a bit of a Clancy invention. Actually the defence is a combination of jamming, chaff and manoeuvre.

The ship activates its jammers and deploys chaff, then makes a series of rapid manoeuvres, designed to make the missile miss.

Also there's the question of how much point defence do you really need? A Burke or a Sejong the Great class carry eighty air defence missiles each. There's a point of diminished returns with a single platform.

As for sensors, those are honestly best mounted on some kind of aircraft to account for the earth's curve. The type 45 has a big retarded looking wizards hat on it but I think longer term you'd be better off us to give all ships their own UAVs for sensor coverage.

jollyreaper said...


A lightning bruiser is simply a jack of all stats that's been levelled up. (To use RPG terminology, which is reasonable if you're talking game balance terms.)


Yeah. It's a relative thing. There's the general idea of punching at or above your weight. A medium tank that can't defeat another medium tank's armor seems pretty weak. A light tank that can defeat a heavy tank's armor seems pretty badass. If the average speed of tanks is 12mph, a heavy-hitter with great protection that can do about 11mph is seen as pretty balanced. If it can only manage 4mph, then it will be seen as too slow to be tactically effective. But if the average speed makes it up to 40, then the formerly balanced heavy-hitter becomes obsolescent.

The difference between a jack of all stats and a lightning bruiser is how it stacks up compared to the competition. There's also the question of whether a design was a bad idea in the first place or a great idea deployed poorly. A cruiser was supposed to be able to operate independently at long range, kill what it can catch, outrun anything that could hurt it. So it really has no business being in the line of battle against battleships. And battle-cruisers with battleship-level guns get spanked hard.

That's actually a parallel to the lesson the Japanese learned with their fighters. Faster, more maneuverable than the American models but ours had armor and self-sealing fuel tanks. The penalty we paid for that was worth it.

Interestingly enough, the M1 Abrams was supposed to have trouble defeating its own armor with the main gun. Some advanced Soviet designs with explosive-reactive armor were highly resistant to contemporary NATO anti-tank rounds.

There are a couple points left off the triangle. In addition to attack, defense, and speed, you have maintenance expense/reliability, manufacturing expense, range and difficulty of operation. A wonder-weapon does no good if there aren't enough to go around, they're always breaking down, and they tend to kill the crews by being ornery.

Sometimes a design gambit works. We love talking about lancers but that's pretty much fitting the trope of a hard-punching, thin-skinned, expendable weapons system. If you strike the design balance right versus your opponents, you've got a real force multiplier. You get the balance wrong and you're pretty much inviting defeat in detail as your dreadgnats are picked apart.

The story of the Sherman tank is along these lines. They knew there were weaknesses in the design but figured that it would be better to run with what they had (which they thought was adequate) versus taking longer to retool for a better design and churn out an army's worth of tanks. The Israelis made modifications to the design that really improved it.

Byron said...

Milo:
I'm not sure why you need a drone for this though. If your goal is to dazzle sensors, rather than confuse them with decoys, then you could just as well accomplish that with lasers onboard your capital ship.
The only reason I can think of to use a drone is for blinding kinetics that have a home-on-jam capability.

FBH:
You're straying too far into naval practices. There's no horizon in space, and point defense is likely to be substantially easier.

FBH said...

Bryon:

I know. I was talking specifically about naval vessels.

That said in high visibility space the same "optimal" size is likely to apply.

Byron said...

FBH:
I know. I'm just a little paranoid about naval anologies after several have been blown totally out of proportion.

On lighting bruisers, the best example I can think of is the Iowa-class.
They were fast, well-armored, and well-armed. They were also expensive, and weighed 10,000 tons more then the South Dakotas, and the only improvement was 6 knots in speed. See here for an interesting comparison of battleships of World War II.

Tony said...

Byron:

"Exactly. This is a rebuttal how? There are advantages to naval air power that outweigh the drawbacks. The same isn't necessarily true in space."

I wasn't making a rebuttal. Your assertion doesn't need one. It's a fact, but it isn't a particularly relevant one. A battleship is just as much a single point of failure, WRT to the firepower that it individually carries, as a carrier is. It's a red herring argument to say that a carier is a more especially single point of failure.

"Orbital fighters were mentioned at the end of the section."

Yes they were, at the end of a long string of straw man arguments designed to discredit the parasite concept as much as possible in the eyes of the reader. I saw what you did there.

"I did deep space first because it's an easier environment to analyze."

You mean easier to set up and tear down straw men. I get it.

"However, you're still ignoring the critical fact. The fighter can't win against the big ship. PT boats were better close to the coast then bigger ships were. Does that mean there were PT boat carriers? Not after the first time it was tried. Similarly, why is the parasite superior in battle to a bigger ship? It can move faster, but I submit Standard Type logic here. How fast you are doesn't really matter. Threaten something important and force your enemy to give battle."

What big ship is this? I don't see a rational requirement for one in orbital combat. Once again, you're presuming a deep space combat environment that simply isn't realistic. Then you erect straw men designed to make the battleship seem the only obvious solution.

"Not this again. Give me one concrete example of this situation."

Carrier/mothership/whatever in very high altitude orbit, say 2 light seconds above the planet. (Such orbit being adopted because it is relatively hard to attain from a planet's low orbit, and gives plenty of time to detect and react to threats originating there.) Parasites making attack run against targets in orbit or on the ground on opposite side of planet (at time of attack). Or perhaps the parasites are in low orbit on patrol, and are attacked while behind the planet from the POV of the carrier. This leaves at least a four second round trip communitcation lag, plus the requirement to emplace at least one comm relay that is vulnerable to enemy countermeasures. Can't get more concrete or realistic than that.

"Also, the presumption of no deep-space combat seems hasty. It would make sense to launch missiles at the carrier as early as possible. It wouldn't be fleet-to-fleet, but it would be there."

Just another threat to take into consideration. I don't see how parasites would necessarily be involved. Even if you launched them to free up their firepower for defense, they wouldn't be burning up a bunch of delta-v going to and fro, just hanging out in the neighborhood of the carrier.

Byron said...

Yes they were, at the end of a long string of straw man arguments designed to discredit the parasite concept as much as possible in the eyes of the reader. I saw what you did there.
Obviously I'm somehow biased against space fighters, and ignoring solid arguments involved for nefarious reasons of my own. Remind me again what those arguments are?


Carrier/mothership/whatever in very high altitude orbit, say 2 light seconds above the planet. (Such orbit being adopted because it is relatively hard to attain from a planet's low orbit, and gives plenty of time to detect and react to threats originating there.) Parasites making attack run against targets in orbit or on the ground on opposite side of planet (at time of attack). Or perhaps the parasites are in low orbit on patrol, and are attacked while behind the planet from the POV of the carrier. This leaves at least a four second round trip communitcation lag, plus the requirement to emplace at least one comm relay that is vulnerable to enemy countermeasures. Can't get more concrete or realistic than that.

There two main problems with this. First, why so far out? 2 light-seconds is past lunar orbit, and well outside any weapons range I expect to see. Maybe you would place surveillance satellites out that far, but not the mothership. Second, you completely missed the point of the question. Give a concrete example of a situation in which it matters. When will 6 seconds of reaction time be sufficient, but 8 or 10 not be? I can't think of any situation where this is the case that's likely enough to make this practical.

What big ship is this? I don't see a rational requirement for one in orbital combat. Once again, you're presuming a deep space combat environment that simply isn't realistic. Then you erect straw men designed to make the battleship seem the only obvious solution.
This is the big ship that travels through deep space, then fights in orbit. And it has a longer range because of how lasers work. If you claim that big ships are unrealistic, then fighters are the only answer. You have yet to give any reasons for the superiority of fighters in combat with those big ships. Maneuverability is the only thing you've said, and you haven't even explained how that applies.

Just another threat to take into consideration. I don't see how parasites would necessarily be involved. Even if you launched them to free up their firepower for defense, they wouldn't be burning up a bunch of delta-v going to and fro, just hanging out in the neighborhood of the carrier.
The problem is that the carrier-parasite combination is more expensive than the battleship one, and less capable of defending itself against these sorts of missile attacks. Also, it has not been shown to be of notably more utility in combat.

jollyreaper said...

On lighting bruisers, the best example I can think of is the Iowa-class.
They were fast, well-armored, and well-armed. They were also expensive, and weighed 10,000 tons more then the South Dakotas, and the only improvement was 6 knots in speed


They're on the Tropes list. :) It's funny how fast-battleships managed to take the battle-cruiser's hat.

One of the ideas I had for generic space warships is taking the mighty glacier idea further. These are ships that barely eke it out with strategic-level mobility. They're not meant to chase down enemy fleets but threaten fixed targets. They're big enough that the only solid counter against a line of them is another line of glaciers. The attacker will move against an enemy's valuable static target (planet, asteroid mines, etc) and so the defender's fleet is either forced into battle or give up the target without a fight.

The mighty glaciers would be the biggest and baddest warships in space, capable of dishing and taking damage that's at the maximum scale.

What are their drawbacks?
1) Expensive to build, maintain.
2) Specialized, only good at all-out fights, not general-purpose.
3) Slow. Brings the fight with it but the enemy has to agree to play.
4) Tremendous concentration of resources, one of them vs. a dozen general purpose independent-operation cruisers.
5) You only have so many of them.

If you could put a line of these at every strategic target in the theater, the enemy is boned. But you can't so here's where you run with trade-offs. How many can you afford to build, where do you need to cover, which needs can be met by smaller ships, etc?

Note that the descriptions are generic at this point. Not talking imaginary weapons, propulsion, armor, etc, just generalities.

I like the tropes writeup on the dreadnought.

Ship of the Line/Battleship/Dreadnought - A massive ship, usually the largest ship in the fleet, bristling with big guns. The navy's Mighty Glacier. (Note that the term "fast battleship" exists, because some of them, like the Iowa, were really fast in addition to having shitloads of guns and armor. In the real world, being huge meant that they had more room for sailes/engines/reactors, meaning that Bigger Is Better in almost every respect. However in sci-fi, they practically always move at a snail's pace because really heavily armed and armored AND really fast ships would leave those taking Artistic License with Economics the question 'Why do we make anything else ?' For the rest of us, the answer is logistics and economics. Even strategy games, which often abstract or handwave away advanced economic concerns, recognise that bigger ships take more resource and time to build while requiring more crew or advanced AI control. Depending on the faction's economic capabilities, it's simply not possible to build only capitals.)

Tony said...

Byron:

"Obviously I'm somehow biased against space fighters, and ignoring solid arguments involved for nefarious reasons of my own. Remind me again what those arguments are?"

I'm just reporting what I see. Deep space combat isn't even a good idea with magitech torch drives. It involves too much risk of leaving the defended locality undefended at the wrong time. So anything that invokes deep space combat strikes me as either misguided or rhetorically instrumental. Pick one, or give me a third alternative -- one consistent with the principles of war and realistic physics.

"There two main problems with this. First, why so far out? 2 light-seconds is past lunar orbit, and well outside any weapons range I expect to see."

Sounds to me like a good reason, not a problem. Remember, if you have a carrier with you, it's because you are attacking, and need a carrier -- certainly to get there, and possibly to get home. If you are defending, no reason to have one, in any orbit.

"Second, you completely missed the point of the question. Give a concrete example of a situation in which it matters. When will 6 seconds of reaction time be sufficient, but 8 or 10 not be? I can't think of any situation where this is the case that's likely enough to make this practical."

I gave you a situation. You simply chose to ignore it: comm relays are vulnerable -- so vulnerable there's no imaginable reason that the enemy would ignore them. If your tactical system relies on human decisionmaking, you have to have a human within line-of-sight of the decision point. Might as well put him at the decision point in that case.

"This is the big ship that travels through deep space, then fights in orbit."

Why? The defenders won't have big ships if all you need a big ship for is to travel some distance. They'll have smaller, more maneuverable ships for orbital work.

"And it has a longer range because of how lasers work."

Remember, there's no realistic reason to buy-in to the laserstar future. In fact, there are real-world engineering constraints that suggest that lasers will be relatively short ranged weapon systems. Invoking long range lasers as if they were a foregone conclusion is not valid.

"If you claim that big ships are unrealistic, then fighters are the only answer. You have yet to give any reasons for the superiority of fighters in combat with those big ships. Maneuverability is the only thing you've said, and you haven't even explained how that applies."

Jeepers. Yes I have explained why maneuverability is important. If you're in an orbit and want to change its altitude or inclination under combat conditions, you want to do it as near to instantaneously as possible, not wait weeks for a micro or milligee drive to do it. That requires relatively inefficient high-impulse propulsion technology. If one has to use such technology, does one want to apply it to just the weapons and a short endurance cockpit, or to an entire interplanetary hab, interplanetary drive, interplanetary fuel supply, interplanetary etc?

"The problem is that the carrier-parasite combination is more expensive than the battleship one, and less capable of defending itself against these sorts of missile attacks. Also, it has not been shown to be of notably more utility in combat."

Why is the carrier more expensive? They certainly weren't historically, until the era of the supercarrier. Rationally, the carrier is a hab, an interplanetary drive and fuel/remass, and maybe some defensive systems. Include the cost of the parasites and you maybe cost yourself more than a battleship. But the battleship is nonexistent to begin with, and the parasites deliver more flexibility.

WRT utility in combat, the carrier isn't going to be in combat. The parasite group will, probably at several different places at once. A battleship can't do that.

Rick said...

Welcome to new commenters, notably including Ken Burnside, who has been a huge influence in the background of this blog.

We have talked here about ravening beams of death (RBoDs) - not quite magitech, but Wagnerian in sheer scale.

My own thinking about laser stars, etc., is predicated on effective, practical laser ranges of a fractional light second, but at least in the thousands of km.

Fit a high power laser installation to a nuke electric drive bus and you have a mobile weapon station that can be dispatched on interplanetary missions. A laserstar.

My ideal sperical cow version is just that, a theoretical case. In practice, a laserstar is inherently big and expensive, and there is a case for adding a hab for maintenance staff over prolonged missions, plus on-station mission control, and supplementary armament of whatever sort, including espatiers.

But there is an interesting practical hitch. In deep, open space a laser star has hours to engage any approaching target(s). But in planetary orbital space they are highly vulnerable to nasty surprises delivered from.

On the other hand, orbital space could have a place for (probably smaller) buses with chemfuel engines. These buses may be pure missiles. But in orbital planetary space there is also a case for armed patrol craft, putting observers on the spot, armed with a few rocket-boosted SCoDs.

They are not an 'efficient' way to deliver kinetics, but an effective way to threaten their use, and fire a salvo if need be.

On the third hand, chemfuel puts a severe clamp on how much your orbital patrol craft / fighters can change orbit before the tanks run low, and it is not very much.

Of course, constellations of laser stars and patrol craft are inherently operatic anyway, so perhaps a little song and dance are justified.

Byron said...

Tony:
I gave you a situation. You simply chose to ignore it: comm relays are vulnerable -- so vulnerable there's no imaginable reason that the enemy would ignore them. If your tactical system relies on human decisionmaking, you have to have a human within line-of-sight of the decision point. Might as well put him at the decision point in that case.
This is stupid. Comm relays are vulnerable. So are satellites today. So? Put up a dozen relays.
My question was this. In what situation could the light-lag prove decisive? You have yet to answer that. My guess is that you don't have an answer. All action will either take place so quickly that human intervention is impossible, or slowly enough that a few seconds of light lag are negligible. We did this once before, and you're repeating the same arguments that you failed to support then.

Jeepers. Yes I have explained why maneuverability is important. If you're in an orbit and want to change its altitude or inclination under combat conditions, you want to do it as near to instantaneously as possible, not wait weeks for a micro or milligee drive to do it. That requires relatively inefficient high-impulse propulsion technology. If one has to use such technology, does one want to apply it to just the weapons and a short endurance cockpit, or to an entire interplanetary hab, interplanetary drive, interplanetary fuel supply, interplanetary etc?
And why is the ability to quickly change orbit important? Stop dodging the question, and give me an example of orbital maneuverability being so important. If you need to hit something now, just use missiles.

Remember, there's no realistic reason to buy-in to the laserstar future. In fact, there are real-world engineering constraints that suggest that lasers will be relatively short ranged weapon systems. Invoking long range lasers as if they were a foregone conclusion is not valid.
Relatively short-ranged compared to what? We're still talking thousands if not tens of thousands of kilometers. At orbital velocities, that's a long time. And a bigger laser is going to beat a group of smaller lasers of equal cost. So unless the maximum practical laser is fighter-sized (special pleading alert) the bigger ship wins the duel. The exact number of weapons mounted is irrelevant.

Why is the carrier more expensive? They certainly weren't historically, until the era of the supercarrier. Rationally, the carrier is a hab, an interplanetary drive and fuel/remass, and maybe some defensive systems. Include the cost of the parasites and you maybe cost yourself more than a battleship. But the battleship is nonexistent to begin with, and the parasites deliver more flexibility.
Did you even read the statement? I explicitly said that the carrier-parasite combination was more expensive. And the flexibility of parasites is overrated. Yes, multiple ships can be in multiple places at once. But they will be there with less firepower then is available to the battleship. Notice that in the end of the fighter section of the paper, I described a patrol carrier, which seems quite close to what you describe.
I suppose I should have seen this coming. Next you're going to reject any sort of pitched battle situation, and claim victory. As usual, you work on a completely different wavelength then the rest of us, and accuse us of being wrong for not sharing your starting assumptions.

Rick:
I can see a use for patrol craft, and they may be pressed into service as fighters in wartime, but that's not what they're designed for. It would be sort of like the Coast Guard. Helpful in wartime, but with a totally different design basis from the Navy.

Tony said...

Byron:

"This is stupid. Comm relays are vulnerable. So are satellites today. So? Put up a dozen relays."

You can only carry so many relays, you know. If your enemy knows you rely on com relays to control your drones, you think they won't be able to identify and engage them? You don't think they'll be able to run you out of them sooner rather than alter.

"My question was this. In what situation could the light-lag prove decisive? You have yet to answer that. My guess is that you don't have an answer. All action will either take place so quickly that human intervention is impossible, or slowly enough that a few seconds of light lag are negligible. We did this once before, and you're repeating the same arguments that you failed to support then."

That's way too bold an assumption for me. You rule out a vast middle including both marginal advantages for having humans on the spot to and definite ones. I can't tell you what those might be, but ruling them out a priori is well, "stupid", to borrow a trun of phrase.

"And why is the ability to quickly change orbit important? Stop dodging the question, and give me an example of orbital maneuverability being so important. If you need to hit something now, just use missiles."

What if you have to change orbital altitude or inclination to put your missiles inside their delta-v capabilities?

More importantly, why is the capability to change orbit unimportant? Once again, you're applying a priori reasoning ex officio yourself.

"Relatively short-ranged compared to what? We're still talking thousands if not tens of thousands of kilometers."

Incorrect. That's what you're talking. I'm nowhere near so sure. Nor should you be. Yo're putting yet more a priori assumptions in play.

"Did you even read the statement? I explicitly said that the carrier-parasite combination was more expensive. And the flexibility of parasites is overrated. Yes, multiple ships can be in multiple places at once. But they will be there with less firepower then is available to the battleship."

Less firepower may be enough for the situation. It's called economy of force. That fact that you totally rule the possibility out -- or perhaps don't even realize theere is such a thing -- throws considerable doubt on your reasoning overall.

"Notice that in the end of the fighter section of the paper, I described a patrol carrier, which seems quite close to what you describe."

Not what I'm talking about. I'm talking about a carrier and parasites being the general conceptual solution to a significan performance sifference between interplanetary and orbital propulsion systems.


"I suppose I should have seen this coming. Next you're going to reject any sort of pitched battle situation, and claim victory."

I'm not interested in victory, just lending some realism and clarity into the discussion.

And for that reason alone I would reject a pitched battle in deep space as an artifical and arbitrary straw man. A bunch of small concurrent battles in orbital space? I find that much, much more plausible.

"As usual, you work on a completely different wavelength then the rest of us, and accuse us of being wrong for not sharing your starting assumptions."

My only starting assumption is that the principles of war, and military and technoligcal history are correct. The principles tell us what seems to be constant in conceptualizing warfare and planning for its successful education. Military and technological history tells us that any presumption of new technologies and environments invalidating the principles of war is a fallacious conceit.

If you can't accept, or seek to cricumvent those realities, then you're simply playin intellectual games in la-la land. I believe the word for that is...stupid.

Tony said...

"e principles tell us what seems to be constant in conceptualizing warfare and planning for its successful education

should read:

"The principles tell us what seems to be constant in conceptualizing warfare and planning for its successful execution."

Though the first is accurate as far as it goes...

Anonymous said...

=Milo=



In other news, bomb-pumped lasers are a silly idea. Raise your hand if you're surprised.

Combine that with these new lenses from a while back, and X-ray lasers and perhaps even gamma ray lasers are looking more and more practical.



Byron:

"However, you're still ignoring the critical fact. The fighter can't win against the big ship."

Tony:

"What big ship is this? I don't see a rational requirement for one in orbital combat."

Perhaps the big ship is there to kill fighters?

If it were effective at that, then obviously that'd be a rational reason to have one.



Rick:

"But there is an interesting practical hitch. In deep, open space a laser star has hours to engage any approaching target(s). But in planetary orbital space they are highly vulnerable to nasty surprises delivered from [below?]."

Long-range superlasers are more effective for defense than attack.

If used for attack, the laserstars will likely form a "first wave", softening up the enemy force on approach, then let other ships mop up survivors and hold the captured orbits during the siege. The laserstars may park in high orbit, above most of the fighting, where they provide a role similar to "air support".


"On the third hand, chemfuel puts a severe clamp on how much your orbital patrol craft / fighters can change orbit before the tanks run low, and it is not very much."

I'm still caught up on the idea if you could make an orbital patrol craft making use of the planet's magnetic field (magsail, magnetic tether, etc.). It doesn't sound too easy - I dunno if you could get sufficient acceleration for fast orbit changes, and a large magsail or tether would be potentially fragile (though not as easy to hit as a solar sail). But if it worked, either near Earth or around Jupiter/Saturn, it would be really cool and solve your delta-vee problems.

Byron said...

Tony:
You can only carry so many relays, you know. If your enemy knows you rely on com relays to control your drones, you think they won't be able to identify and engage them? You don't think they'll be able to run you out of them sooner rather than alter.
As usual, you turn a minor problem into an enormous vulnerability. What is the mass of a relay? 1000 kg? If that? So for shaving a person out of a cockpit, I can carry one relay. That same person doesn't have to come at all, so it's more like 6 relays. Now consider shooting down something a light-second out that is that size. The projectile will have to spend hours if not days in transit, and the entire system will probably cost as much as the relay. I'm not going to lose much sleep over it. If it really is that dangerous, I mount some defenses on it. That doubles the mass, and increases the difficulty of a kill by a factor of three or four. I'm not sure what the problem is.

That's way too bold an assumption for me. You rule out a vast middle including both marginal advantages for having humans on the spot to and definite ones. I can't tell you what those might be, but ruling them out a priori is well, "stupid", to borrow a trun of phrase.
The middle can't be so vast if neither of us (and I have been trying) can find a concrete advantage there. Most human-in-the-loop involves classification and decision-making. Given that we're in space, there is no possibility of a surprise meeting engagement. Either one or both sides will know of the other before they meet. If both sides know, the decisions can be made long beforehand, and implemented by the computer. If only one side knows, the other walks into an ambush. Reaction to the ambush will be handled by the computer. The humans are only a very marginal advantage, and that advantage is outweighed by the mass and cost of humans, not to mention the letters that have to be written if the ambush is successful.

What if you have to change orbital altitude or inclination to put your missiles inside their delta-v capabilities?

More importantly, why is the capability to change orbit unimportant? Once again, you're applying a priori reasoning ex officio yourself.

If the missiles are that limited, I don't see your fighter being much better. Or maybe the fact that money is not being spent on fighters allows another stage on the missile.
I simply don't see large orbital maneuverability being important during a fleet battle. That is obviously not the case if it's more of a police action.

Incorrect. That's what you're talking. I'm nowhere near so sure. Nor should you be. Yo're putting yet more a priori assumptions in play.
Most people here share my assumptions. The fact that you don't does not invalidate them, nor are you challenging my process to my conclusions.

Less firepower may be enough for the situation. It's called economy of force. That fact that you totally rule the possibility out -- or perhaps don't even realize theere is such a thing -- throws considerable doubt on your reasoning overall.
I do understand economy of force. However, I don't see the ability of the fighters to be divided up as a major advantage in a battle situation. For patrol duties, sure. Battle, not so much.

Not what I'm talking about. I'm talking about a carrier and parasites being the general conceptual solution to a significan performance sifference between interplanetary and orbital propulsion systems.
This assumes that there is a significant advantage to the orbital propulsion system. Which you have yet to show to be the case.

Byron said...

Tony, cont.:

And for that reason alone I would reject a pitched battle in deep space as an artifical and arbitrary straw man. A bunch of small concurrent battles in orbital space? I find that much, much more plausible.
At the very lowest tech level, yes. You seem to be incapable of realizing that the rest of us do not always work there. That is your problem, not mine.

I am not even going to seek to challenge your attempts to rationalize your position as being the one true view. I've gone there before, but you refuse to even accept the possibility that you are wrong, rendering the debate pointless.

Tony said...

Byron:

"I am not even going to seek to challenge your attempts to rationalize your position as being the one true view. I've gone there before, but you refuse to even accept the possibility that you are wrong, rendering the debate pointless."

Funny thing is, the laserstar future with magitech torch drives comes across to me (and I'm sure not only me) as a "one true view", based on very narrow technical assumptions, skewed towards maximalism and gigantism. What I see happening is you, in defense of such a grand vision, trying to force me to prove a negative. I can't tell you what the advantage of any given capability might or might not be, given unknown technoligcla constraints. The point I am making is that you have adopted a narrow, largely straw point of view, then demanded that any doubts be phrased and discussed within the constraints of that POV.

IOW, I am not interested in whether or not I am wrong in any particular detail. I'm sure that I probably am. I'm just totally unconvinced of the rightness of your POV, and place before the reader the reasons why.

Byron said...

Funny thing is, the laserstar future with magitech torch drives comes across to me (and I'm sure not only me) as a "one true view", based on very narrow technical assumptions, skewed towards maximalism and gigantism. What I see happening is you, in defense of such a grand vision, trying to force me to prove a negative. I can't tell you what the advantage of any given capability might or might not be, given unknown technoligcla constraints. The point I am making is that you have adopted a narrow, largely straw point of view, then demanded that any doubts be phrased and discussed within the constraints of that POV.

IOW, I am not interested in whether or not I am wrong in any particular detail. I'm sure that I probably am. I'm just totally unconvinced of the rightness of your POV, and place before the reader the reasons why.

Really? This is the reason behind "all warfare is the same"? My POV is based on an attempt to work from as close to first principles as possible. This includes things like laserstars (which are based on the principle that a big laser is better then two small ones). Also, where did torch drives come from? Or is this the "we won't have enough presence for space war unless we have torch drive" again?

The comment you quoted was addressed at the assertion that all warfare is the same, btw. I still think that at the level we work at this is not true. Attempts to apply it remind me of Holland Smiths comments about admirals trying to be generals.

Tony said...

Tony:

"Really? This is the reason behind 'all warfare is the same'?"

It's not the reason for anything. It's a simple fact -- I'm not convinced.

"My POV is based on an attempt to work from as close to first principles as possible. This includes things like laserstars (which are based on the principle that a big laser is better then two small ones)."

How do laserstars emerge form first principles? They rely on some pretty narrow assumptions -- lasers accurate enough to hit small targets at fractional light second ranges. At the same time, these lasers are completely invulnerable to alternate means of attack. It also assumes an economy capable of building such stupendous machines at a practical cost. That's a long, long way from first principles.

"Also, where did torch drives come from??"

Your words:

"At the very lowest tech level, yes. You seem to be incapable of realizing that the rest of us do not always work there."

Since I'm thinking of anything up to nuclear thermal for tactical propulsion and low thrust fusion for strategic propulsion, I think the next step up the ladder would have to be at least demi-torch in nature.

"Or is this the 'we won't have enough presence for space war unless we have torch drive' again

Uhhh...you think we will have warfare in space with nothing to fight over?

"The comment you quoted was addressed at the assertion that all warfare is the same, btw. I still think that at the level we work at this is not true. Attempts to apply it remind me of Holland Smiths comments about admirals trying to be generals."

You forget that I am a former Marine with considerable at-sea deployment time. I'm not exactly unaware of differences in implementation details. I'm also aware that Smith was something of a blowhard and inveterate USMC cheerleader. He's not exactly the source you want to quote to me on this point.

In any case, I've never, ever maintained that all warfare is the same. All I've ever said is that the principles of war apply at all times and all levels. Whenever you think you've found a way to circumvent them -- and total firepower dominance is one of the most common examples of that, whether you're talking about nuclear weapons or machine guns -- experience says you're wrong. Laserstars are no exception.

Eth said...

So, it seems that we may have soon antimatter-triggered weapons.
http://atomicrockets.posterous.com/antimatter-weapons

But one of the applications the article describes is "fuel for ultra-fast anti-missile rockets".
Does someone know what would be the performances of such a rocket?

Byron said...

Tony:
How do laserstars emerge form first principles? They rely on some pretty narrow assumptions -- lasers accurate enough to hit small targets at fractional light second ranges. At the same time, these lasers are completely invulnerable to alternate means of attack. It also assumes an economy capable of building such stupendous machines at a practical cost. That's a long, long way from first principles.
Let's see...
First, I don't see being able to hit at tens of thousands of kilometers (.3 ls or less) as being too outrageous. It's probably not guaranteed, and damage at long range might not be great, but I see no reason it's impossible.
Second, the definition of a laserstar is a vessel designed to mount the largest feasible laser. That could well mean a moderately-sized vessel, which you have a lot of. Something more akin to a modern cruiser/destroyer. A fleet might include a dozen or more, instead of the one or two you've been assuming.
Third, what alternate means of attack? Kinetics? The primary offensive weapon is also the primary defensive weapon, and can hit kinetics farther away then a smaller craft can.
Fourthly, there is no reason that secondary weapons can't be mounted. It's just that there is no pressing reason to mount multiple primary weapons unless there are some very strong economies of scale in ships while there are equally strong diseconomies in laser mirrors.


In any case, I've never, ever maintained that all warfare is the same. All I've ever said is that the principles of war apply at all times and all levels. Whenever you think you've found a way to circumvent them -- and total firepower dominance is one of the most common examples of that, whether you're talking about nuclear weapons or machine guns -- experience says you're wrong. Laserstars are no exception.

What you generally do is wave some principle around to disprove something. Take the above mention of economy of force. It makes sense, but by your reasoning, forces should be subdivided into the smallest possible units to allow for maximum economy of force. Why don't we just assign men to task forces for each battle? It allows us to precisely tailor forces to achieve maximum economy of force.
The above is ridiculous, but follows your reasoning quite closely. It's entirely possible that multiple laserstars will substitute for one carrier, for example. Or that, I don't know, there could be smaller laserstars made for those sort of jobs.

Eth:
I'm highly skeptical of any claims for military use of antimatter. The stuff is dangerous and expensive, and the storage requires active power. This is not something the military likes.

Tony said...

Byron:

"Let's see...
First, I don't see being able to hit at tens of thousands of kilometers (.3 ls or less) as being too outrageous. It's probably not guaranteed, and damage at long range might not be great, but I see no reason it's impossible."


Of course it isn't impossible -- we already shoot lasers at the Moon and get a return from a reflector less than a meter on a side. But note that we do this by "reversing the polarity" of telescopes on solid ground bases, and getting a return can take some pretty fine tuning over several minutes.

But, move the setup into space, introduce the jitters of a working spaceship in combat conditions, and try to add orders of magnitude more energy to the process. Here one starts running into the difference between "technically possible under controlled conditions" and "practical for military application".

"Second, the definition of a laserstar is a vessel designed to mount the largest feasible laser. That could well mean a moderately-sized vessel, which you have a lot of. Something more akin to a modern cruiser/destroyer. A fleet might include a dozen or more, instead of the one or two you've been assuming."

Come now...we've been hearing for years about laser generators hundreds or thousands of meters long, with gigawatt or even terawatt levels of steady power supply. Either we take those estimates at face value, or we admit that "laserstar" means whatever is conveninient for one at the moment.

"Third, what alternate means of attack? Kinetics? The primary offensive weapon is also the primary defensive weapon, and can hit kinetics farther away then a smaller craft can."

Lasers aren't useful for much, B. Even battleship guns could fire HE. So setting the up as the primary weapons is disingenuous from the start. Resources will have to be expended on kinetics and explosives non anti-ship missions. That limits the number and size of lasers, and thus their effectiveness.

Aside from that, you're presuming perfect sensors in a perfect sensor environment. Given all the junk flying around at interplanetary velocities that hits the Earth every day, there is no other word than preposterous. I doubt kinetic weapons would be discernable at very long ranges at all, given how much junk the sensor systems would be dealing with. It's not like they would have to be on an intercept course until the terminal phase of the engagement. Why do we always ignore these things, hmmm?

"Fourthly, there is no reason that secondary weapons can't be mounted. It's just that there is no pressing reason to mount multiple primary weapons unless there are some very strong economies of scale in ships while there are equally strong diseconomies in laser mirrors."

Secondary weapons rob mass and energy from your stupendo photon hose gun, making it less effective.

Tony said...

Byron:

"What you generally do is wave some principle around to disprove something. Take the above mention of economy of force. It makes sense, but by your reasoning, forces should be subdivided into the smallest possible units to allow for maximum economy of force. Why don't we just assign men to task forces for each battle? It allows us to precisely tailor forces to achieve maximum economy of force."

Nonsense -- and argumentum ad absurdum. I only invoke the principles of war when they are being ignored by somebody else. In this specific case, you claimed that some subgroups of parasites could not match the firepower of a battleship. True, but so what? If the firepower they have is adequate for the mission, other parasites from the same carrier groups can be off somewhere else, accomplishing another mission or missions. Tactical flexibility is generally considered an advantage, not a handicap, you know.

"The above is ridiculous, but follows your reasoning quite closely. It's entirely possible that multiple laserstars will substitute for one carrier, for example. Or that, I don't know, there could be smaller laserstars made for those sort of jobs."

Let me get this straight... Multiple giga or terawatt laser generators, with their power supplies and other support systems (and, if mobile, propulsion systems) are going to be more economicalthan a single interplanetary drive bus, a hab, and a group of relatively simple orbital ships? WTF, over?

Also, what's this "smaller laserstars" business. I thought the whole point of laserstars was to eliminate consideration of "smaller" as a bad deal all the way around.

Anonymous said...

If you were to really have light second range lasers - there wouldn't be any orbital conflict ..

At least not orbital conflict where the attackers came from some other interplanetary location.

The Laser Stars would zap any carrier/parasite combo before they came close enough to deploy.

So the parasites or the carrier would have to match the Laserstar for overall effectiveness at range. (KKV cloud, other lasers, w/e)

Depending on whatever closing conditions applied (how fast the laser kills/cycles, relative capabilities, closing speeds, etc)

But if the laser range is very short, Obital conflicts seem fairly likely.

So what is the Laser Range? Mass? Power? Effective Duty Cycle?

I am still going with undefined.

(SA Phil)

Byron said...

Tony:
But, move the setup into space, introduce the jitters of a working spaceship in combat conditions, and try to add orders of magnitude more energy to the process. Here one starts running into the difference between "technically possible under controlled conditions" and "practical for military application".
We obviously don't agree on where that line is. I'm done here.

Come now...we've been hearing for years about laser generators hundreds or thousands of meters long, with gigawatt or even terawatt levels of steady power supply. Either we take those estimates at face value, or we admit that "laserstar" means whatever is conveninient for one at the moment.
I've always been a bit skeptical of the hundreds of gigawatts claims myself. The point of the concept is that if one chooses to use the laser as the primary offensive weapon, there is no reason to have more then one.
As an example of cost, I'll use numbers from my spreadsheet, which contains the best PMF numbers I can come up with. A 100 MJ pulsed laser generator which fires every 10 seconds is $800 million and 144 tons. The accompanying mirror is about 20 meters, and 20 tons, and costs about 800 million. None of these seem terribly out of line for a major warship today, much less in the future. CVN-78 is supposed to be about 13 billion.

Lasers aren't useful for much, B. Even battleship guns could fire HE. So setting the up as the primary weapons is disingenuous from the start. Resources will have to be expended on kinetics and explosives non anti-ship missions. That limits the number and size of lasers, and thus their effectiveness.
What do you mean, not useful for much? It will destroy things. That's the point of a weapon.

Aside from that, you're presuming perfect sensors in a perfect sensor environment. Given all the junk flying around at interplanetary velocities that hits the Earth every day, there is no other word than preposterous. I doubt kinetic weapons would be discernable at very long ranges at all, given how much junk the sensor systems would be dealing with.
Because there is lots of junk that happens to be passing within the threat envelope of the vessel at high velocity, and of the appropriate size. According to NASA, there are about 21,000 pieces of debris larger then 10 cm in orbit. How often is one of those pieces likely to come within the threat envelope of the vessel in question? Once an hour, if that? Burn it and be done.

Let me get this straight... Multiple giga or terawatt laser generators, with their power supplies and other support systems (and, if mobile, propulsion systems) are going to be more economicalthan a single interplanetary drive bus, a hab, and a group of relatively simple orbital ships? WTF, over?
Depends on the size of the carrier, doesn't it. If the lasers are limited to the $250 million range (which gives me 30 MJ every 10 seconds and 11.5 meter mirrors) then a carrier and parasites could well be more expensive. From the same sheet, a 100 MW thrust power electric drive and reactor is about $600 million. Remember those vaunted economies of scale from Space Warfare XIII? How do those affect the fighters?

Also, what's this "smaller laserstars" business. I thought the whole point of laserstars was to eliminate consideration of "smaller" as a bad deal all the way around.
I mean that it might be theoretically possible to build a one primary laser vessel that is smaller then the maximum practical. Even though the scaling laws are against it, it's better then, say, a group of fighters of equal cost.

Thucydides said...

A few general points here:

1. Decoys and obscuration will not be very effective at any range, since any halfway competent force will be employing multiple sensors. In a space environment they will also be in widely separated multiple orbits so you can essentially create a 3D picture of the oncoming force (or defending force for that matter). At tactical distances, you may have to rely on computer memory and some extrapolation to find enemy ships as sensor platforms get zapped and updates from distant platforms come in a second or two out of date, but right up until the opening shots you will have a very detailed picture of what is going on.

2. Laser weapons can have considerable utility at "scorch" ranges by overwhelming sensors, interfering with heat rejection, painting targets for KKV's and so on, even before the laser platform reaches kill range (whatever that might be). Since high power lasers have already been demonstrated tracking and hitting targets from aircraft in flight and warships at sea, the engineering problems of scale, isolating vibrations and target tracking can be taken as solvable. A laser armed spaceship in orbit will actually be contending with fewer environmental issues than one on an in flight 747 or destroyer at sea.

3. The idea that you can hide in LEO from a long range sensor only works half the time; your orbit will take you in range of sensors (and possibly weapons) the other half of the time. Even parking you platform in GEO gives you a huge advantage over forces in LEO or attempting to launch from the ground. In general, being in higher orbit trumps being in lower orbit, and you will want to have some sort of system that can strike targets from that range if at all possible.

4. Magsails are an interesting special case, and I can see them being used as a sort of cruise engine or to perform plane changes out of contact, but once action is joined, then a higher thrust option makes more sense. Economizing on reaction mass when out of contact is a very useful attribute.

5. Demi operatic drives have been described in current technical literature, ranging from ORION pulse drives (and various ideas which borrow from the pulse drive principle) to "dusty plasma" fission fragment reactors, with thrust measured in tens to hundreds of pounds and exhaust velocities of @ 1% c. Most of these are buildable with current technology, and some have even been done in "proof of concept" versions. If people want to go to war over something in space, it isn't like we have a limited number of options.

Anonymous said...

Byron,

I've always been a bit skeptical of the hundreds of gigawatts claims myself. The point of the concept is that if one chooses to use the laser as the primary offensive weapon, there is no reason to have more then one.
As an example of cost, I'll use numbers from my spreadsheet, which contains the best PMF numbers I can come up with. A 100 MJ pulsed laser generator which fires every 10 seconds is $800 million and 144 tons. The accompanying mirror is about 20 meters, and 20 tons, and costs about 800 million. None of these seem terribly out of line for a major warship today, much less in the future. CVN-78 is supposed to be about 13 billion.

--------------------------

I found your spreadsheet interesting before and it still is interesting - but where do these cost and mass numbers come from?

Other than the 20 meter mirror and how it would effect laser diffusion/optics - isn't it speculation?

A quick goggle search seems to indicate 2 MJ lasers are record setters.

Maybe I am mistaken and the 100 MJ is a real project. In which case I apologize in advance for my incredulity.


===========
Below is a link for a 3.5 Billion dollar research facility which includes what at the time was called "the world's biggest laser" which is called 1.8 MJ.

http://www.technologyreview.com/news/412723/the-worlds-biggest-laser-powers-up/
================



(SA Phil)

Rick said...

I thought the whole point of laserstars was to eliminate consideration of "smaller" as a bad deal all the way around.

The point of the spherical cow version is simply to be a starting point for thinking about the military use of big lasers. Not to be the final word on the subject.

If long-range laser weapons turn out to be non-viable, discussing their characteristics is moot. But my gut feeling is that laying down an effective zap to several thousand km will turn out to be practical.

And if you have nuke (or solar) electric power plants capable of pushing transport-class spacecraft at a milligee, you have multimegawatts of sustained power to call on, and radiator capacity to shed the waste heat


Long-range superlasers are more effective for defense than attack.

Yes. I first considered them as 'monitors' to defend some region of local space - such as a planet's orbital space - from hostile intruders coming in from deep space.

But as often happens, tactical defensive can become strategic offensive, if you send laser stars out to control deep-space approach to a planet or region of space.

Given all the junk flying around at interplanetary velocities that hits the Earth every day, there is no other word than preposterous.

There is no military-level effort, today, to detect that stuff. A major ship or constellation will have a robust scan suite.

And to modify a contemporary naval aphorism, don't scan for the arrows, scan for the archers. Once you are tracking the archers it will be a lot easier to detect any arrows they shoot.

Rick said...

As an aside, Brett asks: Does the Midsize Insider have its own separate feed for your stuff there?

Alas, apparently they don't; you have to go to the site. I have a link at the top of my links roll.

Anonymous said...

I don't think powering the "main" weapon will be a problem.

Whether it is a rail-gun, coil-gun or laser.

You can just line the weapon with super-capacitors which you charge from a fission reactor.

Even if that is the only reason you have the reactor - if this is the main weapon, putting the power source seems like an obvious idea.

Battleships carried shells, Ships of the line carried powder and canon balls, etc.

If a Defense oriented Laser Star is in an Orbit near Earth (or a surrogate), It could even use solar power.

How long the laser has to charge up between shots would be part of the feasibility calculations of killing it with KKVs.

(SA Phil)

Anonymous said...

The obvious suggestion comes to mind - if Nasa knows there ~21,000 pieces 10cm or larger in orbit - it implies that there is a way to track them.

The incoming missile bus will be under power -- you could watch that to know where the Soda Cans of Death will likely emerge.

You could paint that area with LIDAR/direction radar.

(SA Phil)

Anonymous said...

Byron, Tony:
You both seem to push each other to the extreme, opposite ends of the military spectrum; I can see uses for Laserstars, as well as aerospacefighter carriers;Byron, you can let your ships plow through the clouds of shrapnal that orbital combat will produce, but I'd like to avoid it...Tony, I'm pretty sure that there will be military utility for high powered lasers; perhaps for thermal killing survillance sattilites. I still think that space combat will not be domminated by any one type of ship, or weapon, but each battle will be matched with whatever ships/weapons would be the best for that situation; any 'one-size-fits-all' type doctrine generally leads to defeat.

Ferrell

Byron said...

Phil:
I found your spreadsheet interesting before and it still is interesting - but where do these cost and mass numbers come from?
They're sort of made up. I looked around for whatever numbers I could find, plugged them in, then played with them until I had something that seemed reasonable. The genesis of the project was in a wargame, so there were elements of game balance. I view it as a reasonable baseline PMF.

I think you might be confusing joules and watts. Yes, the laser described is significantly more powerful then anything we have today. However, it's a top-of-the-line system, or something close to it.

Ferrel:
You seem to be the only person discussing aerospace fighters, particularly from a carrier. Carried aerospace fighters would be air fighters deployed from space, not terribly useful in space.
Claiming that one-size-fits-all leads to defeat is all very well, but it underscores the need to look closely at the optimum force.

Sabersonic said...

Might as well add in my two cents on the subject while I can before the green vs. purple argument erupts again.

I can only assume that, in the PMF scenario that keeps on popping up now and then, the type of orbital warcraft design would mostly be slaved to the maximum possible DeltaV for the engine drive and fuel tanks. Habitat/Drone CPU, armor, active defense systems like CIWS, and even the primary offensive armament will only be as large as the DeltaV (and by extension, the travel time) would allow.

If one could engineer a laser that can strike targets beyond tens of kilometers, then that's great 'till someone realizes that the available engine drive of the time simply can't accelerate that mass beyond mili-gees and let's not get into the possible DeltaV reduction. Add in the highly probable chance that the design in question isn't too turret friendly and what one has is a very expensive, very powerful yet very slow moving target with maneuverability that'll almost make a pregnant hippo seem agile in comparison.

On the other end of the spectrum (and trust me, it pains me to argue against them), the Parasite/Lancer concepts has its own limitations on DeltaV but in a smaller package. So what if one can swarm a larger target, it's not going to do much if it can't do much more than fry the sensors and "scanners". Granted, one can focus primarily on kinetic and missile delivery systems, but then they're finite as well. Once they're exhausted, it's back to square one. And this isn't even going on the subject on the inherent vulnerability the carrier/mothercraft would have, assuming that said military is stupid enough to let said spacecraft be deployed all on its lonesome. Combine Arms is a popular concept for a reason.

And while we're on the subject of Combine Arms, the ideal solution wouldn't really just be focusing on the weapon/deployment concept with the biggest punch and hoping that no-one does a PMF rendition of the Battle of Yavin (star fighters optional) due to a design flaw. Rather it should be units supporting each other where they're weakest so that the other can focus on what they do best, whatever the solution may be.

And speaking of space fighters, a smart sci-fi author could potentially use the DeltaV budget to their advantage to rationalize the Carrier/Parasite craft concept such as one being a mere interplanetary ferry to the orbital-rated Guncrafts that can take said fight to hostile forces. The "Carrier" itself may be little more than the CnC Habitat and some Point Defenses attached to the IP drive if they are so inclined.

As demonstrated numerous times in this forum, I am not so gifted.

And before I go, a highly shameless plug that is semi-relevant to the topic at hand on my own blog site. In short, this little design idea of mine could use a second opinion or three of refinement.

Anonymous said...

Byron,

I think you might be confusing joules and watts. Yes, the laser described is significantly more powerful then anything we have today. However, it's a top-of-the-line system, or something close to it.

=========

No, it is listed in the article as 1.8 MJ anyway.

======================

The National Ignition Facility (NIF), at the U.S. Department of Energy's Lawrence Livermore National Laboratory (LLNL), comprises 192 lasers that fire simultaneously at precisely the same point in space: a sphere of fuel two millimeters in diameter. They are designed to deliver 1.8 megajoules of energy in a few billionths of a second

=====================

Elsewhere it says it is 50 to 100 times larger than any laser that has ever been built.



(SA Phil)

jollyreaper said...


And speaking of space fighters, a smart sci-fi author could potentially use the DeltaV budget to their advantage to rationalize the Carrier/Parasite craft concept such as one being a mere interplanetary ferry to the orbital-rated Guncrafts that can take said fight to hostile forces. The "Carrier" itself may be little more than the CnC Habitat and some Point Defenses attached to the IP drive if they are so inclined.


One way to look at it is your parasites would need the extra living space, fuel tanks, life-support, etc to make that journey and would therefore be individually larger and more expensive. By offloading all of that to a mothership, they can be smaller, faster, and devote their mass budget to weapons and engines. It also makes them tolerably expendable since each dead parasite is far cheaper than an interplanetary-capable dreadgnat.

It seems like a reasonable conjecture but I have no idea how to run the numbers on it. There have been a lot of military ideas over the years that sound reasonable but just don't work in practice.

Byron said...

Sabersonic:
I'm not sure you'd need a turret. The ship should be able to turn just fine.

Phil:
The spreadsheet is a couple hundred years away, and NIF is not a laser weapon. We have megawatt-class weapon lasers today, though they're continuous-beam.

Jollyreaper:
One way to look at it is your parasites would need the extra living space, fuel tanks, life-support, etc to make that journey and would therefore be individually larger and more expensive. By offloading all of that to a mothership, they can be smaller, faster, and devote their mass budget to weapons and engines. It also makes them tolerably expendable since each dead parasite is far cheaper than an interplanetary-capable dreadgnat.
The problem is the duplication of systems between parasite and carrier, not to mention the economies of scale that work against the parasites. I find it likely that the carrier-parasite combination will be more expensive then a battleship of equal weapons budget, which also has more firepower due to laser scaling.

Thucydides said...

A turret seems to be a reasonable part of a laser weapon system, containing the beam expander and focusing mirror (or diffraction grating if you are using an Xaser). The "thimble" on the nose of the Boeing ABL is probably a good mental image, although in a space environment the scale will be quite different. W

ith no aerodynamic considerations to worry about the "thimble" could be quite a bit larger than the remainder of the spacecraft in order to accommodate the largest diameter mirror possible and to ensure vibration dampers and other important parts of the optical train have mounting points. Putting a beach ball on the nose of a scale model 747 might give you the flavour of a fully developed laser turret mounted on a spacecraft.

Byron said...

Thucydides:
The main mirror is likely to be big enough that it is impossible to fully turret. There is also no particular reason to do so. The vessel can turn virtually instantly at the scale of combat. A few degrees for fine adjustments are all that's needed.
The biggest issue with huge turrets is conservation of angular momentum. If the turret is half the mass of the vessel, the vessel will rotate the other way as fast as the turret trains. This cannot possibly be a good thing.

Thucydides said...

The relative mass of the mirror and turret is likely to be a fraction of the mass of the overall spacecraft. One issue with laser armed spacecraft is protecting the mirror. On the ABL, the mirror is rotated "sideways" in relation to the direction of travel, so the Boeing does not plow into a bird or something and damage the mirror. Similar considerations may apply in space with dust, micro meteors and shrapnel (although birds are likely not going to be an issue).

A mirror mounted in such a fashion has a potentially wide field of view, and allows the spacecraft to engage multiple targets such as oncoming clouds of KKV's without having to reorient the spaceship itself.

Since you will need to move the mirror anyway for fine control, a turret mount with a wider range of motion isn't much of an extrapolation. The only thing you won't have is rapidly slewing laser turrets engaging crossing targets; the ships own counter battery missiles or railguns will be trying to shoot those down.

Byron said...


The relative mass of the mirror and turret is likely to be a fraction of the mass of the overall spacecraft. One issue with laser armed spacecraft is protecting the mirror. On the ABL, the mirror is rotated "sideways" in relation to the direction of travel, so the Boeing does not plow into a bird or something and damage the mirror. Similar considerations may apply in space with dust, micro meteors and shrapnel (although birds are likely not going to be an issue).

It's likely to be a significantly larger proportion of the total mass then it is on the ABL.
The problem with "fire to the side" is that the spacecraft's direction of travel is fixed. The ABL can turn broadside quite easily, but the laserstar will have to point the mirror at the target regardless of where that is relative to the direction of travel. And it can turn the entire spacecraft easily enough. Unless it has some form of torch, the engine won't be powerful enough to be tactically effective.
I'm also not sure how effective pointing sideways would be against space debris. Shooting straight ahead is actually the best case for that. The micrometeorites are likely to vaporize in the beam. Pointing just ahead of abeam (relative to the direction of travel) is the worst, as the micrometeorites spend the least time in the beam. However, I'm not sure the hit rate is high enough to be a major concern. Enemy shrapnel is, but that's most likely to come from the same direction that you're shooting.

A mirror mounted in such a fashion has a potentially wide field of view, and allows the spacecraft to engage multiple targets such as oncoming clouds of KKV's without having to reorient the spaceship itself.
The chance of multiple KKVs coming from different angles is quite low. That would either require two enemy fleets or a lot of fancy footwork. Either way, not enough to justify the cost and mass of such a mounting.
My spreadsheet indicates that a turret will be more then twice the mass of a keel mount, and be less accurate to boot. That's not authoritative, but I think it's probably reasonable. The turret just isn't useful enough.

Anonymous said...

Byron said:"It's likely to be a significantly larger proportion of the total mass then it is on the ABL.
The problem with "fire to the side" is that the spacecraft's direction of travel is fixed. The ABL can turn broadside quite easily, but the laserstar will have to point the mirror at the target regardless of where that is relative to the direction of travel. And it can turn the entire spacecraft easily enough. Unless it has some form of torch, the engine won't be powerful enough to be tactically effective.
I'm also not sure how effective pointing sideways would be against space debris. Shooting straight ahead is actually the best case for that. The micrometeorites are likely to vaporize in the beam. Pointing just ahead of abeam (relative to the direction of travel) is the worst, as the micrometeorites spend the least time in the beam. However, I'm not sure the hit rate is high enough to be a major concern. Enemy shrapnel is, but that's most likely to come from the same direction that you're shooting."

First; WTF? I think that you've fundimentally missunderstood what Thucydides was saying; I'm pretty sure he was talking about stowing the laser turret during non-use so as to keep random bits of junk from damaging the lens/mirror.

Byron said:"Ferrel:
You seem to be the only person discussing aerospace fighters, particularly from a carrier. Carried aerospace fighters would be air fighters deployed from space, not terribly useful in space."

You know, since I'm the one talking about them, it would seem reasonable to most people that I would know what it is I'm talking about; Please don't tell me what I mean. An Aerospace fighter is a combat spacecraft that can operate in both orbit and atmoshere; if you don't believe me, ask someone else, they'll tell you. If I had meant a deep space fighter, I would have said that; that I didn't, should tell you that I don't feel that type of spacecraft isn't very likely.

"Claiming that one-size-fits-all leads to defeat is all very well, but it underscores the need to look closely at the optimum force."

Which will be different for different sets of circumstances; state a scenario and we'll be able to come up with battle plans to fit the limitations and goals.

Ferrell

Byron said...

Ferrel:
First; WTF? I think that you've fundimentally missunderstood what Thucydides was saying; I'm pretty sure he was talking about stowing the laser turret during non-use so as to keep random bits of junk from damaging the lens/mirror.
That's what a shutter is for. It doesn't require a turret. Actually, a turret isn't even all that useful in preventing debris damage out of combat. There's a good chance that at least a little bit of stuff would leak through.

You know, since I'm the one talking about them, it would seem reasonable to most people that I would know what it is I'm talking about; Please don't tell me what I mean.
I understand what you mean. What you don't understand is that it isn't a good idea.
An Aerospace fighter is a combat spacecraft that can operate in both orbit and atmoshere; if you don't believe me, ask someone else, they'll tell you. If I had meant a deep space fighter, I would have said that; that I didn't, should tell you that I don't feel that type of spacecraft isn't very likely.
You missed the point. There is no reason whatsoever that a space-based aerospace fighter would fight in space. The penalty of the airframe and engine required to get back to orbit would leave it at a tremendous disadvantage when compared to a dedicated space fighter, to say nothing of a regular warship. Any mass spent on fighting outside the atmosphere is a penalty inside it, and vice versa. Designing for both is going to end up with something that's low-performance, expensive, and difficult to maintain. I'm not sure what else to say.

Which will be different for different sets of circumstances; state a scenario and we'll be able to come up with battle plans to fit the limitations and goals.
To some extent, yes. On the other hand, there are a lot of circumstances when you just need to put a hole in something far away. And the military does have to deal with the problem of not being able to customize a vessel for every task. For a lot of jobs, a laserstar works just fine. It may not be the best possible, but it does a lot of things pretty well.

Anonymous said...

Byron,
The spreadsheet is a couple hundred years away, and NIF is not a laser weapon. We have megawatt-class weapon lasers today, though they're continuous-beam.

----------

We have Gigawatt lasers today. But they seem to be less than 2 Mega-Joules. At least as of 2009.

There was a GW class laser used on tonight's Myth-busters -- which they used to fire at a reflector left by Apollo 15.

Which also had a camera showing the general target area.

Which would indicate that- it is at least semi-feasible to hit a target with a laser at a significant distance.

Of course the laser was likely quite diffuse at that point.

Its not that 100 MJ lasers are probably impossible - its just taking a laser that is much "bigger" than anything we have on Earth. Miniturizing it for use in Space, and deploying it in a Spacecraft seems like a big job.

Not impossible per se - but I bet the early space lasers in that range are going to cost a lot more than the modern equivalent of 800 Million Dollars.

It would also suggest that 100 MJ would probably be a pretty mature Laser Weapon, after the technology has been proven out.

Much like Dreadnaught had 12 inch guns compared to the far more energetic 16 inch canons on the Iowa.

(SA Phil)

Byron said...

Phil:
We have Gigawatt lasers today. But they seem to be less than 2 Mega-Joules. At least as of 2009.

There was a GW class laser used on tonight's Myth-busters -- which they used to fire at a reflector left by Apollo 15.

That was not a Gigawatt-class laser. I saw that episode, and there was no mention of that. The NIF is terawatt-class, but only for very short periods.

You've described the scenario pretty well. It's my guess at a reasonable, mature set of technologies. Definitely not first-generation.

If you want to simulate first-gen stuff, or just try out numbers, almost everything is on the constants page.

Anonymous said...

I agree with Byron on the turret -- why bother?

If you have ranges in the 10,000's of kilometers the vector changes are going to be pretty slow for most of the fight.

The trope is that Sci Fi authors forget that space is three dimensional, and the combats are 2D.

But in reality with a sufficient kill range on a real Laser Star the fight would be nearly One dimensional.

like two locomotives passing in a train tunnel.

The Laser Star needs to kill its attacker before it gets anywhere near close, since a nearby kinetic will ruin it.

I imagine that's where the constellation kicks in. You have a couple of short range Laser/Kinetic based escorts to fight/defend the Laser-Star for the knife fighting portion of the battle. Which due to likely high closing velocities- Would be extremely short.

The attacking force wouldn't slow down as it approached, because that would make all its kinetics far less effective. Because the Laser-Star's effectiveness is a inverse function of closing velocities.

Which would possibly argue against parasite fighters slowing down to fight in the closer orbitals, I suppose.

(SA Phil)

Anonymous said...

Byron,

That was not a Gigawatt-class laser. I saw that episode, and there was no mention of that.

---

Hmmm.

I remember it quite clearly. Jamie made a point to explain it when comparing it to a pen pointer in the milliwatts.

(SA Phil)

Anonymous said...

RE: Mythbuster laser

http://www.youtube.com/watch?v=0dTATMEJSuQ

1 Gigawatt -- At 0:30

the internet is scary sometimes.

(SA Phil)

Byron said...

Oops. I guess I forgot that bit. That's pulsed, and the one I described from the sheet is probably 100 GW or more. Also, firing through a much larger mirror. What they did was made a spot which contained the reflector. There is no way they actually pointed straight at it.

Anonymous said...

I was thinking about this for a bit.

I am not sure all the potentials for faster kinetics has been explored.

You look at coilguns and how they can't really add massive velocity to a projectile unless is is dime thin, and there are big limitations.

You look at railguns and how the fact they would blow themselves apart would cause limitations.

But the distances these PMF spacecraft will be fighting at demands huge closing velocities. Especially as the Lasers gain in power/range. The faster you can push out your missiles/missile buses the better.

One of my favorite hyper-velocity devices is the Light Gas gun. A combustion light gas gun was considered as a competitor for the Rail-Gun which eventually won out in that new Navy Destroyer.

The specifics are the maximum velocity is based on the speed of sound in the light gas being chosen. Hydrogen is the favorite since that speed is 3.8 times that of Air, thus a LGG can theoretically have 3.8 times the velocity of a standard canon.

A standard canon can get a velocity of around mach 5, thus the LGG could potentially do Mach 15.

This speed of sound in the working fluid though goes up with temperature--- leading to designs with arc heating of the hydrogen.

So for a really "big gun" Kenetic launcher -- what if you take that hydrogen near the point it will melt the Gas Gun?

There are already have Nuclear reactors on board, which already are heating a working fluid up to melt stuff on your ship range-- just combine these two features.

A Nuke Thermal Gas Gun.

(SA Phil)

Byron said...

Interesting thought, though not likely. Light gas guns do not seem adaptable to weaponizing. They seem to require a lot of work to reset, which doesn't bode well for a weapon. Nor does the very high acceleration seem like a good thing for guided rounds, and the unknown quantity of hydrogen required might complicate logistics.
The combustion light gas gun is quite different from those used for orbital debris work, giving slightly improved performance over traditional guns. A little bit of research suggests that the gun for the navy is capable of 2.5 km/s. Which is right about what the railgun does.

Anonymous said...

A standard Light Gas gun is a compression wave device, transferring the energy of a conventional nitrocellulose explosive into a faster working fluid. It is only designed for small projectiles.

The Combustion gun is simpler because the "burn" takes place in the same location as the working fluid. But using that method has a limitation. There is oxygen involved, its essentially a rocket gun. The oxygen will lower the combined speed of sound I believe.

Also it is designed for sustained fire - I don't think the gun is designed to operate close to the melting point. And I doubt it is constructed of Superalloy / Tungsten / Carbon, etc.

I think this is probably similar to how rocket propulsion works. Which makes sense. And it suggests how the NTR version could be better. It is essentially a thrust/ISP tradeoff. With the maximum ISP limiting the final velocity.

========================
Byron,

Nor does the very high acceleration seem like a good thing for guided rounds, and the unknown quantity of hydrogen required might complicate logistics.

----------

I think you could budget the hydrogen. It wouldn't be unknown since you would know how many missiles you have.

You could say 50 shots use X hydrogen, Budget 1.1X and add it as weapon propellant.

Not much different than the extra propellant you have to add for the added mass of laser and radiators for your Laser-Star.

-------

I am unsure of why the high acceleration would be bad for guided rounds necessarily. I would be interested in your thoughts on that.

The acceleration is probably in the 100,000 g's ball park.


(SA Phil)

Anonymous said...

The speed of sound vs temperature for air is in this graph

http://en.wikipedia.org/wiki/File:Speed_of_sound_in_dry_air.svg

So it should follow this pattern. At a high enough temperature the velocity is going to be pretty impressive.

Again, probably related to exhaust velocity as if it were a rocket.

So 8 to 10 kps might be possible.

Of course the velocity you really would want would depend on the scenario of the battle.

However - you could use all this excess heat you hope doesn't incinerate your missile to heat a working fluid onboard the missile.

Which it could then expel to continue accelerating after it was fired.

A thermal-thermal propelled missile.

(SA Phil)

Byron said...

Phil:
I understand the physics behind the various gas guns. No offense, but probably better then you do.
To get 7 km/s, the hydrogen has to be at about 8600K, well above the melting point of anything. For 2.5 km/s, pure hydrogen would need to be at 1092K. Oxygen would reduce that significantly by increasing the molecular weight of the gas. So an NTR-powered gas gun would be limited to about 4 km/s (3000K). That's on the low end of practical weapon velocities, and I'm not sure the difficulties would be worth it. Based on Luke's numbers, that's 160m long, and I think he might have lowballed the numbers slightly. Either way, not a huge advantage. And piping around hot hydrogen? Not fun.
G-load is from here.

Byron said...

Speed of sound scales with the square root of temperature, and with the square root of the inverse of molecular mass. A rocket uses a nozzle to accelerate the exhaust to supersonic speeds. That's not possible here. Adiabatic compression is used in the debris simulators, but that raises a whole host of issues which probably neuter it as a weapon.

Anonymous said...

Hmmm,

Why cant the working fluid temperature exceed the melting point by some controlled amount?

It is expelled rapidly - like a rocket.

A rocket would also melt all its internal components if you held the exhaust there.

I am not sure the piping is going to be all that convoluted - its a tube with a NTR on one end and a hole on the other.

An NTR with a really long rocket nozzle.

(SA Phil)

Anonymous said...

Byron said...

Speed of sound scales with the square root of temperature, and with the square root of the inverse of molecular mass. A rocket uses a nozzle to accelerate the exhaust to supersonic speeds. That's not possible here

===========

Why not?

(SA Phil)

Anonymous said...

I still don't see the G load issue- the linked example is a 1 meter long barrel 0 to 6kps equals 2,000,000 Gs

We are talking a much longer barrel than that and if its "only" 4kps that's quite a bit less.

A 200 meter barrel say -- to make the math easier-- to same 6 kps would be 100,000 G's again.

(not that it is as simple as all that - but I we are just talking a rough concept here)

Or, if the the missile has to survive this really massive 1 million+ G accel wouldn't that also imply it doesn't need the 160 meter+ barrel you describe?

(SA Phil)

Byron said...

NTRs are limited by melting temperature of the fuel elements. 3000K was the first number I came up with. Chemical rockets run hotter, but cooling them is a significant problem. So you can't run an NTR much hotter then that, and the velocity increase goes with the square root of temperature.
The problem with piping is dealing with very hot hydrogen under high pressure. It's not a recipe for happy engineers. If you insist, and are found stabbed to death with a slide rule, it's not my fault. :-)

Byron said...

Oops. Missed a couple more.
Why not?
I'm not entirely sure, but I'm positive that if it would work, they'd use it for light gas guns today. Should be able to get at least 14 km/s out of it then.

G-load is a bit of a stretch given that it's lower-velocity. At the same time, I would expect the barrel to be quite short. In a normal gun, propellant burns most of the way down the barrel. Here, all of the pressure is developed before the projectile even starts to move.

Anonymous said...

Blah mechanical engineers' petty complaints are wasted on me.

Anyway it sounds like you could potentially/plausibly do a 4kps NTR Gas gun anyway, with a couple hundred years improved technology.

Which is better than a current rail gun. So my idea isn't necessarily DOA.

Piping around the hydrogen doesn't necessarily sound any scarier than a 100 MJ laser (and all its heat problems)

(SA Phil)

Anonymous said...

Couldn't control the effective pressure seen by the projectile to an extent by creatively altering the geometry of the barrel/projectile?

Essentially allow the projectile/barrel interface to be a bit leaky.

(SA Phil)

Byron said...

Blah mechanical engineers' petty complaints are wasted on me.
Speaking as an aerospace engineer in training, the slide rule option keeps looking better.

Anyway it sounds like you could potentially/plausibly do a 4kps NTR Gas gun anyway, with a couple hundred years improved technology.
Actually, on farther thought, no. The problem is that the hydrogen needs to be under a lot of pressure, too. That requires pumping and holding it. You will not get anyone to design this thing. It actively needs to be combustion-driven or electrothermal or some such.

Piping around the hydrogen doesn't necessarily sound any scarier than a 100 MJ laser (and all its heat problems)
What you're discussing makes industrial steam sound like fun. And they search for leaks in those systems with a broomstick. When a piece disappears, you've found the leak.

Couldn't control the effective pressure seen by the projectile to an extent by creatively altering the geometry of the barrel/projectile?

Essentially allow the projectile/barrel interface to be a bit leaky.

Maybe. Haven't gotten that far yet. The whole concept is dubious due to the above-mentioned problems.

Anonymous said...

Byron,

I'm not entirely sure, but I'm positive that if it would work, they'd use it for light gas guns today. Should be able to get at least 14 km/s out of it then.

--------

I am pretty sure there is either a 10 or 14 kps Light Gas Gun. But the way they gained the extra velocity involved some sort of "pillow" mentioned in the article which I cant seem to find ATM.

(SA Phil)

Anonymous said...

Byron,

Actually, on farther thought, no. The problem is that the hydrogen needs to be under a lot of pressure, too. That requires pumping and holding it. You will not get anyone to design this thing. It actively needs to be combustion-driven or electrothermal or some such.
-----------

Why does the pressure have to be larger than a NTR? I don't think that part is clear.

In fact the speed of sound part of the problem specifically mentioned it does not vary based on pressure.

(SA Phil)

Byron said...

I am pretty sure there is either a 10 or 14 kps Light Gas Gun. But the way they gained the extra velocity involved some sort of "pillow" mentioned in the article which I cant seem to find ATM.
I found out how they do that. It's firing one gas gun into another, basically. Not practical for a weapon at all. Nothing like a rocket.

Why does the pressure have to be larger than a NTR? I don't think that part is clear.

In fact the speed of sound part of the problem specifically mentioned it does not vary based on pressure.

The pressure is what actually accelerates the projectile. The speed of sound is the fastest the pressure wave can move, and the projectile can't go faster then that.
I think an analogy could be made to surfing (I don't surf, but it sounds right). You can't go any faster then the wave, but if the wave isn't big enough, you just don't go anywhere, no matter how fast it is.
The pressure in an NTR will be quite low. Not enough for what is required here. It simply can't be a steady-state system.

Anonymous said...

So the combustion gun develops its own pressure from the combustion - simplifying the situation, and stretching out the G forces, etc.

The electrothermal gun has pressure from the traditional LGG method and then heats the hydrogen during the firing event. (sounds like)

So instead of the NTR its sounds like you would be better off figuring out how to increase the temperature of the hydrogen in the combustion gun.

Maybe use a laser. heh.

(SA Phil)

Byron said...

The electrothermal gun has pressure from the traditional LGG method and then heats the hydrogen during the firing event. (sounds like)
Actually, skip the ram part, and just run electricity into the gas. But other then that, exactly. Maybe mix it with a combustion gun, but it might be better to avoid adding oxygen.

So instead of the NTR its sounds like you would be better off figuring out how to increase the temperature of the hydrogen in the combustion gun.

Maybe use a laser. heh.

Exactly. Laser could work, but I think you'd be better off just dumping in electricity. No heat losses from the laser machinery.

Anonymous said...

So high power Radio Frequency of some kind for the electro-thermal

Wonder what the limits are? We use RF at work to create plasma.

A plasma combustion gas gun sounds almost Trekian.

(SA Phil)

Byron said...

That would work, though I was thinking some kind of electrical arc, sort of like an arcjet. Either way, it does sound kind of trekkian.

Anonymous said...

I wonder though if the plasma were feasible - could you use magnetic fields to delay how fast your gun melted. (The temperature of the "center" of the plasma/gas would exceed the "edges".

Which could potentially raise your max operating temp. Although it sounds like the physics would be more complicated at that point.

(SA Phil)

Byron said...

I wonder though if the plasma were feasible - could you use magnetic fields to delay how fast your gun melted. (The temperature of the "center" of the plasma/gas would exceed the "edges".
Wait a minute. Your grand scheme to replace magnetic cannons with gas guns has arrive at...magnetic fields. Theoretically possible, probably easier to just build a coilgun.

Anonymous said...

Not quite.

The coil-gun doesn't have the gas(plasma?) doing any work.

So it is quite a bit different.

Although it may be possible the coil-gun is more effective/efficient. Hard to say since the Electro-Thermal Gas/Plasma Gun is just a half formed concept.

It would seem the best geometry for a coil-gun projectile is extremely thin perpendicular to the gun's axis.

While the best geometry of a missile to survive the Laser-Star scenario is long and thin parallel to the guns axis.

Maybe using a coil-gun and having the projectile turn 90 degrees would be the most effective though.

(SA Phil)

Byron said...

Phil:
I know the mechanism isn't the same. The irony just amused me.

jollyreaper said...

Regarding aerospace fighters -- I believe, regardless of the fantasy tech in a setting, should have a performance penalty compared with pure space or atmo fighters. Consider float plane fighters. They certainly had uses but faced a performance penalty vs land and carrier aircraft.

Now perhaps big-ass engines and guided missiles would mean that the aerospace fighter is a lead sled and can hit like a steroid-popping prize fighter but atmo fighters should have access to the same missiles.

Of course, there's a special case for demi-operatic drives. If the fighter uses an antimatter torch that can run at 1.5g's for hours on end, it's just bludgeoning it's way through the air like a missile and doesn't need much more than a few control surfaces. Same engine for space and atmosphere, needs some streamlining but otherwise it's a beast.

In the rifts and void setting, I'm pegging aerospace fighters as two or three times the cost of pure fighters and complex to maintain. They are very useful but there are reasons for building the other kinds of fighters. And concerning aircraft meant to operate solely in atmosphere, fighters that are pure aircraft and require runways are cheaper than ones equipped with antigrav though the antigrav fighters have far greater operational flexibility. There are always trade offs.

As far as a pmf, fighters just won't be manned, I don't see it. And drone weapons are easily expendable. If atmo drones are required, they'll he dropped from space by the carriers in entry capsules. Is there even any use sending them back into orbit? Consider all the war materiel junked after WWII in the pacific, not worth the cost of shipping back home.

In the pmf, aerospace vehicles would tend to be the people carriers. They're the kind of cargo you don't leave behind.

Locki said...

The assumption that detection of hostile forces with IR sensors in rocketpunk and the eponymous atomic rocket sites has always worried me. IR sensors are not great at picking up enemy fighters at range (compared to radar) and there is a wealth of information out there stating why it is so hard to find a Carrier Battle Group with a satellite with IR sensor. The resolution and ability to scan the oceans to target the moving carrier in real time is just not there. Providing useful targetting information to kinetics or lasers at extreme ranges in space can't be any easier. In the real world the USN isn't losing sleep over the possibility. I can't see why detecting a spaceship at extreme ranges should be any easier. (OK background IR is less but the ranges and area that needs to be scanned is far larger).

Which brings me to my second point. A mission kill is a mission kill and the most vulnerable part of all of these warships are the optics for the sensors and (in the case of the laserstars) the optics for the great big honking megawatt lasers. To combat your fearsomely expensive super space dreadnaught laserstar all I have to do it knock out your sensors with much cheaper, lighter blinding lasers.

Huge cryogenically cooled, rapidly panning IR sensors will be easily destroyed by lasers (red wavelength presumably). The high precision optics needed to focus megawatt lasers can be disabled by a much smaller, more efficient blinding laser.


I think its plausable the fear of being blinded (and mission killed) could lead to a semi-stealthy submarine like duel.

The engagement starts with both warships detecting each other at extreme range (outside weapons) and then immediately slamming shut the protective covers over all of their optics to prevent blinding. The ships then maneuver like an elaborate game of marco polo, occassionally peeking through their fingers to get a quick glimpse of the enemies approximate location before blinding lasers can knock out their sensors. Eventually they close to a range where radar is effective a short furious exchange of kinetics, missiles, anti-missiles missiles and point defence lasers finishes the job.

jollyreaper said...

The first place I ever saw counter-battery fire as you describe was in Through Struggle, the Stars. It does make a lot of sense. While it's not so much depicted as submarine combat there, the warships have to be careful about opening combat shutters to prevent their optics from getting burned out. It takes time to repair that sort of damage.

Byron said...

Jollyreaper:
Your analysis matches my own almost exactly. Didn't think about expendable drone fighters. I'm stealing that for the paper.

Locki:
The environment for IR detection in space is vastly different. It's like looking for people with a thermal camera in the arctic. The time taken can be on the order of hours to days, and movement at those timescales is quite small. If you want more details, see Section 2 of my paper.

Blinding is an interesting thought, but things like remote sensor drones can reduce its effectiveness. Also, pointing accuracy and the superiority of pulsed lasers are likely to be problems. Oh, and the blinding lasers will be vulnerable to the big laser far before they can blind it.

The counterbatterys in TSTS are very dependent on high pointing accuracy. Make of that what you will.

Rick said...

Welcome to a new commenter!

Carrier battle groups are hard to find with IR because they are on the surface of a very active planet.

But there's an important corollary: In low orbital space, passing in front of a planet is nearly as good concealment as passing behind it. Sensors optimized to detect and track objects against the dark backdrop of space now have to deal with a backdrop as bright as all outdoors.

In the IR, Earth's night side is one vast glowing sea of 300K heat. All those desperate stealth ideas, like cold gas thrusters, look a bit more promising against such a bright, noisy background.

Anonymous said...

=Milo=



So if not light gas guns, then what does anyone here think of scram cannons? Speculative technology, of course, but the speed of sound doesn't seem to be a limit anymore.



Locki:

"The engagement starts with both warships detecting each other at extreme range (outside weapons) and then immediately slamming shut the protective covers over all of their optics to prevent blinding. The ships then maneuver like an elaborate game of marco polo, occassionally peeking through their fingers to get a quick glimpse of the enemies approximate location before blinding lasers can knock out their sensors."

What if one of the ships doesn't stick to tradition, though? If ship A dutifully shuts its eyes as described while ship B keeps them open, then ship B will have a massive targetting advantage while not actually being in much danger since ship A can't shoot to blind them if they can't SEE them!

Anonymous said...

=Milo=



Rick:

"But there's an important corollary: In low orbital space, passing in front of a planet is nearly as good concealment as passing behind it. Sensors optimized to detect and track objects against the dark backdrop of space now have to deal with a backdrop as bright as all outdoors."

Interestingly, there is a "low ground advantage" here. Invading low-orbit fighters would be much easier to spot from ground-based sensors, since viewed from below you're still set against a backdrop of stars. ...Unless it's daytime. You probably can't afford to make orbital changes every few hours, though, so your course will be reasonably predictable based on once-an-orbital-period sampling.

It's funny really. "Put the sun in your enemy's eyes" is one of the oldest tactics in the book, and it STILL applies.

Similarly low-orbit craft can easily see high-orbit craft (the sun will be an issue less often without atmospheric scattering), but high-orbit craft have a harder time seeing low-orbit craft.

Anonymous said...

Another difference between IR sensors in Space and on Earth is that every environment on Earth is a massive Heat Sink - compared to space.

The source is constantly pumping heat into the cooler air and water around it.

In space it has to radiate it away at some piddling rate.

(SA Phil)

Anonymous said...

Another thought from that Mythbusters show and the survival of the KKV cloud .. And blinding lasers ..

I know that mirror armor is mostly useless -- but what happens to a mirror that is pointed to reflect back a laser's beam 180 degrees?

For a brief moment couldn't it be dazzling the source laser with that laser's own photons?




(SA Phil)

Locki said...

I really do think there could be something to blinding lasers and mounting directed energy weaponary primarily designed to kill sensors rather than punch through armored hulls. The story possibilities are always more interesting if stealth in space can exist - not because its possible to hide your passive emissions - but because no one is brave enough to look!

I believe counter-battery laser fire designed to destroy the sensors or the laser has the advantage over the initial attacker who is just trying to punch a hole through your hull with a big ass laser.

1. The counter battery lasers can be smaller, more efficient and more numerous (eg mounted on drones) than the big main laser designed to punch holes in things.

- eg its much cheaper (in weight and money) for me to neutralise your big main laser with a swarm of smaller counter batter lasers. So yes, your main laser will burn out a few of my blinding lasers whilst we are closing into range (but not too many as I'll keep the protective shutters down) but eventually one of my blinding lasers will get you and then it becomes a kinetic fight.

2. The counter battery lasers require less precise targetting information.

Presumably,the optics needed to create sensitive sensors or very tightly focused megawatt lasers will work in reverse and concetrate any hostile energy hitting the lens and focus it back down to do maximum damage to your own sensitive sensors/laser arrays/CCDs etc. As long as I bathe the general location of the target warship in laser energy of sufficient density to destroy diodes the target lasers own optics (or IR sensor) will do the rest and concetrate the energy back onto its own sensitive array.


On a side note blinding lasers are probably awfully effetive at neutralising super-long range high ISP missile swarms too.


Ironically, all the old tired purple/blue arguments are irrelevent because the best counter to a big honking laser is not a swarm of kinetic missiles but is swarm of smaller, cheaper throwaway lasers.

At the very least my scenario is semi-plausible and may make for a more exciting story setting than the two glass snipers facing off at extreme distances hoping to get the first shot in.

My scenario at least allows for some maneuver warfare. With warships taking a very quick peak at each other on a regular basis to get an approximate location update whilst they try to get in the best position for a kill at close-ish range.

Anonymous said...

Locki,


Ironically, all the old tired purple/blue arguments are irrelevent because the best counter to a big honking laser is not a swarm of kinetic missiles but is swarm of smaller, cheaper throwaway lasers.

===========================

Invoke the Zeroth law - and you have space fighters again.

(SA Phil)

Byron said...

Locki:
I really do think there could be something to blinding lasers and mounting directed energy weaponary primarily designed to kill sensors rather than punch through armored hulls. The story possibilities are always more interesting if stealth in space can exist - not because its possible to hide your passive emissions - but because no one is brave enough to look!
That doesn't even remotely give you stealth in space. It might make it difficult to target you, but the other side has an observer a light-second or two back, radioing your position to the rest of the fleet. It's probably not enough to shoot with, but you're not stealthy.

Presumably,the optics needed to create sensitive sensors or very tightly focused megawatt lasers will work in reverse and concetrate any hostile energy hitting the lens and focus it back down to do maximum damage to your own sensitive sensors/laser arrays/CCDs etc. As long as I bathe the general location of the target warship in laser energy of sufficient density to destroy diodes the target lasers own optics (or IR sensor) will do the rest and concetrate the energy back onto its own sensitive array.
But would it always do that, particularly if you're off-axis? A staring contest with a bigger laser is a bad idea, and shooting off-axis is probably not going to kill the thing.
Also, depending on if the enemy can detect the shutter opening, the time it takes to shoot the laser could be less then light-lag. Which rules counterbattery fire out entirely.

Ironically, all the old tired purple/blue arguments are irrelevent because the best counter to a big honking laser is not a swarm of kinetic missiles but is swarm of smaller, cheaper throwaway lasers.
Not really. The smaller, cheaper lasers will need to be quite large to even stand a chance. That removes them from the throwaway category. Plus, depending on the geometry, they could be quite vulnerable to kinetics themselves.

An alternative to all of this is a phased array. While it's not as good as a standard mirror of the same area, it has a lot of advantages. First and foremost, flexibility. The beam can be split and trained instantly. Also, it's far easier to shutter, as each element can be covered individually. And repair is easy. I'm not even sure the performance would be that much lower. The fact that it's electronic and rigidly mounted would make up for a lot.

Phil:
Do not go there. Please. I've laid out exactly why it won't happen.

Thucydides said...

The big honking laser can blind enemy sensors much farther away than its kill range, so ships and drones carrying less powerful lasers, SCoDs or crossbows, for that matter, will be at a disadvantage.

As well, lasers have multiple kill mechanisms depending on how they are operated; a pulse laser will deliver a large amount of energy in a very short time frame, which might be the equivalent to being struck with a hammer. Damage will occur before there is any possibility of heat energy being radiated away. Even a mirror pointed back at the attacking laser might shatter or craze when it intercepts the initial pulse.

On a different point., Rick opened this piece by noting how battleship design became standardized relatively quickly among all the seagoing powers. There were some interesting divergences from the "battleship norm", mostly to do with the Washington Naval Treaty.

The Royal Navy, hamstrung by financial distress, did some interesting work arounds to maximize firepower and minimize armoured volume in order to have hard hitting ships that they could afford and that were inside the treaty. The "N" class Battleships and the "G" class Battlecruisers, although never built, were the apogee of this process. Two battleships, the HMS Nelson and HMS Rodney, were actually laid down and were very close to the N and G class designs (mounting all three big gun turrets on the foredeck, just ahead of a "tower" bridge).

The point is we have been arguing essentially in a friction free environment (which is good; we can see the logical end points of some of these arguments), but the designers of real spacecraft (regardless of the mission they are designed for) may be constrained by outside influences like finances, treaties or even time (if the Imperial Jovian Navy has been slowly building up their navy over a period of years while the Uranus Space Navy has been static due to their internal politics, they may have to embark on a crash program that sacrifices many "nice to haves" in order to get enough ships in service.

Anonymous said...

Byron said:"That's what a shutter is for. It doesn't require a turret. Actually, a turret isn't even all that useful in preventing debris damage out of combat. There's a good chance that at least a little bit of stuff would leak through."

Unless your shutters are heavily armored, then the armored side of a turret is going to give you much better protection.

Byron said:"You missed the point. There is no reason whatsoever that a space-based aerospace fighter would fight in space. The penalty of the airframe and engine required to get back to orbit would leave it at a tremendous disadvantage when compared to a dedicated space fighter, to say nothing of a regular warship. Any mass spent on fighting outside the atmosphere is a penalty inside it, and vice versa. Designing for both is going to end up with something that's low-performance, expensive, and difficult to maintain. I'm not sure what else to say."

Oh, I know that purpose-built pure space orbital fighters and purpose-built pure atmosheric fighter would have a better proformance in there respective enviornments, (and I'm not advocating not building them), there are situations where you will need both capabilities, but can only be able to carry X number; either carry half as many of each as you need (or less for the atmo fighters; you have to be able to get them to the surface), or carry X number of aerospace fightes; either a reduced performance or not enough, a trade-off either way.

I said:"Which will be different for different sets of circumstances; state a scenario and we'll be able to come up with battle plans to fit the limitations and goals."
Byron said in reply:
"To some extent, yes. On the other hand, there are a lot of circumstances when you just need to put a hole in something far away. And the military does have to deal with the problem of not being able to customize a vessel for every task. For a lot of jobs, a laserstar works just fine. It may not be the best possible, but it does a lot of things pretty well."

I never said that we needed to customize ships to meet evey circustances, just that there shouldn't be a dependancy on a very limited number of highly specilized ship-types.

Also, on a side note, not spelling my name right gives the impression that you're not really paying attention to what I'm saying.

Ferrell

Tony said...

Byron:

"We obviously don't agree on where that line is. I'm done here."

I'm not wishful thinking-away real world constraints. You are.

"As an example of cost, I'll use numbers from my spreadsheet, which contains the best PMF numbers I can come up with. A 100 MJ pulsed laser generator which fires every 10 seconds is $800 million and 144 tons. The accompanying mirror is about 20 meters, and 20 tons, and costs about 800 million. None of these seem terribly out of line for a major warship today, much less in the future. CVN-78 is supposed to be about 13 billion."

And is totally mooted if you can't ge much effective range out of it.

"What do you mean, not useful for much? It will destroy things. That's the point of a weapon."

Uhhh...no. The point of a weapon is to apply force effectively. Destroying things is only effective if you are shooting at pureply military targets and can destroy enough things fast enough.

"Because there is lots of junk that happens to be passing within the threat envelope of the vessel at high velocity, and of the appropriate size. According to NASA, there are about 21,000 pieces of debris larger then 10 cm in orbit. How often is one of those pieces likely to come within the threat envelope of the vessel in question? Once an hour, if that? Burn it and be done."

I'm not talking about just tracked space junk in orbit. There's also a lot of stuff that nobody suspected until we started looking at the top of the Earth's atmosphere with real time video. Turns out that a lot of sutff hits the Earth all of the time, at interplanetary velocities. All of that stuff would be within the threat envelope of something that can engage at fractional light second ranges. And you can't just write off stuff not on direct collision trajectories, because one can't rule out maneuverable kinetics. I think the defensive shooting would be pretty regular. That will wear out systems, increase heat load (because you can't shed the heat all at once) and cost a lot of money in power system fuel.

"Depends on the size of the carrier, doesn't it. If the lasers are limited to the $250 million range (which gives me 30 MJ every 10 seconds and 11.5 meter mirrors) then a carrier and parasites could well be more expensive. From the same sheet, a 100 MW thrust power electric drive and reactor is about $600 million. Remember those vaunted economies of scale from Space Warfare XIII? How do those affect the fighters?"

Well, aside from the fact that your numbers are totally speculative...well, no reason to go further than that. If they are correct, it would be the first time in history AFAIK that the maximally effective weapon system would actually be the cheapest.

"I mean that it might be theoretically possible to build a one primary laser vessel that is smaller then the maximum practical. Even though the scaling laws are against it, it's better then, say, a group of fighters of equal cost."

Mmmmhmmm...

Anonymous said...

Byron,

Phil:
Do not go there. Please. I've laid out exactly why it won't happen.

------------

Wouldn't the same argument apply to "line of battle" drones though?

If one works the other could potentially work.

So I didn't really go there- Locki did, I just pushed the concept a bit.

I can see neither working of course.

(SA Phil)

Anonymous said...

Thucydides said...

Even a mirror pointed back at the attacking laser might shatter or craze when it intercepts the initial pulse.

================

I was counting on the mirror being destroyed quickly- I just was wondering if it would be an effective dazzler between the time it was hit and the time it was destroyed/degraded.

The way I envision the cloud of KKVs is anything you can do to slow the laser's destruction of the cloud - Both the more likely the cloud will kill the laser - And the smaller the cloud has to be.

The same applies to how fast the cloud is moving - the better the closing velocity the faster the laser has to be.

(SA Phil)

Byron said...

Ferrell:
Unless your shutters are heavily armored, then the armored side of a turret is going to give you much better protection.
If you skip the turret, you have more mass to put in the shutter.

Oh, I know that purpose-built pure space orbital fighters and purpose-built pure atmosheric fighter would have a better proformance in there respective enviornments, (and I'm not advocating not building them), there are situations where you will need both capabilities, but can only be able to carry X number; either carry half as many of each as you need (or less for the atmo fighters; you have to be able to get them to the surface), or carry X number of aerospace fightes; either a reduced performance or not enough, a trade-off either way.
This assumes that for some reason, you can only carry X fighters, without regard to mass or cost. This is not a situation that is likely to occur. I would be unsurprised if dedicated aerospace and space fighters of the same performance were half the mass of the combined version, and less then half the cost. Each part has to carry the other, which is a viscous cycle.

I never said that we needed to customize ships to meet evey circustances, just that there shouldn't be a dependancy on a very limited number of highly specilized ship-types.
Why is a laserstar so specialized? It's no more specialized then a battleship, and they certainly built those.

Also, on a side note, not spelling my name right gives the impression that you're not really paying attention to what I'm saying.
My apologies. I am paying attention. I just disagree quite strongly with the hybrid fighters for design reasons.

Tony said...

Thucydides:

"Since high power lasers have already been demonstrated tracking and hitting targets from aircraft in flight and warships at sea, the engineering problems of scale, isolating vibrations and target tracking can be taken as solvable."

Non sequitur. Hitting an outboard motor at a thousand meters or a ballistic missile at a few hundred kilometers is not the same technical problem as hitting even a hundred meter long spaceship at several tens or hundreds of thousands of kilometers.

Anonymous said...

Tony,

Hitting an outboard motor at a thousand meters or a ballistic missile at a few hundred kilometers is not the same technical problem as hitting even a hundred meter long spaceship at several tens or hundreds of thousands of kilometers.

-------------

This is true, but it might be something akin to advanced optics and pointing requirements used in observing astronomical objects.

IE- the Hubble might be the first set of data points for a centuries long feasibility study into the application of Lasers in space combat.

(SA Phil)

Tony said...

Rick:

"The point of the spherical cow version is simply to be a starting point for thinking about the military use of big lasers. Not to be the final word on the subject."

I wouldn't disagree with that, in principle. But so many people take the starting point as being the final word, not just about lasers, but about everything. And no, I don't think that's unfair, when you have people who genuinely believe that there's nothing that can ever compete with lasers in space, and anybody who disagrees is iether some kind of idiot or just a habitual contrarian.

"If long-range laser weapons turn out to be non-viable, discussing their characteristics is moot. But my gut feeling is that laying down an effective zap to several thousand km will turn out to be practical."

It wouldn't surprise me if that turned out to be a fact. But that's a long way from fractinal light second ravening heat rays of death. But let's look at that number "several thousand" as a practical measure. Let's further say that in the PMF one could get a closing velocity of 25 kps on a kinetic swarm. Finally, let's say that a laserstar can discriminate and engage the swarm at 10k km. That works out to 400 seconds to successfully engage several hundred targets. That sounds to me like a tall order, when a single hit is enough to at least get a mission kill.

"There is no military-level effort, today, to detect that stuff. A major ship or constellation will have a robust scan suite."

But how robust is robust enough? You can't field a constellation of Hubbles as a military capability. That's one of the arguments in favor of small scout/attack craft to begin with.

"And to modify a contemporary naval aphorism, don't scan for the arrows, scan for the archers. Once you are tracking the archers it will be a lot easier to detect any arrows they shoot."

Not if the arrows are below your detection capability until they are relatively close.

Anonymous said...

Byron,

Why is a laserstar so specialized? It's no more specialized then a battleship, and they certainly built those.

------------

A Battleship is practically a generalist compared to something like a Bomber. Which can do one thing - drop bombs.

The Laser-Star shooting stuff with lasers seems to be in the same category.

Bombers seem to still be popular.

(SA Phil)

Tony said...

Byron:

"I'm not sure you'd need a turret. The ship should be able to turn just fine."

How long do you have to wait between training events for internal vibrations to settle out? That's a big problem that's always ignored in these discusions. A turreted mirror might actually be easier to stabilize after a pointing shift.

But then we have the big problem with all laser mirrors that is also seemingly always ignored. People make all of their laserstarlicious calculations based on optically perfect mirrors. Real world physical optics aren't like that, so there is some degree of degredation built-in right there.

Also, because real world optics aren't perfect, they aren't perfectly reflective. The more energy you pump into them, the more energy they absorb. That leads to heat deformation, which spreads out the beam. That limits effective range. Or one tries to actively cool the mirror, but induced vibrations also spread out the beam, limitting effective range.

Just more reason to be skeptical of the fractional light second laser weapon.

Anonymous said...

RE: KKV cloud / individual Missile detection.

Hmm,

I think I am liking the IR/Visual transparent missile idea again.

If it is transparent it will have a smaller footprint to any active LIDAR scans.

It will also effectively radiate heat "faster" (Because the whole missile is effectively a radiator) meaning they would want to use those scans more often to compensate for the passive image being a bit fuzzier.

(SA Phil)

Tony said...

SA Phil:

"A Battleship is practically a generalist compared to something like a Bomber. Which can do one thing - drop bombs.

The Laser-Star shooting stuff with lasers seems to be in the same category.

Bombers seem to still be popular."


Bombing is still popular. The means of delivering bombs has been switched from dedicated level or dive bombers to multi-mission strike aircraft that can even be used in aerial combat.

We should also remember that the whole purpose of air power is to deliver bombing attacks. Fighters and EW aircraft are just there to enable your own strike aircraft and oppose enemy strike planes. In that sense, the laserstar, if such a thing ever existed, would be nothing more than a fighter -- it's entire job would be to protect outgoing strikes and disrupt incoming ones. Uh-oh...

Byron said...

Tony:
I'm not wishful thinking-away real world constraints. You are.
Yes. Because anyone who disagrees with you is obviously ignorant of reality, instead of holding a different opinion about a somewhat subjective matter. Does the word arrogant ring any bells?

Uhhh...no. The point of a weapon is to apply force effectively. Destroying things is only effective if you are shooting at pureply military targets and can destroy enough things fast enough.
And what other role do kinetics play that makes them so superior?

All of that stuff would be within the threat envelope of something that can engage at fractional light second ranges. And you can't just write off stuff not on direct collision trajectories, because one can't rule out maneuverable kinetics. I think the defensive shooting would be pretty regular. That will wear out systems, increase heat load (because you can't shed the heat all at once) and cost a lot of money in power system fuel.
Because the chances of someone randomly deciding to start shooting out of the blue are so high. I would point out that most spacecraft protection research is focused on space debris, not on meteors. I'd assume that's because the debris is a greater threat. The envelope of a powered kinetic is fairly small on these sorts of scales. Engage anything passing within a kilometer, and keep an eye on the rest.

Well, aside from the fact that your numbers are totally speculative...well, no reason to go further than that. If they are correct, it would be the first time in history AFAIK that the maximally effective weapon system would actually be the cheapest.
How are we comparing cost? Is it the cost to carry a given cost of weapons systems? Is it the cost to carry a given amount of firepower, due to the scaling factors of lasers? The second one would probably be the way a design study would go. And for that, the laserstar is a clear winner.

Byron said...

Tony, cont.:
I wouldn't disagree with that, in principle. But so many people take the starting point as being the final word, not just about lasers, but about everything. And no, I don't think that's unfair, when you have people who genuinely believe that there's nothing that can ever compete with lasers in space, and anybody who disagrees is iether some kind of idiot or just a habitual contrarian.
That has never been the point. At the same time, the laserstar has some impressive numbers behind it, and with some (admittedly optimistic) technical assumptions, it comes out looking quite potent.
Also, you seem to go the opposite way. According to you, lasers have virtually no practical use outside of maybe blinding opponents.


It wouldn't surprise me if that turned out to be a fact. But that's a long way from fractinal light second ravening heat rays of death. But let's look at that number "several thousand" as a practical measure. Let's further say that in the PMF one could get a closing velocity of 25 kps on a kinetic swarm. Finally, let's say that a laserstar can discriminate and engage the swarm at 10k km. That works out to 400 seconds to successfully engage several hundred targets. That sounds to me like a tall order, when a single hit is enough to at least get a mission kill.
This assumes that a single laserstar is the only defense involved. Things like Kirklin mines or other vessels might tip the balance a bit. It's not a guaranteed victory for either side.

But how robust is robust enough? You can't field a constellation of Hubbles as a military capability. That's one of the arguments in favor of small scout/attack craft to begin with.
The attack part still makes no sense. What does it attack? How does it survive?
Also, the scan environment throws you a significant bone. Almost everything starts at a planet. Track it, classify it, throw a telescope on it occasionally. Use spies or drones for close observation. Full sky scans are actually not really needed.

Not if the arrows are below your detection capability until they are relatively close.
Maybe. But if you know where to look, it's probably a lot easier to find them. And given modern BMD radars, I don't find tens of thousands of kilometer ranges that outlandish.

Anonymous said...

Even using your interpretation it is not only a fighter - it is also an Anti-aircraft gun.

Which also were built.

And air-defenses are popular.

"Fighters" (of any size, even if capital ships) are also needed to protect you from other ships.

(SA Phil)

Byron said...

Tony, part 3:
But then we have the big problem with all laser mirrors that is also seemingly always ignored. People make all of their laserstarlicious calculations based on optically perfect mirrors. Real world physical optics aren't like that, so there is some degree of degredation built-in right there.
I've been using imperfect mirrors for over a year. Cut the range from optical perfection by at most a factor of 10. Or maybe you want to claim my fudge factors aren't high enough again.

How long do you have to wait between training events for internal vibrations to settle out? That's a big problem that's always ignored in these discusions. A turreted mirror might actually be easier to stabilize after a pointing shift.
That depends heavily on the size of the turret. Or just use a phased array.

Phil:
The engineering of making transparent missiles is likely to be a major pain. Plus, will the material remain transparent when it starts taking damage? You'll lower the maximum range, but most damage takes place at close range.

A Battleship is practically a generalist compared to something like a Bomber. Which can do one thing - drop bombs.

The Laser-Star shooting stuff with lasers seems to be in the same category.

Bombers seem to still be popular.

What does a battleship do?
Shoot at other warships. Check.
Shoot at land targets. Provisionally check. The wavelength and type of laser might influence this.
Defend carriers from aircraft. No good comparison, so I'll use kinetic defense. Also check. Assuming a decent detection range, the laserstar kills faster then anything else.

The problem with the 180 degree mirror (which would actually involve a corner reflector) is that the beam would be very dispersed by the time it got back. Even assuming that the reflectivity was perfect, the intensity would drop by a factor of 4. Typical corner reflectors would probably scatter the signal more then that, dropping intensity farther. It might be possible to make the very precise, but is it really worth the effort?

Anonymous said...

Byron,


The problem with the 180 degree mirror (which would actually involve a corner reflector) is that the beam would be very dispersed by the time it got back. Even assuming that the reflectivity was perfect, the intensity would drop by a factor of 4. Typical corner reflectors would probably scatter the signal more then that, dropping intensity farther. It might be possible to make the very precise, but is it really worth the effort?

--------------

I only primarily want to dazzle the laser killing the mirror - so even a drop off in power of 10X or more probably is acceptable.

Ideally you could also cause the Laser-Star to heat up - slowing its effective duty cycle killing the cloud.

I was thinking the pusher plate/conductor for the accelerator gun could also make a temporary mirror.

It doesn't have to work all that well-- it is mainly just there for noise and to give the Laser something to shoot at.

(SA Phil)

Brett said...

@Byron
The environment for IR detection in space is vastly different. It's like looking for people with a thermal camera in the arctic.

I'm not convinced that's the case for any plausible inter-planetary or interstellar civilization. Unless you're positing a Killing Star hypothesis with a fleet arriving out of nowhere to attack, any sort of inter-planetary space warfare is probably going to take place in an environment where there are a bunch of civilian spaceships flying around.

In that case, your attacking ships would just have to avoid looking out of the ordinary from the rest of the space traffic. That might even favor smaller numbers of big ships, since a huge honking fleet flying in the direction of Earth is going to look more suspicious than a big ship like the other big ships hauling stuff between the planets.

Anonymous said...

Byron,

The engineering of making transparent missiles is likely to be a major pain. Plus, will the material remain transparent when it starts taking damage? You'll lower the maximum range, but most damage takes place at close range.

---------------

*If it is harder to track it will slow the rate the Laser Kills targets.

*If it is transparent to frequencies the laser operates at it will only absorb some of the energy of the laser - passing the rest. Slowing down the rate it will take damage and be destroyed. It doesn't have to be immune to laser fire - just slow the laser down so another missile gets through.

*I have a feeling engineering said missile wont be any harder than engineering a 100 MJ Space Based Laser. High optical Grade Quartz, mostly transparent semi-conductors, electrically conductive diamond -- all are identified technologies.

The Laser-Star's effectiveness is based on how many missiles it can kill in a given time. So the Kinetic side engineers are going to be looking for ways to influence those variables.

(SA Phil)

Tony said...

Byron:

"Yes. Because anyone who disagrees with you is obviously ignorant of reality, instead of holding a different opinion about a somewhat subjective matter. Does the word arrogant ring any bells?"

Thing is, it's not a subjective matter. There are always constraints that disallow maximal theoretical performance. YOu give them some lip service, but you assume that whenever you need a capabiloity, you'll have it, simply because you want it. I'm perfectly sanguine to leave it up to the reader who's being more unreasonable.

"And what other role do kinetics play that makes them so superior?"

They can carry high explosives, for one thing, or chemical weapons, or nukes, or whatever seems like a useful capability that can't be carried by pure photons.

"Because the chances of someone randomly deciding to start shooting out of the blue are so high. I would point out that most spacecraft protection research is focused on space debris, not on meteors. I'd assume that's because the debris is a greater threat. The envelope of a powered kinetic is fairly small on these sorts of scales. Engage anything passing within a kilometer, and keep an eye on the rest."

When do you decide it's going to pass outside of a kilometer? At ten thousand kilometers, a fractional gee of thrust for only a few seconds could change a miss to an impact. At even a thousand kilometers it doesn't take that much delta-v. Basically everything that comes within a very large cone along your trajectory is a potential threat.

"How are we comparing cost? Is it the cost to carry a given cost of weapons systems? Is it the cost to carry a given amount of firepower, due to the scaling factors of lasers? The second one would probably be the way a design study would go. And for that, the laserstar is a clear winner."

Actually, that's not how costs are figured at all. One has to factor the actual cost of the total weapon system, not just the gun. The battleship as a total weapon system was extremely expensive, because it wasn't just a hull, guns, and some propulsion. There were sensors, fire control computers, communications systems, secondary armament, etc. Or look at the expense that the Aegis system and associated weapons adds to US cruisers and destroyers.

The laserstar is going to be a ridiculously expensive exercise for just a single gun -- not so much in terms of the gun itself, but in the complexity and precision of the support systems that will make that gun effective at specified long ranges. Yet another thing you seem to either be unaware of, or wilfully ignore.

Anonymous said...

Brett said...

@Byron
The environment for IR detection in space is vastly different. It's like looking for people with a thermal camera in the arctic.

I'm not convinced that's the case for any plausible inter-planetary or interstellar civilization. Unless you're positing a Killing Star hypothesis with a fleet arriving out of nowhere to attack, any sort of inter-planetary space warfare is probably going to take place in an environment where there are a bunch of civilian spaceships flying around.

In that case, your attacking ships would just have to avoid looking out of the ordinary from the rest of the space traffic. That might even favor smaller numbers of big ships, since a huge honking fleet flying in the direction of Earth is going to look more suspicious than a big ship like the other big ships hauling stuff between the planets.

=========================

All those other ships wont be traveling the same vector as the opposing fleet.

Nor likely to be in the same general vicinity.

I think that all the ships "out there" on your side will have transponders.

Although I am sure mistakes will happen - just like they do with radar on Earth.

(SA Phil)

Anonymous said...

=Milo=



SA Phil:

"I know that mirror armor is mostly useless -- but what happens to a mirror that is pointed to reflect back a laser's beam 180 degrees?

For a brief moment couldn't it be dazzling the source laser with that laser's own photons?"


That only works if the mirror is exactly 180 degrees to the beam, which is going to be very hard to pull off.

You could have a round mirror or non-mirror white surface that reflects in all directions, but that's highly unlikely to send enough photons back in the right direction to do any damage.

Besides, what's the point of dazzling the enemy AFTER you got shot?

They obviously already know where you are.



Locki:

"The story possibilities are always more interesting if stealth in space can exist - not because its possible to hide your passive emissions - but because no one is brave enough to look!"

The problem is that sensors aren't useful if you don't use them.

Keeping your sensors intact, at the expense of not getting use of those sensors, is an exercise in pointlessness.

What you're more likely to do expose some sensors while keeping others in reserve, so the enemy can't fry them all at once. Keep an eye on the enemy so you can shoot them, then if you get blinded, replace the sensor.

Even if all your shots are accomplishing is blinding the enemy's sensors back, then you're losing no more than you're gaining. IF your shots are doing anything more than that, then it was a really good decision to take the shot, wasn't it?



Ferrell:

"Unless your shutters are heavily armored, then the armored side of a turret is going to give you much better protection."

Unless your turrets are heavily armored, then an armored shutter is going to give you much better protection.



Tony:

"And you can't just write off stuff not on direct collision trajectories, because one can't rule out maneuverable kinetics."

No, but you can limit yourself to stuff within a certain angular range.

A missile that's going fast enough to be a threat isn't just going to suddenly make a 90-degree turn.


"In that sense, the laserstar, if such a thing ever existed, would be nothing more than a fighter -- it's entire job would be to protect outgoing strikes and disrupt incoming ones."

Well, yes. I don't think anyone ever claimed that laserstars are effective troop landing craft.

The fact is still that fighters are what you use to gain air superiority, and other air force activities generally need you to already have air superiority to be effective. If laserstars work the same way in space, they'll definitely be a mainstay of planets' space forces, and possibly the only ones designed for space-to-space combat rather than orbit-to-surface combat. (Though low orbit might be a third theater next to surface and deep space.)



SA Phil:

"Even using your interpretation it is not only a fighter - it is also an Anti-aircraft gun."

An anti-aircraft gun is an assymetric weapon, attacking air targets from a non-air platform.

A fighter attacks air targets from an air platform. A laserstar attacks space targets from a space platform.



Brett:

"In that case, your attacking ships would just have to avoid looking out of the ordinary from the rest of the space traffic."

Traffic is likely to be regulated, so you'll also need to give the relevant authorities a convincing cover story for what your ship's civilian mission is supposed to be.

Also, this kind of trick only works in a surprise attack. Once war or near-war antagonism breaks out between planets, they'll probably stop or severely limit civilian traffic between the planets, so any violations of the embargo can be assumed to be either invaders or smugglers (either way, zap away!).

Anonymous said...

RE: massive debris and other space noise.

If orbital debris near "Earth" orbit are going to be such a confusion, then position the Laser-Star farther way. Then it only has to worry about new debris either moving towards "Earth" or moving towards the Laser-Star.

The debris that are not part of an attackers KKV swarm won't be changing course to match this more clear position.

The angles of these attacks aren't going to be like battles on Earth. There is a massive difference between a missile that can hit 20 or 100 miles away and weapons that are engaging thousands of kilometers out.


(SA Phil)

Tony said...

Byron:

"That has never been the point. At the same time, the laserstar has some impressive numbers behind it, and with some (admittedly optimistic) technical assumptions, it comes out looking quite potent.

The problem is that those technical assumptions are ridiculously optimistic, from my POV. Please try to understand, my personal experience of the real world combat environment makes me highly skeptical of anything coming even close to theoretical capabilities. I can't stuff that experience into your head. But I think you should let my skepticism based on it -- and not just on that experience, but on years of reading military and technical history that confirms it -- give you much more pause than you're exhibiting.

"Also, you seem to go the opposite way. According to you, lasers have virtually no practical use outside of maybe blinding opponents."

Now that's a malicious exageration, B. You should be ashamed of yourself. I'm simply skeptical of effective laser weapon ranges above a few thousand kilometers, using practical systems.

"This assumes that a single laserstar is the only defense involved. Things like Kirklin mines or other vessels might tip the balance a bit. It's not a guaranteed victory for either side."

It assumes nothing outside ordinary military competence. If one has multiple laserstars to attack, a competent planner will attack them simultaneously, at least to the degree that they can provide each other mutual support.

"The attack part still makes no sense. What does it attack? How does it survive?"

It attacks any assigned objective. It survives probably about as well as any other attack craft does, per mission -- not too well, but enough will come back for further taskings.

"Also, the scan environment throws you a significant bone. Almost everything starts at a planet. Track it, classify it, throw a telescope on it occasionally. Use spies or drones for close observation. Full sky scans are actually not really needed."

Spies and drones. Yeah, right. Like the opposition is not going to clear its planetary skies of enemy observation drones. Like a spy's reports are going to be relevant in tactical time.

Also, the expense of constant high definition surveilance at planetary distances is not going to be cheap. We're still talking constant tasking of a Hubble+ instrument just for surveillance, then you have to add more instruments of similar power for spot checking.

"Maybe. But if you know where to look, it's probably a lot easier to find them. And given modern BMD radars, I don't find tens of thousands of kilometer ranges that outlandish."

Picking up everything bigger than golf ball within that volume. We're back to target discrimination capabilities.

Anonymous said...

Tony,

They can carry high explosives, for one thing, or chemical weapons, or nukes, or whatever seems like a useful capability that can't be carried by pure photons.

---------------
I don't see it.

All those things are meant to wreck things. The Laser wrecks things.

Bullets wreck things - they don't have additional utility either.

The whole "you wouldn't build X weapon because it can only blow things up with it" seems like a dumb argument.

What are swords for? To hack people up. You cant use them to plow fields.

(SA Phil)

Tony said...

Byron:

"I've been using imperfect mirrors for over a year. Cut the range from optical perfection by at most a factor of 10. Or maybe you want to claim my fudge factors aren't high enough again."

You still don't seem to be taking operational heating into effect.

"That depends heavily on the size of the turret. Or just use a phased array."

Either you're not listening or not comprehending. Any moving structure introduces vibration. A small structure will vibrate a lot, and take longer to settle out. A larger structure will vibrate less, but be harder to position precisely. Either way, you're adding time ot each engagement.

And phased arrays will creat vibration in every array element.

Tony said...

SA Phil:

"I don't see it.

All those things are meant to wreck things. The Laser wrecks things.

Bullets wreck things - they don't have additional utility either.

The whole 'you wouldn't build X weapon because it can only blow things up with it' seems like a dumb argument.

What are swords for? To hack people up. You cant use them to plow fields.


Maybe I don't want to poke holes in things. Maybe I want to destroy them outright. Bombs (and missiles) are still popular, right?

Anonymous said...

RE: poking holes

The Laser is going to do more than poke holes.

Put a thin piece of steel in a fixture and slice it with a 200 watt laser. It is an extremely violent event. 2 billion watts? Just poking holes? Yeah right.

If all it did was poke holes the KKV cloud planner's job would be easy. The missiles would just have to look like card tables with randomly placed "legs" (the rocket parts with redundancy)

The Laser would have to poke hole after hole until it poked a hole somewhere important.

(SA Phil)

Byron said...

Brett:
I'm not convinced that's the case for any plausible inter-planetary or interstellar civilization. Unless you're positing a Killing Star hypothesis with a fleet arriving out of nowhere to attack, any sort of inter-planetary space warfare is probably going to take place in an environment where there are a bunch of civilian spaceships flying around.
There are certain behavior patterns to military vessels. For one thing, it's likely that a vessel's class could be identified from her drive flare. So the vessel has to have the right torch and mass for the commercial vessel it's imitating. And this isn't the 18th century, so there isn't going to be a surprise visit by a trading fleet. To pull off some sort of attack, you would have to have a group of vessels arrive at once that you can somehow replace without alerting anyone. That strikes me as unlikely.

Phil:
The difficulty and cost added are unlikely to be worth it. Get a small "scorch laser" which is absorbed by, say, the wires. That makes a mission kill really easy.

Tony:
Thing is, it's not a subjective matter. There are always constraints that disallow maximal theoretical performance. YOu give them some lip service, but you assume that whenever you need a capabiloity, you'll have it, simply because you want it. I'm perfectly sanguine to leave it up to the reader who's being more unreasonable.
I'm assuming that with technical advances and good engineering, we can get within maybe a factor of 4 to 10 of diffraction-limited range performance. What would be reasonable numbers? 100? 1000?

They can carry high explosives, for one thing, or chemical weapons, or nukes, or whatever seems like a useful capability that can't be carried by pure photons.
Except for nukes, those are only good for bombarding planets. I've always said that kinetics would be integrated. Possibly in the form of, say, a few missiles on a laserstar? Or a dedicated kentistar?

When do you decide it's going to pass outside of a kilometer? At ten thousand kilometers, a fractional gee of thrust for only a few seconds could change a miss to an impact. At even a thousand kilometers it doesn't take that much delta-v. Basically everything that comes within a very large cone along your trajectory is a potential threat.
What does that mean? If it looks at any point to be heading within a kilometer of me, it's a threat. If it materially changes its trajectory at any point, it's a threat.

Actually, that's not how costs are figured at all. One has to factor the actual cost of the total weapon system, not just the gun. The battleship as a total weapon system was extremely expensive, because it wasn't just a hull, guns, and some propulsion. There were sensors, fire control computers, communications systems, secondary armament, etc. Or look at the expense that the Aegis system and associated weapons adds to US cruisers and destroyers.
And again, how does this make fighters cheaper? Assuming that electronics (which is what everything except secondary armament listed above is) are a very significant portion of the cost is bad for fighters. Also, the carrier will probably have a similar electronics fit to the battleship. Or the battleship wouldn't have said electronics in the first place.

The laserstar is going to be a ridiculously expensive exercise for just a single gun -- not so much in terms of the gun itself, but in the complexity and precision of the support systems that will make that gun effective at specified long ranges. Yet another thing you seem to either be unaware of, or wilfully ignore.
Maybe so. But why would multiple guns be better? Even if the laserstar can't hit anything at its theoretical maximum range, it is still more powerful at shorter ranges.

Anonymous said...

Byron,

Phil:
The difficulty and cost added are unlikely to be worth it. Get a small "scorch laser" which is absorbed by, say, the wires. That makes a mission kill really easy.

--------

I don't need any "wires" the control electronics could all be largely transparent - including the conductors, and the antennas.

The entire electronics portion can also be in a high temperature heatsink/coolant - which is also transparent.

The definition of "easy" is the entire point.

Lets say you have two missiles - both have the same mass.

One is a wimpy aluminum missile it takes 1 second to track and kill.

The other is a Optical Quartz missile- it takes 3 seconds to track and kill.

In that scenario for the given mass of kinetics the Quartz missile is 3 times as effective as the aluminum missile.

If your aluminum cloud were only half the size it needed to be to kill the laser - the comparable quartz storm would be 150% the size it needed to be, dead laser.

(SA Phil)

Byron said...

Tony, cont.:

The problem is that those technical assumptions are ridiculously optimistic, from my POV. Please try to understand, my personal experience of the real world combat environment makes me highly skeptical of anything coming even close to theoretical capabilities. I can't stuff that experience into your head. But I think you should let my skepticism based on it -- and not just on that experience, but on years of reading military and technical history that confirms it -- give you much more pause than you're exhibiting.

I can respect that you view my numbers as overoptomistic. I would remind you that we are dealing with technology that is centuries in the future, and in an environment that is quite clean by military standards. Current astronomy levels of precision do not seem at all out of place.

Now that's a malicious exageration, B. You should be ashamed of yourself. I'm simply skeptical of effective laser weapon ranges above a few thousand kilometers, using practical systems.
Yes. I was frustrated. My apologies.

It assumes nothing outside ordinary military competence. If one has multiple laserstars to attack, a competent planner will attack them simultaneously, at least to the degree that they can provide each other mutual support.
So it's going to take a really big cloud of kinetics to take out even a Tony-approved laserstar. What was that supposed to prove?

It attacks any assigned objective. It survives probably about as well as any other attack craft does, per mission -- not too well, but enough will come back for further taskings.
This is a total nonanswer. What sort of objectives would this scout/attack vessel be assigned to attack? Given that it's some sort of parasite, it's obviously not too powerful relative to major warships. So it goes after lightly defended targets. And what lightly defended targets would there be at sufficient distances from the fleet that it couldn't go there itself, or just use a missile?

Spies and drones. Yeah, right. Like the opposition is not going to clear its planetary skies of enemy observation drones. Like a spy's reports are going to be relevant in tactical time.
Something along the lines of "These guys have brought all of the ships that are going to be visiting in May into the yard, and haven't explained why. Also, all the cargo for the May visit was canceled."
And a drone could very well be quite a ways off in interplanetary space. Oh, and killing the drones. Major tip-off that something is up. It's entirely possible that powers would allow each other to position drones in their orbits as part of a treaty to ensure the other guy isn't preparing a sneak attack.

Picking up everything bigger than golf ball within that volume. We're back to target discrimination capabilities.
Target discrimination? If there's a sudden spike in the debris background, then you're under attack. Start shooting at the most likely objects, then keep shooting until the coast is clear. I'm still a bit skeptical of this constant interplanetary object rain of yours, but I absolutely refuse to believe that it's big enough to hide a major attack. At least until you show me some numbers.

Anonymous said...

Also - even if the missile is "mission killed" - the Laser can't read its mind.

It will still be tracking an inbound missile. One that either needs to be diverted or destroyed.

Frying a control wire wont do that. Thus the laser will still need to play around with shooting at it. Wasting critical time it should be using to kill another missile with a working control system.

(SA Phil)

Anonymous said...

Byron,

I'm still a bit skeptical of this constant interplanetary object rain of yours, but I absolutely refuse to believe that it's big enough to hide a major attack. At least until you show me some numbers.

------------------

I am also highly skeptical of the "rain" of missiles and other spacecraft (from Brett's example)

Space is mostly empty. It should be pretty easy to define a near empty area for the Laser-Satr to work from.

If there are a few debris that would interfere - the Laser can zap them long before the battle.

Just like marines clearing away brush surrounding a fire base.

(SA Phil)

Anonymous said...

*missiles should read debris in my previous post.

(SA Phil)

Byron said...

Phil:
I don't need any "wires" the control electronics could all be largely transparent - including the conductors, and the antennas.

The entire electronics portion can also be in a high temperature heatsink/coolant - which is also transparent.

Shoot a laser at a frequency absorbed by some important element of the missile. It is flatly impossible to avoid that weakness. And if you've been very nice to me, there's no armor in the way.

It will still be tracking an inbound missile. One that either needs to be diverted or destroyed.

Frying a control wire wont do that. Thus the laser will still need to play around with shooting at it. Wasting critical time it should be using to kill another missile with a working control system.

So you make a small burn, and it goes flying by. Big deal.

Tony:
You still don't seem to be taking operational heating into effect.
No, I'm using a fudge factor that is my best guess at how well the laser will work. That includes everything.
Heating can be resolved in three ways. First, make a bigger mirror. Second, use adaptive optics. Third, use a pulsed laser, and cool the mirror between shots.

Either you're not listening or not comprehending. Any moving structure introduces vibration. A small structure will vibrate a lot, and take longer to settle out. A larger structure will vibrate less, but be harder to position precisely. Either way, you're adding time ot each engagement.

And phased arrays will creat vibration in every array element.

Maybe the number in my spreadsheet called "jitter" is meant to take vibration into account. I'm not going to debate the exact magnitude with you again.

Anonymous said...

Byron,

Shoot a laser at a frequency absorbed by some important element of the missile. It is flatly impossible to avoid that weakness. And if you've been very nice to me, there's no armor in the way.

-----------------
There is quartz armor. Try to match the frequencies of the other components as best you can.

How easy will it be to vary the frequency of the big honking laser?

Lasers are designed to operate at a specific frequency aren't they?

=============

So you make a small burn, and it goes flying by. Big deal.

=============

You make a small burn and I win. You wasted time. Now you need to compensate for the burn before you fire the next shot.

But still you are ignoring the fact that you wont know the missile is unguided if it is still intact and not deflected.

The missiles could come in mostly ballistic so there is no way to tell between a live and a "dead" control system.

The vector changes are going to be pretty small -- everything is coming at the Laser-Star in straight lines.

(SA Phil)

Tony said...

Byron:

"I'm assuming that with technical advances and good engineering, we can get within maybe a factor of 4 to 10 of diffraction-limited range performance. What would be reasonable numbers? 100? 1000?"

The answer depends on too many variables to be figured that way. The thing is identifying the critical capability, defined as the one that limits your effective range the most. It could be your ability to discriminate. It could be that passive kinetics are spinning, and take a while to zap. It could be that constant firing degrades you precision through heat deformation of your optical train. It could be that your active cooling of your powr supply intoduces so much vibrational energy that you simply can't settle on a target more than x-number of microradians in angular width. It could be so many things -- and likely every single one, in some combination. Naming a fudge factor is just about as bad a speculative move as disregarding engineering constraints altogether.

THe point to be made is that engineering constraints exist, they're much more complex than laserteers give them credit, and they're handwaved away.

"Except for nukes, those are only good for bombarding planets. I've always said that kinetics would be integrated. Possibly in the form of, say, a few missiles on a laserstar? Or a dedicated kentistar?"

I would think laserstars, if practical at all, would be escorts for the actual strike craft.

"What does that mean? If it looks at any point to be heading within a kilometer of me, it's a threat. If it materially changes its trajectory at any point, it's a threat."

If a few hundred seemingly random kinetics materially change their trajectory only a few thousand kilometers away, What do you do then? Or do you blast everything big enough to hurt you as soon as it enters your engagement envelope? Target acquisition is only half the battle -- not even half. Accurate target identification is the real problem over laserstar kinds of ranges.

"And again, how does this make fighters cheaper? Assuming that electronics (which is what everything except secondary armament listed above is) are a very significant portion of the cost is bad for fighters."

Since when? You have fighters precisely because they can get relatively cheap sensors close.

"Also, the carrier will probably have a similar electronics fit to the battleship. Or the battleship wouldn't have said electronics in the first place."

Sorry, but that's incorrect. The carrier needs sensors for local defense. It has the fighters for closer inspection of long range targets. The battleship, of necessity, has to have the maximum sensor suite, because itself is all it has.

"Maybe so. But why would multiple guns be better? Even if the laserstar can't hit anything at its theoretical maximum range, it is still more powerful at shorter ranges."

Not if it can be overwhelmed with cheap kinetics launched beyond laser engagment range.

See, what you're doing here is assuming a priori that it cannot be overwhelmed by kinetics in some way. You were talking about arrogance earlier. What is arrogance and what is humility in that case, hmmm?

Anonymous said...

also I could have missiles with different frequency weaknesses. (to an extent)

So even if the laser star can vary the laser frequency it would need to guess for each one.

That or pick a laser frequency that will be a weakness all the time - placing a design restraint on the entire laser system.

(SA Phil)

Byron said...

Tony:
THe point to be made is that engineering constraints exist, they're much more complex than laserteers give them credit, and they're handwaved away.
Or maybe we give future engineers more credit then you do. Vibration and deformation can be dealt with through beam quality. This is where the running of numbers comes in. If the cooling system uses, say, thermal superconductors, most of the vibration disappears. Spinning projectiles are most effective against CW lasers.

I would think laserstars, if practical at all, would be escorts for the actual strike craft.
So both sides throw kinetics, and then what? The laserstars clean up afterwards? This is a revelation how? Most people would describe it the other way around, but it's nothing new.

If a few hundred seemingly random kinetics materially change their trajectory only a few thousand kilometers away, What do you do then? Or do you blast everything big enough to hurt you as soon as it enters your engagement envelope? Target acquisition is only half the battle -- not even half. Accurate target identification is the real problem over laserstar kinds of ranges.
This assumes that there are normally a few thousand pieces of random space junk of the appropriate size coming from the correct direction, so the kinetics get lost in the noise. I have yet to find a good distribution for objects of that size, but I'm going to say that it's nowhere near that high. If you believe otherwise, show me the numbers.

Sorry, but that's incorrect. The carrier needs sensors for local defense. It has the fighters for closer inspection of long range targets. The battleship, of necessity, has to have the maximum sensor suite, because itself is all it has.
It still has to detect and classify those targets. Launching fighters for inspection is a massive waste of delta-V. A small, unmanned drone could do the job just as well.

Not if it can be overwhelmed with cheap kinetics launched beyond laser engagment range.

See, what you're doing here is assuming a priori that it cannot be overwhelmed by kinetics in some way.

No, it can be overwhelmed. However, it's far more difficult to overwhelm a laserstar then it is to do the same to a similar cost of carrier and fighters. It is simply the most survivable platform available.


also I could have missiles with different frequency weaknesses. (to an extent)

So even if the laser star can vary the laser frequency it would need to guess for each one.

That or pick a laser frequency that will be a weakness all the time - placing a design restraint on the entire laser system.

And your cost just went up again. Missiles playing dead works just as well for conventional missiles, and they don't require a bunch of exotic technologies, which will undoubtedly raise the price significantly. Not to mention that the sensor is by definition an absorber of whatever it sees in.

Tony said...

Byron:

"I can respect that you view my numbers as overoptomistic. I would remind you that we are dealing with technology that is centuries in the future, and in an environment that is quite clean by military standards. Current astronomy levels of precision do not seem at all out of place."

Current astronomy levels of precision are based on using the Earth as a solid instrument base or, in the case of orbital telesacopes, moving the instrument very slowly and giving it plenty of time to settle down before observing.

Now, the problem with the "clean"ness of the space environment is that you don't have a planet to absorb vibrations, or any other way to put mechanically induced vibrations overboard. Add the maneuvering and quick slewing of the combat environment, and I'd be surprised if adequate collimation could be maintained over more than a few thousand kilometers. That makes the laser a medium range gun at best.

"So it's going to take a really big cloud of kinetics to take out even a Tony-approved laserstar. What was that supposed to prove?"

No. It's going to take seperately targetted attacks to take out multiple, mutually supporting laserstars, just like it would take separately targetted attacks to take out multiple, mutually supporting AAA positions. It's a common and well understood planning and logistics issue, that's all.

"This is a total nonanswer. What sort of objectives would this scout/attack vessel be assigned to attack? Given that it's some sort of parasite, it's obviously not too powerful relative to major warships. So it goes after lightly defended targets. And what lightly defended targets would there be at sufficient distances from the fleet that it couldn't go there itself, or just use a missile?"

Most targets are lightly defended, Byron. In any target array in history. Even heavily defended targets aren't uniformly defended. The Japanese, for example, used HE against the Russian battleships at Tsushima because they were more sure that a ship would catch fire than be penetrated in a vital spot by AP. Turns out they were right. A laserstar dealing with thousands of ball bearings dropped by a half dozen parasites at 10k km is in a world of hurt.

"Something along the lines of 'These guys have brought all of the ships that are going to be visiting in May into the yard, and haven't explained why. Also, all the cargo for the May visit was canceled.'"

And that's useful in tactical time how?

"And a drone could very well be quite a ways off in interplanetary space. Oh, and killing the drones. Major tip-off that something is up. It's entirely possible that powers would allow each other to position drones in their orbits as part of a treaty to ensure the other guy isn't preparing a sneak attack."

In interplanetary warfare, one wouldn't tolerate enemy drones within effective sensor range, same as no nation today would tolerate military overflights. Remember, we're talking about completely unified planets in total sovereign control of their own orbitals and surrounding space.

Tony said...

Byron:

"Target discrimination? If there's a sudden spike in the debris background, then you're under attack. Start shooting at the most likely objects, then keep shooting until the coast is clear. I'm still a bit skeptical of this constant interplanetary object rain of yours, but I absolutely refuse to believe that it's big enough to hide a major attack. At least until you show me some numbers"

According to The Wiki, the power law of 5cm to 300m objects hitting the Earth per year is:

N(>D) = 37 * D^-2.7

where:

D is the diameter of a given object in meters, and

N(>D) is the number of objects larger than D likely to hit the Earth per year

So let's say a 10cm object is considered dangerous by your targetting system. Then the probability of objects just slightly large than 10cm hitting the Earth (supposing that's the body you're defending) would be:

37 * .01^-2.7
~= 9.3M/yr
~= 25,400/day

If you take into account a KKV's ability to maneuver, several targets per minute are likely threats to a laserstar that considers anything with 10,000km a threat. That's just nature shooting at you.

Tony said...

Byron:

"[the laserstar] is simply the most survivable platform available."

Thanks for boiling it down for me. To me this is simply an unsubstantiated article of faith.

Byron said...

No. It's going to take seperately targetted attacks to take out multiple, mutually supporting laserstars, just like it would take separately targetted attacks to take out multiple, mutually supporting AAA positions. It's a common and well understood planning and logistics issue, that's all.
You are dodging the issue. The simple fact is that even your analysis suggests that a lot of kinetics are required to take out a laserstar. That is the entire point.

Now, the problem with the "clean"ness of the space environment is that you don't have a planet to absorb vibrations, or any other way to put mechanically induced vibrations overboard. Add the maneuvering and quick slewing of the combat environment, and I'd be surprised if adequate collimation could be maintained over more than a few thousand kilometers. That makes the laser a medium range gun at best.
Let's think about this. Last year, I said 250 nr was a bottom-end jitter estimate. This is significantly more then Hubble, but it's two orders of magnitude less then the ALL. Why? No aerodynamic loads, no thrust loads, no engine vibration, no vibration from moving chemicals in the laser, the crew is strapped in... Built it right, and I don't see numbers on the order of tens of nanoradians being at all outrageous. That could easily pass 10,000 km in range.

Most targets are lightly defended, Byron. In any target array in history. Even heavily defended targets aren't uniformly defended. The Japanese, for example, used HE against the Russian battleships at Tsushima because they were more sure that a ship would catch fire than be penetrated in a vital spot by AP. Turns out they were right. A laserstar dealing with thousands of ball bearings dropped by a half dozen parasites at 10k km is in a world of hurt.
No, it isn't. At that sort of range, either the laserstar can dodge, or the cloud spreads enough to reduce the density to something manageable. Also, you assume that a ball bearing is a significant threat to a laserstar. Armoring against that isn't too difficult. And vaporizing a ball bearing takes next to no time.

And that's useful in tactical time how?
It's not. However, you also don't need Hubble in tactical time. The discussion started with blending in to civilian traffic, which doesn't happen overnight.

In interplanetary warfare, one wouldn't tolerate enemy drones within effective sensor range, same as no nation today would tolerate military overflights. Remember, we're talking about completely unified planets in total sovereign control of their own orbitals and surrounding space.
We use satellite overflights for arms control verification. This is exactly the same thing. I wasn't speaking of a time when all-out warfare had broken out, but before that. When war is going on, figuring out what is inside something that looks like a merchant ship is sort of pointless.

Byron said...

Tony:
(Math on meteor power law)
First, how did I miss that part of the article.
Second, those numbers are for a 1-cm object. The correct number for a 10-cm object is 50.8 per day. That is with the entire earth as a target.
I'm going to try some speculative math. Taking half the earth's surface area, that comes out to 1 object per day per 5,023,360 km^2. Or one object per day in a circle 2530 km across. Any attack will be quite obvious.
Third, you still don't get how the threat tracking system works. If the object is on a trajectory that will take it within some "threat zone" then it is destroyed. The threat zone is defined as the radius at which it could light a booster and deflect onto an intercept course that would leave insufficient time to kill it. Assuming some sort of high-speed turret is fitted (or a phased array or some such) reaction time is likely to be on the order of 10 seconds, which in turn means that a radius of maybe 100 km is required.
Creeping in is easy to foil as well. Anything passing within 1000 km has its trajectory logged and occasionally cross-checked. Any deviation, particularly towards the ship, gets it fried. And there's just not a lot of stuff to hide in.
Running the numbers for 2.5 cm objects gives 2144 per day. That in turn comes out to about one per hour passing through the defense zone. The math isn't perfect, but it's a far cry from massive clouds of stuff coming from all sides.

Thanks for boiling it down for me. To me this is simply an unsubstantiated article of faith.
So what would be more survivable? Honestly curious.

Tony said...

Byron:

"You are dodging the issue. The simple fact is that even your analysis suggests that a lot of kinetics are required to take out a laserstar. That is the entire point."

Whoever said it wouldn't take a large number? I never did. And I'm not dodging anything. I'm simply pointing out that every time you attemp to introduce some kind of "So there!" wrinkle, it's nothing of the kind, just another tactical problem that competent commanders have long been familiar with, sometimes just in broad outline, sometimes in pretty specific detail.

ganbatte!

"Let's think about this. Last year, I said 250 nr was a bottom-end jitter estimate. This is significantly more then Hubble, but it's two orders of magnitude less then the ALL. Why? No aerodynamic loads, no thrust loads, no engine vibration, no vibration from moving chemicals in the laser, the crew is strapped in... Built it right, and I don't see numbers on the order of tens of nanoradians being at all outrageous. That could easily pass 10,000 km in range."

No aerodynamic loads? Check.

No thrust loads? Perhaps, dependinging on whether you're relying on guns alone or on guns and dodging.

No engine vibration? Sorry, power plant vibration.

No vibration from moving chemicals in the laser? Even if you specify a solid state laser, your lasing material is going to undergo thermal stress and deformation, which will have to be absorbed by some kind of cooling system. (It's not perfectly transparent.) Also, it turns out that solid state lasers work better at lower temperatures. More cooling system vibrations.

You specified no mirror turrets, just whole-vessel pointing. All kinds of vibrations induced there, especially at militarily useful training rates.

Even turreted mirrors have (some pretty obvious) vibration issues.

Changing orientation (of either the whole vessel or just a turret) induces heat expension and contraction, as you change what the sun is shining on. If you're in orbit, just passing in and out of the planet's shadow is going to induce thermal stress vibration in the structure.

Finally, mirrors are going to thermally deform under firing stresses. Even if it was cooled between shots, as you suggested, one would have to wait for the vibrations induced by the between-shots cooling system to settle out. Or simply wait a longer between shots.

"No, it isn't. At that sort of range, either the laserstar can dodge, or the cloud spreads enough to reduce the density to something manageable. Also, you assume that a ball bearing is a significant threat to a laserstar. Armoring against that isn't too difficult. And vaporizing a ball bearing takes next to no time."

A ball bearing at a hundred kps (remember, the kinetic bus can be dropped at any time in the interplanetary trajectory, not just on the final approach) can do enough damage to cause at least a mission kill. And if you expend enough energy per shot to vaporize each potential hazard in "next to no time", you'll heat deform your optics to the point that you won't be able to hit a battleship after about ten or twelve shots.

Tony said...

Byron:

"It's not. However, you also don't need Hubble in tactical time. The discussion started with blending in to civilian traffic, which doesn't happen overnight."

???

"We use satellite overflights for arms control verification. This is exactly the same thing. I wasn't speaking of a time when all-out warfare had broken out, but before that. When war is going on, figuring out what is inside something that looks like a merchant ship is sort of pointless."

We're not talking about the Cold War. We're talking about an environment in which a planet has sovereign control over its surrounding space. Random freighters not going anywhere would be boarded and inspected. Drones doing nothing but watching would be (legally, and without starting a war) destroyed, just like an unannounced foreign overflight would be today.

Byron said...

Tony:
No engine vibration? Sorry, power plant vibration.
This powerplant, designed for the laserstar, compares with a jet engine how? A little bit, but not much, and well-insulated.

No vibration from moving chemicals in the laser? Even if you specify a solid state laser, your lasing material is going to undergo thermal stress and deformation, which will have to be absorbed by some kind of cooling system. (It's not perfectly transparent.) Also, it turns out that solid state lasers work better at lower temperatures. More cooling system vibrations.
I did miss this one. Though design and lower magnitudes will still reduce the total load significantly.

You specified no mirror turrets, just whole-vessel pointing. All kinds of vibrations induced there, especially at militarily useful training rates.
By the time high training rates become necessary, the vibrations induced will be less of a problem.

A ball bearing at a hundred kps (remember, the kinetic bus can be dropped at any time in the interplanetary trajectory, not just on the final approach) can do enough damage to cause at least a mission kill. And if you expend enough energy per shot to vaporize each potential hazard in "next to no time", you'll heat deform your optics to the point that you won't be able to hit a battleship after about ten or twelve shots.
You specified parasites at 10k km. That sort of precludes 100 km/s velocities, unless you're using a torch of some sort. Also, the fighters can't really stop in time unless they use chemfuel. Which limits velocity to something like 10 km/s at most. And if the fighters have a torch, then so does the laserstar, which ups the ball bearing count again.

We're not talking about the Cold War. We're talking about an environment in which a planet has sovereign control over its surrounding space. Random freighters not going anywhere would be boarded and inspected. Drones doing nothing but watching would be (legally, and without starting a war) destroyed, just like an unannounced foreign overflight would be today.
What about a drone sitting outside the hill sphere, in international space? It might take some fuel, but it can spend some time there. We never destroyed Soviet trawlers during the cold war, even though we knew full well what they were doing. I was suggesting that under certain circumstances, powers might agree by treaty to station observation posts in each others territory to defuse tensions.

Tony said...

Byron:

"(Math on meteor power law)..."

Dropped a decimal place. How stupid of me.

"So what would be more survivable? Honestly curious."

Don't know. Don't care.

The point I'm making is that throughout the history of war, all measures have always had countermeasures. You were talking about arroagance earlier. To me, it's pure arrogance to suggest that some real world, practical measure cannot possibly have a real world, practical countermeasure. On the other hand, to me it's simple humility to accept that nothing is truly superior and everything has some exploitable vulnerability.

To me talking about specific engineering constraints and the principles of war is just discussing the mechanics of vulnerability. The ultimate "why" in my opinion is simply that nothing has ever been so stupendously awesome as the laserstar seems to be in a lot of people's minds, and nothing is ever likely to be.

Anonymous said...

=Milo=



SA Phil:

"I don't need any "wires" the control electronics could all be largely transparent - including the conductors, and the antennas."

So you need a bunch of sufficiently transparent materials with all sorts of different material properties. They also need to be transparent to every possible wavelength, especially higher wavelengths like ultraviolet and X-rays, which are the most useful for space-based lasers.



Byron:

"And a drone could very well be quite a ways off in interplanetary space."

"What about a drone sitting outside the hill sphere, in international space?"

Drones in interplanetary space spend a significant amount of their time very far away from anything important.

Drones supposed to be able to keep an eye on a planet are going to be in L1/L2 points at the very highest.


"Shoot a laser at a frequency absorbed by some important element of the missile. It is flatly impossible to avoid that weakness. And if you've been very nice to me, there's no armor in the way."

That's true. Transparancy and armor are mutually incompatible goals.

(Indeed, the biggest drawback of armor-piercing munitions is that they tend to overpenetrate and not deliver all their energy to the intended target. Meanwhile munitions specifically designed to not overpenetrate are really poor against armor.)



SA Phil:

"There is quartz armor."

That's missing the point. To be effective, armor has to absorb energy from the attack to spare that energy from hitting more critical components.


"How easy will it be to vary the frequency of the big honking laser?

Lasers are designed to operate at a specific frequency aren't they?"


Depends on the laser type. Some can vary more easily than others.



Tony:

"The thing is identifying the critical capability, defined as the one that limits your effective range the most."

The way to do that is to identify all limits and quantify them, then see which is the worst.

As a bonus, since you've already calculated them you can now also include the minor limitations in your results as well as the major ones, fine-tuning your accuracy.


"I would think laserstars, if practical at all, would be escorts for the actual strike craft."

So what are the strike craft striking, and what are the laserstars escorting them against?


"Then the probability of objects just slightly large than 10cm hitting the Earth (supposing that's the body you're defending) would be:"

Spaceships are smaller than the planet Earth.


"If you take into account a KKV's ability to maneuver, several targets per minute are likely threats to a laserstar that considers anything with 10,000km a threat."

Why would it consider an object that's projected to miss it by 9999 km a threat?

Even if the missile somehow carries enough delta-vee to change such a wide miss into a hit, which I find unlikely, the course adjustment burn will necessarily happen when it's still at least 9999 km away, so you have plenty of time to respond to the course correction and zap it after all.



Byron:

"Also, you assume that a ball bearing is a significant threat to a laserstar. Armoring against that isn't too difficult."

Anything is a threat if it's coming in fast enough.

Byron said...

The point I'm making is that throughout the history of war, all measures have always had countermeasures. You were talking about arroagance earlier. To me, it's pure arrogance to suggest that some real world, practical measure cannot possibly have a real world, practical countermeasure. On the other hand, to me it's simple humility to accept that nothing is truly superior and everything has some exploitable vulnerability.
Most of the discussion here is about countermeasures and counter-countermeasures. We don't know where the balance between them will fall. Which means that ruling out laserstars is a bit premature. Maybe kinetics will dominate. Maybe lasers will. But claiming that laser dominance or even parity is impossible due to practical concerns seems slightly odd. The vulnerability is the fact that with enough firepower it can be overwhelmed. So? The same is true of anything ever. The question is how much firepower, and what can we do to increase or decrease that amount.

To me talking about specific engineering constraints and the principles of war is just discussing the mechanics of vulnerability. The ultimate "why" in my opinion is simply that nothing has ever been so stupendously awesome as the laserstar seems to be in a lot of people's minds, and nothing is ever likely to be.
So you admit that lots of people have oversold the laserstar, but that it might have a place, depending on tech assumptions. Is it inevitable? No. Is it totally impractical? No. Why are we arguing again?

Byron said...

Milo:
Anything is a threat if it's coming in fast enough.
True. But relativistic ball bearings are likely to be rare in the PMF. I was assuming some moderate closure rate, on the order of 20 to 30 km/s. Even at that velocity, it should be possible to avoid mission-kill from a few ball-bearings.

Tony said...

Byron:

"This powerplant, designed for the laserstar, compares with a jet engine how? A little bit, but not much, and well-insulated."

It puts vibrationsal energy into the system, by it's cooling plant, if nothing else. You can't insulate it at all well, because you can't put it on a separate base, like you can a similar system on a planet. Just like a jet engine on a 747, your power plant is aboard, and the vessel structure absorbs it's vibrations. And you can't insulate the laser from the vessel structure, because the vessel's dimensions are defined by your laser generator's dimensions.

"I did miss this one. Though design and lower magnitudes will still reduce the total load significantly."

One can't design away the fact that the cooling system has to exist and operate at some high degree of efficiency (which means fluid transfer, as far as we know). It will make appreciable noise.

"By the time high training rates become necessary, the vibrations induced will be less of a problem."

Huh? High training rates in this instance would be a mil a second in this application. Once you get the whole vessel started, ya gotta stop the whole vessel, and settle it down in the new shooting direction. One might solve this partially by setting up a slow rotational moment and shoot as one bears. But that limits you to shot's within a plane, and then you still have to take time to stop the rotation ans get it going another way, through another plane, every few seconds. Lot's of vibrations caused by all of that maneuvering.

"You specified parasites at 10k km. That sort of precludes 100 km/s velocities, unless you're using a torch of some sort. Also, the fighters can't really stop in time unless they use chemfuel. Which limits velocity to something like 10 km/s at most. And if the fighters have a torch, then so does the laserstar, which ups the ball bearing count again."

Non sequitur. One only has to achieve the necessary velocity and vector. The carrier goes off on a trajectory that passes the target planet at a safe distance. The fighters launch at the optimum range, then use their limited maneuverability to attain a rendezvous trajectory with their carrier. Or do a gravity well maneuver on the target planet.

"What about a drone sitting outside the hill sphere, in international space? It might take some fuel, but it can spend some time there. We never destroyed Soviet trawlers during the cold war, even though we knew full well what they were doing. I was suggesting that under certain circumstances, powers might agree by treaty to station observation posts in each others territory to defuse tensions."

Why would one consider the Hill shpere to be the natural limit of international space? The limits of international waters were set by effective weapons ranges. I see no reason why in space sovereign entities wouldn't set the limit at effective sensor range, for some specified class of sensor (the one above which sensors just get so expensive, that you can't use them in constant surveillance).

Tony said...

Byron:

"Most of the discussion here is about countermeasures and counter-countermeasures. We don't know where the balance between them will fall. Which means that ruling out laserstars is a bit premature. Maybe kinetics will dominate. Maybe lasers will. But claiming that laser dominance or even parity is impossible due to practical concerns seems slightly odd. The vulnerability is the fact that with enough firepower it can be overwhelmed. So? The same is true of anything ever. The question is how much firepower, and what can we do to increase or decrease that amount."

Thing is Byron, I always try to say precisely what I mean. You should try reading precisely what I say. When I say "real world, practical", that's precisely what I mean. "Practical", in the ral world, isn't defined by some absolute balance. It's defined by what one can pay and what one is willing to pay.

So to me some figure x-number of kinetics of y-mass at z-velocity to effectively attack a laserstar is totally, desperately uninteresting to me. It's enough to know that whatever the number is, it is probably within the practical capabilities of whoever has to attack a laserstar and has an economy to match that of the laserstar builder to begin with.

"So you admit that lots of people have oversold the laserstar,"

I've said it. I think it's for you to admit it -- if any admissions are necessary. You're the one so doggedly defending the concept, as if it could never be oversold.

"but that it might have a place, depending on tech assumptions. Is it inevitable? No. Is it totally impractical? No. Why are we arguing again?
"


Ummm...I have a real hard time seeing how it could ever be practical. It just seems like it's a sitting duck, waiting to be overwhlemed by a relatively easily mounted kinetic attack. And that seems to me to be a constantly scalable result, across broad areas of assumption. The larger and more effective you make it in its own defense, the more expensive it becomes, and the fewer you can build. So it takes a more effective kinetic attack to neutralize one, but it also takes fewer of these larger attacks to address a smaller fleet. Slide your way up and down the scale, it seems to me to be the same. It's just too much technology existing in one package, existing primarily to defend itself. (Because it can only engage in other missions after it has exhausted all attacks designed to take it out of the order of battle as a (very obvious) first move.)

Byron said...

Tony:
I'm not going to do specific vibration sources. There will be some. How much is unknown. Neither of us is really qualified to speculate on the magnitudes involved.

Non sequitur. One only has to achieve the necessary velocity and vector. The carrier goes off on a trajectory that passes the target planet at a safe distance. The fighters launch at the optimum range, then use their limited maneuverability to attain a rendezvous trajectory with their carrier. Or do a gravity well maneuver on the target planet.
How does this work again? If the parasites are at 10,000 km and 100 km/s, traveling directly towards the target, the most they can miss by, assuming that there are humans on board limiting them to 10Gs, is 500 km. If the laserstar is doomed, it's likely to laser them out of spite. If it's not, then it hits them when the ball bearings are past. Either way, they're dead. And slowing down from 100 km/s will almost require a torch, even if someone else gets you there.

Why would one consider the Hill shpere to be the natural limit of international space? The limits of international waters were set by effective weapons ranges. I see no reason why in space sovereign entities wouldn't set the limit at effective sensor range, for some specified class of sensor (the one above which sensors just get so expensive, that you can't use them in constant surveillance).
Why wouldn't you use the hill sphere. It provides a nice, neat boundary with an actual rationale (anything inside is orbiting you anyway). International waters were based off cannon range, not how far someone could see. Even leaving aside your views on scanning (which are not shared by most people, and would result in chaos if implemented using the normal views on the subject) having a very large moving bubble would be a nightmare to deal with for everyone. What happens when it crosses a route between two other bodies? Or if an asteroid being mined by power A drifts into Power Bs bubble. Not to mention the chaos in a system with multiple moons. Also, given that nations on earth are used to being observed by satellite, why would they suddenly become paranoid about privacy?

So to me some figure x-number of kinetics of y-mass at z-velocity to effectively attack a laserstar is totally, desperately uninteresting to me. It's enough to know that whatever the number is, it is probably within the practical capabilities of whoever has to attack a laserstar and has an economy to match that of the laserstar builder to begin with.
And it's within the practical capabilities of a number of countries to build enough missiles to sink a carrier. We still have those, don't we. The fact that a vessel can be killed by cheaper weapons does not render it utterly obsolete.

Byron said...

I've said it. I think it's for you to admit it -- if any admissions are necessary. You're the one so doggedly defending the concept, as if it could never be oversold.
It can be oversold. I've never supported the multi-light-second ravening beam of death. That doesn't mean it isn't the optimal design for a standard warship under tech assumptions that are based on such a concept existing. Which is a bit of a stretch, but assuming that space warfare is anything more then nuclear war in space requires it.

Ummm...I have a real hard time seeing how it could ever be practical. It just seems like it's a sitting duck, waiting to be overwhlemed by a relatively easily mounted kinetic attack. And that seems to me to be a constantly scalable result, across broad areas of assumption. The larger and more effective you make it in its own defense, the more expensive it becomes, and the fewer you can build. So it takes a more effective kinetic attack to neutralize one, but it also takes fewer of these larger attacks to address a smaller fleet. Slide your way up and down the scale, it seems to me to be the same. It's just too much technology existing in one package, existing primarily to defend itself. (Because it can only engage in other missions after it has exhausted all attacks designed to take it out of the order of battle as a (very obvious) first move.)
Is it just me, or did you just describe the battleship under torpedo attack, and the carrier under missile attack? Both are far cheaper then the target, but the target in question still got built.
On a more meta level, two swarms of kinetic vessels shooting at each other has no purpose whatsoever. They each fire their munitions and die. Game over. Thus, if we are to have space war to discuss, it must include something more. That would be something that resembles a conventional warship. Logic applied to lasers results in the laserstar.
So yes, you gain the crown of ultimate realism. Enjoy it, but remember that most people don't enjoy nihilism in their space warfare.

Locki said...

Byron said:

But would it always do that, particularly if you're off-axis? A staring contest with a bigger laser is a bad idea, and shooting off-axis is probably not going to kill the thing.
Also, depending on if the enemy can detect the shutter opening, the time it takes to shoot the laser could be less then light-lag. Which rules counterbattery fire out entirely.

Not really. The smaller, cheaper lasers will need to be quite large to even stand a chance. That removes them from the throwaway category. Plus, depending on the geometry, they could be quite vulnerable to kinetics themselves.

______________________

With all due respect I don’t think people have thought through the issues of the extreme vulnerability of high performance lasers and sensors to being blinded. This is effectively a mission kill in a modern space environment. If you can blind (kill sensors) or defang( kill lasers) your opponent with a minimum of effort there is no need to go punching holes through ceramic-diamond armor.

The IR sensors and mirrors (or phased arrays) of the target ship are an order of magnitude more vulnerable to laser energy than is the ceramic armored shutter. A 20 metre diameter laser is a huge target. An IR sensing array the size of hubble is only slightly less vulnerable. Without crunching the numbers my guess it would take over 1000 times the energy to burn through an armored shutter rather than just the energy to burn out the vulnerable sensors/optics.

You can think of lasers having two ranges. A very long distance “blinding range” at which it can knock out sensors and opposing lasers and a second much shorter “burning range” at which it can effectively burn through armor.

So an unshuttered laser (actively firing)or an unshuttered IR sensing array (actively looking) is terribly vulnerable.
To neutralise the laserstar you merely need two smaller,cheaper lasers whose “blinding range” exceeds the laserstars “burning range”.

Without doing the math presumably what this means is I can build two lasers of 1/1000th the size of your laser star of doom. After getting a quick fix on the laserstars position both advance towards the laserstar with their optics and sensors shuttered.
The Laserstar of doom and its mega deathray begin firing at extreme “blinding range” to suppress my 2 ships but this doesn’t worry either of my two small cheap ships since their optics are shuttered.

I don’t even have to fix the position of the laserstar anymore since its kindly broadcasting its position away like a lighthouse in a storm.

Now as long as the “blinding range” of my two smaller ships exceeds the “burning range” of the laserstar the laserstar loses. Yes the laserstar can suppress one of my ships with its huge laser (it doesn’t dare unshutter its optics if its being actively fired upon) but the other ship gets a free shot.

Theoretically the laserstar is in even more trouble since I can probably afford to build 1000 smaller ships for every single laserstar of yours.

I’ve never been a fan of overwhelming superior tech with swarms. But if you think about the physics of my scenario it only requires that I outnumber your laserstars by a single ship (eg 3 on 2) for me to overwhelm your laserstars with shuttered warships intent on blinding you.

By way of belated introduction I’ve been lurking for years so I’m assuming spirited “discussion” is tolerated around rocketpunk even for new posters. Forgive me if I offend.

But in all respect what caused me to delurk was the fact this blog has seemed to come around to a certain consensus opinion on laserstars and doesn’t seem to be genuinely considering other possibilities. Everything about rocketpunk is theoretical.

Tony said...

Byron:

"How does this work again? If the parasites are at 10,000 km and 100 km/s, traveling directly towards the target, the most they can miss by, assuming that there are humans on board limiting them to 10Gs, is 500 km. If the laserstar is doomed, it's likely to laser them out of spite. If it's not, then it hits them when the ball bearings are past. Either way, they're dead."

You'd probably use the fighters to place the kinetic busses in the correct trajectory, then go on to accomplish other missions in orbital space as they pass through it. I know I said the fighters would drop at 10k km, but I didn't think things all the way through. Also, I was triying to evoke my estimation of effective laser range, not the range where I thought a tactical release necessarily needed to be made. No reason not to drop them at 100k km, or even 1M km.

"And slowing down from 100 km/s will almost require a torch, even if someone else gets you there."

Who's slowing down? You're just shifting awya from and back to an established interplanetary trajectory over days or weeks. The carrier's drive does all the big time delta-ve maneuvers.

"Why wouldn't you use the hill sphere."

Because it's arbitrary, WRT sensor effectivenness.

"International waters were based off cannon range, not how far someone could see. Even leaving aside your views on scanning (which are not shared by most people, and would result in chaos if implemented using the normal views on the subject)"

What are my views on scanning, exactly? I don't think I've ever articulated them -- or you mean something different by scanning than I do.

"having a very large moving bubble would be a nightmare to deal with for everyone. What happens when it crosses a route between two other bodies?"

No routes in space, B. If you're saying what happens when a spacecraft's trajectory lawfully crosses into a surveillance exclusion zone, obviously the same thing that happens when an air carrier crosses into some country's airspace -- it has to get clearance and proceed according to flight plan.

"Or if an asteroid being mined by power A drifts into Power Bs bubble."

It would be like a truck passing through a foreing country. It would be subject to inspection and confiscation (of contraband items at least, possibly of the whole sateroid).

"Not to mention the chaos in a system with multiple moons."

I woulod think a system of multiple moons would be unified. If it wasn't, well...it's not like we haven't seen international cockpits on Earth.

"Also, given that nations on earth are used to being observed by satellite, why would they suddenly become paranoid about privacy?"

Because drone surveillance against a planet in sovereign control of its own space is technically and legally more like an aerial overflight than a satellite one.

"And it's within the practical capabilities of a number of countries to build enough missiles to sink a carrier. We still have those, don't we. The fact that a vessel can be killed by cheaper weapons does not render it utterly obsolete."

Now this is where space really is different. Bombs keep going once you drop them. The analogy is not to a carriers, but to AA guns or missiles that have to first defend themselves before they can defend anything else, under attack by bombers that don't themselves have to come within shooting range.

Tony said...

Byron:

"It can be oversold. I've never supported the multi-light-second ravening beam of death. That doesn't mean it isn't the optimal design for a standard warship under tech assumptions that are based on such a concept existing. Which is a bit of a stretch, but assuming that space warfare is anything more then nuclear war in space requires it."

Non sequitur, yet again. Space warfare can take any number of aspects using nothing but fairly short ranged lasers, kinetics, bombs, and missiles.

"Is it just me, or did you just describe the battleship under torpedo attack, and the carrier under missile attack? Both are far cheaper then the target, but the target in question still got built."

See my previous post. You're imagining laserstars as battleships fighting destroyers or strike aircraft. I'm seeing them as AA guns fighting bombers that are probably out of range, and left with nothing to do but defend themselves against the incoming projectiles.

"On a more meta level, two swarms of kinetic vessels shooting at each other has no purpose whatsoever. They each fire their munitions and die. Game over."

Another non sequitur. Even numbers could easily find themselves unable of killing each other, thanks ot defense being easier than offense, under most assumptions. So mass, economy of force, security, surprise, etc have an effect.

"Thus, if we are to have space war to discuss, it must include something more. That would be something that resembles a conventional warship. Logic applied to lasers results in the laserstar."

No it doesn't. See above.

"So yes, you gain the crown of ultimate realism. Enjoy it, but remember that most people don't enjoy nihilism in their space warfare."

I guess you've arrogated to yourself the role of Shameless Snarker. That's fine...I was getting tired of it anyway.

Byron said...

Tony:
Who's slowing down? You're just shifting awya from and back to an established interplanetary trajectory over days or weeks. The carrier's drive does all the big time delta-ve maneuvers.
I'm confused by what you mean. Leave the carrier, point at the target, drop kinetics, return? Why use fighters at all? There's no benefit over using a missile.

What are my views on scanning, exactly? I don't think I've ever articulated them -- or you mean something different by scanning than I do.
Irrelevant. Based on your comment, it is significantly larger then the hill sphere, but much lower then what the rest of us would suggest. Under my assumptions and your definition, international space wouldn't exist inside the orbit of Pluto. Under yours, it's just quite large.

No routes in space, B. If you're saying what happens when a spacecraft's trajectory lawfully crosses into a surveillance exclusion zone, obviously the same thing that happens when an air carrier crosses into some country's airspace -- it has to get clearance and proceed according to flight plan.
Yes. Except that instead of staying in one place, countries move around. There is no particular economic benefit from deep space that would justify dividing up so much of it.

It would be like a truck passing through a foreing country. It would be subject to inspection and confiscation (of contraband items at least, possibly of the whole sateroid).
And this strikes you as a good idea why, exactly?

Because drone surveillance against a planet in sovereign control of its own space is technically and legally more like an aerial overflight than a satellite one.
Did you even read the part where I suggested asking them for permission first? If it's someone you're at least nominally friends with, then it might not be a bad thing. They know you're not secretly making Q-ships to attack them, and vice versa.

Now this is where space really is different. Bombs keep going once you drop them. The analogy is not to a carriers, but to AA guns or missiles that have to first defend themselves before they can defend anything else, under attack by bombers that don't themselves have to come within shooting range.
So space is different now, when it's convenient for you? How strange.

Another non sequitur. Even numbers could easily find themselves unable of killing each other, thanks ot defense being easier than offense, under most assumptions. So mass, economy of force, security, surprise, etc have an effect.
Really? If kinetic defense is so effective, then why haven't you raised it as an alternative? Or are you just being contrary.

Tony said...

Byron:

"I'm confused by what you mean. Leave the carrier, point at the target, drop kinetics, return? Why use fighters at all? There's no benefit over using a missile."

Fighters can continue on to missions in the lower orbitals after the laserstars are out of the picture. Or your first wave is unmanned busses, but the your 2-x waves have scout/attack ships on carriers.

"Irrelevant. Based on your comment, it is significantly larger then the hill sphere, but much lower then what the rest of us would suggest. Under my assumptions and your definition, international space wouldn't exist inside the orbit of Pluto. Under yours, it's just quite large."

Pure, unadulterated exageration. We know from practice that you can see stuff up close to planets, using probes and minimally magnified cameras, that Hubble can't see from here orbiting Earth.

Also inconsistent. If your idea of universal scanning at long range is ture, why do you suggest scanning drones positioned close to the target to begin with.

"Yes. Except that instead of staying in one place, countries move around. There is no particular economic benefit from deep space that would justify dividing up so much of it."

Who's deviding it up? We're talking about planets that are sovereign and in sovereign control of their surrounding space. That space stays put around the planet and moves with it. Also, since a planet has, by definition cleared out is own orbit, there's nothing but a few random crossing asteroids to contend with, legally speaking.

"And this strikes you as a good idea why, exactly?"

It's neither good nor bad. It just is. You have an inhabited object passing close enough and slow enough to board and inspect. So you board and inspect, and if the owner is up to no good, he forfeits his rights, just like anybody passing through your territory has always forfeited his rights for skulduggery, throughout history.

"Did you even read the part where I suggested asking them for permission first? If it's someone you're at least nominally friends with, then it might not be a bad thing. They know you're not secretly making Q-ships to attack them, and vice versa."

If it's somebody you're friendly with, it's not an issue. If it isn't then the rules against hostile overflights apply.

"So space is different now, when it's convenient for you? How strange."

Sorry, but you're wrong in your insinuation. The analogy I used is always how I have conceived the laserstar vs kinetics issue. You're trying to have it both ways by having the laserstar behave as a simple defensive system when it suits you, but equate it to a battleship when you want it's economics to seem more like the naval warfare economics of the battleship era.

"Really? If kinetic defense is so effective, then why haven't you raised it as an alternative? Or are you just being contrary."

Different scales and tactical situations are in play. The laserstar as advertised is the optimum kinetic defense. But even the optimum defense is vulnerable to a big enough attack. One would have to expend a lot of concentrated effort to neutralize a laserstar, but once neutralized, it's gone for good (or at least for the duration of the war).

Now smaller ships can't defend themselves as well, but they're also not being overwhelmed by mass attacks. Or, if they are, only at the cost of not overwhelming somewhere else. And some number of ships may not be totally eliminated, even by an effective attack. A few -- or even many -- may proceed on to attack their objectives.

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