Comments on Rocketpunk Manifesto: Space Warfare II - Stealth Reconsidered

I wonder how easy it would actually separate an IR...

2012-02-06T09:08:41.593-08:00

I wonder how easy it would actually separate an IR decoy "lamp" drone from an actual warship. I've heard the usual argument about emission lines, but that usually involves doing spectrography on it, something that takes hours in real life to get the proper exposure.

A smart enemy would do engine burns only for a couple of minutes at a time, and you'd never be the wiser. You'd have very little ability to tell whether those interesting pixels of IR that your telescopes picked up are attacking spaceships or decoy emitter drones.

I think Daniel's objections have not really be...

2012-02-05T12:19:56.876-08:00

I think Daniel's objections have not really been adequately adressed in the discussion. The distance at which something can be detected is rather meaningless - unless you have reason to expect that anything moving in the area is a potential threat. Given the delay in measurement on interplanetary distances, you might not even note a divergence from known "traffic lanes", if such exist at all, until it's already too late. A telescope network is a nice idea, but in reality introduces further delays, because the information has to go from the source to the telescope first, and then from the telescope to the defender, which is a larger distance than straight from the source to the defender.

I think the discussion has been too focused on the basic detectability. But stealth is not about the "invisible ships" someone mentione. When an F-117 flies by on a bright day, you can easily see it. When you stand next to its landing strip, you can see it at night. Stealth is not a Klingon cloaking device, which is what the arguments presented really rule out. Stealth is making it hard to identify you as what you are and making it harder to target you. In the end, that is perfectly possible in space. Will there always be a way to detect a ship? Sure. Will there be a way to identify a ship as a threat and target it and take it out IN TIME? Much more difficult. Especially when you're an unsuspecting target either as a sitting duck (by space standards) or travelling on a consistent vector.

As RPGs were mentioned, I loved how the space combat system to a previous edition of SpaceMaster really reduced space battles to fighting with maneuvering thrusters on a scale of a few dozen km. Kick your main engine online and you're out of the battle.

I've been reading about the stealth in space i...

2011-09-05T05:58:35.090-07:00

I've been reading about the stealth in space issue since I discovered it a few days ago and there a few things that seem incorrect to me.

First, the equation for determining distance that a ship can be detected applies to surface temperature, but people frequently use it to apply to cabin temperature.
With enough insulation you keep the outer hull as cold as you like without cooling the cabin. What's important is the amount of heat being generated in the ship. Heat in = heat out.

Second, the detection range of an engine burn. The calculation for this seems to assume that all waste heat is radiated, but most of it is in the exhaust. As the exhaust is ejected into a vacuum, its pressure will drop rapidly, which will also cause the temperature to drop. Since radiated heat is T to the power of 4, only a small fraction of the heat in the exhaust will be radiated.

Or am I missing something here?

Gareth.

Welcome to the comment threads! 'Everyone bli...

2011-05-25T12:59:11.236-07:00

Welcome to the comment threads!

'Everyone blinds everyone' does raise some interesting tactical conundrums! I will probably deal more with some of these issues in upcoming posts.

I've been reading through the various posts on...

2011-05-25T05:54:41.476-07:00

I've been reading through the various posts on space warfare degenerating into the proverbial "eyeball burning" contest. Remember destroying an opponents sensors is a mission kill.

Stealth may be possible because useing a passive sensor is to risk being blinded.

It strikes me long range IR sensors will be extremelely vulnerable to "blinding lasers" and will be disabled long before effective weapon ranges are reached.

In fact any passive sensor mounted on a ship/guided missle/drone could be easily disabled by blinding lasers.

Likewise, your really really expensive multi-meter laser can be disabled by a much cheaper and smaller blinding laser.

If you were postulating a an exciting setting for space warfare plentiful cheap and nasty blinding lasers may mean the whole battle degenerates into a relatively close-in-battle relying on active sensors (read radar) with unguided kinetics and high thrust spacecraft.

Basically some sort of fighter that is relatively stealthy to radar!

Disabling an opponents sensors is a mission kill afterall and there is no need to physically tear the opposing ship apart if it is blind.

I'm bookmarking all these classic threads.

2010-10-05T06:02:13.439-07:00

I'm bookmarking all these classic threads.

Rick, I think I see part of the disconnect for th...

2010-08-24T06:59:08.022-07:00

Rick,

I think I see part of the disconnect for this discussion. The Atomic Rockets page provides equations and numbers for the *maximum* possible detection ranges.

It seems that many here assume that this number will be the *actual* detection range. They also assume they'll get Hubble type precision imaging from a sensor with a field of view 10deg x 10deg AND that their sensor suite will enable viewing of all frequencies from IR through gamma range.

Effectively giving them the abilities of Hubble, Compton, Spitzer, and Chandra telescopes as far as resolution and precision AND also over a large section of the sky.

But that's not how these things work. You get resolution OR field of view, not both. If you want to cover the spectrum of all four of the mentioned telescopes, then you need to carry their weight/size in sensor equipment.

That's quite a hefty payload for a 100 m warship (though not for a 1 km sized one).

Spreading your sensors out to drones/support ships helps a bit but ultimately you'll need "light" collection and that requires a lot of collection area. Small 'scopes on secondary craft will not be as effective as a large 'scope on the primary.

IOW, I think that the assumption that everyone gets to see everything (especially in the 1 on 1 scenario) is doubtful. It assumes that there are no required engineering trade-offs between sensor power and size or sensor resolution and field of view. IMO both of these are "bad" assumptions.

In the other case (long existing players in a known system) the requirement to look everywhere at once significantly declines and the need for full-sky surveys every 4 hours dramatically relaxes.

On the laser thread they mentioned 4 zones (can't see, can see with passive sensors, illuminate with active sensors, and weapons range). As an engineer I would think very carefully about those 4 zones and how to best prepare any craft for potential trouble while making trades between the different constraints. If your tech level didn't include drives capable of producing gamma rays, I'd leave off the gamma ray detectors.

This would almost certainly mean that a ship "running silent" could slip within 1,000,000 km to perhaps 500,000 km.

Also remember the drive detection ranges listed were also the *maximum* possible detection ranges. If you had only had Hubble type (high angular resolution, small field of view) optical/near IR detection and were not looking in that direction during their burn, then you wouldn't see a thing!

Of course this plays right back into your discussion of the difference between stealth and tricky. Being tricky and running silent could confer the equivalent of stealth. Meaning a warship *could* spot you if they knew where to look. It's sort of like a magician's gag, don't be too obvious (high-g burn) and a little misdirection ("hey, look over there") could provide the tactical equivalent of "stealth".

At some point though, even a ship "running silent" is going to pass close enough to tip off the large field of view sensor suite and then you get to discover just how good your misdirection works ("we're only a cargo ship carrying volatiles to Ceres.")

Jim

Oops. The brilliant exception is nukes, which full...

2010-08-23T20:44:13.195-07:00

Oops. The brilliant exception is nukes, which fully lived up to expectations.

Detection will be more difficult in an unfamiliar ...

2010-08-23T19:40:03.832-07:00

Detection will be more difficult in an unfamiliar star system, where vast numbers of natural bodies need to be tracked and cataloged. A 'coasting' ship could be difficult to detect among this clutter.

A ship lighting up a high power drive is another matter, because these are VERY bright, and have a distinct spectrum.

But ordinary civil ships in familiar space probably keep no scan watch to speak of, depending on some traffic control service. Ships intended for travel to unfamiliar space will usually have decent scan suites, and will take scan more seriously.

Military ships range from comparable to civil 'adventure' ships, on up to battlecruiser grade scan suites intended to carry out a fast, thorough survey of a system.

Rick said: >>With one extremely conspicuous...

2010-08-23T14:01:02.374-07:00

Rick said:

>>With one extremely conspicuous exception.

Ok, I'm dying to know. What's the one extremely conspicuous exception?

Ah, I see part of my disconnect with the conventio...

2010-08-23T13:08:13.625-07:00

Ah, I see part of my disconnect with the conventional wisdom.

Case 1) Future Sol system interplanetary warfare.
All participants are familiar with each other and the solar system. They know what's supposed to be there and what's not. Each side has numerous sensor platforms (scientific, military, trade, etc.). Anytime ANYTHING new or unexpected is found, it gets quite a lot of sensor time devoted to it.

Case 2) Sensing ship is solitary sensing platform AND unfamiliar with the "terrain".
This can come about if an interstellar ship arrives in the Sol system OR if one of ours goes there OR if two survey ships meet in a newly discovered system.

In the first case, odds of detection and discover are quite high.

In the second, it may take quite a long time for one side to figure out where to look. Upon finding "something" it may take another long time to determine that "something" is a hostile ship. It'll take NASA 10 years and MANY sensing platforms to discover 90% of NEOs down to 1 km!

Some additional reading:
http://en.wikipedia.org/wiki/Near-Earth_object#Close_approaches

http://en.wikipedia.org/wiki/Spaceguard#History

On one page I saw an estimate that a 100 m ship at room temperature (say 300K) could be detected at 38,000,000 km. Yet the NEO close approaches show much worse detection ranges!

Consider the last 2 moons of Jupiter found and the last 5 NEO approaches and I get an average *detection* range for a 100 M sphere at 300K as 625,000 km (with a Std Dev of about 1,250,000 km). Even worse I have no means of incorporating the objects we DIDN'T even see.

"The difference between theory and practice is larger in practice than it is in theory."

I think this means my previous suggestion is a good one. At best a detector can detect some % of objects. That % goes up asymptotically as the power emissions go up and as an inverse asymptote to the range. Those slopes can be quite steep but you're never going to be 100% mathematically certain (even though you can be pretty certain if your detection crosses some real life threshold - 99.99%, 3 signma, etc?).

One factor here is just plain money. If we were wi...

2010-08-22T18:01:08.758-07:00

One factor here is just plain money. If we were willing to spend as much on detecting Earth-crossing asteroids as the US spends on AEGIS cruisers, we would detect a lot more of them.

This does potentially go both ways - in classic operatic scenarios, a patrol corvette in some remote corner of the galaxy is not going to carry a battlecruiser grade scan suite.

In Solar System scenarios you have to assume that all major players will have access to first class equipment. That is what makes them major players.

Having said all that, there is a meta issue here. One phenomenon that astronomers have never dealt with is the fog of war, and how weapons and other systems perform on the battlefield is hardly ever like their performance on the bench, let alone on the back of an envelope.

With one extremely conspicuous exception.

Also another comment on detecting drives... As I ...

2010-08-22T14:35:09.012-07:00

Also another comment on detecting drives...

As I mentioned earlier a collimated drive would be difficult to detect outside of a small arc directly behind the ship. The ultimate in collimation would be that of a mass driver.

Oh sure, if you were directly observing a vessel and saw acceleration it wouldn't be tough to figure out what you were seeing, but consider a ship "hiding" but running on minimal power. It could maneuver some but I would think that there's not much delta V in mass driver propulsion system.

Still that 10% uncertainty of not seeing a ship "hiding" and that the ship could still maneuver could be a BAD combination.

All of these advantages decline if the hiding ship moves out from the "clutter" though (away from planets, moons, asteroids, the disk of the sun, etc.).

And no amount of LO technologies is going to keep an Orion project class ship from being detected while under acceleration :)

I wonder, how detectable will a mag sail be? The shear surface area of a solar sail will make it a non-starter for hiding.

One final comment is what about the cooling requirements for IR detectors as well as a host of other engineering problems? Long wavelength IR imposes substantial refrigeration problems on the detection equipment (cryogenic - in fact some require LHe!) to keep the IR "noise" in the equipment from swamping the signal in the sensors. Also what about Cosmic ray interaction with the detectors. These also generate substantial noise in most detectors (though I suppose sufficient CPU filtering ought to remove the worst effects).

I'm left with the impression that the discussion on sensor theory here has left out the reality of what NASA faces in doing a asteroid and comet surveys. Some of these objects are HUGE, with high albedo, and reflecting significant amounts of light. If things are so easy to see in space, completing these surveys should be a piece of cake, and yet they are not.

Just a follow-up: >>If the Oscar's crew...

2010-08-22T14:14:18.668-07:00

Just a follow-up:

>>If the Oscar's crew was shivering at the freezing point, the maximum detection range of the frigid submarine would be 13.4 * sqrt(1510) * 2732 = 38,800,000 kilometers, about one hundred times the distance between the Earth and the Moon, or about 129 light-seconds.<<

I'm STILL not buying this. I don't doubt that the math and theory are correct, but if what this says is true, then our current space program should have no problem detecting ALL Earth crossing asteroids larger than 100m in less than 4 hours (the time claimed in many sections).

A 100m Earth crossing asteroid would be larger than many space ships, should have an average surface temperature about that of room temperature, and should be visible against the back drop of the 3K CBR.

What actually happens is something like a 1/2 life. We detected some right away, but over time we continue to detect new Earth crossing asteroids.

And this is with a LOT more equipment and computational power than will be available to a single spacecraft. It seems to me that every assumption has been made in favor of the seeking ship and to the disadvantage of the hiding ship.

I agree that if one side has multiple sensor platforms distributed throughout the solar system all looking in the right spot, they will always detect a ship trying to hide. But I don't agree that one side will always have multiple sensors deployed, or that they'll be looking in the right direct and at the right time.

Also consider that a ship in Earth Orbit will be difficult to detect with the Earth as its backdrop (especially in IR). Of course this orientation changes as it orbits and it will present the best chance of detection when it's furthest to the side of the planet. Consider that astronomers are still not certain there are no bodies in our solar system between the orbit of Mercury and the Sun even though a large region which could support a stable orbit exists. This is a region 60,000,000 miles in diameter!

At best when writing such a novel, the protagonists might be able to declare, "our Monte Carlo simulators indicate that we've detected ~95% of all space craft down to 100m in the region." or some such. While good in theory, the missing 10% in combat could be quite lethal.

Chase, Keep up the good work and posting your com...

2010-08-21T15:56:48.400-07:00

Chase,

Keep up the good work and posting your comments. I understand and agree with the base argument, but as with your thoughts, there's a lot of "noise" to consider.

At a far enough distance a "burn" signature may not be distinguishable from a star for certain burn temperatures and without multiple detections to work out parallax or trajectory.

Furthermore if a burn was conducted out of view (or when the observing ship was looking elsewhere) the approaching ship in ballistic trajectory will be significantly more difficult to spot. After all how much energy does a craft emitting just life-support and waste heat from the computer and power systems generate? Surely many orders of magnitude than that generated by the craft's engines (for any self-respecting SF story ;) ).

Another aspect to all of this is just how much of the torch ship's "plume" is visible to a ship not looking straight up it's tail pipe? A very efficient drive such as photonic or plasma based with a high level of collimation would not through much signal in other directions.

Some "nozzle" designs would direct the exhaust mechanically (i.e. SSME) while others (such as many fusion variants might do so electromagnetically (e.g. fusion and fission fragment type engines).

I would think that electromagnetically directed plumes might have open structures that allowed more visibility to the released gamma rays, etc. but would radiate MUCH less IR (making a case for a multi-frequency sensor suite).

Also all of the arguments I've seen mostly consider *thermalized* exhausts and don't discuss those not in thermal equilibrium (such as fission or fusion fragment engines). This also argues in favor of a multi-frequency sensor suite (keep an eye out for those gamma rays!).

The only problem with the theory that resolution w...

2010-03-19T12:04:46.075-07:00

The only problem with the theory that resolution would have to be very high is that we're not dealing with trying to find a black object on a white background. We're trying to find a light in a dark room.
For example, Epsilon Eridani has an apparent visual angle of 9.711e-11 degrees (if I did the math right), which is a lot less than the minimum human perception, which is about 1.2 arc minutes according to wikipedia. You can't treat the ship as a non-radiating object.

Alright, so I've spent more time with the math...

2010-03-08T12:01:31.927-08:00

Alright, so I've spent more time with the math. Back-of-the-envelope calculations for a 30x30mm longwave photodetector system at 16MP density (~4k x 4k pixels) requires a 3.6 degree FOV to detect our hypothetical 50m ship, at the upper edge of LEO from the lower edge of LEO, as a single pixel. Anything wider FOV, or wider separation (like, for example, when they don't share a terrestrial radius), and the vehicle we're attempting to detect will subtend less sensor area than a single photosite. This has lots of problems for the notion of being able to "spot" another spacecraft which is in an arbitrary orbit. Your SNR looking into the light of any local body is going to be 0dB.

According the Wikipedia article on thermal imaging the resolution of modern longwave detectors is limited to about 320x240 pixels. That's an order of magnitude less resolution than I'm stipulating, and that plausible futuristic system still requires dozens of cameras to implement.

An alternative to complete coverage I've come upon at the Atomic Rocket page about stealth in space is that of slow scan detection. At one point it is determined that a full sky scan can be completed in 4 hours. To which I must ask: a full sky scan of what? in LEO your orbital period does not exceed 2 hours, 10 minutes, and at the lower end is near 90 minutes. How does any ship in LEO have any guarantee of detecting another ship in LEO when it takes longer to scan the sky than the orbital period of either? How do you expect to get any kind of useful information about a passive emitter when it takes you 4 hours to get a single still image of the vehicle?

Note that the slow-scan analysis was also targeting a vehicle engaged in a burn.

I'm still not entirely convinced that the "stealth in space" thesis is wrong, I need to work out the numbers in more detail, and look at more of the Atomic Rocket arguments, but its seriously starting to look untenable from a technical standpoint.

I've been playing with the math a bit, and I w...

2010-03-08T09:45:55.162-08:00

I've been playing with the math a bit, and I want to point out a couple of specific areas of technical issues that are being overlooked. This isn't to say that these technical areas rule out the "no hiding in space" issue, but that before it can even be determined if you can hide in space, these technical questions need to be answered.

First: I'm assuming right now that the only thing you get is passive IR emissions. Drive flares can be timed to coincide with periods when you're invisible to the observer, so I don't think any paranoid patrol boat captain is going to rely solely on drive flare visibility for his intel gathering.

So, quick googling shows that passive IR is going to be in the longwave range, 8-15µm. Given plausible detection technology at that wavelength range, what optical focal length is required for a 50m craft that is 1840km away (the maximum separation attainable while everyone is in what is considered LEO) to be resolved to greater than the size of a detector pixel? What field of view does this imply? Two degrees of FOV is going to be a bitch, when you have to cover 360 degrees of view, in two dimensions. If you can get away with a lens that's got 180 degrees of FOV, on the other hand, not bad, only needing 4 cameras at a minimum.

How about Signal/Noise? What's the optical SNR of a 50m IR radiator at 1840km against a background of stars? Near or over the solar disc? Near or over the lunar disc? Near or over the terrestrial disc? If it's not possible to distinguish a 50m radiator from noise when it's between you and the Earth, then LEO just turned into stealth mode, although with the ironic tradeoff that in very low LEO, you need more maintenance burns to maintain an orbit.

Related to the above: angular resolution isn't the only thing you need to pick out a radiator a couple of megameters away from you on IR band, you also need enough photon gathering power for it to show up on the exposure you can get. The exposure you can get is going to depend on your relative velocities, the aperture of your lenses, and the frame rate you're capturing with. It's quite possible that a ship is quite a bit brighter than the background, but that you can't see it anyway, because your exposure is too dim.

So these are some technical issues regarding passive detection of IR radiators in orbit. If you know of some place that answers these technical questions, I'd be much obliged. If not, I'm working through the problem myself, and eventually I hope to have a better idea of the plausible technical detection capabilities of spacecraft. Can you see, though, why I think these high level discussions of stealth/detection in space don't really answer the question one way or the other? It is possible in principle to detect anything out there and calculate everything about its kinematics, but "in principle" isn't the same as knowing a solution can be engineered to do that.

Thanks for the welcome :) I'm trying to look ...

2010-03-08T08:59:27.212-08:00

Thanks for the welcome :)

I'm trying to look at this issue not from the perspective of someone trying to hide, but from the perspective of someone trying to keep watch, or an engineer trying to design a space vehicle with the best scanning abilities that are currently plausible. I think there's a big difference between "You there, trying to hide in orbit, will almost certainly be spotted by someone" and "I need to reliably spot potential aggressors at the maximum possible range and with the most information I can possibly extract using modern sensors. How do I do it, and more importantly, how often will I fail?"

So I'm looking at this from the perspective of a sensor suite engineer, trying to figure out the real values involved. I think you're partly right, in that intentionally hiding is going to be hard. But I think the perspective that seems to dominate in discussions of stealth/sensors in space is a bit misleading, the "you can't hide" perspective. I prefer the "can I always see bad guys" perspective, because in the long run, sometimes failing to spot the bad guy can be very, very lethal. I don't buy that "you can't hide in space" implies "I can always see the bad guy".

Accuracy and precision in tracking are also very important. It's not enough to say that you can't hide movement in space. If you're trying to engage in boarding maneuvers, or combat maneuvers, you must know the others orbit to an extremely precise degree, and I am cautious of simply assuming that the stipulated capability of noticing a drive flare implies the ability to calculate the velocity and orbit of a ship to the necessary degree of precision. To some degree of precision surely, but "some" degree of precision doesn't make a targeting solution.

It sounds like the discussion here tends to prefer more abstract or social forms of obscurity, which are easier to discuss without reference to mathematics and engineering. These are important points, but I think the difficulty of doing the math has caused an interesting discussion to fall by the wayside in favor of simply assuming that, if you're in space, you're being tracked by anyone on your side of the planet to an arbitrary degree of precision. In practice, the degree of precision that different sensor suites give for different kinds of information will heavily inform combat and police operations, unless it turns out that sensor systems are so useful in space that literally anyone can track literally anything to an arbitrary degree of precision. I highly doubt that is the case.

Welcome to the comment boards! The key point her...

2010-03-05T19:04:20.413-08:00

Welcome to the comment boards!

The key point here may be your last one: hiding from whom? First a couple of minor responses.

Range information can come from parallax - you don't need a huge baseline, though big scan platforms may deploy some free flying scopes.

Actually tracking a ship and determining its acceleration is a matter of orbital mechanics. If it is moving in a nonballistic way you can calculate its acceleration (and which way it is accelerating). Then measure the drive flare to estimate drive power, and drive power and acceleration give you approximate mass.

A million important technical details aside,sSo far as I can tell, it is very hard to hide from major military grade scan capability, the spacegoing equivalent of an Aegis cruiser. Hiding from a civil ship that just has basic commercial gear - and may not make proper use of that - may be quite another matter.

But I think the biggest factor will be 'terrain,' not only the physical terrain of planets, but the clutter of spacecraft in orbital space. Warcraft may not be obviously different in appearance, from a distance, or in behavior until they take warlike action.

One form of stealth is strolling along like you are minding your own peaceable business, instead of skulking around.

I've read a fair amount of the "no one ca...

2010-03-05T15:48:38.663-08:00

I've read a fair amount of the "no one can hide in space" argument, and I don't buy it.

Drive flares are visible from a long way away, and everyone is radiating ~300K just to keep the place survivable to humanoids. Occultation is unavoidable.

However, past this, it seems that the practical considerations which actually determine the stealth situation are completely ignored. What kind of sensors are you using? How many, and how are they placed, and if they're optical or IR, what kind of optics do they use? Do you have a few fixed sensors with enough field of view to cover everything around your vehicle? Do those provide enough resolution at the relevant distances to get you solid data?

How do you determine ranging? There are several ways, but all of them are going to require a significant image size (and image size is exactly what you sacrifice with a wide FOV). Sure, you can see a drive flare from halfway across the solar system, but unless you know what the dimensions of that flare are supposed to be, you can't determine orientation to any precision. If you can't determine orientation, there is very little about their orbit you can determine.

Even if you can determine their orientation, is your platform stable enough and your imaging system high resolution enough to determine which direction the craft is moving? The same orientation of the flare could give either an acceleration, or a retrograde deceleration.

Now, I concede the possibility that modern imaging and automated analysis techniques are good enough to make space impossible to hide in. I just haven't seen the evidence that this is the case. Seeing a drive flare in the distance, and even figuring out exactly how much power they're making, doesn't do you much good if they're a spec. And if you have to have dozens of telephoto zoom lenses plastered all over your ship to get the data needed for your scenarios, that'll be a financial barrier to entry. Maybe you can't hide from the CIA black ops ship, but you sure can hide from a cargo carrier you want to sneak up on.

In the outer system, the problem becomes not so mu...

2010-01-01T10:54:12.180-08:00

In the outer system, the problem becomes not so much about sunlight as the need to keep the crew compartment at room temperature, and that heat will leak out. This will rule out keeping a (manned) ship chilled for any extended period.

Alas, I can't really see any way to get 'privacy' in the inner system, short of losing yourself in a crowd of other traffic on the same orbit.

That potentially creates some interesting possibil...

2009-12-29T15:52:34.925-08:00

That potentially creates some interesting possibilities for settings. Barring a “cloaking device” (though the UK/US militaries seem to be making progress there I might sadly add- I’ve never liked the “trek” cloak concept to be honest, too much cheating) hoping you’re not too bright to be seen or that you’ve got some phenomenal heat sinks seems to be the only options (barring that nifty spring fired weapon idea). Anyway, the setting:

1. The inner planets are the peaceful areas (the "inner core") as sunlight is so intense that stealthed systems are impossible to maintain (if internal storage systems become even vaguely possible through superior heat sinks). Combat, if ever, is done thorough drones and planetary silo based missiles, due to the total lack of reasons for strategic manoeuvring. The "outer rim" as it were is perhaps more friendly to raiders and manoeuvring forces, and thus is slightly more conducive to scouts with radar and telescopes sent out to pick up the occasional "heat-dump" and drive flare. The only possibility for manoeuvring in the inner core is within the shadow of a planet- probably impossibly from your target anyway.
2. If a black ship absorbs huge amounts of sunlight, and more is radiated off- then some could be creamed off as power. While solar panels are probably more efficient, I kinda like the idea of black ships creaming off some heat, and using it to superheat water, produce steam and power electrical turbines which goes to life support, ion engines, etc and use some of the remaining heat to simply warm up the interior- essentially a "steam-powered" spacecraft. A setting could consist of the inner planets using these for transportation and the outer worlds using more conventional vehicles.

Of course, if heat sinks powerful enough to absorb sunlight just outside 1AU were developed, then that would immeasurably help me develop one setting I was thinking about (the space between Earth and Mars would feature prominently), and I’m pondering whether Jupiter’s space might be enough (around 300 W/m2 there).
I don’t even want stealth per se to be honest. I’d call it more privacy. A ship can get from point A to B without being watched all the time, apart from the occasional main burn, heat dump or thrusters burn. The idea that everything everywhere can be seen from anywhere has taken me a long time to get my mind around. I rather hope we won’t get to the point where any mode of transportation (or any person!) could be seen anywhere on the planet either.
One last “stealth” thought- liquid hydrogen thrusters to change course (slightly) without anyone seeing you? Or some other medium cooled pre-voyage to 3 Kelvin (and somehow squeezed out of a nozzle manually- extreme pressure?).

Ok, one last one: I read a thriller sometime ago that talked of a (probably fictional) Soviet program to put missiles on concrete rafts near to strategic assets that were NATO aligned. Hearing about the Japanese concept of a solar station to literally “beam power” to a terrestrial receiver, I had the idea of weapons platforms somehow placed near important potential threats, with no power source. That would be right next to your terrestrial headquarters- everyone knows its there but that doesn’t change the fact that the platforms themselves are the temperature of space and radiating no heat. When you want to activate them, beam the power to them, warm them up and give them instructions. Before your foe can react. Now give them the spring fired “torpedo”. Not only does the foe have to find the platforms, he now has to find the ordinance coming towards him. Nasty.

Please feel free to shoots these concepts down gentlemen, I have my parachute ready!

Welcome to the comment threads! One proviso about...

2009-12-28T18:06:25.086-08:00

Welcome to the comment threads!

One proviso about identifying drive signatures - that's an 'optional' feature, so to speak, plausible but not inevitable. Scan might only be able to report the general characteristics of the drive, such as estimated power output. It all depends on fine details of drive technology (and what you want in a setting).

The biggest problem for heat sinks is sunlight, assuming you're anywhere near 1 AU. If your hull reflects it, that's not very stealthy. If you paint your ship black to absorb it, that's a constant 1400 watts/m2 your hull is absorbing, and it will overwhelm any heat sink pretty quickly.

But a couple of people have pointed out that heat sinks might work well for small kinetics that only need to stay cold for a short time. Chill the kinetic and give it a gentle kick out the hatch, and it will be very hard to detect till it warms up.

Having read the earlier posts about hiding in traf...

2009-12-27T16:40:58.827-08:00

Having read the earlier posts about hiding in traffic, I remembered Atomic rocket's thoughts about how drives can be instantly identified down to the class of ship/spacecraft in view. Added to the fact that the entire solar system can see you thanks to infrared (light speed lag not withstanding), thus any power with a supercomputer handy can see you. Now add to the fact that they would have the class of every spacecraft on a database somewhere, thanks to HUMINT, and factor in the processing power of the computer. Thus hiding in traffic means they wiz up a list of the classes of ship in the cloud of traffic you’re hiding in and simply get the computer to go over the list until they find you. Of course, it helps they know what you're flying, but it seems to me that hiding there simply means they have afew extra seconds before they find you instead of doing it instantly in open space. Not to mention the fact that they know your speed and trajectory and will have calculated precisely where you are in the traffic long before you have hidden in it.

P.S: A rather stupid question: these “spherical stealth ships”- were they intended to run on maximum power with the heat sinks (explaining thus why it would not work?) or would the sheer power outage of life support and computers powered on standby have done it anyway, thus rendering the heat sink impractical? I’d like to read up on this more, but Atomic Rockets and others sites dedicated to showing why stealth does not work don’t touch on heat sinks at all.