This is discussion archived from a time before the current discussion method was installed.
Working Title: Stealth In Space: From YKTTW
Larry D: Second Law of Thermodynamics not unbreakable? Well, someone's going to try.
onyhow: Well, The Other Wiki says that the Demon will actually expend energy, so entropy will still increase, just elsewhere. Entropy can normally decrease locally, like the fridge, but elsewhere it still has to increase, so in average entropy will increase.
Korval: Should cloaking devices be on this list? Stealth is a way to beat detection by not radiating or reflecting something detectable, like modern Stealth fighters. Cloaking is using Applied Phlebotinum (though we're getting close to something like this nowadays with modern technology) to bend light around itself and reduce its radiating emissions to zero (or close enough).
Korval: Removed this:
- They hang a lampshade on this during one of the movies, as Spock and Mc Coy hack the guidance system of a photon torpedo into sniffing out tailpipe emissions. In other words, they improved upon the photorp's design by making it a heat seeking missile.
Star Trek VI clearly stated that it was a gas seeking torpedo. Heat had nothing to do with it.
- Not necessarily. ST VI states plasma-seeking, homing in on the plasma emissions of the propulsion system. As noted in this article, those emissions would most likely be quite hot (certainly more so than the background heat levels of space), and thus these plasma-seeking torpedoes could be considered to use heat as one of the tracking properties.
Bluetooth The Pirate: Those missile decoys aren't really an example, decoys to draw fire are the exact opposite of stealth, they're only useful if the enemy already knows you exist.
I have to disagree with the conclusion here that stealth in space is impractical. As Douglas Adams put it, "Space is big." There's a lot of area on the surface of a sphere of a couple light-seconds, and do you know how small the field of view is on a telescope powerful enough to detect something that far away?<br> The heat issue can also be overcome. Insulate the entire ship, and use a laser to dump the waste energy. As long as you don't aim at something deliberately, the chance of the beam hitting anything that can detect it is infinitesimal.<br> That said, I'll grant that space is also really, really empty, too. Anyone who does know where to look - say, because you fired at them - will find you inescapably. So I suspect that it will turn out that it will turn out that ships in space are utterly undetectable beyond point-blank range until they fire, and then an unmissable beacon out to extreme range untill they can loose you again.
onyhow: Sorry, but that will break thermodynamics. Using laser itself will cause even more waste heat, thus with insulated ship, will cook all the crew alive. If you open a fridge in a closed room, the room will heat up not cool down because energy needed to cool down is even more, and will heat the room up. If you can cool your ship without any more heat, you broke thermodynamics, which means that you allow perpetual motion to happen. Space is big, sure, but since the ambient heat generated by ships is much more noticable compare to the CMB, you don't even need telescope to detect them. And if they use thrusters, as stated in the article, RCS (maneuvering thursters in space shuttle) usage can be detected from 1 AU away. If you want to go fast, you need powerful engine, which means it's even easier to detect.
The Nifty: Stealth in Space is one of those Reality Is Unrealistic things where your intuition seems to say that it'd be easy, but when you examine it closely you see that it can't be done without violating the laws of thermodynamics. It's very easy to detect heat in space, and it's very hard to make a space ship that doesn't give off ludicrous amounts of heat. Right now, with our level of technology, we could create sensors small enough to equip on a spaceship that could detect anything in the solar system that was more than a few degrees warmer than the background temperature. The website linked in the description has the details.
Nornagest: I'm not sure about this. Detecting the visual or IR scatter off a spaceship-sized object is easy from 1 AU — if you know where to look. I haven't done the math, but my engineering sense tells me that it would be intimidatingly difficult to design a passive scanning system that could monitor all angles of approach with a high enough resolution to catch something of that size. Even crunching the numbers would be difficult without a supercomputer to work with — that is a huge amount of pixels to process.
I did read the link — the sky-search bit, which is what matters here, assumes a ludicrously bright torchship design with its engines firing (most SF media uses some kind of reactionless drive with few visual emissions, which doesn't make much sense from a physical standpoint but doesn't have to) and also makes some questionable assumptions regarding image-processing capabilities.
AS Wilson: This all seems way too authoritative, both for the sketchy citations supplied, and for tvtropes in general. It's veering far into TheOtherWiki territory. That website seems to hinge largely on one guy, John Schilling, and one equation. This equation is, of course, never explained. I'm not saying I inherently distrust this, but it seems very sloppy, and in any case I refuse to use any conclusion based on an equation that I can't see a proof for.
Dausuul: I agree with AS Wilson. Yes, it's easy to detect IR emissions in space, and yes, it's hard to avoid emitting IR, but "hard" is not "impossible." All that a stealth ship has to do is find a way to contain its IR emissions long enough to carry out its assigned task. If the ship is very well insulated, and uses a drive that emits only cold particles, then it can be quite stealthy. For a limited time, of course - eventually the interior will heat up to the point that the occupants all fry - but nobody said it had to be able to stay stealthy forever. A submarine, even a modern nuclear sub, can't stay underwater forever, but it can stay down long enough to do what it's gotta do.
I'm modifying the article to be less authoritative, pointing out the difficulty of stealth in space rather than claiming it to be flat-out impossible.
(I do disagree with AS Wilson on one point; this article would never fly on The Other Wiki. It would get taken down immediately for lack of reliable sources.)
With respect, I would like to point out that astronomers are still nowhere near being able to track all asteroids which could potentially threaten Earth, even though such objects are typically heated to ~100 degrees Kelvin (which is way above the temperature of the cosmic background radiation, at approx. 4 degrees Kelvin) and most of them are arguably starship-sized (or indeed larger). IRL it takes a combination of very powerful optics, benedictine patience and no small amount of luck to be able to detect such an object, even in relative proximity to Earth...
nayhem: A lot of Space scenarios assume that two objects are less than a few kilometers apart during an engagement, whether or not the script says otherwise, simply because people have problems with large magnitudes in general. From a more likely distance of—say—a gigameter (Earth to Moon is 384 megameters), most modern manmade objects can barely be found against celestial surroundings. Sensors would then have to be capable of telling apart every little twinkle. Stealth in these situations would be synonymous with having better sensors than your opponent, or at least camouflaging oneself against the brighter spots in the starscape.
- Most manmade objects can operate at next to freezing, manned ships can't, so at some point your heat emissions are going to give you away, probably some time before you're inside your weapons' effective range. Besides, the planet 'always' has the sensor advantage, it can afford to stick up a skyscaper sized detector array that blazes like the day, since its not trying to hide.
Dangemike: OK, Nuked some Natter from the main page: this ain't "hey let's talk all about our favorite fighter planes". Save it for the fora. For those who care, the lengthy speculative discussion was as follows:
- As stealth technology advances and spreads, it is theorized that, unless there is a breakthrough in sensory technology, stealth fighters in the future will have to return to Old-School Dogfighting because stealth technology, along AESA radars which can disable missile sensors, will render long-range guided missiles useless. This was part of the reason that thrust-vectoring nozzles and a 20mm Vulcan cannon were included on the F-22 Raptor, even though its main present-day tactic is to use its stealth and long-ranged AIM-120 AMRAAM missiles to snipe off enemy aircraft with utter impunity - a tactic made possible by the fact that it is, for now, the only stealth fighter in the world which is in service.
- Very unlikely to happen because an aircraft's gun only has a range of about 2km while even the stealthiest aircraft can be detected through a variety of means (like infrared or simply very high power radar) at tens of kilometers. Similarly missiles can be hardened against microwave emissions from AESA radars. Tens of kilometers is still very favorable compared to the the +100km non-stealthy aircraft can be detected and killed at though.
- It's not the same as the real thing, but an F-22 did get a gun kill on an F-16 during a Northern Edge wargame. The F-16's pilot didn't even know what hit him due to the F-22's stealthiness. An RAAF exchange pilot who was flying an F-15 commented that fighting the F-22s was like fighting Demonic Spiders; he couldn't even acquire a lock with missiles even when he could plainly see his target with his own eyes.
- You have to question what's wrong with the targeting system if it can't use visual data when the target is close enough to see that way... It's also worth pointing out that this only applies to targeting systems on board aircraft; more advanced ground-based systems can still target an F22 if they want to show off (the only people who can do this are on the same side as the Americans, usually).
- This is because by its very nature air battle quickly becomes a close range affair. The airplane can't stop moving, and it can't shoot weapons backwards hence to attack it more or less must fly toward the enemy, and if the enemy intends to fight he must do the same. With closing speeds between modern aircraft in a head on approach that easily top mach 3 even miles of distance can be crossed very rapidly. It's not hard to think a similar effect might occur with spacecraft the range would start very long, but the ships can really only fly forward (unless they turn there ass to the enemy and begin a deceleration burn)so they'd likely be hurtling toward each other at extremely high speed likely ending in a close range "drive by". If they kept turning back into each other after these passes to continuing re-engaging they'd likely end up going slower and slower relative to each other and fighting at closer and closer ranges. For this to occur though the ships in question would have to be so strong that weapons being used can't quickly score long range kills.
- Except modern air-to-air missiles can hit targets ahead, behind, beside, above or below an aircraft. It's even easier to do it in space (think turrets). Future aircraft (like the F-35) will combine that ability with complete all-around sensor coverage (so it doesn't need to be pointing at the enemy to see them either). So yeah.
- Stealth isn't actually unbeatable either, not if you have the right sort of equipment.
chochlik: In some particular universes, eg. in Mass Effect, one could use mass effect to generate a hollow spherical shell around ship, which would generate gravity field. Physics say it wouldn't affect the ship itself, because vector sum of all forces would be zero. Every signal trying to get out (eg. heat) and every signal from outside (eg. radar or scanning laser) would bend and/or be absorbed by the shell. Whole object would look like a small black hole. However, it could still be detected if there should be something behind it (and there's a black hole instead), but as it needs special circumstances, it can be said that this is true stealth in space. Drawbacks are that the ship would be more vulnerable to weapons (especially mass drivers), as their energy would rise when closing in.
Unknown Troper: Speaking of Mass Effect, I pulled all the natter around the ME entry. If you want to discuss whether ME's method is feasible, do it here. Incidentally, while I agree that a camera array might render the Normandy's stealth system inoperable, said stealth system is brand new and no one at that point in the setting's history is equipped to deal with it. The idea that the system is "illogical" because there exists a countermeasure for it is silly. History is filled with examples of new warfighting technology being developed and almost immediately there being a countermeasure against it developed by the opposing side. That doesn't stop the tech from being developed and used, it just means that the tech and the people using it have to adapt to the counteasures being used against them. The Normandy's stealth system may be new and effective now, but that doesn't mean it'll stay that way forever. The enemy adapts and develops a countermeasure against the stealth system, and the designers of the stealth system come up with their own improvements to address them in turn, e.g. light refracting technology like what we're developing nowadays. (in fact, use of an Invisibility Cloak in conjunction with the Normandy's emmission-catching technology would work really well....) That's the arms race.
