Superconductors, Stealth vs. ECM/ECCM in Space

[McC]

These (unrelated) questions assume a hard science fiction setting.

• What impact, if any, would superconductors have on the amount of energy one could recover from a fission or fusion reactor operating a conventional steam turbine, as discussed here? Would superconductors increase the amount of recoverable energy in any significant fashion?
• It's a given that there is no stealth in space. If you radiate, you are visible. Period. Does this extend to ECM? I'm not suggesting that you can render your craft undetectable, but would it be possible to sufficiently disrupt self-guided weapons so as to render them ineffective? If someone lobs missiles at you, can you "jam" them so that they fail to intercept you / fail to arm before impact / etc.? Or would the No Stealth in Space rule preclude "jamming" of missile weapons?

[Darth Wong]

On question 1: recoverable energy is a function of Carnot cycle thermodynamic efficiency, which is in turn a function of the working fluid's high and low temperatures. Superconducting materials in the system would make the engineering simpler, but they would not allow you to get around this basic limitation.

On question 2: there's stealth in space, it's just not complete. You can reduce emissions by reducing power consumption, for example. One of the travesties of Star Trek and related sci-fi is that so few of its writers seem to remember that you can coast forever in space. You could have a large floating thermal shield between you and the target, coasting alongside you to block your emissions. You can take advantage of noisy areas such as planets and stars. As far as ECM goes, there's no reason why decoy devices would be less effective in space than they are in atmosphere.

[Junghalli]

The problem with trying to blind enemy sensors is you're still pumping out energy that can be traced back to its radiant source (you). You're not going to be able to convince the enemy missile you're somewhere you aren't, not if it's programmed competently, because no matter which way you're looking at it you're sillhoutted against a basically unchanging featureless background. You could try completely burning out the enemy's sensors with lasers though.

Edit: the problem with decoys is if you're accelerating they aren't going to be very effective unless they have the same mass as your ship, because your engine's thrust is relatively easily calculated from your acceleration and the properties of your exhaust plume. And if the decoy is going to be the same mass as your ship, with the same engines, it seems like you might as well mount weapons on them and make them actual ships.

[Darth Wong]

The problem with trying to blind enemy sensors is you're still pumping out energy that can be traced back to its radiant source (you). You're not going to be able to convince the enemy missile you're somewhere you aren't, not if it's programmed competently, because no matter which way you're looking at it you're sillhoutted against a basically unchanging featureless background. You could try completely burning out the enemy's sensors with lasers though.

You're assuming the radiant source is in fact you. Why couldn't it be some kind of drone you release from your ship?

[Junghalli]

You're assuming the radiant source is in fact you. Why couldn't it be some kind of drone you release from your ship?

That's true, I didn't think of that possibility. I suppose that could work.

[Admiral Valdemar]

You're assuming the radiant source is in fact you. Why couldn't it be some kind of drone you release from your ship?

I've often argued for this as well. You have a ship that utilises drones with either a very large signature to act as decoys, or as stealthy sensor suites with active and passive detectors. Use a LOS laser for comms. and you've got a fairly secure system in place that can be effective for several lightseconds if need be. There are some issues though, namely these decoys won't last long as mass can never be properly replicated without having a decoy that is a copy of your ship, and any floating debris or shield to cover your ship is still going to be readily noticeable and set off alarm bells to wary vessels in the area.

The only true stealth in space would be to go silent running and have a drive system that emits fast decaying particles or is simply shut off, and a way of destroying heat, which without some loophole being found in thermodynamics or way of shunting thermal energy outside of the universe, is not happening any time soon. Meta-materials could help for radar, ladar and visible spectrums, but passive detection of IR is what will nail you every time.

[Mr Bean]

What about the John "Blackjack" Geary series in which ships main detection suits at long ranges is light. Warships in that series and most civilians ships have a series of powerful telescopes aboard hooked up to very good automatic image recognition software.

IE you look 360 around you in the system with the telescope being used to take a few hundred thousand pictures. Then the software runs over the pictures automatically noting the rough position of all know stars, know planets and orbitals. And comparing the visual outlines against a database of know ship types and anomalies. After it removes the anomalies and established objects(The know suns and orbitals in system) it presents what's left along with any matches to human techs and helper AI who further refine the data and then turn that into accurate visible light only detections.

If you have a giant thermal side between you and the enemy it's not going to work as your shield covers up stars that "should be" visible from the enemy ship. Thus the author's logic goes. Even if you have a ship with zero emissions unless you also have some kind of screen to display the stars you will be crossing which in the computers mind will cause know stars to "vanish" as your ship passes between the light of that star and their ship.

And of course such a shield could not be perfect even for a zero emission ship because it would either have to be 360(And thus quickly take damage from micro meteors and become not useful. Or only 180(or 270) and thus not perfect form all angles which meant sooner or later you would be "seen" around the shield.

[Admiral Valdemar]

That would be the other method you could use other than detecting a heat source. Any occlusion of starlight would automatically make you visible to any decently equipped spacecraft, so either you make the shield irregular and natural, like an asteroid or comet, or you simply shoot first. I'd expect such decoys would be regarded as possible threats and have a bead on them up until they get within effective weapons range. Short of spamming a whole sector of space with such decoys, you'd not have the element of surprise, rendering the objective moot.

Stealth would be better found in eliminating the delicate sensors of any enemy ship. You don't need to vape a whole vessel to win, simply take out the optical and other EM band detectors, leaving only mass or shielded passive/active sensors alone, which can still be blinded once they get put to use. Before they do that, you could take out any radiator fins etc. and give the crew far bigger problems.

[Mr Bean]

That would be the other method you could use other than detecting a heat source. Any occlusion of starlight would automatically make you visible to any decently equipped spacecraft, so either you make the shield irregular and natural, like an asteroid or comet, or you simply shoot first. I'd expect such decoys would be regarded as possible threats and have a bead on them up until they get within effective weapons range. Short of spamming a whole sector of space with such decoys, you'd not have the element of surprise, rendering the objective moot.

The problem with pretending to be a rock or iceball is the fact that they don't change course quickly(Or at all). And if you know the system you can simply detect it by comparing it to the know list of objects in that space. Since that could be a quick glaring warning that somethings up when nothing of that size and that speed is in this solar system. Assume hostile.

Also, if the ship has any kind of AI, a Metor or Comet changing direction or speed would be a giant red flag to send along to the bridge crew.

[Stark]

Starfield tracking is as old as the hills (simple star occulsion is even easier for a machine). The idea you need AI to inform crew that an object is in powered flight is hilarious. A perl script would do the same thing.

[Mr Bean]

Starfield tracking is as old as the hills (simple star occulsion is even easier for a machine). The idea you need AI to inform crew that an object is in powered flight is hilarious. A perl script would do the same thing.

So we can whip this up on an Laptop in ten minutes right before the end of the movie?
Your average Star System has hundreds of thousands of rocks flying around it, plus planets, plus comets. From pebble to dwarf planet size. And you can instantly sort through that with a simple Perl script? Again I said this detection system was Visible Light. You can't use Radar because that takes twice as long to return. Once to go there and once to go back. When your talking Star Systems that can be days between you pumping out a radio wave to getting it back. Meanwhile visible light is always deflecting off everything in the system at C(Assuming there's any kind of light source in the system).

Keep in mind per the series the photo's are taken, scanned, routed and reported in under five minutes. That would take five minutes if you don't know the system since you need to track everything in the system, build a projection model(Which has tens of thousands of ship sized objects) to track how fast the rocks are going and where they should be at current speed.

A simple Perl script won't do that.

[Beowulf]

The problem with trying to blind enemy sensors is you're still pumping out energy that can be traced back to its radiant source (you). You're not going to be able to convince the enemy missile you're somewhere you aren't, not if it's programmed competently, because no matter which way you're looking at it you're sillhoutted against a basically unchanging featureless background. You could try completely burning out the enemy's sensors with lasers though.

You're assuming the radiant source is in fact you. Why couldn't it be some kind of drone you release from your ship?

Because if the drone is have the same signature as your ship, it's going to have to weigh the same as your ship. Otherwise the emission signature of the drone's drive is going to be different than you. If it's got the same brightness (so as to match your ship's actual thrust), it will accelerate faster (different doppler shift). If you try to maintain a similar acceleration, it's going to be dimmer (not as much thrust).

[Samuel]

The problem with trying to blind enemy sensors is you're still pumping out energy that can be traced back to its radiant source (you). You're not going to be able to convince the enemy missile you're somewhere you aren't, not if it's programmed competently, because no matter which way you're looking at it you're sillhoutted against a basically unchanging featureless background. You could try completely burning out the enemy's sensors with lasers though.

You're assuming the radiant source is in fact you. Why couldn't it be some kind of drone you release from your ship?

Because if the drone is have the same signature as your ship, it's going to have to weigh the same as your ship. Otherwise the emission signature of the drone's drive is going to be different than you. If it's got the same brightness (so as to match your ship's actual thrust), it will accelerate faster (different doppler shift). If you try to maintain a similar acceleration, it's going to be dimmer (not as much thrust).

They actually point out the same exact thing in atomic rocket- essentially, a drone will have to be about as expensive as a real ship, the only difference being weapons and crew, in which case, why have it be a drone?

Now, you might be able to "hide" ships in a large number of ships so your enemies can't count them, but actual stealth isn't going to work.

[Junghalli]

^ As I understand DW's idea, it was to put a bunch of lasers on a drone and use them to "dazzle" the sensors of missiles so they can't see anything.

[Samuel]

^ As I understand DW's idea, it was to put a bunch of lasers on a drone and use them to "dazzle" the sensors of missiles so they can't see anything.

I think that lasers are so compactable. They have the problem with waste heat, which means they will be about of expensive as missiles. Besides, how does this differ from point defense?

[Junghalli]

Besides, how does this differ from point defense?

It probably takes less power to blind sensors than the destroy the missile.

[Count Chocula]

Beowulf wrote:

Because if the drone is have the same signature as your ship, it's going to have to weigh the same as your ship. Otherwise the emission signature of the drone's drive is going to be different than you.

It's pretty easy to get a larger signature than your ship, if you're dealing with radar; from what little I've read, radar as an active system will be even more useful in space than on Earth. We did anti-radar countermeasures in WWII with bombers dropping tinfoil confetti, and the B-1 uses an ALQ-50 towed decoy that has a radar signature several times larger than the B-1 itself.

Thermal countermeasures, IMO, would be more applicable during the approach and actual combat. Any drive using technology we understand would have a very obvious thermal bloom, which would be easily detected by IR sensors. Let's say the incoming ship, knowing it will be detected, keeps its own IR arrays on the lookout for drive flares from defensive missiles or vessels. Given relative velocities of, say, 40,000MPH (just over twice Earth's escape velocity), engagement distances will be at tens of thousands of miles, if not longer. In that scenario, the attacking ship could launch magnesium or thermite burning decoy missiles that would produce much larger signatures than its own drive puts out, thus luring defensive missiles off target - much like the flares on today's military aircraft.

Edit: Regarding superconductors, I don't see them really helping all that much in recovering heat generated from, say, an atomic-steam power plant. Superconductors are exciting because you can conduct the same amount of electricity as, say , #2 wire on a #22 wire, but its chief advantage lies in the transmission of electrical energy, not thermal energy. With superconducting current-carrying wires, you could reduce the weight of your power plant, but to get more power out of (again) an atomic-steam plant you would need to run the working fluid and turbine(s) at higher temperature and pressure, something I'm not sure superconductors could help achieve.

[Darth Wong]

Because if the drone is have the same signature as your ship, it's going to have to weigh the same as your ship. Otherwise the emission signature of the drone's drive is going to be different than you.

Since when can we magically detect the mass of a distant drone? All we can see is light coming from it, and it's not going to produce enough gravitational effect on its surroundings to derive it from the movement of planetary bodies. Are you saying that the mass has to be the same so that the light and heat radiated from it is the same? Why can't you simply actively emit more light in the direction of the sensor?

[phongn]

In that scenario, the attacking ship could launch magnesium or thermite burning decoy missiles that would produce much larger signatures than its own drive puts out, thus luring defensive missiles off target - much like the flares on today's military aircraft.

The problem is those missiles should be able to recognize that those bright decoys do not match the signature of a warship and ignore them (modern IIR missiles are capable of doing the same thing). Signals processing is becoming extremely sophisticated.

[Samuel]

The drive emissions. It is mass dependant so you can't fake it.

[Count Chocula]

If we can acheive a sophisticated enough technology to make practical starships, and starship engagements possible, it would be child's play to design drones that mimic the thermal or electronic signature of the vessel they're defending; combine drone maneuvers with defensive maneuvers by the targeted ship, and there's a chance the drones would draw missiles away from the targeted ship.

[JointStrikeFighter]

Thermal countermeasures, IMO, would be more applicable during the approach and actual combat. Any drive using technology we understand would have a very obvious thermal bloom, which would be easily detected by IR sensors. Let's say the incoming ship, knowing it will be detected, keeps its own IR arrays on the lookout for drive flares from defensive missiles or vessels. Given relative velocities of, say, 40,000MPH (just over twice Earth's escape velocity), engagement distances will be at tens of thousands of miles, if not longer. In that scenario, the attacking ship could launch magnesium or thermite burning decoy missiles that would produce much larger signatures than its own drive puts out, thus luring defensive missiles off target - much like the flares on today's military aircraft.

Stuart would inform us that missile seekers these days have suficient computing power to simply ignore flares. The missile see's a normal heat signature on locks on, then it sees ZOMFG HUGE THERMAL SIGZ shoot off at 90 degree's to the original target, its a safe bet that those are decoys, ignore that sht.

[Strider]

Would it be possible (I'm not saying in any way easily feasible, just possible) to use a laser as your means of propulsion (photon momentum) to prevent your reaction mass giving you away, and to put your engine at the focal point of a large parabolic infrared light mirror so that all the infrared light from waste heat was directed in a single direction (ideally, the same one as the laser)? Of course you'll never get it to be perfect, but I wonder if you could get it quiet enough to make it worth it.

[phongn]

If we can acheive a sophisticated enough technology to make practical starships, and starship engagements possible, it would be child's play to design drones that mimic the thermal or electronic signature of the vessel they're defending; combine drone maneuvers with defensive maneuvers by the targeted ship, and there's a chance the drones would draw missiles away from the targeted ship.

No, it's not child's play. The engine signature is going to be massively different for a variety of reasons and cannot be spoofed. Electronic signature might be forgeable but there are various other factors that simply can't be easily hidden, and become worse once you apply sensor fusion/hyperspectral sensing to the mix.

[Junghalli]

If we can acheive a sophisticated enough technology to make practical starships, and starship engagements possible, it would be child's play to design drones that mimic the thermal or electronic signature of the vessel they're defending

The problem is that (as I understand from Atomic Rocket) it should be fairly simple to measure the energy the drive is putting out by observing the exhaust plume, compare it to the acceleration, and from that determine the mass of the vessel. To mimic the exhaust plume you need to expell the same gasses at the same temperature in the same quantity, and if your decoy has lower mass this will result in it accelerating faster than your ship, which will give it away. If you try to cut back the thrust so the acceleration is the same the exhaust plume will look different.