Space Warfare II - Stealth Reconsidered

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

I just hate that your website is blocked at work, Nyrath.

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

And listening isn't my problem; comprehending is my problem. I apologize if we are constantly repeating tired old arguments. Believe it or not, I am learning something.

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

The current state-of-the-art solar cell arrays on the International Space Station are about 14.5% efficient. This means (in Earth orbit) every square meter of solar cell produces abotu 198 watts of electricity' date=' and 1167 watts of waste heat.[/quote']

Somewhat less, actually; solar cells aren't black, so it might be producing something like 1000W of waste heat and 167W of reflected light.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Somewhat less' date=' actually; solar cells aren't black, so it might be producing something like 1000W of waste heat and 167W of reflected light.[/quote']

True.

Of course as far as stealth is concerned, reflected light is about equally bad to waste heat.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

I just hate that your website is blocked at work' date=' Nyrath.[/quote']

Hrn. I wonder why? Does it give a reason?

 

At my work they use SonicWall, it blocks all sorts of sites under forbidden categories like "firearms". But it lets my Atomic Rocket site through.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

And listening isn't my problem; comprehending is my problem. I apologize if we are constantly repeating tired old arguments. Believe it or not' date=' I am learning something.[/quote']

I apologize if I came across as a little bit testy.

But as you figured, yes these are the same tired old arguments.

 

Indeed, this entire thread is a shining example of Nicoll's Law: It is a truth universally acknowledged that any thread that begins by pointing out why stealth in space is impossible will rapidly turn into a thread focusing on schemes whereby stealth in space might be achieved.

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

Well, just keep in mind that some of our dreams are bigger than our brains.

 

Also; how the fark am I going to sneak up on my damned players if all my ideas get shot down?

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Also; how the fark am I going to sneak up on my damned players if all my ideas get shot down?

You tell your players that the campaign is set in the SciFi universe of your choice where stealth exists but scientific accuracy does not. Problem solved.

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

You tell your players that the campaign is set in the SciFi universe of your choice where stealth exists but scientific accuracy does not. Problem solved.

 

Meh, too easy.

[Clonus]

Re: Space Warfare II - Stealth Reconsidered

 

Well, just keep in mind that some of our dreams are bigger than our brains.

 

Also; how the fark am I going to sneak up on my damned players if all my ideas get shot down?

 

Just remember, FTL changes everything. Superscience in general does that. Once you can pop out of hyperspace, turn on your cloaking device and sneak around using your reactionless drives, the laws of the universe are whatever you say they are.

[L. Marcus]

Re: Space Warfare II - Stealth Reconsidered

 

You could always just dump your excess heat into subspace.

[Blades]

Re: Space Warfare II - Stealth Reconsidered

 

I assume your trying to approach an enemy without being detected.

I dont think there are any long term solutions without resorting to Sci-Fi solutions. But there can be short term solutions. But most of them require knowing where the enemy is located in advance.

 

Reflected light can be reduced by painting the ship with absorbant colors, ie black. That will reduce the visual reflection to about 1%, still detectable when you get close enough.

 

Visual light will be re-radiated as IR light, and the internal heat of the ship will also radiate as IR heat. Most forms of engines will both raise the heat of the ship and leave a trail of hot gas/plasma/ions behind that are also detectable, so most of the approach to the enemy needs to be coasting at a high speed.

1) mount a probe off the bow (in the direction of the enemy), and use it to spray a cold mist of H2. Some of the IR photons will go straight through, but some will hit the H2, and be re-radiated and a cooler frequency at random directions. The result could mask probably 95-98% of the IR signature, untill the H2 runs out.

2) since it is Sfi-Fi, use a force field in front of the ship that is opaque to photons, then no reflected light or IR signature.

3) arrive on the far side of the sun from the target. Dive past the sun and approach from the sun side of the target, perferably with the sun directly behind or slight offset. I dont think any IR detection system could pick out your appraoch aiming directely into the sun.

 

The ship will still pass in front of distant objects as it closes. For a small fast ship that is a little careful in its approach, this is not a very big problem. For a big ship or ship making slow approach, this will eventurally revield the ship, but not quickly. The enemy is also moving and that will occasionally cause stars to be occluded. So the enemy would have to keep a 360 watch and use powerful computers over time, to identify several times that the approaching ship occuded stars to prove it is there and estimate its course. So if the approaching ship can approach in days, it will probably not be found this way, but if it takes months, it will be found.

 

All the electrical motors on the ship radiate an EM signature. So every toaster, electric razor and electric watch all contribute some to the ships EM signature. But I presume the power source (and the electrical Generators off the power source) and drive engines cause most of the radiation EM. Unless a Sci-Fi force field can block it, at some point, it can be detected. So powering off most electronics will be required during approach

 

So my point is that an approaching ship is not invisable, but if it can make ita approach in a couple of days (instead of months), it should be able to get within several hours of a target or closer before detection. At some point it will be detected, but it may already be in long weapon range.

 

Note that this was assuming a coasting ship. It will probably still need to slow down unless it is only making one pass.

[Zeropoint]

Re: Space Warfare II - Stealth Reconsidered

 

It's a mistake to focus entirely on WASTE heat, too. Even if you're not using your engines, assuming that your ship is in steady state, every joule of energy produced on board--including the heat generated by the crew--is going to have to be radiated away.

 

If your power plant is 100% efficient, and putting out 1MW of useful electricity and NO waste heat . . . that megawatt has to be going somewhere. If it's charging a battery or capacitor bank, for example, then your ship isn't in steady state. Eventually that battery or capacitor will be full. Every piece of equipment that draws power is turning that power into heat, either directly or indirectly. A fan, for instance, turns some power into heat through resistance, some through friction in the motor, and (hopefully) turns most of the power it uses into kinetic energy of the air it blows. That moving air will turn the kinetic energy into heat through friction.

 

It comes down to conservation of energy. If your reactor turns some mass into 1 megajoule of energy every second, that energy MUST be entirely accounted for by one of three things: being turned back into mass, raising the energy content of the ship, or leaving the ship via easily detectable emissions.

[Zeropoint]

Re: Space Warfare II - Stealth Reconsidered

 

Reflected light can be reduced by painting the ship with absorbant colors, ie black. That will reduce the visual reflection to anout 1%, still detectable when you get close enough.

 

That's some pretty darn black paint! Also, it should be noted that 75% of known asteroids have an albedo of about .03 (that is, they reflect 3% of the light falling on them) and we, obviously, have seen them from here.

 

That's kind of a moot point, though . . . for anything with a power source on board, infrared radiation is going to dramatically exceed reflected visible light.

 

You CAN, of course, invoke various kinds of sci-fi handwavium, but once you step outside the rules of known science, all bets are off. From a scientific viewpoint--as opposed to a dramatic or game-balance viewpoint--a perfectly opaque non-reflective force field might as well be a magic spell of invisibility.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Just remember' date=' FTL changes everything. Superscience in general does that. Once you can pop out of hyperspace, turn on your cloaking device and sneak around using your reactionless drives, the laws of the universe are whatever you say they are.[/quote']

Yes, but then you have to be very careful not to go too far the other way.

 

Say that your FTL lets you go from any point A to any point B with no limit, and your ship is undetectable while in transit. The result is that most interstellar wars would last about five minutes.

 

The first warning that the Cyber-octopoids of Gamma Privia V have of a declaration of war from the Blortch of Delta Slimeball III is when a flight of Blortch space bombers pop out of hyperspace over Privia and carpet bomb the place with planet-cracking warheads.

 

The flight of space bombers then make the jump home to Slimeball. Only to discover that in the ten minutes they were away, a flight of Cyber-octopoid bombers had coincidentally given the same treatment to Slimeball. The End.

 

The reader takes the novel and hurls it across the room.

 

This is why powers in the Hero System have limitations.

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

It is also a darn good reason why I believe that if there is other life out there, they probably are no closer to cracking FTL than we are.

 

But I do like making sure any handwavium I use is at least rooted in some real science; that it be plausible.

 

--

 

Now, another thought, which isn't exactly true stealth, but could be used to gain an advantage...

 

It would take someone a bit to detect your ship. There are probably thousands of objects in our solar system we have yet to detect, simply due to the massiveness of space. With more advanced detection methods, this will probably be of less benefit, but I can imagine that a ship using as much of the feasible "stealth" we have mentioned here might be more likely to slip through the grid, but would be more luck than skill or tech - having nobody looking in your direction. Not reliable, but could be the hook for a story or adventure.

 

"Commander, we don't know how we missed this, but we have an unknown craft entering orbit..."

[Kristopher]

Re: Space Warfare II - Stealth Reconsidered

 

Yeah' date=' you are. Any device that doesn't produce any waste heat is a perpetual motion machine.[/quote']

 

Superconductors?

 

An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source. [1]

[Kristopher]

Re: Space Warfare II - Stealth Reconsidered

 

That's some pretty darn black paint! Also, it should be noted that 75% of known asteroids have an albedo of about .03 (that is, they reflect 3% of the light falling on them) and we, obviously, have seen them from here.

 

That's kind of a moot point, though . . . for anything with a power source on board, infrared radiation is going to dramatically exceed reflected visible light.

 

You CAN, of course, invoke various kinds of sci-fi handwavium, but once you step outside the rules of known science, all bets are off. From a scientific viewpoint--as opposed to a dramatic or game-balance viewpoint--a perfectly opaque non-reflective force field might as well be a magic spell of invisibility.

 

I'm of the opinion that you can have some conceits for the sake of story, without throwing the entire science book down the toilet, as long as you're fairly careful about consistency and limiting it to what's really necessary for the worldbuilding.

[Zeropoint]

Re: Space Warfare II - Stealth Reconsidered

 

An electric current flowing in a loop of superconducting wire is . . . a permanent magnet, basically. It might make a good energy storage device, but it's certainly not a power SOURCE. As soon as you use it--place a load on it--the current will start dropping off rapidly, until there's none left.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Yeah' date=' you are. Any device that doesn't produce any waste heat is a perpetual motion machine.[/quote']

 

Superconductors?

 

An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source. [1]

 

From http://www.kilty.com/pmotion.htm

Superconductivity also seems to be an example of a process that runs forever. Most physics textbooks explain that superconductivity is not perpetual motion because it is not a classical effect. It is a macroscopic quantum effect--sort of like a room sized atom, and we know that atoms are forever. They do not "run down." However, it seems to me that the unavoidable imperfections in the superconductor and its enviroment almost guarantee that this macroscopic atom will eventually stop.

[Kristopher]

Re: Space Warfare II - Stealth Reconsidered

 

The original statement was that any device that doesn't produce waste heat is a "perpetual motion machine". I was only wondering if a superconducting loop would produce waste heat, and if not, would it be a "perpetual motion machine"?

 

Because at that point, either you have an actual "PMM" in existence, or you have something that doesn't produce waste heat and is not a "PMM" -- calling the "no waste heat = PPM" definition into question.

 

I understand that putting a load on the superconducting loop would cause it to run down, would "draw energy out of the storage device".

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

Another way to look at Superconductors, I have been told, is to see them as merely a 100% efficient medium for energy transference.

 

Conservation still applies - they can't create energy, you can't get more energy out of them than you put it, and as soon as your energy is in a non-superconductive medium, you would see the same loss.

 

Something like that. High efficiency simply reduces the amount of waste, it does not eliminate it nor does it allow you to break the usual laws.

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

Superconductors would have non-zero losses due to environmental effects, though the time scale would be very long. In any case, the real issue is that, if you put energy into a device, it has to come out somewhere. This is often in the form of waste heat, but might not be if the device has some other discernible output (for example, most of the energy put into a radar comes out as radio waves).

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

The original statement was that any device that doesn't produce waste heat is a "perpetual motion machine". I was only wondering if a superconducting loop would produce waste heat, and if not, would it be a "perpetual motion machine"?

 

Because at that point, either you have an actual "PMM" in existence, or you have something that doesn't produce waste heat and is not a "PMM" -- calling the "no waste heat = PPM" definition into question.

OK, you are going to get more information that you wanted.

 

There are three classes of perpetual motion machines:

 

Class 1: This produces energy from nowhere. It violates the law of conservation of energy.

 

Class 2: This converts waste heat into useful energy. It violates the second law of thermodynamics.

 

Class 3: This eliminates friction and other dissipative forces so an object moves forever. It does not violate any laws, but is not generally very useful.

 

A superconductor is a perpetual motion machine class 3. A machine that does not create any waste heat is a perpetual motion machine class 2. The latter is the one being discussed.

[Cancer]

Re: Space Warfare II - Stealth Reconsidered

 

I think the only way to go undetected in space is for parties from whom you are trying to conceal yourself not bother (or be not able) to look in the relevant way. (And to give them strong reasons to avoid coming to the correct conclusions.)

 

We're now back to social limitations, not physical effects. In this context, this makes for interesting reading.