Wanted: concepts for "realistic" SciFi

[oberon]

sgi+, it's the energy requirement for getting up to lightspeed that prompted me to post some little things about catastrophe theory and potential wells. Since spacetime is a manifold, there may be a way to visualize level curves, standing for energy levels, on the surface of it. If your drive can "jump" between energy states, or find a gradient, then there is some hand-waving for you. If your ship can "fall off" the manifold then back on, skipping the part that requires energy to get in and out, then there's some more hand-waving. The velocity of a flow particle goes to zero as the particle approaches an attracting fixed point (or limit cycle) which is a way of saying that it will never reach that point in finite time, even if the velocity vector points always toward the point (which it does by definition). If there were some way to jump again, say, if you reach some critical point so close to the fixed point that the energy to make the jump is low enough, there could be a way. I don't know that I can think of the details, but the mechanism could be something like this. If the universe is curved and curves back on itself (since it's connected, it has to), may there perhaps be a way to point your ship off the planar surface, and enter some kind of hyperspace that is a straight line, like a chord inside a circle, and get there quickly? Since there are an infinitude of paths you could take, the universe is not one simple surface, and perhaps there are ways to change the manifold you are on. If you found a way to travel inside a torus, then you could reach any point quickly--for what is in front of you is also behind you, and if it's far one way, then it's near the other way.

Of course these may require energy too, and the energy requirements aren't going to be any less than for "regular" light-speed travel, except maybe the idea about waiting until you can jump to a fixed point at some critical, low-energy spot could be workable.

But what if your sci-fi world didn't have FTL travel? What if you ran into the anomalies and wonderful, mysterious things in space without explaining everything away in mock-scientific terms? I've posted in ASVS before about how one thing about ST that bugs me is everyone's lack of awe and wonder when facing the unknown and the infinite. Everybody just takes everything for granted, the way they take their survival in any situation for granted. Would there not be enough stories to go around on a warship with a sizable, diverse crew, worrying about surviving in space, repairing their boat, finding replacement parts, getting along, living and getting sick and dying and facing the utterly unknown?

What if ships used the black hole at the center of the galaxy to get propelled to other galaxies? What if, in your sci-fi, someone had actually gone into a black hole (say, Cygnus X-1, to show a baby step staying within the Milky Way), did just that, then traveled through another black hole to get back, and thus give us empirical evidence about what black holes really were and show that they can be used to get around quickly? What if these holes really were holes and not simply Cauchy singularities, and were, in fact, dimensional gateways? What if it was a closely guarded military secret that allowed humans to spy on and lightning-raid far-off races that would have no idea where the intruders came from or how they got there, because those other races were as terrified of black holes as we would be now? A story could rely on black holes for this, instead of accepting current black hole theory as everyone else does.

[Darth Wong]

I don't think that any of this handwaving about pseudoscience FTL techniques will accomplish squat. Better to just call it "hyperdrive" or something and be done with it.

I think the real questions relate to tactical balance, techniques of spacecraft piloting and use, etc. If you want a quasi-realistic sci-fi series, think outside the box. Forget Star Wars, Star Trek, and B5. I suggest the following:

1. Forget shields, spray defenses, armour, etc. In a realistic sci-fi universe, spaceships would be small and nimble. The idea is to avoid the hit.
2. Fleet carriers would not approach one another. They would launch their fighters from extreme distance, because they are large targets and they are so vulnerable to attack.
3. Fighters would be very far apart from one another; probably beyond naked-eye range. There is no conceivable reason to fly around in formations where the fighters are just 50 metres apart.
4. Fighter combat would take place with area-effect low-yield nuclear missiles. You don't bother trying to hit the other guy; you just want to get a missile in his neighbourhood before he gets one in yours, because the area-effect detonation will take him out easily.
5. Sensor stealth will be of utmost importance. Simple techniques like light-absorbing/radar-absorbing paint, reduced emission signatures, radio silence, etc. are vastly preferable to magic cloaking devices.
6. Smart mines which passive detect intruders, power up engines, and home in on their targets will be the preferred method of area denial. Space is much too open to saturate with stationary mines.
7. No transparent cockpits in fighters. There is no realistic way to protect the pilot's eyes from the flash of a nuclear detonation even at rather long range in space. They use cameras and instrument-guided flight, and if they need to look outside, they can draw a protective shield back from a portal.
8. ECM would rely heavily upon decoys.
9. Possible defensive measure against imminent proximity missile detonation is an opaque cloud sprayed out in the direction of the blast. It will absorb much of the radiation, thus protecting the fighter. By having a limited number of these defense clouds onboard, you can create more suspense as the battle wears on.

I know this sounds less dramatic than what we're used to seeing, but while it wouldn't work on a TV screen, I think it could easily be made to work in a book. Instead of a fighter pilot seeing his wingman blown to smithereens with the naked eye, he sees dots heading toward his squadron on his tactical display. The tension comes from the inevitability of the lethal missiles coming into range, the slow depletion of your defense clouds, the desperate maneuvering to put as much space between yourself and an incoming missile as possible, so it won't overwhelm your defense cloud. Etc.

Of course, that might not be what he wants to do, but it would be realistic. What you guys have been talking about is ways to duplicate SW technologies and methods with technobabble. That does not make it any more realistic.

[Pablo Sanchez]

Of course, that might not be what he wants to do, but it would be realistic. What you guys have been talking about is ways to duplicate SW technologies and methods with technobabble. That does not make it any more realistic.

Sounds like a cross between Larry Niven and submarine warfare.

Anyway, I have a suggestion:
If you choose to have ships that can move at high sub-light velocities, a good strategic weapon would be simple iron projectiles. At fractional C velocities, they'll do a fair bit of damage to anything they hit. Time dilation makes it hard to hit anything smaller than a planet, but sometimes that's just what you need.

[Shaka[Zulu]]

Ive got a few things to add to your list...

1. I know you already addressed stealth... so take it as a bit of a modification... small, high performance fightercraft are nice, but stealth is better given the weapon types you advocate (area-effect low yield nukes). Unfortunately, making fighters fast & nimble enough to get out of effective blast range of a nuke would ruin any chance of stealth due to Power & Propulsion emissions... you want your adversary to not know where you are (ever), or at least minimize the accuracy of his firing solution, so that he has to either a) give his own precise location away by going active b) wait for you to give yourself away -- which probably wont be until you have what you think is a good solution, which might be _very_ bad for him or c) saturate as much space as he can with his nukes in what would likely be a vain attempt to flush you out, and risk exhausting his ordnance supply -- also _very_ bad for him.
2. the aforemention nukes have a serious disadvantage in space... effectively no medium through which to transmit a shockwave, which is the principal cause of damage when a nuke is detonated within an atmospheric envelope. Yes, there is radiation, and a small shockwave due to the now gaseous material that made up the weapon casing and internal mechanisms, but in a vacuum, such effects from any low-yield weapon will fall off _very_ quickly, blending into the natural environment within a few tens of kilometers. The EMP from such a blast could have serious consequences for electronics over more substantial distances, but that depends on the proximity of the blast, the quality of any shielding (of the electronics) and the nature of the vessels electronics in particular -- for example, the fastest space-rated CPU in general use for missions that pass thru the Van Allen belts is still the venerable Intel 386 (the rad-hardened version) iirc... computer systems built on current technologies prevalent in the western world are highly susceptible to radiation and EMP effects, and are _extremely_ expensive to qualify for use in space or other high rad environments. OTOH, technologies based on vacuum tubes iirc are nearly immune to such issues (hence their use on certain russian combat aircraft designed to take on our bombers during the cold war...) but they have certain mass & power penalties associated with their use. I hate to say it, but the best way to guarntee a kill is nice, solid contact.

I cant think of anything more at this point, except that the combination of our 2 posts sounds alot like the Brilliant Lances game in Traveller: The New Era, with the optional Fire, Fusion & Steel rules (the original book -- not the 2nd edition, as the original is far more thorough in its' descriptions of those systems which _do_ exist...) basically, stealth is king, missiles are long range (out to multi-csecond ranges), all other beam & projectile weapons are limited to an effective range of 1csec or less, and sensor systems can get Obscenely large (Arecibo-sized arrays anyone?)... think an outer space version of submarine warfare...

[His Divine Shadow]

I still like my Laser cannon and reflective armor idea and ways to deal with excess waste heat.

[sgiathach]

Okay, after digesting the latest posts, let me put it through the meat grinder...

@ Mike: I don't want to simulate SW by technobabble. I just want to avoid inconsistent energy figures as seen in ST. Anyone can just say "my ship's main gun delivers eleventy gazillion megawatts" and stuff like that. I just want to make sure whether that much power can be supplied without resorting to magic (ever thought of how many Ah an ST phaser would pack?). But I agree with you on many points, such as the importance of tactical balance.

Propulsion: I think I'll opt for the Jump idea now, using some of oberon's ideas. Particularly I'm thinking of natural Short Wormholes and artificial Jumpgates. This should make for a very interesting 3D-map, as two systems 50LY apart may belong to the
same faction, but directly adjacent systems could be unreachable by direct means (so you have to detour etc. - think of the wormholes in the Frontier game).

Power: problem solved, if we presume that opening a jump tunnel takes a lot less energy than direct flight; and this energy may often be provided externally. Annihilation should be fine as source.

Stealth: there will be no cloak shield, but sensor jamming, light and sensor camouflage, the whole works. I always wanted something like submarine warfare in SciFi, and other than "captain, a ship is decloaking--" ... Different ship types will incorporates those technologies to a variable degree.

Weapons: there will be (dumbfire) energy cannon and (homing) "hard" missiles, some of them using AM warheads; plus hybrids as I described before, to deliver AM charges by cannon. As there will be many civilizations and factions, only the most advanced ones will have AM tech. There can be real lasers and derivatives thereof, as well as cannon which fire at sublight speed but would have other advantages.

Protection: I like Mike's idea of defensive clouds, ECM and decoys, but I'll also incorporate other defensive tech. One idea that re-emerged yesterday are autonomous drones that circle the vessel at short distance, to intercept incoming fire. Maybe I'll kick out energy shields altogether, because they've been seen too often.

Danger: I agree that low risk means low tension. The whole space business should be hazardous. Also, I deal with relatively small ship quantities, so that every destroyed ship means a severe loss to the respective faction. This would logically lead to captains preferring flight to destruction, at least if the battle is only for resources.

Military ships: I have already developed the composition of two navies. Examples with length, main guns, and designations:
- Escort Frigate - 300m, 2 big main guns, used as sector defense ship
- Assault Frigate - 350m, 1 medium AM gun, offensive operations
- Man-o-War - 100m, 1 light AM gun, high stealth, strike ops and commerce raider, the "U-Boat" of the navy.
- Destroyer - 500m, 1 heavy AM gun, fighter wing, task force command ship & carrier
- Dreadnought - 1500m, 4 heavy EM guns, fighters, semi-stationary sector defense
- Fighter - 20m, 1 light EM gun, ranged strike and defense

Civilian ships: mostly freighters, rely entirely on jump tunnels, often rather chunky basic design (remember the Monolith freighter of Privateer 2?), though tramp freighters on remote routes would have increased defensive capabilities built around the cargo bay.

Which brings me to another topic:

Economics: there must be a business in space travel. If all the expensive tech and fuel and maintaining strong navies wasn't profitable, no-one would do it. Okay, colonies would be established, but they would be rather isolated and keep to their own system. But I'm talking about interstellar trade. The question is: how can a free trader crew _afford_ their own ship? Even a low-end model would require loans equivalent to many year's income of a normal person. Look at yourself: could you afford to buy a semi? Maybe. Also an ocean freighter? Hardly? Or a 4-engine jetplane? No? And, if you could, wouldn't you have enough dough already to live off the interest? But going further, a space shuttle would cost even more. An imaginary interstellar ship must have a _horrendous_ price, because if it was halfway affordable, the lower-tech transports (plane, ship, truck) would have to be proportionally cheaper, and a 40-ton rig would cost about one hamburger.

Objections, opinions and solutions, as always, welcome.

[sgiathach]

Just tripped across this, posted in Science forum:

>> Ignorance makes for a nearly impenetrable armour.

NOW I know what to employ!

[oberon]

Thanks, but like Mike says, you don't have to explain how it works. If you have little snippets come out in technobabble (read Mike's example of Apollo 13's technobabble--they use short, informal words and don't rattle on about what a "bus box" does), then that would be good, and if my ideas help it sound original, then great! But it's the way Star Trek tries to explain the unexplainable down to its nuts and bolts, all without the educational grounding that could make some of it sound halfway decent, that contributes to it being crap TV.

If a ship is small and lightweight, then defense drones might be a little silly. I saw a Heavy Metal story (Machonismechs) that used these, but the system belonged to a very large, very heavily armed and armored dreadnaught of a gravtank. A simple passive system of armor plates would probably be most realistic, as it would be cheap to produce above all else. One thing about this is the way we think: we are not going to start exploring space with ships that are armored with X, Y, and Z capship grade defenses and armor, at least until we meet a need for it. So you could fully have your first explorers getting killed until we make newer ships that can meet a potential threat; and any improvements would be guided by intelligence and threat assessment. Note that now, we have more powerful weapons delivery systems than ever, yet in the 1980s, our ships were the lightest they have ever been. But after a couple minings and missle hits, we went back to steel armor--yet again, the ships are still relatively small and light.

I also think that it would be interesting to see the ping-pong ball-like changes in motion imposed on small, nimble ships by impacts, which of course we have never seen in a mainstream sci-fi show.

[sgiathach]

Some new thoughts:

Reflective armour - as proposed by His Divine Shadow - would make the ship highly visible, it would shine like a christmas tree. This would be the opposite of space-uboats. Thus, it would only be suitable for certain types of ships.

As for the Stealth: dealing with waste heat has been mentioned as a problem, and with full right. The only solution is to radiate it into space some way or other . Which takes us to the next problem: infrared sensors will easily spot a ship, despite various optical and electronical stealth measures.

Propulsion: I like an idea that is, again, inspired by the Frontier short wormholes. The systems connected through these shortcuts may be dozens, even hundreds of LY apart, and yet be easily accessible. Thus, to fly from System A to System B 10LY away, you may have to jump via System C, 200LY far, etc.

Defense: the Drones would be for autonomous starships, e.g. 50 or 100m length and up - _not_ for fighters. The drones may be as small as 1m in diameter or as large as a small fighter craft for capital ships.

History: the scenario narrative for my universe will be a few centuries into FTL travel, maybe 300 years. Many species have already met or collided, alliances have been founded, wars have been waged. Thus, the dangers of space travel are widely known, and ships will have as much self-protection as viable.

Ping-pong: cute idea. Reminds me of how I once explained to a trekkie that some sort of impenetrable "warp shield" he came up with would be quite useless, as a hit might not damage a cap ship but shoot it around like a snooker ball.

Economy: I still don't know how anyone less than a planetary power could afford interstellar spacecraft.

[His Divine Shadow]

Reflective armour - as proposed by His Divine Shadow - would make the ship highly visible, it would shine like a christmas tree. This would be the opposite of space-uboats. Thus, it would only be suitable for certain types of ships.

Hardly, there is no such light in space, only near planets, it wouldn't look like the Naboo spaceship at all, it would look black with stars on it, kinda like an optical cloaking device infact.

[sgiathach]

Hardly, there is no such light in space, only near planets, it would look black with stars on it, kinda like an optical cloaking device infact.

Okay, I'm not an optics expert, so are you sure about this? Well if I think about it a little (you don't see a mirror at night except light shines on it), it makes sense.
But, if I were an engineer, and got word about such an armour used by my nation's enemies, the first thing I'd do would be developing a Search Beam device to discover such ships. It would shoot harmless laser beams in all directions until the disco ball flashes up.
Basically the same as airplanes discovered by flak spotter beams.

Also, I haven't decided yet to what extent energy weapons are used (as compared to particle weapons). However, it compares to a piece of scenario history I already wrote:
at some point, major power A introduces a new shield type, the Phase Shield. It is virtually immune to all weapons developed so far. Then, power B counters with the introduction of the Phase Transit Cannon (PTC), which practically ignores Phase Shields, and works normally against other defenses.
Logical consequence: phase shields are discontinued, regular shields are re-introduced by A, the PTC remains in use.

Another weapon type I want to use will be EMP-weapons, from E-grenades for close combat over E-bombs for ground combat to maybe E-torpedoes. Questions:
- to what extent can you rad-harden various equipment?
- Does rad-hardening prevent damage from EMP at all?
- Is EMP an all-or-nothing effect, i.e. an item stops working or it is not affected; or can there be a gradient?

[Mr Bean]

I can answear number three, EMP is never all or nothing its always gradual

However its been noted most electrial sytsems gradual fail after being EMPED if they survived the first shot

[sgiathach]

Good to know that about EMPing.

Just played with the relativity calculator and wrote up some key sublight speeds/fx to a handy list.

I find one part especially stunning: that the relativistic KE is higher than the mass energy equivalent beyond ~2.56E8 m/s.
(too bad you can't accelerate an object to this speed for free and then use the RKE as power source)

a note on the side: mass and time dilation figures suggest that 100.000km/s (0.3c) should be about the "top speed" for manned sublight flight, unless the SF involves some tech to counter the dilation fx.

[His Divine Shadow]

Okay, I'm not an optics expert, so are you sure about this? Well if I think about it a little (you don't see a mirror at night except light shines on it), it makes sense.

I am sure, because I saw it mentioned on badastronomy.com in the TPM review.

But, if I were an engineer, and got word about such an armour used by my nation's enemies, the first thing I'd do would be developing a Search Beam device to discover such ships. It would shoot harmless laser beams in all directions until the disco ball flashes up.
Basically the same as airplanes discovered by flak spotter beams.

Well a laser beam, nah, thats way way too much space to cover really, a really strong flash-light or something that covers a larger area.
I spose one could use it as a deployable type of armor around important areas, so it could retract if needed, ala enterprise and it's silly polarized hullplating.

at some point, major power A introduces a new shield type, the Phase Shield. It is virtually immune to all weapons developed so far. Then, power B counters with the introduction of the Phase Transit Cannon (PTC), which practically ignores Phase Shields, and works normally against other defenses.
Logical consequence: phase shields are discontinued, regular shields are re-introduced by A, the PTC remains in use.

That whole phase word scares me though

[Pablo Sanchez]

a note on the side: mass and time dilation figures suggest that 100.000km/s (0.3c) should be about the "top speed" for manned sublight flight, unless the SF involves some tech to counter the dilation fx.

It's probably a good idea to stick with that, except in a few special cases, like my suggestion for strategic weapons. The .9c attack on Wunderland from the Man-Kzin wars is a compelling story.

[drifter god]

i was thinkin about it and i realized, lasers and energy shielding may not be to far off from realistic space combat if you think about it. think about this, from the time it would actually take for a civilization to move from just exploring new worlds, to actually colonizing and establishing new governments is a really long time, so there is a lot of time for research and development. and dont even begin with warfare durring those times, it would be rediculous, lets say planet A and planet B go to war, the only battles that could really take place are the battles that occure at the midway point, it would be a complete stalemate until technology alowed for faster than light travel and industries developed ways to produce fighters and ships in mindboggling time. if planet A were to sent its compete millitary to planet B, all planet B would have to do is wait for them to get there, and it would be a slaughter, incoming ships from a far off planet dont stand much of a chance against a planet with resouces and orbital defence, etc. and say planet A wanted to bombard Planet B with nukes, chances are that technologies like radar and "scaners" would be able to detect inoming missles without much trouble, so shooting them out of the sky wouldnt be to hard.

so i think realistic space combat will include such things as light speed and phasers, because theres enough time to develop such things by the time a war would even possible. but hey, everybody is entitled to there own opinion.

[Patrick Degan]

I think the real questions relate to tactical balance, techniques of spacecraft piloting and use, etc. If you want a quasi-realistic sci-fi series, think outside the box. Forget Star Wars, Star Trek, and B5. I suggest the following:

1. Forget shields, spray defenses, armour, etc. In a realistic sci-fi universe, spaceships would be small and nimble. The idea is to avoid the hit.
2. Fleet carriers would not approach one another. They would launch their fighters from extreme distance, because they are large targets and they are so vulnerable to attack.
3. Fighters would be very far apart from one another; probably beyond naked-eye range. There is no conceivable reason to fly around in formations where the fighters are just 50 metres apart.
4. Fighter combat would take place with area-effect low-yield nuclear missiles. You don't bother trying to hit the other guy; you just want to get a missile in his neighbourhood before he gets one in yours, because the area-effect detonation will take him out easily.
5. Sensor stealth will be of utmost importance. Simple techniques like light-absorbing/radar-absorbing paint, reduced emission signatures, radio silence, etc. are vastly preferable to magic cloaking devices.
6. Smart mines which passive detect intruders, power up engines, and home in on their targets will be the preferred method of area denial. Space is much too open to saturate with stationary mines.
7. No transparent cockpits in fighters. There is no realistic way to protect the pilot's eyes from the flash of a nuclear detonation even at rather long range in space. They use cameras and instrument-guided flight, and if they need to look outside, they can draw a protective shield back from a portal.
8. ECM would rely heavily upon decoys.
9. Possible defensive measure against imminent proximity missile detonation is an opaque cloud sprayed out in the direction of the blast. It will absorb much of the radiation, thus protecting the fighter. By having a limited number of these defense clouds onboard, you can create more suspense as the battle wears on.

I know this sounds less dramatic than what we're used to seeing, but while it wouldn't work on a TV screen, I think it could easily be made to work in a book. Instead of a fighter pilot seeing his wingman blown to smithereens with the naked eye, he sees dots heading toward his squadron on his tactical display. The tension comes from the inevitability of the lethal missiles coming into range, the slow depletion of your defense clouds, the desperate maneuvering to put as much space between yourself and an incoming missile as possible, so it won't overwhelm your defense cloud. Etc.

Very much like ideas I've entertained for a more realistic SF war scenario, and a couple of wrinkles I handn't gotten around to thinking of.

As for not being exciting enough for TV, it could be if you concentrate the battle entirely from the POV of the heroes on the ship and make it very much like a submarine drama (like Das Böot —and indeed, I've often envisioned the submarine model as being the more likely analogue for space warfare). And remember, TOS made all of their battles work entirely with showing the action on the Enterprise and occasionally aboard the enemy ship, and only glimpses of either firing weapons. Using tension to create the battle on a low budget, I think, can work even more effectively rather than showng an outer-space Battle of Britain for the umpteenth time.

[gravity]

Of course, that might not be what he wants to do, but it would be realistic. What you guys have been talking about is ways to duplicate SW technologies and methods with technobabble. That does not make it any more realistic.

True, but if you *really* wanted to be realistic, your SF universe probably wouldn't have space combat at all.

[NecronLord]

Got to confess that I've used clarketech a few times (conversion reactors)

anyway. for realism you probably should use drones instead of fighters.

advantages
>nobody inside, no life support
>no casualties
>better accelleration and turning, even if you have inetial dampeners then they will teke up space
>no prisoners, it self distructs if captured, just have a bomb in the center, which once primed, detonates if tampered with, or if the drone looses power.
>smaller
>no fighter pilots to worry about = more space in carriers.

disadvantages
>need for detailed programming. not really an issue, if you have ever been beaten by a computer game at something think how much of a non issue this is for interstellar civilisations.
>llack of creativity. while with non AI this is true, number will make up for this in almost all circumstances.

[Enlightenment]

The rec.arts.sf.science newsgroup has gone into this question many, many times over the past decade or so. Looking up the various space combat threads through Google will provide a lot of material on physics-based STL interplanetary space combat.

To summarize:

Most all sensors will be passive far infrared systems designed to detect the blackbody radiation of other ships. Radar and other active systems need not apply due to the distances involved.

Currently existing far IR detectors are sensitive enough to detect the heat from the NASA space shuttle's OMS engines at a distance of 20 light minutes. In other words, a sensor in Mars orbit could tell when one of the space shuttles was in Earth orbit.

Anything that moves can be identified in fairly short order. Stealthing a moving object is basically impossible due to heat rejection requirements. Convincing mobile decoys aren't possible unless they mass as much as a real warship.

Fighters are a non-starter due to fuel requirements and mass ratio issues. Expendable missiles make much more sense.

The best way to kill anything at a range up to a light second or so is with a very large pulsed x-ray laser. Mirror 'armor' is useless against this kind of weapon.

The best way to kill anything at long range (more than a few light seconds) is with missiles. Guided KE rounds are one option; at the velocities required for a rapid intercept, the impact energy will be high enough for any kind of explosive warhead to be unnecessary. Another option is to use missiles armed with nuke-pumped x-ray lasers fuzed to detonate (and shoot at) the target once within laser range.

[NecronLord]

You're right on the fighters deep space fighters are pointless, They would only really be used in planetery support/raid/terror/specialist operations

[Patrick Degan]

Anything that moves can be identified in fairly short order. Stealthing a moving object is basically impossible due to heat rejection requirements. Convincing mobile decoys aren't possible unless they mass as much as a real warship.

Depends upon whether accurate enough mass detection sensors exist, and at long ranges, decoys would help hide a ship with all its stealth systems in place. They might not fool observers long-term, but perhaps long enough for your ship to get off the fatal shot. Even a momentary advantage can be invaluable.

[Enlightenment]

Depends upon whether accurate enough mass detection sensors exist, and at long ranges, decoys would help hide a ship with all its stealth systems in place.

Mass detectors aren't an issue here: the giveaway for lightweight decoys are the emission spectra of their drives and power systems.

[Pablo Sanchez]

Currently existing far IR detectors are sensitive enough to detect the heat from the NASA space shuttle's OMS engines at a distance of 20 light minutes. In other words, a sensor in Mars orbit could tell when one of the space shuttles was in Earth orbit.

With a 20 minute margin of error. But it's not as if that can be corrected.

[Knife]

No matter what era we are in the compitition between sensors, and sensor jamming or defeating systems will a concern for millitary forces. The same for sheilds and armour vs. weapons. Just have a balance between all of the above, and don't have a supper ubber weapon, shield, or system.