[Aardwolf]

Srsly guys, stop with the quote warfare.

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Ok uh... would a setup such as the following work?

1. An observer (could be sensor drones, or ships, or whatever) detect an enemy ship.

2. Regardless of whether the observer has been detected by the enemy, the observer then transmits to a friendly control center (ship or station where data is collected), which preferably is and will remain undetected by the enemy. If the observer matters (that is, you can't afford to lose it), then this transmission can be done via laser. If you don't give a damn what happens to the observer after it transmits, then you might as well just do an omnidirectional squawk. Or maybe it uses some sort of "hand gesture" system, readable from any direction but only if you've already got your telescope trained on the observer. Either way, the control center is still safe.

3. Now the control center knows where the enemy is. It can track the enemy as well as the observer, if not better (because it's designed to). It now begins tracking the enemy contact. The observer may now go on with it's business.

Note that the observer is not necessarily a 'focused' detection device like a telescope. It may be capable of focusing in on something like a telescope does, and it may do that whenever it spots a new contact, though.

The control center, on the other hand, is like a whole bunch of independent telescopes (or some similar sort of device(s)), which upon hearing about something, will point themselves at that something and not let it out of sight. Only one telescope (out of all of those on a control center) needs to be assigned to any one contact, except possibly as the contact moves out of view of one and into view of another. If there are multiple such control centers (which is probably a good idea), they can share some of their targeting data with each other (provided they can use some of the previously discussed "low profile" communication methods), so that if one goes down, the rest of them are still able to track (most of) its targets.

As for actually doing the attacking, the weapons platforms (lasers, missile pods, etc.) could and probably should be separate from the control centers. That way, you can attack without risking the loss of any more than that single platform.

Distributed and redundant systems FTW... then again, you probably won't trust an army of tiny robots to declare war or negotiate peace, so you still need to have some way of telling them what to do. Maybe just a failsafe, so if they're still floating around 10 years after the last friendly contact, they self destruct.

[Colonol Dekker]

NooOOOo do it so that if they ARE still floating around ten years without friendly contact, they must activate scorched earth protocol and avenge <strikethrough>me</strikethrough> their human masters.

[perihelion]

Why does the deployed sensor net need to be a "daisy chain" at all?  Why not more like a neural network?  Multiple paths back to the "home" ship.  All communication could still be tight-beam to prevent detection.  Active communication between nodes in the net to keep all elements apprised of position.  I see minimal chance of the communication being detected.  How likely is it for the enemy to fly right through a tight-beam in order to intercept the transmission?  Even so, with sufficient encryption, the enemy still only knows the location of two elements of the net, and does not know whether they are merely sensor buoys or weapons platforms etc.

To me, it seems like redundancy is the best defense and offense.

[Flaser]

Meh, I'm tired of people regurgitating their "WW II U-boat/1990 Desert Strom in Space!" arguments again and again. Here are the facts:

1. Any object that is fast enough to evade a laser (even with light speed lag) will be detected.

2. Any object warm enough to house humans will be detected.

3. Jamming is useless. In space you don't need active detection as there is no atmosphere to degrade passive detection. Jamming can only effect active, ie. radar detection, but it just makes the life easier for your foe if they use passive detection.

4. Small stationary, really cold objects could be harder to detect - until they fire, then they light up like a Christmas tree. Thermodynamics says so. Any weapon that can hurt a ship will output enough waste heat so you show up.

5. ...to not light up, you'll need a *big* heat sink. Like an asteroid that will be detected anyway. Unless you're doing battle in the rings of Saturn that will be conspicuous anyway.

6. ...so all your transmission schemes are irrelevant as a maneuvering enemy can bypass your comm-net just by putting on a few km/s. You headquarter will show up anyway and will need to dodge either lasers of missiles if you're further back so you might as well put in on a warship that can dodge good.

So the final werdict:

Stealth is useless.

Stop trying to justify it, when you've yet to write a single equation. It's been done a thousands times and it has been proven *not* to work a million times.

[Aardwolf]

1. You don't have to evade if they don't know you're there, and they'll only know you're there once you start firing. By then it's too late.

2. You don't have to have humans to be dangerous.

3. That would only make sense if the jamming device is on the ship that's trying to hide. Obviously the jamming device is not going to be following along with the ship, it's going to be jettisoned as a decoy. Otherwise it's like trying to distract a guard dog by yelling "fetch the juicy steak" and then tucking the steak into your trousers and walking away.

4. By then it's too late. And maybe it's a one-use weapons platform anyway, so not only did they lose whatever I shot, but they also wasted a shot.

5. Or I can use unmanned throw-away vessels that aren't producing heat until they're firing anyway, and by then it's too late.

6. What? Bypass my comm-net? This makes no sense.

Stealth: Who's talking about stealth? Nobody here is talking about stealth except you.

Even if you can't be "stealthy", unless they've spotted your little blip on the infrared, and are actively tracking you, they've got a whole sky to search through. It doesn't matter that your thrusters are visible from Pluto if nobody's zoomed in watching that region of the sky in infrared. Just as a baseball field on earth can take a while to find in Google Earth, so too can a spacecraft evade detection in space. No "stealth" is required.

We've all (well, maybe 'all' is a bit too optimistic, but whatever) been aware of the effective impossibility of "stealthy" manned/armed/self-propelled spacecraft since before I posted this. The issue, if you had read the first post, revolves around the fact that once they notice you and start tracking you, there's very little you can do to get them to un-notice you.

Edited to fix 1 or more typos.

[Flaser]

Finding you is a *trivial* matter unless you do your damnest to hide your emissions. You people *still* don't realize that you're talking about fantasy scenarios from space-opera while the rest of us try to quote hard facts.

For God's sake stop spouting more of the same nonsense and read some solid science!

http://www.projectrho.com/rocket/rocket3w.html
http://www.rocketpunk-manifesto.com/2009/06/space-warfare-ii-stealth-reconsidered.html

Ken Burnside said:
Most of the arguments on thermo and space detection run through a predictable course of responses:
1) "Space is dark. You're nuts!"
2) "OK, there's no horizon, but the signatures can't be that bright?"
3) "OK, the drive is that bright, but what if it's off?"
4) "But it's not possible to scan the entire sky quickly!"
5) "OK, so the reactors are that bright, what if you direct them somewhere else..."
6) "What if I build a sunshade?"
7) "OK, so if I can't avoid being detected by thermal output, I'll make decoys..."
8) "Arrgh. You guys suck all the fun out of life! It's a GAME, dammit!"

Ken Burnside said:

A full spherical sky search is 41,000 square degrees. A wide angle lens will cover about 100 square degrees (a typical SLR personal camera is about 1 square degree); you'll want overlap, so call it 480 exposures for a full sky search, with each exposure taking about 350 megapixels.

Estimated exposure time is about 30 seconds per 100 square degrees of sky looking for a magnitude 12 object (which is roughly what the drive I spec'd out earlier would be). So, 480 / 2 is 240 minutes, or about 4 HOURS for a complete sky survey. This will require signal processing of about 150 gigapizels per two hours, and take a terabyte of storage per sweep.

That sounds like a lot, but...

Assuming 1280x1024 resolution, playing an MMO at 60 frames per second...78,643,200 = 78 megapixels per second. Multiply by 14400 seconds for 4 hours, and you're in the realm of 1 terapixel per sky sweep Now, digital image comparison is in some ways harder, some ways easier than a 3-D gaming environment. We'll say it's about 8x as difficult - that means playing World of Warcraft on a gaming system for four hours is about comparable to 75 gigapixels of full sky search. So not quite current hardware, but probably a computer generation (2 years) away. Making it radiation hardened to work in space, and built to government procurement specs, maybe 8-10 years away.

I can buy terabyte hard drive arrays now.

I can reduce scan time by adding more sensors, but my choke point becomes data processing. On the other hand, it's not unreasonable to assume that the data processing equipment will get significantly better at about the same rate that gaming PCs get significantly better.

Now, this system has limits - it'll have trouble picking up a target within about 2 degrees of the sun without an occlusion filter, and even with one, it'll take extra time for those exposures.

It won't positively identify a target - it'll just give brightness and temperature and the fact that it's something radiating like a star that moves relative to the background.

On the other hand, at the thrusts given above, it'll take somewhere around 2 days of thrust to generate the delta v to move from Earth to Mars, and the ship will be in transit for about 1-4 months depending on planetary positions.

Nyrath wrote:

The maximum range a ship running silent with engines shut down can be detected with current technology is:

Rd = 13.4 * sqrt(A) * T^2

where:

Rd = detection range (km)
A = spacecraft projected area (m^2 )
T = surface temperature (Kelvin, room temperature is about 285-290 K)

If the ship is a convex shape, its projected area will be roughly one quarter of its surface area.

Example: A Russian Oscar submarine is a cylinder 154 meters long and has a beam of 18 meters, which would be a good ballpark estimate of the size of an interplanetary warship. If it was nose on to you the surface area would be 250 square meters. If it was broadside the surface area would be approximately 2770. So on average the projected area would be 1510 square meters ([250 + 2770] / 2).

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. If the crew had a more comfortable room temperature, the Oscar could be seen from even farther away.

[Aardwolf]

I am familiar with projectrho. Stop assuming that, because you know such misconceptions exist, the people disagreeing with you must have them.

[Wanderer]

So... summarizing...

It seems likely that a properly designed 'stealth' ship - remote or mostly remote controlled heavily insulated rock covered coasting thingamajig - would be able to approach far closer to the sensor site than regular ship. And deliver a barrage before being detected - with c lag it might be able to shoot several times before being spotted. But after the initial barrage there wouldn't really be any place for it to hide or shake the 'sensor lock' apart from going behind some bigger object.

[Flaser]

So... summarizing...

It seems likely that a properly designed 'stealth' ship - remote or mostly remote controlled heavily insulated rock covered coasting thingamajig - would be able to approach far closer to the sensor site than regular ship. And deliver a barrage before being detected - with c lag it might be able to shoot several times before being spotted. But after the initial barrage there wouldn't really be any place for it to hide or shake the 'sensor lock' apart from going behind some bigger object.

Even the first doesn't happen: to move into position it'd need to use an engine of some sort and then it'd be picked up.
...or it'd need to coast into position, however unless you can plan your engagement to happen months in advance that won't happen.

I'll grant you this: you might hide rockets or a laser or two on asteroids around a planet. However there's just so goddamn much space to cover that's it's unlikely that your emplacements would be in position to shoot. Furthermore anyone coming in may drop kinetic killers on all orbital emplacement as a policy as they too would be aware that you can hide nasty surprises on rocks.

[Aardwolf]

Lasers don't need to close the distance

[Wanderer]

...remote or mostly remote controlled heavily insulated rock covered coasting thingamajig...

Even the first doesn't happen: to move into position it'd need to use an engine of some sort and then it'd be picked up.
...or it'd need to coast into position, however unless you can plan your engagement to happen months in advance that won't happen.

I did not say it would easy or very practical. Just that it should be possible within certain extent.

Also the all glorified RKV theory is flawed as it assumes that all warfare would total warfare in nature. Unrestricted by any laws or sanity. Same issue which governs the use of NBC weapons most likely affects RKVs as well. No one wants to conquer a nuclear or chemical wasteland or contaminated landscape. Same issue with RKVs... Impressive in theory but i doubt any sane strategic goal would include a step which renders the target planet uninhabitable.

The way i see the it...
Not big or fast enough RKV and it can be most likely shot or detonated to bits or diverted as case might be. Big and fast enough RKV to be able to ignore these threats and there is no longer any point launching it if you intended to actually land on the target planet within your lifetime. But that is already off-the-topic.

[General Battuta]

...remote or mostly remote controlled heavily insulated rock covered coasting thingamajig...

Even the first doesn't happen: to move into position it'd need to use an engine of some sort and then it'd be picked up.
...or it'd need to coast into position, however unless you can plan your engagement to happen months in advance that won't happen.

I did not say it would easy or very practical. Just that it should be possible within certain extent.

Also the all glorified RKV theory is flawed as it assumes that all warfare would total warfare in nature. Unrestricted by any laws or sanity. Same issue which governs the use of NBC weapons most likely affects RKVs as well. No one wants to conquer a nuclear or chemical wasteland or contaminated landscape. Same issue with RKVs... Impressive in theory but i doubt any sane strategic goal would include a step which renders the target planet uninhabitable.

They'd work like nukes - deterrents.

[Flaser]

Lasers don't need to close the distance

They do. Their effective range is limited by diffraction.

[Aardwolf]

Well yeah, but unless you're a couple AU away, you're still dead.

[BengalTiger]

Ken Burnside said:

A full spherical sky search is 41,000 square degrees. A wide angle lens will cover about 100 square degrees (a typical SLR personal camera is about 1 square degree); you'll want overlap, so call it 480 exposures for a full sky search, with each exposure taking about 350 megapixels.

That gives 3.5 MPi per square degree, or 1871 lines per degree. This means each line is 2 seconds of angle wide, and a pixel is 2 sec by 2 sec. Wikipedia says the Moon is about 30 arcminutes in angular diameter, and it's 3474 km across.
So in this scan, the Moon fits into a square that's 900x900 pixels, giving almost 4 km per line and 16 km^2 per pixel. If we parked the SJ Sathanas on lunar orbit facing Earth, it's 2.6 km by 2.8 visible part would have a surface of 7.3 km^2. That's less than half a pixel.
The camera will average out the temperature on the whole area the pixel covers. Let's assume that the ship has 280 K inside and absolutely no thermal insulation (giving it the 280 K on the outside as well).
If you're lucky, it'll be in a single pixel, and you'll get 7.3 km^2 with 280 K, and 8.7 km^2 with 3 K. The pixel will have a brightness of (7.3*280+8.7*3)/16= 129.4 K.
If you're unlucky, and the ship spreads out evenly on 4 pixels, it'll be a pretty cold object, with the 4 pixels at some 30-something K.

If you're very unlucky, and the ship has thermal insulation, and it's outside is hundreds of degrees colder than the inside (like a re-entering Space Shuttle, only inverted), it'll get below 10K.
Now if your ship isn't a Sath, but a GTF Pegasus facing the Earth.....

Nyrath wrote:

The maximum range a ship running silent with engines shut down can be detected with current technology is:

Rd = 13.4 * sqrt(A) * T^2

where:

Rd = detection range (km)
A = spacecraft projected area (m^2 )
T = surface temperature (Kelvin, room temperature is about 285-290 K)

If the ship is a convex shape, its projected area will be roughly one quarter of its surface area.

Example: A Russian Oscar submarine is a cylinder 154 meters long and has a beam of 18 meters, which would be a good ballpark estimate of the size of an interplanetary warship. If it was nose on to you the surface area would be 250 square meters. If it was broadside the surface area would be approximately 2770. So on average the projected area would be 1510 square meters ([250 + 2770] / 2).

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. If the crew had a more comfortable room temperature, the Oscar could be seen from even farther away.

Again, they assume the outside temperature will be the same as inside. Can anyone calculate how much power the ship would be emitting through thermal radiation if it had a sustained 280 K on the outside, in a 3 K environment?
Can anyone calculate how much energy an idling (running on full power) nuke reactor and 200 crewmen generate? We'd be able to figure out once and for all how warm the outside will have to be to radiate the surplus heat.

BTW- this time they're looking for it far more closely than doing a quick 4 hour scan of the sky with a 100 square degree camera described above.

[Aardwolf]

Thank you, BengalTiger, for doing that math for us. This was something I was thinking about from early on in this discussion (but didn't have any concrete figures for); even if a full-sky search takes however long, the resolution for that is limited. To get anything useful, you'd need to do a much narrower scan of the area around the little anomalous blip (your < 1-pixel-sized Sathanas, in the example).

[redsniper]

Or just use higher resolution cameras (or sensors or whatever). Which I'm sure we'll have by the time we start having serious space wars.

[Aardwolf]

Higher resolution requires more processing power (or more time to process). Obviously.

[redsniper]

Oh damn, too bad advancements in computer processing power have come to a stone cold stop. Oh wait, they haven't.

[Scotty]

OP specified no technical level of computational ability.  I'd say it's a fallacy to assume best-case scenario in that department for the purposes of this exercise.