Superconductors, Stealth vs. ECM/ECCM in Space

[Sky Captain]

Ion and even more photon drives have very small thrust. IIRC photon drive produces only 1 Newton of thrust per 300 MW of power. Warship with multi gigawatt reactor would only get few dozens of Newtons worth of thrust at most while producing huge amount of waste heat and running through it`s nuclear fuel reserves at alarming rate. Such ship would probably weigh tens of thousands of tons which means it would take forever to reach any reasonable velocity.

Although much more power efficient ion drives still have small thrust. There is also some rather hard limit how much thrust can be achieved from ion drive before electric fields get so intense arcing occurs.

For spacecraft expected to see combat I would want it to be capable of 2 - 4 G acceleration to be able to dodge incoming fire and quickly respond to changes in tactical situation which would be far more valuable capabilities than small chance of being more difficult to detect.

Carrying two sets of engines one for low power semi stealthy departure and one for combat maneuvering means lots of mass wasted on what could be more missiles more point defense turrets and more propellant.

Anyway even for a ship running silent I would see opponent expecting an attack and actively monitoring the skies to be able to detect it well before that ship gets into effective weapon range thus making the whole stealth thing more liability than advantage.

[Admiral Valdemar]

Well that's the thing. You've gimped your own ship with this useless notion you can somehow sneak up to attack range in space, while the enemy can manoeuvre at will and deploy active sensors that will notice a huge shield and radiator assembly easy enough. By which point, the attacking ship will either detect it was found via a radar sweep and be forced to give up the sneak attack and engage, or the attacker is oblivious. Why would anyone be afraid of a quiet space station? So long as you're going stealthy, you're going nowhere fast and you're not a concern at all.

EDIT: I should have put "waste energy" not "heat" in my prior post regarding ion drives.

[Ender]

Or that a photon drive lighting up a trail of interplanetary dust leading straight back to your ship is somehow a stealthy idea.

Interstellar dust is so ridiculously sparse (on the order of a few atoms per cubic metre) that the radiation is literally undetectable. I confess I don't know the average density within a solar system, but I'd be surprised if it was opaque enough to detect the backscatter from even a terawatt laser from significant distances. If you think this is detectable please prove it.

AV covered most of this, but I wanted to touch here because I brought it up as well - while the ISM is very light, the radiation is far from undetectable In fact we do quite a bit of astronomy on it, studying stars, active stellar corpses, quasars, and radio galaxies by it. The scale of power is quite reduced, but so is the proximity. Carving radio plumes in the surrounding medium will give away a ship to local observers.

[Darth Wong]

Question: just how close do you guys think the attacking vessel has to get? It seems to me that you're still stuck in Star Trek mode, as if the attacker has to get close enough to spit on the target. If it's so close that you can view its physical appearance in detail with a telescope, it's close enough for it to nail you with a laser.

There's three variables in play to determine this. First is beam dispersion (only applies to directed energy weapons). This is a frequency dependent attribute, so grasers will have better values than masers. However, actually generating a graser beam is difficult. Best is likely x-ray (we do know how to make x-ray lasers). Of course, there's the flipside to this of penetration. Some is good. Too much is bad, because you won't deposit enough energy in any one place to cause a kill. Particle beams must be electrically neutral to have a good beam dispersion.

The second is lag. Your shots are no longer going where the enemy was. Best you can get is mere light speed. It gets a bit worse for particle beams, and is the worst with mass drivers. However, mass drivers do have an advantage in this: the rounds can be guided, which can help beat lag. However, see variable 3.

The last is point defense. The better the point defense, the lower the range you can use a guided weapon. On the other hand, at the point where we're most likely at, detection and tracking of missiles is probably close to perfect. At which point the best you can hope for is to overload the point defense. This is essentially range independent.

In any case, you're likely to start firing in the light second range. It keeps the lag down to manageable levels. However, this still depends on how maneuverable the opposition is (the more maneuverable, the better able they are to use lag to keep from getting hit).

I think we need to remember, however, that the kind of big sensor platforms we're talking about are going to have pretty predictable flight paths. You don't need to restrict yourself to a 1-second lag in order to nail it with a laser, and a sensor platform isn't going to be particularly durable.

[Admiral Valdemar]

I think we need to remember, however, that the kind of big sensor platforms we're talking about are going to have pretty predictable flight paths. You don't need to restrict yourself to a 1-second lag in order to nail it with a laser, and a sensor platform isn't going to be particularly durable.

Not necessarily. The Keck telescope has a 10 metre diameter lens that can resolve a space shuttle launch (under 40 GW) at around 3.5 AU. A smart defender would employ multiples of these units on the cheap in orbital patterns around space under their control. They can be autonomous and look out for any IR or visible signatures that defy the already mapped major bodies of the local space sector. As soon as such an observer platform detects a potential exhaust plume or thermal signature, it can power up its transceiver and contact the nearest friendly vessel and direct it for an intercept course using track-while-scan modes. Such detectors would be far and away easier to hide than a multi-kilotonne ship, not to mention cheaper, and allow the defender to have a very large window in which to prepare for the enemy attack. They could dictate when and where to engage, as the enemy attacker goes on assuming it has gone undetected, while the enemy uses its superior mobility sending either manned vessels, or "combat wasps" flying a 40 gee burn towards the enemy packed with munitions.

These sensors could be mounted on the ships themselves with ease too, and with advances in sensitivity and cyrogenic cooling and AI acquisition, could be used to devastating effect. Multiple fish eye lensed variants could act as passive initial target acquiring platforms, which then surrender control to dedicated, point base telescopes tracking the target and active sweeps using radar or NPBs to probe and derive the mass of the target ship, could also be employed.

[TheLostVikings]

and not the fact that the machinery powering the basic ship systems will be producing tremendous heat,

That can be managed with heat sinks, screening mass and directional heat dumps. It is quite possible to have a plate covering the front of your ship chilled to liquid helium temperatures if the back side is covered in radiators, and this could still be tactically valuable if you know the (general) location of the enemy sensors.

And if the enemy does the same thing to his sensors, only pointing the heat sinks in random directions, you can NEVER know where it is safe to point YOUR heat sink.

There is no stealth in space... The end.

You can't avoid the thermodynamic side-effects here without just not producing the energy in the first place.

You are assuming passive thermal management when a realistic spacecraft is anything but.

You are assuming that the enemy cant do exactly the same as you do. And we all know what happens when you assume.

[Formless]

And if the enemy does the same thing to his sensors, only pointing the heat sinks in random directions, you can NEVER know where it is safe to point YOUR heat sink.

There is no stealth in space... The end.

So, wait, are you saying that because this particular form of stealth in space can work for one person, it can work for his enemies as well, and is thus self defeating? Did I read that right? Because I'm thinking "duh".

[Admiral Valdemar]

It can't work, period. Assuming the enemy is sitting there, always facing you and never moving is the height of stupidity. You can funnel radiation directly behind you, but if the enemy is actually not totally incompetent and employs the cheap, hard to detect sensor platforms I proposed before, then you're going to look like a freakin' signal flare to anyone who's looking in the right direction.

We'll ignore that the enemy will have seen you long before you employ this tactic anyway as you use your boost phase to get into position for a coast to the target.

[Formless]

Well, to elaborate, I meant that whenever one side has a technology that grants an advantage, whenever the other side get access to the same technology, the overall advantage of having that technology diminishes anyway. If the defending side needs our flawed little stealth scheme to ensure that their sensor platforms don't get shot down en rout, then it is still the one technology defeating itself.

Granted, unless you have the massively impractical photon or ion drive (or maybe even a solar sail, I'm not sure if they give off the kind of radiation that foils stealth-- unless you are counting on seeing the reflecting glare of the sail) the exhaust plume will likely be the end of you.

[Admiral Valdemar]

By all means shoot the sensor platforms. You'd be doing the defending side's job for them. But yes, the whole scheme is very silly and restricts the attacker for little to no actual gain.

[Ender]

These sensors could be mounted on the ships themselves with ease too, and with advances in sensitivity and cyrogenic cooling and AI acquisition, could be used to devastating effect. Multiple fish eye lensed variants could act as passive initial target acquiring platforms, which then surrender control to dedicated, point base telescopes tracking the target and active sweeps using radar or NPBs to probe and derive the mass of the target ship, could also be employed.

I would have thought LIDAR in addition to the Radar myself. What do you plan on using the NPBs for? Of the top of my head I can't think of any sensor returns they provide that are 1) needed by a warship and 2) aren't matched by other systems, so I'm curious as to what I'm missing.

[Admiral Valdemar]

NPBs can be a weapon system too. You can use them to get a better tag on the mass and composition of the target as an addition to other sensor readings. It's just a nice added effect, but primarily it's a weapon system.

[Ender]

NPBs can be a weapon system too. You can use them to get a better tag on the mass and composition of the target as an addition to other sensor readings. It's just a nice added effect, but primarily it's a weapon system.

Ah, I thought we were talking sensors still, rather than full suite. My mistake. Yeah, blowing off a bit of the target and doing spectroscopy on the debris cloud is a decent way to get information. Extremely hostile, but it is still a decent way.

[Admiral Valdemar]

Hey, if they're a rock, then they can't complain. If they're stealthy military men, then they have some 'splainin' to do.