Newtonian Stealth

[Panopticon]

I think we are really looking at it too much from what is possible with our technology as it stands, as opposed to what might be able to happen in the setting of this game, if we can accept FTL and super-efficient power plants and so on made possible by completely made up elements, why is it such a stretch to imagine extremely powerful heat-sinks, or temperature non-conductive hulls, or shields that can hide your heat signature for a time?

I realize that that to have a sim that you can take seriously, we can't throw logic entirely out the window, but I imagine a happy medium could actually exist here without doing that.

[UnLimiTeD]

The made up materials are another thorn in my eye, I think we should reduce it to two or three kinds of handwavium and just abbreviate the rest, for example into "Metal", "Gas", "Rare Minerals" and "Fossil Fuels".
I suppose the correct assumption so far is that any possible Stealth is temporary, giving time to run away or attack first, but not a cloak that allows you to survey a system completely unseen for a month.
Because if we calculate with futuristic fantasy materials and possibilities, there's gotta be damn strong sensors on the other side.

[bean (OP)]

So, I read the entire page you linked, actually, I think I did in the past, so now I might have rushed a bit, I'm at work after all.
The difficulty here seems to be current Aurora systems.
In Aurora, detection is equal to being able to shoot at something; While efforts in stealth might only increase the time required for detection by a few hours, which could be helpful if you jump in at 10km/s with engines off, the main point I was trying to make is that it should be possible to mask your signature well enough that your opponent can't get a valid target lock, at least not before you.

Thank you.
However, that's not strictly true.  To shoot at something, you need an active sensor lock.  I do agree that more ambiguity in detection is good, but
if you're burning, there is no possibility of stealth outside of magic.

So far, in Aurora Sensors were used not to just detect that something is there, but what is there and if it's hostile.
With a realistic sensor system, we can expect to not an ID just from Thermal emission, neither will we get a target lock or a definite Thermal output strength of the object in question, and heat seeking missiles could be easily disposed of with buzzers if they don't know the exact Thermal signature they're looking for. Well, unless it's engine thrust from a known enemy.^^

Additionally, the text deals mostly with combat situations, for example that directing thermal emissions is unlikely to work because there could be sensors everywhere.
This requires both sides to know that combat is about to take place in that system; If you jump into a new system and encounter precursors that have been sleeping there for centuries, have no engines on, no life support, no active sensors, and you got no drones deployed, they gotta be pretty much invisible to your Fire Control, and ultimately, thats all that counts.

So while I fully agree that permanent stealth is impossible in space, the questions are: What exactly is "Stealth"? And wouldn't 2 hours be enough?

Why don't we expect to get an ID?  We can almost certainly tell who owns it at the very least, and how much waste heat it's radiating.  "Buzzers" are not going to be terribly effective unless they very closely mimic the target signature, probably on several bands.  It's rather hard to fool modern missiles.
As to the last two:
1. Stealth is being able to hide from opposing sensors while accomplishing your mission.  The act of being able to hide at some point is not enough in and of itself.
2. Only if your very^4 lucky.

The handwavium is the only possible mitigation, and while I'm not going to boycott the game if Steve leaves it in, I am going to argue that it shouldn't be there.

[jseah]

In realistic Aurora, yes, stealth is unlikely... passive sensors ranges should be increased more than 10 fold, possibly 100 or 1000 fold. 

It's not so much that sensor ranges should be increased but that the range calculation itself needs reworking. 

Black body radiation (thermal sensor) ought to be decreasing by the square of the distance.  And "radar" (active sensors) need to decrease by the fourth power of distance. 


As for decoys, I could envision a decoy drive that masks the true delta-v of the ship. 
Basically, it's a mass driver engine, not a normal drive.  Your reaction mass is cooled to cosmic microwave background and fired out at relativistic velocities, and it then breaks up.  If you can prevent some portions of it from heating up, then part of the delta-v obtained from the mass driver firing can't be detected and any estimates from the visible portions of the round will under estimate your delta-v. 

If you fire mini-engines out the back using a mass driver (which could be as simple as a conventional solid-fuel rocket), and they begin burning immediately after exit, then any movement readings of the engines-as-reaction-mass becomes completely unreliable as an estimate of what delta-v your ship gained. 

EDIT:
Following up with either some directional radiators (since your drive makes you hard to catch) or a heat sink, you can then make an approach that is incredibly hard to predict. 

[bean (OP)]

The first two paragraphs are correct.  The rest, not so much.
While a mass driver is theoretically much harder to detect then a plasma drive, it has several drawbacks.  The first is that it requires electricity, which means that the drive efficiency is less than 25% of the thermal output of the reactor.  The rest has to be dumped as heat.  Why?  Because reactors work best at 25% efficiency.  If you want more details, go to atomic rockets.  Second, the idea of putting a relativistic-velocity mass-driver on a ship is sort of problematic, as coilguns (which are basically mass drivers) are going to be quite long for even modest velocities, to say nothing of relativistic ones.  Third, the pulse rate on the mass drivers will have to be quite high (tens of hertz, at a guess), and it has to be maintained as long as the engines are running.  Fourth, they can still track you by the flare of your engines.  All that will result is an incorrect mass estimate.

I'm not sure what the second suggestion is.  Solid-fuel rocket exhaust looks almost nothing like a plasma drive, and shooting plasma drives rapidly gets expensive.
Directional radiators work against one enemy.  If they're included, listening posts (or ships) scattered around the perimeter of the system should make them ineffective.  The heat sink will have to be very large and very well insulated, particularly if you're using mass drivers.

[jseah]

All that will result is an incorrect mass estimate.

I'm not sure what the second suggestion is.  Solid-fuel rocket exhaust looks almost nothing like a plasma drive, and shooting plasma drives rapidly gets expensive.
Directional radiators work against one enemy.  If they're included, listening posts (or ships) scattered around the perimeter of the system should make them ineffective.  The heat sink will have to be very large and very well insulated, particularly if you're using mass drivers.

What I meant is shooting solid-fuel rockets as mass driver packets.  Their movement will conceal the delta-v the mass driver engine gives to your ship. 
The error in mass that the mass driver engine is meant to make is not intended to conceal your current position.  Firing a mass driver is likely to generate enough waste heat that you will have to vent.  However, incorrectly estimating the mass of the mass driver packet would create an error in the estimate of delta-v that your ship has gained. 
This makes all future calculations of your position inaccurate.  It also doesn't tell your enemies the mass of your ship. 

Your reactor doesn't have to be a thermal reactor though.  I imagine that such a reactor that outputs only electricity without a thermal cycle would be much more efficient.  But it does not really matter if you have a small enough reactor (or running at low power).  And a pretty darn huge heat sink and directional radiators. 
I imagine nearly the whole ship would be dedicated to the heat suppression device. 

The point about directed radiators being picked up by pickets is of course quite accurate.  However, if your radiator only radiates to say 10 degrees squared, one could force enemies to picket ships all over the place in order to find you.  (space is not flat, you can radiate out of the ecliptic)  The other thing is that they'll have to picket the points for long periods of time (to catch anything drifting into the system under zero power) and have to regularly cycle back for maintenance and crew rest. 

That said, I would think that any ship built to have a mass driver engine and dedicated most of its mass to a directional radiator is probably purpose built for something other than ship-to-ship combat. 
One idea: to make a suicide run against a planet.  It doesn't matter whether you even have weapons, a ship-sized object hitting the ground at high speed will likely ruin the planet as a colony destination for a long time, better still if your ship runs a nuclear reactor that then turns into an impromptu dirty bomb.  If its an enemy homeworld... XD

The simple threat of suicide directional-radiating ships would force an enemy to expend humongous amounts of fuel putting ships at station points outside the ecliptic (which costs the highest amount to get to), and do that for all major colonies (potential suicide run targets).  Even if all your ships get caught and destroyed, the logistics of conducting the attack is easier than preventing it.  You still win. 
And then if the enemies come in and blow up the pickets, your replacements won't get out there fast enough to catch any ships radiating into the hole before those ships arrive at their targets.  Or perhaps no such suicide ships were sent and they just wanted the morale effect of sitting around for a couple of weeks before the sensors are replaced, wondering if a metal rock is about to drop on your head. 

Of course, you still have to find crew willing to go on a one-way trip that will last months or years.  But then, one can always find fanatics. 

[jseah]

Second, the idea of putting a relativistic-velocity mass-driver on a ship is sort of problematic, as coilguns (which are basically mass drivers) are going to be quite long for even modest velocities, to say nothing of relativistic ones.  Third, the pulse rate on the mass drivers will have to be quite high (tens of hertz, at a guess), and it has to be maintained as long as the engines are running.  Fourth, they can still track you by the flare of your engines.  All that will result is an incorrect mass estimate.

Ok, I'll do this in detail. 

1st is handled above.  You can have an electricity only reactor that doesn't go through heat.  (batteries?  Chemical reactors?)

2nd.  Have you seen the railgun values given by Steve?  They shoot stuff at insanely high velocities.  It's feasible to use them as a drive if you shoot 1 ton projectiles. 
Maybe even 10 ton projectiles. 

3rd.  Your course corrections are done in bursts.  Generally, you fire one projectile (better have modular ones so you can scale your thrust accordingly) to get where you're going.  Or maybe you shoot a few.  But you certainly don't fire off a hundred. 

4th.  What engines?  The mass driver IS the engine. 

EDIT:
Thought of something. 

Could you not dump your heat into the projectile you just fired?  Sure, it'll make your projectile visible, but if there's no plasma plume, they won't know the mass of the projectile. 

If they don't know the mass, they don't know the momentum.  Bit hard to generate an intercept now. 

Scratch that, they can estimate the total heat in the projectile by observing its radiation drop over time.  Can probably get a specific heat capacity (ie. material type) and mass estimate that way. 

[bean (OP)]

What I meant is shooting solid-fuel rockets as mass driver packets.  Their movement will conceal the delta-v the mass driver engine gives to your ship. 
The error in mass that the mass driver engine is meant to make is not intended to conceal your current position.  Firing a mass driver is likely to generate enough waste heat that you will have to vent.  However, incorrectly estimating the mass of the mass driver packet would create an error in the estimate of delta-v that your ship has gained. 
This makes all future calculations of your position inaccurate.  It also doesn't tell your enemies the mass of your ship.

You still have me confused.  Just what, exactly, do these solid rockets do?  How do they make the enemy mis-estimate the delta-V? 
I do understand one thing.  I thought you were trying to conceal the mass driver within an exhaust plume, when it is the only engine.

Your reactor doesn't have to be a thermal reactor though.  I imagine that such a reactor that outputs only electricity without a thermal cycle would be much more efficient.  But it does not really matter if you have a small enough reactor (or running at low power).  And a pretty darn huge heat sink and directional radiators. 
I imagine nearly the whole ship would be dedicated to the heat suppression device. 

That is true, within limits.  The problem is reactor size.  Even at 75% efficiency, you still have a lot of waste heat to get rid of.  And leaking it out slowly is all well and good, but then your acceleration rate is pitiful to the point of absurdity.

Before we go any farther, I want one thing cleared up.  Is this an Aurora solution or a real-life one?  I can do either, but I need one or the other.  Bits of both can make it almost work, but you'll never see that.

[jseah]

In real life... you'll never get it to work. 

Aurora has powerful enough mass drivers and efficient enough reactors for this sort of scheme.  The problem of course is that you are getting real-life values of accelerations in an Aurora environment.  Journey lengths of months aren't exactly ideal when your enemy can make circuits of his system while you drift along.  (although that won't cut the number of anti-directional radiator pickets needed at all, since you can rotate a ship faster than a ship can go round.  Some way of representing the ability to radiate out of the plane is needed)
--- Actually, it might be possible since Aurora has tractor beams.  You can accelerate a ship to needed velocities, jump into an enemy system and detach the drive which goes back.  The bomb portion of the ship does needed course corrections with the mass driver (which could end up requiring mass packets of up to half the ship's mass; NOTE: When I say "nearly the whole ship will be the thermal suppression device", I mean, the part of the ship where heat gets generated.  Mass driver packets don't generate heat), then goes into full shutdown and drifts to collision with the target planet.  ---
EDIT: another idea would be a spy mission where the ship drifts past a planet and reads emissions from the space traffic and such things. 

Hence why I said the ships won't be used for ship-to-ship combat. 


The rockets make the enemy misestimate the delta-v by concealing the amount of heat and their original mass. 
Although I think perhaps the cooled projectiles idea is probably better.  This one can get rid of waste heat through the rockets but will get expensive really fast.  Not to mention that loading a large portion of your ship's mass with highly combustible solid fuel is not going to be a good idea. 

[jseah]

Come to think of it, could you not make computers run such a ship?

Computers would run the glorified missile just as effectively as people and able to do that at very much lower temperatures (especially if you have a non-nuclear power source), allowing you to save massively on the heat suppression device and thus be smaller. 
Simply dumping your heat early on would let you drift while at just above cosmic microwave background.  Effectively undetectable. 

You can always dump your drive (with all the heat on it) once you got to your speed.  And then jink a little with a mass driver to confuse prediction of the future location before essentially halting all functions. 

[bean (OP)]

That said, I would think that any ship built to have a mass driver engine and dedicated most of its mass to a directional radiator is probably purpose built for something other than ship-to-ship combat. 
One idea: to make a suicide run against a planet.  It doesn't matter whether you even have weapons, a ship-sized object hitting the ground at high speed will likely ruin the planet as a colony destination for a long time, better still if your ship runs a nuclear reactor that then turns into an impromptu dirty bomb.  If its an enemy homeworld... XD

The simple threat of suicide directional-radiating ships would force an enemy to expend humongous amounts of fuel putting ships at station points outside the ecliptic (which costs the highest amount to get to), and do that for all major colonies (potential suicide run targets).  Even if all your ships get caught and destroyed, the logistics of conducting the attack is easier than preventing it.  You still win. 
And then if the enemies come in and blow up the pickets, your replacements won't get out there fast enough to catch any ships radiating into the hole before those ships arrive at their targets.  Or perhaps no such suicide ships were sent and they just wanted the morale effect of sitting around for a couple of weeks before the sensors are replaced, wondering if a metal rock is about to drop on your head. 

Of course, you still have to find crew willing to go on a one-way trip that will last months or years.  But then, one can always find fanatics. 

This is exactly the sort of Rube Goldbergian solution proposed by advocates of space stealth.  Yes, you can, theoretically, under ideal circumstances and your set of assumptions, probably make it work.  That's not the question.  The question is, can it do the job better than another solution.  That is the standard by which these sort of things must be judged.
First, the idea of using a ship as a weapon against a planet is just plain silly.  Have you never heard of missiles?  They're a lot easier to stealth as they don't have a crew that has to be kept 285K above background.  (And I do know that electronics don't work well at 3K.  However, a small pile of chips at, say 270K, is going to produce a lot less heat then any reasonable crew.  And don't bring aliens from a supercold planet as a rebutal.  That's just pleading.)  They also don't require you to find fanatics, and to feed them and supply them for a couple years.  
Actually, most strategic kinetic strikes are silly.  Nukes work better.
Second, the entire scenario requires an open-space FTL drive that leaves no jump signature whatsoever.  Wormholes, jump points, and the like are out, as those can and will be tightly picketed.  The same goes for any in-system colonies of significant size.  The jump in must also leave no signature.  (And don't bring up Oyster Bay.  Weber engineered that into the FTL system, and there was revolutionary new tech involved.  It only can happen once.)  These assumption can be (and have been) made, but I find them questionable at best, and pleading at worst.
Third, why do you have to send manned ships to points above and below the ecliptic?  If this is Aurora, there is no ecliptic, so you can't radiate into it.  If it's real life, they'll going to use robots instead.  And they don't have to be fancy ones.  It's an IR camera with an attitude control system and a computer.  You have to know where all of them are for this to work, and they're a lot stealthier than your ship.  They're also disposable.
Fourth, you're in a Red Queen's Race between multiple methods of detection.  With a small reactor and a big heat sink, the acceleration is slow (particularly in Aurora terms) and it will take you literally years to get up to a reasonable speed.  And by reasonable, I mean "damage comparable to asteroid impact" not "capable of Hohmann transfers".  And that gives the other guy more time to spot you, through star eclipse, reflection, someone coming close, or a sensor probe wandering into the beam.  With a big reactor, the acceleration is higher, but so is the detectability.  The cameras just got a lot cheaper, which means I can have more.
Fifth, your math is bad.  Stealth does not equal win.  You haven't mentioned how it's going to get though the defenses around the target planet.  Radar stealth is not a feature of this design, and assuming I'm competent and you're attacking a major planet (incompetence requires pleading, and this is entirely too expensive for a minor colony) the ship will be detected weeks out.  That leaves a slow, underdefended hunk of metal at his mercy.  And I doubt he'll have any.
Sixth and last, you seem to be contradicting yourself.  First, you said it would cause him to miscalculate your position.  This is not the same as being invisible.  Yes, his math may be a few percent off, but that's not going to make him think that you're a harmless trader going in the other direction.  And you've also just announced to the world that you're using a stealth drive.  And that is going to bring warships with active sensors, and a very low tolerance for your presence.
What's the alternative?  A fleet with missiles with nuclear warheads.  Or, if you're dead set on this design, dump out passive nukes and leave.  It's easier and more effective.

I apologize if I rambled on there.  I rather strongly dislike this kind of thing, and decided to finish it off now.  There are other problems, and I'll raise them if needed, but I hope this has settled it.
Second note, I wrote this before the previous two posts were posted.  A lot of improvements were made, but not all of my points were addressed (and I'm feeling lazy) so I'll post it as-is.

[bean (OP)]

In real life... you'll never get it to work. 

Aurora has powerful enough mass drivers and efficient enough reactors for this sort of scheme.  The problem of course is that you are getting real-life values of accelerations in an Aurora environment.  Journey lengths of months aren't exactly ideal when your enemy can make circuits of his system while you drift along.  (although that won't cut the number of anti-directional radiator pickets needed at all, since you can rotate a ship faster than a ship can go round.  Some way of representing the ability to radiate out of the plane is needed)
--- Actually, it might be possible since Aurora has tractor beams.  You can accelerate a ship to needed velocities, jump into an enemy system and detach the drive which goes back.  The bomb portion of the ship does needed course corrections with the mass driver (which could end up requiring mass packets of up to half the ship's mass; NOTE: When I say "nearly the whole ship will be the thermal suppression device", I mean, the part of the ship where heat gets generated.  Mass driver packets don't generate heat), then goes into full shutdown and drifts to collision with the target planet.  ---
EDIT: another idea would be a spy mission where the ship drifts past a planet and reads emissions from the space traffic and such things. 

Hence why I said the ships won't be used for ship-to-ship combat. 

Very good.  You worked out for yourself what was wrong with your scheme.
1. Doing it, even in Aurora, produces very low accelerations.  I'd estimate at the very high end, 1 km/s/day.
2. Towing something in and letting it coast (or coming out of FTL completely silent) is a lot easier, though I would prefer to do it with a civilian ship as cover.
3. Electronics are far better than humans for this.

The only thing you missed was replacing rocks with nukes.

The rockets make the enemy misestimate the delta-v by concealing the amount of heat and their original mass. 
Although I think perhaps the cooled projectiles idea is probably better.  This one can get rid of waste heat through the rockets but will get expensive really fast.  Not to mention that loading a large portion of your ship's mass with highly combustible solid fuel is not going to be a good idea. 

The rockets undo the entire system.  The rocks are going out fairly cold compared to most exhaust (I do expect some heating from the mass driver) but then you light the rockets, announcing to the entire system where you are.  And that you're using a drive that makes no sense at all for anyone other than someone trying to stealth a ship.  Warships will come to investigate.

[jseah]

That is true though.  A computer run probe could do this run much better than a crewed ship. 

But then, after some examination, I was approaching the conclusion that anything not a commercial ship is probably better computer run.  Stealth or no. 

The weight saved in life support alone already makes it alot better.  Goodness knows I went to insane lengths to save another 50 tons for my ships in 5.20.  And in Newtonian Aurora, mass is going to matter even more. 


Although your comment about in-system transit times probably won't apply to Newtonian Aurora.  You can always use normal engines to get incredibly high speeds and simply jump to your target system with whatever speed you need.  I would say it could even make relativistic missiles possible.  (although there is no point in Aurora since nukes are super-effective and the advantage of relativistic missiles is that you can't see where they are since you can't get the information in time.  Aurora having FTL sensors kinda kills that. 

Then again, you can get much higher yield per ton with relativistic rocks than nukes. 
EDIT: also that kilo-ton range "missiles" do more damage than a nuke.  It's like a small asteroid impact.)

Radar absorption is already present in original Aurora though.  The original "cloaking device" only works on actives and makes the mounting ship appear much smaller.  Which could end up (with alot of RP investment) with kiloton range ships that need an anti-missile sensor to find.  (bigger resolution sensors don't even generate a contact)
-- Also to note that covering a system with anti-missile level of active sensor coverage is basically impossible

Hopefully, by the time they spot your "stealth" missile with high-res sensors on the planet, it'll be too late to try shooting it down.  Especially in Newtonian Aurora where missile flight times have increased alot. 

The point is to hope to conceal what your current position and velocity is so that even if they try looking, they'll have to scan large portions of the system before they can find you.  They know where you *were*, but can't tell how fast you were going. 
EDIT: if you were aiming at a planet, and they knew that, then they'ld have to scan a cone leading from your current position to plausible intersections with the orbit of the planet.  That's too much to scan even with Aurora active sensors.  At least if they need anti-missile resolution.  Anti-ship resolutions can scan out to Mars orbit pretty easily. 

1. Doing it, even in Aurora, produces very low accelerations.  I'd estimate at the very high end, 1 km/s/day.

Nope.  The 2.4GJ example railgun fires a 1ton shell with a momentum of 2 ton km/s.  It also looks like a low tech railgun. 

The way it looks like is that multiple small railguns would the way to go in designing a railgun-drive. 

They're still better than the drives we have in RL. 

[UnLimiTeD]

This is sure a busy thread.
So far, what I can see is that the discussion shifted from trying to hide a ship to concealing a projectiles position long enough to prevent it from being intercepted?

[jseah]

Yup. 

Also note to self:
When newtonian aurora comes out, I need to try "breaking" light speed.  XD

Megaproject - accelerate something, anything, past light speed.