Space Warfare II - Stealth Reconsidered

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Stealth in space is possible, but only under certain special conditions.

 

There are a couple of assumptions being made that result in the false idea that stealth in space is impossible. These same assumptions are made in the excellent Atomic Rocket web site.

 

The first assumption is that space is empty. It isn't. It's mostly empty. But mostly empty is infinitely more crowded than completely empty.

 

The second assumption is that the only hot object in an otherwise bitterly cold universe is your spaceship. This is also not true. Every object in a solar system is various shades of hot.

 

So the issue isn't one of "my ship shows up like a beacon because it's hotter than space in an infinitely empty universe therefore there is no stealth," but rather: my ship is a teeny-tiny speck that may or may not be hotter than other teeny tiny specks in the area.

 

First, dealing with the space is only mostly empty issue. Your detection system is going to have to have a complete, continually updated database with EVERY object in your solar system, and I mean every object. That means stuff in the oort cloud, too, so if a comet gets nudged, you can spot it instantly and send someone out to find out if it's a natural object or something more sinister. Remember those cometary fragments are hotter than background space, too, and their IR could be a ship rigged for silent running.

 

This is a major investment in time and resources, which means only highly strategic or important systems are going to have that kind of detection infrastructure. Border systems and less important worlds aren't going to have it. That allows us stealth using the other false assumption: that your ship is the only hot object in the universe.

 

The key, here, is to make your ship no hotter than any other object in thermal equilibrium at a similar distance from the sun. That's going to prevent you from firing up your main drive with its gigawatts or more of plume heat, but it will mask your normal ship operations, so, no, your crew doesn't have to shiver in the dark. The asteroid Eros has a dayside temperature of 373 Kelvins, way toastier than your ship crew needs to be comfortable and way, way, way above the bitter cold of space, and that's out in the asteroid belt. The night-side temperature is 250 degrees colder. Chilly for your crew but still pretty darned hot compared to space. That gives you nice, big window where you can radiate your waste heat. You simply radiate the heat cleverly as if you were a rotating body whose sunward side has now pointed starward and is radiating its stored heat. To the IR sensors throughout the system, you just look just like every other boring rock out there.

 

And just to forestall the potential argument, the fact that your ship may be on a highly eccentric or even hyperbolic orbit is not in the least suspicious. It happens all the time. That's why it's so important to have a continuous LIVE database of EVERY object in the solar system and its current trajectory along with its IFF.

 

So, basically, stealth in space isn't about hiding your ship from detection, but hiding it from identification.

 

Stealth attacks on important or strategic systems with a massive detection grid in place won't work, but in less important systems, it might be possible, and it certainly allows for pirate attacks on unsuspecting vessels traveling through poorly charted solar systems. Imagine your surprise when that 18th magnitude object your ship's scanners identified as the heat signature of a small asteroid with a 14-hour rotation period just opened fire on you.

[Zeropoint]

Re: Space Warfare II - Stealth Reconsidered

 

Two points: First, your ship would be picking up just as much energy from the sun as anything else at its distance from the sun. Second, your ship has a power source on board, and the asteroids don't.

 

It's not possible for your ship to be at equilibrium temperature, unless you're storing your heat output in an internal heat sink, and as Nyrath demonstrates, those won't last long enough to be useful unless they're HUUUUUGE.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Yes, my ship is picking up the same energy on the sunward side as everything else. On the darkside, it isn't picking up anything. It's radiating.

 

Second point: of course my vessel isn't in equilibrium. It's heating up on the day side and cooling off on the dark side. No rotating body in sunlight is in thermal equilibrium in the strictest sense, so that was a poor word choice on my part. What I meant by thermal equilibrium is a repeating cycle of heating and cooling. The engineering challenge is making my ship radiate in a way that mimics a naturally cooling rotating body. And I'm rigged for silent running which means I'm running on 100 KW worth of fuel cells and am not pumping out gigawatts of waste heat.

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

So' date=' basically, stealth in space isn't about hiding your ship from detection, but hiding it from identification.[/quote']

Well, yes and no. It's not that hard to determine distances (you need parallax detection, probably requiring two ships at a separation of some kilometers, but that's not that hard to accomplish), at which point it's no longer good enough to get yourself lost in the volume of all the objects floating around out there, you have to get lost in the volume of objects out there that are in the area of interest. If you only care about objects within, say, a tenth of an AU of you, unless you're in a region of particularly cluttered space, something the size of a ship will stand out. Overall, it's pretty practical to hide as long as you don't go anywhere near anything of interest and you don't do anything, but, well, this fact doesn't have a lot of military application.

Imagine your surprise when that 18th magnitude object your ship's scanners identified as the heat signature of a small asteroid with a 14-hour rotation period just opened fire on you.

First of all, 18th magnitude is actually pretty bright and would likely be tracked. Second, well, an 18th magnitude object, unless incredibly small, is still probably upwards of a million kilometers away, making it rather unlikely to be able to 'open fire'.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

First, dealing with the space is only mostly empty issue. Your detection system is going to have to have a complete, continually updated database with EVERY object in your solar system, and I mean every object. That means stuff in the oort cloud, too, so if a comet gets nudged, you can spot it instantly and send someone out to find out if it's a natural object or something more sinister. Remember those cometary fragments are hotter than background space, too, and their IR could be a ship rigged for silent running.

 

This is a major investment in time and resources, which means only highly strategic or important systems are going to have that kind of detection infrastructure. Border systems and less important worlds aren't going to have it. That allows us stealth using the other false assumption: that your ship is the only hot object in the universe.

Not quite.

 

Sitting on my desk right now is a one terabyte hard drive, which I use for my iTunes music and movie files. Not gigabye. Terabyte. It cost about a hundred bucks. By the time we have space warships, a hard drive with enough memory to contain such an astronomical object database will be the size of your thumb and cost the equivalent of about fifty cents, and be available at the check-out counters of your local office-supply store.

 

And all astro-militaries will maintain such databases. Why? Do you know how much damage a re-directed asteroid can do to Earth? Think "dinosaur killer." The astro-militaries of all nations will keep close tabs of the orbits of all small bodies, just to be sure there are no unauthorized changes in their orbits.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Well' date=' yes and no. It's not that hard to determine distances (you need parallax detection, probably requiring two ships at a separation of some kilometers, but that's not that hard to accomplish), [/quote']

 

Once again, the need for a detection infrastructure present in space. I stated in the original post that stealth is ineffective against systems with such a structure in place, so you have no argument from me here.

 

at which point it's no longer good enough to get yourself lost in the volume of all the objects floating around out there, you have to get lost in the volume of objects out there that are in the area of interest.

 

It's not a question of getting "lost" in anything. I'm not hiding. I'm pretending to be something I'm actually not. Just another rock. Space is full of them.

 

If you only care about objects within, say, a tenth of an AU of you, unless you're in a region of particularly cluttered space, something the size of a ship will stand out. Overall, it's pretty practical to hide as long as you don't go anywhere near anything of interest and you don't do anything, but, well, this fact doesn't have a lot of military application.

 

Except for recon and ambushes in border systems with poor detection infrastructures.

 

First of all, 18th magnitude is actually pretty bright and would likely be tracked. Second, well, an 18th magnitude object, unless incredibly small, is still probably upwards of a million kilometers away, making it rather unlikely to be able to 'open fire'.

 

It was just an example pulled out of thin air to illustrate the point because I didn't want to figure out the absolute magnitude of a 50-meter long cylinder with an albedo of .03 at 3.5 AU. Besides, a million kilometers away is a nothing shot for a good laser. Laser range is primarily limited by lightspeed lag. And lightspeed lag is only an issue if you're doing evasive movement, and why would you be wasting propellant on evasive maneuvers if you don't know I'm there?

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Not quite.

 

Sitting on my desk right now is a one terabyte hard drive, which I use for my iTunes music and movie files. Not gigabye. Terabyte. It cost about a hundred bucks. By the time we have space warships, a hard drive with enough memory to contain such an astronomical object database will be the size of your thumb and cost the equivalent of about fifty cents, and be available at the check-out counters of your local office-supply store.

 

Probably not. Physics limits the density of things like these. But regardless. Storing the data isn't the issue. Gathering the data and monitoring for changes is. That requires sensor platforms and monitoring stations and ships and logistics to back it up. It's a non-trivial investment of resources, even for a spacefaring society. I addressed this in my original post. This will not work in systems with good detection networks. Not all systems will have good detection networks because of the required investment of resources. We don't fly U-2 spy planes over every square inch of the planet and we don't re-task spy satellites just because. We only do it for areas of high strategic interest.

 

Identically, interstellar governments of the future won't be putting military-quality detection grids throughout every star system; only those with sufficient commercial or strategic value.

 

And all astro-militaries will maintain such databases. Why? Do you know how much damage a re-directed asteroid can do to Earth?

 

No they won't because they won't need to. Do you know how much energy it takes to nudge an asteroid? They don't need to track the rock, they'll spot the heat plume of the reaction drive needed to move it. Just like you can't move your ship without giving it away, no one can move an asteroid without giving themselves away. You don't need to spend a billion credits identifying and tracking every possible piece of dangerous rock. All you have to do is look for big mass moving heat blooms.

 

So, again, in poorly charted solar systems, stealth is completely possible by simply mimicking the radiative cooling of a naturally rotating object in sunlight. It won't work for major military assaults, but it will for recon and ambushes.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Probably not. Physics limits the density of things like these. But regardless. Storing the data isn't the issue. Gathering the data and monitoring for changes is. That requires sensor platforms and monitoring stations and ships and logistics to back it up. It's a non-trivial investment of resources' date=' even for a spacefaring society[/quote']

No, you can do most of the job with ground based telescopes, and a couple of orbital ones for the rest.

 

 

 

No they won't because they won't need to. Do you know how much energy it takes to nudge an asteroid? They don't need to track the rock' date=' they'll spot the heat plume of the reaction drive needed to move it. Just like you can't move your ship without giving it away, no one can move an asteroid without giving themselves away.[/quote']

The energy goes down by orders of magnitude with the distance between the asteroid and the primary star. For something in the Kuiper belt, it is quite modest.

 

And if you can spot the reaction gently nudging a rock that far out, you can certainly spot a hostile spacecraft attempting to insert itself into an asteroid imitating orbit.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

No' date=' you can do most of the job with ground based telescopes, and a couple of orbital ones for the rest.[/quote']

 

The fact that we haven't as of today is pretty compelling evidence that it's not going to be as trivial as you seem to maintain it will be. I think I'm safe in maintaining that the caliber of detection you're arguing for is going to require a non-trivial investment both on worlds and in space.

 

 

 

The energy goes down by orders of magnitude with the distance between the asteroid and the primary star. For something in the Kuiper belt, it is quite modest.

 

Well, yeah, if you don't mind it taking a couple of decades for your killer weapon to hit. You can do anything in space cheaply if you're willing to let it take a really long time.

 

And if you can spot the reaction gently nudging a rock that far out, you can certainly spot a hostile spacecraft attempting to insert itself into an asteroid imitating orbit.

 

I wasn't aware there was a mandatory orbit required to be considered an asteroid.

 

For a recon mission, I come in on a hyperbolic orbit. All kinds of stuff in our solar system are on hyperbolic orbits. It's not suspicious in the least.

 

If I'm a pirate, I pick my spot in advance and set up my ambush and wait for unsuspecting ships to come by.

 

Like all stealth, you don't have undetectable carte blanche. But that's fine, because that's what drives plots. The point I'm making is that it is theoretically possible. Once you get the theory down, then you're into engineering details and tactics. And science fiction allows you to claim "they somehow figured it out," when it comes to engineering details, and your story plot gets to explore the tactics.

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

Besides' date=' a million kilometers away is a nothing shot for a good laser. Laser range is primarily limited by lightspeed lag.[/quote']

Urr...not for hard science lasers. Laser range is mostly limited by the resolution of your optics, which is in turn limited by diffraction. If you have, say, a 10 nanometer hard UV laser, which is about the upper limit for physical mirrors, and your focal array is 10m across and diffraction-limited, beam divergence is 1e-9 radians, or one meter at a million kilometers, which is almost certainly substantially below the threshold of doing anything useful to the target at all. At the same time, any tech capable of building that laser is also capable of building sensors that vastly outperform anything currently available. If you limit yourself to what could plausibly be built without vast improvements in optics technology (resulting in improved detection technology), effective range is probably going to be a thousand kilometers or less.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

The fact that we haven't as of today is pretty compelling evidence that it's not going to be as trivial as you seem to maintain it will be.

There is "civilian-trivial" and then there is "military-trivial."

Even though there is a real threat today from errant asteroids, all current governments are loath to spend the modest amounts required for an asteroid survey and sky watch.

This would instantly change if there was a demonstrable threat from attacking alien warships or Footfall-like asteroid strikes.

 

Be that as is may, new asteroids being discovered by astronomers are dimmer than prior discoveries. The lower the dimness of undiscovered bodies, the harder for a space pirate to hide.

 

I think I'm safe in maintaining that the caliber of detection you're arguing for is going to require a non-trivial investment both on worlds and in space.

I don't think so. Current technology can do a full sky scan of all objects down to magnitude 12 or so in four hours flat. Future technology will improve on that.

 

 

I wasn't aware there was a mandatory orbit required to be considered an asteroid.

Heh, no. Presumably your pirate ship cannot teleport from its home base to the point where you say it will hide in plain sight. I could find no concise way of expressing that, but that's what I meant by "asteroid orbit."

 

Which means you'll have to use your main engines at your base to inject yourself into a trans-plain-sight-hiding-spot trajectory, and use the engines again to slow down into a pseudo-asteroid orbit. Both of which will be quite noticeable by any observer based in the same solar system.

 

 

If I'm a pirate' date=' I pick my spot in advance and set up my ambush and wait for unsuspecting ships to come by.[/quote']

Oh, come now. You know orbital mechanics better than that.

Nothing is stationary in space unless it is under thrust. To wait at a spot for a ship to come by, you'd have to counteract the Sun's gravitational acceleration by burning your engines. This is a dead giveaway that you are not an asteroid. You can be a statite by unfurling a large mirrored solar sail but the same objection applies.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Laser range is primarily limited by lightspeed lag.

I was going to point out the diffraction limit but ajackson beat me to it.

You can find the equation here:

http://www.projectrho.com/rocket/rocket3x.html#laser

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

There is "civilian-trivial" and then there is "military-trivial."

Even though there is a real threat today from errant asteroids, all current governments are loath to spend the modest amounts required for an asteroid survey and sky watch.

 

It's not modest, or they wouldn't be loathe to do it. You're contradicting yourself.

 

 

This would instantly change if there was a demonstrable threat from attacking alien warships or Footfall-like asteroid strikes.

 

Yes, if the world were strategically important enough to warrant it. Which point I made in my initial post. On strategically important worlds and systems, stealth is a no-go.

 

 

I don't think so. Current technology can do a full sky scan of all objects down to magnitude 12 or so in four hours flat. Future technology will improve on that.

 

Then why haven't we? Once again, your argument shows a disconnect from reality. I'm beginning to catch the whiff of agenda here.

 

Heh, no. Presumably your pirate ship cannot teleport from its home base to the point where you say it will hide in plain sight. I could find no concise way of expressing that, but that's what I meant by "asteroid orbit."

 

That's a question of tactics. And it's also why certain routes will be known as "pirate space" because they are areas where it's easy to set up the ambush. Ships will only go there when the potential reward outweighs the risk.

 

Which means you'll have to use your main engines at your base to inject yourself into a trans-plain-sight-hiding-spot trajectory, and use the engines again to slow down into a pseudo-asteroid orbit. Both of which will be quite noticeable by any observer based in the same solar system.

 

Yep. That's why it won't work for every system. If you have interstellar trade going on, this again devolves to tactics.

 

Oh, come now. You know orbital mechanics better than that.

Nothing is stationary in space unless it is under thrust. To wait at a spot for a ship to come by, you'd have to counteract the Sun's gravitational acceleration by burning your engines. This is a dead giveaway that you are not an asteroid. You can be a statite by unfurling a large mirrored solar sail but the same objection applies.

 

Yep. Again, this is tactics. You will basically have ambush windows of opportunity.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

I was going to point out the diffraction limit but ajackson beat me to it.

You can find the equation here:

http://www.projectrho.com/rocket/rocket3x.html#laser

 

Yep. But you forgot about this part:

 

http://www.projectrho.com/rocket/rocket3x.html#xray

 

You can make the configuration disposable and bomb-pumped to make the engineering problems much less challenging.

 

I personally liked your phrase "still a ravening death beam at one light minute."

 

Which, by the way, also gives me cover (due to lightspeed lag) to launch my weapon, get it to safe range and fire it off before my target sees what I'm doing.

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

It's not modest' date=' or they wouldn't be loathe to do it. You're contradicting yourself.[/quote']

I guess you didn't read the part about "civilian-trivial" and "military-trivial."

 

Yes' date=' if the world were strategically important enough to warrant it. Which point I made in my initial post. On strategically important worlds and systems, stealth is a no-go.[/quote']

So you are saying that one can only have stealth where the target solar system is a Firefly-esque type populated with people riding horses? Can't argue with that.

 

 

Current technology can do a full sky scan of all objects down to magnitude 12 or so in four hours flat. Future technology will improve on that.

 

Then why haven't we?

Ummm, maybe because we have? Have you spoken with any astronomers lately? I know I few I can link you up with.

 

Once again' date=' your argument shows a disconnect from reality. I'm beginning to catch the whiff of agenda here.[/quote']

Heh. Perceived atramentous tetsubin syndrome. In an ad hominem argument.

 

 

And it's also why certain routes will be known as "pirate space" because they are areas where it's easy to set up the ambush. Ships will only go there when the potential reward outweighs the risk.

Ummmm, have you had any orbital mechanics at all? I thought you did. There are no "routes" in space. Not ones that you can travel over a second time without a delay. Since both your starting point and destination are moving at different speeds, they generally will not repeat that configuration until a couple of years have passed. The technical term is "synodic period."

 

The only place that pirates can reliably ambush a merchant vessel is on the ground at the launching spaceport or the landing spaceport.

 

 

 

Nothing is stationary in space unless it is under thrust. To wait at a spot for a ship to come by' date=' you'd have to counteract the Sun's gravitational acceleration by burning your engines. This is a dead giveaway that you are not an asteroid. You can be a statite by unfurling a large mirrored solar sail but the same objection applies.[/quote']

Yep. Again, this is tactics. You will basically have ambush windows of opportunity.

ummmm, what window?

If the pirate is hovering in space with its engines burning for a few weeks waiting for the merchant ship to get close enough to attack, don't you think the merchant ship will notice and ask the Space Patrol for help?

[Nyrath]

Re: Space Warfare II - Stealth Reconsidered

 

Yep. But you forgot about this part:

 

http://www.projectrho.com/rocket/rocket3x.html#xray

 

You can make the configuration disposable and bomb-pumped to make the engineering problems much less challenging.

 

I personally liked your phrase "still a ravening death beam at one light minute."

 

Which, by the way, also gives me cover (due to lightspeed lag) to launch my weapon, get it to safe range and fire it off before my target sees what I'm doing.

Heh, read it again.

"ravening death beam at one light minute" is in the section of Non-bomb x-ray lasers. This is the kind where you need an accelerator ring about one kilometer in diameter. Unless your ship is the Death Star, it isn't going to be carrying one of those.

 

If you do the math for the bomb-pumped x-ray laser, you'll find that the effective range is much shorter.

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

If you do the math for the bomb-pumped x-ray laser' date=' you'll find that the effective range is much shorter.[/quote']

Due to a lack of effective X-ray mirrors, beam spread is the sum of the aspect ratio of the lasing crystal and the diffraction limit. If we assume soft X-rays at 1 nanometer and lasing crystals 10 meters long, aspect ratio is 1e-1*width, diffraction is 1e-9/width, and we get the best value at width = 1e-4 (0.1mm) where both limits are 1e-5 so our beam divergence is 2e-5 radians, or 20cm per kilometer.

[Kraven Kor]

Re: Space Warfare II - Stealth Reconsidered

 

LOL - even though I haven't rep'd anyone for months or years...

 

"You must spread some reputation around before giving it to Nyrath again."

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

I guess you didn't read the part about "civilian-trivial" and "military-trivial."

 

I did. It's a distinction without a difference. You're discussing levels of degrees, not the fundamental issue.

 

So you are saying that one can only have stealth where the target solar system is a Firefly-esque type populated with people riding horses? Can't argue with that.

 

Or one with early 21st century technology like Earth where it's not considered worth the effort. Or one where for political reasons one may not be deliberately put in place.

 

Ivory towers have little or no resemblance to the real world. There are many reasons why a solar system may not have a 100% stealth-proof detection system in place, but still have significant space travel.

 

Ummm, maybe because we have? Have you spoken with any astronomers lately? I know I few I can link you up with.

 

Um, yeah, we've done complete sky scans, but not in 4 hours. The Astrographic Catalog was divided among 20 observatories in order to reduce the burden of the task and took years to complete. The current US Naval Observatory catalog is the result of 50 years' work, yet it is only assumed to cover the entire sky, and only has an 85% accuracy in identifying stellar from non-stellar objects. The spaceguard report says that it will take six 2.5 meter telescopes 10 YEARS to plot 90% of near-earth large asteroids. 10 years, and it doesn't even get all of them. Real-world examples always trump theoretical postulations. This detection system you toss about so casually is not going to be as trivial, even militarily, as you maintain it is.

 

Ummmm, have you had any orbital mechanics at all? I thought you did. There are no "routes" in space. Not ones that you can travel over a second time without a delay. Since both your starting point and destination are moving at different speeds, they generally will not repeat that configuration until a couple of years have passed. The technical term is "synodic period."

 

Synodic periods are routes. By definition. You said so in your last sentence, in direct contradiction to your first sentence. Ships with limited deltaV are constrained to porkchop plot routes. Torchships run shortest-time routes. Routes exist in space.

 

ummmm, what window?

If the pirate is hovering in space with its engines burning for a few weeks waiting for the merchant ship to get close enough to attack, don't you think the merchant ship will notice and ask the Space Patrol for help?

 

The window where the pirate's orbit comes within range of the route ships moving between worlds must follow. No engine hovering required. A typical tactic would probably be something along the lines of setting up a hyperbolic orbit when nobody's around and then hoping someone shows up at the right time. If no one does, reset and try again.

 

There are many possible scenarios where setups like this can exist. A slight adaptation of the current Somali pirate practices is just one example.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Heh' date=' read it again.[/quote']

 

I read it better than you, because I spotted that even though you corrected yourself on there being no such thing as x-ray mirrors, your bomb-pumped example happily goes on talking about how inefficient the laser is because there are no x-ray mirrors. In other words, your math is wrong. It's very possible for me to make a ravening beam of death from a one-shot bomb-pumped laser.

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

A follow-up on the 4-hour sky scan and why it won't work.

 

The number comes from the Atomic rocket web site and is calculated by assuming a single wide-angle lens is taking 30 second exposures of 100 square degrees at one time to pick up 12th magnitude signals.

 

 

 

Except you won't get 12th magnitude signals. You'll get a whole bunch of overexposed lower magnitude images, washing out everything else on your plate.

 

The longer your exposure, the narrower your field of view has to be. It's physically impossible to look for 12th magnitude stars in 100 square degree chunks of sky at a time. Looking for twelfth magnitude stars restricts your field of view to arc-minutes or even arc-seconds. Suddenly, your 4-hour sky scan has turned into a 4 year sky scan.

 

And it gets even better. You have to take repeated pictures of the same portion of the sky, gradually narrowing down your field of view on the dark regions as you increase your exposure times. And if your 12th magnitude star is too close to a 4th magnitude star, you'll never spot it.

 

Which is another reason why you need sensor platforms scattered about your solar system. You need to take photos of the same portion of the sky from different angles to prevent a ship from hiding its 12th magnitude drive exhaust in the light of a 4th magnitude star. Yes, I know you can do a spectral analysis on the 4th magnitude star and find out that it has some unusual doppler characteristics. But that means you're going to be doing more than just taking pictures. Increase your sky scan yet again.

 

Moral: Stealth-proof detection systems are not trivial.

 

Because, to quote 2001 (the novel) "My God, it's full of stars!"

[ajackson]

Re: Space Warfare II - Stealth Reconsidered

 

The longer your exposure' date=' the narrower your field of view has to be.[/quote']

Nope. The longer your exposure, the smaller your pixel size has to be. Now, I don't know of any system equivalent to said 12th magnitude scan, but I do know of the Large Synoptic Survey Telescope, which surveys 10 square degrees at a chunk (about 4,200 frames to cover the sky, if it had sufficient coverage) down to magnitude 24.5. Build a few of those and you're scanning most of the sky (you'll have a bit of a dead spot near the sun) nightly.

It's physically impossible to look for 12th magnitude stars in 100 square degree chunks of sky at a time. Looking for twelfth magnitude stars restricts your field of view to arc-minutes or even arc-seconds.

See the above.

[CorpCommander]

Re: Space Warfare II - Stealth Reconsidered

 

I was under the impression Governments were much more active in things like Sky Guard after the Shoemaker-Levy 9 comet strike on Jupiter. Perhaps that interest was short lived.

 

How long does it take to do a whole sky survey? My question here is aimed at determining how "instant" detection would be for various energy outputs. The earlier post about there being a lot of junk in space was something I had been thinking about. How do we know some of the asteroids AREN'T alien space stations watching over us? How often are we looking? Apparently not very often at all. At what point does a world suddenly decide to start looking and watching? Maybe not until after it's first pearl harbor in space! At which point it is too late, their planet is enslaved. So maybe you only need to be stealthy once per system, early enough.

 

How much energy would it take to move an asteroid into Earth orbit? Once it makes it's run how much energy would it take to prevent a collision (would that even be possible?)

[CorpCommander]

Re: Space Warfare II - Stealth Reconsidered

 

What other civilizations are detecting about us: http://abstrusegoose.com/strips/electromagnetic_leak.PNG

[frgough]

Re: Space Warfare II - Stealth Reconsidered

 

Nope. The longer your exposure' date=' the smaller your pixel size has to be.[/quote']

 

Nope. CCDs suffer from blooming when the pixel well is overloaded (the equivalent of photographic overexposure). It doesn't matter how many pixels you have. You get too much light coming in (long exposure time) and you'll get blooming all over your image.

 

If you want to pick up faint objects, you have to mask out the brighter ones. That means tighter fields of view.

 

Now, I don't know of any system equivalent to said 12th magnitude scan, but I do know of the Large Synoptic Survey Telescope, which surveys 10 square degrees at a chunk (about 4,200 frames to cover the sky, if it had sufficient coverage) down to magnitude 24.5.

 

It can do 10 square degree shots or go down to 25th magnitude. Not both. See the above about blooming.