JackOfShadows wrote:

The biggest problem with stealth in space is that you're entirely backlit. We tend to think of space as this big black expanse but with the right optics it's a giant sea of light. And as such it's pretty easy for an AI to track objects moving against that sea unless you're using some sophisticated thermoptic camo.

Not even unless - even the best thermal camouflage has to put that heat somewhere, which means it's going to show up against the cold blackness of infinity. You can't just not radiate heat...I mean, barring certain bizzare exotech. Seconding the asteroid bit. That or pretend to be space debris, like in Firefly.

Would it be possible to have thermal ballast? Like a material design to soak heat and then be jettisoned, possibly with a bit of reactor mass to alter its trajectory? (poli sci major here, forgive my scientific ignorance)

Right, but does that cool your 'stealth' ship so you can coast into proximity to your target without the huge heat signature because you dropped it a couple AU behind you?

uwtartarus wrote:

Right, but does that cool your 'stealth' ship so you can coast into proximity to your target without the huge heat signature because you dropped it a couple AU behind you?

It doesn't cool your ship, it just concentrates some of the heat in one place. That in turn makes your ship easier to see. Radiators will cool your ship, but they do that by dumping as much heat as they can in all directions. You can dump the heat sink overboard but the parts of your ship that were holding it and the heat pipes that were running into it will still be just as hot.

I will point out that you don't have to radiate heat [i]everywhere[/i]. With a directional radiator, you can radiate heat towards nobody's sensors. It may not be the most efficient way of dumping heat, but you don't need efficient, you need unseen. As for detecting the engine burn, there's ways around that. Use some kind of cold-gas propellant to put you on your intercept course. It's hideously inefficient, but again, the point is unseen. You can also use alternate forms of acceleration - plasma sail, mass driver, etc. And of course, if you're so small that the target doesn't really notice you - say, the size of a human - then you're aces. Stealth in space is [i]hard[/i]. It is not impossible.

And of course, if you want to be a [i]real[/i] shitler, you can always use that most hated fallback, the false SOS. Interception becomes literally trivial if your target comes to you. Of course, if that shit goes on too much, folks will start answering SOS calls with missiles.

It's only the default response for people who've seen the horrors that Firewall tries to cover up. If you're a regular joe, you'd never suspect that a derelict freighter with no heat signatures and an active SOS contains a dozen exurgents in hibernation.

http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold Space can be cold or hot. Comets aren't evaporating because its cold.

uwtartarus wrote:

http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold Space can be cold or hot. Comets aren't evaporating because its cold.

Yeah they aren't evaporating because space is hot either. This week on "I Didn't Read The Page I Linked"... Since we're linking TVTropes as a scientific authority now, you'll like http://tvtropes.org/pmwiki/pmwiki.php/Main/StealthInSpace

So, since true stealth is impossible what you're aiming for is to reduce your signature until it's too small to be a concern. I could see a kind of camouflage in the form of an inflatable double-walled balloon with dark radar absorbing material on the outside. Instead if a heat sink, perhaps a bottle of liquid nitrogen is leaked into the balloon. As the gas expands it cools the envelope, further obscuring the morph inside. Trajectory would be important as you don't want debris avoidance/elimination systems to tag you as a threat- getting railgunned before getting to the target would be detrimental to the mission! With a slow approach speed, jumping out and latching on with a tether to slow down may work. Anything larger than a morph would have to pretend to belong there or have the groups hacker compromise the targets systems. How big are harvester drones? I have occasionally wondered if a shut down swarmanoid on a timer could drift over to Zombieland and switch on when enough bots settled on the surface.

I mean, if we're being super technical, there are particles of stuff in the region called "space" which has a variable temperature based on where it is in space relative to other discreet objects. And in a very scientific sense, "space" has a very low ambient temperature. The real thing is that as a "thing", space is like 99% vacuum, and as noted, radiation is a very poor method of heat removal especially at the human's relatively low level of temperature. You go out into the void between stars and space is effectively very cold because background radiation is like 3 K. But it'll take a pretty long amount of time for the heat from you to bleed out completely (meanwhile, staying on topic, anybody with a sufficiently sized IR telescope pointed in your direction is going to see you lit up like a spacemas tree). On the second point, space is really big, way bigger than most people remember to give it credit for, so for humans (or transhumans) we live relatively close to a big, non-space source of heat. To again bring this around to stealth in space, that also means that unless you're pretty far away from the sun (which, funny story, actually makes it easier for other people to see you because it's much easier to pinpoint a heat source) or use special materials (which absorb the radiation and thus mean you generate more heat) there is a giant cosmic back-light on most objects in the solar system. This does, however, bring us to a new subject of possible stealthy approaches, coming at them from out of the sun, dogfighter style.

Okay, using my Mighty Brain, I have determined that the defining element for stealth is how big the ship's radiators are relative to it's size, which is determined by how much power they require and how good EP heatpumps are. For simple aesthetics, I favour the idea that modern EP tech is good enough to keep the heat a ship generates confined to a heatsink connected to a near-blackbody radiator. Assuming this is so, one must first direct all output heat to the radiators, so the hull remains cool. This can be done relatively simply in EP, through the use of a secondary hull "shell", separated from the primary hull by a vacuum gap, with additional cooling provided through liquid helium.* As all heat is being lost through the radiators, the only requirement then is to render the emitted heat directional, and this is essentially trivial; mount the radiator in a parabolic reflector and cover it with a collimating lens**, and the heat will be radiated in a laser-like beam. Directed away from the thing being hidden from, or simply perpendicular to the solar plane, and the heat is for all intents and purposes undetectable. * I like the idea of hexagonal plates of diamond, coated with an ablative, high emissivity foam or aerogel, with "table-legs" which lock into cavities in the primary hull surrounded by helium reservoirs. This would ease maintenance and construction, and would provide an extremely effective defense against energy weapons, as the high thermal conductivity would prevent local heating, and should that prove insufficient the boiling helium would both eject the compromised hull plate as well as form a “cloud” to diffuse lasers. ** Whilst lenses of sufficient quality do not exist IRL (I think), they exist explicitly in EP thanks to metamaterials – laser weapons could not exist without them.

geckopirateship wrote:

Just a reminder, I'm talking about a scenario where the "stealth craft" is either launched towards its target or burns off some fuel to get itself started and slowly drifts towards its target, so it isn't actually burning fuel during the trip, it's just slowly floating ahead...

We know. The issue isn't the burning of fuel, but the fact that the “stealth craft” will emit heat at detectable levels even when just drifting – the discussion is whether it's possible or practical to conceal those emissions.

The issue is always that, any ship or habitat will be scanning for anything larger than a grain of sand because of the collision threat, and most of those objects are already pretty cold. So you need to be colder, smaller on radar, and block fewer light sources than that. If you don't meet those requirements, you need to at least look nondescript and on a non-collision course, then when you're close enough, kick on the engines and close the gap.

You have to think about something, every single ship that its in space its suceptible to be detected and such information can be sent to everyone freely so even if your heat is carefully being sent in a complete opposite direction the space is too big for someone to don't notice it and will be registered, maybe not by your enemies but those enemies can recieve that information and since your mission depends on one burn and wait to get close, distance lag can't be applied. So we still have the same thing, space stealth is impossible, I don't even thing that machines can't work on a 100% efficiency so they will even build heat inside and need radiators(and also think about the sun that is sending radiation and heat at the same time). You have to be a narrator, create a world with rules that can actually give you something similar to space stealth or infiltration. For example; You can create certain space ships that have a particular disadvantage, from time to time they have to leave behind small fuel containers, that casually can hold a small infiltration team, and now we put something so those fuel container can approach space stations, lets say that they can be easily sold for a moderate ammount of money so you negotiate with potential clients nearby about who to send it(for the irony of course) before launching it, and casually give it to a certain costumer. So you sent it and it will get pretty hot for a long time, but thats perfect to still hide your infiltration team. Clients will take caution, like wait for the fuel tank to completly cool off or fill it with radiation or acid and things like that BUT with this you actually made it, because wether they suspect or not there is an infiltration team inside the tanks such team is already close enought to avoid more general scanners like thermal or lidar. Of course this has problems, what if we're talking about a misterious secret station that is not supossed to answer your call or they simply reject them for security reasons? What if we're not talking about humans but a station full of exsurgents that you prefer they don't know you're coming? But still this adds narration, imagine struggling to sell that fuel tank to a paranoid client, or trying to convince everyone that your reputation in guanxi is just from friends who know friends, or while the fuel tank is at his way to the station someone comes and steal it thinking its an easy catch for money... and so on. I don't really think EP is about how big is our technollogical knowledge, thats a bonus or a nice detail, but narration and the world we construct around EP with our imagination its the basis that we should take, so if we have already discussed(give me cent for every time someone has started a topic like this AFTER reading about how imposible is stealth in space and I would be rich) that if there is a way to be stealthy in space is out of our comprehension and the only way to do it is with the handwavium of "metamaterials, metamaterials magic" I think it would be much more fun to create a set of rules that respects the general idea of stealth in space, with their advantes and disvantages than just constantly oppose the idea.

Jim_Callahan wrote:

templariomaster wrote:

You have to think about something, every single ship that its in space its suceptible to be detected and such information can be sent to everyone freely so even if your heat is carefully being sent in a complete opposite direction the space is too big for someone to don't notice it and will be registered,

Actually, the default setting for Eclipse Phase is that humanity is only barely nudging at the mid to high end of Kardashev Type 1. Nothing's stopping you as a GM from upgrading use to Type 2 and saying we're capturing every bit of radiation from the solar system (that would certainly make the setting a lighter, softer, generally happier place), but by default if you posit a mechanism by which you could turn your heat emissions into a beam, space being big works in the _opposite_ direction... point that beam in a random direction and in the vast majority of space your chances of the beam hitting anything at all, much less a detection unit, is on the order of one in a trillion or quintillion-ish. The idea of detection networks being able to track anything that turns off its transponder at ALL after you do something to initially lose tracking is actually kind of a fudge based on Science Fiction having no sense of scale, it only really works because we're positing infinitely fast, arbitrarily massive computing power behind every little thing. In the real world space is so bleeding huge and empty that NASA regularly loses track of objects where they in theory already know the trajectory and where to look. And that's BEFORE we get into your defender's comms with your sensor array being light-speed limited and all the shenanigans you can pull with the minutes to hours of lag there. If we were talking real-world physics and not RPG physics it'd be a matter of releasing a decoy with your radar profile and heat signature, opening up some coolant valves as you turn off your beacon and shift vector, bam, done, you're off the grid. It only has to go beyond that because the defensive computing arrays functionally break every law of materials science, computing, and EM physics.

If we put things into kardashev 2 we don't really now what consequences could be, we have problems thinking about the consequences of having virtual spaces undistinguisble from reality or what counscioness is when we could copy and modify it, lets not think about ships that can efficiently convert all his heat at 100%, because for example; all lasers could be death rays with that 100% efficency. The problem with stealth in space is that anything lightly above the background is suceptible of being detected, and detecting heat in space isn't something exclusive to NASA today let alone all eclipse phase with all the factions constantly putting sensors to track everything the other does. And now think that all the ships that emit heat can be detected at ranges as long as the end of the start of the solar system, that makes perfectly possible to track every single ship emitting heat out there. And If you throw out a decoy, you would have to emit the same amount of energy in the same way with the same mass and with the same form... I think that almost for a few credits more you can fill the rest and have a spaceship. And still your ship needs to emit heat, if we go out of the 100% kardashev super efficient heat lasers, the other way is with radiators that can't be silenced, even if you think about liquid refrigeration it can't last long, at least not space time travel long.

For what it's worth, I think the "masquerade as debris" idea would hold a lot more weight in some orbits than others, especially in orbits where there was heavy fighting in the Fall, or other conflicts between habs, ships, etc. Anything near Sol-Earth and Sol-Mars is going to have a few million tons of scrap floating around, and it's more economical to build your habs to withstand the smaller pieces than it is to shoot them, and then have a ton of microdebris that's still moving damn quick and is much harder to account for/map. Mapping debris is probably a thankless but essential job in most orbits. This could give any insertion team a chance to piggyback known or plausible wrecks (or make their own). You'd still have to deal with your IR signature (which again is going to depend on your orbit due to needing to shield yourself against inner system solar radiation, etc.) but that's just an engineering problem, and if you're doing what's basically an orbital drop, odds are you're brute forcing it anyway if you need to get those morphs on site now, as opposed to smuggling them or being tricky about egocasting, building on-site, etc. That does raise another problem. The nigh-frictionless nature of space means that once an object heads off on a trajectory, it's gonna keep going in that orbit unless acted upon. The big battles are going to be known about and there are no doubt "weather station" groups and AGIs whose main job is to keep an eye on battles, collisions, etc. and extrapolate where the big pieces are going. Which means that any decent rockwatcher on that hab is going to notice if all of a sudden a new piece of debris is angling toward them without any notifications of a new battle or something. If a wrecked ship happens to get caught in a gravity well and its orbit warped enough to be close (i.e. within a few dozen or hundred kilometers -- space is big, again) you would have a natural cover, but they'd also be watching that very closely. Unmapped debris the size of a human is going to peg a lot of warning lights, especially if no other habs in that orbit or near orbits have any idea what you're talking about when you query them. Which means your anti-radar gear better be up to snuff. There's also the not-insignificant hurdle of going fast enough to have a rapid approach while still being able to slow yourself down enough to not turn into abstract art on the station's hull, which is going to require reaction mass of some sort. I have no idea of cold-gas systems can slow you from an approach speed to something you can touch down with softly enough to stay in control and not alert any physical security systems. Aim for the exterior clanking masses getto, I'd say. Though thinking about that some more, if you're not going relatively fast enough to splatter yourself, you're not going fast enough to dent the hull. So it may not matter at all if you're spotted via radar as long as you don't look like an insertion team. From the point of view of the station security, if they know it's not threatening and not going fast enough to do any damage, it's probably going to either bounce off or settle against the hull, which means it's not an immediate problem. Not that they'd ignore it, but it probably wouldn't be a priority, especially if you piggyback a larger debris cloud. Personally, I think stealth in space is as much a matter of taking advantage of the human element, setting up moles and plants beforehand to pass bribes or sabotage equipment at the opportune moment. But that's just me.

That's also going to go up like a flare to any stations in that orbit, so they'll be watching it as soon as the EM emissions hit their sensors. In the latter, pirate scenario...what do you wager is more cost effective, as an aside? The repairs from a big chunk of rock hitting your hab or the reaction mass to move out of the way? Though yeah...on a lighter note, if my many, many failed docking attempts in Kerbal Space Program are any indication, it's hard enough to get two things to touch each other intentionally in space. And doing that in a non-planetary orbit would only exacerbate the scenario. Really, unless I'm missing something, physically stealthing into a station at this point seems like it would take tremendous planning, perfect timing, a long, long time, and no small amount of luck. Not exactly HELO dropping behind enemy lines, it isn't.

actually i just remembered something about active radar control software. today's radar installations are powerful enough to pick up birds and other small clutter. the reason why they don't is do to software filters: exclude all contacts below this size and or traveling below this velocity.

That brings up one other point: you're probably aiming for nonspinning parts of any given hab, which to my estimation at least means that any given torus or cylinder hab is going to be infiltrated via industrial and manufacturing elements, or any other part that doesn't need much gravity. I'm not sure if such areas would be more or less watched than any other part of a hab. More on the outside, I'd imagine, than the inside, since it's obviously a target for the raw materials and machinery but mostly automated within. That still brings up the issue of getting inside at all, and doing so without setting off alarms. That's a fairly tall order, I'd think, given it means getting from vacuum to atmosphere, and habitats are going to be very, very alert for anything even resembling a hull breach. Airlocks are going to have a lot of electronic eyes on them, both security and operations feeds for the docking authorities. What other features would you find on the exterior of a hab that an infiltration team would be able to use? Vents, maybe? Actually...thinking on it, the MRG mentioned that vacuum pods tend to have samey looks, so once you're on-site and if you have a good impersonation score, getting in might be less about infiltration and more about having the EP equivalents to a hardhat, clipboard, and determined stride.

Cutting through the hab surface seems like it would set off any hull breach spimes in the outer hull, but not all habs have those I'd imagine. I suspect that for infiltrating most habs, visiting normally or socially infiltrating would be the easier method. I suspect that the Covert Pod is more for getting into ships and potential derelicts rather than habs themselves.

Trappedinwikipedia wrote:

Cutting through the hab surface seems like it would set off any hull breach spimes in the outer hull, but not all habs have those I'd imagine. I suspect that for infiltrating most habs, visiting normally or socially infiltrating would be the easier method. I suspect that the Covert Pod is more for getting into ships and potential derelicts rather than habs themselves.

It depends, honestly, on the local set-up. Monitoring the entire hull's integrity probably takes a lot more investment into sensors than just monitoring for pressure drops. If the pressure on a compartment which is seperated from vacuum by a section of hull drops to 0, you can be safely assured there's a hull breach in that compartment. Installing a layer of sensor lattice to monitor for the exact shape and size of the hull breach would be, by comparison, a hugely lavish use of resources given that monitoring for hull breaches just by monitoring air pressure (something you're going to be doing anyway as part of the environmental monitoring,) is perfectly capable of telling you if the hull's been breached.

I'm assuming the tent would be chameleon cloak-like tech, though it would have to be pretty thickly EM-suppressant to hide you cutting through a hull meant to withstand chunks of rock or metal hitting at a few hundred relative m/s. I can see the resources to monitor the hull's integrety being a huge investement, but given the sheer amount of effort we put into modern Aerospace to check for micro fractures and stress damage, some redundant systems sound like they'd be in place, even if it's nothing more advanced than a backup barometer/temperature rig like a modern humidor set up to an alarm system. Cheaper to fix a small problem than a later larger problem and all that. A possibly more economical system, and one that would be a challenge to circumvent, would be an array of small drones or gnatbots, positioned around the hab so that a dozen or so can view the whole thing, and monitor for impacts. All they'd need would be solar panels, a multi-range EM sensor suite, and an ion drive with a basic AI for position-keeping. Probably cheaper than a hull-wide sensor mesh, though given EP's manufacturing capabilities, a thin layer of metamaterials that act like a huge, flat tripwire may not be terribly expensive either. EDIT: have some time while waiting for a client, so I sketched up what I meant. Your standard triple-stack stanford with four basic rings of Habitat Hull Anomaly Detection (HHAD?)drones [red rings]. [img]http://i.imgur.com/f0mELtU.png?1[/img]

The no-stealth-in-space arguments are pretty solid, but they're based on a lot of assumptions that are not necessarily true -- or at least not always true. I think the bottom line is that stealth is more of a strategic / social engineering / hacking / electronic warfare challenge than it is one of finding a technological approach to hiding one's signature. The challenge is finding the times or creating the windows where the anti-stealthers' assumptions will not be valid. When there will be a gap in coverage, when you are relying on sensors that you do not personally own and might not give you 100% accurate data, when you might be assumed to be something other than what you are, etc.

That's a thought. Is there any way to accurately predict solar flares and other emissions, maybe paying off some of the solar habs? It would be tremendously situational, but that might provide a bit of cover for a physical stealth op. Assuming you can shield yourself.