|
Post by Easy on Mar 1, 2017 15:02:24 GMT
For clarification I am not trying to have a stealth in space discussion. I am instead wanting to numerically express how observable CoDE ships are and what telescopes would be required to detect and track.
I hope to have a new equation ready for you tonight that lets you input a temperature and frequency band and output what percentage of that total wattage is within that band. The problem is the equations I have give the square meter power emitted a steradian per Hertz. Also I have to make it a CDF function to get the bands so I need time to remember my maths.
|
|
|
Post by Enderminion on Mar 1, 2017 15:08:18 GMT
Micro recon drones are everywhere Easy it would be difficult to spot all of the recon drones and fix them and you would never be sure you nailed all of them, these drones backed up by 10+m telescopes in orbit around friendly bodies means that you can't stealth anywhere without all other factions and major mega-corps spotting you and selling that data to those who can't
|
|
|
Post by Easy on Mar 1, 2017 15:32:15 GMT
Micro recon drones are everywhere Easy it would be difficult to spot all of the recon drones and fix them and you would never be sure you nailed all of them, these drones backed up by 10+m telescopes in orbit around friendly bodies means that you can't stealth anywhere without all other factions and major mega-corps spotting you and selling that data to those who can't I don't know what you mean by a micro recon drone unless I know the radiator temperatures and wattage, the cross section and hull emissivity. I don't know what you mean about sensors without knowing the frequency band and aperture size, nor the limitations of the actual photoreceptors and exposure time. I expect sensor nets to be capable of basic military priorities and safe navigation of civilian traffic. So the sensors will be good enough by design. So let's determine the actual needs of this sensor system including the wide angle detectors and the higher resolution narrow angle used for identification and analysis.
|
|
|
Post by caiaphas on Mar 1, 2017 17:02:12 GMT
Micro recon drones are everywhere Easy it would be difficult to spot all of the recon drones and fix them and you would never be sure you nailed all of them, these drones backed up by 10+m telescopes in orbit around friendly bodies means that you can't stealth anywhere without all other factions and major mega-corps spotting you and selling that data to those who can't I don't know what you mean by a micro recon drone unless I know the radiator temperatures and wattage, the cross section and hull emissivity. I don't know what you mean about sensors without knowing the frequency band and aperture size, nor the limitations of the actual photoreceptors and exposure time. I expect sensor nets to be capable of basic military priorities and safe navigation of civilian traffic. So the sensors will be good enough by design. So let's determine the actual needs of this sensor system including the wide angle detectors and the higher resolution narrow angle used for identification and analysis. Just off the top of my head, the main limitation for the wide-angle detectors is going to be how much coolant you can pack onboard (I recall that this was an issue with WISE), since obviously if your mirror is warmer than the things you're looking for then you're not going to see a bloody thing in the infrared. That'll likely be most of the payload mass, unless you can stick them in easily-accessible orbits for maintenance purposes, which is a bad idea. Second major limitation that you'll be looking at is FOV, which'll determine the second major fraction of payload mass, the mirror size and aperture size. For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. EDIT: and you'll want your wide-angle early-warning detectors to operate in the infrared to avoid too many false-positives, because a warship or fleet lighting up their drives or something is going to be veeeeeeeeeery noticable as compared to Fred the Space Trucker making his Hohmann transfer burn for Ceres.
|
|
|
Post by newageofpower on Mar 1, 2017 17:14:30 GMT
For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. Don't forget the XRay active scanner for the assholes cryocooling their ship.
|
|
|
Post by Easy on Mar 1, 2017 17:21:14 GMT
I don't know what you mean by a micro recon drone unless I know the radiator temperatures and wattage, the cross section and hull emissivity. I don't know what you mean about sensors without knowing the frequency band and aperture size, nor the limitations of the actual photoreceptors and exposure time. I expect sensor nets to be capable of basic military priorities and safe navigation of civilian traffic. So the sensors will be good enough by design. So let's determine the actual needs of this sensor system including the wide angle detectors and the higher resolution narrow angle used for identification and analysis. Just off the top of my head, the main limitation for the wide-angle detectors is going to be how much coolant you can pack onboard (I recall that this was an issue with WISE), since obviously if your mirror is warmer than the things you're looking for then you're not going to see a bloody thing in the infrared. That'll likely be most of the payload mass, unless you can stick them in easily-accessible orbits for maintenance purposes, which is a bad idea. Second major limitation that you'll be looking at is FOV, which'll determine the second major fraction of payload mass, the mirror size and aperture size. For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. lampblack or a rough and dark hull is already going to have decent properties approaching a black body. You'll still get some reflection but more of the sunlight will be converted to heat. Assuming the coating is an insulator it would radiate at whatever solar irradiance it received. Hull heating will not be uniform as irradiance changes with angle of incidence. Again the goal is to describe mathmaticaly the minimum requirements of a sensor for each role. I accept that such a sensor can exist.
|
|
|
Post by Enderminion on Mar 1, 2017 17:22:18 GMT
For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. Don't forget the XRay active scanner for the assholes cryocooling their ship. By X-ray scanner you mean "oops I nuked your ship"
|
|
|
Post by caiaphas on Mar 1, 2017 18:01:57 GMT
For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. Don't forget the XRay active scanner for the assholes cryocooling their ship. I figure that that's going to be a non-issue. If you're carrying around cryogenic coolant and just letting it boil off, then that sets an upper limit to how long you can stay cooled before all of it's boiled off and you show up, and, not, I suspect, a high one, since it's going to cut sharply into your mass budget. If you're using heat pumps, that leaves you with two issues; first, how are you dealing with the waste heat from the heat pumps (the answer is going to involve radiators on some level), and second, how are you hiding that waste heat from enemy sensors?
|
|
|
Post by Enderminion on Mar 1, 2017 18:17:03 GMT
Don't forget the XRay active scanner for the assholes cryocooling their ship. I figure that that's going to be a non-issue. If you're carrying around cryogenic coolant and just letting it boil off, then that sets an upper limit to how long you can stay cooled before all of it's boiled off and you show up, and, not, I suspect, a high one, since it's going to cut sharply into your mass budget. If you're using heat pumps, that leaves you with two issues; first, how are you dealing with the waste heat from the heat pumps (the answer is going to involve radiators on some level), and second, how are you hiding that waste heat from enemy sensors? Heat sinks, they boil off at sub 3k temps also providing very low acceleration
|
|
|
Post by newageofpower on Mar 1, 2017 18:27:22 GMT
Don't forget the XRay active scanner for the assholes cryocooling their ship. By X-ray scanner you mean "oops I nuked your ship" Nukes are way too expensive to waste one on every sensor ghost. caiaphasRe: Hydrogen steamer thread.
|
|
|
Post by Enderminion on Mar 1, 2017 18:33:28 GMT
By X-ray scanner you mean "oops I nuked your ship" Nukes are way too expensive to waste one on every sensor ghost. caiaphas Re: Hydrogen steamer thread. you CAN'T count on someone being rational
|
|
|
Post by caiaphas on Mar 1, 2017 18:41:06 GMT
Just off the top of my head, the main limitation for the wide-angle detectors is going to be how much coolant you can pack onboard (I recall that this was an issue with WISE), since obviously if your mirror is warmer than the things you're looking for then you're not going to see a bloody thing in the infrared. That'll likely be most of the payload mass, unless you can stick them in easily-accessible orbits for maintenance purposes, which is a bad idea. Second major limitation that you'll be looking at is FOV, which'll determine the second major fraction of payload mass, the mirror size and aperture size. For the high-res "what-the-heck-was-that" satellites I figure you'd want to run with a mix of optical and infrared, optical to limit in-orbit maintenance, infrared in case some absolute bastard paints their ship in Vantablack. lampblack or a rough and dark hull is already going to have decent properties approaching a black body. You'll still get some reflection but more of the sunlight will be converted to heat. Assuming the coating is an insulator it would radiate at whatever solar irradiance it received. Hull heating will not be uniform as irradiance changes with angle of incidence. Again the goal is to describe mathmaticaly the minimum requirements of a sensor for each role. I accept that such a sensor can exist. Well, I found a photoreceiver that operates up to 2.2 micrometers with about two seconds of Googling, and there's one linked in the bottom of that page that works down to 800 nm, so finding photoreceivers to cover the desired bandwidth is going to be a non-issue. The necessary FOV is going to depend on a lot of factors, but I think the most relevant ones would be how much of the sky are you surveying, the average time it takes enemy warships to perform a transfer burn, how many sats you have (which cuts down on the amount of sky you need to survey per satellite), how quickly you can turn your sat with reaction wheels (dependent on its shape and its mass, itself largely dependent on how much coolant you need to haul along and the size of the mirror you need to increase the signal to above the receiver's sensitivity, which itself is dependent on what wavelength you expect the enemy ships to be radiating most brightly in; if they're radiating mostly at 800 nm, for example, and your receivers measure at 1 mm, then unless your mirror is larger than necessary the signal might not register. Increasing the bandwidth at which you observe should help, but as far as I can remember receivers measure at a specific wavelength dictated by their material properties, so there's no guanrantee that you'll have a receiver for the specific wavelength the enemy ship is radiating most strongly at), and, of course, how large you can afford to make the apeture. Larger scopes means more mass to push around. And I don't think a VantaShip would just radiate at whatever solar irradiance it receives, it also needs to dump waste heat from its reactors/batteries/hamster in a wheel. That's going to raise the energy it needs to dump not insignificantly.
|
|
|
Post by caiaphas on Mar 1, 2017 18:42:25 GMT
By X-ray scanner you mean "oops I nuked your ship" Nukes are way too expensive to waste one on every sensor ghost. caiaphasRe: Hydrogen steamer thread. I read it and a couple theoretical engineering docs concerning it, and frankly, the people pointing out the issues with it were more convincing than the people arguing in support of it.
|
|
rgm79
New Member
Posts: 15
|
Post by rgm79 on May 31, 2018 11:17:04 GMT
Micro recon drones are everywhere Easy it would be difficult to spot all of the recon drones and fix them and you would never be sure you nailed all of them, these drones backed up by 10+m telescopes in orbit around friendly bodies means that you can't stealth anywhere without all other factions and major mega-corps spotting you and selling that data to those who can't 3 MT yield nuke blast at 10 9 m from epicenter will produce near 10 -3 J/m2 or 1000 W/m2 (as I remember, nuklear blast tekes ~1 mikrosecond). Near 30 % of this energy will be in visible light and IR and will concentrate on CCD matrix by telescope optic. And what will happen whith sensor which can detect 10 -11 W/m2 after this? Firstly I think aboul laser drones which shoot randomly into celestial sphere, but after taken into account laser, poverplant and reactor efficiency I understand that nuke will consume much less fission materials.
|
|