It would likely be nearly impossible to return it to Earth. Moving it into a graveyard orbit far above the current altitude is a possibility, but it would be very expensive, and the station...
It would likely be nearly impossible to return it to Earth. Moving it into a graveyard orbit far above the current altitude is a possibility, but it would be very expensive, and the station requires continuous habitation to operate.
I’d assumed it would remain in space. I guess that’s one of the reasons I thought about having it as a landmark vs a museum (at least for now), would be theoretically you could handle most issues...
I’d assumed it would remain in space. I guess that’s one of the reasons I thought about having it as a landmark vs a museum (at least for now), would be theoretically you could handle most issues remotely if it was a passive landmark.
Just to put my remarks into context, the ISS's average altitude is around 400km (370 to 460 decaying at 2km/mo), while the traditional disposal orbit, where the orbital decay from drag is...
Just to put my remarks into context, the ISS's average altitude is around 400km (370 to 460 decaying at 2km/mo), while the traditional disposal orbit, where the orbital decay from drag is essentially eliminated, is closer to 40,000km - 100 times further away! The ISS is very massive, and without the Shuttle, Zvezda and Soyuz are the only craft we currently have capable of actually propelling the ISS on a routine basis. Neither of these systems could boost the station the whole way, which means designing a mission with multiple boost maneuvers, refuelings, and drastic attitude changes. This would be difficult, dangerous, and expensive, and while I would absolutely love to see the ISS preserved for future generations, there is no way any one nation would have the political will to pull it off. Furthermore, it's very unlikely that Russia would be interested in cooperating with the US on this, at least in the near future.
In light of all that, I would think that "preserving" it in VR would be a great alternative, as I think there is already a game for this too. Maybe just with more details now.
In light of all that, I would think that "preserving" it in VR would be a great alternative, as I think there is already a game for this too. Maybe just with more details now.
I'm not sure 40000km is your only option here. That one is chosen because it is just above geosynchronous orbit (GEO). I.e. we chose it because we want to put old satellites from GEO there. (It is...
I'm not sure 40000km is your only option here. That one is chosen because it is just above geosynchronous orbit (GEO). I.e. we chose it because we want to put old satellites from GEO there. (It is above rather than below GEO because that way neither signals nor satellites have to pass through it.) It is not necessary to go out that far for drag to not matter. I'd wager that a few 1000 km is easily enough to make the drag not matter. (Justification: Atmospheric density decays exponentially with a half-life of a few km. If at 400km it matters enough to justify re-boosting every few months or years, at 1000km, re-boosting would only be required, what, every 1000 years or so? Though I admit the atmosphere need not behave as I demand it.)
That said, it's still a big effort. According to wikipedia, you'd need 7.5t of fuel ($210 million) for 24 km of altitude boost. That gets cheaper the further up you already are, also cheaper if you use a proper transfer orbit, but it's good enough for our purposes. So that's 30t for 100km of altitude, and we need several times that. So you're looking at something like a few billion dollars or so, just to put it into an orbit where we can't maintain it and can't visit it. By the time we are ready for mass space travel, I'm not sure how much will be left. It's not exactly designed to be left alone; it needs frequent maintenance and (I'd guess) resupply of coolant fluids. If temperature control fails, I don't know what that would do to the station.
You also have to consider the van Allen belts; anywhere between 1000km and 12000km you'd be hammering your museum piece with protons exceeding 100MeV on the regular. Its electronics would almost...
at 1000km, re-boosting would only be required, what, every 1000 years or so?
You also have to consider the van Allen belts; anywhere between 1000km and 12000km you'd be hammering your museum piece with protons exceeding 100MeV on the regular. Its electronics would almost certainly fall apart after a few years at most, and you'd be facing thin-film degradation after a decade. I certainly wouldn't step foot on station after that.
But, yeah, I think even if we could, say, attach a huge fuel tank and periodically reboost it at 850km or something, the political will just isn't there, which is really sad.
Maybe some university could cook up a fairly cheap continuously firing ion thruster module?
Paging /u/nukeman for obvious reasons. Does proton radiation actually activate anything? My thinking is it just knocks a bunch of atoms and electrons around, destroying molecules, causing cancer,...
You also have to consider the van Allen belts; anywhere between 1000km and 12000km you'd be hammering your museum piece with protons exceeding 100MeV on the regular. Its electronics would almost certainly fall apart after a few years at most, and you'd be facing thin-film degradation after a decade. I certainly wouldn't step foot on station after that.
Does proton radiation actually activate anything? My thinking is it just knocks a bunch of atoms and electrons around, destroying molecules, causing cancer, all that good stuff, but once its energy is spent it just yoinks an electron and fucks off as a happy little hydrogen atom. The only way I can imagine that activating a nucleus is if it actually knocks a neutron out of a nucleus or gets absorbed into a nucleus. My intuition tells me You'd need a lot more energy to achieve that, but I don't know.
The ion thruster sounds like an option, but those things aren't free either and you need a huge power supply (granted) and some amount of fuel. Ion thrusters are many times more efficient, which means you need many times less fuel. Many times less than "stupidly too much" might still be too much, don't know. The numbers are all there to calculate how much thrust such a contraption would need (24km yearly altitude decay, 400 tons or so, 400km orbit above earth), so the math can be done if anyone is interested. Considering the 400 tons and the (original) 30t of fuel per year, I'd suspect it's a lot.
Also, quick ballpark estimate of the fuel costs: Current Xenon thrusters are about 10x more efficient, so you'd need 3t of xenon per year. That's still a lot. (This is cobbled together from different, possibly inconsistent, sources, so it might be off by a lot)
I actually don't know, but that's not what I meant; the proton flux in the lower belt is well known to cause problems with electronics, and a high proton flux can destroy thin metal junctions...
Does proton radiation actually activate anything?
I actually don't know, but that's not what I meant; the proton flux in the lower belt is well known to cause problems with electronics, and a high proton flux can destroy thin metal junctions through simple galvanic corrosion as it imparts charge to one side of an object preferentially. This is especially bad in space, because there is no atmospheric oxygen to replace the oxide coating that keeps metals separate and insulates them; once galvanic corrosion begins, it continues unimpeded, and can lead to cold welding in addition.
And, yeah, the xenon thruster would definitely not be free. But 3t of fuel is much, much more reasonable; two flights of Crew Dragon could bring up a thruster module and sufficient fuel, as opposed to order of a dozen flights.
Based on my understanding it does not directly activate materials in a manner similar to neutrons, no. It does something similar to what you are saying: cause knock-on effects, stirring up alpha...
Based on my understanding it does not directly activate materials in a manner similar to neutrons, no. It does something similar to what you are saying: cause knock-on effects, stirring up alpha particles, neutrons, and other particles.
I wonder how much it would cost to preserve it as a museum/historic landmark?
It would likely be nearly impossible to return it to Earth. Moving it into a graveyard orbit far above the current altitude is a possibility, but it would be very expensive, and the station requires continuous habitation to operate.
I’d assumed it would remain in space. I guess that’s one of the reasons I thought about having it as a landmark vs a museum (at least for now), would be theoretically you could handle most issues remotely if it was a passive landmark.
Just to put my remarks into context, the ISS's average altitude is around 400km (370 to 460 decaying at 2km/mo), while the traditional disposal orbit, where the orbital decay from drag is essentially eliminated, is closer to 40,000km - 100 times further away! The ISS is very massive, and without the Shuttle, Zvezda and Soyuz are the only craft we currently have capable of actually propelling the ISS on a routine basis. Neither of these systems could boost the station the whole way, which means designing a mission with multiple boost maneuvers, refuelings, and drastic attitude changes. This would be difficult, dangerous, and expensive, and while I would absolutely love to see the ISS preserved for future generations, there is no way any one nation would have the political will to pull it off. Furthermore, it's very unlikely that Russia would be interested in cooperating with the US on this, at least in the near future.
In light of all that, I would think that "preserving" it in VR would be a great alternative, as I think there is already a game for this too. Maybe just with more details now.
We'll also have that Tom Cruise movie eventually that I think will feature some of the ISS.
I'm not sure 40000km is your only option here. That one is chosen because it is just above geosynchronous orbit (GEO). I.e. we chose it because we want to put old satellites from GEO there. (It is above rather than below GEO because that way neither signals nor satellites have to pass through it.) It is not necessary to go out that far for drag to not matter. I'd wager that a few 1000 km is easily enough to make the drag not matter. (Justification: Atmospheric density decays exponentially with a half-life of a few km. If at 400km it matters enough to justify re-boosting every few months or years, at 1000km, re-boosting would only be required, what, every 1000 years or so? Though I admit the atmosphere need not behave as I demand it.)
That said, it's still a big effort. According to wikipedia, you'd need 7.5t of fuel ($210 million) for 24 km of altitude boost. That gets cheaper the further up you already are, also cheaper if you use a proper transfer orbit, but it's good enough for our purposes. So that's 30t for 100km of altitude, and we need several times that. So you're looking at something like a few billion dollars or so, just to put it into an orbit where we can't maintain it and can't visit it. By the time we are ready for mass space travel, I'm not sure how much will be left. It's not exactly designed to be left alone; it needs frequent maintenance and (I'd guess) resupply of coolant fluids. If temperature control fails, I don't know what that would do to the station.
You also have to consider the van Allen belts; anywhere between 1000km and 12000km you'd be hammering your museum piece with protons exceeding 100MeV on the regular. Its electronics would almost certainly fall apart after a few years at most, and you'd be facing thin-film degradation after a decade. I certainly wouldn't step foot on station after that.
But, yeah, I think even if we could, say, attach a huge fuel tank and periodically reboost it at 850km or something, the political will just isn't there, which is really sad.
Maybe some university could cook up a fairly cheap continuously firing ion thruster module?
Paging /u/nukeman for obvious reasons.
Does proton radiation actually activate anything? My thinking is it just knocks a bunch of atoms and electrons around, destroying molecules, causing cancer, all that good stuff, but once its energy is spent it just yoinks an electron and fucks off as a happy little hydrogen atom. The only way I can imagine that activating a nucleus is if it actually knocks a neutron out of a nucleus or gets absorbed into a nucleus. My intuition tells me You'd need a lot more energy to achieve that, but I don't know.
The ion thruster sounds like an option, but those things aren't free either and you need a huge power supply (granted) and some amount of fuel. Ion thrusters are many times more efficient, which means you need many times less fuel. Many times less than "stupidly too much" might still be too much, don't know. The numbers are all there to calculate how much thrust such a contraption would need (24km yearly altitude decay, 400 tons or so, 400km orbit above earth), so the math can be done if anyone is interested. Considering the 400 tons and the (original) 30t of fuel per year, I'd suspect it's a lot.
Also, quick ballpark estimate of the fuel costs: Current Xenon thrusters are about 10x more efficient, so you'd need 3t of xenon per year. That's still a lot. (This is cobbled together from different, possibly inconsistent, sources, so it might be off by a lot)
You gotta love the SciFi look though.
I actually don't know, but that's not what I meant; the proton flux in the lower belt is well known to cause problems with electronics, and a high proton flux can destroy thin metal junctions through simple galvanic corrosion as it imparts charge to one side of an object preferentially. This is especially bad in space, because there is no atmospheric oxygen to replace the oxide coating that keeps metals separate and insulates them; once galvanic corrosion begins, it continues unimpeded, and can lead to cold welding in addition.
And, yeah, the xenon thruster would definitely not be free. But 3t of fuel is much, much more reasonable; two flights of Crew Dragon could bring up a thruster module and sufficient fuel, as opposed to order of a dozen flights.
Based on my understanding it does not directly activate materials in a manner similar to neutrons, no. It does something similar to what you are saying: cause knock-on effects, stirring up alpha particles, neutrons, and other particles.