4 ms·

Why deorbit? It cost a lot of money to get that junk off the planet, surely its more valuable up there for somebody smart to harvest it and reuse it in place.

Sharlin 5y ago
Well, the stuff is there right now, but there’s nobody harvesting them because it’s nowhere near economically viable. Maybe someday in the future, but we can’t just keep polluting the orbits while waiting for that hypothetical day. LEO stuff is going to deorbit due to drag anyway sooner or later, and we very much would like that to be ”sooner”. Higher orbits are stable for a long time, and intentional deorbiting is not feasible anyway due to the amount of delta-v needed. So there are ”graveyard orbits” into which satellites should be moved before they’re out of propellant. Anyway, intercepting and capturing defunct satellites on a large scale would be surprisingly costly because of the large variety of orbital planes involved. Inclination changes are expensive with regard to delta-v!
qayxc 5y ago
It isn't worth collecting. This is Earth orbit, not the ocean or some strip of land. The debris zooms around the planet on all kinds of trajectories and it's immensely difficult to match velocity and direction in order to capture it. It's worse than trying to collect machine gun bullets mid-flight that were fired from a rotating carousel by a guy with shaking hands... Some parts, like spent second rocket stages, present some value because they could be reused as wet-workshops [1]. Material value alone, however, doesn't justify the cost of capture in most cases. [1] https://en.wikipedia.org/wiki/Wet_workshop https://en.wikipedia.org/wiki/Wet_workshop
rcxdude 5y ago
Most of its value is in the energy in its orbit (not in its altitude). But to harvest it to use for something else you would need to change its orbit substantially, which requires even more energy. It would only be worthwhile for large clouds of debris in mostly the same orbit, which tend not to occur.
Cthulhu_ 5y ago
Sounds interesting in a sci fi fashion, but you'd need a lot of equipment in orbit to do so - forges, smelters, welding equipment, and of course laborers to process things. I don't think, all things, challenges and risks considered, that it's viable at this time. Besides, the main problem is in the small fragments, which are very hard to actually catch (safely), let alone reprocess. The bigger pieces of space junk are less of a problem, if only because they can be tracked.
scrose 5y ago
I don’t think most countries would want another country harvesting their ‘abandoned’ space junk :)

Sharlin 5y ago

Well, the stuff is there right now, but there’s nobody harvesting them because it’s nowhere near economically viable. Maybe someday in the future, but we can’t just keep polluting the orbits while waiting for that hypothetical day. LEO stuff is going to deorbit due to drag anyway sooner or later, and we very much would like that to be ”sooner”. Higher orbits are stable for a long time, and intentional deorbiting is not feasible anyway due to the amount of delta-v needed. So there are ”graveyard orbits” into which satellites should be moved before they’re out of propellant. Anyway, intercepting and capturing defunct satellites on a large scale would be surprisingly costly because of the large variety of orbital planes involved. Inclination changes are expensive with regard to delta-v!

qayxc 5y ago

It isn't worth collecting. This is Earth orbit, not the ocean or some strip of land. The debris zooms around the planet on all kinds of trajectories and it's immensely difficult to match velocity and direction in order to capture it. It's worse than trying to collect machine gun bullets mid-flight that were fired from a rotating carousel by a guy with shaking hands... Some parts, like spent second rocket stages, present some value because they could be reused as wet-workshops [1]. Material value alone, however, doesn't justify the cost of capture in most cases. [1] https://en.wikipedia.org/wiki/Wet_workshop https://en.wikipedia.org/wiki/Wet_workshop

rcxdude 5y ago

Most of its value is in the energy in its orbit (not in its altitude). But to harvest it to use for something else you would need to change its orbit substantially, which requires even more energy. It would only be worthwhile for large clouds of debris in mostly the same orbit, which tend not to occur.

Cthulhu_ 5y ago

Sounds interesting in a sci fi fashion, but you'd need a lot of equipment in orbit to do so - forges, smelters, welding equipment, and of course laborers to process things. I don't think, all things, challenges and risks considered, that it's viable at this time. Besides, the main problem is in the small fragments, which are very hard to actually catch (safely), let alone reprocess. The bigger pieces of space junk are less of a problem, if only because they can be tracked.

scrose 5y ago

I don’t think most countries would want another country harvesting their ‘abandoned’ space junk :)