> However, for existing dead satellites & debris that is above atmospheric decay in reasonable times, I wonder if it would actually be more effective/efficient (in terms of cost, delta-V, scheduling, etc.) to 'herd' the junk into a more out-of-the-way location for future use. It seems once on-orbit manufacturing starts, it'd be useful to have a lot o high-quality material up out of the gravity well, and all of that stuff has already had huge investment to get it to orbit in the first place.
Basically none of that is practical. Moving anything in space requires fuel. Changing a satellite's orbit from A to B requires the same amount of fuel as going from B to A. Going from A to B and then back to A takes twice the fuel. If you pick up more mass at B, you actually need more fuel to get back to A. You also need fuel to rendezvous with your fuel depot where you can get all the fuel for these trips.
Every rendezvous has a probability of failure. The more rendezvous you perform the more likely it is something bad will happen. Satellites aren't usually super sturdy structures because they're optimizing for mass. So some satellite herder needs to spend a lot of extra fuel matching the target's spin rate and velocity so capturing it doesn't cause it to break apart.
Then there's the orbital manufacturing. Even if you managed to capture hundreds of satellites and herd them into some holding orbit, you've got a bunch of heterogeneous parts clumped together. You'd need to disassemble a bunch of devices that weren't meant to be disassembled. Even if you get them disassembled they're a bunch of finished packaged parts. They're not going to be reusable so they'd need to be melted down. Now you need smelters and centrifuges and every other chain in recycling materials to base feedstocks.
That's all an absurd level of complexity and danger compared to just de-orbiting a satellite. The costs don't even compare. Your proposal would be phenomenally expensive if it was practical. Satellite clean up is highly impractical and expensive but still orders of magnitude more practical and cheaper than the things you're talking about.
Thanks! I hadn't considered the risks of multiple rendevous maneuvers — probably more risky than shooting some kind of net around the target with a drag sail attached or something.
Like a magnified version of most modern mfg, it just bugs me that the easiest way to deal with failures is to just trash the thing rather than reuse/repair.
Basically none of that is practical. Moving anything in space requires fuel. Changing a satellite's orbit from A to B requires the same amount of fuel as going from B to A. Going from A to B and then back to A takes twice the fuel. If you pick up more mass at B, you actually need more fuel to get back to A. You also need fuel to rendezvous with your fuel depot where you can get all the fuel for these trips.
Every rendezvous has a probability of failure. The more rendezvous you perform the more likely it is something bad will happen. Satellites aren't usually super sturdy structures because they're optimizing for mass. So some satellite herder needs to spend a lot of extra fuel matching the target's spin rate and velocity so capturing it doesn't cause it to break apart.
Then there's the orbital manufacturing. Even if you managed to capture hundreds of satellites and herd them into some holding orbit, you've got a bunch of heterogeneous parts clumped together. You'd need to disassemble a bunch of devices that weren't meant to be disassembled. Even if you get them disassembled they're a bunch of finished packaged parts. They're not going to be reusable so they'd need to be melted down. Now you need smelters and centrifuges and every other chain in recycling materials to base feedstocks.
That's all an absurd level of complexity and danger compared to just de-orbiting a satellite. The costs don't even compare. Your proposal would be phenomenally expensive if it was practical. Satellite clean up is highly impractical and expensive but still orders of magnitude more practical and cheaper than the things you're talking about.