4 ms·

>Higher orbit junk is what really matters, and will require much more delta-v to reach, and then again to de-orbit after "docking". Wait, why? The lower orbit

• jmcomets 5y ago
  With my very basic understanding of orbital mechanics, higher orbits require more dV simply because it's further from Earth. The more interesting bit is that subtle orbital adjustments require much less dV in higher orbits than in lower ones. I like to think of it like pushing a barrel uphill: it takes more effort if the slope is steep, but then once it's up there, it's a lot easier to get the barrel moving downhill. Anyways, the "de-orbit" cost follows the same rule of higher being more costly in dV, the big difference with an ascension being that the atmosphere slowing you down is what you want (aerobraking is the word, I think?). So the difference in dV between a high orbit and a low orbit descent isn't proportionate to that of the ascent, if that makes any sense.
• Ajedi32 5y ago
  Low orbit stuff gets naturally de-orbited after a few years/decades by stray air molecules from the Earth's atmosphere, so there's little point to manually cleaning it. Debris in higher orbits can take centuries or millennia to naturally de-orbit, so manual cleaning there makes more sense.