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dWintermut3 t1_j5xtmlg wrote

Reply to comment by electric_ionland in Why do sample return missions such as OSIRIS-REx use their own reentry vehicles instead of just going to the space station for pickup and return with ISS equipment? by PromptCritical725

now my knowledge of orbital mechanics comes entirely from video games, but couldn't you use a partial aerobrake?

one tactic I often use is to plan a trajectory that has a periapsis that is barely in the atmosphere, just brushing it such that there is only a tiny bit of drag from very thin atmosphere. this acts to lower my periapsis just a bit, the effect being exaggerated by the fact the relative orbital velocity is at maximum at periapsis and minimum at apoapsis. over a few successive orbits I can bleed a significant amount of velocity with minimal heat and stress. I never used this to attempt a rendezvous, though I want to try now, but I do use it to bleed enough speed that a drogue chute is viable to go the rest of the way

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Kantrh t1_j5xwy1v wrote

If you're partially aerobraking you might as well do it fully rather than trying to catch up to the ISS

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Alblaka t1_j5y6ikr wrote

I'd suggest that performing a precise aerobrake in reality might be slightly more difficult than in an abstracted simulation, i.e. due to the simulation always being 100% accurate, whilst any modelling of our actual atmosphere might be less precise.

It's easy to do a full aerobrake, and it's relatively easy to avoid aerobraking. But treading that fine line between might be a bit unfeasible in an unsimulated environment.

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gdshaffe t1_j5ydp8g wrote

I see someone other than me has spent the last drop of their fuel getting that Kerbin periapsis down to 50km or so and just used the "aerobrake 200 times" maneuver to get back home.

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