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Are 'parallel orbits' actually possible without active station keeping? (Thinking of Seveneves).

• TeMPOraL 7y ago
  No. The orbital plane must intersect the (bary)center of Earth. If you took that model and placed it to the right of ISS, with matching altitude and velocity vectors, then half the orbital period later, you'd find it somewhere to the left of the station. If you want to keep two things close together in orbit for a while without active stationkeeping, your best bet is placing one ahead or behind of the other. Though in real life, they'll eventually drift their separate ways too, due to lots of small influences like solar pressure, residual air drag, gravitational pull of other bodies in the system, etc.
  • Piskvorrr 7y ago
    Even worse, the actual ISS requires active stationkeeping, making it unreliable w/r/t celestial mechanics alone.
  • usrusr 7y ago
    Wouldn't there be considerable slipstream from the trace atmosphere? Aft, slightly higher than the stations center of mass there should be a point were the slower angular speed of the minimally higher orbit would cancel out with the slipstream effect, until the next stationkeeping burn. I wonder how much it would start spinning from the uneven application of trace atmosphere in that time. Might make a fun public experiment, try getting "the internet" to voice their predictions, kind of like everybody was commenting on the color of the dress. In any case I fully expect a kit to eventually make it up there but I doubt that it will see any EVA.