alt Hacker NewsForgive my bluntness asking this question: how hard can it be to put a stationary "satellite" as a communication relay next to the moon to bridge the "dark window" with the space craft?
Replies
lexicality • today at 6:25 PM
Orbital mechanics and "next to" don't go together particularly well, so it's not quite as easy as popping something up there.
The Chinese have put Queqiao-1 in the earth-moon L2 point which seems to be working out for them, but I guess the Americans aren't likely to be asking permission to use it.
Insanity • today at 6:19 PM
Well technical difficulty is one piece. Cost and ROI are a different one.
It's doable (and has been done), but is not entirely easy or cheap. Without getting into the orbital mechanics/whys, a "geostationary" orbit around the moon is not available (it exists but is further out than the Hill sphere and not stable). You can park a relay semi-stably at Earth-Moon L2, but still need station-keeping burns. The moon has has a very lumpy gravity field, so any kind of orbit needs station-keeping eventually.
It's just not super worth it.
If you want to look at a mission that did this, see China's Queqiao.