I've yet to figure out exactly how long the previous planet stays around. Initially, I thought, "Oh, this is easy. If I always go back to the same place, I can just leave things here and pick up where I left off. " Then I stayed too long somewhere else, and it was all wiped out. So, use this "exploit" carefully, I guess, would be my advice.
I played a strategy of bringing everything back to the platform and either processing it on the ground floor or sending it to the factory floor. Of course, YMMV. Like Factorio, there are a ton of different ways to play this mod.