2. The “do” Jesus was talking about clearly is not something an astronaut would have to “do”, even if he would be gone for years.
So to summarize, biblical Christianity does have something to “do” but it "is not something an astronaut would have to “do”.
Is it something people on, say, maybe, Earth would have to do?
No. That is the point. We are encouraged to pray. If you call that a “do”, he could do that in space. We are encouraged to understand the Scriptures. He could do that in space. We are encouraged to trust Jesus. He could do that in space. Anything of any consequence that believers are encouraged to “do”, he could do from space...except for all the ritualistic traditions foisted on the sheeple by Rome. Those definitely need a whole entourage of folks to prop up. I mean, who will sing, “I can play dominos better than you can.” for the guy so he feels forgiven?