I can't remember the details very clearly because I read it many years ago, but he needs to fix his stuff. He has a repeating day, I think, and keeps meeting a version of himself from a different time. Every day there is a new version and he is trying to help himself fix the ship.
For some reason the name "Lev" is also in my mind when I try to remember this story. I don't know if the character was Lev or, if I am not thinking about Asimov, the author was named Lev.