My dad often refers to this short story, and complains that he can't remember where he read it. He probably saw it in the 1970s or 1980s.

It's about two astronauts who have crashed their ship and are sliding around the inside of an enormous crater, which is a nearly-frictionless bowl. As they slide back and forth up to the lip of the crater, they can't quite reach the edge. They have no way to add to their momentum, and are very gradually swinging in smaller and smaller arcs.

Eventually, they realise that one of them can push against the other to create more momentum, but that means the other will lose momentum and be trapped forever; one of them has to betray the other, or offer themselves as sacrifice.

Unfortunately, this is a second-hand telling of the plot, but he has brought it up in every sci-fi discussion we've had over dinner for over twenty years. I don't think I can go another Christmas hearing the story over again. Any ideas what he's referring to?