I have wondered it myself, I thought that this was a lame missing link/unexplained link that just didn't make sense. I thought superman didn't need to have a space ship in in space, but I guess I was wrong. But he didn't even bother with a regular ship, but a odd meteor type ship, like the one he arrived in. I think it was more of a returning the way he came type of plot, showing that he was starting over again.