I am sure they are just following the Star Trek example.

I liked the second episode better than the first. I think it might turn out to be good enough that I will be disappointed when Fox bails on it after one season.

Speaking of Navy ranks ... I once worked with a guy who had enlisted in the Navy, but later became an officer in the Army. Because of his Navy experience, he got assigned to work on a Navy base. He was a Captain at the time and said that he was treated really well on the Navy base - much better than he would have at an Army post.