Have to make this quick, as I am sorting out a lot of college stuff. I enjoyed this anime and this particular OP theme had both the signs of a pirate song and it being in space, hence it being called Mouretsu Pirates or Bodacious Space Pirates.
The initial part has that typical rhythm of a pirate type song and an echo-like bit in the middle which has a sort of outer space feel. Anyway enough of my going on I have to get back to sorting out my college work. Enjoy!