You know I'm right.

Vampires in space would be a really stupid idea for a story.

Think about it for a moment. Contemplate my statement.

Still don't know why? I'll tell you why.

Vampires in space would always be asleep, or always awake, or at their most dynamic, a lot like narcoleptics. The latter could be interesting, but would make plot advancement difficult, because, well, you know, they'd fall asleep randomly, and probably in the middle of a vital conversation. Without the planetary surface to block them from the sun, they would be dependent on the hull of the ship. Forget windows. They'd have to view the void from cameras, if indeed they could be awake at all. No one's really sure what makes vampires go to sleep when the sun bursts over the horizon, but it seems to affect them whether they're indoors or out, and assuming that at any given moment they would be near a star, aka a sun, they could fall asleep at any moment, unless they were waaaay out of any planetary system.. and that's boring. Ooo, vampires in an enclosed, windowless boat with nothing around them... fascinating.

It would make a great satire, though.