Nightflyers and Other Stories (original) George R.R. Martin

On a voyage toward the boundaries of the known universe, nine misfit academics seek out first contact with a shadowy alien race.

But another enigma is the Nightflyer itself, a cybernetic wonder with an elusive captain no one has ever seen in the flesh. Soon, however, the crew discovers that their greatest mystery – and most dangerous threat – is an unexpected force wielding a thirst for blood and terror