Space Vamps

EREBUS, a small space station travelling to TRAPPIST-1, the main mission was to find out the habitability of the exoplanets. It's not the first of its kind (station or mission) and many have already made it to closer exoplanets. 

Along the journey they are researching the effects of cryo, general effects of humans in long distance space travel, food growing abilities etc. Most of this technology is well known and trusted, but there are innovations needed to be made with it.

The station is supported by an AI called Nyx. It planned to work in cycles of 1 year out of cryo and several years in cyro, whilst travelling at near light speed. This was to monitor effects on the crew, other experiments and to make sure the station was on track, as well as ensure the crew would not have aged drastically by the time they reached TRAPPIST-1. Nyx would monitor trajectory and other systems, and wake whoever was needed to fix anything. 

After one cyro cycle, the station is attacked by a cosmic vampire, it's a mess. Systems damage, crew sucked out into the void. Most are massacred by the vampire. Two survive but are both turned. The station is left to drift, still on course for TRAPPIST. They have all the time in the world now that they're immortal.