Crewman Foster was a operations division Starfleet officer who served on board the USS Voyager, under Captain Kathryn Janeway during the ship's mission to the Delta Quadrant during the 2370s.
In 2372, Foster went to sickbay for an analgesic, shortly after stardate 49507.2. (VOY: "Lifesigns")
In 2373, Foster was ordered by Tuvok to take Vel, a member of the terrorist organization Open Sky, to Chakotay so that he could give Chakotay the codes and directions to the Akritirian maximum security detention facility where Tom Paris and Harry Kim were being held. (VOY: "The Chute")
In 2374, Foster was reported on a monitor in sickbay as being one of the crew who was unable to stop dreaming as the result of an alien neurogenic field. (VOY: "Waking Moments")