Starfleet Academy Courses. Subspace Communication: Depending on the actual distance between a vessel and the nearest subspace relay beacon, real-time communication is possible. An example of this is when Starfleet Lieutenant Reginald Barclay contacted the USS Enterprise-E, which was seven light years away from his location on the Jupiter Station, and spoke real-time to the ship's counselor, Commander Deanna Troi. Consult: VOY: "Life Line". Star Trek Starfleet Command | Starfleet Academy