Louis Ten Eyck Thompson (October 24, 1891 in South Haven, Michigan – December 13, 1978); known as Dr. Tommy) was an American physicist interested in thermodynamics and ballistics and as an expert working for the United States Navy from 1920 to 1954. He was the first technical director at the Naval Ordnance Test Station in California, where he was involved in work on the Manhattan Project, helping design the "gun" used to initiate nuclear explosives, and most involved in the development of rockets for naval and marine fighter aircraft.