Martin Joseph Fettman (B.S., D.V.M., M.S., Ph.D., Diplomate, ACVP) is an American pathologist and researcher who flew on NASA Space Shuttle mission STS-58 aboard the Space Shuttle Columbia as a Payload Specialist.
Fettman was selected as a NASA payload specialist candidate in December 1991, as the prime payload specialist for Spacelab Life Sciences-2 in October 1992. He then flew on STS-58 in October 1993. Since the flight, he has made over seventy public appearances representing space life sciences research before higher education, medical, veterinary, and lay organizations, and visited over twenty K-12 schools around the United States and Canada. He is a member of the NASA Advisory Council Life and Biomedical Sciences and Applications Advisory Subcommittee.