Millie Hughes-Fulford (December 21, 1945 – February 4, 2021) was an American astronaut, medical investigator, molecular biologist, and professor.

She was the first woman to launch into space who was not a professional astronaut but a working scientist. Originally selected by NASA in 1983 to train for a science-dedicated space shuttle mission, her launch was delayed by the 1986 Challenger tragedy. But finally lifting off on the space shuttle Columbia on June 5, 1991, she became the first female payload specialist to enter orbit and a member of the first crew to include three women.

Aboard STS-40 Spacelab Life Sciences (SLS 1), she was part of the first Spacelab mission dedicated to biomedical studies. The SLS-1 mission flew over 3.2 million miles in 146 orbits and its crew completed over 18 experiments during a nine-day period, bringing back more medical data than any previous NASA flight. 

Hughes-Fulford was a Professor at the University of California Medical Center at San Francisco where she continued her research until her death in 2021.