STS-39 was the 39th mission of NASA's Space Shuttle program and the ninth flight of the Space Shuttle Discovery. It was launched on April 28, 1991, and completed its mission on May 6, 1991.
The primary objectives of STS-39 were to deploy a classified Department of Defense (DOD) payload and to perform a variety of military and scientific experiments. The mission was also notable for being the first shuttle mission to include a spacewalk by a female astronaut, Kathryn C. Thornton.
The STS-39 mission patch is a circular emblem that represents the mission and its crew. It typically includes the mission name, the names of the astronauts, and symbols or images that are relevant to the mission. The design of the STS-39 mission patch was created by the crew and approved by NASA. It is a tradition for each Space Shuttle mission to have its own unique mission patch, which is worn by the astronauts during the mission and is also used to promote the mission to the public.