What is sts 15?

STS-15 was the fifteenth mission of NASA's Space Shuttle program. The mission was launched on March 13, 1985, and lasted for seven days. The crew consisted of four members: Commander Robert C. "Bob" Springer, Pilot Thomas D. Akers, and Mission Specialists James F. Buchli and David C. "Dave" Leestma.

The primary objective of the mission was to deploy the second in a series of Tracking and Data Relay Satellites (TDRS-B) into geostationary orbit. In addition to deploying the satellite, the crew conducted a number of experiments related to medical research, materials processing, and Earth observations. They also tested several technologies and procedures related to the operation of the Space Shuttle.

STS-15 was the first shuttle mission to feature an all-military crew, with all four crew members having previous military service. The mission was notable for the first use of the SPAS-01 satellite deployment and retrieval system, which allowed the crew to deploy and retrieve small payloads from the cargo bay while in orbit.

STS-15 was successful in achieving its objectives and returned to Earth on March 20, 1985, landing at Edwards Air Force Base in California. The mission marked another successful step in the development of the Space Shuttle program and the deployment of the TDRS satellite network, which continues to provide critical communications support for NASA's missions to this day.