The longest single space shuttle mission lasted 17 days: STS-80 flew for 17 days, 15 hours, and 53 minutes. The mission launched aboard Columbia on November 19, 1996, and landed on December 7 after weather delays.
STS-80 carried five astronauts and deployed two free-flying research spacecraft: the ORFEUS-SPAS II ultraviolet observatory and the Wake Shield Facility-3. Columbia’s crew later retrieved both spacecraft, allowing scientists to examine their instruments and experiments after they had operated independently in orbit.
The mission was planned to include two spacewalks, but both were canceled when problems with the airlock hatch prevented astronauts from exiting. That did not prevent STS-80 from setting the shuttle-duration record. Its elapsed time is often simplified to “17 days,” which is the correct answer when the question asks for the duration in whole days.
STS-80 was also notable for astronaut Story Musgrave, who became the only person to fly aboard all five shuttle orbiters: Challenger, Discovery, Atlantis, Endeavour, and Columbia.