STS-109

STS-109 (Hubble Servicing Mission 3B 'SM3B') was a Space Shuttle mission that launched from the Kennedy Space Center on 1 March 2002. It was the 108th mission of the Space Shuttle program, the 27th flight of the orbiter Columbia and the fourth servicing of the Hubble Space Telescope. It was also the penultimate mission of the orbiter Columbia before the STS-107 mission, which was destroyed during re-entry in the Columbia disaster. The Hubble Space Telescope (HST) was placed in orbit during mission STS-31 on 25 April 1990. Initially designed to operate for 15 years, plans for periodic service and refurbishment were incorporated into its mission from the start. After the successful completion of the second planned service mission (SM2) by the crew of STS-82 in February 1997, three of the telescope's six gyroscopes failed. NASA decided to split the third planned service mission into two parts, SM3A and SM3B. A fifth and final servicing mission, STS-125 (SM4) launched on 11 May 2009. The work performed during SM4 kept HST in operation through 2025.