STS-82 was the 22nd flight of the Space Shuttle Discoveryand the 82nd mission of the Space Shuttle programme. It was NASA's second mission to service the Hubble Space Telescope, during which Discovery's crew repaired and upgraded the telescope's scientific instruments, increasing its research capabilities. Discovery launched from Kennedy Space Centre Florida, on 11 February 1997, returning to Earth on 21 February 1997 at Kennedy Space Centre.

The STS-82 mission was the second in a series of planned servicing missions to the orbiting Hubble Space Telescope ("HST"), which had been placed in orbit on 24 April 1990 by Discovery during STS-31. The first servicing mission was done by Space Shuttle Endeavour on STS-61. Work performed by Discovery's crew significantly upgraded the scientific capabilities of the HST and helped to keep the telescope functioning smoothly until the next scheduled servicing missions, which were STS-103 in 1999 and STS-109 in 2002.

On the third day of the mission, Discovery's seven-member crew conducted the first of four spacewalks (also called Extra-vehicular Activities or "EVAs") to remove two older instruments and install two new astronomy instruments, as well as perform other servicing tasks. The two older instruments being replaced were the Goddard High Resolution Spectrograph and the Faint Object Spectrograph, exchanged for the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), respectively.

Space shuttle discover lands on STS-82.
STS-82 landing
In addition to installing the new instruments, astronauts replaced other existing hardware with upgrades and spares. Hubble received a refurbished Fine Guidance Sensor, an optical device used to provide pointing information for the telescope and as a scientific instrument for astrometric science. The Solid State Recorder (SSR) replaced one of HST's reel-to-reel tape recorders. The SSR provides much more flexibility than a reel-to-reel recorder and can store ten times more data. One of Hubble's four Reaction Wheel Assemblies (RWA) -- part of the telescope's Pointing Control Subsystem—was replaced with a refurbished spare. The RWAs use angular momentum to move and maintain the telescope in a desired position. The wheel axes are oriented so that the telescope can provide science with only three wheels operating, if required. Study of the returned mechanism provided a rare opportunity to study equipment that had undergone long-term service (7 years) in space, particularly for the effects of vacuum on lubricants which were found to be in 'excellent condition'.