The UARS (Upper Atmosphere Research Satellite) is a satellite which was launched by the Discovery space shuttle in 1991 to study the Earth’s atmosphere, particularly the protective ozone layer. It was decommissioned by Nasa in 2005. It is about 35ft long – the size of a bus – and weighs six tonnes.
The 5,900 kg satellite was deployed in 1991 by Space Shuttle Discovery, during the STS-48 mission. The original mission duration was to be three years. UARS originally orbited at an operational altitude of 600 km with an orbital inclination of 57 degrees. In June 2005, 14 years after the satellite’s launch, six of its ten instruments were still operational. UARS was decommissioned in 2005, and a final orbit-lowering burn, followed by the passivation of the satellite’s systems, was performed in early December 2005.
On October 26, 2010, the International Space Station performed a debris-avoidance maneuver in response to a conjunction with this satellite.
The satellite is expected to fall from orbit during the afternoon of September 23, 2011, Eastern Daylight Time. NASA has warned members of the public not to touch any pieces of the spacecraft which may survive the re-entry, urging them to contact local law enforcement authorities.