Upper Atmosphere Research Satellite Upper Atmosphere Research Satellite The Upper Atmosphere Research Satellite (UARS) was a NASA-operated orbital observatory whose mission was to study the Earth’s atmosphere, particularly the protective ozone layer. The satellite was deployed from Space Shuttle "Discovery" during the STS-48 mission on 15 September 1991. It entered Earth orbit at an operational altitude of , with an orbital inclination of 57 degrees. The original mission duration was to be only three years, but was extended several times. When the mission finally ended in June 2005 due to funding cuts, 14 years after the satellite's launch, six of its ten instruments were
Extraterrestrial atmosphere exoplanet known to have a relatively cloud-free atmosphere and, as well, the first time molecules of any kind have been found, specifically water vapor, on such a relatively small exoplanet. The presence of molecular oxygen () may be detectable by ground-based telescopes, and it can be produced by geophysical processes, as well as a byproduct of photosynthesis by life forms, so although encouraging, is not a reliable biosignature. In fact, planets with high concentration of in their atmosphere may be uninhabitable. Abiogenesis in the presence of massive amounts of atmospheric oxygen could be difficult because early organisms relied on the