Upper Atmosphere Research Satellite between positions downrange, generally northeast of this position. 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
Greenhouse effect transparent (because the main constituents—, , and Ar—are not able to directly absorb or emit infrared radiation), intermolecular collisions cause the energy absorbed and emitted by the greenhouse gases to be shared with the other, non-IR-active, gases. By their percentage contribution to the greenhouse effect on Earth the four major gases are: It is not possible to assign a specific percentage to each gas because the absorption and emission bands of the gases overlap (hence the ranges given above). Clouds also absorb and emit infrared radiation and thus affect the radiative properties of the atmosphere. Strengthening of the greenhouse effect