NASA's Upper Atmosphere Research Satellite (UARS) was launched in 1991 from the Space Shuttle and was the first multi-instrumented satellite to observe numerous chemical constituents of the atmosphere with a goal of better understanding atmospheric photochemistry and transport. 

Many of these studies centered on the early understanding of ozone photochemistry. At that time, there were open questions as to the details surrounding stratospheric ozone loss, especially with the processes related to the ozone hole above the Antarctic. UARS data were uniquely designed to address those questions.