The Microwave Limb Sounder (MLS) was one of ten scientific instruments on the Upper Atmospheric Research Satellite (UARS), a NASA project operative from 1991-2005. The satellite's suite of instruments researched the “greenhouse effect” (the impact of increased CO2 concentrations in the atmosphere) and the ozone hole over Antarctica. A central element of NASA's "Mission to Planet Earth", UARS provided critical data on the chemical and physical interactions between Earth's upper and lower strata of atmosphere.
The MLS's Processing Board/Filter Bank processed data received through the Ghz Receiver, looking for the spectra signatures of key chemicals, such as chlorine monoxide, a molecule that breaks down and depletes atmospheric ozone.
NASA transferred this object to the museum in 2016.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.