The Microwave Limb Sounder (MLS) experiments measure naturally-occurring microwave thermal emission from the limb (edge) of Earth's atmosphere to remotely sense vertical profiles of atmospheric gases, temperature, pressure, and cloud ice. The overall objective of these experiments is to provide information that will help improve our understanding of Earth's atmosphere and global change.
The first MLS experiment in space (UARS MLS) was operational on NASA's Upper Atmosphere Research Satellite (UARS) from Sept 1991 until March 2000.
The second (MLS) is on the NASA Earth Observing System (EOS) Aura mission launched 15 July 2004. As of early 2021, more than 16 years since launch, Aura MLS data have been used in more than 1100 peer-reviewed scientific publications, including many in high-profile journals. These papers describe research into ozone layer recovery, climate change, air quality, and the many interactions among these topics.