Mous began his 51-year career at JPL, initially examining the shock waves anticipated as a space capsule reentered Earth’s atmosphere. Soon, he was examining other aspects of the atmosphere and working on methods to derive atmospheric information from the radiation received by satellite-based instrumentation.
Among Mous’s heralded scientific and engineering accomplishments were his development in the late 1960s of an exact mathematical method for the inverse solution of the radiative transfer equation and his applications of that method to deriving atmospheric temperature and water vapor profiles. This “Relaxation Method” was subsequently widely used for obtaining satellite-based profiles of atmospheric temperature and composition not just for Earth’s atmosphere but also for the atmospheres of Venus, Mars, and Jupiter. Later, in the 1970s, Mous formulated a multispectral approach to remote sensing in the presence of clouds, incorporating both infrared and microwave data. In 1980, Mous and others used his equations to generate the first satellite-based global distribution of Earth’s surface temperature, using data from the High Resolution Infrared Radiation Sounder and the Microwave Sounding Unit. Many additional uses followed.
By this time Mous had proposed what was to become the Atmospheric Infrared Sounder (AIRS), a remarkable satellite instrument that was to dominate much of the next 30 years of his scientific and engineering career. He received his initial funding for AIRS in 1978, and he continued to develop and advocate the concept over the succeeding years. As NASA formulated plans for its multidecadal Earth Observing System (EOS), Mous was intimately involved as a member of NASA’s Earth System Sciences Committee. The proposed AIRS instrument received broad-based support because of its potential applications for both weather forecasting and climate change research. Consequently, it was selected in 1988 to be one of the primary Earth-observing instruments on the Aqua satellite (originally known as EOS PM). Mous was selected as the first AIRS science team leader and remained in that position until his death over 20 years later.