This is a flight spare of the Microwave Sounding Unit (MSU), an instrument flown on Tiros meteorological satellites beginning with Tiros-N in 1978. This MSU (designated Flight Model 8) was built in 1984 by the Jet Propulsion Laboratory, but never flew.
The MSU's purpose was to measure the temperature profile of the Earth's atmosphere from the planet's surface to a height of 20 km (12.4 miles). The MSU and other instruments on the Tiros series of satellites data are part of on-going program to gather a range of data on the characteristics of and changes to the Earth's atmosphere over a period of years. MSU data on atmospheric temperatures has contributed to scientific discussions of whether the Earth is experiencing a warming trend.
The last MSU flown in space, launched on the NOAA-14 satellite (part of the Tiros program), in 1994, is still gathering data as of 2007.
The National Oceanic and Atmospheric Administration transferred this artifact to the Museum in 2004.
Transferred from National Oceanic & Atmospheric Administration