Nimbus was a research program conducted by NASA in the 1960s and 1970s to study the Earth's atmosphere and weather via satellites in polar orbit. This artifact, an engineering protype of SIRS-A (Satellite Infrared Spectrometer), is representative of a key research instrument, called a sounder, used to measure temperature and water vapor at different levels in the atmosphere.
A SIRS-A sounder flew on Nimbus 3, launched in 1969, and was the first space-based instrument to acquire a temperature profile of the atmosphere. Its first reading occured over Kingston, Jamaica, which, as a test of the sounder's performance, was compared with readings acquired by a balloon radiosonde.
The National Oceanic and Atmospheric Administration transferred this artifact to the Museum in 1987.
Transferred from NOAA