Correcting the Antenna Temperature of an Earth-Observing Microwave Instrument for Extraterrestrial Contamination

Microwave antennas deployed for spaceborne radiometers are diffraction-limited, with typical beam efficiency of about 90%, and provide relatively poor selectivity against radiation from celestial bodies (Moon, Sun, galaxy) when they are at the side or back of the instrument. Traditionally, this contamination has been removed by preparing multiple data files that represent the relative position of the spacecraft and the celestial sources throughout the mission lifetime.