The 13th flight of the Space Shuttle (STS 41-G) carried the OSTA-3 (Office of Space and Terrestrial Applications) payload designed for conducting experiments in earth remote sensing. This experiment ... payload consisted of 1) a Shuttle Imaging Radar (SIR-B) for studies of the earth's surface, 2) a Large Format Camera (LFC) for cartographic mappings of the earth, 3) a Measurement of Air Pollution from Satellite (MAPS) experiment to determine the distribution of CO in the atmosphere, and 4) a Feature Identification and Location Experiment (FILE) for classification of surface materials. The SIR-B was an upgraded version of the SIR-A flown on the OSTA-1 payload during the STS-2 mission (NSSDC ID 81-111A-01). The MAPS and FILE sensors were the reflies of those same instruments on the OSTA-1 payload (NSSDC ID 81-111A-04 and 81-111A-03). The mission lasted 8 days and, except for SIR-B, all instruments met their pre launch requirements.