Aboard the Space Shuttle Atlantis, the STS-37 mission launched April 5, 1991 from launch pad 39B at the Kennedy Space Center in Florida, and landed back on Earth April 11, 1991. The 39th shuttle mission included crew members: Steven R. Nagel, commander; Kenneth D. Cameron, pilot; Jerry L,. Ross, mission specialist 1; Jay Apt, mission specialist 2; and Linda M. Godwin, mission specialist 3. The primary payload for the mission was the Gamma Ray Observatory (GRO). The GRO included the Burst and Transient Experiment (BATSE); the Imaging Compton Telescope (COMPTEL); the Energetic Gamma Ray Experiment Telescope (EGRET); and the Oriented Scintillation Spectrometer Experiment (OSSEE). Secondary payloads included Crew and Equipment Translation Aids (CETA); the Ascent Particle Monitor (APM); the Shuttle Amateur Radio Experiment II (SAREXII), the Protein Crystal Growth (PCG); the Bioserve Instrumentation Technology Associates Materials Dispersion Apparatus (BIMDA); Radiation Monitoring Equipment III (RMEIII); and Air Force Maui Optical Site (AMOS).