Midcourse Space Experiment Contamination Measurement During Cryogen Phase

In-orbit measurements with contamination-monitoring instruments were used to validate the Midcourse Space Experiment contamination model and to investigate the phenomenon of molecular and particle generation in space. Measurements from the first orbit contact through the first ten months showed water vapor as the largest gaseous species, with argon gas from a venting source important only during the first week in orbit. Simple reporting tools were used for rapid assessments of the spacecraft environment during early operations. The contamination levels and the decay rate of water vapor around the spacecraft were found to be in excellent agreement with prelaunch predictions. Future measurements include validation of the model of the aging spacecraft and investigation of the degradation of thermal radiators. (Author)