MIDCOURSE SPACE EXPERIMENT CONTAMINATION MEASUREMENT DURING CRYOGEN PHASE

In-orbit measurements with contamination-monitoring instruments were u sed 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 10 months showed water vapor as the largest gaseous species, with argon gas from a venting source important only during the first week in orbi t. Simple reporting tools were used for rapid assessments of the space craft environment during early operations. The contamination levels an d the decay rate of water vapor around the spacecraft were found to be in excellent agreement with prelaunch predictions. Future measurement s include validation of the model of the aging spacecraft and investig ation of the degradation of thermal radiators.