Spacecraft Contamination under Simulated Orbital Environment.
Abstract
Volatile condensable material (VCM) measurements on a number of spacecraft materials have indicated that contamination rates onto surfaces at subambient temperatures cannot be predicted from standard outgassing tests, particularly where long-term exposures are involved. Contamination rates may depend markedly on temperature differentials between source and collector, the collection temperature, the source geometry and the exposure time. Contamination rates may also be influenced by solar irradiation. The results of this study were obtained on a new VCM facility that overcomes many deficiencies experienced in earlier designs and permits accurate simulation of space environmental conditions. Advantages of the present system include an oil-free, high-vacuum chamber (1 to 10 nanotorr) source temperatures from ambient to 125 C, collection temperatures from -140 to +125 C, total mass-loss measurements, in-situ VCM mass measurements with use of an internal-temperature-compensated quartz-crystal microbalance, in-situ vacuum ultraviolet irradiation of either the specimen or of the collected VCM, and infrared identification of the VCM by multiple internal reflection spectroscopy. The system also features automated data acquisition and data processing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 06, 1977
- Accession Number
- ADA042433
Entities
People
- Lucio U. Tolentino
- Roger W. Phillips
- Seymour Feuerstein
Organizations
- The Aerospace Corporation