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Record 45 of 8684
Silicone Contamination Camera for Developed for Shuttle Payloads
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Abstract: On many shuttle missions, silicone contamination from unknown sources from within or external to the shuttle payload bay has been a chronic problem plaguing experiment payloads. There is currently a wide range of silicone usage on the shuttle. Silicones are used to coat the shuttle tiles to enhance their ability to shed rain, and over 100 kg of RTV 560 silicone is used to seal white tiles to the shuttle surfaces. Silicones are also used in electronic components, potting compounds, and thermal control blankets. Efforts to date to identify and eliminate the sources of silicone contamination have not been highly successful and have created much controversy. To identify the sources of silicone contamination on the space shuttle, the NASA Lewis Research Center developed a contamination camera. This specially designed pinhole camera utilizes low-Earth-orbit atomic oxygen to develop a picture that identifies sources of silicone contamination on shuttle-launched payloads. The volatile silicone species travel through the aperture of the pinhole camera, and since volatile silicone species lose their hydrocarbon functionalities under atomic oxygen attack, the silicone adheres to the substrate as SiO_x. This glassy deposit should be spatially arranged in the image of the sources of silicone contamination. To view the contamination image, one can use ultrasensitive thickness measurement techniques, such as scanning variable-angle ellipsometry, to map the surface topography of the camera's substrate. The demonstration of a functional contamination camera would resolve the controversial debate concerning the amount and location of contamination sources, would allow corrective actions to be taken, and would demonstrate a useful tool for contamination documentation on future shuttle payloads, with near negligible effect on cost and weight.
Publication Date: Mar 01, 1996
Document ID:
20050177187
(Acquired Jun 16, 2005)
Subject Category: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
Document Type: Technical Report
Publication Information: Research and Technology 1995; (NASA-TM-107111)
Financial Sponsor: NASA Lewis Research Center; Cleveland, OH, United States
Organization Source: NASA Lewis Research Center; Cleveland, OH, United States
Description: 2p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: SILICONES; CONTAMINATION; CAMERAS; SPACE SHUTTLE PAYLOADS; THICKNESS; SPACE SHUTTLE MISSIONS; TEMPERATURE CONTROL; SPACECRAFT LAUNCHING; TILES; GLASS; HYDROCARBONS
Miscellaneous Notes: See Document ID 19960041413
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