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1 January 1987 Hubble Space Telescope Contamination Analysis
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This paper summarizes the results of several contamination analyses performed in support of Hubble Space Telescope (HST) system development. The discussion topics encompass several flight-phase operational and contamination events: prelaunch standby, on-orbit closed-door and open-door operations, HST interior outgassing, and ram-induced pressure rise in the Aft Shroud (AS) region. A number of refined analytical models (computer codes) have been used to carry out these analyses. The results indicate that the contaminant build-up during prelaunch and flight operations will be well within the HST contaminant allowable limits (about 50% the budget allocation). Specific findings are as follows: (a) no significant contamination of HST primary mirror (PM) and secondary mirror (SM) due to orbiter purge air will occur during prelaunch standby even with a worst-case scenario; (b) using a diffusion flux model and from available data on payload bay (PLB) sources, the deposition rates on the HST PM and SM have been predicted to be 0.4 angstrom/hr and 2.7 angstroms/hr, respectively, during on-orbit closed-door operations; (c) particulate contamination based on a scenario involving two astronauts during extravehicular activity (EVA) in conjunction with instrument change-out has been found to be negligibly small; (d) certain lubricating oils, if deposited on and not removed from HST interior surfaces, could cause significant contamination on HST critical optics; however, this potential contamination has been eliminated by HST thermal hakeout; (e) by utilizing a Monte Carlo model, the ram-induced pressure rise in the AS region has been predicted to be insignificant and would not violate the electric breakdown requirements.
© (1987) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael C. Fong, Milford A. Peterson, and Aleck L. Lee "Hubble Space Telescope Contamination Analysis", Proc. SPIE 0777, Optical Systems Contamination: Effects, Measurement, Control, (1 January 1987);

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