posted November 30, 2012
Several internal areas (radiant barrier panels in the inner dome section and the sun shield surfaces) of JWST Chamber A were cleaned using procedures recommended by Aerospace. The recommended procedure for rusted areas was to thoroughly clean the areas and apply a rust inhibitor, followed by primer and paint. Aerospace reviewed and approved the work performed to remediate these areas in the dome where rust was present. Following cleaning of the front surface of the radiant barrier panels in the dome section of Chamber A, NASA Johnson Space Center personnel removed one of the panels, inspected it, and found contamination on the back side.
Aerospace performed a detailed assessment of the air flow dynamics in the chamber, showing that the very low air velocity and laminar flow at low Reynolds number between the chamber shell wall and the radiant barrier would not dislodge the contaminants from the surface. Since the air flow between the wall and the radiant barrier is also not in the direct path of the JWST test article, the risk of contamination of the test article is low. JWST program management concurred with Aerospace’s assessment and agreed with the decision not to remove the panels for cleaning. Aerospace personnel completed the final visual and wipe inspection of the cleaned inner dome surfaces and the sun shield surfaces and penetrations, and gave approval for the next installation tasks. Aerospace also prepared cost estimates for cleaning the large chamber door and the external areas of the chamber that will face into the new cleanroom; refurbishment and outfitting the manlocks on levels 1, 3 and 5, as well as operations and maintenance of the new cleanroom. Aerospace personnel presented a plan for cleanliness certification of the chamber, which was accepted by JWST program management.