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Proceedings Paper

ACIS door failure investigation: technical details and mitigation procedures
Author(s): Mark A. Kahan; Neil L. Tice; William A. Podgorski; Paul P. Plucinsky; Keith B. Doyle
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Paper Abstract

NASA's Chandra X-ray Observatory (formerly AXAF) was launched on July 23, 1999 and is currently in orbit performing scientific studies. Chandra is the third of NASA's Great Observatories to be launched, following the Hubble Space Telescope and the Compton Gamma Ray Observatory. One of four primary science instruments on Chandra, and one of only two focal plane instruments, is the Advanced CCD Imaging Spectrometer, or ACIS. The ACIS focal plane and Optical Blocking Filter needed to be launched under vacuum, so a tightly sealed, functioning door and venting subsystem were implemented. The door was opened two and one-half weeks after launch (after most out-gassing of composite materials) and allowed X-rays to be imaged by the ACIS CCD's in the focal plane. A failure of this door to open on-orbit would have eliminated all ACIS capabilities, severely degrading mirror science. During the final pre- flight thermal-vacuum test of the fully integrated Chandra Observatory at TRW, the ACIS door failed to open when commanded to do so. This paper provides a somewhat technically expanded description of the efforts, under considerable time pressure, by NASA, its contractors and outside review teams to investigate the failure and to develop modified hardware and procedures which would correct the problem.

Paper Details

Date Published: 6 March 2001
PDF: 20 pages
Proc. SPIE 4198, Optomechanical Engineering 2000, (6 March 2001); doi: 10.1117/12.417341
Show Author Affiliations
Mark A. Kahan, Optical Research Associates (United States)
Neil L. Tice, Lockheed Martin Missiles & Space (United States)
William A. Podgorski, Smithsonian Astrophysical Observatory (United States)
Paul P. Plucinsky, Smithsonian Astrophysical Observatory (United States)
Keith B. Doyle, Optical Research Associates (United States)

Published in SPIE Proceedings Vol. 4198:
Optomechanical Engineering 2000
Mark A. Kahan, Editor(s)

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