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Pre- and Post-Launch Performance of the NICMOS Dewar

  • C. D. Miller
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 43)

Abstract

Approximately 14 months prior to launch, the NICMOS solid nitrogen dewar was filled with its flight load of cryogen and successfully completed subsystem verification testing. The dewar remained filled with solid nitrogen throughout instrument integration and testing, with periodic recooling of the cryogen to avoid venting. Thermal expansion and possible migration of the solid nitrogen during the recool-warmup cycles resulted in an unexpected shift in detector focus positions, revealed during an instrument-level optical system test. The results of an investigation of this anomaly are discussed. The instrument successfully completed system calibration and verification testing, and the cryogen sublimation rate measured during calibration was within 10% of the thermal model estimate. Subsequent recool-warmup cycles indicated that the expansion had stabilized at an acceptable level. However, shortly after launch and installation into HST, the solid nitrogen expanded further than before, moving one of the three detectors out of focus adjustment range. This expansion also caused physical contact of optical baffle segments, and a resulting large increase in the cryogen heat load and sublimation rate. Recent trends in the detector motion and heat load are discussed.

Keywords

Hubble Space Telescope Focus Position Thermoelectric Cooler Sublimation Rate Focus Measurement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    C. D. Miller, Development of the long-lifetime solid nitrogen dewar for NICMOS, to be presented at the 1997 Cryogenic Engineering Conference, July 28 to August 1, 1997, Portland, OR.Google Scholar
  2. 2.
    R. E. Dame and E. Cofie, A final report on the thermal expansion analysis of the NICMOS cryogenic subsystem’s dewar, prepared under Sub-Contract SC00891 for Fairchild Space Contract NAS5–32539, December 18, 1996.Google Scholar
  3. 3.
    R. E. Dame, Results of low cycle sample fatigue tests conducted on 5083–0 billet material used for the NICMOS dewar nitrogen tank, Mega Engineering Report, December 4, 1996.Google Scholar
  4. 4.
    R. L. Pederson, C. D. Miller, M. P. Schulze, and K. Blount, Mechanical properties of solid nitrogen between 40 K and 58 K, to be presented at the 1997 International Cryogenic Materials Conference, July 28 to August 1, 1997, Portland, OR.Google Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • C. D. Miller
    • 1
  1. 1.Ball Aerospace Systems DivisionBoulderUSA

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