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Lessons Learned During Cryogenic Optical Testing of the Advanced Mirror System Demonstrators (AMSDs)Optical testing in a cryogenic environment presents a host of challenges above and beyond those encountered during room temperature testing. The Advanced Mirror System Demonstrators (AMSDs) are 1.4 m diameter, ultra light-weight (<20 kg/mA2), off-axis parabolic segments. They are required to have 250 nm PV & 50 nm RMS surface figure error or less at 35 K. An optical testing system, consisting of an Instantaneous Phase Interferometer (PI), a diffractive null corrector (DNC), and an Absolute Distance Meter (ADM), was used to measure the surface figure & radius-of-curvature of these mirrors at the operational temperature within the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The Ah4SD program was designed to improve the technology related to the design, fabrication, & testing of such mirrors in support of NASA s James Webb Space Telescope (JWST). This paper will describe the lessons learned during preparation & cryogenic testing of the AMSDs.
Document ID
20040068063
Document Type
Preprint (Draft being sent to journal)
Authors
Hadaway, James (Alabama Univ. Huntsville, AL, United States)
Reardon, Patrick (Alabama Univ. Huntsville, AL, United States)
Geary, Joseph (Alabama Univ. Huntsville, AL, United States)
Robinson, Brian (Alabama Univ. Huntsville, AL, United States)
Stahl, Philip (NASA Marshall Space Flight Center Huntsville, AL, United States)
Eng, Ron (NASA Marshall Space Flight Center Huntsville, AL, United States)
Kegley, Jeff (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Optics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.