Temperature induced distortions in space telescope mirrorsIn this paper, it is illustrated how measured instantaneous coefficients of thermal expansion (CTE) can be accurately taken into account when modeling the structural behavior of space based optical systems. In particular, the importance of including CTE spatial variations in the analysis of optical elements is emphasized. A comparison is made between the CTE's of three optical materials commonly used in the construction of space mirrors (ULE, Zerodur, and beryllium). The overall impact that selection of any one of these materials has on thermal distortions is briefly discussed. As an example of how temperature dependent spatial variations in thermal strain can be accurately incorporated in the thermo-structural analysis of a precision optical system, a finite element model is developed, which is used to estimate the thermally induced distortions in the Hubble Space Telescope's (HST) primary mirror. In addition to the structural analysis, the optical aberrations due to thermally induced distortions are also examined. These calculations indicate that thermal distortions in HST's primary mirror contribute mainly to defocus error with a relatively small contribution to spherical aberration.
Document ID
19930036205
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Nied, H. F. (General Electric Co. Schenectady, NY, United States)
Rudmann, A. A. (NASA Space Station Freedom Program Office Reston, VA, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1993
Subject Category
Optics
Report/Patent Number
AIAA PAPER 93-0097
Meeting Information
Meeting: AIAA, Aerospace Sciences Meeting and Exhibit