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Proceedings Paper

Finite element analysis of the LOLA receiver telescope lens
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Paper Abstract

This paper presents the finite element stress and distortion analysis completed on the receiver telescope lens of the Lunar Orbiter Laser Altimeter (LOLA). LOLA is one of six instruments on the Lunar Reconnaissance Orbiter (LRO), scheduled to launch in 2008. LOLA's main objective is to produce a high-resolution global lunar topographic model to aid in safe landings and enhance surface mobility in future exploration missions. A receiver telescope captures the laser pulses transmitted through a diffractive optical element (DOE) and reflected off the lunar surface. The largest lens of the receiver telescope was modeled with solid elements and constrained in a manner consistent with the behavior of the mounting configuration. Twenty-one temperature load cases were mapped to the nodes based on thermal analysis completed by LOLA's lead thermal analyst, and loads were applied to simulate the preload applied from the ring flexure. The thermal environment of the baseline design produces large radial and axial gradients in the lens. These large gradients create internal stresses that may lead to part failure, as well as significant bending that degrades optical performance. The high stresses and large distortions shown in the analysis precipitated a design change from BK7 glass to sapphire.

Paper Details

Date Published: 23 October 2007
PDF: 11 pages
Proc. SPIE 6675, Optical Modeling and Performance Predictions III, 66750Q (23 October 2007); doi: 10.1117/12.732456
Show Author Affiliations
Elizabeth A. Matzinger, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 6675:
Optical Modeling and Performance Predictions III
Mark A. Kahan, Editor(s)

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