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Proceedings Paper • Open Access

Effects of thermal deformation on optical instruments for space application

Paper Abstract

Optical instruments for space missions work in hostile environment, it’s thus necessary to accurately study the effects of ambient parameters variations on the equipment.

In particular optical instruments are very sensitive to ambient conditions, especially temperature. This variable can cause dilatations and misalignments of the optical elements, and can also lead to rise of dangerous stresses in the optics. Their displacements and the deformations degrade the quality of the sampled images.

In this work a method for studying the effects of the temperature variations on the performance of imaging instrument is presented. The optics and their mountings are modeled and processed by a thermo-mechanical Finite Element Model (FEM) analysis, then the output data, which describe the deformations of the optical element surfaces, are elaborated using an ad hoc MATLAB routine: a non-linear least square optimization algorithm is adopted to determine the surface equations (plane, spherical, nth polynomial) which best fit the data. The obtained mathematical surface representations are then directly imported into ZEMAX for sequential raytracing analysis. The results are the variations of the Spot Diagrams, of the MTF curves and of the Diffraction Ensquared Energy due to simulated thermal loads.

This method has been successfully applied to the Stereo Camera for the BepiColombo mission reproducing expected operative conditions.

The results help to design and compare different optical housing systems for a feasible solution and show that it is preferable to use kinematic constraints on prisms and lenses to minimize the variation of the optical performance of the Stereo Camera.

Paper Details

Date Published: 20 November 2017
PDF: 7 pages
Proc. SPIE 10565, International Conference on Space Optics — ICSO 2010, 1056522 (20 November 2017); doi: 10.1117/12.2309249
Show Author Affiliations
E. Segato, CISAS G. Colombo (Italy)
V. Da Deppo, CNR-IFN Padova (Italy)
S. Debei, Univ. degli Studi di Padova (Italy)
CISAS G. Colombo (Italy)
G. Cremonese, INAF - Osservatorio Astronomico di Padova (Italy)

Published in SPIE Proceedings Vol. 10565:
International Conference on Space Optics — ICSO 2010
Errico Armandillo; Bruno Cugny; Nikos Karafolas, Editor(s)

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