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Proceedings Paper • Open Access

Development of the Laser Retroreflector Array (LRA) for SARAL
Author(s): Vincent Costes; Karine Gasc; Pierre Sengenes; Corinne Salcedo; Stéphan Imperiali; Christian du Jeu

Paper Abstract

CNES (French spatial agency) will provide the AltiKa high resolution altimeter, Doris instrument and the LRA (Laser Retroreflector Array) for SARAL (Satellite with Argos and AltiKa) in cooperation with ISRO (Indian space agency).

The LRA is a passive equipment reflecting the laser beams coming from the Earth ground stations. Computing the send-return time travel of the laser beams allows the determination of the satellite altitude within an accuracy of a few millimeters. The reflective function is done by a set of 9 corner cube reflectors, with a conical arrangement providing a 150 degrees wide field of view over the full 360 degrees azimuth angle.

According to CNES optomechanical specifications, the LRA has been developed by SESO (French optical firm). SESO has succeeded in providing the corner cube reflectors with a very stringent dihedral angle error of 1.6 arcsec and an accuracy within ±0.5 arcsec. During this development, SESO has performed mechanical, thermal and thermo-optical analyses. The optical gradient of each corner cube, as well as angular deviations and PSF (Point Spread Function) in each laser range finding direction, have been computed. Mechanical and thermal tests have been successfully performed. A thermo-optical test has successfully confirmed the optical effect of the predicted in-flight thermal gradients.
Each reflector is characterized in order to find its best location in the LRA housing and give the maximum optimization to the space telemetering mission.

Paper Details

Date Published: 20 November 2017
PDF: 4 pages
Proc. SPIE 10565, International Conference on Space Optics — ICSO 2010, 105652K (20 November 2017); doi: 10.1117/12.2309261
Show Author Affiliations
Vincent Costes, Ctr. National d'Études Spatiales (France)
Karine Gasc, Ctr. National d'Études Spatiales (France)
Pierre Sengenes, Ctr. National d'Etudes Spatiale (France)
Corinne Salcedo, Ctr. National d'Études Spatiales (France)
Stéphan Imperiali, Thales SESO (France)
Christian du Jeu, Thales SESO (France)

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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