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Proceedings Paper

Optical chopper for the HIRDLS instrument
Author(s): Walter G Opyd; Stuart Loewenthal
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Paper Abstract

Requirements, performance and life-test results are presented for the optical chopper installed in the High-Resolution Dynamics Limb Sounder (HIRDLS) to be flown on the AURA mission of the NASA Earth Observing System (EOS). Optical chopping is essential in order to achieve the required sensitivity and accuracy in measurement of infrared emission from various chemical species in the earth's atmosphere. Chopping of the optical input as far forward in the telescope as practical minimizes calibration errors arising from variations in emission from warm optics and due to electronic drifts in the infrared detecting system. At 500 Hz, a reflective chopper blade is used to alternate the instrument view between the atmospheric limb and cold space. The HIRDLS chopper is a six-toothed, mirrored wheel driven by a brushless DC motor. Chopper design was driven by requirements of 1) continuous operation at 5000 RPM for 50,000 hours in space vacuum, 2) chopping amplitude stability of one part in 100,000, 3) lubricant loss control for both bearing reliability and prevention of optics contamination, 4) compact size to fit in the folded telescope, and 5) survival in the launch environment.

Paper Details

Date Published: 10 November 2003
PDF: 12 pages
Proc. SPIE 5152, Infrared Spaceborne Remote Sensing XI, (10 November 2003); doi: 10.1117/12.510435
Show Author Affiliations
Walter G Opyd, Lockheed Martin Advanced Technology Ctr. (United States)
Stuart Loewenthal, Lockheed Martin Space Systems Co. (United States)

Published in SPIE Proceedings Vol. 5152:
Infrared Spaceborne Remote Sensing XI
Marija Strojnik, Editor(s)

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