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Proceedings Paper

Damping SOFIA: passive and active damping for the Stratospheric Observatory for Infrared Astronomy
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Paper Abstract

The Stratospheric Observatory For Infrared Astronomy, SOFIA is being developed by NASA and the German space agency, Deutschen Zentrum fur Luft- und Raumfahrt (DLR), with an international contractor team. The 2.5-meter reflecting telescope of SOFIA will be the world's largest airborne telescope. Flying in an open cavity on a modified 747 aircraft, SOFIA will perform infrared astronomy while cruising at 41,000 feet and while being buffeted by a 550- mile-per-hour slipstream. A primary system requirement of SOFIA is tracking stability of 0.2 arc-seconds, and a 3-axis pointing control model has been used to evaluate the feasibility of achieving this kind of stability. The pointing control model shows that increased levels of damping in certain elastic modes of the telescope assembly will help achieve the tracking stability goal and also expand the bandwidth of the attitude controller. This paper describes the preliminary work that has been done to approximate the reduction in image motion yielded by various structure configurations that use reaction masses to attenuate the flexible motions of the telescope structure. Three approaches are considered: passive tuned-mass dampers, active-mass dampers, and attitude control with reaction-mass actuators. Expected performance improvements for each approach, and practical advantages and disadvantages associated with each are presented.

Paper Details

Date Published: 2 July 2001
PDF: 12 pages
Proc. SPIE 4331, Smart Structures and Materials 2001: Damping and Isolation, (2 July 2001); doi: 10.1117/12.432734
Show Author Affiliations
Joseph R. Maly, CSA Engineering, Inc. (United States)
Paul J. Keas, Orbital Sciences Corp. and NASA Ames Research Ctr. (United States)
Roger M. Glaese, CSA Engineering, Inc. (United States)

Published in SPIE Proceedings Vol. 4331:
Smart Structures and Materials 2001: Damping and Isolation
Daniel J. Inman, Editor(s)

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