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

Joseph R. Maly; Paul J. Keas; Roger M. Glaese

doi:10.1117/12.432734

2 July 2001 Damping SOFIA: passive and active damping for the Stratospheric Observatory for Infrared Astronomy

Joseph R. Maly, Paul J. Keas, Roger M. Glaese

Proceedings Volume 4331, Smart Structures and Materials 2001: Damping and Isolation; (2001) https://doi.org/10.1117/12.432734
Event: SPIE's 8th Annual International Symposium on Smart Structures and Materials, 2001, Newport Beach, CA, United States

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.

Citation Download Citation

Joseph R. Maly, Paul J. Keas, and Roger M. Glaese "Damping SOFIA: passive and active damping for the Stratospheric Observatory for Infrared Astronomy", Proc. SPIE 4331, Smart Structures and Materials 2001: Damping and Isolation, (2 July 2001); https://doi.org/10.1117/12.432734

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