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Proceedings Paper

Pointing Performance Analysis Of A Prototype Secondary Mirror Assembly For The Space Infrared Telescope Facility
Author(s): Sarma N. Gullapalli; Mark T. Stier; Michael A. Duffy; Richard A. Rockwell; Francis R. Sileo; Michael H. Krim
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Paper Abstract

The Space Infrared Telescope Facility (SIRTF), a NASA "Great Observatory" to be launched in the late 1990s, is a superfluid helium-cooled one meter class IR telescope with a sophisticated chopping facility provided by a dynamic two-axis tilt control capability of the secondary mirror. This paper describes the pointing performance analysis of the Prototype Secondary Mirror Assembly (PSMA) design. The two-axis PSMA tilt control system employs four linear actuators and four pairs of position eddy current sensors, and a reaction mass system to isolate the servo loops from the structural modes. The actuators and sensors operate in the 4 K environment of the secondary mirror assembly, while the control electronics reside in the "warm" electronics box outside the dewar. The PSMA design meets stringent pointing performance requirements over a range of discrete chop amplitudes and frequencies, for three different dynamic chop modes. The analysis of the pointing performance utilizes a detailed dynamic model of the PSMA in time and frequency domains, including the discretization and quantization effects in the servo-controllers, the sensor noise, and the structural modes. The servo stability issues are also addressed.

Paper Details

Date Published: 26 September 1989
PDF: 14 pages
Proc. SPIE 1111, Acquisition, Tracking, and Pointing III, (26 September 1989); doi: 10.1117/12.977969
Show Author Affiliations
Sarma N. Gullapalli, Perkin-Elmer Corporation (United States)
Mark T. Stier, Perkin-Elmer Corporation (United States)
Michael A. Duffy, Perkin-Elmer Corporation (United States)
Richard A. Rockwell, Perkin-Elmer Corporation (United States)
Francis R. Sileo, Perkin-Elmer Corporation (United States)
Michael H. Krim, Perkin-Elmer Corporation (United States)

Published in SPIE Proceedings Vol. 1111:
Acquisition, Tracking, and Pointing III
Sankaran Gowrinathan, Editor(s)

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