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Proceedings Paper

Microprecision interferometer: pointing system performance in on-orbit disturbance environment
Author(s): Frank G. Dekens; Gregory W. Neat
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Paper Abstract

We investigate how the Space Interferometer Mission (SIM) will be able to meet its instrument astrometric pointing requirements. The most demanding SIM pointing requirement is to independently point each interferometer arm to better than 0.07 micro-radian RMS residual jitter using a 0.01 Hz bandwidth optical sensor. The predominant contributors to the pointing error are the spinning spacecraft reaction wheel assemblies which emit disturbances from 2 Hz to 1 kHz. An estimate of the residual pointing error is presented for this most challenging vibration attenuation problem which is with isolated reaction wheels with no optical compensation. Central to this estimate is the Micro-Precision Interferometer testbed which is a softly suspended hardware model of a future space-borne optical interferometer and is dimensionally representative of SIM. The prediction of the on-orbit pointing error is determined in part by measuring broadband disturbance transfer functions from the testbed's isolated reaction wheel location to the camera output, where the pointing must be stabilized. Off-line, the procedure combines the measured testbed transfer functions with an empirical model of the reaction wheel disturbance to determine jitter over the entire range of wheel speeds. Results suggest that the most demanding SIM pointing requirement is currently violated by a factor of ten.

Paper Details

Date Published: 9 June 1999
PDF: 14 pages
Proc. SPIE 3668, Smart Structures and Materials 1999: Smart Structures and Integrated Systems, (9 June 1999); doi: 10.1117/12.350691
Show Author Affiliations
Frank G. Dekens, Jet Propulsion Lab. (United States)
Gregory W. Neat, Jet Propulsion Lab. (United States)


Published in SPIE Proceedings Vol. 3668:
Smart Structures and Materials 1999: Smart Structures and Integrated Systems
Norman M. Wereley, Editor(s)

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