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Proceedings Paper

Dim star fringe stabilization demonstration using pathlength feed-forward on the SIM testbed 3 (STB3)
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Paper Abstract

Future space-based optical interferometers such as the Space Interferometer Mission require fringe stabilization to the level of nanometers in order to produce astrometric data at the micro-arc-second level. Even the best attitude control system available to date will not be able to stabilize the attitude of a several thousand pound spacecraft to a few milli-arc-seconds. Active pathlength control is usually implemented to compensate for attitude drift of the spacecraft. This issue has been addressed in previous experiments while tracking bright stars. In the case of dim stars, as the sensor bandwidth falls below one hertz, feedback control will not provide sufficient rejection. However, stabilization of the fringes from a dim-star down to the nanometer level can be done open loop using information from additional interferometers looking at bright guide stars. The STB3 testbed developed at the Jet Propulsion Laboratory features three optical interferometers sharing a common baseline, dynamically representative to the SIM interferometer. An artificial star feeding the interferometers is installed on a separate optics bench. Voice coils are used to simulate the attitude motion of the spacecraft by moving the entire bench. Data measured on STB3 show that fringe motion of a dim star due to spacecraft attitude changes can be attenuated by 80 dB at 0.1Hz without feedback control, using only information from two guide stars. This paper describes the STB3 setup, the pathlength feed-forward architecture, implementation issues and data collected with the system.

Paper Details

Date Published: 26 February 2003
PDF: 12 pages
Proc. SPIE 4852, Interferometry in Space, (26 February 2003); doi: 10.1117/12.460714
Show Author Affiliations
Renaud Goullioud, Jet Propulsion Lab. (United States)
Oscar S. Alvarez-Salazar, Jet Propulsion Lab. (United States)
Bijan Nemati, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 4852:
Interferometry in Space
Michael Shao, Editor(s)

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