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Proceedings Paper

Passive isolator design for jitter reduction in the Terrestrial Planet Finder Coronagraph
Author(s): Carl Blaurock; Kuo-Chia Liu; Larry Dewell; James Alexander
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Paper Abstract

Terrestrial Planet Finder (TPF) is a mission to locate and study extrasolar Earthlike planets. The TPF Coronagraph (TPF-C), planned for launch in the latter half of the next decade, will use a coronagraphic mask and other optics to suppress the light of the nearby star in order to collect visible light from such planets. The required contrast ratio of 5e-11 can only be achieved by maintaining pointing accuracy to 4 milli-arcseconds, and limiting optics jitter to below 5 nm. Numerous mechanical disturbances act to induce jitter. This paper concentrates on passive isolation techniques to minimize the optical degradation introduced by disturbance sources. A passive isolation system, using compliant mounts placed at an energy bottleneck to reduce energy transmission above a certain frequency, is a low risk, flight proven design approach. However, the attenuation is limited, compared to an active system, so the feasibility of the design must be demonstrated by analysis. The paper presents the jitter analysis for the baseline TPF design, using a passive isolation system. The analysis model representing the dynamics of the spacecraft and telescope is described, with emphasis on passive isolator modeling. Pointing and deformation metrics, consistent with the TPF-C error budget, are derived. Jitter prediction methodology and results are presented. Then an analysis of the critical design parameters that drive the TPFC jitter response is performed.

Paper Details

Date Published: 18 August 2005
PDF: 12 pages
Proc. SPIE 5867, Optical Modeling and Performance Predictions II, 58670Y (18 August 2005); doi: 10.1117/12.619328
Show Author Affiliations
Carl Blaurock, Nightsky Systems, Inc. (United States)
Kuo-Chia Liu, NASA Goddard Space Flight Ctr. (United States)
Larry Dewell, Lockheed Martin Space Systems (United States)
James Alexander, NASA Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 5867:
Optical Modeling and Performance Predictions II
Mark A. Kahan, Editor(s)

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