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Proceedings Paper

Results of edge scatter testing for a starshade mission
Author(s): Suzanne Casement; Steve Warwick; Daniel Smith; Scott Ellis; John Stover
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Paper Abstract

In the field of exoplanet detection and characterization, the use of a starshade, an external occulter in front of a telescope at large separations, has been identified as one of the highly promising methods to achieve the necessary high contrast imagery. Control of scattered sunlight from the edges of the starshade into the telescope has been identified as one of the key technology development areas in order to make the starshade feasible. Modeling of the scattered light has resulted in very different results so a campaign of experimentation with edge samples was undertaken to attempt to understand the discrepancies. Here, we present our results from the measurement of select samples of materials which would be suitable for manufacturing the starshade edge, and related models. We have focused on coating metallic samples for ease of fabrication: Titanium, Aluminum, and a Beryllium Copper alloy. Using standard machine shop methods, we fabricated samples which had sharp edges with radius of curvature (RoC) between 15 and 20 μm. We then had these samples coated by two suppliers to evaluate how well these coating types would conform to the edge and provide scatter suppression. The results of scatter measurements of these coated edge samples are presented. These scatter results have been incorporated into a new geometrical model in FRED which includes the details of the starshade mechanical model. This model predicts both the magnitude and distribution of the scattered sunlight in the image plane of a nominal telescope. We present these results, including a first effort at modeling the Solar System at 10 pc as seen by this mission architecture.

Paper Details

Date Published: 29 July 2016
PDF: 11 pages
Proc. SPIE 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, 99043H (29 July 2016); doi: 10.1117/12.2231808
Show Author Affiliations
Suzanne Casement, Northrop Grumman Aerospace Systems (United States)
Steve Warwick, Northrop Grumman Aerospace Systems (United States)
Daniel Smith, Northrop Grumman Aerospace Systems (United States)
Scott Ellis, Photon Engineering LLC (United States)
John Stover, The Scatter Works Inc. (United States)

Published in SPIE Proceedings Vol. 9904:
Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave
Howard A. MacEwen; Giovanni G. Fazio; Makenzie Lystrup; Natalie Batalha; Nicholas Siegler; Edward C. Tong, Editor(s)

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