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Proceedings Paper

Starshade optical edge modeling, requirements, and laboratory tests
Author(s): Stefan R. Martin; Stuart Shaklan; Samuel Crawford; Siu-Chun Lee; Behrouz Khayatian; Daniel Hoppe; Eric Cady; P. Douglas Lisman
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Paper Abstract

In conjunction with a space telescope of modest size, a starshade can be used as an external occulter to block light from a target star, enabling the detection of exoplanets in close orbits. Typically, the starshade will be placed some 50,000 km from the telescope and the system oriented so that the sun is on the opposite side of the shade to the telescope, but somewhat away from the line of sight. A small amount of sunlight can scatter from the edges of the shade directly into the telescope. Since the photon rate from an earthlike exoplanet might be only a few photons per minute, it is desirable that the scattered sunlight is also near this level. We have built an analytical model of the performance of starshade edges for both specular and Lambertian surfaces and derived requirements for properties such as reflectivity and radius of curvature. A computer model was also developed to show the appearance of the sunlight from the starshade and assess the contrast with the exoplanet. A commercial electromagnetism code was also used to investigate aspects of the results. We also constructed a scatterometer with which various test edges were measured and derived the likely performance if used in a starshade. We discuss these models and give the principal results.

Paper Details

Date Published: 26 September 2013
PDF: 10 pages
Proc. SPIE 8864, Techniques and Instrumentation for Detection of Exoplanets VI, 88641A (26 September 2013); doi: 10.1117/12.2024188
Show Author Affiliations
Stefan R. Martin, Jet Propulsion Lab. (United States)
Stuart Shaklan, Jet Propulsion Lab. (United States)
Samuel Crawford, Jet Propulsion Lab. (United States)
Siu-Chun Lee, Applied Sciences Lab., Inc. (United States)
Behrouz Khayatian, Jet Propulsion Lab. (United States)
Daniel Hoppe, Jet Propulsion Lab. (United States)
Eric Cady, Jet Propulsion Lab. (United States)
P. Douglas Lisman, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 8864:
Techniques and Instrumentation for Detection of Exoplanets VI
Stuart Shaklan, Editor(s)

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