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Proceedings Paper

WFIRST Phase B HLC occulter mask baselining and testbed WFC performance validation
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Paper Abstract

Occulter mask fabrication for Hybrid Lyot Coronagraph (HLC) at JPL is a relatively mature technology as past successful testbed demonstrations can attest. Nevertheless, as NASA’s WFIRST mission moved into Phase B, new mask design space and fabrication process were explored for new requirements and for better performances for the CoronaGraph Instrument (CGI). To minimize the risks associated with the new explorations, CGI modeling team is tasked with assessing the viability of new designs. In this paper, we describe our HLC modeling effort and results, which identified the potential risks with early exploratory designs and modified fabrication processes. As a result, the traditional (proven) style design is kept for risk aversion. Along the way a standard procedure has been developed for systematic mask evaluation, mask baselining, and general flight performance prediction. In the second part, we describe our model validation effort for the chosen baseline mask’s testbed performance. The focus of the testbed demonstration is to address a major concern related to the CGI’s limited time for wavefront control (WFC) in flight. It includes two stages of WFC: ground seed generation WFC, and (simulated) in-orbit commissioning phase WFC. Good agreements have been achieved in both stages of WFC which affirms that the CGI is capable of digging a dark hole that meets raw contrast requirement within the required time allocation. It also represents a significant improvement in our HLC WFC modeling for an as-built real system.

Paper Details

Date Published: 9 September 2019
PDF: 9 pages
Proc. SPIE 11117, Techniques and Instrumentation for Detection of Exoplanets IX, 111170H (9 September 2019); doi: 10.1117/12.2530672
Show Author Affiliations
Hanying Zhou, Jet Propulsion Lab. (United States)
John E. Krist, Jet Propulsion Lab. (United States)
Brian D. Kern, Jet Propulsion Lab. (United States)
Byoung-Joon Seo, Jet Propulsion Lab. (United States)
Eric Cady, Jet Propulsion Lab. (United States)
Bijan Nemati, The Univ. of Alabama in Huntsville (United States)
Dwight Moody, Jet Propulsion Lab. (United States)
A.J. Eldorado Riggs, Jet Propulsion Lab. (United States)
David S. Marx, Jet Propulsion Lab. (United States)
Daniel Wilson, Jet Propulsion Lab. (United States)
Kunjithapatham Balasubramanian, Jet Propulsion Lab. (United States)
Ilya Y. Poberezhskiy, Jet Propulsion Lab. (United States)
Scott A. Basinger, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 11117:
Techniques and Instrumentation for Detection of Exoplanets IX
Stuart B. Shaklan, Editor(s)

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