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WFIRST Low Order Wavefront Sensing and Control Testbed Performance under Flight Like Photon Flux

Show simple item record Shi, Fang Seo, Byoung-Joon Cady, Eric Kern, Brian Lam, Raymond Marx, David Patterson, Keith Prada, Camilo Mejia Shaw, John Shelton, Chris Shields, Joel Tang, Hong Truong, Tuan 2020-05-14T22:55:43Z 2020-05-14T22:55:43Z 2018-06-12
dc.identifier.citation SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, June 12 - 14, 2018 en_US
dc.identifier.clearanceno 18-3341
dc.description.abstract To maintain the required performance for the WFIRST Coronagraph Instrument (CGI) in a realistic space environment, a Low Order Wavefront Sensing and Control (LOWFS/C) subsystem is necessary. The WFIRST CGI LOWFS/C subsystem would use the Zernike wavefront sensor, which has the phase-shifting disk combined with the coronagraph’s focal plane mask, to sense the low-order wavefront drift and line-of-sight (LoS) error using the rejected starlight. The dynamic tests on JPL’s on the Occulting Mask Coronagraph (OMC) Testbed have demonstrated that LOWFS/C can maintain coronagraph contrast to better than 10-8 in presence of WFIRST-like line of sight and low order wavefront disturbances in both Shaped Pupil Coronagraph (SPC) and Hybrid Lyot Coronagraph (HLC) modes. However, the previous dynamic tests have been done using a bright source with photon flux equivalent to stellar magnitude of Mv = -3.5. The LOWFS/C technology development continues on the OMC testbed especially in evaluating and improving the LOWFS/C performance under the realistic photon flux that is equivalent to WFIRST Coronagraph target stars. Our recent testbed tests have demonstrated that the LOWFS/C can work cohesively with the stellar light suppression wavefront control, which brings broad band coronagraph contrast from 1x10-6 to 6x10-9, while LOWF/C is simultaneously suppressing the WFIRST like LoS and low order wavefront drift disturbances on a source that photon flux is equivalent to a Mv = 2 star. This demonstration mimics the CGI initial dark hole establish process on a bright reference star. We also demonstrated on the testbed that LOWFS/C can maintain the coronagraph contrast by suppressing the WFIRST like line-of-sight disturbances on a fainter Mv = 5 star. This mimics scenario of CGI science target observations. In this paper we will present the recent testbed results on LOWFS/C LoS loops and low order wavefront error correction loop performance on the flight like photon flux. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher Pasadena, CA: Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2018 en_US
dc.subject WFIRST Coronagraph en_US
dc.subject Exoplanet en_US
dc.subject wavefront sensing and control en_US
dc.subject low order wavefront sensor en_US
dc.subject high contrast imaging en_US
dc.subject Zernike wavefront sensor en_US
dc.subject fast steering mirror en_US
dc.subject deformable mirror en_US
dc.title WFIRST Low Order Wavefront Sensing and Control Testbed Performance under Flight Like Photon Flux en_US
dc.type Preprint en_US

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