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Proceedings Paper

Ground to on-orbit alignment study of the WFIRST wide-field channel and resulting changes in the telescope architecture
Author(s): John Hagopian; Nerses Armani; Lisa Bartusek; Tom Casey; Dave Content; Yves Conturie; Guangjun Gao; Alden Jurling; Cathy Marx; Joe Marzouk; Bert Pasquale; J. Scott Smith; Hong Tang; Arthur Whipple
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Paper Abstract

The Wide-Field Infrared Survey Telescope (WFIRST) mission[1] is the top-ranked large space mission in the New Worlds, New Horizon (NWNH) Decadal Survey of Astronomy and Astrophysics. WFIRST will settle essential questions in both exoplanet and dark energy research and will advance topics ranging from galaxy evolution to the study of objects within the galaxy. The WFIRST mission uses a repurposed 2.4-m Forward Optical Telescope assembly (FOA), which, when completed with new aft optics will be an Integrated Optical Assembly (IOA). WFIRST is equipped with a Wide Field Instrument (WFI) and a Coronagraph Instrument (CGI). An Instrument Carrier (IC) meters these payload elements together and to the spacecraft bus (S/C). A distributed ground system receives the data, uploads commands and software updates, and processes the data. After transition from the study phase, Pre-Phase-A (a.k.a., “Cycle 6”) design to NASA Phase A formulation, a significant change to the IOA was initiated; including moving the tertiary mirror from the instrument package to a unified three-mirror anastigmat (TMA) placement, that provides a wide 0.28-sq° instrumented field of view to the Wide Field Instrument (WFI). In addition, separate relays from the primary and secondary mirror feed the Wide Field Instrument (WFI) and Coronagraph Instrument (CGI). During commissioning the telescope is aligned using wavefront sensing with the WFI[2]. A parametric and Monte-Carlo analysis was performed, which determined that alignment compensation with the secondary mirror alone degraded performance in the other instruments. This led to the addition of a second compensator in the WFI optical train to alleviate this concern. This paper discusses the trades and analyses that were performed and resulting changes to the WFIRST telescope architecture.

Paper Details

Date Published: 22 August 2017
PDF: 10 pages
Proc. SPIE 10377, Optical System Alignment, Tolerancing, and Verification XI, 103770E (22 August 2017); doi: 10.1117/12.2280333
Show Author Affiliations
John Hagopian, Lambda Consulting (United States)
Advanced NanoPhotonics, Inc. (United States)
Nerses Armani, SGT, Inc. (United States)
Lisa Bartusek, NASA Goddard Space Flight Ctr. (United States)
Tom Casey, SGT, Inc. (United States)
Dave Content, NASA Goddard Space Flight Ctr. (United States)
Yves Conturie, Harris Corp. (United States)
Guangjun Gao, Sigma Space Corp. (United States)
Alden Jurling, NASA Goddard Space Flight Ctr. (United States)
Cathy Marx, NASA Goddard Space Flight Ctr. (United States)
Joe Marzouk, Sigma Space Corp. (United States)
Bert Pasquale, NASA Goddard Space Flight Ctr. (United States)
J. Scott Smith, NASA Goddard Space Flight Ctr. (United States)
Hong Tang, Jet Propulsion Lab. (United States)
Arthur Whipple, Conceptual Analytics, LLC (United States)

Published in SPIE Proceedings Vol. 10377:
Optical System Alignment, Tolerancing, and Verification XI
José Sasián; Richard N. Youngworth, Editor(s)

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