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Image Guider Subsystem Analysis for the GHAPS ProjectThe Gondola for High-Altitude Planetary Science (GHAPS) project is a balloon-borne astronomical observatory designed operate in the UV, Visible, and near-mid IR spectral region. The GHAPS Optical Telescope Assembly (OTA) is designed around a one meter aperture narrow field-of-view telescope with near diffraction limited performance. GHAPS will utilize Wallops Arc-Second Pointing System (WASP) for pointing the OTA with an accuracy of 1 arc second or better. WASP relies heavily on a self-contained star tracker assembly to determine the OTA line of sight. Preliminary structural analysis indicated that potential misalignments could be present between the OTA line of sight and the star tracker FOV center during the expected flight conditions that could compromise GHAPS pointing accuracy. An analysis is presented that estimates the worst case long-term (or bias) pointing misalignments for the GHAPS opto-mechanical configuration, examines the need for additional hardware to correct pointing errors, and determines the best hardware and software implementation to do so. The analysis includes the development of a photometric model to predict the limiting magnitude of a GHAPS Facility Guide System (FGS) for a variety of image sensor technologies from visible to mid IR. FGS system performance is estimated using star magnitude and spectral data from actual star catalogs for more realistic predictions. Based on expected performance and other factors, such as size, weight, power, and cost, a final recommendation is made for the GHAPS configuration.
Document ID
20180005329
Acquisition Source
Glenn Research Center
Document Type
Presentation
Authors
Lewis, Michael
(NASA Glenn Research Center Cleveland, OH, United States)
Juergens, Jeffrey
(NASA Glenn Research Center Cleveland, OH, United States)
Aretskin-Hariton, Eliot
(NASA Glenn Research Center Cleveland, OH, United States)
Woodruff, Robert
(Woodruff (Robert) Boulder, CO, United States)
Date Acquired
September 17, 2018
Publication Date
June 10, 2018
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GRC-E-DAA-TN57408
Meeting Information
Meeting: SPIE Astronomical Telescopes + Instrumentation
Location: Austin, TX
Country: United States
Start Date: June 10, 2018
End Date: June 15, 2018
Sponsors: International Society for Optical Engineering
Funding Number(s)
CONTRACT_GRANT: NNC16CA44C
WBS: WBS 33676301.05.02.04.10.01
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Telescope Guider
Image Guider
Star Tracker
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