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Reconstruction of the NuSTAR point spread function using single-laser metrology

Earnshaw, Hannah P. and Madsen, Kristin K. and Forster, Karl and Grefenstette, Brian W. and Brightman, Murray and Zoglauer, Andreas and Harrison, Fiona (2022) Reconstruction of the NuSTAR point spread function using single-laser metrology. Journal of Astronomical Telescopes, Instruments, and Systems, 8 (1). Art. No. 014009. ISSN 2329-4124. doi:10.1117/1.jatis.8.1.014009.

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We describe a method by which the metrology system of the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray space observatory, which uses two lasers to characterize the relative motion of the optics and focal plane benches, can be approximated should one laser fail. The two benches are separated by a 10-m-long rigid mast that undergoes small amounts of thermal flexing that needs to be compensated for to produce a nonblurred image. We analyze the trends of mast motion by archival observation parameters to discover whether the mast motion in future observations can be predicted. We find that, using the solar aspect angle, observation date, and orbital phase, we can simulate the motion of one laser by translating the track produced by the other and applying modifications to the resulting mast aspect solution, allowing for the reconstruction of a minimally distorted point spread function in most cases. We will implement the generation of simulated mast files along with the usual NuSTAR data reduction pipeline for contingency purposes. This work has implications for reducing the risk of implementing laser metrology systems on future missions that use deployable masts to achieve the long focal lengths required in high-energy astronomy by mitigating the impact of a metrology laser failure in the extended phase of a mission.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Earnshaw, Hannah P.0000-0001-5857-5622
Madsen, Kristin K.0000-0003-1252-4891
Forster, Karl0000-0001-5800-5531
Grefenstette, Brian W.0000-0002-1984-2932
Brightman, Murray0000-0002-8147-2602
Zoglauer, Andreas0000-0001-9067-3150
Harrison, Fiona0000-0003-2992-8024
Additional Information:© 2022 The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Paper 21127 received Oct. 7, 2021; accepted for publication Feb. 8, 2022; published online Feb. 22, 2022. We thank our anonymous reviewers for helpful comments that improved this paper. This work was supported under NASA Contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology.
Group:Astronomy Department, Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
Subject Keywords:laser metrology; space telescopes; point spread functions; x-rays
Issue or Number:1
Record Number:CaltechAUTHORS:20220301-900015000
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Official Citation:Hannah P. Earnshaw, Kristin K. Madsen, Karl W. Forster, Brian W. Grefenstette, Murray Brightman, Andreas Zoglauer, and Fiona A. Harrison "Reconstruction of the NuSTAR point spread function using single-laser metrology," Journal of Astronomical Telescopes, Instruments, and Systems 8(1), 014009 (22 February 2022).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113665
Deposited By: George Porter
Deposited On:02 Mar 2022 00:44
Last Modified:02 Mar 2022 00:44

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