Optical alignment of contamination-sensitive Far-Ultraviolet spectrographs for Aspera SmallSat mission
Abstract
Aspera is a NASA Astrophysics Pioneers SmallSat mission designed to study diffuse OVI emission from the warm-hot phase gas in the halos of nearby galaxies. Its payload consists of two identical Rowland Circle-type long-slit spectrographs, sharing a single MicroChannel plate detector. Each spectrograph channel consists of an off-axis parabola primary mirror and a toroidal diffraction grating optimized for the 1013-1057 Angstroms bandpass. Despite the simple configuration, the optical alignment/integration process for Aspera is challenging due to tight optical alignment tolerances, driven by the compact form factor, and the contamination sensitivity of the Far-Ultraviolet optics and detectors. In this paper, we discuss implementing a novel multi-phase approach to meet these requirements using state-of-the-art optical metrology tools. For coarsely positioning the optics we use a blue-laser 3D scanner while the fine alignment is done with a Zygo interferometer and a custom computer-generated hologram. The detector focus requires iterative in-vacuum alignment using a Vacuum UV collimator. The alignment is done in a controlled cleanroom facility at the University of Arizona.
Cite
@article{arxiv.2407.15391,
title = {Optical alignment of contamination-sensitive Far-Ultraviolet spectrographs for Aspera SmallSat mission},
author = {Aafaque R. Khan and Erika Hamden and Haeun Chung and Heejoo Choi and Daewook Kim and Nicole Melso and Keri Hoadley and Carlos J. Vargas and Daniel Truong and Elijah Garcia and Bill Verts and Fernando Coronado and Jamison Noenickx and Jason Corliss and Hannah Tanquary and Tom Mcmahon and Dave Hamara and Simran Agarwal and Ramona Augustin and Peter Behroozi and Harrison Bradley and Trenton Brendel and Joe Burchett and Jasmine Martinez Castillo and Jacob Chambers and Lauren Corlies and Greyson Davis and Ralf-Jürgen Dettmar and Ewan Douglas and Giulia Ghidoli and Alfred Goodwin and Walter Harris and Carl Hergenrother and J. Christopher Howk and Miriam Keppler and Nazende Ipek Kerkeser and John N. Kidd and Jessica S. Li and Gabe Noriega and Sooseong Park and Ryan Pecha and Cork Sauve and David Schiminovich and Sanford Selznick and Oswald Siegmund and Rebecca Su and Sumedha Uppnor and Jacob Vider and Ellie Wolcott and Naomi Yescas and Dennis Zaritsky},
journal= {arXiv preprint arXiv:2407.15391},
year = {2024}
}
Comments
Manuscript submitted for Proceedings of Astronomical Telescopes + Instrumentation 2024, Paper no. 13093-9