The NIRSpec instrument on the James Webb Space Telescope (JWST) brings the first multi-object spectrograph (MOS) into space, enabled by a programmable Micro Shutter Array (MSA) of ~250,000 individual apertures. During the 6-month Commissioning period, the MSA performed admirably, completing ~800 reconfigurations with an average success rate of ~96% for commanding shutters open in science-like patterns. We show that 82.5% of the unvignetted shutter population is usable for science, with electrical short masking now the primary cause of inoperable apertures. In response, we propose a plan to recheck existing shorts during nominal operations, which is expected to reduce the number of affected shutters. We also present a full assessment of the Failed Open and Failed Closed shutter populations, which both show a marginal increase in line with predictions from ground testing. We suggest an amendment to the Failed Closed shutter flagging scheme to improve flexibility for MSA configuration planning. Overall, the NIRSpec MSA performed very well during Commissioning, and the MOS mode was declared ready for science operations on schedule.
Cite
@article{arxiv.2208.04673,
title = {In-flight performance of the NIRSpec Micro Shutter Array},
author = {Timothy D. Rawle and Giovanna Giardino and David E. Franz and Robert Rapp and Maurice te Plate and Christian A. Zincke and Yasin M. Abul-Huda and Catarina Alves de Oliveira and Katie Bechtold and Tracy Beck and Stephan M. Birkmann and Torsten Böker and Ralf Ehrenwinkler and Pierre Ferruit and Dennis Garland and Peter Jakobsen and Diane Karakla and Hermann Karl and Charles D. Keyes and Robert Koehler and Nimisha Kumari and Nora Lützgendorf and Elena Manjavacas and Anthony Marston and S. Harvey Moseley and Peter Mosner and James Muzerolle and Patrick Ogle and Charles Proffitt and Elena Sabbi and Marco Sirianni and Glenn Wahlgren and Emily Wislowski and Raymond H. Wright and Chi Rai Wu and Peter Zeidler},
journal= {arXiv preprint arXiv:2208.04673},
year = {2022}
}
Comments
15 pages, 6 figures, to appear in Proceedings of SPIE conference "Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave"