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Proceedings Paper

The JWST MIRI FM wheel mechanisms characterisation for open loop drive
Author(s): Örs Hunor Detre; Ulrich Grözinger; Oliver Krause; Friedrich Müller; Silvia Scheithauer
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Paper Abstract

The high reliability of the mechanisms of any space instrument is one of the most critical and challenging requirements. This is even more pronounced in the case of cryogenic instruments, such as the Mid-Infrared Instrument (MIRI) to be flown on the James Webb Space Telescope (JWST) – which will be cooled down to below 7 K. MIRI hosts three wheel mechanisms for filter, grating and dichroic selection. All of them have an open loop torque drive and thus the precise characterisation of the mechanisms and their motors is fundamental to achieve minimum heat load and maximum reliability of the mechanism movements over the lifetime. In this paper we present the overview of the characterisation and verification of the MIRI wheel mechanisms. Our method is based on measuring back EMF voltages generated by the two phase cold redundant motors of the wheel mechanisms after they had been fully integrated into the MIRI optical module. We present the analysis of the data and the resulting performance increase. We discuss the optimisation of the open loop drive, as well as the verification of the measurement results and the physical model of the motors and mechanisms.

Paper Details

Date Published: 13 September 2012
PDF: 11 pages
Proc. SPIE 8450, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II, 84501Z (13 September 2012); doi: 10.1117/12.926661
Show Author Affiliations
Örs Hunor Detre, Max Planck Institute for Astronomy (Germany)
Ulrich Grözinger, Max Planck Institute for Astronomy (Germany)
Oliver Krause, Max Planck Institute for Astronomy (Germany)
Friedrich Müller, Max Planck Institute for Astronomy (Germany)
Silvia Scheithauer, Max Planck Institute for Astronomy (Germany)


Published in SPIE Proceedings Vol. 8450:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II
Ramón Navarro; Colin R. Cunningham; Eric Prieto, Editor(s)

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