Gaia: focus, straylight and basic angle [IMA]

http://arxiv.org/abs/1608.00045


The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations
Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement.
In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.

Read this paper on arXiv…

A. Mora, M. Biermann, A. Bombrun, et. al.
Tue, 2 Aug 16
9/80

Comments: 17 pages, 17 figures. To appear in SPIE proceedings 9904-78. Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave