The Near-Infrared Imaging Channel for the Euclid Dark Energy Mission : Development of Critical Opto-Mechanical Components and an Instrument Calibration Concept

Abstract

This thesis describes a number of instrumentation and mission design developments performed to prepare the European Space Agency’s (ESA’s) Euclid Mission. This space-based mission will enable unprecedented experimental probes of the nature of dark energy. As the Near-Infrared Photometry Scientist – one of three Instrument Scientists within the Euclid Consortium – my work focused on the mission’s near-infrared photometric channel, which is required for the photometric redshift measurements of the ~1.5 billion galaxies within the large Euclid imaging survey. This thesis addresses and solves a range of specific problems relating to implementation of this channel, with the ultimate goal of proving mission feasibility during the selection process of ESA’s Cosmic Vision Program. To that end, this thesis details requirement breakdowns and error budgets used to translate scientific requirements into lower level instrument requirements. The performance validation of the baseline implementation of the mission against high level requirements has formed an important part of the mission verification process; those applicable to the photometric channel are presented in this thesis. I have also developed a calibration strategy to meet the channel’s stringent high level calibration requirement. This includes specific work on optimizing the survey strategy for the retrospective calibration of the survey-wide dataset and also hardware development relating to a potential implementation of an internal flat-field calibration source. An assessment of the channel’s critical, single-point-failure filter wheel mechanism – which is needed to allow multi-band near-infrared photometry – is also detailed. Much of this effort has been incorporated into official Euclid documentation that has formed the basis of the Euclid Consortium’s response to the Cosmic Vision Program selection process. The baseline implementation of the near-infrared photometric channel, the performance of which was under my stewardship, meets all the high level science requirements.