WFIRST wide field instrument optical mechanical assembly design overview

The Wide Field Infrared Survey Telescope (WFIRST), NASA’s next decadal astrophysics observatory, will enable advances in astrophysics by providing a large-scale survey capability in infrared wavelengths. The observatory is designed to capture data that will allow astronomers to unlock the mysteries of the universe, answering high-priority scientific questions related to the evolution of the universe and the habitability of exoplanets. Using a 2.4 m (7.9 ft) primary mirror, WFIRST will capture comparable quality images to the Hubble Space Telescope, but with more than 100 times the field of view, enabling the observatory to conduct comprehensive and efficient surveys of the infrared sky. Scientists estimate WFIRST has the potential to examine a billion galaxies over the course of its mission. Ball Aerospace was selected as NASA’s partner to design and develop the Wide Field Instrument (WFI) Opto-Mechanical Assembly for the WFIRST mission. The optical-mechanical assembly, which includes the optical bench, thermal control system, precision mechanisms, optics, electronics, and the relative calibration system, provides the stable structure and thermal environment that enables the wide-field, high quality observations of WFI. Ball's innovative design uses heritage hardware to unfold the incoming light, providing cost and schedule savings to the mission. In this paper, we present an overview of the WFI design, which completed its preliminary design review in June 2019. The overview includes a discussion of the design process, including several of the trade studies completed that led to the unfolded optical path architecture for the instrument design. The current state of the design is shown.