The Roman Space Telescope Wide Field Instrument - Benjamin Cromey

The Roman Space Telescope Wide Field Instrument (WFI) will enable revolutionary advancements in astronomical survey science. Instrument sensitivity spans the 0.5–2.3 μm spectral range with a significant increase in field of view, detector sensitivity, and angular resolution compared to existing observatories. The science of the observatory drove tight stability requirements, and necessitated an array of different optical elements within WFI to switch between imaging at different wavelengths, and using two slitless spectroscopic elements. The science also drove the need for an uncommonly high level of detector calibration, requiring an on-board calibration system supported by unique optics, as well as precise stray light mitigation. In 2024, WFI completed its year-long integration and test campaign as a full instrument, including multiple environmental tests, enabling its performance to be studied in operational temperature conditions. This presentation summarizes several key optical performance aspects of the instrument and how they were verified, including bandpass filter wavefront error, stray light control, and optomechanical alignment. The results demonstrate that the WFI is ready to help transform astrophysics as part of the next NASA flagship observatory.