The Roman Space Telescope coronagraph technology demonstration: current status and relevance to future missions

The Nancy Grace Roman Space Telescope (formerly WFIRST) will be launched in the mid-2020s with an onboard Coronagraph Instrument which will serve as a technology demonstrator for exoplanet direct imaging. The Roman Coronagraph will be capable of detecting and characterizing exoplanets and circumstellar disks in visible light at an unprecedented contrast level of similar to 10(-8) or better at small separations. Such a contrast level, which is 2 to 3 orders of magnitude better than state-of-the-art visible or near-infrared coronagraphs, raises entirely new challenges that will be overcome using a combination of hardware, calibration and data processing. In particular, the Roman Coronagraph will be the first space-based coronagraphic instrument with active low- and high-order wavefront control through the use of large-format (48x48) deformable mirrors, and its electron-multiplying Charge Coupled Device (EMCCD) detector will enable faint signal detection in photon-counting mode. The Roman Coronagraph successfully passed its critical design review in April 2021 and its system integration review in June 2022. It is now well on its path to demonstrate many core technologies at the levels required for a future exo-Earth direct imaging mission.