Optical Design and Status of the Large Ultra-Violet Optical Infrared Surveyor (LUVOIR)

"In preparation for the Astrophysics 2020 Decadal Survey NASA's Goddard Space Flight Center is studying a segmented aperture telescope with broad astrophysics, solar system, and exoplanet science capability called the Large Ultra-Violet Optical Infrared Surveyor (LUVOIR). This telescope design incorporates many heritage design concepts from the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and the Wide-field Infrared Survey Telescope (WFIRST). This includes similar ultraviolet instrumentation from HST, deployable segmented optics from JWST, and high-contrast coronagraph technology from WFIRST. Several optical design trades were completed to maximize the science product while maintaining reasonable packaging and fabrication constraints. Other technology developments such as freeform optics, UV enhanced coatings, coronagraph design, and ultra-stable mirrors are being studied to further improve the observatory performance

A Future Large-Aperture UVOIR Space Observatory: Key Technologies and Capabilities

We present the key technologies and capabilities that will enable a future, large-aperture ultravioletopticalinfrared (UVOIR) space observatory. These include starlight suppression systems, vibration isolation and control systems, lightweight mirror segments, detector systems, and mirror coatings. These capabilities will provide major advances over current and near-future observatories for sensitivity, angular resolution, and starlight suppression. The goals adopted in our study for the starlight suppression system are 10-10 contrast with an inner working angle of 20 milliarcsec and broad bandpass. We estimate that a vibration and isolation control system that achieves a total system vibration isolation of 140 dB for a vibration-isolated mass of 5000 kg is required to achieve the high wavefront error stability needed for exoplanet coronagraphy. Technology challenges for lightweight mirror segments include diffraction-limited optical quality and high wavefront error stability as well as low cost, low mass, and rapid fabrication. Key challenges for the detector systems include visible-blind, high quantum efficiency UV arrays, photon counting visible and NIR arrays for coronagraphic spectroscopy and starlight wavefront sensing and control, and detectors with deep full wells with low persistence and radiation tolerance to enable transit imaging and spectroscopy at all wavelengths. Finally, mirror coatings with high reflectivity ( 90), high uniformity ( 1) and low polarization ( 1) that are scalable to large diameter mirror substrates will be essential for ensuring that both high throughput UV observations and high contrast observations can be performed by the same observatory