ACCESS: a NASA mission concept study of an Actively Corrected Coronagraph for Exoplanet System Studies

ACCESS (Actively-Corrected Coronagraph for Exoplanet System Studies) develops the science and engineering case for an investigation of exosolar giant planets, super-earths, exo-earths, and dust/debris fields that would be accessible to a medium-scale NASA mission. The study begins with the observation that coronagraph architectures of all types (other than the external occulter) call for an exceptionally stable telescope and spacecraft, as well as active wavefront correction with one or more deformable mirrors (DMs). During the study, the Lyot, shaped pupil, PIAA, and a number of other coronagraph architectures will all be evaluated on a level playing field that considers science capability (including contrast at the inner working angle (IWA), throughput efficiency, and spectral bandwidth), engineering readiness (including maturity of technology, instrument complexity, and sensitivity to wavefront errors), and mission cost so that a preferred coronagraph architecture can be selected and developed for a medium-class mission.