Phase Occulted Nulling Coronagraph: Instrument Technology Advancement

The Phase Occulted Nulling Coronagraph (PONC), invented by R. Lyon, is a viable and game-changing approach for future arbitrary shaped aperture exoplanet science missions. It enables direct exoplanet imaging with a filled, obscured or segmented telescope due to its field-dependent pupil plane rejection of starlight (nulling) . In FY16 we plan to fabricate and test a set of prototype PONC optics as a proof of the principle.The projects full objective is to demonstrate that a given PONC optical design can be fabricated using current state of the art techniques. This serves to demonstrate one of the key remaining issues with the PONC approach, i.e. that the aspheric surfaces of the 4 PONC optics can be fabricated, aligned, tested and achieve, and hold, high contrast imaging. This advances the PONC optics from a simulation (TRL-2) to a lab prototype (TRL-3). Ultimately the PONC optics will be tested in GSFC’s laboratory visible nulling coronagraph (VNC).  GSFC is the lead center for the PONC, it was invented here, and GSFC has a vested interest in it as a potential game-changing exoplanet technology. The science payoff is its ability to (i) image/characterize exoplanets with a segmented aperture telescope, (ii) over a wide field of view, and (iii) with less demanding telescope stability tolerances. The successful fabrication and demonstration of the PONC optics results in improved cost efficiency since our approach relaxes the stability tolerances of segmented telescopes, eases requirements on on-orbit operations and ground testing, resulting in a lower cost mission with the same science yield.