The HabEx Observatory: A Coronagraph and a Starshade for Exoplanet Science

The National Academies' 2020 Decadal Survey on Astronomy and Astrophysics will provide a broad vision for future science in these disciplines and the Habitable Exoplanet Observatory (HabEx) is one of four major observatory missions extensively studied in preparation for the survey. HabEx is a space telescope with a 4 m diameter primary mirror, carrying a complement of two general astrophysics camera/spectrographs with coverage from the far UV to the near infrared as well as two key instruments for exoplanet science. These exoplanet instruments consist of a high performance coronagraph (that places stringent demands on the overall observatory design and performance) and a remote (tens of megameters distant) formation flying occulter, consisting of a 52 m diameter starshade deployed from a second launch vehicle. This paper discusses the specific features of the observatory that permit high contrast coronagraphy at the 10−10 contrast level and the design considerations for the coronagraph itself. The starshade design is discussed in the context of the current technology development activities being undertaken by NASA to bring starshade readiness up to TRL5.