The Exo-S probe class starshade mission

• Main Authors: Seager, Sara (Contributor), Turnbull, Margaret (Author), Sparks, William (Author), Thomson, Mark (Author), Shaklan, Stuart B. (Author), Roberge, Aki (Author), Kuchner, Marc (Author), Kasdin, N. Jeremy (Author), Domagal-Goldman, Shawn (Author), Cash, Webster (Author), Warfield, Keith (Author), Lisman, Doug (Author), Scharf, Dan (Author), Webb, David (Author), Trabert, Rachel (Author), Martin, Stefan (Author), Cady, Eric (Author), Heneghan, Cate (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor)
• Format: Article
• Language: English
• Published: SPIE, 2017-01-11T21:45:13Z.
• Subjects: Article
• Online Access: Get fulltext

 Exo-S is a direct imaging space-based mission to discover and characterize exoplanets. With its modest size, Exo-S bridges the gap between census missions like Kepler and a future space-based flagship direct imaging exoplanet mission. With the ability to reach down to Earth-size planets in the habitable zones of nearly two dozen nearby stars, Exo-S is a powerful first step in the search for and identification of Earth-like planets. Compelling science can be returned at the same time as the technological and scientific framework is developed for a larger flagship mission. The Exo-S Science and Technology Definition Team studied two viable starshade-telescope missions for exoplanet direct imaging, targeted to the $1B cost guideline. The first Exo-S mission concept is a starshade and telescope system dedicated to each other for the sole purpose of direct imaging for exoplanets (The "Starshade Dedicated Mission"). The starshade and commercial, 1.1-m diameter telescope co-launch, sharing the same low-cost launch vehicle, conserving cost. The Dedicated mission orbits in a heliocentric, Earth leading, Earth-drift away orbit. The telescope has a conventional instrument package that includes the planet camera, a basic spectrometer, and a guide camera. The second Exo-S mission concept is a starshade that launches separately to rendezvous with an existing on-orbit space telescope (the "Starshade Rendezvous Mission"). The existing telescope adopted for the study is the WFIRST-AFTA (Wide-Field Infrared Survey Telescope Astrophysics Focused Telescope Asset). The WFIRST-AFTA 2.4-m telescope is assumed to have previously launched to a Halo orbit about the Earth-Sun L2 point, away from the gravity gradient of Earth orbit which is unsuitable for formation flying of the starshade and telescope. The impact on WFIRST-AFTA for starshade readiness is minimized; the existing coronagraph instrument performs as the starshade science instrument, while formation guidance is handled by the existing coronagraph focal planes with minimal modification and an added transceiver.