Authors

N. Jeremy Kasdin, David N. Spergel, Robert Vanderbei, Stuart Shaklan, Douglas P. Lisman, Dmitry Savransky, Eric Cady, Remi Soummer

Affiliations

Princeton University, Jet Propulsion Laboratory, Space Telescope Science Institute

Abstract

Free flying occulters are an attractive option as a space mission architecture for imaging exosolar planets, particular ones in the habitable zone. Their appeal is two-fold: the inner working angle is largely decoupled from telescope diameter and, because they suppress starlight before entering the telescope, there is no need for wavefront control. We present the basic operating principles of occulters for high-contrast, including preliminary stationkeeping simulations, and a manufacturing approach being studied as part of NASA’s Technology Demonstration for Exoplanet Missions. Our main focus is a comparison of mission architectures employing occulters at varying scales: large flagship observatories (THEIA, NWO), existing large aperture telescopes (JWST), small dedicated telescopes (O3), and small general purpose telescopes (such as a dark energy mission like EUCLID). THEIA, the Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy, is a multi-instrument space-telescope concept employing a 4-m diffraction-limited telescope operating at UV and Visible wavelengths that was developed as part of NASAs Astrophysics Strategic Mission Concept Studies in 2009 and presented to the US Academy’s decadal survey review, Astro2010. By combining the telescope with a roughly 40 m occulter, operating at two different telescope-occulter separations, planets as small as Earth can be characterized over a broad band, including R>70 spectra. O3, the Occulting Ozone Observatory, is a smaller mission costing less than $1B that uses a 1 to 2 m telescope combined with a roughly 30 m occulter. O3 is capable of time-resolved photometry over 8 bands, focusing on biomarkers, such as detecting the strong ozone feature, and surface characterization. It also provides the capability for enough repeat visits to support orbit determination. We will compare the science yield and architecture and how different coronagraph and occulter approaches perform at these different mission scales.