2015.A.1.5. Centaur: A scientific and technology pathfinder for direct imaging exoplanet missions

Author(s)

Eduardo Bendek (1)
Ruslan Belikov (1)
Rodolphe De Rosee (1)
Peter Klupar (1)
Sasha Weston (2)

NASA Ames, United States of America
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Session

A.1

Keywords

Coronagraph, exoplanets, direct imaging, telescope

Abstract

Centaur is a scientific and technology pathfinder for NASA’s planned series of direct-imaging exoplanet detection missions. Centaur’s objective is to advance existing Starlight Suppression Systems technologies from TRL-5 to TRL-7 in preparation for larger and more capable direct imaging missions. Centaur accomplishes this objective by observing the exozodiacal light in visible bands of two nearby star systems, in particular αCen A & B and εEri. Directly imaging and characterizing planets around nearby stars is becoming an increasingly important scientific goal as the planet occurrence rate increases with the latest results indicating 0.79 planets per star are smaller than 5 Earth sizes and have orbital periods between 50 and 300 days. In particular, for exo-Earths (ηEarth) in the Habitable Zone (HZ) this rate could be as high as 55% per star for ranges of 0.5-2 Earth sizes. As a result, the likelihood of finding a planet 5 times the size of Earth’s radius or smaller around any of the 5 closest F, G, K stars is almost 1; and of finding an exo-Earth in the HZ of those stars is approximately 95%.

A particularly interesting case is the Alpha Centauri A & B binary system. Its HZ extends from 0.7” to 1.6” and 0.4” to 0.95”, respectively, and where an Earth-like planet has a contrast ratio of 1×10-10 making it accessible using small-aperture telescopes.

Centaur is a single-instrument mission employing a stand-alone, compact, high-performance 15cm aperture coronagraphic telescope, integrated with an off-the-shelf 27U small satellite bus. We expect Centaur to achieve a raw contrast of 10-7 and a post-processing enhancement factor of 100 using Orbital Differential Imaging reaching 10-9 total contrast for point sources and a factor of 20 on extended sources such disks by rolling the S/C.

Centaur has a robust design that allows a graceful mission downscope if technical problems are encountered, Specifically, we add a calibration source to enable on-orbit validation of the DM, the new compact controller, the science camera, and the wavefront control algorithm even if the bus does not meet the pointing requirements.

The Centaur Project is a 4-year effort that designs, builds, and launches a small satellite based on a rapid, low-cost development plan that is synergistically aligned with NASA ARC’s areas of expertise: cubesats, PIAA coronagraphs, and multi-star wavefront control.