Optical design considerations for the terrestrial planet finder - coronagraph mission : Optical telescope assembly

The Terrestrial Planet Finder-Coronagraph (TPF-C) is a NASA exploration mission to directly detect and characterize terrestrial exoplanets at visible wavelengths. The TPF-C observatory must be able to distinguish a planet that is more than 10 orders of magnitude fainter than its parent star at a separation of 75 milli-arc-seconds (mas). Coronagraphic detection requires a large aperture telescope to resolve the exoplanet from its star, and extreme stability during detection and characterization observations. This paper discusses the requirements and trade studies leading to the current baseline optical design for the TPF-C telescope. The current baseline design is summarized and its prescription is presented.