Performance analysis of a space-based multiple-telescope nulling interferometer for DARWIN

Abstract

The European Space Agency’s infrared space interferometer DARWIN is dedicated to the investigation of Earth-like extrasolar planets orbiting bright stars. A multi-aperture interferometer fed by free-flying telescopes allows spectroscopic analysis of the weak planet signal which could give hints on the possibility of the existence of Earth-like life. However, for a Sun/Earth-like constellation at an interstellar distance of some 50 light years, a star light suppression of about 60 dB is required to make the weak planet signal visible. In this paper we investigate the nulling capability of a space-based Robin Laurance interferometer in the case of stochastic disturbances of the array geometry and of stochastic alignment errors of the optical components, which both will be actively controlled. Mismatch of amplitude transmission, optical path length, and polarization transmission among the interferometer arms is taken into account.