X-array aperture configuration in planar or non-planar spacecraft formation for Darwin/TPF-I candidate architectures

Oswald Wallner; Klaus Ergenzinger; Reinhold Flatscher; Ulrich Johann

doi:10.1117/12.733820

19 September 2007 X-array aperture configuration in planar or non-planar spacecraft formation for Darwin/TPF-I candidate architectures

Oswald Wallner, Klaus Ergenzinger, Reinhold Flatscher, Ulrich Johann

Author Affiliations +

Proceedings Volume 6693, Techniques and Instrumentation for Detection of Exoplanets III; 66930U (2007) https://doi.org/10.1117/12.733820
Event: Optical Engineering + Applications, 2007, San Diego, California, United States

Abstract

The missions DARWIN and TPF-I (Terrestrial Planet Finder-Interferometer) aim at the search and analysis of terrestrial exo-planets orbiting nearby stars. The major technical challenge is the huge contrast ratio and the small angular separation between star and planet. The observational method to be applied is nulling interferometry. It allows for extinguishing the star light by several orders of magnitude and, at the same time, for resolving the faint planet. The fundamental performance of the nulling interferometer is determined by the aperture configuration, the effective performance is driven by the actual instrument implementation. The x-Array, an aperture configuration with 4 telescopes allowing for phase chopping and decoupling of the nulling and imaging properties, provides highest instrument performance. The scientific goals necessitate an instrument setup of high efficiency and utmost symmetry between the beams concerning optical path length, beam profile and state of polarization. Non-planar spacecraft formations allow for a simpler spacecraft design which comes at the cost of inherent constellation and beam asymmetry, of increased complexity of the beam relay optics and of instrumental errors synchronous to the planet signal demodulation frequency. Planar formations allow for perfect efficiency and symmetry but need deployable structures for the secondary mirror and the sunshield due to launcher accommodation constraints. We present a discussion of planar and non-planar implementations of the x-Array aperture configuration and identify for both the critical items and design drivers. We compare the achievable instrument performance and point out the constraints for each spacecraft formation.

Citation Download Citation

Oswald Wallner, Klaus Ergenzinger, Reinhold Flatscher, and Ulrich Johann "X-array aperture configuration in planar or non-planar spacecraft formation for Darwin/TPF-I candidate architectures", Proc. SPIE 6693, Techniques and Instrumentation for Detection of Exoplanets III, 66930U (19 September 2007); https://doi.org/10.1117/12.733820

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