Year: 2017
Type: conference-paper
Abstract: Alcatel Space has been responsible for a feasibility study contract, awarded by the European Space Agency, and dedicated to the definition of preliminary interferometric concepts for the direct detection and characterisation of exo-planets associated with nearby stars. The retained concept is a six free-flyer-telescope interferometer, with a variable baseline ranging from 50 to 500 m. The collected wavefronts are combined on a 7th free-flying hub satellite at the centre of the array, and the observations are performed in the thermal Infra-Red spectral band. The latter choice is made for two reasons : firstly, the wavelength providing optimal contrast between the planetary and stellar (background) signals is approximately 10μm; secondly, the spectral features of interest for the detection of life as we know it (CO2, H2O, O3 , CH4 ... ) lie in the band between 6 and 18 μm. The system requirements for such an instrument are very severe, owing to the physical nature of the mission concept; i.e. that of a coronographic stellar interferometer: in order to achieve satisfactory extinction of the unwanted flux generated by the central star, such a concept will impose the control of optical pathlength differences between telescopes to within a small fraction of a wavelength, milli-arcsec pointing stabilities, 10-3 amplitude equalisation, achromatic check-shifts of some beams with respect to the others, and the use of passively cooled cryogenic telescopes.
DOI: 10.1117/12.2307876
Authors: Eric Thomas, Thierry Viard, Glenn Lund, Michel Vacance
Institution: Alcatel-Lucent (France)
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2768330717