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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. |
Space telescopes
Telescopes
Interferometers
Sensors
Mirrors
Space operations
Stars
