The COROT (Convection Rotation à Transits planétaires / Convection Rotation and
planetary Transits) instrument, an afocal telescope equipped by four CCD detectors, was
put on a Proteus platform and launched in
late 2006 for an at least 2 and 1/2 years mission.
COROT has two scientific objectives:
- The detection and the study of stars vibrations (stellar seismology).
- The search for extrasolar planets and more particularly the telluric planets.
This astrophysical space experiment will enable to study, in two application domains,
phenomena and objects never observed to this day.
The payload main components are:
- The afocal telescope is at first constituted of two parabolic mirrors allowing to
decrease 3 times the equivalent entry pupil diameter, then 6 dioptric lens allowing to
have a 1.1 m focal length.
The field of view is a square of 2.8 × 2.8°, half for the seismology mission, the other
half for the exoplanet mission.
- The focal plane detectors are 4 CCDs and working in the visible in the MPP mode. They
are installed in the focal box, which temperature is -40° C with a variation lower than
0.05° C/hour.
For the seismology mission, the image spot for a star will be spread out on about 400
pixels, exposure time of 1 second,
A prism, allowing to get a color image of the stars, will be installed before the
exoplanet field. It will enable to distinguish the stellar activities of a planetary
transit, for the brightest stars.
- The external baffle was designed to have a reduction coefficient of 10-13. Thus, the
maximum number of photons coming from the Earth is 0,2 photon/pixel/second, if the Earth
is at least 20° from the telescope axis. This baffle is protected during the launch by a
one shot shutter.
COROT stopped sending data on 2. November 2012 due to a computer failure. Attempts to revive the observatory failed and the mission was terminated in June 2013. The satellite was finally switched off on 17 June 2014.
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