The COROT mission is dedicated to stellar seismology and search for telluric extra -solar planets. The development is led by CNES in association with French laboratories (LESIA, LAM and IAS) and several European partners (Germany, Belgium, Austria, Spain, ESA and Brasilia). The COROT seismology program will measure periodic variations with amplitude of 2.10-6 of the photon flux emitted by bright stars. The COROT exoplanet program will detect the presence of exoplanets using the radiometric occultation method. The need is to detect photons flux variations about 7.10-4 for one hour integration time. Such performance will permit to detect occultations on a very large number of stars : magnitude between 12 and 15.5. The satellite Preliminary Design Review has been held on January 2004 while the instrument is already in development phase with a Critical Design Review in April 2004 and a delivery of the flight model in March 2005. The launch is scheduled in June 2006. This paper recalls the mission, describes the payload and its main noise performances.
Radiation is a major issue for satellite development, especially when using detectors, either for the mission itself, or for platform sensors. This paper will give CNES experience in the effects of radiations on detector and mission performances. Data from several satellites is presented (Earth observation, Astronomy, star trackers). We will make comparison between this data, to try to determine common behaviours. We will finish by describing the mitigation techniques against radiation effects.
COROT is a mission of the CNES space agency, to be launched in 2005 in a Polar orbit. Its main goals are the search of stellar oscillation and the exoplanet detection. Five star fields chosen close to the galactic plane and in the opposite direction will be observed with an high photometric stability. Four 2048x2048 CCD detectors cover two detection areas one for asteroseismology and the other for exoplanets detection. To avoid the saturation risk the seismology area is just in front of focal plane; in the exoplanet area a low power prism disperses the images to get color information about each observed star. This paper presents the procedure used to deduce the polychromatic PSFs for both the seismology and the exoplanets detection areas depending on position and star color indexes. The use of standard optical packages, the expected inaccuracies and performances are discussed.
The COROT small satellite project is a space mission dedicated to stellar seismology and search for telluric extra-solar planets. For the two programs a very high photometric precision is needed. The COROT seismology program will measure periodic variations with amplitude of 2.10-6 of the photon flux emitted by bright stars. COROT will also be able to detect the presence of exoplanets when they pass between the satellite and their parent star. Modifying both the integration time and the focus conditions, it allows to detect photons flux variations about 7.10-4 in one hour integration, compatible with an occultation detection on a very large number of stars (magnitude between 12 and 15.5). Between 10 and 40 telluric planets in the "habitable zone" and several hundreds of hot Jupiters should be detected depending on hypotheses about planets existence. To reach the required performances a stringent instrument stability is necessary. The satellite Preliminary Design Review will be held in November 2002 while the instrument is already in development phase for a delivery of the flight model in 2004. The launch is scheduled late 2005, by the first SOYUZ launcher to fly from the Guyana Space Center. The project activities are currently focused on the instrument and system engineering. Straylight rejection, pointing, thermal stability are the main critical points of the mission, on a LEO at 826 kms, for which cost-effective compromises have been found to 1mit their effects. This paper recalls the scientific program s, the main characteristics of the mission, describes the impact of the three main perturbators on the photometric precision and the technical solutions which reduce their contribution at an acceptable level.
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