CoRoT (Convection, Rotation and planetary Transits) is the first space mission dedicated to exoplanetary research and designed for this purpose. The spacecraft is equipped with a 27 cm-diameter afocal telescope and a 4-CCD wide-field camera, is built around the PROTEUS spacecraft bus, and operates in a low-Earth orbit (LEO) of ~900 km (polar). Launched in December 2006 the mission had a nominal lifetime of 2.5 years, subsequently extended until 31 March 2013, during which time it will study stellar interiors and search for exoplanets. The project is led by CNES, with contributions from ESA, Austria, Belgium, Germany, Spain and Brazil.
CoRoT, belongs to the PROTEUS program and has two scientific objectives:
- Detection and the study of star vibrations (stellar seismology)
Search for extrasolar planets and more particularly the telluric planets
CoRoT is an acronym for: Convection Rotation and planetary Transits.
|Mass||630 kg at launch|
|Pointing accuracy||0.5 arcsec|
|Mass storage||2 Gbit|
|Delta V||90 ms-1|
The detectors are 4 CCD's 2048 x 2048 wide, (EEV, 13.5-μm thinned, back illuminated), working in the visible in the MPP mode. They are installed in the focal box, which is at a temperature of -40 °C with a variation that is less than 0.05 °C per hour.
For the seismology mission, the image spot for a star is spread out on about 400 pixels, with an exposure time of 1 second.
A prism, allowing to get a colour image of the stars, is installed before the exoplanet field. It will enable to distinguish between stellar activities and a planetary transit, for the brightest stars.
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 1.2 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.
CoRoT is in a circular polar orbit around the Earth at an altitude of 896 km. The telescope is pointed to observe within a cone of 10° from the perpendicular to the orbit. This ensures there is no Earth occultations to hinder the observations.
The Operational Ground Segment is in charge of the satellite housekeeping, the mission programming, the telemetry reception from the satellite, as well as data and services delivery to the scientific users (PIs and Co-Is).
It is composed of the Mission Center (located in Toulouse), the Control Center (located in Toulouse), the communication network and ground stations located in Kiruna (S), Aussaguel (F) Hartebeesthoek (South Africa), Kourou (French Guyana), with mission specific ground stations in Alcantara (Brazil) and Vienna (A).
The CoRoT Mission Center and the CoRoT Data Center form the User Ground Segment.