On April 6 2017 it was officially announced, that Cheops satellite designed by Airbus Defence and Space for ESA will be delivered to orbit in 2019 by Arianespace.
Decision was made to favor of Arianespace and surely will strengthen position of the Company as leading launch service provider on European market. Contract will be officially signed within following weeks.
Cheops is acronym for Characterising Exoplanets Satellite - it is small satellite (with mass of 250 kg and dimensions of 1.5 m × 1.4 m × 1.5 m) designed with utilization of Astrobus-300 to operate on 650 - 800 km SSO orbit for 3.5 years. During its mission satellite will focus on searching for bright stars having possibly planets around them. After finding such planet Cheops will measure its diameter what will help in evaluating density of the planet (of course if previously mass of this planet was known). It will help in further studies on their structure or composition.
Cheops is simple spacecraft equipped only with few instruments - based on single CCD photometer operating in the visible light. Photometer weighs 58 kg and has focal length of F/9 with diameter of the lens of 320 mm and it operates on 400 -1100 mm wavelengths. Another device inside cargo compartment of the satellite will be small telescope installed on special bench to provide best possible stabilization what is necessary to provide most accurate measurements. Telescope is medium sized with 30 cm aperture. Satellite will be stabilized in 3 axis and powered by solar arrays installed on the fuselage. Cooling system necessary to keep scientific instruments away from heat generated by the Sun was placed in the fuselage - satellite will rotate around axis of the telescope to put radiator into shadow and low the temperature.
Satellite was created under the partnership between European Space Agency and Swiss Space Office. Total cost of the mission is estimated for €50 million.