Arianespace launches ESA’s CHEOPS satellite to study exoplanets

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HELSINKI — A Soyuz rocket successfully launched an Italian Earth observation satellite Dec. 18, with the European CHEOPS mission to analyze exoplanets and three small auxiliary payloads also along for the ride.

The four-stage Russian Soyuz lifted off at 3:54 Eastern, Wednesday, marking the 23rd Soyuz mission for Arianespace from the Guiana Space Center in French Guiana. A previous attempt one day earlier was scrubbed due to a launcher software issue.

The primary payload in terms of mass was the first of the second generation of Cosmo-SkyMed dual-use radar reconnaissance satellites for the Italian government. The 2.2-metric-ton satellite, manufactured by Thales Alenia Space for the Italian Space Agency, separated from the Fregat upper stage 23 minutes after launch.

The 273-kilogram wet mass CHaracterising ExOPlanet Satellite (CHEOPS) entered its intended near-polar dusk-dawn Sun-synchronous orbit following separation 2 hours 24 minutes after launch.

CHEOPS is designed to follow up on already detected exoplanets. It will precisely measure the diameters of known exoplanets using transit photometry — measuring the minuscule dips in light emission from a star as an orbiting planet passes in front of it. 

It will focus on ascertaining the mass-radius relation of exoplanets between 1-20 Earth masses and identifying planets with significant atmospheres. It will also provide insights into planet migration paths and identify planets that are prime targets for future habitability studies across 3.5 years of science operations.

Airbus is prime contractor for the mission, with the telescope provided by the University of Bern in collaboration with the University of Geneva.

Three CubeSats were also aboard as auxiliary payloads. EyeSat, a 3U CubeSat (5 kg) student satellite, and ANGELS, a 30-kilogram technology miniaturization test satellite, were both launched for CNES of France. ESA’s OPS-SAT will be testing and validating new techniques in mission control and on-board satellite systems. 

The launch was the ninth and final mission for Arianespace in 2019 and the third Soyuz launch from Kourou this year. This number includes a Vega launch failure in July, resulting in the loss of the UAE’s Falcon Eye-1 optical imaging satellite.