PARIS — The French and Chinese space agencies on March 27 confirmed their joint venture in radar ocean-surface research, approving the final construction of a satellite carrying instruments from both nations to be launched in 2018.

The China-French Oceanic Satellite, CFOSat, will carry the French Surface Waves Investigation and Monitoring, or SWIM, instrument, a wave-scatterometer spectrometer that has been under development for several years at the French space agency, CNES.

The China National Space Administration, in addition to providing the CFOSat platform and a launch of the 700-kilogram satellite on a Chinese Long March rocket, will build the SCAT wind-measurement scatterometer.

CNES has long made a priority of ocean-surface studies. It has a longstanding cooperation with NASA on ocean altimetry through the Topex-Poseidon and Jason series of satellites and the future Surface Water Ocean Topography mission. CNES also has a joint effort with India on the Saral/AltiKa satellite, launched in early 2013.

CNES said it would provide X-band telemetry equipment, on the ground and on the satellite, in addition to the SWIM instrument. The agency said its total investment in CFOSat is about 150 million euros ($200 million), of which 40 million euros has already been spent on contracts with French industry.

The CNES-CNSA agreement to complete CFOSat was concluded during a French-Chinese summit in Paris March 27, and the two nations’ heads of state witnessed the signing.

Longer term, CNES and CNSA agreed to investigate a future joint venture in space-based astronomy with the Space Variable Objects Monitor to study gamma-ray bursts. The two agencies agreed to meet in June to work out details of the mission, which would be launched as early as 2020 on a Chinese Long March rocket.

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Peter B. de Selding was the Paris Bureau Chief for SpaceNews.