PARIS — The French space agency, CNES, on May 2 said it had signed with NASA a formal work-share agreement on the Surface Water and Ocean Topography (SWOT) altimetry satellite to be launched in 2020.

The agreement, signed by CNES President Jean-Yves Le Gall and NASA Administrator Charles Bolden, calls for CNES to provide the satellite’s platform, a radio-frequency unit for the U.S.-built Ka-band Radar Interferometer, a Doppler positioning instrument and an altimeter. In addition, France will provide the SWOT mission’s satellite command-and-control center, a network of data-reception stations and the French ground segment.

Le Gall said in a May 2 interview that the total French contribution is valued at about 174 million euros, or $238 million, and is being partly financed through the French government’s Investing in the Future bond issue.

NASA will provide the satellite’s launch vehicle, the U.S. ground segment and the satellite’s payload — the radar interferometer, dubbed KaRIN; a radiometer and GPS receiver.

In an April report, the U.S. Government Accountability Office  said the NASA share of the SWOT budget is estimated at around $700 million. GAO also said the program was at risk of having to replace or reduce the capabilities of the French nadir altimeter because of possible cost overruns.

Le Gall said this is not currently considered an issue given that the mission is still six years from launch.

SWOT will be the latest in what in 2020 will be a 30-year line of U.S.-French altimetry missions, starting with Topex-Poseidon and then the Jason series of ocean-altimetry satellites.

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