PARIS — Thales Alenia Space will build the SWOT ocean-altimetry satellite as part of a U.S.-French collaboration and Airbus Defence and Space will build the Merlin methane-detecting satellite as part of a joint Franco-German program under contracts expected to be signed in the coming weeks, the French space agency, CNES, said Dec. 5.

The 2,000-kilogram SWOT, or Surface Water Ocean Topography, satellite is a continuation of a long-standing partnership between NASA and CNES in ocean altimetry that began in the early 1990s. SWOT is tentatively scheduled for launch in 2020.

Merlin, or Methane Remote Sensing Lidar Mission, is being financed jointly by the French and German governments — CNES for France, the German Aerospace Center, DLR, for Germany — to fill one of the gaps in current satellite detection of gases contributing to the Earth’s warming. Originally scheduled for development in time for a 2014 launch, a new launch date has not been announced.

Peter B. de Selding was the Paris bureau chief for SpaceNews.