PARIS — The European Space Agency on May 11 contracted with Airbus Defence and Space to build an ocean topography satellite to follow on from today’s U.S.-European Jason spacecraft as part of a mission that presumes future financing from Europe’s Eumetsat meteorological satellite agency.

Under the contract, valued at 177 million euros ($192 million), Airbus will build the 1,400-kilogram Jason-CS/Sentinel-6A satellite in time for a launch in 2020, if needed.

The contract includes a fixed-price option for an identical second satellite that would be launched around 2025 — again, as needed depending on the health of the preceding mission. As a recurrent-model satellite, it is budgeted at between 40 percent and 60 percent of the cost of the first model.

Darmstadt, Germany-based Eumetsat is contributing only a small sum to the satellite, but is expected to finance a much larger share of the second unit once the agency’s ruling council gives formal approval of the program. That is expected to occur in June.

As an optional Eumetsat program — most of the agency’s missions are financed by mandatory contributions from its 30 member governments — Jason-CS/Sentinel-6 does not require 100 percent endorsement by Eumetsat members. Individual nations contribute as they see fit, and programs can move forward if at least 90 percent of the total budget is subscribed.

Volker Liebig
Volker Liebig, ESA’s director of Earth observation. Credit: ESA/P. Sebirot
Volker Liebig, ESA’s director of Earth observation. Credit: ESA/P. Sebirot

The Jason series started with the U.S.-French Topex-Poseidon satellite in the early 1990s before the Jason-1 and Jason-2 satellites were launched. As more and more government entities — including the U.S. and French navies — found uses for the satellites’ precise wave-height measurements, Eumetsat and its U.S. counterpart, the National Oceanic and Atmospheric Administration, joined the program.

The relations between NOAA and NASA with respect to the Jason series are changing, with NASA taking charge of financing the U.S. contributions, including the launch.

Jason-3 is scheduled for launch in late July aboard a SpaceX Falcon 9 rocket from Vandenberg Air Force Base, California. If, like its predecessors, it is able to function well beyond its five-year design life, the launch of Jason-CS/Sentinel-6A may wait until 2021.

“We would like to be ready with the launch five years after Jason-3,” said Volker Liebig, ESA’s director of Earth observation. “But if Jason-3 lasts as long as its predecessors, we might be able to wait until 2021.”

In a May 12 interview, Liebig said the ESA-Airbus contract includes an option for a second satellite that assumes a Eumetsat go-ahead in June. If there is a problem with the Eumetsat financing — which is not now expected — then ESA and Airbus would enter negotiations to determine how to proceed.

In addition to the launch of both the Jason-CS/Sentinel-6A and -6B satellites, NASA is contributing a radiometer and a GPS Precise Orbit Determination receiver.

The European Commission, which is the executive arm of the 28-nation European Union, is contributing about 91 million euros to the mission, which has been included in the commission’s broad Copernicus environment-monitoring program of Sentinel satellites with multiple sensors.

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