The SWOT spacecraft in a Thales Alenia Space factory in France, being prepared for shipment to the U.S. A lack of Antonov aircraft meant NASA had to ask the U.S. Air Force for assistance transporting SWOT to Vandenberg Space Force Base in California. Credit: Thales Alenia Space

WASHINGTON — A joint U.S.-French Earth science mission is ready to be delivered to California for a launch now scheduled for early December, a slight delay caused in part because of transportation issues.

Thales Alenia Space, the prime contractor for the Surface Water and Ocean Topography (SWOT) spacecraft, said Sept. 6 it is making final preparations to ship the two-ton spacecraft from its factory in Cannes, France, to Vandenberg Space Force Base in California. There, it will be integrated with a SpaceX Falcon 9 for a launch no earlier than Dec. 5.

SWOT, a joint mission of NASA and the French space agency CNES, with participation from the Canadian Space Agency and U.K. Space Agency, will carry out observations for oceanography and hydrology using a synthetic aperture radar, altimeter and other instruments. Scientists plan to use SWOT to conduct a global survey of the Earth’s water, including measuring changes in lakes and rivers as well as ocean currents.

Getting the spacecraft from France, where the NASA-supplied science payload was installed on the Thales-built spacecraft and then tested, to the United States, turned into more than a challenge than once expected.

“We had a slight issue with the transport of it,” said Kathleen Boggs, acting associate director for flight programs in NASA’s Earth science division, at an Aug. 2 advisory committee meeting. “It was supposed to come back on a Ukrainian Antonov aircraft that was provided by CNES.”

Those aircraft, though, have largely been grounded because of sanctions and other issues linked to Russia’s invasion of Ukraine. Those aircraft had been frequently used before the invasion to transport large satellites that do not fit on other cargo aircraft, and with the planes unavailable, satellite manufacturers have limited options for transporting their spacecraft to launch sites by air.

Boggs said at the meeting that NASA was “pretty close” to an agreement with the U.S. Air Force to transport the spacecraft. In its Sept. 6 release, Thales Alenia said SWOT will be transported to California in early October on a U.S. Air Force C-5 cargo plane “deployed specially” for SWOT.

Using the Air Force to transport the plane, she added, was preferable from a schedule standpoint to using a ship. “If we have to use transport by sea, it could cost us some time and some money, so we’re pushing really hard for the Air Force solution.”

Arranging that alternative transport did contribute to a schedule slip for the launch of SWOT. NASA announced Aug. 25 that the launch, which had previously been scheduled for November, was now planned for Dec. 5. The agency said the delay “was needed in order to complete all the necessary tasks in the lead-up to launch, including transporting the satellite from Cannes, France, to Vandenberg Space Force Base in California.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...