The ExoMars Rosalind Franklin rover.
ESA’s ExoMars rover will join an orbiter launched in 2016 on a mission to search for evidence of past life on Mars. Credit: ESA

Updated 2:45 p.m. Eastern with comments with ESA press conference.

TITUSVILLE, Fla. — The European Space Agency has formally halted plans to launch its ExoMars mission on a Russian rocket in September in response to Russia’s invasion of Ukraine.

The ESA Council, at the conclusion of its latest meeting March 17, unanimously voted to suspend cooperation with Russia on the ExoMars mission, citing “the present impossibility of carrying out the ongoing cooperation with Roscosmos,” according to an ESA statement.

“We deeply deplore the human casualties and tragic consequences of the aggression towards Ukraine,” ESA said in the statement. “While recognizing the impact on scientific exploration of space, ESA is fully aligned with the sanctions imposed on Russia by its Member States.”

“The decision was made that this launch cannot happen given the current circumstances,” ESA Director-General Josef Aschbacher said at a briefing March 17, citing the sanctions imposed by European nations on Russia. “This makes it practically impossible but also politically impossible to have a launch in September.

The announcement was all but inevitable after ESA announced Feb. 28 that it was “very unlikely” it would go forward with the late September launch from the Baikonur Cosmodrome in Kazakhstan because of the sanctions imposed on Russia in response to Russia’s invasion of Ukraine.

“It’s a disappointment for the people involved in the project,” said David Parker, head of human and robotic exploration at ESA, noting the years they put into the mission. “It was an agonizing decision for the council to make.”

A new plan for ExoMars would involve more than replacing the Proton rocket. Russia also built a landing platform called Kazachok that would have to be replaced. The rover itself includes Russian instruments and radioisotope heating units supplied by Russia.

The council instructed Aschbacher to start a “fast-track industrial study” to look at alternatives for launching the mission, which will place the European-built Rosalind Franklin rover on Mars. “What we really need to do is to look into these options,” he said. “The options in terms of Europe alone or Europe with other partners.”

One option, Aschbacher said, was renewed cooperation with NASA. ESA originally planned to cooperate with NASA on the ExoMars program, but turned to Russia a decade ago when NASA pulled out of the program. “Cooperation with NASA is an option we’ll look into,” he said. “NASA has expressed its very strong willingness to support us.”

If the relationship with Roscosmos was restored, Parker said, a 2024 might be feasible. “A more radical reconfiguration would lead to launch in 2026, when there are two launch opportunities, or 2028.”

“It will not be before 2026, realistically,” Aschbacher said of the revised launch date. “Even that is very challenging.”

“I have a lot of sympathy for those people who have been working on this project for decades,” Ashchbacher said. “I can understand the frustration of people on the engineering side, the science side, the community side.”

“But let me say, even if we launch later,” he added, “the science that will be produced by this rover is still outstanding and best in the world.”

The statement also addressed Russia’s Feb. 26 decision to halt Soyuz launches from French Guiana and withdraw its personnel there in response to the European sanctions. That decision puts five European missions in limbo: two launches of Galileo navigation satellites, ESA’s Euclid space observatory and EarthCARE Earth science satellites, and a French reconnaissance satellite.

The ESA statement said that Aschbacher “has initiated an assessment on potential alternative launch services for these missions, which will include a review of the Ariane 6 first exploitation flights.” The first Ariane 6 launch, scheduled for no earlier than the second half of this year, is currently set to carry an assortment of small private and educational spacecraft and instruments, along with a mass simulator.

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...