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

WASHINGTON — The European Space Agency has officially ended cooperation with Russia on the ExoMars mission, prompting a Russian threat to halt use of a European robotic arm on the International Space Station.

ESA Director General Josef Aschbacher announced July 12 that the ESA Council formally decided to terminate cooperation on ExoMars, where Russia would have launched a European rover called Rosalind Franklin to the surface of Mars. That cooperation has been on hold since March.

While ESA has previously only suspended cooperation, it appeared highly unlikely that work with Russia would ever resume. Aschbacher said that the decision came because “the circumstances which led to the suspension of the cooperation with Roscosmos – the war in Ukraine and the resulting sanctions – continue to prevail.”

Since ESA’s decision to suspend work with Russia on ExoMars, it has been examining how to replace Russia’s contributions. That included not just the Proton launch of the spacecraft but also the Kazachok landing platform and some instruments and radioisotope heating units on the rover. Options include cooperation with NASA as well as entirely European alternatives.

Aschbacher said that ESA would provide “new insights on the way forward with other partners” at a July 20 media briefing, with details to follow. An ESA media advisory July 13, outlining its presence at the upcoming Farnborough International Airshow, said there would be a July 20 briefing in London “on the future of Mars exploration” with ESA, NASA and the U.K. Space Agency participating.

While ESA’s decision to formally end cooperation with Russia on ExoMars was not surprising, it prompted a sharp reaction from Dmitry Rogozin, head of Roscosmos. In a post on the social media network Telegram shortly after the ESA announcement, Rogozin accused Aschbacher of “sabotaging” the joint ExoMars mission. He said Roscosmos would seek the return of the Kazachok platform, which was in Europe for launch preparations at the time ESA suspended cooperation on the mission.

Rogozin also said he commanded the Russian cosmonauts on the station to no longer use a European robotic arm there. That arm is part of the Nauka module launched a year ago and still being commissioned.

It was not immediately clear if that command would be carried out and, if so, what effect it would have on ISS operations. It was also unclear if that would postpone a scheduled July 21 spacewalk from the Russian segment of the station by Roscosmos cosmonaut Oleg Artemyev and ESA astronaut Samantha Cristoforetti. A major purpose of that spacewalk is to work on that robotic arm.

ISS relations between Russia and the Western partners have seen increasing strain, particularly after Roscosmos published photos July 4 of Russian cosmonauts holding flags of two regions of Ukraine occupied by Russian forces. NASA, in a July 7 statement, strongly criticized Russia for that photo op, a sentiment shared by ESA’s Aschbacher.

“There is no place on the International Space Station for politics,” NASA Administrator Bill Nelson told reporters after an event July 12 at the Goddard Space Flight Center to mark the release of observations from the James Webb Space Telescope.

However, he reiterated that a “very professional relationship” continues among the ISS crew as well as between mission control centers in Houston and Moscow, and believed all the partners, including Russia, would remain involved through the end of the decade. “This is an international science, technology and research endeavor that will continue.”

Nelson added that negotiations continue between NASA and Roscosmos on a seat barter agreement to allow Russian cosmonauts to fly on commercial crew vehicles in exchange for American astronaut flying on Soyuz spacecraft. NASA ISS managers said in the spring that a deal needed to be concluded by June to enable crew swaps for missions launching in September.

“The drop-dead date has not passed,” he said, but didn’t indicate when a deal needed to be concluded.

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...