ESA Director General said ESA is continuing discussions with NASA about how NASA could help replace Russian elements of the ExoMars mission, while also considering European alternatives. Credit: Tom Kimmell Photography

COLORADO SPRINGS — The European Space Agency is continuing discussions with NASA on how the agencies can work together to revive ESA’s ExoMars mission after ending cooperation with Russia.

ESA announced March 17 it halted plans to launch the mission, featuring a European-built rover, in response to Russia’s invasion of Ukraine. Russia was to launch the mission on a Proton rocket and provide a landing platform and other components.

“It was not an easy decision,” Josef Aschbacher, director general of ESA, said during a panel of space agency leaders at the 37th Space Symposium April 6. Scientists and engineers had worked for years on the mission and the rover now is nearly complete. At the time of the decision to suspend work with Russia, it being prepared to ship to the Baikonur Cosmodrome in Kazakhstan.

He thanked NASA for contacting ESA and offering assistance on ExoMars, adding in a later interview that discussions between the agencies are continuing. “Our teams are working with the teams in NASA about the technical steps that need to be done,” he said.

The agencies are looking at options for replacing the Russian elements of ExoMars, such as the launch vehicle and landing platform. Other components that Russia was providing were radioisotope heating units to keep the rover warm at night, a technology commonly used by NASA but which for ESA is much less mature.

Another option ESA is pursuing is to replace Russian components with European ones. Aschbacher said studies are ongoing on technical and financial aspects of both strategies, which should be completed by June. “By July, I expect to have a decision from my member states,” he said, which would become part of the package for ESA’s ministerial meeting late this year.

ESA is also studying options for launching missions that were to fly on Soyuz rockets from French Guiana that were stranded by Russia’s decision in February to halt such launches. Those missions include two pairs of Galileo navigation satellites, two ESA science missions and a French reconnaissance satellite.

Aschbacher said ESA is study ways to launch those satellites using Ariane 6 and Vega C launch vehicles, both of which are scheduled to make their inaugural launches this year. That will depend in part on an ongoing assessment of ramping up Ariane 6 launches expected to be done in a month. At that point, he said ESA will be able to better determine how to launch those payloads.

“One option might be that we have to look, for a limited period of time, at backup launcher options,” he said, which would include non-European launch vehicles. “I would expect this would be a very limited period where we would need such solutions and then we can fully rely on Ariane 6.”

Aschbacher, like NASA officials, said that International Space Station operations remain unaffected by the Russian invasion of Ukraine, and that ESA was preparing proposals to extend its role on the ISS through 2030. “We’re working toward the normal continuation of the operations of the ISS.”

Aschbacher said on the panel that, shortly after Russia’s invasion of Ukraine, the Ukrainian government asked to join ESA. “This is a big decision and not something that can be done very quickly,” he said in the interview, with a years-long process that nations must follow to become full members. “This is not something that will happen tomorrow.”

He said ESA was considering ways it could assist Ukraine in the near term, such as providing satellite data to support damage assessments and agriculture. “I would expect significant financial support from the West in rebuilding Ukraine, and space can help with that.”

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...