Aschbacher and Nelson
ESA Director General Josef Aschbacher and NASA Administrator Bill Nelson talk about agreements signed June 15 to cooperate on Earth science and a lunar mission. Credit: ESA TV

PASADENA, Calif. — NASA and the European Space Agency announced agreements to cooperate on Earth science and a lunar mission June 15, but agency leaders said they’re still discussing more substantial cooperation on the Artemis program and Mars exploration.

After a meeting of the ESA Council in Noordwijk, Netherlands, NASA and ESA announced two new cooperative agreements. One, called the Framework Agreement for a Strategic Partnership in Earth System Science, outlines cooperation between the agencies on topics that include continuity of measurements and exchange of data. It builds upon a joint statement of intent the agencies signed in July 2021.

The other agreement is a memorandum of understanding regarding Lunar Pathfinder, a commercial lunar communications spacecraft being developed by Surrey Satellite Technology Ltd. with ESA as an anchor customer. It is slated to be ready for launch in late 2024 or early 2025. NASA will arrange for the launch of Lunar Pathfinder through its Commercial Lunar Payload Services program and gain access to communications services from the spacecraft. ESA and NASA will also collaborate on a navigation experiment using the spacecraft.

NASA Administrator Bill Nelson signed the agreements with his ESA counterpart, Director General Josef Aschbacher, at the ESA Council meeting. The agencies said it was the first time that a NASA administrator attended a meeting of the council, the governing body of ESA.

At a media briefing after the council meeting, Aschbacher and Nelson talked more about further cooperation between the agencies, such as roles NASA could play to assist ESA respond to impacts from sanctions stemming from Russia’s invasion of Ukraine. That includes the ExoMars rover mission, which was set to launch in September but is now postponed indefinitely after ESA severed cooperation with Roscosmos.

“Since the 24th of February, we have to say that this partnership intensified,” Aschbacher said of ESA’s relationship with NASA. “In space, the hand that was reached out by NASA to us was very welcome and very much appreciated.”

He said, though, that ESA is still evaluating options for continuing ExoMars, including those that involve NASA assistance. Aschbacher and other ESA officials have said they may seek from NASA new descent engines for the ExoMars lander, radioisotope heating units to keep the rover warm at night and perhaps a launch of the mission.

Aschbacher said NASA “offered help to conduct studies” for ExoMars, including a “very strong” letter of support from Nelson, but that ESA had yet to decide how to proceed with the mission. He said there are no plans to combine ExoMars with the Mars Sample Return campaign by NASA and ESA to return to Earth samples of the planet cached by the Perseverance rover.

“There are still a lot of intense discussions ongoing,” he said. “It’s going the right way and I’m very confident that we’ll find a good partnership on ExoMars. Of course, the final decision on our side is with our member states.”

“That is being discussed and is under consideration,” Nelson said about a NASA role on ExoMars. “That’s what we’re prepared to say today. We really want to help ESA given the circumstances.”

Another issue is cooperation between ESA and NASA on the Artemis initiative of human lunar exploration. ESA is contributing elements such as the service module for the Orion spacecraft and, with the Japanese space agency JAXA, modules for the lunar Gateway.

Such contributions come with the expectation that European astronauts will be assigned to Artemis missions, including landing on the moon. No ESA astronauts have been announced yet for Artemis missions.

Nelson said there is no firm timetable for selecting ESA astronauts to Artemis missions but that an ESA astronaut would be included on an Artemis landing some time after Artemis 3, currently scheduled for 2025. “What the composition of the crews are after that is all to be worked out and negotiated,” he said. “We will look forward to having an ESA astronaut with us on the moon at a future time.”

NASA Deputy Administrator Pam Melroy, who also attended the meeting, suggested an ESA astronaut could be assigned to Artemis 4, a mission currently planned not to land on the moon but to install European and Japanese components for the lunar Gateway. “We are absolutely intending that an ESA astronaut will support those missions to Gateway,” she said.

“This is all in the hands of NASA,” Aschbacher said of getting an ESA astronaut to the lunar surface. “Certainly, I would hope that it would be before the end of this decade, but this is my wish, which is well known to Bill.”

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...