WASHINGTON — Leaders of several national space agencies endorsed continued cooperation in space exploration, including missions to the moon, and said that effort should not come into conflict with separate work to address climate change.

Speaking at a panel of agency leaders during the 70th International Astronautical Congress here Oct. 21, NASA Administrator Jim Bridenstine said he expected more countries to join the agency’s return to the moon after commitments made earlier this year by Canada and last week by Japan.

“We need international partners. We can all do more when we work together,” he said during a session that included representatives from Canada, Europe, India, Japan and Russia.

The European Space Agency is likely the next agency to make a decision on cooperation, at its next ministerial meeting in Spain in late November. Those decisions, ESA Director General Jan Woerner said, will include producing additional service modules for the Orion spacecraft and providing modules for the lunar Gateway.

Russia is also weighing its role in NASA’s lunar programs, including the lunar Gateway. “We are planning to participate in the Gateway, but we don’t have a final decision how,” said Sergey Krikalev, executive director for piloted spaceflight at Roscosmos. “International cooperation is important.”

Krikalev said at a later press conference that Russia’s contribution to the Gateway will probably involve some kind of transportation system, such as the crewed spacecraft Roscosmos has been developing for several years, providing an alternative to NASA’s Orion to get crews to the Gateway. “We think the redundant transportation system and one of the modules for Gateway would be our participation in the program.”

Bridenstine and others, though, didn’t specify when those general commitments would be turned into firm, binding agreements of some kind. Part of that uncertainty, he said, depends on the efforts in various countries to win approval, and funding, for their contributions.

“It’s kind of like a jigsaw puzzle,” he said. “It takes some time to put it together, but all the pieces will come together. We just have to continue to work on it.”

Those agencies expect that cooperation on the lunar Gateway and other aspects of lunar exploration will be governed by the same intergovernmental agreement, or IGA, currently used by the partners on the International Space Station. That IGA could be extended in some way, such as through memoranda of understanding among the partners, to encompass lunar missions.

Woerner noted it took eight years to negotiate the original IGA for the space station. “I don’t want to wait eight years,” he said. “We should try whenever we can to use the IGA for the ISS.”

Bridenstine agreed. “Extending the IGA is the quickest way to make it happen,” he said. “As long as well agree, we can keep moving forward.”

The wide-ranging panel discussion also brought up whether space exploration, including human missions to the moon, could be justified given growing concerns about climate change. One question posed to the panel asked how they might explain why government should fund space exploration to young climate change activists like Greta Thunberg.

Woerner argued that space was essential to the study of climate change, noting that the greenhouse effect was traced back to studies of Venus, where a runaway greenhouse effect caused extreme heating of its atmosphere. “This shows already that climate change has a direct link to exploration,” he said. “Space is helping Greta.”

Bridenstine notes that many space technologies can also be applied on Earth to reduce greenhouse gas emissions, such as batteries and solar panels. “If we are worried about greenhouse gas emissions, how can you not explore space? That’s the question.”