Might American and Japanese astronauts together stage the first moon landing in more than fifty years? Secretary of State Blinken and the Japanese foreign minister, Yoshimasa Hayashi, raised just that possibility as they signed an agreement for “Japan-U.S. Space Cooperation” at NASA headquarters in Washington last week.

“Japan and the U.S. are planning development of lunar exploration vehicles, lunar activities by Japanese and American astronauts,”said Mr. Hayashi.

The two will be collaborating under the Artemis program that calls for NASA, along with the Japan Aerospace Exploration Agency and the European Space Agency, to revive exploration of the moon. Incredibly, the last time anyone reached the moon was in December 1972 when Apollo 17 deposited two astronauts  long enough to sample the surface and plant an American flag.

Clearly the Japanese see moon exploration as the most compelling aspect of a deal that calls for cooperation on a wide range of space projects, some for defense against plans by Japan’s primary foes, Communist China and North Korea, who are threatening Japan with long-range missiles powered by systems for putting satellites into orbit.

Mr. Hayashi preferred to suggest space cooperation with America would “benefit the future of all mankind” and predicted “more activities by both of our countries’ experts working on space.”

Japan’s eagerness was expected to fire up American interest in venturing again to the moon.  “That’s one small step for man, one giant leap for mankind,” Neil Armstrong proclaimed as he and Buzz Aldrin felt the crunch of the moon’s rocky surface underfoot after the first moon landing on July 20, 1969.

Enthusiasm, though, waned after another five missions in which a dozen astronauts could claim to be “moon men.” The program was revived under President Trump after President Obama had canceled it.

Indeed, the agreement between Washington and Tokyo may be the most substantive dividend of the visit of Japan’s Prime Minister Kishida to Washington at which he and President Biden engaged in a rhetorical exchange of pledges for mutual defense. 

Mr. Kishida outlined Japan’s new defense strategy of vastly increasing its military budget for Tomahawk missiles, new planes — including drones — and space technology, but said nothing about increasing the size of Japan’s self-defense forces, now 250,000 troops  in all services. The sense was Japan remains reluctant to send forces overseas until or unless war breaks out, possibly on Taiwan, which China has vowed to recover.

At NASA headquarters, Mr. Kishida said space cooperation with Washington “has entered a new era with the Artemis project.” Excitement over reaching the moon was the dominant theme. “Many projects, including lunar activities, are already in the works by Japanese and U.S. astronauts,” he said.

Mr. Blinken injected the thrill of collaborating with Japan in space. The deal, he said,  would “strengthen our partnership in areas like research on space technology and transportation, robotic lunar surface missions, climate-related missions, and our shared ambition to see a Japanese astronaut on the lunar surface.”

How about going for Mars? Mr. Blinken predicted  “incredible discoveries, as we prepare to send a probe to Mars’s moons, explore the South pole of our Moon, and more.” The possibilities seem endless, as do the costs, which are carefully left unmentioned.