According to the Bloomberg article Japan Astronauts to Soon Join U.S. in Trip to Mars, Trump Says:
The U.S. and Japan will “dramatically expand” their cooperation in outer space, with missions to Mars and the moon coming “very soon,” President Donald Trump said, as his administration challenges China for dominance beyond Earth’s orbit.
“Japan will join our mission to send U.S. astronauts to space,” Trump said during a joint news conference with Prime Minister Shinzo Abe in Tokyo on Monday. “We’ll be going to the moon, we’ll be going to Mars very, very soon. It’s very exciting. From a military standpoint, there is nothing more important right now than space.”
Since the acceleration of crewed space exploration is high on the current US president's administration's priority list as indicated by it's sudden goal to put boots on the Moon in five years, the president's statements about Japan's involvement during his visit to Japan involving one-on-one discussions with Japan's president must be based on some solid and tangible plans.
From here:
"The prime minister and I talked lot today about trade and military and various other things. I think we had a very productive day," Trump said at the start of the dinner after being handed his first course on a long wooden paddle.
Question: What is the US president talking about?
The last bit about the military standpoint is particularly intriguing.