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Japan’s heavy investment in space capabilities, coupled with the importance of space in supporting U.S. power projection in the region, has contributed to space becoming a strategic pillar of the U.S.-Japan alliance in recent years.
The importance of the bilateral space partnership was highlighted recently in a joint statement from the February 2025 meeting of President Trump and Japanese Prime Minister Shigeru Ishiba, which noted the intent to continue the “strong partnership in civil space and on aeronautics, science, and human exploration, including on the upcoming Crew-10 mission to the International Space Station that includes U.S. and Japanese astronauts as well as lunar surface exploration on future Artemis missions.” Left unsaid in that statement is the vital allied partnership on national security and commercial space as well.
As policymakers on both sides of the Pacific chart a course for the bilateral space alliance for the next four years, there are at least three areas they should seek to address for future deliverables: national security space architectures, global leadership, and promoting investment.
Stronger National Security Space Architectures
While Japan is a relative newcomer to the military use of space, Japan has been making up for lost time via a base defense budget that will soon hit 2 percent of GDP (exceeding many NATO members), as well as supplementary investments into dual-use space technology. Such funding has spurred a number of Japanese Ministry of Defense (JMOD) programs, including but not limited to space-based intelligence, surveillance, and reconnaissance (ISR), and missile warning and tracking.
Encouraging the acceleration of Japan’s development of space security capabilities supports the common U.S. and Japanese objective of having Japan shoulder more of the burden for its own defense. However, in order to do so, new capabilities need to contribute hard power to the alliance’s ability to deter adversaries and, should deterrence fail, ensure the alliance prevails in conflict. This implies a number of requirements for JMOD space capabilities, including that they are interoperable with those of the United States, that they will be resilient in a contested environment (including having information security standards hardened for conflict), that they can support real-time operations, and that they can be acquired quickly amidst a worsening security environment and fiscal constraints.
Regarding space-based ISR, JMOD is investing significantly in acquiring a near-term capability. However, to date, this effort has been conducted mostly in isolation from the United States and lacks clear operational requirements. Moving forward, bilateral engagement in this area must be enhanced so that new Japanese space ISR capabilities are truly additive to the combined allied architecture, including the fielding of additional satellites.
Regarding missile warning and tracking, during the visit of former Prime Minister Kishida to the United States in 2024, the nations announced, “bilateral collaboration on a Low Earth Orbit detection and tracking constellation for missiles such as hypersonic glide vehicles, including potential collaboration with U.S. industry.”
Since that time, public signs of implementation have been scarce. However, the project’s importance has only grown, as such missile detection and tracking can also contribute to the new administration’s “Golden Dome” missile defense initiative. Both sides should seek to make a near-term announcement concerning the implementation way ahead for Japan’s missile warning project, including the bilateral industrial partnership. This requires getting specific implementation actions by JMOD, the U.S. Department of Defense, and industry.
Global Leadership in Exploration
The U.S. space community is currently engrossed in another round of debate over the destination of the human exploration program, specifically whether to keep the current Moon and then Mars approach (perhaps with a streamlined architecture), or to go back to an Obama administration–style “Mars only” approach.
As such a debate plays out, what should not be in question is that Japan will be key to making such exploration efforts sustainable over the long term. In April 2024, Japan made the largest allied investment ever into the U.S. lunar surface architecture through its commitment to a pressurized lunar rover. Consistent with such a level of investment, the United States and Japan committed to a Japanese national being the first international Artemis astronaut on the Moon. As soon as there is alignment between the U.S. executive and legislative branches regarding possible changes to the Artemis program, the United States and Japan should identify which mission the first Japanese astronaut will fly on and make that announcement a deliverable for a future leader-level meeting.
Regardless of when the United States decides to go to Mars, it will need a sustainable long-term architecture there as well. For example, the United States and Japan could conduct a study of the potential contribution of a variant of the Japanese pressurized rover to the Martian architecture.
Strengthening Space Investment
Promoting investment has taken center stage during the Trump administration, and during Prime Minister Ishiba’s visit, he pledged to boost Japan’s overall investment in the United States to $1 trillion.
Space will likely be a part of meeting such a goal. Indeed, consistent with its status as the top source of foreign direct investment into the United States, Japan has already been contributing to a range of U.S. space companies and initiatives, including commercial space stations to succeed in the 2030 retirement of the International Space Station.
Moving forward, promoting investment in the bilateral space partnership will assume even greater importance, and investment and partnership in cutting-edge space startups in both countries can enhance and expand the combined allied industrial base to the strategic benefit of both nations.
The Department of Commerce should actively facilitate such efforts, including by convening an investor summit focused on the U.S.-Japan space investment partnership. Japan, for its part, should also clarify the posture of the JAXA Space Strategy Fund vis-à-vis partnerships with U.S. entities, so that the fund’s investments into Japanese companies can act as a catalyst for U.S. investors as well.
Conclusion
In closing, space cooperation can contribute to helping both nations achieve a range of their national goals, including security, economic growth and innovation, and scientific research. Some key bilateral areas for supporting such goals over the next four years could include strengthening allied national security architectures, leading the world in exploration, and strengthening space investment.
Sean Wilson is a senior associate (non-resident) with the Aerospace Security Project at the Center for Strategic and International Studies in Washington, D.C. He is also the founder and CEO of the Mirai Group and the former director of international space policy at the White House.
The opinions and characterizations in this piece are those of the author and do not necessarily represent those of the U.S. government.
