Japan to Develop Hypersonic Missile Propulsion Under Joint Project Agreement Inked With US

Japanese technology will be used for the rocket motors and propulsion devices of hypersonic missiles to be developed under the Glide Phase Interceptor Cooperative Development Project Arrangement signed by the U.S. Department of Defense and Japan’s Ministry of Defense.

According to the Pentagon, the U.S. Missile Defense Agency is spearheading the DOD’s GPI development, which is aimed at providing missile defense capability at the glide phase of hypersonic flight. The agreement was signed under the U.S.-Japan bilateral Memorandum of Understanding for Research, Development, Test and Evaluation Projects, the DOD said Wednesday.

The department pointed out that the joint GPI development will boost regional defensive capability, as well as enhance the long-established missile defense collaboration between the United States and Japan.   

President Joe Biden and Japanese Prime Minister Fumio Kishida initially agreed on the GPI cooperation during a trilateral summit with South Korean President Yoon Suk-yeol in August.

Vice Adm. Jon Hill, MDA director and a speaker at a past Potomac Officers Club event, disclosed in March 2023 that a GPI risk review has been completed and the agency is seeking hardware development approval from the Joint Requirements Oversight Council. In June 2022, the MDA awarded a $41 million contract to Raytheon Missiles & Defense to finalize GPI systems requirements and support accelerated development schedules.