Japan and US commit to hypersonic weapon co-development

Japan and the United States signed an agreement on 15 May to jointly develop the Glide Phase Interceptor (GPI), a next-generation missile defence system capable of defeating hypersonic missiles that are deployed by China and Russia and being developed by North Korea.

The GPI Cooperative Development Project Arrangement was initially agreed between Japan’s Prime Minister Fumio Kishida and US President Joe Biden in August 2023, although the latest agreement represents a key milestone that determines the allocation of responsibility and decision-making process.

Japanese officials stated that the government intends to select its domestic industry contractors and commence development of components for key subsystems such as the propulsion motor by March 2025. The complete GPI system is expected to be fielded by the mid-2030s.

“In recent years, around Japan, missile-related technologies such as hypersonic weapons have improved dramatically,” the Japan Ministry of Defense (JMOD) said in a statement. “Strengthening interception capabilities against them is an urgent issue.”

JMOD noted that the government has budgeted approximately US$490 million for initial development and testing of the interceptor, which includes the cost of component manufacture for the eventual winner of the GPI programme. Two US companies, Northrop Grumman and RTX company Raytheon Technologies, are competing to lead the effort under the auspices of the US Missile Defense Agency. (MDA) One will be chosen for the project.

According to the MDA, the GPI programme will likely exceed US$3 billion. Japan is expected to fund more than US$1 billion of that figure.

“By pursuing an agreement on GPI development, the US and Japan will strengthen regional deterrence while enhancing longstanding missile defense cooperation between the two countries,” said the US Department of Defense (DoD).

Japan and the United States have previously co-developed the SM-3 Block IIA missile, which is being manufactured by Raytheon Technologies, under a similar arrangement.

by Jr Ng