By Olawale Abaire, Warrior Editorial Fellow
In a recent development, Japan and the United States have signed an agreement to jointly develop interceptors capable of shooting down hypersonic missiles. This development is part of a plan reportedly costing over $3 billion and aims to address the increasing threat posed by hypersonic weapons in the region. The Glide Phase Interceptor (GPI) is a major part of the agreement.
The GPI co-development will build upon long-standing U.S.-Japan missile defense cooperation and strengthen the Alliance deterrence posture. The interceptors will be designed to fit into the U.S. Navy’s Aegis ballistic missile defense-equipped destroyers. The weapon will fire from the standard vertical launching system and be integrated with the modified Baseline 9 Aegis Weapon System that detects, tracks, controls, and engages hypersonic threats.
The U.S. Missile Defense Agency is leading the development of GPI for the Department of Defense, which will provide hypersonic missile defense capability during the glide-phase portion of hypersonic flight. As part of the agreement, Japan will lead the development of rocket motors and propulsion components of GPI. The Glide Phase Interceptor (GPI) is set to revolutionize regional hypersonic missile defense.
Its mission?
To launch specially adapted missiles from U.S. Navy surface warships that can intercept and neutralize incoming hypersonic missiles as they traverse the boundary between space and Earth’s atmosphere. These hypersonic missiles are capable of achieving speeds exceeding Mach 5, which translates to nearly 4,000 miles per hour and that is five times the speed of sound, posing a threat to regional missile-defense systems with their speed and maneuverability. Developing interceptors for them is a challenge.
The GPI interceptor is designed to be launched from the vertical launch systems on board the Navy’s Arleigh Burke-class destroyers. Its primary function is to intercept incoming hypersonic missiles during their glide phase of flight. In doing so, the GPI serves as a critical link between the Navy’s SM-3 and SM-6 missiles, both of which are designed to engage enemy missiles at different stages of their flight paths.
The design of the GPI prototypes will be compatible with the existing Aegis ballistic missile defense system, which operates from a naval vessel’s vertical launching system. The introduction of the GPI will necessitate the development of new interceptors and modifications to the Aegis weapon system to facilitate their launch. This represents a significant advancement in the field of missile defense technology.
The U.S. and Japan have previously co-developed, through a similar arrangement, the Raytheon Technologies-manufactured SM-3 Block IIA missile. While the new cooperative agreement would deliver a GPI capability in the 2030s, Congress last year said, in the fiscal 2024 National Defense Authorization Act, that it wanted to see MDA deliver an initial operational capability by the end of 2029 with a full operational capability by 2032, with at least 24 GPIs delivered by 2040.
This agreement between Japan and the U.S. is a significant step towards addressing the growing threat of hypersonic weapons. It not only strengthens the defense capabilities of both nations but also sets a precedent for international cooperation in the field of defense technology.
