US and Japan sign agreement to co-develop hypersonic interceptor

HONOLULU — The United States and Japan signed a cooperative agreement Wednesday to co-develop a hypersonic missile defense capability designed to neutralize hypersonic threats in the glide phase of flight, according to May 15 statements from both the Missile Defense Agency and Japan’s Defense Ministry.

The two countries have been in talks regarding the possibility for well over a year. The MDA is still early in the development process for the Glide Phase Interceptor , and the agency’s budget plan envisions a first fielding in the mid-2030s. Two companies are competing to design GPI – Raytheon Technologies and Northrop Grumman . Each contractor won contracts in June 2022.

During the Japan-U.S. summit meeting in August 2023, the governments announced they had begun working through a cooperative development agreement of GPI.

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.

Defeating a hypersonic weapon in its glide-phase of flight is a challenging technical problem, as the missiles can travel more than five times the speed of sound and can maneuver in flight, making it hard to predict a missile’s trajectory.

The GPI Cooperative Development Project Arrangement falls under the U.S.-Japan bilateral Memorandum of Understanding for Research, Development, Test and Evaluation projects, the U.S. government’s statement notes.

“By pursuing an agreement on GPI development, the U.S. and Japan will strengthen regional deterrence while enhancing longstanding missile defense cooperation between the two countries,” it states.

MDA will continue to lead the development of GPI for the Defense Department. As part of the agreement, Japan will “lead the development of rocket motors and propulsion components of GPI,” the U.S. statement says.

“In recent years, missile-related technologies such as hypersonic weapons have been dramatically improved and significantly enhanced in terms of both quality and quantity in the vicinity of Japan,” the Japanese MOD states in its own release. “Strengthening interception capabilities against these missiles is an urgent issue.”

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.

Jen Judson is an award-winning journalist covering land warfare for Defense News. She has also worked for Politico and Inside Defense. She holds a Master of Science degree in journalism from Boston University and a Bachelor of Arts degree from Kenyon College.

檀香山——据美国导弹防御局和日本防卫省5月15日发表的声明，美国和日本周三签署了一项合作协议，共同开发高超音速导弹防御能力，旨在消除高超音速威胁的滑翔飞行阶段。

两国就此可能性已进行了一年多的谈判。导弹防御局（MDA）的滑翔相拦截器（GPI）仍处于早期研发阶段，该机构的预算计划预计在2030年代中期进行首次部署。雷神技术公司和诺斯罗普·格鲁曼公司正在竞标GPI的设计工作。两家公司均于2022年6月中标。

在 2023 年 8 月的日美首脑会议上，两国政府宣布已开始通过 GPI 合作开发协议开展工作。

这些拦截器将设计用于美国海军配备宙斯盾弹道导弹防御系统的驱逐舰。该武器将通过标准的垂直发射系统发射，并与改进型的基线9宙斯盾武器系统集成，该系统能够探测、跟踪、控制和拦截高超音速威胁。

在滑翔阶段击败高超音速武器是一个具有挑战性的技术难题，因为导弹的飞行速度可以超过音速的五倍，并且可以在飞行中进行机动，这使得预测导弹的轨迹变得困难。

美国政府的声明指出，GPI合作开发项目安排属于美日双边研究、开发、测试和评估项目谅解备忘录的范畴。

声明指出：“通过就全球防空信息系统（GPI）的研发达成协议，美国和日本将加强区域威慑，同时深化两国之间长期存在的导弹防御合作。”

美国国防部声明称，MDA将继续主导GPI的研发工作。作为协议的一部分，日本将“主导GPI火箭发动机和推进部件的研发”。

日本防卫省在其声明中指出：“近年来，日本附近海域的导弹相关技术，例如高超音速武器，无论在质量还是数量上都得到了显著提升和大幅增强。加强对这些导弹的拦截能力迫在眉睫。”

美国和日本此前曾通过类似的安排共同开发了由雷神技术公司制造的SM-3 Block IIA导弹。

虽然新的合作协议将在 2030 年代提供 GPI 能力，但国会去年在 2024 财年国防授权法案中表示，希望看到导弹防御局在 2029 年底前交付初始作战能力，在 2032 年前交付全面作战能力，并在 2040 年前交付至少 24 个 GPI。

珍·贾德森是一位屡获殊荣的记者，为《防务新闻》报道陆地战争。她也曾为《政治报》和《内幕防务》工作。她拥有波士顿大学新闻学硕士学位和凯尼恩学院文学学士学位。