A ground-based interceptor is launched from Vandenberg Air Force Base, California, toward a ballistic missile target launched from Alaska during a test Dec. 5, 2008. (Photo courtesy of the Missile Defense Agency)

TOKYO — Japan plans to publicly award a contract for work on a joint US-Japanese Glide Phase Interceptor program by March 2025, the head of the Japanese defense ministry’s guided weapons efforts told Breaking Defense in a recent interview.

On May 15 Washington and Tokyo signed off on a formal agreement for GPI co-development that tasks Japan with building “rocket motors and propulsion components” for the interceptor, built to take down hypersonic weapons during the glide phase of flight.

The Pentagon said the joint project “will deliver a regional defensive capability over time as part of a holistic layered defense architecture.” The US Missile Defense Agency, which is leading the overall development effort, is expected to choose either Northrop Grumman or RTX as the prime contractor by the end of fiscal 2024.

Meanwhile, Japan will award a contract for its own work on the program “by March next year,” said Kazuya Yonekura, director of guided weapons project management division of the Japanese ministry of defense (MoD).

“Regarding the Japanese company which will be participating in this GPI project, we are going to do the public offering and then we’ll award a contract to a company,” Yonekura during a May 22 interview at MoD headquarters in downtown Tokyo.

He declined to comment on what companies are in the running for the contract, and the MoD declined to say if multiple companies are expected to bid. The MoD “will select a company through a public offering at an appropriate time,” a spokesperson said.

The ministry plans to spend 75.7 billion yen, or $480 million, for the GPI program this fiscal year.

One potential entrant is Mitsubishi Heavy Industries — Japan’s largest defense contractor —  which showcased GPI concept art and listed it as a program of interest in a November 2023 defense business strategy presentation available online. An MHI spokesperson confirmed the company’s interest the GPI program but declined to provide further details.

If Northrop wins the primary contract, it plans to split work with Japan on a 50-50 basis, said Jonathan Welch, Northrop’s capture and business development manager for launch vehicles.

“We have been working directly with Japan for the last year, year and a half now — and the Missile Defense Agency — to come up with that work-share split,” he said during an interview in Tokyo.

Although the US government restricted some GPI technologies to US developers, Welch said the potential GPI primes were able to negotiate the exact terms of how work would be divided with Japanese companies.

While Japan “excels” in certain areas of missile defense development, there are other technology areas where it wants to advance its its technology development and production capabilities, he said. “We think that the agreement we have for the cooperative development leverages both of those [areas].”

In response to questions from Breaking Defense about its GPI bid and its work with Japanese counterparts, a spokesperson for Raytheon, the defense arm of RTX, provided a statement saying the company “is committed to supporting the U.S. and Japanese government objectives for the GPI program and to rapidly field this critical capability.”

RTX and Northrop were put on contract to develop GPI in June 2022 after the elimination of competitor Lockheed Martin. The program began its “technology development” phase in April 2023.

Earlier this year, MDA made the call to downselect to a single competitor in 2024 — five years earlier than expected — with deployment now planned for 2035.

Welch said Northrop expects MDA to made its downselect decision by the “end of summer” with a modification to the current contract occurring in November for the winning company. The preliminary design review will occur “no later than 2030,” he added.