The US Missile Defense Agency (MDA) selected defense giant Northrop Grumman to continue developing the Glide Phase Interceptor (GPI) to detect, track, and take out hypersonic threats in their glide phase.
Lockheed Martin, Raytheon, and Northrop were originally chosen to work on GPI design concepts, but Lockheed was eliminated in June 2022 followed by Raytheon in September 2024 after a competitive selection process.
Under an existing Other Transaction Agreement, Northrop will refine the GPI’s preliminary design and demonstrate system performance in hypersonic environments before its preliminary design review.
In addition, it will complete flight experiments using flight-proven systems and use digital engineering to connect the entire GPI program to accelerate design processes and improve interceptor capability development.
The defense giant will work closely with the MDA and Japan’s Ministry of Defense following the May 2024 official GPI cooperative agreement between the US and Japan. MDA is leading the program, while Tokyo is developing rocket motors and propulsion components for the GPI.
The MDA sought $182 million for the GPI program in its 2025 fiscal year budget request.
Glide Phase Interceptor
The GPI is intended to intercept incoming hypersonic missiles that are still within the atmosphere but have completed their powered flight, known as the glide phase, which traditional air defense systems find difficult to counter.
The missiles will be fired from the US Navy’s Aegis Ballistic Missile Defense destroyers and Aegis Ashore using the standard Vertical Launch System.
According to Northrop, the GPI “includes advanced technologies, such as a seeker for threat tracking and hit-to-kill accuracy, a re-ignitable upper stage engine used for threat containment and a dual engagement mode to engage threats across a wide range of altitudes.”
It will also feature an open architecture to accommodate future enhancements, with a dual aero and rocket motor guided kill vehicle for low and high-altitude capability, rapid reloadable and modular software design, and energy flexible propulsion for maximum threat containment.
It is anticipated to reach initial operational capability by the end of 2029 and full operational capability by the 2030s, although MDA Director Lt. Gen. Heath Collins stated that achieving those timelines could be difficult due to the complexities involved in developing such advanced systems.
“We’ve been tasked to think creatively and bring capability sooner – ’29, ’30. And that is really going to take maybe some different style of thinking than traditional start with a – start a new weapon. We’ve got to figure out – it’s most likely got to be a weapon that already exists today. What can we do to get the most out of it?” he said at a Center for Strategic and International Studies event.
