Hypersonic Interceptors: US Wants Minimum 24 GPI Missiles By 2040 As Russia, China Gain Upper Hand

With the National Defense Authorization Act for the 2024 fiscal now cleared, the US Congress is pressing the Missile Defense Agency to deploy interceptors capable of defeating hypersonic missiles sooner than the anticipated schedule.

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The Glide Phase Interceptor (GPI), capable of intercepting a hypersonic missile in its glide phase of flight, is expected to be delivered in the early 2030s. However, despite the agency’s latest estimates, Congress called for the program to achieve operational capability by 2029 end.

As per the NDAA, MDA is required to deliver and deploy “not fewer than 12” Glide Phase Interceptors (GPIs) by the deadline they have suggested, besides demonstrating through tests that the interceptor can indeed counter and defeat hypersonic weapons, Defense News reported. 

In no ambiguous words, the act stipulates that the Pentagon must field “not fewer than 24 GPIs by the end of 2040” and that the program must achieve full operational capability by the end of 2032.

It further said that to achieve full operational capability, the GPI must be able “to be operated collaboratively with space-based or terrestrial sensors that the Department of Defense expects to be deployed before the end of 2032.”

The urgency shown by the Congress comes in the wake of burgeoning hypersonic threats from China, Russia, Iran, and North Korea. While China and Russia have operational hypersonic weapons, there is still some skepticism about claims made by Iran about its capability to deploy such weapons. Moreover, there is concern that North Korea may also have succeeded in accruing hypersonic technology. 

Hypersonic weapons travel at speeds five times faster than the speed of sound (Mach 5) and fly at low altitudes, making them difficult to detect with existing radars. Additionally, these projectiles can alter their trajectory, making them more challenging to target than conventional ballistic warheads, which fall to their targets on predictable trajectories.

Often regarded as invincible, the threat from these weapons springboarded the MDA into intensifying efforts to develop a hypersonic interceptor since the continent and its overseas territories remain defenseless against highly maneuverable hypersonic weapons.

Congress approved US$225 million in extra funding for hypersonic defense development initiatives, exceeding the agency’s request of US$209 million for FY24. To create the capability, lawmakers also permitted the MDA director to sign a joint development agreement “with one or more international partners.”

Although the act did not name an international partner, the United States has reportedly remained in talks with Japan to co-develop the hypersonic interceptor, akin to the initiative to develop and buy the Navy’s SM-3 Block IIA program.

In August, the Japanese media reported that Japan and the United States could agree to jointly develop a new type of missile to intercept hypersonic projectiles that are meticulously being developed and fielded by their common adversaries, such as North Korea, China, and Russia. 

At the time, there was speculation that an agreement to that effect would be expected to be reached at the US-Japan-South Korea trilateral summit scheduled for August 18. However, there has been no update on such an agreement since.

The Vaunted Glide Phase Interceptor Program

The Glide Phase Interceptor, a project of the Missile Defense Agency for hypersonic defense, is intended to shoot down incoming hypersonic missiles in their glide phase of flight, which occurs between the launch and terminal stages. The glide phase is when the missile is most vulnerable.

A boost-glide weapon capable of reaching hypersonic speeds is fired into the sky, where it glides until it hits its target. The “glide” phase of the missile’s trajectory is the best chance to intercept it before it enters its last high-speed drop. It is precisely what the Glide Phase Interceptor aims to do.

MDA Chief Vice Adm. Jon Hill previously explained: “So when you’re in the glide phase — higher up from the terminal, right, where a hypersonic vehicle is likely in its most vulnerable phase — that’s a pretty tough environment. And you can’t take an air defense weapon and operate it there, nor can you take a space weapon like an SM-3 and operate there; it’s just a different environment.”

US Interceptor Missile
File Image: US Interceptor Missile

The MDA initially chose the American defense firms Raytheon, Lockheed Martin, and Northrop Grumman to design the GPI. Northrop Grumman was awarded US$18.95 million for the first development, Lockheed Martin US$20.94 million, and Raytheon Missiles and Defense US$20.97 million. Later on, Lockheed Martin was pushed out of the contest.

The contract signed by Northrop Grumman and Raytheon requires them to “continue to develop further and improve their idea, leading to a system requirements review and prototype.”

As part of the MDA-led competition, Northrop Grumman and Raytheon Technologies, an RTX business, are working on creating hypersonic weapons interceptors separately. Both manufacturers have received about US$61 million in funding for the development of the interceptor.

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In addition to the GPI program, the MDA is working on a space-based system to counter the threat posed by elusive enemy missiles. In July, the US Space Development Agency (SDA) announced two additional contracts for a constellation of missile surveillance satellites. By 2025, the satellite system will be launched.

The MDA aims to build a multi-layered defensive system connecting military weapon systems, ground-based radar, and satellite-based sensors into a unified network to locate, track, and possibly intercept and destroy hypersonic missiles.

The Hypersonic and Ballistic Tracking Space Sensor, a recently created advanced hypersonic weapon tracking satellite from the MDA, may be combined with the GPI. The concept is based on the need to create a continuous “track” on a hypersonic missile traveling swiftly, as well as target detail networking and satellite missile tracking technology.

USS John Paul Jones Aegis BMD System Intercepts Target Missile
The GPI will be equipped on the Aegis BMD System.

The interceptors will be built to fit inside the Aegis Ballistic Missile Defense destroyers currently used by the US Navy. The updated Baseline 9 Aegis Weapon mechanism, which tracks, engages, and detects hypersonic threats, will be combined with the weapon and fired from its standard vertical launching mechanism.

The United States is under pressure from its adversaries, China and Russia, to create an interceptor to counter hypersonic weapons. This may explain why the NDAA calls for speeding up the development and deployment of the system. 

However, it is also widely understood that it would be mighty challenging to develop interceptors that can stop a hypersonic missile that can move at five times the speed of sound and maneuver during the glide phase of flight.