Pentagon budget 2025: MDA seeks USD182 million for counter-hypersonic …

The Standard Missile-3 Block IIA missile, pictured, is jointly developed by the US and Japan. MDA suggested the GPI joint development with Japan will be pursued in a construct similar to that used for the SM-3 missile. (US Army)

The US Missile Defense Agency (MDA) has requested USD182 million in fiscal year (FY) 2025 “to continue development of Glide Phase Interceptor (GPI) capability to address hypersonic missile threats and continue maturation of critical technology elements”.

This is down from USD209 million requested in fiscal year FY 2024, but not yet received, and also down from the USD518 million total enacted in FY 2023.

GPI is in an early stage and Pentagon Comptroller budget documents – MDA did not brief its budget – said the requested funding would continue GPI “hypersonic defense prototype development for a FY 2034 delivery”.

In November 2021, MDA announced the award of Other Transaction Authority (OTA) agreements to Lockheed Martin, Northrop Grumman, and Raytheon for an accelerated prototype of a sea-launched GPI that could be integrated with the US Navy's Aegis Ballistic Missile Defense System. In June 2022, MDA selected Northrop Grumman and Raytheon to continue developing GPI.

Aegis interceptors operate in the terminal phase, and GPI is notionally designed to reach into a missile's glide phase, MDA officials said in 2023.

“[GPI] interceptors will be fired from US Navy (USN) Aegis Ballistic Missile Defense destroyers using the standard [Mk 41] Vertical Launch System (VLS) and will also be integrated with the modified Baseline 9 Aegis Weapon System, which is designed to detect, track, control, and engage hypersonic threats in the glide phase of the missile's flight,” the MDA has said. Aegis has cueing, launch-on-remote, and engage-on-remote capabilities; MDA planners have said GPI could fit well into that construct.