The Missile Defense Agency (MDA) on Sunday conducted the first flight test of a new three-stage booster for the Ground-Based Midcourse Defense (GMD) System’s Ground Based Interceptor (GBI), demonstrating variable stage usage.

The GMD aims to defend against a small number of longer range ballistic missiles from an opponent like North Korea, using the GBIs based in Fort Greely, Alaska, and Vandenberg Air Force Base, Calif.

MDA said this test entailed a GBI launching with a mock-up of the Exoatmospheric Kill Vehicle (EKV) which actually intercepts a missile and used a new three-stage booster operating in a two-stage mode. This means the third stage was not ignited, “allowing earlier release of the kill vehicle providing increased battlespace.”

Boeing [BA] said it helped conduct this new test as the prime contractor for the GMD system.

The company said this new capability was made possible via digital system modeling software upgrades and provides operators a real-time choice between two or three-stage interceptor, depending on threat location and speed.

Boeing added this test will allow the current GBIs to be modernized and fielded with this capability as part of the current Service Life Extension Program (SLEP).

Northrop Grumman [NOC] said it designed this upgrade and noted it has provided elements for the GMD program for over 20 years. It is also the lead provider of target vehicles for GMD testing.

The mock-up of the EKV was used for a “significant reduction in cost” to the test and spared defense assets not required in this non-intercept test, MDA said.

MDA called this a 2-/3-Stage selectable GBI and said it gives the warfighter more flexibility while “significantly increasing” the battlespace for a successful threat engagement.

“This was the first flight test of the new selectable stage booster configuration in two-stage mode. The system worked exactly as it was designed to do, and the results of this test provide evidence of the greatly increased battlespace the selectable booster brings to the Warfighter,” MDA Director Vice Adm. Jon Hill said in a statement.

“This test demonstrates that we continue to provide enhanced capabilities for our existing Ground Based Interceptor fleet while we rapidly design and deliver the leap ahead technology of the Next Generation Interceptor,” he continued.

The Next Generation Interceptor (NGI) aims to replace the canceled Redesigned Kill Vehicle (RKV) program to improve upon and ultimately replace the existing GBIs and includes a new booster as well as new kill vehicle.

20 NGIs are expected to start being fielded by 2028, with the last one deployed by about 2030. The Pentagon has not otherwise decided to replace the current 44 GBIs with NGIs.

In May, Hill said the current SLEP work on the GBIs is helping to bridge the gap until the NGIs are ready. Under the SLEP, MDA is removing the oldest GBIs from their silos, assessing their systems, changing out one-shot devices, changing out boosters,  updating processes, and recording hardware-based assessments for the stockpile reliability program (Defense Daily, May 19).

MDA said this new selectable stage booster gives the warfighter a greater defense in depth with more options for GBI usage. 

The agency underscored future upgrades to sensing and tracking capabilities, combined with this selectable stage booster, aim to let the warfighter assess the threat after initial engagement while having time to engage again, if needed.

“This is our first step toward a robust ‘shoot-assess-shoot’ capability,” Hill added.

The agency said initial indications are the test met requirements, but program officials will continue to evaluate system performance based on telemetry and other data from the test.

Earlier in September, MDA awarded Northrop Grumman a $422 million maximum ceiling value contract to deliver six more Boost Vehicles for the GBIs. The ordering period, including options, is expected to last through August 2031 (Defense Daily, Sept. 7).