The Government Accountability Office said the Missile Defense Agency ’s development plan for its next-generation interceptor for homeland defense carries both schedule and funding risk, according to a June 26 report from the watchdog.

MDA is developing the Next-Generation Interceptor after canceling a previous effort to field a redesigned kill vehicle in August 2019 for the ground-based interceptors which make up the Ground-Based Midcourse Defense system (GMD) designed to protect the U.S. homeland from intercontinental ballistic missiles from Iran and North Korea.

MDA wants to field NGI by 2028, but Congress is pushing for an earlier deadline and industry teams have said they could deliver initial interceptors by the fourth quarter of fiscal 2027, one year ahead of schedule .

“The NGI program is on track to start product development in 2024 but the program is planning to overlap design and production activities to accelerate flight testing,” the GAO report states. “Any major design issues could disrupt this strategy.”

GAO found NGI’s schedule to be “already optimistic when compared to development timeframes of similar weapon systems,” and added that the agency is also struggling to meet testing goals across the board, which could further derail the ambitious schedule.

The program’s cost has also gone up by hundreds of millions of dollars in the last year, the GAO found. Even so, it has yet to rise above planned funding levels.

Yet the GAO said, “MDA officials expect further increases due to supply chain issues and rising material costs.”

On time

MDA is working to field NGI by 2028 as threats grow rapidly in complexity and capability.

While the NGI program is meeting schedule goals now, GAO showed skepticism that NGI would maintain its timeline. Historically, the office said, comparable technology development has taken longer.

The agency is buying long lead materials for the interceptors, particularly for ones to be used in upcoming flight tests, but GAO notes NGI designs “are not yet mature, and any changes could necessitate rework on interceptors currently in early production.”

The agency was carrying two teams through a competitive design phase . Lockheed Martin and its Aerojet Rocketdyne partner completed the preliminary design review for its NGI in September 2023 and a Northrop and RTX team passed through the same design review at the end of January.

But nearly a year prior to a deadline for two competing teams to reach a critical design review phase, MDA chose Lockheed Martin in April to move forward rather than continue with both teams into the next phase of technology development.

According to the GAO report, both NGI contractors “made progress developing critical technologies” and MDA plans to assess NGI’s critical technology maturation status prior to a product development decision expected in the third quarter of FY24.

NGI’s schedule has flight tests beginning roughly six years after MDA awarded the development contracts. GAO noted that a 2019 study by a federally funded research and development center found “kill vehicles, satellites and strategic systems” take roughly seven years from contract award to first flight.

Flight test schedules will have an impact, the GAO said, and MDA has not been able to stay on track even for GMD testing. NGI production, the GAO notes, is contingent on completing three intercept flight tests within two years.

“GMD program has never successfully executed more than two intercept flight tests within a span of 2 years since the program started testing operationally configured GMD interceptors in 2006,” the report states.

“NGI might face similar challenges, in part, because DOD plans for NGI flight testing to increase in difficulty with each successive test,” it adds.

On budget

The GAO found the NGI program’s development cost has already increased in its “early stages.” The Pentagon has anticipated the program cost to be “a few billion dollars higher” than MDA’s early estimates, which is in line with the Cost Assessment and Program Evaluation (CAPE) office’s independent cost assessment in 2021.

“NGI’s costs remain within the program’s current funding level, but the cost growth accumulated in the first 3 years of the program has reduced the government’s funding margin as a result of accelerated schedules,” GAO states. Moreover, GAO said typically the most significant cost growth happens later in development and production.

The rising cost, according to the office, is mostly due to contractors taking steps to mitigate schedule risk as well as growing material costs “which directly related to supply chain issues and were further exacerbated by the COVID-19 pandemic.”

While MDA has traded cost for schedule in the first phases of the program, the agency did acknowledge that will not be “sustainable going forward,” the GAO notes.

Technical risk

In 2022, the Pentagon’s research and engineering branch found technical risk in the NGI program. MDA “disagreed” with a large portion of that assessment and GAO said the agency has “taken limited steps to address the identified risks.”

GAO reported MDA has completed all required survivability testing on component-level parts, but the agency “is not fully addressing risks associated with NGI’s threat requirements.”

And MDA is not “fully developing” models and simulation that it needs to verify technology maturity and performance, the report states.

GAO found other DOD components like GMD’s Technical Direction Agent, U.S. Northern Command, MDS Operational Test Agency and the DoD’s director of operational test and evaluation were concerned about the lack of modeling and simulation capabilities for the program and the agency’s ability to get the needed capabilities developed in time for ground testing expected in FY26.

“CAPE officials told us in February 2024 that foregoing adequate simulation capabilities directly amplifies risks to the program because MDA will be relying on these same models and simulations for verification activities in lieu of more extensive flight testing,” the report states. “CAPE officials added that insufficient modeling and simulation would potentially leave some of the most critical questions regarding NGI’s performance unanswered.”

But MDA told GAO that it would ensure “NGI-specific requirements for the MDS-level modeling and simulation framework are identified, planned for, and implemented,” according to the report. This includes aligning development of an all-digital MDS-level simulator with the program.

“DOT&E officials told us this new digital simulator will be essential for conducting NGI operational assessments because it will provide significantly greater simulations capabilities, once developed,” the GAO states.