Army Modernization: Air and Missile Defense Efforts Would Benefit from Applying Leading Practices [Reissued with revisions on Jun. 18, 2025]
Fast Facts
Since 2018, the Army has ramped up its modernization of air and missile defense systems to protect equipment, personnel, and facilities from threats like cruise missiles and rockets.
The Army identified seven of these modernization efforts and increased its budget requests to $11.8 billion to support them. But the Army hasn't fully applied leading practices for product development to these efforts. For example, none of them used modern design tools such as digital twins—virtual models that can be updated in real time.
We recommended that the Army assess the benefits of using modern design tools to speed up its modernization efforts.
Lower Tier Air and Missile Defense Sensor
Reissued with a revision on June 18, 2025, to correct the figure title on the Highlights page.
Highlights
What GAO Found
The Army's air and missile defense mission is to protect soldiers, equipment, and facilities from air and missile threats, such as cruise missiles and rockets. These are capabilities that near-peer competitors, such as Russia and China, have invested in. To address these threats, the Army is pursuing multiple efforts to modernize its air and missile defense capabilities.
Army Futures Command is responsible for developing requirements for future Army systems. It identified four capabilities that the Army needs and developed requirements to meet those needs. For example, the Army developed requirements for a short-range air defense system, the Sgt. Stout.
Maneuver-Short Range Air Defense Sgt. Stout
Since 2021, the Army has identified seven air and missile defense efforts to develop and acquire needed capabilities and increased its requests in the President's Budget to support them. For example, the Army's requests for the efforts increased from $8.8 billion to $11.8 billion from fiscal years 2021 through 2025. The Army also chose acquisition pathways intended to speed development, production, and delivery of capabilities for most efforts.
The Army's development of the seven modernization efforts did not fully apply leading practices for product development. Most efforts use 3D modeling and simulation, in which a static representation of a product is tested with predefined data to understand how it will function in a specific situation. In contrast, leading companies use modern design tools like digital twins (dynamic virtual representations of products) and digital threads (common information sources) early and as part of an iterative development approach. Digital twins can enable design updates in real time. Digital threads connect stakeholders with real-time data across the product life-cycle to help inform decisions.
Fully using these tools can provide efficiencies, such as the ability to anticipate potential design flaws and reduce costs. Assessing the benefits and affordability of using these modern design tools can better position the Army to more quickly change designs than is possible with 3D modeling and simulations alone, speeding the delivery of capability to the soldier.
Why GAO Did This Study
Since 2018, the Army has focused on modernizing its air and missile defense systems to counter those of near-peer competitors.
A Senate report and the House report accompanying the National Defense Authorization Act for Fiscal Year 2024 include provisions for GAO to review and assess the Army's air and missile defense modernization efforts. GAO's report (1) describes how the Army developed the requirements to modernize these efforts; (2) describes how the Army is acquiring the systems; and (3) assesses the extent to which the Army applied leading practices for product development to these efforts.
GAO reviewed the Army's processes for identifying capability needs and developing requirements for air and missile defense efforts. GAO also reviewed the Army's acquisition approaches, analyzed its President's Budget requests since fiscal year 2021, and assessed the efforts against leading practices for product development that GAO identified in prior work. GAO interviewed officials from Army requirements and program offices and the Department of Defense.
Reissued with revisions on Jun. 18, 2025
Reissued with a revision on June 18, 2025, to correct the figure title on the Highlights page.Recommendations
GAO is making six recommendations, including that the Army should implement an iterative product development approach, and assess the benefits and affordability of implementing modern design tools for its air and missile defense efforts. DOD concurred with these recommendations.
Recommendations for Executive Action
| Agency Affected | Recommendation | Status |
|---|---|---|
| Department of the Army | The Secretary of the Army should ensure that Maneuver-Short Range Air Defense Increments 4 and 5, which incorporates new vehicle platforms, follows an iterative product development approach. (Recommendation 1) |
DOD concurred with the recommendation. In July 2025, the Army stated it will follow an iterative development approach for Maneuver-Short Range Air Defense (M-SHORAD) increments 4 and 5. The Army is currently in the requirements development phase for M-SHORAD increment 4 with plans to identify a minimum viable product by March 2028. It expects to complete development in September 2030. The Army has yet to start development for M-SHORAD increment 5, but it plans to identify a minimum viable product by March 2032 and complete development in September 2034.
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| Department of the Army | The Secretary of the Army should ensure that development of the new missile for the Indirect Fire Protection Capability follows an iterative product development approach. (Recommendation 2) |
DOD concurred with the recommendation. In July 2025, the Army reported it is using select aspects of an iterative development approach within its existing incremental development approach, such as continuous user feedback, to develop a new missile for the Indirect Fire Protection Capability. The Army expects to solicit user feedback through planned soldier touchpoints in 2027 and identify a minimum viable product, one aspect of iterative product development, by September 2028.
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| Department of the Army | The Secretary of the Army should ensure that the Integrated Battle Command System program assesses the practicality, benefits, and affordability of implementing a digital twin that incorporates both software and hardware. (Recommendation 3) |
At the time the report issued, DOD concurred with the recommendation. In June 2026, the Army provided documentation of an assessment that concluded the existing modeling and simulation efforts for IBCS are sufficient and identified that not all IBCS hardware has a digital twin. At the same time, the Army stated that a digital twin of all software and hardware is not required to adequately simulate the system in all potential operating conditions. The Army's actions meet the intent of the recommendation.
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| Department of the Army | The Secretary of the Army should ensure that Maneuver-Short Range Air Defense Increments 1, 2, and 3 efforts—Sgt. Stout, Directed Energy, and Next Generation Short Range Interceptor, respectively—assess the practicality, benefits, and affordability of implementing modern design tools, including digital twinning and digital threads. (Recommendation 4) |
DOD concurred with the recommendation. In July 2025, the Army reported that it is exploring implementation of modern design tools for Maneuver-Short Range Air Defense Increment 1, 2, and 3. For Increments 1 (Sgt. Stout) and 2 (Directed Energy), the Army expects to complete its assessment of implementing modern design tools by September 2026. The Army also reported in July 2025 that they considered implementation of modern design tools for M-SHORAD Increment 3, but determined implementation of a digital twin was not within the program's budget. The Army is, however, pursuing a digital thread for Increment 3 in addition to leveraging traditional modeling and simulation. The Army estimates it will complete implementation of the digital thread by September 2028.
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| Department of the Army | The Secretary of the Army should ensure that all variants of the Indirect Fire Protection Capability effort—to include the development of subsystems for Increment 2 as well as the High Energy Laser and High-Power Microwave efforts—assess the practicality, benefits, and affordability of implementing modern design tools, including digital twinning and digital threads. (Recommendation 5) |
DOD concurred with this recommendation. In July 2025 the Army reported that it was exploring the feasibility, benefits, and costs of implementing modern design tools such as digital twinning and digital threads for the Indirect Fire Protection Capability Increment 2 effort. The Army expects to complete this assessment by October 2027.
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| Department of the Army | The Secretary of the Army should ensure that the Lower Tier Air and Missile Defense Sensor effort assesses the practicality, affordability, and benefits, of implementing modern design tools, including digital twinning and digital threads. (Recommendation 6) |
At the time the report issued, DOD concurred with the recommendation. In February 2026, the Army published a digital engineering implementation plan for the Lower Tier Air and Missile Defense Sensor (LTAMDS) that identified that the effort is not currently implementing modern design tools, such as a digital twin, but may explore opportunities to do so in the future. Army officials also informed GAO that a digital twin was not practical or cost effective at that time because it would affect LTAMDS testing costs and schedules. These actions meet the intent of the recommendation.
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