[Discussion] U.S. Missile Shield Plan Could Cost $1.2 Trillion, CBO Says

CBO Estimates Long-Term Cost and Scope

The Congressional Budget Office said May 12 that the proposed “Golden Dome for America” missile defense architecture could cost about $1.2 trillion over 20 years. CBO’s estimate, totaling $1.191 trillion, includes roughly $1.025 trillion in acquisition and average annual operation and support costs of about $8.3 billion. The office said the figure reflects a broad mission set: defense of the entire United States, including Alaska and Hawaii, against ballistic, hypersonic, cruise missile, and other aerial threats through multiple overlapping layers.

CBO’s estimate is far above the $185 billion figure previously associated with Pentagon planning, but the gap appears tied to different assumptions on time frame, architecture, and which budget accounts are included.

Space-Based Interceptors Drive the Largest Share

The largest cost element is a boost-phase interceptor layer in low Earth orbit. CBO modeled 7,800 interceptor satellites in near-polar orbits at about 300 to 500 kilometers altitude. The constellation is sized to counter a raid of 10 intercontinental ballistic missiles launched nearly simultaneously, with two intercept attempts per target.

The concept relies on destroying missiles during the first three to five minutes of flight, before they can deploy reentry vehicles or penetration aids. CBO said that because satellites in low orbit are constantly moving and subject to atmospheric drag, sustaining 7,800 on station would require roughly 30,000 interceptor satellites over 20 years, with replacement about every five years.

Ground and Surface Layers Expand Coverage

For exo-atmospheric midcourse defense, CBO included the existing Ground-Based Interceptor field at Fort Greely, Alaska, plus two new upper wide-area sites. Each new site is modeled with 60 Next-Generation Interceptors in silos, a Long-Range Discrimination Radar, a command facility, and local THAAD and Patriot PAC-3 MSE defenses to protect the site itself.

The lower wide-area layer would add four Aegis Ashore sites equipped with SPY-6 radars, Mark 41 launch cells, and 48 SM-3 Block IIA interceptors each. CBO estimated deployment at nearly $4 billion per site and annual operating costs at about $170 million. Supporting systems would include over-the-horizon radar, Sentinel radar, THAAD, Patriot MSE, and counter-drone defenses.

Regional Sectors and Tracking Network

CBO’s homeland air and missile defense grid centers on 35 regional sectors. Each would include a command center, one Aegis-based radar, 24 Sentinel MPQ-64A4 radars, eight Glide-Phase Interceptors, four SM-3 Block IB missiles, 20 SM-6 Block IB interceptors, 32 THAAD interceptors, and 84 Patriot MSE missiles. CBO estimated this regional layer at $187 billion over 20 years.

The plan also depends on a major sensor network: 108 tracking satellites in low Earth orbit and 27 in medium Earth orbit, at an estimated 20-year cost of $90 billion. The purpose is to detect launches, maintain tracking on ballistic and hypersonic threats, and provide targeting data to ground radars and interceptors.

Limits, Industry Demands, and Strategic Effect

CBO said the notional architecture would be most effective against limited attacks by regional adversaries or smaller strikes by a peer state. It emphasized that the ability to engage incoming weapons does not guarantee a successful intercept. A large-scale Russian or Chinese strike could still saturate the system through volume, decoys, maneuvering payloads, cyber and electronic attacks, or strikes on satellites and supporting infrastructure.

The U.S. Space Force has already awarded contracts worth up to $3.2 billion to 12 companies for space-based interceptor work. Major contractors, including Lockheed Martin, Northrop Grumman, RTX, Boeing, and launch providers such as SpaceX, are expected to compete for larger roles. CBO said schedules will depend not only on funding, but also on industrial capacity for satellites, interceptors, radars, software, launch services, and communications networks.

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