U.S. Golden Dome defense estimated to cost $1.2 trillion

The Trump administration’s planned national missile defense system would cost about $1.2 trillion to build and operate for 20 years, according to Congress’ budget watchdog. The Congressional Budget Office, or CBO, estimated the cost of the project, dubbed the Golden Dome, on Tuesday. The Defense Department previously estimated the cost at $185 billion over the next decade, according to the CBO. The department did not appear to have publicly commented on the CBO estimate as of Wednesday morning.

The nonpartisan budget agency said that since the Defense Department had not released any details on which systems would make up the defense project, its experts used Trump’s January 2025 executive order on the system to determine what capabilities the government was likely to develop.

How would the U.S. build the Golden Dome? The CBO estimate is based on the concept of a four-layer system:

• A space-based layer of satellites with missile interceptors and a warning and tracking system.

• Two surface-based interceptor layers to cover wide areas of the United States.

• A layer focused on regional sectors.

The space-based layer would account for 60% of the project’s total costs, the budget office said. The CBO estimate also factors in costs for sensors and communication and management systems, as well as compensation for employees running and maintaining the entire array.

How well would the potential system work? The system would cover the entire United States, including Alaska and Hawaii. It could fully engage missiles from an adversary with limited capabilities, such as North Korea, or a small-scale attack from an adversary with a more powerful military, such as China, according to the CBO. For example, the space-based layer alone would likely be able to intercept 10 simultaneously-launched intercontinental ballistic missiles in the first three to five minutes after launch. However, an adversary with capabilities similar to those of the United States could overwhelm the Golden Dome with a full-scale attack, in the budget office’s estimation. 

Dig deeper: Read Christina Grube’s report on Trump’s plans for the Golden Dome.