The Congressional Budget Office estimates President Trump’s proposed Golden Dome space-based missile defense could cost about $1.2 trillion over 20 years, vastly higher than the initial $175 billion figure.

Earlier estimates suggested space-based components alone could run up to $542 billion over two decades, underscoring cost uncertainties tied to the program’s scope.

The program aims to defend against space and Earth threats, but experts warn space-based missile defense remains speculative and not yet a reality.

The proposal envisions a multilayer defense network—space, two surface layers, and a regional layer—potentially requiring around 7,800 satellites for nationwide coverage.

Experts note significant technical challenges, including scaling from Israel’s Iron Dome to the continental United States and the risk of being overwhelmed by ballistic missiles.

The article draws a parallel to Reagan’s SDI, noting past optimism followed by funding cuts as technology lagged expectations.

Officials say existing defenses haven’t kept pace with adversaries’ capabilities, reinforcing the argument for a broader, multi-domain defense system.

CBO notes its notional architecture targets a single wave of 10 ICBMs from regional adversaries, with potential changes to the plan depending on future decisions, including more interceptors or different platforms.

Even with heavy spending, the system wouldn’t be an impenetrable shield and could influence adversaries’ missile arsenals or tactics; deterrence depends on perceived capability and responses by peers like Russia and China.

Defending a larger area would require an impractically large number of orbiting weapons and ongoing costs, raising questions about viability and sparking controversy.

The article cites a report from U.S. authorities and notes reporting from the news agency dpa.

Acquisition costs would exceed $1 trillion, with the space-based interceptor layer making up roughly 70% of acquisition costs and 60% of total costs for a constellation of about 7,800 satellites.