The estimate is significantly higher than the initial projection of $175 billion (£129 billion).

“A national missile defence system possessing capabilities broadly consistent with those outlined in the executive order would cost about $1.2 trillion to develop, deploy, and operate for 20 years,” the report stated, noting that all costs are expressed in 2026 dollars.

Of the total projected cost, acquisition expenses alone would exceed $1 trillion, covering the system’s key components, including interceptor layers and a space-based missile warning and tracking system.

“That amount includes costs for the system’s major components—namely, the interceptor layers and a space-based missile warning and tracking system. It also includes costs for general, ongoing research and development and improvements in the system’s integration and performance,” the report added.

Trump unveiled the ambitious missile shield project shortly after returning to the White House, describing it as a necessary safeguard against “next-generation” aerial threats.

The CBO report identified the space-based interceptor layer as the most expensive part of the programme, accounting for nearly 70 percent of acquisition costs and 60 percent of total expenditure.

According to the assessment, the proposed system would be capable of fully countering an attack launched by a regional adversary with limited capabilities, such as North Korea, or a small-scale strike from near-peer rivals such as Russia or China.

However, the report warned that the system could be overwhelmed by a full-scale assault from a major military power.

Meanwhile, Russia has announced the successful test-firing of its RS-28 Sarmat intercontinental ballistic missile (ICBM), a nuclear-capable weapon widely described by Moscow as one of the most powerful missile systems ever developed.

According to the Kremlin’s official website, President Vladimir Putin hailed the launch as a major milestone, calling the Sarmat “the most powerful missile system in the world” and comparing it to the Soviet-era Voevoda missile currently in Russia’s arsenal.

Putin further claimed that the Sarmat’s total warhead yield is more than four times greater than that of any existing Western counterpart. Western defence analysts have nicknamed the missile “Satan 2.”

Military expert and air defence historian Yuri Knutov, speaking to Sputnik, said the missile’s defining capability is its ability to carry multiple independently targetable reentry vehicles (MIRVs), allowing each warhead to strike separate targets independently.

Knutov also argued that even advanced missile defence systems, including Trump’s proposed Golden Dome shield, could struggle to intercept warheads using suborbital trajectories and hypersonic manoeuvring capabilities, raising fresh questions about the effectiveness of next-generation missile defence architecture.