Boost-phase defence and four layers of interceptors: Pentagon’s blueprint for Trump’s US$175b Golden Dome

Nevin Al Sukari - Sana'a - US President Donald Trump makes an announcement regarding the Golden Dome missile defence shield in the Oval Office of the White House in Washington May 20, 2025. — Reuters pic

WASHINGTON, Aug 16 — US President Donald Trump has picked a design for his Golden Dome missile defence system and named a leader of the ambitious US$175 billion (RM738.4 billion) defence programme. Here are some key details about the project:

How will it work?

The big new aim is for Golden Dome to leverage a network of hundreds of satellites circling the globe with sophisticated sensors and interceptors to knock out incoming enemy missiles after they lift off from countries like China, Iran, North Korea or Russia.

In April, the Pentagon asked defence contractors how they would design and build a network to knock out intercontinental ballistic missiles during the “boost phase” just after lift-off — the slow and predictable climb of an enemy missile through the Earth’s atmosphere. Existing defences target enemy missiles only midway through their travels through space.

The idea and new capability is that once the missile has been detected, Golden Dome will either shoot it down before it enters space with an interceptor or a laser, or shortly into its path of travel in space. Another new idea in the plan is to add additional defences on US soil.

A blueprint of the plan presented by the Pentagon to industry in August and first reported by Reuters, revealed that in addition to the space-based intercept layer, the system will have another three land-based layers.

An existing missile defence system named the Ground-Based Midcourse Defence system that uses land-based interceptors stationed in California and Alaska will be enhanced to create the second layer, according to the Pentagon presentation.

The concept unveiled in August also included a third layer consisting of five land-based launch sites intended to intercept inbound missiles while they are still in space. Three of those five would be located in the continental United States, while the remaining two would be in Hawaii and Alaska.

The fourth intercept layer would be for “Limited Area Defence”, meant to protect population centres. The concept includes new radars, a brand new “common” launcher that will launch current and future interceptors and may include the existing Patriot missile defence system. These would work in concert to defeat all threat types, such as hypersonic weapons and cruise missiles, the Pentagon said.

“I promised the American people that I would build a cutting-edge missile defence shield to protect our homeland from the threat of foreign missile attack,” Trump said when he made the announcement in May.

Is Golden Dome like Israel’s Iron Dome?

“We helped Israel with theirs, and [it] was very successful, and now we have technology that’s even far advanced from that,” Trump said, referring to Israel’s Iron Dome missile defence system.

The short-range Iron Dome air defence system was built to intercept the kinds of rockets fired by the Palestinian group Hamas in Gaza.

Developed by Israel’s Rafael Advanced Defence Systems with US backing, it became operational in 2011. Each truck-towed unit fires radar-guided missiles to blow up short-range threats like rockets, mortars and drones in mid-air.

The system determines whether a rocket is on course to hit a populated area; if not, the rocket is ignored and allowed to land harmlessly.

Iron Dome was originally billed as providing city-sized coverage against rockets with ranges of between 4 and 70 km, but experts say this has since been expanded.

How is it similar to then-president Ronald Reagan’s Star Wars initiative?

“We will truly be completing the job that President Reagan started 40 years ago, forever ending the missile threat to the American homeland,” Trump said in May.

The idea of strapping rocket launchers, or lasers, to satellites so they can shoot down enemy intercontinental ballistic missiles is not new. It was part of the Star Wars initiative devised during the presidency of Ronald Reagan. But it represents a huge and expensive technological leap from current capabilities.

Reagan’s “Strategic Defence Initiative,” as it was called, was announced in 1983 as groundbreaking research into a national defence system that could make nuclear weapons obsolete.

The heart of the SDI programme was a plan to develop a space-based missile defence programme that could protect the US from a large-scale nuclear attack. The proposal involved many layers of technology that would enable the United States to identify and destroy automatically a large number of incoming ballistic missiles as they were launched, as they flew, and as they approached their targets. SDI failed because it was too expensive, too ambitious from a technology perspective, could not be easily tested and appeared to violate an existing anti-ballistic missile treaty.

Who will build Golden Dome?

One-time Trump ally Elon Musk’s rocket and satellite company SpaceX had emerged as a frontrunner alongside software firm Palantir and drone maker Anduril to build key components of the system. But the effort may have faltered when the Trump administration side-lined the concept of Golden Dome as a paid-for service not owned by the government.

Many of the early systems are expected to come from existing production lines. Attendees at the White House press conference with Trump named L3Harris Technologies, Lockheed Martin and RTX Corp as potential contractors for the massive project.

L3 has invested US$150 million in building its new facility in Fort Wayne, Indiana, where it makes the Hypersonic and Ballistic Tracking Space Sensor Satellites that are part of a Pentagon effort to better detect and track hypersonic weapons with space-based sensors and could be adapted for Golden Dome.

But Golden Dome’s funding remains uncertain. Republican lawmakers have proposed a US$25-billion initial investment for it as part of a broader US$150-billion defence package, but this funding is tied to a contentious reconciliation bill that faces significant hurdles in Congress. — Reuters