Golden Dome would radically reshape military doctrine and further militarise space. Photo / 123RF
Since ordering the Pentagon in January to erect a United States missile defence shield partly based in space, President Donald Trump has claimed that it would be completed by the end of his term and cost US$175 billion ($300b).
His signature national security effort will have close to a 100% success rate, he has pledged, “forever ending the missile threat to the American homeland”.
The White House and Pentagon have revealed scant details of the “Golden Dome” project, which defence and budget analysts say is likely to take at least a decade to complete and cost a trillion dollars or more.
Golden Dome would radically reshape military doctrine and further militarise space, an effort that’s been compared to the rush to build the atomic bomb during World War II and the Apollo moon landings.
Yet it still may not come close to providing the kind of comprehensive protection Trump says it will.
Marking a historic break from decades of nuclear deterrence, it would either remedy a glaring vulnerability to the US homeland or ignite an arms race in orbit that could last a generation or more.
Critics deride the most ambitious part of the programme - flooding low Earth orbit with thousands of satellites to detect and take out adversaries’ missiles - as a fantasy that will only destabilise the fragile international order that has prevented nuclear war for more than 70 years.
“Golden Dome could be the single most dangerous idea Trump has ever proposed, and that’s saying something,” Representative Seth Moulton (Democrat-Massachusetts), a member of the Armed Services Committee, said in an interview.
Proponents counter that because of expanding threats, as well as dramatic technological advances, the time is right to resurrect the Reagan-era Strategic Defence Initiative, known as “Star Wars”, that fizzled out at the end of the Cold War.
For years, defence hawks have pushed for a more robust missile-defence shield, citing the unsettling truth that the US doesn’t have a comprehensive way to protect its homeland.
China and Russia are already expanding their nuclear arsenals in the largest long-range weapons build-up since the Cold War.
They are adding hundreds of intercontinental ballistic missiles as well as new weapons systems, including hypersonic weapons designed to speed toward US cities at more than 6440km/h according to intelligence officials.
The US has neglected its homeland missile defence systems, said Tom Karako, director of the Missile Defence Project at the non-partisan Centre for Strategic and International Studies (CSIS).
The US$25 billion Trump dedicated to Golden Dome this year is a “down payment to blot out the years of inattention to this. We’ve known these threats are coming,” he said during a CSIS event. “It’s long overdue.”
The nation’s existing long-range ballistic missile defence system is designed to track an enemy missile when it is launched and follow it through its “boost phase” into “midcourse phase” as it travels towards US territory.
The US deploys sophisticated “kill vehicles” from bases in Alaska and California to target incoming enemy missiles.
The current system is only designed to thwart a small number of missiles from North Korea, not an attack from China or Russia.
Once an incoming missile is detected, the US would probably fire at least two missiles to attempt to intercept it.
There have been several tests of this existing system in which the kill vehicle didn’t hit anything.
Potential adversaries say they view Trump’s plan as an aggressive escalation.
China said it will “heighten the risk of turning space into a war zone and creating a space arms race and shake the international security and arms control system”.
Mao Ning, a spokesperson for the Chinese Foreign Ministry, said at a news conference: “We urge the US to give up developing and deploying [a] global anti-missile system, and take concrete actions to enhance strategic trust between major countries and uphold global strategic stability”.
Golden Dome would be modelled, at least in theory, after Israel’s Iron Dome, which has proved robust against attacks for years.
Israel’s missile defence only protects against short-range missiles, in an area about the size of New Jersey. Golden Dome would have to protect the entire US from intercontinental ballistic missiles that could be carrying multiple nuclear warheads.
An analysis by the Congressional Budget Office forecast the cost of deploying space-based interceptors alone would cost US$542b over 20 years.
That amount would only allow the Pentagon to defend against one or two missile launches from a rogue attack from North Korea.
To expand the system to counter a larger number of threats, some experts predict it could become one of the most expensive initiatives in the Pentagon’s history.
Todd Harrison, a senior fellow at the American Enterprise Institute, has calculated that a robust defensive architecture for Golden Dome could cost as much as US$3.6t over 20 years.
In May, Trump appointed Space Force General Michael Guetlein to oversee the Golden Dome effort, handing him what is perhaps the most difficult job in Washington.
When Trump pledged that the program could be completed in three years for US$175b, Harrison said: “He bounded the initiative in such a way that it’s impossible to meet all those expectations. They just don’t add up.”
Guetlein, he added, now has “to figure out how close he can come. The question is, where do you let the President down?”
With the project still in its infancy, it’s not yet clear which agency will lead Golden Dome. The money behind the effort has already sparked a race between US defence contractors - from Lockheed Martin to Booz Allen Hamilton and L3 Harris - who are eager to capitalise on what could be a once-in-a-generation spending spree.
Defence officials have made it clear that they also want contributions from tech companies, such as Anduril, Palantir, and SpaceX, that have driven innovation.
“If we want to use space effectively, we have to be ready to fight for it,” General Chance Saltzman, the Space Force’s chief of space operations, said in an interview.
“These are not emerging threats. These are threats that are on orbit. They are on the ground now and they are holding our assets at risk.”
The Pentagon operates several different missile defence systems, including Aegis, Thaad, and Patriot, which are designed to thwart short- to medium-range missile attacks and used to protect US military bases abroad.
To safeguard the US homeland, the military relies on what is known as the “ground-based midcourse defence system”, which is composed of just 44 interceptor missiles loaded like bullets in white-domed silos buried in the tundra of Alaska’s Fort Greely and along California’s coast at Vandenburg Space Force Base.
If a missile attack were detected, the domes would crack open and out would shoot a multi-stage rocket, trailing a tail of fire. As it flew towards the target, satellites would continue to relay data - how fast the incoming missile is travelling, its altitude and trajectory, while radar stationed on the ground and at sea would do the same.
Once in space, the US interceptor would release a strange-looking spacecraft, 1.4m-long, weighing 65kg, with thrusters and fuel tanks and a sensor that sticks out like a horn.
Odd though it may look, the “exoatmosphere kill vehicle,” as it is called, is designed to hunt its prey by whizzing through space at thousands of kilometres per hour and then destroying incoming missiles by colliding into them - a feat that experts say is akin to “hitting a bullet with a bullet”.
In the 20 tests conducted since 1999, however, the kill vehicles have missed their targets about as often as they’ve hit them, succeeding just 55% of the time, according to a report by the American Physical Society, a scientific non-profit.
And even then, the tests haven’t always accurately simulated real-world conditions. The trials “have been conducted under scripted conditions and designed for success”, the report said. “The Pentagon has consistently rated the tests as low in operations realism.”
The costs have been enormous. The US has spent more than US$350b on efforts to defend against nuclear-armed intercontinental ballistic missiles over the past 60 years, according to Laura Grego, a research director at the Union of Concerned Scientists.
The effort, she’s written, “has been plagued by false starts and failure, and none have yet been demonstrated to be effective against a real-world threat”.
Given the immense difficulty of hitting missiles well into their flight, military leaders have long sought to target them shortly after launch, during what’s known as “boost phase” when their engines are still firing and they’re easier to see.
Under Golden Dome, interceptors would be stationed in low Earth orbit and quickly swarm to the target during the short boost phase, kamikaze style.
During Reagan’s Strategic Defence Initiative, the space-based interceptor programme was called “Brilliant Pebbles”.
In the 1980s, launching and operating constellations of small satellites was dismissed as science fiction, which is one of the reasons Reagan’s plan was derided as “Star Wars” and ultimately ended up failing.
Since then, satellite technology has made enormous progress while the costs to launch spacecraft has dropped dramatically.
With its Starlink internet satellite system, which comprises more than 8000 operational spacecraft, SpaceX has demonstrated that it’s feasible to operate a large constellation and to launch rockets at a high rate. It sent up more than 130 rockets last year, and it’s aiming for more this year.
A key component of the proposed “Golden Dome” system is to bolster defences with an extensive array of orbiting kill vehicles.
Such a system would be ready to intercept an incoming missile much earlier, possibly during its “boost phase”.
Multiple orbiting interceptors could be deployed against an attack, making success more likely.
“Physics hasn’t changed,” said Clayton Swope, the deputy director of the aerospace security project at the Centre for Strategic and International Studies. “But what has are launch costs are so much lower and we’ve shown we can operate constellations of satellites in orbit. That was a question as recently as 10 years ago.”
At the same time, threats have grown and they will continue to “expand in scale and sophistication”, according to the Defence Intelligence Agency.
During the Cold War, the US was focused on a single adversary: the Soviet Union. Today, a host of other nations beyond Russia - including China, North Korea, Iran and Pakistan - have access to long-range missiles, and a total of nine countries possess nuclear weapons.
China is on track to nearly double the number of its ICBMs by 2035 and quintuple its arsenal of cruise missiles, according to the DIA.
Russia is also expanding its missile caches, the report said. And both countries are working to develop new long-range weapons systems, including hypersonic vehicles, which can manoeuvre and fly at speeds greater than Mach 5, making them difficult to track and target.
For decades, the US has relied on a doctrine known as “mutually assured destruction”: Any launch of a nuclear missile towards the US would result in a devastating US counterattack.
Given the arms race already under way, Golden Dome proponents argue, the US needs stronger defence systems to deter the new threats.
In addition to defending against missile strikes, Swope said, Golden Dome could serve as a Swiss Army Knife-like tool that could be used to attack other satellites or target rockets launching military payloads.
It would, he wrote in a report, “immensely enhance US space superiority beyond missile defence alone and create a potent deterrent effect”.
In an interview, he said: “We hear about warfighting in space, but now we’re talking about war fighting from space”.
In the end, it’s the sheer maths of Golden Dome that is giving many experts pause.
It would require a mind-boggling constellation of satellites in orbit to ensure that there was one in range of a missile attack at any time, defence analysts say. It would take “about 950 interceptors spread out in orbit to ensure that at least one is always in range to intercept a missile during its boost phase”, according to Harrison, the senior fellow at AEI.
If an adversary launched 10 missiles, it would require at least 9500 interceptors in space.
Others have said the numbers are even higher. The American Physical Society estimates that 16,000 interceptors would need to be stationed in orbit to take out an attack of 10 ICBMs.
“You need so many more interceptors than missiles, it becomes operationally impractical,” Harrison said.
Making Golden Dome work as advertised would entail a large number of satellite deployments at an enormous cost.
Even were this arrangement to prove as robust as Golden Dome’s proponents envision, it would still present a theoretical Achilles’ heel.
Such a dense pattern of orbiting satellites could be vulnerable to threats from, say, a nuclear detonation in space, which would knock out many of the Golden Dome weapons as well as generating a Kessler cascade of destructive orbiting debris that could silence the entire network.
Without a complete blanket of security, deterrence will remain the most crucial principle, said Doug Loverro, who served in various roles at Nasa, the National Reconnaissance Office and the Pentagon, including as deputy assistant secretary of defence of space policy.
If flooding Earth orbit with thousands of suicide satellites isn’t feasible, the Pentagon could make real progress building out its ground-based systems well beyond the 44 interceptors it already has, he said. But even that would not give the US total protection.
“Everyone knows we’re not going to be able to intercept a mass strike,” Loverro said.
“The question we have to entertain is how many missiles do we have to defend ourselves against in order to get the nuclear sabre-rattling to back down?”
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