Would Trump's Golden Dome keep the US safe – and do space lasers work?

Sydney Morning Herald

02-06-2025

It's 1983 and relations between the superpowers are close to an all-time low. Their arsenals of nuclear weapons are multiplying. The USSR alone is estimated to have more than 1000 missiles capable of crossing continents and more in submarines that could lie submerged off the coast of New York or Los Angeles, ready to sow Armageddon.
The US, meanwhile, has provocatively stationed low-flying cruise missiles, seen as 'first strike' weapons, at Greenham Common airbase outside London. Protests erupt. Both nations adhere to a strategy known as Mutually Assured Destruction (MAD), the knowledge that if one were to strike first, the other would have just enough time to launch a devastating counter-blow. Even US president Ronald Reagan finds it bewildering. 'It is inconceivable to me,' he says, 'that the great nations of the world will sit here, like people facing themselves across a table, each with a cocked gun, and no one knowing whether someone might tighten their finger on the trigger.'
There must be a better way, he thinks. And some prominent scientists, such as physicist Edward Teller, 'father of the hydrogen bomb' and arch-rival to atom-bomb developer Robert Oppenheimer, tell him there might be.
The US, they believe, has the capability to build a network of defences high in the sky that could stop Russian missiles dead in their tracks, using satellite-borne lasers to blow them up harmlessly in space. In March 1983, Reagan announces an ambitious program in a televised address: the 'Strategic Defence Initiative', which is immediately dubbed 'Star Wars' for its resemblance to the 1977 George Lucas film, which featured a laser-equipped space station called the Death Star (and Chewbacca, played by an actor in a furry suit).
It turns out, of course, that the scientists had promised more than they could deliver. There were never any giant space lasers. But the idea didn't vanish completely. And now Donald Trump, a president who's already made waves for his elaborate madcap schemes (trying to buy Greenland, turning Gaza into a beach resort), wants his own space-based missile defence system called the 'Golden Dome'.
Forty years on from Reagan's dream, could a defence shield now be possible? Would it make nuclear weapons obsolete? And what are 'Brilliant Pebbles'?
What do we know about Trump's Golden Dome?
In January, the president made an executive order calling for what he described as an 'Iron Dome for America', a reference to the Iron Dome air defence system that Israel has deployed, with some success, since 2011 to shoot down rockets fired from Gaza, Lebanon and Iran.
Trump's order stated that since Reagan's time in office, the threat from strategic weapons had become more intense and complex; next-generation missiles were now 'a catastrophic threat' to the United States. It said that while some existing interceptor systems could counter 'rogue-nation threats' (presumably from North Korea, which has a fairly advanced ballistic missile program, and possibly Iran, which is believed to have nuclear weapons capability), they had not kept up with 'peer and near-peer adversaries' – that is, Russia and China.
The solution would be a 'next-generation missile defence shield' to safeguard the US homeland from all possible airborne threats. These include intercontinental ballistic missiles (ICBMs, which shoot out of concrete silos then fall to Earth on a parabolic arc, and their submarine-based cousins); ordinary cruise missiles (which look like planes and are slow but can evade detection by flying low); as yet theoretical 'fractional orbital bombardment systems' that live in space, flinging bombs down from on high; a new breed of hypersonic cruise missiles (much faster than cruise missiles); and so-called hypersonic glide vehicles (which are boosted to the edge of space on a rocket then continue under their own steam).
No single defence weapon can neutralise all these. ICBMs have a predictable course but build up to a tremendous speed as they arc through space; hypersonic weapons fly lower but can manoeuvre in flight to evade detection. What we do know is that what Trump is calling the Golden Dome will incorporate many technologies. These include existing ground- and sea-based missile systems and – in a nod back to Star Wars – a new suite of anti-missile weapons based in orbit, where they might, if successful, destroy incoming ICBMs in the so-called 'boost phase', when they burn rocket fuel to reach space, and, ideally, before they break into multiple separate warheads that would have to be targeted individually. (Why 'Golden Dome'? Because it's Trump's favourite colour – the Oval Office is filled with golden knick-knacks he's collected.)
While Reagan was not deluded about the scale of the task back in the '80s – 'It will take years, probably decades, of effort on many fronts,' he acknowledged – Trump, buoyed by scientific advances in the intervening years, is more bullish. 'We'll have it done in about three years,' he said. 'Once fully constructed, the Golden Dome will be capable of intercepting missiles even if they are launched from other sides of the world and even if they are launched from space.'
Defence Secretary Pete Hegseth elaborated slightly: 'Some US technology in space, such as space-based sensors and air and missile defence, exists today, but all of the systems comprising the Golden Dome architecture will need to be seamlessly integrated. Golden Dome will be fielded in phases, prioritising defence where the threat is greatest.' Meanwhile, if Canada wants in, it needs to come up with a $US61 billion entrance fee, Trump has said on social media, or it's 'ZERO DOLLARS if they become our cherished 51st State'.
Is any of this 'dome' technology even possible?
'I don't think it's fantasy land,' says Malcolm Davis at the Australian Strategic Policy Institute. 'There are aspects of it that are very aspirational and probably won't be achieved on schedule or on budget, but there's also aspects of it that are practical.' What is a fantasy is Trump's timeline, he says. 'This could take 10 years to develop, and it will cost a lot more than what Trump is anticipating.'
Much of the technology required by Golden Dome has come a long way since the failure of Star Wars – at least, the bits that would be stationed on Earth. (The US has actually been exploring the idea since World War II, when its troops in Europe were threatened by Germany's V2 ballistic rockets.) Today, several countries have missile 'shields', including China, India, Israel, Italy, Russia and Turkey – South Korea is reportedly working on its own home-grown 'dome' – but nothing is at the scale or level of reliability that would be required to defend the entire US homeland.
Israel, for example, is smaller than Hawaii and has faced less technologically sophisticated foes – nothing like the peer-level arsenal the US wants to shield against. 'US Navy ships are very capable in shooting down cruise missiles and drones, but they're essentially trying to defend one point, which is themselves,' says Marcus Hellyer, head of research at the think tank Strategic Analysis Australia. 'The more you scale it up from defending one point to a small area such as Israel to large areas such as Ukraine and then on to the continental US, the degree of difficulty and, of course, cost increases as well.'
To successfully shield the US from nuclear attack, defensive interceptors would have to detect and destroy ICBMs that travel at speeds in excess of 24,000km/h. 'Defending against ballistic missile attacks is a challenging technical undertaking,' the Congressional Budget Office noted in a 2004 investigation into the practicalities of missile defence. 'In the case of ICBMs, a defensive system may need to hit a warhead smaller than an oil drum that is travelling above the atmosphere … countermeasures such as decoy warheads that may be carried by ICBMs further complicate the problem of intercepting targets.'
It's possible to do it from the ground, as a successful military test showed in 2017, but that was under well-rehearsed conditions. 'Engaging ICBMs is not computationally hard because they fly on a simple parabolic arc,' says Sidharth Kaushal at the Royal United Services Institute in London, one of the world's oldest military think tanks. 'But given the speeds involved, it requires a very rapid hand-off of data between multiple systems. Engaging hypersonics is more complex, in computational terms, given the capacity of hypersonic glide vehicles to manoeuvre and their ability to fly beneath surface-based radar for longer than ballistic missiles.'
In any case, the current arsenal of interceptors is far too small to provide adequate defence and would be immediately swamped by an attack from a major power, which would likely send many hundreds of missiles, each containing multiple warheads that would have to be targeted individually. The Federation of American Scientists calculates China already has some 600 warheads, with more on the way. The US has some 3700; Russia has more than 4000 (including those that are inactive). Meanwhile, the US has just two bases for what it calls its 'mid-course mis­sile defence pro­gram' with the firepower to specifically target incoming intercontinental nuclear-tipped ICBMs: Fort Greely in Alaska, which has 40 interceptor rockets, and Vandenberg Space Force Base in California, which has four. The rockets are built by Boeing and have a 'kill vehicle' – made by US aerospace manufacturer Raytheon – that detaches from a booster to engage the enemy in orbit, during the 'mid-course' phase of flight.
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The US also has numerous smaller units that can engage with shorter-range missiles, planes and drones, such as the Aegis ship-board system, the Patriot system used by Ukraine against Russian attacks, and the missile batteries known as Terminal High Altitude Area Defence, or THAAD, which have been successfully used by Israel. Some of these systems could conceivably attempt to intercept ICBMs but would be likely to have a lower strike rate than the much larger rockets deployed in the mid­-course mis­sile defence pro­gram.
In short, shielding the entire US is likely to cost far more than the White House claim of $US175 billion ($270 billion). Weapons company Lockheed Martin, which already makes anti-missile weapons, has likened the Golden Dome to the Manhattan Project (the World War II program that built the atom bombs dropped on Japan) in the scale of its ambition. It will probably top the $US260 billion (in today's money) that funded the Apollo space program through the '60s until 1972. In 2021, Princeton's Frank von Hippel calculated the US had already spent some $US280 billion (in today's dollars) over the previous four decades on anti-missile programs. Star Wars fizzled not only because technology didn't catch up in time, but because of the enormous drain on taxpayer dollars that subsequent administrations decided were better deployed elsewhere, particularly after the collapse of the Soviet Union in 1991. Democrat senator Ed Markey has branded Golden Dome ' economically ruinous '.
'Mega-projects' like this go wrong, says Marcus Hellyer, 'because you don't understand the requirements, and the requirements keep blowing out. And as the requirements blow out, so does the technical difficulty, and therefore the cost and schedule. And, at the moment, Golden Dome's requirements are essentially unbounded.'
What about the space lasers?
Miniaturisation, and vast improvements in computing power and data storage, not to mention AI, make the idea of a space defence that can co-ordinate attacks autonomously seem much more technologically feasible than in Reagan's era. Satellite networks such as Elon Musk's 7000-strong Starlink have already proved it is economically possible to launch thousands of small objects into orbit.
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The not-insignificant hurdle that remains, once these things are in space, is successfully destroying enemy missiles. Do interceptors shoot something at them? Or would they zap them with Reagan's beloved lasers? These days, laser weapons do exist, but they require enormous energy and weigh a lot; typically, they are installed on warships. Says Hellyer: 'It's been really hard to get them to work even against fairly traditional threats like cruise missiles or drones.'
Star Wars offers some lessons (the real one, not the film). Many of Edward Teller's claims to Reagan about the prospects of satellites firing lasers made from concentrated X-rays, particle beams and 'microwave devices' were highly exaggerated, says William J. Broad, author of the 1992 exposé Teller's War, and rarely performed as hoped in tests. The popular notion of a giant space station permanently parked above a rogue state that can shoot death rays on command is, thanks to the laws of orbital physics, probably an impossibility. To park it in a geostationary orbit, it would end up 35,000 kilometres away from Earth, which would put its ability to rain down lasers that have enough power to cause damage into the realm of science-fiction.
Washington consulting firm Booz Allen Hamilton is instead advocating for a reboot of a curious idea that emerged out of Star Wars research called Brilliant Pebbles. A relatively low-tech scheme (at least, compared with lasers), it would deploy swarms of numerous small interceptors into a low-Earth orbit (2000 kilometres or lower altitude), to collide with enemy missiles as they speed past, their great numbers ensuring there are always enough passing over an enemy's territory to be able to intercept missiles in time.
So, what's the catch?
One would not imagine Russia or China sitting idly by while the US floods their skies with rocket-killing satellites, potentially depriving them of the capacity to respond to a nuclear strike. Both nations – and North Korea – have already condemned Trump's plan as destabilising. 'You could argue that all it does is kind of foster miscalculation,' Hellyer says.
Then there are the inevitable countermeasures to overwhelm the anti-missile missiles (the anti-anti-missiles, perhaps) and space defences. 'All defensive systems can be defeated by countermeasures that cost far less,' wrote Charles Bennett of The New York Times in 1989 when Brilliant Pebbles was first proposed. 'The reason for that is simple. It's a lot easier to hit an orbiting satellite than a warhead moving at a vast rate of speed. Moreover, it's also easy to build enough new missiles to numerically overwhelm a defence, or to develop missiles that get into space before interceptors can target them.' Tellingly, the last remaining bilateral arms control treaty between the United States and Russia (the New Strategic Arms Reduction Treaty, or New START, which limits the number of long-range nuclear weapons) could expire early next year if not extended, opening the door to another arms race.
China is believed to have been developing space-based weapons to disable satellites, Bri­gadier Gen­eral Shawn Brat­ton, deputy dir­ector of oper­a­tions at US Space Com­mand in Col­or­ado, said in 2020. Russia has also been considering sci-fi weapons of its own, says RUSI's Sidharth Kaushal, in the form of nuclear-powered jammers (or signal-blockers) and space-based plasma guns.
Then there's the money. Star Wars was already on the nose with Congress by 1987, when doubts grew about its promised capability and Reagan continually asked for more funding. Republican senator Jim Coulter warned that the program would be 'bled to death' by budget cuts unless it could demonstrate at least some defences that could be deployed in a few years. 'I think it's just impossible to sustain a vague defence research goal,' he said presciently. The Congressional Budget Office this year estimated that even a skeleton deployment of what it calls 'space-based interceptors' would probably blow the entire Golden Dome budget, costing between $US161 billion ($250 billion) and $US542 billion ($840 billion).
The US is also facing a bill in the billions to upgrade its existing nuclear deterrent, Hellyer says. While upgrading the existing Virginia class submarines to nuclear capability will shoulder some of the load, 'The US is facing a situation where it could be spending itself into irrelevance. It'll have an offensive system that's massively undercapitalised and obsolete and isn't the deterrent that it wants it to be. Meanwhile, it'll have this kind of half-baked defensive system that isn't really a deterrent either because any adversary will look at it and go, 'Well, it can't really stop us getting through'. It's the worst of both worlds.'
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Malcolm Davis says: 'I think what you will end up with is a leaky shield that makes it more difficult for an adversary to get an attack through, and can certainly defend against limited attacks, but it will never be something that will make it impossible for the Russians or the Chinese to attack the United States.'
Pavel Podvig, a senior researcher at the United Nations Institute for Disarmament Research, told The Wall Street Journal: 'This missile-defence mirage gives you the illusion you can protect yourself, but you're driving all these countries to build all these hundreds and thousands of missiles.' Says Hellyer: 'What's a satisfactory success rate? Let's say the bad guys launch 100 missiles at you with 1000 warheads. Let's say you have a 90 per cent success rate. Well, that's still 100 getting through.'