In 1982, President Ronald Reagan was considering what became known as “Star Wars,” a plan to protect America from Soviet missiles by deploying up to thousands of weapons in space. At the same time, as a young science writer, I was talking about how the rays from a nuclear explosion in orbit could wipe out entire fleets of battle stations and laser death beams. “Star Wars: Pentagon Lunacy,” read one of the headlines.
Decades later, Mr. Reagan and the Soviet Union are gone, but anxiety about a high-altitude nuclear explosion remains alive, reignited more recently by the ostensible war aims of Russian President Vladimir V. Putin. Last month, US intelligence agencies told Congress, as well as foreign allies, that Mr Putin might develop and use an atomic bomb in space that could disable thousands of satellites. Not only military and civilian communications links would be at risk, but also satellites that spy, monitor the weather, emit radiation, enhance cell phone maps, establish Internet connections and perform dozens of other modern tasks.
The mere allegation of such a development may help Mr. Putin intimidate his opponents.
“Its purpose is the same as Star Wars for us in the ’80s,” said Jonathan McDowell, an astrophysicist who publishes a monthly space report. “It’s to scare the other side.”
But to actually fight a war, analysts say, the step is hard to imagine – unless Mr Putin wants some of his most important allies and supporters to face the prospect of untold pain.
Five nuclear experts in a 2010 study explained how astronauts hit by the most powerful rays would experience two to three hours of nausea and vomiting before radiation sickness left them with a “90 percent chance of death.”
The International Space Station is normally home to seven astronauts – three Americans, one foreigner and – you guessed it – three Russians. The radiation could also turn the space station of Mr. Putin’s top ally, China, into a death trap. Beijing’s shiny new outpost is currently home to three Chinese astronauts and is set to expand to accommodate even more.
China’s satellites — 628 at last count — would be an additional vulnerability. Stephen M. Younger, the former director of Sandia National Laboratories, which helps build the country’s nuclear weapons, said in an interview that a Russian space explosion could blind China’s reconnaissance satellites and thus end the country’s primary means of surveillance of the US Navy in the Pacific.
“This is not going to go very well,” said Dr. Younger about losing his eyes in the sky from Peking in wartime.
Mr. Putin’s alleged bombing move, he added, represented more of an abomination than a serious war plan. “Putin is not stupid,” he said.
The whole idea behind nuclear weapons, said David Wright, a nuclear expert at the Massachusetts Institute of Technology, is that “you are deterred in part because the weapons would cause significant collateral damage to yourself and other countries.” That deterrence could also apply to a space bomb, he added, unless an attacker was desperate and deemed the risks acceptable.
“It would be dangerous for the Russians themselves,” said Richard L. Garwin, a physicist and longtime adviser to the federal government who helped design the world’s first hydrogen bomb.
Since Mr. Putin invaded Ukraine, he has issued individual threats that analysts see as central to his strategy to deter Western intervention. If it put an atomic bomb into orbit, it would violate two fundamental treaties of the nuclear age – signed in 1963 and 1967 – and would mean a major escalation.
On February 20, Mr Putin denied that he intended to send a nuclear weapon into orbit. “Our position is clear,” he said. “We have always been categorically opposed and now we are against the development of nuclear weapons in space.”
But days later, on February 29, in his annual State of the Nation address, he returned to his usual rattle, warning that the West was facing the risk of nuclear war. Mr Putin singled out the states that helped Kiev strike Russian soil. The West must understand, he said, that such aid risks “the destruction of civilization.”
Nuclear weapons in general, and space bombs in particular, are the antithesis of precision. They are indiscriminate — unlike conventional weapons, which are usually characterized by pinpoint accuracy. In 1981, when I first wrote about orbital nuclear weapons as a reporter for Science magazine, I referred to the chaos from space as the “Chaos Factor.”
The unexpected phenomenon came to life in July 1962 when the United States detonated a hydrogen bomb about 250 miles above the Pacific Ocean. The dark skies brightened. The street lights went out in Hawaii. In orbit, the satellites failed.
President John F. Kennedy, alarmed by technical surprises, worried that prolonged radiation from nuclear explosions would endanger the astronauts. In September 1962, he canceled a test codenamed Urraca. The hydrogen bomb was to have been detonated at an altitude of more than 800 miles – the highest of any test explosion, American or Soviet. The following year, Mr. Kennedy signed a treaty banning experimental explosions in space.
The scientific world then made an important distinction about space explosions that is absent from most current discussions. It is that atomic explosions have immediate, but also residual, effects.
The initial effects are better known. A bomb’s rays are accelerated over vast distances to produce lightning strikes on satellites and ground networks, which fry electrical circuits. Experts call them electromagnetic pulses or EMPs. The pulses knocked out the lights in Hawaii.
But what caught Mr Kennedy’s attention was a long-term effect – how radioactive debris and charged particles from a nuclear explosion pump out the natural doughnut-like radiation belts that encircle the Earth. These bands are intense, but nothing like what they become when enhanced by the radiation of a bomb.
The five nuclear experts who authored the 2010 study linked such belt overload not only to risks to astronauts but also, after the July 1962 test, to extensive damage to at least eight satellites. The most famous victim was Telstar, the world’s first communications satellite.
Over the years, I worried that the complex subject was being oversimplified. Fringe groups and hawkish politicians sounded the alarm about Russian EMP attacks on the country’s power grid, though they rarely noted the danger to Moscow’s spacecraft and astronauts.
Peter Vincent Pry, a former CIA officer, warned in a 2017 report that Moscow was prepared for surprise EMP attacks that would paralyze the United States and destroy its satellites.
In 2019, President Trump ordered the strengthening of the nation’s EMP defenses. Rick Perry, the energy secretary, said the order “sends a clear message to adversaries that the United States takes this threat seriously.”
National security experts know how weapons of mass destruction are caught in cycles of fear that come and go with the political winds. After decades of pondering the basics of nuclear explosions in space, I’ve come to view the risks as extremely low to non-existent because an explosion—like Dr. McDowell, Younger, Wright, Garwin and others have argued – it would hurt not only the aggressor, but also the aggressor.
“Maybe the Russians will decide that their astronauts should take one home,” Dr McDowell said. “But I think Putin, as crazy as he is, is not going to do that.”
