Space nukes: The unbelievably bad idea that's exactly that ... unbelievable

Opinion Space nukes. You're kidding, right? Not if scary reports for last week are true, and Russia is indeed reviving some of the Cold War's more ominous ideas. What's more, Russian leadership is denying it all, and you know what those guys are like.

The implication was that Russia was planning to orbit nuclear weapons designed to take out large numbers of enemy satellites. As the West is completely dependent on satellites for communication, guidance, information gathering, and waging war, this is a pretty scary threat. It is also stark raving bonkers. Let us count the ways.

First, developing, deploying, and testing such weapons is illegal under international law. Treaties may be the last thing on the mind of a state intent on throwing nukes about. Breaking those treaties means the other lot aren't bound by them either, though, and if the other lot has a much more advanced space capability, that may not pan out so well. 

Then there's the reason those treaties exist – space nukes work, and work all too well. You can build all sorts of conventional anti-satellite weapons that can hobble hardware you don't like. Everyone's had a go at this on the grounds that if the bad guys can put something nasty up there, the good guys can put up something nastier to stop it.

Killer satellites loitering about until needed turns out to be a poor idea. Orbital mechanics make it hard, slow, and expensive to maneuver one orbiting thing close to another, especially if that other isn't keen to cooperate. It's better to launch on demand from the ground or an aircraft, both of which have the added benefit over orbiting assets that they're not floating around in space in a known orbit for the enemy to see 24/7.  Satellites aren't hardy – a small explosion generally suffices to put them off their stroke.

True, a nuke doesn't need to get very close to things to have the same effect. That's their biggest problem – they'll fry anything in range regardless of brand. The space-capable nation that can deploy a killer space nuke will have its own vital war and peace infrastructure up there too. As an act of random violence against every country on the planet, space nukes make sense. In any other case, they redefine insanity. Option one hundred on a list that stops at ten.

We know this because we've tried it. You may recall Telstar, the world's first communications satellite. Sent aloft in 1962, it was a happy, shiny beach ball of a satellite that carried the world's first live transatlantic TV transmissions, it had a happy, shiny song named after it. It was all-American. It got fried by an all-American space nuke called Starfish Prime.

Starfish Prime was a megaton-range nuclear detonation 400 km above the Pacific, just to see what happens when you set off huge space nukes. Yes, that was as sophisticated as it got. The result was an unexpectedly vast number of very high-speed electrons, which as well as being massively toasty radiation in their own right also did what electrons do when you give them an enormous shove – they generate an enormous pulse of radio waves.

This was the discovery of EMP, the electromagnetic pulse typical of space nukes. This one disrupted electrical systems in Hawaii some 1,000 km away. What else it did is less clear as the test results are still classified. Worries about EMP resurface occasionally, with nervous preppers keeping their spare shortwave radios in biscuit tin Faraday cages. It  wasn't the EMP that got Telstar, which launched the day after Starfish Prime, but those pesky high-speed electrons that hung around for a few months thanks to the Earth's magnetic field and pickled Telstar's transistors over the next few months.

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None of this was in any way controllable and the Soviets, who'd been having a go themselves, soon asked for a moratorium on the whole business – a moratorium that, like the laws of physics that inspired it, still stands. It's not as if we haven't got more dependent on sensitive electronics since.

Whatever is behind the Russian space nuke scare, it's not sky bombs. Which leaves nuclear reactors in space. This may not seem much better, but hold your horses. Many of your favorite space missions have used space nuke power – Cassini, the Voyagers, Curiosity and Perseverance on Mars. Even Apollos 12 to 17 had small nuclear power plants to keep science experiments going after the astronauts had taken their giant leaps back home. If solar power won't fly your mission, go for fission.

Thing is, solar power is very good these days. Galileo, the '80s Jupiter mission, used a nuclear power source because it was so far from the Sun. Juno, the mission out there now, is fine with solar. Nuclear power isn't needed in Earth orbit, which is just as well as while it's a great technology, it's even better when it's attached to something that is never, ever coming back down. So why would Russia need it?

The sanest guess is electronic warfare, an aspect of which is stuffing so much unwanted energy into the radio spectrum your enemy is trying to use that signals are spoofed or jammed. A space platform with lots of watts to hand would theoretically be quite useful, both against other space assets and ground-based systems. Indeed, Russia is known to have such a project, Ekipazh, which is indeed powered by a nuclear reactor. If there is a potential nuclear threat in space, it's probably this.

Even this is an odd candidate. First proposed in 2010, it has been known about and discussed by Western analysts since 2018. It has the same problem as other space-based weapons in that it's a tempting and very visible target itself, while chucking out kilowatts of signals at frequencies you can't form into very tight beams is going to annoy more than just your intended victim. Expensive, inflexible, vulnerable, and difficult to operate and maintain, especially if you don't have the best track record in top-notch tech, it's by no means a slam-dunk idea.

What it is good at, though, is scaring people. If you're a Putin supporter, you might hope it distracts and dismays the warriors on the other side. If you're American – let's say, someone trying to get a big aid package through to Ukraine – you might hope it scares some of the people who are trying to stop that happening. And if you're a news outlet, you'll just appreciate the traffic that big headlines about space nukes can bring. Where the truth lies, dear reader, is up to you to decide. One thing's for sure – you're safe enough keeping your smartphone out of the biscuit tin. ®