THE RACE TO PREVENT SATELLITE ARMAGEDDON / THE ECONOMIST

High alert on high

The race to prevent satellite Armageddon

Fears of a Russian nuclear weapon in orbit are inspiring new protective tech

In early 2021 Micross Components, a designer of highly specialised circuitry in Melville, New York, received an intriguing request. 

An American aerospace giant wanted components that could protect a military system’s electronics from the radiation generated by a nuclear detonation.

Micross signed the contract, and set about doing the work, but was left in the dark about why such a system would be needed. 

The puzzle pieces fell into place earlier this year, says Mike Glass, a product manager at Micross, when American officials began to talk about Russian plans to place a nuclear weapon in space.

That talk was motivated by a Russian satellite called Cosmos-2553, which is thought to be secretly testing the necessary electronics some 2,000km above Earth’s surface. 

A nuclear detonation there would probably be too high to wreak any meaningful direct damage on the surface of Earth. 

But it could cause what Lieutenant-Colonel James McCue, an outgoing official with America’s Defence Threat Reduction Agency, calls a “satellite Armageddon”. 

Many of the nearby spacecraft tightly packed in lower orbits would be immediately fried; a greater number farther afield would slowly succumb to the radioactive aftermath. 

The blast would affect all countries’ satellites indiscriminately.

Terrestrial catastrophes would swiftly follow. 

Satellites do more than relay communications and survey the planet. 

They also provide critical geolocation and timing signals used in transport, financial transactions and infrastructure such as electric grids and mobile-phone networks. 

Victoria Samson, head of space security at the Secure World Foundation, an American research outfit, says a big technological push is on to mitigate the risk.

In the vacuum of space, a nuclear detonation does not generate a ball of fire or a blast wave. 

It does, however, create a surge of radiation and charged particles known as an electromagnetic pulse (emp), which can disrupt electrical circuitry. 

In 1962 the emp from an infamous American nuclear test called Starfish Prime disabled a third of all satellites then in orbit (though some took months to succumb). 

The detonation, which took place at an altitude of about 400km, also disrupted electrical equipment on the ground in Hawaii. 

The following year such tests were banned by an international treaty.

Strictly speaking, it is not the emp itself that ruins circuitry. 

Rather, the radiation and excited particles switch on microchip transistors all at once, and the resulting voltage surge from the hardware’s power supply does the frying. 

This means that if a satellite’s power can be shut down before the brunt of an emp arrives, the system may well survive. 

Devices designed to do just this were first made during the cold war, but few companies have carried on building them. 

Space nukes were “supposed to be off the table”, so investing in protection wasn’t a priority, explains Colonel McCue. 

The assumption that no one would be reckless enough to park a nuclear weapon in orbit, he says, no longer holds.

The defence firm that got in touch with Micross sought a much better “nuclear-event detector” (ned), as these microchip assemblies are known. 

Micross says it has succeeded. 

On April 8th it announced a new line of neds that are now in final testing. 

The devices shave up to 40 nanoseconds off the response time of earlier models. 

Their new ned series has a uniquely ungainly name: myxrhnedhcj. 

The devices detect the initial build-up of gamma rays produced by a nuclear detonation in 15 nanoseconds flat, before the radiation has risen to dangerous levels. 

The devices immediately fire off what John Santini, the firm’s chief technologist, calls a “here it comes” signal that shuts down power across the hardware’s circuitry. 

Once the emp subsides less than a second later, the devices send a command to restore power.

Concerns over Russia’s nuclear intentions in space have fuelled a jump in demand for neds that has surprised even Micross. 

Such gizmos are not cheap. 

Equipping America’s gps satellites with neds has increased their total cost by about 1-2%. 

The same would be true for any other big spacecraft, largely because making the necessary changes to the satellite’s circuitry can take a handful of engineers half a year. 

Equipping smaller satellites, which are typically flown in low Earth orbit, at altitudes below 2,000km, raises their total cost by a higher percentage.

Small satellites have, therefore, rarely been protected with neds. 

This may change as rising demand lowers costs. 

Though Mr Santini declines to name customers, he says it’s fair to assume that the myxrhnedhcj series will be put in future military satellites for low Earth orbit. 

Micross is now fielding inquiries for detectors to protect ground vehicles. 

Fears of Russian tactical nuclear-weapons use in Ukraine might be inspiring such precautions.

Surviving an emp is a good start, but not enough. 

Discharging a nuke in space fills regions around Earth with radiation and energetic particles that can zip around the planet for months before subsiding. 

A big detonation could contaminate areas with three and possibly even four orders of magnitude more radiation than background levels. 

Speaking at a space conference in Colorado Springs in April, Heidi Shyu, the Pentagon’s top engineering officer, urged companies to develop better radiation protections for spacecraft.

This is not easy. 

As circuitry got faster and smaller, it has generally become more delicate. 

The energy deposited by incoming radiation, for example, can rewrite individual bits of memory. 

The problem is worsening as chipmakers continue to develop new technologies. 

Daniel Loveless, an engineer at Indiana University, Bloomington, specialising in the radiation-hardening of electronics, laments that the field is “at the whim” of chip innovations that render previous protections obsolete.

Hardening advances are nonetheless being achieved. 

One method is to reconfigure circuitry to reduce wiring. Conductive wires are prone to storing bits of energy. 

When exposed to radiation, this energy can cause malfunctions. 

To shorten wires, Apogee Semiconductor, a Texas firm that hardens electronics for space, arranges chips in stacks rather than side by side, and feeds wire through thin plastic encasements rather than bulky ceramic ones (any subsequent loss of protection can be rectified by additional layers of lead shielding).

Exactly how well such defences would weather a nuclear detonation is unknown. 

Satellites that do remain operational, however, would face another problem—heavy radiation can interfere with radio signals. 

A project led by darpa, a Pentagon research arm, could help. 

Called the Space-Based Adaptive Communications Node, it aims to use lasers to ferry data between satellites. 

This would facilitate handoffs to get urgent data, such as a target’s co-ordinates, to a ground station sooner. 

Crucially, a laser’s high frequency also renders it far less vulnerable to radiation.

But what if the threat itself could be neutralised? 

A nuclear weapon launched from Earth’s surface and detonated in space would be hard to stop. 

But an armed satellite already in orbit could potentially be disabled or jammed—if it could be identified in the first place. 

With today’s roughly 10,000 active satellites likely to be joined by many thousands more in the next few years, detecting such a threat is getting ever harder. 

darpa reckons artificial intelligence (ai) will help.

Slingshot Aerospace, a company based in California, has used funding from darpa to develop ai that can single out potentially nefarious satellites. 

Slingshot operates a network of telescopes and other sensors that collect data on the position, behaviour and appearance of satellites from more than 20 stations worldwide. 

This is augmented with data from the Department of Defence, satellite manufacturers, and even online posts about activity in space. 

The information gives Slingshot’s algorithms lots of dots to connect.

Some conclusions would be straightforward enough. 

A satellite with a nuke, for example, would probably be heavy, requiring more small manoeuvres than average to remain in orbit. 

An armed satellite might also contain different metals from its neighbours, potentially giving it a distinctive brightness. 

Fluctuations in reflectivity can also reveal changes in orientation, perhaps because a satellite is extending a grappling arm or aiming a laser or pellet gun. 

The frequency with which the satellite transmits data back to Earth, and the countries over which such data transfer occurs, provide additional clues.

The software also forecasts behaviour. 

Audrey Schaffer, Slingshot’s vp of strategy and a former head of space policy on America’s National Security Council, gives the example of a Russian spy satellite called Luch-2, whose movements have been correctly predicted by a Slingshot ai model called scope. 

Slingshot describes it as a “neighbourhood watch” for space. 

Such eyes on the sky are welcome. Charles Galbreath, a colonel in America’s Space Force until his retirement at the end of 2022, says a nuke in orbit would be like a “gun to our head”. 

One hopes the accuracy of the analogy need never be tested.