by In 1962, the US conducted the largest nuclear test in outer space. The effects were far more devastating than the Pentagon imagined and created a treaty that prohibited the deployment of nuclear weapons in space.
In the test, called Starfish Prime, a 1.4 megaton nuclear weapon was detonated 250 miles above the Earth’s surface in the Pacific Ocean.
In an instant, an electromagnetic pulse – a brief burst of energy – struck hundreds of street lights in Hawaii, about 900 miles away.
But the most powerful effects were felt in space. Within minutes, the explosion created a fireball and a glowing red aurora clearly visible to observers hundreds of miles below.
Unexpectedly, energetic electrons released during the high-altitude nuclear explosion became trapped by the Earth’s magnetic field, forming radiation belts that lasted for several months after the detonation. As they traveled around the planet, they destroyed or damaged a third of all satellites in low orbit at the time, including some located on the other side of the earth. Among those damaged was the UK’s first orbital satellite, Ariel One.
It is this experience in part that has fueled the alarm at reports that Russia is developing a new space-based anti-satellite (ASAT) weapon. Although people with knowledge of the classified information say the weapon system is still under development and has not been deployed in orbit, it is said to include a nuclear component.
The exact nature of this nuclear component remains uncertain. Two prevailing theories suggest that Russia is developing a nuclear-armed or nuclear-powered ASAT capability.
The prospect of a nuclear-armed anti-satellite weapon raises questions about what exactly it might be used for militarily. Russia has demonstrated in the past that it is capable of conducting conventional strikes against satellites. In November 2021, Moscow was widely criticized for conducting a routine ASAT test that produced so much space debris that it posed a temporary threat to the International Space Station.
In theory, detonating a nuclear weapon in space could have the advantage of rapidly disabling a large number of escort satellites in one decisive blow. This is because the electromagnetic pulse (EMP) produced as a by-effect of a nuclear detonation can permanently disable electrical and electronic equipment over a relatively large area, especially if the nuclear device is detonated at high altitude.
Although satellites can be hardened to withstand the bombardment of charged particles released during high-altitude nuclear detonations, only a relatively small proportion of military-grade satellites currently in orbit have undergone such hardening measures. The vast majority of commercial satellites in low Earth orbit, which are vital for economic activities, incorporate standard electronics in their payloads that make them vulnerable to attacks of this type, making Western states vulnerable to attacks of this kind this type.
The second option, deploying a nuclear-powered ASAT weapon that uses lasers or particle beams to destroy its targets, could, in theory, have the same benefits, while avoiding some of the associated risks. This approach could allow Russia to threaten larger constellations of microsatellites, such as those that make up Elon Musk’s Starlink internet system, without generating excessive space debris and radiation, and the self-harming effects nuclear detonation could be avoided.
The Soviet Union and its successor states are known to have worked on nuclear-powered “space thugs” that could theoretically be equipped with electronic warfare capabilities, including electromagnetic energy weapons that could be effective against satellites. However, it remains uncertain whether Russia had the capacity to invest in such technology after two years of high-intensity ground warfare in Ukraine and a tough sanctions regime that continues to undermine its technological base .
This suggests that while Russia may have the capability to deploy a space-based nuclear warhead in the not-so-distant future, deploying a sophisticated nuclear-powered electromagnetic weapon system in the space.
Regardless, if an active weapon system were to be used in space, it would be a major aggravation and a clear violation of the 1967 Outer Space Treaty, to which Russia is a signatory.
The revelation also highlights Russia’s continued willingness to disrupt and destabilize the political environment in order to achieve perceived advantages. With a space-based and potentially nuclear ASAT weapon, Moscow would have the option of launching a devastating attack on NATO at any moment – a significant piece of leverage that could prevent the bloc from reacting decisively against a ground attack on an alliance member.
That, however realistic, could be the threat that Vladimir Putin hopes to hang over the heads of the West.
Fabian Hoffman is a doctoral research fellow at the Oslo Nuclear Project.
