X-ray Pulses from Nuclear Explosions Can Deflect Dangerous Asteroids, Researchers Say

Around 66 million years ago, the Chicxulub asteroid impact triggered mass extinction, mega-tsunamis and a spell of global warming that lasted for around 100,000 years. Although NASA’s Double Asteroid Redirection Test (DART) mission demonstrated that near-Earth objects can be successfully targeted, deflecting the most dangerous asteroids will require energy concentrations akin to nuclear explosions. However, targets suitable for practice missions are scarce. Scientists have now demonstrated the simulation of asteroid deflection with an X-ray pulse from dense argon plasma generated at the Z machine, a pulsed power device at Sandia National Laboratories.

Comets and asteroids can pose a threat to our planet if their trajectories come too close to Earth.

As demonstrated recently by NASA’s Double Asteroid Redirection Test (DART) mission, a spacecraft can be used to hit and change the path of an asteroid.

However, this physical impact approach requires ample time and preparation and is generally expensive.

In an alternative approach, X-rays from a nuclear explosion could be used to rapidly heat the targeted object’s surface, causing it to vaporize and change its direction of motion.

Sandia National Laboratories researcher Nathan Moore and his colleagues tested how to mimic the effect of a nuclear device impacting an asteroid in laboratory experiments.

They used X-rays to target two 12-mm-wide mock-up asteroids in a vacuum — one sample consisted of quartz, while the other was made from fused silica.

In both experiments, the authors observed the X-ray pulses heating up the surface of the asteroid analogues, resulting in a vapor plume that generated transferred momentum to the quartz and silica targets and generated velocities of about 69.5 m per second and 70.3 m per second, respectively.

They then used these measurements to conduct numerical simulations on how this method of asteroid deflection could scale and suggest that near-Earth objects with a diameter of around 4 km could be deflected with the nuclear impactor strategy.

They suggest that future experiments could investigate other target materials and structures and test different X-ray pulses, as the vapor plume generated by the X-ray pulses is dependent on the chemical composition of the asteroid.

“We scale these results to proposed interceptor energies and predict that asteroids up to a diameter of 4 km can be deflected with this mechanism, showing a viable way to prepare for future planetary defense missions,” they said.

The results were published this week in the journal Nature Physics.

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N.W. Moore et al. Simulation of asteroid deflection with a megajoule-class X-ray pulse. Nat. Phys, published online September 23, 2024; doi: 10.1038/s41567-024-02633-7