Researchers in China have modeled the optimal approach for using a nuclear device to deflect an asteroid heading toward Earth. The study, published by a team at the China Academy of Space Technology, compared two primary deflection methods: a stand-off detonation and a surface burst. Their findings identify the precise timing and positioning needed to maximize momentum transfer without fragmenting the target.
The stand-off method — detonating the warhead at a distance from the asteroid — proved more effective in simulations, as it avoids breaking the rock into multiple potentially dangerous pieces. A surface burst, by contrast, risks scattering debris that could still threaten the planet. The team calculated that a yield of around one megaton would be sufficient for an asteroid up to 100 meters wide, though exact numbers depend on composition and trajectory.
No immediate threat has been identified, but the research is part of broader global preparedness efforts. NASA's Double Asteroid Redirection Test (DART) successfully demonstrated kinetic impact deflection in 2022, yet nuclear options remain a backup for larger or shorter-warning scenarios. The Chinese study specifically focused on scenarios with less than five years of warning time.
The paper was published in the journal Icarus and marks one of the few detailed Chinese contributions to planetary defense modeling. It follows a 2023 report by China's National Space Administration outlining a multi-phase asteroid defense roadmap, including a planned kinetic impact test by 2030.
Critics argue that nuclear deflection carries significant political and environmental risks, including the potential for weapons use in space. Some experts note that actual asteroid materials may behave unpredictably, reducing model accuracy. Nonetheless, the study adds valuable data to an evolving field that has seen increased international collaboration since DART's success.