Asteroid Shape Complicates Nuclear Deflection Plans, New Model Finds

WHO:

The Register - Sandia National Laboratories staff physicist Nathan Moore led the research team.

The Register - The simulations modeled three asteroids: Golevka, Bennu, and Itokawa.

Phys.org - The article describes a nuclear detonation as one possible defense against a dangerous asteroid headed toward Earth.

WHAT:

The Register - Sandia researchers developed a faster, more detailed method for modeling how X-rays from a nuclear detonation near an asteroid could change its trajectory.

The Register - The combined modeling approach is more than 1,600 times faster than earlier methods, while retaining sufficient accuracy to predict deflection in irregularly shaped asteroids.

The Register - Simulations found that irradiating different sides of the same asteroid could produce as much as a fivefold difference in resulting velocity change.

The Register - Bennu, described as the most symmetrical of the three modeled asteroids, showed nearly twofold differences in deflection velocity depending on which side faced the blast.

The Register - Moore said, “We expected aim to matter. What surprised us was how much.”

Phys.org - New simulations indicate that the precise location where X-rays hit a lumpy, irregular asteroid could greatly affect the resulting deflection.

WHERE:

The Register - The research was conducted at Sandia National Laboratories.

Phys.org - The hypothetical asteroid is described as headed toward Earth.

WHY:

The Register - Earlier calculations were so time-consuming that researchers could not readily explore many scenarios, asteroids, or mission concepts.

The Register - Irregular asteroid shapes complicate predictions of nuclear deflection; accurate predictions also depend on knowing an asteroid’s composition and internal structure.

Phys.org - A nuclear detonation could use X-rays to blast one side of a dangerous asteroid and nudge it off course.

HOW:

The Register - The team combined Sandia’s ALEGRA and SPARTA simulation codes. ALEGRA models radiation heating and high-energy material dynamics and handles high-gas-density regions; SPARTA simulates low-density gases and handles more dilute regions.

The Register - ALEGRA can accurately simulate vaporization of rocky surfaces but becomes less efficient at low densities; SPARTA is more efficient at low gas densities but becomes harder to run at high densities.

The Register - Earlier simulations often represented asteroids as spheres to reduce calculation time, although perfectly spherical asteroids are rare.

Phys.org - The proposed defense mechanism is a nearby nuclear detonation that sends X-rays toward one side of the asteroid.

(UPDATED November 4, 2026 10:03 UTC)

Sandia researchers created asteroid-defense simulations more than 1,600 times faster than earlier methods. They found where X-rays strike an asteroid can change its deflection substantially. The findings could help assess nuclear blasts as a way to divert dangerous asteroids.