Part of daring plan to pulverize Earth-bound asteroid

It’s typical of the movies: an asteroid is on a collision course with Earth, and we must do something to stop it or die.

It is disturbing that this scenario is also that of the real universe. Scientists have discovered more than 2,000 “potentially dangerous” asteroids. To earn this official designation from NASA, an object must be at least 460 feet in diameter and have an orbit that passes approximately 4.7 million miles from our planet.

Protect the Earth These rock hazards fall under an area called “planetary defense.” A group of researchers at the University of California, Santa Barbara, has a deceptively simple idea for how to take care of such an asteroid: pulverize it.

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“Pulverize It” is actually the name of the project proposed by the group. planetary defense program. It’s a pretty accurate nickname: Scientists have designed a system that would break almost any asteroid into ineffective pieces using already developed rockets and projectiles. It can deploy in response to a large or small warning delay. “We currently have the technology to build a planetary defense system,” says Philip Lubin, a professor at UC Santa Barbara and principal investigator on the project. But we didn’t do it.

Asteroid assault

Historically, planetary defense research has focused on deflecting asteroids by using their momentum to push their cosmic trajectory away from Earth. It is what NASA did with its Double Asteroid Redirection Test (DART) spacecraft, which collided with the lunar asteroid Dimorphos in September 2022 and changed its orbit, to show that this was possible.

But this relatively mild type of defense only works if scientists discover dangerous asteroids well in advance (and the greater the threat, the longer the warning time generally needs to be). A space rock might only be detectable when it gets so close to Earth that we no longer have time to divert it from its dangerous path.

Another limitation of deflection is that an asteroid must be small enough that hitting it sufficiently changes its trajectory, says Sasha Cohen, a researcher at UC Santa Barbara who is working on Pulverize It. After all, you can’t force a semi into the right lane by rolling your bike into it.

Spray It takes a different approach. The team does not intend to push dangerous asteroids into collision-free orbits, but rather to divide them into many small parts, as is done in the classic arcade game aptly named Asteroids.

To do this, Lubin and his colleagues propose starting from an existing and proven rocket, such as SpaceX’s Falcon 9, which has been successfully launched 165 times in 2025.

The rocket would carry “penetrators” or projectiles that would shatter the asteroid. This could be passive tungsten bullets in the case of small asteroidal enemies or a nuclear explosive, launched into a hole pierced by the tungsten bullets, if the threat was more formidable.

“It’s a kind of global method of planetary defense that can cover almost all types of threats,” Lubin explains. The nuclear option is complicated, however, because many countries, including the United States, have technically agreed not to detonate or position nuclear weapons in space.

However, political complications concern decision-makers; Lubin says these salaries exceed the group’s salary level. Lubin’s team is interested in physics and engineering. What would it take to pulverize an asteroid? This is part of the work Cohen has been working on: running simulations on NASA supercomputers, with support from the NASA Innovative Advanced Concepts program, to study the mass and speed needed for a penetrator to shatter asteroids of different sizes and with different warning times.

These calculations, however, call for others: Pulverizing This would not turn an asteroid into dust, just smaller pieces. These fragments could hit Earth, especially if the warning time is short and the asteroid is already close. So can the team ensure that the pulverized pieces are small enough to not pose their own danger?

This is where the work of Cohen and Lubin’s colleague Brin Bailey, a research scientist at UC Santa Barbara, comes into play. The goal of the program is to pulverize such an asteroid into pieces ideally about 13 to 16 feet in diameter (but no more than about 50) so that they burn up when they enter Earth’s atmosphere. This would mean, ideally, no one would get their heads hit.

But even the interaction between the atmosphere and the asteroid pieces as they burn and burst could be dangerous if the asteroid is disrupted when it is close to Earth. “Each burst will produce an acoustic shockwave as well as an optical flash,” says Bailey, “so bright light, little sound.” Scientists must plan to minimize these effects, they add, to avoid breaking windows or starting fires. This simulation work is facilitated by a GPU donated by NVIDIA.

If we ever used a nuclear explosive to shred an asteroid, the resulting fragments would be radioactive. That’s why Bailey’s work also simulates the potential radiological effects resulting from pulverizing an asteroid to ensure that any pieces falling from space wouldn’t expose people to dangerous levels of radiation. These terrestrial studies suggest that Earth’s atmosphere can efficiently distribute the energy of almost any asteroid, preventing it from destroying flora and fauna on the ground.

Take action

Pulverize It is not an official planetary defense program. It’s just a potential plan. There is in fact no fully operational mitigation strategy for dealing with a potentially dangerous asteroid. The field of planetary defense exists largely within the realm of scientific study; in the United States, this involves NASA research.

Lubin advocates for turning this research into action. Whoever is leading this effort is, once again, he says, above his pay grade. But some experts, including Peter Garretson, a former Air Force strategist and current member of the U.S. Foreign Policy Council, have advocated putting that responsibility in the Defense Department. In fact, Lubin is positioning Pulverize It as a potential addition to the Golden Dome framework, President Donald Trump’s missile defense plan. After all, Pulverize It is similar to a missile defense program: both aim to find a bullet speeding through the sky and shoot it down with a different type of bullet. Most scientists doubt the viability of the Golden Dome, which relies on technology the United States does not yet possess, but Lubin hopes the alignment of projects could garner support for planetary defense.

If Lubin can take this idea from academia to action, he would like to see the Pulverize It system perpetually ready to launch rather than having to wait for a dangerous asteroid to approach and be detected before a response plan is created. The current strategy is more like “let’s wait until a threat presents itself, then we’ll have a group meeting and decide what to do,” Lubin says.

Whatever the ultimate “thing to do” – spray or otherwise – it’s probably better to be prepared rather than scrambling to avoid getting bludgeoned.