A scientist warned that NASA’s drastic planetary defense strategy against an asteroid impact may not work as planned. According to the scientist, it could even cause multiple asteroid impacts on Earth.

Currently, NASA’s main defense against an approaching asteroid is by launching a spacecraft and intentionally colliding it with the space rock to deflect it. However, if the asteroid is already too close to Earth, deflecting it may not work. In this kind of scenario, NASA plans to use a kinetic impactor to destroy the asteroid.

This strategy works by equipping a nuclear device with a kinetic impactor tip. The main role of the impactor is to detonate on the surface of the asteroid in order to create a crater. The nuclear device will then explode within the crater. Ideally, the shockwaves from the nuclear device’s explosion will travel within the asteroid and cause it to break up into very small pieces.

Unfortunately, for cosmochemist Natalie Starkey, there’s a chance that this plan may not work as expected.

“NASA suggests that a simple kinetic impactor is ‘the most mature approach to deflecting a [near-Earth object], as long as it consists of a small, single body,” Starkey said, according to Express. “However, if we were to intentionally, or accidentally, smash the object during this process, then the outcome for Earth could be harder to predict.”

According to the scientist, the composition of an asteroid plays a huge factor in the success of a kinetic impactor. If an asteroid is made up of very hard materials, there’s a strong chance that it will only break up into large pieces after it gets blown up.

This means that instead of getting hit by one large asteroid, Earth might get pelted by dozens of smaller asteroids. Depending on the sizes of these fragments, some of them might explode mid-air in Earth’s atmosphere while others could cause multiple impact events on the ground.

“Depending on the composition of the space object, it might fragment into tiny dust-sized pieces that could rain down on Earth, or it might break into just a few large pieces, which, if heading for Earth impact, could make matters worse,” Starkey explained.