If science fiction movies have taught us anything, it’s that saving Earth from a killer asteroid is going to take some big drills and probably nuclear weapons. Thankfully, if a particularly large space rock ever were to threaten Earth, our plan of attack would probably be a bit more level-headed. That is, as long as we saw the threat far enough in advance.

A team of researchers from MIT has thought long and hard about how to save Earth from a killer asteroid, and they’ve come up with a plan that wouldn’t require any particularly drastic measures. The key to the plan is being able to spot the object well ahead of time.

The idea is that by studying the path of an asteroid that will eventually impact Earth, scientists could pinpoint a location before which the object could be easily diverted. This location is known as a “keyhole passage,” or a window in space through which the asteroid would pass that would indicate it was on a collision course with our planet.

“People have mostly considered strategies of last-minute deflection, when the asteroid has already passed through a keyhole and is heading toward a collision with Earth,” lead researcher MIT’s Sung Wook Paek, who led the study, said in a statement. “I’m interested in preventing keyhole passage well before Earth impact. It’s like a preemptive strike, with less mess.”

This method for diverting an asteroid from an impact with Earth would require much observation, and scientists would need to know a lot about the space rock in order to determine whether such a mission would save Earth. That means knowing how large the asteroid is and its mass.

If an object could be identified before it passes through the keyhole, the chances of diversion are much greater than if astronomers spotted the rock later on. Missions to launch small impactors to push the rock on a different course would work well for objects spotted very early, but that means being able to spot those rocks as soon as possible.

Mike Wehner has reported on technology and video games for the past decade, covering breaking news and trends in VR, wearables, smartphones, and future tech. Most recently, Mike served as Tech Editor at The Daily Dot, and has been featured in USA Today, Time.com, and countless other web and print outlets. His love of reporting is second only to his gaming addiction.