Each year, tens of thousands of meteorites run a collision course with Earth. The good news is that most of these meteorites are small and burn up in the atmosphere before reaching land (or water). However, scientists believe asteroids with 1 km (0.62 mi) diameter strike Earth about once every 500,000 years on average, causing significant damage to ecosystems and life. Rather than waiting for another of these asteroids to stroke, NASA has proposed a new deflection project that it plans to test in the near future.
Dubbed the Double Asteroid Redirection Test (DART), this bold initiative is the brainchild of researchers at the Johns Hopkins Applied Physics Laboratory, which received the green light of approval from NASA on June 23.
So, how does DART work exactly? It may sound like something out of a science-fiction movie, but researchers plan to use kinetic energy to shift the asteroid out of Earth’s orbit. In the past, scientists have proposed launching explosive-tipped missiles at asteroids on a collision course with Earth. The problem with this idea, however, is that it may turn a single asteroid into dozens or even hundreds of smaller yet still catastrophically damaging asteroids. To prevent this from happening, researchers have proposed an alternative solution: DART.
Of course, DART wouldn’t cause any significant change in an major asteroid’s trajectory — and that’s okay. Researchers say that even a small change in trajectory would be enough to shift it away from Earth and avoid a collision, assuming it’s performed at the right time.
Unfortunately, though, it will be a while before we know whether or not DART actually works. NASA is planning to test the project, but this won’t occur until 2024 when a nonthreatening asteroid is expected to fly by. At this time, NASA will fly DART directly into the asteroid at speeds of approximately 3.7 miles per second with the goal of changing its trajectory. If successful, DART could one day be used to divert other, more threatening asteroids.
“DART is a critical step in demonstrating we can protect our planet from a future asteroid impact,” said Andy Cheng, one of the project’s team leaders. “Since we don’t know that much about their internal structure or composition, we need to perform this experiment on a real asteroid. With DART, we can show how to protect Earth from an asteroid strike with a kinetic impactor by knocking the hazardous object into a different flight path that would not threaten the planet.”