NASA Is Launching Its New DART Spacecraft. To Deflect Asteroids?

Before that happens, it will need to fly 6.8 million miles from Earth to reach its target. The DART mission's goal is to determine the feasibility of a method designed to alter an asteroid's trajectory. If the process works, it could be used to deflect a future asteroid on a collision course with Earth. 

With the launch date fast approaching, NASA provided new details on the mission in a press briefing on Thursday, November 4. "Although there isn't a currently known asteroid that's on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there," said Lindley Johnson, NASA's Planetary Defense Officer.

"The key to planetary defence is finding them well before they are an impact threat," Johnson continued. "We don't want to be in a situation where an asteroid is headed towards Earth and then have to test this capability."

Once the DART spacecraft reaches Dimorphos, a miniature camera-equipped satellite will exit the craft, ten days prior to impact, to orbit the asteroid and collect images and data of the collision. The DART spacecraft, which weighs 548 kg won't cause any significant damage to the asteroid. Instead, it will simply give the space rock a nudge in order to change its trajectory.

What is the probability of a destructive asteroid hitting Earth?

The probability of a civilization-ending asteroid, comparable to the one that wiped out the dinosaurs, hitting Earth any time soon is incredibly small. According to the latest data, the chances of an asteroid large enough to destroy a city hitting Earth are 0.1 percent every year. Even then, if such an asteroid did hit Earth it is unlikely to actually land in a populated area and there is a 70 percent chance it would land in the ocean.

Still, in NASA's press briefing, Johnson said there are over 27,000 near-Earth asteroids out in space, though none are currently thought to pose a real danger to Earth. Several experts have warned, however, that we need to improve our asteroid detection capabilities. In 2019, for example, a large asteroid called '2019 OK' flew between Earth and the Moon and it was only spotted 24 hours before its close flyby.

In another sobering incident, NASA and ESA experts carried out a simulation exercise earlier this year. They came to the conclusion that we are woefully unprepared for the event of a large asteroid making its way to Earth, and we wouldn't be able to prevent an impact with current technologies. All going to plan, NASA's DART mission will mean we will have at least one technology in the world's planetary defense arsenal in the unlikely event that such a scenario became a reality in the near future.