NASA’s spacecraft will crash into an asteroid to test a deflection technique

“The right time to deflect an asteroid is as far as we can from Earth,” NASA’s planetary defense officer Lindley Johnson said at a news conference. “The farther you are in space, years before the impact, the less force is needed to change the orbit enough because it will be a mistake instead of a blow.”

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The DART spacecraft, built and operated by the Applied Physics Laboratory at Johns Hopkins University under the direction of NASA’s Office of Planetary Defense Coordination, will be launched with a SpaceX Falcon 9 rocket from the base of the space force. Vandenberg in California at 12:20, Houston time.

It will travel 10 months to reach one 525-foot asteroid moon called Dimorphos orbiting a 2,500-foot asteroid called Didymos. The DART spacecraft is scheduled to collide with the moon in orbit in the fall of 2022. It will travel at 15,000 mph.

The cost of the mission is $ 330 million, which covers everything from concept development to collision and collision. data analysis continuing until 2023.

“We don’t want to be in a situation where an asteroid goes to Earth and then has to test that kind of ability,” Johnson said. “We want to know how the spacecraft works and what the asteroid’s reaction to impact will be before it reaches a situation like this.”

NASA chose these asteroids because they are relatively close to Earth (approximately 6.8 million miles when the DART spacecraft visits), and scientists with terrestrial telescopes can observe and measure impact.

Asteroids seem little more than a single point of light, but scientists have observed them for decades and know that Dimorphos orbits Didymos every 11 hours and 55 minutes. If the DART impact works, it will accelerate the orbit of Dimorphos for a few minutes (that is, it will take, for example, 11 hours and 45 minutes).

The mission carries a case-sized satellite created by the Italian Space Agency that will be ejected from the DART spacecraft 10 days before impact. This satellite will pass Dimorphos three minutes after DART sinks it, taking pictures of the impact and its consequences.

Andy Cheng, leader of the DART research team with the Johns Hopkins Applied Physics Laboratory, said it will be important to measure impulse transfer. The briefcase-sized satellite will help with this.

“How much momentum do we give the asteroid by hitting it with the DART spacecraft?” Cheng asked during the press conference. “And if one day an asteroid is discovered in a course of collision with Earth, and we have an idea of ​​the size of the asteroid and how quickly it will arrive and when it will arrive, this kind of information, we will have a idea of ​​how much momentum we need for this asteroid to lose the Earth. ”

In 2026, the European Space Agency’s Hera mission is expected to meet with the same two asteroids to conduct a detailed survey.

Asteroids are rocky relics that date back to the formation of our solar system. They vary in shape, size and composition. Some are solid, dense objects, while others are piles of rubble joined by their own weak gravity.

Scientists have identified and are tracking more than 26,000 asteroids close to Earth. Nearly 10,000 of these are 500 feet or more, and the approximately 2,200 of these massive asteroids whose orbits are located 4.6 million miles from Earth are classified as potentially dangerous.

Scientists estimate that there are approximately 15,000 asteroids close to Earth 500 feet or more in size that have not yet been discovered.

In 2013, an undetected asteroid exploded over Chelyabinsk, Russia. The blast and shock wave affected six cities in the region, injuring more than 1,600 people and causing damage of approximately $ 30 million.

The Chelyabinsk asteroid was about 60 feet in size. NASA estimates that asteroids around this size hit Earth once or twice a century.

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The agency expects even larger objects to collide with the Earth in centuries or millennia. No known asteroid poses a threat to our planet at least for the next century. An asteroid about 500 feet long, like the asteroid Dimorphos that DART is aiming at, could cause regional devastation.

That’s why the DART mission is just a starting point. After this mission, NASA hopes to try other methods to deflect an asteroid. With the gravity tractor technique, for example, a spacecraft would encounter an asteroid and fly next to it. The mutual gravitational pull between the satellite and the asteroid would slowly alter the asteroid’s course.

“Fortunately, asteroid impacts don’t happen that often, and so we think we’ll have time to do that kind of thing,” Johnson said. “And we never know what the technology might be like in the future when we’re really faced with an asteroid impact. That’s just the beginning.”