NASA strikes asteroid with spacecraft in historic planetary defense mission

NASA on Monday successfully struck a tiny asteroid more than 7 million miles from Earth with a 1,000-pound spacecraft, completing the world’s first planetary defense mission.

The Double Asteroid Redirection Test (DART) spacecraft slammed into the asteroid Dimorphos at roughly 7:14 p.m. ET at a speed of more than 14,000 miles per hour.

It’s the first time humanity has ever purposefully struck an object in space. NASA and Johns Hopkins Applied Physics Laboratory officials who have been working on the DART mission for years erupted into applause as soon as the spacecraft collided with Dimorphos.

DART first launched into space last November, so the mission’s success completes a 10-month flight toward Dimorphos, an asteroid that weighs around 5 billion kilograms.

Dimorphos is part of the binary asteroid system Didymos, which means twin in Greek. In its system, Dimorphos orbits the larger asteroid Didymos.

While neither Dimorphos nor Didymos posed a threat to Earth, the DART mission serves as a key test of deflecting a future asteroid or space object that could threaten the planet.

NASA Administrator Bill Nelson on Monday praised the DART mission and thanked the team for its years of work.

“I believe it’s going to teach us how one day to protect our own planet,” Nelson said of DART in a video statement. “We are showing that planetary defense is a global endeavor, and it is very possible to save our planet.”

The mission is considered to be a huge success, and the DART team did not encounter any difficulties or setbacks. Elena Adams, DART’s systems engineer, said they created contingency plans for possible hurdles but did not end up employing any. 

Adams led a round of applause for the mission.

“Earthlings should sleep better,” Adams said at a Monday press conference. “Definitely I will.”

The DART spacecraft likely obliterated upon impact and its debris likely scattered across space or lodged into the asteroid, the team said. It’s possible the spacecraft created a 10-meter or 20-meter crater in Dimorphos.

The DART team estimated they would have a full assessment on the collision in about two months, including details of how much the spacecraft pushed the asteroid out of its orbit. NASA and APL were hoping to change the orbit of Dimorphos by several minutes.

Observatory teams using ground-based telescopes may discuss individual results in the coming days. The European Space Agency has a follow up mission called Hera, which will launch a spacecraft toward Didymos in 2024. The spacecraft should arrive in 2026 and provide greater detail about the collision.

The DART team will be moving on to other missions. While the team feels accomplished, Julie Bellerose, DART’s navigation lead at NASA, said she felt a little bittersweet when viewing the final image of DART smashing into Dimorphos.

“There’s a lot of emotion,” she said. “There was a lot of friendship being built. I’m relieved to see that it went so well … but at the end, I shed a tear.”

Updated 9:30 p.m.