NASA’s DART spacecraft crashes into an asteroid in the world's first planetary defense test

This test mission could save Earth from future threats involving asteroid collision.
Deena Theresa
Didymos' final images from DART
Didymos' final images from DART


We now have what the dinosaurs didn't.

In the world's first planetary defense technology demonstration, NASA's Double Asteroid Redirection Test (DART) made history as it successfully slammed into an asteroid target on Monday. The first 'attempt' to move an asteroid in space, the probe tested a way to protect our planet from future hazards and potential impacts.

Mission control at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, announced the successful impact of the 1,260-pound (570-kilogram) box-shaped spacecraft a few hours ago, at 7:14 pm EDT(2314 GMT) while flying at 14,000 mph (22,500 kph), through the final 56,000 miles (90,000 kilometers) of space into the asteroid.

Last November, NASA launched DART successfully on SpaceX's Falcon 9 rocket from the Vandenberg Space Force Base in California.

NASA’s DART spacecraft crashes into an asteroid in the world's first planetary defense test
DART test mission


For the first time, a loss of signal meant a successful mission

Although the team will require weeks to gauge the success of DART's test, hitting the small asteroid that resulted in a loss of signal was a massive achievement.

"As far as we can tell, our first planetary defense test was a success," said Elena Adams, DART's mission systems engineer at the Johns Hopkins University Applied Physics Laboratory (JHUAPL), said during a news conference held about an hour after the impact. "I think Earthlings should sleep better. Definitely, I will."

The spacecraft crashed into an asteroid moonlet seven million miles (11 million kilometers) from Earth. Called Dimorphos, the small body is just 530 feet (160 meters) in diameter and orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. The goal was to change the orbit of Dimorphos around its larger asteroid parent, Didymos, demonstrating a feasible mitigation technique for protecting humanity from an Earth-bound asteroid or comet if one were discovered.

Both Dimorphos and Didymos do not pose a threat to Earth.

NASA’s DART spacecraft crashes into an asteroid in the world's first planetary defense test
Asteroid moonlet Dimorphos as seen by the DART spacecraft 11 seconds before impact. DART’s on board DRACO imager captured this image from a distance of 42 miles (68 kilometers).

A smooth, exciting journey sans glitches

The mission's success confirmed that NASA could navigate a probe to collide with an asteroid to deflect it, a technique known as kinetic impact.

"At its core, DART represents an unprecedented success for planetary defense, but it is also a mission of unity with a real benefit for all humanity," NASA Administrator Bill Nelson said in a statement. "As NASA studies the cosmos and our home planet, we’re also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth."

Anticipation was in the air at DART's mission control center at JHUAPL as the spacecraft swiftly moved towards its target.

"This asteroid was coming into the field of view for the first time," Adams said. "We really had no idea what to expect. We didn't really know the shape of the asteroid, but we knew we were going to hit. So I think all of us were kind of holding our breath. I'm kind of surprised none of us passed out, actually."

NASA’s DART spacecraft crashes into an asteroid in the world's first planetary defense test
The last complete image of asteroid moonlet Dimorphos, taken by the DRACO imager on NASA’s DART mission from ~7 miles (12 kilometers) from the asteroid and 2 seconds before impact.

Backup plans didn't have to be used

Engineers had 21 different contingency plans in place but didn't have to employ any.

"This mission was straight down the middle of what our expectations were, and there were no adjustments needed," Mark Jensenius, DART Smart Nav guidance engineer at the Johns Hopkins University Applied Physics Laboratory (JHUAPL), which operates the DART mission for NASA, said during the news conference.

As DART approached Dimorphus, it used its sole instrument, the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), to autonomously navigate its impact zone. As the probe closed in on the asteroid, boulders and shadowed terrain came into focus. Then, like clockwork, the live feed from DART went black, and flight controllers inside DART's mission operations center erupted in joy.

NASA’s DART spacecraft crashes into an asteroid in the world's first planetary defense test
DART’s final look at the asteroid moonlet Dimorphos before impact. DART’s impact occurred during transmission of the image to Earth, resulting in a partial picture.

How faster will Dimorphos move?

This isn't the end of the mission. In fact, it's just beginning.

"We'll spend the next months and years doing analysis, of course. Our job has just started, but it really looks just amazing," Carolyn Ernst, instrument scientist for DART's DRACO camera and a planetary scientist at JHUAPL, said during the news conference.

NASA’s DART had tested a small satellite called the LICIACube (pronounced LEE-cha-cube, and short for Light Italian CubeSat for Imaging Asteroids) for use on this mission, making sure it worked properly before the impact. It sent Earth a host of images captured just three minutes after the impact.

The global team employs dozens of telescopes stationed worldwide and in space to observe the asteroid system. In space, NASA's James Webb Space Telescope, the Hubble Space Telescope, and the Lucy spacecraft on its asteroid mission bore witness to the crash, tracking from their respective points. On Earth, ground-based telescopes will follow the binary asteroid system to see how much faster Dimorphos moves in its orbit.

The orbit used to take 11 hours and 55 minutes. "Our requirements are for 73 seconds, but we actually think we're going to change by about 10 minutes," said Tom Statler, NASA's DART program scientist. The process is likely to take around two months.

More details awaited

According to the press release, the scientists will characterize the ejecta produced over the coming weeks and precisely measure Dimorphos’ orbital change to determine how effectively DART deflected the asteroid. "The results will help validate and improve scientific computer models critical to predicting the effectiveness of this technique as a reliable method for asteroid deflection," it said.

Four years from now, the European Space Agency's Hera project will follow up on DART's impact. It will launch a spacecraft to the asteroid in 2024, orbiting Dimorphos-Didymos, to focus on the crater left by DART's collision and the measurement of the very little-known asteroid Dimorphos' mass.

“Coupled with enhanced capabilities to accelerate finding the remaining hazardous asteroid population by our next Planetary Defense mission, the Near-Earth Object (NEO) Surveyor, a DART successor could provide what we need to save the day," said Lindley Johnson, NASA’s Planetary Defense Officer.

The planetary defense test is an enormous milestone for NASA - embarking on a new era of humankind.

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