NASA’s DART spacecraft hits a target asteroid in the first planetary defense test

NASA's DART spacecraft hits a target asteroid in the first planetary defense test
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Sept 26 (Reuters) – NASA’s DART spacecraft crashed into a distant asteroid at hypersonic speeds in the world’s first test of its planetary defense system on Monday, designed to prevent a doomsday meteorite from hitting Earth.

Humanity’s first attempt to alter the motion of an asteroid, or any celestial body, took place in a NASA webcast from the mission operations center outside Washington, DC, 10 months after DART’s launch.

The live broadcast showed images captured by DART’s camera as a cube-shaped “impact vehicle” no bigger than a vending machine with two rectangular solar arrays entered the roughly football-stadium-sized asteroid Dimorphos at 7:14 p.m. EDT. (2314 GMT) about 6.8 million miles (11 million km) from Earth.

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The $330 million mission, nearly seven years in development, was designed to determine whether a spacecraft could change the trajectory of an asteroid by sheer kinetic force and move it enough to keep Earth out of harm’s way.

Whether the experiment was successful beyond its intended effect will not be known until ground-based telescope observations of the asteroid next month. But NASA officials on Monday hailed the immediate results of the test, saying the spacecraft had achieved its goal.

“NASA works for the good of humanity, so for us to do something like this is the ultimate fulfillment of our mission — a demonstration of technology that, who knows, could one day save our home,” NASA Deputy Administrator Pam Melroy, a retired astronaut, said moments after the impact. .

Launched on a SpaceX rocket in November 2021, DART spent most of its journey under the guidance of NASA flight directors, with control handed over to an autonomous on-board navigation system during the final hours of the journey.

The impact of the bullseye was monitored in real time Monday evening from the mission operations center at Johns Hopkins University’s Applied Physics Laboratory in Laurel, Maryland.

Cheers erupted from the control room as second-by-second images of the target asteroid captured by DART’s onboard camera zoomed in and filled the television screen of NASA’s live webcast before the signal eventually faded. .

DART’s celestial target was an elongated asteroid “moon” about 560 feet (170 meters) in diameter and orbiting a parent asteroid called Didymos, the Greek word for twin, as part of a binary pair of the same name.

Neither object poses any threat to Earth, and NASA scientists said their DART test could not inadvertently create a new threat.

Dimorphos and Didymos are small compared to the cataclysmic asteroid Chicxulub, which struck Earth about 66 million years ago and wiped out about three-quarters of the world’s plant and animal species, including the dinosaurs.

According to NASA scientists and planetary defense experts, smaller asteroids are more common and of greater theoretical concern in the near future, making the Didymos pair suitable test subjects for their size. While an asteroid the size of Dimorphos may not pose a threat on a planetary scale, it can level a large city with a direct hit.

Also, the relative proximity of the two asteroids to Earth and their binary configuration make them ideal for the first proof-of-concept mission of DART, short for Double Asteroid Redirection Test.


The mission was a rare example of a NASA spacecraft having to crash to succeed. DART flew directly at Dimorphos at 15,000 miles per hour (24,000 km/h), generating thrust that scientists hoped would be enough to bring its orbital path closer to the parent asteroid.

APL engineers said the spacecraft likely broke up, leaving a small impact crater on the asteroid’s rocky surface.

The DART team said it expected to shorten Dimorphos’ orbital path by 10 minutes, but would consider at least 73 seconds a success, and that the exercise would prove to be a viable technique for redirecting an asteroid on a collision course with Earth — if one is discovered.

Hitting an asteroid millions of miles away years in advance might be enough to safely alter it.

Previous calculations of Dimorphos’ starting location and orbital period were made during a six-day observing period in July and will be compared with post-impact measurements in October to determine if and how much the asteroid has twisted.

Monday’s test was also observed by a camera mounted on a briefcase-sized mini-spacecraft launched before the DART days, as well as by ground-based observatories and the Hubble and Webb space telescopes, but images from them were not immediately available.

DART is the latest of several NASA missions in recent years to explore and interact with asteroids, the primordial rocky remnants of the Solar System’s formation more than 4.5 billion years ago.

Last year, NASA launched a probe to travel to the Trojan asteroid group orbiting near Jupiter, while the capture spacecraft OSIRIS-REx returns to Earth in October 2020 with a sample collected from asteroid Bennu.

Dimorphos sunflower is one of the smallest astronomical objects to receive a permanent name and is one of the 27,500 known near-Earth asteroids of all sizes tracked by NASA. Although none are known to pose a foreseeable threat to humanity, NASA estimates that many more near-Earth asteroids remain undiscovered.

(This story corrects the name in paragraph 6 from Palm to Pam)

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Reporting by Steve Gorman in Los Angeles; Additional reporting by Joey Roulette in Los Angeles; Edited by Sandra Maler and Stephen Coates

Our standards: Thomson Reuters Trust Principles.

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