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

NASA's DART spacecraft hits target asteroid in first planetary defense test
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September 26 (Reuters) – NASA’s DART spacecraft successfully crashed into a distant asteroid at hypersonic speed on Monday in a test of the world’s first planetary defense system designed to avoid a possible doomsday meteorite collision with Earth.

It’s humanity’s first attempt at altering the motion of an asteroid or any celestial body, 10 months after DART’s launch, played out in a NASA webcast from the mission operations center outside Washington DC.

The live stream showed footage captured by DART’s camera at 7:14 p.m. as the “striking” cube-shaped vehicle, no larger than a vending machine with two rectangular solar panels, crashed into the asteroid Dimorphos, about the size of a football stadium. (2314 GMT) is about 6.8 million miles (11 million km) from Earth.

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The $330 million mission, which spanned nearly seven years, was designed to determine whether a spacecraft could alter an asteroid’s trajectory with pure kinetic force and deflect Earth enough to keep it out of harm’s way.

Whether the experiment succeeds beyond achieving its intended effect will not be known until next month’s ground-based telescope observations of the asteroid. But NASA officials hailed the immediate result of Monday’s test, saying the spacecraft had achieved its purpose.

“NASA works for the benefit of humanity, so for us the ultimate fulfillment of our mission to do something like this – a tech demonstration that, who knows, could one day save our home,” said Pam Melroy, a retired astronaut, NASA Deputy Administrator. she said minutes after the crash.

Launched by a SpaceX rocket in November 2021, DART made most of its journey under the guidance of NASA’s flight directors, handing control over to an autonomous in-vehicle navigation system in the final hours of the journey.

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

Applause broke out from the control room as seconds-by-second images of the target asteroid captured by DART’s onboard camera grew larger and filled the TV screen of NASA’s live webcast just before the signal disappeared, confirming that the spacecraft had crashed into Dimorfos. .

DART’s celestial target was a rectangular asteroid “moonlet” about 560 feet (170 meters) in diameter orbiting a five times larger main asteroid named Didymos as part of a binary pair of the same name, Greek for twin.

Neither object poses a real threat to Earth, and NASA scientists said the DART tests could not accidentally pose a new danger.

Dimorphos and Didymos are tiny compared to the terrifying asteroid Chicxulub, which slammed into Earth about 66 million years ago, wiping out about three-quarters of the world’s plant and animal species, including dinosaurs.

According to NASA scientists and planetary defense experts, smaller asteroids are much more common and present a larger theoretical concern in the near term, making the Didymos pair as test subjects fit for their size. While not capable of posing a planet-wide threat, a Dimorfos-sized asteroid could devastate a major city with a direct hit.

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


The mission represented a rare instance where a NASA spacecraft had to crash in order to be successful. DART flew directly into Dimorfos at 15,000 miles per hour (24,000 kph), creating what scientists hope would be enough to bring the orbital track closer to the parent asteroid.

APL engineers said the spacecraft likely broke apart, leaving a small impact crater on the asteroid’s rock-filled 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 the exercise would prove a viable technique for deflecting an asteroid on a collision course with Earth – if one were discovered.

One nudge to an asteroid millions of miles away might be enough to safely reorient it.

Earlier calculations of Dimorphos’ initial position and orbital period were made during a six-day observation period in July and will be compared with post-impact measurements made in October to determine whether and how much the asteroid moved.

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

DART is the latest of several NASA missions in recent years to explore and interact with asteroids, primordial rocky remains from the formation of the solar system more than 4.5 billion years ago.

Last year, NASA launched a probe for a trip to the Trojan asteroid clusters orbiting near Jupiter, while the grab-and-go spacecraft OSIRIS-REx returns to Earth in October 2020 with a sample collected from the asteroid Bennu.

The Dimorphos moon bear is one of the smallest astronomical objects to receive a permanent name, and is one of 27,500 known asteroids near Earth of all sizes tracked by NASA. While none are known to pose a foreseeable danger to humanity, NASA estimates that many more asteroids remain undetected in the near-Earth environment.

(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; Editing Sandra Maler and Stephen Coates

Our standards: Thomson Reuters Trust Principles.

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