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

Sept 26 (Reuters) – NASA’s DART spacecraft successfully slammed into a distant asteroid at hypersonic speed on Monday in the world’s first test of a planetary defense system, designed to prevent a possible meteorite collision with Earth. Land.

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

The live feed showed images taken by DART’s camera as the cube-shaped “impactor” vehicle, no bigger than a vending machine with two rectangular solar panels, slammed into the asteroid Dimorphos, roughly the size of a stadium of football, at 7:14 p.m. EDT. (2314 GMT) about 6.8 million miles (11 million kilometers) from Earth.

The $330 million mission, some seven years in the making, was designed to determine if a spacecraft is capable of changing the trajectory of an asteroid through sheer kinetic force, throwing it off course enough to keep Earth out of danger.

Whether the experiment was successful beyond achieving the predicted impact will not be known until more observations of the asteroid with ground-based telescopes are made next month. But NASA officials praised the immediate result of Monday’s test, saying the spacecraft achieved its purpose.

“NASA works for the benefit of humanity, so for us it is the ultimate fulfillment of our mission to do something like this: a demonstration of technology that, who knows, could one day save our home,” said NASA deputy administrator. NASA, Palm Melroy, a retired astronaut. ., she said minutes after impact.

DART, launched by a SpaceX rocket in November 2021, made most of its journey under the direction of NASA flight directors, with control handed over to an onboard autonomous navigation system in the final hours of the journey.

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

Applause erupted from the control room as second-by-second images of the target asteroid, captured by DART’s onboard camera, grew larger and finally filled the television screen of NASA’s live feed just before it signal was lost, confirming that the spacecraft had crashed into Dimorphos. . .

DART’s celestial target was an oblong “moonlet” asteroid about 560 feet (170 meters) in diameter that orbits a parent asteroid five times larger called Didymos as part of a binary pair with the same name, the Greek word for twin.

Neither object poses a real threat to Earth, and NASA scientists said their DART test couldn’t create a new hazard by mistake.

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

Smaller asteroids are much more common and present a greater theoretical concern in the short term, making the Didymos pair suitable test subjects for their size, according to NASA scientists and planetary defense experts. A Dimorphos-sized asteroid, while not capable of posing a planet-wide threat, could level a major city with a direct hit.

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

ROBOTIC SUICIDE MISSION

The mission represented a rare case where a NASA spacecraft had to crash in order to be successful. DART flew directly into Dimorphos at 15,000 miles per hour (24,000 kph), creating the force that scientists hope will be enough to bring its orbital path closer to the parent asteroid.

APL engineers said the spacecraft likely shattered and left a small impact crater in the rock-strewn surface of the asteroid.

The DART team said it hopes to shorten Dimorphos’s orbital path by 10 minutes, but would consider at least 73 seconds a success, showing the exercise is a viable technique for deflecting an asteroid on a collision course with Earth, if ever. one is discovered.

A nudge to an asteroid millions of miles away years in advance might be enough to deflect it safely.

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

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

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

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

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

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

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