Space

Nasa succeeds in pushing asteroid into new orbit

Humanity alters motion of celestial body for the first time after agency smashed spacecraft into moonlet in September

The asteroid Dimorphos, showing a plume after it was hit by the Double Asteroid Redirect Test (Dart) in September, is pictured with its parent asteroid Didymos (top). Image: ASI/Nasa

Wed Oct 12 2022 - 08:42

The spacecraft Nasa deliberately crashed into an asteroid last month succeeded in nudging the rocky moonlet from its natural path into a faster orbit, marking the first time humanity has altered the motion of a celestial body, the US space agency announced on Tuesday.

The $330 million (€339 million) proof-of-concept mission, which was seven years in development, also represented the world’s first test of a planetary defence system designed to prevent a potential doomsday meteorite collision with Earth.

Findings of telescope observations unveiled at a Nasa news briefing in Washington confirmed the suicide test flight of the Dart spacecraft on September 26th achieved its primary objective: changing the direction of an asteroid through sheer kinetic force.

Astronomical measurements over the past two weeks showed the target asteroid was bumped slightly closer to the larger parent asteroid it orbits and that its orbital period was shortened by 32 minutes, Nasa scientists said.

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“This is a watershed moment for planetary defence and a watershed moment for humanity,” Nasa chief Bill Nelson told reporters in announcing the results. “It felt like a movie plot, but this was not Hollywood.”

Last month’s impact, 10.9 million km (6.8 million miles) from Earth, was monitored in real time from the mission operations centre at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, where the spacecraft was designed and built for Nasa.

Dart’s celestial target was an egg-shaped asteroid named Dimorphos, roughly the size of a football stadium, that was orbiting a parent asteroid about five times bigger called Didymos once every 11 hours, 55 minutes.

The test flight concluded with the Dart impactor vehicle, no bigger than a refrigerator, slamming directly into Dimorphos at about 14,000 miles per hour (22,531kph).

Comparison of pre- and post-impact measurements of the Dimorphos-Didymos pair as one eclipses the other shows the orbital period was shortened to 11 hours, 23 minutes, with the smaller object bumped tens of meters closer to its parent.

Tom Statler, Dart programme scientist for Nasa, said the collision also left Dimorphos “wobbling a bit,” but additional observations would be necessary to confirm that.

The outcome “demonstrated we are capable of deflecting a potentially hazardous asteroid of this size,” if it were discovered well enough in advance, said Lori Glaze, director of Nasa’s planetary science division. “The key is early detection.”

Neither of the two asteroids involved, nor Dart itself, short for Double Asteroid Redirection Test, posed any actual threat to Earth, Nasa scientists said. — Reuters

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