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NASA has successfully smashed a spacecraft into an asteroid in the first real-world test of a planetary defence mission.

The Double Asteroid Redirection Test (DART) is an attempt to change the orbit of a harmless asteroid, the 160-metre-wide moonlet Dimorphos, around its parent asteroid, Didymos, by flying and crashing a 500-kilogram satellite into Dimorphos head-on. Lessons learned from the impact might one day help us divert dangerous asteroids from hitting Earth.

DART’s final moments were recorded and beamed back to Earth by an onboard camera at a rate of one picture per second. Its final images showed Dimorphos’s rocky surface looming ever closer – until the feed cut out. “As far as we can tell, our first planetary defence test was a success,” DART Mission Systems Engineer .

The resulting explosion of dust and debris was captured by several professional and amateur telescopes on Earth, including the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii. Clearer and more detailed images from a satellite called LICIACube, which accompanied DART to Dimorphos, should appear today, along with images from powerful telescopes like the Hubble and James Webb space telescopes.

Initial calculations suggest that DART finished its 11-million-kilometre journey from Earth just 17 metres off its intended target spot on the asteroid’s surface. It will take weeks or months to find out whether this was enough to change the duration of Dimorphos’s orbit by at least 73 seconds, the minimum number for the mission to be deemed a success. DART’s engineers hope to achieve a change in orbit closer to 10 minutes.

Alongside the information recorded from LICIACube and ground-based and space telescopes, the European Space Agency intends to launch a spacecraft called Hera in 2024 to record the impact’s aftermath in more detail.

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