NASA’s DART mission successfully smashed into asteroid Dimorphos

The Double Asteroid Redirection Test spacecraft beamed back its final moments before colliding with the asteroid Dimorphos in an attempt to change its orbit, and the collision was captured by telescopes on Earth

By Alex Wilkins

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

The Double Asteroid Redirection Test (DART) is an attempt to change the orbit of a harmless asteroid, the 160-metre-wide asteroid Dimorphos, around its parent asteroid, Didymos, by flying and crashing a 500-kilogram satellite into the smaller asteroid head-on. Lessons learnt 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’ 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 Elena Adams told a press conference.

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

Initial calculations suggest that DART finished its 11 million kilometre journey from Earth just 17 metres off its intended target spot. It will take weeks or months to find out whether this was still enough to change the duration of Dimorphos’ 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 around 10 minutes.

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

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