DART, a kamikaze mission to learn how to protect yourself from asteroids

Of all the horrors that threaten the Earth and especially its inhabitants, the most devastating – but also the one that has the lowest probability of occurring – comes from space: the collision with a large asteroid would make us live the cataclysm that was fatal to dinosaurs (except the ancestors of birds) 66 million years ago.

Two pieces of good news can be opposed to this catastrophic scenario. On the one hand, in the catalog of large so-called near-Earth asteroids, that is to say likely to pass very close to Earth’s orbit, none is likely to strike our planet during the next century. And, on the other hand, humanity is about to test for the first time a parade against this threat, thanks to the American space mission DART (acronym of double asteroid redirection test, knowing that in English, the word dart also designates a “dart”), which is to take off on the night of November 23 to 24 from the base in Vandenberg, California.

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DART is a probe of more than half a ton which, unlike most scientific spacecraft, does not carry any instrument except a camera which will be used for its navigation. What is the point, then, of shipping it to space? DART is actually a suicide bomber. When, in the fall of 2022, he arrives in sight of the asteroid Didymos and its small satellite Dimorphos – which do not constitute a danger to our planet and simply serve as test subjects – he will rush to Dimorphos and s ‘will crash there at the insane speed of 6.6 kilometers per second, or nearly 24,000 km / h.

The goal is then to measure, thanks to observations carried out from the Earth, the slight change of orbit which will have been inflicted on the asteroid-satellite. All in order to verify whether this so-called kinetic impactor deflection technique proves to be an effective planetary defense weapon to modify the trajectory of a future threatening asteroid and make it avoid the Earth. In 2026, the European probe Hera will visit the Didymos-Dimorphos system to measure the extent of the damage.

Asteroid deflection test

CNRS Research Director at the Côte d’Azur Observatory and member of the DART mission, Patrick Michel recalls that this concept, before being taken up by NASA, was born in Europe: “Twenty years ago, the European Space Agency [ESA] created a panel of experts, in which I participated, to deal with the risk of an asteroid impact. We recommended in 2004 a project called Don Quixote that provided for such an asteroid deflection test. Unfortunately, we did not have a budget to continue it. ” In the 2010s, Patrick Michel and his American colleague Andy Cheng, from the Applied Physics Laboratory (Johns Hopkins University, Maryland), gave life to the project and imagined sharing the effort and funding between NASA and ESA.

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