NASA hits an asteroid to save the planet

SPACE – This is a scenario fit for the movies ARMAGEDDON and Don’t Search. What if an asteroid fell straight to Earth? A hypothesis seriously studied by NASA and the European Space Agency (ESA), which allocates its DART and HERA missions, as you can see in the video above.

What is the DART mission?

This mission began on November 24, when the space agency sent a spacecraft aboard a Falcon 9 rocket. This module should crash on the night of September 26 to 27 at 1:14 am French), at a speed of 24,000 km/h on the asteroid Dimorphos, a small “moon” orbiting a larger asteroid, Didymos, located 11 million kilometers from Earth.

“The Dimorphos target is the perfect size for this type of mission, because it’s the size of something that could be a problem for us one day.details of HuffPost Naomi Murdoch, one of the scientists on the DART mission. Why? Because there are many asteroids of this size that we don’t know about yet and that’s where a threat could come from one day. » Rest assured, Dimorphos does not represent a threat to Earth: its orbit around the Sun passes, at its closest, only 7 million kilometers from us.

The moment of impact between the spacecraft sent by NASA and the asteroid promises to be unique, and can be followed live on the video channel of the American agency. This life-size experiment aims to change the period of revolution of a small asteroid around a larger one. “Currently it takes 11:55 for Dimorphos to go around Didymos. It is believed that the effect of DART can reduce the time by 10 minutes”, said Naomi Murdoch. Returning to the terrestrial scenario, the goal is to know if humanity can voluntarily change the trajectory of an asteroid that threatens our planet.

A kamikaze mission in space

To hit such a small target, the ship will drive autonomously for the last four hours, like a self-guided missile. His camera, called Draco, will take the first pictures of the last-minute asteroid, whose shape we still don’t know. At a rate of one frame per second, seen live on Earth with a (small) 45 second delay.

Three minutes after the impact, a shoebox-sized satellite, called LICIACube and released by the craft a few days ago, will pass about 55 km from the asteroid to take pictures. They will be sent back to Earth in the following weeks and months. But to have real data on the effect of DART, we have to wait for the European HERA probe.

This review should begin in October 2024 for the 2026 arrival of Dimorphos. Objective: return to “crime scene” to assess the consequences of the DART effect. “He will give us detailed results about the size of the crater. But it will also give us, for the first time, detailed information about the internal structure of an asteroid. It never did. And this is thanks to a radar whose expertise is French”explained Patrick Michel, research director of CNRS and scientific manager of the Hera mission of ESA.

Scientists expect to be surprised by the results of the investigations. with “We ignore almost everything” of these celestial objects, shows the astrophysicist. “This is a new world for us to discover”. For him, the asteroids not just boring pebbles in space, but fascinating and complex small geological worlds, with craters, basins, rock fields, particle ejections… »

But science struggles to understand these territories because on it, gravity is very weak compared to that on Earth: the nature of matter there. “Totally counter-intuitive, we can’t rely on images to know how asteroids behave, we also have to ‘touch’ them”insisted Patrick Michel.

Back to the origin of the solar system

Binary systems, such as Didymos and its satellite Dimorphos, represent about 15% of known asteroids and so far have not been explored. Shape, mass, chemical composition, internal structure, impact resistance, crater shape caused by DART: The HERA instruments should reveal the secrets of Dimorphos. At the end of the mission, a micro-satellite will land on top of it to measure how it bounces.

“Today we are in a time where all solid surfaces in the Solar System have craters. To return to the original scenario, we need to understand what happens when two bodies collide.. Not in the laboratory, but on a real scale thanks to the DART-HERA couple, scientists hope.

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