Nasa managed to deflect an asteroid from its path in an Earth defense test

The Dart mission craft had deliberately rammed into its target, the asteroid Dimorphos, which is the satellite of a larger asteroid named Didymos.

The NASA device managed to move it by reducing its orbit by 32 minutes, said the head of the space agency, Bill Nelson, during a press conference.

This is "a watershed moment for planetary defense, and a watershed moment for humanity," he said.

It would already have been "considered a huge success if it (the craft) had only reduced the orbit by about 10 minutes. But it actually reduced it by 32 minutes," he added.

With this mission, "Nasa has proven that we are serious as defenders of the planet," he said.

Dimorphos, located some 11 million kilometers from Earth at the time of impact, is about 160 meters in diameter and poses no danger to our planet.

It has so far circumnavigated Didymos in 11 hours and 55 minutes, a period shortened to 11 hours and 23 minutes, Nelson said.

"It looks like a movie script. But it's not Hollywood (...). This mission shows that NASA is trying to be ready for anything the universe could throw at us," he said. he declares.

Photo provided by NASA on October 11, 2022 showing the asteroid Dimorphos Handout NASA/Jons Hopkins APL/AFP

If the objective remained relatively modest compared to the disaster scenarios of science fiction films like "Armageddon", this unprecedented mission of "planetary defense", named Dart (dart, in English), is the first to test such a technique.

It allows NASA to train in case an asteroid threatens to hit Earth one day.

egg shape

To confirm that the trajectory of the asteroid had indeed been altered, it was necessary to wait for scientists to analyze data from telescopes on the ground.

The latter observed the variation in brightness when the small asteroid passes in front of and behind the large one.

Soon after the collision, early images -- taken by ground-based telescopes and the onboard nano-satellite for the LICIACube mission -- showed a vast dust cloud around Dimorphos, stretching for thousands of kilometres.

Then the James Webb and Hubble telescopes, the most powerful space observatories, revealed detailed views of the impact of NASA's spacecraft, showing in particular the movement of ejecta - the material torn from the star.

All this should make it possible to better understand the composition of Dimorphos, representative of a population of fairly common asteroids, and therefore to measure the exact effect that this technique - called kinetic impact - can have on them.

Image provided by NASA on October 11, 2022 showing the last complete image of the asteroid Dimorphos Handout NASA/Jons Hopkins APL/AFP

Images of Dimorphos, taken shortly before impact, show its surface to be gray and rocky and egg-shaped.

Knowing these details is important in case humanity ever finds itself forced to crash into an object approaching Earth.

The ship had traveled for ten months since its takeoff in California.

Nearly 30,000 asteroids of all sizes have been cataloged in the vicinity of the Earth (they are called near-Earth objects, that is to say that their orbit crosses that of our planet).

Today, none of these known asteroids threaten our planet for the next 100 years.

Except that they are not yet all identified.

Those of a kilometer or more have almost all been spotted, according to the scientists.

But they estimate that they only know about 40% of asteroids measuring 140 meters or more -- those capable of devastating an entire region.

© 2022 AFP