NASA prepares to deflect the asteroid, in the key test of planetary defense

A man sits at his post inside the Mission Operations Center for the Double Asteroid Redirection Test (DART) spacecraft, which is rapidly approaching its target.

I bet the dinosaurs wish they had thought of this.

On Monday, NASA will attempt a feat that humanity has never accomplished before: deliberately hitting a spacecraft into an asteroid to slightly deflect its orbit, in a key test of our ability to prevent cosmic objects from ravaging life on Earth. .

The Double Asteroid Redirection Test (DART) spacecraft launched from California last November and is fast approaching its target, which will strike at around 14,000 miles per hour (23,000 km / h).

To be sure, neither the lunar asteroid Dimorphos, nor the older brother it orbits, called Didymos, pose a threat as the pair revolve around the Sun, passing approximately seven million miles from Earth at the closest approach.

But the experiment is what NASA thought it important to conduct before a real need is discovered.

“This is an exciting time, not just for the agency, but in the history of space and the history of humanity quite frankly,” Lindley Johnson, a NASA planetary defense officer, told reporters in a briefing Thursday.

If all goes according to plan, the impact between the car-sized spacecraft and the 530-foot (160-meter, or two Statues of Liberty) asteroid is expected to take place at 19:14 Eastern time (2314 GMT). and can be followed on a NASA Live Stream.

By hitting Dimorphos head-on, NASA hopes to push it into a smaller orbit, reducing the time it takes to surround Didymos by ten minutes, which is currently 11 hours and 55 minutes, a change that will be detected by ground-based telescopes on days in to follow.

The proof-of-concept experiment will turn into reality what was previously only attempted in science fiction, particularly films like “Armageddon” and “Don’t Look Up”.

Graphic on NASA's DART mission to crash a small spaceship into a mini-asteroid to change its trajectory as a test for any paws

Chart on NASA’s DART mission to crash a small spaceship into a mini-asteroid to change its trajectory as a test for any potentially dangerous asteroids in the future.

Technically challenging

As the spaceship moves through space, flying autonomously for the final stage of the mission as a self-guided missile, its main camera system, called DRACO, will begin broadcasting the first images of Dimorphos.

“It will start out as a small light spot and then eventually enlarge and fill the entire field of view,” said Nancy Chabot of the Johns Hopkins Applied Physics Laboratory (APL), who hosts mission control in a recent briefing.

“These images will continue until they do,” the planetary scientist added.

A few minutes later, a toaster-sized satellite called LICIACube, which separated from DART a couple of weeks earlier, will make a close pass of the site to capture images of the collision and ejecta, the pulverized rock ejected from the impact. .

The LICIACube photo will be sent back in the following weeks and months.

Looking at the event as well: a series of telescopes, both on Earth and in space, including the recently operational James Webb, that may be able to see a cloud of dust lighting up.

Finally, a complete picture of the system’s appearance will be revealed when a European Space Agency mission four years later, called Hera, arrives to examine Dimorphos’ surface and measure its mass, which scientists can only imagine at the moment.

If DART is successful, then it's a first step towards a world capable of defending itself from a future existential threat, the plan said.

If DART is successful, then it is a first step towards a world capable of defending itself from a future existential threat, said planetary scientist Nancy Chabot.

Being prepared

Very few of the billions of asteroids and comets in our solar system are considered potentially dangerous to our planet, and none in the next hundred years.

But “I guarantee you that if you wait long enough, there will be an object,” said Thomas Zurbuchen, chief scientist at NASA.

We know that from the geological record, for example, the six mile wide Chicxulub asteroid hit Earth 66 million years ago, plunging the world into a long winter that led to the mass extinction of dinosaurs along with 75% of species. .

An asteroid the size of Dimorphos, by contrast, would only cause a regional impact, such as devastating a city, albeit with greater force than any nuclear bomb in history.

Scientists also hope to gather valuable new information that can inform them about the nature of asteroids more generally.

The amount of momentum that DART imparts to Dimorphos will depend on whether the asteroid is solid rock or more like a “junk heap” of boulders bound by mutual gravity, a property that is not yet known.

We also don’t know its actual shape – whether it’s more like a dog bone or a donut, but NASA engineers are confident DART’s SmartNav guidance system will achieve its goal.

If it’s missing, NASA will have another chance in two years, with the spaceship containing just enough fuel for another passage.

But if it succeeds, then it’s a first step towards a world capable of defending itself from a future existential threat, Chabot said.

NASA will crash a spacecraft into an asteroid 525 feet wide in September. Here’s how to watch it

© 2022 AFP

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