I bet dinosaurs wish they’d thought about that.
On Monday, NASA will attempt a feat humanity has never accomplished before: deliberately smashing a spacecraft into an asteroid to twist its orbit slightly, in a major test of our ability to prevent cosmic bodies from destroying life on Earth.
The Double Asteroid Redirection Test (DART) spacecraft was launched from California last November and is fast approaching its target, which it will hit at nearly 14,000 mph (23,000 km/h).
Neither the lunar asteroid Demorphos nor its orbiting big brother, called Didymus, pose any threat since the pair orbit the Sun, passing about seven million miles from Earth at their closest.
But this experiment was deemed important by NASA to do before the actual need was discovered.
“This is an exciting time not just for the agency but in space history and in human history, quite frankly,” Lindley Johnson, NASA’s planetary defense officer, told reporters at a Thursday briefing.
If all goes as planned, the collision between the car-sized spacecraft and the 530-foot-high asteroid (160 meters or two statues of Liberty) should occur on September 26 at 7:14 p.m. ET (2314 GMT) , and can be watched live on NASA.
By hitting Demorphos directly, NASA hopes to push it into a smaller orbit, reducing ten minutes from the time it takes to encircle Didymus, which is currently 11 hours and 55 minutes — a change that will be detected by ground-based telescopes in the days that follow.
The proof-of-concept experiment will make true what has been experienced before only in science fiction – especially films like “Armageddon” and “Don’t Look Up.”
As the craft moves through space, flying autonomously for the mission’s final stage like a self-guided missile, the main camera system, called DRACO, will begin sending the first images of the Dimorphos.
“It will start out as a small point of light, then eventually it will be magnified and fill the entire field of view,” Nancy Chabot of the Johns Hopkins Applied Physics Laboratory (APL), which hosts the mission console, said in a recent briefing. .
“These images will continue until that doesn’t happen,” the planetary scientist added.
Minutes later, a toaster-sized satellite called LICIACube, which separated from DART two weeks ago, will pass close to the site to capture images of the impact and ejection — the crushed rocks thrown out by the impact.
A LICIACube image will be sent in the following weeks and months.
Watching the action, too: An array of telescopes, both on Earth and in space — including the recently operated James Webb — that might be able to see a bright cloud of dust.
Finally, a full picture of what the system looks like will be revealed when an ESA mission four years later arrives on the line called Hera to survey the surface of Dimorphos and measure its mass, which scientists can only guess at for now.
Very few billions of asteroids and comets in our solar system are considered a potential danger to our planet, and none in the next 100 years or so.
“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 asteroid Chicxulub hit Earth 66 million years ago, plunging the world into a long winter that led to the mass extinction of the dinosaurs with 75% of species.
By contrast, an asteroid the size of Demorphos would only cause a regional impact, such as destroying a city, albeit with more force than any nuclear bomb in history.
Scientists also hope to gather valuable new information that can inform them about the nature of asteroids in general.
The amount of momentum DART imparts to Demorphos depends on whether the asteroid is solid rock, or more like a “garbage pile” of rock bound by mutual gravity, a property that is not yet known.
We also don’t know what it actually looks like: whether it looks like a dog bone or a doughnut, but NASA engineers are confident that DART’s SmartNav guidance system will hit its target.
If you get it wrong, NASA will have another chance in two years, as the spaceship has just enough fuel for another pass.
But if it succeeds, it is a first step toward a world capable of defending itself from an existential threat in the future, Chabot said.
A NASA spacecraft will collide with a 525-foot-wide asteroid in September. Here’s how to watch it
© 2022 AFP
the quote: NASA prepares to deflect asteroid, in major planetary defense test (2022, Sept 23) Retrieved September 23, 2022 from https://phys.org/news/2022-09-nasa-gears-deflect-asteroid-key.html
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