No, this isn’t a remake of a terrible and scientifically inaccurate 90s film, NASA is actually planning on changing the trajectory of an asteroid in orbit in 2022.
NASA’s Double Asteroid Redirection Test (DART) mission will launch between December 2020 and May 2021, and rendezvous with a small asteroid in October 2022 to throw it slightly off course, in a demonstration of what is currently the only viable option for protecting Earth from an asteroid.
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According to Business Insider:
The asteroid in question, informally known as Didymoon, is a moon asteroid about 150 meters tall. It’s part of a double asteroid system — named after the Greek word for twins, Didymos — in which it orbits another 800-meter asteroid about a kilometer away.
The binary nature of the system is also a feature, not a bug.
“A binary asteroid is the perfect natural laboratory for this test,” said Tom Statler, program scientist for DART at NASA Headquarters. “The fact that Didymos B is in orbit around Didymos A makes it easier to see the results of the impact, and ensures that the experiment doesn’t change the orbit of the pair around the sun.”
In the same press release, NASA’s planetary defense officer (how cool of a title is that?!) Lindley Johnson said:
DART would be NASA’s first mission to demonstrate what’s known as the kinetic impactor technique — striking the asteroid to shift its orbit — to defend against a potential future asteroid impact. This approval step advances the project toward an historic test with a non-threatening small asteroid.
NASA also shared this animation of what will happen once DART reaches the Didymos system. It’s rather straightforward – go very fast, point DART at the right rock, and let physics do its thing.
That little impact isn’t as little as it looks. The spacecraft weighs about 500 kilograms and is moving at six kilometers a second. That should change the orbital velocity of the asteroid by 0.4 millimeters per second. That should result in a big change in the orbit over time.
“DART is a critical step in demonstrating we can protect our planet from a future asteroid impact,” said Andy Cheng, who works at the Johns Hopkins Applied Physics Laboratory and coleads the DART investigation. “Since we don’t know that much about their internal structure or composition, we need to perform this experiment on a real asteroid. With DART, we can show how to protect Earth from an asteroid strike with a kinetic impactor by knocking the hazardous object into a different flight path that would not threaten the planet.”
Of course, this is all small-scale. NASA is particularly interested in asteroids that are over 1 kilometer in diameter, as these space rocks are the ones that could cause a large amount of damage globally.
NASA explains more: To assess and formulate capabilities to address these potential threats, NASA established its Planetary Defense Coordination Office (PDCO) in 2016, which is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting plans and coordination of U.S. government response to an actual impact threat.
It feels like a lifetime ago, but most of us will remember the Chelyabinsk meteor over Russia in 2013. Moving at 19 kilometers each second, the 12,000 metric ton chunk of rock blasted into the atmosphere, and due to its shallow angle, exploded in midair, shattering windows and creating some truly awesome videos.
Despite weighing more than the Eiffel Tower, the Chelyabinsk meteor was undetected prior to entering our atmosphere. While around 1500 people were injured by it, thanks to it exploding as an air burst, there were no deaths or major damage done.
There’s also a hypothesis for what NASA is calling a “gravity tractor.” This method of planetary protection would use the spacecraft’s own gravity, alongside the target asteroid, to ever-so-slightly adjust the asteroid’s orbit over the course of years or even decades.
Other possible methods involve shooting light at the asteroid, which would act as a solar sail to nudge it off course. There’s also an idea of landing on the asteroid and then adding propulsion, but the downside to this is the difficulty with actually landing safely on the asteroid, and even then you’re highly unlikely to be on or near the center of mass for the rock.
But if you’re worried about a potential asteroid impact, well… Don’t. NASA has a rather thorough FAQ regarding their planetary protection program, but the likelihood of a large asteroid impacting Earth is extremely low. But then again, that’s not a zero chance.
Cover image via iStockphoto
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