Back in the nineties there was a brief fear and fascination with the idea of our planet being struck by a comet or asteroid. Perhaps a group of writers in Hollywood recalled their own classes in elementary where teachers discussed what brought about the end of the Dinosaurs. Either way, we got two movies out of it (Deep Impact and Armageddon) along with the terrifying realization that something from outer space could collide with our planet and that would be the end. “It’s what we call a global killer” says Billy Bob Thornton’s character Dan Truman, in the 1998 Blockbuster, Armageddon.
So what would NASA or the American government do if faced with a real life asteroid impact? Some say that the answer will be to shoot an unmanned ship at the Asteroid and “nudge” it out of Earth’s path. On November 24, 2021, NASA will launch a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California. The mission, which has been named Double Asteroid Redirection Test or DART, is as the name says; a test to see if such a thing is even possible.
NASA has chosen an asteroid called Didymoon (500+ ft wide) that is orbiting a far larger asteroid called Didymos to be the one they test this “kinetic impactor technique” on. They chose the dual asteroids as they are considered to be a “potentially hazardous” Near-Earth-Objects (NEOs). To be considered a threat, an NEO must get within at least 4.5 million miles of Earth. Didymos and its Didymoon came within 3.7 millions miles back in 2003.
Though launch takes place next month, the rocket won’t actually strike Didymoon until October 2, 2022 at an approximate speed of 13,500 miles per hour. Is anyone else getting those story problem flashbacks? If Martin gets on a train at 9:25 am and heads east while traveling 45 mph, and Steve gets on an Westbound train at…
The Daily Mail reports that NASA’s goal with the test isn’t to see if it can blow an asteroid to smithereens, but to “change the speed of Didymoon a fraction of a percent” which “will be enough so NASA can measure its altered orbit.”
Of course the real concern is an asteroid like Bennu which has an uncomfortably small chance of crashing into Earth. Back on August 26th, 2021 the Daily Mail also reported that “Deflecting an asteroid such as Bennu, which has a small chance of hitting Earth in about a century and a half, could require multiple small impacts from some sort of massive human-made deflection device, according to experts.”
According to NASA, Bennu has a 1 in 1,750 chance of making a deep impact into the Earth. (See what I did there? Ha!) So why have we abandoned the whole blow it into smithereens approach? Because experts fear that being struck by dozens, maybe hundreds, of small pieces of an asteroid could be just as catastrophic as being done in by the intact version. So now the idea is to “gently bump” the mass until it is pushed out of our path altogether.
By testing DART and “kinetic impact deflection” (KID) on Didymoon, they can see if it’s plausible to strike it and to see how many more times it would need to be hit.
On Nov. 24 at 1:20am ET, @NASA’s DART mission will launch from @SLDelta30 in California. It will be the first demonstration of the kinetic impactor technique, which involves sending a high-speed spacecraft into the path of an asteroid to change its motion: https://t.co/g01L0LOJ85 pic.twitter.com/T0JmRVQs0A
— NASA's Kennedy Space Center (@NASAKennedy) October 6, 2021
To learn as much as you can about DART, check out NASA’s own page devoted specifically to the mission.