NASA to smash spacecraft into asteroid as strategy to safeguard Earth from hazardous space bodies takes shape
A gigantic asteroid is set to zip by our planet on April 29, and while it poses no threat as of now, it is big enough to leave a six-mile wide crater and darken the atmosphere with dust if it does hit the Earth at some point. The 1998 OR2 is at least a mile wide and will pass within four million miles of our planet - meaning it's close enough to be classified by NASA as "potentially hazardous," considering it will continue to make close passes to Earth as both bodies revolve around the sun.
Amy Mainzer of the University of Arizona and one of the leading scientists in asteroid detection and planetary defense told National Geographic that it's "just a whopping big asteroid."
"It’s smaller than the thing thought to have caused the extinction of the dinosaurs, but it is easily capable of causing a lot of damage," she said.
But asteroids passing relatively close to our planet is a common phenomenon. Dozens of these — some big enough to cause massive regional and continental destruction — pass within five million miles of Earth every year.
At some point in our future as a species, Earth will most certainly be threatened by a space rock large enough to take out civilizations — and so it only makes sense to have a plan in place for protecting the planet. And so NASA is launching a spacecraft next year to carry out the first test of a strategy to stop a specicidal asteroid by hitting it while it's still far enough to alter its orbital course.
As part of the Double Asteroid Redirection Test (DART), a spacecraft will be launched into the smaller of two asteroids orbiting each other. Even if there is a slight change in the smaller object's orbit, it will be a decisive indicator to gauge whether it has been deflected successfully.
Ed Lu, a retired NASA astronaut, told the outlet it's "an exciting time" in human space exploration.
“I think DART’s going to be a tremendous demonstration," he said.
With that said, the first step to deflecting a menacing asteroid is locating it.
“There are literally hundreds of thousands of asteroids out there, and we want to separate out those we should keep a closer watch on and monitor over time,” NASA’s planetary defense officer Lindley Johnson told the outlet.
The 1998 OR2 will pass within four million miles of our planet traveling at nearly 20,000 miles per hour. While it will zip by roughly 16 times farther than the moon, the asteroid will continue its 3.7-year orbit around the sun and circle back inside Earth's orbit with each revolution, getting closer every time. In 2078, astronomers predict it will swing within about a million miles of Earth.
“We don’t want to get hit by something that big,” Johnson said. “Our most important task is finding them and getting a fuller catalog of everything that’s out there, so we don’t get surprised.”
The DART mission, which will test one strategy by slamming a half-ton spacecraft into an approaching asteroid, is scheduled to launch in July 2021.
The refrigerator-sized spacecraft will approach a half-mile wide asteroid called "Didymos" in October 2022 at a distance of seven million miles from Earth.
Didymos is orbited by a 500-foot wide moonlet affectionately called the "Didymoon" — which is DART's primary target. The effects of the impact in terms of changes in the duration of its orbit around Didymos will be measured by ground-based telescopes.
“If it wasn’t a binary, it would be basically impossible to measure with high precision,” Megan Bruck Syal of Lawrence Livermore National Laboratory told National Geographic. ”This is a remarkable opportunity to test the effectiveness of the kinetic impactor technology on a real asteroid.”
Hold on, it gets better.
Just moments before DART smashes into Didymoon at a whopping 14,700 miles an hour, a shoebox-sized camera will be released from the spacecraft to watch the impact, the subsequent spray of debris, and possibly even the resulting crater.
According to Johnson, the collision could decrease the moonlet's 12-hour orbit by as much as seven minutes — although a change of just 70 seconds will be considered a major success.
“By changing the orbit of the moon, we don’t change the orbit of [Didymos],” Johnson explained. “Didymos is a potentially hazardous asteroid, so we don’t really want to affect its orbit. We don’t want to accidentally push it the wrong direction.”
Nancy Chabot, a planetary scientist at Johns Hopkins University's Applied Physics Laboratory and project scientist for DART, told Space.com last year that it's going to take years of observation and experiments to be able to effectively divert asteroids away from the Earth
"To do something like this, we'd also need a really long warning time; the idea of a kinetic impactor is definitely not like [the movie] 'Armageddon,' where you go up at the last hour and you know, save the Earth," Chabot said.
"This is something that you would do five, 10, 15, 20 years in advance — gently nudge the asteroid so it just sails merrily on its way and doesn't impact the Earth," she added.