NASA Will Attempt to Knock Asteroid Out of Orbit to Test Planetary Defenses
By R.J. Johnson - @rickerthewriter
February 6, 2019
The headline sounds like something out of a science fiction novel, but scientists really are about to conduct the first test of a planetary defense system designed to knock near-Earth asteroids away from our planet.
While large, planet-ending asteroids are incredibly rare and unlikely to strike the planet anytime soon, smaller asteroids are a concern. One example is the Feb. 2013, Chelyabinsk meteor that entered the atmosphere over Russia. The nearly 13,000 ton object exploded in an air burst over Chelyabinsk Oblast, creating a blast equivalent to 400-500 kilotons of TNT or nearly 33 times as much energy released by the atomic bomb that detonated at Hiroshima.
A larger object could do even more damage to entire cities or even countries. Fortunately, the folks at NASA and the European Space agency are teaming up for a new mission named The Double Asteroid Redirect Test (or DART).
The project aims to knock an asteroid off course by slamming into it using a special probe traveling at around 4 miles per second. DART is targeting an asteroid dubbed "Didymos" and its smaller counterpart, "Didymoon," in an effort to "punch" the smaller rock off course. "Smaller" is a bit deceptive as Didymoon is about the size of the Pyramid of Giza. That might not sound like much, but if an asteroid that size were to impact Earth at around 19 miles a second (the average speed of asteroids), scientists say that could potentially destroy a city and wreck and entire region.
Neither asteroid poses any kind of threat to Earth and the course adjustment won't put it on any kind of trajectory to hit earth. Both asteroids are located about seven million miles away from Earth, making them the perfect test subjects.
"This isn’t the first spacecraft impact into a planetary body,” Hera’s lead scientist Patrick Michel, CNRS Director of Research of France’s Côte d'Azur Observatory said. “NASA’s Deep Impact crashed into comet Tempel 1 in 2005, but not to try and deflect it, instead it was to expose subsurface material – the 6-km diameter body was much too large. But Didymoon is small enough, and in a tight enough 12-hour orbit around its parent, that its orbital period can indeed be shifted in a measurable way."
NASA released a video simulation of the experiment to give you an idea of what they're trying to do.
Didymoon will also be the smallest asteroid ever visited by a probe.
NASA is set to launch the DART mission by 2021 with the impact expected to smack into the smaller asteroid in October 2022. After that, an ESA probe will launch toward Didymos and Didymoon to observe the pair of asteroids and see how much momentum was transferred to the rocks by NASA's probe.
"We will better understand whether this technique can be used even for larger asteroids, giving us certainty we could protect our home planet if needed," ESA’s Hera project scientist Michael Küppers explained in a statement.
Of course, if this doesn't work, there's always Bruce Willis and Ben Affleck to help knock the asteroid off-course.
Photo: Getty Images