A spacecraft will deliberately crash into an asteroid at 14,000 miles per hour on Monday in what will be the very first test of a planetary defense strategy to alter the trajectories of dangerous space rocks that could one day collide with Earth.
Launched in 2021, NASA’s Double Asteroid Redirection Test (DART) is now closing in on a half-mile-wide asteroid called Didymos, which is orbited by an even smaller asteroid called Dimorphos, or “Didymoon.”
DART is scheduled to slam into Dimorphos, which is about 400-feet-wide, at 7:14pm ET on Monday, concluding its mission with a kinetic impact maneuver that is expected to slightly shift the path of the moonlet around Didymos. NASA will livestream coverage of the impact at the link below, starting at 6pm ET.
“Up until now, we haven’t had too many options for what we might do if we found something that was incoming,” said Andy Rivkin, a planetary astronomer at the Johns Hopkins University Applied Physics Laboratory and the investigation team lead for DART, in an interview with VICE News.
“DART is the first test of how we might be able to deflect something without having to resort to a nuclear package, or sitting in our basements, waiting it out, and crossing our fingers,” he added.
The Didymos system is not a threat to Earth, as it passes some 3.7 million miles from our planet at its closest point. There is also no risk that DART will inadvertently nudge the asteroids into a new trajectory that is hazardous to Earth. The space probe is expected to shorten Dimorphos’ orbit by about 1 percent, causing it to lose about four minutes from its current period of 11.9 hours, but it will leave the rock intact and snugly in orbit around Didymos.
Though the shift may seem small, it would be enough to divert an asteroid that was headed to Earth, if a similar mission were launched far enough in advance. The impact and aftermath will also be big enough to be captured by ground and space observatories, including the Hubble Space Telescope and the James Webb Space Telescope, both of which will be watching the events unfold.
There will be many close-ups of the unprecedented crash, in addition to the long-distance views. As it approaches its target, DART will stream images of its final moments at a rate of one per second with an onboard instrument called the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO).
Meanwhile, a shoebox-sized space probe called the Light Italian CubeSat for Imaging of Asteroids (LICIACube) will take pictures of the crash from a distance of about 34 miles during a flyby of the asteroid system. Built by the Italian Space Agency, LICIACube has traveled with DART most of the way to Didymos, until it separated from the spacecraft two weeks ago in preparation for Monday’s photoshoot.
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Some images from DRACO should be available during the livestream of the crash, though it may take weeks or months for the DART team to receive the best pictures from LICIACube, and all the other telescopes that will be watching the unprecedented event. We will even get another close look at the crash site in a few years, when the European Space Agency’s Hera probe is scheduled to visit the system to study the fallout of the impact.
All of these unique perspectives on this epic wipeout in outer space will help scientists unravel mysteries about asteroids, including how to prevent them impacting our planet. It is extremely unlikely that we will be hit by the kind of space rock that killed off the dinosaurs anytime soon, but even a much smaller asteroid could be extremely dangerous on a regional level.
Regardless of the odds, it never hurts to have a plan for such an apocalyptic possibility. The fact that it involves punching an asteroid with a space probe is just a bonus.