NASA launched a spacecraft early Wednesday morning that will deliberately crash into an asteroid millions of miles from Earth, the first test of humanity’s ability to divert a potentially catastrophic celestial body.
The Double Asteroid Redirection Test (DART) launched at 1:21 a.m. EST Wednesday from Vandenberg Space Force Base in Southern California. The mission’s purpose is simple in theory: The DART spacecraft will speed up to about 15,000 mph and eventually hurtle itself into a small asteroid, Dimorphos, in late September 2022. The collision will happen about 6.8 million miles from Earth.
NASA will then measure any change in momentum to see if the test successfully altered the asteroid’s trajectory. Dimorphos, which is about two football fields in size, orbits around a much larger asteroid called Didymos, which is about half a mile across.
“What we’re going to try and do is move this asteroid, just change its orbit a little bit and demonstrate that we can actually do this,” Dr. Lori Glaze, director of NASA’s Planetary Science Division, said in a Q&A on Tuesday. “We don’t know of any asteroids that are potentially dangerous right now … but we want to test this technique so that if and when we discover an asteroid … we have this tool in our belt and we are ready to go.”
Neither asteroid poses a threat to Earth, and NASA stressed that there is no known body larger than Dimorphos that has a “significant chance” to hit the planet in the next 100 years. (NASA has a database of near-Earth objects, but only about 40% of those they’ve been tasked with finding have been tracked as part of the agency’s planet defense effort.)
If DART goes as planned, it will help humanity deal with any threatening space object in the future and provide evidence that they can be diverted from a collision course with Earth. Ideally the orbit of Dimorphos around the larger asteroid will shift by a fraction of 1% to shift the orbit of the smaller body by several minutes or more.
In the event of a future threat, such a collision millions of miles from Earth could provide enough time for space programs to shift the trajectory of asteroids so they swoop by us instead.
“This asteroid system is a perfect testing ground to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course should an Earth-threatening asteroid be discovered in the future,” NASA said of the mission.