NASA has announced preliminary results from the Double Asteroid Redirection Test (DART) mission, which successfully smashed into the asteroid Dimorphos several weeks ago. Now, the mission is successful in more ways than one — NASA would have been happy with altering the space rock’s orbit by a few seconds, but DART beat that standard by a factor of 25.
This marks the first time humanity has altered the course of a celestial object, even if it was a rather small one. Dimorphos is about 170 meters in diameter, but it orbits a larger asteroid known as Didymos. This binary system made for a perfect test of planetary defense technology as any change in Dimorphos’ orbit would be easily discernible.
DART intersected with Dimorphos on Sept. 26. While the probe was only about the size of a vending machine, it impacted the surface at 14,000 miles per hour (22,530 kilometers per hour). Before the impact, NASA set a benchmark of 73 seconds as the minimum viable change in orbit. Dimorphos had its orbit shifted from 11 hours and 55 minutes to 11 hours and 23 minutes — a difference of 32 minutes and 25 times more than initially hoped.
This imagery from NASA’s Hubble Space Telescope shows the debris tail 285 hours after DART’s impact.
The team is still gathering data that may refine our understanding of Dimorphos’ orbit, which could change the current estimate by up to two minutes in either direction. Regardless, this opens the door to deflecting a potentially dangerous asteroid by hitting it with a super-fast impactor. “NASA has proven we are serious as a defender of the planet. This is a watershed moment for planetary defense and all of humanity, demonstrating commitment from NASA’s exceptional team and partners from around the world,” says NASA Administrator Bill Nelson.
Multiple telescopes, including Hubble and the new James Webb Space Telescope, were watching the event to see how much material was ejected from Dimorphos. Early analysis says “a lot.” In the days following the impact, Dimorphos grew a comet-like tail due to the impact. NASA is still investigating the ejecta, which will be aided by more data on the composition of Dimorphos. It has the LICIACube satellite that traveled to Dimorphos and Didymos with DART, but the European Space Agency (ESA) will have more to say in about four years. That’s when the ESA’s Hera probe will reach Dimorphos. It will conduct observations of both Dimorphos and Didymos, paying particular attention to the crater left by DART.
Now read:
- NASA’s DART Asteroid-Smasher Is Gone, But We’ll Always Have These Stunning Images of Its Demise
- NASA’s DART Craft Could Leave Asteroid ‘Unrecognizable’: Study
- Images of DART Impact Show the Differences Between Webb and Hubble
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