Space Science

NASA's Dart spacecraft slams into asteroid in planetary defense test

The 1,260-pound craft collided with the asteroid Dimorphos, a successful demonstration of a mitigation technique that could be used in the future to deflect asteroids that pose a threat to Earth.

October 5, 2022
The Scitech

NASA/ Johns Hopkins APL

After 10 months flying in space, NASA's Double Asteroid Redirection Test, or DART, the world's first planetary defense technology demonstration, successfully impacted its asteroid target on Monday (September 26) —the agency's first attempt to move an asteroid in space.

Mission control at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, announced the successful impact at 7:14 p.m. EDT.

As a part of NASA's overall planetary defense strategy, DART's impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.

"At its core, DART represents an unprecedented success for planetary defense, but it is also a mission of unity with a real benefit for all humanity," NASA Administrator Bill Nelson said. "As NASA studies the cosmos and our home planet, we're also working to protect that home, and this international collaboration turned science fiction into science fact, demonstrating one way to protect Earth."

DART targeted the asteroid moonlet Dimorphos, a small body just 530 feet (160 meters) in diameter. It orbits a larger, 2,560-foot (780-meter) asteroid called Didymos. Neither asteroid poses a threat to Earth.

The mission's one-way trip confirmed NASA can successfully navigate a spacecraft to intentionally collide with an asteroid to deflect it, a technique known as kinetic impact.

"This first-of-its-kind mission required incredible preparation and precision, and the team exceeded expectations on all counts," APL Director Ralph Semmel said. "Beyond the truly exciting success of the technology demonstration, capabilities based on DART could one day be used to change the course of an asteroid to protect our planet and preserve life on Earth as we know it."

The investigation team will now observe Dimorphos using ground-based telescopes to confirm that DART's impact altered the asteroid's orbit around Didymos. Researchers expect the impact to shorten Dimorphos' orbit by about 1%, or roughly 10 minutes. Precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

The spacecraft's sole instrument, the Didymos Reconnaissance and Asteroid Camera for Optical navigation, or DRACO, together with a sophisticated guidance, navigation, and control system that works in tandem with Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav) algorithms, enabled DART to identify and distinguish between the two asteroids, targeting the smaller body.

These systems guided the 1,260-pound box-shaped spacecraft through the final 56,000 miles of space into Dimorphos, intentionally crashing into it at roughly 14,000 miles per hour to slightly slow the asteroid's orbital speed. DRACO's final images, obtained by the spacecraft seconds before impact, revealed the surface of Dimorphos in close-up detail.

"What a remarkable day for humanity," said APL Space Exploration Sector Head Bobby Braun. "The team nailed it—and I couldn't be more proud of their efforts. Data from this test will inform future planetary defense efforts. Today is a milestone in demonstrating just how far our nation's space program has come, and how important it is to all of us here on Earth."

With the asteroid pair within 7 million miles of Earth, a global team is using dozens of telescopes stationed around the world and in space to observe the asteroid system. Over the coming weeks, they will characterize the ejecta produced and precisely measure Dimorphos' orbital change to determine how effectively DART deflected the asteroid. The results will help validate and improve scientific computer models critical to predicting the effectiveness of this technique as a reliable method for asteroid deflection.

Johns Hopkins APL manages the DART mission for NASA's Planetary Defense Coordination Office as a project of the agency's Planetary Missions Program Office.

Source: Johns Hopkins University news release