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The Asteroid Double Redirection test succeeded in altering the trajectory of the asteroid Dimorphos when the NASA spacecraft intentionally rammed into space rock Sept. 26, according to the agency.
The DART mission, a large-scale demonstration of deflection technology, was the first in the world conducted in the name of planetary defense. The mission was also the first time humanity had intentionally altered the motion of a celestial object in space.
Before impact, it took Dimorphos 11 hours and 55 minutes to orbit its larger parent asteroid Didymos. Astronomers used ground-based telescopes to measure how Dimorphos’ orbit changed after impact.
Now it takes 11 hours and 23 minutes for Dimorphos to circumnavigate Didymos. The DART spacecraft changed its orbit by 32 minutes.
Initially, astronomers expected DART to be a success if it shortened the trajectory by 10 minutes.
“We all have a responsibility to protect our planet. After all, it’s the only one we have,” NASA Administrator Bill Nelson said.
“This mission shows that NASA is trying to be ready for whatever the universe throws at us. NASA has proven that we are serious about defending the planet. This is a watershed moment for planetary defense and all humanity, demonstrating the commitment of NASA’s exceptional team and its partners around the world.
Neither Dimorphos nor Didymos pose a threat to Earth, but the twin asteroid system was a perfect target to test deflection technology, according to the DART team.
“For the first time ever, humanity has altered the orbit of a planetary object,” said Lori Glaze, director of NASA’s planetary science division.
“As new data arrives daily, astronomers will be able to better assess if, and how, a mission like DART could be used in the future to help protect Earth from collision with a asteroid if we ever find one heading our way.”
The DART team continues to collect data observing the twin asteroid system and orbital measurement may become more accurate in the future.
The team is now focusing on measuring the momentum transferred from DART to Dimorphos. At the time of impact, the spacecraft was moving at approximately 14,000 miles per hour (22,530 kilometers per hour). Astronomers will analyze the amount of rocks and dust thrown into space after the impact.
The DART team believe the recoil of the plume “significantly enhanced” the spacecraft’s thrust against the asteroid, much like the release of air from a balloon propels it in the opposite direction, according to NASA.
Astronomers are still studying the surface of Dimorphos and its weakness or strength. The DART team’s first look at Dimorphos, provided by DART before the crash, suggests the asteroid is a pile of rubble held together by gravity.
“DART has provided us with fascinating data on the properties of asteroids and the effectiveness of a kinetic impactor as a planetary defense technology,” said Nancy Chabot, DART coordination manager of the University’s Applied Physics Laboratory. Johns Hopkins in Laurel, Maryland. “The DART team continues to work on this rich dataset to fully understand this first planetary defense test of asteroid deflection.”
Imagery continues to return from the Light Italian CubeSat for Imaging of Asteroids, or LICIACube, which was provided by the Italian Space Agency and accompanied as a robotic photojournalist on the DART mission.
In about four years, the European Space Agency’s Hera mission will also fly over the twin asteroid system to study the crater left by the collision and measure the mass of Dimorphos.