DART mission successfully changed motion of an asteroid

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The Double Asteroid Redirection Test successfully changed the trajectory of the asteroid Dimorphos when the NASA spacecraft intentionally slammed into the space rock on September 26, according to the agency.

The DART mission, a full-scale demonstration of deflection technology, was the world’s first conducted on behalf of planetary defense. The mission was also the first time humanity intentionally changed the motion of a celestial object in space.

Prior to 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 Dimorphos 11 hours and 23 minutes to circle 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.

The Hubble Space Telescope captured an image of debris blasted away from the surfacce of Dimorphos 285 hours after impact on October 8.

“All of us have a responsibility to protect our home planet. After all, it’s the only one we have,” said NASA Administrator Bill Nelson.

“This mission shows that NASA is trying to be ready for whatever the universe throws at us. 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.”

Neither Dimorphos nor Didymos pose a threat to Earth, but the double-asteroid system was a perfect target to test deflection technology, according to the DART team.

“For the first time ever, humanity has changed the orbit of a planetary object,” said Lori Glaze, director of the Planetary Science Division at NASA.

“As new data come in each day, astronomers will be able to better assess whether, and how, a mission like DART could be used in the future to help protect Earth from a collision with an asteroid if we ever discover one headed our way.”

The DART team continues to gather data by observing the double-asteroid system and the orbital measurement may become more precise in the future.

The team is now focusing on measuring how much momentum was transferred from DART to Dimorphos. At the time of impact, the spacecraft was moving at about 14,000 miles per hour (22,530 kilometers per hour). Astronomers will analyze the amount of rocks and dust blasted into space after impact.

The DART team believes that the recoil from the plume “substantially enhanced” the spacecraft’s push against the asteroid, not unlike the release of air from a balloon propels it in the opposite direction, according to NASA.

Astronomers are still investigating the surface of Dimorphos and how weak or strong it is. The DART team’s first look at Dimorphos, provided by DART before the crash, suggests that the asteroid is a pile of rubble held together by gravity.

“DART has given us some fascinating data about both asteroid properties and the effectiveness of a kinetic impactor as a planetary defense technology,” said Nancy Chabot, the DART coordination lead from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “The DART team is continuing 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 tagged along as a robotic photojournalist on DART’s mission.

In about four years, the European Space Agency’s Hera mission will also fly by the double-asteroid system to study the crater left by the collision and measure the mass of Dimorphos.

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