NASA's DART Mission Successfully Alters Asteroid Orbit

New data shows the aftermath of the first human-caused change to a celestial body's orbit around the sun.

Mar. 10, 2026 at 7:11pm

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In 2022, NASA's DART spacecraft intentionally collided with the asteroid Dimorphos, which orbits the larger asteroid Didymos, in a planetary defense test. New observations reveal that the collision permanently decreased the time it takes for Didymos and Dimorphos to complete one solar orbit by less than a second. This small change in the asteroids' motion could make the difference between a hazardous object hitting or missing Earth in the future.

Why it matters

The DART mission marks the first time a human-made object has altered the path of a celestial body as it orbits the sun. This successful test of a kinetic impactor technique demonstrates a potential method for protecting Earth from future asteroid threats, as even a small change in an asteroid's motion can prevent a collision.

The details

When DART slammed into Dimorphos, it released a massive cloud of debris estimated at 35.3 million pounds, which was 30,000 times greater than the spacecraft's mass. This debris release actually packed more of a punch than the spacecraft itself, providing a momentum boost that shrank the time it takes for the pair of asteroids to orbit the sun by 0.15 seconds. Astronomers relied on ground-based observations, including challenging stellar occultation measurements, to precisely calculate this orbital change.

  • In late 2024, the Atlas near-Earth asteroid survey discovered an asteroid with a 2% chance of hitting Earth in 2032.
  • In 2022, the DART spacecraft intentionally collided with the asteroid Dimorphos.
  • Between October 2022 and March 2025, volunteer astronomers around the world conducted 22 stellar occultation observations to measure the orbital changes of the Didymos-Dimorphos system.

The players

DART

The Double Asteroid Redirection Test, a NASA spacecraft that intentionally collided with the asteroid Dimorphos in 2022 to test a kinetic impactor technique for planetary defense.

Dimorphos

A 560-foot-wide asteroid that orbits the larger asteroid Didymos, serving as the target for the DART mission.

Didymos

A binary asteroid system that includes Dimorphos, providing NASA with a scenario to evaluate how effectively a spacecraft could be used as a deflective tool.

Rahil Makadia

A planetary defense scientist who worked on the DART team and recently completed his Ph.D. in aerospace engineering at the University of Illinois Urbana-Champaign.

Steve Chesley

A senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and a co-lead author of the study on the DART mission's impact.

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What they’re saying

“The change in the binary system's orbital speed was about 11.7 microns per second, or 1.7 inches per hour. Over time, such a small change in an asteroid's motion can make the difference between a hazardous object hitting or missing our planet.”

— Rahil Makadia, Planetary defense scientist (Science Advances)

“When combined with years of existing ground-based observations, these stellar occultation observations became key in helping us calculate how DART had changed Didymos' orbit. This work is highly weather-dependent and often requires travel to remote regions with no guarantee of success. This result would not have been possible without the dedication of dozens of volunteer occultation observers around the world.”

— Steve Chesley, Senior research scientist, NASA's Jet Propulsion Laboratory (Science Advances)

“We knew that such a tiny change could occur, which poses no risk to the Earth, but actually measuring it was another challenge that the team tackled extremely well. Doing so requires a well-organized international coordination because one needs to time precisely the blinks caused by the passage of an asteroid in front of a star, as seen by different observers across the planet. If this is done correctly, as in this study, then one can perform measurements at incredible accuracy.”

— Patrick Michel, Principal investigator, European Space Agency's Hera mission (Email)

“The team's amazingly precise measurement again validates kinetic impact as a technique for defending Earth against asteroid hazards and shows how a binary asteroid might be deflected by impacting just one member of the pair.”

— Thomas Statler, Lead scientist for solar system small bodies, NASA (Science Advances)

What’s next

The European Space Agency's Hera mission, launched in 2024, will fly by the aftermath of the DART collision and capture the first new images of Dimorphos later this year. Additionally, NASA's Near-Earth Object Surveyor mission, currently in development, could help spot dark, risky asteroids that have remained nearly invisible from Earth-based observatories.

The takeaway

The DART mission's successful demonstration of a kinetic impactor technique for altering an asteroid's orbit validates this approach as a potential method for protecting Earth from future asteroid threats. Even a small change in an asteroid's motion, like the less-than-one-second decrease in the Didymos-Dimorphos system's orbital period, could make the difference between a hazardous object hitting or missing our planet.