NASA Alters Asteroid Orbits Around the Sun in Planetary Defense Test

The DART mission marks the first time a human-crafted object has changed the path of a celestial body as it orbits the sun.

Published on Mar. 9, 2026

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In 2022, NASA's DART spacecraft intentionally crashed into the asteroid Dimorphos, part of the binary asteroid system with Didymos. New observations show that the impact permanently decreased the time required for the two asteroids to complete one solar orbit by less than a second, demonstrating the potential to protect Earth from cosmic threats.

Why it matters

The DART mission was a crucial test of planetary defense capabilities, showing that a small change in an asteroid's motion can make the difference between a hazardous object hitting or missing Earth. Understanding how to deflect asteroids on a collision course is an important step in safeguarding our planet.

The details

When DART slammed into Dimorphos, it released a massive cloud of debris estimated at 35.3 million pounds. While Dimorphos only lost 0.5% of its mass, the force of the debris actually packed more of a punch than the spacecraft itself, boosting the momentum of the asteroid system and shrinking its orbit around the sun.

  • In 2022, the DART spacecraft intentionally crashed into the asteroid Dimorphos.
  • The new data on the orbital changes was published in the journal Science Advances on March 9, 2026.

The players

DART

The Double Asteroid Redirection Test, a NASA spacecraft that intentionally crashed into the asteroid Dimorphos in 2022 as part of a planetary defense experiment.

Dimorphos

A 560-foot-wide (170-meter-wide) asteroid that is part of a binary asteroid system with Didymos.

Didymos

A larger asteroid that orbits the sun along with its companion Dimorphos.

Dr. Rahil Makadia

The lead author of the study published in Science Advances, a planetary defense scientist who worked on the DART team and recently completed his PhD in aerospace engineering at the University of Illinois Urbana-Champaign.

Steve Chesley

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

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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.”

— Dr. Rahil Makadia, Planetary defense scientist and lead study author (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, Co-lead author and senior research scientist at 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 of the European Space Agency's Hera mission (Email)

What’s next

The European Space Agency's Hera mission, launched in 2024, will fly by the aftermath of the DART collision later this year and capture the first new images of Dimorphos.

The takeaway

The DART mission's success in altering the orbits of two asteroids around the sun demonstrates the potential of kinetic impact as a technique for defending Earth against asteroid hazards. This breakthrough paves the way for future efforts to identify and deflect potentially dangerous space rocks before they pose a threat to our planet.