NASA's DART Mission Alters Asteroid's Solar Orbit

NASA's Double Asteroid Redirection Test (DART) mission, which intentionally impacted the asteroid moonlet Dimorphos in September 2022, has been found to have altered not only Dimorphos' orbit around its larger companion, Didymos, but also their combined orbit around the Sun. This marks the first time a human-made object has measurably changed the trajectory of a celestial body in the solar system.

The DART spacecraft collided with Dimorphos, a 560-foot-wide (170-meter-wide) asteroid, resulting in a significant amount of debris being ejected into space. This impact not only shortened Dimorphos' orbit around Didymos by 33 minutes but also caused a slight change in the binary system's orbit around the Sun. The orbital period around the Sun was altered by approximately 0.15 seconds, a change that, while minuscule, demonstrates the potential of kinetic impactors in planetary defense strategies.

Thomas Statler, lead scientist for solar system small bodies at NASA Headquarters, emphasized the significance of this finding:

"This is a tiny change to the orbit, but given enough time, even a tiny change can grow to a significant deflection."

The study detailing these findings was published in the journal Science Advances. Researchers utilized data from stellar occultations—events where an asteroid passes in front of a star, causing a brief dimming—to obtain precise measurements of the asteroid's position, speed, and shape. These observations were made possible by volunteer astronomers worldwide, who recorded 22 such events between October 2022 and March 2025.

The success of the DART mission provides a valuable data point for developing strategies to protect Earth from potential asteroid threats. The mission was managed by the Johns Hopkins Applied Physics Laboratory for NASA's Planetary Defense Coordination Office.