New findings reveal that the 2022 DART collision not only decreased the orbit of the moon Dimorphos around its parent asteroid Didymos but also subtly altered the trajectory of the entire binary asteroid system around the sun.
This artist’s illustration depicts a cloud of debris ejected after NASA’s DART spacecraft collides with the asteroid Dimorphos. Image credit: ESO/M. Kornmesser.
During the NASA DART mission, the collision with Dimorphos generated a massive cloud of rock debris and altered the shape of the 170-meter (560-foot) asteroid.
This debris not only escaped but also provided Dimorphos with an explosive thrust—what scientists refer to as a momentum enhancer.
The momentum enhancement factor from the DART impact was approximately 2, indicating that the spacecraft’s impact was effectively doubled due to the debris expelled.
Previous studies have determined that the moon’s 12-hour orbit around the 805-meter-wide Didymos was shortened by 33 minutes.
The latest research indicates that the collision ejected so much material from the binary asteroid system that it even modified the binary star’s 770-day orbital period around the sun by 0.15 seconds.
Dr. Rahil McAdia from the University of Illinois at Urbana-Champaign stated, “The change in the orbital velocity of the binary system was about 11.7 microns per second, or 1.7 inches per hour.”
“Over time, even minor adjustments in an asteroid’s motion can influence the likelihood of a dangerous object colliding with Earth.”
To demonstrate the DART mission’s measurable influence on the binary star system, the researchers meticulously tracked DART’s solar orbit.
In addition to radar and ground-based asteroid observations, they monitored stellar occultations—events where an asteroid passes directly in front of a star, briefly blocking its light.
This method enables precise measurements of the asteroid’s speed, shape, and position.
The research team relied on volunteers worldwide who observed 22 stellar eclipses between October 2022 and March 2025.
“These stellar occultation observations, combined with years of existing data, were essential in calculating how DART altered Didymos’s orbit,” said Dr. Steve Chesley from NASA’s Jet Propulsion Laboratory.
“This research is highly dependent on weather conditions, often requires travel to remote areas, and success is not guaranteed.”
“This breakthrough would not have been possible without the unwavering support of numerous volunteer observers globally.”
Analyzing Didymos’ motion also enabled scientists to ascertain the density of both asteroids.
Dimorphos was found to be slightly less dense than previously estimated, aligning with the theory that it formed from rock fragments shed by the rapidly rotating Didymos.
This loose material eventually coalesced, creating what is known as a “rubble pile” asteroid, Dimorphos.
Our findings indicate that targeting secondary asteroids in binary systems could be a viable strategy for deflecting kinetic impacts and enhancing planetary defense.
Dr. Preity Cowan from the University of Auckland remarked, “The DART mission proved to be a triumph. An asteroid system deemed safe for Earth was meticulously chosen, allowing NASA to impact the small satellite, leading to a faster orbit around its parent asteroid.”
“This new analysis unveils even more stunning and safe outcomes.”
“The combination of the spacecraft’s impact and the resulting ‘shock’ from the ejected material from the satellite was enough to visibly alter the binary star system’s path around the sun.”
“These adjustments may seem trivial, but in terms of trajectory, even minor changes, particularly if applied early on, can have significant repercussions.”
This milestone is crucial for developments in planetary defense,” said Professor Roberto Armelin from the University of Auckland.
“In a genuine hazardous scenario, small adjustments implemented promptly could prevent a potentially dangerous asteroid from colliding with Earth.”
The next phase is ESA’s Hera mission, set to launch in 2024, which will visit the Didymos system to measure its crater, asteroid mass and structure, and the efficiency of the impact.
“These measurements will aid in transitioning this historic experiment into a reliable planetary defense technology.”
For more information, check the result published in Scientific Progress.
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Rahil Makadia et al. 2026. Direct Detection of Geocentric Deflections of Asteroids: Didymos System After DART. Scientific Progress 12 (10): 10.1126/sciadv.aea4259
Source: www.sci.news
