NASA's DART Mission Physically Altered Asteroid Moon's Shape

NASA’s Double Asteroid Redirection Test (DART) mission, launched in 2022, has yielded unexpected results that go beyond its initial objective. Originally aimed at testing whether a spacecraft could alter an asteroid’s trajectory, the mission has revealed that the impact with the asteroid moon Dimorphos significantly changed not only its orbit but also its shape.

Two years ago, NASA’s DART spacecraft deliberately collided with Dimorphos, a small moon orbiting the larger asteroid Didymos. The goal was to assess the feasibility of redirecting an asteroid that might pose a threat to Earth. While the primary aim was to observe a minor change in Dimorphos’ path, recent research published in the Planetary Science Journal has uncovered more dramatic consequences.

Dr. Derek Richardson, a researcher involved in the mission, explained that the impact has altered Dimorphos’ shape from a previously hamburger-like form to a more elongated, football-like structure. This finding challenges earlier scientific assumptions about the formation and behavior of asteroid moons.

Prior to the DART mission, it was believed that asteroid moons would elongate over time, with their main axis always aligned towards their parent asteroid. However, the changes observed in Dimorphos suggest a different dynamic at play. Instead of elongating, the moon appears to have contracted and become more compact due to the impact.

“This result contradicts previous models and indicates that the interaction between an asteroid moon and its parent asteroid is more complex than we thought,” Richardson noted in a university press release. He also pointed out that this shape change has likely affected Dimorphos’ interaction with Didymos, adding another layer of complexity to the dynamics of such celestial bodies.

In addition to the shape alteration, Dimorphos has been reported to be ‘tumbling’ unpredictably in space. The asteroid moon’s rotation has become erratic, causing it to present different faces to Didymos rather than maintaining a consistent orientation. This tumbling effect further complicates the understanding of how impact events can influence asteroid behavior.

The insights gained from the DART mission are valuable for future planetary defense strategies. Understanding the impact on Dimorphos’ shape and its subsequent effects on orbit and rotation provides crucial data for managing potential threats from asteroids or comets. Dr. Richardson emphasized, “DART gave us insight into complicated gravitational physics that you can’t replicate in a lab, helping us calibrate our efforts to defend Earth.”

The research underscores the importance of developing and refining methods to address potential asteroid threats. With the possibility of an asteroid or comet endangering Earth, the mission’s findings offer an additional line of defense and improve preparedness for such cosmic hazards.

NASA’s DART mission has not only demonstrated the feasibility of redirecting an asteroid but has also provided unexpected revelations about the physical changes an asteroid moon can undergo following an impact. These findings enhance our understanding of asteroid dynamics and contribute to global efforts in planetary defense.