‘Spacecraft Impact Alters Asteroid Permanently’

NASA’s Double Asteroid Redirection Test (DART) proved successful in demonstrating the space agency’s capability to redirect potentially dangerous asteroids. The mission involved sending a vending machine-sized spacecraft to a binary asteroid system, where it collided with the moonlet Dimorphos, orbiting a larger asteroid named Didymos. The impact, which occurred on September 26, 2023, resulted in a 33-minute reduction in Dimorphos’ orbital time around Didymos, now completing one orbit in 11 hours and 23 minutes.

Researchers led by University of Bern scientist Sabina Raducan conducted high-level computer simulations following the impact, revealing that Dimorphos is a loose, rubble-pile asteroid. The collision caused global deformation, with interior material surfacing. Approximately 0.5% to 1% of Dimorphos’ mass was ejected, and 8% was redistributed throughout the asteroid.

Raducan noted that the findings shed light on the likely formation of Dimorphos through rotational mass shedding and re-accumulation from Didymos, contributing to the understanding of similar binary systems in the solar system. Additionally, the study suggests that small, rubble-pile asteroids like Dimorphos are efficient to deflect using the kinetic impactor technique for planetary defense. However, a reconnaissance mission would be necessary to accurately assess an asteroid’s properties before attempting deflection.