NASA’s DART Successfully Collides with Asteroid

Artist’s rendition of the test - NASA/John Hopkins

Over the past two decades, scientists around the world have been developing a system to protect Earth from dangerous asteroids and comets. On Sept. 26, NASA’s Double Asteroid Redirection Test (DART) proved to be a manifestation of these efforts, when the projectile successfully collided with the asteroid Dimorphos.

DART is the first mission developed by NASA’s Planetary Defense Coordination office. The success of this mission shows a coordination of global efforts to protect the Earth against hazardous asteroids. Dimorphos, a small, non-threatening asteroid, orbiting a larger asteroid Didymos, was selected to be the target in this test.

The DART was designed as a kinetic impactor to make a head-on collision with Dimorphos and transfer its kinetic energy and momentum to the asteroid. The DART is a small cube device measuring only a fraction of this asteroid’s mass, weighing in at 550 kilograms, whereas Dimorphos is five billion kilograms.

According to NASA’s website, in 2003, astronomer Petr Pravec was observing the asteroid Didymos when he noticed a pattern around the asteroid resembling a small moon. Dimorphos, previously referred to as Didymos B, was approximately 160 meters in diameter. It was identified as the perfect target for the DART, because of its orbit around Didymos and its proximity to Earth in 2022.

After ten months of flying over 6.8 million miles, the DART successfully collided with Dimorphos. Since then, a team of scientists have been observing the impact on Dimorphos’ orbit around Didymos. According to NASA’s Jet Propulsion Lab’s website, scientists have observed that the impact slowed Dimorphos’ orbit around Didymos by 32 minutes to 11 hours and 23 minutes.

Even though this may seem small, Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA’s Washington headquarters, stresses its significance, saying in a media release on NASA’s website on Sept. 26, “Now we know we can aim a spacecraft with the precision needed to impact even a small body in space. Just a small change in its speed is all we need to make a significant difference in the path in which an asteroid travels.

“DART’s success provides a significant addition to the essential toolbox we must have to protect Earth from a devastating impact by an asteroid,” said Lindley Johnson, NASA’s Planetary Defense Officer, in the media release. “This demonstrates we are no longer powerless to prevent this type of natural disaster. Coupled with enhanced capabilities to accelerate finding the remaining hazardous asteroid population by our next Planetar y Defense mission, the Near-Earth Object (NEO) Surveyor, a DART successor could provide what we need to save the day.”

NASA reports that the Planetary Defense Coordination Office will continue to adapt and develop the DART to improve our capabilities to detect and protect Earth against potentially threatening asteroids.