NASA's DART Spacecraft Worked! Asteroid Killer Changed the Harmless Space Rock's Orbit More Than Expected

NASA's Double Asteroid Redirection Test (DART) impact with the asteroid Dimorphos demonstrates a possible technique to protect Earth from asteroids that might come its way and cause massive devastation.

The space agency's administrator Bill Nelson said that DART represents an unprecedented success for planetary defense and a mission of unity with a real benefit for all humanity. He added that this international collaboration has turned science fiction into a science fact that demonstrates one way to protect the planet.

First-Ever Planetary Defense Test

The DART spacecraft slammed into Dimorphos just after 7:14 ET on September 26 with the sole instrument called the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), per NASA.

The instrument works in tandem with the guidance, navigation, and control system, as well as the Small-body Maneuvering Autonomous Real-Time Navigation (SMART Nav) algorithms that enabled the spacecraft to identify the target asteroid. These systems guided the DART spacecraft to crash into the asteroid at roughly 14,000 miles (22,350 kilometers) per hour to slow its orbital speed.

DART's CubeSat companion Light Italian CubeSat for Imaging of Asteroids (LICIACube) by the Italian Space Agency captured the impact that resulted in a cloud of ejected matter. The images of DRACO and LICIACube together are intended to provide a view of the effects of the collision that inform researchers of the effectiveness of kinetic impact in deflecting an asteroid.

NASA's Planetary Defense Officer Lindley Johnson said that the success of the mission is a significant addition to the essential toolbox that will protect Earth from devastating impact by an asteroid. More so, this demonstrates that the planet is no longer powerless to prevent this type of natural disaster.

Over the coming weeks, photos from LICIACube will be downlinked to Earth one by one and will help characterize the ejecta produced and precisely measure the orbital change of Dimorphos and see how effectively DART deflected the asteroid. The results will validate and help improve scientific computer models critical to predicting the effectiveness of this technique.

How Successful Was DART's Collision with Dimorphos?

According to National Geographic, DART did not just nudge Dimorphos onto a slightly tighter orbital path. Rather, it delivered a cosmic face-punch that reduced 32 minutes of the moonlet's orbit and turned it into something that resembles a comet with a dusty debris tail some 6,000 miles long.

Keck Observatory chief scientist John O'Meara said that the impact was unexpected, blasting too much of the asteroid. But perhaps that is what happens when a rubble pile is impacted, he added. The mission was originally to tighten Dimorphos' orbit to over a minute, but the result far exceeded their expectation.

For DART's mission to be considered a success, the impact should have shortened the 11-hour, 55-minute orbit of Dimorphos by at least 73 seconds. They estimated that the collision would result in a larger difference of about 10 minutes, but it resulted in over 30 minutes that had not come up as a favored possibility before the impact.

Scientists are now busy studying the plume created by the impact and are trying to know how much material was ejected, how large the debris is, and what are they made of. They also plan to make even more detailed observations of the asteroid's new orbit to work out how circular it is and whether it wobbles.

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