On Sept. 26, 2022, at 7:14 p.m. EDT NASA’s DART successfully collided with the asteroid moonlet Dimorphos. 

The Double Asteroid Redirection Test (DART) is part of NASA’s planetary defense strategy. The DART was NASA’s first mission dedicated to demonstrating and investigating a method of asteroid deflection. It works by deflecting an asteroid by crashing into it and causing it to redirect its route.

 NASA conducted the mission hoping it would demonstrate an effective way to deal with an asteroid in case one was ever heading towards Earth.

The DART was launched on Nov. 23, 2021, aboard a SpaceX Falcon 9 rocket. The rocket departed from an air force base in Vandenberg, Calif.

It would take the DART 10 months to reach its target. The target was Dimorphos: an asteroid moonlet seven million miles away from Earth. Dimorphos is an asteroid moonlet meaning it orbits an asteroid. 

The asteroid Dimorphos orbits is named Didymos. Together they form what is called a binary asteroid system, this means the small moon, Dimorphos, orbits a larger body, Didymos. Dimorphos is about 530 feet wide, 160 meters, in diameter. 

Didymos is about 2,560 feet, 790 meters, in diameter. On Sept. 26, 307 days after its launch, the DART successfully impacted with Dimorphos. The mission confirmed NASA has the ability to navigate a spacecraft with the intention to collide with an asteroid in order to deflect it. 

NASA will now observe Dimorphos’s path using a ground-based telescope. They will watch Dimorphos in order to confirm the DART’s impact altered the asteroid moonlet’s orbit. 

NASA expects DART’s impact to shorten Dimorphos’s orbit by 1 percent, which is roughly 10 minutes. Precisely measuring how much Dimorphos’ orbit was deflected is a big part of the mission.  

Some speculated that the DART mission would inadvertently knock Dimorphos on route to crash with Earth. NASA has cleared any rumors and assured the public that neither Dimorphos or Didymos pose any threat to Earth.