NASA is scheduled to collide a high-speed spacecraft with an asteroid in an attempt to change its orbit using a technique called a "kinetic impactor".
The mission is called the Double Asteroid Redirection Test (DART) and launched on Nov. 23, 2021, atop a SpaceX Falcon 9 rocket. The spacecraft successfully exited Earth's atmosphere, and since then, it has been on a journey towards its target, a binary near-Earth asteroid system called Didymos and its smaller moonlet Dimorphos. The DART mission is the very first planetary defense mission that will attempt to deflect an asteroid, and the results from the mission, if the method is proven effective, will affect how Earth as a planet defends itself from asteroids entering our orbit.
The small spacecraft headed on a suicide mission with the Dimorphos will approach the space rock at extremely high speeds, with NASA officials estimating that the craft will be traveling 14,760 mph or 4.1 miles per second. The extreme speed of the aircraft and the kinetic power that will be generated by its impact should be enough to change the Dimorphos' orbit around the larger Didymos. To what degree the orbit changes will determine if the mission has been a success and if the results line up with NASA pre-launch estimations.
It should be noted that Didymos and Dimorphos aren't threats to Earth, and are just being used by NASA to test this method of planetary defense. Furthermore, about 30 near-Earth asteroids are discovered each week, and having a reliable method of deflecting space rocks that are on a collision course with Earth is for everyone's benefit.
Didymos and Dimorphos weren't randomly selected either, NASA officials chose this binary asteroid system due to Dimorphos being the approximate size of an asteroid that would cause significant damage to Earth if it did reach the surface. Additionally, researchers chose the pair of space rocks for their proximity to our planet as they are so close that ground-based telescopes are able to observe the results.
DART is expected to collide with Dimorphos in late September, according to the last announcements from NASA.
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