The world's first planetary defense test was conducted on Sept. 26 when NASA's Double Asteroid Rendezvous Test (DART) mission collided with a tiny asteroid 7 million miles from Earth.
The mission's objective is to sufficiently alter the orbit of the space rock Dimorphos around its larger asteroid parent Didymos to demonstrate that humans are capable of deflecting a hazardous asteroid away from Earth in the event that one were to approach.
At 7:14 p.m. EDT, the DART spacecraft collided with Dimorphos, traveling at a staggering 14,000 mph.
The DART mission is the first demonstration of a "kinetic impactor" for planetary defense, which involves crashing a spacecraft into an asteroid to alter its orbit. It's a simple way to defend the Earth if a potentially deadly asteroid is discovered five or ten years before an impending collision.
As DART approached Dimorphos, it changed from a mysterious bright dot to a complex scene of stones, crags, and gloomy terrain. Then, just on schedule, the DART live feed went black, and flight controllers inside DART's mission operations center celebrated triumphantly with hugs and high fives.
DART nailed its asteroid target.
According to NASA scientists, there is a small but realistic chance that an asteroid would strike Earth catastrophically. NASA frequently searches the sky for new asteroids and has discovered around 40% of those that potentially threaten Earth and are as wide as 500 feet. The Near Earth Object Surveyor is a brand-new space telescope sentinel that NASA is creating specifically to look for potentially dangerous asteroids in the solar system. By 2026, that mission might get underway.
From their separate vantage points throughout the solar system, NASA's new James Webb Space Telescope, the Hubble Space Telescope, and the Lucy spacecraft on its own asteroid mission all monitored the collision.
A massive network of ground-based telescopes was trained on the event and will be tracking the binary Didymos-Dimorphos system over time to observe how much quicker Dimorphos is currently traveling in its orbit.
The European Space Agency is also considering a trip to the Didymos-Dimorphos asteroid system to investigate the impact of DART. The Hera mission, which will launch a spacecraft to the asteroid in 2024 and orbit the binary asteroid system by 2027, will explore the space rocks and the DART-created crater on Dimorphos.
It will take some time to determine whether the DART impact was a success as a planetary defense test.