Topline
An unmanned spacecraft built for NASA’s Double Asteroid Redirection Test (DART) successfully slammed into the Dimorphos asteroid Monday evening, aiming to test a technique that scientists hope could stop dangerous asteroids from threatening Earth.
This illustration depicts NASA’s DART probe and the Italian Space Agency’s LICIACube before impact … [+]
Key Facts
The 1,260-pound DART spacecraft crashed into Dimorphos—which is about 525 feet wide—at a speed of roughly 14,000 miles per hour, aiming to change the asteroid’s orbit by a tiny amount that will be measured over the next few weeks, according to Johns Hopkins University, which built the spacecraft for NASA.
Monday’s crash was witnessed by LICIACube, a small Italian-made companion probe that separated from DART earlier this month, rigged with cameras to record the test.
Surprising Fact
Dimorphos never posed a risk to our planet, but Johns Hopkins says it was “the ideal candidate for humankind’s first planetary defense experiment.” It orbits around a larger Sun-orbiting atmosphere called Didymos, and its trajectory is easy to observe from Earth, allowing scientists to measure how the DART crash changes Dimorphos’ orbit.
Big Number
$330 million. That’s the DART program’s total cost, according to Reuters, a relative bargain compared to some of NASA’s multi-billion-dollar manned spaceflight contracts.
Key Background
If $330 million seems like a lot to burn on a spacecraft that’s designed to crash into a space rock, NASA and Johns Hopkins say the mission is designed to help prevent potentially catastrophic asteroids from careening toward Earth. DART tested a technique known as “kinetic impact deflection,” in which the course of an asteroid is altered through a fast collision with a human-produced object, redirecting it away from the planet. NASA is currently tracking some 1,419 near-earth asteroids that appear to pose a nonzero risk of hitting Earth, though in some cases, these asteroids are decades or even a century away from the planet. The agency says no known asteroids that are larger than 140 meters—which is large enough to cause mass casualties—poses a significant threat to the planet over the next century, though even a smaller asteroid could cause injuries and destruction.
Further Reading
NASA Will Crash A Spacecraft Into An Asteroid For Science! (Forbes)
