NASA Successfully Crashes Spacecraft Into Asteroid To Practice Protecting Earth

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.

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 NASA and Johns Hopkins University, which built the spacecraft for the U.S. space agency.

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 any 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 asteroid 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 and telescope programs.

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 have a nonzero chance 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.

Tangent

Johns Hopkins says kinetic impact deflection is the most well-developed known method for diverting asteroids from Earth, but scientists have offered up a few other strategies that could save us from going the way of the dinosaurs. In particular, a spacecraft could fly alongside an asteroid and use its gravity to gently nudge the rock onto a different trajectory. Using a nuclear weapon to destroy an asteroid may have worked for Bruce Willis, but some experts fear explosives could break an asteroid into fragments that are still large enough to hit Earth, and NASA says asteroids move far too quickly to destroy minutes or hours before crashing into the planet.

Further Reading

NASA Will Crash A Spacecraft Into An Asteroid For Science! (Forbes)