Nasa launches asteroid-deflecting spacecraft on SpaceX Falcon 9 rocket

Move will test technique that one day might avert an apocalyptic collision with Earth

Nasa launched a spacecraft Tuesday night on a mission to smash into an asteroid and test whether it would be possible to knock a speeding space rock off course if one were to threaten Earth. The DART spacecraft, short for Double Asteroid Redirection Test, lifted off from Vandenberg Space Force Base atop a SpaceX Falcon 9 rocket in a $324 million project with echoes of the Bruce Willis movie “Armageddon.”

The $324 million DART mission is unusual for NASA, a civilian agency that focuses mainly on exploration, climate monitoring and hunting for signs of past life in our solar system. While it coordinates with and relies on the US Department of Defense for some activities, NASA has not traditionally been responsible for leading efforts to protect the United States — or Earth, for that matter — from any security threat.

If all goes well, the boxy, 1,200-pound (540-kilogram) craft will slam head-on into Dimorphos, an asteroid 525 feet (160 meters) across, at 15,000 mph (24,139 kph) next September.

“This isn’t going to destroy the asteroid. It’s just going to give it a small nudge,” said mission official Nancy Chabot of Johns Hopkins Applied Physics Laboratory, which is managing the project.

Dimorphos orbits a much larger asteroid called Didymos. The pair are no danger to Earth but offer scientists a better way to measure the effectiveness of a collision than a single asteroid flying through space.

Dimorphos completes one orbit of Didymos every 11 hours, 55 minutes. DART’s goal is a crash that will slow Dimorphos down and cause it to fall closer toward the bigger asteroid, shaving 10 minutes off its orbit. The change in the orbital period will be measured by telescopes on Earth. The minimum change for the mission to be considered a success is 73 seconds. The DART technique could prove useful for altering the course of an asteroid years or decades before it bears down on Earth with the potential for catastrophe.

A small nudge “would add up to a big change in its future position, and then the asteroid and the Earth wouldn’t be on a collision course,” Chabot said. With inputs from NYT