Ten months after NASA’s DART spacecraft was aimed at a mini-asteroid, the probe hit the bull’s eye today in a practice round for planetary defense that got an assist from engineers at Aerojet Rocketdyne in Redmond, Wash.
DART — an acronym that stands for “Double Asteroid Redirection Test” — was designed to find out how much impact a projectile could have for diverting a potentially threatening asteroid away from Earth.
In this case, the object posed no actual threat. DART’s target was Dimorphos, an asteroid the size of Egypt’s Great Pyramid that’s in orbit around a half-mile-wide asteroid called Didymos. Both celestial bodies are on a path that ranges out beyond Mars’ orbit and comes close enough to Earth’s orbit for study. At the time of today’s impact, the double-asteroid system was nearly 7 million miles from our planet.
The mission team clapped and cheered at Johns Hopkins University’s Applied Physics Laboratory in Maryland as near-real-time imagery from the spacecraft’s DRACO camera showed Dimorphos looming larger in the metaphorical windshield. The DART spacecraft body, which NASA says weighed about 1,260 pounds and was roughly the size of a vending machine, struck the mini-moon at an estimated velocity of 14,000 mph.
“Oh, fantastic!” Lori Glaze, the director of the Planetary Science Division at NASA’s Science Mission Directorate, said as the camera went dead. “Now is when the science starts.”
After the impact, APL director Ralph Semmel joked about the spacecraft’s destruction. “Never before have I been so excited to see a signal go away,” he said.
