It worked! Humanity has moved a celestial object for the first-ever time.
As a test of a potential asteroid-deflection scheme, NASA’s DART spacecraft shortened the orbit of asteroid Dimorphos by 32 minutes — a far greater change than astronomers expected.
Double Asteroid Redirection Testing, or DART, I rammed into the small asteroidAt approximately 22,500 kilometers an hour on September 26th (SN: 9/26/22). Our goal was to bring Dimorphos closer to Didymos, the larger asteroid it orbits.
Earth is not at risk from Didymos or Dimorphos. DART’s mission was to help scientists figure out if a similar impact could nudge a potentially hazardous asteroid out of harm’s way before it hits our planet.
It was a huge success. Before the impact, Dimorphos orbited Didymos once every 11 hours and 55 seconds. After, It took 11 hours 23 minutes to orbit.NASA announced the October 11th date in a news conference.
“For the first time ever, humanity has changed the orbit of a planetary body,” said NASA planetary science division director Lori Glaze.
The asteroids were observed by four telescopes in Chile, South Africa and South Africa every night following the impact. The telescopes can’t see the asteroids separately, but they can detect periodic changes in brightness as the asteroids eclipse each other. All four telescopes observed eclipses with an 11-hour, 23 minute orbit. Nancy Chabot from Johns Hopkins Applied Physics Laboratory in Laurel (Md.) confirmed the results. They bounced radio waves off of asteroids to determine their orbits.
The minimum change for the DART team to declare success was 73 seconds — a hurdle the mission overshot by more than 30 minutes. According to the DART team, the impactor’s spectacular plume of debris gave the mission an extra boost. The impact itself gave some momentum to the asteroid, but the debris flying off in the other direction pushed it even more — like a temporary rocket engine.
“This is a very exciting and promising result for planetary defense,” Chabot said. The orbital period change was only 4 percent. “It just gave it a small nudge,” she said. It is vital to know when an asteroid is heading our way. For something similar to work on an asteroid headed for Earth, “you’d want to do it years in advance,” Chabot said. An upcoming space telescope called Near Earth Asteroid SurveyorOne of many projects that aims to provide this early warning is the one above.
