NASA leaders say Earthlings now have a way to fight back if an asteroid is headed here after successfully changing the orbit of an asteroid by slamming an appliance-size spacecraft into the space rock.
NASA’s Double Asteroid Redirect Test (DART) spacecraft launched from California last fall and zoomed through space to reach a binary asteroid system — the larger Didymos and its smaller moonlet Dimorphos, about 7 million miles from Earth.
Two weeks after the impact, teams with the Johns Hopkins University Applied Physics Laboratory (JHUAPL) and NASA provided an update on what they’ve learned from DART’s smash.
On Sept. 26, DART used autonomous navigation to hone in on Dimorphos, then charge head first at about 15,000 mph, acting as a battering ram into the space rock. The goal was to test one potential plan to protect Earth from asteroids known as the kinetic impactor theory. If the mission was a success, DART would change Dimorphos’ orbit around Didymos but only by a few seconds.
NASA Administrator Bill Nelson called the first planetary defense test a “bullseye,” confirming DART’s impact changed the orbit of Dimorphos around Didymos by 32 minutes.
The moonlet asteroid previously took almost 12 hours to orbit the larger Didymos. Now, based on ground-based telescope observations Dimorphos orbits the asteroid in 11 hours and 23 minutes, a change of about 4%.
“All of us have a responsibility to protect our home planet. After all, it’s the only one we have,” Nelson said. “And this mission shows that NASA is trying to be ready for whatever the universe throws at us. I believe that NASA has proven that we are serious as a defender of the planet.”
DART coordination lead Nancy Chabot, with APL, said this technique could possibly be used to potentially deflect an asteroid in the future but with more lead time.
“If you wanted to do this in the future, potentially it could potentially work, but you’d want to do it years in advance,” Chabot said. “Warning time is really key here in order to enable this sort of asteroid deflection to potentially be used in the future as part of a much larger planetary defense strategy.”
NASA used several methods to determine DART’s success.
The spacecraft brought along a companion in the form of a tiny spacecraft built by the Italian Space Agency (Agenzia Spaziale Italiana) called LICIACube.
Three minutes after DART made a direct hit, LICIACube flew by the asteroid to survey the damage. The Italian spacecraft recorded the impact area, debris, and DART’s final moments using two cameras, LUKE and LEIA.
Around the world scientists using ground-based telescopes have been monitoring the binary asteroid system’s orbit. Already, researchers at ground telescopes are reporting their findings.
Two days after DART’s impact, astronomers used a National Science Foundation facility telescope in Chile to observe the massive dust and debris trail coming from Dimorphous. The debris from the moonlet asteroid has created a comet-like tail on Dimorphos that is more than 6,000 miles long.
Multiple spacecraft were also watching the crash when it happens, including the James Webb Space Telescope, Hubble Space Telescope, and NASA’s Lucy spacecraft.
On Tuesday, NASA Planetary Science Director Lori Glaze shared a new image taken this weekend of the new tail on Dimorphous.
Over the next few months, mission scientists will continue to observe the orbital change made by DART’s hit.
Finally, the last check will be in the form of HERA, a European Space Agency spacecraft launching in 2024. HERA will visit Didymos and Dimorphos and see the impact area up close.