NASA’s Double Asteroid Redirection Test, also known as DART, slammed into an asteroid Monday night in its first planetary defense test that could protect Earth from future threats.
“And we have impact! Fantastic! Oh! Fantastic,” were the first words from inside Johns Hopkins University Applied Physics Laboratory right after the DART vehicle collided with its target, Dimorphos, at 7:15 p.m. EDT, generating cheers from NASA engineers who worked for years on the mission.
“We are showing that planetary defense is a global endeavor, and it is very possible to save our planet,” NASA Administrator Bill Nelson told those assembled right after the successful defense test.
“We have worked on this mission for at least seven years now, and it’s been the work of over a thousand people who have put their hearts and souls into it,” Dr. Elena Adams, with the Johns Hopkins University Applied Physics Laboratory, told reporters in a news conference after impact.
“To see it so beautifully concluded today was just an incredible feeling.”
NASA scientists told reporters they were about 17 meters off-center from their exact target because the asteroid was not completely lit from all sides, but otherwise everything went exactly according to plan.
“About 40 minutes out, you were really getting the good feeling and you could tell everyone in that whole room was getting the same feeling,” said Ed Reynolds, project manager at the Johns Hopkins University APL. “It was actually a fairly relaxed environment. It wasn’t tense.”
NASA scientists said they were “precision locked” on their target about 20 minutes before impact — a milestone that drew big applause inside the laboratory about 6:50 p.m. EDT.
“We’re locked on Dimorphos. We’re maneuvering toward it and everything is looking really good,” Adams told reporters. “We’ve executed two burns and everything is on track.”
At one hour to impact, scientists got their first sighting of Dimorphos, saying it was a “clear image” and that they were on “a stable track.”
“We are starting to see Dimorphos for the first time,” Adams said. “We are getting ready to transition. We are ready to go.”
The DART vehicle crashed into Dimorphos at 7:14 p.m. EDT, at a speed of about 15,000 mph, with the goal of altering the small asteroid’s current path.
Right before impact, LICIACube was released, which recorded the spacecraft’s final moments before it crashed. It beamed the images and data back to Earth. NASA scientists said those images should be available within the next couple of days.
Whether DART’s goal of moving Dimorphos off course was achieved will not be known for a couple of months.
“So, of course, the ground base observatories are already taking data right now … but what we’re probably going to see in the next couple of months, we’re actually going to get confirmation of the exact period change that we made,” Adams said.
“So it’s not going to be tomorrow. I’m sorry. But we might see some LICIACube set images coming up in the next day or two.”
The DART mission, scientists say, will provide valuable data for NASA and the Johns Hopkins University Applied Physics Laboratory, which managed the mission. Neither Didymos nor Dimorphos posed a threat to Earth, but the same maneuver could be used to divert other asteroids from threatening the planet.
“This is an exciting time, not only for the agency but in space history and in the history of humankind, quite frankly,” said Lindley Johnson, NASA’s planetary defense officer. “This demonstration is extremely important to our future here on Earth.”
Once the spacecraft hit its target, the moonlet’s orbit around the asteroid was expected to change, which will be measured by ground-based telescopes, according to Andy Cheng, DART’s investigation team lead.
A nudge to an asteroid’s trajectory may only cause a change of millimeters a second, which isn’t very fast, but could over a long enough period of time force a threat to Earth to miss the planet completely.
Dimorphos was estimated to be about 560 feet in diameter, about the size of the Washington monument.
“Dimorphos is a tiny asteroid,” Tom Statler, the mission’s program scientist at NASA, said during an earlier news conference.
“We’ve never seen it up close. We don’t know what it looks like. We don’t know what the shape is. And that’s just one of the things that leads to the technical challenges of DART,” Statler said earlier Monday. “Hitting an asteroid is a tough thing to do.”
DART was launched Nov. 23, for its $330 million mission, on top of a SpaceX Falcon 9 rocket from California’s Vandenberg Space Force Base.
The vending machine-sized vehicle detached from the stage-two rocket about an hour into its journey, absorbing the sun’s energy to power its 7-million-mile trip to its impact target, the Didymos asteroid system.
Dr. Thomas Zurbuchen, NASA science associate administrator, said DART is the first of many planetary defense missions planned.
Dr. Kelly Fast, a program scientist in NASA’s planetary Science Division, said there are more than 27,500 known near-Earth asteroids, none of which pose a threat to the planet, but there are many others out there that have yet to be detected.
“The subset that are a large size that really could do damage that the Earth’s atmosphere doesn’t protect us from, that larger population, we’ve probably only found about 40% of those,” she said. “So we keep searching.”