University of Hawaii astronomers observed with keen interest as a small, unmanned NASA spacecraft purposely crashed into an asteroid in an unprecedented dress rehearsal for the day a killer space rock menaces Earth.
“It was quite the crescendo, with the spacecraft crashing into an asteroid like that,” said Doug Simons, director of the UH Institute for Astronomy.
The galactic slam occurred at about 1:15 p.m. Hawaii time at a harmless asteroid 7 million miles away, with the spacecraft named Dart — an acronym for Double Asteroid Redirection Test — plowing into the space rock at 14,000 mph. Scientists expected the impact to carve out a crater, hurl streams of rocks and dirt into space and, most importantly, alter the asteroid’s orbit.
“I’m surprised how excited I am,” said J.D. Armstrong, HI STAR program director and outreach coordinator for IfA on Maui. “I was talking earlier with someone, and I was asked, ‘Are you nervous about whether or not they’re going to hit it?’ And I responded, ‘I’m always going to be a little bit nervous, but I expect that they’re going to hit it. Because NASA’s very good at this.’”
Simons called the accuracy of Dart’s impact “very impressive.”
“I think they said they were 13 meters off from their nominal target,” he said. “Thirteen meters is a pretty small box at a range of 7 million miles. Talk about threading the needle.”
The $325 million mission was the first attempt to shift the position of an asteroid or any other natural object in space. That object is Dimorphos, an asteroid about the size of a football stadium. It’s a moonlet of Didymos, Greek for twin, a fast-spinning asteroid five times larger than Dimorphos.
The pair have been orbiting the sun for eons without threatening Earth, making them ideal save-the-world test candidates.
“We’re embarking on a new era of humankind, an era in which we, potentially, have the capability to protect ourselves from something like a dangerous, hazardous asteroid impact,” said Lori Glaze, NASA’s planetary science division director. “What an amazing thing. We’ve never had that capability before.
“Now is when the science starts. Now we’re going to see for real how effective we were.”
Simons said there’s a yet unseen “really cool” close-up video of the actual space collision.
“There’s this CubeSat that was deployed about 10 days or so ago from the primary spacecraft, Dart. And it flew in formation with Dart about three minutes behind. And it should have recorded … the entire event. And they’re going to download it in a day or so,” he explained.
Scientists insisted Dart would not shatter Dimorphos. The spacecraft packed a scant 1,260 pounds, compared with the asteroid’s 11 billion pounds. But that should be enough to shrink its 11-hour, 55-minute orbit around Didymos by about 10 minutes. The anticipated orbital shift of 1% might not sound like much, scientists noted. But they stressed it would amount to a significant change over years.
“Think of it this way. You’ve got something the size of a stadium floating around in space. And you’ve got something the size of a small bus hitting into it. It’s not going to be moved very much, but it’s going to be moved a little bit. It’ll gain a little bit of speed. And that small change in speed is what we’re looking for,” Armstrong said.
Armstrong and fellow IfA astronomer Dave Tholen at UH-Manoa will work with students the next couple of months to track Dimorphos’ orbit using photometric observations.
Armstrong and his HI STAR program high school students — Wilson Chau, Holden Suzuki and James Ancheta — will study data from observations from the Las Cumbres Observatory, which is a global network of telescopes that includes the 2-meter Faulkes North telescope on Maui’s Haleakala.
Tholen will mentor Vernon Roark, a UH astrophysics major who will obtain orbital shift observations as part of his senior research project. Tholen and Roark are expected to perform observations using UH’s 88-inch telescope on Maunakea, Armstrong said.
According to Armstrong, the extent of UH’s involvement in the mission’s data gathering and analysis is “to be determined.”
“If we get some really good data, I’m sure the science community would be very interested in it,” he said. “And we do have some time on the telescopes that would help us do that.”
“This mission really punctuates one of the major thrusts of the IfA, and that is planetary defense,” Simons said. “We operate two Pan-STARRS telescopes and two ATLAS telescopes between Haleakala and Mauna Loa — and, of course, the telescopes on Maunakea. And the UH Institute for Astronomy is No. 1 in the world for finding what we call NEOs, near-Earth objects, although there’s no risk of this object hitting the Earth. It really accentuates the work that we’re doing at UH.
“And In a couple of years, the Europeans are going to launch a mission called Hera, which will do another fly-by and do a reconnaissance on the impact site to further evaluate the impact from Dart. So, this is not the end of the story. There’s actually a lot more research that’s going to be conducted.”
The Associated Press contributed to this story.
Email John Burnett at jburnett@hawaiitribune-herald.com.
