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NASA’s DART Mission Crashes Into an Asteroid to Defend the Earth
| Great! Experiments of this kind may increase our probabilities of survival against a real threat. It also gives us more info about other options that could also work against those threatening scenarios
| NASA engineer after crashing their spacecraft >I-i totes meant to do that! F-for real!
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| https://www.nytimes.com/live/2022/09/26/science/nasa-dart-asteroid-mission?smtyp=cur&smid=tw-nytimes
DART makes contact with the asteroid Dimorphos.
LAUREL, Md. — NASA destroyed a spacecraft on Monday evening.
But the engineers guiding the robotic probe were not disappointed — they cheered. Their mission was a resounding success.
On time and on target, NASA’s Double Asteroid Redirection Test spacecraft, or DART, slammed into a small asteroid at more than 14,000 miles per hour. While the asteroid poses no threat to Earth, the mission was a test of technology that could protect the planet from an oncoming space rock in the future.
Hitting an asteroid with a high-speed projectile could nudge it enough so that a direct hit becomes a near miss.
With movies like “Armageddon,” “Deep Impact” and, more recently, “Don’t Look Up,” Hollywood has long been fascinated with the prospect of disaster raining down from the cosmos. In recent years, scientists and policymakers have also taken the threat more seriously than they once did.
For many years, policymakers lacked urgency to finance efforts to protect the planet from asteroids. But that began to shift in part because astronomers have been able to find all of the big asteroids that would wreak planet-wide destruction, like the one that doomed the dinosaurs 66 million years ago, said Thomas Statler, the program scientist on the DART mission.
Impacts of a global scale occur very rarely, once every 10 million years or so. But now that that possibility has been ruled out, planners at NASA and elsewhere are thinking about the numerous smaller objects in space. Those are far more numerous, and, although they would not set off mass extinctions, they can unleash more energy than a nuclear bomb.
“The conversation has matured in a really appropriate way,” Dr. Statler said.
The growing focus on planetary defense can be in seen in a number of initiatives that NASA and Congressional appropriators have sponsored. One is the Vera Rubin Observatory, a new telescope in Chile that is financed by the United States and will systematically scan the night sky and find thousands of potentially hazardous asteroids. Another is the NEO Surveyor, a space-based telescope that NASA is working to build. It too will find many hazardous asteroids, including some that are hard to spot from Earth.
If any of those asteroids turn out to be on a collision course with Earth, the DART mission shows that deflecting them is a realistic possibility.
For the engineers on the mission, operated by the Johns Hopkins University Applied Physics Laboratory, the impact, at 7:14 p.m. Eastern time, marked the end of their work. The spacecraft, operating autonomously for the last four hours of its existence, successfully locked on its target, a 560-foot-wide asteroid named Dimorphos.
That is even more impressive because DART’s camera spotted Dimorphos for the first time a little more than an hour before it hit. Dimorphos orbits a larger asteroid, Didymos, and until then, the smaller asteroid was lost in the glare of the larger object. DART’s navigation system then shifted its gaze toward the smaller asteroid.
Up until five minutes before impact, mission controllers could have intervened if something had gone wrong. After that, they too were just spectators like everyone watching the stream of photographs of Dimorphos getting bigger and bigger.
A picture of the asteroid’s surface strewn with boulders filled the screen. Then there was one more partial image, but DART hit Dimorphos before it was all sent back.
For asteroid scientists, their work is just beginning.
About 40 telescopes on Earth were pointed at Didymos and Dimorphos, according to NASA and the mission’s managers. So were the Hubble and James Webb space telescopes as was the camera on Lucy, another NASA spacecraft. The LICIACube, a spacecraft about the size of a shoe box built by the Italian Space Agency, trailed DART to take photographs of the impact and the plume of debris. Its trajectory was shifted to the side so that it did not also crash into the asteroid.
“There’s the rest of us that are really eagerly anticipating the impacts so that we can take our science and run with it,” said Cristina Thomas, a professor of astronomy and planetary science at Northern Arizona University and lead of the observations working group for the mission. “It’s going to be so great and such an exciting once-in-a-lifetime event that we are throwing everything that we have at it.”
Over the coming days and weeks, Dr. Thomas and other astronomers will be sifting through the data and the images to figure out what DART did to Dimorphos. The key measurement will be how much Dimorphos, which had been orbiting Didymos every 11 hours, 55 minutes, has sped up. That will reflect how much momentum the spacecraft imparted to the asteroid, causing it to move closer to Didymos. The change is expected to be about 1 percent, or about seven minutes.