CAPE CANAVERAL, Fla. (AP) — In the first save-the-world experiment of its kind, NASA is about to smash a small, harmless asteroid millions of kilometers away.
A spacecraft called Dart will focus on the asteroid Monday for a head-on impact at 14,000 mph. The impact should be just enough to put the asteroid in a slightly tighter orbit around its companion space rock – demonstrating that if a killer asteroid ever comes our way, we have a good chance of deflecting it.
“This is stuff from sci-fi books and really cheesy episodes of Star Trek from my childhood, and now it’s real,” NASA Program Scientist Tom Statler said Thursday.
Cameras and telescopes will track the crash, but it will take days or even weeks to figure out if it actually changed orbit.
The $325 million planetary defense test started with Dart launched last fall.
The asteroid with the porthole on it is Dimorphos, about 7 million miles (9.6 million kilometers) from Earth. It’s actually the puny sidekick of a 2,500-foot (780-meter) asteroid named Didymos, Greek for twin. Discovered in 1996, Didymos is spinning so fast that scientists believe it ejected material that eventually formed a moon. Dimorphos – about 525 feet (160 meters) across – orbits its mother body at a distance of less than a mile (1.2 kilometers).
“This is really about asteroid deflection, not perturbation,” said Nancy Chabot, planetary scientist and leader of the mission team at Johns Hopkins University’s Applied Physics Laboratory, which is leading the effort. “That won’t blow up the asteroid. Rather, the impact will dig out a crater several tens of meters wide and hurl about 2 million pounds (1 million kilograms) of rock and dirt into space.
NASA insists there is no chance of an asteroid threatening Earth — now or in the future. That’s why the couple was chosen.
DART, THE IMPACTOR
The Johns Hopkins lab took a minimalist approach to developing Dart – short for Double Asteroid Redirection Test – as it is essentially a battering ram subject to certain destruction. It has a single instrument: a camera used for navigating, aiming, and recording your last action. Thought to be essentially a debris pile, Dimorphos will emerge as a point of light an hour before impact, appearing larger and larger in the camera images that are bounced back to Earth. Managers are confident that darts will not accidentally crash into the larger didymos. The spacecraft’s navigation is designed to distinguish between the two asteroids and target the smaller one in the last 50 minutes.
The spacecraft is the size of a small vending machine at 1,260 pounds (570 kilograms) and will smash into about 11 billion pounds (5 billion kilograms) of asteroids. “Sometimes we describe it as going into a large pyramid in a golf cart,” Chabot said.
If darts don’t miss — NASA estimates there’s less than a 10% chance it will — it’s the end of the road for darts. As it screams past both space rocks, it will encounter them again for Take 2 in a few years.
The little Dimorphos makes a circle around the big Didymos every 11 hours and 55 minutes. Dart bounce should reduce by about 10 minutes. Although the impact itself should be visible immediately, it could take a few weeks or more to verify the Moon’s changed orbit. Cameras on Dart and a mini-Tagalong satellite will capture the collision at close range. Telescopes on all seven continents, along with the Hubble and Webb Space Telescopes and NASA’s asteroid-hunter Lucy spacecraft, could see a bright flash as Dart strikes Dimorphos, catapulting streams of rock and soil into space. The observatories will track the asteroid pair as they orbit the Sun to see if Dart has changed Dimorphos’ orbit. In 2024, a European spacecraft called Hera will replicate Dart’s journey to measure the effects of impact.
Although the intended push should only slightly change the position of the small moon, Chabot says this will add up to a large shift over time. “So if you were doing this for the defense of the planet, you would be doing it five, 10, 15, 20 years in advance for this technique to work,” she said. Even if Dart misses, the experiment will still yield valuable insights, said NASA program director Andrea Riley. “That’s why we test. We want to do it now and not when it’s really necessary,” she said.
ASTEROID MISSIONS IN SHELL
Planet Earth is chasing asteroids. NASA has almost a pound (450 grams) of it Debris collected from the asteroid Bennu driven to earth. The stock should arrive next September. Japan became the first country to take asteroid samples, accomplishing the feat twice.
China hopes to follow suit with a mission in 2025. NASA’s Lucy spacecraft, meanwhile, is on its way to asteroids near Jupiter after being launched last year. Another spacecraft, Near-Earth Asteroid Scout, is loaded onto NASA’s New Moon rocket and awaits launch; It will use a solar sail next year to fly past a space rock less than 18 meters tall.
In the next few years, NASA also plans to launch a census telescope to identify hard-to-find asteroids that could pose risks. An asteroid mission is shelved while an independent review board weighs its future. NASA’s Psyche spacecraft Actually, this year should have started to a metal-rich asteroid between Mars and Jupiter, but the team could not test the flight software in time.
Hollywood has produced dozens of killer space rock movies over the decades, including 1998’s “Armageddon,” which brought Bruce Willis to Cape Canaveral to film, and last year’s “Don’t Look Up,” which starred Leonardo DiCaprio a celebrity cast.
NASA planetary defense officer Lindley Johnson estimates he’s seen them all since 1979’s Meteor, his personal favorite “since Sean Connery played me.”
While some of the sci-fi movies are more accurate than others, he noted, entertainment always wins. The good news is that the coast appears to be free for the next century, with no known threats. Otherwise “it would be like a movie, right?” said NASA’s science mission director Thomas Zurbuchen.
However, what is worrying are the unknown threats. Less than half of the 460-foot (140-meter) objects have been confirmed, with millions of smaller but still dangerous objects zooming around. “These threats are real, and what makes this time special is that we can do something about it,” Zurbuchen said.
Not by blowing up an asteroid, as Willis’ character did – that would be a last-minute last resort – or by imploring government leaders to take action, as DiCaprio’s character did in vain. If time permits, the best tactic might be to nudge the menacing asteroid out of our way like Dart.
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