Why did NASA’s spacecraft crash into an asteroid?

Cape Canaveral, Fla. (AP) — NASA will destroy a small, harmless asteroid in its first world-saving experiment millions of miles away.

On Monday, a spacecraft called Dart will zero in on the asteroid, crashing into it head-on at 14,000 mph (22,500 km/h). The impact should be enough to push the asteroid into a tighter orbit around its companion space rock — suggesting that if a killer asteroid is heading our way, we’ll have a chance to divert it.

“It was a very old-fashioned plot from science fiction and Star Trek when I was a kid, and now it’s real,” NASA project scientist Tom Statler said on Thursday.

Cameras and telescopes will observe the crash, but it will take days or even weeks to determine whether it actually changed its orbit.

The $325 million planetary defense test began with Dart’s launch last fall.

asteroid target

The asteroid with the bullseye is Dimorphos, about 7 million miles (9.6 million kilometers) from Earth. It’s actually a small companion to a 2,500-foot (780-meter) asteroid called Didymos, Greek for twin. Discovered in 1996, Didymos is spinning so fast that scientists think it ditched the material that eventually formed the small moons. Dimorphos — about 525 feet (160 meters) wide — orbit their parent body less than a mile (1.2 kilometers).

“It’s really about asteroid deflection, not destruction,” said Nancy Chabot, a planetary scientist and mission team leader at the Johns Hopkins Applied Physics Laboratory, which is managing the work. “It’s not going to blow up the asteroid. It’s not going to break it up into many pieces.” Instead, the impact would dig a crater tens of yards (meters) in size and dislodge about 2 million pounds (1 million kilograms) of rock and earth thrown into space.

NASA insists that there is zero chance of an asteroid threatening Earth, now or in the future. That’s why this pair was chosen.

Dart, Impactor

The Johns Hopkins lab took a minimalist approach when developing Dart (short for Double Asteroid Redirection Test) because it was essentially a battering ram and faced certain destruction. It has only one instrument: a camera for navigation, positioning and recording the eventual action. Considered to be essentially a pile of rubble, Dimorphos will appear as blips an hour before impact, growing larger and larger in camera images sent back to Earth. Managers trust Dart to miss the bigger Didymos. The spacecraft’s navigation was designed to distinguish between the two asteroids and target the smaller one for the final 50 minutes.

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The small vending machine is 1,260 pounds (570 kilograms) in size, and the spacecraft will hit the roughly 11 billion pounds (5 billion kilograms) asteroid. “Sometimes we describe it as driving a golf cart into the Great Pyramid,” Chabot said.

Unless Dart misses out — NASA thinks there’s less than a 10% chance of that happening — it’s going to be the end of Dart’s road. If it screams through two space rocks, it will meet their Take 2 again years later.

save the earth

Little Dimorphos runs a lap around Big Didymos every 11 hours and 55 minutes. Dart’s effects should be reduced by about 10 minutes. While the impact itself should be apparent immediately, it could take weeks or more to verify the small moon’s adjusted orbit. Cameras on Dart and the mini-Tagaron satellite will capture the collision up close. Telescopes on seven continents, along with the Hubble and Webb Space Telescopes and NASA’s asteroid-hunting Lucy spacecraft, may see a bright flash as Dart hits Dimorphos and pours rock and mud into space. The observatory will track the pair of asteroids as they orbit the sun to see if Dart has altered Dimorphos’ orbit. In 2024, a European spacecraft called Hera will retrace Dart’s journey to measure the impact.

Chabot said that while the expected nudge should only change the position of the small satellite slightly, it will lead to a major shift over time. “So if you’re going to do this for planetary defense, you’re doing it 5, 10, 15, 20 years in advance to make this technology work,” she said. Even if Dart misses out, the experiment will still provide valuable insights, said NASA program executive Andrea Riley. “That’s why we’re testing. We want to do it now, not when we actually need it,” she said.

Asteroid mission rich

Earth is chasing asteroids.NASA collects nearly a pound (450 grams) of rubble from asteroid Bennu Go to Earth. The collection should arrive in September next year. Japan was the first country to retrieve a sample of an asteroid, accomplishing the feat twice. China hopes to follow suit, launching missions in 2025.NASA’s Lucy spacecraftMeanwhile, after launching last year, it will head to an asteroid near Jupiter. Another spacecraft, Near-Earth Asteroid Scout, is loaded onto NASA’s Crescent rocket awaiting liftoff; next year it will use a solar sail to fly over space rocks smaller than 60 feet (18 meters). In the next few years, NASA also plans to launch a census telescope to identify hard-to-find asteroids that could pose a risk. An asteroid mission has been grounded while an independent review committee weighs its future.NASA’s Spirit Spacecraft A metal-rich asteroid between Mars and Jupiter was supposed to launch this year, but the team couldn’t test the flight software in time.

Hollywood movie

Hollywood has produced dozens of killer space rock movies over the decades, including 1998’s “Doomsday,” Bruce Willis to Cape Canaveral to shoot, and last year’s Leonardo DiCapri “Don’t Look Up” starring Ao. Star lineup. NASA’s planetary defense officer Lindley Johnson said he’s seen them since 1979’s “Meteor,” his personal favorite “since Sean Connery played me.” He noted that while some sci-fi movies are more accurate than others, entertainment always wins. The good news is that the coast appears to be clean for the next century, with no known threats. Otherwise, “it’s like a movie, right?” said Thomas Zurbuchen, NASA’s science mission chief. Worrying, however, are the unknown threats. Less than half of the 460-foot (140-meter) long object has been confirmed, with millions of smaller but still dangerous objects roaming around. “These threats are real, and what’s special about this time is that we can do something about it,” Zubchen said. Not blowing up an asteroid like Willis’ character — that would be a last-minute move — or begging government leaders to act, in vain, like DiCaprio’s character. If time permits, the best strategy may be to push the menacing asteroid away, like a dart.


The Associated Press Health and Science Division was supported by the Howard Hughes Medical Institute Division of Science Education. The Associated Press is solely responsible for all content.

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