Why is a NASA spacecraft crashing into an asteroid?

CAPE CANAVERAL, Florida. (AP) – In the first experiment of its kind to save the world, NASA is about to hit a small and harmless asteroid millions of miles away.

A spacecraft called the Dart will focus on the asteroid on Monday, intent on slamming it head-on at 14,000 mph (22,500 km / h). The impact should be just enough to push the asteroid into a slightly tighter orbit around its companion space rock, demonstrating that if a killer asteroid headed towards us, we would have the ability to deflect it.

“This is stuff from science fiction books and really mundane episodes of” StarTrek “from when I was a kid, and now it’s real,” NASA program scientist Tom Statler said Thursday.

Cameras and telescopes will watch the incident, but it will take days or even weeks to find out if it has actually changed orbit.

The $ 325 million planetary defense test began with the launch of Dart last fall.


The asteroid with the bull’s-eye on it is Dimorphos, about 7 million miles (9.6 million kilometers) from Earth. It is actually the weak companion of a 780-meter asteroid called Didymos, which means twin in Greek. Discovered in 1996, Didymos spins so fast that scientists believe it threw material away that eventually formed a moon. Dimorphos – about 525 feet (160 meters) in diameter – orbits its parent body at a distance of less than a mile (1.2 kilometers).

“It’s really about asteroid deflection, not disruption,” said Nancy Chabot, a planetary scientist and mission team leader at Johns Hopkins University’s Applied Physics Laboratory, who is managing the effort. “This won’t blow up the asteroid. It won’t do it in many pieces. ”Rather, the impact will excavate a crater the size of tens of yards (meters) and send about 2 million pounds (1 million kilograms) of rock and earth into space.

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


The Johns Hopkins Lab took a minimalist approach in developing Dart – short for Double Asteroid Redirection Test – as it is essentially a ram and risks certain destruction. It has a single tool: a camera used to navigate, point and report on the final action. Essentially believed to be a pile of rubble, Dimorphos will emerge as a point of light an hour before impact, looming larger and larger in the camera images sent to Earth. Managers are confident that Dart won’t crash into the bigger Didymos by mistake. The spacecraft’s navigation is designed to distinguish between the two asteroids and, in the last 50 minutes, aim for the smaller one.

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The size of a small vending machine at 1,260 pounds (570 kilograms), the spacecraft will crash into about 11 billion pounds (5 billion kilograms) of asteroid. “Sometimes we describe it as racing a golf cart against a Great Pyramid,” said Chabot.

Unless Dart is missing – NASA estimates the odds of that happening at less than 10% – it will be the end of the road for Dart. If he passes both space rocks screaming, he will encounter them again in a couple of years for Take 2.


Little Dimorphos completes a loop around big Didymos every 11 hours and 55 minutes. The impact of Dart should reduce by approximately 10 minutes. Although the hit itself should be immediately noticeable, it may take a few weeks or more to verify the moon’s changed orbit. Cameras on Dart and a Tagalong mini satellite will capture the collision up close. Telescopes on all seven continents, along with NASA’s Hubble and Webb space telescopes and NASA’s asteroid-hunting spacecraft Lucy, could see a bright flash as Dart hits Dimorphos and sends streams of rock and earth cascading into space. Observers will track the pair of asteroids as they circle the sun, to see if Dart has altered Dimorphos’ orbit. In 2024, a European spacecraft named Hera will retrace Dart’s journey to measure the results of the impact.

Although the predicted thrust should only slightly change the position of the moon, Chabot says this will result in a major shift over time. “So if you were to do it for planetary defense, you’d be doing it five, 10, 15, 20 years in advance for this technique to work,” he said. Even if Dart is missing, the experiment will still provide valuable information, said Andrea Riley, a NASA program executive. “That’s why we test. We want to do it now rather than when there is a real need, ”he said.


Planet Earth is on the run to chase asteroids. NASA has nearly one pound (450 grams) of rubble collected from the asteroid Bennu direct to Earth. The stock should arrive next September. Japan was the first to recover asteroid samples, accomplishing the feat twice. China hopes to follow suit with a mission to launch in 2025. NASA’s Lucy spacecraft, meanwhile, is headed for asteroids near Jupiter after launching last year. Another spacecraft, Near-Earth Asteroid Scout, is loaded into NASA’s lunar rocket awaiting take-off; will use a solar sail to fly over a space rock that is less than 60 feet (18 meters) next year. 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 grounded while an independent review committee evaluates its future. NASA’s Psyche spacecraft It was supposed to be launched this year on a metal-rich asteroid between Mars and Jupiter, but the team couldn’t test the flight software in time.


Hollywood has churned out dozens of killer-space-rock films over the decades, including 1998’s “Armageddon” which took Bruce Willis to Cape Canaveral for filming, and last year’s “Don’t Look Up” starring Leonardo DiCaprio. leading a … stellar cast. NASA planetary defense officer Lindley Johnson thinks he’s seen them all since 1979’s “Meteor”, his personal favorite “since Sean Connery played me.” While some of the science fiction films are more accurate than others, he noted, entertainment always wins. The good news is that the coast looks clear for the next century, with no known threats. Otherwise, “it would be like movies, right?” said NASA science mission chief Thomas Zurbuchen. What is worrying, however, 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 it special this time is that we can do something about it,” said Zurbuchen. Not blowing up an asteroid like Willis’ character did – it would be a last-minute last resort – or begging government leaders to act like DiCaprio’s character did in vain. If time permits, the best tactic may be to drive away the menacing asteroid, such as Dart.


The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.


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