Cape Canaveral, Fla. (AP) — In a save-the-world experiment, first of its kind, NASA is about to capture a tiny, harmless asteroid millions of miles away.
A spacecraft named Dart will zero in on the asteroid Monday, intending to slam it head-on at 14,000 mph (22,500 kph). The impact should be enough to nudge the asteroid into a slightly tighter orbit around its companion space rock – indicating that if a killer asteroid ever comes our way, we’ll stand a fighting chance of turning it around.
“From when I was a kid, it’s been the stuff of science-fiction books and really funny episodes of “Startrack,” and now it’s real,” NASA program scientist Tom Statler said Thursday.
Cameras and binoculars will watch the crash, but it will take days or even weeks to find out if it actually changed orbit.
The $325 million planetary defense test began with the launch of Dart last fall.
Upon it is the bull’s-eye asteroid Dimorphos, which lies 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 threw off material that eventually formed a moonshine. Dimorphos – about 525 feet (160 m) across – 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, which is managing the effort. “It’s not going to blow up the asteroid. It’s not going to smash it into a lot of pieces.” Instead, the impact would dig a crater tens of yards (meters) in size and hurl some 2 million pounds (1 million kilograms) of rocks and dirt into space.
NASA insists that there is a zero chance that either an asteroid will threaten Earth – now or in the future. So this pair was chosen.
The Johns Hopkins Lab took a minimalist approach in developing the Dart – short for Double Asteroid Redirect Testing – noting that it is essentially a battering ram and certainly faces destruction. It has only one tool: the camera used to navigate, aim, and chronicle the final action. Considered essentially as a rubble pile, Dimorphos would emerge as a point of light an hour before the impact, getting bigger and bigger in camera images and back to Earth. The managers are confident that the dart will not accidentally break into large didymos. The spacecraft’s navigation is designed to differentiate between the two asteroids and, in the last 50 minutes, target the smaller one.
At 1,260 pounds (570 kilograms) the size of a small vending machine, the spacecraft will bump into an approximately 11 billion pounds (5 billion kilograms) asteroid. “Sometimes we describe it as driving a golf cart across a great pyramid,” Chabot said.
As long as Dart doesn’t miss—NASA has a chance of less than 10%—it will be the end of the road for Dart. If it screams behind both space rocks, it will face them again for Take 2 in two years.
Little Dimorphos completes one revolution around the larger Didymos every 11 hours and 55 minutes. The effect of the dart should go away in about 10 minutes. Although the strike should be immediately apparent, it may take a few weeks or more to verify the moon’s rotated orbit. Dart-mounted cameras and a mini TagLong satellite will capture the collision up close. Telescopes on all seven continents, along with the Hubble and Webb Space Telescope and NASA’s asteroid-hunting Lucy spacecraft, can see a bright flash as the dart hits Dimorphos and sends streams of rock and dirt into space. The observatories will track the pair of asteroids as they orbit the Sun to see if DART has changed the orbit of Dimorphos. In 2024, a European spacecraft named HERA will retrace Dart’s visit to measure the consequences of the impact.
Although according to Chabot, the desired nudge should change the position of the moonlight only slightly, adding up to a major change over time. “So if you were going to do this for planetary defense, you would do it five, 10, 15, 20 years before this technology would work,” she said. Even if Dart misses, the experiment will provide valuable insights, said NASA program executive Andrea Riley. “That is why we test. We want to do it now, not when there is a real need,” she said.
asteroid missions galore
Planet Earth is on an asteroid-chasing roll. NASA has about a pound (450 grams) of debris on its way from asteroid Bennu to Earth. Stash should arrive next September. Japan was the first country to receive asteroid samples, a feat achieved twice. China hopes to follow suit with a mission to be launched in 2025. Meanwhile, NASA’s Lucy spacecraft, after being launched last year, is headed for asteroids near Jupiter. Another spacecraft, the Near-Earth Asteroid Scout, is loaded into NASA’s new moon rocket awaiting liftoff; It will next year use a solar sail to fly over a space rock less than 60 feet (18 meters). In the next few years, NASA also plans to launch a census-taking telescope to identify difficult-to-discover asteroids that may pose a risk. An asteroid mission is grounded while an independent review board weighs its future. NASA’s Psyche spacecraft should have been launched this year to a metal-rich asteroid between Mars and Jupiter, but the team could not test the flight software in time.
Hollywood has churned out dozens of killer space-rock movies over the decades, including 1998’s “Armageddon,” which brought Bruce Willis to Cape Canaveral for filming, and last year’s “Don’t Look Up” in which Leonardo DiCaprio was shot. Played the Leading Role- Star Cast. NASA’s planetary defense officer, Lindley Johnson, figures she’s seen them all since 1979’s “Meteor,” her personal favorite “since Sean Connery played me.” While some sci-fi movies are more accurate than others, that said, entertainment always wins. The good news is that the coast appears to be clear for the next century, with no known threats. Otherwise, “It would be like in the movies, right?” NASA science mission chief Thomas Zurbuchen said. What is worrying, however, is that there are unknown dangers. Less than half of the 460-foot (140-meter) objects have been confirmed, with millions of smaller but still dangerous objects zooming in. “These threats are real, and what makes this time special is what we can do about it,” Zurbuchen said. DiCaprio’s character did in vain by not blowing up an asteroid as Willis’ character did — that would be a last, last-minute resort — or by begging government leaders to take action. If time permits, the best strategy may be to dart the dangerous asteroid out of our way.
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