NASA smacked an asteroid with a spacecraft. Watch what happened next. - Tech News Digest

Saturday, 4 March 2023

NASA smacked an asteroid with a spacecraft. Watch what happened next.

Hubble documenting DART asteroid crash

The 1998 blockbuster Armageddon was about a fictional last-ditch attempt by NASA to stop a speeding asteroid headed toward Earth.

Now, 25 years later, the U.S. space agency has a movie showing just what asteroid-kicking really looks like.

During the immediate aftermath of the DART mission — NASA's first asteroid target practice — the Hubble Space Telescope captured the hour-by-hour changes as the space rock cast off over 1,000 tons of debris. The time-lapse, shown below, depicts the rock and dust spraying out into a complex pattern for days after the impact.

"We've never witnessed an object collide with an asteroid in a binary asteroid system before in real time, and it's really surprising," said Jian-Yang Li, who led a study published in the journal Nature about the mission, in a statement. "Too much stuff is going on here. It's going to take some time to figure out."

Hubble was able to record a much wider view than could be seen by the Italian LICIACube satellite, which flew past the wreckage mere minutes after DART's hit.

NASA deliberately crashed a spacecraft into a harmless asteroid through the Double Asteroid Redirection Test, better known as DART, on Sept. 26, 2022. The exercise tested the space agency's capability to thwart a hazardous space rock in the future, should one be on a collision course with Earth.

A couple of weeks later, astronomers reported that the experiment was effective, giving Earthlings a bit of peace of mind. Scientists used ground-based telescopes to measure how the impact to Dimorphos, a smaller asteroid orbiting a larger one, Didymos, changed its orbit. They could see that its travel time around Didymos had shortened by about 32 or 33 minutes.

Five papers published in the journal Nature on March 1 confirm the mission worked and begin to answer why the smash was so successful at changing the asteroid's trajectory. The experiment vastly exceeded their hopes of a 10-minute reduction in the orbit time.

"Too much stuff is going on here. It's going to take some time to figure out."

The nameless spacecraft, about 1,300 pounds, carried no explosives. Its "weapon" was its own body and the sheer force of plowing into an asteroid at 14,000 mph. Scientists have likened the mission to running a golf cart into the Great Pyramid of Giza.

But it was the slap heard 'round the solar system.

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The key was that the spacecraft wasn't the only thing to give Dimorphos a push, according to the new research. When the asteroid flung out pulverized rock, it sustained a kickback like a shooter feels after firing a gun, with almost four times the momentum of the initial hit.

Modeling the DART asteroid hit
A NASA research team modeled how the DART spacecraft hit the asteroid Dimorphos. Credit: NASA / Johns Hopkins APL

Hubble's movie, free of cameos from Bruce Willis and Ben Affleck, shows three primary stages following the crash: the forming of a blast cone, a pinwheel of debris surprisingly tied to the asteroid's companion, Didymos, and a tail swept behind the asteroid.

The first post-impact snapshot in the time-lapse captures debris flying away over 4 mph — fast enough to break free of the asteroid's gravitational pull. About 17 hours after the hit, the blast cone begins to morph into different structures, including spiraling pinwheels.

"When I first saw these images, I couldn't believe these features," Li said in a statement. "I thought maybe the image was smeared or something."

Then, the asteroid grows a comet-like tail of debris. In a baffling turn of events, it splits into two tails for a few days.

Scientists say the DART crash will give them many more years of research as they continue to observe the debris and await follow-up missions. The European Space Agency's Hera spacecraft will show up at Dimorphos in three years to get a close look at the crater.

The mission was an important first step in an international effort to prepare for these types of existential threats, NASA administrator Bill Nelson said last year.

"NASA is trying to be ready for whatever the universe throws at us," he said.




via Tech News Digest

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