“Last year, NASA launched the Double Asteroid Redirection Test (DART), which is a car-size box outfitted with solar panels. It’s currently on its way to a 160-meter asteroid called Dimorphos. In the fall, DART will crash into Dimorphos at 24,000 kilometers an hour (about 15,000 miles per hour).
Dimorphos is a “moonlet” asteroid, which means it orbits a larger asteroid named Didymos, much like the moon orbits the Earth. If all goes according to plan, the collision will change its orbit, proving that it’s possible to redirect a big hunk of rock in the middle of space. (The larger asteroid’s gravitational pull will help ensure that Dimorphos doesn’t fly off in a new direction, say, toward Earth.)
DART is the definition of a long shot. “This has never been tried before,” Andrews explains on Unexplainable. If it doesn’t work, that doesn’t mean we couldn’t ever deflect an asteroid. But perhaps it will take more force than DART can supply.”
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“If DART works, NASA can build a similar strategy into its anti-asteroid game plan. If they spot an asteroid heading toward Earth, “they can send a precursor mission to observe it beforehand,” Andrews says. In those initial observations, scientists can study the asteroid’s composition and make calculations for how much force it will take to deflect the rock. “You could then send a DART-like mission.”
The problem of asteroids potentially crashing into the Earth is not yet solved. Still, a couple hundred years in the future, it’s possible that scientists like Fast will be hailed as forward-thinking heroes who laid the groundwork of a planetary defense system. “There’s no greater gift that America’s space agency can give” than protection for humans of the future, Fast says.
Even though these disasters might not arrive in our lifetimes, we can still feel good about the progress being made. It’s a way to be good ancestors to the generations that follow us. On the long list of problems to solve and disasters to mitigate, maybe we can actually solve one.”
https://www.vox.com/science-and-health/2022/1/26/22879970/nasa-asteroids-comets-dart-dont-look-up