In 2017, astronomers projected an asteroid the size of a cruise ship would strike Japan sometime in the next decade. At this time, scientists and government officials from NASA and other space agencies gathered at an annual planetary defense conference in Tokyo. This group quickly devised a plan to knock the asteroid off its path toward Earth. Japan’s fate relied on a fleet of robotic spacecraft that would launch in the next few years.
In 2020, the world’s space agencies banded together, launching four ships toward the astroid that was known to bump into the earth. The ships, known as kinetic impactors, struck their targets precisely. Japan was spared a herculean evacuation effort, its cities and neighborhoods saved from annihilation.
None of these events really happened. It was a simulation, that officials carry on a regular basis. And deflecting an object from deep space on its way is the preferred method of protecting this planet by the scientists, which is the reason this was simulated. However, no one knows whether the technique will actually work. Never in history has our species tried to knock an asteroid away from our world.
The fact that it was never tried is about to change. On Wednesday at 1:21 a.m. Eastern time, NASA launched the Double Asteroid Redirection Test mission, or DART, from a U.S. Space Force base in California (it was Tuesday local time). A 1,200-pound, refrigerator-sized spacecraft will go around the sun to slam into a small asteroid named Dimorphos at 15,000 miles per hour next year. If the mission succeeds, it could show humanity’s ability to knock a potentially hazardous asteroid away from Earth.
The $324 million DART mission is unusual for NASA, a civilian agency that focuses mainly on exploration, climate monitoring, and hunting for signs of past life. While it coordinates with and relies on the U.S. Department of Defense for some activities, NASA has not traditionally been responsible for leading efforts to protect the United States — or Earth, for that matter — from any security threat. The DART mission is giving, to some degree, the responsibility to protect Earth to NASA.
NASA has been studying space rocks up close for decades. It has landed robots on the surface of Mars, plucked samples from a large asteroid named Bennu (which may threaten Earth in the 22nd century), and even deliberately crashed spacecraft into a comet and into the moon, all for the sake of science. But striking an asteroid hard enough to alter its orbit in space poses new challenges for the agency’s engineers and scientists.