New mission: Defend Earth from asteroids
It was 2017, and astronomers projected an asteroid the size of a cruise ship would strike Japan sometime in the next decade.
Scientists and government officials from NASA and other space agencies, gathered at an annual planetary defense conference in Tokyo, hastily devised a plan to knock the asteroid off its path toward Earth. The island’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 menacing space rock. The ships, known as kinetic impactors, struck their targets head-on. Japan was spared a herculean evacuation effort, its cities and neighborhoods saved from annihilation.
None of these events really happened. It was a simulation, the kind of tabletop role-playing exercise that officials conduct on a regular basis. And deflecting an object from deep space on its way to a deadly rendezvous with Earth has become a preferred solution at these practice drills for protecting the planet. Yet no one knows whether the technique will actually work. Never in human history has our species tried to knock an asteroid away from our world.
That is about to change. On Wednesday at 1:21 a.m. Eastern time, NASA launched the Double Asteroid Redirection Test mission, or DART, from Vandenberg Space Force Base near Lompoc (Santa Barbara County). A 1,200pound, refrigerator-size spacecraft will trek around the sun to slam into a small asteroid named Dimorphos at 15,000 mph next year. If the mission succeeds, it could demonstrate for the first time humanity’s ability to punch a potentially hazardous asteroid away from Earth.
“We’re doing this work and testing this DART capability before we need it,” Lindley Johnson, NASA’s chief of planetary defense, said. “We don’t want to be flying an untested capability when we’re trying to save a population on the Earth’s surface.”
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 in our solar system. 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.
That changed in 2005, when Congress assigned the agency the imperative of protecting the planet from dangerous objects that orbit the sun and have the bad habit of occasionally crossing paths with our world. That includes tracking tens of thousands of so-called near-Earth asteroids large enough to wreak catastrophic damage. Lawmakers assigned NASA the task of cataloging 90% of the total expected amount of these space rocks, but it has missed that goal.
The test, if successful, will give NASA a confirmed weapon in its planetary-defense arsenal.