The U.S. space agency is a decade behind in meeting a congressional mandate to detect meteors capable of destroying a city, and needs a telescope in space to improve tracking, the nation’s top science officials said.
NASA’s leaders said most large asteroids that may trigger a global catastrophe have been found and tracked, and an impact within the next several centuries is unlikely. Smaller objects are harder to track, arrive more often and are less lethal.
“Unfortunately, the number of undetected potential ‘city killers’ is very large,” John Holdren, assistant to President Barack Obama for science and technology, said today at a hearing of the House Science, Space and Technology Committee. “It’s in the range of 10,000 or more.”
A meteor blast over Russia Feb. 15 put fresh focus on efforts to send a spacecraft into an asteroid to show incoming objects can be knocked off a collision course. The Air Force wasn’t aware of the meteor until it streaked toward Earth, General William Shelton said. He declined to elaborate.
Defending the planet against asteroids, a focus of former astronauts, astronomers and amateur hobbyists, generated worldwide discussions this year as the largest meteor to explode near Earth in a century blew out windows and injured 1,200 people near the central Russian town of Chelyabinsk.
Congress asked NASA to find and track 90 percent of the asteroids that are 140 meters or greater in size by 2020. Under current funding, the goal won’t be met until 2030, Charles Bolden, the NASA administrator, said today.
“Smaller objects, such as the recent impact in Russia will always be difficult to detect and provide adequate warning,” Bolden said. But “if you really want to find and detect near-Earth objects early enough that we can do something, you need to have something in space,” and that would cost billions of dollars, he said.
Scientists are powerless if a large asteroid big enough to threaten civilization was found to be on course to collide with Earth in a few weeks, Bolden said. “The answer to you, is, if it’s coming in three weeks, pray,” he said.
Bolden backed the efforts of the non-profit group B612 that is seeking $400 million to launch a telescope into the orbit of Venus to find space objects that could collide with Earth. Getting a telescope in space is necessary to find meteors such as the one that hit in Russia. It was difficult to find because it came from the direction of the sun, Holdren said.
“We did detect it, at the time,” Shelton, head of the Air Force Space Command in Colorado, told lawmakers. “It wasn’t predicted.”
The blast in the remote Chelyabinsk region was the largest recorded since 1908, when a meteroite flattened more than 800 square miles (2,100 square kilometers) of Siberian forest.
A space object, if it’s big enough and hits in the right spot, could destroy a city or worse. Scientists blame an asteroid more than 6 miles in diameter for wiping out the dinosaurs 66 million years ago.