By Clara Moskowitz, Source: Scientific American

Nasa
When a meteor exploded over Chelyabinsk, Russia in February, the world’s space agencies found out along with the rest of us, on Twitter and YouTube. That, says former astronaut Ed Lu, is unacceptable—and the United Nations agrees. Last week the General Assembly approved a set of measures that Lu and other astronauts have recommended to protect the planet from the dangers of rogue asteroids.

The U.N. plans to set up an “International Asteroid Warning Group” for member nations to share information about potentially hazardous space rocks. If astronomers detect an asteroid that poses a threat to Earth, the U.N.’s Committee on the Peaceful Uses of Outer Space will help coordinate a mission to launch a spacecraft to slam into the object and deflect it from its collision course.

Lu and other members of the Association of Space Explorers (ASE) recommended these steps to the U.N. as a first step to address at the long-neglected problem of errant space rocks. “No government in the world today has explicitly assigned the responsibility for planetary protection to any of its agencies,” ASE member Rusty Schweickart, who flew on the Apollo 9 mission in 1969, said Friday at the American Museum of Natural History. “NASA does not have an explicit responsibility to deflect an asteroid, nor does any other space agency.” The ASE advocates that each nation delegate responsibility for dealing with a potential asteroid impact to an internal agency—before the event is upon us.

The next step in defending Earth against dangerous asteroids is to find them, Lu said. “There are 100 times more asteroids out there than we have found. There are about 1 million asteroids large enough to destroy New York City or larger. Our challenge is to find these asteroids first before they find us.”

Early warning is important because it increases the chance of being able to deflect a threatening asteroid once it is found. If a spacecraft struck an asteroid 5 or 10 years before the rock was due to hit Earth, a slight orbital alternation should be enough to make it pass Earth by; if the asteroid wasn’t detected soon enough, evacuating the impact zone may be the only option available. “If we don’t find it until a year out, make yourself a nice cocktail and go out and watch,” Schweickart quipped.

The B612 Foundation, a non profit Lu founded to address the problem of asteroid impacts, is developing a privately funded infrared space telescope called Sentinel, which it hopes to launch in 2017. The telescope would begin a systematic search for hazardous near-Earth objects.

The ASE astronauts are also asking the United Nations to coordinate a practice asteroid deflection mission to test out the technologies for pushing a rock off course should the need arise. The meteor in Chelyabinsk, which injured 1,000 people but killed none, was an ideal warning shot across the bow, said American Museum of Natural History astronomer Neil deGrasse Tyson, who hosted Friday’s event—now, it’s time for Earth’s citizens to take action. Lu agreed: “Chelyabinsk was bad luck,” he said. “If we get hit again 20 years from now, that is not bad luck—that’s stupidity.”