NASA: Asteroid flyby next week will be closest for a space rock so large

A close encounter of the rocky kind is set for Feb. 15, when an office-building-size asteroid will speed past Earth faster than a bullet and closer than some communications satellites.

It will be the nearest recorded brush with a space rock so large, NASA scientists said Thursday.

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(The Washington Post/NASA) - A chunk of rock about half the length of a football field — travelling at almost 5 miles per second — will pass about 17,200 miles from Earth on Friday.

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The good news: There’s no chance of an impact. At its closest, asteroid 2012 DA14 will pass about 17,000 miles above Earth.

The bad news: A million other potentially dangerous — and unknown — city-killing space rocks are out there, and one of them could be on a collision course with Earth. Critics say NASA and other space agencies are not doing enough to scan for these threats.

“It’s like Mother Nature sending a warning shot across our bow,” said Don Yeomans, who tracks asteroids for the Jet Propulsion Laboratory in Pasadena, Calif.

Satellite operators said they were monitoring the asteroid but expected it to safely cruise through a belt of satellites that are about 23,000 miles up.

“We’re watching the situation, but there’s not a giant concern,” said Alex Horwitz, spokesman for Intelsat, which operates about 50 communications satellites.

The Air Force, meanwhile, is leaving the tracking to NASA.

An astronomer in Spain discovered the asteroid a year ago. Small, dim and speedy, it was a “slippery target” as it moved across a background of stars, said Jaime Nomen of the La Sagra Observatory in southern Spain.

NASA-funded scientists then ran the numbers: The asteroid was about 150 feet wide. Its closest approach will occur at 2:24 p.m. Eastern time on the 15th. On the night side of the planet — mainly Asia and Australia — observers with small telescopes might see a pinpoint streaking at the rapid clip of two moon-widths per minute.

Further observations refined the asteroid’s path. It cruises around the sun in an orbit almost identical to Earth’s. Our year is 365 days. Its year is a day longer. Like a drunk driver weaving across lanes, asteroid 2012 DA14 crosses paths with Earth twice a year, at varying distances.

Despite these opportunities for disaster, scientists tracking the asteroid are confident 2012 DA14 won’t collide with us for at least the next century, which is as far as they’ve been able to project its path. Next week’s approach is the closest during that time.

NASA began rigorously scanning the sky for cosmic hazards only in 1998, when Congress told it to. Agency scientists said Thursday they are confident their network of ground and space telescopes have found at least 95 percent of potentially planet-killing asteroids, those a half-mile wide or more. None of these monsters is headed toward Earth, Yeomans said.  

But the agency has done much worse identifying smaller threats, said Ed Lu, a former NASA astronaut. Lu spearheads the B612 Foundation, which last year began raising private funds to build an asteroid-spotting space telescope.

“Saying we’re only going to find the civilization-killers is a [sub-par] threshold,” Lu said. “We can do better than that.”

Lu said that so far the human race has spotted only about 1 percent of the smaller, but still dangerous, asteroids near Earth.