According to NASA's Jet Propulsion Laboratory (JPL), asteroid 2012 DA14 is about 50 yards (45 meters) in diameter and will pass within a mere 17,200 miles (27,680 km) of the surface of the earth at about 2:30 pm EST on February 15, 2013.
Passing closer than some geosynchronous weather and communications satellites orbiting at 22,000 miles (35,800 km), asteroid 2012 DA14 will become the largest object ever observed by NASA passing so close to the earth.
"This is a record-setting close approach," said Don Yeomans of NASA's Near Earth Object Program at JPL. "Since regular sky surveys began in the 1990s, we've never seen an object this big get so close to Earth."
While "record-setting close," 2012 DA14's passage will still be safely above the International Space Station orbiting at no more than 225 miles (410 km) above the Earth.
"The odds of an impact with a satellite are extremely remote," noted Yeomans. "Almost nothing orbits where DA14 will pass the Earth."
While called "neither very large nor very small" by NASA's standards, asteroid 2012 DA14 would still pack quite a punch.
According to Yeomans, a similar sized object created the mile wide Meteor Crater in Arizona about 50,000 years ago and "something" estimated to have been about the size of 2012 DA14 exploded above Tunguska, Russia in 1908, leveling hundreds of square miles of forest.
But fear not, because Yeomans guarantees a miss. "2012 DA14 will definitely not hit Earth," he assured. "The orbit of the asteroid is known well enough to rule out an impact."
For your planning purposes, Yeomans estimates that asteroids the size of 2012 DA14 approach the Earth, on average, every 40 years, while actually hitting our planet only every 1,200 years or so.