The asteroid, initially estimated to be about 1,300 feet in diameter, came within 4.2 million miles of Earth Sept. 16 but has only a 1-in-63,000 chance of impacting our planet when it returns in two decades, they said.
The short period of observations of the asteroid's orbit so far -- a path that takes is as far out as about three quarters of the distance to Jupiter's orbit -- means the future orbital path is still uncertain.
But the near-Earth asteroid should be easily observable in the coming months allowing the initial orbit calculations to be improved, scientists said, most likely resulting in a dramatic reduction, or even complete elimination, of any risk of Earth impact.
"To put it another way, that puts the current probability of no impact in 2032 at about 99.998 percent," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "This is a relatively new discovery. With more observations, I fully expect we will be able to significantly reduce, or rule out entirely, any impact probability for the foreseeable future."