NASA says a near-Earth asteroid was imaged by the Arecibo Radio Telescope in Puerto Rico and scientists ruled out an Earth impact for at least 100 years.

The space agency said data involving asteroid 2005 YU55 were obtained April 19-21 and allowed the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory to refine the space rock's orbit, ruling out any possibility of an Earth impact for a century.

The asteroid, approximately 1,300 feet in size, was about 1.5 million miles from Earth when the image was generated.

Steve Chesley of JPL's Near-Earth Object Program Office said prior to the Arecibo data, scientists had eliminated nearly all upcoming Earth flybys as possibilities of impact. "But there were a few that had a low remaining probability of impact," Chesley said. "After incorporating the data from Arecibo, we were able to rule impacts out entirely for the next 100 years."

With future observations, scientists say they may be able to plot the asteroid's orbit for an even longer period of time.

NASA detects and tracks asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," plots their orbits to determine if any could be potentially hazardous to Earth.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate.