The National Aeronautics and Space Administration's Jet Propulsion Laboratory at the California Institute of Technology said tracking measurements of asteroid 2007 WD5 from four different observatories indicate a significantly reduced probability -- to .01 percent -- that it will make impact with Mars, effectively ruling out a possible collision with the planet.

The agency's best estimate as of Thursday was that 2007 WD5 will pass about 16,000 miles from the planet's center at around 1 p.m. EST on Jan. 30.

"With 99.7 percent confidence, the pass should be no closer than 4,000 km (2,485 miles) from the surface," the lab said in a release.