Scientists tracking an asteroid approaching Mars say that an impact with the Red Planet has become less likely.

Refined estimates of the asteroid's orbit were made using new observations from a telescope at the Calar Alto Observatory in Spain, according to the Near-Earth Object Program at NASA's Jet Propulsion Laboratory.

The impact probability fell to 2.5 percent, the NEO office said in Jan. 8 update posted on the NEO Web site.

The miss distance was holding steady at about 30,000 kilometers, or 18,600 miles.

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The asteroid, dubbed 2007 WD5, was discovered in late November by the NASA-funded Catalina Sky Survey in Arizona.

Odds of an impact had risen to about 4 percent by late December and scientists were excited about the possibility of observing a cosmic collision on Jan. 30.

The size of a football field, the asteroid could blast a half-mile-wide crater into the Martian surface.

The NEO program looks for and tracks asteroids and comets that could potentially be a hazard to Earth.