2nd NASA probe en route to moon on New Year's Day

By ALICIA CHANG | January 1, 2012 | 12:07 PM EST

This undated artist rendering provided by NASA on Dec. 21,2011 shows the twin Grail spacecraft mapping the lunar gravity field. The two probes are scheduled to enter orbit around the moon over New Year's weekend. (AP Photo/NASA, Jet Propulsion Laboratory)

PASADENA, Calif. (AP) — A day after a NASA spacecraft safely entered orbit around the moon, its twin was poised to do the same.

The duo are on a mission to study what's inside the moon by mapping its uneven gravity field.

On New Year's Eve, a probe named Grail-A fired its engine and was captured into lunar orbit. NASA hopes for a similar flawless performance from Grail-B on New Year's Day.

Once in orbit, the near-identical probes will spend two months tweaking their positions until they are circling 34 miles above the surface. They will begin collecting data in March.


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