NASA's 2009 LCROSS mission discovered ice on the moon's South Pole. Via Creative Commons

The moon-bound craft will have two more opportunities Friday morning reports the Los Angeles Times. GRAIL A and B will reach the moon on Dec. 31 and Jan. 1 respectively. The two identical probes will separate and orbit the moon for three months.

From the Los Angeles Times:

Scientists predict the mission will provide a comprehensive map of the moon's gravitational field, allowing them to better calculate the composition of its crust, mantle and core and adding to their understanding of the evolution of the rocky planets.

The GRAIL mission follows the LCROSS moon exploration mission in 2009, which searched the moon's South Pole for evidence of water. It also incepts NASA's newest era: space exploration without humans aboard.

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