The U.S. space agency NASA says the twin spacecraft of its lunar-mapping mission have completed their assignment and have been deliberately crashed into the rim of a moon crater.

Officials say the probes named Ebb and Flow hit the moon's surface Monday afternoon, eastern U.S. time, in the last phase of NASA's GRAIL mission. The twin spacecraft hit a mountain near the lunar north pole, bringing their successful mission to an end.

Ebb and Flow were purposely sent crashing into the moon because they no longer had enough altitude or fuel to continue operating.

Afterward, NASA said it had dedicated the impact site in honor of mission team member Sally Ride, the first American woman in space who died earlier this year. By design, the crash site was far away from the Apollo moon landings and other historical sites.

The two spacecraft are not the first to crash into the moon. NASA's GRAIL mission web page says 12 U.S., Soviet and Japanese spacecraft crashed into the moon's surface between 1959 and 1993.

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