By Elizabeth Landau, CNN

A pair of robotic twins that have been diligently mapping the moon this year will go out with a bang Monday, around 5:28 p.m. EST.

The Gravity Recovery and Interior Laboratory (GRAIL) probes Ebb and Flow will crash into a mountain on the moon Monday afternoon, ending a fruitful mission to study the surface and composition of the moon.

"Scientifically we are learning a great deal about not only the moon but about the early evolution of terrestrial planets," said principal investigator Maria Zuber of the Massachusetts Institute of Technology at a press conference Thursday.

Thanks to GRAIL, scientists now have the "highest-resolution gravity field map of any celestial body," NASA said. That means the probes have been making a high-quality map of the gravitational field of the moon, which give scientists unprecedented insight into what's below the surface and how the moon may have formed.

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