NASA has had twin spacecraft orbiting the moon for a long time called the GRAIL mission probes. GRAIL stands for Gravity Recovery and Interior Laboratory. The twin spacecraft are called Ebb and Flow. The two spacecraft performed their missions as expected and are no longer needed.
Rather than leave those two spacecraft orbiting our moon aimlessly, NASA plans to crash the spacecraft in a controlled descent and impact onto a mountain near the Moon’s North Pole at about 2:28 PM PST on Monday, December 17. The spacecraft will hit the surface of the moon at 3760 mph. Unfortunately, the impacts will happen an area of the moon that will be shadowed at the time so no images will be available.
NASA says the reason it is destroying the spacecraft is because they are in a low orbit and have low fuel levels making them non-functional for any further scientific operations. Both spacecraft performed their primary and extended science missions successfully, generating the highest resolution gravity field map of any celestial body in our solar system. NASA says that information the two spacecraft gathered will help provide a better understanding of how Earth and other rocky planets in our solar system formed.