NASA’s Lunar Prospector spacecraft was deliberately crashed into the Moon’s south pole.
Launched aboard an Athena II rocket on January 7, 1998, the Lunar Prospector’s primary goal was to map the moon’s polar regions and analyze the surface’s composition. It was thought that there might be hydrogen deposits at the Lunar south pole. Once the mission came to its end, the Lunar Prospector was crashlanded there in the hopes that its impact would shoot out a plume of the theorized hydrogen, confirming its existence. The crashlanding was a success, but unfortunately, no plume was visible, and the theory was ultimately rejected.