A piece of a SpaceX rocket is about to hit the moon. A roughly five-ton piece of a SpaceX rocket that sent two lunar landers to the moon is about to join them, but not on purpose. Gray was the first to calculate that the object would hit the moon and has been tracking it since. To: know.your.whyThe Man In The Moon is going to be really PO'd...To: know.your.whyWhy slam a rocket into the moon when we landed so easily last time? There were 5 Apollo missions that deliberately crashed their S-IVB third stages into the moon to calibrate seismic instruments - Apollo 13, Apollo 14, Apollo 15, Apollo 16, and Apollo 17.