articleThe Brief A piece of a SpaceX rocket appears to be on an unintentional collision course with the moon. The rocket stage is expected to strike the moon Wednesday near Einstein Crater at around seven times the speed of sound. It is the second known time that a piece of space debris has crashed into the moon. A large piece of a SpaceX rocket will likely make a crash landing this week — but it is not expected to smash into Earth soon. Big picture view:On Wednesday, the rocket’s upper stage is expected to slam into the moon near Einstein Crater with the force of three tons of TNT.