CAPE CANAVERAL, Fla. (AP) – A drifting SpaceX rocket is on a collision course with the moon after launching a pair of lunar landers more than a year ago.

The rocket's upper stage will unintentionally slam into the moon on Wednesday, carving out a crater and sending up a plume of dust and rubble that scientists – and skygazers – are eager to observe.

Space tracking expert Bill Gray predicts an impact of 5,400 mph (8,700 kph) – seven times the speed of sound – near Einstein Crater on the moon's sunlit western limb. With the action unfolding in the wee hours, the eastern portions of the United States and Canada, and much of South America should have the best views.