Researchers believe the robotic explorer vaporized upon contact because of its high orbiting speed of 3,600 mph, possibly smacking into a mountain or side of a crater. As of late Thursday afternoon, the spacecraft was flying 300 feet above the lunar surface. Its altitude had been lowered on purpose to ensure a crash by Monday.
LADEE — short for Lunar Atmosphere and Dust Environment Explorer — was launched in September. It completed its main science mission last month and was on overtime.