Nearly 40 years have passed since the last Apollo missions investigated the mysteries of the lunar atmosphere and the question of levitated lunar dust. The most important questions remain: what is the composition, structure and variability of the tenuous lunar exosphere? What are its origins, transport mechanisms, and loss processes? Is lofted lunar dust the cause of the horizon glow observed by the Surveyor missions and Apollo astronauts? How does such levitated dust arise and move, what is its density, and what is its ultimate fate? The Lunar Atmosphere and Dust Environment Explorer (LADEE) is a small spacecraft mission being developed and led by Ames Research Center. It is equipped with a neutral mass spectrometer, a dust detector and an ultraviolet/visible spectrometer. It's goal: to assess the compositional makeup and variability of the Moon's thin atmosphere, and to establish once and for all if a mysterious dust lofting phenomenon occurs.