The lunar dust environment is expected to be dominated by submicron-sized dust particles released from the Moon due to the continual bombardment by micrometeoroids, and due to plasma-induced near-surface intense electric fields. The Lunar Dust EXperiment (LDEX) is designed to map the spatial and temporal variability of the dust size and density distributions in the lunar environment onboard the upcoming Lunar Atmosphere and Dust Environment Explorer (LADEE) mission. LDEX is an impact detector, capable of measuring the mass of submicron sized dust grains. LDEX will also measure the collective current of the dust grains that are below the detection threshold for single dust impacts; hence it can search for the putative population of grains with radii on the order of ~ 0.1 μm lofted over the terminator regions by plasma effects. LDEX has been developed at LASP/CCLDAS and has a high degree of heritage based on similar instruments on the HEOS 2, Ulysses, Galileo, and Cassini missions. The LDEX flight model has been tested and calibrated at the dust accelerator facility of the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS). This talk will summarize the tested capabilities of LDEX, and make predictions for its measurements in lunar orbit based on our current theoretical models. LDEX is scheduled for launch in September 2013.