Abstract Vacuum ultraviolet (VUV) irradiation charges lunar regolith and may contribute to electrostatic dust mobilization, but meter‐scale laboratory constraints remain limited. We developed a meter‐scale deuterium‐lamp‐array VUV system that combines optical‐path superposition and stable array stitching to produce a controlled lunar‐relevant photon field for dust‐bed charging. Simulations and measurements show a centrally enhanced irradiance field, with a peak intensity of 0.73 W/m2 and stable output exceeding 0.35 W/m2. We measure the bed‐scale average surface potential of <100 μm lunar dust simulant under high vacuum, which reaches 3.655 V after 60‐min VUV exposure. Spatially heterogeneous potential distributions indicate charge retention and redistribution within the insulating granular bed. A single usable vertically mounted quartz crystal microbalance channel records an apparent mass loss of 23.42 ng under 45‐min VUV irradiation. These measurements constrain meter‐scale dust‐bed charging and local apparent mass change under lunar‐relevant VUV irradiation.