Vibration-assisted granular flow under simulated lunar conditions: parabolic flight validation of lunar regolith feed system
Year: 2026
Type: article
Abstract: Reliable transport of granular materials through hoppers is difficult in reduced gravity, because the gravitational driving force is diminished while cohesion is not. We report parabolic-flight experiments testing whether vertical vibration keeps a cohesive lunar highlands simulant (ICN-LHT-1) flowing from conical hoppers into rotary pocket feeders under simulated lunar gravity (0.16 g) and vacuum (27–60 Pa). Eight parallel hopper–feeder assemblies spanned four axisymmetric outlet geometries (11–45 mm diameter, 46.5–90° wall angles). Over 60 lunar-gravity parabolas (480 experiments), the flow response was binary: discharge was sustained in all 330 vibration-on experiments with functioning feeders (measured dimensionless acceleration Γ = 3.4–24) and arrested within seconds in 80 of 84 vibration-off experiments ( p < 0.001). In 1 g ground tests with the same hardware, flow also stopped without vibration: the 11 mm outlet did not flow, and the 17.5 and 30 mm outlets flowed at first and then clogged. At 0.16 g, no outlet discharged beyond the residual material held in the feeder pockets. Reactivating vibration restored flow without intervention. The delivered mass flow rate (0.3–1.0 g/s) was set primarily by the feeder speed. It did not differ significantly between outlet geometries, increased with Γ, and was on average 21% lower at 0.16 g than in 1 g ground tests with identical commands, consistent with looser packing of material into the pockets of the discharging pocket feeder in reduced gravity. These results bound the vibration intensity required for continuous feeding of this simulant at lunar gravity (Γ cr ≤ 3.4, i.e. a peak acceleration of 5.5 m/s² suffices for sustained flow) and provide critical design data for lunar regolith handling systems.
Source: Space and Planetary Resources
Institution: Colorado School of Mines
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,990
OpenAlex ID: W7136961612