Regolith Buffer Hopper
Anti-Bridging Vibration-Assisted Surge Hopper
A regolith buffer hopper is a conical surge vessel that converts intermittent hauler deliveries into a continuous, metered discharge of 10 to 200 kilograms per hour for downstream processing. Granular flow is problematic on the Moon, where one-sixth gravity reduces the downward discharge force while vacuum conditions and interlocking, irregular grain shapes dramatically increase regolith cohesion, promoting the formation of flow-blocking arches. To ensure reliable mass flow, the 300-liter stainless steel hopper utilizes steep 70-degree walls, a low-friction liner, and a sealed 50-hertz eccentric vibrator motor calibrated to disrupt bridging while isolating internal bearings from abrasive lunar dust.
Surge hopper that buffers the batchy output of excavators/haulers (~100 kg per dump) into the steady-state input rate of downstream conveyors and processors, with anti-bridging vibration to prevent the cohesive fine fraction of lunar regolith from arching and blocking flow.
Purpose
Smooth the rate mismatch between intermittent excavator deliveries and continuous downstream processing, allowing both to operate near optimum independently, and provide local storage when downstream stages are in maintenance.
Context
Located at fixed plant inlet; receives material from L3-ISR-TRANS-VEH haulers or directly from L3-ISR-EXC-BWE; outputs metered flow to L3-ISR-TRANS-CONV conveyors. Vibration motors prevent regolith bridging — a well-documented failure mode in lunar simulant handling.
Principles
- ▸Mass-flow vs. funnel-flow hopper geometry: mass-flow (steep walls, all material moves) preferred for cohesive material; funnel-flow (only center moves) causes bridging
- ▸Lunar regolith cohesion arises from electrostatic attraction + interlocking irregular grain shapes — bridging arches form easily
- ▸Anti-bridging methods: vibration (most common), aeration (uses gas), screw activation, knockers, ultrasonic
- ▸Hopper sizing: typical 1-4× hauler-payload capacity (e.g., 200-400 L for 50 kg hauler)
- ▸Discharge metering via screw, rotary valve, or vibratory tray feeder
- ▸Wall material: hardened stainless or PTFE-lined to reduce wall friction
Typical implementations
- ▸Terrestrial industrial silo hoppers (cement, chemicals, food)
- ▸NASA KSC granular mechanics test fixtures
- ▸Lunar simulant production hopper at CSM (Colorado School of Mines)
- ▸Phoenix Mars Lander sample-delivery hopper heritage
Lunar considerations
- ▸Lunar fine cohesion in vacuum is greater than terrestrial simulant — vibration intensity must be calibrated for actual regolith
- ▸Vacuum-rated vibrator motors (BLDC with eccentric mass)
- ▸Dust ingress to vibrator bearings — sealed housings
- ▸1/6 g reduces gravitational discharge force — narrower hopper angle compensates
- ▸Robotic access ports for inspection and de-bridging via L1-MNT
- ▸Multi-hopper parallel configuration for higher capacity and redundancy
Specifications
Functional
| primary function | Buffer regolith between intermittent intake and continuous downstream flow |
| inputs | Regolith batch dumps from L3-ISR-TRANS-VEH or L3-ISR-EXC-BWE, Vibrator power from L1-PDM, Metering commands from L3-ISR-CTRL-PROC |
| outputs | Metered regolith flow to L3-ISR-TRANS-CONV, Inventory level + flow telemetry, Anti-bridging vibration status |
| capacity l | 300 |
| capacity kg regolith | 500 |
| discharge rate kg per hour range | 10, 200 |
| discharge rate accuracy percent | 5 |
| wall angle from vertical deg | 70 |
| vibration frequency hz | 50 |
| vibration power w | 30 |
| max dust residence time days | 7 |
Physical
| mass kg | 40 |
| dimensions | 1.0 m height × 0.8 m diameter (conical hopper) |
| materials | 316L stainless steel hopper body, PTFE wall liner to reduce friction, Vibrator motor (BLDC with eccentric mass), Rotary valve discharge metering, Capacitance level sensor, Dust-tight access port covers |
| operating temperature c | -40, 80 |
| vacuum compatibility | True |
Operational
| power consumption w | 30 |
| thermal range c | -40, 80 |
| lifetime years | 20 |
| mtbf hours | 80000 |
Interfaces
Provides
- Metered regolith feed
- Alternative direct feed to sieve
- Inventory and flow telemetry
Requires
- Regolith batch deliveries
- Direct dump from excavator (alt path)
- Vibrator and rotary valve (~30 W)
Cite this entry
Lunar Ark Codex. "Regolith Buffer Hopper" (L3-ISR-TRANS-HOP). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ISR-TRANS-HOP
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.