Regolith Heating Module
Solar-Concentrator / Resistive-Heater Regolith Thermal Stage
The Regolith Heating Module is a thermal processing stage that uses concentrated solar power and resistive heating elements to raise icy regolith from permanently shadowed region temperatures of approximately 88 K above the 150 K vacuum sublimation threshold. Liberating water in the lunar environment is constrained by the vacuum sublimation enthalpy of 2.83 MJ/kg and severe heat loss to the 88 K surroundings, which also induces thermal shock in heating components. Delivering a rated thermal power of 5 kW, the 25 kg unit processes 50 kg of regolith per hour, capturing water vapor released at low partial pressures of roughly 1 Pa.
Hybrid solar-concentrator + resistive-heater module that raises icy regolith (excavated by L3-ISR-EXC-BWE/AUG or in-situ in 'thermal mining' mode) from ~88 K PSR temperature above the water sublimation threshold (~150 K at vacuum), liberating water and other volatiles for downstream capture.
Purpose
Provide the high-power, high-temperature input that drives the entire ice-extraction chain — efficiently using concentrated solar energy from peaks-of-eternal-light or stored thermal energy from L2-ESS-THRM to overcome the energy cost of water sublimation (~2.83 MJ/kg).
Context
Receives icy regolith from L3-ISR-EXC-AUG / L3-ISR-EXC-BWE; output (water vapor + dry regolith) feeds L3-ISR-ICE-SUBL chamber and L3-ISR-ICE-COND condenser. Can also operate in 'in-situ thermal mining' mode atop the regolith surface (Paragon ICICLE-style).
Principles
- ▸Water-ice sublimation enthalpy at vacuum: ~2.83 MJ/kg — sets minimum energy input per kg water produced
- ▸Regolith specific heat ~0.84 kJ/kg·K → heating 1 kg of regolith from 88 K to 200 K requires ~94 kJ in addition to phase-change energy
- ▸Solar concentrator with ~1000× concentration on a heliostat-aimed beam delivers ~1000 W/m² × A_collector at sub-PSR locations
- ▸Resistive heaters (PBN, Inconel-clad) provide consistent thermal input at night or in PSR — typically 1.5–10 kW per heating module
- ▸Sealed thermal stage with insulated walls retains heat — sublimated water is the only mass leaving
- ▸Heat-transfer enhancement via conducting fins or particle agitation increases regolith throughput
Typical implementations
- ▸Paragon SDC ICICLE 'tent' with concentrated solar + secondary optics for in-situ heating (ICES-2024-109)
- ▸NASA Glenn LADI continuous auger heating (NTRS 20230013485, 2023)
- ▸LUWEX project (ScienceDirect Adv Space Res 2026) — integrated lunar water extraction + capture demonstration
- ▸Microwave heating concept (PMC 12308065, 2025) — massive water from cryogenic regolith
- ▸Thermal mining of volatiles in lunar regolith simulant (ScienceDirect Planetary Space Sci 2022)
- ▸ESA PROSPECT instrument heating (Luna-27 prospecting payload)
Lunar considerations
- ▸PSR ambient ~88 K — thermal shock to heater elements requires gradual warm-up cycles
- ▸Sublimated water vapor at very low partial pressure (~1 Pa) — must be captured immediately to avoid loss
- ▸Solar concentrator only available at peaks of eternal light; PSR heating requires beamed power or stored thermal energy
- ▸Heat loss to surrounding cold regolith is significant — well-insulated thermal stage essential
- ▸Long-life heater elements: PBN or Inconel-clad nichrome rated for 1000+ cycles up to 800 °C
- ▸Process integration with electrolyzer (L3-ESS-FC-ELEC) closes the loop: H2O → H2 + O2 → consumed → H2O
Specifications
Functional
| primary function | Heat icy regolith above water sublimation threshold |
| inputs | Icy regolith feedstock from L3-ISR-EXC-AUG or L3-ISR-EXC-BWE, Electrical power from L1-PDM (resistive heater), Concentrated solar (when available) from L2-PWR-SOL or dedicated heliostat, Stored thermal from L2-ESS-THRM-CONV alternate route |
| outputs | Heated regolith with mobilized vapor to L3-ISR-ICE-SUBL chamber, Direct vapor stream to L3-ISR-ICE-COND, Process telemetry: regolith temperature, water yield, energy input |
| rated thermal power kw | 5 |
| peak thermal power kw | 10 |
| operating temperature c | 150, 350 |
| regolith throughput kg per hour | 50 |
| water yield kg per hour at 2 pct ice | 1.0 |
| specific energy kwh per kg water | 3.5 |
| design cycles | 5000 |
| heating modes | solar-concentrator, resistive, microwave-augmented |
Physical
| mass kg | 25 |
| dimensions | 600 × 400 × 400 mm reactor module + external concentrator/heater |
| materials | Inconel 718 reactor vessel inner liner, Stainless 316L outer shell, PBN (pyrolytic boron nitride) heater elements, Aerogel + multi-layer insulation between liners, Tungsten carbide regolith-agitator surfaces, Sapphire viewports for optical concentrator coupling |
| operating temperature c | -180, 350 |
| vacuum compatibility | True |
| ultimate load g | 6 |
Operational
| power consumption w | 5000 |
| thermal range c | -180, 350 |
| lifetime hours | 5000 |
| mtbf hours | 3000 |
Interfaces
Provides
- Water + volatile vapor stream
- Vapor stream for condensation
- Process telemetry and yield
Requires
- Icy regolith feedstock
- Up to 10 kW heater power
- Concentrated solar for thermal mining mode
- Cold-side rejection for heater electronics
Cite this entry
Lunar Ark Codex. "Regolith Heating Module" (L3-ISR-ICE-HEAT). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ISR-ICE-HEAT
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.