Abstract:
This paper examines the engineering challenges of closed-loop life support systems (CLSS) for lunar/Martian habitats and deep-space missions. We analyze the Sabatier reaction's efficiency in converting CO₂ to O₂ and H₂O, compare microbial fuel cells (MFCs) with traditional electrolysis for water recovery, and discuss solid waste processing via pyrolysis. Thermal control systems integrating phase-change materials (PCMs) and variable-emittance coatings are evaluated for energy efficiency.
Technical Depth:
Oxygen Recycling: The Sabatier process (CO₂ + 4H₂ → CH₄ + 2H₂O) operates optimally at 300–400°C with nickel catalysts, achieving 98% conversion efficiency. However, methane byproduct management requires additional catalytic oxidation stages to prevent atmospheric contamination.
Water Recovery: MFCs demonstrate 65–75% efficiency in breaking down urine/wastewater into H₂O and electricity, outperforming electrolysis (40–50% efficiency) but requiring complex biofilm maintenance.
Solid Waste: Pyrolysis converts fecal matter into char (25–30% mass) and syngas (70–75% energy recovery), with residual organics requiring bioreactor processing.
Innovation:
A hybrid CLSS integrating Sabatier reactors, MFCs, and pyrolysis units reduces resupply needs by 82% for a 6-person Mars habitat. Thermal modeling shows PCMs (e.g., paraffin wax) reduce temperature swings by 40% during lunar night cycles.
