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Description
Lunar night survival is a defining constraint on commercial micro-rover missions. Non-polar surface temperatures can fall to approximately 92 K, well below the storage limits of typical rover electronics and batteries, motivating approaches that do not rely on radioisotope heating.
This work evaluates the technical feasibility of a passive multilayer-insulation (MLI) shelter for a 5 kg-class micro-rover under non-polar lunar conditions. Following a tailored Phase-A systems-engineering approach, it combines a one-dimensional regolith model, which screens shelter reflectivity, deployment time and removal time to identify candidate operating windows, with a two-dimensional planar cross-sectional finite-element model that evaluates selected deployment timings and predicts internal temperatures for a two-compartment rover representation. Results are evaluated against published electronics and battery temperature limits, and contextualised by a functional decomposition, a traceable requirement set, and a weighted multi-criteria trade-off accounting for imported mass, stowed volume and the operational deployment window.
Shelter configuration and nominal MLI layer count strongly influence the modeled compartment minimum. At 15 MLI layers, the best sampled hemi-spheroidal case is approximately 24 K warmer than the best sampled box case, although these occur at different deployment times. The configurations differ in external radiating area and support-pole exposure as well as enclosure shape. For the 15-layer hemi-spheroid, the restart-critical compartment minimum varies by less than 1 K across the sampled 12:00–16:00 lunar local solar time (LLST) interval, with fixed component initial temperatures across deployment cases. Here, 24 LLST hours span one lunar solar day. At the next sampled deployment time, 18:00 LLST, the minimum falls below −40 °C. The selected baseline—hemi-spheroid, 15 MLI layers, 0.850 kg accounted concept-level mass excluding additional deployment and integration hardware—reaches a best sampled minimum of −38.05 °C. This meets a fallback battery storage-temperature criterion of −40 °C, but not the primary criterion of −20 °C for the selected commercial off-the-shelf (COTS) cell; it does not establish post-night restart capability. Two options warrant further assessment: substitution of a cold-rated cell, reducing specific energy from 248 to 207 Wh kg⁻¹, or active heating of the COTS cell. A preliminary ideal heating-energy estimate is approximately 38.6 kJ over the remainder of the night, equivalent to 7.3% of nominal battery energy, before accounting for system losses and reduced usable capacity at low temperature.
Key assumptions include nominal MLI effective emissivity, an idealised skirt-to-regolith interface and prescribed initial temperatures. Numerical verification, shelter-level experimental validation and battery restart qualification remain future work.