Insulation Stack Shields

Radiation Shield Layers no.

Shield Emissivity ε

Aluminised film runs 0.02 to 0.05 when clean.

Suit Surface Area m²

Environment & Crew Boundary conditions

Sunlit Outer Temperature °C

Inner Boundary Temperature °C

Metabolic & Equipment Load W

Heat Leak Through Insulation

— W

Radiative transfer across the whole shield stack

Thermal Performance

Radiative Flux: — W/m²
Effective Emittance: — ε
Effective Conductance: — W/m²K
Equivalent Resistance: — m²K/W
Total Cooling Load: — W

Ideal MLI is what this models, and real MLI never achieves it. Seams, edges, penetrations and the spacer material between shields all conduct, and that parasitic path routinely dominates the radiative leak computed here — measured blanket performance is commonly several times worse than the layer count suggests. Compression destroys the blanket outright by putting shields in contact, which is why joints and anywhere the suit bends perform far below a flat panel. Residual gas conduction also returns as soon as the vacuum is imperfect. Real suits carry a whole-suit thermal balance and an active cooling garment, both outside this calculation.

Space Suit Multi-Layer Insulation Thermal Gradient — free, with the formula and a worked example, at Textile School.