Solar-wind-implanted helium-3 sits in the outer skin of every regolith grain. Getting it out is a mass-balance problem, not a driving animation: how much gas is in the soil you dig, how much of that gas a given temperature actually releases, and whether you have the power to heat regolith that fast.
avgConc(d) = C0 · (Ls/d) · (1 − e^(−d/Ls)) [depth-averaged ppb]
eff(T) = 1 / (1 + e^(−(T−500)/70)) [thermal release, 0–1]
Emax(T) = P_solar · sin(elevation) [available power, W]
q_max = Emax / (cp·(T−T_amb)) [power-limited mass rate, kg/s]
q = min(q_target, q_max) [actual regolith rate]
Y_He3 = q · avgConc(d)·1e-9 · eff(T) [He-3 mass rate, kg/s]
Concentration falls off with depth because only the top layer has had enough solar-wind exposure time to accumulate gas — dig deeper and you dilute the yield with older, gas-poor material. Extraction efficiency follows a sigmoid centered near 500°C, matching how implanted noble gases desorb from lunar ilmenite/glass over a narrow thermal window. Available power scales with sun elevation (the panels are always tracked to the sun), and heating regolith to a higher temperature costs more energy per kilogram — so above a certain throughput the process goes power-limited and the actual mass rate falls below the target you set, which the power readout box turns amber to flag.
- Depth — trade concentration for volume; shallow digging is richer per kilogram.
- Temperature — trade efficiency for energy cost; too hot and low power throttles you back.
- Throughput — the target mining rate; only achieved when power allows it.
- Sun elevation — sets the power ceiling for everything else.