Lunar Helium-3 Thermal Extraction

Heating Cycle

Bake temperature 700 °C

Cycle duration 4 h

Regolith batch mass 1000 kg

Idle — set parameters and run a cycle.

Yield

Released fraction

0.0%

He-3 extracted

0 µg

Heating energy

0.00 kWh

Yield / energy

0.00 µg/kWh

Release time constant τ(T)

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How it works

Solar-wind protons and He-3 ions implant a few tens of nanometres into every regolith grain over the eons the surface sits exposed — real Apollo samples measure roughly 20 ppb He-3 by mass. Getting it back out means heating the grains until thermally-activated diffusion lets the trapped gas random-walk to the grain surface and escape. That diffusion follows the Arrhenius law:

τ(T) = τ₀ · exp(Eₐ / R·T)      [grain release time constant]
F(t)  = 1 − exp(−t / τ(T))     [fraction of trapped He-3 released]

with activation energy Eₐ ≈ 180 kJ/mol (representative of He-3 bound in ilmenite/glassy regolith), gas constant R = 8.314 J/(mol·K), and T in kelvin. Because Eₐ/R·T sits inside an exponential, τ swings by many orders of magnitude across the practical bake range — release is negligible below roughly 500 °C and becomes fast within hours above 700 °C, which is exactly the "knee" seen in real stepped-heating extraction experiments.

Bake temperature — sets τ(T); the grains glow brighter and the escaping-gas plume thickens as T rises.
Cycle duration — how long the batch bakes; F(t) is evaluated at t = duration.
Batch mass — total regolith processed; extracted mass = batch mass × 20 ppb × F(t).
Heating energy — Q = m·c·ΔT with regolith specific heat c ≈ 0.71 J/(g·K) and ΔT from a −20 °C lunar-day baseline to the bake temperature, converted to kWh.

The animated run compresses the real duration into a fixed 12-second playback so the escaping-gas rate — proportional to dF/dt — stays visible instead of finishing instantly or taking hours.

🌡 700 °C

Regolith grains Escaping He-3

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