The He-3 concentration on Luna is small, only a few parts per billion. It requires 500,000 tons of raw material (an area of about 1,000 square yards to the depth of four inches) to produce one pound of He-3. Lunar processing plants use automated machinery: robot bulldozers to scoop up the regolith, ovens to bake the soil to 1,300F, conveyors, and waste processing plants. This is a huge amount of effort, only justified by the worth of each pound of He-3, which can generate staggering amounts of energy when fused with deuterium. With all the other costs of operating a lunar mining base, the profits are not huge. However, a side effect of the processing is that it also yields economically useful quantities of elements such as oxygen and hydrogen, which support other Luna colony projects.

Extracting He-3 from Saturn (and potentially, from other gas giants) is cheaper, as it can be scooped directly out of the atmosphere. Specially designed drone scoop craft dive into the atmosphere and use high-thrust fission rockets to lift gas out to orbiting refineries. The gas is refined into He-3, then shipped via fusion-powered tanker to Earth or elsewhere. A few thousand tons are used annually (a tanker every few months), but demand is expected to double every 15-20 years. Even so, there's enough He-3 in Saturn alone to last centuries, and more in the other gas giants.