The financial, environmental, and national security carrot for helium-3 fusion power requires access to low-cost lunar helium-3. Helium-3 fusion potentially would provide an environmentally benign means of helping to meet an anticipated ninefold or increase in energy demand by 2050. Not available in other than research quantities on Earth, this light isotope of ordinary helium-4 reaches the Moon as a component of the solar wind. Embedded continuously in the lunar dust for billions of years, concentrations have reached levels of potential economic interest. Near the United States Apollo 11 landing site in Mare Tranquillitatis, 2 km² (0.8 mi²), to a depth of 3 m (9.8 ft), contains about 100 kg (220 lb) of helium-3, that is, more than enough to power a 1000 MWe (1 gigawatt [GW]) fusion power plant for a year.

In 2008, the energy equivalent value of helium-3 relative to $2.50/million Btu (0.25 10⁶ kcal) industrial coal equaled about US $1.4 billion a metric tonne (1.1 tons). One metric tonne (1.1 tons) of helium-3, fused with deuterium, a heavy isotope of hydrogen, has enough energy to supply a city of 10 million with a year's worth of electricity or more than 10 GW of power for that year.

The financial envelope within which helium-3 fusion must fit to be of interest to potential investors, as related to other 21st century energy sources, includes total development cost approximately US $15 billion, competitive coal costs US $2.50 or higher/million Btu (0.25 10⁶ kcal), and payload costs to the Moon approximately US $3000/kg ($1360/lb).