Feasibility of lunar Helium-3 mining

With fossil fuels running out and global energy demand increasing, the need for alternative energy sources is apparent. Nuclear fusion using Helium-3 may be a solution. Helium-3 is a rare isotope on Earth, but it is abundant on the Moon. Throughout the space community lunar Helium-3 is often cited as a major reason to return to the Moon. Despite the potential of lunar Helium-3 mining, little research has been conducted on a full end-to-end mission. This abstract presents the results of a feasibility study conducted by students from Delft University of Technology. The goal of the study was to assess whether a continuous end-to-end mission to mine Helium-3 on the Moon and return it to Earth is a viable option for the future energy market. The set requirements for the representative end-to-end mission were to provide 10% of the global energy demand in the year 2040. The mission elements have been selected with multiple trade-offs among both conservative and novel concepts. A mission architecture with multiple decoupled elements for each transportation segment (LEO, transfer, lunar surface) was found to be the best option. It was found that the most critical element is the lunar mining operation itself. To supply 10% of the global energy demand in 2040, 200 tons of Helium-3 would be required per year. The resulting regolith mining rate would be 630 tons per second, based on an optimistic concentration of 20 ppb Helium-3 in lunar regolith. Between 1,700 to 2,000 Helium-3 mining vehicles would be required, if using University of Wisconsin’s Mark III miner. The required heating power, if mining both day and night, would add up to 39 GW. The resulting power system mass for the lunar operations would be in the order of 60,000 to 200,000 tons. A fleet of three lunar ascent/descent vehicles and 22 continuous-thrust vehicles for orbit transfer would be required. The costs of the mission elements have been spread out over expected lifetimes. The resulting profits from Helium-3 fusion were calculated using a predicted minimum energy price in 2040 of 30.4 Euro/MWh. Annual costs are between 427.7 to 1,347.9 billion Euro, with annual expected profit ranging from -724.0 to 260.0 billion Euro. Due to the large scale of the mission, it has also been evaluated for providing 0.1% and 1% of the global energy demand in 2040. For 1%, the annual costs are 45.6 to 140.3 billion Euro and the expected annual profits are -78.0 to 23.1 billion Euro. For 0.1%, the annual costs are 7.7 to 20.5 billion Euro. The annual expected profits are -14.3 to -0.8 billion Euro. Feasibility has been addressed in three aspects. Technically, the mission is extremely challenging and complex. However, most required technologies exist or could be developed within a reasonable time span. From a political and legal perspective, the current international treaties hardly provide any framework for a lunar mining operation. Financially, the mission only produces a net profit in the best case, and only for medium- to large-scale operations, which require a very large initial investment. To make lunar Helium-3 usage possible, further research should concentrate on the mining operation and costs of fusion plants, as their impact by far outranks all other mission elements. Different transportation concepts may be investigated nevertheless. Many - not only technical - challenges concerning Helium-3 mining are still to be addressed. Although only a starting point for further investigations, this study shows that, despite popular claims, lunar Helium-3 is unsuitable to provide a significant percentage of the global energy demand in 2040.