Space Is an Untapped Resource 11 specialty fiber optic cables, specialty glass such as sapphire glass, and metal crystals (such as for jet engine blades). In extracting oxygen from the metal oxides in the regolith, metals are readily available as a by-product it will be possible to use the oxygen, metals, and slag to build out the habitat and Lunar industrial facility to enable greater scale production. It is then possible to mine structural materials, like aluminum and iron to build spacecraft and structures, and high-tech parts for use on Earth, such as jet engine blades or superhard aircraft canopies. In the process, vacuum and low-gravity processes will enable extreme purity for applications like the manufacture of lithium batteries. Along the way, while materials are being separated, it will likely be possible to find high concentrations of platinum group metals (PGMs), which are critical minerals for the green economy and integrated circuits and are strategic minerals for national defense. PGMs may be valuable enough to ship to Earth. According to a report from Citigroup, “[F]or transporting to Earth, heat shielded capsules filled with gas bubbles could also be used and simply dropped into the oceans for ships to tow them away.”51 And as mentioned earlier, space-mined materials are desirable for the prized rare materials themselves. Aside from PGMs essential for high-tech devices, fuel cells, and the hydrogen economy, one of the most valued commodities may be helium-3 (He-3)—a rare isotope in the solar wind that embeds itself in the Lunar dust deflected by Earth’s magnetic field. When humanity finally succeeds in sustained fusion, He-3 will be a highly desirable fuel both for fusion power on Earth and for fusion power and propulsion in space because it produces very few neutrons, which are harmful to humans and damage reactors. Approximately 25 tons of He-3 (which would fit in the space shuttle’s cargo bay) has enough energy to power the entire United States for a year and, therefore, is worth about $3 billion per ton.52 In addition to America, both China and India, with vast populations to sustain, have an interest in this potential clean energy fuel. Finally, the largest market and use for space mining will likely be entirely new industries built in space.53 These may include construction of very large satellites, large space stations, factories, server farms, and power sta- tions. For example, global energy needs are forecast to grow from 31 ter- awatts (TW) to 55 TW by 2100.54 A single solar power satellite (discussed below) might have a mass of 10,000 metric tons, and more than 90 percent of the materials required for its construction (silicon, aluminum, iron) are available on the Moon. With today’s launch economics, less than 4 per- cent of a rocket from Earth can be cargo.55 However, with significantly less gravity to overcome, a launch from the Moon can carry 50 percent cargo— with zero impact to the Moon’s biosphere, though it will be important to ensure the foreign environment is not damaged by mining and launches as well.56 Eventually, because the Moon has no atmosphere, an electric catapult may be more economical than a rocket.