In the lobby of Interlune, a 3-foot-wide tabletop diorama shows an idyllic, toy-size version of the mining operation the Seattle startup wants to build on the #moon. Boxy autonomous vehicles scrape up the top layer of lunar dirt and crush it to release gas containing a valuable form of #helium. Solar panels on wheeled platforms generate power. Off to one side, a box resembling a military missile launcher is loaded with small rockets designed to carry bottles of the gas back to Earth. What #Interlune is trying to do is far from child’s play. Helium-3, an industrially prized cousin of the isotope of the gas we use to fill party balloons, is rare on Earth. In 2024 it sold for $2,500 per liter, or roughly $19 million a kilogram, according to a report from Edelgas Group. Interlune CEO Rob Meyerson expects an installation with just five of his #mining machines could one day produce at least 10 kg of helium-3 a year, worth close to $200 million. The company faces daunting hurdles to get the...