The Margin The habitat ring of Vanguard turned once every 42 seconds. At 8.2 rpm the spin gave 0.38 g at the outer deck—enough to keep bones from dissolving, enough to let people walk instead of float, enough to make coffee…

The Regolith House In 2053 the first permanent lunar settlement was not a dome or a lava-tube city. It was six buried habitats on the rim of Shackleton Crater at the lunar south pole. Each habitat was a 12-meter-diameter cylindrical pressure…

The Twenty-Kilometer Eye In 2039 the skies above 18 km altitude became sovereign territory. The Outer Space Treaty of 1967 never defined where airspace ended and outer space began. The Karman line (100 km) was an engineering convenience, not law. By…