The Sweeper’s Orbit In 2097 the orbital graveyard above Earth was full. More than 36,000 tracked objects larger than 10 cm orbited between 300 and 2,000 km altitude—spent upper stages, defunct satellites, fragments from 2009 Iridium-Cosmos collision, 2007 Chinese ASAT test,…

The Long Sail The sailship Aurora Australis left Earth-Moon L2 in 2086. She carried no crew. Her payload was 1,200 tonnes of frozen embryos, oocytes, sperm, and somatic cell lines—enough genetic diversity for a viable colony of 10,000 individuals if revival…

The Shield Wall In 2091 the first permanent habitat at Sun-Earth L4 was not a gleaming city in space. It was a stack of six cylindrical pressure vessels, each 22 meters long and 8 meters in diameter, bolted end-to-end like a…