ZION HAD BEEN founded by five workers who’d refused to return, who’d turned their backs on the well and started building. They’d suffered calcium loss and heart shrinkage before rotational gravity was established in the colony’s central torus. Seen from the bubble of the taxi, Zion’s makeshift hull reminded Case of the patchwork tenements of Istanbul, the irregular, discolored plates laser-scrawled with Rastafarian symbols and the initials of welders.