Like all spaceships, "Nomad" was ballasted and stiffened with the mass of her gas tanks laid down the length of her keel like a long lumber raft tapped at the sides by a labyrinth of pipe fittings. Foyle took a minute disconnecting an air tank. He had no way of knowing whether it was full or already exhausted; whether he would fight it back to his locker only to discover that it was empty and his life was ended. Once a week he endured this game of space roulette.