Seen on a video window in the display above, the hanger’s tailgate dilated, showing a disk of black sky. A tattoo of metallic clunks let them know that the brakes on the sled had been released. Driven down the ramp by centripetal force, it built speed all the way to the lip of the hanger deck and then stopped short with a sneeze from its shock absorbers. The flivver jerked free of the sled. From its occupants’ point of view, it seemed to fall off the edge of the deck and into space. En route it picked up a bit of a tumble, which was killed by quick firings of its thrusters.