The Shipyard had been stocked with several cryogenic propellant tanks of various sizes, some designed to hold LH2 (liquid hydrogen) and others built to the somewhat different specifications needed in the case of LOX (liquid oxygen). The chosen tanks were bolted together in a stack with the rocket engine mounted "below" and thermal protection wrapped all about. New Caird proper—the arklet with the humans in it—projected forward on a scrap of scaffolding just long enough that her maneuvering thrusters wouldn’t damage any of the other parts when they came on.