But the total noise was not lessened. Another pushpot came soaring wildly into view, making hysterical outcries. It touched and banged violently to earth. Others appeared in the air beyond the construction Shed. One flopped so hard on landing that its tail rose in the air and it attempted a somersault. It made ten times more noise than before--the flame from its tail making wild gyrations--and flopped back again with a crash. Two others rolled over on their sides after touching ground. One ended up on its back like a tumble-bug, wriggling. They seemed to land by hundreds, but their number was actually in dozens. It was not until the last one was down that Joe could make himself heard. The pushpots were jet motors in frames and metal skin, with built-in jato rocket tubes besides their engines. On the ground they were quite helpless. In the air they were unbelievably clumsy. They were actually balanced and steered by vanes in the blasts of their jets, and they combined the absolute maximum of sheer thrust with the irreducible minimum of flyability. Crane-trucks went out to pick them up. Joe said anxiously, "We'd better check our flight plan again. We have to know it absolutely!" He headed across the floor to the flight data board. He passed the hull of another ship like his own, which was near completion, and the bare skeletons of two others which needed a lot of work yet. They'd been begun at distant plants and then hauled here on monstrous trailers for completion. The wooden mockup of the design for all the ships--in which every possible arrangement of instruments and machinery had been tested out--lay neglected by the Shed wall. The four stood before the flight data board. It listed the readings every instrument should show during every instant of the flight. The readings had been calculated with infinite care, and Joe and the others needed to know them rather better than they knew their multiplication tables. Once they started out, they wouldn't have time to wonder if everything was right for the time and place. They needed to know. They stood there, soaking up the information the board contained, forming mental pictures of it, making as sure as possible that any one of them would spot anything wrong the instant it showed up, and would instantly know what had to be done about it. A gigantic crane-truck came in through the wide doorway. It dangled a pushpot. It rolled over to the launching cage in which the spaceship lay and set the unwieldy metal object against that cage. There was a _clank_ as the pushpot caught hold of the magnetic grapples. The crane went out again, passing a second crane carrying a second pushpot. The second beetle-like thing was presented to the cage. It stuck fast. The crane went out for more.