Then there was a relative silence inside the ship. Only a faint mutter of voices came from assorted speakers that Keller had first turned on and then turned down, and a small humming sound from a gyro. When they listened, they could also hear a high sweet musical tone. Burke shifted this control here, and that control there, and lifted his hands. The ship moved on steadily. He checked this and that and the other thing. He was pleased. But there were innumerable things to be checked. Holmes went down the ladder to the other compartment below. There were details to be looked into there, too. One of the screens portrayed Earth from a height of seventy miles instead of eighty, now. Others pictured the heavens, with very many stars shining unwinkingly out of blackness. Keller got at his wires again and resumed the work of installing a ship-to-ground transmitter and its connection to an exterior-reflecting antenna. Sandy watched Burke as he moved about, testing one thing after another. From time to time he glanced at the screens which had to serve in the place of windows. Once he went back to the control-board and changed an adjustment. "We dropped down ten miles," he explained to Sandy. "And I suspect we're being trailed by jets down below." Holmes meticulously inspected all storage places. He'd packed them when the ship lay on her side. Burke read an instrument and said with satisfaction, "We're running on sunshine!" He meant that in empty space certain aluminum plates on the outside of the hull were picking up heat from the naked sun. The use of the drive-shaft lowered its temperature. Metallic connection with the outside plates conducted heat inward from those plates. The drive-shaft was cold to the touch, but it could drop four hundred degrees Fahrenheit before it ceased to operate as a drive. It was gratifying that it had cooled so little up to this moment. Later Keller tapped Burke on the shoulder and jerked his thumb upward. "We go up now?" asked Burke. Keller nodded. Burke carefully swung the ship to aim vertically. The views of solid Earth slid from previous screens to new ones. The stars and the dark object which was the sun also moved across their screens to vanish and reappear on others. Then Burke touched the drive-control. Once more they had the sensation of being in a rising elevator. And at just that moment spots appeared on the barren, icy, totally flattened terrain below. They were rocket-trails from target-seeking missiles which had reached the area of the north magnetic pole by herculean effort and were aimed at the radar-detected little ship by the heavy planes that carried them.