The procedure was repeated over and over. Below them, on the cold dead surface of the moon, carefully plotted explosions cut a swath of destruction that could destroy any man-made structure ever raised. Space torpedoes were slow, easy to dodge or hit with a ray beam. They had been abandoned in modern combat. But they were the most powerful explosive force ever created by human science. In the control room there was nothing to hint at success, or failure. But McPartland knew the torpedoes couldn't be seen or destroyed with ray beams in this etherless black. Nothing could halt the methodical blasting. Jon grinned. The super-science of the plotters made it possible to use an obsolete weapon against them. "What if some miss the edge?" asked Clemens anxiously. The _Avenger_ was running around the circumference of the satellite, following a course that drew ever-tighter circles until the last torpedo was delivered in the exact center. "The fuse is set to explode them before they reach the Earth," McPartland told him. "But none will miss." There was silence then in the room, except for the unending duet of Parek and McTavish, coming sharp and clear through the ship phone. The three officers braced their legs hard against the deck, as the ship raced at maximum speed into sharper turns. In the end, the _Avenger_ seemed to whip around almost in its own length. Jon balanced himself with effort, his stomach rising within him. He was giddy and nauseated. His eyes strained for something to focus on, to give him perspective. There was nothing. He was still blind. * * * * * "We blasted every foot on that side of the moon," McPartland said bitterly, "but we didn't get the machinery." "No, man," agreed McTavish who had come up to the control room again. "That cursed devil's mantle is still there!" The Captain's blue eyes burned into the forward screen. "They're waiting on Terra Base, too," he grated. "But we'd see the break first. The light would come back at the edges, and--" he stumbled over the implication of the next words, "work-in-toward-the-center!" McTavish's grey eyes blazed suddenly. "In toward the center, man! Right! But the moon isn't at the center!" Jon was already shouting into the phone: "Observation Officer. Locate the exact center of that area, in relation to this ship, Terra, and Luna. "Navigation! Get bearings from Observation, and plot torpedo course for dead center." "This will do it, Sir," shouted the Engineer. "I should have thought of it, Sir, begging your pardon." "It may be well protected, Sir," Clemens suggested. Clemens quietly relayed the report from Observation: "Impossible to locate exact center, Sir. Whole area is shifting constantly, unpredictably." He shot a look of glum satisfaction at McTavish, and added: "The approximate center is on the far side of Terra and Luna, Sir."