His ventilator had quieted down once he got into the darkness, but now it started whining slightly again because he was sweating profusely. Finally he figured out the thrust needed to stop the spin. Now all he had to do was compute how much fuel it would take. He had figures on the amount of thrust given by the kind of rocket fuel in the tubes. He also knew how much fuel each tube contained. But the figures were not in his head. They were on reference sheets. He collected the data on the fly, slowing down now and then to read something, until a yell from Santos or Koa warned that the sun line was creeping close. When he had all data noted on the board, he started his mathematics. He was right in the middle of a laborious equation when he stumbled over a thorium crystal. He went headlong, shooting like a rocket three feet above the ground. His board flew away at a tangent. His stylus sped out of his glove like a miniature projectile, and the slide rule clanged against his bubble. It happened so fast that neither Koa nor Santos had time to grab him. The action had given him extra speed, and he saw with horror that he was going to crash into Trudeau. He yelled, "Frenchy! Watch out!" Then he put both hands before him to protect his helmet. His hands caught the French Planeteer between the shoulders. CHAPTER SEVENTEEN Visitors! Trudeau held tight to the launcher, but the rocket racks opened and spilled attack rockets into space. They flew in a dozen different directions. Trudeau gave vent to his feelings in colorful French. Koa and Santos laughed so hard they had trouble collecting the scattered equipment. Rip, slowed by his crash with Trudeau, got his feet under him again. When the asteroid turned into the sun, they still had not collected Rip's stylus and five of the attack rockets. The space pencil was the only thing that could write on the computing board. It had to be found. "Next time around," Rip called to the others. He then led the way full speed ahead until they reached the safety of shadow again. Rip suspected the stylus was somewhere above the rock and probably wouldn't return to the surface for some minutes. While he was wondering what to do, there was a chorus of yells. A rocket sped between the Planeteers and shot off into space. "Our own rockets are after us," Trudeau gasped. There hadn't been time to collect them all after Rip's unwilling attack on the Frenchman had scattered them. Now the sun was setting them off. Another flashed past, fortunately over their heads. The sun's heat was causing them to fire unevenly. "Three more to go," Koa called. "Watch out!" Only two went, and they were far enough away to offer no danger. Santos had been fishing around in the instrument case. Suddenly he produced another stylus. "It was under the sextant," he explained triumphantly.