"If we get through this, I'll propose you for ten more stripes," Rip vowed. "We'll make you the highest ranking sergeant that ever made a private's life miserable." Working slowly but more safely, Rip figured that slightly more than two and a half tubes would do the trick. Now to fire them. That meant finding a thorium crystal properly placed and big enough. There were plenty of crystals, so that was no problem. The next step was for Kemp to cut holes with his torch, so that the thrust of the rocket fuel would be counter to the direction in which the asteroid was spinning. Rip explained to all hands what had to be done. The burden would fall on Kemp, who would need a helper. Rip took that job himself. He took one oxygen tank from Kemp. Koa took the other, leaving the torchman with only his torch. Then Rip took a container of chemical fuel from Bradshaw. Working while running, he lashed the two containers together with his safety line. Then he improvised a rope sling so they could hang on his back. Kemp, meanwhile, assembled his torch and put the proper cutting nozzle in place. When he was ready, he moved over to Rip's side and connected the torch hoses to the tanks the lieutenant carried. Kemp had the torch mechanism strapped to his own back. It was essentially a high-pressure pump that drew oxygen and fuel from the tanks and forced them through the nozzle, under terrific pressure. When he had finished, he pressed the trigger that started the cutting torch going. The fuel ignited about a half inch in front of the nozzle. The nozzle had two holes in it, one for oxygen and the other for fuel. The holes were placed and angled to keep the flame always a half inch away, otherwise the nozzle itself would melt. "How do we work this?" Kemp asked. "We'll get ahead of the others," Rip explained. "Keep up speed until we're running at the forward sun line. Then, when the crystal we want comes around into the shadow, we stop running and work until it spins back into the sunshine again." Rip estimated the axis on which the asteroid was spinning and selected a crystal in the right position. He had to be careful, otherwise their counterblast might do nothing more than start the gray planet wobbling. He and Kemp ran ahead of the others. The Planeteers and their prisoners were running at a speed that kept them right in the middle of the dark area. It was like running on a treadmill. The Planeteers were making good speed, but were actually staying in the same place relative to the sun's position, keeping the turning asteroid between them and the sun.