Dense white vapors poured over them from the generated heat as they fired upward into the jet cylinders. There were small, rocking explosions, and balls of fire burst before their eyes. Duff was knocked off his feet, and Rob and the officer were shaken. Duff rose again and valiantly went back to work with his companions. “We must have ignited small amounts of explosive gases in the atmosphere,” Lieutenant Stone said. The explosions began to be fewer, but the white vapors persisted. At last holes were opened in three of the large cylinders. Rob looked up, and presently space-suited figures appeared overhead in the opening he had blasted out. The men quickly hooked ladders, used for cleaning the jet chambers, over the side and started down—clumsily after the bitter ordeal they had gone through. Some were so overcome by the raw cold they could scarcely walk when they were outside. One of the research scientists complained mournfully about having to leave his equipment behind. Each man was assisted across the ice to the waiting space boats. Spacemaster Nielson, who appeared in somewhat better shape than most of his men, helped in this. “The engines have gone dead!” Duff noticed. “I sure hope we can get them started up again,” the lieutenant groaned, helping the last crewman he was to take into his rocket. Rob told Lieutenant Stone to go on, that he had only one more crewman to help out of the _Capella_. Lieutenant Stone got in, closed the door, and started up the stalled jets. They sputtered reluctantly, then began firing evenly. Rob was grateful to see the capsule shape lift safely into the sky a moment later. Rob and Duff returned to the doomed ship and motioned for the last crewman at the top of the rocket shaft to come down. The space-suited figure was about to start when he suddenly collapsed and fell over on the floor up above! “Give me a boost into the chamber,” Rob asked Duff. Duff assisted him, and he caught hold of the lower rung of the ladder and pulled himself inside. It was an exhausting climb up the ladder in his bulky suit, and for a moment or two he thought he could not make it except for the man’s pressing need. Finally he reached the floor level and leaned over the crewman who had collapsed. It was Jim Hawley, his face ashy gray with cold! Rob hastily propped him over his shoulders. In Pluto’s light gravity pull it was not too much of a load. Carefully Rob started down the ladder. The icy glaze that encrusted the metal rungs was treacherous. A fall might easily be fatal, for a torn suit would bring quick death from the temperature.