For a moment Lieutenant Swenson seemed to have run out of steam as his big chest gasped for breath. Clay was so overcome he stood with lips trembling and eyes smarting. Rob suspected this was perhaps the first real dressing-down he had had in his life, something that probably his own father had never done. Clay Gerard said nothing in defense. Lieutenant Swenson turned to Rob. “I’m sorry Rob, but I couldn’t help it. When I heard him blast out at you—” Rob remained silent and Lieutenant Swenson walked off with some embarrassment. Just then the rocket fighter angled up and sent Rob and Clay rolling over against the wall of the corridor. Clay’s head thumped against the metal, and the blow appeared to daze him. Rob helped him up as the ship continued to rock. “Are you hurt?” Rob asked him. Clay shook his head vigorously. “I—I don’t think so.” Rob hastened to the engine room, some impulse telling him that the misbehaving rocket chamber might be behind the trouble. He found Mort in front of an opening in the floor, a frantic look on his face. “The rocket cylinder that was heating up has blown a leak!” he shouted above a deafening swooshing sound from below. “Can you repair it?” Rob asked. “The ship is practically out of control!” “Tell Lieutenant Fox to cut all jets and keep her even,” the mechanic said. “I’ll have to go down into the hold to plug the break-through so it’ll last until we reach Titan.” Rob leaned over the hold and felt hot air rushing up at him. It was dark and crowded with machinery down there. “I don’t see how you can work down there in all that heat.” Mort shrugged. “I’ll have to, or we may never land. If I’d checked it when I had that tangle with Cadet Gerard I might have saved the blowout.” Rob sensed someone behind him and turned to see Clay, who had followed him into the engine room. Rob saw a stark look on the cadet’s face as though the grave significance of his clash with Mort were suddenly made startlingly real to him. “Can I help?” Clay asked. “If you can, we’ll let you know,” Rob told him as he hurried from the room toward the pilot’s nest forward. After instructing Lieutenant Fox, Rob returned to the engine room. As though anxious to make himself useful, Clay was leaning over the hold into which Mort had disappeared, pointing a flashlight for him. The other crewmen, except for the pilot, were gathered around in a tense knot. By now, the ship had leveled off somewhat and the unevenness was less severe. “How is Mort coming?” Rob asked them. “He’s complaining of the heat, sir,” Harry said. “He’s liable to collapse down there.” Rob leaned over the hold. “How are you, Mort?” “I’m nearly through!” came a feeble reply. “He sounds weak,” Lieutenant Swenson said. “I wish one of us knew how to repair the damage,” Rob said. “We could give him relief.” He turned to Clay. “Let me have the light.”