He puffed with the effort. Each step was agony. The tendons of his knees were cracking, and there were knives in his side.
Mullen stopped to let the perspiration dry. It wouldn't do to steam up the inside of his faceplate. He flashed his wrist-lights, and the steam-cylinder was right ahead.
The ship had four of them, at ninety degree intervals, thrusting out at an angle from the midgirdle. They were the "fine adjustment" of the ship's course. The coarse adjustment was the powerful thrusters back and front which fixed final velocity by their accelerative and the decelerative force, and the hyperatomics that took care of the space-swallowing Jumps.
But occasionally the direction of flight had to be adjusted slightly and then the steam-cylinders took over. Singly, they could drive the ship up, down, right, left. By twos, in appropriate ratios of thrust, the ship could be turned in any desired direction.
The device had been unimproved in centuries, being too simple to improve. The atomic pile heated the water content of a closed container into steam, driving it, in less than a second, up to temperatures where it would have broken down into a mixture of hydrogen and oxygen, and then into a mixture of electrons and ions. Perhaps the breakdown actually took place. No one ever bothered testing; it worked, so there was no need to.
At the critical point, a needle valve gave way and the steam thrust madly out in a short but incredible blast. And the ship, inevitably and majestically, moved in the opposite direction, veering about its own center of gravity. When the degrees of turn were sufficient, an equal and opposite blast would take place and the turning would be canceled. The ship would be moving at its original velocity, but in a new direction.
Mullen had dragged himself out to the lip of the steam-cylinder. He had a picture of himself-a small speck teetering at the extreme end of a structure thrusting out of an ovoid that was tearing through space at ten thousand miles an hour.
But there was no air-stream to whip him off the hull, and his magnetic soles held him more firmly than he liked.
With lights on, he bent down to peer into the tube and the ship dropped down precipitously as his orientation changed. He reached out to steady himself, but he was not falling. There was no up or down in space except for what his confused mind chose to consider up or down.
The cylinder was just large enough to hold a man, so that it might be entered for repair purposes. His light caught the rungs almost directly opposite his position at the lip. He puffed a sigh of relief with what breath he could muster. Some ships didn't have ladders.
He made his way to it, the ship appearing to slip and twist beneath him as he moved. He lifted an arm over the lip of the tube, feeling for the rung, loosened each foot, and drew himself within.
The knot in his stomach that had been there from the first was a convulsed agony now. If they should choose to manipulate the ship, if the steam should whistle out now- He would never hear it; never know it. One instant he would be holding a rung, feeling slowly for the next with a groping arm. The next moment he would be alone in space, the ship a dark, dark nothingness lost forever among the stars. There would be, perhaps, a brief glory of swirling ice crystals drifting with him, shining in his wrist-lights and slowly approaching and rotating about him, attracted by his mass like infinitesimal planets to an absurdly tiny Sun.
He was trickling sweat again, and now he was also conscious of thirst. He put it out of his mind. There would be no drinking until he was out of his suit-if ever.
Up a rung; up another; and another. How many were there? His hand slipped and he stared in disbelief at the glitter that showed under his light.
Ice?
Why not? The steam, incredibly hot as it was, would strike metal that was at nearly absolute zero. In the few split-seconds of thrust, there would not be time for the metal to warm above the freezing point of water. A sheet of ice would condense that would sublime slowly into the vacuum. It was the speed of all that happened that prevented the fusion of the tubes and of the original water-container itself.
His groping hand reached the end. Again the wrist-lights. He stared with crawling horror at the steam nozzle, half an inch in diameter. It looked dead, harmless. But it always would, right up to the micro-second before- Around it was the outer steam lock. It pivoted on a central hub that was springed on the portion toward space, screwed on the part toward the ship. The springs allowed it to give under the first wild thrust of steam pressure before the ship's mighty inertia could be overcome. The steam was bled into the inner chamber, breaking the force of the thrust, leaving the total energy unchanged, but spreading it over time so that the hull itself was in that much less danger of being staved in.
Mullen braced himself firmly against a rung and pressed against the outer lock so that it gave a little. It was stiff, but it didn't have to give much, just enough to catch on the screw. He felt it catch.
He strained against it and turned it, feeling his body twist in the opposite direction. It held tight, the screw taking up the strain as he carefully adjusted the small control switch that allowed the springs to fall free. How well he remembered the books he had read!
He was in the interlock space now, which was large enough to hold a man comfortably, again for convenience in repairs. He could no longer be blown away from the ship. If the steam blast were turned on now, it would merely drive him against the inner lock-hard enough to crush him to a pulp. A quick death he would never feel, at least.
Slowly, he unhooked his spare oxygen cylinder. There was only an inner lock between himself and the control room now. This lock opened outward into space so that the steam blast could only close it tighter, rather than blow it open. And it fitted tightly and smoothly. There was absolutely no way to open it from without.
He lifted himself above the lock, forcing his bent back against the inner surface of the interlock area. It made breathing difficult. The spare oxygen cylinder dangled at a queer angle. He held its metal-mesh hose and straightened it, forcing it against the inner lock so that vibration thudded. Again- again- It would have to attract the attention of the Kloros. They would have to investigate.
He would have no way of telling when they were about to do so. Ordinarily, they would first let air into the interlock to force the outer lock shut.
But now the outer lock was on the central screw, well away from its rim. Air would suck about it ineffectually, dragging out into space.
Mullen kept on thumping. Would the Kloros look at the air-gauge, note that it scarcely lifted from zero, or would they take its proper working for granted?
Porter said, "He's been gone an hour and a half."
"I know," said Stuart.
They were all restless, jumpy, but the tension among themselves had disappeared. It was as though all the threads of emotion extended to the hull of the ship.
Porter was bothered. His philosophy of life had always been simple-take care of yourself because no one will take care of you for you. It upset him to see it shaken.
He said, "Do you suppose they've caught him?"
"If they had, we'd hear about it," replied Stuart, briefly.
Porter felt, with a miserable twinge, that there was little interest on the part of the others in speaking to him. He could understand it; he had not exactly earned their respect. For the moment, a torrent of self-excuse poured through his mind. The others had been frightened, too. A man had a right to be afraid. No one likes to die. At least, he hadn't broken like Aristides Polyorketes. He hadn't wept like Leblanc. He- But there was Mullen, out there on the hull.
"Listen," he cried, "why did he do it?" They turned to look at him, not understanding, but Porter didn't care. It bothered him to the point where it had to come out. "I want to know why Mullen is risking his life."