Bigman said, "Suppose you come back with more energy than you had when you left? How would that be?"

"Super-superlative, Bigman, but impossible. There's something called the second law of thermodynamics that stands in the way of making a profit on the deal or, for that matter, of breaking even. We've got to take some loss." He smiled broadly and said, "One minute."

And at the appropriate second the sound of the hyperatomics filled the ship with its muted murmurings, and Panner placed his watch in his pocket with a satisfied expression.

"From here on in," he said, "until actual landing maneuvers at the Jupiter Nine approach, everything is quite automatic."

He had no sooner said that when the humming ceased again, the lights in the room flickered and went out. Almost at once they went on again, but now there was a little red sign on the control panel that said, emergency.

Panner sprang to his feet. "What in Space…?''

He left the pilot room at a run, leaving the others staring after him and at one another in various degrees of horror. The commander had gone dead-white, Ms lined face a tired mask.

Lucky, with sudden decision, followed Panner, and Bigman, of course, followed Lucky.

They came upon one of the engineers clambering out of the engine compartment. He was panting. "Sir!"

"What is it, man?" snapped Panner. "The Agrav is off, sir. It can't be activated."

"What about the hyperatomics?"

"The main reserve is shorted. We cut it just in time to keep it from blowing. If we touch it, the whole ship will go up. Every bit of the stored energy will blow."

''Then we're working on the emergency reservoir?"

''That's right."

Panner's swarthy face was congested with blood. "What good is that? We can't set up an orbit about Jupiter with the emergency reservoir. Out of the way. Let me down there."

The engineer stepped aside, and Panner swung into the shaft. Lucky and Bigman were at his heels.

Lucky and Bigman had not been in the engine compartment since that first day aboard the Jovian Moon. The scene was different now. There was no august silence, no sensation of mighty forces quietly at work.

Instead, the puny sound of men rose high about them.

Panner sprang off into the third level. "Now what's wrong?" he called. "Exactly what's wrong?"

Men parted to let him through and they all huddled over the gutted insides of a complex mechanism, pointing things out in tones of mingled despair and anger.

There were sounds of other footsteps coming down the rungs of the shaft, and then the Commander himself made his appearance.

He spoke to Lucky, who was standing gravely to one side. "What is it, Councilman?" It was the first time he had addressed Lucky since they had left Jupiter Nine.

Lucky said, "Serious damage of some sort, Commander."

"How did it happen? Panner!"

Panner looked up from the close examination of something that had been held out to him. He shouted in annoyance, "What in space do you want?"

Commander Donahue's nostrils flared. "Why has something been allowed to go wrong?"

"Nothing has been allowed to go wrong."

"Then what do you call this?"

"Sabotage, Commander. Deliberate, murdering sabotage!"

"What!"

"Five gravitic relays have been completely smashed and the necessary replacements have been removed and can't be located. The hyperatomic thrust-control has been fused and shorted beyond repair. None of it happened by accident."

The commander stared at his chief engineer. He said, hollowly, "Can anything be done?"

"Maybe the five relay replacements can be located or cannibalized out of the rest of the ship. I'm not sure. Maybe a makeshift thrust-control can be set up. It would take days anyway and I couldn't guarantee results."

"Days!" cried the commander. "It can't take days. We're fatting toward Jupiter!"

There was a complete silence for a few moments, and then Panner put into words what all of them knew. "That's right, Commander. We're failing toward Jupiter and we can't stop ourselves in time. It means we're through, Commander. We're all dead men!"

It was Lucky who broke the deadly silence that followed, in sharp, incisive tones. "No man is dead while he has a mind capable of thought. Who can handle this ship's computer most rapidly?"

Commander Donahue said, "Major Brant. He's the regular trajectory man."

"Is he up in the control room?"

"Yes."

"Let's get to him. I want the detailed Planetary Ephemerae … Panner, you stay here with the men and get to work cannibalizing and improvising."

"What good will it-?" Panner began.

Lucky cut in at once. "Perhaps no good at all. If so, we'll hit Jupiter and you'll die after having wasted a few hours of labor. Now I've given you an order. Get to work!"

"But…" Commander Donahue seemed stuck after that one word.

Lucky said, "As councilman of science, I'm assuming command of this vessel. If you wish to dispute that, I'll have Bigman lock you in your cabin and you can argue it out at the court-martial proceedings, assuming we survive."

Lucky turned away and moved quickly up the central shaft. Bigman motioned Commander Donahue up with a quick jerk of his thumb and followed last.

Panner looked after them scowling, turned savagely to the engineers, and said, "All right, you bunch of corpses. No use waiting for it with our fingers in our mouths. Hop to it."

Lucky strode into the control room.

The officer at the controls said, "What's wrong down there?" His lips were white.

"You're Major Brant," said Lucky, "We haven't been formally introduced, but never mind that. I'm Councilman David Starr, and you're taking orders from me. Get at that computer and do what you're told with all the speed you have."

Lucky had the Planetary Ephemerae before him. Like all great reference works, it was in book form rather than film. The turning of pages, after all, made for the more rapid location of a specific piece of information, than did the long-drawn-out unwinding of film from end to end.

He turned the pages now with practiced hand, searching among the rows and columns of numbers that located the position of every chunk of matter in the solar system over ten miles in diameter (and some under) at certain standard tunes, together with their planes of revolution and velocity of motion.

Lucky said, "Take the following co-ordinates as I call them out, together with the line of motion, and calculate the characteristics of the orbit and the position of the point at this moment and for succeeding moments for the space of forty-eight hours."

The major's fingers flew as figures were converted by the special punch machine into a coded tape which was fed into the computer.

Even while that was taking place, Lucky said, "Calculate from our present position and velocity our orbit with respect to Jupiter and the point of intersection with the object whose orbit you have just calculated."

Again the major worked.

The computer spat out its results in coded tape that wound on to a spool and dictated the tapping of a typewriter that spelled out the results in figures.

Lucky said, "At the point of intersection, what is time discrepancy between our ship and the object?"

Again the major worked. He said, "We miss it by four hours, twenty-one minutes, and forty-four seconds."

"Calculate how the velocity of the ship must be altered in order to hit the point squarely. Use one hour from now as the starting time."

Commander Donahue broke in. "We can't do anything this close to Jupiter, Councilman. The emergency power won't break us away. Don't you understand that?"