"It will take weeks to repair it!"

Professor Hemmingwell stood on the main deck of the giant spaceship staring sadly at the mess of wires and tubes, controls and gauges, switches and filaments, all shattered and useless.

"When did it happen?" demanded Connel.

"Less than half an hour ago," replied Dave Barret. "Professor Hemmingwell and I were down at the far end of the hangar. The men had just left for the day and we were planning the work for tomorrow."

"Then what happened?" demanded Connel. "Wait, don't answer yet!" He stopped himself and turned to a Space Marine standing nearby. "You! Can you work an audio recorder?"

"Yes, sir," replied the Marine.

"Then get a machine up here on the double and take down everything that's said."

"Yes, sir," said the Marine and left the ship. Connel silently began inspecting the wreckage. It was ten times as serious as the first sabotage attempt.

Barret, Commander Walters, Professor Hemmingwell, and Captain Strong watched the major, their teeth clenched, eyes clouded with anger. Where the destruction of the first unit could have been called an accident, here was tangible evidence of a deliberate attempt to stop the whole project. The Space Marine, accompanied by Firehouse Tim Rush, returned five minutes later with the audio recorder and set it up for operation.

Connel took the small needlelike microphone in his hand and spoke into it as the reel of sound tape unwound slowly.

"This is a preliminary inquiry into the sabotage of the control deck of spaceship XX, Operation Space Projectile," he said. "This is Major Lou Connel, interrogator!" He paused and nodded to Barret who stepped forward. "My first witness will be Dave Barret." Holding the microphone close to the young engineer's mouth, Connel said, "Tell us everything you know of this incident."

Barret spoke slowly and carefully, describing how he and Professor Hemmingwell had been at the other end of the hangar when the explosion had occurred. Professor Hemmingwell had immediately run out of the hangar to inform Commander Walters, leaving Barret alone to check the damage. "Then you and Commander Walters and the Space Marines showed up, sir," he concluded. "That's all I know."

"All right," said Connel and turned to the professor. "Your statement, Professor Hemmingwell."

"It happened just about the way Dave said," Hemmingwell began. "Except for one thing. I cannot see why there weren't any guards at their posts this afternoon. We were without any men at the entrances for nearly an hour. Anyone could have slipped into the hangar and planted the bomb."

"Why weren't the entrances guarded?" snapped Connel, looking directly at Firehouse Tim Rush.

"Cadets Manning and Astro left their posts without leave, sir," reported the stocky little spaceman.

Captain Strong took an involuntary step forward, his face drained of all color. Connel looked at him, steely-eyed. "Did you hear that, Strong?" he growled.

Strong nodded. "I—I did," he stammered.

"So those two idiots not only stole a rocket scout, but they left their posts."

Strong could only shake his head in utter disbelief. Commander Walters looked at him pityingly.

"I knew they had taken the scout," said Walters, his voice hard and tight. "But I didn't think they were foolish enough to leave their posts."

"Well, they did, sir," declared Rush. "They left about four hours before they were to be relieved. I was making the rounds when I discovered that they were gone. I put two other men on guard right away, but the doors were unguarded for at least an hour. Anyone could have walked in without the slightest trouble."

Connel turned back to Walters. "This is the end! Those two cadets are going up before a general court-martial."

"Commander," protested Strong, "you can't—!"

"Shut up, Steve!" barked Connel. "There's a limit to how long you can defend your unit. Face it, man, those three boys have gone off their rockers. They're too cocky. This is the last straw." He turned away from the young Solar Guard officer and faced the others. "Let's get on with the interrogation. Firehouse! What have you got to say about this?"

The tough little enlisted guard stepped up and reported clearly and rapidly and without pause. When he was finished, Connel turned to the guards that had replaced Roger and Astro and each one repeated the story told by Firehouse Tim.

Over and over, Connel heard the same story. No one seemed to have been around the ship when the explosion took place. And it seemed that the only time when a saboteur could have gotten into the hangar and planted the bomb was during the hour the doors were unguarded.

Finally, the interrogation was over and Connel declared, "One thing to remember when you are dealing with sabotage is this: if the saboteur fails, he might return. If our enemy does not know the extent of the damage, then he might return and make another attempt. So, not a word about this to anyone. And that includes your mothers."

"Major, there is one thing I'd like to add," said Barret, stepping forward.

"What's that?" asked Connel.

"It's about the cadets," said Barret. "I talked to them just before they blasted off in the scout. They had a lot to say about your taking Corbett with you on the trip to Mars. They seemed disgruntled and dissatisfied."

Steve Strong whirled on the young engineer. "What did they say?" he demanded.

"Simply that they didn't feel that they were getting a fair deal with Tom being taken off guard duty, since he was actually responsible for them having it in the first place.

"They said that!" exclaimed Strong. "But how could that—" He suddenly closed his mouth and turned away, frowning.

"But how could what, Steve?" asked Walters.

"Nothing, sir," said Strong. "You have already reprimanded me too often as it is for speaking up in their behalf."

Walters lifted his eyebrows. "It appears to me that you're getting a little touchy!" he barked. "Watch yourself, Steve. Don't let your feelings for those boys get out of hand."

"Blast it!" exclaimed Professor Hemmingwell. "While you continue talking about those stupid cadets, you're just wasting my time. There's plenty of work to do and precious little time to do it in." He turned to Barret. "Come on, Dave, let's get this mess cleared away."

"Yes, sir," said Dave Barret.

As Hemmingwell and Barret turned their attention to the wrecked control panel, Connel, Walters, and Strong climbed out of the ship and left the hangar. On the slidewalk, headed back to the Academy, Commander Walters looked at Connel inquiringly.

"What now, Lou?" he asked.

"I have an idea, Commander," said Connel. "I'm going to spend the rest of the night listening to this audiotape over again. Then I'm going to do a little digging around."

"All right," said Walters. "And I suppose you'll want to talk to Manning and Astro when they get back."

Connel looked at Captain Strong grimly. "I want to talk to them so badly, I would crawl on my hands and knees to get to them right now."

Strong flushed angrily but said nothing, and as soon as the three officers arrived at the Academy grounds, he excused himself. He walked slowly and thoughtfully along, looking at the dormitories with unseeing eyes and hearing with deaf ears the noise of the cadets getting ready for bed. He could not believe that Roger or Astro had abandoned their posts, or that Tom would run off to disappear on Mars, just for the sake of disappearing. In all his years at the Academy, Strong had never met three boys who so exemplified the true spirit of Space Cadets. Something was wrong somewhere. But what?

Strong paused outside the huge recreation hall, watching the cadets. Tony Richards and the Capella unit walked by, and returning their salutes, Strong could only see Tom, Roger, and Astro.

A figure dressed in the black-and-gold uniform of an officer in the Solar Guard walked toward him. Strong's eyes lighted up with recognition.

"Joan!" he exclaimed. "What are you doing here?"

"Looking for you," she said. She had some papers in her hand and held them out to him.

"What's this?" he asked, glancing at them in the light reflected from the hall, and then back to the serious face of the brilliant young physicist, Dr. Joan Dale, who, in spite of being a woman, had been placed in charge of the Academy laboratories, the largest and most complete in the entire Solar Alliance.

"Steve," she began, "I was in charge of the psychograph tests taken of all the workers at the projectile operation after the first mishap—"

"How did you know about the second?" Strong interrupted quickly, remembering Connel's admonition about keeping the incident quiet.

"I was ordered to go over the graphs again, to look for any possible clue in a worker's mental make-up that would lead him to a criminal act." She paused and looked up at him squarely. "Do you suspect me too?"

"I'm sorry, Joan," said the young captain. "But this whole business is getting me down. Tom, disappearing on Mars, Roger and Astro walking off guard duty and stealing a scout, and now this latest sabotage attempt." He sighed and shook his head. "I'm tired I guess."

She smiled. "I understand, Steve, and regardless of what Major Connel and Commander Walters have said, I'll bet my last credit there's a good reason for what the boys have done."

Strong looked down at the pretty physicist and smiled. "Thanks, Joan," he said. "Now, what about these papers?"

"It's about the report on Pat Troy," she replied. "When we asked him if he was working with anyone other than the professor, he lied."

She produced a sheet of paper from among those she held and handed it to Strong. The young captain took it and scanned it quickly. The paper was ordinary graph paper with a series of small, wavy lines on it in red ink. Near the bottom of the paper, there was a jagged peak in the wavy line. "What does this mean?" he asked, pointing to the peak.

"That was his reaction when he was asked if he worked for anyone else."

"Does that mean it's a lie?"

"Yes. All the waves that you see," she continued, pointing to the line, "represent answers to questions about his personal life. Does he shave in the morning? Does he brush his teeth at night, and so forth. They're comparison questions to show his reaction when he tells the truth. That peak indicates a lie."

"Then," said Strong thoughtfully, "he might be the saboteur."

"Or know who it is," said Joan.

"I've got to get this information to Connel right away!" said Strong. "Can I have this paper?"

"Yes. I made copies. I was just going to take one to the commander when I saw you."

"I'll try to locate Major Connel and you go on and tell the commander what you've found. And Joan—" Strong hesitated.

"Yes?"

"Put in a good word for the cadets, will you?" Strong pleaded. "Both Connel and Commander Walters are all set to blast them right out of the service."

"I'll do what I can—" Suddenly Dr. Dale stopped, her eyes widening with fright. She pointed down the walk behind Strong.

Steve turned around and gasped. Connel was striding toward them grimly, followed by four guards carrying a stretcher covered by a blanket. Strong quickly recognized the outline of a human form beneath the blanket.

"Major," exclaimed Steve, "what—who—?"

"It's getting thicker by the hour, Steve!" said Connel in a low voice. "This is the first time in the history of the Academy that there has been what looks like"—he paused and turned to look at the draped body being carried past them—"an attempt at murder," he finished.

"Murder!" said Strong. "But—"

"Who is it?" demanded Joan.

"A little man who can tell us a great deal if and when he regains consciousness! Pat Troy!"