"We passed!"

Tom turned away from the lists posted on the dormitory bulletin board and with his arms around Astro and Roger pushed through the knot of cadets.

"Yeow!" bellowed Astro.

"We made it," murmured Roger with a note of disbelief in his voice. "We made it!" And then, with the realization that he was still a Space Cadet for at least another term, he turned and began pounding Astro on the back. "You big Venusian ape, we made it."

Arm in arm, the three cadets strolled across the quadrangle and shouted to friends they passed. Occasionally they fell silent when they saw a boy carrying his gear to the supply building. These had failed to pass the rigid examinations.

Near the Tower of Galileo, the cadets came face to face with Tony Richards, McAvoy, and Davison. The two units looked at each other silently, remembering what had happened only four short weeks before. Then they all smiled and pounded each other on the back, congratulating each other on passing. Neither of the units had made top honors as a result of their fight and the trial, and having to spend so much time on guard duty, but they had passed and that was the most important thing. The boys all adjourned to the credit exchange and gorged themselves on Martian fruit pies covered with ice cream. Finally the party broke up when Tom remembered that he and his unit mates had to go on guard duty in half an hour.

"Well," said Tony Richards, rising, "we relieve you guys at midnight, so we might as well hit the sack right now. I've been waiting for this night for a long time."

"No study," sighed Davison. "What heaven! I feel as if I've been pardoned from prison."

The three boys of the Capella crew said good-by to Tom, Roger, and Astro, and walked off. Tom settled back in his chair and sighed. "Sure wish I was in their boots," he said. "I don't see how I'm going to get through tonight."

"Don't think about it," said Roger. "Only seven more days to go, and then we go on summer cruise with the Polaris."

"I can't wait to get back on that power deck," said Astro. "It'll be like going home."

Later, riding the new slidewalk to the area where the huge hangar had been built, they saw Captain Strong returning from the restricted area on the other slidewalk. They hopped off their walk and waited for the young officer.

"I'm happy that you passed the exams, boys," he said. "And I want you to know Commander Walters and Major Connel think a lot more of you, though they wouldn't admit it, for the way you worked to make it."

"Thank you, sir," said Astro respectfully.

"You'll have to excuse us, sir," said Tom. "We've got to get out to the hangar and go on guard."

"Yes, and you'd better hurry," said Strong. "After that mix-up with Dave Barret, Firehouse Tim has his eye on you. Barret put up quite a fuss about it."

"I still don't see how Mr. Barret got in there," said Tom. "The fourth side of the hangar faces the hills, and we three covered the other three sides."

"However he got in," interrupted Strong, "he had a right to be there. And he also had a right to carry sidearms."

"Captain Strong," said Roger, "we've talked about it a lot, the three of us. And we decided that regardless of what Major Connel or Firehouse or Barret have said, we'd do the same thing, in the same way again."

"I think you're perfectly right, Manning. But don't quote me," said Strong, his voice serious. "This is one of the most important projects I've ever been connected with and—" He stopped suddenly. "Well, I can't tell you any more. That's how tight the security is on it."

"But everyone knows that it's a projectile that will home on a target, sir," said Tom.

"Yes, that was given to the stereos for general news release, but there are other factors involved, factors so important that they could revolutionize the whole concept of space flight."

"Wow!" said Tom. "No wonder they have this place so well guarded."

"Humph," snorted Roger. "I'd give up the opportunity of guarding this revolutionary secret for one night's good sleep."

"You'll get that tomorrow when we go off duty," said Tom. "And please, Roger, no blunders tonight, eh? Let's not take any chances of losing the summer cruise in the Polaris."

"Listen! You want to talk to the Venusian hick about that, not me," declared Roger. "He's the one that spotted Barret."

"But you hit him on the head," growled Astro. "You and your catlike reflexes." The big cadet referred to a recent letter he had seen in which one of the blond-haired cadet's many space dolls referred to his sensitivity as being that of a poet, and his dancing as smooth as the reflexes of a cat.

Roger spun on the big cadet. "You blasted throwback to a Venusian ape!" he roared. "If I ever catch you reading my mail again—"

"You'll what?" growled Astro. "You'll do just exactly what?" He grabbed Roger by the arm and held him straight out, so that he looked as if he were hanging from a tree.

Strong laughed and shook his head. "I give you three to the loving, tender care of Firehouse Tim," he said, hopping over on the moving slidewalk, back to the Academy.

"Put me down, you overgrown idiot," Roger howled.

"Not until you promise not to threaten me with violence again," said Astro with a wink at Tom. The young curly-haired cadet doubled up with laughter. Finally Roger was lowered to the ground, and, though he rubbed his shoulder and grumbled, he was really pleased that Astro felt like roughhousing with him. The events of the last few weeks had so tired all of them that there had been no energy left for play.

Lightheartedly they stepped over to the slidewalk and were back on their way to the secret project.

Two huge wire fences had been built around the hangar area now, fences carrying a surge of paralyzing power ready to greet anyone that dared touch it. More than twenty feet high, the outer fence was buried six feet into the ground and was some hundred yards away from the hangar building itself, and fifty yards away from the second fence. The entire area was also guarded by radar. Should any unauthorized person or object be found in that area, an automatic alarm sounded and in fifteen seconds a hundred fully armed guards were ready for action. The men who had been cleared by security to work in and around the restricted area wore specially designed belts of sensitized metal that offset the effects of the radar. But the fence was still the untouchable for everyone.

Tom, Roger, and Astro had now been moved inside the hangar itself, to stand guard over the only three doors in the cavernous structure. They were armed with powerful heat blasters. These rifles were different from the paralo-ray guns they had used previously. A beam of light from the ray guns would only paralyze a human being, while the blaster destroyed anything it touched, burning it to a crisp.

As soon as the three cadets saw the change in armament, they knew they were guarding something so secret that human life, if it interfered with the project, would be disintegrated. Only once before, on a hunting trip to Venus, had they ever used the blasters, but they knew the deadly power of the weapons.

Nothing was said to them. Firehouse Tim had not posted any special orders or given them any special instructions. Each man who worked inside the hangar had to pass a simple but telling test of identification. On a table at each entrance to the hangar was a small box with a hole in the top. Each worker, guard, and person that entered the hangar had to insert a key into the hole and it made contact with a highly sensitive electronic device inside. The keys were issued only by Major Connel or Captain Strong, and should anyone attempt to enter the hangar without it, or should the key not make the proper contact, lighting up a small bulb on the top of the box, Tom, Roger, and Astro had simple instructions: Shoot to kill.

This form of identification had been employed for some time now, even before the wire fence had been installed, but the really spectacular change was in the heat blasters each guard carried. This, more than anything else, impressed on everyone connected with the project, that to move the wrong way, to say the wrong thing, or to act in any suspicious manner might result in instant death.

It was a mark of trust that Tom, Roger, and Astro had been placed in such a highly sensitive position. They could kill a man and simply explain, "The light didn't go on!" and that would be the end of it. Neither of them knew that Connel had specifically requested that they be assigned to the day shift, when the hangar would be crowded with workers, who, intent on their assigned jobs, might be careless and leave themselves open to instant action on the part of the guards. Connel reasoned that Tom, Roger, and Astro, aside from their occasional antics in the Academy, would be more responsible than rough enlisted spacemen. The orders were specific: shoot to kill, but there was almost always one poor human being who would forget. In spite of the necessity for tight security, Connel felt he had to allow for that one percent of human failure. Secretly he was very happy that he had a crack unit like the Polaris to place in such a job. And the Capella unit had been entrusted with the same responsibility.

It was under such tight conditions that Astro, watching the least busy of the three entrances and exits, saw Dave Barret walk to a nearby public teleceiver booth, and, with the door ajar, place a transspace call to Venusport.

The booth was used often by the workers and Astro did not think much of it, until he accidentally overheard Barret's conversation.

"... Yeah, I know, but things are so tight, I can't even begin to get at it." Barret had his mouth close to the transmitter and his voice was low, but Astro could still hear him. "Yeah, I know how important it is to you, but I can be burned to a cinder if I make one false move. You'll just have to wait until I find an opening somewhere. Good-by!"

Barret switched off the teleceiver set and stepped out of the booth to face the muzzle of Astro's blaster. "Stand where you are!" growled the big cadet.

"What, why you—" Barret clamped his mouth shut. There was a difference between being frozen and being blasted into a crisp.

Astro reached over and touched the button that would alert a squad of guards, Major Connel, and Tim Rush. In a flash the alarm sounded throughout the hangar and troopers stormed in brandishing their guns. Firehouse Tim and Connel arrived seconds later. They skidded to a stop when they saw Barret with his hands in the air and Astro's finger on the trigger of the blaster.

"By the blessed rings of Saturn!" roared Connel. "Not again."

"Put down that gun," demanded Rush, stepping forward quickly. Astro lowered the gun and Barret dropped his hands.

"What's the meaning of this?" demanded Connel, his face reddening with rage.

Astro turned and looked the major right in the eye. "Major," he said calmly, "this man just made a teleceiver call—a transspace call to Venusport."

"Well, what about it?" cried Barret.

"Sir," said Astro, unruffled by Barret's screaming protest, "this man spoke of getting at something, and that he was unable to do so, because he might be burned to a cinder. And the other party would have to wait until he found an opening."

"What!" exclaimed Connel, turning to look at Barret. "What is the meaning of this, Barret?"

"Why, that knuckle-headed baboon!" yelled Barret. "Sure, I made a transspace call to Venusport—to the Venusian Atomic By-Products Corporation."

"What was the call about?" demanded Connel.

The guards had not moved and the workers in the hangar were now gathering around the small knot of men by the teleceiver booth.

"Why—I—"

"Come on, man!" shouted Connel. "Out with it."

"I called about getting a new timer for the projectile fuel-injection system," snapped Barret. "The timer is too slow for our needs. I wanted to adjust it myself, but the projectile is so compact, I can't get at it without taking a chance of getting doused by the fuel."

"What about that remark about finding an opening?" growled Connel.

"What's going on here?" called Professor Hemmingwell as he bustled up to the group. "Why aren't these men working? Dave, why aren't you up there—?"

"Just a minute, Professor!" Connel barked, and turned back to Barret. "Go ahead, Barret."

"They can't make a new timer until I find a way of installing it without taking apart the whole projectile," said Barret, adding sarcastically, "in other words, Major—finding an opening."

"All right," barked Connel. "That's enough." He turned to the assembled workers. "Get back to work, all of you." The men moved away and Firehouse Tim led the guards back to their quarters. Professor Hemmingwell, Barret, and Astro remained where they were.

Connel turned to Astro. "Good work, you dumb Venusian," he snorted. "But so help me, if you had burned this man, I, personally, would've buried you on a prison rock." The major then turned to Barret. "As for you—" he snarled.

"Yes?" asked Barret coolly.

"You make one more call like that over a public teleceiver," Connel roared, "especially a transspace call that's monitored by the idiots in the teleceiver company, and I'll send you to a prison asteroid!"

"Now, Major," said Hemmingwell testily, "I don't think you should speak to Dave that way. After all, he's a very valuable man in this project."

"How valuable would he be if this cadet had gone ahead and blasted him?" snarled Connel.

"It's just another example of how these stupid boys have obstructed my work here," replied Hemmingwell angrily. "I can't see why they have to interfere this way. And they always pick on poor Dave."

"Yes," snarled Barret. "I'm getting pretty tired of being a clay pigeon for a bunch of brats." He turned to Astro. "You'll have a head full of socket wrench if you mess with me again."

"You'll get a receipt, Barret," growled Astro. "Paid in full."

"All right, break it up," growled Connel. "Back to your post, Astro. And you get back to work, Barret, and remember what I said about using that public teleceiver."

Barret and Hemmingwell walked off, with the little professor talking rapidly to the younger scientist, trying to calm his anger.

Astro, Tom, and Roger were extraordinarily strict about the exit of the workers that night and there was angry muttering in the ranks of the men who wanted to get home. But the three cadets refused to be hurried and made each man perform the ritual of getting out to the letter. Still later, after they had been relieved by the Capella unit and had told them of the incident between Astro and Barret, they headed back to the Academy dormitory more tired than they had ever been before in their lives. Thirty seconds after reaching their room, they were asleep in their bunks, without undressing or washing. Like whipped dogs, they sprawled on their bunks, dead to the world.