"Sound off, Corbett!"

Seated in the pilot's chair on the control deck of the rocket cruiser Polaris, Major Connel bellowed the order into the intercom as he scanned the many dials on the huge control board.

"One minute to touchdown, sir," reported Tom over the intercom from the radar bridge of the Polaris.

"One minute to touchdown," repeated Connel. "Right!"

Connel reached for the switches and levers that would bring the giant ship to rest on the red planet of Mars. Even after his many years in the Solar Guard and thousands of space flights, landing a rocket ship was still a thrill to the veteran spaceman, and knowing that he had a good man on the radar deck made it even more exciting and demanding of his skill.

"Decelerate!" yelled Tom over the intercom.

Connel shut down the main drive rockets and at the same time opened the nose braking rockets. "Braking rockets on!" he yelled.

"One thousand feet to touchdown," said Tom.

Connel watched the dials spinning before him.

"Seven hundred and fifty feet to touchdown," reported Tom.

"Keep counting, Corbett!" yelled Connel enthusiastically.

"Five hundred feet!"

Connel quickly cut back the nose braking rockets and again opened the main drive rockets as the ship plummeted tailfirst toward the surface of Mars.

"Two hundred feet!" came the warning call over the intercom.

Connel glanced up at the teleceiver screen over his head that showed the spaceport below. The concrete runways and platforms were rushing up to meet the giant ship. He opened the main rockets full.

"Seventy-five feet! Stand by!" yelled Tom.

Connel's hands flashed over the control panel of the ship, snapping switches, flipping levers, and turning dials in an effort to bring the ship to a smooth landing. There was a sudden roar of rockets and then a gentle bump.

"Touchdown!" roared Connel.

He flipped off the main switches on the control board, spun around in his chair, and noted the time on the astral chronometer. "Touchdown Marsport, 2117!" he announced.

Tom clambered down the ladder from the radar bridge and immediately noted the time of arrival in the logbook. He turned around and saluted the major sharply. "All secure, sir," he said.

"Congratulations on a smooth trip, Corbett," Connel said. "And thanks for letting me take her in. I know it's unusual to have the senior officer take over the ship, but once in a while I get the urge to put my hands on those controls and—well—" Connel paused, fumbling for words.

Tom was so startled by the major's stumbling attempt to explain his feelings, he felt himself blush. He had always suspected the major of being a rocket jockey at heart and now he was certain. But he would never tell anyone, not even Roger and Astro about this incident. It was something he knew that he himself would feel if he ever got to be as old as Major Connel and had reached his position. There passed between the officer and the cadet a sudden feeling of mutual understanding.

"I understand, sir," said Tom quietly.

"Dismissed!" roared Connel, recovering his composure again, and very conscious that he had exposed his innermost feelings to the cadet. But he didn't mind too much. Tom Corbett had proven beyond the shadow of a doubt that he had the stuff true spacemen are made of, and because of this, Connel could feel as close to him as a man near his own age. There was never a breed of men who were drawn so close together in their love of work as the spacemen and there was no need for further explanation.

When they had climbed out of the Polaris and stepped on the landing ramp at Marsport, Connel and Tom saw that the ground crews were already checking over the afterburners and exhaust tubes of the ship. A young Solar Guard lieutenant, wearing a decidedly greasy uniform, snapped to attention before Connel.

"Lieutenant Slick at your service, sir," he announced.

"Lieutenant," bawled Connel, "your uniform is filthy!"

"Yes, sir, I know it is, sir," replied the young officer. "But I was overhauling a firing unit this morning, sir, and I guess I got a little dirty."

"That is enlisted man's work, sir," stated Connel. "You are an officer."

"I know, sir, but—" Slick stammered. "Well, sir, once in a while I like to do it myself."

Tom turned away, hiding a smile. The young officer was expressing the same feelings Connel himself had uttered just a few minutes before. Connel cleared his throat, and with a sidelong glance at Tom and a wink, dismissed the young officer, ordering him to have a jet car sent for them right away.

"Take mine, sir," said the young officer, happy to have escaped Connel's wrath so easily. It was not too long ago that he had been a cadet at the Academy and he remembered all too clearly what Connel could do when he was mad.

When the jet car was brought up, Tom slipped behind the wheel, and with Connel seated beside him, he sent the sleek little vehicle roaring across the spaceport to the main administration building.

Inside the gleaming crystal building, Connel and Tom were escorted by a Space Marine guard to the office of the spaceport commander, Captain Jim Arnold. He and Connel knew each other well, and after quick greetings and the introduction of the young cadet, Connel asked for the latest reports on the projectile receivers.

"Lou, I've got good news for you," announced Arnold. "We've completed the receiver ramps for the test. As soon as your ship is ready to fire her cargo projectiles, we can receive them."

Connel's face showed the surprise he felt. "Why, Jim, that's the most amazing news I've ever heard!" he exclaimed. "How did you do it?"

"Through hard work," replied Arnold, "and the efforts of a young officer named Slick. He handled the whole thing."

"Slick!" exclaimed Connel. "I just bawled him out for wearing a dirty uniform."

"He's responsible for our success," asserted Arnold. "And what's more, those receivers can be taken apart and reassembled again in less than ten minutes."

"Incredible," gasped Connel. "I've got to see those things right away. Come along, Corbett."

Tom followed the major out of the office and back to the jet car. They were about to drive off to the opposite end of the field when they heard someone shout to them. Tom stopped the speedy little car and Connel turned around to see who had called them.

Carter Devers rushed up and greeted the Solar Guard officer enthusiastically. "Major, this is a surprise."

"Hello, Carter. What are you doing here?" Connel asked bluntly.

"Had some business here on Mars," said Devers. "I've finished and I'm on my way back to Earth. You wouldn't, by any chance, be going back soon, would you? I saw the Solar Guard cruiser come in and one of the attendants told me that they were preparing it for immediate blast-off—"

"Of course, Carter," Connel said briskly. "Get in. We're just going over to inspect the receivers and then we'll be heading back."

Devers jumped into the jet car and Tom headed across the broad expanse of the spaceport.

Connel turned to Devers and said enthusiastically, "Can you imagine, Devers? Some young officer here at Marsport has worked out a way to assemble and transport the receivers in a fantastically small amount of time."

"That's amazing," said Devers. "I'd like very much to see them." He looked at Tom and said, "Incidentally, who is your young friend?"

"Oh, sorry," replied Connel. "This is Cadet Corbett of the Polaris unit. No doubt you've heard of them. He and his unit mates manage to get into more trouble than all the monkeys in the Venusian jungle."

Carter laughed. "I've known Lou Connel long enough to know that when he says something like that about you, son, he thinks very highly of you."

"Thank you, sir," replied Tom, not knowing what else to say.

While Connel and Devers talked of the problems surrounding the projectile operation, Tom concentrated on his driving. He was following directions given him by Jim Arnold to reach the testing grounds and this made it necessary for Tom to drive right through the center of the spaceport, weaving in and out of the dozens of spaceships parked on the concrete ramps.

Tom swept past them, driving expertly, heading toward a group of concrete blockhouses enclosed by a fence which he knew would be the testing area. Beside the fence, a short, stubby-nosed spaceship was loading cargo, and beneath the vessel, two huge jet trucks were backing into position. Tom steered the car up to the gate and stopped at the signal of an armed guard. Connel, Devers, and Tom stepped out of the car and waited for a minute, and then young Lieutenant Slick appeared, wearing a clean uniform.

Slick checked their names off against a list he carried and then drew Connel to one side. "I'm sorry, sir," he said, just out of Tom and Dever's hearing, "I can't allow the cadet inside this area."

"Why not?" asked Connel. "I'll vouch for him."

"I'm sorry, sir," said Slick. "Those are my orders. I can let you and Mr. Devers in, but not Cadet Corbett." He showed Connel a list of names: Connel, Strong, Hemmingwell, Walters, Devers, and Barret. They were the only names on it.

Connel nodded. "I understand," he said and turned to Tom. "You'll have to stay here, Corbett," he called. "Wait for me in the car."

"Yes, sir," replied Tom and hopped back in the jet.

He backed out through the gate, pulling up alongside the fence near the stubby-nosed freighter. When Connel and Devers, escorted by Slick, had disappeared behind a blockhouse inside the restricted area, Tom casually walked over to watch the loading operation of the spaceship. A few of the workers stopped when he walked up, and recognizing his cadet uniform, greeted him warmly.

"Space Cadet, eh?" said one of the men. "Sure wish I could get my boy in the Academy."

"Me too," said another man. "All I hear from morning until night is Space Academy—Space Academy."

Tom smiled his appreciation of their admiration. While he answered their questions about the training school of the Solar Guard, they continued working. After a while the conversation turned to the restricted area behind the fence.

"Some pretty important work going on in there," said one of the men. "But how come they wouldn't let you go in?"

"I haven't been cleared by security," replied Tom. "It's top secret."

"Secret," said a man who had just joined the group. Tom had noticed him before, climbing out of one of the huge jet trucks parked near the gate. "Why, there ain't nothing secret about what's going on in there," he continued.

"Why do you say that?" asked Tom alertly.

"Why, we all know about it, Cadet," said one of the first men Tom had spoken to. "They're building receivers for cargo projectiles."

Tom gulped in surprise. "But how did you know?" he asked.

"Why, it's the only thing we've been talking about down at the garage and at Sloppy Sam's, the jet-truckers hangout," replied the trucker. "If this thing works, surface transportation will be finished."

"That's right," asserted another worker. "The whole industry will be wiped out overnight. Nobody will have anything trucked any more. Cargo'll be loaded into a projectile and shot off into space to a passing freighter. Then the freighter carries it to its destination and shoots it back down to a receiver."

"But how could you know all this?" asked Tom. "It is one of the Solar Guard's most closely guarded secrets."

"It's all over Mars," declared the truck driver with a derisive laugh. "Why, everybody knows it."

Suddenly one of the men yelled and pointed toward the fence. The jet truck parked near the gate was rolling forward slowly. As Tom and the men watched in horror, the giant vehicle crashed through the fence and rolled into the restricted area, picking up speed.

In a flash Tom was inside the jet car, driving right through the hole in the fence and speeding after the huge machine. Around him, guards were running after the truck, shouting frantic warnings. Far ahead of him, Tom saw Major Connel and Devers standing near several receivers lined up outside a blockhouse. The truck was rolling straight toward them. Hearing the shouts of alarm, the two men turned and saw their danger. Devers immediately jumped into the safety of the blockhouse, but Connel stumbled and fell heavily. Tom's blood ran cold. He saw that the major had struck his head against one of the receivers and he lay on the ground, dazed and unable to move.

Tom jammed the accelerator of the tiny jet car to the floor and shot ahead like a rocket. He was alongside the truck now, but the distance between the huge machine and Connel was narrowing rapidly. Tom clenched his teeth and urged the little car on faster. He knew that there was not enough time for him to jump into the truck and pull the brake. There was only one thing he could do.Regaining his senses, Connel tried to crawl to safety, but there was no time. He braced himself for what he knew would be instant death, and then to his amazement he saw Tom's jet car swerve sharply in front of the runaway truck.

There was a wrenching crash of metal, a shrill scream of skidding tires, climaxed by a thunderous roar. After that, deathly silence.

For a second Connel stood frozen in horror, staring at the overturned truck and the tangle of twisted metal that was the jet car. Then he lunged forward with a frantic cry.

"Corbett! Corbett!"