"Emergency air lock open!"

The tall, broad-shouldered officer, wearing the magnificent black-and-gold uniform of the Solar Guard, spoke into a small microphone and waited for an acknowledgment. It came almost immediately.

"Cadet Corbett ready for testing," a voice crackled thinly over the loud-speaker.

"Very well. Proceed."

Seated in front of the scanner screen on the control deck of the rocket cruiser Polaris, Captain Steve Strong replaced the microphone in its slot and watched a bulky figure in a space suit step out of the air lock and drift away from the side of the ship. Behind him, five boys, all dressed in the vivid blue uniforms of the Space Cadet Corps, strained forward to watch the lone figure adjust the nozzles of the jet unit on the back of his space suit.

"Come on, Tom!" said the biggest of the five boys, his voice a low, powerful rumble as he rooted for his unit mate.

"If Tom makes this one," crowed the cadet next to him, a slender boy with a thick shock of close-cropped blond hair, "the Polaris unit is home free!"

"This is the last test, Manning," replied one of the remaining three cadets, the insigne of the Arcturus unit on the sleeve of his uniform. "If Corbett makes this one, you fellows deserve to win."

Aboard the rocket cruiser Polaris, blasting through the black void of space two hundred miles above Earth, six Space Cadets and a Solar Guard officer were conducting the final test for unit honors for the term. All other Academy units had been eliminated in open competition. Now, the results of the individual space orientation test would decide whether the three cadets of the Arcturus unit or the three cadets of the Polaris unit would win final top unit honors.

Roger Manning and Astro kept their eyes glued to the telescanner screen, watching their unit mate, Tom Corbett, drift slowly through space toward his starting position. The young cadet's task was basically simple; with his space helmet blacked out so that he could not see in any direction, he was to make his way back to the ship from a point a mile away, guided only by the audio orders from the examining officer aboard the ship. His score was measured by the time elapsed, and the amount of corrections and orders given by the examining officer. It was an exercise designed to test a cadet's steadiness under emergency conditions of space.

The three members of the Arcturus unit had completed their runs and had returned to the ship in excellent time. Roger and Astro had also taken their tests and now it depended on Tom. If he could return to the Polaris in less than ten minutes, with no more than three corrections, the Polaris unit would be victorious.

Seated directly in front of the scanner, Captain Steve Strong, the examining officer, watched the space-suited figure dwindle to a mere speck on the screen. As the regular skipper of the Polaris crew, he could not help secretly rooting for Tom, but he was determined to be fair, even to the extent of declaring the Arcturus unit the winner, should the decision be very close. He leaned forward to adjust the focus on the scanner, bringing the drifting figure into a close-up view, and then lifted the microphone to his lips.

"Stand by, Corbett!" he called. "You're getting close to range."

"Very well, sir," replied Tom. "Standing by."

Behind Strong, Roger and Astro looked at each other and turned back to the screen. As one, they crossed the fingers of both hands.

"Ready, Corbett!" called Strong. "You'll be clocked from the second you're on range. One hundred feet—seventy-five—fifty—twenty-five—ten—time!"

As the signal echoed in his blacked-out space helmet, Tom jerked his body around in a sudden violent move, and grasping the valve of the jet unit on his back, he opened it halfway. He waited, holding his breath, expecting to hear Captain Strong correct his course. He counted to ten slowly, and when no correction came over the headphones, he opened the valve wide and blindly shot through space.

Aboard the Polaris, Astro and Roger shouted with joy and Strong could not repress a grin. The tiny figure on the scanner was hurtling straight for the side of the Polaris!

As the image grew larger and larger, anxious eyes swiveled back and forth from the scanner screen to the steady sweeping hand of the chronometer. Roger bit his lip nervously, and Astro's hands trembled.

When Tom reached a point five hundred feet away from the ship, Strong flipped open the audio circuit and issued his first order.

"Range five hundred feet," he called. "Cut jets!"

"You're already here, spaceboy!" yelled Roger into the mike, leaning over Strong's shoulder. The captain silenced him with a glare. No one could speak to the examinee but the testing officer.

Tom closed the valve of his jet unit and blindly jerked himself around again to drift feet first toward the ship. Strong watched this approach closely, silently admiring the effortless way the cadet handled himself in weightless space. When Tom was fifty feet away from the ship, and still traveling quite fast, Strong gave the second order to break his speed. Tom opened the valve again and felt the tug of the jets braking his acceleration. He drifted slower and slower, and realizing that he was close to the hull of the ship, he stretched his legs, striving to make contact. Seconds later he felt a heavy thump at the soles of his feet, and within the ship there was the muffled clank of metal boot weights hitting the metal skin of the hull.

"Time!" roared Strong and glanced at the astral chronometer over his head. The boys crowded around as the Solar Guard captain quickly computed Tom's score. "Nine minutes, fifty-one seconds, and two corrections," he announced, unable to keep the pride out of his voice.

"We win! We win!" roared Roger. "Term honors go to the Polaris!"

Roger turned around and began pounding Astro on the chest, and the giant Venusian picked him up and waltzed him around the deck. The three members of the Arcturus unit waited until the first flush of victory died away and then crowded around the two boys to congratulate them.

"Don't forget the cadet who did it," commented Strong dryly, and the five cadets rushed below to the jet-boat deck to wait for Tom.

When Tom emerged from the air lock a few moments later, Roger and Astro swarmed all over him, and another wild dance began. Finally, shaking free of his well-meaning but violent unit mates, he grinned and gasped, "Well, from that reception, I guess I did it."

"Spaceboy"—Roger smiled—"you made the Arcturus unit look like three old men in a washtub counting toes!"

"Congratulations, Corbett," said Tony Richards of the Arcturus crew, offering his hand. "That was really fast maneuvering out there."

"Thanks, Tony." Tom grinned, running his hand through his brown curly hair. "But I have to admit I was a little scared. Wow! What a creepy feeling to know you're out in space alone and not able to see anything."

Their excitement was interrupted by Strong's voice over the ship's intercom. "Stand by, all stations!"

"Here we go!" shouted Roger. "Back to the Academy—and leave!"

"Yeeeeooooow!" Astro's bull-like roar echoed through the ship as the cadets hurried to their flight stations.

As command cadet of the Polaris, Tom climbed up to the control deck, and strapping himself into the command pilot's seat, prepared to get under way. Astro, the power-deck cadet who could "take apart a rocket engine and put it back together again with his thumbs," thundered below to the atomic rockets he loved more than anything else in the universe. Roger Manning, the third member of the famed Polaris unit, raced up the narrow ladder leading to the radar bridge to take command of astrogation and communications.

While Captain Strong and the members of the Arcturus unit strapped themselves into acceleration cushions, Tom conducted a routine check of the many gauges on the great control panel before him. Satisfied, he flipped open the intercom and called, "All stations, check in!"

"Radar deck, aye!" drawled Roger's lazy voice.

"Power deck, aye!" rumbled Astro.

"Energize the cooling pumps!" ordered Tom.

"Cooling pumps, aye!"

The whine of the mighty pumps was suddenly heard, moaning eerily throughout the ship.

"Feed reactant!"

The sharp hiss of fuel being forced into the rocket engines rose above the whine of the pumps, and the ship trembled.

"Stand by to blast," called Tom. "Standard space speed!"

Instantly the Polaris shot toward Earth in a long, curving arc. Moments later, when the huge round ball of the mother planet loomed large on the scanner screen, Roger's voice reported over the intercom, "Academy spaceport control gives us approach orbit 074 for touchdown on Ramp Twelve, Tom."

"074 Ramp Twelve," repeated Tom. "Got it!"

"Twelve!" roared Astro suddenly over the intercom. "Couldn't you make it closer to the Academy than that, Manning? We'll have to walk two miles to the nearest slidewalk!"

"Too bad, Astro," retorted Roger, "but I guess if I had to carry around as much useless muscle and bone as you do, I'd complain too!"

"I'm just not as lucky as you, Manning," snapped Astro quickly. "I don't have all that space gas to float me around."

"Knock it off, fellows," interjected Tom firmly. "We're going into our approach."

Lying on his acceleration cushion, Strong looked over at Tony Richards of the Arcturus unit and winked. Richards winked and smiled back. "They never stop, do they, sir?"

"When they do," replied Strong, "I'll send all three of them to sick bay for examination."

"Two hundred thousand feet to Earth's surface," called Tom. "Stand by for landing operations."

As Tom adjusted the many controls on the complicated operations panel of the ship, Roger and Astro followed his orders quickly and exactly. "Cut main drive rockets and give me one-half thrust on forward braking rockets!" ordered Tom, his eyes glued to the altimeter.

The Polaris shuddered under the sudden reverse in power, then began an upward curve, nose pointing back toward space. Tom barked another command. "Braking rockets full! Stand by main drive rockets!"

The sleek ship began to settle tailfirst toward its destination—Space Academy, U.S.A.

In the heart of a great expanse of cleared land in the western part of the North American continent, the cluster of buildings that marked Space Academy gleamed brightly in the noon sun. Towering over the green grassy quadrangle of the Academy was the magnificent Tower of Galileo, built of pure Titan crystal which gleamed like a gigantic diamond. With smaller buildings, including the study halls, the nucleonics laboratory, the cadet dormitories, mess halls, recreation halls, all connected by rolling slidewalks—and to the north, the vast area of the spaceport with its blast-pitted ramps—the Academy was the goal of every boy in the year A.D. 2353, the age of the conquest of space.

Founded over a hundred years before, Space Academy trained the youth of the Solar Alliance for service in the Solar Guard, the powerful force created to protect the liberties of the planets. But from the beginning, Academy standards were so high, requirements so strict, that not many made it. Of the one thousand boys enrolled every year, it was expected that only twenty-one of them would become officers, and of this group, only seven would be command pilots. The great Solar Guard fleet that patrolled the space lanes across the millions of miles between the satellites and planets possessed the finest, yet most complicated, equipment in the Alliance. To be an officer in the fleet required a combination of skills and technical knowledge so demanding that eighty per cent of the Solar Guard officers retired at the age of forty.

High over the spaceport, the three cadets of the Polaris unit, happy over the prospect of a full month of freedom, concentrated on the task of landing the great ship on the Academy spaceport. Watching the teleceiver screen that gave him a view of the spaceport astern of the ship, Tom called into the intercom, "One thousand feet to touchdown. Cut braking rockets. Main drive full!"

The thunderous blast of the rockets was his answer, building up into roaring violence. Shuddering, the great cruiser eased to the ground foot by foot, perfectly balanced on the fiery exhaust from her main tubes.

Seconds later the giant shock absorbers crunched on the ramp and Tom closed the master switch cutting all power. He glanced at the astral chronometer over his head and then turned to speak into the audio log recorder. "Rocket cruiser Polaris completed space flight one-seven-six at 1301."

Captain Strong stepped up to Tom and clapped him on the shoulder. "Secure the Polaris, Tom, and tell Astro to get the reactant pile from the firing chamber ready for dumping when the hot-soup wagon gets here." The Solar Guard officer referred to the lead-lined jet sled that removed the reactant piles from all ships that were to be laid up for longer than three days. "And you'd better get over to your dorm right away," Strong continued. "You have to get ready for parade and full Corps dismissal."

Tom grinned. "Yes, sir!"

"We're blasting off, sir," said Tony Richards, stepping forward with his unit mates. "Congratulations again, Corbett. I still can't figure out how you did it so quickly!"

"Thanks, Tony," replied Tom graciously. "It was luck and the pressure of good competition."

Richards shook hands and then turned to Strong. "Do I have your permission to leave the ship, sir?" he asked.

"Permission granted," replied Strong. "And have a good leave."

"Thank you, sir."

The three Arcturus cadets saluted and left the ship. A moment later Roger and Astro joined Strong and Tom on the control deck.

"Well," said Strong, "what nonsense have you three planned for your leave? Try and see Liddy Tamal. I hear she's making a new stereo about the Solar Guard. You might be hired as technical assistants." He smiled. The famous actress was a favorite of the cadets. Strong waited. "Well, is it a secret?"

"It was your idea, Astro," said Roger. "Go ahead."

"Yeah," said Tom. "You got us into this."

"Well, sir," mumbled Astro, turning red with embarrassment, "we're going to Venus."

"What's so unusual about going to Venus?" asked Strong.

"We're going hunting," replied Astro.

"Hunting?"

"Yes, sir," gulped the big Venusian. "For tyrannosaurus."

Strong's jaw dropped and he sat down suddenly on the nearest acceleration cushion. "I expected something a little strange from you three whiz kids." He laughed. "It would be impossible for you to go home and relax for a month. But this blasts me! Hunting for a tyrannosaurus! What are you going to do with it after you catch it?" He paused and then added, "If you do."

"Eat it," said Astro simply. "Tyrannosaurus steak is delicious!"

Strong doubled with laughter at the seriousness of Astro's expression. The giant Venusian continued doggedly, "And besides, there's a bounty on them. A thousand credits for every tyranno head brought in. They're dangerous and destroy a lot of crops."

Strong straightened up. "All right, all right! Go ahead! Have yourselves a good time, but don't take any unnecessary chances. I like my cadets to have all the arms and legs and heads they're supposed to have." He paused and glanced at his watch. "You'd better get hopping. Astro, did you get the pile ready for the soup wagon?"

"Yes, sir!"

"Very well, Tom, secure the ship." He came to attention. "Unit, stand—to!"

The three cadets stiffened and saluted sharply.

"Unit dismissed!"

Captain Strong turned and left the ship.

Hurriedly, Tom, Roger, and Astro checked the great spaceship and fifteen minutes later were racing out of the main air lock. Hitching a ride on a jet sled to the nearest slidewalk, they were soon being whisked along toward their quarters. Already, cadet units were standing around in fresh blues waiting for the call for final dress parade.

At exactly fifteen hundred, the entire Cadet Corps stepped off with electronic precision for the final drill of the term. By threes, each unit marching together, with the Polaris unit walking behind the standard bearers as honor unit, they passed the reviewing stand. Senior officers of the Solar Guard, delegates from the Solar Alliance, and staff officers of the Academy accepted their salute. Commander Walters stood stiffly in front of the stand, his heart filled with pride as he recognized the honor unit. He had almost washed out the Polaris unit in the beginning of their Academy training.

Major Lou Connel, Senior Line Officer of the Solar Guard, stepped forward when the cadets came to a stop and presented Tom, Roger, and Astro with the emblem of their achievement, a small gold pin in the shape of a rocket ship. He, too, had had his difficulties with the Polaris unit, and while he had never been heard to compliment anyone on anything, expecting nothing but the best all the time, he nevertheless congratulated them heartily as he gave them their hard-won trophy.

After several other awards had been presented, Commander Walters addressed the Cadet Corps, concluding with "... each of you has had a tough year. But when you come back in four weeks, you'll think this past term has been a picnic. And remember, wherever you go, whatever you do, you're Space Cadets! Act like one! But above all, have a good time! Spaceman's luck!"

A cadet stepped forward quickly, turned to face the line of cadets, and held up his hands. He brought them down quickly and words of the Academy song thundered from a thousand voices.

"Dis-missed!" roared Walters. Immediately the precise lines of cadets turned into a howling mob of eager boys, everyone seemingly running in a different direction.

"Come on," said Roger. "I've got everything set! Let's get to the station ahead of the mob."

"But what about our gear?" said Tom. "We've got to get back to the dorm."

"I had it sent down to the station last night. I got the monorail tickets to Atom City last week, and reserved seats on the Venus Lark two weeks ago! Come on!"

"Only Roger could handle it so sweetly," sighed Astro. "You know, hotshot, sometimes I think you're useful!"

The three cadets turned and raced across the quadrangle for the nearest slidewalk that would take them to the Academy monorail station and the beginning of their adventure in the jungles of Venus.