"Stand by to raise ship!"

Connel's bull-throated roar blasted through the intercom of the gleaming projectile ship from the power deck where Dave Barret was stationed, up to the radar bridge where Professor Hemmingwell waited anxiously.

On the main deck, seated at the controls, Connel spoke rapidly into the audioceiver microphone. "Projectile vessel to spaceport traffic control," he called. "Request blast-off clearance!"

"Spaceport traffic control to Connel," came a voice in reply over the audioceiver. "You are cleared. Your time is two minutes to zero!"

Connel began snapping the many levers and switches on the control panel in proper sequence, keeping a wary eye on the astral chronometer over his head as one of its red hands ticked off the seconds to blast-off.

The teleceiver screen to his right showed a view of the stern of the vessel and Connel could see some of the ground crew slowly rolling away the boarding equipment. Flipping on the switch that opened a circuit to an outside loud-speaker, he bellowed an order for the area to be cleared. The crew scurried back behind the blast deflectors and watched the ship through the thick crystal viewports.

"Power deck," Connel called into the intercom, "check in!"

"Power deck, aye!" reported Barret.

"Radar deck, check in!"

"Radar deck, aye!" Professor Hemmingwell acknowledged in a thin voice.

"Feed reactant!" Connel ordered.

"Reactant feeding at D-9 rate," said Barret after a split-second pause.

"Energize cooling pumps!"

"Cooling pumps, aye!"

"Cut in take-off gyros!"

"Gyros on," repeated Barret.

"All clear forward and up!" replied the elderly man.

"Right!" bawled Major Connel. "Stand by!"

Tensely he watched the red hand crawl up the face of the chronometer and he gripped the intercom microphone tightly. "Blast off," he began, "minus five, four, three, two, one, zero!"

Connel slammed home the master control switch and in an instant the silver ship trembled under a tremendous surge of power. Flame and smoke poured out of its exhaust and slowly it began to reach for sky, straining as if to break invisible bonds holding it to Earth. Her jets shrieking torturously, the ship picked up speed and then suddenly, as though shot from a cannon, it blasted up through the atmosphere—spacebound.

A moment later, on the control deck of the ship, Major Connel swung forward in his chair, shook off the effects of the tremendous acceleration, and called into the intercom, "Switch on the gravity generators!"

As soon as the artificial gravity was in effect, the officer put the ship on standard cruising speed, changed course slightly to put them on a direct heading to Mars, and then ordered Barret and Hemmingwell to the control deck.

"Well, Professor," he said as he gave the old man a hearty handshake, "so far so good. She handles like a baby carriage. If the projectiles work half as well, you'll really have yourself something!"

Professor Hemmingwell smiled appreciatively and turned to Barret, who was just climbing through the hatch from the power deck. "You've done as much as anyone to help this ship get into space, Dave," he said. "Thank you!"

"Think nothing of it, Professor," replied Barret airily.

"Well, shall we begin the first series of tests?" asked Connel.

"By all means!" said the professor enthusiastically. "If you and Dave will check the firing stations, I'll take care of the paper work!"

"Right," replied Connel. "Let's go, Barret!"

"I'll work outside, Major," said Barret, turning toward the air lock. "You see that all the firing chambers are properly loaded."

"Anything you say, Barret."

The two men turned away from the smiling professor and left the control deck. They separated in the companionway, Connel hurrying to the starboard firing chambers and Barret going to the midships air lock where he put on a space suit for his task out on the hull.

In two minutes the young scientist was out on the odd-looking blisters that marked the exterior of the firing chambers ringing the hull.

At each blister Barret examined the hollow firing tube carefully. In several he made delicate adjustments to a small metallic ring extending from the opening of the tube. The ring was one of the most important parts of the firing unit, emitting the long-range electronic beam controlling the flight of the projectile.

Meanwhile, inside the ship, Connel checked the loading of each of the chambers, making certain that each of the ten-foot-long torpedolike projectiles was properly secured in its blasting cradle. After fifteen minutes and a complete trip around the ship, the major was satisfied that all was in readiness. He returned to the control deck, meeting Barret on the way, and they found Professor Hemmingwell just completing his calculations for the initial test. He turned to them, waving a paper in front of their eyes.

"Gentlemen," he said proudly, "we are almost ready. If you will adjust course fifteen degrees to port, we'll be in proper position for the test!"

"Right," nodded Connel. "Stand by below, Barret."

"On my way," replied Barret, disappearing through the hatch.

"Well, Professor," said Connel, walking to the controls, "this is the big moment!"

"Yes," nodded Hemmingwell. "If these rocket projectiles prove workable now, there's nothing to stop us from carrying on with our test of the ground receivers on Mars immediately."

"Power deck to control deck, check in!" Barret's voice suddenly crackled over the intercom.

"Control deck, aye," replied Connel. "Ready to blast?"

"All set!"

"Give me a ten-second burst on the starboard steering rockets," ordered Connel, gripping the steering vane control tightly.

"Coming up!"

There was a sudden, jolting blast from the stern and Connel and Hemmingwell hung on grimly as the mighty ship turned in space. Watching the control panel instruments carefully, Connel slammed home the switch that opened the powerful nose braking rockets and brought the ship to a dead stop in space.

"On course, Professor, ready to fire!" Connel announced triumphantly, and Hemmingwell took his station before the giant projectile control board.

"Stand by to fire one!" said the professor, making a minute adjustment on the panel. Behind him, Connel unconsciously crossed his fingers.

"Fire one!" shouted Hemmingwell.

Connel pressed a red button on the panel and waited, holding his breath. There was a distinct hissing and then the great ship lurched slightly. On the teleceiver overhead a white flash appeared, streaked across the screen, and then disappeared in the darkness of space.

"Fire two!"

Again there was a hissing sound and another white burst of light faded into the millions of other pinpoints of lights in the black void.

Over and over again, at one-minute intervals, the projectiles were fired, until all twelve of the firing chambers had discharged their fire-tailed missiles.

The professor sat back and smiled weakly at Connel. The gruff major winked encouragingly and they both turned to watch the teleceiver screen anxiously. The gyros on each projectile had been preset for a circular flight of fifteen minutes' duration. Soon they would be returning and the delicate job of bringing them safely aboard would begin.

"Here comes number one," shouted Connel, as a small pinpoint of light appeared on the screen.

"I'm ready!" said the professor. He watched the teleceiver screen carefully, made a minute adjustment of the dial controlling the directional beam emitted by the ring in the number-one firing chamber, and at the last possible moment, snapped the remote-control switch that cut the power in the approaching test projectile. It hung dead in space, immediately over the chamber. Gently the professor increased the power of the electro-magnetic ring and pulled the projectile back into the chamber as easily as slipping a hand in a glove.

"Success!" Connel shouted. "Professor, you've done it!"

"Congratulations, sir," Dave Barret called over the intercom from the power deck.

"Here comes number two," said Professor Hemmingwell excitedly, and began to repeat the process to draw the approaching projectiles back into the ship.

One after another, five projectiles were taken aboard successfully. Then, as he worked on the sixth, the professor began to frown. He rechecked his instruments and then shook his head, obviously disturbed.

"What's the trouble?" growled Connel, noticing Hemmingwell's growing nervousness.

"The homing ring on number six tube isn't working properly," replied Hemmingwell. "I can't control the projectile."

"Any idea what's wrong?" the Solar Guard officer asked.

"The settings on the ring must be wrong." The professor picked up the intercom mike. "Dave," he called, "check in!"

"Yes, sir?" replied Barret immediately.

"Did you check the settings on all the rings in the firing chambers?"

"Yes, sir," reported Barret. "They looked O.K. to me. Why don't you check with Connel? He supervised their installation."

"That's true," said the major. "I'll go outside and look them over."

Connel turned on his heel and hurried to the air-lock chamber. Moving with amazing speed for a big man, he donned the space suit in the chamber while the pressure was being equalized. As soon as the air-lock portal opened, he scrambled out on the hull and made his way forward to the bulging firing chambers. Stooping over the empty tube of number six, he examined the ring carefully and began to frown. Moving on to number seven, his frown deepened. By the time he checked the rings of eight and nine, his face was a grim mask of anger.

"Professor," he called into his helmet microphone, "check in."

"Yes, Major," replied Hemmingwell from the control deck. "Have you found the trouble?"

"I sure have," Connel growled. "It's sabotage! And now I think I know who—"

Connel never finished. There was a sudden burst of power from the great ship and the officer was hurled into space.

"Major!" cried Hemmingwell. "Barret! What have you done? Connel is outside!"

"I couldn't help it, Professor," replied Barret from the power deck. "My hand slipped and—"

"Don't talk!" shouted Hemmingwell. "Stop the ship!"

"I can't! The control is jammed!"

As the ship surged through space and the professor and Barret yelled at each other over the intercom, three Space Cadets rose from their hiding place in the hold of the ship.

Tom Corbett nudged Roger and Astro. "You hear that?" he said grimly.

"Yeah!" replied Roger.

"Let's go!" growled Astro.

Without another word, they opened the hatch and made their way quickly through the rocketing ship, each going to their separate stations, according to the prearranged plan. Roger climbed up to the radar bridge, Tom entered the control deck, and Astro burst into the power deck.

"You!" Barret cried out, his eyes wide with sudden fear as the huge Venusian advanced on him menacingly.

"Get away from those controls," growled the big cadet. "If you don't, so help me, I'll break you in two!"

Barret backed away, his face white, hands pawing the air frantically as if he were trying to push the big cadet back.

"Get over there," said Astro. "Sit down and keep your mouth shut!"

On the control deck, Tom was strapping himself into the pilot's chair and calling frantically into the intercom, "Give me a course, Roger!"

"One-seventy-degree turn to starboard," replied Roger, "and full ahead! I've got the major on my scanner."

"Pour on the power, Astro!" shouted Tom, gripping the controls firmly.

As the mighty ship blasted in a long, sweeping arc, Professor Hemmingwell sat numbly in his chair, aware only that the three cadets were taking the vessel back into the area where the remaining projectiles, completely out of control, were buzzing around in space like maddened hornets.