To the world at large, of course, it was just another day. A different sort entirely at different places on the great, round, rolling Earth, but nothing out of the ordinary. It was Tuesday on one side of the Date Line and Monday on the other. It was so-and-so's wedding anniversary and so-and-so's birthday and another so-and-so would get out of jail today. It was warm, it was cool, it was fair, it was cloudy. One looked forward to the future with confidence, with hope, with uneasiness or with terror according to one's temperament and one's geographical location and past history. To most of the human race this was nothing whatever but just another day.

But to Joe Kenmore it was a most particular day indeed. Here, it was the gray hour just before sunrise and already there were hints of reddish colorings in the sky. It was chilly, and somehow the world seemed still and breathless. To Joe, the feeling of tensity marked this morning off from all the other mornings of his experience.

He got up and began to dress, in Major Holt's quarters back of that giant steel half-globe called the Shed, near the town of Bootstrap. He felt queer because he felt so much as usual. By all the rules, he should have experienced a splendid, noble resolution and a fiery exaltation, and perhaps even an admirable sensation of humility and unworthiness to accomplish what was expected of him today. And, deep enough inside, he felt suitable emotion. But it happened that he couldn't take time to feel things adequately today.

He was much more aware that he wanted some coffee rather badly, and that he hoped everything would go all right. He looked out of the windows at empty, dreary desert under the dawn sky. Today was the day he'd be leaving on a rather important journey. He hoped that Haney and the Chief and Mike weren't nervous. He also hoped that nobody had gotten at the fuel for the pushpots, and that the slide-rule crew that had calculated everything hadn't made any mistakes. He was also bothered about the steering-rocket fuel, and he was uncomfortable about the business of releasing the spaceship from the launching cage. There was, too, cause for worry in the take-off rockets—if the tube linings had shrunk there would be some rather gruesome consequences—and there could always be last-minute orders from Washington to delay or even cancel everything.

In short, his mind was full of strictly practical details. He didn't have time to feel noble aspirations or sensations of high destiny. He had a very tricky and exacting job ahead of him.

The sky was growing lighter outside. Stars faded in a paling blue and the desert showed faint colorings. He tied his necktie. A deep-toned keening set up off to the southward, over the sere and dreary landscape. It was a faraway noise, something like the lament of a mountain-sized calf bleating for its mother. Joe took a deep breath. He looked, but saw nothing. The noise, though, told him that there'd been no cancellation of orders so far. He mentally uncrossed one pair of fingers. He couldn't possibly cross fingers against all foreseeable disasters. There weren't enough fingers—or toes either. But it was good that so far the schedule held.

He went downstairs. Major Holt was pacing up and down the living room of his quarters. Electric lights burned, but already the windows were brightening. Joe straightened up and tried to look casual. Strictly speaking, Major Holt was a family friend who happened also to be security officer here, in charge of protecting what went on in the giant construction Shed. He'd had a sufficiently difficult time of it in the past, and the difficulties might keep on in the future. He was also the ranking officer here and consequently the immediate boss of Joe's enterprise. Today's affair was still highly precarious. The whole thing was controversial and uncertain and might spoil the career of somebody with stars on his collar if it should fail. So nobody in the high brass wanted the responsibility. If everything went well, somebody suitable would take the credit and the bows. Meanwhile Major Holt was boss by default.

He looked sharply at Joe. "Morning."

"Good morning, sir," said Joe. Major Holt's daughter Sally had a sort of understanding with Joe, but the major hadn't the knack of cordiality, and nobody felt too much at ease with him. Besides, Joe was wearing a uniform for the first time this morning. There were only eight such uniforms in the world, so far. It was black whipcord, with an Eisenhower jacket, narrow silver braid on the collar and cuffs, and a silver rocket for a badge where a plane pilot wears his wings. It was strictly practical. Against accidental catchings in machinery, the trousers were narrow and tucked into ten-inch soft leather boots, and the wide leather belt had flat loops for the attachment of special equipment. Its width was a brace against the strains of acceleration. Sally had had much to do with its design.

But it hadn't yet been decided by the Pentagon whether the Space Exploration Project would be taken over by the Army or the Navy or the Air Corps, so Joe wore no insignia of rank. Technically he was still a civilian.

The deep-toned noise to the south had become a howl, sweeping closer and trailed by other howlings.

"The pushpots are on the way over, as you can hear," said the major detachedly, in the curious light of daybreak and electric bulbs together. "Your crew is up and about. So far there seems to be no hitch. You're feeling all right for the attempt today?"

"If you want the truth, sir, I'd feel better with about ten years' practical experience behind me. But my gang and myself—we've had all the training we can get without an actual take-off. We're the best-trained crew to try it. I think we'll manage."

"I see," said the major. "You'll do your best."

"We may have to do better than that," admitted Joe wrily.

"True enough. You may." The major paused. "You're well aware that there are—ah—people who do not altogether like the idea of the United States possessing an artificial satellite of Earth."

"I ought to know it," admitted Joe.

The Earth's second, man-constructed moon—out in space for just six weeks now—didn't seem nowadays like the bitterly contested achievement it actually was. From Earth it was merely a tiny speck of light in the sky, identifiable for what it was only because it moved so swiftly and serenely from the sunset toward the east, or from night's darkness into the dawn-light. But it had been fought bitterly before it was launched. It was first proposed to the United Nations, but even discussion in the Council was vetoed. So the United States had built it alone. Yet the nations which objected to it as an international project liked it even less as a national one, and they'd done what they could to wreck it.

The building of the great steel hull now out there in emptiness had been fought more bitterly, by more ruthless and more highly trained saboteurs, than any other enterprise in history. There'd been two attempts to blast it with atomic bombs. But it was high aloft, rolling grandly around the Earth, so close to its primary that its period was little more than four hours; and it rose in the west and set in the east six times a day.

Today Joe would try to get a supply ship up to it, a very small rocket-driven cargo ship named Pelican One. The crew of the Platform needed food and air and water—and especially the means of self-defense. Today's take-off would be the first attempt at a rocket-lift to space.

"The enemies of the Platform haven't given up," said the major formidably. "And they used spectroscopes on the Platform's rocket fumes. Apparently they've been able to duplicate our fuel."

Joe nodded.

Major Holt went on: "For more than a month Military Intelligence has been aware that rockets were under construction behind the Iron Curtain. They will be guided missiles, and they will carry atom bomb heads. One or more may be finished any day. When they're finished, you can bet that they'll be used against the Platform. And you will carry up the first arms for the Platform. Your ship carries half a dozen long-range interceptor rockets to handle any attack from Earth. It's vitally important for them to be delivered."

"They'll attack the Platform?" demanded Joe angrily. "That's war!"

"Not if they deny guilt," said the major ironically, "and if we have nothing to gain by war. The Platform is intended to defend the peace of the world. If it is destroyed, we won't defend the peace of the world by going to war over it. But while the Platform can defend itself, it is not likely that anyone will dare to make war. So you have a very worthwhile mission. I suggest that you have breakfast and report to the Shed. I'm on my way there now."

Joe said, "Yes, sir."

The major started for the door. Then he stopped. He hesitated, and said abruptly, "If my security measures have failed, Joe, you'll be killed. If there has been sabotage or carelessness, it will be my fault."

"I'm sure, sir, that everything anybody could do—"

"Everything anybody can do to destroy you has been done," said the major grimly. "Not only sabotage, Joe, but blunders and mistakes and stupidities. That always happens. But—I've done my best. I suspect I'm asking your forgiveness if my best hasn't been good enough."

Then, before Joe could reply, the major went hurriedly away.

Joe frowned for a moment. It occurred to him that it must be pretty tough to be responsible for the things that other men's lives depend on—when you can't share their danger. But just then the smell of coffee reached his nostrils. He trailed the scent. There was a coffeepot steaming on the table in the dining-room. There was a note on a plate.

Joe was relieved. Sally Holt had been somewhere around underfoot all his life. She was a swell girl, but he was grateful that he didn't have to talk to her just now.

He poured coffee and looked at his watch. He went to the window. The faraway howling was much nearer, and dawn had definitely arrived. Small cloudlets in a pale blue sky were tinted pinkish by the rising sun. Patches of yucca and mesquite and sage out beyond the officers' quarters area stretched away to a far-off horizon. They were now visibly different in color from the red-yellow earth between them, and cast long, streaky shadows. The cause of the howling was still invisible.

But Joe cared nothing for that. He stared skyward, searching. And he saw what he looked for.

There was a small bright sliver of sunlight high aloft. It moved slowly toward the east. It showed the unmistakable glint of sunshine upon polished steel. It was the artificial satellite—a huge steel hull—which had been built in the gigantic Shed from whose shadow Joe looked upward. It was the size of an ocean liner, and six weeks since some hundreds of pushpots, all straining at once, had gotten it out of the Shed and panted toward the sky with it. They'd gotten it twelve miles high and speeding eastward at the ultimate speed they could manage. They'd fired jato rockets, all at once, and so pushed its speed up to the preposterous. Then they'd dropped away and the giant steel thing had fired its own rockets—which made mile-long flames—and swept on out to emptiness. Before its rockets were consumed it was in an orbit 4,000 miles above the Earth's surface, and it hurtled through space at something over 12,000 miles an hour. It circled the Earth in exactly four hours, fourteen minutes, and twenty-two seconds. And it would continue its circling forever, needing no fuel and never descending. It was a second moon for the planet Earth.

But it could be destroyed.

Joe watched hungrily as it went on to meet the sun. Smoothly, unhurriedly, serenely, the remote and twinkling speck floated on out of sight. And then Joe went back to the table and ate his breakfast quickly. He wolfed it. He had an appointment to meet that minute speck some 4,000 miles out in space. His appointment was for a very few hours hence.

He'd been training for just this morning's effort since before the Platform's launching. There was a great box swinging in twenty-foot gimbal rings over in the Shed. There were motors and projectors and over two thousand vacuum tubes, relays and electronic units. It was a space flight simulator—a descendant of the Link trainer which once taught plane pilots how to fly. But this offered the problems and the sensations of rocketship control, and for many hours every day Joe and the three members of his crew had labored in it. The simulator duplicated every sight and sound and feeling—all but heavy acceleration—to be experienced in the take-off of a rocketship to space. The similitude of flight was utterly convincing. Sometimes it was appallingly so when emergencies and catastrophes and calamities were staged in horrifying detail for them to learn to respond to. In six weeks they'd learned how to handle a spaceship so far as anybody could learn on solid ground—if the simulator was correctly built. Nobody could be sure about that. But it was the best training that could be devised.

In minutes Joe had finished the coffee and was out of Major Holt's quarters and headed for the Shed's nearest entrance. The Shed was a gigantic metal structure rising out of sheer flat desert. There were hills to the westward, but only arid plain to the east and south and north. There was but one town in hundreds of miles and that was Bootstrap, built to house the workmen who'd built the Platform and the still invisible, ferociously howling pushpots and now the small supply ships, the first of which was to make its first trip today.

The Shed seemed very near because of its monstrous size. When he was actually at the base of its wall, it seemed to fill half the firmament and more than half the horizon. He went in, and felt self-conscious when the guard's eyes fell on his uniform. There was a tiny vestibule. Then he was in the Shed itself, and it was enormous.

There were acres of wood-block flooring. There was a vast, steel-girdered arching roof which was fifty stories high in the center. All this size had been needed when the Space Platform was being built. Men on the far side were merely specks, and the rows of windows to admit light usually did no more than make a gray twilight inside. But there was light enough today. To the east the Shed's wall was split from top to bottom. A colossal triangular gore had been loosened and thrust out and rolled aside, and a doorway a hundred and fifty feet wide let in the sunshine. Through it, Joe could see the fiery red ball which was the sun just leaving the horizon.

But there was something more urgent for him to look at. Pelican One had been moved into its launching cage. Only Joe, perhaps, would really have recognized it. Actually it was a streamlined hull of steel, eighty feet long by twenty in diameter. There were stubby metal fins—useless in space, and even on take-off, but essential for the planned method of landing on its return. There were thick quartz ports in the bow-section. But its form was completely concealed now by the attached, exterior take-off rockets. It had been shifted into the huge cradle of steel beams from which it was to be launched. Men swarmed about it and over it, in and out of the launching cage, checking and rechecking every possible thing that could make for the success of its flight to space.

The other three crew-members were ready—Haney and Chief Bender and Mike Scandia. They were especially entitled to be the crew of this first supply ship. When the Platform was being built, its pilot-gyros had been built by a precision tool firm owned by Joe's father. He'd gone by plane with the infinitely precise apparatus to Bootstrap, to deliver and install it in the Platform. And the plane was sabotaged, and the gyros were ruined. They'd consumed four months in the building, and four months more for balancing with absolute no-tolerance accuracy. The Platform couldn't wait so long for duplicates. So Joe had improvised a method of repair. And with Haney to devise special machine-tool setups and the Chief to use fanatically fine workmanship, and Mike and Joe aiding according to their gifts, they'd rebuilt the apparatus in an impossibly short time. The original notion was Joe's, but he couldn't have done the job without the others.

And there had been other, incidental triumphs by the team of four. They were not the only ones who worked feverishly for the glory of having helped to build the Earth's first artificial moon, but they had accomplished more than most. Joe had even been appointed to be an alternate member of the Platform's crew. But the man he was to have substituted for recovered from an illness, and Joe was left behind at the Platform's launching. But all of them had rated some reward, and it was to serve in the small ships that would supply the man-made satellite.

Now they were ready to begin. The Chief grinned exuberantly as Joe ducked through the bars of the launching cage and approached the ship. He was a Mohawk Indian—one of that tribe which for two generations had supplied steel workers to every bridge and dam and skyscraper job on the continent. He was brown and bulky and explosive. Haney looked tense and strained. He was tall and lean and spare, and a good man in any sort of trouble. Mike blazed excitement. Mike was forty-one inches high and he was full-grown. He had worked on the Platform, bucking rivets and making welds and inspections in places too small for a normal-sized man to reach. He frantically resented any concessions to his size and he was as good a man as any. He simply was the small, economy size.

"Hiya, Joe," boomed the Chief. "All set? Had breakfast?"

Joe nodded. He began to ask anxious questions. About steering-rocket fuel and the launching cage release and the take-off rockets and the reduction valve from the air tanks—he'd thought of that on the way over—and the short wave and loran and radar. Haney nodded to some questions. Mike said briskly, "I checked" to others.

The Chief grunted amiably, "Look, Joe! We checked everything last night. We checked it again this morning. I even caught Mike polishing the ejection seats, because there wasn't anything else to make sure of!"

Joe managed a smile. The ejection seats were assuredly the most unlikely of all devices to be useful today. They were supposedly life-saving devices. If the ship came a cropper on take-off, the four of them were supposed to use ejection-seats like those supplied to jet pilots. They would be thrown clear of the ship and ribbon-parachutes might open and might let them land alive. But it wasn't likely. Joe had objected to their presence. If a feather dropped to Earth from a height of 600 miles, it would be falling so fast when it hit the atmosphere that it would heat up and burn to ashes from pure air-friction. It wasn't likely that they could get out of the ship if anything went wrong.

Somebody marched stiffly toward the four of them. Joe's expression grew rueful. The Space Project was neither Army nor Navy nor Air Corps, but something that so far was its own individual self. But the man marching toward Joe was Lieutenant Commander Brown, strictly Navy, assigned to the Shed as an observer. And there were some times when he baffled Joe. Like now.

He halted, and looked as if he expected Joe to salute. Joe didn't.

Lieutenant Commander Brown said, formally: "I would like to offer my best wishes for your trip, Mr. Kenmore."

"Thanks," said Joe.

Brown smiled distantly. "You understand, of course, that I consider navigation essentially a naval function, and it does seem to me that any ship, including a spaceship, should be manned by naval personnel. But I assuredly wish you good fortune."

"Thanks," said Joe again.

Brown shook hands, then stalked off.

Haney rumbled in his throat. "How come, Joe, he doesn't wish all of us good luck?"

"He does," said Joe. "But his mind's in uniform too. He's been trained that way. I'd like to make a bet that we have him as a passenger out to the Platform some day."

"Heaven forbid!" growled Haney.

There was an outrageous tumult outside the wide-open gap in the Shed's wall. Something went shrieking by the doorway. It looked like the magnified top half of a loaf of baker's bread, painted gray and equipped with an air-scoop in front and a plastic bubble for a pilot. It howled like a lost baby dragon, its flat underside tilted up and up until it was almost vertical. It had no wings, but a blue-white flame spurted out of its rear, wobbling from side to side for reasons best known to itself. It was a pushpot, which could not possibly be called a jet plane because it could not possibly fly. Only it did. It settled down on its flame-spouting tail, and the sparse vegetation burst into smoky flame and shriveled, and the thing—still shrieking like a fog-horn in a tunnel—flopped flat forward with a resounding clank! It was abruptly silent.

But the total noise was not lessened. Another pushpot came soaring wildly into view, making hysterical outcries. It touched and banged violently to earth. Others appeared in the air beyond the construction Shed. One flopped so hard on landing that its tail rose in the air and it attempted a somersault. It made ten times more noise than before—the flame from its tail making wild gyrations—and flopped back again with a crash. Two others rolled over on their sides after touching ground. One ended up on its back like a tumble-bug, wriggling.

They seemed to land by hundreds, but their number was actually in dozens. It was not until the last one was down that Joe could make himself heard. The pushpots were jet motors in frames and metal skin, with built-in jato rocket tubes besides their engines. On the ground they were quite helpless. In the air they were unbelievably clumsy. They were actually balanced and steered by vanes in the blasts of their jets, and they combined the absolute maximum of sheer thrust with the irreducible minimum of flyability.

Crane-trucks went out to pick them up. Joe said anxiously, "We'd better check our flight plan again. We have to know it absolutely!"

He headed across the floor to the flight data board. He passed the hull of another ship like his own, which was near completion, and the bare skeletons of two others which needed a lot of work yet. They'd been begun at distant plants and then hauled here on monstrous trailers for completion. The wooden mockup of the design for all the ships—in which every possible arrangement of instruments and machinery had been tested out—lay neglected by the Shed wall.

The four stood before the flight data board. It listed the readings every instrument should show during every instant of the flight. The readings had been calculated with infinite care, and Joe and the others needed to know them rather better than they knew their multiplication tables. Once they started out, they wouldn't have time to wonder if everything was right for the time and place. They needed to know.

They stood there, soaking up the information the board contained, forming mental pictures of it, making as sure as possible that any one of them would spot anything wrong the instant it showed up, and would instantly know what had to be done about it.

A gigantic crane-truck came in through the wide doorway. It dangled a pushpot. It rolled over to the launching cage in which the spaceship lay and set the unwieldy metal object against that cage. There was a clank as the pushpot caught hold of the magnetic grapples. The crane went out again, passing a second crane carrying a second pushpot. The second beetle-like thing was presented to the cage. It stuck fast. The crane went out for more.

Major Holt came across the floor of the Shed. It took him a long time to walk the distance from the Security offices to the launching cage. When he got there, he looked impatiently around. His daughter Sally came out of nowhere and blew her nose as if she'd been crying, and pointed to the data board. The major shrugged his shoulders and looked uneasily at her. She regarded him with some defiance. The major spoke to her sternly. They waited.

The cranes brought in more pushpots and set them up against the steel launching cage. The ship had been nearly hidden before by the rocket tubes fastened outside its hull. It went completely out of sight behind the metal monsters banked about it.

The major looked at his watch and the group about the data board. They moved away from it and back toward the ship. Joe saw the major and swerved over to him.

"I have brought you," said the major in an official voice, "the invoice of your cargo. You will deliver the invoice with the cargo and bring back proper receipts."

"I hope," said Joe.

"We hope!" said Sally in a strained tone. "Good luck, Joe!"

"Thanks."

"There is not much to say to you," said the major without visible emotion. "Of course the next crew will start its training immediately, but it may be a month before another ship can take off. It is extremely desirable that you reach the Platform today."

"Yes, sir," said Joe wrily. "I have even a personal motive to get there. If I don't, I break my neck."

The major ignored the comment. He shook hands formally and marched away. Sally smiled up at Joe, but her eyes were suddenly full of tears.

"I—do hope everything goes all right, Joe," she said unsteadily. "I—I'll be praying for you."

"I can use some of that, too," admitted Joe.

She looked at her hand. Joe's ring was on her finger—wrapped with string on the inside of the band to make it fit. Then she looked up again and was crying unashamedly.

"I—will," she repeated. Then she said fiercely, "I don't care if somebody's looking, Joe. It's time for you to go in the ship."

He kissed her, and turned and went quickly to the peculiar mass of clustered pushpots, touching and almost overlapping each other.

He ducked under and looked back. Sally waved. He waved back. Then he climbed up the ladder into Pelican One's cabin. Somebody pulled the ladder away and scuttled out of the cage.

The others were in their places. Joe slowly closed the door from the cabin to the outer world. There was suddenly a cushioned silence about him. Out the quartz-glass ports he could see ahead, out the end of the cage through the monstrous doorway to the desert beyond. Overhead he could see the dark, girder-lined roof of the Shed. On either side, though, he could see only the scratched, dented, flat undersides of the pushpots ready to lift the ship upward.

"You can start on the pushpot motors, Haney," he said curtly.

Joe moved to his own, the pilot's seat. Haney pushed a button. Through the fabric of the ship came the muted uproar of a pushpot engine starting. Haney pushed another button. Another. Another. More jet engines bellowed. The tumult in the Shed would be past endurance, now.

Joe strapped himself into his seat. He made sure that the Chief at the steering-rocket manual controls was fastened properly, and Mike at the radio panel was firmly belted past the chance of injury.

Haney said with enormous calm, "All pushpot motors running, Joe."

"Steering rockets ready," the Chief reported.

"Radio operating," came from Mike. "Communications room all set."

Joe reached to the maneuver controls. He should have been sweating. His hands, perhaps, should have quivered with tension. But he was too much worried about too many things. Nobody can strike an attitude or go into a blue funk while they are worrying about things to be done. Joe heard the small gyro motors as their speed went up. A hum and a whine and then a shrill whistle which went up in pitch until it wasn't anything at all. He frowned anxiously and said to Haney, "I'm taking over the pushpots."

Haney nodded. Joe took the over-all control. The roar of engines outside grew loud on the right-hand side, and died down. It grew thunderous to the left, and dwindled. The ones ahead pushed. Then the ones behind. Joe nodded and wet his lips. He said: "Here we go."

There was no more ceremony than that. The noise of the jet motors outside rose to a thunderous volume which came even through the little ship's insulated hull. Then it grew louder, and louder still, and Joe stirred the controls by ever so tiny a movement.

Suddenly the ship did not feel solid. It stirred a little. Joe held his breath and cracked the over-all control of the pushpots' speed a tiny trace further. The ship wobbled a little. Out the quartz-glass windows, the great door seemed to descend. In reality the clustered pushpots and the launching cage rose some thirty feet from the Shed floor and hovered there uncertainly. Joe shifted the lever that governed the vanes in the jet motor blasts. Ship and cage and pushpots, all together, wavered toward the doorway. They passed out of it, rocking a little and pitching a little and wallowing a little. As a flying device, the combination was a howling tumult and a horror. It was an aviation designer's nightmare. It was a bad dream by any standard.

But it wasn't meant as a way to fly from one place to another on Earth. It was the first booster stage of a three-stage rocket aimed at outer space. It looked rather like—well—if a swarm of bumblebees clung fiercely to a wire-gauze cage in which lay a silver minnow wrapped in match-sticks; and if the bees buzzed furiously and lifted it in a straining, clumsy, and altogether unreasonable manner; and if the appearance and the noise together were multiplied a good many thousands of times—why—it would present a great similarity to the take-off of the spaceship under Joe's command. Nothing like it could be graceful or neatly controllable or even very speedy in the thick atmosphere near the ground. But higher, it would be another matter.

It was another matter. Once clear of the Shed, and with flat, sere desert ahead to the very horizon, Joe threw on full power to the pushpot motors. The clumsy-seeming aggregation of grotesque objects began to climb. Ungainly it was, and clumsy it was, but it went upward at a rate a jet-fighter might have trouble matching. It wobbled, and it swung around and around, and it tipped crazily, the whole aggregation of jet motors and cage and burden of spaceship as a unit. But it rose!

The ground dropped so swiftly that even the Shed seemed to shrivel like a pricked balloon. The horizon retreated as if a carpet were hastily unrolled by magic. The barometric pressure needles turned.

"Communications says our rate-of-climb is 4,000 feet a minute and going up fast," Mike announced. "It's five.... We're at 17,000 feet ... 18,000. We should get some eastward velocity at 32,000 feet. Our height is now 21,000 feet...."

There was no change in the feel of things inside the ship, of course. Sealed against the vacuum of space, barometric pressure outside made no difference. Height had no effect on the air inside the ship.

At 25,000 feet the Chief said suddenly: "We're pointed due east, Joe. Freeze it?"

"Right," said Joe. "Freeze it."

The Chief threw a lever. The gyros were running at full operating speed. By engaging them, the Chief had all their stored-up kinetic energy available to resist any change of direction the pushpots might produce by minor variations in their thrusts. Haney brooded over the reports from the individual engines outside. He made minute adjustments to keep them balanced. Mike uttered curt comments into the communicator from time to time.

At 33,000 feet there was a momentary sensation as if the ship were tilted sharply. It wasn't. The instruments denied any change from level rise. The upward-soaring complex of flying things had simply risen into a jet-stream, one of those wildly rushing wind-floods of the upper atmosphere.

"Eastern velocity four hundred," said Mike from the communicator. "Now four-twenty-five.... Four-forty."

There was a 300-mile-an-hour wind behind them. A tail-wind, west to east. The pushpots struggled now to get the maximum possible forward thrust before they rose out of that east-bound hurricane. They added a fierce push to eastward to their upward thrust. Mike's cracked voice reported 500 miles an hour. Presently it was 600.

At 40,000 feet they were moving eastward at 680 miles an hour. A jet-motor cannot be rated except indirectly, but there was over 200,000 horsepower at work to raise the spacecraft and build up the highest possible forward speed. It couldn't be kept up, of course. The pushpots couldn't carry enough fuel.

But they reached 55,000 feet, which is where space begins for humankind. A man exposed to emptiness at that height will die just as quickly as anywhere between the stars. But it wasn't quite empty space for the pushpots. There was still a very, very little air. The pushpots could still thrust upward. Feebly, now, but they still thrust.

Mike said: "Communications says get set to fire jatos, Joe."

"Right!" he replied. "Set yourselves."

Mike flung a switch, and a voice began to chatter behind Joe's head. It was the voice from the communications-room atop the Shed, now far below and far behind. Mike settled himself in the tiny acceleration-chair built for him. The Chief squirmed to comfort in his seat. Haney took his hands from the equalizing adjustments he had to make so that Joe's use of the controls would be exact, regardless of moment-to-moment differences in the thrust of the various jets.

"We've got a yaw right," said the Chief sharply. "Hold it, Joe!"

Joe waited for small quivering needles to return to their proper registrations.

"Back and steady," said the Chief a moment later. "Okay!"

The tinny voice behind Joe now spoke precisely. Mike had listened to it while the work of take-off could be divided, so that Joe would not be distracted. Now Joe had to control everything at once.

The roar of the pushpots outside the ship had long since lost the volume and timbre of normal atmosphere. Not much sound could be transmitted by the near-vacuum outside. But the jet motors did roar, and the sound which was not sound at such a height was transmitted by the metal cage as so much pure vibration. The walls and hull of the spaceship picked up a crawling, quivering pulsation and turned it into sound. Standing waves set up and dissolved and moved erratically in the air of the cabin. Joe's eardrums were strangely affected. Now one ear seemed muted by a temporary difference of air pressure where a standing wave lingered for a second or two. Then the other eardrum itched. There were creeping sensations as of things touching one and quickly moving away.

Joe swung a microphone into place before his mouth.

"All set," he said evenly. "Brief me."

The tinny voice said:

"You are at 65,000 feet. Your curve of rate-of-climb is flattening out. You are now rising at near-maximum speed, and not much more forward velocity can be anticipated. You have an air-speed relative to surface of six-nine-two miles per hour. The rotational speed of Earth at this latitude is seven-seven-eight. You have, then, a total orbital speed of one-four-seven-oh miles per hour, or nearly twelve per cent of your needed final velocity. Since you will take off laterally and practically without air resistance, a margin of safety remains. You are authorized to blast."

Joe said:

"Ten seconds. Nine ... eight ... seven ... six ... five ... four ... three ... two ... one...."

He stabbed the master jato switch. And a monstrous jato rocket, built into each and every one of the pushpots outside, flared chemical fumes in a simultaneous, gigantic thrust. A small wire-wound jato for jet-assisted-take-off will weigh a hundred and forty pounds and deliver a thousand pounds of thrust for fourteen seconds. And that is for rockets using nonpoisonous compounds. The jatos of the pushpots used the beryllium-fluorine fuel that had lifted the Platform and that filled the take-off rockets of Joe's ship. These jatos gave the pushpots themselves an acceleration of ten gravities, but it had to be shared with the cage and the ship. Still....

Joe felt himself slammed back into his seat with irresistible, overwhelming force. The vibration from the jets had been bad. Now he didn't notice it. He didn't notice much of anything but the horrible sensations of six-gravity acceleration.

It was not exactly pain. It was a feeling as if a completely intolerable and unbearable pressure pushed at him. Not only on the outside, like a blow, but inside too, like nothing else imaginable. Not only his chest pressed upon his lungs, but his lungs strained toward his backbone. Not only the flesh of his thighs tugged to flatten itself against his acceleration-chair, but the blood in his legs tried to flow into and burst the blood-vessels in the back of his legs.

The six-gravity acceleration seemed to endure for centuries. Actually, it lasted for fourteen seconds. In that time it increased the speed of the little ship by rather more than half a mile per second, something over 1,800 miles per hour. Before, the ship had possessed an orbital speed of a shade over 1,470 miles an hour. After the jato thrust, it was traveling nearly 3,400 miles per hour. It needed to travel something over 12,000 miles per hour to reach the artificial satellite of Earth.

The intolerable thrust ended abruptly. Joe gasped. But he could allow himself only a shake of the head to clear his brain. He jammed down the take-off rocket firing button. There was a monstrous noise and a mighty surging, and Haney panted, "Clear of cage...."

And then they were pressed fiercely against their acceleration chairs again. The ship was no longer in its launching cage. It was no longer upheld by pushpots. It was free, with its take-off rockets flaming. It plunged on up and out. But the acceleration was less. Nobody can stand six gravities for long. Anybody can take three—for a while.

Joe's body resisted movement with a weight of four hundred and fifty pounds, instead of a third as much for normal. His heart had to pump against three times the normal resistance of gravity. His chest felt as if it had a leaden weight on it. His tongue tried to crowd the back of his mouth and strangle him. The sensation was that of a nightmare of impossible duration. It was possible to move and possible to see. One could breathe, with difficulty, and with titanic effort one could speak. But there was the same feeling of stifling resistance to every movement that comes in nightmares.

But Joe managed to keep his eyes focused. The dials of the instruments said that everything was right. The tinny voice behind his head, its timbre changed by the weighting of its diaphragm, said: "All readings check within accuracy of instruments. Good work!"

Joe moved his eyes to a quartz window. The sky was black. But there were stars. Bright stars against a black background. At the same instant he saw the bright white disks of sunshine that came in the cabin portholes. Stars and sunshine together. And the sunshine was the sunshine of space. Even with the polarizers cutting off some of the glare it was unbearably bright and hot beyond conception. He smelled overheated paint, where the sunlight smote on a metal bulkhead. Stars and super-hot sunshine together....

It was necessary to pant for breath, and his heart pounded horribly and his eyes tried to go out of focus, but Joe Kenmore strained in his acceleration-chair and managed to laugh a little.

"We did it!" he panted. "In case you didn't notice, we're out of—the atmosphere and—out in space! We're—headed to join the Space Platform!"

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