The world turned over on its axis with unfailing regularity, and nights followed mornings and mornings followed nights according to well-established precedent. One man turned up in Bootstrap with radiation burns, but he had not offered himself for check over at the hospital. He was found dead in his lodging. Since nobody else appeared to have suffered any burns at all, it was assumed that he was the messenger who had brought the radioactive cobalt to Braun, who also had been doomed by possession of the deadly stuff, but who had broken the chain of fatality by not dumping it free into the air of the Shed. Under the circumstances, then, three-shift work on the Platform was resumed, and three times in each twenty-four hours fleets of busses rolled out of Bootstrap carrying men to work in the Shed, and rolled back again loaded with men who had just stopped working there.

Trucks carried materials to the Shed, and swing-up doors opened in the great dome’s eastern wall, and the trucks went in and unloaded. Then the trucks went out of the same doors and trundled back for more materials. In the Shed, shining plates of metal swung aloft, and welding torches glittered in the maze of joists and upright pipes that still covered the monster shape. Each day it was a little more nearly complete. In a separate, guarded workshop by a sidewall, the Chief and Haney and Mike the midget labored mightily to accomplish the preposterous. They grew lean and red-eyed from fatigue, and short of temper and ever more fanatical—and security men moved about in seeming uselessness but never-ceasing vigilance.

There were changes, though. The assembly line of pushpots grew shorter, and the remaining monstrosities around the sidewall were plainly near to completion. There came a day, indeed, when only five ungainly objects remained on that line, and even they were completely plated in and needed only a finishing touch. It was at this time that more crates and parcels arrived from the Kenmore Precision Tool plant, and Joe dropped his schoolroomlike instruction course in space flight for work of greater immediate need. He and his allies worked twice around the clock to assemble the replaced parts with the repaired elements of the pilot gyros. They grew groggy from the desperate need both for speed and for absolute accuracy, but they put the complex device together, and adjusted it, and surveyed the result through red-rimmed eyes, and were too weary to rejoice.

Then Joe threw a switch and the reconstituted pilot gyro assembly began to hum quietly, and the humming rose to a whine, and the whine went deliberately up the scale until it ceased to be audible at all. Presently a dial announced the impossible, and they gazed at a device that seemed to be doing nothing whatever. The gyros appeared quite motionless. They spun with such incredible precision that it was not possible to detect that they moved a hairbreadth. And the whole complex device looked very simple and useless.

But the four of them gazed at it—now that it worked—with a sudden passionate satisfaction. Joe moved a control, and the axis of the device moved smoothly to a new place and stayed there. He moved the control again, and it moved to another position and stayed there. And to another and another and another.

Then the Chief took Joe’s place, and under his hand the seemingly static disks—which were actually spinning at forty thousand revolutions per minute—turned obediently and without any appearance of the spectacular. Then Haney worked the controls. And Mike put the device through its paces.

Mike left the gyros spinning so that the main axis pointed at the sun, invisible beyond the Shed’s roof. And then all four of them watched. It took minutes for this last small test to show its results. But visibly and inexorably the pilot gyros followed the unseen sun, and they would have resisted with a force of very many tons any attempt to move them aside by so little as one-tenth of a second of arc, which would mean something like one three-hundred-thousandth of a right angle. And these pilot gyros would control the main gyros with just this precision, and after the Platform was out in space could hold the Platform itself with the steadiness needed for astronomical observation past achievement from the surface of the Earth.

The pilot gyros, in a word, were ready for installation.

Joe and Haney and the Chief and Mike were not beautiful to look at. They were begrimed from head to toe, and their eyes were bloodshot, and they were exhausted to the point where they did not even notice any longer that they were weary. And their mental processes were not at all normal, so that they were quarrelsome and arbitrary and arrogant to the men with the flat-bed trailer who came almost reverently to move their work. They went jealously with the thing they had rebuilt, and they were rude to engineers and construction workers and supervisors, and they shouted angrily at each other as it was hoisted up a shaft that had been left in the Platform for its entrance, and they were very far from tactful as they watched with hot, anxious eyes as it was bolted into place.

It would be welded later, but first it was tried out. And it moved the main gyros! They weighed many times what the pilot gyros did, but even when they were spinning the pilot gyros stirred them. Of course the main-gyro linkage to the fabric of the Shed had to be broken for this test, or the gyros would have twisted the giant upon its support and all the scaffolding around it would have been broken and the men on it killed.

But the gyros worked! They visibly and unquestionably worked! They controlled the gigantic wheels that would steer the Platform in its take-off, and later would swing it to receive the cargo rockets coming up from Earth. The pilot instrument worked! There was no vibration. In its steering apparatus the Platform was ready for space!

Then the Chief yawned, and his eyes glazed as he stood in the huge gyro room. And Haney’s knees wobbled, and he sat down and was instantly asleep. Then Joe vaguely saw somebody—it was Major Holt—holding Mike in his arms as if Mike were a baby. Mike would have resented it furiously if he had been awake. And then suddenly Joe didn’t know what was going on around him, either.

There was a definite hiatus in his consciousness. He came back to awareness very slowly. He was half-awake and half-asleep for a long time. He only knew contentedly that his job was finished. Then, slowly, he realized that he was in a bunk in one of the Platform sleeping cabins, and the inflated cover that was Sally’s contribution to the Platform held him very gently in place. Somehow it was infinitely soothing, and he had an extraordinary sensation of peacefulness and relaxation and fulfillment. The pilot gyros were finished and in position. His responsibility to them was ended. And he had slept the clock around three times. He’d slept for thirty-six hours. He was starving.

Sally had evidently constituted herself a watch over Joe as he slept, because she faced him immediately when he went groggily out of the cabin to look for a place to wash. He was still covered with the grime of past labor, and he had been allowed to sleep with only his shoes removed. He was not an attractive sight. But Sally regarded him with an approval that her tone belied.

“You can get a shower,” she told him firmly, “and then I’ll have some breakfast for you. Fresh clothes are waiting, too.”

Joe said peacefully: “The gyros are finished and they work!”

“Don’t I know?” demanded Sally. “Go get washed and come back for breakfast. The Chief and Haney and Mike are already awake. And because of the four of you, they’ve been able to advance the Platform’s take-off time—to just two days off! It leaked out, and now it’s official. And you made it possible!”

This was a slight exaggeration, but it was pardonable because of Sally’s partiality for Joe. He went groggily into the special shower arrangement in the Platform. In orbit, there would be no gravity, so a tub bath was unthinkable. The shower cabinet was a cubbyhole with handgrips on all four sides and straps into which one could slip his feet. When Joe turned handles, needle sprays sprang at him from all sides, and simultaneously a ventilator fan began to run. When in space that fan could draw out what would otherwise become an inchoate mixture of air and quite weightless water-drops. In space a man might drown in his own shower bath without the fan. The apparatus for collecting the water again was complex, but Joe didn’t think about that at the moment. He considered ruefully that however convenient this system might be out in the Platform’s orbit, it left something to be desired on Earth.

But there were clean clothes waiting when he came out. He dressed and felt brand new and utterly peaceful and rested, and it seemed to him very much like the way he had often felt on a new spring morning. It was very, very good!

Then he smelled coffee and became ravenous.

There were the others in the Platform’s kitchen, sitting in the chairs that had straps on them so the crew needn’t float about because of weightlessness. There was an argument in progress. The Chief grinned at Joe. Mike the midget looked absorbed. Haney was thinking something out, rather painfully. Sally was busy at the Platform’s very special stove. She had ham and eggs and pancakes ready for Joe to eat.

“Gentlemen,” she said, “you are about to eat the first meal ever cooked in a space ship—and like it!”

She served them and sat companionably down with them all. But her eyes were very warm when she looked at Joe.

“Leavin’ aside what we were arguin’ about,” said the Chief blissfully, “Sally here—mind if I call you Sally, ma’am?—she says the slide-rule guys have given our job the works and they say it’s a better job than they designed. Take a bow, Joe.”

Sally said firmly: “When the technical journals are through talking about the job you did, you’ll all four be famous for precision-machining technique and improvements on standard practices.”

“Which,” said the Chief sarcastically, “is gonna make us feel fine when we’re back to welding and stuff!”

“No more welding,” Sally told him. “Not on this job. The Platform’s closed in. They’ve started to take down the scaffolding.”

The Chief looked startled. Haney asked: “Laying off men yet?”

“Not you,” Sally assured him. “Definitely not you. You four have the very top super-special security rating there is! I think you’re the only four people in the world my father is sure can’t be reached, somehow, to make you harm the Platform.”

Mike said abruptly: “Yeah. The Major thought he had headaches before. Now he’s really got ’em!”

Mike hadn’t seemed to be listening. He’d acted as if he were feverishly absorbing the feel of being inside the Platform—not as a workman building it, but as a man whose proper habitat it would become. But Joe suddenly realized that his comment was exact. There’d been plenty of sabotage to prevent the Platform from reaching completion. But now it was ready to take off in two days. If it was to be stopped, it would have to be stopped within forty-eight hours by people with plenty of resources, who for their own evil ends needed it to be stopped. These last two days would contain the last-ditch, most desperate, most completely ruthless stepped-up attempts at destruction that could possibly be made. And Major Holt had to handle them.

But the four at table—five, with Sally—were peculiarly relaxed. The matter they’d handled had been conspicuous, perhaps, but it was still only one of thousands that had to be accomplished before the Platform could take off. But they had the infinitely restful feeling of a job well done.

“No more welding,” said Haney meditatively, “and our job on the gyros finished. What are we gonna do?”

The Chief said forcefully: “Me, I’m gonna sweep floors or something, but I’m sure gonna stick around and watch the take-off!”

Joe said nothing. He looked at Sally. She became very busy, making certain the others did not want more to eat. After a long time Joe said, with very careful casualness, “Come to think of it, I was getting loaded up with astrogation theory when I had to stop and pitch in on the gyros. How’s that sick crew member, Sally?”

“I—wouldn’t know,” answered Sally unconvincingly. “Have some more coffee?”

Joe made his face go completely expressionless. There was nothing else to do. Sally hadn’t said that his chances looked bad for making the crew of the Platform when it went out to space. But Sally had ways of knowing things. She would be sure to keep informed on a matter like that, because she was wearing Joe’s ring and it would have taken a great deal of discouragement to keep her from finding out good news to tell him. She didn’t have any good news. So it must be bad.

Joe drank his coffee, trying to make himself believe that he’d known all along he wasn’t going to make the crew. He’d started late to learn the things a crew member ought to know. He’d stopped at the most crucial part of his training to work on the gyros, which were more crucial still. He’d slept a day and a half. The platform would take off in forty-eight hours. He tried to reason carefully that it was common sense to use a man who was fully trained from the beginning for a place in the crew, rather than a latecomer like himself. But it wasn’t easy to take.

Mike the midget said suddenly: “I got a hunch.”

“Shoot it,” said the Chief, amiably.

“I got a hunch I know what kind of sabotage will be tried next—and when,” said Mike.

The others looked at him—all but Joe, who stared at the wall.

“There hasn’t been one set of guys trying to smash the Platform,” said Mike excitedly. “There’s been four or five. Joe found a gang sabotaging the pushpots that didn’t think like the gang that blackmailed Braun. And the gang that tried to kill us up at Red Canyon may be another. There could be others: fascists and commies and nationalists and crackpots of all kinds. And they all know they’ve got to work fast, even if they have to help each other. Get it?”

Haney growled.

“I’ll buy what you’ve said so far,” said the Chief. “Sure! Those so-and-sos will all pile in everything they got at the last minute. They’ll even pull together to smash the Platform—and then double-cross each other afterward. But what’ll they do, an’ when?”

“This time they’ll try outright violence,” said Mike coldly, “instead of sneaking. They’ll try something really rough. For sneaking, one time’s as good as another, but for really rough stuff, there’s just one time when the Platform hasn’t got plenty of guys around ready to fight for it.”

The Chief whistled softly.

“You mean change-shift time! Which one?”

“The first one possible,” said Mike briefly. “After every shift, things will get tighter. So my guess is the next shift, if they can. And if one gang starts something, the others will have to jump right in. You see?”

That made sense. One attempt at actual violence, defeated, would create a rigidity of defense that would make others impossible. If a successful attempt at violent sabotage was to be made, the efforts of all groups would have to be timed to the first, or abandoned.

“I could—uh—set up a sort of smoke screen,” said Mike. “We’ll fake we’re going to smash something—and let those saboteurs find it out. They’ll see it as a chance to do their stuff with us to run interference for them.—Sally, does your father sure-enough trust us?”

Sally nodded.

“He doesn’t talk very cordially, but he trusts you.”

“Okay,” said Mike. “You tell him, private, that I’m setting up something tricky. He can laugh off anything his security guys report that I’m mixed up in. Joe’ll see that he gets the whole picture beforehand. But he ain’t to tell anybody—not anybody—that something is getting framed up. Right?”

“I’ll ask him,” said Sally. “He is pretty desperate. He’s sure some last-minute frantic assault on the Platform will be made. But——”

“We’ll tip him in plenty of time,” said Mike with authority. “In time for him to play along, but not for a leak to spoil things. Okay?”

“I’ll make the bargain,” Sally assured him, “if it can be made.”

Mike nodded. He drained his coffee cup and slipped down from his chair.

“Come on, Chief! C’mon, Haney!”

He led them out of the room.

Joe fiddled with his spoon a moment, and then said: “The crewman I was to have subbed for if he didn’t get well—he did, didn’t he?”

Sally answered reluctantly: “Y-yes.”

Joe said measuredly: “Well, then—that’s that! I guess it will be all right for me to stick around and watch the take-off?”

Sally’s eyes were misty.

“Of course it will, Joe! I’m so sorry!”

Joe grinned, but even to himself his face seemed like a mask.

“Into each life some rain must fall. Let’s go out and see what’s been accomplished since I went to sleep. All right?”

They went out of the Platform together. And as soon as they reached the floor of the Shed it was plain that the stage had been set for stirring events.

The top five or six levels of scaffolding had already been removed, and more of the girders and pipes were coming down in bundles on lines from giraffelike cranes. There were some new-type trucks in view, too, giants of the kind that carry ready-mixed concrete through city streets. They were pouring a doughy white paste into huge buckets that carried it aloft, where it vanished into the mouths of tubes that seemed to replace the scaffolding along the Platform’s sides.

“Lining the rockets,” said Sally in a subdued voice.

Joe watched. He knew about this, too. It had been controversial for a time. After the pushpots and their jatos had served as the first two stages of a multiple-rocket aggregation, the Platform carried rocket fuel as the third stage. But the Platform was a highly special ballistic problem. It would take off almost horizontally—a great advantage in fueling matters. This was practical simply because the Platform could be lifted far beyond effective air resistance, and already have considerable speed before its own rockets flared.

Moreover, it was not a space ship in the sense of needing rockets for landing purposes. It wouldn’t land. Not ever. And again there was the fact that men would be riding in it. That ruled out the use of eight- and ten- and fifteen-gravity acceleration. It had to make use of a long period of relatively slow acceleration rather than a brief terrific surge of power. So its very special rockets had been designed as the answer.

They were solid-fuel rockets, though solid fuels had been long abandoned for long-range missiles. But they were entirely unlike other solid-fuel drives. The pasty white compound being hauled aloft was a self-setting refractory compound with which the rocket tubes would be lined, with the solid fuel filling the center. The tubes themselves were thin steel—absurdly thin—but wound with wire under tension to provide strength against bursting, like old-fashioned rifle cannon.

When the fuel was fired, it would be at the muzzle end of the rocket tube, and the fuel would burn forward at so many inches per second. The refractory lining would resist the rocket blast for a certain time and then crumble away. Crumbling, the refractory particles would be hurled astern and so serve as reaction mass. When the steel outer tubes were exposed, they would melt and be additional reaction mass.

In effect, as the rocket fuel was exhausted, the tubes that contained it dissolved into their own blast and added to the accelerating thrust, even as they diminished the amount of mass to be accelerated. Then the quantity of fuel burned could diminish—the tubes could grow smaller—so the rate of speed gain would remain constant. Under the highly special conditions of this particular occasion, there was a notable gain in efficiency over a liquid-fuel rocket design. For one item, the Platform would certainly have no use for fuel pumps and fuel tanks once it was in its orbit. In this way, it wouldn’t have them. Their equivalent in mass would have been used to gain velocity. And when the Platform finally rode in space, it would have expended every ounce of the driving apparatus used to get it there.

Now the rocket tubes were being lined and loaded. The time to take-off was growing short indeed.

Joe watched a while and turned away. He felt very good because he’d finished his job and lived up to the responsibility he’d had. But he felt very bad because he’d had an outside chance to be one of the first men ever to make a real space journey—and now it was gone. He couldn’t resent the decision against him. If it had been put up to him, he’d probably have made the same hard decision himself. But it hurt to have had even a crazy hope taken away.

Sally said, trying hard to interest him, “These rockets hold an awful lot of fuel, Joe! And it’s better than scientists thought a chemical fuel could ever be!”

“Yes,” said Joe.

“Fluorine-beryllium,” said Sally urgently. “It fits in with the pushpots’ having pressurized cockpits. Rockets like that couldn’t be used on the ground! The fumes would be poisonous!”

But Joe only nodded in agreement. He was apathetic. He was uninterested. He was still thinking of that lost trip in space. He realized that Sally was watching his face.

“Joe,” she said unhappily, “I wish you wouldn’t look like that!”

“I’m all right,” he told her.

“You act as if you didn’t care about anything,” she protested, “and you do!”

“I’m all right,” he repeated.

“I’d like to go outside somewhere,” she said abruptly, “but after what happened up at the lake, I mustn’t. Would you like to go up to the top of the Shed?”

“If you want to,” he agreed without enthusiasm.

He followed when she went to a doorway—with a security guard beside it—in the sidewall. She flashed her pass and the guard let them through. They began to walk up an inclined, endless, curving ramp. It was between the inner and outer skins of the Shed. There had to be two skins because the Shed was too big to be ventilated properly, and the hot desert sunshine on one side would have made “weather” inside. There’d have been a convection-current motion of the air in the enclosed space, and minor whirlwinds, and there could even be miniature thunderclouds and lightning. Joe remembered reading that such things had happened in a shed built for Zeppelins before he was born.

They came upon an open gallery, and there was a security man looking down at the floor and the Platform. He had a very good view of all that went on.

They went around another long circuit of the slanting gallery, dimly lighted with small electric bulbs. They came to a second gallery, and saw the Platform again. There was another guard here.

They were halfway up the globular wall now, and were visibly suspended over emptiness. The view of the Platform was impressive. There were an astonishing number of rocket tubes being fastened to the outside of that huge object. Three giant cranes, working together, hoisted a tube to the last remaining level of scaffolding, and men swarmed on it and fastened it to the swelling hull. As soon as it was fast, other men hurried into it with the white pasty stuff to line it from end to end. The tubes would nearly hide the structure they were designed to propel. But they’d all be burned away when it reached its destination.

“Wonderful, isn’t it?” asked Sally hopefully.

Joe looked, and said without warmth, “It’s the most wonderful thing that anybody ever even tried to do.”

Which was true enough, but the zest of it had unreasonably departed for Joe for the time being. His disappointment was new.

Halfway around again, Sally opened a door, and Joe was almost surprised out of his lethargy. Here was a watching post on the outside of the monstrous half-globe. There were two guards here, with fifty-caliber machine guns under canvas hoods. Their duties were tedious but necessary. They watched the desert. From this height it stretched out for miles, and Bootstrap could be seen as a series of white specks far away with hills behind it.

Ultimately Sally and Joe came to the very top of the Shed into the open air. From here the steep plating curved down and away in every direction. The sunshine was savagely bright and shining, but there was a breeze. And here there was a considerable expanse fenced in—almost an acre, it seemed. There were metal-walled small buildings with innumerable antennae of every possible shape for the reception of every conceivable wave length. There were three radar bowl reflectors turning restlessly to scan the horizon, and a fourth which went back and forth, revolving, to scan the sky itself. Sally told Joe that in the very middle—where there was a shed with a domelike roof which wasn’t metal—there was a wave-guide radar that could spot a plane within three feet vertically, and horizontally at a distance of thirty miles, with greater distances in proportion.

There were guns down in pits so their muzzles wouldn’t interfere with the radar. There were enough non-recoil anti-aircraft guns to defend the Shed against anything one could imagine.

“And there are jet planes overhead too,” said Sally. “Dad asked to have them reinforced, and two new wings of jet fighters landed yesterday at a field somewhere over yonder. There are plenty of guards!”

The Platform was guarded as no object in all history had ever been guarded. It was ironic that it had to be protected so, because it was actually the only hope of escape from atomic war. But that was why some people hated the Platform, and their hatred had made it seem obviously an item of national defense. Ironically that was the reason the money had been provided for its construction. But the greatest irony of all was that its most probable immediate usefulness would be the help it would give in making nuclear experiments that weren’t safe enough to make on Earth.

That was pure irony. Because if those experiments were successful, they should mean that everybody in the world would in time become rich beyond envy.

But Joe couldn’t react to the fact. He was drained and empty of emotion because his job was done and he’d lost a very flimsy hope to be one of the Platform’s first crew.

He didn’t really feel better until late that night, when suddenly he realized that life was real and life was earnest, because a panting man was trying to strangle Joe with his bare hands. Joe was hampered in his self-defense because a large number of battling figures trampled over him and his antagonist together. They were underneath the Platform, and Joe expected to be blown to bits any second.

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