It was a merely misty day. The transport plane stood by the door of a hangar on this military field, and mechanics stood well back from it and looked it over. A man crawled over the tail assembly and found one small hole in the fabric of the stabilizer. A shell fragment had gone through when the war rockets exploded nearby. The pilot verified that the fragment had hit no strengthening member inside. He nodded. The mechanic made very neat fabric patches over the two holes, upper and lower. He began to go over the fuselage. The pilot turned away.

“I’ll go talk to Bootstrap,” he told the co-pilot. “You keep an eye on things.”

“I’ll keep two eyes on them,” said the co-pilot.

The pilot went toward the control tower of the field. Joe looked around. The transport ship seemed very large, standing on the concrete apron with its tricycle landing gear let down. It curiously resembled a misshapen insect, standing elaborately high on inadequate supporting legs. Its fuselage, in particular, did not look right for an aircraft. The top of the cargo section went smoothly back to the stabilizing fins, but the bottom did not taper. It ended astern in a clumsy-looking bulge that was closed by a pair of huge clamshell doors, opening straight astern. It was built that way, of course, so that large objects could be loaded direct into the cargo hold, but it was neither streamlined nor graceful.

“Did anything get into the cargo hold?” asked Joe in sudden anxiety. “Did the cases I’m with get hit?”

After all, four rockets had exploded deplorably near the ship. If one fragment had struck, others might have.

“Nothing big, anyhow,” the co-pilot told him. “We’ll know presently.”

But examination showed no other sign of the ship’s recent nearness to destruction. It had been overstressed, certainly, but ships are built to take beatings. A spot check on areas where excessive flexing of the wings would have shown up a big ship’s wings are not perfectly rigid: they’d come to pieces in the air if they were presented no evidence of damage. The ship was ready to take off again.

The co-pilot watched grimly until the one mechanic went back to the side lines. The mechanic was not cordial. He and all the others regarded the ship and Joe and the co-pilot with disfavor. They worked on jets, and to suggest that men who worked on fighter jets were not worthy of complete confidence did not set well with them. The co-pilot noticed it.

“They think I’m a suspicious heel,” he said sourly to Joe, “but I have to be. The best spies and saboteurs in the world have been hired to mess up the Platform. When better saboteurs are made, they’ll be sent over here to get busy!”

The pilot came back from the control tower.

“Special flight orders,” he told his companion. “We top off with fuel and get going.”

Mechanics got out the fuel hose, dragging it from the pit. One man climbed up on the wing. Other men handed up the hose. Joe was moved to comment, but the co-pilot was reading the new flight instructions. It was one of those moments of inconsistency to which anybody and everybody is liable. The two men of the ship’s crew had it in mind to be infinitely suspicious of anybody examining their ship. But fueling it was so completely standard an operation that they merely stood by absently while it went on. They had the orders to read and memorize, anyhow.

One wing tank was full. A big, grinning man with sandy hair dragged the hose under the nose of the plane to take it to the other wing tank. Close by the nose wheel he slipped and steadied himself by the shaft which reaches down to the wheel’s hub. His position for a moment was absurdly ungraceful. When he straightened up, his arm slid into the wheel well. But he dragged the hose the rest of the way and passed it on up. Then that tank was full and capped. The refueling crew got down to the ground and fed the hose back to the pit which devoured it. That was all. But somehow Joe remembered the sandy-haired man and his arm going up inside the wheel well for a fraction of a second.

The pilot read one part of the flight orders again and tore them carefully across. One part he touched his pocket lighter to. It burned. He nodded yet again to the co-pilot, and they swung up and in the pilots’ doorway. Joe followed.

They settled in their places in the cabin. The pilot threw a switch and pressed a knob. One motor turned over stiffly, and caught. The second. Third. Fourth. The pilot listened, was satisfied, and pulled back on the multiple throttle. The plane trundled away. Minutes later it faced the long runway, a tinny voice from the control tower spoke out of a loud-speaker under the instruments, and the plane roared down the field. In seconds it lifted and swept around in a great half-circle.

“Okay,” said the pilot. “Wheels up.”

The co-pilot obeyed. The telltale lights that showed the wheels retracted glowed briefly. The men relaxed.

“You know,” said the co-pilot, “there was the devil of a time during the War with sabotage. Down in Brazil there was a field planes used to take off from to fly to Africa. But they’d take off, head out to sea, get a few miles offshore, and then blow up. We must’ve lost a dozen planes that way! Then it broke. There was a guy a sergeant in the maintenance crew who was sticking a hand grenade up in the nose wheel wells. German, he was, and very tidy about it, and nobody suspected him. Everything looked okay and tested okay. But when the ship was well away and the crew pulled up the wheels, that tightened a string and it pulled the pin out of the grenade. It went off.... The master mechanic finally caught him and nearly killed him before the MPs could stop him. We’ve got to be plenty careful, whether the ground crews like it or not.”

Joe said drily: “You were, except when they were topping off. You took that for granted.” He told about the sandy-haired man. “He hadn’t time to stick anything in the wheel well, though,” he added.

The co-pilot blinked. Then he looked annoyed. “Confound it! I didn’t watch! Did you?”

The pilot shook his head, his lips compressed.

The co-pilot said bitterly: “And I thought I was security-conscious! Thanks for telling me, fella. No harm done this time, but that was a slip!”

He scowled at the dials before him. The plane flew on.

This was the last leg of the trip, and now it should be no more than an hour and a half before they reached their destination. Joe felt a lift of elation. The Space Platform was a realization or the beginning of it of a dream that had been Joe’s since he was a very small boy. It was also the dream of most other small boys at the time. The Space Platform would make space travel possible. Of course it wouldn’t make journeys to the moon or planets itself, but it would sail splendidly about the Earth in an orbit some four thousand miles up, and it would gird the world in four hours fourteen minutes and twenty-two seconds. It would carry atom-headed guided missiles, and every city in the world would be defenseless against it. Nobody could even hope for world domination so long as it floated on its celestial round. Which, naturally, was why there were such desperate efforts to destroy it before its completion.

But Joe, thinking about the Platform, did not think about it as a weapon. It was the first rung on the stepladder to the stars. From it the moon would be reached, certainly. Mars next, most likely. Then Venus. In time the moons of Saturn, and the twilight zone of Mercury, and some day the moons of Jupiter. Possibly a landing could be dared on that giant planet itself, despite its gravity.

The co-pilot spoke suddenly. “How do you rate this trip by cargo plane?” he asked curiously. “Mostly even generals have to go on the ground. You rate plenty. How?”

Joe pulled his thoughts back from satisfied imagining. It hadn’t occurred to him that it was remarkable that he should be allowed to accompany the gyros from the plant to their destination. His family firm had built them, so it had seemed natural to him. He wasn’t used to the idea that everybody looked suspicious to a security officer concerned with the safety of the Platform.

“Connections? I haven’t any,” said Joe. Then he said, “I do know somebody on the job. There’s a Major Holt out there. He might have cleared me. Known my family for years.”

“Yeah,” said the co-pilot drily. “He might. As a matter of fact, he’s the senior security officer for the whole job. He’s in charge of everything, from the security guards to the radar screens and the jet-plane umbrella and the checking of the men who work in the Shed. If he says you’re all right, you probably are.”

Joe hadn’t meant to seem impressive. He explained: “I don’t know him too well. He knows my father, and his daughter Sally’s been kicking around underfoot most of my life. I taught her how to shoot, and she’s a better shot than I am. She was a nice kid when she was little. I got to like her when she fell out of a tree and broke her arm and didn’t even whimper. That shows how long ago it was!” He grinned. “She was trying to act grown-up last time I saw her.”

The co-pilot nodded. There was a brisk chirping sound somewhere. The pilot reached ahead to the course-correction knob. The plane changed course. Sunshine shifted as it poured into the cabin. The ship was running on automatic pilot well above the cloud level, and at an even-numbered number of thousands of feet altitude, as was suitable for planes traveling south or west. Now it droned on its new course, forty-five degrees from the original. Joe found himself guessing that one of the security provisions for planes approaching the Platform might be that they should not come too near on a direct line to it, lest they give information to curious persons on the ground.

Time went on. Joe slipped gradually back to his meditations about the Platform. There was always, in his mind, the picture of a man-made thing shining in blinding sunlight between Earth and moon. But he began to remember things he hadn’t paid too much attention to before.

Opposition to the bare idea of a Space Platform, for instance, from the moment it was first proposed. Every dictator protested bitterly. Even politicians out of office found it a subject for rabble-rousing harangues. The nationalistic political parties, the peddlers of hate, the entrepreneurs of discord every crank in the world had something to say against the Platform from the first. When they did not roundly denounce it as impious, they raved that it was a scheme by which the United States would put itself in position to rule all the Earth. As a matter of fact, the United States had first proposed it as a United Nations enterprise, so that denunciations that politicians found good politics actually made very poor sense. But it did not get past the General Assembly. The proposal was so rabidly attacked on every side that it was not even passed up to the Council where it would certainly have been vetoed anyhow.

But it was exactly that furious denunciation which put the Platform through the United States Congress, which had to find the money for its construction.

In Joe’s eyes and in the eyes of most of those who hoped for it from the beginning, the Platform’s great appeal was that it was the necessary first step toward interplanetary travel, with star ships yet to come. But most scientists wanted it, desperately, for their own ends. There were low-temperature experiments, electronic experiments, weather observations, star-temperature measurements, astronomical observations.... Any man in any field of science could name reasons for it to be built. Even the atom scientists had one, and nearly the best. Their argument was that there were new developments of nuclear theory that needed to be tried out, but should not be tried out on Earth. There were some reactions that ought to yield unlimited power for all the world from really abundant materials. But there was one chance in fifty that they wouldn’t be safe, just because the materials were so abundant. No sane man would risk a two-per-cent chance of destroying Earth and all its people, yet those reactions should be tried. In a space ship some millions of miles out in emptiness they could be. Either they’d be safe or they would not. But the only way to get a space ship a safe enough distance from Earth was to make a Space Platform as a starting point. Then a ship could shoot away from Earth with effectively zero gravity and full fuel tanks. The Platform should be built so civilization could surge ahead to new heights!

But despite these excellent reasons, it was the Platform’s enemies who really got it built. The American Congress would never have appropriated funds for a Platform for pure scientific research, no matter what peacetime benefits it promised. It was the vehemence of those who hated it that sold it to Congress as a measure for national defense. And in a sense it was.

These were ironic aspects Joe hadn’t thought about before, just as he hadn’t thought about the need to defend the Platform while it was being built. Defending it was Sally’s father’s job, and he wouldn’t have a popular time. Joe wondered idly how Sally liked living out where the most important job on Earth was being done. She was a nice kid. He remembered appreciatively that she’d grown up to be a very good-looking girl. He tended to remember her mostly as the tomboy who could beat him swimming, but the last time he’d seen her, come to think of it, he’d been startled to observe how pretty she’d grown. He didn’t know anybody who ought to be better-looking.... She was a really swell girl....

He came to himself again. There was a change in the look of the sky ahead. There was no actual horizon, of course. There was a white haze that blended imperceptibly into the cloud layer so that it was impossible to tell where the sky ended and the clouds or earth began. But presently there were holes in the clouds. The ship droned on, and suddenly it floated over the edge of such a hole, and looking down was very much like looking over the edge of a cliff at solid earth illimitably far below.

The holes increased in number. Then there were no holes at all, but only clouds breaking up the clear view of the ground beneath. And presently again even the clouds were left behind and the air was clear but still there was no horizon and there was brownish earth with small green patches and beyond was sere brown range. At seventeen thousand feet there were simply no details.

Soon the clouds were merely a white-tipped elevation of the white haze to the sides and behind. And then there came a new sound above the droning roar of the motors. Joe heard it and then he saw.

Something had flashed down from nowhere. It flashed on ahead and banked steeply. It was a fighter jet, and for an instant Joe saw the distant range seem to ripple and dance in its exhaust blast. It circled watchfully.

The transport pilot manipulated something. There was a change in the sound of the motors. Joe followed the co-pilot’s eyes. The jet fighter was coming up astern, dive brakes extended to reduce its speed. It overhauled the transport very slowly. And then the transport’s pilot touched one of the separate prop-controls gently, and again, and again. Joe, looking at the jet, saw it through the whirling blades. There was an extraordinary stroboscopic effect. One of the two starboard propellers, seen through the other, abruptly took on a look which was not that of mistiness at all, but of writhing, gyrating solidity. The peculiar appearance vanished, and came again, and vanished and appeared yet again before it disappeared completely.

The jet shot on ahead. Its dive brakes retracted. It made a graceful, wallowing, shallow dive, and then climbed almost vertically. It went out of sight.

“Visual check,” said the co-pilot drily, to Joe. “We had a signal to give. Individual to this plane. We didn’t tell it to you. You couldn’t duplicate it.”

Joe worked it out painfully. The visual effect of one propeller seen through another that was identification. It was not a type of signaling an unauthorized or uninformed passenger would expect.

“Also,” said the co-pilot, “we have a television camera in the instrument board yonder. We’ve turned it on now. The interior of the cabin is being watched from the ground. No more tricks like the phony colonel and the atom bomb that didn’t ‘explode.’”

Joe sat quite still. He noticed that the plane was slanting gradually downward. His eyes went to the dial that showed descent at somewhere between two and three hundred feet a minute. That was for his benefit. The cabin was pressurized, though it did not attempt to simulate sea-level pressure. It was a good deal better than the outside air, however, and yet too quick a descent meant discomfort. Two to three hundred feet per minute is about right.

The ground took on features. Small gulleys. Patches of coloration too small to be seen from farther up. The feeling of speed increased. After long minutes the plane was only a few thousand feet up. The pilot took over manual control from the automatic pilot. He seemed to wait. There was a plaintive, mechanical beep-beep and he changed course.

“You’ll see the Shed in a minute or two,” said the co-pilot. He added vexedly, as if the thing had been bothering him, “I wish I hadn’t missed that sandy-haired guy putting his hand in the wheel well! Nothing happened, but I shouldn’t have missed it!”

Joe watched. Very, very far away there were mountains, but he suddenly realized the remarkable flatness of the ground over which they were flying. From the edge of the world, behind, to the very edge of these far-distant hills, the ground was flat. There were gullies and depressions here and there, but no hills. It was flat, flat, flat....

The plane flew on. There was a tiny glimmer of sunlight. Joe strained his eyes. The sunlight glinted from the tiniest possible round pip on the brown earth. It grew as the plane flew on. It was half a cherry stone. It was half an orange, with gores. It was the top section of a sphere that was simply too huge to have been made by men.

There was a thin thread of white that ran across the dun-colored range and reached that half-ball and then ended. It was a highway. Joe realized that the half-globe was the Shed, the monstrous building made for the construction of the Space Platform. It was gigantic. It was colossal. It was the most stupendous thing that men had ever created.

Joe saw a tiny projection near the base of it. It was an office building for clerks and timekeepers and other white-collar workers. He strained his eyes again and saw a motor truck on the highway. It looked extraordinarily flat. Then he saw that it wasn’t a single truck but a convoy of them. A long way back, the white highway was marked by a tiny dot. That was a motor bus.

There was no sign of activity anywhere, because the scale was so great. Movement there was, but the things that moved were too small to be seen by comparison with the Shed. The huge, round, shining half-sphere of metal stood tranquilly in the midst of emptiness.

It was bigger than the pyramids.

The plane went on, descending. Joe craned his neck, and then he was ashamed to gawk. He looked ahead, and far away there were white speckles that would be buildings: Bootstrap, the town especially built for the men who built the Space Platform. In it they slept and ate and engaged in the uproarious festivity that men on a construction job crave on their time off.

The plane dipped noticeably.

“Airfield off to the right,” said the co-pilot. “That’s for the town and the job. The jets there’s an air umbrella overhead all the time have a field somewhere else. The pushpots have a field of their own, too, where they’re training pilots.”

Joe didn’t know what a pushpot was, but he didn’t ask. He was thinking about the Shed, which was the greatest building ever put up, and had been built merely to shelter the greatest hope for the world’s peace while it was put together. He’d be in the Shed presently. He’d work there, setting up the contents of the crates back in the cargo space, and finally installing them in the Platform itself.

The pilot said: “Pitot and wing heaters?”

“Off,” said the co-pilot.

“Spark and advance 

Joe didn’t listen. He looked down at the sprawling small town with white-painted barracks and a business section and an obvious, carefully designed recreation area that nobody would ever use. The plane was making a great half-circle. The motor noise dimmed as Joe became absorbed in his anticipation of seeing the Space Platform and having a hand in its building.

The co-pilot said sharply: “Hold everything!”

Joe jerked his head around. The co-pilot had his hand on the wheel release. His face was tense.

“It don’t feel right,” he said very, very quietly. “Maybe I’m crazy, but there was that sandy-haired guy who put his hand up in the wheel well back at that last field. And this don’t feel right!”

The plane swept on. The airfield passed below it. The co-pilot very cautiously let go of the wheel release, which when pulled should let the wheels fall down from their wells to lock themselves in landing position. He moved from his seat. His lips were pinched and tight. He scrabbled at a metal plate in the flooring. He lifted it and looked down. A moment later he had a flashlight. Joe saw the edge of a mirror. There were two mirrors down there, in fact. One could look through both of them into the wheel well.

The co-pilot made quite sure. He stood up, leaving the plate off the opening in the floor.

“There’s something down in the wheel well,” he said in a brittle tone. “It looks to me like a grenade. There’s a string tied to it. At a guess, that sandy-haired guy set it up like that saboteur sergeant down in Brazil. Only it rolled a little. And this one goes off when the wheels go down. I think, too, if we belly-land  Better go around again, huh?”

The pilot nodded. “First,” he said evenly, “we get word down to the ground about the sandy-haired guy, so they’ll get him regardless.”

He picked up the microphone hanging above and behind him and began to speak coldly into it. The transport plane started to swing in wide, sweeping circles over the desert beyond the airport while the pilot explained that there was a grenade in the nose wheel well, set to explode if the wheel were let down or, undoubtedly, if the ship came in to a belly landing.

Joe found himself astonishingly unafraid. But he was filled with a pounding rage. He hated the people who wanted to smash the pilot gyros because they were essential to the Space Platform. He hated them more completely than he had known he could hate anybody. He was so filled with fury that it did not occur to him that in any crash or explosive landing that would ruin the gyros, he would automatically be killed.