There was a babbling of angry, strained, tense voices in Joe's headphones. Then the Chief roared for silence. It fell, save for Sanford's quiet, hysterical chuckling. Joe found himself rather absurdly thinking that Sanford was not actually insane, except as any man may be who believes only in his own cleverness. Sooner or later it is bound to fail him. On Earth, Sanford's pride in his own intellect had been useful. He had been brilliant because he accepted every problem and every difficulty as a challenge. But with the Platform's situation seemingly hopeless, he'd been starkly unable to face the fact that he wasn't clever or brilliant or intelligent enough. If Joe's solution to the proximity fuse bombs had been offered before his emotional collapse, he could have accepted it grandly, and in so doing have made it his own. But it was too late for that now. He'd given up and worked up a frantic scorn for the universe he could not cope with. For Joe's trick to work would have made him inferior even to Joe in his own view. And he couldn't have that! Even to die, with the prospect that others would survive him, was an intolerable prospect. He had to be smarter than anybody else.

So he chuckled. The Chief roared wrathfully into his transmitter: "Quiet! This crazy fool's tried to commit suicide for all of us! How about it? Why can't we get back in? How many locks——"

Joe found himself thinking hard. He could be angry later. Now there wasn't time. Thirty or forty minutes of breathing. No tools. A steel hull. The airlocks were naturally arranged for the greatest possible safety under normal conditions. In every airlock it had naturally been arranged so that the door to space and the door to the interior could not be open at the same time. That was to save lives. To save air, it would naturally be arranged that the door to space couldn't be opened until the lock was pumped empty.

That in itself could be an answer. Joe said sharply, "Hold it, Chief! Somebody watch Sanford! All we've got to do is find which lock he came out of. He couldn't get out until he pumped it empty—and that unlocks the outer door!"

But Sanford laughed once more. He sounded like someone in the highest of high good humor.

"Heroic again, eh? But I took a compressed air bottle in the lock with me. When the outer door was open, I opened the stopcock and shut the door. The air bottle filled the lock behind me. Naturally I'd fasten the door after I came out! One must be intelligent!"

Joe heard Brent muttering, "Yes, he'd do that!"

"Somebody check it!" snapped Joe. "Make sure! It might amuse him to watch us die while he knew we could get back in if we were as smart as he is."

There were clankings on the hull. Men moved, unfastening the lines which held them to the hull to get freedom of movement, but not breaking the links which bound them to each other. Joe saw Haney go grimly back to the task of throwing away the stuff that they had brought out for the purpose. Then Mike's voice, brittle and cagey: "Haney! Quit it!"

Sanford's voice again, horribly amused. "By all means! Don't throw away our garbage! We may need it!"

A voice snapped, "This lock's fastened." Another voice: "And this...." Other voices, with increasing desperation, verified that every airlock was implacably sealed fast by the presence of air pressure inside the lock itself.

Time was passing. Joe had never noticed, before, the minute noises of the air pressure apparatus strapped to his back. His exhaled breath went to a tiny pump that forced it through a hygroscopic filter which at once extracted excess moisture and removed carbon dioxide. The same pump carefully measured a volume of oxygen equal to the removed CO₂ and added it to the air it released. The pump made very small sounds indeed, and the valves were almost noiseless, but Joe could hear their clickings.

Something burned him. He had been standing perfectly still while trying to concentrate on a way out. Sunshine had shone uninterruptedly on one side of his space suit for as long as five minutes. Despite the insulation inside, that was too long. He turned quickly to expose another part of himself to the sunlight. He knew abstractedly that the metal underfoot would sear bare flesh that touched it. A few yards away, in the shadow, the metal of the hull would be cold enough to freeze hydrogen. But here it was fiercely hot. It would melt solder. It might—

Mike was fumbling tin cans out of the net bag from which Haney had been throwing them away. He was a singular small figure, standing on shining steel, looking at one tin can after another and impatiently putting them aside.

He found one that seemed to suit him. It was a large can. He knelt with it, pressing a part of it to the hot metal of the satellite's hull. A moment later he was ripping it apart. The solder had softened. He unrolled a sort of cylinder, then bent again, using the curved inner surface to concentrate the intolerable sunshine.

Joe caught his breath at the implication. Concentrated sunshine can be incredibly hot. Starting with unshielded, empty-space sunshine, practically any imaginable temperature is possible with a large enough mirror. Mike didn't have a concave mirror. He had only a cylindrical one. He couldn't reflect light to a point, but only to a line. Mike couldn't hope to do more than double or triple the temperature of a given spot. But considering what he wore on his back—!

Joe made his way clumsily to the spot where Mike now gesticulated to Haney, trying to convey his meaning by gestures since Sanford would overhear any spoken word.

"I get it, Mike," said Joe. "I'll help." He added: "Chief! You watch Sanford. The rest of you try to flatten out some tin cans or find some with flat round ends!"

He reached the spot where Mike bent over the plating. His hand moved to cast a shadow where the light had played.

"I need more reflectors," Mike said brusquely, "but we can do it!"

Joe beckoned. There were more, hurried clankings. Space-suited figures gathered about.

The Platform rolled on through space. Where it was bright it was very, very bright, and where it was dark it was blackness. Off in emptiness the many-colored mass of Earth shone hugely, rolling past. Innumerable incurious stars looked on. The sun flamed malevolently. The moon floated abstractedly far away.

Mike was bent above a small round airlock door. He had a distorted half-cylinder of sheet tin between his space-gloved hands. It reflected a line of intensified sunlight to the edge of the airlock seal. Haney ripped fiercely at other tin cans. Joe held another strip of polished metal. It focused crudely—very crudely—on top of Mike's line of reflected sunshine. Someone else held the end of a tin can to reflect more sunshine. Someone else had a larger disk of tin.

They stood carefully still. It looked completely foolish. There were six men in frozen attitudes, trying to reflect sunshine down to a single blindingly-bright spot on an airlock door. They seemed breathlessly tense. They ignored the glories of the firmament. They were utterly absorbed in trying to make a spot of unbearable brightness glow more brightly still.

Mike moved his hand to cast a shadow. The steel was a little more than red-hot for the space of an inch. It would not melt, of course. It could not. And they had no tools to bend or pierce the presumably softened metal. But Mike said fiercely:

"Keep it hot!"

He squirmed. His space suit was fabric, like the rest, but it had been cut down to permit him to use it. It was bulkier on him than the suits of the others. He shifted his shoulder pack. The brass valve-nipple by which the oxygen tank was filled....

He jammed a ragged fragment of tin in place. He pressed down fiercely. A blazing jet of fierce, scintillating, streaking sparks leaped up from the spot where the metal glowed brightly. A hollow in the metal plate appeared. The metal disintegrated in gushing flecks of light....

White-hot iron in pure oxygen happens to be inflammable. Iron is not incombustible at all. Powdered steel, ground fine enough, will burn if simply exposed to air. Really fine steel wool will make an excellent blaze if a match is touched to it. White-hot iron, with a jet of oxygen played upon it, explodes to steaming sparks. Technically, Mike had used the perfectly well-known trick of an oxygen lance to pierce the airlock door, let the air out of the lock, and so allow the outer door to be opened.

There was a rush of vapor. The door was drilled through. Haney picked Mike up bodily, Joe heaved the door open, and Haney climbed into it, practically carrying Mike by the scruff of the neck. Joe panted, "Plug the hole from the inside. Sit on it if you have to!" and slammed the door shut.

They waited. Sanford's voice came in the ear-phones. It was higher in pitch than it had been.

"You fools!" he raged. "It's useless! It's stupid to do useless things! It's stupid to do anything at all—"

There were sudden scuffling clankings. Joe swung about. The Chief and Sanford were struggling. Sanford flailed his arms about, trying to break the Chief's faceplate while he screamed furious things about futility.

The Chief got exactly the hold he wanted. He lifted Sanford from the metal deck. He could have thrown him away to emptiness, then, but he did not.

He set Sanford in mid-space as if upon a shelf. The raging man hung in the void an exact man-height above the Platform's surface. The Chief drew back and left him there, Sanford could writhe there for a century before the Platform's infinitesimal gravity brought him down.

"Huh!" said the Chief wrathfully. "How's Haney and Mike making out?"

Almost on the instant, twenty yards away, a tiny airlock door thrust out from the surface of glittering metal, and helmet and antenna appeared.

"You guys can come in now," said Haney's voice in Joe's headphones. "It's all okay. Mike's pumping out the other locks too, so you can come in at any of 'em."

The space-suited figures clumped loudly to airlock doors. There were a dozen or more small airlocks in various parts of the hull, besides the great door to admit supply ships. The Chief growled and moved toward Sanford now raging like the madman his helplessness made him.

"No," said Joe shortly. "He'd fight again. Go inside. That's an order, Chief."

The Chief grunted and obeyed. Joe went to the nearest airlock and entered the great steel hull.

Sanford floated in emptiness, two yards from the Space Platform he would have turned into a derelict. He did not move farther away. He did not fall toward it. There was nobody to listen to him. He cried out in blood-curdling fury because other men were smarter than he was. Other men had solved problems he could not solve. Other men were his superiors. He screamed his rage.

Presently the Platform revolved slowly beneath him. It was turned, of course, by the monster gyros which in turn were controlled by the pilot gyros Joe and Haney and the Chief and Mike had repaired when saboteurs smashed them.

The Platform rotated sedately. A great gap appeared in it. The door of the supply ship lock moved until Sanford, floating helplessly, was opposite its mouth.

A rod with a rounded object at its end appeared past the docked supply ship. It reached out and touched Sanford's helmet. It was the magnetic grapple which drew space ships into their dock.

It drew Sanford, squirming and streaming, into the great lock. The outer doors closed. Before air was admitted to the inside, Sanford went suddenly still.

When they took him out of his suit he was apparently unconscious. He could not be roused. Freed, he drew his knees up to his chin in the position in which primitive peoples bury their dead. He seemed to sleep. Brent examined him carefully.

"Catatonia," he said distastefully. "He spent his life thinking he was smarter than anybody else—smarter, probably, than all the universe. He believed it. He couldn't face the fact that he was wrong. He couldn't stay conscious and not know it. So he's blacked out. He refuses to be anything unless he can be smartest. We'll have to do artificial feeding and all that until we can get him down to Earth to a hospital." He shrugged.

"We'd better report this down to Earth," Joe said. "By the way, better not describe our screen of tin cans on radio waves. Not even microwaves. It might leak. And we want to see if it works."

Just forty-two hours later they found out that it did work. A single rocket came climbing furiously out from Earth. It came from the night-side, and they could not see where it was launched, though they could make excellent guesses. They got a single guided missile ready to crash it if necessary.

It wasn't necessary. The bomb from Earth detonated 300 miles below the artificial satellite. Its proximity fuse, sending out small radar-type waves, had them reflected back by an empty sardine can thrown away from the Platform by Mike Scandia forty-some hours ago. The sardine can had been traveling in its own private orbit ever since. The effect of Mike's muscles had not been to send it back to Earth, but to change the center of the circular orbit in which it floated. Sometimes it floated above the Platform—that was on one side of Earth—and sometimes below it. It was about 300 miles under the Platform when it reflected urgent, squealing radar frequency waves to a complex proximity fuse in the climbing rocket. The rocket couldn't tell the difference between a sardine can and a Space Platform.

It exploded with a blast of pure brightness like that of the sun.

The Platform went on its monotonous round about the planet from which it had risen only weeks before. Sanford was strapped in a bunk and fed through a tube, and on occasion massaged and variously tended to keep him alive. The men on the Platform worked. They made telephoto maps of Earth. They took highly magnified, long-exposure photographs of Mars, pictures that could not possibly be made with such distinctness from the bottom of Earth's turbulent ocean of air.

There was a great deal of official business to be done. Weather observations of the form and distribution of cloud masses were an important matter. The Platform could make much more precise measurements of the solar constant than could be obtained below. The flickering radar was gathering information for studies of the frequency and size of meteoric particles outside the atmosphere. There was the extremely important project for securing and sealing in really good vacua in various electronic devices brought up by Joe and his crew in the supply ship.

But sometimes Joe managed to talk to Sally.

It was very satisfying to see her on the television screen in personal conversation. Their talk couldn't be exactly private, because it could be picked up elsewhere. It probably was. But she told Joe how she felt, and she wanted to read him the newspaper stories based on the reports Brent had sent down. Brent was in command of the Platform now that Sanford lay in a resolute coma in his bunk. But Joe discouraged such waste of time.

"How's the food?" asked Sally. "Are you people getting any fresh vegetables from the hydroponic garden?"

They were, and Joe told her so. The huge chamber in which sun-lamps glowed for a measured number of hours in each twenty-four produced incredibly luxuriant vegetation. It kept the air of the ship breathable. It even changed the smell of it from time to time, so that there was no feeling of staleness.

"And the cooking system's really good?" she wanted to know. Sally was partly responsible for that, too. "And how about the bunks?"

"I sleep now," Joe admitted.

That had been difficult. It was possible to get used to weightlessness while awake. One would slip, sometimes, and find himself suddenly tense and panicky because he'd abruptly noticed all over again that he was falling. But—and yet again Sally was partly responsible—the bunks were designed to help in that difficulty. Each bunk had an inflatable top blanket. One crawled in and settled down, and turned the petcock that inflated the cover. Then it held one quite gently but reassuringly in place. It was possible to stir and to turn over, but the feeling of being held fast was very comforting. With a little care about what one thought of before going to sleep, one could get a refreshing eight hours' rest. The bunks were luxury.

Sally said: "The date and time's a secret, of course, because it might be overheard, but there'll be another ship up before too long. It's bringing landing rockets for you to come back with."

"That's good!" said Joe. It would feel good to set foot on solid ground again. He looked at Sally and said eagerly, "We've got a date the evening I get back?"

"We've got a date," she said, nodding.

But it couldn't very well be a definite date. There were people with ideas that ran counter to plans for Joe to get back to Earth and a date with Sally Holt. The Space Platform was not admired uniformly by all the nations of Earth. The United States had built it because the United Nations couldn't, and one of the attractions of the idea had been that once it got out to space and was armed, peace must reign upon Earth because it could smack down anybody who made war.

The trouble was that it wasn't armed well enough. Six guided missiles couldn't defend it indefinitely. It looked as helpless as isolated Berlin did before the first airlift proved what men and planes could do in the way of transport. And the Platform's enemies didn't intend for it to be saved by a rocketlift. They would try to smash it before such a lift could get started.

A week after Joe got to it with the guided missiles, three rockets attacked. They went up from somewhere in the middle of the Pacific. One blew up 250 miles below the Platform. Another detonated 190 miles away. For safety's sake the third was crashed—at the cost of one guided missile—when it had come within 50 miles.

The screen of tin cans worked, but it wasn't thick enough. The occupants of the Platform went about hunting for sheet metal that could be spared. They pulled out minor partitions here and there, and went out on the surface and threw away thousands of small glittering scraps of metal in all directions.

Two weeks later, there was another attack. It could be calculated that Joe couldn't have carried up more than six guided missiles. There might be as few as two of them left. So eight rockets came up together—and the first of them went off 400 miles from the Platform. Only one got as close as 200 miles. No guided missiles were expended in defense.

The Platform's enemies tried once more. This time the rockets arched up above the Platform's orbit and dived on the satellite from above. There were two of them. They went off at 180 and 270 miles from the Platform. Joe's trash screen would not work on Earth, but in space it was an adequate defense against anything equipped with proximity fuses. It could be assumed that in a full-scale space-war nuts, bolts, rusty nails and beer bottle caps would become essential military equipment.

Three days after this last attack, a second supply ship took off from Earth. Lieutenant Commander Brown was a passenger. Its start was just like the one Joe's ship had made. Pushpots lifted it, jatos hurled it on, and then the furious, flaming take-off rockets drove it valiantly out toward the stars.

Joe's ship had been moved out of the landing lock and was moored against the Platform's hull. The second ship made contact in two hours and seventeen minutes from take-off. It arrived with its own landing rockets intact, and it brought a set of forty-foot metal tubes for Joe's ship to get back to Earth with. But those landing rockets and Lieutenant Commander Brown constituted all its payload. It couldn't bring up anything else.

And Lieutenant Commander Brown called a very formal meeting in the huge living space at the Platform's center. He stood up grandly in full uniform—and had to hook his feet around a chair leg to keep from floating absurdly in mid-air. This detracted slightly from the dignity of his stance, but not from the official voice with which he read two documents aloud.

The first paper detached Lieutenant Commander Brown from his regular naval duties and assigned him pro tem to service with the Space Exploration Project. The second was an order directing him to take command and assume direction of the Space Platform.

Having read his orders, he cleared his throat and said cordially, "I am honored to serve here with you. Frankly, I expect to learn much from you and to have very few orders to give. I expect merely to exercise such authority as experience at sea has taught me is necessary for a tight and happy ship. I trust this will be one."

He beamed. Nobody was impressed. It was perfectly obvious that he'd simply been sent up to acquire experience in space for later naval use, and that he'd been placed in command because it was unthinkable that he serve under anyone without official rank and authority. And he quite honestly believed that his coming, with experience in command, was a blessing to the Platform. In fact, there was no danger that this commander of the Platform would crack up under stress as Sanford had.

But it was too bad that he hadn't brought some long-range guided missiles with him.

Joe's ship had brought up twenty tons of cargo and twenty tons of landing rockets. The second ship brought up twenty tons of landing rockets for Joe, and twenty tons of landing rockets for itself. That was all. The second trip out to the Space Platform was a rescue mission and nothing else. Arithmetic wouldn't let it be anything else. And there couldn't be any idea of noble self-sacrifice and staying out at the Platform, either, because only four ships like Joe's had been begun, and only two were even near completion. Joe's had taken off the instant it was finished. The second had done the same. The second pair of spaceships wouldn't be ready for two months or more. The ships that could be used had to be used.

So, only thirty-six hours after the arrival of the second rocketship at the Platform, the two of them took off together to return to Earth. Joe's ship left the airlock first. Sanford was loaded in the cabin of the other ship as cargo. Lieutenant Commander Brown stayed out at the Platform to replace him.

Obviously, in order to get back to Earth they headed away from it in fleet formation. They pointed their rounded noses toward the Milky Way.

The upward course was an application of the principle that made the screen of tin cans and oddments remain about the Platform. Each of those small objects had had the Platform's own velocity and orbit. Thrown away from it, the centers of their orbits changed. In theory, the center of the Platform's orbit was the center of Earth. But the centers of the orbits of the thrown-away objects were pushed a few miles—twenty—fifty—a hundred—away from the center of Earth.

The returning space ships also had the orbit and speed of the Platform. They wanted to shift the centers of their orbits by very nearly 4,000 miles, so that at one point they would just barely graze Earth's atmosphere, lose some speed to it, and then bounce out to empty space again before they melted. Cooled off, they'd make another grazing bounce. After eight such bounces they'd stay in the air, and the stubby fins would give them a sort of gliding angle and controllability, while the landing rockets would let them down to solid ground. Or so it was hoped.

Meanwhile they headed out instead of in toward Earth. They went out on their steering-rockets only, using the liquid fuel that had not been needed for course correction on the way out. At 4,000 miles up, the force of gravity is just one-fourth of that at the Earth's surface. It still exists; it is merely canceled out in an orbit. The ships could move outward at less cost in fuel than they could move in.

So they went out and out on parallel courses, and the Platform dwindled behind them. Night flowed below until the hull of the artificial satellite shone brightly against a background of seeming sheer nothingness.

The twilight zone of Earth's shadow reached the Platform. It glowed redly, glowed crimson, glowed the deepest possible color that could be seen, and winked out. The ships climbed on, using their tiny steering rockets.

Nothing happened. The ships drew away from each other for safety. They were 50, then 60 miles apart. One glowed red and vanished in the shadow of the Earth. The other was extinguished in the same way. Then they went hurtling through the blackness of the night side of Earth. Microwaves from the ground played upon them—radar used by friend and foe alike—and the friendly radar guided tight-beam communicator waves to them with comforting assurance that their joint course and height and speed were exactly the calculated optimum. But they could not be seen at all.

When they appeared again they were still farther out from Earth than the Platform's orbit, but no farther from each other. And they were descending. The centers of their orbits had been displaced very, very far indeed.

Going out, naturally, the ships had lost angular speed as they gained in height. Descending, they gained in angular velocity as they lost height. They were not quite 30 miles apart as they sped with increasing, headlong speed and rushed toward the edge of the world's disk. When they were only 2,000 miles high, the Earth's surface under them moved much faster than it had on the way up. When they were only 1,000 miles high, the seas and continents seemed to flow past like a rushing river. At 500 miles, mountains and plains were just distinguishable as they raced past underneath. At 200 miles there was merely a churning, hurtling surface on which one could not focus one's eyes because of the speed of its movement.

They missed the solid surface of Earth by barely 40 miles. They were moving at a completely impossible speed. The energy of their position 4,000 miles high had been transformed into kinetic energy of motion. And at 40 miles there is something very close to a vacuum, compared to sea-level. But compared to true emptiness, and at the speed of meteors, the thin air had a violent effect.

A thin humming sound began. It grew louder. The substance of the ship was responding to the impact of the thin air upon it. The sound rose to a roar, to a bellow, to a thunderous tumult. The ship quivered and trembled. It shook. A violent vibration set up and grew more and more savage. The whole ship shook with a dreadful persistence, each vibration more monstrous, more straining, more ominous than before.

The four in the space ship cabin knew torture. Weight returned to them, weight more violent than the six gravities they had known for a bare fourteen seconds at take-off. But that, at least, had been smoothly applied. This was deceleration at a higher figure yet, and accompanied by the shaking of bodies which weighed seven times as much as ever before—and bodies, too, which for weeks past had been subject to no weight at all.

They endured. Nothing at all could be done. At so many miles per second no possible human action could be determined upon and attempted in time to have any effect upon the course of the ship. Joe could see out a quartzite port. The ground 40 miles below was merely a blur. There was a black sky overhead, which did not seem to stir. But cloud-masses rushed at express-train speed below him, and his body weighed more than half a ton, and the ship made the sound of innumerable thunders and shook, and shook and shook....

And then, when it seemed that it must fly utterly to pieces, the thunder diminished gradually to a bellow, and the bellow to a roar, and the roaring.... And the unthinkable weight oppressing him grew less.

The Earth was farther away and moving farther still. They were 100 miles high. They were 200 miles high....

There was no longer any sound at all, except their gaspings for breath. Their muscles had refused to lift their chests at all during the most brutal of the deceleration period.

Presently Joe croaked a question. He looked at the hull-temperature indicators. They were very, very high. He found that he was bruised where he had strapped himself in. The places where each strap had held his heavy body against the ship's vibrations were deeply black-and-blue.

The Chief said thickly: "Joe, somehow I don't think this is going to work. When do we hit again?"

"Three hours plus or minus something," said Joe, dry-throated. "We'll hear from the ground."

Mike said in a cracked voice: "Radar reports we went a little bit too low. They think we weren't tilted up far enough. We didn't bounce as soon as we should."

Joe unstrapped himself.

"How about the other ship?"

"It did better than we did," said Mike. "It's a good 200 miles ahead. Down at the Shed, they're recalculating for us. We'll have to land with six grazes instead of eight. We lost too much speed."

Joe went staggering, again weightless, to look out a port for the other ship. He should have known better. One does not spot an eighty-foot space ship with the naked eye when it is 200 miles away.

But he saw something, though for seconds he didn't know what it was.

Now the little ship was 300 miles high and still rising. Joe was dazed and battered by the vibration of the ship in the graze just past. The sister space ship hadn't lost speed so fast. It would be traveling faster. It would be leaving him farther behind every second. It was rising more sharply. It would rise higher.

Joe stared numbly out of a port, thinking confusedly that his hull would be dull red on its outer surface, though the heating had been so fast that the inner surfaces of the plating might still be cold. He saw the vast area which was the curve of the edge of the world. He saw the sunlight upon clouds below and glimpses of the surface of the Earth itself.

And he saw something rising out of the mists at the far horizon. It was a thread of white vapor. The other rocketship was a speck, a mote, invisible because of its size and distance. This thread of vapor was already 100 miles long, and it expanded to a column of whiteness half a mile across before it seemed to dissipate. It rose and rose, as if following something which sped upward. It was a rocket trail. The violence of its writhings proved the fury with which the rocket climbed.

It was on its way to meet the other space ship.

It did. Joe saw the thread of vapor extend and grow until it was higher than he was. He never saw the other ship, which was too small. But he saw the burst of flame, bright as the sun itself, which was the explosion of a proximity fuse bomb. He knew, then, that nothing but incandescent, radioactive gas remained of the other ship and its crew.

Then he saw the trail of the second rocket. It was rising to meet him.

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