Space Tug

9

But even at ten gravities' drive it takes time to travel 4,000 miles. At three, and coasting a great deal of the way, it takes much longer. The Platform circled Earth in four hours and a little more. Anything intending interception and rising straight up needed to start skyward long before the Platform was overhead. A three–g rocket would start while the Platform was still below the western horizon from its launching–spot. Especially if it planned to coast part of its journey—and a three–gravity rocket would have to coast most of the way.

So there was time. Coasting, the rising manned rocket would be losing speed. If it planned to go no higher than the Platform's orbit, its upward velocity would be zero there. If it were intercepted 500 miles down, it would be rising at an almost leisurely rate, and Joe and the Chief could check their Earthward plunge and match its rising rate.

This they did. But what they couldn't do was match its orbital velocity, which was zero. They had the Platform's eastward speed to start with—over 200 miles a minute. No matter how desperately they fired braking–rockets, they couldn't stop and maneuver around the rising control–ship. Inevitably they would simply flash past it in the fraction of an instant. To fire their tiny guided missiles on ahead would be almost to assure that they would miss. Also, the enemy ship was manned. It could fight back.

But Joe had been on the receiving end of one attack in space. It wasn't much experience, but it was more than anybody but he and his own crew possessed.

"Chief," said Joe softly into his helmet–mike, as if by speaking softly he could keep from being overheard, "get close enough to me to see what I do, and do it too. I can't tell you more. Whoever's running this rocket might know English."

There was a flaring of vapor in space. The Chief was using his steering–rockets to draw near.

Joe spun his little space wagon about, so that it pointed back in the direction from which he had come. He had four guided missiles, demolition type. Very deliberately, he fired the four of them astern—away from the rising rocket. They were relatively low–speed missiles, intended to blow up a robot ship that couldn't be hooked onto, because it was traveling too much faster or slower than the Platform it was intended to reach. The missiles went away. Then Joe faced about again in the direction of his prospective target. The Chief fumed—Joe heard him—but he duplicated Joe's maneuver. He faced his own eccentric vessel in the direction of its line of flight.

Then his fuming suddenly ceased. Joe's headphones brought his explosive grunt when he suddenly saw the idea.

"Joe! I wish you could talk Indian! I could kiss you for this trick!"

Brown's voice said anxiously: "I'm going to let that manned rocket have a couple more shots."

"Let us get by first," said Joe. "Then maybe you can use them on the bombs coming up."

He could see the trails of war–rockets on the way out from Earth. They were infinitesimal threads of vapor. They were the thinnest possible filaments of gossamer white. But they enlarged as they rose. They were climbing at better than two miles per second, now, and still increasing their speed.

But the arena in which this conflict took place was so vast that everything seemed to take place in slow motion. There was time to reason out not only the method of attack from Earth, but the excuse for it. If the Platform vanished from space, no matter from what cause, its enemies would announce vociferously that it had been destroyed by its own atomic bombs, exploding spontaneously. Even in the face of proof of murder, enemy nations would stridently insist that bombs intended for the enslavement of humanity—in the Platform—had providentially detonated and removed that instrument of war–mongering scoundrelly imperialists from the skies. There might be somebody, somewhere, who would believe it.

Joe and the Chief were steadied now nearly on a line to intercept the rising manned rocket. They had already fired their missiles, which trailed them. They went into battle, not prepared to shoot, but with their ammunition expended. For which there was excellent reason.

Something came foaming toward them from the nearby man–carrying rocket. It seemed like a side–spout from the column of vapor rising from Earth. Actually it was a guided missile.

"Now we dodge," said Joe cheerfully. "Remember the trick of this maneuvering business!"

It was simple. Speeding toward the rising assassin, and with his missiles rushing toward them, the relative speeds of the wagons and the missiles were added together. If the space wagons dodged, the missile operator had less time to swing his guided rockets to match the change of target course. And besides, the attacker hadn't made a single turn in space. Not yet. He might know that a rocket doesn't go where it's pointed, as a matter of theory. He might even know intellectually that the final speed and course of a rocket is the sum of all its previous speeds and courses. But he hadn't used the knowledge Joe and the Chief had.

Something rushed at them. They went into evasive action. And they didn't merely turn the noses of their space wagons. They flung them about end–for–end, and blasted. They used wholly different accelerations at odd angles. Joe shot away from Earth on steering rocket thrust, and touched off a four–three while he faced toward Earth's north pole, and halfway along that four–second rush he flipped his craft in a somersault and the result was nearly a right–angled turn. When the four–three burned out he set off a twelve–two, and halfway through its burning fired a three–two with it, so that at the beginning he had two gravities acceleration, then four gravities for three seconds, and then two again.

With long practice, a man might learn marksmanship in space. But all a man's judgment of speeds is learned on Earth, where things always, always, always move steadily. Nobody making his first space–flight could possibly hit such targets as Joe and the Chief made of themselves. The man in the enemy rocket was making his first flight. Also, Joe and the Chief had an initial velocity of 200 miles a minute toward him. The marksman in the rising rocket hadn't a chance. He fired four more missiles and tried desperately to home them in. But―

They flashed past his rising course. And then they were quite safe from his fire, because it would take a very long time indeed for anything he shot after them to catch up. But their missiles had still to pass him—and Joe and the Chief could steer them without any concern about their own safety or anything else but a hit.

They made a hit.

Two of the eight little missiles flashed luridly, almost together, where the radar–pips showed the rocket to be. Then there were two parts to the rocket, separating. One was small and one was fairly large. Another demolition–missile hit the larger section. Still another exploded as that was going to pieces. The smaller fragment ceased to be important. The explosions weren't atomic bombs, of course. They were only demolition–charges. But they demolished the manned rocket admirably.

Brown's voice came in the headphones, still tense. "You got it! How about the others?"

Joe felt a remarkable exhilaration. Later he might think about the poor devil—there could have been only one—who had been destroyed some 3,700 miles above the surface of the Earth. He might think unhappily of that man as a victim of hatred rather than as a hater. He might become extremely uncomfortable about this, but at the moment he felt merely that he and the Chief had won a startling victory.

"I think," he said, "that you can treat them with silent contempt. They won't have proximity fuses. Those friends of ours who want so badly to kill us have found that proximity fuses don't work. Unless one is on a collision course I don't think you need to do anything about them."

The Chief was muttering to himself in Mohawk, twenty miles away. Joe said:

"Chief, how about getting back to the Platform?"

The Chief growled. "My great–grandfather would disown me! Winning a fight and no scalp to show! Not even counting coup! He'd disown me!"

But Joe saw his rockets flare, away off against the stars.

The war rockets were very near, now. They still emitted monstrous jettings of thick white vapor. They climbed up with incredible speed. One went by Joe at a distance of little more than a mile, and its fumes eddied out to half that before they thinned to nothingness. They went on and on and on….

They burned out somewhere. It would be a long time before they fell back to Earth. Hours, probably. Then they would be meteors. They'd vaporize before they touched solidity. They wouldn't even explode.

But Joe and the Chief rode back to the Platform. It was surprising how hard it was to match speed with it again, to make a good entrance into the giant lock. They barely made it before the Platform made its plunge into that horrible blackness which was the Earth's shadow. And Joe was very glad they did make it before then. He wouldn't have liked to be merely astride a skinny framework in that ghastly darkness, with the monstrous blackness of the Abyss seeming to be trying to devour him.

Haney met them in the airlock. He grinned.

"Nice job, Joe! Nice job, Chief!" he said warmly. "Uh—the Lieutenant Commander wants you to report to him, Joe. Right away."

Joe cocked an eyebrow at him.

"What for?"

Haney spread out his hands. The Chief grunted. "That guy bothers me. I'll bet, Joe, he's going to explain you shouldn't've gone out when he didn't want you to. Me, I'm keeping away from him!"

The Chief shed his space suit and swaggered away, as well as anyone could swagger while walking on what happened to be the ceiling, from Joe's point of view. Joe put his space gear in its proper place. He went to the small cubbyhole that Brown had appropriated for the office of the Platform Commander. Joe went in, naturally without saluting.

Brown sat in a fastened–down chair with thigh grips holding him in place. He was writing. On Joe's entry, he carefully put the pen down on a magnetized plate that would hold it until he wanted it again. Otherwise it could have floated anywhere about the room.

"Mr. Kenmore," said Brown awkwardly, "you did a very nice piece of work. It's too bad you aren't in the Navy."

Joe said: "It did work out pretty fortunately. It's lucky the Chief and I were out practicing, but now we can take off when a rocket's reported, any time."

Brown cleared his throat. "I can thank you personally," he said unhappily, "and I do. But—really this situation is intolerable! How can I report this affair? I can't suggest commendation, or a promotion, or—anything! I don't even know how to refer to you! I am going to ask you, Mr. Kenmore, to put through a request that your status be clarified. I would imagine that your status would mean a rank—hm—about equivalent to a lieutenant junior grade in the Navy."

Joe grinned.

"I have—ah—prepared a draft you might find helpful," said Brown earnestly. "It's necessary for something to be done. It's urgent! It's important!"

"Sorry," said Joe. "The important thing to me is getting ready to load up the Platform with supplies from Earth. Excuse me."

He went out of the office. He made his way to the quarters assigned himself and his crew. Mike greeted him with reproachful eyes. Joe waved his hand.

"Don't say it, Mike! The answer is yes. See that the tanks are refilled, and new rockets put in place. Then you and Haney go out and practice. But no farther than ten miles from the Platform. Understand?"

"No!" said Mike rebelliously. "It's a dirty trick!"

"Which," Joe assured him, "I commit only because there's a robot ship from Bootstrap coming up any time now. And we'll need to pick it up and tow it here."

He went to the control–room to see if he could get a vision connection to Earth.

He got the beam, and he got Sally on the screen. A report of the attack on the Platform had evidently already gone down to Earth. Sally's expression was somehow drawn and haunted. But she tried to talk lightly.

"Derring–do and stuff, Joe?" she asked. "How does it feel to be a victorious warrior?"

"It feels rotten," he told her. "There must have been somebody in the rocket we blew up. He felt like a patriot, I guess, trying to murder us; But I feel like a butcher."

"Maybe you didn't do it," she said. "Maybe the Chief's bombs―"

"Maybe," said Joe. He hesitated. "Hold up your hand."

She held it up. His ring was still on it. She nodded. "Still there. When will you be back?"

He shook his head. He didn't know. It was curious that one wanted so badly to talk to a girl after doing something that was blood–stirring—and left one rather sickish afterward. This business of space travel and even space battle was what he'd dreamed of, and he still wanted it. But it was very comforting to talk to Sally, who hadn't had to go through any of it.

"Write me a letter, will you?" he asked. "We can't tie up this beam very long."

"I'll write you all the news that's allowed to go out," she assured him. "Be seeing you, Joe."

Her image faded from the screen. And, thinking it over, he couldn't see that either of them had said anything of any importance at all. But he was very glad they'd talked together.

The first robot ship came up some eight hours later—two revolutions after the television call. Mike was ready hours in advance, fidgeting. The robot ship started up while the Platform was over the middle of the Pacific. It didn't try to make a spiral approach as all other ships had done. It came straight up, and it started from the ground. No pushpots. Its take–off rockets were monsters. They pushed upward at ten gravities until it was out of atmosphere, and then they stepped up to fifteen. Much later, the robot turned on its side and fired orbital speed rockets to match velocity with the Platform.

There were two reasons for the vertical rise, and the high acceleration. If a robot ship went straight up, it wouldn't pass over enemy territory until it was high enough to be protected by the Platform. And—it costs fuel to carry fuel to be burned. So if the rocketship could get up speed for coasting to orbit in the first couple of hundred miles, it needn't haul its fuel so far. It was economical to burn one's fuel fast and get an acceleration that would kill a human crew. Hence robots.

The landing of the first robot ship at the Platform was almost as matter–of–fact as if it had been done a thousand times before. From the Platform its dramatic take–off couldn't be seen, of course. It first appeared aloft as a pip on a radar screen. Then Mike prepared to go out and hook on to it and tow it in. He was in his space suit and in the landing lock, though his helmet faceplate was still open. A loudspeaker boomed suddenly in Brown's voice: "Evacuate airlock and prepare to take off!"

Joe roared: "Hold that!"

Brown's voice, very official, came: "Withhold execution of that order. You should not be in the airlock, Mr. Kenmore. You will please make way for operational procedure."

"We're checking the space wagon," snapped Joe. "That's operational procedure!"

The loudspeaker said severely: "The checking should have been done earlier!"

There was silence. Mike and Joe, together, painstakingly checked over the very many items that had to be made sure. Every rocket had to have its firing circuit inspected. The tanks' contents and pressure verified. The air connection to Mike's space suit. The air pressure. The device that made sure that air going to Mike's space suit was neither as hot as metal in burning sunlight, nor cold as the chill of a shadow in space.

Everything checked. Mike straddled his red–painted mount. Joe left the lock and said curtly:

"Okay to pump the airlock. Okay to open airlock doors when ready. Go ahead."

Mike went out, and Joe watched from a port in the Platform's hull. The drone from Earth was five miles behind the Platform in its orbit, and twenty miles below, and all of ten miles off–course. Joe saw Mike scoot the red space wagon to it, stop short with a sort of cocky self–assurance, hook on to the tow–ring in the floating space–barge's nose, and blast off back toward the Platform with it in tow.

Mike had to turn about and blast again to check his motion when he arrived. And then he and Haney—Haney in the other space wagon—nudged at it and tugged at it and got it in the great spacelock. They went in after it and the lock doors closed.

Neither Mike nor Haney were out of their space suits when Kent brought Joe a note. A note was an absurdity in the Platform. But this was a formal communication from Brown.

"_From: Lt. Comdr. Brown

To: Mr. Kenmore

Subject: Cooperation and courtesy in rocket recovery vehicle launchings.

1. There is a regrettable lack of coordination and courtesy in the launching of rocket–recovery vehicles (space wagons) in the normal operation of the Platform.

2. The maintenance of discipline and efficiency requires that the commanding officer maintain overall control of all operations at all times.

3. Hereafter when a space vehicle of any type is to be launched, the commanding officer will be notified in writing not less than one hour before such launching.

4. The time of such proposed launching will be given in such notification in hours and minutes and seconds, Greenwich Mean Time.

5. All commands for launching will be given by the commanding officer or an officer designated by him._"

Joe received the memo as he was in the act of writing a painstaking report on the maneuver Mike had carried out. Mike was radiant as he discussed possible improvements with later and better equipment. After all, this had been a lucky landing. For a robot to end up no more than 30 miles from its target, after a journey of 4,000 miles, and with a difference in velocity that was almost immeasurable—such good fortune couldn't be expected as a regular thing. The space wagons were tiny. If they had to travel long distances to recover erratic ships coming up from Earth―

Joe forgot all about Lieutenant Commander Brown and his memo when the mail was distributed. Joe had three letters from Sally. He read them in the great living compartment of the Platform with its sixty–foot length and its carpet on floor and ceiling, and the galleries without stairs outside the sleeping cabins. He sat in a chair with thigh grips to hold him in place, and he wore a gravity simulation harness. It was necessary. The regular crew of the Platform, by this time, couldn't have handled space wagons in action against enemy manned rockets. Joe meant to stay able to take acceleration.

It was just as he finished his mail that Brent came in.

"Big news!" said Brent. "They're building a big new ship of new design—almost half as big as the Platform. With concreted metal they can do it in weeks."

"What's it for?" demanded Joe.

"It'll be a human base on the Moon," said Brent relievedly. "An expedition will start in six weeks, according to plan. As long as we're the only American base in space, we're going to be shot at. But a base on the Moon will be invulnerable. So they're going ahead with it."

Joe said hopefully:

"Any orders for me to join it?"

Brent shook his head. "We're to be loaded up with supplies for the Moon expedition. We're to be ready to take a robot ship every round. Actually, they can't hope to send us more than two a day for a while, but even that'll be eighty tons of supplies to be stored away."

The Chief grumbled, but somehow his grumbling did not sound genuine. "They're going to the Moon—and leave us here to do stevedore stuff?" His tone was odd. He looked at a letter he'd been reading and gave up pretense. He said self–consciously: "Listen, you guys…. My tribe's got all excited. I just got a letter from the council. They've been having an argument about me. Wanna hear?"

He was a little amused, and a little embarrassed, but something had happened to make him feel good.

"Let's have it," said Joe. Mike was very still in another chair. He didn't look up, though he must have heard. Haney cocked an interested ear.

The Chief said awkwardly, "You know—us Mohawks are kinda proud. We got something to be proud of. We were one of the Five Nations, when that was a sort of United Nations and all Europe was dog–eat–dog. My tribe had a big pow–wow about me. There's a tribe member that's a professor of anthropology out in Chicago. He was there. And a couple of guys that do electronic research, and doctors and farmers and all sorts of guys. All Mohawks. They got together in tribal council."

He stopped and flushed under his dark skin. "I wouldn't tell you, only you guys are in on it."

Still he hesitated. Joe found a curious picture forming in his mind. He'd known the Chief a long time, and he knew that part of the tribe lived in Brooklyn, and individual members were widely scattered. But still there was a certain remote village which to all the tribesmen was home. Everybody went back there from time to time, to rest from the strangeness of being Indians in a world of pale–skinned folk.

Joe could almost imagine the council. There'd be old, old men who could nearly remember the days of the tribe's former glory, who'd heard stories of forest warfare and zestful hunts, and scalpings and heroic deeds from their grandfathers. But there were also doctors and lawyers and technical men in that council which met to talk about the Chief.

"It's addressed to me," said the Chief with sudden clumsiness, "in the World–by–itself Canoe. That's the Platform here. And it says—I'll have to translate, because it's in Mohawk." He took a deep breath. "It says, 'We your tribesmen have heard of your journeyings off the Earth where men have never traveled before. This has given us great pride, that one of our tribe and kin had ventured so valiantly.'" The Chief grinned abashedly. He went on. "'In full assembly, the elders of the tribe have held counsel on a way to express their pride in you, and in the friends you have made who accompanied you. It was proposed that you be given a new name to be borne by your sons after you. It was proposed that the tribe accept from each of its members a gift to be given you in the name of the tribe. But these were not considered great enough. Therefore the tribe, in full council, has decreed that your name shall be named at every tribal council of the Mohawks from this day to the end of time, as one the young braves would do well to copy in all ways. And the names of your friends Joe Kenmore, Mike Scandia, and Thomas Haney shall also be named as friends whose like all young braves should strive to seek out and to be.'"

The Chief sweated a little, but he looked enormously proud. Joe went over to him and shook hands warmly. The Chief almost broke his fingers. It was, of course, as high an honor as could be paid to anybody by the people who paid it.

Haney said awkwardly, "Lucky they don't know me like you do, Chief. But it's swell!"

Which it was. But Mike hadn't said a word. The Chief said exuberantly:

"Did you hear that, Mike? Every Mohawk for ten thousand years is gonna be told that you were a swell guy! Crazy, huh?"

Mike said in an odd voice: "Yeah. I didn't mean that, Chief. It's fine! But I—I got a letter. I—never thought to get a letter like this."

He looked unbelievingly at the paper in his hands.

"Mash note?" asked the Chief. His tone was a little bit harsh. Mike was a midget. And there were women who were fools. It would be unbearable if some half–witted female had written Mike the sort of gushing letter that some half–witted females might write.

Mike shook his head, with an odd, quick smile.

"Not what you think, Chief. But it is from a girl. She sent me her picture. It's a—swell letter. I'm—going to answer it. You can look at her picture. She looks kind of—nice."

He handed the Chief a snapshot. The Chief's face changed. Haney looked over his shoulder. He passed the picture to Joe and said ferociously: "You Mike! You doggoned Don Juan! The Chief and me have got to warn her what kinda guy you are! Stealing from blind men! Fighting cops―"

Joe looked at the picture. It was a very sweet small face, and the eyes that looked out of the photograph were very honest and yearning. And Joe understood. He grinned at Mike. Because this girl had the distinctive look that Mike had. She was a midget, too.

"She's—thirty–nine inches tall," said Mike, almost stunned. "She's just two inches shorter than me. And—she says she doesn't mind being a midget so much since she heard about me. I'm going to write her."

But it would be, of course, a long time before there was a way for mail to get down to Earth.

It was a long time. Now it was possible to send up robot rockets to the Platform. They came up. When the second arrived, Haney went out to pull it in. Joe forgot to notify Brown, in writing, an hour before launching a rocket recovery vehicle (space wagon) according to paragraph 3 of the formal memo, nor the time of launching in hours, minutes, etc., by Greenwich Mean Time (paragraph 4), nor was the testing of all equipment made before moving it into the airlock. This was because the testing equipment was in the airlock, where it belonged. And the commands for launching were not given by Brown or an officer designated by him, because Joe forgot all about it.

Brown made a stormy scene about the matter, and Joe was honestly apologetic, but the Chief and Haney and Mike glared venomously.

The result was completely inconclusive. Joe had not been put under Brown's command. He and his crew were the only people on the Platform physically in shape to operate the space wagons, considering the acceleration involved. Brent and the others were wearing gravity simulators, and were building back to strength. But they weren't up to par as yet. They'd been in space too long.

So there was nothing Brown could do. He retreated into icily correct, outraged dignity. And the others hauled in and unloaded rockets as they arrived. They came up fast. The processes of making them had been improved. They could be made faster, heated to sintering temperature faster, and the hulls cooled to usefulness in a quarter of the former time. The production of space ship hulls went up to four a day, while the molds for the Moonship were being worked even faster. The Moonship, actually, was assembled from precast individual cells which then were welded together. It would have features the Platform lacked, because it was designed to be a base for exploration and military activities in addition to research.

But only twenty days after the recovery and docking of the first robot ship to rise, a new sort of ship entirely came blindly up as a robot. The little space wagons hauled it to the airlock and inside. They unloaded it—and it was no longer a robot. It was a modified hull designed for the duties of a tug in space. It could carry a crew of four, and its cargohold was accessible from the cabin. It had an airlock. More, it carried a cargo of solid–fuel rockets which could be shifted to firing racks outside its hull. Starting from the platform, where it had no effective weight, it was capable of direct descent to the Earth without spiralling or atmospheric braking. To make that descent it would, obviously, expend four–fifths of its loaded weight in rockets. And since it had no weight at the Platform, but only mass, it was capable of far–ranging journeying. It could literally take off from the Platform and reach the Moon and land on it, and then return to the Platform.

But that had to wait.

"Sure we could do it," agreed Joe, when Mike wistfully pointed out the possibility. "It would be good to try it. But unfortunately, space exploration isn't a stunt. We've gotten this far because—somebody wanted to do something. But―" Then he said, "It could be done and the United Nations wouldn't do it. So the United States had to, or—somebody else would have. You can figure who that would be, and what use they'd make of space travel! So it's important. It's more important than stunt flights we could make!"

"Nobody could stop us if we wanted to take off!" Mike said rebelliously.

"True," Joe said. "But we four can stand three gravities acceleration and handle any more manned rockets that start out here. We've lived through plenty more than that! But Brent and the others couldn't put up a fight in space. They're wearing harness now, and they're coming back to strength. But we're going to stay right here and do stevedoring—and fighting too, if it comes to that—until the job is done."

And that was the way it was, too. Of stevedoring there was plenty. Two robot ships a day for weeks on end. Three ships a day for a time. Four. Sometimes things went smoothly, and the little space wagons could go out and bring back the great, rocket–scarred hulls from Earth. But once in three times the robots were going too fast or too slow. The space wagons couldn't handle them. Then the new ship, the space tug, went out and hooked onto the robot with a chain and used the power it had to bring them to their destination. And sometimes the robots didn't climb straight. At least once the space tug captured an erratic robot 400 miles from its destination and hauled it in. It used some heavy solid–fuel rockets on that trip.

The Platform had become, in fact, a port in space, though so far it had had only arrivals and no departures. Its storage compartments almost bulged with fuel stores and food stores and equipment of every imaginable variety. It had a stock of rockets which were enough to land it safely on Earth, though there was surely no intention of doing so. It had food and air for centuries. It had repair parts for all its own equipment. And it had weapons. It contained, in robot hulls anchored to its sides, enough fissionable material to conduct a deadly war—which was only stored for transfer to the Moon base when that should be established.

And it had communication with Earth of high quality. So far the actual mail was only a one–way service, but even entertainment came up, and news. Once there was a television shot of the interior of the Shed. It was carefully scrambled before transmission, but it was a heartening sight. The Shed on the TV screen appeared a place of swarming activity. Robot hulls were being made. They were even improved, fined down to ten tons of empty weight apiece, and their controls were assembly line products now. And there was the space flight simulator with men practicing in it, although for the time being only robots were taking off from Earth. And there was the Moonship.

It didn't look like the Platform, but rather like something a child might have put together out of building blocks. It was built up out of welded–together cells with strengthening members added. It was 60 feet high from the floor and twice as long, and it did not weigh nearly what it seemed to. Already it was being clad in that thick layer of heat insulation it would need to endure the two–week–long lunar night. It could take off very soon now.

The pictured preparations back on Earth meant round–the–clock drudgery for Joe and the others. They wore themselves out. But the storage space on the Platform filled up. Days and weeks went by. Then there came a time when literally nothing else could be stored, so Joe and his crew made ready to go back to Earth.

They ate hugely and packed a very small cargo in their ship. They picked up one bag of mail and four bags of scientific records and photographs which had only been transmitted by facsimile TV before. They got into the space tug. It floated free.

"You will fire in ten seconds," said a crisp voice in Joe's headphones. "Ten … nine … eight … seven … six … five … four …three … two … one … fire!"

Joe crooked his index finger. There was an explosive jolt. Rockets flamed terribly in emptiness. The space tug rushed toward the west. The Platform seemed to dwindle with startling suddenness. It seemed to rush away and become lost in the myriads of stars. The space tug accelerated at four gravities in the direction opposed to its orbital motion.

As the acceleration built up, it dropped toward Earth and home like a tumbled stone.