THE NEXT MORNING Burke ignored the trouble they had had; he made no mention of it. He was even moderately cooperative about sharing the 'fresher. But Matt was glad to hear the call to breakfast.

Table 147 was not where it should be. Puzzled, Matt moved down the line until he found a table marked "147-149," with Cadet Sabbatello in charge. He found a place and sat down, to find himself sitting next to Pierre Armand. "Well! Pete!" he greeted him. "How are things going?"

"Glad to see you, Matt. Well enough, I guess." His tone seemed doubtful.

Matt looked him over. Pete seemed-"dragged through a knothole" was the phrase Matt settled on. He was about to ask what was wrong when Cadet Sabbatello rapped on the table. "Apparently," said the cadet, "some of you gentlemen have forgotten my advice last night, to eat sparingly this morning. You are about to go over the bumps today-and ground-hogs have been known to lose their breakfasts as well as their dignity."

Matt looked startled. He had intended to order his usual lavish breakfast; he settled for milk toast and tea. He noticed that Pete had ignored the cadet's advice; he was working on a steak, potatoes, and fried eggs-whatever ailed Pete, Matt decided, it had not affected his appetite.

Cadet Sabbatello had also noticed it. He leaned toward Pete. "Mister, uh-"

"Armand, sir," Pete answered between bites.

"Mr. Armand, either you have the digestion of a Martian sandworm, or you thought I was joking. Don't you expect to be dropsick?"

"No, sir."

"No?"

"You see, sir, I was born on Ganymede."

"Oh! I beg your pardon. Have another steak. How are you doing?"

"Pretty well, on the whole, sir."

"Don't be afraid to ask for dispensations. You'll find that everyone around here understands your situation."

"Thank you, sir."

"I mean it. Don't play 'iron man.' There's no sense in it."

After breakfast, Matt fell in step with Armand. "Say, Pete, I see why Oscar carried your bag yesterday. Excuse me for being a stupe."

Pete looked self-conscious. "Not at all. Oscar has been looking out for me-I met him on the trip down from Terra Station."

Matt nodded. "I see." He had no expert knowledge of interplanetary schedules, but he realized that Oscar, coming from Venus, and Pete, coming from one of Jupiter's moons, would-have to change ships at the artificial satellite of Earth called Terra Station, before taking the shuttle rocket down.

It accounted for the two boys being well acquainted despite cosmically different backgrounds. "How do you feel?" he went on.

Pete hesitated. "As a matter of fact, I feel as if I were wading in quicksand up to my neck. Every move is an effort."

"Gee, that's too bad! Just what is the surface gravity on Ganymede? About one-third V isn't it?"

"Thirty-two per cent. Or from my point of view, everything here weighs three times as much as it ought to. Including me."

Matt nodded. "As if two other guys were riding on you, one on your shoulders, and one on your back."

"That's about it. The worst of it is, my feet hurt all the time. I'll get over it-"

"Sure you will!

"-since. I'm of Earth ancestry and potentially just as strong as my grandfather was. Back home, I'd been working out in the centrifuge the last couple of earth-years. I'm a lot stronger than I used to be. There's Oscar." Matt greeted Oscar, then hurried to his room to phone his father in private.

A copter transport hopped Matt and some fifty other candidates to the site of the variable acceleration test-in cadet slang, the "Bumps." It was west of the base, in the mountains, in order to have a sheer cliff for free fall. They landed on a loading platform at the edge of this cliff and joined a throng of other candidates. It was a crisp Colorado morning. They were near the timberline; gaunt evergreens, twisted by the winds, surrounded the clearing.

From a building just beyond the platform two steel skeletons ran vertically down the face of the two-thousand-foot cliff. They looked like open frames for elevators, which one of them was. The other was a guide for the testing car during the drop down the cliff.

Matt crowded up to the rail and leaned over. The lower ends of the skeleton frameworks disappeared, a dizzy distance below, in the roof of a building notched into the sloping floor of the canyon. He was telling himself that he hoped the engineer who had designed the thing knew what he was doing when he felt a dig in the ribs. It was Tex. "Some roller coaster, eh, Matt?"

"Hi, Tex. That's an understatement if I ever heard one."

The candidate on Matt's left spoke up. "Do you mean to say we ride down that thing?"

"No less," Tex answered. "Then they gather the pieces up in a basket and haul 'em up the other one."

"How fast does it go?"

"You'll see in a mom- Hey! Thar she blows!"

A silvery, windowless car appeared inside one guide frame, at its top. It poised for a split second, then dropped. It dropped and dropped and dropped, gathering speed, until it disappeared with what seemed incredible velocity- actually about two hundred and fifty miles per hour-into the building below. Matt braced himself for the crash. None came, and he caught his breath.

Seconds later the car reappeared at the foot of the other framework. It seemed to crawl; actually it was accelerating rapidly during the first half of the climb. It passed from view into the building at the top of the cliff.

"Squad nine!" a loudspeaker bawled behind them.

Tex let out a sigh "Here I go, Matt," he said. "Tell mother my last words were of her. You can have my stamp collection." He shook hands and walked away.

The candidate who had spoken before gulped; Matt saw that he was quite pale. Suddenly he took off in the same direction but did not line up with the squad; instead he went up to the cadet mustering the squad and spoke to him, briefly and urgently. The cadet shrugged and motioned him away from the group.

Matt found himself feeling sympathetic rather than contemptuous.

His own test group was mustered next. He and his fellows were conducted into the upper building, where a cadet explained the test: "This test examines your tolerance for high acceleration, for free fall or weightlessness, and for violent changes in acceleration. You start with centrifugal force of three gravities, then all weight is removed from you as the car goes over the cliff. At the bottom the car enters a spiraling track which reduces its speed at deceleration of three gravities. When the car comes to rest, it enters the ascending tower; you make the climb at two gravities, dropping to one gravity, and momentarily to no weight, as the car reaches the top. Then the cycle is repeated, at higher accelerations, until each of you has reacted. Any questions?"

Matt asked, "How long is the free fall, sir?"

"About eleven seconds. We would increase it, but to double it would take four times as high a cliff. However, you will find this one high enough." He smiled grimly.

A timid voice asked, "Sir, what do you mean by 'react'?"

"Any of several things-hemorrhage, loss of consciousness."

"It's dangerous?"

The cadet shrugged. "What isn't? There has never been any mechanical failures. Your pulse, respiration, blood pressure, and other data are telemetered to the control room. We'll try not to let you die under test."

Presently he led them out of the room, down a passage and through a door into the test car. It had pendulum seats, not unlike any high-speed vehicle, but semi-reclining and heavily padded. They strapped down and medical technicians wired them for telemetering their responses. The cadet inspected, stepped out and returned with an officer, who repeated the inspection. The cadet then distributed "sick kits"-cloth bags of double thickness to be tied and taped to the mouth, so that a person might retch without inundating his companions. This done, he asked, "Are you all ready?" Getting no response, he went out and closed the door.

Matt wished that he had stopped him before it was too late.

For a long moment nothing happened. Then the car seemed to incline; actually, the seats inclined as the car started to move and picked up speed.

The seats swung back to the at-rest position but Matt felt himself getting steadily heavier and knew thereby that

they were being centrifuged. He pressed against the pads, arms leaden, legs too heavy to move.

The feeling of extra weight left him, he felt his normal weight again, when suddenly that, too, was taken from him. He surged against the safety belts.

His stomach seemed to drop out of him. He gulped and swallowed; his breakfast stayed down. Somebody yelled, "We're falling!" It seemed to Matt the most unnecessary statement he had ever heard.

He set his jaw and braced himself for the bump. It did not come-and still his stomach seemed trying to squirm its way out of his body. Eleven seconds? Why, he had been falling more than eleven seconds already. What had gone wrong?

And still they fell, endlessly.

And fell.

Then he was forced back against the pads. The pressure increased smoothly until he was as heavy as he had been just before the drop. His abused stomach tried to retch but the pressure was too much for it.

The pressure eased off to normal weight. A short while later the car seemed to bounce and momentarily he was weightless, while his insides grabbed frantically for anchorage. The feeling of no weight lasted only an instant; he sagged into the cushions.

The door was flung open; the cadet strode in, followed by two medical technicians. Someone yelled, "Let me out of here! Let me out of here!" The cadet paid no attention but went to the seat in front of Matt. He unstrapped the occupant and the two medical assistants carried him out. His head lolled loosely as they did so. The cadet then went to the candidate who was kicking up the fuss, unstrapped him, and stepped back. The boy got up, staggered, and shuffled out.

"Anyone need a fresh sick kit?" There were muffled responses. Working swiftly, the cadet helped those who needed it. Matt felt weakly triumphant that his own kit was still clean.

"Stand by for five gravities," commanded the cadet. He made them answer to their names, one by one. While he was doing so another boy started clawing at his straps. Still calling the roll, the cadet helped him free and let him leave. He followed the lad out the door and shut it.

Matt felt himself tensing unbearably. He was relieved when the pressure took hold-but only momentarily, for he found that five gravities were much worse than three. His chest seemed paralyzed, he fought for air.

The giant pressure lifted-they were over the edge again, falling. His mistreated stomach revenged itself at once; he was sorry that he had eaten any breakfast at all.

They were still falling. The lights went out-and someone screamed. Falling and still retching, Matt was sure that the blackness meant some sort of accident; this time they would crash-but it did not seem to matter.

He was well into the black whirlpool of force that marked the deceleration at the bottom before he realized that he had come through without being killed. The thought brought no particular emotion; breathing at five gravities fully occupied him. The ride up the cliff, at double weight dropping off to normal weight, seemed like a vacation-except that his stomach protested when they bounced to a stop.

The lights came on and the cadet re-entered the room. His gaze stopped at the boy on Matt's right. The lad was bleeding at his nose and ears. The candidate waved him away feebly. "I can take it," he protested. "Go on with the test."

"Maybe you can," the cadet answered, "but you are through for today." He added, "Don't feel bad about it. It's not necessarily a down check."

He inspected the others, then called in the officer. The two held a whispered consultation over one boy, who was then half led, half carried from the test chamber. "Fresh sick kits?" asked the cadet.

"Here," Matt answered feebly. The change was made, while Matt vowed to himself never to touch milk toast again.

"Seven gravities," announced the cadet. "Speak up, or stand by." He called the roll again. Matt was ready to give up, but he heard himself answer "ready" and the cadet was gone before he could make up his mind. There were only six of them left now.

It seemed to him that the lights were going out again, gradually, as the weight of his body built up to nearly a thousand pounds. But the lights "came on" again as the car dropped over the cliff; he realized dully that he had blacked out.

He had intended to count seconds on this fall to escape the feeling of endless time, but he was too dazed. Even the disquiet in his middle section seemed remote. Falling-falling-

Again the giant squeezed his chest, drained the blood from his brain, and shut the light from his eyes. The part that was Matt squeezed out entirely. ...

"How do you feel?" He opened his eyes, saw a double image, and realized dimly that the cadet was leaning over him. He tried to answer. The cadet passed from view; he felt someone grasping him; he was being lifted and carried.

Someone wiped his face with a wet, cold towel. He sat up and found himself facing a nurse. "You're all right now," she said cheerfully. "Keep this until your nose stops bleeding." She handed him the towel. "Want to get up?"

"Yes, I think so."

"Take my arm. We'll go out into the air."

Out on the loading platform Matt sat in the sunshine, dabbling at his nose and regaining his strength. He could hear sounds of excitement from the rail behind each time the car dropped. He sat there, soaking in the sun and wondering whether or not he really wanted to be a spaceman.

"Hey, Matt." It was Tex, looking pale and not too sure of himself. There was a blood stain down the front of his coverall.

"Hello, Tex. I see you've had it."

"Yeah."

"How many g's?"

"Seven."

"Same here. What do you think of it?"

"Well-" Tex seemed at a loss. "I wish my Uncle Bodie could have tried it. He wouldn't talk so much about the time he rassled the grizzly."

There were many vacant seats at lunch. Matt thought about those who had gone-did they mind being "bumped out," or were they relieved?

He was hungry but ate little, for he knew what was ahead that afternoon- rocket indoctrination. He had looked forward to this part of the schedule most eagerly. Space flight! Just a test jump, but the real thing nevertheless. He had been telling himself that, even if he failed, it would be worth it to get this first flight.

Now he was not sure; the "bumps" had changed his viewpoint. He had a new, grim respect for acceleration and he no longer thought drop-sickness funny; instead he was wondering whether or not he would ever get adjusted to free fall. Some never did, he knew.

His test group was due in Santa Barbara Field at fourteen-thirty. He had a long hour to kill with nothing to do but fret. Finally it was time to go underground, muster, and slidewalk out to the field.

The cadet in charge led them up to the surface into a concrete trench about four feet deep. Matt blinked at the sunlight. His depression was gone; he was anxious to start. On each side and about two hundred yards away were training rockets, lined up like giant birthday candles, poised on their fins with sharp snouts thrusting against the sky.

"If anything goes wrong," the cadet said, "throw yourself flat in the trench. Don't let that get your goat-I'm required to warn you.

"The jump lasts nine minutes, with the first minute and a half under power. You'll feel three gravities, but the acceleration is only two gravities, because you are still close to the Earth.

"After ninety seconds you'll be travelling a little faster than a mile a second and you will coast on up for the next three minutes for another hundred miles to an altitude of about one hundred fifty miles. You fall back toward the earth another three minutes, brake your fall with the jet and ground at the end of the ninth minute.

"A wingless landing on an atmosphere planet with gravity as strong as that of Earth is rather tricky. The landing will be radar-robot controlled, but a human pilot will stand by and check the approach against the flight plan. He can take over if necessary. Any questions?"

Someone asked, "Are these atomic-powered ships?"

The cadet snorted. "These jeeps? These are chemically powered, as you can see from the design. Monatomic hydrogen. They are much like the first big rockets ever built, except that they have variable thrust, so that the pilot and the passengers won't" be squashed into strawberry jam as the mass- ratio drops off."

A green signal flare arched up from the control tower. "Keep your eyes on the second rocket from the end, on the north," advised the cadet.

There was a splash of orange flame, sun bright, at the base of the ship. "There she goes!"

The ship lifted majestically, and poised for an instant, motionless as a hovering helicopter. The noise reached Matt, seemed to press against his chest. It was the roar of an impossibly huge blowtorch. A searchlight in the tower blinked, and the ship mounted, up and up, higher and faster, its speed increasing with such smoothness that it was hard to realize how fast it was going-except that the roar was gone. Matt found himself staring straight at the zenith, watching a dwindling artificial sun, almost as dazzling as Sol himself.

Then it was gone. Matt closed his mouth and started to look away, when his attention was seized by the ice trail left as the rocket sliced its way through the outer atmosphere. White and strange, it writhed like a snake with a broken back. Under the driving force of the many-hundred-miles-an-hour winds of that far altitude it twisted visibly as he watched.

"That's all!" the cadet shouted. "We can't wait for the landing."

They went underground, down a corridor, and entered an elevator. It went up right out of the ground and into the air, supported by a hydraulic piston. It mounted close by the side of a rocket ship; Matt was amazed to see how large it was close up.

The elevator stopped and its door let down drawbridge fashion into the open hatch in the rocket's side. They trooped across; the cadet raised the bridge and went down again.

They were in a conical room. Above them the pilot lay in his acceleration rest. Beside them, feet in and head out, were acceleration couches for passengers. "Get in the bunks!" shouted the pilot. "Strap down."

Ten boys jostled one another to reach the couches. One hesitated. "Uh, oh, Mister!" he called out.

"Yes? Get in your couch."

"I've changed my mind. I'm not going."

The pilot used language decidedly not officerlike and turned to his control board. 'Tower! Remove passenger from number nineteen." He listened, then said, "Too late to change the flight plan. Send up mass." He shouted to the waiting boy, "What do you weigh?"

"Uh, a hundred thirty-two pounds, sir."

"One hundred and thirty-two pounds and make it fast!" He turned back to the youngster. "You better get off this base fast, for if I have to skip my take- off I'll wring your neck."

The elevator climbed into place presently and three cadets poured across. Two were carrying sandbags, one had five lead weights. They strapped the sandbags to the' vacant couch, and clamped the weights to its sides. "One thirty-two mass," announced one of the cadets.

"Get going," snapped the pilot and turned back to the board.

"Don't blow your tubes, Harry," advised the cadet addressed. Matt was amazed, then decided the pilot must be a cadet, too. The three left, taking with them the boy; the hatch door shut with a whish.

"Stand by to raise!" the pilot called out, then looked down to check his passengers. "Passengers secure, nineteen," he called to the tower. "Is that confounded elevator clear?"

There was silence as the seconds trickled away.

The ship shivered. A low roar, muffled almost below audibility, throbbed in Mart's head. For a moment he felt slightly heavy, the feeling passed, then he was pressed strongly against the pads.

Matt was delighted to find that three gravities were not bad, flat on his back as he was. The minute and a half under power stretched out; there was nothing to hear but the muted blast of the reactor, nothing to see but the sky through the pilot's port above.

But the sky was growing darker. Already it was purple; as he watched it turned black. Fascinated, he watched the stars come out.

"Stand by for free fall!" the pilot called out, using an amplifier. "You'll find sick kits under each pillow. If you need 'em, put 'em on. I don't want to have to scrape it off the port."

Matt fumbled with heavy fingers under his head, found the kit. The sound of the jet died away, and with it the thrust that had kept them pinned down. The pilot swung out of his rest and floated, facing them. "Now look, sports - we've got six minutes. You can unstrap, two at a time and come up for a look-see. But get this: Hang oh tight. Any man who starts floating free, or skylarking, gets a down check." He pointed to a boy. "You-and the next guy."

The "next guy" was Matt. His stomach was complaining and he felt so wretched that he did not really want the privilege offered-but his face was at stake; he clamped his jaws, swallowed the saliva pouring into his mouth, and unstrapped.

Free, he clung to one strap, floating loosely, and tried to get his bearings. It was curiously upsetting to have no up-and-down; it made everything swim- he had trouble focusing his eyes. "Hurry up there!" he heard the pilot shout, "or you'll miss your turn."

"Coming, sir."

"Hang on-I'm going to turn the ship." The pilot unclutched his gyros and cut in his processing flywheels. The ship turned end over end. By the time Matt worked his way to the control station, moving like a cautious and elderly monkey, the rocket was pointed toward Earth.

Matt stared out at the surface, nearly a hundred miles below and still receding. The greens and browns seemed dark by contrast with the white dazzle of clouds. Off to the left and right he could see the inky sky, stabbed with stars. "That's the Base, just below," the pilot was saying. "Look sharp and you can make out Hayworth Hall, maybe, by its shadow."

It did not seem "just below" to Matt; it seemed "out"- or no direction at all. It was disquieting. "Over there-see? -is the crater where Denver used to be. Now look south-that brown stretch is Texas; you can see the Gulf beyond it."

"Sir," asked Matt, "can we see Des Moines from here?"

"Hard to pick out. Over that way-let your eye slide down the Kaw River till it strikes the Missouri, then up river. That dark patch-that's Omaha and Council Bluffs. Des Moines is between there and the horizon." Matt strained his eyes, trying to pick out his home. He could not be sure- but he did see that he was staring over the bulge of the Earth at a curved horizon; he was seeing the Earth as round. "That's all," ordered the pilot. "Back to your bunks. Next pair!"

He was glad to strap a belt across his middle. The remaining four minutes or so stretched endlessly; he resigned himself to never getting over space sickness. Finally the pilot chased the last pair back, swung ship jet toward Earth, and shouted, "Stand by for thrust-we're about to ride her down on her tail!"

Blessed weight pressed down on him and his stomach stopped complaining. The ninety seconds of deceleration seemed longer; it made him jumpy to know that the Earth was rushing up at them and not be able to see it. But at last there came a slight bump and his weight dropped suddenly to normal. "Grounded," announced the pilot, "and all in one piece. You can unstrap, sports."

Presently a truck arrived, swung a telescoping ladder up to the hatch, and "they climbed down. On the way back they passed a great unwieldy tractor, crawling out to retrieve the rocket. Someone stuck his head out of the tractor. "Hey! Harry-why didn't you land it in Kansas?"

Their pilot waved at the speaker. "Be grateful I didn't!"

Matt was free until mess; he decided to return to the observation trench; he still wanted to see a ship land on its jet. He had seen winged landings of commercial stratosphere rockets, but never a jet landing.

Matt had just found a vacant spot at the trench when a shout went up-a ship was coming in. It was a ball of flame, growing in the sky, and then a

pillar of flame, streaking down in front of him. The streamer of fire brushed the ground, poised like a ballet dancer, and died out. The ship was down.

He turned to a candidate near him. "How long till the next one?"

"They've come in about every five minutes. Stick around."

Presently a green flare went up from the control tower and he looked around, trying to spot the ship about to take off, when another shout caused him to turn back. There again was a ball of fire in the sky, growing.

Unbelievably, it went out. He stood there, stupefied- to hear a cry of "Down! Down, everybody! Flat on your faces!" Before he could shake off his stupor, someone tackled him and threw him.

He was rocked by a sharp shock, on top of it came the roar of an explosion. Something snatched at his breath.

He sat up and looked around. A cadet near him was peering cautiously over the parapet. "Allah the Merciful," he heard him say softly.

"What happened?"

"Crashed in. Dead, all dead." The cadet seemed to see him for the first time. "Get back to your quarters," he said sharply.

"But how did it happen?"

"Never mind-this is no time for sightseeing." The cadet moved down the line, clearing out spectators.