Chapter II: Part 2

Sue eagerly went to the eyepiece. The telescope brought a city into very close range. It seemed as if she had only to reach out a finger to touch the tall spire of a building. Suddenly she gasped. She knew that building! It was the home office of her father’s place of work. The city was Little Rock, Arkansas, their own home!

“Steve, look!” she said excitedly to her brother and let him see for himself.

Steve was as thrilled as Sue. Together they moved the telescope lens over all the familiar spots of the great space city, which in this day had a million population. They were able to locate the wee speck that was their own home in the suburbs.

“I can almost see Mom hanging out the wash in the yard!” Steve said with a grin.

Before the children were through looking, they noticed several black hazy spots in different parts of the state.

“What are these, Dad?” Steve asked, showing them to his father.

“They’re tornadoes, Son,” Mr. Shannon replied. “There seems to be an unusually large crop of them this season. There are even some close to Little Rock. The Weather Control Bureau here has a way of dealing with them, though. They do many skillful things in Weather Control. They can make it rain in dry parts of the world and even melt snow drifts in blizzard areas.”

“What can they do about a tornado?” Steve asked.

“When one threatens a city they fire a guided missile—a bomb—that breaks up the twister before it can do any harm. We’ll visit the Weather Control Bureau as soon as we’ve been to the hub of the Wheel.”

Mr. Shannon led them out of the Military Lookout Room. Steve and Sue then found a job of climbing facing them. In order to reach the hub, they had to go through one of the spokes leading into the center of the Wheel. The children saw before them a nylon ladder stretching as far as they could see down a long corridor.

“Let’s start climbing,” their father said.

“Why can’t we just walk along the hall,” Sue asked, “instead of doing it the hard way?”

“You’re forgetting that the Wheel is always throwing you outward as it spins,” Mr. Shannon said. “If you tried to walk down the spoke it would be like trying to walk against a hurricane. For this reason, you two must be careful not to lose your grip on the ladder or you’ll be flung down the corridor against the rim.”

The three began climbing hand over hand along the ladder. They got along very well until Sue suddenly became dizzy and lost her hold. She screamed as she began flying down the corridor. Steve’s heart nearly stopped beating for a moment. He heard his father calling out loudly in a frantic voice: “Grab the ladder, Sue! Grab the ladder!”

At first Sue did not seem to hear and kept hollering in fright. Then she understood and reached out wildly with her hands for the nylon ladder as she swept along. One hand seized a piece of it and she held on for dear life, her body still hanging in mid-air as the force of the turning Wheel kept trying to throw her outward.

“Hold on, Sue!” her father called. “We’re coming!”

He and Steve swiftly crawled along the ladder to the spot where Sue was clinging with one hand.

“Hurry!” she cried. “I can’t hang on much longer!”

Just as she was about to let go, Steve reached her and held on to her with his free hand. Then his father lent his help and Sue was safe. She sobbed for a moment from the fright she had had and Mr. Shannon suggested that they go back to the rim where they would be safe again. Both children agreed, for they had suddenly lost all interest in the hub.

By the time they got to the Weather Control Bureau they found more worry awaiting them. Men were hustling about the huge room with serious looks on their faces. One of them was looking into the eyepiece of a large machine that was pointed out the window down onto Earth.

“What’s wrong?” Mr. Shannon asked one of the men.

“A tornado is headed for Little Rock, Arkansas!” was the shocking reply. “I hope our missile scores a hit, but it isn’t going to be easy because the Wheel has already moved past the United States!”

“The missile’s _got_ to hit!” Steve burst out. “Our home and Mom are there!”

“Yes, it’s simply _got_ to!” Sue added tearfully.

The Shannons had to stand helplessly on the side as the tornado fighters went to work. The missile gun was in another part of the Wheel, but the orders for firing it would leave this room by radio.

“Oh, why couldn’t Mom have come with us?” Sue asked. “She would have been safe here!”

Steve felt his whole body tensing like a wound spring. The perspiration was beading his forehead and his knees were weak. On his father’s face there was a dark look and Steve saw that his big hands were opening and closing.

“Twenty seconds to go before firing,” the man at the machine said slowly over the radio mike on his chest. “Steady. Eighteen—seventeen—”

“Why don’t they hurry?” Sue cried. “They’re so slow!”

“They have to do it a certain way,” Mr. Shannon answered. “They know what they’re doing, Honey. Don’t be afraid.”

But she _was_ afraid. And so was Steve. And her father, too. Everyone in the room was afraid because no one could say whether the tornado could be destroyed before it hit the city or not.

“Eight—seven—six—” droned the unhurried voice of the operator.

The Shannons hardly dared breathe for fear of disturbing the man at the machine. Steve felt Sue’s body quivering next to him. It seemed as if the seconds were dragging on endlessly.

“Three—two—one—FIRE!”

Steve felt nothing but he knew the tornado bomb was on its way, speeding hundreds of miles a second Earthward.

For long, awfully long, moments after the operator had said, “Fire!” the Shannons waited for him to speak again. He kept looking calmly through the eyepiece of the machine as though just studying the stars. Then at last they saw a smile spread over his face and he said to everyone in the room, “It’s a hit! Little Rock is safe!”

Sue and Steve whooped as if it were Christmas morning. Where a minute before they had been greatly worried, now they were happy as they never believed they could be.

“Whew!” Mr. Shannon sighed. “I’m afraid I’ve had enough excitement to last me a lifetime!”

“Not me, Dad,” Steve said, as the fire of adventure began to glow again in his eyes. “I won’t be satisfied until I’ve seen what lies beyond the Wheel in the Sky!”

_DANGER ON THE ICE CANAL_

Steve and Sue Shannon were at Mars Port No. 13. This was one of the many colonies on the planet Mars where Earth scientists were carrying on work. It was a town of plastic tops, called domes, that were clear as glass. The town was at the center of three canals that led outward into the red desert.

The Shannon twins were now touring the largest dome with Biff Warren, who worked for their father’s space cargo company. Suddenly their tour brought them to a large cafeteria where many of the workers were eating.

“Umm!” Sue exclaimed. “Smell that turkey!”

“Yeah!” Steve said. “It sure makes your mouth water, doesn’t it?”

“Which reminds me,” Biff said, looking at his watch. “We’ll have to finish up our sightseeing pretty soon. The quicker we get back to your father’s ship, the quicker we can have our own turkey feast!”

“I can hardly wait for that!” Sue sighed, as the wonderful smell of the holiday meal kept tickling her nose.

When Thanksgiving dinner was finished aboard the big space freighter that had brought the children to Mars, the ship would take off into space. But before that, Biff, Sue and Steve would have to go twenty miles back down the ice canal to reach the ship.

Biff had become a close friend of the young Shannons, having made trips with them to other ports in space. Sue liked Biff because of his quick smile and gentle patience. Steve liked him because he was all that Steve would like to be some day himself—a fearless, bold spaceman.

They finished up their tour of the dome. They saw the room where giant machines made oxygen out of chemicals and blew it through the building so that there was fresh air to breathe all the time. And they saw the astronomy hall far up on top of the dome where scientists could see the heavens through the thin atmosphere much clearer than they could from Earth.

“Isn’t it about time for the fuel rocket to be shot off, Biff?” Steve asked.

Biff nodded. “I think it’s just about time,” he said. “We’ll suit up and go outside to see.”

In the dressing room they put on their space suits. As though they were his own children, Biff carefully checked the young Shannons’ air tanks, built-in heaters, and their helmet radios for talking to one another. Finally Biff rubbed gelatin on their helmets so that they would not frost over in the cold that was a hundred degrees below zero.

Outside they found space-suited figures gathered around the fuel rocket cannon. The cannon was pointed toward a shiny ball high up in the purple-black sky.

“Look, Sis, there’s the space ship toward which they’re going to shoot the fuel rocket,” Steve said.

“I see it!” Sue cried, her eyes dancing excitedly.

“They have to line up the cannon with the ship just right or the rocket won’t reach it,” Biff said.

“Won’t the rocket hit the ship?” Steve asked.

“No, it’ll lose all its speed by the time it reaches the ship,” Biff told him. “Then they’ll take on fuel from the rocket by means of a long hose.”

Suddenly the three of them heard a loud roar and saw a burst of flame. Like a bullet, the rocket left the muzzle of the giant gun and rose into the sky.

“They’ll be shooting off more rockets before they have enough fuel for the space ship,” Biff said. “There’ll be a little wait in between each firing.”

“Look, Biff, isn’t the space ship right over the canal where we’ll be heading back?” Steve asked.

“That’s right, Steve,” Biff answered. “You’ll remember, our ship is at the end of the canal. We’ll be able to see the rockets go off as we head back—which we’d better do right now, if we’re going to have any turkey and pumpkin pie!”

The canals of Mars had been carved out of a great desert by water and fierce winds. Because of the ice that filled them, they made good highways. The three went to the canal bank to see if their sled was ready to go, and it was. The sled looked like a big bombing plane with the wings off. Instead of wheels, there were long runners beneath it. In this sled Biff and his young helpers had brought supplies to the colony several hours before.

Steve, Sue and Biff climbed into the front seat. Then Biff shut the door. He pushed buttons in front of them. Steve and Sue felt the sled’s engines throbbing. The next moment the sled shot off over the smooth sheet of ice, Biff holding tightly to the steering wheel.

“Wheeeeee!” Sue screamed in delight. “Offffffffff weeeeeeee goooooooooo!”

“Like a rooooller cooooster!” Steve shouted.

They sped along at a hundred miles an hour. This was as much fun as they had had on their last space journey.

Each of their trips into space seemed to be more exciting than the last. They had won a lifetime free pass into space and by now they were sure they would need a lifetime in which to see all of its many wonders. A brave act by Steve on their first space trip had earned them their pass. Right now, Steve thought that their mother and home, back in Arkansas, seemed as far away as Deneb, the North Star of Mars.

“We’ll be there in about ten minutes,” Biff said. “The ship leaves in thirty, which gives us some spare time.”

“Look,” Sue said, “there comes the first fuel rocket back down in a parachute.”

“That’s right, Sue,” Biff replied.

Steve studied the bank of the canal. Along it he saw scrubby cactus, which was forever fighting for life in the cold, dry atmosphere. Beyond the bank stretched acres of red wasteland, and sand drifts piled up by strong winds that never stopped blowing.

A few minutes later, Sue noticed a bright streak against the purple sky. It was nearly as bright as the tiny sun, which was so far away that it could not keep Mars warm.

“There goes another fuel rocket!” Sue called out, pointing through the windshield.

As Biff caught sight of it, he jerked up sharply in his seat, bumping the shoulders of Sue and Steve on both sides of him.

“That rocket’s too low!” he exclaimed. “It’s not lifting! Something’s gone wrong!”

Steve felt chills run up his spine. He was seeing the danger too, now. The rocket was dropping ahead of them, a screaming bomb filled with explosive fuel. It was still quite a distance away, but even Steve knew that it would make a terrible blast when it struck the ice.

Biff’s feet hit the brakes of the sled and the runners chewed into the hard ice pack, shrieking, and bringing the sled to a skidding stop. The riders were slammed forward. Sue and Steve were dazed, but not hurt. When Steve’s mind cleared, he saw that Biff had thrown himself over in front of Sue and him to protect them. But in doing this, his helmet had thumped against the windshield. He was now slumped over and not moving.

“Sue!” Steve cried. “Biff is hurt!”

Just then they felt the shock of the explosion. It tilted the sled at an angle and dropped it down again with a hard jolt. The air was filled with flying chunks of ice. It looked like a hailstorm outside. The ice clattered against the windshield like stones. Sue and Steve were relieved when it finally stopped. But the explosion had left the ice sheet in front of them broken and choked with lumps of ice.

“Steve,” Sue moaned, “what are we going to do?”

Steve looked at Biff who was still not moving. He could see a big lump on Biff’s forehead where his head had struck the helmet, knocking him out. The children tried to revive their friend, but could not.

“We’ve got to get the sled to the ship ourselves, Sue!” her brother said. “Biff may need a doctor! Besides, I bet we’ve all missed our Thanksgiving dinner!”

“I won’t want any dinner if Biff is hurt badly!” Sue said tearfully.

At first it seemed like an impossible thing for a pair of twelve-year-olds to run the big sled. But Steve remembered how Biff had worked the controls and he believed he, too, could do it. He changed seats with the unconscious spaceman and tried the levers and buttons.

Presently the sled’s rockets began to pour fire out of the rear. But Steve couldn’t get the sled to move. He was afraid it had been damaged. Then Sue showed him a lever to push which she had remembered seeing Biff shove. As Steve worked it gently, the sled started off slowly.

“We’ll go slow,” Steve said, “and take it very easy.”

The explosion had hit at the far edge of the canal so that there was a narrow place on the other side where the ice was still smooth. Steve carefully guided the sled across the canal and through the unbroken part. When there was smooth ice before them, Steve picked up speed a little. As he drove, Sue tried to awaken Biff.

Steve would have found their adventure a lot of fun if things weren’t so serious at the moment. It wasn’t every day that a boy had the chance to drive a giant rocket sled on a distant planet!

At last Steve saw the round top of the space ship just over the horizon. It was at that moment that Sue called out the good news:

“Biff’s awakening, Steve!”

The boy saw their friend slowly rise up, then shake his head to clear it. When he smiled at them in his pleasant way, they were sure that he was going to be all right. By the time they had told him what had happened, he was his old self again. He took the controls and looked at his watch.

“Time’s running out,” he said. “We’ve got to hit top speed again. Hold onto your helmets! Here we go!”

And off they went at lightning speed once more. It seemed to Steve as if they covered the distance between them and the space ship in seconds.

As the sled came to a gentle stop beneath the giant freighter, Biff said, “It looks like we’ll make our Thanksgiving dinner on time after all, doesn’t it, kids?”

“Yeah,” Steve answered, “and this is certainly one Thanksgiving that I’m really thankful!”

“I know what you mean, Steve,” Sue said thoughtfully. “We’re thankful that we’re alive!”

Biff and Steve both nodded. It was a holiday none of them would ever forget.

_CARGO FOR CALLISTO_

The big rocket freighter was speeding through the star dust of outer space. It was carrying supplies to Callisto (one of the twelve moons of Jupiter) and the Shannons, on another space adventure.

Steve and Sue looked out a window of the freighter at the airless world growing in size. Callisto was a gigantic roughened rock, but it was a globe larger than the planet Mercury. It reminded Steve of a giant cockle-burr hanging in the sky.

Suddenly the children heard a tiny voice behind them say, “Rocket away!”

They turned and Sue exclaimed, “It’s Bud!”

The blue parakeet, a budgy, blinked lazily at them. The twins had met Mr. Whittle’s pet a week ago. He had taken a liking to them from the very start. They didn’t know that a few hours from now their very lives would depend on this little fellow.

“We’d better take him back to Mr. Whittle,” Steve said.

The budgy kept studying them with his flat face and blinking his tiny button eyes. Then he squawked again, “Rocket away!”

“It’ll be ‘rocket away’ for you, young fellow!” Steve said sternly. “Up on my finger, Bud!”

The bird did as he was ordered. They took him down the hall to Mr. Whittle’s room. Bud’s owner, off duty now, was a tall, spidery crewman with a big Adam’s apple. He always gave his pet full run of the ship.

Mr. Whittle whistled to the parakeet, but the bird stayed on Steve’s finger.

Mr. Whittle chuckled. “Hey, I believe he likes you two better than his master!”

“We like him, too,” Sue told the crewman.

“You can keep him for a few days if you want to,” Mr. Whittle said. “I’m going to be pretty busy after we land.”

“Gee, we’d like to look after him!” Steve answered.

“If you take him outside on Callisto, you’ll have to put him in that air-tight cage over there I had made. It’s sort of like a space suit for him.”

Sue and Steve played with Bud in the room they used for games until it was time to “strap down” for landing. Then they went to the couch hall and lay down on cots like the other space travelers were doing. They buckled straps across their bodies to keep them in place.

For a long time, Steve and Sue lay there as the big freighter began cutting its rushing speed. It felt to Steve as if a giant anvil were crushing downward on his chest. Take-off and landing were always the roughest moments in space travel, as the twins had already found out on other space trips.

At last the ship set down on Callisto. The young Shannons went back to the game room. Then with the bird on Steve’s shoulder, the twins looked out the window at the strange new world.

They saw a land bathed in ghostly twilight. Very little light was coming from the sun. It was so far away that it was only a small circle. Most of the light came from a huge shape that looked like somebody’s lost beach ball resting on the ground. Its bottom edge just touched the horizon.

Sue and Steve were joined by their father, who worked for the space freight company.

“That’s His Majesty, Jupiter—the king of planets,” Mr. Shannon told them. “He’s over a million miles away and yet he looks close enough to touch, doesn’t he?”

“Let’s go outdoors, Dad!” Steve begged.

“No reason why we can’t,” Mr. Shannon replied.

After they had put on their space clothes, Steve popped Bud into his warm, air-tight cage.

As they all went outside, they saw the crewmen unloading the cargo.

“There’s the colony over there,” Mr. Shannon said, pointing to a high framework that looked something like an oil derrick.

“They mine here for a mineral called magna. It’s very valuable, because without it we couldn’t have atomic engines. Magna is what keeps our rocket tubes from melting under the terrific heat that goes through them.”

“May we go down into the mines, Dad?” Steve asked.

“We’ll see if we can,” said his father.

As they walked toward the mining place, Mr. Shannon said, “Underneath us are pockets of poisonous gas like that found in Jupiter’s atmosphere. Sometimes it leaks into the mining tunnels causing danger from suffocation.”

“I sure hope the gas stays where it belongs while we’re down there!” Steve said and swallowed the lump of fear in his throat.

They turned their attention to Jupiter. It looked even more like a beach ball now with its stripes of beautiful colors. Mr. Shannon said the bands were floating ice bergs of the poisonous gases he was talking about.

“No ship can land on Jupiter,” he said. “Its gravity would crush a spaceman flat. Gravity pull is much stronger on the larger planets, you know. Jupiter’s atmosphere is many thousands of miles deep. Raging storms are going on beneath it all the time.”

“Ooo!” Sue gasped. “I guess we’re close enough to it then!”

Other wonders of the sky were the round beacons of Jupiter’s other moons, three of which were about the same size as Callisto. They hung like bright searchlights in the starry heavens.

The men at the mining place greeted the Shannons warmly. They had not seen anyone from Earth for so long that they had grown very lonely.

The chief mining engineer said he would be glad to take the visitors on an underground tour. His name was Dr. Harding. He was plump and short and wore black-rimmed glasses inside his space helmet.

He led them into an elevator and it sank into the darkness. Steve remembered about the poisonous gases that crept about underground and it made him shiver to think about it.

Dr. Harding watched Bud hopping around uncomfortably inside his small space cage. “Do you remember, Mr. Shannon,” he asked over his suit radio, “when they used to use canary birds in mines to warn about leaking gas? The birds would notice it first and give the miners time to get out.”

“I’ve read about that, Dr. Harding,” said Mr. Shannon.

“Now we have automatic warning machines in the tunnels to do that,” the chief engineer told Sue and Steve.

Deeper and deeper below the soil of Callisto the elevator sank. At last the cage reached the bottom, and the riders found themselves in a large cavern. There were machines and men all about, working busily. Tracks led off into tunnels and ore cars were running on them. Some were going empty into the tunnels while others were coming out full of rock and gravel.

“The magna is separated from the rock in that big machine over there,” Dr. Harding explained. “Want to ride an ore car into one of the tunnels?”

“Sure!” Steve spoke up.

“The mine is air-conditioned,” the chief engineer said, “so we can take off our helmets.”

This done, Steve let Bud out of his cage. The little bird hopped up on his gloved finger, saying, “Rocket away!” several times. His two-word language seemed to do for everything.

One worker controlled all the cars at a main switch in the middle of the cavern. The Shannons and their guide climbed into an empty ore car and it rolled into a tunnel.

Glistening dark rock crowded in on Sue and Steve from all sides. Steve hoped the walls were strong enough so they would not come crashing down on their heads! There were lights along the way to help brighten the gloom.

After clicking along like a trolley for awhile, the car came to the end of the line. It was a large room with more machines and workmen. The men were digging magna ore out of the wall with drills.

As Dr. Harding explained about the work, Bud began flitting about as though sight-seeing on his own. He was shy of the workers at first, but then made friends with them. He spoke to them with his favorite two words and the men laughed in great fun to hear him.

Then a few minutes later, Bud began acting queerly. He flew back to Steve’s finger and started wobbling as though dizzy.

“What’s the matter with him?” Steve asked.

“He’s sick or something!” Sue cried out. She took the budgy from Steve and cuddled him in her own gloves. But the little blue bird seemed to be no better.

Dr. Harding walked over to look at the bird. Then he ordered, “Everybody into the ore car! We have to get out of here fast! Sue, hold the bird up close to your suit!”

The workers dropped their tools as if they were red hot and climbed into the car. Mr. Shannon helped Sue and Steve on, then jumped on himself.

Dr. Harding pressed the electric button that was the signal to the operator in the main cavern to move the car. The car began to roll down the track. It picked up speed as Dr. Harding kept pressing the button.

“Leaking gas, Dr. Harding?” Mr. Shannon asked worriedly.

The chief engineer nodded. He sniffed the air like a hunting dog after a scent. “Take a deep breath, everyone, then hold it!”

Steve thought his lungs would burst, but finally Dr. Harding let them take another deep breath. By the time they had taken one more, the car had reached the main cavern. As it rolled to a stop, Dr. Harding jumped down and ran over to the car operator.

Steve saw a door slide down and close off the tunnel where they had come out. Then the little man gave a deep sigh and took off his black-rimmed glasses to wipe them.

Sue and Steve watched Bud hopefully. He was standing more steadily on Sue’s finger now.

“I think he’ll be all right,” the chief engineer said. “We sure owe Bud a lot for warning us the way he did. Something must have happened to the warning machine. It was supposed to set off a siren.”

“If it weren’t for Bud we might have been overcome before we could have gotten out of there!” Mr. Shannon added.

“You’re so right!” Dr. Harding said. “The men will go back in there in gas masks to find the leak and see what’s wrong with the warning machine.”

“We’re plenty lucky!” Steve sighed, his spine still prickly from their narrow escape.

Sue kissed the budgy. “You’re a hero, Bud,” she told him, “and we love you!”

Bud blinked lazily. Then as if to show that he was all right again, he squawked, “Rocket away!”

_THE BIG SHOW ON TITAN_

The space freighter had landed on Titan, the largest moon in all the Solar System. The Shannon twins had been anxious to reach this moon of Saturn because their father had told them that something very exciting might happen here before they left.

There was still another reason why the children had looked forward to the landing. They would meet a boy of their own age who was the son of a worker. He had been living on Titan for the past two years and would be able to show them around.

Steve and Sue came down the outside “gangway” of the cargo ship and stepped onto the frozen ground of the distant world. The twins wore space suits, of course, for the air outside was extremely cold and it was poisonous as well with raw methane and ammonia.

Steve saw beautiful Saturn, with its colored rings, filling much of the blue sky. Titan was a world of close mountains, worn smooth by lots of windy weather. A film of glistening ice covered the peaks like caps of glass.

“Look up there, Sue!” Steve said. “Over our heads! That’s the famous skyport of Titan!”

“I wish we could go up there!” Sue said.

“Maybe we’ll get the chance,” answered Steve.

Ahead of them stood a rounded plastic dome. Men were carrying into it cartons of supplies which the space freighter had brought. The twins’ father, who was an official of the American Space Supply Company, was still aboard to take care of the unloading.

A boy came out of the domed building. “Are you the Shannons?” he asked over his space radio.

“Yes, we are,” Steve replied.

“I’m Bobby King.”

Sue and Steve said they were glad to meet him. He asked if they would like to go up and see the skyport.

Both the young Shannons answered a quick, “Sure!” together.

They followed their new friend into the plastic dome. Bobby King pointed to an overhead cable. Hanging from the heavy cord was a cable car.

“All aboard!” Bobby called, like a train conductor.

Sue and Steve giggled with pleasure as they entered the car, followed by Bobby. Bobby pushed a switch and the cable car began to move.

“We’re going up like a corkscrew,” Bobby said.

Round and round, right out of the top of the building, moved the cable car. Up and up it went. It took about ten minutes to reach the top. As soon as they got out, two men passed them who were talking about a storm that was on the way.

“Boy, if there’s a storm coming, you two are sure in luck!” Bobby told Sue and Steve.

Steve and Sue looked at one another, puzzled. Why should their young friend be pleased over a coming storm?

They saw before them a space that looked as flat as a highway and larger than a football field. There was a row of hangars along the far side.

“Wow, we sure must be high!” Steve burst out. They seemed to be almost on a level with the mountains.

“We’re a whole mile off the ground,” Bobby told him. “The skyport rests on the corners of two mountain ridges.”

They went over to one of the clear plastic walls that edged the skyport.

“Gee, the freighter sure is little down there!” Sue said.

It almost took Steve’s breath away. The big space ship indeed looked no larger than a toy down below.

“Why did they go to such trouble to build this?” Steve asked.

“Because there wasn’t any place flat enough on the ground,” Bobby answered. “My father says they need a main skyport on Titan because there are so many companies here digging for uranium. The colonists fly here to get their supplies and mail.”

“I see some dark clouds over the mountains,” Sue said. “Does that mean a storm is coming?”

Bobby’s helmet nodded. “It sure does! You two are the luckiest ones! You got here right at the start of the storm season.”

Steve and Sue were still puzzled as to why Bobby wanted it to storm.

Bobby showed his guests a faint star burning through the blue atmosphere. “That’s Earth,” he told them, “750 million miles away. My father thinks we can go back for a visit in a few weeks. I’ll be glad.”

“Where do you live here, Bobby?” Sue asked.

“My father and I stay in an apartment a little way from here,” Bobby answered.

“How about school?” Steve wanted to know. “Do they have one on Titan?”

Bobby shook his head. “My father teaches me. He’s out with some prospectors today.”

Bobby showed them Titan’s other nine sister moons, which looked like glowing fireballs. Steve saw that most of the daylight came from Saturn because the sun was so far away. It wasn’t nearly as bright here as it was on Earth.

“I wish we could run over to Saturn for a visit,” Sue said, jokingly.

“You don’t really, Sue,” Bobby told her. “You couldn’t stand up in its heavy gravity. Saturn’s almost as big as Jupiter, you know.”

“What are Saturn’s rings made of?” Steve asked.

“Oodles and oodles of rocks,” Bobby replied. “They are traveling so fast that they make the rings look like one solid piece.”

Wind was beginning to howl around them and this seemed to make Bobby very excited.

The coming storm must be something special, Steve thought. His curiosity had been aroused strongly.

The clouds gathered darker and more thickly behind the mountains. The wind was driving harder.

“Hadn’t we better go inside?” Sue asked, worriedly.

“Shucks, no!” Bobby said. “It won’t be any fun unless we’re right out in it! There won’t be any rain. It’s too cold on Titan for rain.”

Suddenly the three heard a loud siren wail.

“That means a jet plane is coming in,” Bobby said. “All planes have to land when word of a storm gets around.”

The plane’s wheels touched down and the ship rolled along until a hook on it caught a line that stretched across the runway. The line brought the plane to a sharp halt.

The jet’s wings were folded down and the ship was pushed off to a hangar. Two more ships landed afterward. Then a blinding flash lighted up the sky. It made Steve and Sue blink and jump in fright.

“Look!” Bobby exclaimed. “The storm has begun!”

Other men had come out to see what was going to happen and they lined up along the edges of the skyport with the children.

Bobby pointed to a sparkling balloon of light that burst into a blossom of sparks over the mountains. A moment later a red dagger flash skipped across the peaks. During all this there were loud crashes and rumblings. Steve was scared and thrilled at the same time.

“It’s just like fireworks!” Sue called out.

Now Steve could understand why Bobby had looked forward to the storm. He guessed, too, that this was the exciting surprise their father had said might happen while they were here.

An orange pinwheel, like a Fourth of July sparkler, rose from a mountain top and looped upward. It grew bigger and bigger and fainter and fainter at the same time. It was really a beauty.

“What causes the fireworks?” Steve asked above the noise.

“Partly strong wind,” Bobby said loudly, “and partly Titan’s gases exploding against the mountain tops!”

They watched spellbound for fifteen minutes, then a half hour. The Shannons were sure they had never seen anything quite so breathtaking as this.

At one time a row of peaks seemed to glow with a sheet of red flame. The flame danced and flickered like a forest fire for a long time before it faded out.

The children had been enjoying themselves so thoroughly that they knew nothing of the peril that was heading their way.

The first warning came when one of the skyport men standing nearby shouted over his space suit radio. Steve whirled in alarm. His heart seemed to stop beating completely for a terrible moment.

A tardy plane had come in for a landing on the sky platform. But the howling wind had kept everyone from hearing the warning siren.

Because of the fierce blowing, the plane had not hooked firmly to the braking line. It scooted off to the side and was heading for the very spot where Bobby, Steve and Sue stood.

“Bobby!” Steve cried. “Get out of the way!” As Bobby ducked for safety, Steve also moved quickly. Sue screamed as Bobby grabbed her hastily by her space glove. He had to jerk her sharply in order to get her out of the path of the runaway plane.

The plane crashed into the plastic wall of the skyport, tearing out a section of wall as though it were thin cardboard. The ship was left dangling on the very edge as if ready to fall a mile to the ground.

“The poor pilot!” Sue cried. “Oh, I can’t look!”

But the skyport men had come running quickly over and together they pulled the jet plane back to safety. They helped the scared pilot out. He walked shakily off into one of the hangars.

“Whew! That was close!” Steve breathed. “For him and us, too!”

“My heart is still thumping like a drum!” Bobby said.

As for Sue, she was too upset to say anything at all.

They turned to look at the fireworks to take their minds off the accident. The wonderful ending of the show almost made them forget it completely.

They saw a dazzling white light burst like an empty volcano. The banner of fire rose as high into the sky as huge Saturn. Then it spilled over like a great fountain. It changed into purple, then blue, green and red.

Before dying out, it gave the big planet a lovely ruddy glow, showing up its rings like a gleaming necklace of rubies. That was the end of Nature’s grand performance.

“Wow, wasn’t that terrific?” Steve asked. “A show like that in a grandstand on Earth would cost you three-and-a-half.”

“Maybe four!” Sue chimed in.

“You can’t see this show anywhere on Earth, Steve,” Bobby said. “Titan is the only place. And the good thing about it is that it’s all for free!”

_ADVENTURE ON THE SUN’S DOORSTEP_

Sue and Steve Shannon watched the magic world of stardust through a port of the rocket freighter. The ship was moving under power of its atomic engines, headed toward the sun.

They had one more cargo stop to make before returning to their beloved soil on the Earth.

The twins heard the clack of magnetic soles behind them. Without such shoes holding them to the floor, space travelers would float about helplessly like wingless birds.

“Hi, kids,” greeted their father. “Growing tired of the view?”

“I guess I am, Dad,” Steve admitted. His blue eyes were tired.

“How far away is Apollo’s Chariot now?” Sue asked.

Mr. Shannon grinned. “That’s the umpteenth time you two have asked that. But I suppose I’m as restless as you are to get back to Mom in Arkansas.”

Hearing this made Steve suddenly homesick. There was really no place like home, just like the poet had said. Steve knew Sue felt the same way. He had seen a wistful look in her hazel eyes every time they had talked of Little Rock.

The seemingly endless days finally did end. The three Shannons went up into the lookout dome with the crewmen. The dome was covered by a darkened plastic screen to cut down the blinding glare of the sun, which was very close.

It was a heart-stopping sight for Sue and Steve. The planet Mercury covered the face of the sun like a black plate. Streaming out from the edges were mountainous tongues of living fire. Mr. Shannon called this flaming halo the sun’s _chromosphere_.

“Gee, what a thing to see!” Steve gasped.

“It’s—it’s unbelievable!” Sue added, breathless.

“Indeed, it is,” Mr. Shannon agreed. “See that thing like a lighted wheel just ahead of us? That’s Apollo’s Chariot. It was named after the famous Greek sun god, you know.”

Sue and Steve knew that Apollo’s Chariot was really a space laboratory that was a home for scientists who were studying the sun. They had been the ones who had given their tiny world its colorful nickname. It was protected with asbestos and other special material to shield it from the heat as it circled the great star, month after month, year after year.

“We had to contact Apollo’s Chariot while Mercury was shading our ship from the sun’s rays,” Mr. Shannon said. “We aren’t protected like Apollo’s Chariot is.”

“Mercury seems as big as the sun, the way it covers it completely,” Steve remarked.

“That’s because we’re so close to Mercury,” his father explained. “Actually, the sun is so much bigger it’s like comparing a pinpoint to a grapefruit!”

In the midnight darkness between the ships, giant searchlights had to be turned on. Then the scientists on the other ship came out onto their loading platform to receive their cargo. Conversation was carried on by means of space suit radios with those aboard the freighter, who stood on their own outside platform.

“Why can’t we get closer to Apollo’s Chariot?” Steve asked Biff Warren, who was the twins’ favorite among the crewmen. Biff was piling boxes and crates at the edge of the platform.

“Space regulations,” answered Biff. “If a meteor should hit one of us, the other ship would explode too if we were close. Also, rocket tubes are so tricky that you never know when one is going to misfire and send your ship scooting off suddenly in the wrong direction.”

One end of a double cable was fastened to rings on the freighter’s platform. Then the other end was tossed across the space between the two ships and attached by the scientists to their own side.

Steve saw the crewmen around him pick up cords from out of the cable equipment box. They fastened one end to buckles on their suits and the other to the cable. Steve guessed that the lines were a safety measure to keep the men from drifting off into space as they carried the cargo across.

The first crewman picked up a crate as lightly as if it were a pile of feathers. Then with his foot he shoved off from the platform.

He guided the crate through the emptiness with his gloved hands and the men on the opposite platform helped him aboard. Another crewman stepped off the freighter with another crate. Then another crewman with another piece of cargo. The carriers returned by the other cable line.

Steve went over to his dad who, as an official of the American Space Supply Company, was supervising the work as always. “Dad, may Sue and I carry a box across? We’ll be careful.”

Mr. Shannon thought a moment. “I suppose it will be all right. There’s no way you can go adrift if you fasten on to the cable. But you have to be careful you’re snapped on securely.”

Mr. Shannon made a place for them in line. Sue in front. There was a wait before Sue’s turn so that more crates could be placed on the platform’s edge. The children looked beyond Apollo’s Chariot at the huge black circle of Mercury as it masked the mighty sun.

“Biff,” Steve asked his friend as he was stacking the crates, “why couldn’t the Apollo scientists study the sun from Mercury?”

Biff chuckled and it made a funny crackling sound over the young Shannons’ radios. “Men will land on Mercury when they grow hides of asbestos, Steve. It’s so hot on the sunward side that there are supposed to be lakes and pools of lead there! The other side never sees the sun, so you can imagine how cold it is! Think you two would like to go there?”

“I should say not!” Sue answered for both of them.

When the next piece of cargo was ready to go over, Biff checked the children’s safety cords. Then he let Sue push off from the platform with a box in front of her. A few moments later, Steve followed. The boy heard his sister giggle excitedly as they floated across. Searchlight beams were in their eyes but they didn’t mind. Steve, too, thought this great fun after being cramped for so long on the freighter. He looked down at the empty space below, but he knew he could not fall and so was not afraid. Reaching the other platform, he and his sister were helped aboard.

“They sure are using young crewmen these days!” joked one of the scientists, a tall man who seemed to be working harder than the others. “Nice work, young folks!”

The scientist was in the act of changing the children’s cords over to the returning cable when a slight mishap occurred. One of the crates coming over bumped into him. He laughed as he again got to his feet but his laughter quickly changed to alarm when Sue suddenly pushed off from the platform. She had thought her cable line was secure and that she was ready to make the exciting trip back across the gulf.

“Wait, miss!” the scientist called. “I didn’t finish fastening your cable cord!” He reached for Sue but her suit slipped out of the fingers of his bulky space gloves.

Steve froze for an instant in terror at what he had seen. Then without thought of anything else except his sister’s danger, he dove right off the platform after Sue, not realizing or caring that his own cable cord was not fastened.

If the scientist had not grabbed for Sue she might have floated safely across to the freighter. But by touching her he had sent her off in a direction beneath it.

Over his radio, Steve heard her screaming for help and saw her flinging her arms and legs about like a drowning swimmer. Steve was moving faster than she and presently caught up with her.

“What are we going to do, Steve?” she cried, holding tightly to him. “We can’t stop! And it’s so dark out here!”

Steve knew that unless someone came to their aid they would drift on and on since there was no air to slow them down. But he didn’t tell Sue this.

He remembered, as he had at times before, that a spaceman must keep his head in an emergency. He spoke comforting words to Sue, telling her to try to be calm, that help would be coming.

Even as he told her this a spear of light hit them and a voice broke in on their radio: “Steve! Sue! Stop struggling! I’m on my way to you!”

“Biff!” Steve exclaimed, and the dread in his heart suddenly lifted. He looked over his shoulder and saw their big friend approaching, guided by the light that had been flashed on them from the freighter.

There was a little plume of flame trailing behind him. In a few minutes he had caught up with them. Sue was so glad to see him she grabbed the big spaceman and her helmet bumped against his in an attempted kiss.

“Oh, I’m so glad to see you, Biff!” she sobbed. “I was so _awfully_ scared!”

“You’re all right now,” Biff said gently. “Both of you hold on to me and we’ll go back.”

Steve took Biff’s left arm and Sue firmly grasped one of Steve’s. Biff carried a type of hand rocket, called a “pusher,” that he had used to shoot himself along toward them. By pointing the rocket in the opposite direction from which he wanted to go, the “pusher” pushed him in the manner of the rocket tubes on the freighter.

Biff pointed the pusher away from the freighter. Steve saw a burst of fire beside them and the three of them sped off toward the big ship. As Sue reached the platform, her father was there to help her aboard. She could see in his eyes the fear he had felt for them.

Steve was surprised to have the crew greet him warmly with pats on the back. The boy turned to his father. “Why are they calling me a hero?” he asked. “It was Biff who saved us!”

“Not taking credit away from Biff, any good spaceman would have done what he did,” said Mr. Shannon. “But few would have attempted your trick of jumping into space after your sister with no way of getting back. Right, Biff?”

Biff nodded his plastic helmet. “It wasn’t the smartest thing you could have done, Steve, but it showed your bravery. Courage counts just as much as ability in a spaceman. Don’t ever forget that, son.”

Steve, who wanted to be a spaceman some day, would not forget it.

_THE FLYING MOUNTAIN_

Steve and Sue were playing a game as the freighter headed through space toward Earth. It was fun trying to see who could build the higher tower of sticks. The young Shannons were in extra good spirits. Before long they would be seeing Mom and their home in Arkansas, after being in space for so many months.

Steve carefully placed the last stick on his tower which was almost as high as he could reach.

“_I_ won, Sis!” he exclaimed. But as he drew his hand away, it brushed against the tower, causing the sticks to drift off in all directions.

“_I_ won!” Sue cried gleefully, “Yours broke up!”

Steve made a face and began picking the sticks out of the air before they floated too far. It was lack of weight in space that made it possible to play such a game. The twins would have hung in the air like the sticks if their shoe soles were not held to the floor by magnetism.

“I’ll beat you next time,” Steve boasted.

Before they could start again, their father came into the room. “It looks as though we may not be getting home as quickly as we had expected, kids. Captain Furman has received an S. O. S. from a passenger rocket that’s down on the asteroid, Sierra.” The twins knew an asteroid to be one of the thousands of tiny planets in the Solar System.

“Are we going to her aid?” Steve asked.

“It depends on whether we have enough fuel or not,” his father replied. “Even atomic fuel runs out sometime, you know. Captain Furman is talking with his officers now. It’ll be a shame if we can’t help the _Pole Star_—as much as I want to see Mom.”

It was just like his unselfish dad to say that, Steve thought. He felt the same way about it. And he didn’t doubt that tender-hearted Sue was of the same mind.

Mr. Shannon started out of the room again. “I’m going to see what they are going to do.”

Steve and Sue went back to their game. But somehow it wasn’t as much fun now. People were in trouble and trouble in space was often a frightening thing.

It seemed like a long time before their father came back. He walked in so fast that his magnetic shoes sounded like tiny hammers. “Kids,” he said, “the captain wants to see you.”

“_Us?_” Steve asked.

“That’s right. Come quickly.”

They went out, leaving some sticks in mid-air and others drifting off. The young Shannons walked shyly into the captain’s room where all the officers stood. Steve felt out of place among the neatly uniformed spacemen.

Mr. Shannon was in charge of cargo which the freighter dropped off at different ports in space, for he was an official of the American Space Supply Company. But he had nothing to do with the running of the ship.

“Young folks,” said the tall captain, who had a blond mustache, “we want you to help us solve a problem.”

“Sir?” Steve asked, puzzled.

“Here it is,” went on the chief, in his booming voice. “If we go on past Earth to Sierra to help the _Pole Star_, it’ll leave us with only a fifty-fifty chance of having enough fuel to reach Earth. But the _Pole Star_ is running short of supplies and their radio just went dead a while ago. It’s too late to get help from Earth. The crew is divided on what we should do, so I decided to call you two in to see what you think.”

A husky crewman spoke out boldly, “What do these kids know about space, Captain? They’re not even old enough to be out here! I say stick to our course and get this crew and ship back safely to Earth!”

The remark angered Steve, but the spaceman looked too big to talk back to. Sue wasn’t so timid.

“You ought to be ashamed of yourself!” she exclaimed. “Thinking of yourself when other people are in trouble!”

Steve and his father were surprised at Sue’s outburst. Captain Furman and the other crewmen smiled.

“I think that solves our problem,” the captain spoke firmly. “If the young lady has courage enough to overlook the risk, the rest of us should have it, too. Thank you, Sue. We move at full rocket thrust to aid the _Pole Star_.”

As the Shannons went out into the corridor, Steve asked his sister, “Wow, Sue, what made you talk back to that big fellow like that?”

“He was so selfish!” Sue answered. “Besides, it made me mad to hear him say we didn’t know anything about space! Why, we’ve been over almost all of the Solar System, haven’t we, Dad?”