"We capture it," Rip said. "We blast it loose from its orbit and ride it back to earth."

He sat back and watched their reactions. At first they were stunned. Trudeau, the Frenchman, muttered to himself in French. Dominico, the Italian, held up his hands and exclaimed, "Santa Maria!"

Kemp, one of the American privates, asked, "How do we do it, sir?"

Rip grinned. "That's a good question. I don't know."

That stopped them. They stared at him. He added quickly, "Supplies came aboard at Marsport. We'll get the clue when we open them. Headquarters must have known the method when they assigned us and ordered the equipment."

Koa stood up. He was the only one who could have moved upright against the terrific deceleration. He walked to a rack at one side of the squadroom and took down a copy of "The Space Navigator." Then, resuming his seat, he looked questioningly at Rip. "Anything else, sir? I thought I'd read what there is about asteroids."

He could imagine the reaction when the machine turned up the name of a brand-new lieutenant. But the choice was logical enough. He knew that most, if not all, of the Planeteer astrophysicists were either in high or low space on special work. Chances are there was no astrophysicist nearer than Ganymede. So the choice had fallen to him.

He had a mental image of the Terra base scientists feeding data into the electronic brain, taking the results, and writing fast orders for the men and supplies needed. If his estimate was correct, work at the Planeteer base had been finished within an hour of the time word was received.

When they opened the cases brought aboard by the Martians, he would see that the method of blasting the asteroid into a course for earth was all figured out for him.

"... and he slugged into that asteroid going close to seven AU's," Santos was saying. The little Filipino corporal shrugged expressively.

Rip recognized the story. It was about a supply ship, a chemical drive rocket job that had blasted into an asteroid a few years before.

Private Dowst shrugged, too. "Too bad. High vack was waiting for him. Nothing you can do when Old Man Nothing wants you."

Rip listened, interested. This was the talk of old space hands. They had given the high vacuum of empty space a personality, calling it "high vack," or "Old Man Nothing." With understandable fatalism, they believed—or said they believed—that when high vacuum really wanted you, there was nothing you could do.

Other space talk grew out of space itself, and not history. For instance, the worst thing that could happen to a man was to have his helmet broken. Let the transparent globe be shattered and the results were both quick and final. Hence the oft-heard threat, "I'll bust your bubble."

Speaking of bubbles ... Rip realized suddenly that he and his men would have to live in bubbles and space suits while on the asteroid. None of the minor planets were big enough to have an atmosphere or much gravity.

If only he could get a look into those cases! But the ship was still decelerating and he would have to wait. He put his head against the chair rest and settled down to wait as patiently as he could.

Brennschluss was a long time coming. When the deceleration finally stopped, Rip didn't wait for gravity. He hauled himself out of the chair and the squadroom and went down the corridor hand over hand. He headed straight for where the supplies were stacked, his Planeteers close behind him.

Commander O'Brine arrived at the same time. "We're starting to scan for the asteroid," he greeted Rip. "May be some time before we find it."

"Where are we, sir?" Rip asked.

"Just above the asteroid belt near the outer edge. We're beyond the position where the asteroid was sighted, moving along what the Altair figured as its orbit. I'm not stretching space, Foster, when I tell you we're hunting for a needle in a junk pile. This part of space is filled with more objects than you would imagine, and they all register on the rad-screens."

"We'll find it," Rip said confidently.

O'Brine nodded. "Yes. But it probably will take some hunting. Meanwhile, let's get at those cases. The supply clerk is on his way."

The supply clerk arrived, issued tools to the Planeteers, then opened a plastic case attached to one of the boxes and produced lists. As the Planeteers opened and unpacked the crates, Rip and O'Brine inspected and the clerk checked the items off.

The first case produced a complete chemical cutting unit with an assortment of cutting tips and adapters. Rip looked around for the gas cylinders and saw none. "Something's wrong," he objected. "Where's the fuel supply for the torch?"

The supply clerk inspected the lists, shuffled papers, and found the answer.

"The following," he read, "are to be supplied from the Scorpius complement. One landing boat, large, model twenty-eight. Eight each, oxygen cutting unit gas bottles. Four each, chemical cutting unit fuel tanks."

"That's that," Rip said, relieved. Apparently he was supposed to do a lot of cutting on the asteroid, probably of the thorium itself. The hot flame of the torch could melt any known substance. The torch itself could melt in unskilled hands.

The next case yielded a set of astrogation instruments carefully cradled in a soft, rubbery plastic. Rip left them in the case and put them to one side. As he did so, Sergeant-major Koa let out a whistle of surprise.

"Lieutenant, look at this!"

Corporal Santos exclaimed, "Well stonker me for a stupid space squid! Do they expect us to find any people on this asteroid?"

The object was a portable rocket launcher designed to fire light attack rockets. It was a standard item of fighting equipment for Planeteers.

"I recognize the shape of those cases over there, now," Koa said. "Ten racks of rockets for the launcher, one rack to a case."

Rip scratched his head. He was as puzzled as Santos. Why supply fighting equipment for a crew on an asteroid that couldn't possibly have any living thing on it?

The Planeteers looked at each other. What were they up against, that such equipment was needed on a barren asteroid?

Private Dowst opened a box that contained a complete tool kit, the tools designed to be handled by men in space suits. Yards of wire, for several purposes, were wound on reels. Two hand-driven dynamos capable of developing great power were included.

Corporal Pederson found a small case which contained books, the latest astronomical data sheets, and a space computer and scratch board. These were obviously for Rip's personal use. He examined them. There were all the references he would need for computing orbit, speed, and just about anything else that might be required. He had to admire the thoroughness of whoever had written the order. The unknown Planeteer had assumed that the space cruiser would not have all the astrophysics references necessary and had included a copy of each.

"Maybe that's why the Federation sent Planeteers," Rip said, and was sorry the moment the words were out.

O'Brine's jaw muscles bulged, but he held his temper. "I'm going to pretend I didn't hear that, Foster. We have to get along until the asteroid is safely in an orbit around earth. After that, I'm going to take a great deal of pleasure in feeding you to the spacefish, piece by piece."

It was Rip's turn to get red. "I'm sorry, Commander. Accept my apologies." He certainly had a lot to learn about space etiquette. Apparently there was a time for spacemen and Planeteers to fight each other, and a time for them to cooperate like friends. He hoped he'd catch on after a while.

"I'm sure you'll be able to figure out what to do with this stuff," O'Brine said. "If you need help, let me know."

And Rip knew his apology was accepted.

The deputy commander arrived, drew O'Brine aside, and whispered in his ear. The commander let out an exclamation and started out of the room. At the door he turned. "Better come along, Foster."

Rip followed as the commander led the way to his own quarters. At the door, two space officers were waiting, their faces grave.

The senior space officer held out a sheet of flimsy. It was pale blue, the color used for highly confidential documents. "Sir, this came in Space Council special cipher."

"Read it aloud," O'Brine ordered.

"Yessir. It's addressed to you, this ship. From Planeteer Intelligence, Marsport. 'Consops cruiser departed general direction your area. Agents report crew Altair may have leaked data re asteroid. Take appropriate action.' It's signed 'Williams, SOS, Commanding.'"

Rip saw the meaning of the message instantly. The Consolidation of People's Governments of earth, traditional enemies and rivals of the Federation of Free Governments, needed radioactive minerals as badly, or worse, than the Federation. In space it was first come, first take. They had to find the asteroid quickly. It was to prevent Consops from knowing of the asteroid that security measures had been taken. They hadn't worked, because of loose space chatter at Marsport.

O'Brine issued quick orders. "Now, get this. We have to work fast. Accelerate fifty percent, same course. I want two men on each screen. If anything of the right size shows up, decelerate until we can get mass and albedo measurements. Snap to it."

Rip's eyes opened. Clear the missile ports? That meant getting the cruiser in fighting shape, ready for instant action. "You wouldn't fire on that Consops cruiser, would you, sir?"

O'Brine gave him a grim smile. "Certainly not, Foster. It's against orders to start anything with Consops cruisers. You know why. The situation is so tense that a fight between two space ships might plunge earth into war." His smile got even grimmer. "But you never know. The Consops ship might fire first. Or an accident might happen."

The commander leaned forward. "We'll find that asteroid for you, Mr. Planeteer. We'll put you on it and see you on your way. Then we'll ride space along with you, and if any Consops thieves try to take over and collect that thorium for themselves, they'll find Kevin O'Brine waiting. That's a promise, boy."

Rip felt a lot better. He sat back in his chair and regarded the commander with mixed respect and something else. Against his will, he was beginning to like the man. No doubt of it, the Scorpius was well named. And the sting in the scorpion's tail was O'Brine himself.

The Planeteers stopped talking as the voice horn sounded. "Get it! We are going into no-weight. Prepare to stay in no-weight indefinitely. Rotation stops in two minutes."

Rip realized why the order was given. The Scorpius could not maneuver while in a gravity spin and O'Brine wanted to be free to take action if necessary.

The voice horn came on again. "Now get it again. The ship may maneuver suddenly. Prepare for acceleration or deceleration without warning. One minute to no-weight."

Rip gave quick orders. "Get lines around the equipment and prepare to haul it. I'll get landing boats assigned and we can load. Then prepare space packs. Lay out suits and bubbles. We want to be ready the moment we get the word."

Lines were taken from a locker and secured to the equipment. As the Planeteers worked, the ship's spinning slowed and stopped. They were in no-weight. Rip grabbed for a hand cord that hung from the wall and hauled himself out into the engine control room. The deputy commander was at his post, waiting tensely for orders. Rip thrust against a bulkhead with one foot and floated to his side. "I need two landing boats, sir," he requested. "One stays on the asteroid with us."

"Take numbers five and six. I'll assign a pilot to bring number five back to the ship after you've landed."

"Thank you." Rip would have been surprised at the deputy's quick assent if Commander O'Brine hadn't shown him that the spacemen were ready to do anything possible to aid the Planeteers. He went back to the supply room and told Koa which boats were to be used, instructed him to get the supplies aboard, then made his way to Commander O'Brine's office.

O'Brine was not in. Rip searched and found him in the astro-plot room, watching a 'scope. Green streaks called "blips" marked the panel, each one indicating an asteroid.

"All too small," O'Brine said. "We've only seen two large ones, and they were too large."

"Space is certainly full of junk," Rip commented. "At least this corner of it is full."

A junior space officer overheard him. "This is nothing. We're on the edge of the asteroid belt. Closer to the middle, there's so much stuff a ship has to crawl through it."

"You didn't miss that one by much," Rip told the space officer.

"Don't have to miss by much," he retorted. "A few feet are as good as a mile in space. Our blast might kick them around a little, and maybe there's a little mutual mass attraction, but we don't worry about it."

He pointed to a blip that was just swimming into view, a sharp green point against the screen. "We do have to worry about that one." He selected a lever and pulled it toward him.

Rip felt sudden weight against his feet. The green point on the screen moved downward below center. The feeling of weight ceased. He knew what had happened, of course. Around the hull of the ship, set in evenly spaced lines, were a series of blast holes through which steam was fired. The steam was produced instantly by running water through the heat coils of the nuclear engine. By using groups or combinations of steam tubes, the control officer could move the ship in any direction or set it rolling, spin it end over end or whirl it in an eccentric pattern.

"How do you decide which tubes to use?" Rip asked.

"Depends on what's happening. If we were ducking missiles from an enemy, I'd get orders from the commander. But to duck asteroids, there's no problem. I go over them by firing the steam tubes along the bottom of the ship. That way, you feel the acceleration on your feet. If I fired the top tubes the ship would drop out from under those who were standing. They'd all end up on the ceiling."

Rip watched for a while longer, then wandered back to Commander O'Brine. He was getting anxious. At first, the task of capturing an asteroid and moving it back to earth had been rather unreal, like some of the problems he had worked out while training on the space platform. Now he was no longer calm about it. He had faith in the Terra base Planeteer specialists, but they couldn't figure everything out for him. Most of the problems of getting the asteroid back to earth would have to be solved by Lieutenant Richard Ingalls Peter Foster.

A junior space officer suddenly called, "Sir, I have a reading at two seventy degrees, twenty-three degrees eight minutes high."

Commander O'Brine jumped up so fast that the action shot him to the ceiling. He kicked down again and leaned over the officer's 'scope. Rip got there by pulling himself right across the top of the chart table.

"It's about the right size," O'Brine said. There was excitement in his voice. "Correct course. Let's take a look at it."

All hands gripped something with which to steady themselves as the cruiser spun swiftly onto the new course. The control officer called, "I have it centered, sir. We'll reach it in about an hour at this speed."

"Jack it up," O'Brine ordered. "Heave some neutrons into it. Double speed, then decelerate to reach it in thirty minutes."

The control officer issued orders to the engine control room. In a moment acceleration plucked at them. O'Brine motioned to Rip. "Come on, Foster. Let's see what Analysis makes of this rock."

Rip followed the commander to the deck below where the technical analysts were located. His heart was pounding a little faster than usual, and not from acceleration, either. He found himself wetting his lips frequently and thought, "Get hold of it, boy. You got nothing to worry about but high vacuum."

He didn't really believe it. There would be plenty to worry about. Like detonating nuclear bombs and trying to figure their blast reaction. Like figuring out the course that would take them closest to the sun without pulling them into it. Like a thousand things—all of them up to him.

"Anything yet?"

"No, sir. We'll have the albedo measurement in a few minutes. It will take longer to figure the mass."

The asteroid's efficiency in reflecting sunlight was its albedo. The efficiency depended on the material of which it was made. The albedo of pure metallic thorium was known. If the asteroid's albedo matched it, that would be one piece of evidence.

In the same way, the mass of thorium was known. The measurements of the asteroid were being taken. They would be compared with a chunk of thorium of the same size. If it worked out, that would be evidence enough.

Commander O'Brine motioned to chairs. "Might as well sit down while we're waiting, Foster." He took one of the chairs and looked closely at Rip. Suddenly he grinned. "I thought Planeteers never got nervous."

"Who's nervous?" Rip retorted, then answered his own question truthfully. "I am. You're right, sir. The closer we get, the more scared I get."

"That's a good sign," O'Brine replied. "It means you'll be careful. Got any real doubts about the job?"

O'Brine chuckled. "I never expected to get an admission like that from a Planeteer."

"And I," Rip retorted, "never expected to make one like that to a spaceman."

The chief analyst returned, a sheet of computations in his hand. "Report, sir. The albedo measurement is correct. Looks like this may be the one."

"How long before we get the measurements and comparisons?"

"Ten minutes, perhaps."

Rip spoke up. "Sir, there's some data I'll need."

"What, Lieutenant?" The chief analyst pulled a notebook from his pocket.

"I'll need all possible data on the asteroid's speed, orbit, and physical measurements. I have to figure a new orbit and what it will take to blast the mass into it."

"We'll get those. The orbit will not be exact, of course. We have only two reference points. But I think we'll come pretty close."

O'Brine nodded. "Do what you can, Chief. And when Foster gets down to doing his calculations, have your men run them through the electronic computer for him."

"Good idea. I think we'll dump you on the asteroid, Foster, and then blast off. Not too far, of course. Just enough to lead the Connie away from you if its screen picks us up."

That sounded good to Rip. "We'll be ready when you are, sir."

The chief analyst took less than the estimated ten minutes for his next set of figures. Commander O'Brine called personally while Rip was still searching for the right landing boat ports. The voice horn bellowed, "Get it! Lieutenant Foster. The mass measurements are correct. This is your asteroid. Estimated twelve minutes before we reach it. Your data will be ready by the time you get back here. Show an exhaust!"

Rip found Koa and the men and asked the sergeant-major for a report.

"We're ready, sir," Koa told him. "We can get out in three minutes. It will take us that long to get into space gear. Your stuff is laid out, sir."

"Get me the books and charts from the supplies," Rip directed. "Have Santos bring them to the chief analyst. I'm going back and figure our course. No use doing it the hard way on the asteroid when I can do it in a few minutes here with the ship's computer."

He turned and hurried back, hauling himself along by handholds. The ship had stopped acceleration and was at no-weight again. As he neared the analysis section it went into deceleration, but the pressure was not too bad. He made his way against it easily.

The chief analyst was waiting for him. "We have everything you need, Lieutenant, except the orbital stuff. We'll do the best we can on that and have a good estimate in a few minutes. Meanwhile, you can mark up your figures. Incidentally, what power are you going to use to move the asteroid?"

"Nuclear explosions," Rip said, and saw the chief's eyes pop. He added, "With conventional chemical fuel for corrections."

He felt rising excitement. The whole ship seemed to have come to life. There was excited tension in the computer room when he went in with the chief. Spacemen, all mathematicians, were waiting for him. As the chief led him to a table, they gathered around him.

Rip took command. "Here's what we're after. I need to plot an orbit that will get us out of the asteroid belt without any collisions, take us as close to the sun as possible without having it capture us, and land us in space about ten thousand miles from earth. From then on I'll throw the asteroid into a braking ellipse around the earth and I'll be able to make any small corrections necessary."

He spread out a solar system chart and marked in the positions of the planets as of that moment, using the daily almanac. Then he put down the position of the asteroid, taking it from the paper the chief analyst handed him.

"Will you make assignments, Chief?"

The chief shook his head. "Make them yourself, Lieutenant. We're at your service."

Rip felt a little ashamed of some of the unkind things he had said about spacemen. "Thank you." He pointed to a spaceman. "Will you calculate the inertia of the asteroid, please?" The spaceman hurried off.

"First thing to do is plot the orbit as though there were no other bodies in the system," Rip said. "Where's Santos?"

"Here, sir." The corporal had come in unnoticed with Rip's reference books.

Rip had plotted orbits before, but never one for actual use. His palms were wet as he laid it out, using prepared tables. When he had finished he pointed to a spaceman. "That's it. Will you translate it into analogue figures for the computer, please?" He assigned to others the task of figuring out the effect Mercury, the sun, and earth would have on the orbit, using an assumed speed for the asteroid.

To the chief analyst he gave the job of putting all the data together in proper form for feeding to the electronic brain.

It would have taken all spacemen present about ten days to complete the job by regular methods, but the electronic computer produced the answer in three minutes.

"Thanks a million, Chief," Rip said. "I'll be calling on you again before this is over." He tucked the sheets into his pocket.

"Any time, Lieutenant. We'll keep rechecking the figures as we go along. If there are any corrections, we'll send them to you. That will give you a check on your own figures."

"Don't worry," Rip assured him. "We'll have plenty of corrections."

Deceleration had been dropping steadily. It ceased altogether, leaving them weightless. O'Brine's voice came over the speaker. "Get it! Valve crews take stations at landing boats five and six. The Planeteers will depart in five minutes. Lieutenant Foster will report to central control if he cannot be ready in that time."

Santos grinned at Rip. "Here we go, Lieutenant."

Rip's heart would have dropped into his shoes if there had been any gravity. Only a little excitement showed on his face, though. He waved his thanks at the analysts and grinned back at Santos.

"Show an exhaust, Corporal. High vack is waiting!"

He checked all blast tubes to make sure they were clear. There were small single tubes on each side of the craft. A clogged one could explode and blow the boat up.

Koa, he knew, had checked everything, but the final responsibility was his. In space, no officer or sergeant took anyone's word for anything that might mean lives. Each checked every detail personally.

Rip looked around and saw the Planeteers watching him. There was approval on the faces behind the clear helmets, and he knew they were satisfied with his thoroughness.

At last, certain that everything was in good order, he said quietly, "Pilots, man your boats."

Dowst got into one and a spaceman into the other. Dowst's boat would stay with them on the asteroid. The spaceman would bring the other to the ship.

Commander O'Brine stepped through the valve into the boat lock. A spaceman handed him a hand communicator. He spoke into it. Rip couldn't have heard him through the helmet otherwise. "All set, Foster?"

"Ready, sir."

"Good. The long-range screen picked up a blip a few minutes ago. It's probably that Connie cruiser."

Rip swallowed. The Planeteers froze, waiting for the commander's next words.

"Our screens are a little better than theirs, so there's a slim chance they haven't picked us up yet. We'll drop you and get out of here. But don't worry. We have your orbit fixed and we'll find you when the screens are clear."

"Suppose they find us while you're gone?" Rip asked.

"It's a chance," O'Brine admitted. "You'll have to take spaceman's luck on that one. But we won't be far away. We'll duck behind Vesta or another of the big asteroids and hide so their screens won't pick up our motion. Every now and then we'll sneak out for a look, if the screen seems clear. If those high-vack vermin do find you, get on the landing boat radio and yell for help. We'll come blasting."

He waved a hand, thumb and forefinger held together in the ancient symbol for "everything right," then ordered, "Get flaming." He stepped through the valve.

"Clear the lock," Rip ordered. "Open outer valve when ready."

In front of the boxlike landing boats a great door slid open and air from the lock rushed out. Rip knew it was only imagination, but he felt for a moment as though the bitter cold of space, near absolute zero, had penetrated his suit. Beyond the lights from their belts he saw stars, and recognized the constellation for which the space cruiser was named. A superstitious spaceman would have taken that as a good sign. Rip admitted that it was nice to see.

"Float 'em," he ordered.

The Planeteers gripped handholds at the entrance with one hand and launching rails on the boats with the other and heaved. The boats slid into space. As the safety lines tightened, the Planeteers were pulled after the boat.

Rip left his feet with a little spring and shot through the door. Directly below him the asteroid gleamed darkly in the light of the tiny sun. His first reaction was, "Great Cosmos! What a little chunk of rock!" But that was because he was used to looking from the space platform at the great curve of Terra or at the big ball of the moon. Actually the asteroid was fair-sized when compared with most of its kind.

The Planeteers hauled themselves into the boats by their safety lines. Rip waited until all were in, then pulled himself along his own line to the black square o£ the door. Koa was waiting to give him a hand into the craft.

The Planeteers were standing, except for Dowst. Rip had never seen an old-type railroad or he might have likened the landing boat to a railroad box car. It was about the same size and shape, but it had huge "windows" on both sides and in front of the pilot—windows that were not enclosed. The space-suited men needed no protection.

"Blast," Rip ordered.

A pulse of fire spurted from the top of each boat, driving them bottom-first toward the asteroid.

"Land at will," Rip said.

The asteroid loomed large as he looked through an opening. It was rocky, but there were plenty of smooth places.

Dowst picked one. He was an expert pilot and Rip watched him with pleasure. The exhaust from the top lessened and fire spurted soundlessly from the bottom. Dowst balanced the opposite thrusts of the top and bottom blasts with the delicacy of a man threading a needle. In a few moments the boat was hovering a foot above the asteroid. Dowst cut the exhausts and Rip stepped out onto the tiny planet.

Rip watched, interested in how his men would tackle the problem. He didn't know the answer himself, because he had never driven a spike on an airless, almost gravityless world and no one had ever mentioned it to him.

Pederson searched the gray metal with his torch and found a slender spur of thorium perhaps two feet high a short distance from the boat. "Here's a hold," he said. "Come on, Frenchy. You, too, Bradshaw."

Trudeau, carrying the sledge, walked up to the spur of rock and stood with his heels against it. Pederson sat down on the ground with the spur between his legs. He stretched, hooking his heels around Trudeau's ankles, anchoring him. With his gloves he grabbed the seat of the Frenchman's space suit.

The rest was easy. The spike was used to anchor Trudeau while he drove another, at his longest reach. Then the second spike became his anchor, and so on, until enough spikes had been set to lace the boat down against any sudden shock.

The boat piloted by the spaceman was tied to the one that would remain and the Planeteers floated its supplies through a window. It took only a few moments, with Planeteers forming a chain from inside the boat to a spot a little distance away. Even the heaviest crates weighed almost nothing. They passed them from one to the other like balloons.

"All clear, sir," Koa called.

Rip stepped inside and made a quick inspection. The box was empty except for the spaceman pilot. He put a hand on the pilot's shoulder. "On your way, Rocky. Thanks."

"You're welcome, sir." The pilot added, "Watch out for high vack."

Rip and Koa stepped out and walked a little distance away. Santos and Pederson cast the landing boat adrift and shoved it away from the anchored boat. In a moment fire spurted from the bottom tube, spreading over the dull metal and licking at the feet of the Planeteers.

For a moment Rip had a wild impulse to yell for the ship to come back. He had been in vacuum before, but only as a cadet, with an officer in charge. Now, suddenly, he was the one responsible. The job was his. He stiffened. Planeteer officers didn't worry about things like that. He forced his mind to the job in hand.

The next step was to establish a base. The base would have to be on the dark side of the asteroid, once it was in its new orbit. That meant a temporary base now and a better one later, when they had blasted the little planet onto its new course. He estimated roughly the approximate positions where he would place his charges, using the sun and the star Canopus as visual guides.

"This will do for a temporary base," he announced. "Rig the boat compartment. While two of you are doing that, the rest break out the rocket launcher and rocket racks and assemble the cutting torch. Koa will make assignments."

While the sergeant-major translated Rip's general instructions into specific orders for each man, the young lieutenant walked to the edge of the sun belt. There was no atmosphere, so the edge was a sharp line between dark and light. There wasn't much light, either. They were too far from the sun for that. But as they neared the sun, the darkness would be their protection. They would get so close to Sol that the metal on the sun side would get soft as butter.

He bent close to the uneven surface. It was clean metal, not oxidized at all. The thorium had never been exposed to oxygen. Here and there, pyramids of metal thrust up from the asteroid, sometimes singly, sometimes in clusters. They were metal crystal formations. He guessed that once, long ages ago, the asteroid had been a part of something much bigger, perhaps a planet. One theory said the asteroids were formed when a planet exploded. This asteroid might have been a pocket of pure thorium in the planet.

There would be plenty to do in a short while, but meanwhile he enjoyed the sensation of being on a tiny world in space with only a handful of Planeteers for company. He smiled. "King Foster," he said to himself. "Monarch of a thorium space speck." It was a rather nice feeling, even though he laughed at himself for thinking it. Since he was in command of the detachment, he could in all truth say this was his own personal planet. It would be a good bit of space humor to spring on the folks back on Terra.

"Yep, I was boss of a whole world, once. Made myself king. Emperor of all the metal molecules and king of the thorium spurs. And my subjects obeyed my every command." He added, "Thanks to Planeteer discipline. The detachment commander is boss."

He reminded himself that he'd better stop gathering spacedust and start acting like a detachment commander. He walked back to the landing boat, stepping with care. With such low gravity a false step could send him high above the asteroid. Of course that would not be dangerous, since the space suits were equipped with six small compressed air bottles for emergency propulsion. But it would be embarrassing.

Inside the boat, Dowst and Nunez were setting up the compartment. Sections of the rear wall swung out and locked into place against airtight seals, forming a box at the rear end of the boat. Equipment sealed in the stern next to the rocket tube supplied light, heat, and air. It was a simple but necessary arrangement. Without it, the Planeteers could not have eaten.

The rocket launcher was already set up near the boat. It was a simple affair, with four adjustable legs bolted to ground spikes. The legs held a movable cradle in which the rocket racks were placed. High-geared hand controls enabled the gunner to swing the cradle at high speed in any direction except straight down. A simple, illuminated optical sight was all the gunner needed. Since there was no gravity and no atmosphere in space, the missiles flashed out in a straight line, continuing on into infinity if they missed their targets. Proximity fuses made this a remote possibility. If the rocket got anywhere near the target, the shell would explode.

Rip found his astrogation instruments set carefully to one side. He took the data sheets from his case and examined them. Now came the work of finding the exact spots in which to place his atomic charges. Since the computer aboard ship had done all the mathematics necessary, he needed only to take sights to determine the precise positions.

The sights were specially designed for use in space and his bubble was no obstacle in taking observations. He merely put the clear plastic against the curved sight and looked into it much as he would have looked through a telescope on earth.

As he did so, a hint of pale pink light caught the corner of his eye. He backed away from the instrument and turned his head quickly, looking at the colorimeter-type radiation detector at the side of his helmet. It was glowing.

An icy chill sent a shiver through him. Great, gorgeous galaxies! He had forgotten ... had Koa and the others? He turned so fast he lost balance and floated above the surface like a captive balloon. Santos, who had been standing near by to help if requested, hooked a toe on a ground spike, caught him, and set him upright on the ground again.

"Get me the radiation detection instruments," he ordered.

There was no immediate danger. It would take many days to build up a dose of gamma that could hurt them. But gamma was not the only radiation. They were in space, fully exposed to equally dangerous cosmic radiation.

The Planeteers had gathered while he read the instruments. Now they stood watching him. They knew the significance of what he had found.

"I ought to be busted to recruit," he told them. "I knew this asteroid was thorium, and that thorium is radioactive. If I had used my head, I would have added nuclite shielding to the list of supplies the Scorpius provided. We could have had enough of it to protect us while around our base, even if we couldn't be protected while working on the charges. That would at least have kept our dosage down enough for safety."

"No one else thought of it, either, sir," Koa reminded.

He looked at them grimly. "It won't kill us, and it won't even make us very sick. I'll have the ship take us off before we build up that much dosage."

Santos started. "But, sir! That means ..."

"I know what it means," Rip stated bitterly. "It means the ship has got to return in time to give us some nuclite shielding, or we'll be the laughingstock of the Special Order Squadrons—the detachment that started a job the spacemen had to finish!"