The Secret of the Ninth Planet

Burl's visit home was a curious interlude. Actually, he had been away only a few weeks, since the summer vacation had begun, yet this single day had an air about it different from that of any other homecoming. He found himself continually looking at things in a more inquisitive, more thoughtful manner.

That which had been commonplace was suddenly something valuable, a sight to be treasured. For he had realized, as he sat in the fast plane transporting him home, that the Earth was itself a planet among planets, and that this might possibly prove to be his last visit to the town where he had been born. He had pondered, as he had gazed out of the ship's windows, just what it could mean to depart from this world and travel among the uncharted reaches of empty and hostile space ... to set foot upon planets where no human foot had ever touched and to meet unguessable perils.

So his home, his mother, his friends, the street on which he lived, took on a novel air. He studied them while enjoying a quiet day at home. He watched the cars in the street, so amusingly compact and small, each designed in the fleeting style of the year. The cars of a dozen years ago had been designed for length and size, but the trend had been the opposite for a decade now. The cars grew smaller and their lines weirder as the manufacturers strove to compete.

What other planet could boast of such simultaneously astonishing ingenuity and wondrous tomfoolery?

He looked at the people going about their business, the other boys of his age intent on their summer jobs and summer fun, and wondered if he would ever be able to join them again without the cares of a world on his shoulders?

People were unaware of the crisis that hung over the solar system. There had been news of the dimming of the Sun, but the meaning behind it had been carefully screened, and the expedition was a top secret. It availed the world nothing to panic about this matter. Now the odd weather quirks had been forgotten, and the main subjects on people's tongues were the baseball scores and the latest telemovies.

When Burl kissed his mother and father good-by, it was with a sense that he was also kissing good-by to his youth, and entering upon a new period of the most desperate responsibility.

This mood lingered with him back at the base, although his companions of the trip to come seemingly did not share it. On the last day, quarters had been assigned in the Magellan, and the men moved their belongings to their tight bunks in the heart of the ship. Clyde had his way, and he and Burl shared a double-decker chamber.

There was a hustle and bustle in the valley. The supplies seemed unending, and Burl wondered why the variety. "For once, we've got lifting power to spare," was Russ's comment. "Nobody knows what we're going to need on the various planets, so Lockhart is simply piling aboard everything he can think of. You'd be amazed at the space we have for storage. And Caton says that the more we stick in there, the better the shielding is against the radiation belt surrounding Earth—and probably the other planets as well."

"I thought we were already well protected," said Burl. "With the atomic generators, we had to be shielded anyway. Haven't we lead lining all around our inner sphere quarters?"

Russell Clyde nodded. "Oh, sure, but the more the merrier."

He and Burl were already in their quarters, stowing their clothes. "We leave in an hour," said Burl. "Are we going to the launching base at Boothia, where the manned rockets go up?"

Clyde shook his head. "Lockhart talked it over with us yesterday, and we decided to take off from right here." By "us," Burl knew the operational group was meant, which consisted of the colonel, the two astronomers, Caton as head of the engineering section, and Haines, "To tell the truth, nobody knows how easily this ship will handle. We're shielded well enough so that a short passage through the radiation belt three hundred miles up and for the next fifteen hundred miles shouldn't have any effect on us at all. The rockets, which can't be shielded because of the weight limitations, have to go up at Boothia because there, at the North Magnetic Pole, there's a hole in the radiation."

Boothia Peninsula was a barren spot far up in the Arctic Zone on Canada's frozen eastern coast. On it was constructed the world's major space port—a lonely outpost from which rockets departed for the equally lonely Moon bases. Burl had read about it and had looked forward to seeing it, but realized that the flight of the Magellan marked still another change in the fast-altering history of the conquest of space.

The hour passed quickly. The little valley was cleared of visitors. The crew was called to take-off posts—Lockhart at the controls, Clyde and Oberfield at the charts, Detmar watching the energy output. The rest of the crew had been strapped into their bunks. By special request, Burl was observing in the control room, seated in a half-reclining position like the others, in a well-padded chair, strapped tight.

Haines had remarked as he had supervised the strapping-in, "Nobody knows whether this is going to be necessary. But we're taking no chances." He'd gone to his quarters and done the same thing.

Lockhart watched the registering of the dials in front of him, waiting for the load to build up. There was a muffled whine from overhead as the generators built up current. Detmar called out a cryptic number every few seconds and the colonel checked it. The two astronomers were idle, watching their viewers. They'd made their calculations long before.

"Time," called out the colonel, pressing a button. A gong rang throughout the quarters. He moved a lever slowly.

Burl waited for the surge of pressure he had read always occurred at take-off. But there was no such pressure. He lay back in his seat, gripping the arms. Gradually he became aware of a curious sensation. He seemed to be getting lightheaded, and to tingle with unexpected energy. He felt an impulse to giggle, and he kicked up his foot to find it surprisingly agile. About him the others were stirring in their seats as if caught by the same impulses.

Now he felt loose against his bonds and he became a little dizzy. There was a pounding in his head as blood surged within him. His heart began to beat heavily.

"We're losing weight," muttered Clyde from his chair, and Burl knew the ship was tensing to take off.

The great generators were beginning to push against Earth's gravity and, as their force moved upward to match Earth's, the weight of everything in their sway decreased accordingly. Lockhart's first move was simply that—to reduce the pull of Earth to zero.

In a few moments that point was accomplished. A state of weightlessness was obtained within the Magellan. Those watching outside from bunkers in the surrounding mountains saw the huge teardrop shiver and begin to rise slowly above its cradle of girders. It floated gently upward, moving slowly off as the force of Earth's centrifugal drive began to manifest itself against the metal bubble's great mass.

Everyone on the crew had experienced zero gravity, either in the same tests Burl had undergone or on actual satellite flights, and thus far, no one was too uncomfortable. The entire structure of the ship quivered, and Burl realized that the inner sphere which housed their air space was hanging free on its gymbals.

Lockhart rang a second gong, then turned a new control. The pitch of the generators, faintly audible to them, changed, took on a new keening. The ship seemed suddenly to jump as if something had grasped it. The feeling of weightlessness vanished momentarily, then there was a moment of dizziness and a sudden sensation of being upside down.

For a shocking instant, Burl felt himself hanging head downward from a floor which had surprisingly turned into a ceiling. He opened his mouth to shout, for he thought he was about to plunge onto the hard metal of the ceiling which now hung below him so precipitously.

Then there was a whirling sensation, a sideways twisting that swung him about against the straps. As it came, the room seemed to shift. The curved base of the control room, which had been so suddenly a floor, became in a moment a wall, lopsided and eerie. Then it shifted again, and, startlingly, Burl sagged back into his cushioned seat as the hemispherical room again resumed its normal aspect.

Lockhart bent over the controls, cautiously moving a lever bit by bit. Clyde was bent over his viewer, calling out slight corrections.

Now, at last, Burl felt the pressure he had expected. His weight grew steadily greater, back to normal, then increased. He found himself concentrating on his breathing, forcing his lungs up against the increasing weight of his ribs.

"Hold up," his buzzing eardrums heard someone say—possibly Oberfield. "We don't need to accelerate more than one g. Take it easy."

The weight lessened instantly. Then the pressure was off. Everything seemed normal. Lockhart sat back and began to unloosen his straps. The others followed suit.

In one viewer, Burl glimpsed the black of outer space, and in another, the wide grayish-green bowl of the Earth spreading out below. In a third he saw the blazing disc of the Sun.

"Did everything go all right?" he asked quietly of Clyde.

The redhead looked up at him and smiled. "Better than we might have expected for a first flight," he said.

"We're latching on to the Sun's grip now. We're falling toward the Sun; not just falling, but pulling ourselves faster toward it, so that we can keep up a normal gravity pressure. We're soon going to be going faster than any rocket has ever gone. The living-space sphere rotated itself as soon as we started that. That's what made everything seem upside down that time and why everything has come back to normal."

Burl nodded. "But that means that in relation to Earth we are ourselves upside down right now!"

"Of course," said Clyde. "But in space, everything is strictly relative. We are no longer on Earth. We are a separate body in space, falling through space toward the Sun."

"Why the Sun?" asked Burl. "I thought our first objective was to be the planet Venus?"

"It was too hard to get a fix on Venus from so near the Earth. Instead, we latched on to the Sun to pull us inward. When we are near to Venus' orbit, we'll reverse and pull in on Venus," was the astronomer's answer.

"Isn't that rather risky?" asked Burl, remembering some of the quick briefings he had been given. "That's a departure from your plans."

Lockhart looked up quickly. "Yes, you're right," he admitted. "But on a trip like this we've got to learn to improvise and do it fast. We made that decision at take-off."

For an instant Burl felt a chill. He realized then what all the other men on the ship had known all along—that in this flight they were all amateurs, that everything they did was to be improvisation in one way or another, that they must always run the risk of a terrible mistake.

Had latching on to the Sun been the first such error?

Gradually the ship settled down to routine. There was, as Burl discovered, nothing very much to do for most of the crew on such a space flight. The course was charted in advance, a pattern laid out that would carry the ship falling toward its objective—falling in a narrow curving orbit. A certain amount of time would pass during which the ship would traverse a specific section of this plotted route at a certain rate of speed or acceleration.

Then, at a specified moment, the speed would be checked, the attraction of the Sun reversed, and the ship would attempt to brake itself and to halt its fall toward the great Sun. At such a time as its fall came to a stop, it should, if the calculations had been correct, be crossing the orbit of the planet Venus in the same place and at about the same moment that Venus itself would be. In that way, the ship would arrive at the planet.

Now all these calculations had been made, and once made, set into motion on the control panels of the ship. The interval of many days between actually left little to do, except for making astronomical observations, checking on the performance of the stellarators, setting a watch against the damage caused by meteors and micro-meteors, and following the ordinary procedures of meals and sleep periods. The men set up an Earth-time schedule of twenty-four hours, divided the crew into three eight-hour shifts, and conducted themselves accordingly.

Burl did not find time weighing on his hands. Despite the limited space available to the ten men, there was always something to learn, and something to think about.

When Russell Clyde was off duty, he spent much time with Burl at the wide-screen viewers that showed the black depths of interplanetary space surrounding them. The Earth dwindled to a brilliant green disc, while ahead of them the narrow crescent of approaching Venus could be seen growing gradually. Ruddy Mars was sharp but tiny, a point of russet beyond the green of Earth. And the stars—never had Burl seen so many stars—a firmament ablaze with brilliant little points of light—the millions of suns of the galaxy and the galaxies beyond ours.

On the other side, the side toward which they fell, the Sun was a blinding sphere of white light, its huge coronal flames wavering fearfully around its orb.

Seen to one side, surprisingly close to the Sun, was a tiny half-moon. "That's Mercury," said Russ, pointing it out. "The smallest planet and the closest to the Sun. After we leave Venus, we'll have to visit it. We know there's a Sun-tap station there—and because it's so close to the Sun—its orbit ranges between twenty-eight million miles and under forty-four million miles—the station must be a most important and large one."

Burl gazed at the point of light that was the innermost planet. "Those Sun-tap stations ... The more I think about it, the more I wonder what we're up against. It seems to me that it ought to be easy for the kind of people who can build such things to catch us and stop us. In fact, I wonder why they haven't already gone after us for stopping the one on Earth?"

Russ whistled softly between his teeth. "We've some ideas about that. The military boys worked on it. You know you can figure out a lot of things from just a few bits of evidence. We have such evidence from what happened to you on Earth. You ought to speak to Haines about it."

Burl turned away from the viewer. "Let's find him now. I don't think he's very busy. He said something about catching up on his reading this period."

Russ nodded, and the two of them got up from their seat. With a wave to Oberfield and Caton on duty at the controls, the two climbed down the ladder that led into the middle part of the living space. They looked into Haines's quarters but he wasn't there. So they went down the next hatchway into the lower section.

Haines and Ferrati were sitting at a table in the cooking quarters, drinking coffee. The two men, both heavy and muscular, used to the open spaces and the feel of the winds, were taking the enforced confinement in the cramped and artificially oxygenated space of the ship with ill ease. For them, it was like a stretch in jail.

They greeted the two younger men jovially and invited them to a seat. While Russ poured a cup of coffee for himself, Burl opened the subject of how much the expedition had worked out about the enemy.

Haines's pale blue eyes gleamed. "You can know an awful lot about an enemy if you know what he didn't do as well as what he did do. If you figure out what you yourself should have done under the same circumstances, and know he didn't do, why, that gives you some valuable hints as to his deficiencies. As we see it, we've got a fighting chance of spoiling his game. Certainly of spoiling it long enough to allow Earth several more years to get a fleet of ships like this into operation and give him plenty of trouble."

Suddenly Burl felt more cheerful. At the back of his mind there had been a carefully concealed point of cold terror—he remembered the clean efficiency of the Sun-tap station, the evidence of a science far beyond that of Earth. He pressed the point. "Just what do we really know?"

Haines leaned back and rubbed his hands together. "There were several things that gave their weaknesses away. When we put it all together, we decided that the enemy represents some sort of limited advanced force or scouting group of a civilization still too far away to count in the immediate future. We decided that the enemy isn't too aware of our present abilities—that his intelligence service is poor as far as modern Earth is concerned. We figure he won't be able to act with any speed to repair the damages we make."

"Tell them how we worked that out," said Ferrati, who had begun to grow again the short black beard that Burl remembered he had worn on his famous expeditions.

"Well," said Haines, drawing the word out to build up suspense, "did you know that the station in the Andes, the one you cracked open, was built at least thirty years ago? And never put into operation in all that time?"

Burl was surprised. "Why ... I hadn't thought of it—but it could have been. That valley was so isolated and deserted, probably nobody would ever have spotted it.

"Right," Haines added, "and our investigation team studied the remains, the foundations, the layout, and we're sure it's been there at least three decades. That's one clue.

"The second clue was the relative flimsiness of the walls. The builders hadn't expected us to be able to blow them up. They were some sort of quick construction—a plastic, strong, but not able to hold up against blasting powder, let alone real heavy bombs or A-bombs.

"Now why was that? And the third clue, why didn't they have a repair system available, or at least some sort of automatic antiaircraft defense?"

Burl looked at Ferrati. The latter was watching him shrewdly to see if he could figure it out.

"The builders didn't expect an air attack," said Burl slowly, "because of the air disturbances. They did not know we would have a Moon base that could spot their location. Hence they figured that our civilization would remain as it was thirty years ago. We wouldn't have been able to spot the location at that time, because it required outer-space observation. It might have taken us several years of tramping around to locate it."

"And the lack of a strong permanent construction? After all, a concrete and steel-enforced embankment, which any military force on Earth could have put there, would have balked your dynamite attack," probed Haines.

"That means they didn't have the time or the means to make such a construction. They must have had a single ship with the kind of equipment that could lay out a quick base in the shortest time!" said Burl.

"Right!" snapped Haines. "The Sun-tap must have been built by a relatively small team, which probably came in a single explorer ship. The ship was equipped with automatic factory machinery that could turn out an adequate base for an uninhabited planet, an airless moon, and so on—but they didn't have the stuff for a fortified base—and they didn't have the manpower to build it."

"Another indication of that is the thirty-year delay," added Ferrati. "Obviously, they arrived in this solar system from somewhere outside it. We figure that way because otherwise they would have been prepared to do the job on all the planets in the same trip and start operations at once. They must have made some observations of this solar system from a point in space at least as far away as another star. That means not less than four and a half light-years away—Proxima Centauri being the nearest star after our Sun, and four and a half light-years from us. Their observations were imperfect. They found more planets and problems than they had supposed. So they had to make a second trip to get enough supplies to finish their Sun-tap base constructions. It took them thirty years between the first stations and the ones that completed the job.

"And that, too, suggests that only one ship was originally involved here. Of course, maybe they came back with more the second time, but it still looks as if the main force hasn't arrived. And won't, until after the Sun novas."

"Then that means," said Burl quickly, "that we are still dealing with just a small and isolated group?"

"Maybe," said Haines. "Just what constitutes a small group may be hard to say. I rather think they'd have brought the engineers and at least an advance working party of settlers with them the second trip in. But they are still short of available ships—they're still not aware of what we may be going to do."

"Why is that?" asked Burl.

Haines looked thoughtful. "This is conjecture. But if they planted any spies among our Earth people, there's been no contact, because otherwise they'd have known we could track and crack their base as soon as it started. This means that they still haven't had scouting ships to spare for checking up on what they did the first time. No checkup means no spare personnel to do the checking. They just assumed that we hadn't caught on, and started operations by remote control as they had originally planned."

"And that also may mean that these people are hard up," said Ferrati. "Wherever they came from, their civilization has been great, but it's gone to seed. They plan to seize another solar system, start over again, and they haven't the manpower to do an adequate job—and they haven't the abundance of material needed to set up simple check and guard stations, such as any major Earth nation would have the sense to do."

"Why, that means we've got a fighting chance to lick 'em," said Burl joyfully. "I kept thinking we'd run into more than we could cope with."

"We've got a fighting chance, all right," said Haines. "We may be able to rip up their Sun-tap layouts, but what if we meet the main explorer ship itself? Anybody who can cross interstellar space and warp the power of the Sun, can probably outshoot, outrun, and outfight us. Let's hope we don't meet them until we've done our work."

On this note the little discussion broke up as the gong rang for the next watch.

It made sense to Burl. If the Magellan could just operate fast enough, keep on the jump, they'd save the day. But—and he realized that nobody had mentioned it aloud—it also followed that the enemy—however small its group—was still in the solar system somewhere and would certainly be starting to take action very soon now.

The time came when the ship was to start slowing, to prepare itself for the meeting with Venus. Burl saw the hour and minute approach and watched Lockhart take the controls and set the new readings. The steady hum of the generators—a vibration that had become a constant feature of the ship—altered, and for everyone it was a relief. Their minds had become attuned to the steady pitch. One didn't realize how annoying a nuisance it was until it stopped. As the stellar generators let down on the drag on the Sun, the gravity within the ship lessened. In a few moments there was a condition of zero, and those who had forgotten to strap themselves down found that they were floating about in the air, most of them giddy.

There was a shift in the pitch, and the generators applied repulsion against the pull of the Sun. Those floating in the air crashed suddenly against the ceiling, then slid violently down the walls onto the floor as the inner sphere rotated on its gymbals to meet the new center of gravitational pull—this time away from the Sun.

The viewers flickered off and then on again as their connecting surfaces inside and outside the sphere's double layer of walls slid apart and matched up again. For an instant, as he saw the viewers blank out, Burl thought of what might happen if the sphere didn't rotate all the way. They would find themselves blind.

Now the ship proceeded on its charted orbit, slowing to meet Venus. Several hours went by, one meal, and Burl had returned to his bunk, his rest period having arrived. Russ remained at the controls on duty, checking astronomically the new speed and deceleration.

Burl tossed restlessly, the light out in the little cabin. Something was bothering him, and after a while he realized that Clyde should have come off duty before this. He glanced at the clock and calculated that Russ was two hours overdue. What was wrong?

He slipped out of his bunk and climbed into his pants. Ascending into the control room, he saw Lockhart, the two astronomers, and the entire engineering crew gathered over the controls in worried concentration.

He peered over their shoulders, but the dials meant little to him, since he did not know what they should have said. "What's happened?" he asked Russ.

Russ took him aside. "We're not going to make our connection with Venus," he said. "Our generators didn't operate exactly as we had hoped. We haven't been able to slow down enough, the pull of the Sun is stronger than the power we can raise to stop it at our present speed. We're going to shoot past Venus' orbit way ahead of the planet, and we're still heading sunward at a faster rate than we figured on."

"You mean—we're falling into the Sun!" gasped Burl.

"As things stand right now," said the youthful astrogator, "that's just what is happening."

It seemed strange to Burl at that moment that there wasn't more excitement on board the Magellan. To learn so early in the game that all were doomed should have brought more reaction. It should have excited some sort of frenzy, or efforts to abandon ship, or something. But the men in the cabin, though keyed up, were anything but panicky.

Instead, there seemed to be grim concentration on their faces, an earnestness that spoke of a plan. Through a viewer which had been shielded so that the light would not blind the eyes, Burl could see the wide disc of the Sun now. A few spots were visible on its blazing surface, and great tongues of burning gases encircled it for hundreds of thousands of miles. Were they really destined to end a mere cinder—an instantaneous flicker of fire in one of those prominences?

Clyde was working with Oberfield at the calculators. Burl watched them in silence, trying to determine what it was they were getting at. Finally they pulled a figure from one of their machines and took it over to Lockhart and the engineers. There was a brief conference, and something seemed to be agreed upon.

Clyde's face, which had been tense, was now more relaxed. "I think we've got the problem licked," came the good word.

"What's up?" asked Burl. "If we shoot past Venus, we should still be able to come to a stop, fall away from the Sun and maybe catch up with Venus again. It would take longer, but...."

"We're altering our plans," interrupted Russ. "Of course, we could brake—that much we found out for sure. The trouble lay in our lack of effective tests for the Magellan's drive. We thought we knew just what it would do, but after all, the problems of space are intricate. It turned out that it did not act so effectively against the Sun as had been calculated. Either that, or the Sun's pull was stronger at this proximity than registered on our instruments. Chasing after Venus, after coming back to its orbit, could be done, but it would prove time-consuming and difficult to plan. What we are doing instead is altering our schedule."

"But then there's no other place to go from here but Mercury. Is that what the new plan is?" Burl asked him.

Russ nodded. "Mercury is coming around this side of the Sun. By the time we have braked, we will be closer to its orbit than to that of Venus. So we shall proceed inward toward it and make our first planetfall there."

Mercury, the smallest and hottest planet in the system. Burl remembered that it was one of the two worlds that they knew for sure had a Sun-tap station on it. He went down the hatch to carry the news to the landing crew.

Haines, Burl discovered, had already heard the new plan on the intercom from Lockhart. As soon as Burl joined them, the four men, including Ferrati and Boulton, went into a planning session.

The problem of Mercury was a hard one. As Ferrati remarked, "It would have been better to tackle this one last instead of taking it on first."

"Yes, but on the other hand," was Haines's comment, "Mercury's station is probably one of the most important—located as it is, so close to the Sun. With ideal conditions for steady, undiverted concentration of solar power, it must be the primary station in the system."

"The problem boils down—and I do mean 'boils'—to heat," Boulton laughed. "Mercury rotates on its axis only once a year—its year being only eighty-eight of our days long. This means that just as the Moon presents only one side to the Earth, Mercury always presents the same hemisphere to the Sun. On the Sun side, therefore, there is always day. The Sun appears to be fixed in the sky. Naturally, we assume the Sun-tap station will be on that sunny side. And the heat must be terrific."

"Matter of fact," said Haines dryly, "the records show the heat in the center of the Sun side reaches 770° Fahrenheit. Enough to keep tin and lead molten."

"The problem is how to reach the station over such a boiling landscape," summed up Burl. "It seems to me that the absence of an atmosphere could answer part of the problem."

Haines nodded. "Let's get to work on a plan of action, men. We've got a few days to get our equipment laid out."

Those few days passed quickly enough. When several possible schemes had been outlined, the men made lists of the types of equipment that might be used with each. Then, putting on pressurized space suits and carrying air tanks, they left the inner sphere and worked through the cargo space surrounding it within the outer frame of the spaceship. There had originally been air here, but now they found most of it was gone, thinned out from infinitely tiny leaks in the outer shell caused by the constant bombardment of microscopic bits of meteoric dust.

They located each piece of equipment and moved it into position for easy handling.

The ship came to its halting point, where the repulsion against the Sun finally braked it against the gravitational pull of the Sun. Then, by increasing the selective pull of the approaching planet Mercury, they moved off in that direction.

Mercury was changing in appearance. As they neared it from the outer side, its lighted half swung away from their view, and what they saw was a constantly narrowing crescent, growing larger even as it narrowed. Finally the hour came when they swung up close, coming in on the eternally sunless, night side of the little planet.

They swooped low over the dark surface, taking observations and measurements. "It's not as cold as we might suppose," said Oberfield after his first readings. "There's a certain amount of heat all along the rim of the dark side. Radiation, I suppose, as well as the fact that there's a certain amount of wobbling done by the planet."

Burl was studying the surface. "Seems to me that much of the dark side has a gleam to it. Something reflects the stars; I see little glints of light, shifting and blinking."

"I can guess what that is," said Russ. "It must be covered, at least in the central portions, with a sea of frozen gases. What atmosphere Mercury had long ago must have congealed there."

The ship moved along toward the twilight edge, then began circling the planet along that intermediate belt, where the Sun could be seen peeking over the horizon in eternal dawn. There was a cluster of men at the radiation counter, looking for evidence of the Sun-tap station. Finally, after passing over a chain of darkened mountains, eerily lighted at the peaks by the Sun, there came a yell. Distortion had been detected.

Once on it, they swung the ship outward into space again and moved along further over the sunlit side. Burl stared into the telescopic viewers as they probed the surface.

He saw an ugly and terrifying world. The planet, which had a diameter of only 3,100 miles, compared to Earth's 7,900, was virtually without an atmosphere. Its surface was baked hard, brilliantly white, covered with long, deep cracks that cut hundreds of miles into the shriveled and burned surface. There were areas of dark mountain ranges, bare and jagged, whose metallic surfaces imparted a darker shade to the pervading glare. And there were patches here and there on the surface that gleamed balefully—probably spots of molten material.

Haines, standing next to him, was muttering, "It can't be too far in, it can't. How could they build it?"

Then Burl found what they were looking for.

A huge canyon tore raggedly across a plain. There was a jumble of mountains, a chain edging in from the twilight zone. And in a corner, about two hundred miles out into the hot side, at a narrow ledge where the mountains came down and the canyon came together, there was a circular structure.

They could see, as soon as the telescopic sight had been adjusted, that it was a large station. It was encircled by a featureless wall. It had no roof. Rising on masts above it was a whole forest of gleaming discs pointing at the Sun low in the sky.

On the tops of the mountain peaks, a half mile from the station, was another series of masts. These were aimed away from the Sun into the dark airless sky and toward the other planets.

"The accumulators and the transmitters," said Burl. "We'll have to get them both."

"Getting the transmitters will be easy," said Haines. "After we shut off the station, we'll just bomb the mountain masts out of action."

Burl choked. "Why, it never occurred to me, but why can't we bomb the station from the air? One atomic bomb should finish it off." He almost added, And you wouldn't have needed me after all, but squashed the thought. He wouldn't have given up coming along for anything, he now realized.

"There's a distortion, as there was at the Andes station, that would make it hard to hit. But I imagine we could do it if we tried hard enough. But that isn't what we want at first. It's important, very important, that we get pictures and details of this station from inside. We can't just break up the enemy installations—we've got to learn from them, we must find out how they do it and how we can use it." This was Lockhart speaking. "You'd better start the job," he added to Haines. "Are you ready?"

Haines nodded reluctantly. "Yep," and turning to the three who would accompany him, he ordered, "let's go."

The four explorers gathered near the exit port. They had put on space suits and strapped on various items of equipment, weapons and work tools. They passed through the airlock into the cargo section of the ship. Communicating through the helmet radios, Haines directed each what to do, and also directed Lockhart where to bring the ship for the landing.

Burl heard Lockhart's voice warn them that he did not want to hold the ship too long over the sunny hot side. "We've already noticed a buildup of heat from the solar radiation on the skin. And the heat radiating from Mercury is accumulating too fast. We can't get rid of it if both sides of this ship are going to be heated up. As soon as you make your landing, I'm taking the ship back to the cold side."

"Uh huh," came Haines's voice. "We don't want to hang around here any too long, either."

Then the four, as prearranged, unlimbered the work rocket they had picked. There were several sizes of small exploration craft. They had at first thought of the tractor—an enclosed, airtight truck on tractor wheels which could crawl up to the station while the men inside it were protected by air conditioning. But a quick survey showed that it would overheat too fast and might easily bog down in one of the many soft spots. So they took the four-man, rocket-propelled cargo plane instead.

The ship was airtight and pressurized. They had taken every precaution. The four piled in with their supplies. Then, as the Magellan swooped momentarily lower, the escape hatch opened and, with Ferrati at the controls, the rocket plane shot out with a roar of its exhausts.

They raced low over the burning landscape, and before them the wide, dark, forbidding canyon cut its way through the plain. It was into this canyon that the rocket plunged.

The precipitous rocky sides rose above them, and suddenly they were in darkness. Immediately, the plane's cooling system became more effective as Ferrati guided the rocket through the shadowy depths away from the blazing sunbeams. Burl saw, by means of the radar, that the bottom of the heat crack was many miles down.

They raced along the crevice until they reached the mountain chain. Here, Ferrati abruptly raised the nose of the plane and they shot upward, popping out of the shadow into the sunlight.

Before them loomed the hard unbroken walls of the Sun-tap station. The rocket plane came to a stop a hundred feet away.

As soon as it had halted, Burl and Ferrati leaped out, with white sheets thrown over their suits to afford some extra protection from the Sun's rays. Between them they carried a long, awkward affair of poles and plastic.

Burl's feet touched the ground; through the cushioned leather of his thick boots he felt the heat just as if he had stepped on a hot stove. He moved quickly, and as they had rehearsed, he and the explorer slapped the rig together and set up a gleaming plastic skin sunbreak to shield the rocket plane. The plastic sheets reflected the Sun's heat and cut off a fair portion of the direct radiation which would otherwise have rendered the rocket plane inoperable and uninhabitable in short order.

While they were assembling the sunbreak, Haines and Boulton unloaded a portable antitank rocket launcher. With no wasted motion, Boulton aimed the launcher at the wall, and Haines thrust a long, wicked-looking rocket projectile into the tube. There was a flash of soundless fire and a line of dissipating white smoke. Nothing could be heard in the airlessness.

Burl felt the shock through the ground as the shell hit. A chunk of the wall ripped apart and collapsed.

As quickly as he saw it, Burl acted. Haines's voice rang in his ear, but already Burl was in action. Back into the rocket plane, out again with—an umbrella!

He made a flying leap toward the Sun-tap station. He felt terrifically strong in the slight gravity, and the leap carried him thirty feet forward. As he slid through the space above the surface, he opened the umbrella. Its outer side had been painted white, and partly shielded him from the direct heat. He made the station in five leaps and climbed through the broken wall. Boulton followed him with another umbrella and a pack under his arm.

Inside the station it was cool—the walls had been high enough to create shade within. It was like the station in the Andes, but bigger, much bigger.

Boulton joined him, folded his umbrella calmly, and yanked an air-compression pistol from his belt. "See anyone?" he asked.

"No."

Burl remembered then that there could possibly be a living guard at this station. They searched carefully, but there was no sign of life. Boulton was doing a soldier's job, that was all.

While Boulton set up his photographic equipment, Burl made his way around the shining globes and strange tubes that were the nerve center of the station. He finally found the same type of control panel that he had found in the Andes station.

He hesitated before it, wondering if, after all, this, the original charge, would work. He hoped that there might be another charger globe available, but saw none. It would be up to him.

He put a gloved hand on the control. Perhaps, he worried, the charge would not conduct through the insulated, cooled material of his suit. He pushed the levers, and knew then that it did.

The pulsing of the spheres halted. There was a sharp dip in the faint vibration he had been feeling in his feet. He shoved the levers all the way, and suddenly the station went dead. Above him, one of the great discs atop its mast snapped and burst apart under what must have become an impossible concentration of power without a channel for outlet.

"Sun-tap Station Mercury is dead," Burl said quietly into his helmet phone.

At that very instant a distant globe, perched on a pedestal against the wall away from the rest of the equipment, flared a brilliant red.

In an artificially constructed chamber somewhere in the solar system, an intelligent being sat before a bank of instruments that was designed to bring to his attention various factors concerning the things that mattered to his species. This being had been on duty for the average length of time such a duty entailed and had been paying little conscious attention to the routine—for there had been nothing to report for some time.

The drop in channeling from Planet III that had occurred some time ago had thus far not caused too much concern. It was assumed by the other intelligent beings involved that the matter was possibly a weather condition, a volcanic discharge or quite simply that the planet was in unfavorable orbit. Not all the stations ever worked simultaneously. There were always some behind the Sun, or blocked in some other manner. But the main channels were at work, and the different lines and shifts continued to build up satisfactorily.

But now something occurred that focused the attention of the watcher more closely on his instruments. A facet of his panel had flashed a color at the lowest end of his visible spectrum. How the being registered that color cannot be said; the inhabitants of Planet III would have termed it red.

With trained reaction, the watcher activated the full signal. Instantly there appeared before his eyes a vision of a scene. There was the interior of the major station on Planet I. It was non-functioning, and there were two strange creatures turning now to look directly at him. They were bipeds with two armlike extensions, lumpy objects, clad in bulky white folds. They wore cumbersome helmets and he could see two eyes shielded beneath thick transparencies over the face.

One of these creatures raised his arm and there was a puff of steam. Then the vision flashed off, but not before the trained watcher had activated the crash mechanism.

If the watcher had been closer in space to the station, the destruction would have come quicker. Unfortunately for him, the speed of light and radio impulses is limited, so that it was several minutes before the destruction impulse reached Planet I.

A short while later, after the guiding beings had digested the news, preparations were made for a vessel to go sunward to investigate—and remove—the interference.

Burl twisted on his heel sharply as he whirled around to look at the flash of red. Boulton drew his hand weapon, aimed and fired.

There was a jet of steam as the compressed air blasted the dart from the gun. The glowing globe was pierced, there was a small explosion, and then the globe and its pedestal vanished.

"What was that?" cried Burl.

Boulton holstered his gun. "A signal of some kind—a warning probably. My guess is that it was an alarm tipping off the remote control masters of this place that it was out of commission. Help me with the photo stuff; I think we'd better get out of here quick!"

Without wasting more time, the two men snapped the scene as fast as the shutters would click. Then they picked up the cameras, grabbed their umbrellas and ran for the break in the wall.

Just as they made their first flying leaps toward the shielded rocket plane, the globes within the Sun-tap station started to go off. One after another, like a chain reaction, they blew up, and within seconds the interior of the walled station was a turmoil of falling metals, beams, wires, and sharp transparent shards.

Haines and Ferrati were ready for take-off and puffs of smoke were coming from the exhaust. Without bothering to take down the plastic Sun-shield, Burl and Boulton tumbled into the cabin. Before the door was even closed, Haines lifted the ship and headed for the dark depths of the canyon.

The inside of the plane was perilously hot. The shield had been a temporary protection, but even the ground radiated heat like an oven. They had to seek the cold of the sunless canyon to allow some of the heat to escape. To have flown directly to the Magellan without cooling the plane would have been disastrous.

The Magellan emerged from the cold side to meet them. From the heights of space, they saw that they would not need to bomb the mountain relayer masts—for the same alarm that had triggered the station had shattered them.

After the Magellan had scuttled back to the cold side, there was a council of war in the control room. Burl and Boulton described very carefully what had happened.

"This must have been their primary station," said Russ thoughtfully. "No matter what they seek to channel from the Sun on other planets, it is from here that the first and strongest diversion of solar energy must have been coming. This station may have been the last constructed—the final link put into place. And for that reason, they installed an alarm."

"Ah," said Lockhart, "even if they did, would it necessarily have destroyed the station? After all, they would normally have figured on repairing whatever went wrong."

"It seems to me," said Burl, "that the red flash itself didn't start the destruction. There was a delay—must have been several minutes—before it started. Could it be, that what was alerted was a watcher?"

"Where?" said Boulton. "There was no place for a watcher to be in that station. We saw no sign of it."

"Maybe deep underground?" suggested the engineer, Caton. "They might have living quarters a few miles underneath."

"Highly unlikely," said Russ Clyde. "It would still be too hot, and, remember, these people plan to incinerate Mercury and the inner planets. They must be from the edge of the system. The delay may be a valuable clue to that. It would take time for a remote control station on another planet to see what was happening and take steps. If you can figure out exactly how many minutes and seconds elapsed between the flashing of the red bulb and the blowup, we could work out the approximate distance."

But, unfortunately, the time could not be judged that accurately. Neither Burl nor Boulton had had time to look at his watch.

They hung over the cold side of Mercury for several hours more while the two astronomers figured their next move. When the orbits had been determined, the Magellan turned its massive wide nose away from the Sun toward a gleaming white disc that dominated the dark skies of outer space. With full power on, they pushed away from the littlest planet and began the long fall toward the Sun's second planet, that which some had considered to be Earth's veiled twin, Venus.

There was a matter of thirty million miles to cross, and the crossing would be made fighting the pull of the Sun all the way.

Caton and his men had spent the wait on Mercury working on the great generators in the powerhouse nose. They recalibrated the output and corrected it from the records kept during the flight inward. Now they were confident of its ability to drive the ship away from the Sun. Coming in, they had not been sure what their A-G drive would do and could do. Going outward they knew just what to expect.

They did not travel blindly outward, for that would have been both a crude waste of power and inaccurate. Instead, the ship drove at a long slant from the Sun, moving in a gently curving orbit that would bring it onto Venus at the same time that Venus itself was moving along in its orbit. This is what they had tried to do before, but without success. Venus travels around the Sun at a speed of about 32 miles per second, and takes about 224.5 days to complete the circuit. From where the Magellan took off, it would approach and overtake Venus at a speed a little greater than the 32 miles per second.

The days passed swiftly enough. They had developed the pictures taken in the Mercury station, and the engineers and astronomers spent long hours debating their features, matching up what they had seen with what was known about the Andes station.

The shining face of Venus grew larger. It was a mysterious planet, the most mysterious in the system, even though it was the closest of the planets to Earth. Venus was a world whose atmosphere—of Earthly depth—was a solid mass of clouds. Never had the clouds lifted to reveal the surface. The clouds reflected the sunlight brilliantly, yet as Burl could now see with the naked eye, parts of it were hazy, as if mighty storms were raising dark particles from below.

"We've had a couple of prober rockets shot into its surface," said Russ, as they watched the oncoming planet. "They didn't prove much—faded out fast, but we think they established its length of day. Nobody knew how many hours it took Venus to rotate on its axis. Some even thought it always presented one face to the Sun as does Mercury. Others thought it had a quick day, shorter than Earth's. Others gave it a day almost a month long.

"Our prober rockets, carrying unmanned instruments, rather definitely indicate that the planet has a day about twenty Earth-days long. Even though it's shielded by the clouds, it must be miserably hot near the surface."

"We'll soon find out." Burl grinned. "After Mercury, it couldn't be so bad. Maybe it rains all the time."

Russ shrugged. "Who knows?" he said.

Venus was a vast sea of swirling white and gray clouds beneath them when the Magellan reached it. They hung above the cloud level, while stretching below them lay the circular bowl of veiled mystery that was the fabled evening star of poem and song.

Oberfield was probing the surface with the radiation counters for the Sun-tap distortion. None had been detected from Earth, but observation of the sunny face of Venus had always been difficult from the third planetary orbit. But quickly the dour astronomer proved the fact. A calculation of the planet's albedo—its rate of reflected sunlight—showed that in one large central section there was a dimming out. Somewhere in that spot, the light was being diverted.

Lockhart brought the Magellan down gradually, closer, closer, and finally sank it into the soupy atmosphere of Venus. Now, from every viewplate, nothing reflected but a glare of white mist. But the ship was not operating blind. Radar pierced the clouds, and from the wide screens the crew could see that they had not yet touched the surface.

"Watch out for mountains," whispered Russ, hanging over Lockhart's shoulder.

Their progress was slow but steady. The cloud bank around them did not clear, but still glowed gray. After a descent of nearly two hours, there was a flicker on the radar. It registered no features, no mountains, nothing but a seemingly flat plain.

Above and around them the white clouds still blanketed everything. But now Burl thought he saw a pale glow. Gradually the white faded away into wisps and shreds, and in a flash the ship broke out of the clouds.

They hung beneath a grayish-white sky. Below them, scarcely a half mile of visibility in misty, thin air, they saw the surface of Venus. They were over water. An ocean stretched below them as far as the eye could see, with neither a rock nor an island. Venus was a water world!

The Magellan hung in the air while the men studied the surface of this world that had so long been a mystery. The air was not the clear air of Earth; rather, it was the kind that precedes the coming of a fog, thick, heavy with moisture, the horizons fading into gray. Below them lay a mottled expanse of water, reflecting the gray sky, and verging almost to a deep brown. The water was still, occasionally stirred by a slight wave. "No tides have ever moved these waters," commented Russ quietly to Burl. "There is no moon to pull and sway them. The motion of this world, so slow in the passage of its day, hardly disturbs the water."

"It looks shallow to me," said Burl. "The darker sections look as if the bottom must be close."

"I imagine it is. We'll take soundings," Russ answered. "I have a feeling the whole world may be like this ... one vast, shallow, swampy sea. See the scum floating on it?"

"See it? Now that you mention it, there's hardly a part that hasn't something on it," was Burl's reply. "There're patches of muck all over it, like floating oil, or even drifting masses of weeds."

It was true. The water showed on its surface a strange filth unlike anything one would expect on the surface of a Terrestrial sea. There were wide areas of brownish-gray slime and little floating blobs of green. Shining flecks of yellow, like bright oil drops, seemed to flow through and between the masses of scum.

At the radar, Haines began to call out figures. As Russ had guessed, it was a shallow sea. In places, the bottom was only a dozen feet beneath. For a while, all the men of the crew were quiet, watching the silent waters beneath them.

"Unclean, the whole place looks unclean," Lockhart said finally. "We've got work to do. Let's find the Sun-tap station."

The rest of the crew came to action. The spaceship began to move slowly, while Oberfield and Caton probed for the lines of force which would lead to the station.

Now a long, low bank appeared, a ridge of mud protruding above the water. Here and there stretched other low mud bars, and once a ridge of rock.

"I've seen no animals or birds," said Burl. "Do you suppose there are any?"

Russ pursed his lips. "I don't think so. From the look of this world, life probably isn't developed that far. You won't find animals until there is dry land—and I'd guess now that there's no place on all Venus where there is much dry land. There may be fish or fish life, but even that's questionable. Consider—the long, long day, the absence of violent, unshielded Sun rays, the steady damp warmth, the quiet, barely moving waters, the heavy amounts of carbon dioxide in the air...."

He paused and went over to Lockhart's chart table to pick up a paper. "Oberfield worked out the atmosphere. It is very heavy in carbon dioxide, very low in free oxygen. There's water vapor down here, but the clouds have kept it below; it didn't show up in the outer atmosphere at all."

"There's the Sun-tap base," said Burl, and added as an afterthought, "I think."

This one did not look at all like the other stations he had seen. There was indeed a ringed wall station, but the wall was low and slanted outward. It stood on the end of a wide mudbank, and near it veins of rock glistened as if wet.

The interior machinery was a neat, compact mass of crystalline globes and levers. But the masts and shining discs which had characterized the stations on Mercury and Earth were missing. Instead, there floated upon the surface of the water, for a mile around, great shining bowls, like huge saucers gently rocking in the faint wavelets. Thin, flexible, shining lines of metal connected this surface layout with the station.

"With no direct Sun to aim at, this station seems to be directed toward a nonfocused system of light diversion," Lockhart announced. "The wrecking crew please get under way!"

"I'm going down with you," Russ joined in. "I've gotten permission to take some observations from the surface."

"Good," said Burl, and hurried with him down to the central floor.

They disembarked in two parties. Haines and Ferrati used the two-man rocket plane and would make a wide encirclement of the vicinity, mapping and finally blowing up the accumulator discs floating on the surface. Burl, Russ, and Boulton took a helicopter.

The helicopter, under the control of the Marine captain, dropped out of the cargo port of the Magellan. Steadied by the regular whirl of its great blades and driven by tiny rocket jets in the tip of each wing, the whirlybird swung down like a huge mosquito hovering over a swamp patch.

It moved over the water and finally hung directly over the mudbank. Maneuvering so that the helicopter was directly in the protected circle of the walls, Burl and Russ dropped a rope ladder and swung down hand over hand to be the first human beings to set foot on Venus.

They were lightly dressed, for the temperature was hot, around 110°, and it was humid. No breezes blew here. They wore shorts and shirts and high-laced leather boots. Each carried two small tanks of oxygen on his back. A leather mouth nozzle strapped across the shoulders guaranteed a steady flow of breathable air. In their belts were strapped knives and army pistols. Russ carried recording equipment, and Burl a hatchet.

They dropped off the swaying ladder inside the station. The ground was hard-packed as if the builders had beaten it down and smoothed it off. The globes were familiar to Burl—he had studied the pictures of the two he had already visited and he realized that they followed the same general system. Where the mast towers would have been, there were leads running through the plastic walls out across the sea. He wondered briefly why the walls were curved outward.

As the helicopter moved away, the metal weight on the end of the dangling ladder brushed the top of the wall. There was a crackling noise, and a spark jumped between them.

"The wall is electrically charged," said Burl. "I wonder why?"

Russ shook his head. "From the looks of it, to keep off something. Perhaps some kind of native life. But what? I'm sure there's nothing of a highly organized physical structure here."

Burl found the controls of the station, but before touching them, he remembered the alarm on Mercury. "I'd better try to smash the alarm first," he called out to Russ.

Finally, Burl located an isolated globe perched on a post, which resembled the one he had briefly glimpsed on Mercury. He ran his hands over it, feeling a mild vibration within. Then, at its base, he found the levers. He moved them and the vibration died out. "I think I've turned it off," he announced. "But stand by with a gun, just in case."

Russ drew his pistol, and Burl switched off the main controls of the Sun-tap. A globe or two burst; there was a sort of settling down in the station. Abruptly they felt the heat intensify and knew that the sky was shining more brilliantly than before. The diversion of the Sun was over for Venus.

The alarm globe remained quiet, but Burl took his hatchet and smashed it. Russ was carefully photographing the station, measuring the distances, and tracing the lines. Overhead, the wide blades of the helicopter flapped around and around, accompanied by little hissing puffs of rocket smoke. They could see Boulton looking down at them from the tiny cabin.

Russ was scooping up bits of soil to bring back for analysis when he saw what seemed to be a wet patch on top of the wall. As he watched, it spread until it reached the bottom. In a remarkably short time a whole section of wall was gleaming wet. A patch of damp oiliness spread over the floor.

"This I've got to get a sample of," said the rusty-haired astronomer. He reached for a sampling bottle in his pocket, and at the same time the patch of wetness spread to his shoes.

As Russ stepped forward, there was a sucking sound, and he lifted a thick gummy mass that was stuck to his sole. He shook his foot, set it down, and lifted the other, but it, too, was imbedded in thick slime. The stuff now was running up his ankle.

"Hey!" he called out, and swung one foot vigorously to free it. More swiftly than he could move, the whole patch slid down the wall and swept around him. It was moving up his legs, as if trying to envelop him.

"It's alive!" he shouted, and grabbed for the knife in his belt. In vain he tried to slash out. "It's like a giant amoeba that engulfs its food! Get it off me!"

But the knife was ineffective. He fired his pistol, but the thing was just a vast wide puddle of slime, without brain, heart or organ that could be harmed. The soles of Russ's boots were already half eaten away and his socks were going fast. Some of it was touching the skin of his knees.

He screamed as the stuff burned him.

Burl had joined the attack with his knife, but leaped back when that proved useless. His mind raced for a way to help. Above them, Boulton was swinging the helicopter down so Russ could hoist himself out of harm's way, but time would not permit it. In another instant the mass would have Russ.

Burl grabbed at the straps crossing his shoulder and swung the two oxygen tanks from his back. He snatched one from its leather holster, and pointed its nozzle at the mass of slime. He turned the stream of oxygen on, and then, taking his pistol, held its muzzle in the jet of oxygen and fired it.

The roar of the gun was matched by the roar of a stream of fire that shot from the tank. Wherever the burning jet of oxygen touched, the mass shriveled and blackened. Yards and yards of amoeba seemed to writhe, hump upward in agony, and pull away.

There was a ring of burned white along the ground, a sickening smell in the air, but the thing was dead.

Russell Clyde grabbed the ladder as it swung toward him, and climbed up. The soles of his boots were gone and the sides were strings of raw, half-eaten leather. His legs and knees bore ugly patches of red where the slime had touched.

"Well done!" called Boulton to Burl from the cabin. "Come on up before something else comes along!"

Burl grabbed the ladder. He took two steps on the swaying, swinging rope as the helicopter started to climb and suddenly he felt himself losing strength. He became dizzy and tried to hold on, but began to lose consciousness. Dimly he heard Boulton yell at him, "The oxygen, the other tank, turn it on!"

The second tank was still dangling from his chest.

Fighting for consciousness, Burl twisted the nozzle. There was a hiss and he felt air blow against him. Miraculously, his senses cleared, and holding the oxygen tank tight against him, he climbed up the ladder and into the safety of the helicopter.