The Web Between the Worlds

by Charles Sheffield

  Galley and Regulo were at the computer, working together on the computation of the drive placings. As volatiles were consumed and expelled in flight, the center of mass and moments of inertia of the remaining rock would change. The drive thrust had to remain exactly through the changing center of mass, or the whole planetoid would begin to rotate under the applied torque.

  “See now why I’m against your damned hyperbolic fly-by?” grumbled Galley. “When you send anything that close to the Sun, the boil-off rate goes crazy. You lose a good fraction of your volatiles in just a few hours if you go in near enough. That’s going to ruin the center-of-mass calculation. We never run into that sort of problem with an elliptic transfer, but now we have to think about it.”

  “We can allow for it,” said Regulo. His voice was confident. “It’s just a matter of a little more calculation. I’ll work out the solar flux as a function of our time in orbit, and that will give us all the boil-off information that we need.”

  “Oh, I’m not saying we can’t do it.” Alexis Galley shook his head. “Only that it’s a pain, and we’ll lose another day while we’re at it.”

  “Look, I’m not asking you to do it. I’ll be quite happy to handle all the computation.”

  The older man looked at Regulo calmly. “Now then, Darius, just cool off. I’m not saying you don’t take your share of the work, and more. I’m just saying that I still don’t care for this whole thing. I’ve only flown one hyperbolic in my whole life, and that was in an emergency medical ship with unlimited thrust. We weren’t trying to steer a billion tons of rock along with us, either. This is a tricky business, one you don’t jump into without a decent amount of thought. If you’re going to work on the calculations, I’ll go out on the rock and take another look at the position of the drive placings.”

  “I’d like to help on that, too. I’ve never seen it done before, and I want to learn how. Don’t worry about the boil-off calculations,” Regulo added quickly, seeing Galley’s doubtful look. “I’ll work those up as soon as we come back into the ship.”

  “All right.” Galley paused for a second, then nodded his head approvingly. “I’ll say this for you, Darius, I’ve never had a junior man as keen to learn every single thing about this business. Come on, let’s get our suits on. Time’s a-running.”

  The Alberich was moored on a short cable, a few meters from the asteroid. The difference in the natural orbits of the two bodies was infinitesimal, barely enough to hold the tether taut. The two men drifted slowly across to the rock and Galley began his careful examination of its surface.

  “Here’s a good example,” he said after a few moments, his voice loud over the suit phone. “When you first look at this location you think it’s perfect. There’s solid rock to secure a drive to, and you can see the volatiles right on the surface. But take a look at the mass distribution.” Galley flashed part of the computed interior structure of the planetoid onto the suit video. “See that? The volatiles peter out just a few meters below the surface. Now, compare it with that position over to sunward. There’s a real vein of volatiles there, and the mooring is just as good.” Galley peered closely at the cratered surface, lit by the harsh, slanting rays of the distant Sun. “This looks like a fine one. There’s enough reaction mass in that vein to do us some real good.”

  Regulo was studying the video display. “I thought you told me that this mass distribution was just an approximation.”

  “It is.” Galley gave a brief bark of a laugh. “Sometimes you get a surprise, no matter how much thinking you do ahead of time. But the approximation is still the best information we have, so there’s no sense in ignoring it unless we actually see something on the surface to tell us more. That’s one reason we came out here.” Galley switched in the ship’s circuit. “Nita? Give us that composition read-out, would you?”

  He bent forward while the signal was being read through to the suits, and tapped the rock close to their feet. “Here’s an example of what I was saying. I know there’s a good amount of ferromagnetics under us, just from the strength of the magnetic clamps in the suit. You couldn’t see that from the data we have on the ship, right? I don’t know what else we’ve got here, either. I’d hate to throw away a lump of platinum, just to make a hole setting for a drive.”

  The two men moved slowly across the surface of the rock, examining each possible site carefully while Galley offered a running commentary on his selection logic. It took a long time, and almost four hours passed before Alexis Galley picked the last of the seven places that he wanted. He patiently answered Regulo’s continuous stream of questions.

  “We don’t usually need to be this careful,” he said. “But this one’s an awkward shape — too long and thin.”

  “You’re afraid it might start to tumble?”

  “It has that tendency. The closer the shape of the rock to spherical, the less we have to worry about rotational instabilities. This one is almost twice as long as it is wide. We’ll be all right, though. With those drive placings, we’ll have no problem unless you find really big values for the boil-off mass. I’ll be interested to see what the temperatures run out here during perihelion fly-by. Up near the thousand mark, for my guess.”

  The two men had begun to drift slowly back towards the Alberich. Regulo noted the easy control of small body movements and the tiny, almost unconscious use of the suit jets as Alexis Galley controlled his position and attitude. He did his best to mimic the older man’s actions.

  “Fly-by will go really fast,” he said. “I don’t think we’ll spend more than two weeks inside the orbit of Mercury, in-bound and out-bound. The rock will get hot, but there’s no harm in that — and it won’t be for long.”

  He turned his head and stared through the faceplate of the suit at the distant Sun. Still two hundred and fifty million miles away, it seemed small and strange, a dazzling, golden ornament in the black sky. Galley had stopped and was following his look.

  “Come on, Darius,” he grunted. “You’ll be getting your belly-full of that in another month or two. Let’s get those calculations done and see to the drives. After that, you’ll have all the time in the world for Sun-watching. But I have to say, the sooner we get through with this whole thing and are in Earth orbit, the better I’ll be pleased.”

  CHAPTER 4: “Busy old fool, unruly Sun…”

  The drives set in the surface of the asteroid had finished their first spell of work long ago. Now they sat idle. They would not be needed again until the time came to decelerate into Earth orbit. The Alberich, still tethered to the rock, was falling with it, steadily and ever faster, toward the Sun. They were past Venus, past Mercury, plunging to perihelion. Darius Regulo, magnetic clamps holding him firmly to the surface of the planetoid, paused in his work to take a quick look at the solar primary. It had swollen steadily since they left the Asteroid Belt. Now it was ten times its former size and dominated the sky.

  “Come on, move it.” Nita’s voice came suddenly over the suit phone. She must have been watching on the external viewing screen. “Don’t hang about out there. We’ll be separating the Alberich from the asteroid in less than two hours.”

  “On our way,” Regulo said. “I just finished checking the last drive. They’ve all come through first impulse well. Unless Alexis disagrees with some of my data, I don’t see a reason to change any of the settings before we use them again.” He looked closely at the rock surface beneath his feet. “I’d say we’re getting about our predicted amount of boil-off from the surface here.”

  “And it’s getting hotter than hell.” That was Galley’s voice, grumbling over the suit circuit. He was standing on the rock, close to the tether point that connected the Alberich to the asteroid. “I’m showing contact temperatures of over five hundred Kelvins, going up every minute. Come on, Darius, put the lid on it and let’s get out of here.”

  “I’ll be right with you.” Regulo bent to clamp the protective cover over the last of the drive units. It was a little tricky gettin
g the fit to the asteroid’s rough surface. He crouched lower, frowning at the awkward bolts.

  He was carefully turning the last coupling when the tremor came. His attention was all on the clamp and he saw nothing — but the rock surface was suddenly shaking beneath his feet. Even as he felt the vibration, he knew that it was impossible. Earthquakes simply don’t happen on tiny rock fragments only a couple of kilometers across.

  He straightened, and at the same moment there was a long, metallic screech over his suit phone. The Sun, which a moment ago had been shining in fiercely through his faceplate, was abruptly darkened by an obscuring cloud. He looked for the Alberich but it too had vanished within a glowing white nimbus.

  “Alexis! What’s going on?”

  He waited. There was no reply over his phone. After a few seconds he saw the shape of the ship, appearing mysteriously through the fog. The fog. There could be no fog here, far from any possible form of atmosphere. Regulo set his course for the ship, using his jets as Alexis Galley had taught him. As he moved, his eyes scanned the surface of the rock looking for Galley himself. The other man had to be somewhere on the asteroid. There was no sign of him, but before Regulo was halfway to the ship tether point he was beginning to see a slight change to the familiar shape of the surface. Where he had last seen Galley there now stood a deep pit, gouged into the rock itself. A fuming gas, brightly lit by the glaring beams of the swollen Sun, was pouring out of its interior.

  The Alberich was still attached to the rock by its tether. Regulo propelled himself up to it and looked in dismay at the condition of the ship. The forward hull plates had been shattered, with a great boulder of dark rock embedded in the wall of the main cabin. He looked in through a broken port and saw Nita Lubin’s body, unsuited, floating free against an inner bulkhead.

  Even while his mind was struggling to accept the reality of an impossible series of events, some deep faculty was coolly assessing all that he saw and seeking explanations. He looked for an instant at the face of the Sun. The photo-sensitive faceplate of the suit darkened immediately, so that he could see nothing in the whole universe but that broad and burning face. The Alberich and its cargo were still falling towards it at better than thirty miles a second.

  What were the last words he had heard from Alexis Galley? …over five hundred Kelvins, going up every minute. Somehow, that had to be the key. A hundred and thirty degrees above the boiling point of water, almost four hundred degrees above the boiling point of methane. The surface of the asteroid had been cooking hotter and hotter in that unrelenting Sun, vaporizing the volatiles beneath. The pressure of the trapped gases forming there had increased and increased… until at last some critical value had been reached. Part of the rock had fractured under the intolerable stress. Fragments had been propelled out by the expanding gases, into the body of Alexis Galley, into the hanging target of the Alberich. All that had saved Regulo had been luck, his position on the asteroid and distance from the explosion.

  But saved for what? Regulo looked about him with a sickening realization of his own plight. The ship was a total wreck, he had known that as soon as he saw it. There was no way that it could be powered up to take him away to a safe orbit. The automatic alarm system should have triggered as soon as the ship’s internal condition became unable to support human life. Regulo tuned quickly to the distress frequencies and heard the electronic scream as the ship blared and roared its high-frequency Mayday across the System. The signal would already be activating the monitors far out beyond Mercury, but that would be of no use to him. When the ship had swung past the Sun and out to the cooler regions of the Inner System, others would come and recover the hulk and its valuable cargo. But that would be too late for Regulo. At the moment, the Alberich was as unreachable by outside assistance as if it were sitting on the blinding photosphere of the Sun itself.

  After those first few moments of animal panic, Darius Regulo steadied. In spite of the furnace looming ahead of him, he felt cool and analytical. What were his options?

  The Alberich was available — but he had calculated long since that the ship’s refrigeration system could not support a tolerable temperature through a perihelion transit of two and a quarter million kilometers. If he stayed with the ship he would quietly broil to death. He stared again at the Sun. Already it seemed bigger than ever before. In imagination, those fierce rays were lancing through his puny suit, pushing his refrigeration system inexorably towards its final overload. He could feel sweat trickling down his neck and chest, the body’s own primitive protest at the worsening conditions surrounding it.

  He could open the suit and end it now. That would be a quicker and more merciful death, but he was not ready for it.

  Regulo entered the Alberich through its useless air lock. First he went to the communicator and sent out to the listening emergency stations a brief and precise description of his situation. He added a summary of what he intended to do, then went to the supply lockers and took out an armful of air tanks, jet packs, and emergency rations. The latter, he felt, had to be thought of as an expression of optimism. From the medical locker he took all the stimulants that he could find.

  He performed a brief calculation on his suit computer, confirming his first estimate. Somehow he would have to survive for eight days. If he could do that, perihelion would be well past and the Alberich again cool enough to tolerate.

  Dragging the bundle of supplies along behind him, Regulo left the ship and propelled himself slowly back to the asteroid. The explosion that destroyed the Alberich and killed Alexis and Nita had expelled enough material from the rock to give it some angular momentum. It was turning slowly about its shortest axis. Regulo attached the supplies firmly to his suit, took a last look at the ruined ship, then went behind the rock and entered the deep, black shadow. He knew what he had to do. At three million kilometers, the Sun would stretch across more than twenty-five degrees of the sky. He had to stay close enough to the surface to remain within the shield of the cool umbra. That was his only protection against the roaring furnace on the other side of the asteroid.

  He felt cooler as soon as he passed into the shadow. That, he knew, was all psychological. It would take several minutes before his suit temperature dropped enough to make a perceptible difference.

  As he expected, there were first of all several hours of experiment. If he ventured too far from the surface, he lost the protection of the cone of shadow. Too close, and he was forced to move outward when the long axis of the asymmetrical rock swung around towards him in its steady rotation. He found the pattern of movements that would minimize his use of the jet packs and settled in for a long, lonely siege.

  There was ample time to look back and study the mistakes that they had made. With such a close swing-by of the Sun, they should have kept the rock turning. That would have given an even heating on all sides and also a chance for heat to radiate away again into space. And they should have put the Alberich at least a few kilometers away from the asteroid, to reduce its vulnerability to accidents. Regulo reached a grim conclusion. Alexis Galley had been right: with all his experience, he had not known how to handle the hyperbolic swing-by. Regulo would learn that — if he survived.

  After the first twelve hours his actions became automatic. Move always to keep in the shadow. Eat and drink a little — he had to force himself to do that, because his appetite was gone completely. Check the fuel in the jet assembly. And take a stimulant every six hours.

  He could not afford to sleep. Not with the menace of the Sun so ready to engulf him if he failed to hide from it. But sleep was the tempter. After sixty hours his whole body ached for it with a physical lust that surpassed any desire he had ever felt. The stimulants forced the mind to remain awake, but they did so without the body’s consent. Fatigue crushed him, sucked the marrow from his bones, drained his blood.

  After eighty-five hours he began to hallucinate. Alexis and Nita were hanging there next to him, unsuited. Their empty eyes were full of reproach as they floa
ted out into the golden sunlight and waved and beckoned for him to follow them, to leave the dead shadows.

  Soon after the hundredth hour, he fell briefly asleep. The flood of molten gold wakened him, splashing in through his faceplate. He had drifted outside the guardian shadow of the asteroid, and although his visor had darkened to its maximum it was useless against the stabbing, shattering light. He squeezed his eyes shut. The orb was still visible, burning a bloody, awful red through his eyelids.

  He must be close to perihelion. The Sun had become a giant torch surrounded by huge hydrogen flares. The asteroid had dipped well inside the solar corona itself, hurtling in to its point of closest approach. Light filled the world. Regulo writhed in its grip, turning desperately about to seek the shelter of the rock. The asteroid, the stars, the ship, all were invisible now, forced to insignificance by the tyrannous power of the great solar crucible.

  Instinctively, Regulo began to jet back and forth, firing his thrusts at random in a desperate cast for the shadow. At last he found it by pure luck, a dark crescent bitten from the flaring disc. He moved towards it. Back once more in the blessed darkness, he hung seared and gasping in his overloaded suit.

  “No.” His voice was hoarse and choking. “Not this time, you bastard. You don’t get me this time.” He glared through bloodshot eyes at the surface of the asteroid, as though seeing right through it to the burning orb beyond. “You won’t get me. Ever. You think you’re the boss of everything, but I’ll prove you’re not. I’ll beat you. I’ll outlast you.”