Perilous Planets

by Brian Aldiss

  He contacted me in New York and he was very casual at first. We spent an evening here at the Red Lion, talking about old times; he told me about the Vulcan business, and how he’d been out to see Sanderson and the Twilight Lab on Mercury, and how he preferred a hot trek to a cold one any day of the year—and then he wanted to know what I’d been doing since Venus and what my plans were.

  ‘No particular plans,’ I told him. ‘Why?’

  He looked me oven ‘How much do you weigh, Peter?’

  I told him one-thirty-five.

  ‘That much!’ he said. ‘Well, there can’t be much fat on you, at any rate. How do you take heat?’

  ‘You should know,’ I said. ‘Venus was no icebox.’

  ‘No, I mean real heat.’

  Then I began to get it.’ Your’re planning a trip.’

  ‘That’s right. A hot trip.’ He grinned at me. ‘Might be dangerous, too.’

  ‘What trip?’

  ‘Brightside of Mercury,’ the Major said.

  I whistled cautiously. ‘At aphelion?’

  He threw his head back. ‘Why try a Crossing at aphelion? What have you done then? Four thousand miles of butcherous heat, just to have some joker come along, use your data and drum you out of the glory by crossing at perihelion forty-four days later? No, thanks. I want the Brightside without any nonsense about it.’ He leaned across me eagerly. ‘I want to make a Crossing at perihelion and I want to cross on the surface. If a man can do that, he’s got Mercury. Until then, nobody’s got Mercury. I want Mercury—but I’ll need help getting it.’

  I’d thought of it a thousand times and never dared consider it. Nobody had, since Wyatt and Carpenter disappeared. Mercury turns on its axis in the same time that it wheels around the Sun, which means that the Brightside is always facing in. That makes the Brightside of Mercury at perihelion the hottest place in the Solar System, with one single exception: the surface of the Sun itself.

  It would be a hellish trek. Only a few men had ever learned just how hellish and they never came back to tell about it. It was a real hell’s Crossing, but someday, I thought, somebody would cross it.

  I wanted to be along.

  ==========

  The twilight lab, near the northern pole of Mercury, was the obvious jumping-off place. The setup there wasn’t very extensive—a rocket landing, the labs and quarters for Sanderson’s crew sunk deep into the crust, and the tower that housed the Solar ‘scope that Sanderson had built up there ten years before.

  Twilight Lab wasn’t particularly interested in the Bright-side, of course—the Sun was Sanderson’s baby and he’d picked Mercury as the closest chunk of rock to the Sun that could hold his observatory. He’d chosen a good location, too. On Mercury, the Brightside temperature hits 770deg F at perihelion and the Darkside runs pretty constant at —410deg F. No permanent installation with a human crew could survive at either extreme. But with Mercury’s wobble, the twilight zone between Brightside and Darkside offers something closer to survival temperatures.

  Sanderson built the Lab up near the pole, where the zone is about five miles wide, so the temperature only varies 50 to 60 degrees with the libration. The Solar ‘scope could take that much change and they’d get good clear observation of the Sun for about seventy out of the eighty-eight days it takes the planet to wheel around.

  The Major was counting on Sanderson knowing something about Mercury as well as the Sun when we camped at the Lab to make final preparations.

  Sanderson did. He thought we’d lost our minds and he said so, but he gave us all the help he could. He spent a week briefing Jack Stone, the third member of our party, who had arrived with the supplies and equipment a few days earlier. Poor Jack met us at the rocket landing almost bawling, Sanderson had given him such a gloomy picture of what Brightside was like.

  Stone was a youngster—hardly twenty-five I’d say—but he’d been with the Major at Vulcan and had begged to join this trek. I had a funny feeling that Jack really didn’t care for exploring too much, but he thought Mikuta was God, and followed him around like a puppy.

  It didn’t matter to me as long as he knew what he was getting in for. You don’t go asking people in this game why they do it—they’re liable to get awfully uneasy and none of them can ever give you an answer that makes sense. Anyway, Stone had borrowed three men from the Lab, and had the supplies and equipment all lined up when we got there, ready to check and test.

  We dug right in. With plenty of funds—tri-V money and some government cash the Major had talked his way around—our equipment was new and good. Mikuta had done the designing and testing himself, with a big assist from Sanderson. We had four Bugs, three of them the light pillow-tire models, with special lead-cooled cut-in engines when the heat set in, and one heavy-duty tractor model for pulling the sledges.

  The Major went over them like a kid at the circus. Then he said, ‘Have you heard anything from McIvers?’

  ‘Who’s he?’ Stone wanted to know.

  ‘He’ll be joining us. He’s a good man—got quite a name for climbing, back home.’ The Major turned to me. ‘You’ve probably heard of him.’

  I’d heard plenty of stories about Ted Mclvers and I wasn’t too happy to hear that he was joining us. ‘Kind of a daredevil isn’t he?’

  ‘Maybe. He’s lucky and skillful. Where do you draw the line? We’ll need plenty of both.’

  ‘Have you ever worked with him?’ I asked.

  ‘No. Are you worried?’

  ‘Not exactly. But Brightside is no place to count on luck.’

  The Major laughed. ‘I don’t think we need to worry about Mclvers. We understood each other when I talked up the trip to him and we’re going to need each other too much to do any fooling around.’ He turned back to the supply list. ‘Meanwhile, let’s get this stuff listed and packed. We’ll need to cut weight sharply and our time is short. Sanderson says we should leave in three days.’

  Two days later, Mclvers hadn’t arrived. The Major didn’t say much about it. Stone was getting edgy and so was I. We spent the second day studying charts of the Brightside, such as they were. The best available were pretty poor, taken from so far out that the detail dissolved into blurs on blow-up. They showed the biggest ranges of peaks and craters and faults and that was all. Still, we could use them to plan a broad outline of our course.

  ‘This range here,’ the Major said as we crowded around the board, ‘is largely inactive, according to Sanderson. But these to the south and west could be active. Seismograph tracings suggest a lot of activity in that region, getting worse down toward the equator—not only volcanic, but sub-surface shifting.’

  Stone nodded. ‘Sanderson told me there was probably constant surface activity.’

  The Major shrugged. ‘Well, it’s treacherous, there’s no doubt of it. But the only way to avoid it is to travel over the Pole, which would lose us days and offer us no guarantee of less activity to the west. Now we might avoid some if we could find a pass through this range and cut sharp east—’

  It seemed that the more we considered the problem, the further we got from a solution. We knew there were active volcanoes on the Brightside—even on the Darkside, though surface activity there was pretty much slowed down and localized.

  But there were problems of atmosphere on Brightside, as well. There was an atmosphere and a constant atmospheric flow from Brightside to Darkside. Not much—the lighter gases had reached escape velocity and disappeared from Brightside millennia ago—but there was CO2, and nitrogen, and traces of other heavier gases. There was also an abundance of sulfur vapor, as well as carbon disulfide and sulfur dioxide.

  The atmospheric tide moved toward the Darkside, where it condensed, carrying enough volcanic ash with it for Sanderson to estimate the depth and nature of the surface upheavals on Brightside from his samplings. The trick was to find a passage that avoided those upheavals as far as possible. But in the final analysis, we were barely scraping the surface. The only way we would find out wha
t was happening where, was to be there.

  Finally, on the third day, McIvers blew in on a freight rocket from Venus. He’d missed the ship that the Major and I had taken by a few hours, and had conned his way to Venus in hopes of getting a hop from there. He didn’t seem too upset about it, as though this were his usual way of doing things and he couldn’t see why everyone should get so excited.

  He was a tall, rangy man with long, wavy hair prematurely gray, and the sort of eyes that looked like a climber’s—half-closed, sleepy, almost indolent, but capable of abrupt alertness.

  And he never stood still; he was always moving, always doing something with his hands, or talking, or pacing about.

  Evidently the Major decided not to press the issue of his arrival. There was still work to do, and an hour later we were running the final tests on the pressure suits. That evening, Stone and McIvers were thick as thieves, and everything was set for an early departure after we got some rest.

  ‘And that,’ said Baron, finishing his drink and signaling the waiter for another pair, ‘was your first big mistake.’

  Peter Clancy raised his eyebrows. ‘McIvers?’

  ‘Of course.’

  Clancy shrugged, glanced at the small quiet tables around them. “There are lots of bizarre personalities around a place like this, and some of the best wouldn’t seem to be the most reliable at first glance. Anyway, personality problems weren’t our big problem right then. Equipment worried us first and route next.’

  Baron nodded in agreement. ‘What kind of suits did you have?’

  ‘The best insulating suits ever made,’ said Clancy. ‘Each one had an inner lining of a fibreglass modification, to avoid the clumsiness of asbestos, and carried the refrigerating unit and oxygen storage which we recharged from the sledges every eight hours. Outer layer carried a monomolecular chrome reflecting surface that made us glitter like Christmas trees. And we had a half-inch dead-air space under positive pressure between the two layers. Warning thermocouples, of course—at 770 degrees, it wouldn’t take much time to fry us to cinders if the suits failed somewhere.’

  ‘How about the Bugs?’

  ‘They were insulated, too, but we weren’t counting on them too much for protection.’

  ‘You weren’t!’ Baron exclaimed. ‘Why not?’

  ‘We’d be in and out of them too much. They gave us mobility and storage, but we knew we’d have to do a lot of forward work on foot.’ Claney smiled bitterly. ‘Which meant that we had an inch of fibreglass and a half-inch of dead air between us and a surface temperature where lead flowed like water and zinc was almost at melting point and the pools of sulfur in the shadows were boiling like oatmeal over a campfire.’

  Baron licked his lips. His fingers stroked the cool, wet glass as he set it down on the tablecloth.

  ‘Go on,’ he said tautly. ‘You started on schedule?’

  ‘Oh, yes,’ said Clancy, ‘we started on schedule, all right. We just didn’t quite end on schedule, that was all. But I’m getting to that.’

  He settled back in his chair and continued.

  ==========

  We jumped off from Twilight on a course due southeast with thirty days to make it to the Center of Brightside. If we could cross an average of seventy miles a day, we could hit Center exactly at perihelion, the point of Mercury’s closest approach to the Sun—which made Center the hottest part of the planet at the hottest it ever gets.

  The Sun was already huge and yellow over the horizon when we started, twice the size it appears on Earth. Every day that Sun would grow bigger and whiter, and every day the surface would get hotter. But once we reached Center, the job was only half done—we would still have to travel another two thousand miles to the opposite twilight zone. Sanderson was to meet us on the other side in the Laboratory’s scout ship, approximately sixty days from the time we jumped off.

  That was the plan, in outline. It was up to us to cross those seventy miles a day, no matter how hot it became, no matter what terrain we had to cross. Detours would be dangerous and time-consuming. Delays could cost us our lives. We all knew that.

  The Major briefed us on details an hour before we left. ‘Peter, you’ll take the lead Bug, the small one we stripped down for you. Stone and I will flank you on either side, giving you a hundred-yard lead. McIvers, you’ll have the job of dragging the sledges, so we’ll have to direct your course pretty closely. Peter’s job is to pick the passage at any given point. If there’s any doubt of safe passage, we’ll all explore ahead on foot before we risk the Bugs. Got that?’

  Mclvers and Stone exchanged glances. Mclvers said: ‘Jack and I were planning to change around. We figured he could take the sledges. That would give me a little more mobility.’

  The Major looked up sharply at Stone. ‘Do you buy that, Jack?’

  Stone shrugged. ‘I don’t mind. Mac wanted—’

  Mclvers made an impatient gesture with his hands. ‘It doesn’t matter. I just feel better when I’m on the move. Does it make any difference?’

  ‘I guess it doesn’t,’ said the Major. ‘Then you’ll flank Peter along with me. Right?’

  ‘Sure, sure.’ Mclvers pulled at his lower lip. ‘Who’s going to do the advance scouting?’ ,

  ‘It sounds like I am,’ I cut in. ‘We want to keep the lead Bug light as possible.’

  Mikuta nodded. ‘That’s right. Peter’s Bug is stripped down to the frame and wheels.’

  Mclvers shook his head. ‘No, I mean the advance work. You need somebody out ahead—four or five miles, at least—to pick up the big flaws and active surface changes, don’t you?’ He stared at the Major. ‘I mean, how can we tell what sort of a hole we may be moving into, unless we have a scout up ahead?’

  ‘That’s what we have the charts for,’ the Major said sharply.

  ‘Charts! I’m talking about detail work. We don’t need to worry about the major topography. It’s the little faults you can’t see on the pictures that can kill us.’ He tossed the charts down excitedly. ‘Look, let me take a Bug out ahead and work reconnaissance, keep five, maybe ten miles ahead of the column. I can stay on good solid ground, of course, but scan the area closely and radio back to Peter where to avoid the flaws Then—’

  ‘No dice,’ the Major broke in.

  ‘But why not? We could save ourselves days!’

  ‘I don’t care what we could save. We stay together. When we get to the Center, I want live men along with me. That means we stay within easy sight of each other at all times. Any climber knows that everybody is safer in a party than one man alone—any time, any place.’

  Mclvers stared at him, his cheeks an angry red. Finally he gave a sullen nod. ‘Okay. If you say so.’

  ‘Well, I say so and I mean it. I don’t want any fancy stuff.

  We’re going to hit Center together and finish the Crossing together. Got that?’

  McIvers nodded. Mikuta then looked at Stone and me and we nodded, too.

  ‘All right,’ he said slowly. ‘Now that we’ve got it straight, let’s go.’

  It was hot. If I forget everything else about that trek, I’ll never forget that huge yellow Sun glaring down, without a break, hotter and hotter with every mile. We knew that the first few days would be the easiest and we were rested and fresh when we started down the long ragged gorge southeast of the Twilight Lab.

  I moved out first; back over my shoulder, I could see the Major and Mclvers crawling out behind me, their pillow tires taking the rugged floor of the gorge smoothly. Behind them, Stone dragged the sledges.

  Even at only 30 per cent Earth gravity they were a strain on the big tractor, until the ski-blades bit into the fluffy volcanic ash blanketing the valley. We even had a path to follow for the first twenty miles.

  I kept my eyes pasted to the big polaroid binocs, picking out the track the early research teams had made out into the edge of Brightside. But in a couple of hours we rumbled past Sanderson’s little outpost observatory and the tracks stopped. We were in virgin
territory and already the Sun was beginning to bite.

  We didn’t feel the heat so much those first days out. We saw it. The refrig units kept our skins at a nice comfortable seventy-five degrees Fahrenheit inside our suits, but our eyes watched that glaring Sun and the baked yellow rocks going past, and some nerve pathways got twisted up, somehow. We poured sweat as if we were in a superheated furnace.

  We drove eight hours and slept five. When a sleep period came due, we pulled the Bugs together into a square, threw up a light aluminium sun-shield and lay out in the dust and rocks. The sun-shield cut the temperature down sixty or seventy degrees, for whatever help that was. And then we ate from the forward sledge—sucking through tubes—protein, carbohydrates, bulk gelatin, vitamins.

  The Major measured water out with an iron hand, because we’d have drunk ourselves into nephritis in a week otherwise. We were constantly, unceasingly thirsty. Ask the physiologists and psychiatrists why—they can give you half a dozen interesting reasons—but all we knew, or cared about, was that it happened to be so.

  We didn’t sleep the first few stops, as a consequence. Our eyes burned in spite of the filters and we had roaring headaches, but we couldn’t sleep them off. We sat around looking at each other. Then McIvers would say how good a beer would taste, and off we’d go. We’d have murdered our grandmothers for one ice-cold bottle of beer.

  After a few driving periods, I began to get my bearings at the wheel. We were moving down into desolation that made Earth’s old Death Valley look like a Japanese rose garden. Huge sun-baked cracks opened up in the floor of the gorge, with black cliffs jutting up on either side; the air was filled with a barely visible yellowish mist of sulfur and sulfurous gases.

  It was a hot, barren hole, no place for any man to go, but the challenge was so powerful you could almost feel it. No one had ever crossed this land before and escaped. Those who had tried it had been cruelly punished, but the land was still there, so it had to be crossed. Not the easy way. It had to be crossed the hardest way possible: overland, through anything the land could throw up to us, at the most difficult time possible.