Alan Edward Nourse

“ 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. ”

“ 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.”
McIvers stared at him, his cheeks an angry red. ”

“ 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. ”

“ The only worse heat in the Solar System was the surface of the Sun itself.
Brightside was worth trying for. We would get it or it would get us. That was the bargain.
I learned a lot about Mercury those first few driving periods. The gorge petered out after a hundred miles and we moved onto the slope of a range of ragged craters that ran south and east. This range had shown no activity since the first landing on Mercury forty years before, but beyond it there were active cones. Yellow fumes rose from the craters constantly; their sides were shrouded with heavy ash. ”

“ Twilight Lab wasn’t particularly interested in the Brightside, 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 770° F. at perihelion and the Darkside runs pretty constant at -410° 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. ”

“ The Major shot me a glance, then turned to Stone. “Get a cable from the second sledge fast. He’ll fry alive if we don’t get him out of there. Peter, I need you to lower me. Use the tractor winch.”
I lowered him; he stayed down only a few moments. When I hauled him up, his face was drawn. “Still alive,” he panted. “He won’t be very long, though.” He hesitated for just an instant. “We’ve got to make a try.”
“I don’t like this ledge,” I said. “It’s moved twice since I got out. Why not back off and lower him a cable?”
“No good. The Bug is smashed and he’s inside it. ”

“ Too many men in this game are all nerve and luck, with no judgment. The Major had both. He also had the kind of personality that could take a crew of wild men and make them work like a well-oiled machine across a thousand miles of Venus jungle. ”

“ 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 fiberglass 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?” ”

“ But Brightside is no place to count on luck.”
The Major laughed. “I don’t think we need to worry about McIvers. 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.” ”

“ Then he geared his Bug on around to my flank again.
At the stopover, the incident wasn’t mentioned again, but the Major drew me aside just as I was settling down for sleep. “Peter, I’m worried,” he said slowly.
“McIvers? Don’t worry. He’s not as reckless as he seems—just impatient. We are over a hundred miles behind schedule and we’re moving awfully slow. We only made forty miles this last drive.” ”

“ 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. ”

“ 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 what was happening where was to be there.
Finally, on the third day, McIvers blew in on a freight rocket from Venus. ”

“ We had to keep to our schedule even if it killed us, because it would positively kill us if we didn’t.”
“But a man like that—”
“A man like McIvers was necessary. Can’t you see that? It was the Sun that beat us, that surface. Perhaps we were licked the very day we started.” Claney leaned across the table, his eyes pleading. “We didn’t realize that, but it was true. There are places that men can’t go, conditions men can’t tolerate. The others had to die to learn that. I was lucky, I came back. But I’m trying to tell you what I found out—that nobody will ever make a Brightside Crossing.” ”

“ 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. ”