"I'm sorry," Lang said quietly. "Go on with what you were saying."

"Well," Song admitted, "it wasn't a bad inference, at that. But the holes I saw were not punched through. They were eaten away." She waited for Lang to protest that the dome bottom was about as chemically inert as any plastic yet devised. But Lang had learned her lesson. And she had a talent for facing facts.

"So. We have a thing here that eats plastic. And seems to be made of plastic, into the bargain. Any ideas why it picked this particular spot to grow, and no other?"

"I have an idea on that," McKillian said. 'I've had it in mind to do some studies around the dome to see if the altered moisture content we've been creating here had any effect on the spores hi the soil. See, we've been here nine days, spouting out water vapor, carbon dioxide, and quite a bit of oxygen into the atmosphere. Not much, but maybe more than it seems, considering the low concentrations that are naturally available. We've altered the biome. Does anyone know where the exhaust air from the dome was expelled?"

Lang raised her eyebrows. "Yes, it was under the dome. The air we exhausted was warm, you see, and it was thought it could be put to use one last time before we let it go, to warm the floor of the dome and decrease heat loss.""And the water vapor collected on the underside of the dome when it hit the cold air. Right, Do you get the picture?"

"I think so," Lang said. "It was so little water, though. You know we didn't want to waste it; we condensed it out until the air we exhausted was dry as a bone."

"For Earth, maybe. Here it was a torrential rainfall. It reached seeds or spores in the ground and triggered them to start growing. We're going to have to watch it when we use anything containing plastic.

What does that include?"

Lang groaned. "All the air-lock seals, for one thing." There were grimaces from all of them at the thought of that. "For another, a good part of our suits. Song, watch it, don't step on that thing. We don't know bow powerful it is or if it'll eat the-plastic in your boots, but we'd better play it safe. How about it, Ralston? Think you can find out how bad it is?"

"You mean identify the solvent these things use? Probably, if we can get some sort of work s.p.a.ce and I can get to my equipment."

"Mary," McKillian said, "it occurs to me that I'd better start looking for airborne spores. If there are some, it could mean that the airlock on the Podkayne is vulnerable. Even thirty meters off the ground."

"Right. Get on that. Since we're sleeping in it until we can find out what we can do on the ground, we'd best be sure it's safe. Meantime, well all sleep in our suits." There were helpless groans at this, but no protests. McKillian and Ralston headed for the pile of salvaged equipment, hoping to rescue enough to get started on their a.n.a.lyses. Song knelt again and started digging around one of the ten-centimeter spikes.

Crawford followed Lang back toward the Podkayne.

"Mary, I wanted. . . is it all right if I call you Mary?"

"I guess so. I don't think 'Commander Long' would wear well over five years. But you'd better still think commander."

He considered it. "All right, Commander Mary." She punched him playfully. She had barely known him before the disaster. He had been a name on a roster and a sore spot in the estimation of the Astronaut Corps. But she had borne him no personal malice, and now found herself beginning to like him.

"What's on your mind?"

"Ah, several things. But maybe it isn't my place to bring them up now. First, I want to say that if you're ... ah, concerned, or doubtful of my support or loyalty because I took over command for a while. .

. earlier today, well. . ."

"Well?"

"I just wanted to tell you that I have no ambitions in that direction," he finished lamely.

She patted him on the back. "Sure, I know. You forget, I read your dossier. It mentioned several interesting episodes that I'd like you to tell me about someday, from your 'soldier-of-fortune' days-"

"h.e.l.l, those were grossly overblown. I just happened to get into some sc.r.a.pes and managed to get out of them."

"Still, it got you picked for this mission out of hundreds of applicants. The thinking was that you'd be a wild card, a man of action with proven survivability. Maybe it worked out. But the other thing I remember on your card was that you're not a leader. No, that you're a loner who'll cooperate with a group and be no discipline problem, but you work better alone. Want to strike out on your own?"

He smiled at her. "No, thanks. But what you said is right I have no hankering to take charge of anything. But I do have some knowledge that might prove useful."

"And well use it. You just speak up, I'll be listening." She started to say something, then thought of something else. "Say, what are your ideas on a woman bossing this project? I've had to fight that all the way from my Air Force days. So if you have any objections you might as well tell me up front"

He was genuinely surprised. "You didn't take that crack seriously, did you? I might as well admit it. It was intentional, like that cattle prod you mentioned. You looked like you needed a kick in the a.s.s."

"And thank you. But you didn't answer my question."

"Those who lead, lead," he said, simply. "I'll follow you as long as you keep leading,"

"As long as it's in the direction you want?" She laughed, and poked him in the ribs. "I see you as myGrand Vizier, the man who holds the arcane knowledge and advises the regent. I think I'll have to watch out for you. I know a little history, myself."

Crawford couldn't tell how serious she was. He shrugged it off.

"What I really wanted to talk to you about is this: You said you couldn't fly this ship. But you were not yourself, you were depressed and feeling hopeless. Does that still stand?"

"It stands. Come on up and I'll show you why."

In the pilot's cabin, Crawford was ready to believe her. Like all flying machines since the days of the windsock and open c.o.c.kpit, this one was a mad confusion of dials, switches, and lights designed to awe anyone who knew nothing about it. He sat in the copilot's chair and listened to her.

"We had a back-up pilot, of course. You may be surprised to learn that it wasn't me. It was Dorothy Cantrell, and she's dead. Now I know what everything does on this board, and I can cope with most of it easily. What I don't know, I could learn. Some of the systems are computer-driven; give it the right program and it'll fly itself, hi s.p.a.ce." She looked longingly at the controls, and Crawford realized that, like Weinstein, she didn't relish giving up the fun of flying to boss a gang of explorers. She was a former test pilot, and above all things she loved flying. She patted an array of hand controls on her right side. There were more like them on the left.

"This is what would kill us, Crawford. What's your first name? Matt. Matt, this baby is a flyer for the first forty thousand meters. It doesn't have the juice to orbit on the jets alone. The wings are folded up now. You probably didn't see them on the way in, but you saw the models. They're very light, supercritical, and designed for this atmosphere. Lou said it was like flying a bathtub, but it flew. And it's a skill, almost an art. Lou practiced for three years on the best simulators we could build and still had to rely on things you can't learn in a simulator. And he barely got us down in one piece. We didn't noise it around, but it was a d.a.m.n close thing. Lou was young; so was Cantrell. They were both fresh from flying.

They flew every day, they had the feel for it. They were tops." She slumped back into her chair. "I haven't flown anything but trainers for eight years."

Crawford didn't know if he should let it drop.

"But you were one of the best, everyone knows that. You still don't think you could do it?"

She threw up her hands. "How can I make you understand? This is nothing like anything I've ever flown. You might as well. . ." She groped for a comparison, trying to coax it out with gestures in the air.

"Listen. Does the fact that someone can fly a biplane, maybe even be the best G.o.dd.a.m.n biplane pilot that ever was, does that mean they're qualified to fly a helicopter?"

"I don't know."

"It doesn't. Believe me."

"All right. But the fact remains that you're the closest thing on Mars to a pilot for the Podkayne. I think you should consider that when you're deciding what we should do." He shut up, afraid to sound like he was pushing her.

She narrowed her eyes and gazed at nothing.

"I have thought about it." She waited for a long time. "I think the chances are about a thousand to one against us if I try to fly it. But I'll do it, if we come to that. And that's your job. Showing me some better odds. If you can't, let me know."

Three weeks later, the Tharsis Canyon had been transformed into a child's garden of toys. Crawford had thought of no better way to describe it. Each of the plastic spikes had blossomed into a fanciful windmill, no two of them just alike. There were tiny ones, with the vanes parallel to the ground and no more than ten centimeters tall. There were derricks of spidery plastic struts that would not have looked too out of place on a Kansas farm. Some of them were five meters high. They came in all colors and many configurations, but all had vanes covered with a transparent film like cellophane, and all were spinning into colorful blurs in the stiff Martian breeze. Crawford thought of an industrial park built by gnomes. He could almost see them trudging through the spinning wheels.

Song had taken one apart as well as she could. She was still shaking her head in disbelief. She had not been able to excavate the long insulated taproot, but she could infer how deep it went. It extended all the way down to the layer of permafrost, twenty meters down.The ground between the windmills was coated in shimmering plastic. This was the second part of the plants' ingenious solution to survival on Mars. The windmills utilized the energy in the wind, and the plastic coating on the ground was in reality two thin sheets of plastic with a s.p.a.ce between for water to circulate.

The water was heated by the sun then pumped down to the permafrost, melting a little more of it each time.

"There's still something missing from our picture," Song had told them the night before, when she delivered her summary of what she had learned. "Marry hasn't been able to find a mechanism that would permit these things to grow by ingesting sand and rock and turning it into plastic-like materials. So we a.s.sume there is a reservoir of something like crude oil down there, maybe frozen in with the water."

"Where would that have come from?" Lang had asked.

"You've heard of the long-period Martian seasonal theories? Well, part of it is more than a theory.

The combination of the Martian polar inclination, the precessional cycle, and the eccentricity of the orbit produces seasons that are about twelve thousand years long. We're in the middle of winter, though we landed in the nominal 'summer/ It's been theorized that if there were any Martian life it would have adapted to these longer cycles. It hibernates in spores during the cold cycle, when the water and carbon dioxide freeze out at the poles, then comes out when enough ice melts to permit biological processes. We seem to have fooled these plants; they thought summer was here when the water vapor content went up around the camp."

"So what about the crude?" Ralston asked. He didn't completely believe that part of the model they had evolved. He was a laboratory chemist, specializing in inorganic compounds. The way these plants produced plastics without high heat, through purely catalytic interactions, had him confused and defensive. He wished the crazy windmills would go away.

"I think I can answer that," McKillian said. "These organisms barely sc.r.a.pe by in the best of times.

The ones that have made it waste nothing. It stands to reason that any really ancient deposits of crude oil would have been exhausted in only a few of these cycles. So it must be that what we're thinking of as crude oil must be something a little different It has to be the remains of the last generation."

"But how did the remains get so far below ground?" Ralston asked. "You'd expect them to be high up. The winds couldn't bury them that deep in only twelve thousand years."

"You're right," said McKillian. "I don't really know. But I have a theory. Since these plants waste nothing, why not conserve then" bodies when they die? They sprouted from the ground; isn't it possible they could withdraw when things start to get tough again? They'd leave spores behind them as they retreated, distributing them all through the soil. That way, if the upper ones blew away or were sterilized by the ultraviolet, the ones just below them would still thrive when the right conditions returned. When they reached the permafrost, they'd decompose into this organic slush we've postulated, and. . . well, it does get a little involved, doesn't it?"

"Sounds all right to me," Lang a.s.sured her. "It'll do for a working theory. Now what about airborne spores?"

It turned out that they were safe from that imagined danger. There were spores in the air now, but they were not dangerous to the colonists. The plants attacked only certain kinds of plastics, and then only in certain stages of their lives. Since they were still changing, it bore watching, but the airlocks and suits were secure. The crew was enjoying the luxury of sleeping without their suits.

And there was much work to do. Most of the physical sort devolved on Crawford and, to some extent, on Lang. It threw them together a lot. The other three had to be free to pursue their researches, as it had been decided that only in knowing their environment would they stand a chance.

The two of them had managed to salvage most of the dome. Working with patching kits and lasers to cut the tough material, they had constructed a much smaller dome. They erected it on an outcropping of bare rock, rearranged the exhaust to prevent more condensation on the underside, and added more safety features. They now slept in a pressurized building inside the dome, and one of them stayed awake on watch at all times. In drills, they had come from a deep sleep to full pressure-integrity in thirty seconds. They were not going to get caught again.

Crawford looked away from the madly whirling rotors of the windmill farm. He was with the rest ofthe crew, sitting in the dome with his helmet off. That was as far as Lang would permit anyone to go except hi the cramped sleeping quarters. Song Sue Lee was at the radio giving her report to the Edgar Rice Burroughs. In her hand was one of the pump modules she had dissected out of one of the plants. It consisted of a half-meter set of eight blades that turned freely on teflon bearings. Below it were various tiny gears and the pump itself. She twirled it idly as she spoke.

"I don't really get it," Crawford admitted, talking quietly to Lucy McKillian. "What's so revolutionary about little windmills?"

"It's just a whole new area," McKillian whispered back. "Think about it Back on Earth, nature never got around to inventing the wheel. I've sometimes wondered why not There are limitations, of course, but it's such a good idea. Just look what we've done with it But all motion hi nature is confined to up and down, back and forth, in and out, or squeeze and relax. Nothing on Earth goes round and round, unless we built it. Think about it"

Crawford did, and began to see the novelty of it. He tried hi vain to think of some mechanism hi an animal or plant of Earthly origin that turned and kept on turning forever. He could not Song finished her report and handed the mike to Lang. Before she could start, Weinstein came on the line.

"We've had a change in plan up here," he said, with no preface. "I hope this doesn't come as a shock.

If you think about it, you'll s the logic hi it We're going back to Earth in seven days."

It didn't surprise them too much. The Burroughs had given then: just about everything it could hi the form of data and supplies. There was one more capsule load due; after that, its presence would only be a frustration to both groups. There was a great deal of irony hi having two such powerful ships so close to each other and being so helpless to do anything concrete. It was telling on the crew of the Burroughs.

"We've recalculated everything based on the lower ma.s.s without the twenty of you and the six tons of samples we were allowing for. By using the fuel we would have ferried down to you for takeoff, we can make a faster orbit down toward Venus. The departure date for that orbit is seven days away. We'll rendezvous with a drone capsule full of supplies we hadn't counted on." And besides, Lang thought to herself, it's much more dramatic. Plunging sunward on the chancy cometary orbit, their pantries stripped bare, heading for the fateful rendezvous . . .

"I'd like your comments," he went on. "This isn't absolutely final as yet."

They all looked at Lang. They were rea.s.sured to find her calm and unshaken.

"I think it's the best idea. One thing: you've given up on any thoughts of me flying the Podkayne?"

"No insult intended, Mary," Weinstein said gently. "But, yes, we have. It's the opinion of the people Earthside that you couldn't do it. They've tried some experiments, coaching some very good pilots and putting them into the simulators. They can't do it, and we don't think you could, either."

"No need to sugar-coat it I know it as well as anyone. But even a billion to one shot is better than nothing. I take it they think Crawford is right, that survival is at least theoretically possible?"

There was a long hesitation. "I guess that's correct. Mary, I'll be frank. I don't think it's possible. I hope I'm wrong, but I don't expect ..."

"Thank you, Winey, for the encouraging words. You always did know what it takes to buck a person up. By the way, that other mission, the one where you were going to ride a meteorite down here to save our a.s.ses, that's scrubbed, too?"

The a.s.sembled crew smiled, and Song gave a high-pitched cheer. Weinstein was not the most popular man on Mars.

"Mary, I told you about that already," he complained. It was a gentle complaint and, even more significant he had not objected to the use of his nickname. He was being gentle with the condemned. "We worked on it around the clock. I even managed to get permission to turn over command temporarily. But the mock-ups they made Earthside didn't survive the re-entry. It was the best we could do. I couldn't risk the entire mission on a configuration the people back on Earth wouldn't certify."

"I know. I'll call you back tomorrow." She switched the set off and sat back on her heels. "I swear, if the Earthside tests on a roll of toilet paper didn't ... he wouldn't. . ." She cut the air with her hands. "What am I saying? That's petty. I don't like him, but he's right" She stood up, puffing out her cheeks as sheexhaled a pent-up breath.

"Come on, crew, we've got a lot of work."

They named their colony New Amsterdam, because of the windmills. The name of whirligig was the one that stuck on the Martian plants, though Crawford held out for a long time in favor of spinnakers.

They worked all day and tried their best to ignore the Burroughs overhead. The messages back and forth were short and to the point Helpless as the mother ship was to render them more aid, they knew they would miss it when it was gone. So the day of departure was a stiff, determinedly nonchalant affair.

They all made a big show of going to bed hours before the scheduled breakaway.

When he was sure the others were asleep, Crawford opened his eyes and looked around the darkened barracks. It wasn't much in the way of a home; they were crowded against each other on rough pads made of insulating material. The toilet facilities were behind a flimsy barrier against one wall, and smelled. But none of them would have wanted to sleep outside in the dome, even if Lang had allowed it.

The only light came from the illuminated dials that the guard was supposed to watch all night There was no one sitting in front of them. Crawford a.s.sumed the guard had gone to sleep. He would have been upset, but there was no time. He had to suit up, and he welcomed the chance to sneak out He began to furtively don his pressure suit.

As a historian, he felt he could not let such a moment slip by un.o.bserved. Silly, but there it was. He had to be out there, watch it with his own eyes. It didn't matter if he never lived to tell about it, he must record it.

Someone sat up beside him. He froze, but it was too late. She rubbed her eyes and peered into the darkness.

"Matt?" she yawned. "What's. . . what is it? Is something-"

"Shh. I'm going out. Go back to sleep. Song?"

"Um hmmm." She stretched, dug her knuckles fiercely into her eyes, and smoothed her hair back from her face. She was dressed in a loose-fitting bottoms of a ship suit, a gray piece of dirty cloth that badly needed washing, as did all their clothes. For a moment, as he watched her shadow stretch and stand up, be wasn't interested in the Burroughs. He forced his mind away from her.

"I'm going with you," she whispered.

"All right. Don't wake the others."

Standing just outside the airlock was Mary Lang. She turned as they came out, and did not seem surprised.

"Were you the one on duty?" Crawford asked her.

"Yeah. I broke my own rule. But so did you two. Consider yourselves on report." She laughed and beckoned them over to her. They linked arms and stood staring up at the sky.

"How much longer?" Song asked, after some time had pa.s.sed.

"Just a few minutes. Hold tight." Crawford looked over to Lang and thought he saw tears, but he couldn't be sure in the dark.

There was a tiny new star, brighter than all the rest, brighter than Phobos. It hurt to took at it but none of them looked away. It was the fusion drive of the Edgar Rice Burroughs, heading sunward, away from the long winter on Mars. It stayed on for long minutes, then sputtered and was lost. Though it was warm in the dome, Crawford was shivering. It was ten minutes before any of them felt like facing the barracks.

They crowded into the airlock, carefully not looking at each other's faces as they waited for the automatic machinery. The inner door opened and Lang pushed forward-and right back into the airlock.