Building Harlequin’s Moon

by Larry Niven

  Harlequin’s moon system had become a dangerously cluttered region, but that wouldn’t last. When Erika finally warmed, she would find fewer moons, a system thinned out except for an inner ring that had been Moon Forty-one. Selene would be protected, to that extent, from giant meteoroid impacts.

  And Harlequin’s vast gaudy ring would be more than a match for Saturn’s. Gabriel’s gift to Erika! Playing God had its moments.

  “And why exactly are we doing this?” Wayne asked. He was shorter and stockier than Gabriel, and each of his movements was deliberate.

  Anger kept Gabriel from answering immediately. They were in the galley preparing an elaborate meal. Windows hovered in the air, showing several views of chaos. Rings and clouds of dust and inner storms, rainbows of light glaring through: chaos that would become Selene.

  It wasn’t pretty, but it was awesome. Wayne was one of the best engineers on the ship. He could fly anything, figure out any logistical problem. Surely Wayne shared his fierce pride?

  “Doing what?” Gabriel asked mildly. “We make Selene because we can.”

  “It’s like this. I went cold knowing that they’d warm me when we got to Ymir—to Henry Draper Catalog 212776,” Wayne said, being abnormally precise, no misunderstandings here, “and, and then we’d build Ymir. They thawed me out centuries early, at the wrong star! Now you tell me—”

  “They had to tell me first. Wayne, I was cold too. We’re the terraforming team, not ship’s crew. And ship’s crew were worn-out, man! The captain looked like the walking dead. Erika was twitchy. I wasn’t ready to throw it in their faces.”

  Wayne wasn’t being belligerent, he was plodding through a problem. “You tell me the interstellar drive went wonky and we had to find a refuge before the interstellar wind fried us all. Gamma rays at six percent of light-speed. We were lucky. Gliese 876 was almost in our path. We were down to the last whiffs of antimatter fuel when we made orbit here.

  “Now, I can buy all that. We can’t get to Ymir until we’ve made more fuel. Right. Why not just go for it? Build a collider and make twelve hundred kilos of antimatter and go.”

  “First off, you’ll notice that there’s no inner solar system.” Gabriel waved at the windows, though no such thing was obvious to the naked eye. “No asteroids, no rocky worlds like Earth or Mars, nothing until you get down to Daedalus, a mucking great gas giant world huddled right up against its sun. Daedalus ate everything as it moved inward. There’s only Harlequin, out here where Saturn would be if this were Sol system, and three more gas giants and the Kuiper Belt.

  “So all the distances out here are huge. Any resource we need has to come from Harlequin’s moons or the Kuiper Belt, where the little Kuiper Belt bodies are just as sparse as in Sol system. It takes forever to get anywhere.

  “We looked . . . the High Council looked at the problem,” Gabriel said carefully, “and the Astronaut program verifies. To build an antimatter generator, we need manpower. We’d have to warm half the ship. The garden wouldn’t feed them or recycle enough air, and we don’t have the room either. They’d use up all our resources. We’d die.

  “Second possibility is to build habitats like the asteroid civilizations in Sol system. What’s wrong with that?”

  Wayne snorted, though he knew he was being tested. “The Belt cities needed too much Artificial Intelligence, too much nanotech, too much of everything we’re running away from. AIs wound up running it all.”

  Gabriel nodded. “So we can’t do that. And we could build nanos and let them build a collider and run it for antimatter, with Astronaut running it all. Only we deliberately forgot most of what we need to build tailored nanotech, and Astronaut is another AI. By now it looks like Earth and Sol really have gone down the recycler, and if it wasn’t the AIs taking over, it must have been nanos turning everything to sludge. At any rate, Sol system isn’t talking.

  “So what’s left? We came here with gear to make Ymir habitable—a rocky world about the size of Earth, with a reducing atmosphere. We can make a world! It’s just a little bit tougher job.”

  Wayne said, “Sure. Where are you going to put the Beanstalk?”

  Gabriel finished his last bite of stew. He asked, “Your point?”

  “We stored this massive tether-making system. Ymir could have had two hundred thousand kilometers of an orbital tether standing up from the equator, all made of carbon nanotubes. Every bit of nanotechnology we permit ourselves is a compromise, and that was one of them. Ground to orbit transport. We’d have an elevator to the nearby planets. Go anywhere you want in Ymir’s inner system and only pay for the electricity. What would happen if—”

  “Selene would be whipping it around in Harlequin’s gravity field. The tides would tear it apart. We can’t give Selene a Beanstalk. What’s your point? Because I know we brought the wrong equipment for this!”

  “Exactly. We don’t know if it’s good enough,” Wayne said.

  “That’s the other side of it. Wayne, we’re making mistakes where it won’t matter. It’s a dry run. When we get to Ymir we’ll know more about our equipment and techniques.”

  “Won’t matter? Boss, what about all these people we’ll need to build the collider?”

  That was something Gabriel tried not to think about. He said, “I’m not on the High Council, you know.”

  Wayne sighed. “Okay, boss.”

  “Wayne, have you talked like this with Ali?”

  “No.”

  “Don’t.”

  Year 60,201, John Glenn shiptime

  When Gabriel warmed, there was only the AI to talk to. Humans were supposed to wake to human warmth, to hands and smiles and talk. But sixty thousand years was no time frame to thread a live person or set of people through, not when your population totaled only two thousand, and only a few hundred you wanted to warm at all before you could reach your true home. So John Glenn had orbited in silence, its huge garden mostly composted, its people frozen. The only aware beings were the AI, Astronaut, and periodically Gabriel; or on good shift breaks, Gabriel and Wayne; or on better ones, Gabriel and Ali.

  This was a good break. He’d wake, and then he’d warm Ali, and then . . . then they’d touch down on Selene. He glanced at the chronometer. He was waking on schedule. So nothing horrible had happened during this sleep. His senses rushed alert, smelling medicines and water, feeling the dry cool ship’s air. What Earth had sent them—new programming for nanotechnological cell repair under cold sleep—still acted perfectly.

  Gabriel wasn’t sure how he felt about that. Nanotechnology was one of the things they had run away from.

  It almost never got said.

  There would come a day when Ymir was perfected. On that day all this nonsense of medical nanotech would stop. The long-lived travelers would age naturally, and die naturally. Their planet would follow its own destiny, and none would use his power to change the weather or stop an encroaching desert. They’d made that agreement, all of them, before they boarded the carrier ships.

  They’d wondered about each other since, and they’d wondered about themselves. How could they not? Which of them would fail to give up longevity and the power to shape a world?

  “Astronaut?”

  “Hello, Gabriel!”

  “Any word from Earth?” Gabriel already knew the answer.

  “Not since Year 291, shiptime.”

  “From Ymir?”

  “Nothing, Gabriel.”

  It might be that Gabriel was the only human heartbeat in the entire universe.

  He flinched from that thought. Surely there were humans at Ymir. Surely Leif Eriksson and Lewis and Clark had reached Ymir, safe, and thousands or millions of humans now populated a rebuilt planet. Or billions? Ymir was to have been made a second Earth, and Earth had housed tens of billions, sixty thousand years ago. They’d sent message probes, traveling at a tenth light-speed at best, at the highpoint of their journey. A hundred forty-eight light-years distanced them, at Gliese 876, from Ymir at HDC 212776. That was a lot
of distance for fragile probes to travel.

  Gabriel wiggled his toes, stretched his fingers, and bounced his calves lightly on the bed.

  Two hours later, he pushed himself to standing and went to the galley to make tea infused with vitamins and mint, easy for a rejuvenated and rebuilt body to accept. He took the tea to his office, wrinkling his nose at the medicinal smell, and ordered Astronaut to pull up views of Selene.

  Bad smelling or not, the first sip of tea sat warm and perfect in his belly as images of the little moon filled his walls.

  A cloud obscured part of the surface. A cloud! He smiled broadly, then laughed in delight. He sat mesmerized, watching the cloud, until his tea bulb was empty.

  Then he started barking out a list for Astronaut to read to him: precipitation measures, exact atmospheric composition, water loss, evaporation . . .

  Within an hour, Gabriel confirmed they could walk on the moon. They could start to introduce life. They could . . . he gave instructions to wake Ali and Wayne, and went to get ready for them. He sang as he pulled himself down the corridor to Medical.

  GABRIEL AND ALI WALKED on the barren surface of the little moon. They started inside light pressure suits, taking readings and checking radiation levels, double-testing what they already knew from the tiny sensors that dotted Selene. Ali stripped first, all the way down to underwear and bra and shoes, oxygen tank and mask. Her olive skin dimpled in the cool air.

  He laughed with pleasure watching her; a tiny half-naked woman climbing on rocks; jumping from one to the other, tossing stones and catching them.

  Drawn by Ali’s antics, Gabriel stripped to his pants and shirt, mask and tank, and ran and cavorted and grinned while Ali knelt and touched the regolith, walked to a new place, and touched the surface again. He danced with her on the surface, seeing wonder and reverence in her eyes as she moved easily, gracefully.

  Selene was still a touch unstable; it shivered twice with small quakes in the hours they were there. Ali came and stood beside him. “I like the silence—I like being away from that damned constant data flow. It feels more human here.”

  Gabriel held her, not answering, just feeling the soft touch of her dark head in the hollow of his shoulder. He felt lost without the data, regardless of how ecstatic he was to be on Selene. On Selene!

  “Someday,” he said, “Selene will be information rich like the ship. We’ll enhance the flows some here before we return—I’ll need it to monitor the next steps.”

  She glared at him, a touch distant suddenly. “Be careful—you’ll need too much technology. Let’s keep Selene simple.”

  Her face was bathed in Apollo’s light, her skin duskier than he remembered from the ship. They pulled their masks aside, and he gave her the first kiss on Selene. It was quick. Selene had just barely more oxygen, right now, than the top of Everest. It needed life to make a living atmosphere.

  Thousands of years of shifts had taught them all to take intimacy where they found it, to appreciate it, and consider it friendship.

  They flew happily back up to John Glenn. Gabriel returned with Wayne, and while Gabriel and Wayne walked Selene’s surface, Ali packed up cultures and genetic material so they could start seeding the regolith, eventually covering part of Selene with bacteria to begin the process of making soil.

  When they warmed next, all of the bacteria were dead. So they stayed awake and watched the next attempt, killing time designing a huge tent. They would control the atmosphere inside the tent, and use it to build greenhouses and homes; a little city. The tent stood up well to the little earthquakes that came along. They dubbed the new town Aldrin, and stayed there from time to time.

  It took four tries—twenty years—to get healthy cyanobacteria mats spread across the ground near Aldrin and have something like soil. Now it was time to wake the High Council.

  Gabriel spent hours with each of them, running low on sleep, talking excitedly. He had Astronaut play videos for the captain; lost moons dancing into each other. Gabriel watched the captain’s wrinkled face closely, saw how his deep-ocean-blue eyes tracked the flow of moons and proto-comets.

  Captain John Hunter had stayed awake during the long crippled flight that took them to Gliese 876 after they nearly burned up in the interstellar wind. That trip was so long that no amount of post-ice rejuvenation treatments had removed the spots and lines and dark circles that transformed his face. Centuries of pain were etched in odd bends of his fingers and toes, in the hunch in his back, the folds over his eyes. But intelligence still lived in his eyes. If anything, the ravages his choices had created in his body made his will stronger. It mattered to Gabriel that John Hunter see the dream he’d helped design come alive.

  It went well, except for the astonishing rapidity with which Council returned to the cryo-tanks. They wanted an easier world to oversee.

  Once, Gabriel warmed Erika. By then, Wayne was building roads, using huge robotic machines to flatten the soil. Ali was cold. Gabriel was designing pipes to control the hydrology, and constructing a small factory by the Hammered Sea. Erika stayed warm for a year, giving Gabriel good advice, making a few mistakes they laughed at together, fretting about how long everything took. The plan was already foreshortened—Gabriel would never have forced so many processes if Selene wasn’t really just a way to escape to the stars again.

  He held Erika’s attention for a year before she insisted on going cold again.

  Gabriel and Ali finished the little town of Aldrin. They laid pipes to carry water to a cistern, more pipes to make a rudimentary sewer and reclamation system, planted a grove of trees on a hill outside town, and filled greenhouses with seedlings. The night before they planned to wake High Council again, Gabriel and Ali made love, alone on the surface of the moon they’d transformed. Their love-making started soft and slow, growing to a deep intimate conclusion. They stayed still for a long time, wrapped in each other’s arms, warm in that close place that follows on the heels of lovemaking. When she stopped trembling, Ali looked at Gabriel and said, “We’ve consecrated the ground here. Selene has been blessed. We blessed it together.”

  Gabriel simply thought they’d enjoyed great sex, but it was a celebration, and so he didn’t contradict her. Rather, he held her tightly and began to work out hydrologic engineering problems in his head.

  PART I: SELENE

  60, 268 John Glenn shiptime

  CHAPTER 1

  TEACHING GROVE

  RACHEL REACHED FOR the seedling. Her long fingers found the pliant trunk, thin as her pinkie, buried inside the furled branches. She unwrapped gauzy material from the root ball with her free hand, separating the roots by spreading them down and out in the air. Bits of soil fell through her hands as she settled roots and tree onto a mound of nutrient-enriched dirt. Still steadying the gangly cecropia, she swept anchor soil to cover the roots, tamped it down, and then tied the trunk very loosely to a long thin stake. Rachel sat back on her heels and admired the little tree. A warm breeze rustled its leaves and the smell of damp dirt filled the air.

  A banana palm went in next, then a set of three heliconias near the path. Rachel’s crate stood empty. The distant sun, Apollo, hung low in the sky, illuminating beads of sweat as she stretched.

  The other students had all finished more than twenty minutes ago. Rachel nodded to herself, checking to be sure the plot matched the picture in her head. Harry’s plot was well designed, and cleaner since he had gone back and raked the soil after watering. But she could do that too. Water first. She sighed and got up to get a rake.

  “Nice job.” Gabriel’s voice behind her sounded flat, far away, even if the words approved.

  Rachel turned around and looked back at him. Gabriel stood an inch taller than Rachel, but wider and stronger, carefully dressed in brown pants that tied at the ankles, high boots, and a tight-fitting shirt that showed muscles. He looked serious, like he’d gotten lost in his head. She wrinkled her nose at him and smiled. He didn’t smile back. He looked outward, higher than the horizon,
fingering the bright metal and bead sculptures twisted into the long red-brown braid of his hair.

  Rachel ran her fingers through her own short red hair, wondering if such a long braid was heavy. And what was he looking at?

  Diamond patterns in a thousand shades of white and red: a gibbous world, huge and fully risen, brilliant across more than half its arc, sullen red where the sunlight didn’t fall. Harlequin. A broad straight band ran blazing white across its face, and disappeared where Harlequin’s shadow fell across it. A ring, Gabriel called it, but nothing ever showed but that thick white slash.

  What fascinated Gabriel about Harlequin and its ring? It was a feature of the sky, changeable, but not of great interest. Tiny fiery-looking storms on Harlequin might affect weather on Selene, Gabriel had said once, but (he admitted) not by much.

  A mystery. Council was always a mystery. Rachel knew Gabriel would wait there until she finished. Another mystery—Council always knew where they were—they could see everything on Selene. So he didn’t have to stay. Maybe I shouldn’t rake since I’m last, she thought. But the test is tomorrow!

  She watered and raked anyway, perversely determined to spend time with each tree as she finished for the evening. Perfect, it might please Gabriel. (He still hadn’t moved.)

  She put the rake away and stood as near Gabriel as she dared, and looked up too. Harlequin rose as Apollo rode low in the sky and then disappeared. Softer illumination replaced the red-gold sunlight, tinged by the oranges and reds of the gas giant. The planet covered a huge portion of the sky. Rachel could cover Apollo, the distant sun, with the width of her thumb held half an arm’s length in front of her. Harlequin took both palms to blot from view.

  The gas giant made its own dim red light, shed by the intense heat in its constantly churning surface. Apollo’s reflection brightened Harlequin’s inner light, and the combined glow bathed Selene’s summer, making the night barely dusky.