Malenfant reached up and took off his helmet. He shook his head, and little spherical balls of sweat drifted away from his forehead, swimming in straight lines through the air. “All my life I dreamed of this.” The helmet, released, floated above his belly, drifting in some random air current. He knocked it with a finger, and it started to spin.

Emma found her gaze following the languid rotation of the helmet. Suddenly it felt as if the helmet was stationary and it was the rest of the ship that was rotating, and her head was a balloon full of water through which waves were passing. She closed her eyes and pressed her head back against the headrest of her couch until the spinning sensation stopped.

There was a sound like a cough, a sharp stink of bile.

Emma opened her eyes and tried to lift her head, but her vision swam again. “Michael?”

“No,” Cornelius said, his voice tight. And now she saw a big ball of vomit, green laced with orange, shimmering up into the air above them. Complex waves crossed its surface, and it seemed to have ten or a dozen smaller companions traveling with it.

“Oh, Christ, Cornelius,” Malenfant said. He reached under his couch and pulled out a plastic bag that he swept around the vomit ball. When the vomit touched the surface of the bag, it started to behave “normally”; it spread out all over the interior of the bag in a sticky, lumpy mess.

It was like nothing Emma had seen before; she lay there and watched the little drama unfold, mindless of the stink.

There was a new series of low bangs, like guns firing, from beyond the wall beside Emma. With each bang she felt a wrench as her couch dragged her sideways.

“Take it easy,” Malenfant said to them all. “That’s just the hy-drazine attitude thrusters firing, spinning us up. We’re feeling transients. They’ll dampen out.”

There were metallic groans from the hull, pops and snaps from the latches that docked the Earth-entry module to the rest of the spacecraft cluster. It was like being in a huge, clumsy fairground ride.

But at length, as the spin built up, she felt a return of weight, a gentle push that made her sink back into her seat once more.

The attitude thrusters cut out.

“Right on the button,” Malenfant said. “We is pinwheeling to the stars, people. Let’s go open up the shop.”

He released his restraints. He stood up in his couch, his feet bouncing above the fabric, and he pulled at levers and straps until a central section of the instrument panel above him folded back. It was like rearranging the interior of a station wagon. Beyond the panel was a short tunnel leading to a hatch like a submarine’s — a heavy iron disc with a wheel at the center.

Malenfant said, “One, two, three.” He took a jump into the air. He drifted upward easily, floated sideways and gently impacted the wall of the tunnel. He grabbed on to a rung, his boots dangling. “Coriolis force,” he said. “Piece of cake.” He pulled himself farther into the tunnel, then reached up and hauled at the wheel.

But the wheel was jammed, presumably by the vibration of launch. What an anticlimax, Emma thought. Malenfant had to have Emma pass up a big wrench, and he used this to hit the wheel until it came loose. At last Malenfant had the wheel turning, and he pushed the hatch upward and out of the way. He floated easily through the hatch, his booted feet trailing after him. Emma, looking up beyond him, saw a disc of gray fluorescent light.

She glanced at Cornelius. “Me next?”

Cornelius’ face, still inside his helmet, was actually green. “I’ll pass Michael up.”

She took offher own helmet and stowed it carefully on Malen-fant’s vacated couch. Then, breathing hard, she undipped her restraints and laid them aside. She pushed down at her chair, cautiously. She drifted into the air a little way, fell back slowly. It was like wading through a waist-deep swimming pool.

She was aware of Michael watching her, his eyes round and bright inside his helmet.

She tried to think of something to say to him. But of all of them he seemed the most centered, she sensed, the most at home in this starkly new environment. How strange that was.

Without giving herself time to think about it, she bent her knees and pushed up.

She had leapt like an Olympic athlete, but she drifted away from her course and slammed, harder than Malenfant, against the wall of the tunnel. But she managed to grab on to a rung. Then she hauled at the rungs to pull herself through the tunnel. She seemed as light as a feather.

She emerged into a small chamber, a cylinder maybe ten feet across. The light was a flat, fluorescent gray-white. There was an odd smell, metal and plastic, a mix of staleness and antiseptic, air that had never been breathed. The walls were thick with equipment boxes, cables, pipes, softscreens, and displays. Above her there was a partition ceiling, an open-mesh diamond grill, beyond which she glimpsed more cylindrical chambers. Ducts and pipes coated with silver insulation snaked up through gaps cut in the ceiling. There were no windows here either, and her sense of enclosure increased.

Malenfant was standing here. He bent and grabbed under her shoulders, and hauled her up as if she were a child. “How do you feel?”

“For now, fine,” she said.

He pushed himself up into the air by flexing his toes. He seemed exhilarated, boyish. As he descended, slow as a feather, he was drifting sideways; and when he landed he staggered a little. “Coriolis. Just a little reminder that we aren’t under true gravity here, but rotating.”

“Like a bucket on a rope.” .

“Yeah. This compartment is what you might call ops. Controls for the cluster, computer hardware, most of the life-support boxes. We’ll use the Earth-return module as a solar storm shelter. Come on.”

He led her to a ladder at the center of the chamber. It ran straight up through a hole in the ceiling, like a fireman’s pole.

Emma walked forward cautiously. With every step she bounced into the air and came down swimmingly slowly, and the Coriolis forces gave her a small but noticeable sideways kick as she moved. It was disorienting, every sensation subtly unfamiliar, like walking through a dream.

Malenfant grabbed the ladder and began to pull himself upward. He moved effortlessly, like a seal.

Emma took the ladder but moved much more cautiously, taking the rungs one at a time, making sure her feet were firmly anchored. With every rung she climbed the weight dropped off her shoulders. But as if in compensation the sideways Coriolis push seemed that much more fierce, a tangible sideways shove prizing her loose of the ladder.

Malenfant had grabbed on to a strut. He reached down, took her hand, and helped her float up the last few feet. She seemed to drift over the open-mesh floor like a soap bubble. Malenfant babbled about cleated shoes he had brought along, but she found it hard to concentrate.

“This is the zero G deck,” he said, “the center of gravity of the cluster, the place we’re pinwheeling around. There are two more compartments above us. In here we have everything that needs a stable platform: astronomy, navigation, radar, antennae. We even have coelostats, little devices that will spin the opposite way to the ship, if we need them.”

“Malenfant, with this act — by launching again, by absconding from Earth — you’ve wrecked Bootstrap. You know that, don’t you? They’ll take apart everything you built up.”

“But it doesn’t matter, Emma. Because we’re here, now. On our way to Cruithne, and the downstreamer artifact, and everything. Nothing else matters.” He grinned and pulled at her hand. “Come see.”

She let herself be led toward small curving windows set in the wall. Each window was a disc of darkness. She pressed her face to cool glass and cupped her hands around her eyes.

The module’s hull was a fat, curving wall. Fastened to the outside she could see thick blankets: insulation and meteorite shielding. Solar-cell wings, seen edge-on, were filmy sheets of bluish glass, and slow ripples passed along them in response to some complex vibration mode. She was almost facing the sun here; the hull and the solar wings were brilliantly lit, and she could see no stars.