Greg Egan - The Clockwork Rocket

Yalda cast another few stones—imagining them heavier in the hope of tricking her body into dispensing a little more force. The sack was a quarter full. She believed she was still heading away from the mountain, but judging tiny changes in the view at this distance was almost impossible.

How could they keep a lookout for fires? From a cage tethered on a rope, high above the surface, stabilized… somehow. Once the mountain was spinning, though, the problem wouldn’t be stability, but the strength of the rope.

And once the mountain was spinning, it would be far harder to move around on the surface. Weightlessness had made it difficult enough, but every part of the slope would be transformed into a ceiling. How did you douse a raging fire on a ceiling?

The sack was empty. Yalda clutched it to her chest, unwilling to presume that she’d have no further use for it. Was she moving toward the mountain, or away from it? For some time now, she hadn’t discerned any change in the angle it occupied in the sky, but she’d been too distracted to give the task much thought. She needed to pick a few distinctive stars close to the edge of the mountain, then wait to see if they crept away from it, or whether its silhouette slowly grew and hid them.

Yet another flash of light came from the mountain, this one very close to one of the worksites. Perhaps someone there, outside the tunnel on catapult duty, would have seen it? Yalda counted the pit-lights down from the summit, and realized that the site was her own.

The light winked again, from exactly the same direction. Not an impact, then. By now, she realized, her team would be out scouring the area for her, their sunstone lamps occasionally turning up into the sky. Yalda pictured them inspecting the catapult, feeling how loose it was, wondering if anyone could possibly have been careless enough—

The same light appeared, brighter than before, crossing her line of sight so slowly that it dazzled her. When she completed a half-turn it struck her rear gaze and stayed—wandering a little, but never fading out completely.

The lamp wasn’t on the surface of the mountain; it was moving straight toward her through the void. And it couldn’t be aiming itself, searching her out itself.

Yalda spread the empty sack out in front of her, hoping to make a larger, more reflective target. The approaching light began wavering oddly, as if seen through a heat haze. Through a burst of air, spreading out through the void. Some beautiful idiot had come after her—launched along the same trajectory by the catapult—and now they were using compressed air to brake. Not from a tiny canister like her own, but from one of the giant cylinders that powered the jackhammers.

The dazzling light overshot her, passing to one side. It rebounded, then overshot in the other direction. It was excruciating, but Yalda could do nothing to meet her rescuer halfway. By trial and error, by eye and airburst alone, the distance and difference in speed that separated them was whittled down to the point where the lamp became superfluous and its owner shut it down. No longer blinded by its glare, by starlight alone Yalda could see the figure before her, clutching an air tank and a coil of rope, wrapped in a familiar cooling bag.

Fatima took hold of a portion of the coiled rope and tossed it toward Yalda. This sent her gliding backward, but she didn’t bother trying to compensate, she just let the rope uncoil. Yalda reached out and grabbed the end, then brought it around her waist twice and held on tight.

There was a jolt as the rope went taut, then they were bound together, moving in a broad circle around a common point. Yalda dragged herself along the rope a short way, then gestured to Fatima to use an airburst to get rid of some of their angular momentum. By the time they were within arms’ reach of each other, their spin was almost gone.

Fatima took hold of Yalda’s helmet and pressed it against her own. “Help me get down. Please.”

She sounded terrified, and for a moment Yalda couldn’t reply. How could she have come after her at all, if she was so afraid?

“Let me take the canister from you,” Yalda suggested gently. “Don’t release it until I’m holding it.”

Fatima had two arms wrapped around the cylinder. Yalda embraced it herself the same way, then eased it out of Fatima’s grip.

With her other hands, she rearranged the rope, forming two coils and bringing them around their bodies, then securing the connection with a series of knots. Fatima was shivering; she’d already done more than Yalda could have asked of anyone. It was her own job now to get them safely down.

“I keep thinking about Benedetta,” Fatima said. “Landing is the hardest thing.”

“This won’t be like that,” Yalda promised. “No fire, no heat, no danger—” She noticed the sunstone lamp still strapped to Fatima’s shoulder. “We won’t need that anymore.” She pulled it loose and swatted it gently away into the void; with all the jarring it had suffered already, it was a miracle it hadn’t exploded.

Yalda found her target on the horizon and opened the valve on the air cylinder a notch; the effortless kick against her arms was the most beautiful sensation she’d ever felt. She’d never know if she’d already been heading back toward the ground before Fatima reached her; she didn’t want to know.

A pinprick of light appeared on the dark rock below them. “Did you see that?” Yalda asked Fatima. She’d been hoping that she might have been delirious before—or that Fatima’s ascent might have included enough unlikely swerves for her search lamp to account for everything.

“Yes. What was it?”

“I have no idea,” Yalda lied. “Don’t worry; we’ll work it out later.”

As the mountain loomed closer, the line of worksites spread out beneath them, the most distant fading to black. Yalda made a sideways correction, steering them toward the mouth of their own tunnel. When that patch of bright rock began to grow alarmingly, she squirted air down, slowing their descent. For a pause or two she thought she might have overdone it and launched them away from the mountain again, but they were close enough now that the cues did not remain ambiguous for long. She used another quick burst to slow their horizontal motion, lest they scrape all their skin off on the rock.

As the guide rails running past the tunnel mouth rushed into view, Yalda discerned a new feature: the team had tied dozens of lengths of rope to the rails, spread out along a couple of stretches, pointing away from the rock with their free ends high above the ground. If she could steer into this soft, forgiving fence—

“Try and grab the ropes!” she urged Fatima, as they swooped toward them. “The more arms to share the jolt, the better.”

A flicker before the glorious fool-catcher came within reach, Yalda used a tiny kick from the cylinder to give them a slight upward velocity. Then she dropped the cylinder and flailed around, managing to seize one of the ropes. Fatima had gripped another one, in two places. Yalda brought all her own hands onto her rope before it went taut; the shock to her joints made her cry out in pain, but she didn’t lose hold of it.

They were a few strides above the guide rails. Yalda had been expecting to have to drag herself hand-over-hand down to the ground, but the ropes’ elastic tug had delivered a little more force than was needed to stop them, and they were actually drifting slowly toward the surface.

Fatima began humming from the shock. Yalda almost joined her, but she was afraid that if she started she’d never stop.

She said, “We’re safe. You did it, my friend, and now we’re both safe.”

18

Lavinio said, “Without gravity, I think this is the best we can do.”