The Clockwork Rocket

“So how did you get the sunstone out here in the first place?” she asked.

“The way it’s always transported: well wrapped, in small pieces.”

They reached the test rocket: a cone of hardstone about Yalda’s height. Apertures near the top revealed an intricate assembly of cogs and springs secured within. “Most of this is for attitude control,” Eusebio explained. “If the sunstone burns unevenly, that puts a torque on the rocket and the whole thing will start to swerve. The mechanism needs to detect that and respond quickly, adjusting the flow of liberator between the combustion points.”

“Detect it how?”

Eusebio took a crank from a box of tools that had been left beside the device, and began winding the main spring. “Gyroscopes. There are three wheels set spinning rapidly on gimbals; if their axes shift relative to the housing, that means the rocket is veering off a straight course.”

When he’d finished winding the spring he squatted down and gestured with the crank at the bottom of the cone, which was held half a stride above the ground on six stubby legs. “There are four dozen tapered holes drilled into the sunstone, lined with calmstone most of the way. The conical plug of sunstone that was cut out to make each hole is also lined and put back in, but with grooves carved into it that leave a gap between the pieces. The liberator flows down through the gaps and ignites the unlined part at the bottom. As the sunstone burns, the lining’s corroded, progressively exposing the fuel.”

Yalda joined him and peered up at the orderly array of not-quite-plugged holes. Sunstone lamps used the tiniest sprinkling of liberator, diluted with some kind of inert grit, to keep them blazing for a night’s performance in the Variety Hall—and they still killed a few careless operators every year. Deep inside this rocket, waiting to trickle down into the fuel, was a whole tank full of the stuff in its pure form.

“I remember when you were afraid to visit the chemistry department,” Yalda said.

“I was never afraid!” Eusebio protested. “You told me not to waste my time with chemists, because they couldn’t get their energy tables straight.”

“Yes, of course, that’s exactly what I would have said.” Yalda straightened and stepped back from the rocket.

Eusebio tossed the crank into the toolbox, then looked back across the plain toward Amando, one of the three assistants who’d been working at the site when Yalda arrived. Eusebio waved broadly with two hands, and received the same gesture in reply. Then he reached into the cone and released a lever.

“What does that do?” Yalda asked.

“One chime to ignition.”

“Thanks for the warning.”

“One chime!” Eusebio scoffed, picking up the toolbox. “We’ll be behind the barrier long before then.”

Yalda was already ten strides ahead. “Did your father really let you design his trains?” she called back to him.

“Yes, but I just tweaked someone else’s plans,” Eusebio admitted. “Trains are complicated. I wouldn’t want to have to invent them from scratch.”

When Yalda reached the truck closest to the rocket she saw the other two assistants, Silvio and Frido, lying chest-down on the tray. A sturdy timber barrier some four strides high had been attached to the side of the vehicle; the two men were propped up on their elbows behind narrow slits in which theodolites had been fitted. The theory was that the rocket would ascend vertically, run out of fuel, rise a little farther from momentum alone, then plummet back to the ground to make a crater at more or less the point from which it had risen. Knowing the height it reached would allow the team to quantify the amount of energy produced that actually ended up doing something useful. It was one thing to measure the effects of a quarter of a scrag of sunstone incinerated in a workshop experiment, where the gases produced in a sealed chamber drove a piston against a load. Expecting the same yield when gas was spilling off the sides of the rocket and fragments of heat-cracked fuel were free to sprinkle down onto the desert might be a bit optimistic.

Eusebio caught up and joined Yalda and Amando behind the shield. Amando said, “One lapse to go”; he’d synchronized his own small clock with the one Eusebio had set ticking inside the rocket. Yalda stared anxiously at the clock’s face. If the sunstone burned hotter and faster than expected, it wasn’t inconceivable that the flame could rise up and eviscerate the tank full of liberator, bringing everything together in one mighty flash when the rocket was too high for the barrier to protect them.

“What am I doing here?” she muttered, trying to decide how low to squat for safety without completely obscuring her view.

“Watching history being made,” Eusebio replied, not entirely seriously. Yalda glanced at Amando, but his face gave nothing away.

“Three, two, one,” Eusebio counted.

The barrier concealed the flash of ignition, but by the time Yalda felt the ground tremble a dazzling line of white light had risen into view. A moment later a deafening hiss arrived through the air.

Yalda shielded her eyes and sought the rocket at the top of the afterimage, but something wasn’t right; the line seared on her vision had been joined by an arc, a circle, a widening helix. Then the point of radiance that had been inscribing these curves dropped below the barrier, and the ground shuddered. She stiffened her tympanum protectively, deafening herself to the sound of the impact, then tensed for a larger explosion.

Nothing followed. Either the fuel had all been consumed, or the liberator had ended up scattered.

Yalda turned to Eusebio. He looked shaken, but he recovered his composure rapidly.

“It reached a good height,” he said. “Maybe ten strolls.”

It took them more than a bell riding around the desert before they found the remains of the rocket. If it had stayed in one piece it might have made a spectacular crater, but the fragments of hardstone casing and mirrorstone cogs strewn across the ground had barely gouged the surface, and some were already half-buried in the dust. If Yalda had stumbled upon them unawares, she would have called for an archaeologist.

“Attitude control,” Eusebio said. “It just needs some refinement.”

He left the others sorting through the debris and gave Yalda a ride back to the city.

“What does your family think about all this?” she asked him. Yalda had said nothing to Lidia and Daria, or any of her colleagues; Eusebio had asked her to hold off mentioning the project to anyone until he’d tied up various “administrative loose ends”.

“I’ve managed to convince my father that it’s worth risking the money,” he said. “Even if the world’s in no danger from the Hurtlers, anything that the travelers invent on their journey could easily double our fortune.”

“What about your co?”

“She thinks I’m crazy. But I’ve told her—and my father—that I can’t countenance bringing children into the world until this rocket’s been launched to vouchsafe their future… which seems to have made both of them happy.”

“Why?”

Eusebio buzzed amusement. “She’s glad the day’s so far away. He’s glad it’s going to be so soon.”

Yalda said nothing. Eusebio turned to her and added, “Just to be clear, she can actually wait as long as she wishes.”

Yalda fought down the urge to reply sarcastically: How generous of you. If Eusebio really was supporting his co against their father’s nagging, it wasn’t worth starting a fight with him just because he sounded smug about it.

“Are you sure this isn’t going to lose you your fortune?” she asked. “What’s the going price for a mountain these days?”

Eusebio said, “I’ve already bought mining licenses from all the Councils that claim jurisdiction. It wasn’t cheap, but it didn’t ruin me.”

Mount Peerless was almost equidistant from five different cities; the only way to ensure an undisputed title would be to pay them all off. Yalda said, “Doesn’t a mining license include some deal about a share of the profits?”

“Of course. And if I do make any money from the project, I’ll give the Councils their cut.”

“But they all think you’re planning to dig out the sunstone and sell it?”

“I haven’t disabused them of that assumption.” The truck shuddered on the stony track. “But do you really want me to try lecturing my fellow Councilors on rotational physics? My father was willing to take my word for it—