Now they were safely down, and in exploration mode, and their settlement was still quite mobile, being almost entirely composed of landers; they had built their wind wall but not yet started on buildings. So they could make the move fairly easily.
Over the next few days, therefore, everyone in the station walked up to see the sea valley, and agreed the moment they did that the move should be made. This kind of unanimity was said to have happened so infrequently on the ship (in fact it had never happened) that the people still on the ship were happy to accede to the plan on the ground.
“As if we could stop them,” Freya remarked to Badim.
Badim nodded. “Aram says they are acting ominously autonomously. But it’s okay. We’ll all be down there soon. And it looks like a good place.”
At this point, people from the ship were being ferried down to the moon in modules that then served as their living quarters. Nothing was going as quickly as many on the ship would have liked, but everyone had to agree that nothing more could be done to speed the process. They only had so many ferries, and then some had to be refueled and launched back up to ship. Now that they were going to move the settlement to Half Moon Valley, all the work to expand their living space would be delayed. But a brief delay was felt to be well worth it, given the many advantages that would follow the move.
So the settlers got to work moving, a task that seemed easy until they began to do it, when the little declivities and breaks in the burren turned out to be more obstructive to moving their living modules than had been foreseen. The shallow little grabens were easy to walk down small ravines into and out of, and so they had hiked to the valley and back without impediment, but moving their modules on wheeled frames, and their construction robot vehicles, and even their rovers, across them was not so easy. And the grabens were all so long, and trending east-west, that they often could not be flanked.
A best route was found that crossed as few of these troughs as possible, using the algorithm that solves the traveling salesman problem, notorious to all those worried about errors endemic to certain greedy algorithms. But even after extensive cross-checking, the minimum number of graben crossings turned out to be eleven. Each trough had to be bridged, and this was not easy, given the dearth of bridge materials and the weight of the loads on the wheeled carts.
So it was a slow and ponderous trek, and soon after they began, sunset came again. They did not let this stop them, having decided they could make their trip by the light of E. It hung up there in its usual spot, half illuminated—what on Earth they called a quarter moon, an unusually logical name, it must be said. Just after sunset was as dark as the nights got, as E waxed to full and then waned to the other quarter moon before sunrise. The light cast by quarter E was around 25 lux, which was 25 times the illumination of the full moon on Earth; and though it was four thousand times less than direct sunlight on Earth, and six thousand times less than full taulight on Aurora, it was still about the same illumination as a nicely lit room at night in the ship, which was certainly enough to see by. So they worked in this light, and formed a long caravan of their vehicles, and headed north over the burren. In the end they declared the E light quite beautiful, easy on the eyes, things slightly drained of color but extremely distinct.
Euan and the rest of the bridge-building team went into action when they came to the edge of the first trough. One of them drove a stone-cutting vehicle to the edge of the trough, well away from where they intended to cross, and put to work a rock saw attachment at the end of the vehicle’s backhoe. Cubes of rock were cut from the side of the graben, then lifted and conveyed hanging from the backhoe to a steep-walled section of graben, where the opposite side was both close and as vertical as could be found. The first cube was hard to get loose, but with some knocking with the side of the backhoe they managed it. Cubes three meters on a side were as large as the vehicle could safely lift. When they got them to the edge of the graben they lowered them into the trough, all very slowly, especially if the wind was gustier than usual. Every four or five cubes, they had to stop and swap out the saw blades they were using, both the circular blades and the thin up-and-down saws that Euan called dental floss. Their printer refurbished worn blades with new synthetic diamond edges, and they attached these and continued cutting cubes and depositing them in the trough to make a rough ramp. When the ramp extended far enough into the trough that the vehicle arm couldn’t reach out far enough to place new cubes, they filled the gaps between cubes with gravel that other teams had crushed, then unrolled by hand an aluminum mesh carpet to provide a bridge surface smooth enough to drive onto. Euan then drove the cutter vehicle out onto this ramp, another cube dangling heavily from its front end, everything looking precarious, especially when swaying in hard gusts of wind, until he reached the leading edge of the new ramp and could lower the next cube of rock into place.
They were nearly done with this first ramp when Eliza dropped a new cube into place without realizing the trough bottom was not smooth. This was perhaps a result of them working in E light, but in any case, the new cube tilted into another cube already in place in a way that meant their vehicle could neither lift it nor move it, without dangerously tipping the vehicle.
Euan took over the controls from Eliza to give it a try, but he couldn’t move it either, though he rocked the vehicle dangerously to the side. So it lay there blocking their way, making the ramp impassable, and tilted as it was, it looked like they would have to abandon the entire ramp and start over.
“Let me try something,” Euan said, and used the rock saw to cut a trapezoidal segment off the top of the tilted cube, then carefully wedged the segment into the gap left under the tilted cube. After attaching the pile-driver tip and doing some hard tamping with the crane, they concluded the combination was going to be stable enough to drive over, and so they continued cutting cubes and placing them in the trough, more carefully than ever, often with Euan given the controls to make the final drops.
“He’s an artist,” Badim said to Freya as they watched from the ship.
“That’s why he’s down there and I’m not,” Freya said. “They don’t need Good For Anythings down there.”
“They do,” Badim said. “They will. It was a lottery, remember.”
After three days of work, the ramp across the trough was finished. They sent across a robot truck first to test it, and it ground over the aluminum carpet without incident. All was well, and they drove or directed all the other vehicles over the ramp. There were thirty-seven vehicles in their caravan, ranging in size from four-person rovers to mobile containers that were the modular parts of their buildings. All crossed without incident. But that was only the first of eleven grabens.
However, they now had their method, and because of that, the subsequent ramps went a little faster. Even the so-called Great Trench, a graben three times wider and twice as deep as the rest, was ramped and crossed in a day. Stopping to swap out the rock-cutting blades became the biggest delay. In this task, both the versatility and the unreliability of humans doing mechanical work was revealed. The operator would set the vehicle arm on the ground with the nut holding the blade to the rotor facing up, and someone would fit the power wrench to the nut and zip it off with a pneumatic blast. Off came the nut and washers, after which they spun the circular saw blade carefully off the short spindle, being careful not to damage its screw threads. Then they carried the blade to the machine truck, where printers would have readied a newly sharpened blade. Go back and spin a refurbished blade down onto the spindle, put the washers on, then the nut; last, apply the power drill and tighten the nut. This was the moment where humans were not as good as a robot would have been, and their tools not adequate to compensate for their inexperience. The problem was they could not tell how tight the nuts were being screwed on by the power drill, and very often, in the attempt to be sure they were tight enough, they drilled them too tight. Threads were stripped, and then there was no grip at all, and the spindle had to be replaced, which took many hours of delicate work; or washers were fused together, or fused into the nut or the blade, such that they could not be separated afterward, even with the power drill at full power.