Half an hour’s climbing left the lake a blue disk far below and put her in sight of open country to the southeast, dotted with mushroom-cap clouds that were a dead giveaway. Trading altitude for distance, she glided in a nearly straight line until she could pick up those thermals and recharge her store of energy. She had her eye on a range of mountains several hundred kilometers distant, rising up above the eastern shore of the Pacific Ocean. Above them, clouds were arranged in long folds, running parallel to the crest of the range.
The photocells in the wings had stored up enough power now that she was able to send a burst of data up into space. Packets coming back a few seconds later told her when and where she could expect hangers along her projected route. It was too early to lock in on a specific plan, but useful to get a general picture. And it was good practice to let people know where she was and when to expect her.
It looked like about twenty other surveyors were operating in the same general zone. She considered the number astonishingly high, and double-checked it. While she was waiting for confirmation to come back, she scanned the skies around her and spotted two of them.
After some thought, she sent a voice message to Doc. “I want to talk to you when I get back. Not urgent. But important.”
Then she put such distractions out of her mind and attended to the problem at hand, which was stringing together enough thermals to get her into the mountain wave that awaited her downrange. Once she had stored enough energy in her glider — mostly in the form of altitude — the thermal-riding part of it became nearly automatic and she was able to doze off for stretches of twenty minutes at a time.
In truth, there was no aspect of this flight that could not have been managed by a robot. Robot gliders were at this moment operating all over New Earth. But she was leery of letting her own powers dwindle by delegating them to machines, and so she liked to fly the glider at least part of the time. The algorithms worked, but they wouldn’t get better unless humans gardened them; and to do that, you had to fly.
A surge of acceleration awakened her from an early afternoon nap and she looked down to see the snow-covered peaks of the mountains a thousand meters below her. She had found the mountain wave, a source of sustained atmospheric power that dwarfed anything that could be obtained from thermals. It was a ridge of rising air running from north to south. If she turned north from here, she could probably ride it all the way to the polar vortex, and take that up to where the atmosphere failed. But she had farther to go than wings could take her, so she banked south and trimmed the glider to slip sideways along the wave, skimming enough power from it to gain altitude even while screaming southward at three hundred kilometers an hour. She was a fly hitching a ride on a hurricane.
Knots in the tapestry of sound told her of other solid objects above and below, left and right. She was able to pick them out visually as the setting sun lit up their fuselages and wingtips against the deep purple of the sky.
Higher yet — unfathomably far above, and yet only in “low” Earth orbit — were larger structures, moving more slowly, like the minute hands of great clocks. Linear constellations with fatter, brighter lights on their ends. One of them was sweeping across the sky directly south of her, and she knew she was already too late to catch it. But looking off to the west she saw another approaching, like a giant leg striding across the sky, its foot swinging downward, not yet planted. She didn’t even need to check the params to know that this was the hanger for her. But she ran the calculation anyway, partly to confirm her guess and partly as a courtesy to other aircraft in this crowded space that might be aiming for the same one.
Darkness fell before she reached it. The hanger — it was a pun on “hangar,” a term from Old Earth aviation — was a big hollow pod hanging on the end of a tether that, just now, extended far up into space. At its opposite end, thousands of kilometers above, was another hanger just like it, serving as a counterweight. The two hangers formed a bolo, rotating around each other to keep the tether stretched tight between them. The bolo orbited the Earth just like any other satellite, the difference being that the height of that orbit, and the length of the tether, had been tuned so that on every rotation — or, as it appeared from Kath Two’s point of view, each long stride across the heavens — the hanger on the low end would swing down into the uppermost reaches of the atmosphere and seem to hover, almost still, for a minute. Somewhat analogous to the way that a runner’s foot will remain planted on the ground, unmoving, for an instant during each stride, even though the runner is traveling swiftly. In any case it came low enough and went slowly enough that a glider, pumped to great velocity and brought high into the atmosphere by the power of the mountain wave, could catch it and match it.
Kath Two’s eyes and ears told her of other vehicles converging on the same target. A few minutes prior to rendezvous, it became obligatory to hand control of the craft over to a version of the ancient program Parambulator, which managed the final approach. Kath Two could have stuck the landing without assistance, had she been alone. But coordinating her approach with the other vehicles was the sort of task best left up to a five-thousand-year-old algorithm.
At the time she ceded control, the hanger still seemed impossibly far away, but over the next few minutes it loomed out of the sky like a slow-motion meteorite, studded with red running lights. It was shaped like a rugby ball, streamlined fore and aft, with stubby winglets that were finding traction in the thin air, adjusting their angles of attack to stabilize its flight. Kath Two and the other aircraft were converging on it from behind, overtaking it rapidly as it slowed almost to a stop.
Most of the hanger’s aft end was a broad aperture that now irised open to reveal a spacious deck, brightly illuminated, like a magic doorway hanging in the sky. In front of her she could see the lights of other vehicles sidling into the queue ahead of her.
The hanger’s bright orifice grew huge, like a chilly sun falling out of the sky. One by one the vehicles slipped into its lee and bounced and skidded to a stop on its deck. From a distance this appeared level. In fact it was angled slightly upward, so that the aircraft climbed a gentle ramp as they rolled into it. This helped them kill their excess velocity. Her glider bounced twice before the ramp took its weight. Then gravity — real and simulated — came down like a fat hand on her back, and she felt a rush of blood to the head as the glider slowed sharply.
Visually, she was at rest now. In truth, she was contained in a revolving object: one extremity of a bolo four thousand kilometers long. Even though its revolution, seen from a distance, had looked ponderous, the bolo as a whole was wheeling fast enough to produce two gees of simulated gravity. That plus the one gee of real gravity she was feeling from New Earth added up to a massive amount of down force pressing her into the water-filled ballast sacs that made up the glider’s belly.
A human-sized grabb, untroubled by the weight, dragged her glider off to the side, making way for other aircraft coming in for a landing behind. All told, the hanger collected eight aircraft during this pass. Besides Kath Two’s, two others were piloted by humans. Each was of a different design; both were powered. The other five were robot gliders, looking similar to Kath Two’s, but solid rather than inflatable. As soon as the last of these was stowed, the hanger’s tailgate constricted and closed behind them. Its stride complete, the hanger was already swinging back, gaining altitude “heel” first, rising back up toward space.