She extended her arms then to the sides like a bird spreading its wings, sliding them into insulated tunnels where they rested comfortably on inflated supports. For a moment she thought that some little stones had somehow made their way onboard and gotten trapped under her arms. Then one of them shifted a little, and she realized that this was the suit again, sensing the pressure of a rock on the underside of the wing and mirroring it.
The insulation also helped to deaden sound, and so she could now hear almost nothing from outside.
Which didn’t mean she couldn’t hear anything. She could hear the wind. A phrase that didn’t really do justice to the soundscape now being rendered by the array of miniature speakers. “The canid smelled the forest” was a completely different sentence from “The man smelled the forest,” not because the words had different meanings, but because the canid’s olfactory apparatus was infinitely superior to that of the man. In a loosely analogous way, the real-time, three-dimensional sonic portrait of the wind generated by the glider’s onboard systems and rendered by the helmet’s speakers was as far beyond what she could sense with unaided ears as the canid’s scenting of the forest was beyond the man’s. For the vehicle had lidars pointed in all directions, looking out into the air to a range of several hundred meters and seeing its myriad currents, shears, and vortices. To convey all of that information in sound was impossible, but what came through was more than enough to tell Kath Two where she wanted to go: namely, where the energy was. And right now the symphony of tones, whooshes, crackles, and rustlings told her that her intuition yestereve had been more or less correct. The wind climbed the slope from the lake in a fairly continuous sheet, but as it molded itself over the brow of the hill, the wind higher up, on the outside track, had to go faster in order to keep up with the ground layer. There was a gradient in speed between the wind aloft and that at the ground. She could use it.
Her eyes were busy too, tracking a pair of birds flying parallel to the slope, dipping in and out of the shear in the wind, sipping power. Far above them, the clouds were telling her a story about the conditions she’d be facing in a few minutes’ time, but this was no concern of hers now.
The wind gusted. The feeling of pressure beneath her arms increased and at the same time she felt the entire craft rising. She moved her feet and her hands in a way that the suit recognized and transmitted to the glider’s control surfaces. Just that quickly, it was configured for lift. Biting suddenly into the wind coming up the hill, the craft sprang into the air; she could feel the knots of pressure vanish as the ground lost contact with the wings. Then the only sensations on the skin of her arms were caused by the wings reading the currents of air flowing over them. She let herself rise high enough to buy some margin of error, then dropped the nose and glided down the hill, trading altitude for velocity. The game she’d be playing for the rest of the day was to build up a fund of energy by stealing it from the atmosphere. At the end she would trade it all for altitude, and spiral up to a place where the atmosphere failed.
Closer to the shore of the lake, the meadow gave way to trees. This was one of the more mature forests on New Earth. It had been seeded only a few years after the First Treaty, about a hundred years ago. She pulled the nose up, skimmed over the highest branches, then dropped again until she was gliding over the blue water of the lake: the melted core of a comet, still coming alive with seeded algae and fish. With a voice command she caused the glider to drop a tube, no thicker than her finger, into the water skimming by a few meters below. On her first pass across the lake’s diameter she collected twenty kilograms of water, which slowed the glider down somewhat. She found a thermal on the other side and rode it up a few hundred meters before rolling over and diving down for another, faster pass over the lake, and another long drink of water. This part of the journey was the most ticklish, so it was good that it came first, when she was still fresh. A glider that was light enough to carry around on her back was, by the same token, too light to store very much kinetic energy. Its lack of momentum placed limits on the maneuvers Kath Two could perform in the higher atmosphere; small twitches in the flow of air would bat it around like a feather. It needed to get a lot heavier. The way to do that was to scoop water out of a lake, as she was doing now. But it all happened at low altitude and low speed, where the margin for error was slender. The first few passes, when the glider weighed practically nothing, were the most delicate. So she took her time at each side of the lake to find good thermals and harvest their force. After an hour of that, however, she was dive-bombing her way across the crater with terrific authority, carrying hundreds of kilograms of ballast in the belly and the wings. By then she had learned where to hunt for thermals that, as the morning wore on, bloomed with increasing vigor from the open meadows in the shoulders of the great crater.
It was on her last pass, just as she was getting ready to pull up and skim over the tops of the trees that grew from the onrushing shore, that she saw the human.
The human was not exposed on the shore, but standing back among the first line of trees, apparently watching her. He or she—the distance was too great to read gender—was dressed in clothing that blended in with the surroundings. Not the bright coveralls of Survey. But neither did it look military. Perhaps sensing that he or she had been spotted, the human immediately stepped back into the young forest. At the same moment, Kath Two was obliged to pull her nose up, lest she collide with the trees. So great had been her surprise that she almost did it too late, and felt a few thin branches whipping against the belly of the fuselage as she put the lake behind her for good.
Directly ahead was a broad meadow, angled toward the sun, that she knew to be an excellent source of power. As she drew close enough for the lidars to read the air, and for her eyes to pick out the movements of the birds, she banked into the thermal. Her first approach was a crude guess based on what she was hearing, but as soon as she got into it and felt the fine-grained currents of the air in her arms and her fingertips, she was able to use it as birds did.
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.