Arkady nodded. “I see your point.”
On and on they talked, hashing over every point of it. The land they passed over, flat and immobile, looked different to Nadia now. It was seeded, fertilized; it was going to change, now, inevitably. They talked about the other parts of Sax’s terraforming plans, giant orbiting mirrors reflecting sunlight onto the dawn and dusk terminators, carbon distributed over the polar caps, areothermal heat, the ice asteroids. It was all really going to happen, it seemed. The debate had been bypassed; they were going to change the face of Mars.
• • •
The second evening after their momentous discovery, as they were cooking dinner in a crater’s lee anchorage, they got a call from Underhill, relayed off one of the comm satellites. “Hey you two!” John Boone said by way of greeting. “We’ve got a problem!”
“You’ve got a problem,” Nadia replied.
“Why, something wrong out there?”
“No no.”
“Well good, because really it’s you guys who have the problem, and I wouldn’t want you to have more than one! A dust storm has started down in the Claritas Fossae region, and it’s growing, and coming north at a good rate. We think it’ll reach you in a day or so.”
“Isn’t it early for dust storms?” Arkady asked.
“Well no, we’re at Ls = 240, which is pretty much the usual season for it. Southern spring. Anyway, there it is, and it’s coming your way.”
He sent a satellite photo of the storm, and they studied their TV screen closely. The region south of Tharsis was now obscured by an amorphous yellow cloud.
“We’d better take off for home right now,” Nadia said after studying the photo.
“At night?”
“We can run the props on batteries tonight, and recharge the batteries tomorrow morning. After that we may not have much sunlight, unless we can get above the dust.”
After some discussion with John, and then with Ann, they cast off. The wind was pushing them east-northeast, and on this heading they would pass just to the south of Olympus Mons. After that their hope was to get around the north flank of Tharsis, which would protect them from the dust storm for at least a while.
It seemed louder flying at night. The wind’s rush over the fabric of the bag was a fluctuating moan, the sound of their engines a pitiful little hum. They sat in the cockpit, lit only by dim green instrument lights, and talked in low voices as they moved over the black land below. They had about 3,000 kilometers to go before reaching Underhill; that was about 300 hours of flying time. If they went round the clock, it would be twelve days or so. But the storm, if it grew in the usual pattern, would reach them long before then. After that . . . it was hard to tell how it would go. Without sunlight the props would drain the batteries, and then—”Can we just float on the wind?” Nadia said. “Use the props for occasional directional nudges?”
“Maybe. But these things are designed with the props as part of the lift, you know.”
“Yeah.” She made coffee and brought mugs of it up to the cockpit. They sat and drank, and looked out at the black landscape, or the green sweep of the little radar screen. “We probably ought to drop everything we don’t need. Especially those damned windmills.”
“It’s all ballast, save it for when we need the lift.”
The hours of the night wore on. They traded shifts at the helm, and Nadia caught an uneasy hour’s sleep. When she returned to the cockpit, she saw that the black bulk of Tharsis had rolled over the horizon ahead of them: the two northernmost of the three prince volcanoes, Ascraeus Mons and Pavonis Mons, were visible as humps of occluded stars, out at the edge of the world. To their left Olympus Mons still bulked well above the horizon, and taken with the other two volcanoes, it looked as if they flew low in some truly gigantic canyon. The radar screen reproduced the view in miniature, in green lines on the screen’s gridwork.
Then, in the hour before dawn, it seemed as though another massive volcano were rising behind them. The whole southern horizon was lifting, low stars disappearing as they watched, Orion drowned in black. The storm was coming.
It caught them just at daybreak, choking off the red in the eastern sky, rolling over them, returning the world to rusty darkness. The wind picked up until it swept them along in a muted roar from the land below. The view out the windows was of a few meters of swirling yellow dust, like a close-up of the clouds of Jupiter. Eddies twisted the dirigible’s frame and the gondola trembled and bounced.
They were lucky north was the direction they wanted to go. At one point Arkady said, “The wind should hopefully wrap around the north shoulder of Tharsis.”
Nadia nodded silently. They hadn’t gotten the chance to recharge the batteries after the night’s flight, and without sunlight the motors wouldn’t run too much longer. “Hiroko told me sunlight on the ground during a storm is supposed to be about fifteen percent of normal,” she said. “Higher there should be more. So we’ll get some recharge, but it’ll be slow. Could be that over the course of the day we might get enough to use the props a bit tonight.” She flicked on a computer to do the calculations. Something in the expression on Arkady’s face— not fear, not even anxiety, but a curious little smile— made her aware of how much danger they were in. If they couldn’t use the props, they wouldn’t be able to direct their movement, and they might not even be able to stay aloft. They could descend, it was true, and try to anchor, but they had only a few weeks’ more food, and storms like these often persisted for two months, sometimes three.
“There’s Ascraeus Mons,” Arkady said, pointing at the radar screen. “Good image.” He laughed. “Best view of it we’re going to get this time around, I’m afraid. Too bad, I was really looking forward to seeing them! Remember Elysium?”
“Yeah yeah,” Nadia said, busy running simulations of the batteries’ efficiency. Daily sunlight was near its perihelion peak, which was why the storm had started in the first place; and the instruments said that about 20 percent of full daylight was penetrating to this level (it felt to her eye more like 30 or 40); therefore it might be possible to run the props half the time, which would help tremendously. Without them they were losing altitude although that might just be the ground rising under them. With the props they might be able to hold a steady altitude, and influence their course by a degree or two.
“How thick is this dust, do you think?”
“How thick?”
“You know, grams per cubic meter. Try to get Ann or Hiroko on the radio and find out, will you?”
She went back to see what they had on board that could be used to power the props. Hydrazine, for the bomb-bay vacuum pumps; the pump motors could be wired to the props, probably. Then there were spare solar panels, and the solar panels in the emergency kit. If she could get them outside she could run whatever extra insolation they caught into the prop batteries. Also, in a sandstorm like this there was light coming from all directions, so some should probably be pointed down. As she rooted through the equipment locker looking for wire and transformer sand tools she told Arkady the idea, and he laughed his madman laugh. “Good idea, Nadia! Great idea.”
“If it works.” She rummaged through the tool kit, sadly smaller than her usual supply. The light in the gondola was eerie, a dim yellow glow flickering with every gust. The view out the side windows shifted from pockets of complete clarity, with thick yellow clouds like thunderheads sailing north with them, to complete obscurity, all the window surfaces streaming with dust that wormed and spun like a particularly unpleasant screensaver. Even at twelve millibars the blast of the wind was tossing the dirigible about; up in the cockpit Arkady was cursing the autopilot’s insufficiency. “Reprogram it,” Nadia called forward, and then remembered all his sadistic simulations on the Ares, and laughed out loud: “Problem run! Problem run!” She laughed again at his shouted curses, and went back to work. Arkady yelled back information from Ann. The dust was extremely fine, average particle size about 2.5 microns; total column mass about 1-3
grams per cm-2, pretty evenly distributed from top to bottom of the column. That wasn’t so bad; drop it on the ground and it would be a really thin layer, which was consistent with what they had seen on the oldest freight drops at Underhill.
When she had prepped all the solar panels she banged down the passageway to the cockpit. “Ann says the winds will be slowest close to the ground,” Arkady said.
“Good. We need to land to get the panels outside.”
So that afternoon they descended blind, and let the anchor drag until it hooked and held. The wind here was slower, but even so Nadia’s descent in the sling was harrowing. Down and down into rushing clouds of yellow dust, swinging back and forth . . . and there it was right under her boots, the ground! She hit and dragged to a halt. Once out of the sling she found herself leaning into the wind; thin as it was it still struck like blows, and her old feeling of hollowness was extreme. Visibility billowed back and forth in waves, and the dust flew past so fast it was disorienting— on Earth a wind that fast would simply pick you up and throw you, like a broom-straw in a tornado.
But here you could hold your ground, if only just. Arkady had been slowly winching the dirigible down on the anchor line, and now it bulked over her like a green roof. It was weirdly dark underneath it. She unreeled the wires out to the wingtip turboprops, taped them to the dirigible and crimped them to the contacts inside, working fast to try to reduce their exposure to dust, and to get out from under the Arrowhead, which was bouncing on the wind. With difficulty she drilled holes in the bottom of the gondola fuselage, and attached ten solar panels with screws. As she was taping the wiring from these to the plastic fuselage, the whole dirigible dropped so fast that she had to collapse onto her face, her whole body spread-eagled on the cold ground, the drill a hard lump under her stomach. “Shit!” she shouted. “What’s wrong?” Arkady cried over the intercom. “Nothing,” she said, jumping up and taping faster than ever. “Fucking thing— it’s like working on a trampoline—” Then as she was finishing the wind picked up strength yet again, and she had to crawl back down to the bomb bay, her breath rasping in and out of her.
“The damn thing almost crushed me!” she shouted forward to Arkady when she had her helmet off. While he worked to unhook the anchor she staggered around the interior of the gondola, picking up things that they wouldn’t need and taking them into the bomb bay: a lamp, one of the mattresses, most of the cooking utensils and dinnerware, some books, all the rock samples. In they went, and she jettisoned them happily. If some traveler ever came upon the resulting pile of stuff, she thought, they would really wonder what the hell had happened.
They had to run both props full out to get the anchor unhooked, and when they succeeded they were off and flying like a leaf in November. They kept the props on full, to gain altitude as fast as possible; there were some small volcanoes between Olympus and Tharsis, and Arkady wanted to pass several hundred meters over them. The radar screen showed Ascraeus Mons falling steadily behind. When they were well north of it they could turn east, and try to chart a course around the northern flank of Tharsis, and then down to Underhill.
But as the long hours passed they found that the wind was rushing down the north slope of Tharsis, across their bow, so that even when running full power toward the southeast, they were still only moving northeast at best. In their attempts to fly across the wind the poor Arrowhead was bouncing like a hang glider, yanking them up and down, up and down, up and down, as if the gondola were indeed attached to the underside of a trampoline. But despite all that, they still weren’t going in the direction they wanted to go.
Darkness fell again. They were carried farther northeast. On this heading, they were going to miss Underhill by several hundred kilometers. After that, nothing; no settlements at all, no refuge. They would be blown over Acidalia, up onto Vastitas Borealis, up to the empty petrified sea of black dunes. And they did not have enough food and water to circumnavigate the planet again and give it another try.
Feeling dust in her mouth and eyes, Nadia went back to the kitchen and heated them a meal. Already she was exhausted, and, she realized as the smell of food filled the air, extremely hungry. Thirsty, too, and the water recycler ran on hydrazine.
Thinking about water, an image came to her mind, from the trip to the north pole: that broken permafrost gallery, with its white spill of water ice. Now how was that relevant?
She worked her way back up to the cockpit, holding onto a wall with every step. She ate a dusty meal with Arkady, trying to figure it out. Arkady watched their radar screen, saying nothing, but he was looking concerned.
Ah. “Look,” she said, “if we could pick up the signals from the transponders on our road to Chasma Borealis, we could come down and land by it. Then one of the robot rovers could be sent up to get us. The storm won’t matter to the robot rovers, they don’t go by sight anyway. We could leave the Arrowhead tethered, and drive back home.”
Arkady looked at her, finished swallowing. “Good idea,” he said.
• • •
But only if they could actually pick up the road’s transponder signals. Arkady flicked on the radio and called Underhill. The connection crackled in a storm of static almost as dense as the dust, but they could still make themselves understood. All through that night they conferred with the crowd back home, discussing frequencies, bandwidths, the power of the dust to mask the transponder’s fairly weak signals, and so on. Because the transponders were designed only to signal rovers that were nearby and on the ground, it was going to be a problem hearing them. Underhill might be able to pinpoint their location well enough to tell them when to descend, and their own radar map would give them a general fix on the road’s location as well; but neither of these methods would be very exact, and it would be almost impossible to find the road in the storm if they didn’t land right on it. Ten kilometers either way and it would be over the horizon, and they would be out of luck. It would be a lot more certain if they could just latch onto one of the transponder signals, and follow it down.
In any case, Underhill dispatched a robot rover on the road north. It would arrive in the area of the road they were expected to cross in about five days; at their current speed they would cross the road themselves in about four days.
When the arrangements were finished, they traded watches through the rest of the night. Nadia slept uneasily on her off watches, and spent much of the time lying on the bed feeling the wind bounce her. The windows were as dark as if curtains had been drawn. The roar of the wind was like a gas stove, and then occasionally like banshees; once she dreamed they were inside a great furnace full of flame demons, and woke sweating, and went forward to relieve Arkady. The whole gondola smelled of sweat and dust and burnt hydrazine. Despite all the gaskets’ micron seals, there was a visible whitish film on all the surfaces inside the gondola. She wiped her fingers across a pale blue plastic bulkhead, and stared at her fingers’ mark. Incredible.
They bounded along through the gloom of the days, through the starless black of the nights. The radar showed what they thought was Fesenkov Crater, running under them; they were being carried northeast still, and there was absolutely no chance they would be able to buck the storm and get south to Underhill. The polar road was their only hope. Nadia occupied her off watches by looking for things to throw overboard, and cutting away at parts of the gondola frame she judged inessential, until the engineers in Friedrichshafen would have shuddered. But Germans always overengineered things, and no one on Earth could ever really believe in Martian g anyway. So she sawed and hammered until everything inside the gondola was latticed nearly to nothing. Every use of the bay brought in another small cloud of dust, but she figured it was worth it; they needed the loft, her solar panel arrangement was not getting sufficient power to the batteries, and she had tossed everything not attached to the hull long before. Even if she had had them, she would not have gone back under the dirigible to install them; the memory of the incident still gave her the shivers. Instead sh
e kept cutting further and further. She would have tossed out pieces of the dirigible frame too, if she could have gotten into the ballonets.
While she did this Arkady padded around the gondola cheering her on, naked and dust-caked, the red man incarnate, singing songs and watching the radar screen, jamming down quick meals, planning their course such as it was. It was impossible not to catch a bit of his exhilaration, to marvel with him at the strongest buffets of the wind, to feel the dust flying wild in her blood.
And so three long intense days passed, in the grip of the dark orange wind. And on the fourth day, a bit after noon, they turned the radio receiver up to full volume, and listened to the crackly roar of static at the transponders’ frequency. Concentrating on the white noise made Nadia drowsy, for they had had very little sleep; she was almost unconscious when Arkady said something, and she jerked up in her seat.
“Hear it?” he asked again. She listened, and shook her head. “There, it’s a kind of ping.”
She heard a little bip. “Is that it?”
“I think so. I’m going to get us down as fast as I can, I’ll have to empty some of the ballonets.”
He tapped away at the control keyboard, and the dirigible tilted forward and they began to drop at emergency speed. The altimeter’s numbers flickered down. The radar screen showed the ground below to be basically flat. The ping got louder and louder— without a directional receiver, that was going to be their only way to tell if they were still approaching it or moving away. Ping… ping… ping… In her exhaustion it was hard to tell whether it was getting louder or softer, and it seemed every beep was a different volume, depending on the attention she could bring to bear.
“It’s getting softer,” Arkady said suddenly. “Don’t you think?”
“I can’t tell.”
“It is.” He switched on the props, and with the whir of the motors the signal definitely seemed quieter. He turned into the wind, and the dirigible bounced wildly; he fought to steady its downward movement, but there was a delay between every shift of the flaps and the dirigible’s bucking, and in reality they were in little more than a controlled crash. The ping was perhaps getting softer at a slower rate.