Titan n-2

by Stephen Baxter

  But it all depended on precise navigation.

  There were actually three navigation techniques in use on Discovery: doppler, ranging, and optical navigation. The first two could be run from Earth. Doppler was a way to measure the speed the ship was approaching or receding from the Earth, and ranging exploited the finite speed of light to measure the distance from the spacecraft to the Earth. When used together, Discovery’s position and speed could be determined very accurately…

  But not accurately enough, over the billion miles Discovery was to travel. The only way was to navigate from the spacecraft itself, by the stars.

  There was a kit of hand-held gear, a sextant and low-power optical telescope, and there were camera systems. The most basic systems — and the most heavily used — were the simple light-sensing star trackers that had been installed around Discovery, in the wings and boattail and nose. Without intervention from the crew these could fix on the sun and Earth and maybe a fixed star, like Canopus, allowing Discovery to triangulate its position.

  But today something was wrong; the star trackers kept losing their locks.

  Angel — ill-tempered, impatient — probed at the problem. The trackers seemed to be picking up a lot of false images, whole constellations of them, that made it impossible for them to recognize their stellar targets. That wasn’t so unusual in itself — the spacecraft was habitually surrounded by floating chunks of debris, flecks of paint or insulation that had broken away, all of which glittered like stars in the intense sunlight — but it was unusual for such a flood of false readings to hit all the trackers, all at once. Maybe something had come loose in the cargo bay, he thought.

  Then the word came up from the ground.

  “Discovery,Houston…” They didn’t wait out the time delay for his reply. “We’ve been looking at your anomalous tracker readings. We figure that what they’re seeing is Cherenkov radiation. Repeat, Cherenkov…”

  Oh.

  Angel knew the implications.

  When a high-energy subatomic particle hit a star tracker, it could rip through the tracker’s glass window faster than the speed of light in the glass. There would be a kind of optic boom — a blue flash, a burst of Cherenkov radiation, a spark confusing the sensors.

  Cherenkov radiation meant that from some source, heavy, fast-moving particles were scouring through Discovery.

  Angel acknowledged the message, and asked for a confirmation.

  Most of the plants were growing hydroponically, with their roots bathed in a liquid nutrient solution called Salisbury/Bugbee. As a backup, others were growing in an experimental soil substitute based on zeolite granules impregnated with potassium and nitrogen and other nutrients, like little time-release pills, with enough nutrients to last years.

  In the hydroponic racks, plant stems protruded through little holes in plastic sheeting, straining up at the artificial lights. Water flowed through the solution and air bubbled up from below, while carbon dioxide was pumped in over the plants and oxygen sucked away by a miniature air conditioning system.

  Libet’s main job today was to pull out the plastic irrigation nozzles from a couple of the racks, which had become clogged. She had to disassemble the base of the rack to get to the nozzles. She opened up her toolbag. Pliers, small hammers, screwdrivers and spanners came floating out at her face, chiming gently against each other. She retrieved the tools, picking out the screwdriver she wanted, and went to work on the rack. Soon she had a handful of screws, nuts, washers and other small parts from the rack. She put all this in a pocket, carefully buttoning it up. When she’d started to work in microgravity she had tried leaving such items suspended in mid-air. But that didn’t work in the farm; if you looked away for more than ten seconds or so your nut or washer would go sailing off in the powerful breezes in here.

  Anyhow, she retrieved the nozzles; she wiped them out and replaced them. She made a mental note that in a couple of weeks, after the next wheat crop, she would have to clean out the culture media.

  If only they were using soil, she mused, then she could take off her gloves and dig in with her fingers; she would need tiny spades and forks, not spanners and screwdrivers. But at least she got to handle the little plants, the green growing things. She breathed on them, enriching their atmosphere with her carbon dioxide.

  It had taken a lot of care to select the plants. In typical NASA fashion, plants had been studied in a way traditional farmers would never have recognized, in terms of parameters like edible biomass produced per unit volume, growth period from planting to harvesting, and biologically recoverable calories.

  So there was wheat and rice, for calories, starch and protein; white potatoes for carbohydrates, vitamin C and potassium; soybeans for protein and amino acids; peanuts for protein and oil — although the peanuts were difficult to grow and harvest — lettuce for vitamin A and vitamin C.

  Wheat was the staple. They got a crop every sixty days. They even had ovens on board (fan-forced — no convection, without gravity) so they could make their own bread. And they were trying out an experimental dwarf spring wheat crop developed in Utah called Apogee, which gave a higher yield.

  The warm scent of bread filling the hab module was one of the most pacifying elements of their whole environment.

  She turned to her next chore.

  Working in microgravity presented its own challenges, as usual. She had to get some kind of foothold, so she jammed her body into the space between the racks using her muscle tension and her legs to hold herself in place. She had a lot of reach — her work envelope, as the mission planners called it, was wider than on Earth, because she could just sway from side to side as she needed to, like seaweed in a current. But her legs, holding her in place, were in tension instead of compression, as they would be on Earth, and she had to take frequent rests to relieve her muscles.

  She liked to shut out the noise of the pumps and fans of the nutrient systems and air blowers; she wore earplugs, like today, or sometimes the headset of a walkman. She found that in here she preferred thin, cold, almost abstract music: complex Bach fugues, perhaps, or late Beethoven string quartets. There was something about the voiceless, precise compositions which seemed to complement the lush warmth and visual brightness of the farm.

  She was bending the rules by wearing the plugs, though. There was a danger she wouldn’t be able to hear the master alarm, if it sounded; there were visual alarms built in here — flashing red lights fixed to the walls — but, from amongst the racks, they were difficult to see.

  But Libet figured the danger was minimal. The worst that could happen was probably a micrometeorite puncture — and then she would feel any loss of pressure as rapidly as it happened — or a radiation pulse, a solar particle event. But even so she was safe; the farm was just about as heavily shielded from radiation as the hab module. Plants had higher radiation dose limits than humans, but exceeding the limits would have just as lethal effects. She would just have to wait out a storm in here, for as long as it took.

  As she worked, she thought a lot about Nicola.

  Niki’s depression seemed to be deepening. She went through the work assigned her with no enthusiasm, and not much concentration. And she was having trouble sleeping at night, and was reluctant to wake in the morning. She seemed to have no appetite — hell, none of them did — but she was a lot less determined about keeping up her diet and her fluid intake than the rest.

  Libet thought she understood. The isolation, the cramped quarters, the growing unreliability and shoddiness of their equipment — and the utter, utter impossibility of being able to get away from the others — all of that was working on them all in some way, and, it seemed to Libet, they were all changing, adapting to the situation.

  Bill Angel, for instance, seemed to be shedding a lot of the bluff humor that Libet had recognized in him on Earth. He had grown an undisciplined black beard — he didn’t even look like himself any more — and he spent a lot of time bawling out the mission planners and controllers who
, he said, were grinding them all flat with their instructions and demands and routines — or Paula Benacerraf over some chore he’d been assigned that he wasn’t happy with, like the work on the balky SCWO waste-reduction reactor which still wasn’t functioning as it should…

  All this bull just washed over Libet. Angel was a pilot with nothing to do, just spinning his wheels. He was just finding ways to cope with his situation. Likewise Rosenberg, with his endless, obscure chains of experiments. Ways to cope.

  But with Nicola it was different. Nicola didn’t seem to be finding the inner resources to handle this. She didn’t find anything a comfort any more: the work they did, the entertainment materials they’d brought along.

  But at least they had each other.

  It had taken the two of them a month to work up the courage — and to get over their space adaptation syndrome — but now Libet and Mott were regularly spending their sleep times in each other’s quarters.

  It was a small ship, and the rest weren’t stupid. She’d intercepted one or two quizzical smiles from Benacerraf, exasperated glares from Bill Angel. Only Rosenberg seemed too sunk in his own world to figure it out.

  Sharing quarters designed for one person was pretty cramped, but that was okay for Libet; she seemed to find the closeness of another human body — the warm smoothness of Niki’s skin against hers — a great comfort.

  Like the farm, maybe: elemental human contact, as a barrier against the huge searing dark outside.

  A farm this size needed around sixteen hours work a day: planting, harvesting, wheat grinding, preventative maintenance, adjusting the nutrient solution. So that was work for two people, every day.

  Libet did more than her fair share. But then, this was her favorite place in the spacecraft cluster.

  She hadn’t expected to react like this, to hanker after growing things. She was a city girl. And after all she’d spent months in low Earth orbit, on Station.

  But there, right outside every window of Station, had been Earth itself. Here on Discovery, between planets, Earth had been taken away. The only object that showed as more than a point of light — anywhere in three-dimensional space all around the orbiter — was the sun, huge and bright.

  Oh, Venus was approaching; in a month or so they would make their first pass past the planet, for the first of the two fuel-saving gravity assists. It would be spectacular. But Venus was just a big white featureless billiard ball, hot and hostile and hidden. Venus didn’t count.

  The orbiter was like an isolated island, suspended in blackness. And she missed Earth. She missed having that huge sky-bright skin below the craft all the time, complex and dazzling, throwing soft, diffuse light into the cabins. She missed having home so close. She was, she was realizing belatedly, a true creature of Earth; she just wasn’t designed to be out here, in all this emptiness, with only the hard, pitiless light of the sun around her.

  And so she spent as much time as she could afford here, in this little bubble of light and life, ignoring the huge dark beyond the walls.

  Angel pushed buttons to open up the protective doors over the various solar telescopes. The cameras provided images of the sun at a variety of wavelengths, each generated by a different temperature, and so corresponding to a different depth in the star. In the H-alpha wavelength the sun was a fat, roiling sphere of white gas, peppered with black specks that churned, slowly and grandly, like some huge bowl of boiling oatmeal. In the extreme ultraviolet, the sun was a disc of irregular patches of color, without pattern or meaning he could detect. And in X-ray the sun was a fantastic landscape of blue, black and orange, showing up the areas of greatest activity and heat.

  As soon as he brought up the X-ray image he could see what the problem was.

  There was a big fat dark blue patch, like a bruise, right in the middle of the sun’s disc. That was a coronal hole, a part of the solar surface where the corona — the sun’s outer atmosphere — was less dense. Magnetic field lines could sprout vertically out into space, gushing out heavy particles at twice the normal velocities, like a hose. And that powerful jet was slamming into the slower-moving solar wind that lay between the sun and the spacecraft, churning it up into vast disturbances with tangled magnetic fields.

  And all that shit was coming down on Discovery.

  Angel hit the master alarm. The hab module was filled with a loud, oscillating tone, and four big red push-button alarm lights lit up on the instrument panels around the cabin.

  A second later the automatic flare alarm joined in, triggered by the radiation pumping against the hull of the ship.

  Benacerraf came stumbling out of her quarters. She was in her underwear, and Angel could see the curves of her small, blue-veined breasts. Her hair was stuck to the side of her face, and her eyes were huge.

  Angel hit a button to kill the alarms.

  “What? What is it?”

  “SPE,” he said. Solar proton event: a solar storm. “We got to get everyone in here.”

  “Rosenberg is supposed to be asleep, and Nicola is in the centrifuge.” She looked about. “Siobhan must be in the farm—”

  “She’ll be safe if she stays in there,” Angel barked. “You bring Nicola in. I’ll talk to Siobhan, make sure she stays put for a few hours.”

  As he snapped out the orders, he felt exultant. At last, they were going to see some action; at last, after these months of dullness, he could do something.

  Angel tried the squawk box, but got no reply from Libet. So he went back to the science station to try to get more data on the SPE.

  Soon, four of them were here: Angel, Benacerraf, hastily dressing, Rosenberg looking sleepy and confused, and Nicola Mott, still sweating from her time in the centrifuge.

  Angel found his gaze wandering over Mott’s body, what he could see of it inside her shapeless Beta-cloth clothes. She was sunk in on herself, but she was cute as hell, dyke or not. It would be interesting to make her sweat some other way, he thought.

  “How come those assholes on the ground didn’t warn us about this?”

  Benacerraf shrugged. “They probably didn’t know themselves. We’re a lot closer in than they are; the storm may not have reached them yet.”

  He tried the squawk box again. “Damn it. I still haven’t spoken to Siobhan.”

  Mott looked horrified. “Then she mightn’t know what’s going on. Maybe I should go find her. You know what she’s like. She spends hours in that farm with her earplugs in—”

  Benacerraf said, hesitant, “The access tunnel isn’t shielded. Wait until the storm passes. Anyhow, even if she has her plugs in she should see the alarm lights.”

  Mott frowned, and started to chew at her fingernail, industriously.

  Angel tried the squawk box again; there was no reply. “Ah, the hell with it. If there’s nothing you can do, make the best. Right? I’m hungry. Who wants to eat? Paula, who’s on chow detail?”

  Rosenberg sounded disgusted. “I’m going back to bed. You asshole, Bill.”

  The women turned away from him. Benacerraf said, “Keep trying Siobhan, Bill.”

  Chicken-livered dykes,he thought.

  He turned once more to the X-ray image in the monitor, and watched the grey-black coronal hole work its way across the boiling surface of the sun.

  When her work was done, Libet stowed away her tools and cleaned her hands with disinfected wet-wipes. She was due for her daily four hours in the centrifuge; her legs seemed to ache in anticipatory protest.

  She stripped off her coverall and hat, and stowed them away. She opened the hatch to the connecting tunnel which would take her back to the hab module. The tunnel, a few yards long, was light, flexible.

  Unshielded.

  She had to dog closed the hatch behind her. The hatch was heavy and tended to stick, and had taken some shifting; by the time she had it closed she was tired and felt ready to rest, briefly, in the tunnel.

  She let herself drift in the air, and she could feel her relaxing muscles pulling her into the usual ne
utral-G foetal position.

  She closed her eyes. After the breezy farm, the tunnel was cool and still and comfortable. Maybe she could nap for a few minutes; it wouldn’t do any harm.

  A line of light streaked across her vision, a tiny meteor against the dark sky of her closed eyelids.

  In the farm module, unnoticed, a red lamp was blinking.

  There were no alarms in the access tunnel.

  Benacerraf drifted in her sleeping bag, her reading light on, listening on the squawk box to the reports from JSC.

  Solar plasma was buffeting the Earth’s magnetic field, making it shudder, and huge electric currents were surging around the upper atmosphere.

  The power grid serving the Canadian province of Alberta had gone down. In Britain, the northern lights were visible as far south as London. The Global Positioning System was breaking down; navigational fixes from the GPS satellites were unreliable because of the changing properties of the atmosphere. The Chinese had lost Echostar 3, a communications satellite. The energetic electrons racing around the Earth had caused a build-up of charge; a spark had generated a fake command to turn Echostar’s solar panels away from the sun. After a couple of hours, its batteries ran down, and it was lost. The energy of the storm was also heating up the outer atmosphere, making it expand; satellites as high as two or three hundred miles were experiencing a twenty-fold increase in atmospheric drag…

  She fretted about Siobhan. But there wasn’t a damn thing she could do until the storm passed.

  Discovery was designed to shield them from the radiation hazards of deep space — hazards from which Earth’s magnetosphere and thick layer of atmosphere sheltered the rest of mankind.