Titan (35 page)

Then there was a whole series of modifications. They had adapted a hab module—intended as part of a frequent-resupply low Earth orbit station—to serve as the core of a many-year deep space mission. They had reconfigured the systems to take power from a couple of reconditioned Topaz fission reactors, for instance. And they had restructured the module to put shielding material around the hull, like water tanks. It was a lot of work; the engineers had to redesign and rebuild on the fly.

But for Benacerraf it had been a kind of relief, after a decade of frustration. So much fine work had been done on the Station components, only for them to be left standing around in assembly facilities. She had been involved right back when they put together the external structure of the first lab module, back in 1995. Three thousand one hundred inches of weld, all of exceptional quality. You couldn’t buy quality like that. You had to earn it. It was good to see this fine work put to use.

When she was done she made her way to the personal hygiene station, where she washed her hands, face, armpits and crotch with a sponge. The sponge, and the excess water she shook off, she stored so that her hygiene water could be reclaimed.

At the little galley, she prepared a quick breakfast: pre-cooked apple sauce, rehydratable granola, beef jerky and breakfast roll; and to drink, chocolate instant breakfast and an orange-grapefruit squash. She had to put the granola bag into a little tray, which slid into a slot in the galley wall to inject the bag with water. She piled the food up on a tray, sticking it down with Velcro pads.

She ate in a kind of Japanese style, with the food close to her face, and she spooned it into her mouth in smooth, graceful arcs. She worked with care. If she jerked the spoon, the glob of food would just fly off, and end up on her face, in her hair, on the walls. And when she sipped her drink, she took care to blow the excess liquid back into the container, or it would come slithering out of the straw and go floating around the module.

She didn’t feel hungry, but she made herself finish the food. Suppressed appetite was some artifact of microgravity, an illusion. She tried to add salt and pepper to give a little flavor to the meal. But the diluted salt tended to clog the nozzle of its dispenser. Once Angel, frustrated, had squeezed the dispenser so hard it burst, and they spent two days picking salt off the walls of the hab module. And the pepper, in traditional particle form, just floated off around the hab module rather than settle on the food. The crew had anticipated this and had brought along a lot of spices and condiments, like horseradish and soy sauce and Tabasco sauce. But already these were becoming depleted, and they were trying to ration themselves…

She let herself drift in the air as she ate, her eyes unfocused. She felt herself relax into what the surgeons called the “neutral G” position, with her legs pulled up a little, her shoulders bent into a crouch, and her elbows bent. She was floating like a fetus, in the warm blue womblike interior of this hab module.

Right now they were still living off Shuttle-class consumables, but they would be replaced by produce from the CELSS farm as soon as was practicable. Already, their waste was being stored, and would be cycled through the hydroponic farm, so as to close the matter loops of their life support system.

But they would still have to supplement their diet with stored food—this disgusting beef jerky, for instance—to acquire amino acids and other substances not available from the farm’s vegetables.

When she was done, she rinsed off her tray in the housekeeping and laundry area. The water she used was sucked away by a vacuum pump, for further recycling.

It was Benacerraf’s day for fresh clothes. She went to her personal locker in the wardroom area. She pulled out her underwear drawer. The clothing did the usual zero-G jack-in-the-box trick, bursting out of the drawer and into the air around her face. It took her a couple of minutes to stuff it all back in the drawer and strap it down, picking out items to wear today. Then she opened her main clothing drawer and picked out a T-shirt and trousers.

She went back to her quarters.

She stripped naked and examined herself briefly, with the help of the little mirror of polished aluminum on the wall. Her face had become puffy, especially around the eyes. The girth of her waist and chest had increased. The blood was pooling in her chest, where it restricted the capacity of her lungs, and in her back, where it was absorbed by the spongy discs between her vertebrae, making them thicker and pushing the vertebrae apart. As a result she was an inch or two taller than she had been on Earth.

She inspected her legs with some interest. Legs were pretty much useless in space, serving only to bump into obstacles. And after eighty days, her legs—skinny, pale chicken legs, drained of fluid—were covered with bruises and cuts, in various stages of healing. But she was getting better. Actually she rarely moved faster than a couple of feet per second; she found it was more productive, in microgravity, to aim for precision rather than speed.

She got dressed.

The clothes were dull: T-shirts, jackets and trousers made of golden-brown Beta-cloth—selected because it was fireproof—with 1970s-style turtlenecks and elasticated cuffs. The others griped about the dull, scratchy clothes, but Benacerraf didn’t mind. These designs actually went back to Skylab; the clothes were tough, would stand repeated washing, and they were available, just lying around in a store at JSC.

Getting dressed was always an unexpected struggle. The clothing tended to wriggle away from her. She had to work her stomach muscles to drag her feet up close to her chest to pull on a sock or a shoe, and when she’d finished it always felt as if she had given those muscles a tough workout.

The gold-brown outfits were fitted with pockets all over, along both sleeves and legs; and in them she stowed everything she was likely to need during the day—flashlight, pad, pencils, Swiss Army knife, scissors. She popped the pockets shut methodically; it she didn’t, the smaller items were likely just to drift out.

She emerged from her quarters and stuffed her used clothes into the laundry bag.

Her most important daily task was to check the status of the life support systems. So she made her way to the control panel.

Every year, a healthy human would consume three times her body mass in food, four times in oxygen, and eight times in drinking water; and would, besides, excrete the same mass in urine, feces, carbon dioxide and water from respiration and perspiration. The only way
Discovery
could sustain a six-year mission to Titan was by closing as many of its mass loops as possible, to support the slow-burning human metabolisms it shielded, to clean up and feed back waste products.

In a way,
Discovery
constituted the ultimate life support technology testbed.

Benacerraf started with the water management system. Their urine, pretreated with acid, had its water distilled out, reducing the urine to a gooey solid. The water was treated with ozone and charcoal filters before being used again, and anyway went into the hygiene supply first, rather than coming straight back to the drinking water. The still had to be rotated to enable phase separation in microgravity, and the rotation tended to disrupt any experiments requiring stability the crew attempted. And every so often the evaporator had to be evacuated and cleaned out, and the fluids pump replaced. A delightful job. Right now, however, the still seemed to be functioning well.

Waste water from other sources—hygiene, the laundry and the air condensate—was cleaned up by a series of filters and packed columns of activated charcoal and resin beds. The filter beds had to be replaced periodically. Then there was a biocide injection system, and a series of automated systems that monitored the quality of the water—for acidity, ammonia, organic carbon content, electrical conductivity, microbial concentration, color, odor, foaming, and heavy metal concentrations—before it was returned to its stainless steel tanks…

She looked over the air management system. The steps here had to mimic some of the processes of life on Earth: carbon dioxide had to be removed and reduced from stale air; oxygen had to be generated, and trace contaminants monitored and removed.

The carbon dioxide was removed by passing the air over filter beds containing solid amines, steam-heated. A Sabatier reactor combined the extracted carbon dioxide with hydrogen, to produce methane and water. The Sabatier was a nice reliable design which needed hardly any maintenance. Oxygen was produced from the water by electrolysis, a process she remembered from her own high school days, where an electric cell broke up the water molecules into hydrogen and oxygen. The oxygen fed back into the air supply, and the hydrogen was passed back to the Sabatier reactor. The electrolysis technology was so simple and mature that there was hardly anything which could go wrong with it.

Carbon dioxide in; oxygen out. It was a neat, robust system.

The trace contaminant control was built into the ventilation. A lot of crap could build up quickly in the closed cycles of the hab module. So there were particulate beds to separate dusts and aerosols, activated charcoal to keep out heavier contaminants, chemisorbant beds to remove nitrogen, sulphur compounds, halogens and metal hybrids, and catalytic burners to oxidize anything that couldn’t be absorbed.

She checked through a few more ancillary systems: composition and pressure control, the heat exchanger slurper that controlled temperature and humidity… The whole system was monitored and controlled in real time by a complex of sensors, including a mass spectrometer and infrared detectors.

She checked the SCWO reactor, the supercritical wet oxidation system. The SCWO was a remarkable piece of gear. Inside, slurry was heated to four hundred and eighty degrees Centigrade and two hundred and forty atmospheres, conditions where water went supercritical. It was like liquid steam. If you jetted in oxygen, you could get an open flame, under water. The SCWO would burn anything, any waste they threw into it: crap, urine, food scraps, garbage, mixed up with organic wastes and water. Out came steam, carbon dioxide, and a whole bunch of nitrates—compounds of nitrogen they could use in the farm.

It looked to Benacerraf as if the temperature control inside the reactor had been a little variable. That was a worry; not everything that happened inside that reactor was well understood. The SCWO was a relatively new technology—the reactor and its backup fitted in
Discovery
were actually upgrades of breadboard prototypes. There were safety concerns around the high temperatures and pressures in the reactor, and corrosion of the pressure chamber. That corrosion could leak metals into the liquid effluent, which could then end up in the food chain.

In a way she was relieved to find something wrong. It proved the monitoring systems were working, and that she was maintaining her own attention as she worked through this daily inspection routine. Bill Angel was on SCWO duty this week. Good; Bill was mechanically adept, and might be able to do something with the malfunctioning reactor. She made a note, and moved on to the next system…

Thus, with this string of clanking and banging mechanical gadgets of varying sophistication and reliability, with a stream of endless small details, the crew of
Discovery
sustained the stuff of their existence.

Her last chore, before starting the day proper, was to check the vent grilles, the dark screens that led to the air conditioning system. Not being able to put things down and find them again was the single biggest handicap, as far as she was concerned, about living in microgravity. If you let some small item drift off, you really had no clue as to which direction it might have taken, and you just had to be patient and wait the couple of hours it usually took for items to fetch up against the grille.

Today she found a syringe, a one-inch bolt, a couple of small bags, a rule, and several scraps of paper She had a system for this; she saved the stuff that looked useful in one pocket, and the detritus in another.

She tried to get a little science done.

There was a telescope mount, equipped with lightweight cameras for observing the sun at a variety of wavelengths: hydrogen alpha emissions from the sun’s surface, ultraviolet and X-ray photography of ionized atoms, solar corona and flare imaging systems. No human crew had ever before ventured so close to the sun, nor would again for a hell of a long time.

But the science was hardly high quality. The equipment in the telescope mount had been improvised from left-over spare parts from unmanned missions, like
Soho
and
Ulysses.
And besides,
Discovery
wasn’t a good science platform. The camera tracking gear had to compensate for the spacecraft’s slow barbecue-mode rotation. And
Discovery
was just too unstable, with five humans, hundred-and-fifty-pound water sacks, lurching massively around its interior. It was G-jitter, in the jargon, sometimes amounting to five or ten percent of G. Even a cough would exert fifteen or twenty pounds of force, and a squirt on a water spigot would jar the cluster enough to jolt the crosshairs of a camera from the center of the sun. And of course the use of the centrifuge shook the whole cluster around so much it made any kind of sensible experiment more or less impossible.

Meanwhile the crew themselves were the subject of endless experimental studies; the bodies of the crew of
Discovery
would, she knew, write the textbook for the next few decades on the long-term effects of space travel on human physiology. But the studies were distorted by the fact that the crew were doing their utmost, with varying degrees of enthusiasm, to combat the effects of microgravity, radiation and the other hazards of the flight. If the studies had been true science, she reflected, you’d have some kind of control: one crew member who didn’t take any exercise or other precautions at all, for instance.

There were rumors that the Chinese, in the course of their expanding space program, were doing just that. But for Americans, of course, that was just unacceptable.