Gershon laughed. “Who’s playing me? And which one of us is the alien?”

Haise, good-hearted but no public speaker, read on. After a couple of minutes, Stone found he was able to tune out the halting voice from his awareness.

The news was important, though, he figured. It reminded them all that there was still a whole world back home, something more to go back to than the confines of these cans they were stuck inside.

Stone took a leak, washed, and pulled on a T-shirt and shorts. He suspended a pair of reading glasses around his neck on a string.

Actually today should be a good day. The mission plan said that Stone had some optical tracking work to complete in advance of the TCM-2, tomorrow’s course correction maneuver. It was a mission highlight he’d been looking forward to since the flight plan had been drawn up.

But he had a lot of crap to get through first. [Hr:Min:Sec] 08:15:31

After the usual slow, messy breakfast, the crew’s first task of the day was to swab down the walls of the Mission Module with disinfectant wipes.

This had to be done every couple of weeks — more often sometimes, if the boffins on the ground told them that bacterial activity in the Mission Module was becoming unacceptably high. It was a microgravity problem. Microorganisms tended to flourish on free-floating water droplets, and they collected in odd corners of the module. On top of that, microgravity lowered the crew’s immune response: something to do with reduced numbers of lymphocytes in the blood.

After that, the three crew drifted to the Space Ark.

The ark was a collection of cute-animal experiments, some suggested by high-school kids. There were plastic cages of varying sizes, bearing minnows, six mice, a few hundred fly pupae, and a spider called Arabella. There was even a box of worms. Stone tapped a Perspex wall; he could see that the minnows were swimming about in tight circles, evidently disoriented by the lack of gravity.

During mission planning York had been earnestly skeptical about the validity of the ark’s science, and Gershon had flatly refused to have anything to do with such crap. But Stone noticed that both of them were drawn to the little kit.

Stone found the worms interesting. They were called palolo, from Samoa. They lived in tunnels gnawed deep into coral reefs, and they timed their emergence, to mate, by the last quarter of the October Moon. Every year. But nobody knew how the worms did this. At Samoa, the tides, linked to the Moon, were too small to be noticed by the worms. And moonlight could hardly penetrate more than an inch or two into the worms’ rocky burrows.

So this experiment was to find out what would happen to the worms when they were no longer in Earth’s gravity field.

Meanwhile, the spider was contained in a shallow box, labeled Araneus diadematus A healthy web, at least a foot across, spanned the box, with the spider plucking at its heart.

“Okay, Arabella,” Stone murmured, “so you’re an astronaut now, eh? Let’s see how smart you really are.” He moved the front of the box, and the web’s longerons were ripped; the web rapidly imploded, leaving the spider drifting. He felt obscurely cruel in wrecking the web. But the point of the experiment was to record fresh web-building. There were acoustic transducers which set up a high-frequency sound field in the cage; any movement of the spider would disturb the sound and trigger lights and a still camera.

The three crew clustered around the little box, making wisecracks about the spider and poking at the cage and its equipment.

Stone moved over to a small experimental garden. It was more like a window box, a tray of soil the size of a suitcase. There were peas, wheat, cucumbers, parsley, onions, dill, fennel, and garlic. Some of the plants were growing in pure microgravity and some in a small botanic centrifuge, simulating lunar and Martian conditions.

Stone tended the rows of little plants. The peas had grown well for the first four or five weeks, but now they looked as if they were dying, and he fed them water and nutrient carefully. The plants wouldn’t consistently go to seed, but tests had shown that the food value of the plants was high; microgravity didn’t impair protein synthesis. Their roots straggled, though, unable to orient themselves without gravity.

Stone was struck by the contrast of the warm, green, fertile little plants and the cold blackness a few inches away, beyond the wall of the Mission Module. He breathed on the little pea plants, hoping to provide a richer mix of carbon dioxide for them. [Hr:Min:Sec] 09:57:57

Stone hauled at the isokinetic exerciser. The machine was bolted to a bracket in the middle of the Mission Module, and it had a two-handled lever, with shoulder pads and handgrips, linked by a sprocket chain to an air turbine. The exerciser was a newfangled gadget, to replace the treadmills and rowers that had been carried on earlier flights. By bracing himself on a foot platform, Stone could do squats, toe raises, shoulder presses, high pulls, bench presses, tricep presses.

Every so often he would glance at the machine’s timer and get newly depressed at how much more time he had to spend exercising. He was uncomfortable, his vest soaked, pools of sweat clinging to his chest and between his shoulder blades. His only distraction was a small round observation port, set in the pressure hull near him, and he stared into its darkness.

After a couple of months — the way Stone understood it — the various functions of the body adapted to microgravity, settling down to a new equilibrium, different from that on Earth. The neurovestibular system, the balance mechanism within the ear, was the first to fall apart — hence, space sickness — but also the first to recover, after a few days. The body’s fluid balance would adjust then, and next the cardiovascular system, the heart and blood vessels.

But things didn’t go back to Earth-normal.

Stone’s brain, which didn’t know about microgravity, thought that all that extra blood was pooling in his head because there was too much fluid in his body, and it told his kidneys to release more urine. And that way lay dehydration. So Stone had to drink an extra five pints of fluid a day, laced with water-salt imbalance counteragents. That was something NASA had learned from the Russians.

But all the extra pissing flushed the calcium and potassium out of his bones. The calcium deficit could make his bones brittle, or give him kidney stones, and the potassium could leave him prone to heart problems; so he had to take dietary supplements, and there were anabolic steroids in case any of them suffered severe bone loss.

His muscles didn’t do any work they didn’t have to, and — if he left them alone — they would atrophy. So he had to go through all the exercise on the isokinetic device. There were other measures, too, like the penguin suit — so-called because it made you waddle around on the ground during training — a set of elastic straps that tried to pull you into a fetal position all the time, so your muscles were constantly working, as if against gravity. And there was the chibis, a Russian word for lapwing bird, another idea borrowed from the Soviets: reinforced leggings that reduced the air pressure over the legs, to make the heart work harder to pull blood up from the lower body.

The isokinetic exercises ought to help with reducing bone mineral loss, too; bones always kept themselves just strong enough to resist the maximum loads imposed by the muscles.

The crew had to submit, every two or three days, to electrocardiograms, seismocardiograms, measurements of their breathing rates and volume. All of it was fed back to the surgeons on Earth. All the biomed stuff added up to a whole day lost out of every week.

None of it was popular. Stone realized, though, that it was up to him to set an example to the others. If he skimped, so would they. So he made sure he did at least his regulation hour’s exercise, every day.