Every day aboard ISS was tightly scheduled, with little time to spare for reflection or grief. If a member was incapacitated, the others had to pick up the slack, or experiments went untended.

“Sometimes,” said Diana with crisp logic, “work is the best thing to keep grief at bay.” He touched his finger to the blur of light that was Tokyo.

“Don’t pretend to have a heart, Diana. It doesn’t fool anyone.” For a moment she said nothing. He heard only the continuous background hum of the space station, a sound he’d grown so accustomed to he was scarcely aware of it now.

She said, unruffled, “I do understand you’re having a hard time. I know it’s not easy to be trapped up here, with no way to get home. But there’s nothing you can do about it. You just have to wait for the shuttle.”

He gave a bitter laugh. “Why wait? When I could be home in four hours.”

“Come on, Bill. Get serious.”

“I am serious. I should just get in the CRV and go.”

“Leaving us with no lifeboat? You’re not thinking straight.” She paused.

“You know, you might feel better with some medication. Just to help you get through this period.”

He turned to face her, all his pain, all his grief, giving way to rage. “Take a pill and cure everything, is that it?”

“It could help. Bill, I just need to know you won’t do something irrational.”

“Fuck you, Diana.” He pushed off from the cupola and floated past her, toward the lab hatchway.

“Bill!”

“As you so kindly pointed out, I’ve got work to do.”

“I told you, we can divide up your duties. If you’re not feeling up to it—”

“I’ll do my own goddamn work!” He drifted into the U.S. Lab. He was relieved she didn’t follow him. Glancing back, he saw her float toward the habitation module, no doubt to check the status of the Crew Return Vehicle.

Capable of evacuating all six astronauts, the CRV was their only home should a catastrophe befall the station. He had spooked her with his mutterings about hijacking the CRV, and he regretted it.

Now she’d be watching him for signs of emotional meltdown.

It was painful enough to be trapped in this glorified sardine can two hundred twenty miles above earth. To also be watched with suspicion made the ordeal worse. He might be desperate to go home, but he was not unstable. All those years of training, the psychological screening tests, had confused the fact Bill Haning was a professional—certainly not a man who’d ever endanger his colleagues.

Propelling himself with a practiced push-off from one wall, he floated across the lab module to his workstation. There he checked the latest batch of E-mail. Diana was right about one thing, Work would distract him from thoughts of Debbie.

Most of the E-mail had come from NASA’s Ames Biological Research Center in California, and the messages were routine requests for data confirmation. Many of the experiments were monitored from the ground, and scientists sometimes questioned the data they received. He scrolled down the messages, grimacing at yet another request for astronaut urine and feces samples. He kept scrolling, and paused at a new message.

This one was different. It did not come from Ames, but from a private-sector payload operations center. Private industry paid a number of experiments aboard the station, and he often received E-mail from scientists outside NASA. This message was from SeaScience in La Jolla, California.

Another jiggle-the-handle request, he thought wearily. Many of the orbital experiments were controlled by commands from scientists on the ground. Data was recorded within the various lab racks, using video or automatic sampling devices, and the results downlinked directly to researchers on earth. With all the sophisticated equipment aboard ISS, there were bound to be glitches. That’s the real reason humans were needed up here—to troubleshoot the temperamental electronics.

He called up the file for CCU#23 on the payloads computer and reviewed the protocol. The cells in the culture were Archaeons, bacterialike marine organisms collected from deep-sea thermal vents.

They were harmless to humans.

He floated across the lab to the cell culture unit and slipped his stockinged feet into the holding stirrups to maintain his position. The unit was a box-shaped device with its own fluidhandling and delivery system to continuously perfuse two dozen cell cultures and tissue specimens. Most of the experiments were completely self-contained and without need of human intervention.

In his four weeks aboard ISS, Bill had only once laid eyes on the tube 23.

He pulled open the cell specimen chamber tray. Inside were twenty-four culture tubes arrayed around the periphery of the unit.

He identified #23 and removed it from the tray.

At once he was alarmed. The cap appeared to be bulging out, as though under pressure. Instead of a slightly turbid liquid, was what he’d expected to see, the contents was a vivid blue-green.

He tipped the tube upside down, and the culture did not shift. It was no longer liquid, but thickly viscous.

He calibrated the micro mass measurement device and slipped the tube into the specimen slot. A moment later, the data on the screen.

Something is very wrong, he thought. There has been some sort of contamination. Either the original sample of cells was not pure, another organism has found its way into the tube and has destroyed the primary culture.

He typed out his response to Dr. Koenig.

What if #23 was not contaminated? What if this was simply how Archaeons behaved without gravity to keep them in check?

Almost immediately he discarded that notion. These changes were too drastic. Weightlessness alone could not have turned a single-celled organism into this startling green mass.

He typed,

The sudden clang of a drawer startled him. He turned and saw Kenichi Hirai working at his own research rack. How long had he been there? The man had drifted so quietly into the lab Bill had even known he’d entered. In a world where there is no up or down, where the sound of footsteps is never heard, a verbal greeting is sometimes the only way to alert others to your presence.

Noticing Bill’s glance, Kenichi merely nodded in greeting and continued with his work. The man’s silence irritated Bill. He was like the station’s resident ghost, creeping around without a word, startling everyone. Bill knew it was because Kenichi was insecure about his English and, to avoid humiliation, chose to converse little if at all. Still, the man could at least call out “hello” when he entered a module to avoid rattling the nerves of his five colleagues.