“Dangerous bugs like that on the station? That would be a serious problem.”

“Exactly. Especially in a closed environment like ours. We’d all be vulnerable.”

“What about autopsying the dead mice?”

Emma hesitated. “We’re only set up to deal with Level Two contamination up here. Nothing more dangerous. If this is a pathogen, I can’t afford to risk infecting other animals. Or people.”

There was a silence. Then Loomis said, “I understand. And I guess I have to agree with you. So you’ll be safely disposing of the corpses?”

“Immediately,” said Emma.

For the first time since he’d arrived on ISS, Kenichi could not sleep. He had zipped himself into his restraint bag hours ago, but he was still awake, still mulling over the puzzle of the dead mice.

Though no one had uttered a word of reproach, somehow he felt responsible for the failed experiment. He tried to think of what might have done wrong. Had he used a contaminated needle, perhaps, when he’d sampled their blood, or a bad setting in the rack’s environmental controls? Thoughts of all the possible mistakes he might have made kept sleep at bay.

Also, his head was throbbing.

He had first noticed the discomfort this morning, when it had started as a vague tingling around his eye. As the day wore on, tingling had become an ache, and now the left half of his head hurt. Not an excruciating pain, just a nagging annoyance.

He unzipped his bag. He was getting no rest in any event, he might as well check on the mice again.

He floated past Nicolai’s curtained sleep station and headed through the series of connecting modules that led to the U.S. of the station. Only when he’d entered the lab did he realize someone else was awake.

Voices murmured in the adjoining NASDA lab. Silently he floated into Node 2 and peered through the open hatch. He saw Diana Estes and Michael Griggs, limbs tangled together, mouths locked in hungry exploration. At once he backed out unnoticed, face burning with embarrassment at what he’d just witnessed.

Now what? Should he grant them their privacy and return to his sleep station? This is not right, he thought with sudden resentment. I am here to work, to fulfill my duties.

He floated to the animal habitat. Deliberately he made a great deal of noise as he opened and closed the rack drawers. A moment later, as he’d expected, Diana and Griggs suddenly appeared, of them looking flushed.

And well they should be, he thought, considering what they’ve been up to.

“We had a problem with the centrifuge,” lied Diana. “I think it’s fixed now.” Kenichi merely nodded, betraying no sign that he knew the truth.

Diana was cool as ice about it, and that both appalled and angered him.

Griggs, at least, had the decency to look a little guilty.

Kenichi watched as they floated out of the lab and disappeared through the hatch. Then he turned his attention back to the animal habitat. He peered into the cage.

Another mouse was dead. A female.

August 1

Diana Estes calmly held out her arm for the tourniquet and squeezed her hand open and shut several times to plump up her antecubital vein. She did not flinch or look away as the needle pierced her skin, indeed, Diana was so detached, she might have been watching someone else’s blood being drawn. Every astronaut was poked and prodded many times during the course of his or her career. At selection screening, they endured multiple blood draws and physical exams and the most probing of questions. Their serum chemistries and EKGS and cell counts were on permanent record, to be pored over by aerospace physiologists. They panted and sweated on treadmills with electrodes attached to their chests, body fluids were cultured, their bowels probed, every inch of skin was examined. Astronauts were not just highly trained personnel, they were also experimental subjects. They were the equivalent of lab rats, and while in orbit, they resigned themselves to a sometimes painful battery of tests.

Today was specimen collection day. As the physician on board, Emma was the one wielding the needles and syringes. No wonder most of her crewmates groaned when they saw her coming.

Diana, though, had simply held out her arm and submitted to the needle.

As Emma waited for the syringe to fill with blood, sensed the other woman’s gaze appraising her skill and technique.

If Princess Diana had been England’s rose, went the joke at JSC, then Diana Estes was England’s ice cube, an astronaut whose poise never cracked, even in the heat of real calamity.

Four years ago, Diana had been aboard Atlantis when a main engine failed. On tapes of the crew transmissions, the voices of shuttle commander and pilot had risen in alarm as they scrambled to guide the shuttle in a transatlantic abort. But not Diana’s voice.

She could be heard coolly reading the checklist as Atlantis hurtled to an uncertain landing in North Africa. What had sealed her icy reputation were the biotelemetry readings. On that particular launch, the entire crew had been wired to record their blood pressure and pulse. While the heart rates of everyone else had skyrocketed, Diana’s had barely accelerated to a leisurely ninety-six per minute. “That’s because she’s not human,” Jack had joked. “She’s really an android. The first in NASA’s newest line of astronauts.” Emma had to admit there was something not quite human about the woman.

Diana glanced at the puncture site on her arm, saw that the bleeding had stopped, and matter-of-factly turned back to her protein crystal growth experiments. She was indeed almost android perfect, long-limbed and slender, her flawless skin paled to white from a month in space. All that plus a genius IQ, according to Jack, who had trained with Diana for the shuttle mission he had never completed.

Diana had a doctorate in materials science and had published over a dozen research papers on zeolites—crystalline materials in petroleum refinement—prior to being accepted into the astronaut program. Now she was the scientist in charge of both organic and inorganic crystals research. On earth, crystal formation was distorted by gravity. In space, crystals grew larger and more elaborate, allowing thorough analysis of their structure. Hundreds of human proteins, from angiotensin to chorionic gonadotropin, were being grown as crystals aboard ISS—vital pharmaceutical research that could lead to the development of new drugs.

Finished with Diana, Emma left the ESA lab and floated into the hab, to find Mike Griggs. “You’re next,” she said.

He groaned and reluctantly held out his arm. “All in the name of science.”

“It’s just one tube this time,” said Emma, tying on the tourniquet.

“We’ve gotten so many needle sticks we look like junkies.” She gave his skin a few gentle slaps to bring out the antecubital vein. It plumped up, blue and cordlike on his muscular arm.

He had been compulsive about staying in condition—not a simple thing while in orbit. Life in space took its toll on the human body.

Astronauts’ faces were bloated, swollen by shifts in fluids, thigh and calf muscles shrank until they had “chicken legs,” out pale and scrawny from their bloomerlike shorts. Duties were exhausting, the irritations too numerous to count. And then there was the emotional toll of being confined for months with crewmates who were under stress, scarcely bathe, and wearing dirty clothes.

Emma swabbed the skin with alcohol and pierced the vein.

Blood shot back into the syringe. She glanced at him and saw his gaze was averted. “Okay?”

“Yeah. I do appreciate a skillful vampire.” She released the tourniquet and heard his sigh of relief when she withdrew the needle. “You can eat breakfast now. I’ve drawn everyone’s blood but Kenichi’s.” She glanced around the hab.