Bleeker frowned.

“Free radicals are bits of molecules. Highly energetic. Like ions — with charges knocked out of their atoms — only with more horsepower. They’re highly oxidizing, which means they have a taste for hydrogen. They’ll strip hydrogen atoms out of nearby molecules, even. And that can cause havoc if it’s happening inside your cells.

“Now, we’ve all got free radicals in our bodies. We need them for the operation of the metabolism. But there’s a balance. Your body produces them, and absorbs them, and keeps everything together. But if you’re exposed to high-energy radiation, or light, or extremes of temperatures—”

“You get more free radicals.”

“Right. The balance is lost.” Muldoon looked over the report once more. “These babies propagate. A free radical will return to normal by stealing its neighbor’s electron. But that makes that neighbor into a free radical in turn. Your body has a scavenger system to fight these things, but it can get overwhelmed or inactivated. And then the damage you suffer depends on what gets hit. You can get radiation-induced cancers if a DNA base is damaged, or your system loses control of its functions if protein is damaged, or you can get internal bleeding if membrane lipids are broken.”

Bleeker frowned. “Membrane lipids, Joe?”

Muldoon tried to put together an answer in plain English: how free radicals contributed to aging, and cancers, and degenerative diseases of the heart, liver, and lungs; how the loss of free-radical balance contributed to a lot of other microgravity problems like disturbing the inner ear’s balance mechanism, and bone degeneration…

“Look, Adam, you ever left a slab of butter out in the sun?”

Bleeker thought about it. “Gets rancid.”

“Well, there you are. That’s free radical damage.”

Bleeker, his eyes locked on Muldoon’s, started pulling at his cuff, in a precise, apparently unconscious gesture.

Bleeker really did seem to have a kind of inner calm, an even temper. It had evidently gotten him through all that A-war shit he’d trained for, Muldoon supposed. Maybe the psychs were right, that Bleeker had a lack of imagination.

But Muldoon could see the tension building in him, under the surface. How was he going to react to this, the worst news of his life?

“Look, Adam. You have to understand. You’re not ill. It’s just that because of this kind of study, they’ve tightened the limits. On everybody. And you, with all your exposure to space, have finished up outside the limits. If the free-radical study had come in a couple of months earlier you probably would have been bumped off D-prime, too. Look — you might have suffered some of this free-radical damage. Or not. Or something else—”

“I’ve proved myself in space, Joe, and on the ground, time and again. Look how I pulled off the D-prime flight. I deserve this goddamn trip.”

“I know that, but—”

“And I know about surgeons’ reports. They talk about risks. Likelihoods and percentiles. Not certainties. And besides, it isn’t logical. The Ares crew is going to run up a lot more time in space than I’ve accumulated anyhow.”

“But starting from a lower base, Adam. Even Phil Stone.”

“Joe, I don’t care about the risks. I want to go anyhow.”

“If it costs your life?”

“Even so.”

Bleeker lifted up his head, and there were those wide, church-window eyes looking right into Muldoon, open, honest, committed.

I have to kill this, here and now. I can’t leave him with any hope. And he didn’t intend to tell Bleeker about the pressure he’d been under: from the flight surgeons, even from Administrator Josephson himself. He wasn’t going to hide behind any of that.

“That’s not the point, Adam,” he said, and he tried to get some steel into his voice. “I can’t risk having you fall ill, halfway to Mars. I can’t risk sending you. Because you would endanger the mission.”

Bleeker smiled, a small motion of the muscles of his cheeks. Then he stood up, stiffly, still tugging at his cuff. “I appreciate the way you’re handling this, Joe.”

“Oh, God. Don’t be kind to me, for Christ’s sake. Adam, we’ll talk later. You know I need your help now. We haven’t got a lot of time to recover from this. And later — hell, there are still good careers here, on the ground.” He laughed, a little hollowly. “Look at me. You’re still in the team, Adam.”

“Sure. I know my duty, Joe. I’ll do everything I can.”

Goddamn this job. This is the most competent man in the Office, and I have to bump him. “Yeah. I know you will.”

Bleeker turned back. “By the way. Who’s replacing me? You decided yet?”

Joe Muldoon hesitated.

His orderly crew rotation system had gone out of the window, first with Curval bombing out, and on top of that came this bad shit from the surgeons about Adam. He felt an unreasonable anger at the doctors, the managers, the psychologists, all the rest of them who wanted a piece of his decision.

He felt like shocking them all, taking back the responsibility in his own two hands.

He’d already spoken to Phil Stone, the Ares mission commander. Stone had defended Bleeker to the hilt. But when he’d come to accept Bleeker was off the mission, Stone had been surprisingly clear about who he wanted to replace Bleeker.

Well, Joe, you have to pick the best Mission Specialist. The most knowledgeable: more so than Adam, for sure. And the most committed: the one who’s been spending time in the sims, and trailing around trying to train the prime crew, and all of that. And -

What?

And someone who can maybe see things, the mission, in a way old jocks like you and me can’t. A different perspective. Someone who can articulate it better, maybe…

Rookie or not, Phil?

Hell, yes, Joe. Rookie or not.

Muldoon found himself grinning. He knew that the candidate he had in mind had spent a lot of time working with Ralph Gershon, in the MLTV and various sims and survival exercises. But only because they were both outsiders, pushed together by circumstance. Still, they’d proved they could work together, although they would never be bosom buddies. The goddamn shrinks will jump up and down, over having two dipsticks on one flight, with only Phil Stone to keep ’em apart…

So, fuck ’em.

“Yes,” he said to Bleeker. “Yes, I’ve decided. But, Adam—”

“Yeah?”

“She doesn’t know yet.”

Vladimir Viktorenko had his shoes off, and he was sipping at a miniature bottle of minibar malt whiskey. He was in Houston to work on more aspects of the Ares training program. He was listening desultorily to the evening news and wondering what to do with the evening.

The newscaster — a stunningly beautiful young woman — said that the crew for Ares had just been announced.

Viktorenko coughed and dropped the little bottle.

He sat up, wiping a fine spray of the liquor from his upper lip. He couldn’t have heard correctly.

But no: there was a picture of Natalie herself, an official portrait in which she sat before a nondescript background, staring past the photographer’s shoulder, nervously clutching a long-obsolete model of a biconic MEM.

He picked up the phone and dialed York.

“Marushka! I just heard! You are going to Mars!”

York’s voice was flat, unemotional. “It isn’t true.”

“What? But I have seen the news…”

“Yeah. Me, too. But I haven’t heard anything from NASA. Until they call me, I don’t know anything about it.”

Viktorenko felt his mouth opening and closing, like a fish’s. You are going to Mars! You should be dancing, singing! The silence on the line stretched out.

“Marushka. You are alone?”

“Uh-huh.”

Of course you are. “Do I have your permission to come wait with you, until the phone call comes? Perhaps this will help you.”