Aftermath (28 page)

She then told them I was a world's leading authority on cloning, a subject that happens to be regarded by the general public with strong suspicion. Finally she emphasized what a genius I was, and showed how my career had been marked since early childhood by an outstanding brilliance.

You could see the wheels working inside jury heads.

Question: "Who do you want out on the streets even less than an insane mass murderer of teenagers?"

Answer: "An outstandingly brilliant and cunning insane mass murderer of teenagers."

I knew at that point what my defense attorney apparently did not: my fate, in spite of or because of her best efforts, was sealed.

19

The lesson had been driven home every day for a thousand days, from pre-mission selection to Earth orbit departure: the first Mars expedition faces more unknowns than anyone can guess. There will be injuries, there may be fatalities. No matter what happens you must regroup and assess your remaining resources; and you must continue.

Continue until you reach Mars; continue to descend to and explore Mars; continue until you return to Earth from Mars.

Celine raised her head and stared around the control room of the
Schiaparelli.
They had held together and worked together. They had overcome every obstacle. They had come so close to success, so agonizingly close; and they had failed.

The other three were ignoring each other, locked into private worlds of grief or guilt. Reza Armani had moved to one of the control chairs. He was working through the command telemetry as it had been received from
Lewis
until the final seconds of radio silence. With its help he was reconstructing every action that Zoe Nash had made, mimicking her exact sequence of movements at the ship's controls. He was muttering to himself, and his features twitched constantly. When the
Lewis
became a cloud of hot gas he appeared to lose touch with reality.

Wilmer Oldfield was also staring blank-eyed at nothing and apparently doing nothing. He had vanished inside his head, to a place beyond Celine's access or imagining. That didn't worry her. Wilmer did that all the time.

She turned to Jenny Kopal. She could understand what Jenny was doing, and sympathize with it. Somehow, the transfer of chips and library programs from the
Schiaparelli
to the
Lewis
had been botched. Since that responsibility was Jenny's, she felt she had killed Zoe, Ludwig, and Alta as directly as if she had driven knives into their hearts. She was poring, white-faced, over displays and transfer protocols.

And Celine's own failure? She knew it now, when it was too late. Zoe had made the decision to return to Earth two days after their arrival at ISS-2. She did so before they knew the extent of the work before them, before the orbiters were fully inspected, before Zoe or anyone else had a rational basis for setting a schedule.

Celine had been deeply worried by the impulsiveness of Zoe's action. But what had she done? Had she pointed out her reservations, knowing that her warning would be listened to and taken seriously—that this Cassandra was never ignored?

No. She had done nothing, overwhelmed by Zoe's personality and confidence and strength of purpose. Or—place the blame where it belonged—overwhelmed by Celine's own desperate longing to be home again on Earth.

She glanced around the cabin again, and found everyone's eyes on her. What now?

"We saw what happened to the
Lewis.
" Celine found herself speaking, in a voice surprisingly level and controlled. "We probably all have our own ideas as to what caused the disaster. At some point we will have to decide what to do about our own return to Earth. But not yet. Right now it is time for a group discussion."

That's right. Speak of the fate of the
Lewis,
rather than of Zoe, Ludwig, and Alta. Keep the discussion as impersonal and unemotional as possible. Don't allow anyone to indulge in breast-beating.

But at the same time a voice inside her was asking other questions:
Why am I doing this? Isn't this a job for someone like Zoe, a natural leader? Why me?

And an answering voice:
Their deaths have changed all of us. Jenny is more human, Wilmer is more alert, and Reza is closer to the borderline between normal and psychotic.

The other three didn't seem to find Celine's assumption of leadership as odd as she did. Jenny was rubbing her eyes, as though she had been secretly weeping, but she said quietly, "I think it is obvious what happened. I downloaded software modules for orbiter control from the program library onto spare chips available on the
Schiaparelli.
I installed those chips in the
Lewis,
replacing dead elements there. I believed that I had done everything correctly. But when Zoe tried to change the orbiter's pitch, the software module gave a command that drove the correction the wrong way. The orbiter was entering the atmosphere more steeply after the correction, instead of less steeply. Drag forces and frictional heating on the
Lewis
increased, rather than decreasing, until temperatures went past hull material limits. If only I had been more careful, and checked—"

"We don't know that's what happened." Celine cut Jenny off smoothly but firmly. "Did you find a software error that could produce an effect like that?"

"No. But I'm still looking. It's the only thing that could possibly—"

"Not proven. We need to hear from everyone before we attempt an analysis." Celine turned away from Jenny. "Reza?"

"Well, we may never know exactly what sequence of actions Zoe took." Reza's voice was higher than usual, but he picked up before Jenny could speak again. "There was no telemetry for the crucial period, because of ionization radio blackout. But the controls of the orbiters are quite a bit different from the controls of the
Schiaparelli
or of the Mars landers."

Speech seemed to have stabilized him, because his voice was more normal when he went on, "I know that, because I've had more practice sessions than anyone except Zoe herself. It would be easy, in the heat of the moment, to invert a control command and increase the angle of attack rather than decreasing it."

"If Zoe had done something like that she would have realized it in a split second," Jenny said. "She would have made the correction. She didn't." Her voice wobbled and rose in pitch. "I tell you, Reza, it's in the software routines."

"We'll discuss software and other possible causes later," Celine said curtly. "I don't want to talk about it now. Wilmer?"

She turned to him, without much hope of hearing anything useful. It wasn't clear that he had even been listening. While Jenny and Reza were talking he had made a peculiar little drawing, and now he was scribbling numbers.

"Oh, it wasn't the software." Wilmer grinned like an idiot. "At least, it was, but not at all in the sense that Jenny means." And then, while Celine glared, he went on, "Do you remember when we first noticed Supernova Alpha, you asked me what else it might do to the solar system? And I said, pretty much nothing, apart from melting ice for a while on the moons of the outer planets."

"I remember." With anyone but Wilmer, you would bat them over the head if they chose such an awful time to wander way off the subject. With Wilmer you waited. His digressions always came back to the point.

"Well, I was wrong," he said. "Stupidly wrong. Wrong in a way that anyone with a year or two of elementary physics could point out." He turned the sheet, so that they could see his drawing. It was of three concentric circles, with arrows pointing out from the second one toward the outermost. "We all know the pressure/volume/temperature relation for an ideal gas, Pv = RT. A planetary atmosphere satisfies that, almost perfectly. Increase the temperature and leave the pressure the same, and the volume increases linearly. Here's Earth's surface." He pointed to the inner circle. "Above it lies the atmosphere. Pump in heat, an incredible amount of it, from Supernova Alpha. For a couple of months it's like having two suns in the sky. The temperature of the surface rises. The atmosphere expands. Where does it go? The only place it can go." He pointed at the arrows between the second and third circle. "Upward. The whole atmosphere swells."

Wilmer released the sheet of paper with the diagram, and it hovered before him in the free-fall environment of the
Schiaparelli
's cabin. "That's a general comment, but it's easy to catalog specific effects. First, there will be only a small change at ground level. The atmosphere has expanded, but its total mass remains constant. The surface will experience the same atmospheric pressure, because the whole column of air above it exerts the same downward force.

"But now think about conditions higher up. The atmosphere still becomes thinner with height, but it does so more slowly than it used to. So if you go high enough, the air is
more
dense than it was at that same height before Supernova Alpha. The drag force and frictional heating on a spacecraft will increase—and they have an
exponential
dependence on air density.

"The routines that we put into
Lewis
came from the general software library applicable to our class of orbiters. They provide an explicit calculation for drag force as a function of height, in terms of spacecraft angle of attack, mass, shape, and velocity—and air density. But it's the air density at a given height
as it was before Supernova Alpha
—not as it is now—that's in the equations. An acceptable angle of attack for a ship fifty miles up, moving through the atmosphere as it was two months ago, would be an absolute disaster today. No orbiter could stand the increased drag and heating. We saw what it did to the
Lewis.
"

Wilmer had credibility and authority on all matters scientific. He also spoke as though what he said was no more than common sense, and quite undeniable. Celine reminded herself that it was the unquestioned acceptance of authority—Zoe's authority, as head of the expedition—which had led her to remain silent before. She could not afford to do it again.

"You may be right, Wilmer. But you may be wrong." And when he stared at her in surprise—this wasn't the old Celine—she went on, "Jenny may be right, there was an error in the way the software was transferred, so Zoe's action drove the controls the wrong way. Or Reza could be right, it was pilot error on Zoe's part that destroyed the
Lewis.
The trouble is, we have no way of knowing which idea is correct. Even if you are right, there's nothing we can do to prove it."

"Oh, but there is." One nice thing about Wilmer, he was too intellectually secure to become upset when he was questioned. He rubbed at the top of his head and went on, "We lost radio telemetry for the critical period, but we have a complete visual record from the
Schiaparelli
's big scope. That provides our observables. We can compute trajectories using a variety of different assumptions—that the angle of attack was adjusted the wrong way, or that it was reduced but the drag was already too high for that to help, or any other idea that anyone has. The right model is the one which minimizes residuals between computer and observed values. We can even use the difference between computed and observed data to calculate a density function for today's atmosphere, one that best matches a computed orbit to the observations. I'm sure Jenny can handle that."

"Jenny?" Celine looked uncertainly to Jenny Kopal.

"Easily." Jenny nodded. She seemed like a woman reprieved from a death sentence. "It's a nonlinear least squares fitting problem, but we have all the routines."

"So let's do it." Celine was about to add,
Soon, so we can get out of here and down to Earth.
But she was learning. "Take as much time as you need. You tell me when you're done. Then we'll discuss what comes next."

* * *

You could force patience on yourself and everyone else, but no one said you had to like it.

Celine watched Jenny working for a few minutes, with Wilmer sitting by to assist if and when needed. Then she left the control cabin and wandered away to the
Schiaparelli
's observation chamber. She had another mystery to ponder.

Zoe had been the leader of the Mars expedition. Ludwig Holter had been second in command. No backup to those two had ever been mentioned. Oversight, or deliberate act by the selection committee?

Now Zoe and Ludwig were dead. And Celine, without making any conscious decision, seemed to have taken over the direction of the surviving group. Did she want to do that? Or, inverting the question, did she have any choice?

Celine stared out at Earth, its surface again shrouded in night. The radio silence continued, broken only by weak and sporadic signals that addressed purely local problems of food, water, and power supply. The old Earth had been a celestial beacon, a roar of radio and television signals easily picked up when the
Schiaparelli
was orbiting Mars. That had gone. The firefly glow of light from the big cities was no longer visible. In its place she saw the ruddy sparks of bush fires across much of sub-Saharan Africa.

The planet to which she so much wanted to return was nothing like the world that they had left. If they survived to land on it, they would find a tougher, wilder place.

First, though, they had to live through the descent. Who would make the crucial decisions in the hours ahead? Put like that, the question of leadership became clear. She did not trust Wilmer or Jenny to direct the group. She wasn't sure she trusted Reza to do much at all, he was showing increasing signs of strangeness. And there was no one else.

Celine left the observation chamber and headed for the control room where the others were working. True, she did not wholly trust herself. But maybe Zoe Nash, for all her apparent confidence and certainty, had felt the same way.

Uneasy lies the head.

The important question wasn't whether or not you thought you were the right one to lead. It was whether others believed you were.

* * *

What am I? What is my function?

Celine, squeezed into the improvised hammock between Wilmer and Jenny and facing away from the front of the orbiter, felt a new wave of uncertainty rising within her. Reza sat behind them at the controls. Celine didn't like that, but she had no choice. He was by far the best pilot. She could see his distorted image in the shiny rear panel, singing to himself. Unless she told him to abort in the next sixty seconds, the
Clark
would leave the safe haven of ISS-2 and begin reentry.