31
SCENARIO
TO THE FIRST APPROXIMATION IT WAS AN ELEMENTARY problem in dynamics. The mass of Kali was known to within one percent, and the velocity it would have when meeting Earth was known to twelve decimal places. Any schoolboy could work out the resulting half em vee squared of energy—and convert it into megatons of explosive.
The result was an unimaginable two million million tons—a figure that was still meaningless when expressed as a billion times the bomb that destroyed Hiroshima. And the great unknown in the equation, upon which millions of lives might depend, was the point of impact. The closer Kali approached, the smaller the margin of error, but until a few days before encounter, ground zero could not be pinned down to within better than a thousand kilometers—an estimate that many thought was worse than useless.
In any event, it would probably be sea zero, as three-quarters of the Earth’s surface was water. The most optimistic scenarios assumed an impact in mid-Pacific; there would be time to evacuate the smaller islands before they were scrubbed off the map by kilometer-high waves.
Of course, if Kali came down on land, there would be no hope for anyone within hundreds of kilometers; they would be instantly vaporized. And a few minutes later, every building over a continent-wide area would be flattened by the blast wave; even underground shelters would probably collapse, though some lucky survivors might dig themselves out.
But would they be lucky? Over and over again the media repeated the question raised by Twentieth-Century writers on thermonuclear war. “Would the living envy the dead?”
That might well prove to be the case. The aftereffects of the impact could be even worse than the immediate consequences, as the skies were blackened by smoke for months—perhaps years. Most of the world’s vegetation, and perhaps its remaining wildlife, would fail to survive the lack of sunshine and rain laced with the nitric acid produced when the fireball fused megatons of oxygen and nitrogen in the lower atmosphere.
Even with high technology, the Earth might be essentially uninhabitable for decades—and who would want to live on a devastated planet? The only safety lay in space.
But, for all but a few, that road was closed. There were not enough ships to take more than a small fraction of the human race even to the Moon—and there would be little purpose in doing so. The lunar settlements would be hard put to accommodate more than a few hundred thousand unexpected guests.
As it had for almost all the quarter-trillion human beings who had ever lived, Earth would provide both cradle and grave.
PART VI
32
THE WISDOM OF DAVID
CAPTAIN SINGH SAT ALONE IN THE LARGE, WELL-APPOINTED cabin that had been his home for longer than any other place in the Solar System. He was still dazed, but the warning from ASTROPOL, too late though it was, had done something to improve morale aboard the ship. Not much—but every little bit helped.
At least it was not their fault: they had done their duty. And who could have imagined that religious fanatics would wish to destroy the Earth?
Now that he was forced to think about the previously unthinkable, it was not so astonishing after all. Almost every decade, right through human history, self-proclaimed prophets had predicted that the world would come to an end on some given date. What was astonishing—and made one despair for the sanity of the species—was that they usually collected thousands of adherents, who sold all their no-longer-needed possessions, and waited at some appointed place to be taken up to heaven.
Though many of the “Millennialists” had been impostors, most had sincerely believed their own predictions. And if they had possessed the power, could it be doubted that, if God had failed to cooperate, they would have arranged a self-fulfilling prophecy?
Well, the Reborn, with their excellent technological resources, did have the power. All that was needed was a few kilos of explosive, some fairly intelligent software—and accomplices on Deimos. Even one would have been sufficient.
What a pity, Singh thought wistfully, that the informer had left it until too late. Perhaps it was even deliberate—an attempt to have it both ways. “I’ve satisfied my conscience—but I’ve not betrayed my religion.”
What did it matter now! Captain Singh turned his mind from useless regrets. Nothing could change the past, and now he must make his peace with the Universe.
He had lost the battle to save the planet of his birth. The fact that he was perfectly safe somehow made him feel worse; Goliath was in no danger whatsoever, and still had ample propellant to rejoin the shaken survivors of humanity on the Moon or Mars.
Well, his heart was on Mars, but some of the crew had loved ones on the Moon; he would have to put it to a vote.
Ship’s orders had never covered a situation like this.
“I still don’t understand,” said chief engineer Morgan, “why that explosive cord wasn’t detected on the pre-flight checkout.”
“Because it was easy to hide—and no one would dream of looking for such a thing,” said his Number Two. “What surprises me is that there are Reborn fanatics on Mars.”
“But why did they do it? I can’t believe that even Chrislamic crazies would want to destroy the Earth.”
“You can’t argue with their logic—if you accept their premises. God—Allah—is testing us, and we mustn’t interfere. If Kali misses—fine. If it doesn’t—well, that’s part of Her bigger plan. Maybe we’ve messed up Earth so badly it’s time to start over. Remember that old saying of Tsiolkovski’s: ‘Earth is the cradle of Mankind—but you cannot live in the cradle forever.’ Kali could be a gentle hint that it’s time to leave.”
“Some hint!”
The captain held up his hand for silence.
“The only important question now is—Moon or Mars? They’ll both need us. I don’t want to influence you”—(that was hardly true; everyone knew where he wanted to go)—“so I’d like your views first.”
The first ballot was Mars nine, Moon nine, Don’t Know one, Captain abstaining.
Each side was trying to convert the single Don’t Know—ship’s steward Sonny Gilbert, who had lived on Goliath for so long that he knew no other home—when David spoke.
“There is an alternative.”
“What do you mean?” Captain Singh demanded rather brusquely.
“It seems obvious. Even though ATLAS is destroyed, we still have a chance of saving the Earth—if we use Goliath as a mass driver. According to my calculations, we still have enough propellant to deflect Kali—in our own tanks, and the ones we’ve parked there. But we must start thrusting immediately. The longer we wait, the less the probability of success. It is now 95 percent.”
There was a moment of stunned silence on the bridge as everyone asked the question, “Why didn’t I think of this?” and immediately arrived at the answer.
David had kept his head—if one could use so inappropriate a phrase—while all the humans around him were in a state of shock. There were some compensations in being a Legal Person (nonhuman). Though David could not know Love, neither could he know Fear. He would continue to think logically, even to the edge of doom.
33
SALVAGE
“WE’RE IN LUCK,” TORIN FLETCHER REPORTED.
“We certainly need it—go on.”
“The charge was set to damage the fusion generator and thrusters beyond repair—and it did just that. I could fix them if we were back on Deimos—but not here. Then the shock ruptured the first and second tanks, so we lost thirty K of propellant. But the cut-off valves in the pipeline did just what they were supposed to do—so the rest of the hydrogen is intact.”
For the first time in hours, Robert Singh dared to hope. But there were still many problems to be solved, and an enormous amount of work to be done. Goliath had to be jockeyed into position against Kali, and some kind of scaffolding built around it to transmit the thrust to the asteroid. Fletcher had already programmed his construction robots to tackle this task, using suitable spars and gir
ders from the shattered ATLAS.
“Craziest job I’ve ever done,” he said. “I wonder what the old-timers at Kennedy would have thought if they saw a gantry holding a spaceship upside down.”
“How can you tell with Goliath?” was Sir Colin Draker’s rather unkind retort. “I’ve never been sure which end is which. You could see whether a Twentieth-Century rocket was coming or going just by looking at it. Not anymore.”
However bizarre the result may have looked to anyone except an astronautical engineer, Torin Fletcher was justly proud of his achievement. Even in a gravitational field as weak as Kali’s, the task had been barely possible. It was true that a ten-thousand-ton propellant tank “weighed” less than one ton here, and could be—slowly!—lifted into place with a ridiculously small block and tackle. But once such large masses were set moving, they were potentially deadly to creatures whose muscles and instincts had evolved in a totally different environment. It was hard to believe that a slowly drifting object could be completely unstoppable—and capable of converting into a pancake anyone who could not avoid it in time.
Thanks to a combination of skill and good luck, there were no serious accidents. Every move was carefully rehearsed in a virtual reality simulation to avoid unexpected surprises—until at last Fletcher announced: “We’re ready to go.”
Inevitably, there was a feeling of déjà vu as the second countdown proceeded. And this time there was also a sense of danger. If anything went wrong, they would not be at a safe distance from the accident. They would be part of it, though they would probably never know.
It had been weeks since Goliath had been really alive, and those aboard had felt the characteristic vibration of the plasma drive under full thrust. Slight and far-off though it seemed, there was no way of ignoring it—especially when, at regular intervals, it hit some resonant frequency of Goliath’s structure, and the whole ship gave a brief shudder.
The accelerometer reading slowly climbed from zero to just over one microgravity as thrust built up to maximum safe value. Kali’s billion tons were being gently perturbed; every day its velocity would be changed by almost one meter per second, and it would be deflected from its original path by forty kilometers. Trivial amounts as cosmic velocities and distances went, but enough to make the difference between life and death for millions on the far-off planet Earth.
Unfortunately, Goliath could operate its drive for only thirty minutes of Kali’s brief under-four-hour day; longer than that, and the asteroid’s spin would start to neutralize what had been achieved. It was a maddening limitation, but there was nothing that could be done about it.
Captain Singh waited for the first period of thrusting to end before he sent the message that the world was waiting for.
“Goliath reporting. We have successfully started the perturbation maneuver. All systems are functioning normally. Good night.”
And then he turned the ship over to David, and had his first good sleep since ATLAS had been lost. Presently he dreamed that another day had started on Kali, and that Goliath’s drive was operating exactly as planned.
He woke up, discovered it was not a dream, and promptly went back to sleep again.
34
CONTINGENCY PLAN
THOUGH THE VENERABLE SPACE-PLANE STILL CALLED Air Force One was older than most of the men and women sitting around the conference table in its historic lounge, it had been maintained with loving care and was still perfectly operational. However, it was seldom used; and this was the first time that all the members of the World Council had ever been on it at the same time. The technocrats who were the—human—brains of the planet normally conducted their business over teleconferencing circuits: but this was not normal business, and they had never faced such an awesome responsibility before.
“You’ve all had the summary of my technical staff’s report,” said the Director-General, Energy. “It was not easy to find the engineering drawings—most of them had been deliberately destroyed. However, the general principles are well known, and the Imperial War Museum in London (I’d never heard of it) has a complete twenty-megaton model—defused, of course. No problem to scale it up—if we can produce the materials in time. Inventory?”
“The tritium’s easy. But plute and weapons grade U235—no one’s needed any since we stopped using nuclear explosives for mining.”
“What about that idea of digging up some of those buried dumps and reactors?”
“We’ve looked into it, but it would be too much trouble to sort out those witches’ brews.”
“But you can do it?”
“I simply don’t know, in the time available. We’ll do our best.”
“Well, we’ll have to assume it’s good enough. That leaves the delivery system. Transport?”
“Quite straightforward. The smallest cargo freighter will do the job—on automatic, of course. Though the alternative might have appealed to some of my kamikaze ancestors.”
“Then we really have only one decision to make. Is it worth trying, or would it only make matters worse? If we can hit Kali within a thousand megatons, we may split it into two fragments. If our timing’s right, the asteroid’s spin will cause them to separate, so that both miss Earth, passing on either side of us. Or only half may impact, which could still save millions of lives….
“On the other hand—we may turn Kali into a mass of shrapnel, still moving on the same orbit. Much of it will burn up in the atmosphere—but a lot won’t. Which is better—a single mega-catastrophe in one place or hundreds of smaller ones, as fragments come in all across the hemisphere? Whichever hemisphere it is…”
Eight men sat in silence, pondering the fate of the Earth. Then one asked: “How much time—before we must decide?”
“We will know within another fifty days if Goliath has managed to deflect Kali. But we can’t sit on our hands until then—it would be much too late to do anything, if Operation Deliverance fails. I propose that we launch the missile as quickly as possible. We can always abort the mission if it proves unnecessary. Can we have a vote?”
Slowly, all hands but one were raised.
“Yes, Legal? Do you have reservations?”
“I’d like to clarify a few points. First of all, there would have to be a World Referendum: the subject comes under the Rights of Man Amendment. Luckily, there’s plenty of time for this.
“My second point may seem unimportant compared with the survival of most of the human race. But if we have to blow up Kali, will Goliath be able to get far enough away in time?”
“Certainly: they’ll have plenty of warning. Of course, we can’t guarantee absolute safety—even a million kilometers away, there might be an unlucky hit. But the danger will be negligible if the ship leaves in the direction from which the missile’s coming. All the debris will go the other way.”
“That’s reassuring: you have my vote. I still hope the entire scheme’s unnecessary—but we’d be derelict in our duty if we failed to take out an insurance policy on Planet Earth.”
35
DELIVERANCE
HUMAN BEINGS CANNOT REMAIN FOR LONG IN A STATE OF perpetual crisis; the home planet had swiftly returned to something like normal. No one really doubted—or dared to doubt—that what the media had quickly named Operation Deliverance could possibly fail.
It was true that all long-term planning had been put on hold, and most public and private business was conducted on a day-to-day basis. But the sense of impending doom had lifted, and the suicide rate had actually dropped below its normal value now that it seemed there would, after all, be a tomorrow.
Aboard Goliath, life had settled down to a steady routine. Once every revolution of Kali, maximum thrust would be switched on for thirty minutes, each time pushing the asteroid a little farther away from its original path. On Earth, the result of each firing would be reported immediately in every news bulletin. The traditional weather maps had taken second place to charts showing Kali’s present orbit, still impacting on Earth—and the desired
one, missing it completely.
The date when the world might expect to relax had been announced long in advance, and as it approached, all normal business ceased. Only the most essential services were maintained—until the moment when SPACEGUARD gave the eagerly awaited news that Kali would graze the outermost fringes of the atmosphere, producing no more than a spectacular fireworks display.
The thanksgiving celebrations were spontaneous and worldwide; there was probably not a single human being on the planet who was not involved in some manner. Goliath, of course, was bombarded with messages of congratulation.
They were received gratefully; but Captain Robert Singh and his crew were not yet prepared to relax.
Merely grazing the atmosphere was not good enough. Goliath would keep driving Kali until it would miss by at least a thousand kilometers.
Only then would victory be absolutely certain.
36
ANOMALY
KALI WAS WELL INSIDE THE ORBIT OF MARS, STILL GAINING speed as it plunged sunward, when David reported the first anomaly. It occurred during one of the powered-down periods, only a few minutes before Goliath was due to start thrusting again.
“Duty Officer,” said the computer. “I’ve detected a slight acceleration. One point two tenths of a microgee.”
“That’s impossible!”
“Now one point five,” David continued imperturbably. “Fluctuating. Down to one. Now it’s stopped. I think you should notify the captain.”
“You’re quite sure? Let me see the record.”
“Here it is.”
A jagged line, rising to a sharp peak and then falling back to zero, appeared on the main monitor. Something—not Goliath—was giving Kali a minute but perceptible nudge; the impulse had lasted just over ten seconds.
Captain Singh’s first question, when he had answered the call from the bridge, was “Can you pinpoint it?”
The Hammer of God Page 12
