The Collected Stories of Arthur C. Clarke (34 page)

Originally published in
Thrilling Wonder Stories
under the title ‘Thirty Seconds—Thirty Days’, ‘Breaking Strain’ was one of the stories incorporated into the film and novel,
2001
.

Grant was writing up the
Star Queen
’s log when he heard the cabin door opening behind him. He didn’t bother to look round—it was hardly necessary, for there was only one other man aboard the ship. But when nothing happened, and when McNeil neither spoke nor came into the room, the long silence finally roused Grant’s curiosity and he swung the seat round in its gimbals.

McNeil was just standing in the doorway, looking as if he had seen a ghost. The trite metaphor flashed into Grant’s mind instantly. He did not know for a moment how near the truth it was. In a sense McNeil
had
seen a ghost—the most terrifying of all ghosts—his own.

‘What’s the matter?’ said Grant angrily. ‘You sick or something?’

The engineer shook his head. Grant noticed the little beads of sweat that broke away from his forehead and went glittering across the room on their perfectly straight trajectories. His throat muscles moved, but for a while no sound came. It looked as if he were going to cry.

‘We’re done for,’ he whispered at last. ‘Oxygen reserve’s gone.’

Then he did cry. He looked like a flabby doll, slowly collapsing on itself. He couldn’t fall for there was no gravity, so he just folded up in mid-air.

Grant said nothing. Quite unconsciously he rammed his smouldering cigarette into the ash-tray, grinding it viciously until the last tiny spark had died. Already the air seemed to be thickening around him as the oldest terror of the spaceways gripped him by the throat.

He slowly loosed the elastic straps, which, while he was seated, gave some illusion of weight and with an automatic skill launched himself towards the doorway. McNeil did not offer to follow. Even making every allowance for the shock he had undergone, Grant felt he was behaving very badly. He gave the engineer an angry cuff as he passed and told him to snap out of it.

The hold was a large hemispherical room with a thick central column which carried the controls and cabling to the other half of the dumb-bell-shaped spaceship a hundred metres away. It was packed with crates and boxes arranged in a surrealistic three-dimensional array that made very few concessions to gravity.

But even if the cargo had suddenly vanished Grant would scarcely have noticed. He had eyes only for the big oxygen-tank, taller than himself, which was bolted against the wall near the inner door of the airlock.

It was just as he had last seen it, gleaming with aluminium paint, and the metal sides still held the faint touch of coldness that gave the only hint of their contents. All the piping seemed in perfect condition. There was no sign of anything wrong apart from one minor detail. The needle of the contents gauge lay mutely against the zero stop.

Grant gazed at that silent symbol as a man in ancient London returning home one evening at the time of the Plague might have stared at a rough cross newly scrawled upon his door. Then he banged half a dozen times on the glass in the futile hope that the needle had stuck—though he never really doubted its message. News that is sufficiently bad somehow carries its own guarantee of truth. Only good reports need confirmation.

When Grant got back to the control-room, McNeil was himself again. A glance at the opened medicine chest showed the reason for the engineer’s rapid recovery. He even essayed a faint attempt at humour.

‘It was a meteor,’ he said. ‘They tell us a ship this size should get hit once a century. We seem to have jumped the gun with ninety-five years still to go.’

‘But what about the alarms? The air pressure’s normal—how could we have been holed?’

‘We weren’t,’ McNeil replied. ‘You know how the oxygen circulates night-side through the refrigerating coils to keep it liquid? The meteor must have smashed them and the stuff simply boiled away.’

Grant was silent, collecting his thoughts. What had happened was serious—deadly serious—but it need not be fatal. After all, the voyage was more than three-quarters over.

‘Surely the regenerator can keep the air breathable, even if it does get pretty thick?’ he asked hopefully.

McNeil shook his head. ‘I’ve not worked it out in detail, but I know the answer. When the carbon dioxide is broken down and the free oxygen gets cycled back, there’s a loss of about ten per cent. That’s why we have to carry a reserve.’

‘The spacesuits!’ cried Grant in sudden excitement. ‘What about their tanks?’

He had spoken without thinking, and the immediate realisation of his mistake left him feeling worse than before.

‘We can’t keep oxygen in them—it would boil off in a few days. There’s enough compressed gas there for about thirty minutes—merely long enough for you to get to the main tank in an emergency.’

There must be a way out—even if we have to jettison cargo and run for it. Let’s stop guessing and work out exactly where we are.’

Grant was as much angry as frightened. He was angry with McNeil for breaking down. He was angry with the designers of the ship for not having seen this God-knew-how-many-million-to-one chance. The deadline might be a couple of weeks away and a lot could happen before then. The thought helped for a moment to keep his fears at arm’s length.

This was an emergency, beyond a doubt, but it was one of those peculiarly protracted emergencies that seem to happen only in space. There was plenty of time to think—perhaps too much time.

Grant strapped himself in the pilot’s seat and pulled out a writing-pad.

‘Let’s get the facts right,’ he said with artificial calmness. ‘We’ve got the air that’s still circulating in the ship and we lose ten per cent of the oxygen every time it goes through the regenerator. Chuck me over the Manual, will you? I never remember how many cubic metres we use a day.’

In saying that the
Star Queen
might expect to be hit by a meteor once every century, McNeil had grossly but unavoidably over-simplified the problem. For the answer depended on so many factors that three generations of statisticians had done little but lay down rules so vague that the insurance companies still shivered with apprehension when the great meteor showers went sweeping like a gale through the orbits of the inner worlds.

Everything depends, of course, on what one means by the word meteor. Each lump of cosmic slag that reaches the surface of the Earth has a million smaller brethren who perish utterly in the no-man’s-land where the atmosphere has not quite ended and space has yet to begin—that ghostly region where the weird Aurora sometimes walks by night.

These are the familiar shooting stars, seldom larger than a pin’s head, and these in turn are outnumbered a million-fold again by particles too small to leave any visible trace of their dying as they drift down from the sky. All of them, the countless specks of dust, the rare boulders and even the wandering mountains that Earth encounters perhaps once every million years—all of them are meteors.

For the purposes of space-flight, a meteor is only of interest if, on penetrating the hull of a ship, it leaves a hole large enough to be dangerous. This is a matter of relative speeds as well as size. Tables have been prepared showing approximate collision times for various parts of the Solar System—and for various sizes of meteors down to masses of a few milligrams.

That which had struck the
Star Queen
was a giant, being nearly a centimetre across and weighing all of ten grams. According to the tables the waiting time for collision with such a monster was of the order of ten to the ninth days—say three million years. The virtual certainty that such an occurrence would not happen again in the course of human history gave Grant and McNeil very little consolation.

However, things might have been worse. The
Star Queen
was 115 days on her orbit and had only thirty still to go. She was travelling, as did all freighters, on the long tangential ellipse kissing the orbits of Earth and Venus on opposite sides of the Sun. The fast liners could cut across from planet to planet at three times her speed—and ten times her fuel consumption—but she must plod along her predetermined track like a street-car, taking 145 days, more or less, for each journey.

Anything more unlike the early-twentieth-century idea of a spaceship than the
Star Queen
would be hard to imagine. She consisted of two spheres, one fifty and the other twenty metres in diameter, joined by a cylinder about a hundred metres long. The whole structure looked like a matchstick-and-plasticine model of a hydrogen atom. Crew, cargo and controls were in the larger sphere, while the smaller one held the atomic motors and was—to put it mildly—out of bounds to living matter.

The
Star Queen
had been built in space and could never have lifted herself even from the surface of the Moon. Under full power her ion drive could produce an acceleration of a twentieth of a gravity, which in an hour would give her all the velocity she needed to change from a satellite of the Earth to one of Venus.

Hauling cargo up from the planets was the job of the powerful little chemical rockets. In a month the tugs would be climbing up from Venus to meet her, but the
Star Queen
would not be stopping for there would be no one at the controls. She would continue blindly on her orbit, speeding past Venus at miles per second—and five months later she would be back at the orbit of the Earth, though Earth herself would then be far away.

It is surprising how long it takes to do a simple addition when your life depends on the answer. Grant ran down the short column of figures half a dozen times before he finally gave up hope that the total would change. Then he sat doodling nervously on the white plastic of the pilot’s desk.

‘With all possible economies,’ he said, ‘we can last about twenty days. That means we’ll be ten days out of Venus when—’ His voice trailed off into silence.

Ten days didn’t sound much—but it might just as well have been ten years. Grant thought sardonically of all the hack adventure writers who had used just this situation in their stories and radio serials. In these circumstances, according to the carbon-copy experts—few of whom had ever gone beyond the Moon—there were three things that could happen.

The proper solution—which had become almost a cliché—was to turn the ship into a glorified greenhouse or a hydroponics farm and let photosynthesis do the rest. Alternatively one could perform prodigies of chemical or atom engineering—explained in tedious technical detail—and build an oxygen-manufacturing plant which would not only save your life—and of course the heroine’s—but would also make you the owner of fabulously valuable patents. The third or
deus ex machina
solution was the arrival of a convenient spaceship which happened to be matching your course and velocity exactly.

But that was fiction and things were different in real life. Although the first idea was sound in theory there wasn’t even a packet of grass-seed aboard the
Star Queen
. As for feats of inventive engineering, two men—however brilliant and however desperate—were not likely to improve in a few days on the work of scores of great industrial research organisations over a full century.

The spaceship that ‘happened to be passing’ was, almost by definition, impossible. Even if other freighters had been coasting on the same elliptic path—and Grant knew there were none—then by the very laws that governed their movements they would always keep their original separations. It was not quite impossible that a liner, racing on its hyperbolic orbit, might pass within a few hundred thousand kilometres of them—but at a speed so great that it would be as inaccessible as Pluto.

‘If we threw out the cargo,’ said McNeil at last, ‘would we have a chance of changing our orbit?’

Grant shook his head.

‘I’d hoped so,’ he replied, ‘but it won’t work. We could reach Venus in a week if we wished—but we’d have no fuel for braking and nothing from the planet could catch us as we went past.’

‘Not even a liner?’

‘According to
Lloyd’s Register
Venus has only a couple of freighters at the moment. In any case it would be a practically impossible manoeuvre. Even if it could match our speed, how would the rescue ship get back? It would need about fifty kilometres a second for the whole job!’

‘If we can’t figure a way out,’ said McNeil, ‘maybe someone on Venus can. We’d better talk to them.’

‘I’m going to,’ Grant replied, ‘as soon as I’ve decided what to say. Go and get the transmitter aligned, will you?’

He watched McNeil as he floated out of the room. The engineer was probably going to give trouble in the days that lay ahead. Until now they had got on well enough—like most stout men McNeil was good-natured and easygoing. But now Grant realised that he lacked fibre. He had become too flabby—physically and mentally—through living too long in space.

A buzzer sounded on the transmitter switchboard. The parabolic mirror out on the hull was aimed at the gleaming arc-lamp of Venus, only ten million kilometres away and moving on an almost parallel path. The three-millimetre waves from the ship’s transmitter would make the trip in little more than half a minute. There was bitterness in the knowledge that they were only thirty seconds from safety.