‘Minimum present prediction is ten days. But you know how that’s changed up – and down.’
‘Well, if we don’t run into any major snags, we can haul Discovery up to a stable orbit away from this hellhole – oh, I’d say inside a week.’
‘Anything you need?’
‘No – Max and I are doing fine. We’re going into the carousel now, to check the bearings. I want to get it running as soon as possible.’
‘Pardon me, Walter – but is that important? Gravity’s convenient, but we’ve managed without any for quite a while.’
‘I’m not after gravity, though it will be useful to have some aboard. If we can get the carousel running again, it will mop up the ship’s spin – stop it tumbling. Then we’ll be able to couple our airlocks together, and cut out EVAs. That will make work a hundred times easier.’
‘Nice idea, Walter – but you’re not going to mate my ship to that… windmill. Suppose the bearings seize up and the carousel jams? That would tear us to pieces.’
‘Agreed. We’ll cross that bridge when we come to it. I’ll report again as soon as I can.’
No one had much rest for the next two days. By the end of that time, Curnow and Brailovsky had practically fallen asleep in their suits, but had completed their survey of Discovery and found no unpleasant surprises. Both the Space Agency and the State Department were relieved by the preliminary report; it allowed them to claim, with some justification, that Discovery was not a derelict but a ‘temporarily decommissioned United States Spacecraft’. Now the task of reconditioning had to begin.
Once power had been restored, the next problem was the air; even the most thorough housecleaning operations had failed to remove the stink. Curnow had been right in identifying its source as food spoiled when refrigeration had failed; he also claimed, with mock seriousness, that it was quite romantic. ‘I’ve only got to close my eyes,’ he asserted, ‘and I feel I’m back on an old-time whaling ship. Can you imagine what the Pequod must have smelled like?’
It was unanimously agreed that, after a visit to Discovery, very little effort of the imagination was required. The problem was finally solved – or at least reduced to manageable proportions – by dumping the ship’s atmosphere. Fortunately, there was still enough air in the reserve tanks to replace it.
One piece of very welcome news was that ninety per cent of the propellant needed for the return journey was still available; choosing ammonia instead of hydrogen as working fluid for the plasma drive had paid off handsomely. The more efficient hydrogen would have boiled off into space years ago, despite the insulation of the tanks and the frigid temperature outside. But almost all the ammonia had remained safely liquified, and there was enough to get the ship back to a safe orbit around the Earth. Or at least around the Moon.
Checking Discovery’s propellerlike spin was perhaps the most critical step in getting the ship under control. Sasha Kovalev compared Curnow and Brailovsky to Don Quixote and Sancho Panza, and expressed the hope that their windmill-tilting expedition would end more successfully.
Very cautiously, with many pauses for checking, power was fed to the carousel motors and the great drum was brought up to speed, reabsorbing the spin it had long ago imparted to the ship. Discovery executed a complex series of precessions, until eventually its end-over-end tumble had almost vanished. The last traces of unwanted rotation were neutralized by the attitude-control jets, until the two ships were floating motionless side by side, the squat, stocky Leonov dwarfed by the long, slender Discovery.
Transfer from one to the other was now safe and easy, but Captain Orlova still refused to permit a physical linkup. Everyone agreed with this decision, for Io was coming steadily closer; they might yet have to abandon the vessel they had worked so hard to save.
The fact that they now knew the reason for Discovery’s mysterious orbital decay did not help in the least. Every time the ship passed between Jupiter and Io, it sliced through the invisible flux-tube linking the two bodies – the electric river flowing from world to world. The resulting eddy currents induced in the ship were continually slowing it down, braking it once every revolution.
There was no way to predict the final moment of impact, for the current in the flux-tube varied wildly according to Jupiter’s own inscrutable laws. Sometimes there were dramatic surges of activity accompanied by spectacular electric and auroral storms around Io. Then the ships would lose altitude by many kilometres, at the same time becoming uncomfortably hot before their thermal control systems could readjust.
This unexpected effect had scared and surprised everyone before the obvious explanation was realized. Any form of braking produces heat, somewhere; the heavy currents induced in the hulls of Leonov and Discovery turned them briefly into low-powered electric furnaces. It was not surprising that some of Discovery’s food supply had been ruined during the years the ship had been alternately cooked and cooled.
The festering landscape of Io, looking more than ever like an illustration from a medical textbook, was only five hundred kilometres away when Curnow risked activating the main drive, while Leonov stood off at a very respectful distance. There were no visible effects – none of the smoke and fire of the old-time chemical rockets – but the two ships drew slowly apart as Discovery gained speed. After a few hours of very gentle manoeuvring, both ships had raised themselves a thousand kilometres; now there was time to relax briefly, and to make plans for the next stage in the mission.
‘You’ve done a wonderful job, Walter,’ said Surgeon-Commander Rudenko, putting her ample arm around the exhausted Curnow’s shoulders. ‘We’re all proud of you.’
Very casually, she broke a small capsule under his nose. It was twenty-four hours before he woke up, annoyed and hungry.
20
Guillotine
‘What is it?’ asked Curnow with mild distaste, hefting the little mechanism in his hand. ‘A guillotine for mice?’
‘Not a bad description – but I’m after bigger game.’ Floyd pointed to a flashing arrow on the display screen, which was now showing a complicated circuit diagram.
‘You see this line?’
‘Yes – the main power supply. So?’
‘This is the point where it enters Hal’s central processing unit. I’d like you to install this gadget here. Inside the cable trunking, where it can’t be found without a deliberate search.’
‘I see. A remote control, so you can pull the plug on Hal whenever you want to. Very neat – and a non-conducting blade, too, so there won’t be any embarrassing shorts when it’s triggered. Who makes toys like this? The CIA?’
‘Never mind. The control’s in my room – that little red calculator I always keep on my desk. Put in nine nines, take the square root, and press TNT. That’s all. I’m not sure of its range – we’ll have to test that – but as long as Leonov and Discovery are within a couple of kilometres of each other, there’ll be no danger of Hal running amok again.’
‘Who are you going to tell about this… thing?’
‘Well, the only person I’m really hiding it from is Chandra.’
‘I guessed as much.’
‘But the fewer who know, the less likely it is to be talked about. I’ll tell Tanya that it exists, and if there’s an emergency you can show her how to operate it.’
‘What kind of emergency?’
‘That’s not a very bright question, Walter. If I knew, I wouldn’t need the damn thing.’
‘Guess you’re right. When do you want me to install your patented Hal-zapper?’
‘As soon as you can. Preferably tonight. When Chandra’s sleeping.’
‘Are you kidding? I don’t think he ever sleeps. He’s like a mother nursing a sick baby.’
‘Well, he’s got to come back to Leonov to eat, occasionally.’
‘I’ve news for you. The last time he went across, he tied a little sack of rice to his suit. That will keep him going for weeks.’
‘Then we’ll have to use one of Katerina’s famous knockout drops. They did a pretty good job on you, didn’t they?’
Curnow was joking about Chandra – at least, Floyd assumed that he was, though one could never be quite sure: he was fond of making outrageous statements with a perfectly straight face. It had been some time before the Russians had fully realized that; soon, in self-defence, they were prone to pre-emptive laughs even when Curnow was being perfectly serious.
Curnow’s own laugh, mercifully, had much abated since Floyd had first heard it in the upward-bound shuttle; on that occasion, it had obviously been primed by alcohol. He had fully expected to cringe from it again at the end-of-orbit party, when Leonov had finally made rendezvous with Discovery. But even on that occasion, though Curnow had drunk a good deal, he had remained as much under control as Captain Orlova herself.