19 – Operation WINDMILL

When Discovery suddenly lit up like the proverbial Christmas tree, navigation and interior lights blazing from end to end, the cheer aboard Leonov might almost have been heard across the vacuum between the two ships. It turned into an ironic groan when the lights promptly went out again.

Nothing else happened for half an hour; then the observation windows of Discovery's flight deck began to glow with the soft crimson of the emergency lights. A few minutes later, Curnow and Brailovsky could be seen moving around inside, their figures blurred by the film of sulphur dust.

'Hello, Max – Walter – can you hear us?' called Tanya Orlova. Both the figures waved instantly, but made no other reply. Obviously, they were too busy to engage in casual conversation; the watchers on Leonov had to wait patiently while various lights flashed on and off, one of the three Pod Bay doors slowly opened and quickly closed, and the main antenna slewed around a modest ten degrees.

'Hello, Leonov,' said Curnow at last. 'Sorry to keep you waiting, but we've been rather busy.

'Here's a quick assessment, judging from what we've seen so far. The ship's in much better shape than I feared. Hull's intact, leakage negligible – air pressure eighty-five per cent nominal. Quite breathable, but we'll have to do a major recycling job because it stinks to high heaven.

'The best news is that the power systems are okay. Main reactor stable, batteries in good shape. Almost all the circuit-breakers were open – they'd jumped or been thrown by Bowman before he left – so all vital equipment's been safeguarded. But it will be a very big job checking everything before we have full power again.'

'How long will that take – at least for the essential systems: life-support, propulsion?'

'Hard to say, skipper. How long before we crash?'

'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.