The night had not yet finished with its surprises. Somewhere around the orbit of Mars, Tanya’s brief report passed a message going in the opposite direction.
Betty Fernandez had talked at last, Both the CIA and the National Security Agency were furious; their combined blandishments, appeals to patriotism, and veiled threats had failed completely – yet the producer of a sleazy gossip network had succeeded, thereby making himself immortal in the annals of Videodom.
It was half luck, half inspiration. The news director of ‘Hello, Earth!’ had suddenly realized that one of his staff bore a striking likeness to David Bowman; a clever makeup artist had made it perfect. Jos� Fernandez could have told the young man that he was taking a terrible risk, but he had the good fortune that often favours the brave. Once he had got his foot inside the door, Betty had capitulated. By the time she had – quite gently – thrown him out, he had obtained essentially the whole story. And to do him credit, he had presented it with a lack of leering cynicism quite uncharacteristic of his network. It got him that year’s Pulitzer.
‘I wish,’ Floyd said rather wearily to Sasha, ‘she’d talked earlier. It would have saved me a lot of trouble. Anyway, that settles the argument. Tanya can’t possibly have any doubts now. But we’ll leave it until she wakes up – don’t you agree?’
‘Of course – it’s not urgent, even though it’s certainly important. And she’ll need the sleep. I have a feeling none of us will get much from now on.’
I’m sure you’re right, thought Floyd. He felt very tired, but even if he had not been on duty he would have found it impossible to sleep. His mind was too active, analysing the events of this extraordinary night, trying to anticipate the next surprise.
In one way, he felt an enormous sense of relief: All uncertainty about their departure was surely ended; Tanya could have no further reservations.
But a much greater uncertainty remained. What was happening?
There was only one experience in Floyd’s life that matched the situation. As a very young man, he had once gone canoeing with some friends down a tributary of the Colorado River – and they had lost their way.
They had been swept faster and faster between the canyon walls, not completely helpless, but with only enough control to avoid being swamped. Ahead might be rapids – perhaps even a waterfall; they did not know. And in any case, there was little they could do about it.
Once again, Floyd felt himself in the grip of irresistible forces, sweeping him and his companions toward an unknown destiny. And this time the dangers were not only invisible; they might be beyond human comprehension.
45
Escape Manoeuvre
‘This is Heywood Floyd, making what I suspect – indeed, hope – will be my last report from Lagrange.
‘We are now preparing for the return home; in a few days we will leave this strange place, here on the line between Io and Jupiter where we made our rendezvous with the huge, mysteriously vanished artifact we christened Big Brother. There is still not a single clue as to where it has gone – or why.
‘For various reasons, it seems desirable for us not to remain here longer than necessary. And we will be able to leave at least two weeks earlier than we had originally planned by using the American ship Discovery as a booster for the Russian Leonov.
‘The basic idea is simple; the two ships will be joined together, one mounted piggyback on the other. Discovery will burn all its propellant first, accelerating both vessels in the desired direction. When its fuel is exhausted, it will be cut loose – like an empty first stage – and Leonov will start to fire its engines. It won’t use them earlier, because if it did it would waste energy dragging along the dead weight of Discovery.
‘And we’re going to use another trick, which – like so many of the concepts involved in space travel – at first sight seems to defy common sense. Although we’re trying to get away from Jupiter, our first move is to get as close to it as we possibly can.
‘We’ve been there once before, of course, when we used Jupiter’s atmosphere to slow us down and get into orbit around the planet. This time we won’t go quite so close – but very nearly.
‘Our first burn, up here in the 350,000-kilometres-high orbit of Io, will reduce our velocity, so that we fall down to Jupiter and just graze its atmosphere. Then, when we’re at the closest possible point, we’ll burn all our fuel as quickly as we can, to increase speed and inject Leonov into the orbit back to Earth.
‘What’s the point of such a crazy manoeuvre? It can’t be justified except by highly complex mathematics, but I think the basic principle can be made fairly obvious.
‘As we allow ourselves to fall into Jupiter’s enormous gravity field, we’ll gain velocity – and hence energy. When I say “we”, I mean the ships and the fuel they carry.
‘And we’re going to burn the fuel right there – at the bottom of Jupiter’s “gravity well” – we’re not going to lift it up again. As we blast it out from our reactors, it will share some of its acquired kinetic energy with us. Indirectly, we’ll have tapped Jupiter’s gravity, to speed us on the way back to Earth. As we used the atmosphere to get rid of our excess velocity when we arrived, this is one of the rare cases when Mother Nature – usually so frugal – allows us to have it both ways.
‘With this triple boost – Discovery’s fuel, its own, and Jupiter’s gravity – Leonov will head sunward along a hyperbola that will bring it to Earth five months later. At least two months earlier than we could have managed otherwise.
‘You will doubtless wonder what will happen to the good old Discovery. Obviously, we can’t bring it home under automatic control, as we had originally planned. With no fuel, it will be helpless.
‘But it will be perfectly safe. It will continue to loop round and round Jupiter on a highly elongated ellipse, like a trapped comet. And perhaps one day some future expedition may make another rendezvous, with enough extra fuel to bring it back to Earth. However, that certainly won’t happen for a good many years.
‘And now we must get ready for our departure. There is still much work to be done, and we won’t be able to relax until that final burn starts us on the homeward orbit.
‘We won’t be sorry to leave, even though we’ve not achieved all our objectives. The mystery – perhaps the threat – of Big Brother’s disappearance still haunts us, but there’s nothing we can do about that.
‘We’ve done our best – and we’re coming home. ‘This is Heywood Floyd, signing off.’
There was a round of ironic clapping from his little audience, whose size would be multiplied many million-fold when the message reached Earth.
‘I’m not talking to you,’ retorted Floyd, with slight embarrassment. ‘I didn’t want you to hear it, anyway.’
‘You did your usual competent job, Heywood,’ said Tanya consolingly. ‘And I’m sure we all agree with everything you told the people back on Earth.’
‘Not quite,’ said a small voice, so softly that everyone had to strain in order to hear it. ‘There is still one problem.’
The observation lounge suddenly became very silent. For the first time in weeks, Floyd became aware of the faint throbbing from the main air-supply duct, and the intermittent buzz that might have been made by a wasp trapped behind a wall panel. Leonov, like all spacecraft, was full of such often inexplicable sounds, which one seldom noticed except when they stopped. And then it was usually a good idea to start investigating without further ado.
‘I’m not aware of any problem, Chandra,’ said Tanya in an ominously calm voice. ‘What could it possibly be?’
‘I’ve spent the last few weeks preparing Hal to fly thousand-day orbits back to Earth. Now all those programs will have to be dumped.’
‘We’re sorry about that,’ answered Tanya, ‘but as things have turned out, surely this is a much better -‘
‘That’s not what I mean,’ said Chandra. There was a ripple of astonishment; he had never before been known to interrupt anyone, least of all Tanya.
‘We know how sensitive Hal is to mission objectives,’ he continued in the expectant hush that followed. ‘Now you are asking me to give him a program that may result in his own destruction. It’s true that the present plan will put Discovery into a stable orbit – but if that warning has any substance, what will happen to the ship eventually? We don’t know, of course – but it’s scared us away. Have you considered Hal’s reaction to this situation?’