Norton had long since overcome the vertigo he had felt on that first ascent, but now a new fear was beginning to creep into his mind. They were so vulnerable here, on this endless climb from plain to Hub. Suppose that, when it had completed its attitude change, Rama started to accelerate?
Presumably its thrust would be along the axis. If it was in the northward direction, that would be no problem; they would be held a little more firmly against the slope which they were ascending. But if it was towards the south, they might be swept off into space, to fall back eventually on the plain far below.
He tried to reassure himself with the thought that any possible acceleration would be very feeble. Dr Perera’s calculations had been most convincing; Rama could not possibly accelerate at more than a fiftieth of a gravity, or the Cylindrical Sea would climb the southern cliff and flood an entire continent. But Perera had been in a comfortable study back on Earth, not with kilometres of overhanging metal apparently about to crash down upon his head. And perhaps Rama was designed for periodic flooding-No, that was ridiculous. It was absurd to imagine that all these trillions of tons could suddenly start moving with sufficient acceleration to shake him loose. Nevertheless, for all the remainder of the ascent, Norton never let himself get far from the security of the handrail. Lifetimes later, the stairway ended; – only a few hundred metres of vertical, recessed ladder were left. It was no longer necessary to climb this section since one man at the Hub, hauling on a cable, could easily hoist another against the rapidly diminishing gravity. Even at the bot-tom of the ladder a man weighed less than five kilos; at the top, practically zero. So Norton relaxed in the sling, grasping a rung from time to time to counter the feeble Coriolis force still try-ing to push him off the ladder. He almost forgot his knotted muscles, as he had his last view of Rama. It was about as bright now as a full moon on Earth; the overall scene was perfectly clear, but he could no longer make out the finer details. The South Pole was now partially obscured by a glowing mist; only the peak of Big Horn protruded through it – a small, black dot, seen exactly head-on.
The carefully-mapped but still unknown continent be-yond the Sea was the same apparently random patchwork that it had always been. It was too foreshortened, and too full of complex detail, to reward visual examination, and Norton scanned it only briefly.
He swept his eyes round the encircling band of the Sea, and noticed for the first time a regular pattern of disturbed water, as if waves were breaking over reefs set at geometrically precise intervals. Rama’s manoeuvring was having some effect, but a very slight one. He was sure that Sergeant Barnes would have sailed forth happily under these conditions, had he asked her to cross the Sea in her lost Resolution.
New York, London, Paris, Moscow, Rome … he said farewell to all the cities of the northern continent, and hoped the Ramans would forgive him for any damage he had done. Perhaps they would understand that it was all in the cause of science.
Then, suddenly, he was at the Hub, and eager hands reached out to grab him, and to hurry him through the airlocks. His overstrained legs and arms were trembling so uncontrollably that he was almost unable to help himself, and he was content to be handled like a half-para- lysed invalid.
The sky of Rama contracted above him, as he descended into the central crater of the Hub. As the door of the inner airlock shut off the view for ever, he found himself thinking: ‘How strange that night should be falling, now that Rama is closest to the sun!’
CHAPTER FORTY-FOUR – Space Drive
A hundred kilometres was an adequate safety margin, Norton had decided. Rama was now a huge black rect-angle, exactly broadside-on, eclipsing the sun. He had used this opportunity to fly Endeavour completely into shadow, so that the load could be taken off the ship’s cooling systems and some overdue maintenance could be carried out. Rama’s protective cone of darkness might disappear at any moment, and he intended to make as much use of it as he could. Rama was still turning; it had now swung through al-most fifteen degrees, and it was impossible to believe that some major orbit change was not imminent. On the United Planets, excitement had now reached a pitch of hysteria, but only a faint echo of this came to Endeavour. Physically and emotionally, her crew was exhausted; apart from a skeleton watch, everyone had slept for twelve hours after take-off from the North Polar Base. On doctor’s orders, Norton himself had used electro-sedation; even so, he had dreamed that he was climbing an infinite stairway.
The second day back on ship, everything had almost returned to normal; the exploration of Rama already seemed part of another life. Norton started to deal with the accumulated office work and to make plans for the future; but he refused the requests for interviews that had somehow managed to insinuate themselves into the Survey and even SPACEGUARD radio circuits. There were no messages from Mercury, and the UP General Assembly had adjourned its session, though it was ready to meet again at an hour’s notice.
Norton was having his first good night’s sleep, thirty hours after leaving Rama, when he was rudely shaken back to consciousness. He cursed groggily, opened a bleary eye at Karl Mercer – and then, like any good commander, was instantly wide awake.
‘It’s stopped turning?’
‘Yes. Steady as a rock.’
‘Let’s go to the bridge.’
The whole ship was awake; even the simps knew that something was afoot, and made anxious, meeping noises until Sergeant McAndrews reassured them with swift hand-signals. Yet as Norton slipped into his chair and fastened the restraints round his waist, he wondered if this might be yet another false alarm.
Rama was now foreshortened into a stubby cylinder, and the searing rim of the sun had peeked over one edge. Norton jockeyed Endeavour gently back into the umbra of the artificial eclipse, and saw the pearly splendour of the corona reappear across a background of the brighter stars. There was one huge prominence, at least half a million kilometres high, that had climbed so far from the sun that its upper branches looked like a tree of crimson fire.
So now we have to wait, Norton told himself. The important thing is not to get bored, to be ready to react at a moment’s notice, to keep all the instruments aligned and recording, no matter how long it takes
That was strange. The star field was shifting, almost as if he had actuated the Roll thrusters. But he had touched no controls, and if there had been any real movement, he would have sensed it at once.
‘Skipper!’ said Calvert urgently from the Nay position, ‘we’re rolling – look at the stars! But I’m getting no instrument readings!’ ‘Rate gyros operating?’
‘Perfectly normal – I can see the zero jitter. But we’re rolling several degrees a second!’
‘That’s impossible!’
‘Of course it is – but look for yourself…’
When all else failed, a man had to rely on eyeball instrumentation. Norton could not doubt that the star field was indeed slowly rotating – there went Sirius, across the rim of the port. Either the universe, in a reversion of pre-Copernican cosmology, had suddenly decided to re-volve around Endeavour; or the stars were standing still, and the ship was turning.
The second explanation seemed rather more likely, yet it involved apparently insoluble paradoxes. If the ship was really turning at this rate, he would have felt it – literally by the seat of his pants, as the old saying went. And the gyros could not all have failed, simultaneously and independently.
Only one answer remained. Every atom of Endeavour must be in the grip of some force – and only a powerful gravitational field could produce this effect. At least, no other known field…
Suddenly, the stars vanished. The blazing disc of the sun had emerged from behind the shield of Rama, and its glare had driven them from the sky.
‘Can you get a radar reading? What’s the doppler?’
Norton was fully prepared to find that this too was inoperative, but he was wrong.
Rama was under way at last, accelerating at the modest rate of O.O15 gravities. Dr Perera, Norton told himself, would be pleased; he had predicted a maximum of 0.02. And Endeavour was somehow caught in its wake like a piece of flotsam, whirling round and round behind a speeding ship…
Hour after hour, that acceleration held constant; Rama was falling away from Endeavour at steadily increasing speed. As its distance grew, the anomalous behaviour of the ship slowly ceased; the normal laws of inertia started to operate again. They could only guess at the energies in whose backlash they had been briefly caught, and Norton was thankful that he had stationed Endeavour at a safe distance before Rama had switched on its drive.