It was no use relying any further on logical arguments and the endless mapping of alternative futures. That way one could go round and round in circles for ever. The time had come to listen to his inner voices.

He returned the calm, steady gaze across the centuries. “I agree with you, Captain,” he whispered. “The human race has to live with its conscience. Whatever the Hermians argue, survival is not everything.”

He pressed the call button for the bridge circuit and said slowly, “Lieutenant Rodrigo—I’d like to see you.”

Then he closed his eyes, hooked his thumbs in the restraining straps of his chair, and prepared to enjoy a few moments of total relaxation.

It might be some time before he would experience it again.

The scooter had been stripped of all unnecessary equipment; it was now merely an open framework holding together propulsion, guidance and life-support systems. Even the seat for the second pilot had been removed, for every kilogram of extra mass had to be paid for in mission time.

That was one of the reasons, though not the most important, why Rodrigo had insisted on going alone. It was such a simple job that there was no need for any extra hands, and the mass of a passenger would cost several minutes of flight time. Now the stripped-down scooter could accelerate at over a third of a gravity; it could make the trip from Endeavour to the bomb in four minutes. That left six to spare; it should be sufficient.

Rodrigo looked back only once when he had left the ship; he saw that, as planned, it had lifted from the central axis and was thrusting gently away across the spinning disc of the North Face. By the time he reached the bomb, it would have placed the thickness of Rama between them.

He took his time, flying over the polar plain. There was no hurry here, because the bomb’s cameras could not yet see him, and he could therefore conserve fuel. Then he drifted over the curving rim of the world—and there was the missile, glittering in sunlight fiercer even than that shining on the planet of its birth.

Rodrigo had already punched in the guidance instructions. He initiated the sequence; the scooter spun on its gyros, and came up to full thrust in a matter of seconds. At first the sensation of weight seemed crushing; then Rodrigo adjusted to it. He had, after all, comfortably endured twice as much inside Rama—and had been born under three times as much on Earth.

The huge, curving exterior wall of the fifty-kilometre cylinder was slowly falling away beneath him as the scooter aimed itself directly at the bomb. Yet it was impossible to judge Rama’s size, since it was completely smooth and featureless—so featureless, indeed, that it was difficult to tell that it was spinning.

One hundred seconds into the mission; he was approaching the halfway point. The bomb was still too far away to show any details, but it was much brighter against the jet-black sky. It was strange to see no stars—not even brilliant Earth or dazzling Venus; the dark filters which protected his eyes against the deadly glare made that impossible. Rodrigo guessed that he was breaking a record; probably no other man had ever engaged in extra-vehicular work so close to the sun. It was lucky for him that solar activity was low.

At two minutes ten seconds the flip-over light started flashing, thrust dropped to zero, and the scooter spun through 180 degrees. Full thrust was back in an instant, but now he was decelerating at the same mad rate of three metres per second squared—rather better than that, in fact, since he had lost almost half his propellant mass. The bomb was twenty-five kilometres away; he would be there in another two minutes. He had hit a top speed of fifteen hundred kilometres an hour—which, for a space scooter, was utter insanity, and probably another record. But this was hardly a routine EVA, and he knew precisely what he was doing.

The bomb was growing; and now he could see the main antenna, holding steady on the invisible star of Mercury. Along that beam, the image of his approaching scooter had been flashing at the speed of light for the last three minutes. There were still two to go, before it reached Mercury.

What would the Hermians do, when they saw him? There would be consternation, of course; they would realize instantly that he had made a rendezvous with the bomb several minutes before they even knew he was on the way. Probably some stand-by observer would call higher authority—that would take more time. But even in the worst possible case—even if the officer on duty had authority to detonate the bomb, and pressed the button immediately—it would take another five minutes for the signal to arrive.

Though Rodrigo was not gambling on it—Cosmo-Christers never gambled—he was quite sure that there would be no such instantaneous reaction. The Hermians would hesitate to destroy a reconnaissance vehicle from Endeavour, even if they suspected its motives. They would certainly attempt some form of communication first—and that would mean more delay.

And there was an even better reason; they would not waste a gigaton bomb on a mere scooter. Wasted it would be, if it was detonated twenty kilometres from its target. They would have to move it first. Oh, he had plenty of time… but he would still assume the very worst.

He would act as if the triggering impulse would arrive in the shortest possible time—just five minutes.

As the scooter closed in across the last few hundred metres, Rodrigo quickly matched the details he could now see with those he had studied in the photographs taken at long range. What had been only a collection of pictures became hard metal and smooth plastic—no longer abstract, but a deadly reality.

The bomb was a cylinder about ten metres long and three in diameter—by a strange coincidence, almost the same proportions as Rama itself. It was attached to the framework of the carrier vehicle by an open latticework of short I-beams. For some reason, probably to do with the location of the centre of mass, it was supported at right angles to the axis of the carrier, so that it conveyed an appropriately sinister hammerhead impression. It was indeed a hammer, one powerful enough to smash a world.

From each end of the bomb, a bundle of braided cables ran along the cylindrical side and disappeared through the latticework into the interior of the vehicle. All communication and control was here; there was no antenna of any kind on the bomb itself. Rodrigo had only to cut those two sets of cables and there would be nothing here but harmless, inert metal.

Although this was exactly what he had expected, it still seemed a little too easy. He glanced at his watch; it would be another thirty seconds before the Hermians, even if they had been watching when he rounded the edge of Rama, could know of his existence. He had an absolutely certain five minutes for uninterrupted work—and a ninety-nine per cent probability of much longer than that.

As soon as the scooter had drifted to a complete halt, Rodrigo grappled it to the missile framework so that the two formed a rigid structure. That took only seconds; he had already chosen his tools, and was out of the pilot’s seat at once, only slightly hampered by the stiffness of his heavy-insulation suit.

The first thing he found himself inspecting was a small metal plate bearing the inscription:

Rodrigo suspected that, in a very few minutes, Mr. Jones might be rather busy.

The heavy wire-cutters made short work of the cable. As the fist strands parted, Rodrigo gave scarcely a thought to the fires of hell that were pent up only centimetres away; if his actions triggered them, he would never know.