Rendezvous with Rama

40. Saboteur

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.

He glanced again at his watch; this had taken less than a minute, which meant that he was on schedule. Now for the back-up cable—and then he could head for home, in full view of the furious and frustrated Hermians.

He was just beginning to work on the second cable assembly when he felt a faint vibration in the metal he was touching. Startled, he looked back along the body of the missile.

The characteristic blue-violet glow of a plasma thruster in action was hovering round one of the attitude control jets. The bomb was preparing to move. The message from Mercury was brief, and devastating. It arrived two minutes after Rodrigo had disappeared around the edge of Rama.

Norton read it with sheer disbelief, then anger. He felt a childish impulse to radio back that all his crew were inside Rama, and it would take hours to get everyone out. But that would achieve nothing—except perhaps to test the will and nerve of the Hermians.

And why, several days before perihelion, had they decided to act? He wondered if the mounting pressure of public opinion was becoming too great, and they decided to present the rest of the human race with a fait accompli. It seemed an unlikely explanation; such sensitivity would have been uncharacteristic.

There was no way in which he could recall Rodrigo, for the scooter was now in the radio shadow of Rama and would be out of contact until they were in line of sight again. That would not be until the mission was completed—or had failed.

He would have to wait it out; there was still plenty of time—a full fifty minutes. Meanwhile, he had decided on the most effective answer to Mercury.

He would ignore the message completely, and see what the Hermians did next. Rodrigo’s first sensation, when the bomb started to move, was not one of physical fear; it was something much more devastating. He believed that the universe operated according to strict laws, which not even God Himself could disobey—much less the Hermians. No message could travel faster than light; he was five minutes ahead of anything that Mercury could do.

This could only be a coincidence—fantastic, and perhaps deadly, but no more than that. By chance, a control signal must have been sent to the bomb at about the time he was leaving Endeavour; while he was travelling fifty kilometres, it had covered eighty million.

Or perhaps this was only an automatic change of attitude, to counter overheating somewhere in the vehicle. There were places where the skin temperature approached fifteen hundred degrees, and Rodrigo had been very careful to keep in the shadows as far as possible.

A second thruster started to fire, checking the spin given by the first. No, this was not a mere thermal adjustment. The bomb was re-orientating itself, to point towards…

Useless to wonder why this was happening at this precise moment in time. There was one thing in his favour; the missile was a low-acceleration device. A tenth of a gee was the most that it could manage. He could hang on.

He checked the grapples attaching the scooter to the bomb framework, and re-checked the safety line on his own suit. A cold anger was growing in his mind, adding to his determination. Did this manoeuvre mean that the Hermians were going to explode the bomb without warning, giving Endeavour no chance to escape? That seemed incredible—an act not only of brutality but of folly, calculated to turn the rest of the solar system against them. And what would have made them ignore the solemn promise of their own Ambassador?

Whatever their plan, they would not get away with it.

The second message from Mercury was identical with the first, and arrived ten minutes later. So they had extended the deadline—Norton still had one hour. And they had obviously waited until a reply from Endeavour could have reached them before calling him again.

Now there was another factor; by this time they must have seen Rodrigo, and would have had several minutes in which to take action. Their instructions could already be on the way. They could arrive at any second.

He should be preparing to leave. At any moment, the sky-filling bulk of Rama might become incandescent along the edges, blazing with a transient glory that would far outshine the sun.

When the main thrust came on, Rodrigo was securely anchored. Only twenty seconds later, it cut off again. He did a quick mental calculation; the delta vee could not have been more than fifteen kilometres an hour. The bomb would take over an hour to reach Rama; perhaps it was only moving in close to get a quicker reaction. If so, that was a wise precaution; but the Hermians had left it too late.

Rodrigo glanced at his watch, though by now he was almost aware of the time without having to check. On Mercury, they would now be seeing him heading purposefully towards the bomb, and less than two kilometres away from it. They could have no doubt of his intentions, and would be wondering if he had already carried them out.

The second set of cables went as easily as the first; like any good workman, Rodrigo had chosen his tools well. The bomb was disarmed; or, to be more accurate, it could no longer be detonated by remote command.

Yet there was one other possibility, and he could not afford to ignore it. There were no external contact fuses, but there might be internal ones, armed by the shock of impact. The Hermians still had control over their vehicle’s movements, and could crash it into Rama whenever they wished. Rodrigo’s work was not yet completely finished.

Five minutes from now, in that control room somewhere on Mercury, they would see him crawling back along the exterior of the missile, carrying the modestly-sized wire-cutters that had neutralized the mightiest weapon ever built by man. He was almost tempted to wave at the camera, but decided that it would seem undignified; after all, he was making history, and millions would watch this scene in the years to come. Unless, of course, the Hermians destroyed the recording in a fit of pique; he would hardly blame them.

He reached the mounting of the long-range antenna, and drifted hand-over-hand along it to the big dish. His faithful cutters made short work of the multiplex feed system, chewing up cables and laser wave guides alike. When he made the last snip, the antenna started to swing slowly around; the unexpected movement took him by surprise, until he realized that he had destroyed its automatic lock on Mercury. Just five minutes from now, the Hermians would lose all contact with their servant. Not only was it impotent; now it was blind and deaf.

Rodrigo climbed slowly back to the scooter, released the shackles, and swung it round until the forward bumpers were pressing against the missile, as close as possible to its centre of mass. He brought thrust up to full power, and held it there for twenty seconds.

Pushing against many times its own mass, the scooter responded very sluggishly. When Rodrigo cut the thrust back to zero, he took a careful reading of the bomb’s new velocity vector.

It would miss Rama by a wide margin and it could be located again with precision at any future time. It was, after all, a very valuable piece of equipment.

Lieutenant Rodrigo was a man of almost pathological honesty. He would not like the Hermians to accuse him of losing their property.