The voice stopped so suddenly that Bowman froze for a moment, his hand still grasping one of the memory blocks still in circuit. Then, unexpectedly, Hal spoke again.

The speech tempo was much slower, and the words had a dead, mechanical intonation; he would never have recognized their origin.

"Good... morning... Doctor... Chandra... This is... Hal... I... am... ready... for... my first... lesson... today..."

Bowman could bear no more. He jerked out the last unit, and Hal was silent forever.

Like a tiny, complex toy, the ship floated inert, and motionless in the void. There was no way of telling that it was the swiftest object in the Solar System and that it was traveling far faster than any of the planets as they circled the Sun.

Nor was there any indication that it carried life; to the contrary, in fact. Any observer would have noticed two ominous signs: the airlock doors were gaping open – and the ship was surrounded by a thin, slowly dispersing cloud of debris.

Scattered over a volume of space already miles across were scraps of paper, metal foil, unidentifiable bits of junk – and, here and there, clouds of crystals glittering like jewels in the distant sun, where liquid had been sucked out of the ship and instantly frozen. All this was the unmistakable aftermath of disaster, like wreckage tossing on the surface of an ocean where some great ship had sunk. But in the ocean of space no ship could ever sink; even if it were destroyed, its remnants would continue to trace the original orbit forever.

Yet the ship was not wholly dead, for there was power on board. A faint blue glow was shining from the observation windows and glimmering inside the open airlock. Where there was light, there could still be life.

And now, at last, there was movement. Shadows were flickering across the blue glow inside the airlock. Something was emerging into space.

It was a cylindrical object, covered with fabric that had been roughly wound about it. A moment later it was followed by another – and yet a third. All had been ejected with considerable velocity; within minutes, they were hundreds of yards away.

Half an hour passed; then something much larger floated through the airlock. One of the pods was inching its way out into space.

Very cautiously, it jetted around the hull, and anchored itself near the base of the antenna support. A spacesuited figure emerged, worked for a few minutes on the mounting, then returned to the pod. After a while the pod retraced its path back to the airlock; it hovered outside the opening for some time, as if finding it difficult to reenter without the cooperation it had known in the past. But presently, with one or two slight bumps, it squeezed its way in.

Nothing else happened for over an hour; the three ominous packages had long since disappeared from view, as they floated in single file away from the ship.

Then the airlock doors closed, opened, and closed again. A little later, the faint blue glow of the emergency lights went out – to be replaced at once by a far more brilliant glare. Discovery was coming back to life.

Presently there was an even better sign. The great bowl of the antenna, which for hours had been staring uselessly at Saturn, began to move again. It twisted round toward the rear of the ship; looking back over the propellant tanks and the thousands of square feet of the radiating fins. It lifted its face like a sunflower seeking the sun.

Inside Discovery, David Bowman carefully centered the cross-wires that aligned the antenna on the gibbous Earth. Without automatic control, he would have to keep readjusting the beam -but it should hold steady for many minutes at a time. There were no dissenting impulses now, throwing it off target.

He began to speak to Earth. It would be over an hour before his words got there, and Mission Control learned what had happened. It would be two hours before any reply could reach him.

And it was difficult to imagine what answer Earth could possibly send, except a tactfully sympathetic, "Good-bye."

Heywood Floyd looked as if he had had very little sleep, and his face was lined with worry. But whatever his feelings, his voice sounded firm and reassuring; he was doing his utmost to project confidence to the lonely man on the other side of the Solar System.

"First of all, Dr. Bowman," be began, "we must congratulate you on the way you handled this extremely difficult situation. You did exactly the right thing in dealing with an unprecedented and unforeseen emergency.

"We believe we know the cause of your Hal Nine Thousand's breakdown, but we'll discuss that later, as it is no longer a critical problem. All we are concerned with at the moment is giving you every possible assistance, so that you can complete your mission.

"And now I must tell you its real purpose, which we have managed, with great difficulty, to keep secret from the general public. You would have been given all the facts as you approached Saturn; this is a quick summary to put you into the picture. Full briefing tapes will be dispatched in the next few hours. Everything I am about to tell you has the highest security classification.

"Two years ago, we discovered the first evidence for intelligent life outside the Earth. A slab or monolith of hard, black material, ten feet high, was found buried in the crater Tycho. Here it is."

At his first glimpse of TMA-1, with the spacesuited figures clustering around it, Bowman leaned toward the screen in openmouthed astonishment. In the excitement of this revelation – something which, like every man interested in space, he had half expected all his life – he almost forgot his own desperate predicament.

The sense of wonder was swiftly followed by another emotion. This was tremendous – but what had it to do with him? There could be only one answer. He brought his racing thoughts under control, as Heywood Floyd reappeared on the screen.

"The most astonishing thing about this object is its antiquity. Geological evidence proves beyond doubt that it is three million years old. It was placed on the Moon, therefore, when our ancestors were primitive ape-men.

"After all these ages, one would naturally assume that it was inert. But soon after lunar sunrise, it emitted an extremely powerful blast of radio energy. We believe that this energy was merely the by-product – the backwash, as it were – of some unknown form of radiation, for at the same time, several of our space probes detected an unusual disturbance crossing the Solar System. We were able to track it with great accuracy. It was aimed precisely at Saturn.

"Piecing things together after the event, we decided that the monolith was some kind of Sun-powered, or at least Sun-triggered, signaling device. The fact that it emitted its pulse immediately after sunrise, when it was exposed to daylight for the first time in three million years, could hardly be a coincidence.

"Yet the thing had been deliberately buried – there's no doubt about that. An excavation thirty feet deep had been made, the block had been placed at the bottom of it, and the hole carefully filled.

"You may wonder how we discovered it in the first place. Well, the object was easy – suspiciously easy – to find. It had a powerful magnetic field, so that it stood out like a sore thumb as soon as we started to conduct low-level orbital surveys.

"But why bury a Sun-powered device thirty feet underground? We've examined dozens of theories, though we realize that it may be completely impossible to understand the motives of creatures three million years in advance of us.

"The favorite theory is the simplest, and the most logical. It is also the most disturbing.

"You hide a Sun-powered device in darkness – only if you want to know when it is brought out into the light. In other words, the monolith may be some kind of alarm. And we have triggered it.