But now Brazil was invisible, and even South America was hard to see. Though the low-thrust plasma drive had long since been shut down, Pesquisador was still coasting with her slender arrowlike body pointed away from Earth, and all her high-powered optical gear was oriented toward the outer planets, where her destiny lay.420Please respect copyright.ＰＥＮＡＮＡtxBby4UxHI
There was one telescope, however, that was permanently aimed at Earth. It was mounted like a gunsight on the rim of the ship's long-range antenna, and checked that the great parabolic bowl was rigidly locked upon is faraway target. While Earth remained centered in the crosswires, the vital communication link was intact, and messages could come and go along the invisible beam that lengthened more than two million miles with every day that passed.
At least once in every watch period Dhala would look homeward through the antenna-alignment telescope. As Earth was now far back toward the sun, its darkened hemisphere faced Pesquisador, and on the central display screen the planet appeared as a dazzling silver crescent, like a second Venus in our solar system.
It was rare that any geographical features could be identified in that ever-shrinking arc of light, for cloud and haze hid them, but even the darkened portion of the disk was endlessly fascinating. It was sprinkled with shining cities, sometimes they burned with a steady light, sometimes they twinkled like fireflies as atmospheric tremors passed over them.
There were also periods when, as the Moon swung to and fro in its orbit, it shone down like a great lamp upon the darkened seas and continents of Earth. Then, with a thrill of recognition, Dhala could often glimpse familiar coastlines shining in that spectral lunar light. Sometimes, when the Pacific was calm, he could even see the moonglow shimmering across its face; and he would remember nights beneath the palm trees of tropical lagoons.
Yet he had no regrets for these lost beauties. He had enjoyed them all, in his 35 years of life; and he was determined to enjoy them again, when he returned rich and famous. Meanwhile, distance made them all the more precious.
The 6th member of the crew cared for none of these things because it wasn't human. It was the highly advanced H.A.L. 9000 computer, the brain and nervous system of the ship.
H.A.L (Heuristically programmed ALgorithimc computer) was a masterpiece of the 3rd computer breakthrough. Apparently these occurred at twenty-year intervals, and the thought that another one was now imminent already bothered a great many people.
The first had been in the 1949s, when the long-obsolete vacuum tube had made possible such clumsy, high-speed morons as ENIAC and its successors. Then, in the 1960s, solid-state microelectronics had been perfected. With its advent, it was clear that artificial intelligences at least as powerful as Man's need be no bigger than office desks---if only one knew how to make them.
Probably nobody would ever know this; it did not matter. In the 2090s, Seth and Agu had shown how neural networks could be generated automatically---self replicated---in accordance with any arbitrary learning program. Artificial brains could be grown by a process strikingly analogous to the development of a human brain. In any given case; the precise details would never be known, and even if they were, they would be millions of times too complex for human understanding. Whatever way it worked, the final result was a machine intelligence that could reproduce (some would say "mimic") most of the activities of the human brain and with far greater speed and reliability. It was extremely expensive, and only a few units of the H.A.L. 9000 series had yet been built; but the old just that it would always be easier to make organic brains by unskilled labor was starting to sound a little bit old hat.
H.A.L. had been trained for this mission as thoroughly as his human colleagues--and at many times their rate of input, for in addition to his intrinsic speed, he never slept. His prime task was to monitor the life-support systems, continually checking oxygen pressure, temperature, hull leakage, radiation, and all the other interlocking factors upon which the lives of the fragile human cargo depended. He could carry out the intricate navigational corrections, and execute the needed flight maneuvers when it was time to change course. And he could watch over the hibernators, making any necessary adjustments to their environment and doling out the minute quantities of intravenous fluids that kept them alive.
The first generations of computers had received their inputs through glorified typewriter keyboards, and had replied through high-speed printers and visual displays. H.A.L could do this when needed, but most of his communication with his shipmates was by means of the spoken word. Dhala and Quadros could speak to H.A.L as if he were a human being and he would reply in the perfect idiomatic Portuguese he had learned during the fleeting weeks of his electronic childhood.
Whether H.A.L. could actually think was a question that had been settled by the British mathematician Alan Turing back in the 1940s. Turing had pointed out that, if one could carry out a long conversation with a machine--whether by typewriter or microphone was irrelevant---without being able to distinguish between its replies and those that a human might give, then the machine was thinking, by any sensible definition of the word. H.A.L. could pass the Turing test easily. 420Please respect copyright.ＰＥＮＡＮＡ2eelb6Hz3b
The time might even come when H.A.L. would take command of the ship. In an emergency, if nobody answered his hails, he would attempt to wake up the sleeping members of the crew, by electrical and chemical stimulation. If they did not respond, he would radio Earth for further instructions.420Please respect copyright.ＰＥＮＡＮＡgG36sLwIQJ
And then, if there was no reply from Earth, he would take what measures he deemed necessary to protect the ship and to continue the mission---whose real purpose he alone knew, and which his human colleagues could never have guessed.420Please respect copyright.ＰＥＮＡＮＡ3c1ipUfjaK
Quadros and Dhala had often humorously referred to themselves as caretakers or janitors aboard a ship that could really run itself. They would've been astonished, and more than a little indignant, to discover how much truth that jest contained.420Please respect copyright.ＰＥＮＡＮＡQnk6FSMPoA
