The familiar strains of "Feliz Aniversário," hurled across seven hundred million miles of space at the speed of light, died away among the vision screens and instrumentation of the control deck. The Quarlos family, grouped rather self-consciously around the birthday cake on Earth, lapsed into a sudden silence. Then Sr. Quarlos, the Elder, said gruffly, "Well, Antonio, I can't think of anything else to say at the moment, except that our thoughts are with you, and we're wishing you the happiest of birthdays."363Please respect copyright.ＰＥＮＡＮＡCG0QNPatpO
"Take care, querido," Sra. Quarlos interjected tearfully. "Vá com Deus."
There was a chorus of "adeus," and the vision screen went blank. How strange to think, Quarlos told himself, that all this had happened more than one hour ago; by now his family would have dispersed again and its members would be miles from home. But in a way that time lag, though it could be frustrating, was also a blessing in disguise. Like every man of his age, Quarlos took it for granted that he could talk instantly, to anyone on Earth, anytime he wished. Now that this was no longer true, the psychological impact was profound. He had moved into a new dimension of remoteness, and almost all emotional links had been stretched beyond the yield point.
"I'm sorry to interrupt the festivities," said H.A.L., "but we have a problem."
"What is it?"Dhala and Quarlos asked simultaneously.
"I am having trouble maintaining contact with Earth. The trouble is in the BF-46 unit. My Fault Prediction Unit reports that it may fail within 72 hours."
"We'll take care of it," Dhala replied. "Show us the optical alignment."
"Here it is, Mailam. It's still O.K. at the moment."
On the display screen appeared a perfect half-moon, very brilliant against a background that was nearly star-free. It was covered with clouds, and showed not one recognizable geographical feature. Indeed, at first glance it could be easily mistaken for Venus.
But not at a second one, for there beside it was the real Moon which Venus did not possess---1/4 the size of the Earth, and in exactly the same phase. It was easy to imagine that the two bodies were mother and child, as many astronomers had believed, before the evidence of the lunar rocks had proved beyond the shadow of a doubt that the Moon had never been part of Earth.
Dhala and Quarlos studied the screen silently for thirty seconds. This image was coming to them via the long-focus TV camera mounted on the rim of the big radio dish; the crosswires at its center showed the exact orientation of the antenna. Unless the narrow pencil beam was pointed exactly at Earth, they could never transmit nor receive.
Messages in both directions would miss their target and would shoot, unheard and unseen, out through the Solar System and into the void beyond. If they were ever received, it would not be for centuries---and not by men.
"Do you know where the trouble is?" asked Dhala.
"It's intermittent and I can't localize it. But it seems to be in the BF-46 unit."
"What procedure do you suggest?"
"I recommend replacing the unit with a spare, so that we can check it over."
"O.K.---let us have the hard copy."
The information flashed on the display screen; simultaneously, a sheet of paper slid out of the slot immediately beneath it. Despite all the electronic readouts, there were times when good old-fashioned printed words were the most convenient form of record.
Dhala studied the diagrams for a moment, then he whistled.
"You could have told us," he said. "This means going outside the ship."
"I apologize," H.A.L. replied. "I assumed you know that the BF-46 unit was on the antenna mounting."
"A year ago I probably did. But there are 8,000 subsystems aboard. Fortunately, it's a straightforward job. We only have to unlock a panel and install a new unit."
"That suits me fine," said Quarlos, who was the crewmember designated for routine extravehicular activity. "I could use a change of scenery. Nothing personal, of course."
"Let's see if Central Mission agrees," said Dhala. He sat still for a few seconds, marshaling his thoughts, then began dictating a message.
"Central Mission, this is X-ray Delta-One. At 2045, on-board fault prediction unit in our niner-triple-zero computer showed Beta Phi four six three five unit as a probable failure within seventy-two hours. Request check your telemetry monitoring and suggest you review unit in your ship systems simulator. Also, confirm your approval our plan to go EVA and replace Beta-Phi four six unit prior to failure. Central Mission, this is X-ray-Delta-One, 2103 transmission concluded."
Through years of practice, Dhala could switch at a moment's notice to this jargon--which someone had once christened "Techfalar"--and back again to normal speech, without gnashing his mental gears. Now there was nothing to do but wait for the confirmation, which would take at least 2 hours as the signals made the round trip past the Martian and Jovian orbits.363Please respect copyright.ＰＥＮＡＮＡxvaaWVh0TZ
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Said message came while Dhala was trying, unsuccessfully, to beat H.A.L. at one of the geometrical pattern games stored in his memory banks.
"X-ray-Delta-One, this is Central Mission, acknowledging your 2103. We are reviewing telemetric information on our mission simulator and will advise.
"Roger your plan to go EVA and replace Beta-Phi four six unit prior to possible failure. We are working on test procedures for you to apply to the faulty unit."
The serious business having been completed, the Central Mission man reverted to normal Portuguese.
"Sorry you men are having a bit of trouble, and we don't want to add to your woes. But if it's convenient to you prior to EVA, we have a request from Public Information. Could you do a brief recording for general release, outlining the situation and explaining just what the BF-46 does. Make it as reassuring as you can. We could do it, of course, but it'll be much more convincing in your words. Hope this won't interfere too badly with your social life. X-ray-Delta-One, this is Central Mission, two-one-five-five, transmission ended."
Dhala could not help but smile at the request. There were times when Earth showed a curious insensitivity and lack of tact. "Make it reassuring," indeed!
When Quarlos joined him at the end of his sleep period, they spent ten minutes composing and polishing the reply. In the early stages of the mission, there had been countless requests from all the news media for interviews, discussions---whatever they cared to say. But as the weeks drifted by uneventfully, and the time lag increased from a few minutes to over one hour, interest had gradually slackened. In fact, since the excitement of the Jupiter flyby, one month ago, had died down, they'd made only three tapes for general release.
"Central Mission, this is X-ray-Delta-One. Here is your press statement:
"Earlier today, a minor technical problem occurred. Our H.A.L.-9000 computer predicted the failure of the BF-46 unit.
"This is a small but vital component of the communication system. It keeps our main antenna aimed at Earth to within a few thousandths of a degree. This accuracy is needed, since at our present distance of more than seven hundred million miles, Earth is only a rather faint start, and our very narrow radio beam could easily miss it.
"The antenna is kept constantly tracking Earth by motors controlled from the central computer. But these motors get their instructions via the FB-46 unit. You might compare it to a nerve center in the body, which translates the brain's orders to the muscles of a limb. If the nerve fails to pass on the proper signals, the limb is rendered useless. In our case, a breakdown of the FB-46 unit could mean that the antenna will start pointing at random. This was a common trouble with the deepspace probes of the last century. They often reached other planets, but then failed to send back any information because their antenna couldn't find Earth.
"We don't know the nature of the fault at this time, but the situation is not at all serious, and there is no cause for alarm. We have two backup BF-46s, each of which has an operational life expectancy of 20 years, so the chance that a second will fail during the course of the mission is negligible. Also, if we can diagnose the present trouble, we might be able to repair the No. 1 unit.363Please respect copyright.ＰＥＮＡＮＡoFpb2vxU7I
"Antonio Quarlos, who is specially qualified for this kind of work, will go outside the ship and replace the faulty unit with the backup. At the same time, he will take the opportunity of checking the hull and repairing some micropunctures that have been to small to merit a special EVA.363Please respect copyright.ＰＥＮＡＮＡnc0vLk7Xz3
"Apart from this minor problem, the mission is still going uneventfully and should continue in the same manner.
"Central Mission, this is X-ray-Delta-One, two-one-zero-four, transmission complete."363Please respect copyright.ＰＥＮＡＮＡ0WwEt2VYkv
