The sky was black now and the stars were sharp. The image of the moon had ceased to shake and the unearthly scream of the air had died away, leaving only the tireless thunder of the jet. They were above the atmosphere, high above—free.
Cargraves yelled, "Hang on to your hats, boys! Here we go! He turned full control over to Joe the Robot pilot. That mindless, mechanical-and-electronic worthy figuratively shook his non-existent head and decided he did not like the course. The image of the moon swung "down" and toward the bow, in terms of the ordinary directions in the ship, until the rocket was headed in a direction nearly forty degrees further east than was the image of the moon.
Having turned the ship to head for the point where the moon would be when the Galileo met it, rather than headed for where it now was, Joe turned his attention to the jet. Thee cadmium plates were withdrawn a little farther; the rocket really bit in and began to dig.
Ross found that there was indeed a whole family on his chest. Breathing was hard work and his eyes seemed foggy.
If Joe had had feelings he need have felt no pride in what he had just done, for his decisions had all been made for him before the ship left the ground. Morrie had selected, with Cargraves' approval, one of several three-dimensional cams and had installed it in Joe's innards. The cam "told" Joe what sort of a course to follow to the moon, what course to head first, how fast to gun the rocket and how long to keep it up. Joe could not see the moon- Joe had never heard of the moon -but his electronic senses could perceive how the ship was headed in relation to the steady, unswerving spin of the gyros and then head the ship in the direction called for by the cam in his tummy.
The cam itself had been designed by a remote cousin of Joe's, the gteat "Eniac" computer at the University of Pennsylvania. By means of the small astrogation computer in the ship either Morrie or Cargraves could work out any necessary problem and control the Galileo by hand, but Joe, with the aid of his cousin, could do the same thing better, faster, more accurately and with unsleeping care—provided the human pilot knew what to ask of him and how to ask it.
Joe had not been invented by Cargraves; thousands of scientists, engineers, and mathematicians had contributed to his existence. His grandfathers had guided the Nazi V-2 rockets in the horror-haunted last days of World War II. His fathers had been developed for the deadly, ocean-spanning guidedmissiles of the UN world police force. His brothers and sisters were found in every rocket ship, private and commercial, passenger-carrying or unmanned, that cleft the skies of earth.
Trans-Atlantic hop or trip to the moon, it was all one to Joe. He did what his cam told him to do. He did not care, he did not even know.
Cargrave called out, "How you making out down there?"
"All right, I guess," Ross answered, his voice laboring painfully.
"I feel sick," Art admitted with a groan.
"Breathe through your mouth. Take deep breaths."
"I can't."
"Well, hang on. It won't be long."
In fact it was only fifty-five seconds at full drive until Joe, still advised by his cam, decided that they had had enough of full drive. The cadmium plates slid farther back into the power pile, thwarting the neutrons; the roar of the rocket drive lessened.
The ship did not slow down; it simply ceased to accelerate so rapidly. It maintained all the speed it had gained and the frictionless vacuum of space did nothing to slow its headlong plunge. But the acceleration was reduced to one earth-surface gravity, one g, enough to overcome the powerful tug of the earth's mighty weight and thereby permit the ship to speed ahead unchecked—a little less than one g, in fact, as the grasp of the earth was already loosening and would continue to drop off to the change-over, more than 200,000 miles out in space, where the attraction of the moon and that of the earth are equal.
For the four in the ship the reduction in the force of the jet had returned them to a trifle less than normal weight, under an artificial gravity produced by the drive of the jet.
This false "gravity" had nothing to do with the pull of the earth; the attraction of the earth can be felt only when one is anchored to it and supported by it, its oceans, or it's air.
The attraction of the earth exists out in space but the human body has no senses which can perceive it. If a man were to fall from a tremendous height, say fifty thousand miles, it would not seem to him that he was falling but rather that the earth was rushing up to meet him.
After the tremendous initial drive had eased off, Cargraves called out again to Art. "Feeling any better, kid?"
"I'm all right now," Art replied.
"Fine. Want to come up here where you can see better?"
"Sure!" responded both Art and Ross, with one voice.
"Okay. Watch your step."
"We will." The two unstrapped themselves and climbed up to the control station by means of hand and toe holds welded to the sides of the ship. Once there they squatted on the supporting beams for the pilots' chairs, one on each side. They looked out.
The moon had not been visible to them from their hammock positions after the change in course. From their new positions they could see it, near the "lower" edge of the conning port. It was full, silver white and so dazzling bright that it hurt their eyes, although not sufficiently nearer to produce any apparent increase in size. The stars around it in the coalblack sky were hard bright diamonds, untwinkling.
"Look at that," breathed Ross. "Look at old Tycho shining out like a searchlight. Boy!"
"I wish we could see the earth," said Art. "This bucket ought to have more than one view port."
"What do you expect for a dollar-six-bits?" asked Ross. "Chimes? The Galileo was a freighter."
"I can show it to you in the scope," Morrie offered, and switched on the piloting radar in the belly. The screen lit up after a few seconds but the picture was disappointing. Art could read it well enough- it was his baby -but esthetically it was unsatisfying. It was no more than a circular plot reading in bearing and distance; the earth was simply a vague mass of light on that edge of the circle which represented the astern direction.
"That's not what I want," Art objected. "I want to see it. I want to see it shape up like a globe and see the continents and the oceans."
"You'll have to wait until tomorrow, then, when we cut the drive and swing ship. Then you can see the earth and the sun, too."
"Okay. How fast are we going? Never mind—I see," he went on, peering at the instrument board. "3,300 miles per hour."
"You're looking at it wrong," Ross corrected him. "It says 14,400 miles per hour."
"You're crazy."
"Like fun. Your eyes have gone bad."
"Easy, boys, easy," Cargraves counseled. "You are looking at different instruments. What kind of speed do you want?"
"I want to know how fast we're going," Art persisted.
"Now, Art, I'm surprised at you. After all you've had every one of these instruments apart. Think what you're saying."
Art stared at the instrument board again, then looked sheepish. "Sure, I forgot. Let's see now—we've gained 14,000 and some, close to 15,000 now, miles per hour in free fall—but we're not falling."
"We're always falling," Morrie put in, smug for the moment in his status as a pilot. "You fall all the time from the second you take off, but you drive to beat the fall."
"Yes, yes, I know," Art cut him off. "I was just mixed up for a moment. Thirty-three hundred is the speed I want -- 3310 flow."
‘Speed' in space is a curiously slippery term, as it is relative to whatever point you select as ‘fixed'—but the points in space are never fixed. The speed Art settled for was the speed of the Galileo along a line from the earth to their meeting place with the moon. This speed was arrived at deep inside Joe the Robot by combining by automatic vector addition three very complicated figures: first was the accumulated acceleration put on the ship by its jet drive, second the motions imposed on the ship by its closeness to the earth—its ‘free fall' speed of which Art had spoken. And lastly, there was the spin of the earth itself, considered both in amount and direction for the time of day of the take-off and the latitude of the camp site in New Mexico. The last was subtracted, rather than added, insofar as the terms of ordinary arithmetic apply to this sort of figuring.