“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 coal black 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.
The problem could be made vastly more complicated. The Galileo was riding with the earth and the moon in their yearly journey around the sun at a speed of about 19 miles per second or approximately 70,000 miles per hour as seen from outer space. In addition, the earth-moon line was sweeping around the earth once each month as it followed the moon — but Joe the Robot had compensated for that when he set them on a course to where the moon would be rather than where it was.