So, despite all honors given to physics, the line of explanation may be obliged to pass again through engineering long enough to offer one last description of Apollo-Saturn as she sat on the pad. Already not twelve minutes in the air, she is of different appearance, and soon will be unrecognizable. So it is appropriate to offer a final opportunity to the reader to begin to glimpse the structure of that remarkable mechanical white whale which rose into the air at Cape Kennedy and soon disappeared.
The ship of space was after all not one rocket, but essentially two—a brain on the end of a firecracker is how Aquarius first vulgarly would seize the idea of it—but actually it was composed of two rockets, one on top of the other, separate rockets each possessed of brain and force of propulsion. It was just that the lower rocket, the first rocket, the mighty rocket which would lift it into the air, while not entirely without a brain, had in effect the little skull which sits on the neck of a dinosaur, and the second rocket, which would travel to the moon, while almost unimaginably intelligent (and pregnant as well with a mechanical child who would reach a new land), was also possessed of its own sources of fire. In comparison to the dinosaur called Saturn, the power which propelled Apollo’s brain was modest, it was in fact about one four-hundredth of the initial force which would lift the two rockets Apollo and Saturn together but this small motor was still powerful enough to propel Apollo through all of its intricately conceived plans and projects.
Therefore, let us think of it again, not as one rocket, but two joined together, Apollo on top of Saturn, each with an explosive and a brain to direct that explosive. Of course, the first, Saturn V, the dinosaur, the launch vehicle, is not quite one rocket, it is rather one rocket made of three stages called S-IC, S-II, S-IVB, rockets one behind the other to the number of three with one brain and Instrument Unit to service them all, time them all, ignite them properly, separate them, and keep them connected to Apollo, which could in emergency even control them. Yet the launch vehicle, while composed of three rockets, can be thought of as one, because the three were merely a convenience, like successive boxcars of fuel to feed a train. Taken all together with its four parts (the first stage S-IC with the five F-1 motors, the second stage S-II with its five J-2 motors, and the third stage S-IVB with its single J-2 motor plus the Instrument Unit), our launch vehicle made up a total of two hundred and eighty-one feet in length, almost three quarters of the total height; it took up more than ninety-eight percent of the total weight; of the 6,487,354 pounds of Apollo-Saturn on the pad, 6,377,354 pounds belonged to Saturn.
In its turn, the 110,000 pounds of Apollo spacecraft also had four parts. Its base, which was not even approached until one had risen close to the height of a football field from the ground, was the SLA, the Service Lunar-Module Adapter, a shell to hold the Lunar Module or Lem. Then came the Service Module, and then the Command Module, where the astronauts were installed. Above all this was the Launch Escape Tower, the needle on top of the Command Module. That was not designed to travel through space. Indeed the needle would not even reach into orbit. Shortly after the first stage separated, the escape tower was required no longer, and so it was fired off, pulling away at the same time from the Command Module a heat shield which had protected the astronauts from the high temperatures of friction caused by their rapid ascent through the atmosphere. Therefore, it was only after three minutes and seventeen seconds of flight, at a velocity now near to two miles a second, that the astronauts were at last able to obtain a view. The tower which had just departed would not be seen again—it can be stated for obituary that it was thirty-three feet long, weighed 8,910 pounds, and had three motors. The jettison motor, designed to carry the tower itself away from Apollo, had a thrust of 31,500 pounds; the escape system motor, required to pull the Command Module away from any trouble below it at a very great speed, had almost 150,000 pounds of thrust, and a relatively little motor of 2,400 pounds of force was used as a species of rudder. The bothersome details of these three motors which are not even to be seen again have been mentioned to give an idea of the variations in thrust between different and separate rocket engines on Apollo-Saturn. There were eighty-seven motors all together, some for propulsion, some for steering, some for ullage to keep pressure on the fuels, some were even retro-rockets designed to push the separated stages away from the flying ship. Thirty-seven such motors, as different in size and thrust as the million and a half pounds of F-1 in comparison to ullage rockets of seventy-two pounds, no more! were distributed over the three stages of the launch vehicle, and that count does not include the numerous explosives (also a form of rocket) which were used to rip bolts apart, separate stages, and in case of abort, blow the tanks.
Indeed, an explosive wire wrapped around the circumference of the launch vehicle was used to separate each stage. On signal this wire belt would be detonated; hundreds of aluminum straps attaching the cylinder of one stage to the cylinder of the next would be severed at guillotine speed. Retro-rockets carefully ignited by the first explosion would then fire for a fraction of a second, just enough to push the exhausted stage a few feet back. Next the motors of the newly ignited stage would take off like a relay runner from the velocity handed over by the previous stage. In this manner, the launch vehicle rose, separated stage by stage, was consumed, and left the spacecraft in earth orbit. There, in a great circle of earth one hundred miles up, revolved the second rocket, Apollo, with its Command Module, its Service Module, its Lem, and in some nice defiance of definition the partially used third stage, which would soon be employed to fire Apollo out of earth orbit and toward the moon. That combination of spacecraft and last expendable stage of the launch vehicle, making in combination an object one hundred and ten feet long, now sailed in a circle around the earth.
IV
Orbits are not difficult to comprehend. It is gravity which stirs the depths of insomnia. We can remind ourselves that the idea that what goes up must come down is still a momentous discovery to an infant (who finds every balloon a magical beast). An adult on the contrary builds the bedrock of his common sense on the certain fall of an unsupported object. What goes up must come down. Of course the Lem in Apollo 10 would never come down again—it was off in orbit around the sun, and Mariner would not be back again, nor Ranger, nor Lunar Orbiter. And Surveyor I had landed on the moon and there it had stayed. So the moon apparently had its own kind of gravity, as did Mars, and Venus, and the planets and the sun. Every heavenly body had its domain of gravity, its field of attractive influence. Indeed every physical body did. There was a force which drew bodies together, and physics had calculated it neatly as in reverse proportion to the distance between, which was another way of saying that attraction accelerated as bodies drew nearer, it increased as the inverse function of the square of the distance. Two feet apart, bodies were only attracted to one another with one quarter of the power the same bodies would feel at one foot apart. At three feet, it was one-ninth the power, at five feet one-twenty-fifth. Of course if the bodies were only six inches apart, the force of attraction was four times as great as at one foot. That was the first part of an extraordinary relation. The second was that no matter how attracted, whether by much or little, they were attracted in inverse relation to their mass, which crudely is to say in opposite proportion to their weight. Heavy bodies would attract light bodies toward them faster than light bodies would induce movement in heavy bodies. Very heavy bodies would hardly move at all as light bodies accelerated toward them. It was more than theory: the laws of gravity were the soundest laws of behavior in the kingdom of physics—it required only that one not personify the bodies, not give them private will or curiosity or whim, no independent desire or independent resistance. Obviously, a theory of sexual mechanics could never be based on gravity. Still, gravity was a damnable mystery—why did inanimate or dead objects attract each other? And why did animate objects like human beings act like inanimate objects under certain conditions, such as jumping off a high building? Then the human body entered the laws of
physics at a weight of two hundred pounds. Since the earth had a literal weight of six billion trillion tons, there was no visible reciprocity. Dispensing with all sizable calculations of air resistance, the body fell at an increasing rate of thirty-two feet per second every second, which was the acceleration gravity gave to falling objects. From a fall of a hundred feet the two-hundred pound man would be moving about sixty-five feet a second when he hit the ground—the earth, with all of its six billion trillion tons, would not be quivering at any perceptible rate of acceleration up toward the body. Still by the width of a hair taken from an electron it had been moving toward the body which approached. Because we cannot see the movement, we tend to think it does not exist, that bodies merely fall, but in fact the reason a two-hundred pound man exhibits much the same behavior as any inanimate object in a ten-story fall is that the power with which the earth pulls on him is enormous, and the muscles which express his will are not equipped to be effective in air. So it is not so much that he falls as that he is drawn by an intense and accelerating introduction to the earth. And indeed anyone who has ever had a high fall has felt such a fierce force pulling on him. “The earth came up and socked me,” is the good tough statement a child gives to witnesses. What a ringing in the ear, what a memory of the lightning bolt!
Metaphors then arise of a charged and libidinous universe with heavenly bodies which attract each other across the silences of space. If they do not all gather together in assembly at a point, it is because they do not act simply upon each other, but are each in relation with many bodies in many directions, and all are moving as well. If they are moving fast enough and with enough force, they can resist powers of attraction calling to them from vastly larger bodies. An airplane need not descend so long as it has fuel to give its motor strength.
We are preparing, however, to brood upon the astronauts in orbit, and that is another case. They are now not flying with engines, they are coasting with motors off. They are a hundred miles up in the air, and their motors are off, and yet they do not fall. They merely continue to circle the earth once every hour and twenty-eight minutes.
Of course they are traveling fast, at eighteen thousand miles an hour we can remember, and while that is nowhere near the speed of light, 186,000 miles a second (a speed which is probably the walls of the vessel which contains the time of our universe), it is still interesting to note that eighteen thousand miles an hour is as many times greater than the rate at which a baby crawls (or Apollo-Saturn began its trip from the VAB to the pad) as the speed of light is greater than the present velocity of the spacecraft. If men could move out of infancy at half a mile an hour and get up to eighteen thousand miles an hour in one lifetime, well, who was to assume that the walls of the universe were safe from future men?
At any rate, the spacecraft was traveling at eighteen thousand miles an hour, and that speed was just great enough to keep it in orbit a hundred miles above the earth. It was of course falling, it was in fact in free fall and in a virtual vacuum (for the presence of air at one hundred miles of altitude is next to nonexistent), but it was also traveling so fast in a forward direction that it fell forward like a ball thrown into an endless chasm, and as it fell forward it fell around the curve of the earth. The earth pulled on it of course, it pulled on the spaceship with all the force of its gravity, but only succeeded in bending its path around the circumference of the earth.
It is easier if we conceive of gravity as a general condition of which magnetism is a special case. Magnetism only works a force of attraction on iron objects, whereas gravity works on all objects. Think of a cylindrical ring highly magnetized, and a steel bullet fired from a revolver which passes the ring in just such a way that the intense force of the magnetism bends the path of the bullet around the cylinder. The bullet would whip around until air resistance had slowed its speed to the point where it would circle in and touch the ring. Orbit was comparable. Even better, at one hundred miles up, air resistance was next to nonexistent, so the spaceship could stay in orbit for a long time. What peace and communality to drift over the earth from such a height, to see nations appear below on the extended field of a continent, nations no larger to the eye from a hundred miles up than the spread of a city from a passenger plane, and oceans the size of a cove. Clouds covered the earth like the wet white feathers of a bird just born, clouds with lines of logic and reentrant curves of thought, clouds gathered in nodes of spiral to signify a shift of atmospheric being—a storm was blowing across a thousand miles of sea. A planet manifest beneath, filling the window out which the astronauts would look, a planet blue and brown with white trailings of celestial ripple and wake, hints of green and dark gray and silver in the curvings and stuffings and pumpings of thousand-mile odysseys of clouds, caravans of weather, pulsations of weather. What a peace, what a calm, what a silence!
Not a chance! The sound of static filled the module, the crackling of questions and answers from earth to spacecraft, from air to ground. Into the ear of each astronaut came burning searching spitting sounds, the unclassifiable sounds of static, so much like the rush of crackling air, the consumption of something vital in space. If smell, Aquarius long had thought, was related to time, then sound was some current in space. But what was static, what special case of space? Static was a form of speech man did not comprehend. Like the dialogue of the dolphin, the communication was faster than the ear. But what fury of irritabilities was loose in the ether at this harshness perpetrated upon it!
Below the astronauts was the earth. Above them, behind them, around them, was a sky no longer blue but dark, dark as the endless night of space. They would not always see that black sky. Sometimes the shine from the earth, the moon, or the light of the sun would reflect from their module, and the sky—almost impossible to see stars in such curious reflected light—would seem a dark rose, a hellish color with glare and plays of transparency and curtains of dark. They were weightless. As their ship fell in its ever continuing circle about the earth, so they fell too. If not strapped down, or with hands on a grip, or with Velcro-soled shoes hooked to a Velcro mat, they floated through the fall of free fall as a man will fall and turn in the air before he opens his parachute. They could do small dives inside the locked spaces of the module, twists and tucks and ever revolving turns, disport like seals and monkeys and otters. That very weightlessness, that absence of gravity which space doctors worried might produce profound deteriorations of the organs and the flesh in a trip of some months’ duration, was for now a delight, a languor. Think of reaching to dispose of a full can of beer. To one’s surprise it is empty. How languorous is the arm as it comes up. John Glenn experiencing weightlessness in his first orbit had said, “Contrary to this being a problem, I think I have finally found the element in which I belong.” Of course, years later, Glenn had slipped in a tub and almost been killed. Who knew what price was in the pounds lost to weightlessness—for in every intoxication was some kind of price. Otherwise, nothing divine to economy.
Now, however, they did not have time to play. There was static in their ear, and systems and subsystems to monitor, align, check out, adjust, a Puritan ethic in the whisper of the empty spaces—keep busy in the empyrean was the whisper of those empty spaces. So they kept busy for those two and a half hours before they took off for the moon. Names and duties came their way. Alignments, static, stations.
Ground stations ready to receive their communications and relay them to Houston came into range as they moved around the earth, acquired signal, then lost signal when they moved further on. The tracking ship Vanguard in the Caribbean lost contact, the Canary Island Station acquired it, Tananarive in the Indian Ocean was next, then Carnarvon in Australia, Honeysuckle in Australia, Goldstone in California. Somewhat later, starting from an altitude of ten thousand miles, on all the way to the moon, there would be but three stations for radio communication, each one hundred and twenty degrees apart on the circumference of the earth, stations with enormous eighty-five foot dish-shaped antennae located in
Madrid; in Goldstone; and Canberra, Australia; but for now the stations were more modest, the antennae were no larger than thirty feet, the communication was close, and the data received was fed by relay into computers at Mission Control at Houston, there to go up on the wall to show in display the position of the ship.
They passed the other tracking stations in their orbit, passed them at Hawaii, at Guaymas in Mexico, Corpus Christi, in the Bermudas, the Bahamas, the tracking ship Redstone, in all there were seventeen ground stations, plus six units from ARIA (Apollo Range Instrumented Aircraft, what an acronym was ARIA!), six jets which could be used for voice relay in emergency or on unusual azimuths if Apollo passed over in unconventional orbit. But nothing was out of the ordinary today. The orbit and a half before Trans-Lunar Injection was a time of testing out communications and making their checks. The rocket thrusters which would give their spaceship its attitude, put its nose up or down, left or right, or leave it to roll, were fired in brief maneuvers, and studied by instruments in Mission Control in Houston to pass on the results. The temperature of one rocket thruster was soon discovered to be lower than the others. Queries came up from the ground.
CAPCOM: Would you confirm that your RCS heater switch for quad BRAVO is in primary? Over.
ALDRIN: You’re correct. It was not in primary. It was off. It’s on now. Thank you.
CAPCOM: Roger. Thank you.
The time-line lengthened. They were in second orbit. At a point somewhere near the Gilbert Islands, about halfway between Australia and Hawaii, they would ignite the engine on the third and remaining stage of the launch vehicle, and proceed into Trans-Lunar Injection, which is to say they would quit their earth orbit and fire up to the moon.
Of a Fire on the Moon Page 24
