A TRINITY -Jack R

A TRINITY -Jack R. Holt

AN UNSUCCESSFUL FLIGHT God protects children and fools. -American Proverb

When I was a boy in Oklahoma, I was very interested in chemistry and some of its ramifications (especially those that make noise). I worked hard to perfect black gunpowder so that it would sound as good as the firecrackers that were so easily obtained in Oklahoma in those days. Bottle rockets, too, were some of my favorite pastimes. It was just a small step from there to an interest in model rockets. Not only because I enjoyed working with cardboard tubes, glue, and balsa wood, but also because the space race was in full swing during the later years of the 1960’s. Thus, I built and launched a number of model rockets. A group of us became interested in building our own rocket, not “just one from a kit”. So, we secured a large cardboard tube that carpet came rolled on, and we cut it into about a 4-foot section to make a really big rocket.

FIGURE 1. A more recent rocket flight.

We had been experimenting with a standard rocket fuel of sulfur and zinc. We meas- ured small aliquots (about a square centimeter) to a lid to measure a timed burn. We had

1 having trouble keeping a sustained burn, and the speed of the combustion was disappoint- ing. So, one of us had the idea of mixing the zinc-sulfur with the flash powder that we had perfected earlier. After a few experiments with the burning rate, we were ready to go. We had invented a new rocket fuel. The next step was to fill the tube with the new chemical mixture. The volumes of the components that we needed for the carpet tube rocket were expensive, so we all worked and contributed to the purchase of chemicals for this project. We used an evil-smelling solvent to allow for the even mixture of the components, which we poured into the tube in liter-sized aliquots. We needed to allow the solvent to evaporate between our repeated applications of the same procedure. The evaporation occurred at about the same rate that we earned money to buy more supplies. Anyway, after several trips to the local chemical supply house, we had finished filling the rocket motor compartment in the carpet tube. We packed the fuel around a metal rod down the center of the tube to provide for an empty column through the solid fuel for an even burn. After nearly a week more, the solid fuel had hardened and was ready for the application of fins and a nose cone. We even had grandiose schemes of using a hollow nose cone and launching a mouse. Fortu- nately for the mouse, we did not have time. Anyway, after attaching the fins of heavy cardboard and a solid wooden nose cone, we drove to a launching site outside of Tulsa. After we admired the impressive rocket, we slipped a long piece of dynamite fuse up through the hole in the solid fuel (yes, you could order such things as dynamite fuse through the mail in those days). We made sure that a generous amount of fuse stuck out of the rocket so that we could be well protected in case the fuel exploded. I can’t recall who lit the fuse, but I do remember waiting an eternity until the sputtering flame approached the rocket. The fuel ignited, and a large flame enveloped the whole lower part of the rocket which then began to rise very slowly. Then, it turned on its side and began to fly parallel to the ground, skipping over it in an irregular way. By that time the fins were bent and on fire, too. After it bounced off the ground, rocks, and a tree or two, the prodigal rocket came to rest with its nose cone stuck in the ground at a 45-degree angle. What remained of the crumpled tube billowed smoke and flame until at last, mercifully, only the cardboard was burning. We emerged from our protection cautiously, and advanced slowly toward the wreck. Our initial reconnoiter revealed several of our mistakes - not the least of which was that we started too big, too grand with our first experimental rocket. Also, although we spent much time in our research of rocket fuel, we had spent little to no time on the mechanics of rocket flight and rocket design. After all, the kits had always determined the design. We just assumed that if we made a bigger rocket, it would fly higher than its smaller counterparts. We should have made an effort to learn something about rocket stability. Anyway, I don’t know about the others, but this experience made such an impression on me that I stopped building model rockets altogether for more than 20 years. Had we not given up, one or more of us might have taken the path described by Homer Hickam in Rocket Boys. His group called the “Big Creek Missile Agency” suffered many more pro- found setbacks than we did, but learned from their difficulties. We did not. Our great intentions like our great invention went up in smoke that day in the summer of 1967.

2 BY THE GRACE OF INVENTION Thus we live only by the grace of invention: not merely by such invention as has already been made, but by our hope of new and nonexisting inventions for the future. -Norbert Wiener (1954)

About the same time as the great rocket debacle, my grandfather perfected a locking mechanism that could move easily over a rod, but lock in place with the movement of the hand. This could be applied to music stands, lab stools, and nutcrackers, just to name a few. He applied for and received a patent on the invention, but nothing came of it. I still have the prototype of the nutcracker that produces whole pecan kernels with almost every pull of the lever. All of us in the family were excited about his invention, but the world did not seem to be. Many inventions, even successful ones, are ultimately failures and go up in smoke. Norbert Wiener (1894-1964), an American mathematician who among other things worked on the mathematics of and their applications to rocket guidance systems during World War II, considered the problem of invention and the means to nurture it. He wrote the manuscript of his ideas about invention in 1954, but it languished among his papers until 1993, 29 years after his death. Wiener considered the useful modern inventions to be applications of scientific concepts. Indeed, he did not seem to differentiate between science and technology, but saw them as part of a continuum. Wiener defined four stages in the process of invention: the intellectual, technical, social, and economic stages. He contended that these had to occur in this order for them to be successful, a success based on the invention’s benefit to society rather than to the individual inventor or entrepre- neur. Except for a few outdated examples, and repeated references to the antagonism between the Soviet Union and the United States, Wiener’s ideas are as relevant today as they were in 1954. At its most fundamental level, the intellectual stage is the idea, the concept. The idea of my grandfather’s locking device (and less so for our solid fuel rocket) is the insight in how to solve a practical problem. Here, I refer to the theoretician as the thinker or the person with the idea but not necessarily the means to bring that idea to fruition. By and large, scientists, engineers, and all manner of technicians are used to this type of thinking. Most of their ideas are tossed about and thrown away. Some ideas survive.

FIRE ARROWS, ROCKETS INVENTED Invention is a heroic thing and placed above the reach of a low and vulgar genius. It re- quires an active, a bold, a nimble, a restless min; a thousand difficulties condemned with which a mean heart would be broken. - Thomas Sprat (1667)

The one or ones who first had the idea of the rocket are lost in a time without science, but they seem to have appeared in China, probably not long after the invention of gunpowder. The first Chinese rockets probably evolved from firecrackers made from sec- tions of bamboo stuffed with black gunpowder and were as unpredictable as mine was. Likely, these were thrown into fires to make the explosive bang required during festivals and celebrations. Some probably did not explode, but shot out of the fire as small rockets. Regardless of the particulars, the Chinese repelled the Mongols in 1232 with rocket- propelled arrows, which spat flame and startled their enemies. The fire arrow was a lar-

3 ger version of the bottle rocket that I used as a boy. It had a tube filled with black gunpowder and used a trailing stick as a guidance mechanism (see Figure 2). Anyway, the fire arrows were effective in repelling the Mongols because of the terror that they inspired rather than their accuracy. Wan-Hu, a Chinese official, got the idea that he could fly if he sat in a chair propelled by fire arrows. The story goes that he attached 47 fire arrow rockets to a chair with two large kite-like wings mounted above it. After the arrows were lit, Wan-Hu disappeared forever in a thunderclap of fire and smoke.

FIGURE 2. Fire arrows. The top illustration shows a rocket stabilized by a trailing stick.

The Chinese and Mongols perfected the rocket, in part as a military weapon. How- ever, it saw most use as a means of celebration. Probably, the Mongols carried the knowledge of rockets to the Arabs and Indians who, in turn, introduced the rocket to the Europeans. There, the step rocket or multiple staged rocket was invented. Still, the rocket was a plaything or a weapon for effect. There was little or no scientific basis for rocket design, particularly stability and guidance (both attributes were lacking in my experimental rocket, as well). However it was made, the Chinese rocket had become a successful invention. It began as an idea. Then the technical climate developed through the perfection of gunpowder and materials to construct fire arrows. The social climate for the invention grew as the technical skill of making gunpowder developed and flourished in a caste of artisans who provided the propellant, while others, also thorough trial and error, perfected the fire arrow for maximum effect. Thus, the rocket had gone through the first three of Wiener’s stages of invention. I argue that for large government-funded projects, the economic stage is combined with that of the social stage. The government provides the economic incentive and the framework for the communication between the theoreticians and those with adequate technical skill (technicians). In China, there really were no theoreticians in the modern scientific sense. The rocket worked and developed through trial and error. During the Enlightenment in Europe, scientists (natural philosophers) had gone beyond the science of the ancients. This development, particularly in physics, led to a theoretical framework from which new ideas could arise and provided a common language, one of mathematics, in which theoreticians and technicians could communicate.

4 NEWTON’S LAWS AND ROCKETS Although Newton derived the theories appearing in the Principia over 300 years before the beginning of the space age, they serve as the foundation of modern spaceflight mechanics, more popularly known as rocket science. -Wayne Lee

Isaac Newton (1642-1727) followed the leads of Rene Descartes and Galileo Galilei who envisioned the physical universe as a mechanism with definable mechanical laws. Newton stated three Laws of Motion in his book, Principia Mathematica Philosophiae Naturalis1. His first law was really a statement of motion as defined by Galileo who said that an object continues in its particular state of motion unless it was acted upon by a force. This idea ran counter to those of pre-Galilean philosophers who said that objects remain in motion because they were acted upon by a force. In the earlier view, an object like a ball rolling across a floor, stops moving naturally because the mover’s hand no longer pushed it. Galileo said that the ball would remain in motion and slow down only as it was acted upon by friction. In this case, friction was a force and its action on a rolling ball was to change its velocity. In a more general sense, Galileo said that all objects possessed an “inertia” that kept them moving in uniform motion. For this reason, New- ton’s first law is usually called the Law of Inertia which he defined with these words: “Every body persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it.” In Newton’s view, both a state of constant motion and a state of rest were “natural” and could not be distinguished from each other. If a force is applied to an object, its velocity changes. A change in velocity is called acceleration. So, a force applied to an object causes it to accelerate2. What if the same force is applied to two different bodies like a baseball and a bowling ball? Do they accelerate at the same rate? No, because a force is the product of its mass and its acceleration. The more massive object will have a smaller acceleration (and vice versa). So, the mass of an object is a way of expressing its inertia or tendency to remain in its current state of motion. This is Newton’s second law of motion. Newton’s third law of motion states that forces come in pairs such that for every action there is an equal and opposite reaction. The most common example is that of an in- flated balloon (see Figure 3). When air is allowed to escape, the stream of air is an action that causes the balloon to fly about in reaction. The third law has an obvious connection with model rockets in which its thrust, a force or an action, is the consequence of the con- sumption of propellant and the velocity of the escaping gasses. Thrust then induces a reaction in which the rocket moves in the opposite direction from the escaping gasses. In the case of a model rocket, gasses escape from the nozzle of the rocket engine at about 800 meters per second. [My experimental rocket also did not have a nozzle. However, this is probably fortunate since the confined gasses would likely have exploded.]. In the metric scale, the Newton is a unit of force in which 1 kilogram accelerates at the rate of 1 meter per second per second. Model rocket engines typically specify the total impulse force (Newton-seconds; that is the total force over the length of the burn) by letter followed by a number that indicates the average force in Newtons. For example,

1 Please see Principia Mathematica: The Foundation of Modern Physics for a further discussion of the importance of this text. 2 Note that here acceleration does not mean speed up. It could mean slow down as the force of friction on a rolling ball.

5 a C6 rocket engine produces a total impulse of 5-10 Newton-seconds and an average force of 6 Newtons (see Table 1 for standard model rocket engines). So, a rocket that has a mass of 25 grams (with the rocket engine) has higher acceleration with the same rocket engine than does a rocket with a mass of 100 grams. In fact, the smaller rocket should accelerate four times faster than the larger one. Greater acceleration means greater alti- tude in the case of rockets.

A. DIAGRAM OF A BALLOON

B. DIAGRAM OF A ROCKET FIGURE 3. Balloons and rockets both obey the third law of motion. A. shows the paired forces on a balloon. The force of the air leaving the balloon causes it to travel forward. B The paired forces on a rocket.

TABLE 1. The code used on rocket engines and its meaning in average thrust. CODE Newton-seconds ¼ A 0.000 – 0.625 ½ A 0.625 – 1.250 A 1.250 – 2.500 B 2.500 – 5.000 C 5.000 – 10.000

6 Newton’s laws of motion began to be used by engineers to perfect the rocket in Ger- many, Russia, and Britain where applications of Newton’s laws allowed for larger and more stable rockets. A British artillery officer, Colonel William Congreve at the turn of the 19th century, observed the effect of fire arrows in the hands of Indian nationals during Britain’s conquest of India. He realized that rockets could provide massive firepower that would exceed that of the muzzle-loading cannon of the day. His invention, called the Congreve rocket, was successful militarily and was employed by the British in many campaigns. In fact, Congreve’s rockets were used in the siege of Fort McHenry and prompted Francis Scott Key to include the phrase, the rockets’ red glare in the poem that would later become the words of our national anthem. Rockets were useful in that thou- sands of them could be fired upon an enemy without heavy artillery pieces and the delay that muzzle loading required. Later, that advantage began to disappear with the advent of breech-loading cannons. Also, cannons were much more accurate than rockets. A few improvements allowed slightly increased control over where a rocket went, but it still required a good bit of luck to hit an intended target. Much earlier, fins had re- placed the stick of the fire arrow. In the 19th century, fins were placed in the nozzle, the bell at the back of Figure 3-B. These fins were angled slightly to cause the rocket to spin. A spinning rocket was more stable and tended to go in a straighter line. Other engineering aspects of rockets began to be known. For example, there is a point on a rocket at which the mass in front equals the mass in back. This is called the center of mass or center of gravity. A rocket tends to rotate, tumble, or oscillate about the center of gravity, just like a stick does when it is thrown. Similarly, a model rocket tumbles if it has no fins. With fins a rocket functions like a weather vane. As it picks up speed, and slices through the air, the fins hold it steady. That is why the fins are at the back of the rocket. As air moves past the rocket, drag is created by friction. This is (in an aerodynamic design) related to the surface area of the rocket. The greater the surface across which air must travel, the greater its drag. Like the center of gravity, a rocket has a point called the center of pressure about which the surface area in the front equals the surface area in the back. A rocket is stable when the center of pressure is well back of the center of gravity. That is why fins must be at the back of the rocket. Aerodynamic design is useful for any object that travels through the atmosphere at high speed. However, some dreamers began to think of moving at high speed beyond our atmosphere into the unknown reaches of space. The first dreamers were science fiction writers like Jules Verne and H.G. Wells. While some had their characters explore space with balloons, and all manner of exotic devices to fling the human-bearing craft into space, H.G. Wells in The First Men in the Moon employed antigravity. Jules Verne was more straightforward and shot his characters from an enormous cannon in Florida. Al- though these particular methods were hopelessly counter to natural law or common sense, both of which science fiction writers seem to avoid at all cost, the dream of travel through space and to other worlds began. This inspiration in the age of technical growth through the application of Newtonian physics, gave rise to a collection of inventors with the goal of space exploration.

7 A DEAF TEACHER All men dream; but not equally. …The dreamers of the day are dangerous men for they may act their dream with open eyes to make it possible. -T. E. Lawrence; The Seven Pillars of Wisdom

Among the dreamers of the day, none was more important in laying the scientific foundation for space exploration than Konstantin Eduardovich Tsiolkovsky (1857-1935). Born near Moscow in the Russian Empire, he grew up in a family of 17 brothers and sis- ters. When he was 10, Tsiolkovsky was stricken by scarlet fever and lost his hearing as a consequence. Being deaf, he could no longer attend school so he taught himself by reading. Later, the Russian philosopher and proponent of space exploration, Nikolai Fedorov, tutored him. Besides the influence of Federov, Tsiolkovsky said that he was inspired by the influence the novels of Jules Verne to produce vehicles for living in space, not just travel. Tsiolkovsky passed exams to earn a teaching certificate and began to experiment with balloon design. During this time, he realized that the only mechanism with the force necessary to allow humans to escape the earth was the rocket. This was no small step to take. The conventional wisdom of the day concerning Newton’s third law and rockets was that a rocket moved forward by pushing against the air. Because there was no air in the vacuum of space, a rocket could not work there. Tsiolkovsky realized that the thrust came from the velocity and mass of the escaping gasses, thus a rocket would work even more efficiently in a vacuum. Tsiolkovsky published this concept in 1903 as his rocket equation that he derived from Newton’s laws (see Figure 5).

FIGURE 4. Konstantin Eduardovich Tsiolkovsky as a young man.

8 u = v ln (M0 / M) + u0 FIGURE 5. Tsiolkovsky’s rocket equation. u is the final velocity of the rocket; v is the velocity of the exhaust gasses; M0 is the initial mass and the M is the final mass; u0 is the initial velocity.

Tsiolkovsky attacked the problems of rocketry and human habitation in space from a theoretical point of view. He determined that solid fuel rockets were not very practical for use in space. For one thing, solid fuels were heavy compared to the thrust that they produced. Liquid fuels were much more efficient and allowed for the speeds necessary to escape the gravitational pull of the earth (called escape velocity). In addition, solid fuel rockets could not be controlled after ignition because, once lit, they burned to the end. Liquid fuel rockets could be ignited, stopped and ignited again and again. This kind of control would be necessary to navigate in space. Tsiolkovsky set about designing liquid fuel rockets, multiple stage rockets, air locks, etc. Unfortunately, all of his work was theoretical. He was not able to build and test any of his designs until much later in life. Still, as a scientist he was prolific and published more than 500 articles on the theory of rocketry and space flight.

FIGURE 6. Tsilokovsky’s rocket designs published in 1903.

ROCKETS IN PRACTICE As I looked toward the fields to the east, I imagined how wonderful it would be to make some device which had even the possibility of landing on Mars, and how it might look on a small scale if I sent it up from the meadow at my feet. -Robert H. Goddard, from Clarke (1968)

Robert Hutchings. Goddard (1882-1945), was born in Massachusetts and, like Tsi- olkovsky, was inspired by the science fiction of H. G. Wells and Jules Verne and inde- pendently arrived at the need for a liquid fuel rocket to explore space. Unlike Tsiolk- ovsky, however, Goddard began to build and test rocket designs [One early design nearly blew up a physics lab at Clark University in 1907 while he was a student. Fortunately, he

9 was not expelled.] Thus, he was not only a theoretician, but used and developed necessary technical methods, materials, and machines. Goddard funded himself and acquired two patents for rocket design in 1914 (a liquid fuel rocket design and a design for a multistage solid fuel rocket). Later, he received funding from the Smithsonian Institution in 1916 to continue his work. In 1920, Goddard submitted a report to the Smithsonian Institution detailing his experiments and how money was spent. Toward the end of the report, he suggested that a rocket could be built and fired at the moon with a payload of flashpowder. Upon its arrival, its explosion could be detected by telescopic examination. The press picked up this last part of his report and ridiculed him. After that experience, Goddard remained somewhat secretive and refused to join or communicate with the American Rocketry Society. On the morning of March 16, 1926, Robert Goddard flew the first liquid fuel rocket at his aunt’s farm in Auburn, Massachusetts. The rocket flew only 152 feet high (about the same distance as the first flight of the Wright brothers 13 years earlier). Following that, Goddard’s practical achievements were many. He demonstrated Tsiolkovsky’s assertion that a rocket would work in a vacuum. In 1929, he sent aloft a barometer and a camera as the first scientific payloads. He built and developed the use of gyroscopic control and guidance of rockets, and in 1937, he launched a liquid fuel rocket that was guided by gyro-controlled gimbals.

FIGURE 7. Goddard with the first working liquid fuel rocket.

In 1936, Goddard published an account of his work through the Smithsonian Institu- tion. Although he worked for the U.S. Navy during both World Wars and accumulated

10 more than 200 patents on rocket design, Goddard’s work and its potential was ignored by the U.S. military. However, his work was not ignored by his counterparts in Germany.

A DOCTOR DENIED Never mind. I will prove that I am able to become a greater scientist than some of you, even without the title of doctor. -Hermann Oberth

Hermann Julius Oberth (1894-1989) was born in Romania and became interested in space travel, like Tsiolkovsky and Goddard, after reading Jules Verne’s From the Earth to the Moon. After service in the medical corps during World War I, he continued his studies at the University of Munich. His experience during the war convinced him that he did not want to be a physician so he began to study physics. His dissertation in 1922 on the use of rockets for space travel was rejected because the old-school German physi- cists could not accept that a rocket would work in the vacuum of space. Discouraged but not defeated, Oberth did not try to write another dissertation, but continued his interest in rocketry. In 1923, he reworked his dissertation and published it as The Rocket into Planetary Space. He published a much longer version in 1929. As an impoverished teacher of mathematics, Oberth, like Tsiolkovsky, was unable to fund the application of his ideas. However, he helped to found the German Rocket Soci- ety which raised money to fund the research and development of their rockets. Unlike the secrecy of Goddard’s work, the rocket society held highly publicized launches. In 1932, a Captain Dornberger of the newly organized German Army witnessed one of the public launches. A few months later the society disbanded as its members began to work for the German military. Werner von Braun (1912-1977), inspired by Oberth’s writings, worked as Oberth’s assistant from 1930-32. Thereafter, von Braun, who always referred to Oberth as “my teacher”, became the leader of the military rocket research program. Later, they worked together again during World War II in the construction and development of the venge- ance weapons (the V1 and V2). The V2 was a larger and improved version of the rocket built by Goddard in 1937, and, fortunately, it was deployed too late to have an influence on the outcome of the war. After the surrender of Germany, the U.S. which had all but ignored the work of Goddard, brought both Oberth and von Braun to the U.S. to get our program off the ground. The Soviet program under the influence of the followers of Tsi- olkovsky was alive and well at the time. The inventions associated with rocketry mounted through the 20th century. In this process, invention supported invention. The technical foundations already laid in physics, chemistry, metallurgy, mechanical engineering, etc., allowed the development of components of rockets that made them more reliable, more stable, and more accurate. The giant Saturn V, the rocket that carried the Apollo program to the moon was the crowning achievement of von Braun and, thereby of Oberth, Goddard, and Tsiolkovsky.

FIGURE 7. Oberth (left) and von Braun.

A TRINITY God loves a trinity. -A Russian Proverb

A Russian proverb says that God loves a trinity. That is, important things come in threes. Isaac Newton defined a trinity of laws that gave a scientific basis to rocketry. Three 20th century scientists with dreams of human space exploration and Newton’s laws saw rockets as necessary means to those ends. Often working in isolation from the rest of the scientific community and from each other, they taught others who carried on their quest. Of the three, only Oberth witnessed a human presence in space. The steps required for human entry into space were painful and, at times, faltering. There were many missteps, many failures as in the history of powered flight. Indeed, my misadventure with a rocket pales next to some of the rocket-related disasters. Fortu- nately, the climate of invention supported the growth of dreams into practical ideas. These, in turn, spawned more ideas until the development of the space shuttle, the most complex machine ever devised. However, it is only the last in a developing set of machines produced through the trinity of science, technical advance, and ideas. The shuttle is just a step in the path to the stars, for as long as there are dreamers, the ideas will not cease to fly. On April 12, 1961, the dreams of Tsiolkovsky, Goddard, and Oberth took flight after cosmonaut Yuri Gagarin sitting in a space capsule atop a rocket called out “Поехали! (Let's go!)” -Revision of essays written in 2000 and 2002

Sources that I used to write the essay: Clarke, Arthur C. 1968. The Promise of Space. Pyramid Books. New York. Halliday, David and Robert Resnick. 1970. Fundamentals of Physics.. John Wiley and Sons, Inc. New York. Hickam, Homer H. 1998. Rocket Boys. Delta Books. New York. Kosmodemyansky, A. 2000. (from 1954 edition). Konstantin Tsiolkovsky, His Life and Work. University Press of the Pacific. Honolulu, Hawaii. Lee, Wayne. To Rise From Earth. Facts On File, Inc. New York. NASA. Robert H. Goddard: American Rocket Pioneer. NASA FACTS. http://pao.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/general/goddard/goddard.ht m

12 NASA. A Brief History of Rocketry. NASA Spacelink. http://www.ksc.nasa.gov/history/rocket-history.txt Rosenberg, Carla, editor. 1996. Rockets, A Teacher’s Guide with Activities In Science, Mathematics, and Technology. NASA. EG-1996-09-108-HQ. Wiener, Norbert. 1994. Invention, The Care and Feeding of Ideas. MIT Press. Cam- bridge, Mass. Internet Sources: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html http://deathstar.rutgers.edu/museum/tsiol.html http://strange.simplenet.com/oberth/ http://www.allstar.fiu.edu/aero/Rock_Hist1.html http://www.magicnet.net/~westham/tp12.html http://www.philately.com/space/foundations_space_travel.htm http://www.uh.edu/engines/epi515.htm

Questions to Think About

1. Think of at least one reason why the carpet tube rocket went out of control. 2. Who was Norbert Wiener and what were his four stages in the process of invention?

3. Where were rockets invented? What were they used for? 4. Who was Wan-Hu and what was his fate? 5. What is a difference between the science of the ancients and the science of the Enlightenment? 6. What is Newton ’s First Law? Who really defined it as a law of motion? 7. What is Newton ’s Second Law of Motion? 8. Newton ’s Third Law of Motion usually is the one applied to the principles of rocketry, why? 9. What is the difference between center of mass and center of pressure? How should they be related to make a stable rocket? 10. Who were the writers most responsible for igniting the dreams of 20th Cen- tury rocket inventors and engineers? 11. Who was Konstantin Eduardovich Tsiolkovsky and what did he contribute to rocket technology? 12. Who was Robert Hutchings. Goddard and what did he contribute to rocket technology?

13. Who was Hermann Julius Oberth? How did he indirectly influence the US space program? 14. Who was the first person to make the dream of human spaceflight come to fruition?