Beyond: Our Future in Space

by Chris Impey

  Figure 4. Wan Hu was a legendary Chinese government official of the middle Ming Dynasty (sixteenth century) who tried to become the world’s first astronaut by attaching forty-seven rockets to a specially constructed chair.

  Rather than becoming China’s first astronaut, Wan Hu was probably obliterated from the explosive force of so many rockets detonating simultaneously. Despite this spectacular failure, the Middle Kingdom was far ahead of other countries in developing rockets, beginning a long tradition that twinned rocketry with warfare.

  The earliest uses of rockets are poorly documented. There are reports that the Greek philosopher Archytas, who speculated about the edge of space, amused the citizens of Tarentum in southern Italy by moving a wooden bird through the air suspended on wires. The propulsion mechanism was escaping steam. The first true rockets were probably accidents. In the first century AD, the Chinese learned how to make simple gunpowder from saltpeter, sulfur, and charcoal dust.2 They put this mixture into bamboo tubes and tossed them into a fire to make explosions during religious festivals. Some of the tubes may have failed to explode, instead skittering out of the fire propelled by gas from the burning gunpowder.

  The word rocket appears as early as the third century, during the Three Kingdoms period. Soldiers had learned to attach bamboo tubes filled with gunpowder to arrows, light them, and then launch them with bows. In 228, the Wei State used this kind of “fire arrow” to defend the city of Chencang from the invading forces of the Shu State.

  Over the next few centuries, rockets continued to appear in harmless fireworks celebrations, but they showed more promise as military weaponry. The Chinese discovered how to make rockets that could launch themselves. A tube holding gunpowder was capped at one end, with space for a slow-burning fuse, and the other end was left open. The tube was attached to a stick to provide stability and a crude guidance system. When ignited, the outrushing gas from this solid-fuel rocket produced a large forward thrust. Such rockets were first used in battle by the Chinese in 1232 to repel Mongol invaders.3 Although they weren’t effective as weapons of destruction, one can only imagine the psychological effect of being on the receiving end of a barrage of “arrows of flying fire.”

  Soon, other cultures began their own experimentation and implementation. The Mongols adopted rockets and hired Chinese rocket experts as mercenaries, who helped them conquer Russia and parts of Europe. They used rockets to capture Baghdad in 1258. Quick to learn, the Arabs used rockets ten years later to help defeat Louis IX of France between the Seventh and Eighth Crusades. Europeans soon learned its secrets and started to improve the technology.4 Roger Bacon discovered the optimum formula for gunpowder: 75 percent saltpeter, 15 percent carbon, and 10 percent sulfur. This recipe was more explosive than Chinese recipes and gave rockets greater range.

  Early rockets were so unreliable they could only be used to confuse and frighten the enemy. As the chemistry of gunpowder matured, however, rockets began to influence the outcome of battles. It was the world’s first arms race.

  The Chinese continued to create new and complex rockets throughout the Ming Dynasty, when even a great seafaring nation like China suffered many thefts and losses due to piracy. To fight the pirates, General Qi Jiguang used hardwood for the body of the rocket and had armor-piercing swords or spears at the front end. He put more than 2,000 rockets on ten warships and developed multishot rockets that allowed up to a hundred of the devices to be launched simultaneously with a single fuse. Other innovations were multistage rockets that could fly for several miles over water and rockets with reusable tubes. General Qi used all of these methods to defend the Great Wall from the Mongols.

  The Chinese were first to develop gunpowder and rockets, and during medieval times they were able to keep invaders at bay with formidable arsenals, but their science was based on experimentation with no corresponding development of theory. In the late thirteenth century, mathematician Yang Hui noted: “The men of old changed the name of their methods from problem to problem, so that as no specific explanation was given, there is no way of telling their theoretical origin or basis.”5 Ironically, the stability of Chinese civilization worked against innovation. With a strong central government and stifling bureaucracy, there was little incentive to try something new. Europe, meanwhile, suffered a series of famines and plagues that put an end to growth and caused social upheaval. The Renaissance and the Scientific Revolution emerged from this chaos and propelled Europe to great prosperity.

  Ultimately, neglect of science and technology caused the Chinese to lose their edge. By the late fourteenth century, Europe had caught up. For warfare, Europeans developed and perfected the smooth-bore cannon. Rockets were relegated to firework displays.6 Wan Hu’s dreams of traveling to the stars were forgotten.

  They were given a firm theoretical basis in the work of Isaac Newton, the author of a theory of gravity and laws of motion that would be the basis for space travel centuries later. Newton’s 1687 masterwork, Principia, unified the terrestrial and celestial realms. Drop an apple and it falls in one second 3,600 times farther than the Moon curves in its orbit, both caused by the action of the Earth’s gravity. He described a “thought experiment” where a cannon points sideways at the top of a mountain high enough to be above the atmosphere. With no friction or air resistance, the only force operating is gravity.7 Fired at modest speed, the cannonball will land at the base of the mountain. As the initial speed is increased, the ball travels farther and farther before landing. Newton calculated the speed where the ball falls toward the Earth’s surface at the same rate as the Earth’s surface is “falling away” from it (Figure 5).

  Figure 5. In the thought experiment of Isaac Newton, a cannonball is launched horizontally from a mountain tall enough to be above the Earth’s atmosphere. As the velocity increases, the surface curves at the same rate the cannonball falls, creating a circular orbit.

  This is the concept of an orbit. Any projectile shot from Newton’s hypothetical cannon at 7.9 kilometers per second or 17,650 mph would remain a captive of the Earth’s gravity but would never hit the ground. At over 11 kilometers per second or just over 25,000 mph, the projectile would be liberated from the Earth forever.

  The Visionaries

  Konstantin Eduardovich Tsiolkovsky was an unlikely rocket scientist. In 1857, he was born into an impoverished family of Polish immigrants in a small Russian town, the fifth of eighteen children. At the age of ten, he developed scarlet fever, leaving him deaf and isolated. By the age of fourteen, his mother had died and he had given up formal schooling.

  A reclusive teenager, he moved to Moscow so he could spend long hours at a local library, where he studied physics and astronomy. At the library he was influenced by Nikolai Fyodorov, a futurist who advocated radical life extension and immortality and who thought that the future of humanity lay in space. He also stumbled on the works of Jules Verne and became inspired by Verne’s tales of space travel. Tsiolkovsky’s family recognized his talent but worried that he was studying obsessively and forgetting to eat. When he was nineteen, his father brought him back home and helped him get a teaching credential so he could earn a living.

  Tsiolkovsky became a math teacher in a small provincial school outside Moscow. In his spare time he wrote science fiction, but soon he became more interested in the concrete problems of space travel. He realized that passengers would not survive the acceleration forces of a cannon, the method Jules Verne imagined to get travelers to the Moon. He was far from any center of learning, so when he tried to publish his work on the kinetic theory of gases, a friend had to point out that those ideas had been published twenty-five years earlier. Even as a teenager, Tsiolkovsky had constructed a centrifuge to test the effects of strong gravity. Chickens procured from local farmers were his test subjects. Later, he built the world’s first wind tunnel in his apartment and conducted experiments on the aerodynamics of spheres, disks, cylinders, and cones. But he had no funding for his research and he was isolated from the scientific co
mmunity, so most of his insights were theoretical.

  In 1897, however, Tsiolkovsky had an insight that underlies all of space travel today.

  He devised an equation relating the change in mass of a rocket to its exhaust velocity. He recognized the critical role of a nozzle in forcing the gas out at high velocity, and he predicted the need for multistage rockets to overcome the Earth’s gravity. He also designed fins and gas jets to control the trajectory, pumps to drive fuel into the combustion chamber, and mechanisms that used propellant to cool the rocket in flight. His fertile mind came up with designs for dirigibles, metal jet aircraft, and hovercraft. Hearing about the newly constructed Eiffel Tower triggered the idea of a space elevator as a way of getting into orbit without a rocket.9

  This Russian visionary continued to face adversity.10 A year before he developed the rocket equation that bears his name, Tsiolkovsky’s son committed suicide. Eight years later, a flood destroyed most of his papers. Three years after that, his daughter was arrested for engaging in revolutionary activities.

  In 1911 he wrote: “To place one’s feet on the soil of asteroids, to lift a stone from the moon with your hand, to construct moving stations in ether space, to organize inhabited rings around Earth, Moon and Sun, to observe Mars at the distance of several tens of miles, to descend to its satellites or even to its own surface—what could be more insane!”11 His work took all these ideas from unreal fantasy to the brink of reality.

  Tsiolkovsky was sustained in his work by a philosophical and spiritual movement called cosmism. In Russia, one of the foremost proponents of cosmism was Nikolai Fyodorov, whom Tsiolkovsky had met at the library. They shared a utopian belief that the future of humanity was to spread into space and conquer disease and death. Cosmism emerged after the Russian Revolution, envisaging a heroic image of the proletarian who strides forth from the Earth to conquer planets and stars.12 One quote epitomizes Tsiolkovsky’s views on space: “The Earth is the cradle of humanity, but mankind cannot stay in the cradle forever.”

  In the 1920s, the young physicist Hermann Oberth was unaware of Tsiolkovsky’s work, but he too dreamt of space travel. Like the Russian, Oberth was inspired by Jules Verne, rereading the novels to the point of memorization. He dabbled with rockets as a child and by 1917 his expertise had grown such that he fired a rocket with liquid propellant as a demonstration for the Prussian minister of war.13 His doctoral thesis, “The Rockets to the Planets in Space,” later became an essential contribution to rocket science, but initially it was rejected. Oberth was fiercely critical of the German education system, saying it was “. . . like an automobile which has strong rear lights, brightly illuminating the past. But looking forward, things are barely discernible.”14

  Like Tsiolkovsky, Oberth worked outside academia for the majority of his career, earning a living as a schoolteacher. He was a leading member of the “Spaceflight Society,” a German amateur rocketry group whose members scavenged any materials they could find for their rockets as Europe descended into an economic depression. In 1929, Oberth was a technical adviser to the film pioneer Fritz Lang for Woman in the Moon, the first film ever to have scenes set in space. He lost an eye during a publicity stunt for the film. That same year, he conducted a captive firing of his first liquid-fueled rocket engine. One of his assistants was eighteen-year-old Wernher von Braun, who would later feature prominently in our efforts to reach space.

  The first to launch a liquid-fuel rocket was American Robert Goddard. As a boy, Goddard was thin, frail, and subject to pleurisy, bronchitis, and stomach problems. He spent much of his time holed up in the local public library, where he was transported by the science fiction of H. G. Wells. Goddard fixed his inspiration to a day when he was seventeen and he climbed a cherry tree to remove dead limbs: “I imagined how wonderful it would be to make some device which had even the possibility of ascending to Mars, and how it would look on a small scale, if sent up from the meadow at my feet. . . . I was a different boy when I descended the tree from when I ascended.”15

  In 1914, Goddard registered the patents for a liquid-fuel rocket and a multistage rocket, the first of his more than two hundred patents. He was a hands-on experimenter as well as an expert physicist. Liquid-fuel rockets are finicky because the volatile fuel and oxidizer must be injected into a combustion chamber at a carefully controlled rate. On a bitterly cold spring morning in 1926, Goddard achieved success with a small liquid-propellant rocket dubbed “Nell.” Launched from his Aunt Effie’s farm, it traveled for 184 feet in a flight that lasted less than three seconds, landing in a cabbage field (Figure 6). Over the years, he conducted more than three dozen test flights, refining his designs and techniques until he reached altitudes of several miles. In 1929, he began what became a lifelong friendship with Charles Lindbergh, who shared his vision.16

  Figure 6. Robert Goddard is bundled against the cold of a New England winter in 1926 as he stands by the launching frame of his most notable invention. The liquid fuel of this rocket was gasoline and liquid oxygen, contained in the cylinder across from Goddard’s torso.

  Nevertheless, the world was not quite ready for rockets. Goddard’s seminal paper from 1919, “A Method of Reaching Extreme Altitudes,” was ridiculed by the press and fellow scientists. An unsigned editorial in the New York Times was particularly harsh, accusing him of ignorance of the laws of physics: “. . . Professor Goddard . . . does not know the relation of action and reaction, and of the need to have something better than a vacuum against which to react. . . . Of course he only seems to lack the knowledge ladled out daily in high schools.”17 Forty-nine years after ripping Goddard, and a day after the launch of Apollo 11, the paper issued a brief correction: “Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.”18 The apology was too late for Goddard, who died of throat cancer in 1945.

  Wernher von Braun

  Warfare and space exploration merged again in the 1940s. Goddard had financed his research with small grants from the Smithsonian Institution and the Guggenheim Foundation; no government agency showed interest and the military was particularly dismissive. But America’s future adversaries were very interested in Goddard’s rocketry. During the 1930s, a German military attaché working in the United States sent a report on Goddard’s work back to the military intelligence agency, and the Soviets gleaned information from a KGB spy embedded in the US Navy Bureau of Aeronautics. Toward the end of World War II, Goddard got to inspect a captured German V-2 ballistic missile. The V-2 was far more advanced than any of Goddard’s rockets, but he was convinced the Germans had “stolen” his ideas. In particular, Goddard was furious at Oberth, whom he accused of plagiarizing his 1919 work; this episode contributed to Goddard’s secrecy and paranoia.19

  The architect of the V-2 was the most controversial figure in the history of rocketry: Wernher von Braun.

  We can picture the young German boy as he became hooked on rockets. Inspired by Germans who were setting land speed records in rocket-propelled cars, the twelve-year-old caused major disruption in a crowded street. Echoing Wan Hu, he attached to a toy wagon a dozen of the largest skyrockets he could find. Rather than riding the wagon as Wan Hu had ridden his sedan chair, von Braun lit the fuses and stood back. He was thrilled with the results: “It performed beyond my wildest dreams. The wagon careened crazily about, trailing a tail of fire like a comet. When the rockets burned out, ending their sparkling performance with a magnificent thunderclap, the wagon rolled majestically to a halt.”20 The police who arrived on the scene were less impressed; they took the young boy into custody.

  Wernher von Braun was rescued from that indiscretion by his father, who was the German minister of agriculture. His mother could trace her ancestry back to the kings of France, England, and Denmark, and the young von Braun inherited the title of baron. All through his life, he exhibited a self-
confidence bordering on arrogance.

  Though he was a gifted musician who played piano and cello and composed in the style of Hindemith, von Braun initially struggled with math and physics. His mother bought him a telescope, allowing him to be captivated by the Moon. As a young teenager, he bought By Rocket into Interplanetary Space by Hermann Oberth but was dismayed when he opened it. He recalled, “To my consternation, I couldn’t understand a word. Its pages were a baffling conglomeration of mathematical symbols and formulas.”21 He realized that the success of space travel was underpinned by technical calculations, so he decided to master the relevant subjects. At the age of eighteen, he began his long tutelage with Oberth; that same year, he attended a talk by a pioneer of high-altitude ballooning, telling him, “You know, I plan on traveling to the Moon at some time.”

  When Adolf Hitler came to power, Wernher von Braun was twenty-one. He later claimed that he had been apolitical and disinterested in the world around him. But his uncritical patriotism meant that, at best, he was surprisingly naïve about the ramifications of his work and, at worst, he was complicit in death and destruction.22

  With the joy of an amateur, von Braun continued to experiment with rockets. His days in Berlin were busy with study toward a graduate degree in physics, but he spent every spare moment at a derelict, 300-acre site of scrub and weeds at the edge of the city. There, members of the Berlin Rocket Society carried out their work using scrounged materials and donated labor. When the Army Ordnance Department took interest and started to fund their research, von Braun was delighted. (It was in fact exactly the type of military support that Goddard had sought and failed to get for his own work.) When von Braun finished his thesis in 1934, parts of it were considered so crucial to national security that they stayed classified until 1960. He set aside his dreams of space travel and moved to a big facility that the Army built for him on an island in the Baltic Sea. There he worked on a weapon the Nazi Propaganda Ministry would eventually call the Vengeance Weapon 2, or the V-2 (Figure 7).