Breaking the Chains of Gravity Page 2
The sailplane Valier eventually procured was a specially modified Lippisch Ente (which means “duck” in German), a moniker derived from the plane’s long, beak-like structure jutting out front. In place of the absent tail were two cylindrical rockets packed with nearly nine pounds of compressed black powder that were wired to be electrically ignited from the pilot’s seat. In the cockpit on the morning of June 11, 1928, was one of Lippisch’s company test pilots named Friedrich Stamer. As Valier had done with the rocket cars, Stamer got the Ente flying before lighting the rockets one at a time. A quiet hissing told him the first rocket was burning; for the moment there was no significant speed increase to disrupt the easy flight. Seconds later, the hiss was replaced by a booming explosion. In an instant the Ente was on fire. Without succumbing to panic, Stamer managed one of the finest landings of his career to that point, getting the flaming plane to the ground before the second rocket had a chance to ignite. Only once he was on the ground did the pilot react with panic. He wriggled out of the plane and rolled in the wet grass to extinguish and soothe his own rear end while the Ente’s burned. Stamer walked away from the flight unharmed. Unfortunately, the same could not be said for the plane.
Years of mixed results in testing rocket-powered automobiles, sleds, and sailplanes all fed into Valier’s ultimate dream of using rocketry to shrink the world. He imagined a future where people would cross the Atlantic Ocean from Europe to America in under an hour thanks to rocket propulsion. And from there, he pictured rockets propelling planes higher and faster to the point where they could escape the Earth’s atmosphere to fly in space. But he knew this dream could never be a reality if he didn’t move away from the black powder rockets he had been using in his public demonstration tests. Powder simply couldn’t deliver the power needed to send an airplane rocketing across an ocean or into space. For that, he would need liquid propulsion, and he sought to bring more minds to bear on the challenge of developing this science.
In the back parlor of an alehouse in Breslau on June 5, 1927, Valier met with a small cohort of rocket enthusiasts, scientists who also wanted to bring this fantastical idea firmly into the realm of reality. The group, all drawn to the rockets described in Oberth’s Die Rakete, founded the Verein für Raumschiffahrt (Society for Space Travel) that afternoon with the goal of actually building the rockets described by their icon. Their ultimate goal was summed up in their simple motto: “Help to create the spaceship!”
Oberth joined the VfR in 1929, following an invitation from Valier, one of the last letters between the two men before disagreements over how to approach rocket testing led to their falling out. By then, the society’s roster had swelled to more than eight hundred members, from writers to engineers to scientists. And many, like Oberth, found Valier’s methods more frustrating than fruitful. Though the popularity of his experiments was certainly good for exposure and patronage, most felt Valier’s showmanship denigrated what they were trying to do, turning rocketry into a sideshow rather than a serious field of science. Though he was a founding member, a rift soon developed between Valier and the VfR. It widened until rocketry’s greatest cheerleader left the society he’d founded.
The same year Oberth joined the VfR he released an expanded version of his published thesis. The new book, retitled Ways to Spaceflight, was more than four hundred pages long and secured Oberth’s place as a legitimate rocket scientist. This edition was far more readable, using stories of flights to the Moon to illustrate difficult concepts, and expanded discussions that answered questions critics had raised after reading the earlier edition. The new book also brought six years of additional research to the discussion, covering topics such as optimal flight trajectories for rockets carrying payloads off the planet. Launching a rocket straight up was instinctual but inefficient, Oberth wrote. It was similar to what Valier found with his first rocket car experiments, only this time it was friction with the air and not asphalt that would hinder the rocket. When traveling directly through the atmosphere, the air would drag on the rocket, costing precious energy. It would be better, Oberth suggested, to launch a rocket on an easterly path, allowing it to use the centrifugal force of the Earth’s rotation for a slight increase in speed that would make up for the speed lost through atmospheric friction.
Oberth’s expanded work reached well beyond his scientific peers and into the realm of artists, catching the attention of Fritz Lang. The acclaimed silent film director had debuted his eleventh directorial effort, Metropolis, four years earlier to great fanfare. The film, which tells the grisly story of a futuristic world where subterranean slave labor powers the lives of the rich who live aboveground, entranced audiences. Building off that success, Lang sought to capitalize off the national interest in rocketry. Lang’s wife, Thea von Harbou, had written a script about an intrepid crew who fly to the Moon to confirm an aging doctor’s theory that its mountains hold more gold than any reserves on Earth. In bringing von Harbou’s story to life, Lang wanted the film, Frau im Mond (Woman in the Moon), to balance the fantastic plot with technical accuracy. And so he hired Oberth as the film’s technical adviser.
The prospect delighted Oberth; he knew a realistic movie about rockets would not only popularize the field, it might bring in money for research as well. The physicist threw himself into the project, advising Lang on practical aspects like the size and architecture of the rocket as well as a realistic depiction of the best trajectory for a flight to the Moon. Though Lang exerted his artistic license over Oberth’s technical direction, the film was nevertheless the first to depict a realistic rocket leaving the Earth. In the launch scene, Lang shows the massive rocket crawling along rails from its assembly building to the launch site while searchlights sweep over its impressive structure. Once at its destination, the rocket is lowered into a tank of water, covering it almost to the nose—a means to absorb the vibrations and acoustics of the fiery launch. The rocket’s engines ignite, bubbling the water away as it shoots upward toward the Moon to the delight of the gathered crowd watching from nearby bleachers.
Though Oberth was certainly pleased to have a hand in advising the technical aspects of Frau im Mond, it was a spin-off from this project that really excited the scientist. Willy Ley, a fellow member of the VfR and avid rocket popularizer, suggested that Oberth build and launch a real liquid-fueled rocket to coincide with the film’s release. It could not be a rocket large enough to go to the Moon as in the film, but it would be an incredible publicity stunt. The film company, Universum Film-Aktien Gesellschaft, and its marketing department backed the idea and granted Oberth a small amount of funding. There was, however, one condition. UFA stipulated that Oberth had to pay the company 50 percent of any future proceeds he might make from the technology he developed in building this rocket.
Potential future profits weren’t on Oberth’s mind when he brought fellow VfR member Rudolf Nebel on board and began designing his rocket. Its power source was a liquid-fueled engine of his own design that burned a mixture of liquid oxygen and gasoline. But turning his theory, calculations, and thought experiments into a viable flying rocket turned out to be far easier said than done. His choice of fuel turned out to be a tricky mix. One propulsion experiment had him observe the behavior of a fine stream of gasoline as it was introduced into a container filled with liquid oxygen. The mixture was lit as it would be inside the rocket’s combustion chamber, but the reaction became explosive. The blast burst Oberth’s eardrums and burned the skin around his left eye, nearly costing him the organ. Gasoline and liquid oxygen, the physicist learned that day, combust considerably faster in a limited, narrow space.
Unfortunately, Oberth’s progress was slower than he had anticipated, and he couldn’t meet UFA’s planned launch day of October 29, 1929. The company issued a simple press release in advance of Frau im Mond’s premiere explaining that the launch had been canceled due to unfavorable weather. It was an entirely fabricated excuse, but the public wouldn’t know the difference, and it saved Oberth a considerable amo
unt of embarrassment, though he was not immune to the sting of failure. The film was incredibly well received at its October 15 premiere, but while the social, intellectual, and political elite praised Lang for creating another masterpiece, Oberth was all but ignored. Disillusioned and broke, he left Berlin for Romania to rejoin his family.
A few months later, a new opportunity arose to lure Oberth back to Germany. Nebel had secured funding from the government-sponsored Reich Institute for Chemistry and Technology, and with this influx of money the VfR hoped to bring Oberth’s rocket to life. Oberth consented to return after Nebel’s persistent imploring invitations, and this time he set to work with a larger team plucked from the VfR. He recruited Klaus Riedel, an engineer from the Siemens Company, which manufactured electronics for radios and electron microscopes, along with Wernher von Braun, a teenage engineering student at the Berlin Institute of Technology. An avid amateur astronomer fascinated with the stars and the idea of visiting other planets, von Braun had also become a fan of Oberth’s after reading the original Die Rakete in 1923. The young student saw in Oberth’s work a means to leave the planet, and was in the rare position of having the means to engage in this costly pastime, afforded him by his wealthy father, Magnus Freiherr von Braun.
Valier had given his life to the pursuit of liquid propulsion when Oberth’s new team began experiments that were strikingly similar to the one that claimed their former colleague. At the core of the rocket they were trying to build was a basic engine Oberth called the Kegeldüse. Its combustion chamber was a hollow steel cone with two inlet ports, one for the fuel and the other for the oxidizer. To test the engine, the team secured the chamber inside a metal bucket filled with water as a coolant, oriented so its exhaust end was facing up and any thrust produced pushed downward. The bucket was then placed on a grocer’s scale, allowing Oberth, like Valier before him, to measure the thrust of the engine.
Oberth’s first test came on July 23, 1930. Rain cast a gloomy mood over the group, exacerbated by the presence of an outsider. The director of the sponsoring Reich Institute for Chemistry and Technology was on hand to verify the results and confirm that the money invested hadn’t been wasted. Oberth anxiously watched as his assistants set up the test, then pressurized the combustion chamber. It fell to Riedel, as one of the junior members on the small team, to throw the burning, gasoline-soaked rag into the upward-facing exhaust nozzle. He did, and there was no explosion. Instead, a roaring three-foot-tall spear of flame shot upward from the chamber. The Kegeldüse burned for ninety seconds and delivered a constant thrust of 15.4 pounds. The success of the test vindicated Oberth after the Frau im Mond failure, but without additional research funding he was again forced to return to Romania where a job teaching math to high school students would allow him to support his family. The rocket research stayed in Germany in the hands of Nebel, von Braun, and the rest of the VfR.
The VfR, however, did not have the means to continue where Oberth’s testing left off. They were without university, military, or industry sponsorship and also without a dedicated laboratory space. In addition, they faced legal restrictions over rocket testing, a frustrating if understandable result of Valier’s death. Nebel and Riedel managed some small experiments at a family farm in the latter’s hometown, but it was clear they needed a better space to work, some permanent facility to serve as their home base. If the VfR was going to crack the secrets of liquid-fueled rocket propulsion, they would need a better test site to work the kinks out of their designs than a field in Riedel’s native Bernstadt.
It was Nebel who found the group a home in the fall of 1930. Down a bad road in Berlin’s northern suburb of Reinickendorf, he found a vacant property surrounded by a wire fence. Covering roughly two square miles, the site consisted of a half dozen munitions storage buildings, each surrounded by earthen walls forty feet high and sixty feet thick with narrow passages giving access to the buildings. It was a former ammunitions dump disused since the First World War and a perfect site for rocket testing. Nebel negotiated a lease with the city, which granted the VfR access to the munitions storage sites as well as a small administrative building on the condition that no facility be permanently altered and no equipment installed that could not be removed within forty-eight hours. The cost of the lease more than made up for the restrictive terms. The VfR leased the site for one year for just ten German marks ($42 or £204). On September 27, 1930, the day the group took possession, Nebel mounted a sign on the front that read RAKETENFLUGPLATZ BERLIN. It was Berlin’s first rocket airdrome.
The Raketenflugplatz slowly took shape. The first members of the VfR to arrive set up Spartan living quarters and laboratories before turning their attention to the task of developing a viable liquid-fueled rocket. Without a sponsor, the group relied on members with financial means donating what they could toward building test stands and parts for rocket engines, but more often the group turned to bartering. They would trade unneeded materials for things they did need and offer their skills as mechanics for parts. At times they even bartered for food to keep the team going.
Taking a leaf out of Valier’s book, the VfR also sought to engage the locals and secure donations through public demonstrations. Nebel took the lead in publicizing the VfR’s activities, inviting visitors to the Raketenflugplatz for engine tests. Unfortunately, funding and donations typically hinged on a successful demonstration, and with success fairly rare, the VfR was forced to proceed with minimal resources and simplistic test setups. But when success came it was exciting. The team was testing a Repulsor rocket in early 1931, a design consisting of an engine encased in water for cooling with a long support stick training behind it for guidance. The stick was connected to the liquid oxygen and gasoline tanks that fed the engine. Four fins attached to the base were designed to keep it from flying erratically. A parachute in a compartment at the rocket’s rear end would deploy to slow its landing after the powered flight was over. All told, it was a small rocket, about twelve feet long and weighing about forty-five pounds when fueled. On February 21, the team was testing the Repulsor’s engine when the whole rocket suddenly shot into the air. It rose to about sixty feet before falling back down, sustaining minor damage in the process. It was an accidental first launch, but one the VfR was very pleased with.
The first year at the Raketenflugplatz was a busy one, with 87 launches and 270 static firings, engine tests with the hardware bolted firmly in place so it wouldn’t move. And things seemed poised to improve. The public was still interested in rockets in 1931, so much so that the media was seeking out interesting rocket tests for the sake of a good story. In October, Universum Film-Aktien Gesellschaft, the film company behind Lang’s Frau im Mond, sent a crew to the VfR’s suburban facility to film a weekly newsreel featuring a Repulsor launch. With the cameras rolling, a rocket roared to life and cleared the launchpad, disappearing into the sky before the delighted film crew’s eyes. Soon after, the parachute tore off, and the rocket, still sputtering flames from the remnants of the gasoline in its fuel tank, weaved through the sky before landing on an old shack across the road from the Raketenflugplatz. The last traces of gasoline in the tank set fire to the structure, which turned out to belong to the local police. Uniformed officers stormed the Raketenflugplatz, demanding all rocket testing be stopped immediately. The VfR fought back, arguing that the odd test was bound to go wrong. After much discussion, tempers cooled, and the men settled on a compromise: The VfR could continue firing their rockets provided they place firmer safety restrictions on their activities. It was a happy resolution for the VfR and an entertaining newsreel for UFA. But the media wasn’t the only group with money that was starting to take notice of the rockets flying about the Raketenflugplatz.
CHAPTER TWO
The Rocket Loophole
On a spring day in 1932, three men arrived at the Raketenflugplatz. Though dressed in ordinary street clothes, their demeanors hinted that they weren’t simply interested passersby. The leader of the small group was Colonel Kar
l Becker, the German Army’s chief of Ballistics and Ammunition. Accompanying him was his ammunitions expert, Major Ritter von Horstig. The third man was Captain Walter Dornberger, a lifelong military man whose sole break from the service had come in 1925 when he left briefly to study engineering at the Berlin-Charlottenburg Technische Universität. He resumed service with the army in 1930 with both a bachelor’s and a master’s degree in hand, credentials that facilitated his transfer to the ballistics branch, where he began studying the potential of rockets as offensive weapons. On the day he arrived at the Raketenflugplatz, Dornberger was chief of the army’s powder rockets development program.
The German Army’s interest in rockets as weapons was fairly unique. The offensive use of rockets had fallen out of favor decades earlier with the advent of better artillery and combat aircraft, new technologies that quickly replaced hand-packed cannons that could not be precisely aimed. Aviation also matured rapidly during the First World War. The first airplanes were used as reconnaissance aides, flying in front of cavalry and ground troops for a bird’s-eye view of enemy armies lying in wait. The rear-seated navigators in these reconnaissance planes began carrying guns to fire on enemy armies but soon found themselves firing against their cohorts in the air. To simplify the increasingly common aerial gunfights, armies on both sides of the conflict mounted guns to the front of their airplanes, allowing pilots to direct their fire by flying toward their targets. It was the Fokker aircraft company that made the most significant advance to aerial warfare. Fokker perfected an interrupter gear that ensured automatic weapons always fired between the spinning propeller blades, decreasing the chances of a bullet hitting the spinning blades and ricocheting off in an unwanted direction. Combining the interrupter gear with the German innovation of all-metal fuselages made the nation’s air force one to be reckoned with and helped usher in the era of aerial dogfighting.