ROCKETS

ROCKETS. In their most basic form, rockets are uncomplicated machines. They comprise a fuel supply, a combustion chamber in which the fuel is burnt, and a nozzle through which the products of combustion—mostly hot gasses—can escape. Early rockets were little more than tubes closed at one end and filled with gunpowder. They were used for fireworks and for maritime rescue (as signals and carriers of lifelines), but they lacked the power and accuracy to be useful beyond these highly specialized niches. Military interest in gunpowder rockets was sporadic and limited. The British use of them to bombard Fort McHenry, near Baltimore during the War of 1812, for example, did more for American culture (by inspiring Francis Scott Key to write "The Star Spangled Banner") than it did for British military objectives.

Modern rockets emerged between 1920 and 1960 from the confluence of several technological breakthroughs:

more powerful fuels, lighter structural elements, steering mechanisms, onboard guidance systems, and multiple stages. These changes set the stage for the rocket's development, from the late 1950s on, into a range of powerful weapons and a versatile tool for scientific exploration.

The Birth of Modern Rocketry, 1920–1960

Robert H. Goddard was the spiritual father but not the true founder of American rocketry. He tested his first solid-fuel rocket on 7 November 1918 and the world's first liquid-fueled rocket (burning gasoline and liquid oxygen) on 16 March 1926. Trained as a physicist, Goddard produced rockets notable more for innovative design features than for sound engineering. He also feared that rivals might steal his ideas—an obsession that led him to publish few papers and keep potential collaborators at arm's length. His genius was prodigious, but his influence was slight.

The foundations of American rocketry were laid, in a practical sense, by four small groups of scientists and engineers scattered across the country. The first of these groups, the American Rocket Society, was formed as the American Interplanetary Society in 1930 by a group of technically minded New York City science fiction writers (they renamed their group in 1934). Its leading members went on to found Reaction Motors, one of America's first rocket-building companies. A second important group coalesced in the late 1930s around aerodynamics expert Theodore von Karman at the California Institute of Technology(Cal Tech). In time this group gave rise to another early rocket-building firm: Aerojet. A third group, led by naval officer Robert Truax, formed in the late 1930s at the Naval Research Laboratory in Annapolis, Maryland. The fourth group consisted of 115 scientists and engineers from Germany's wartime rocket program, led by the charismatic Wernher von Braun and hired by the U.S. Army to apply their expertise to its nascent rocket-building program. They brought with them boxes of technical documents and scores of V-2 rockets—then the world's most advanced—in various stages of assembly. Reassembling and test-firing the V-2s under the Germans' direction gave army rocket experts their first practical experience with large ballistic missiles.

All four groups worked closely with the military. Von Braun's and Truax's were directly supported by the army and navy, respectively. Von Karman worked closely with General Henry H. "Hap" Arnold, commander of the U. S. Army Air Forces. Reaction Motors supplied the engines for most of the Air Force's experimental rocket planes, including the Bell X-1 that broke the "sound barrier" in 1947. Through their military projects, the rocket designers also made connections with established defense contractors. The foundations of a robust aerospace industry had thus been laid even before the end of World War II.

The rockets that emerged from these collaborations in the late 1940s and early 1950s established the basic design elements used by American rockets for the rest of the century. These included multiple stages (1947), lightweight aluminum rocket bodies that doubled as fuel tanks (1948), and swiveling engines for steering (1949). High-energy kerosene derivatives replaced gasoline and alcohol in liquid-fuel rockets. Research at Cal Tech produced a viscous solid fuel that produced more power and higher reliability than traditional powders. Thiokol Chemical Corporation improved it and by the 1950s had enabled solid-fuel rockets to match the power of liquid-fuel ones. Combined, these features created a new generation of rockets. The first representatives—such as the Vanguard and Jupiter of the late 1950s—carried the first small American satellites into space. Later examples—such as Atlas and Titan of the early 1960s—had the power to carry a nuclear warhead halfway around the world or put a manned spacecraft into orbit.

Refinements and Applications, 1960–2000

President John F. Kennedy's May 1961 call to land a man on the moon "before this decade is out" gave von Braun and his team—then working for the National Aeronautics and Space Administration (NASA)—a chance to develop the largest rockets in history. The result was the Saturn V, which made possible nine lunar missions (six of them landings) between December 1968 and December 1972. Taller than the Statue of Liberty and heavier than a navy destroyer, the Saturn V generated the equivalent of 180 million horsepower at the moment of liftoff. However, the Saturn series was a technological dead end. No branch of the military had a practical use for so large a rocket, and (without the spur of a presidential challenge) the civilian space program could not afford to use them for routine exploration. Experiments with nuclear-powered rockets, pursued in the mid-1960s, were discontinued for similar reasons.

Saturn was, therefore, a typical of American rocket development after 1960. Specialization, rather than a continual push for more power and heavier payloads, was the dominant trend. The navy, for example, developed the Polaris—a solid-fuel missile capable of being carried safely aboard submarines and launched underwater. The air force developed the Minuteman as a supplement to the Atlas and Titan. It was smaller, but (because it used solid fuel) easier to maintain and robust enough to be fired directly from underground "silos." All three armed services also developed compact solid-fuel missiles light enough to be carried by vehicles or even individual soldiers. Heat-seeking and radar-guided missiles had, by the Vietnam War (1964–1975), replaced guns as the principal weapon for air-to-air combat. They also emerged, in the course of that war, as the antiaircraft weapons most feared by combat pilots. Warships, after nearly four centuries serving principally as gun platforms, were redesigned as missile platforms in the 1960s and 1970s. "Wire-guided" missiles, first used in combat in October 1966, gave infantry units and army helicopter crews a combination of mobility, accuracy, and striking power once available only to tanks.

The space shuttle, NASA's followup to the Project Apollo moon landings, defined another line of rocket development. Conceived as a vehicle for cheap, reliable access to space, it was powered by three liquid-fuel engines aboard the winged orbiter and two large solid-fuel boosters jettisoned after launch. Both were designed to be reusable. The orbiter's engines would, according to the design specifications, be usable up to fifty times with only limited refurbishing between flights. The boosters, parachuted into the Atlantic Ocean after launch, would be cleaned, refurbished, and refilled with solid fuel for later reuse. By the early 2000s the shuttle, since becoming operational in 1981, had achieved neither the high flight rates nor the low costs its designers envisioned. Its reusability was, nonetheless, a significant achievement in a field where, for centuries, all rockets had been designed as disposable, single-use machines.

BIBLIOGRAPHY

Bromberg, Joan Lisa. NASA and the Space Industry. Baltimore: Johns Hopkins University Press, 1999. Surveys NASA's evolving partnership with aerospace companies.

Heppenheimer, T. A. Countdown: A History of Space Flight. New York: John Wiley, 1997. Places rocket development in its social, political, and military context.

Ley, Willy. Rockets, Missiles, and Men into Space. New York: Viking, 1968. Dated, but useful for its lucid explanations and insider's view of early rocketry.

MacDougall, Walter A. The Heavens and the Earth. New York: Basic Books, 1985. Definitive history of the interplay of Cold War politics, military missiles, and the U. S. space program.

Winter, Frank. Rockets into Space. Cambridge, Mass.: Harvard University Press, 1990. A compact, nontechnical history of rocket technology.

A. BowdoinVan Riper

See alsoMissiles, Military ; National Aeronautics and Space Administration ; Space Program ; Space Shuttle .

Rocketry

The Chinese, in the second century b.c.e., were the first to make simple rockets that used gunpowder for fuel. These simple rockets were fireworks that were used for religious ceremonies. The idea of fireworks soon took on a military usage. Rocket motors were attached to arrows, to greatly extend their range. The same principles that made the rocket arrows fly has allowed people to go to the moon, launch satellites, fly the space shuttle, and even launch rockets that have bowling balls as nose cones. Rocket launches can be seen at Tripoli Rocketry Association and National Association of Rocketry launches throughout the United States. One can see small rockets as well as rockets taller than 14 feet (4.3 meters) being launched.

Rockets fly because of Newton's Third Law of Motion: for every action there is an equal and opposite reaction. Hot gases are produced from the burning of fuel in the rocket motor. The gases push against the inside of the rocket motor as they expand. The hot gas is forced out of the rocket, creating an action force. This creates a reaction force that moves the rocket in the opposite direction. The same thing happens when the end of an inflated balloon is released: the gas escapes in one direction, and the balloon moves in the opposite one.

Until the twentieth century, rockets were small. They were used for firework displays, weapons, to send life lines to ships at sea, and to send signals. Scientists such as Robert Goddard, Konstantin Eduardovich Tsiolkovsky, Hermann Oberth, and Wernher von Braun developed the science and technology that allowed large rockets to fly. In doing so, they developed the science that allowed human space travel.

Goddard realized the potential of rockets and space flight. His analysis of liquid-fuel rocket motors and rocket motors with adjustable thrust, as well as his analysis that rockets could work in space, allowed for the development of today's large rockets. Goddard holds close to seventy patents in rocketry.

In 1903 Konstantin Eduardovich Tsiolkovsky proposed using liquid propellants in rockets, and in 1929 he proposed using multistage rockets as a means of space travel. Hermann Oberth showed that liquid fuels provide a better source of energy for space flight than solid fuels. He worked with young German engineer von Braun to test liquid-fuel motors. Motors were tested in the early 1930s by tossing lit gasoline-soaked rags under a rocket motor, running for cover, and then opening the valve.

Von Braun started to develop rockets for the German army in 1932. He worked in the secret rocket laboratory in Peenemünde, in northeast Germany. He developed the V2 rocket, which served as a guide to start the space programs in the United States and the Soviet Union. This rocket was about 46 feet (14 meters) long and could carry a 2,200-pound (998-kilogram) payload of explosives at speeds of up to 3,500 miles (5,633 kilometers) per hour. Germany first launched the V2 rocket as a weapon of war at Paris on September 6, 1944, and rocket attacks on Britain followed. At the war's end, in 1945, the United States shipped home 100 V2 rockets along with many of the best rocket scientists from Peenemünde. Most of these rockets were launched for scientific research in White Sands, New Mexico. Von Braun spent fifteen years developing missiles for the United States military. He was transferred to NASA in 1960 with a mandate to develop the Saturn rocket, the rocket that went to the moon with the Apollo program.

The world of rocketry changed dramatically on October 4, 1957. The Soviet Union launched Sputnik to an orbit 340 miles (547 kilometers) high.

The satellite circled Earth, sending back a beeping sound that amazed the world. In 1958 the United States successfully launched the 31-pound (14-kilogram) Explorer satellite into space for the first time.

In 1961 humans first reached outer space, when Soviet cosmonaut Yury Gagarin flew for 60 minutes in Vostok 1. On May 5, 1961, Alan Shepard Jr. became the first U.S. astronaut to fly in space. Shepard's Project Mercury flight lasted 15 minutes. John Glenn became the first American astronaut to circle Earth, on February 20, 1962.

Project Gemini launched a capsule for two astronauts. Gemini's ten flights provided experiences with space walks, docking, weightless conditions, and spacecraft recovery that made the Apollo missions to the moon possible.

On July 20, 1969, Neil Armstrong and Buzz Aldrin landed on the moon, where they collected soil and rock samples, took pictures, and performed experiments.

In 1973 astronauts first spent long missions in space on Skylab. This space station enabled experimentation and long stays in space. In 1981 Columbia, the first reusable spacecraft, was launched.

Fuels used in the solid-fuel rockets are a mixture of aluminum metal and ammonium perchlorate. This fuel is used to power the space shuttle boosters. It also powers amateur rockets flown at Tripoli Rocketry Association and National Association of Rocketry launches.

Engines on the space shuttle also burn a mixture of hydrogen and oxygen. The hydrogen and oxygen are compressed and cooled to a liquid in the main fuel tank. When they burn to form water, the combustion is so complete that it often does not look like the motor is burning. Liquid-fuel motors may also burn combinations of kerosene and liquid oxygen. Hybrid motors, using a liquid and solid fuel, are used in amateur rocketry. The fuel

is solid cellulose, and the liquid oxidizer is nitrous oxide (N₂O). The hybrid motors are advantageous, as they have a lower cost per flight than does a solid fuel motor.

NASA's Lewis Research Center is applying new battery technology with space flights. Lithium-ion batteries are flat batteries that are connected in series to obtain the required voltage . They are more efficient and weigh much less than the rechargeable NiCd batteries. They do not use lithium metal and do not require liquid; instead, they use a solid polymer electrode. Even when subjected to high pressure or shorts, the batteries do not explode. Possible spin-off uses include powering cell phones, laptop computers, and electric vehicles.

see also New Battery Technology.

Bill Bertoldi

Bibliography

Alway, Peter (1996). Retro Rockets: Experimental Rockets 1926–1941. Ann Arbor, MI: Saturn Press.

Alway, Peter (1999). Rockets of the World, 3rd edition. Ann Arbor, MI: Saturn Press.

Alway, Peter (2000). In the Shadow of the V-2: 15 Historical Rockets Derived from or Resembling the V-2. Ann Arbor, MI: Saturn Press.

Canepa, Mark (2002). Modern High-Power Rocketry: An Illustrated How-To Guide. Victoria, BC: Trafford.

Chaikin, Andrew (2002). Space: A History of Space Exploration in Photographs. London: Carlton Books.

Engelmann, Joachim (1990). V2: Dawn of the Rocket Age. West Chester, PA: Schiffer.

Furniss, Tim (2001). The History of Space Vehicles. San Diego, CA: Thunder Bay Press.

Launius, Roger D., and Ulrich, Bertram (1998). NASA & the Exploration of Space: With Works from the NASA Art Collection. New York: Stewart, Tabori & Chang.

Stine, G. Harry (1994). Handbook of Model Rocketry, 6th edition. New York: Wiley.

Internet Resources

National Association of Rocketry. Available from <http://www.nar.org>.

Tripoli Rocketry Association. Available from <http://www.tripoli.org>.

Rockets

Rockets are machines propelled by one or more engines especially designed to travel through space. Rocket propulsion results from ejecting fuel backward with as much momentum as possible. One example is a firecracker that misfires and fizzles across the sidewalk. Currently, most rockets use a solid or liquid propellant that relies on a chemical reaction between fuel and oxidizer for thrust. Although chemical rockets can develop great thrust, they are not capable of lengthy operation. To overcome this drawback, research has been conducted on rockets that use different types of chemicals, or reactants. One type of nonchemical rocket is powered by ion propulsion . These rockets turn fuel into plasma and eject the ions to create thrust. Nuclear rockets that use a nuclear reactor to heat and eject fuel are still at the experimental stage. Scientists have also outlined schemes for fusion pulse rockets, solar sail rockets, and photon rockets.

From "Fire Arrows" to Modern Rocketry

The Chinese were probably the first to use rockets. In 1232 C.E. they defeated a Mongol invasion using a strange weapon called "fire arrows." Filled with an explosive combination of saltpeter and black powder, these were the primitive ancestors of rockets. Later, this new weapon was carried as far as the Near East and Europe. By the sixteenth century, Europeans had taken the lead in exploiting the potential of rockets in warfare.

Rapid progress in military rocketry was made in the nineteenth century. Over 25,000 rockets developed by British artillery officer William Congrieve were launched against Copenhagen, Denmark, in 1807. The same type of rocket was immortalized as "the rocket's red glare" in "The Star-Spangled Banner." Beyond their martial applications, recognition of the potential of rockets in spaceflight began to emerge in the late nineteenth and early twentieth centuries through individuals who were to have a profound impact on the coming space age.

In Russia, the writings of Konstantin Tsiolkovsky greatly influenced many rocket pioneers. Robert H. Goddard, the father of rocketry in America, discovered, as Tsiolkovsky had, that the combination of liquid oxygen and liquid hydrogen would make an ideal rocket propellant. In March 1926, a 4-meter-tall (13-foot-tall) projectile, the world's first liquid-propellant rocket, was launched from the Goddard family farm in Massachusetts. Later, Goddard set up a facility in New Mexico, where, in 1935, he launched a sophisticated rocket stabilized by gyroscopes and cooled by frigid propel-lant—features common to all modern chemical rockets.

As Goddard labored in the desert, rocket trailblazer Hermann Oberth proposed to the German Army the development of liquid-fueled, long-range rockets. During World War II (1939-1945), Oberth worked together with Wernher von Braun to develop the V-2 rocket for the Germans. On October 3, 1942, a V-2 was launched from Peenemunde on the Baltic coast and reached the edge of space—an altitude of 85 kilometers (53 miles)—becoming the first rocket to do so. After the war, captured V-2s were brought to the United States and Soviet Union and became the basis for postwar rocket research in both countries. The first major development in postwar rocket technology was the concept of multiple stages in which the rocket's first stage reaches its peak altitude and the second stage is "launched" from the first stage closer to space. This concept is used today on all major launch vehicles, with three-and four-stage rockets not uncommon.

The Origin of Today's Rockets

In the 1950s, von Braun and his "Rocket Team," many of whom had immigrated to the United States, continued their work on multistage rockets near Huntsville, Alabama. There they developed the Jupiter rocket, which evolved into the Redstone launch vehicle, which sent the first two U.S. astronauts into space. Meanwhile, in the Soviet Union, a team headed by Sergei Korolev developed the R-7 ("Semyorka") rocket, which launched the first artificial satellite, Sputnik 1, in October 1957, and the first man and woman into orbit.

Throughout the late 1950s and early 1960s, the United States developed a series of intercontinental ballistic missiles—Atlas, Thor, and Titan—that would play key roles in both piloted and unpiloted space missions. The Atlas was used to launch Mercury astronauts and satellites into orbit. The Thor gradually evolved into the highly versatile Delta series of rockets, which have launched a large number of National Aeronautics and Space Administration (NASA) planetary missions since the late 1960s. In its various subtypes, the Titan continues to serve both NASA and the U.S. Air Force as a heavy launcher for planetary probes and reconnaissance satellites.

While these vehicles are descendents of military rockets, the Saturn series of launch vehicles, the most powerful ever built by the United States, was developed expressly for the Apollo Moon program. The smaller Saturn 1B was used for the first crewed Apollo mission in 1968 and later lifted all three crews to the Skylab space station. The Saturn V, standing 117 meters (384 feet) tall, powered all Apollo missions to the Moon from 1968 to 1972. The Soviets also developed a series of advanced rockets, such as the Soyuz and Proton, but their "Moon rocket," the N-1, never successfully flew.

The space shuttle marked a radical departure from previous "expendable" rockets. The winged shuttle orbiter, flanked by two solid-propellant boosters, was designed to be reused dozens of times. While many rockets, such as the shuttle, are owned and operated by government, the commercial launch industry had grown enormously since the 1970s and become more international. Today, the International Launch Services company provides launch services on the American Atlas II, III, and V and the Russian Proton vehicles to customers worldwide. Meanwhile, the Boeing Company launches the Delta II, III, and IV and is a partner in Sea Launch, which launches Zenit rockets. Arianespace, a European consortium, is also a major player in the commercial launch industry, producing Ariane 4 and 5 rockets.

The history of rocketry is a long one, and rockets will continue to play important roles in commerce, science, and defense.

see also External Tank (volume 3); Goddard, Robert Hutchings (volume 1); Korolev, Sergei (volume 3); Launch Management (volume 3); Launch Sites (volume 3); Oberth, Hermann (volume 1); Tsiolkovsky, Konstantin (volume 3); von Braun, Wernher (volume 3).

John F. Kross

Bibliography

Aldrin, Buzz, and John F. Kross. "Reusable Launch Vehicles: A Perspective." Ad Astra 7, no. 2 (1995):30-35.

Hacker, Barton C., and James M. Grimwood. On the Shoulders of Titans: A History of Project Gemini. Washington, DC: National Aeronautics and Space Administration, 1977.

Kross, John F. "These Are Not Your Father's Rocketships Anymore." Ad Astra 7, no.2 (1995):22-29.

Lewis, Richard S. Appointment on the Moon. New York: Viking Press, 1968.

Oberg, James E. The New Race for Space. Harrisburg, PA: Stackpole Books, 1984.

Ordway, Frederick I., and Mitchell R. Sharpe. The Rocket Team. New York: Thomas Y. Cromwell, 1979.

Shelton, William R. Man's Conquest of Space. Washington, DC: National Geographic Society, 1975.

Tilley, Donald E., and Walter Thumm. Physics. Menlo Park, CA: Cummings Publishing Co., 1974.

Yenne, Bill. The Encyclopedia of US Spacecraft. New York: Exeter Books, 1988.

Internet Resources

Arianespace. <http://www.arianespace.com/>.

"Delta Launch Vehicles." Boeing Company. <http://www.boeing.com/defense-space/space/delta/delta4/delta4.htm>.

International Launch Services. <http://www.ilslaunch.com/atlas/historicalflights/>.

rock·et¹ / ˈräkit/ • n. a cylindrical projectile that can be propelled to a great height or distance by the combustion of its contents, used typically as a firework or signal. ∎  (also rock·et en·gine or rock·et mo·tor) an engine operating on the same principle, providing thrust as in a jet engine but without depending on the intake of air for combustion, an oxidizer being carried on board along with the fuel. ∎  an elongated rocket-propelled missile or spacecraft. ∎  used, esp. in similes and comparisons, to refer to a person or thing that moves very fast or to an action that is done with great force: she shot out of her chair like a rocket. • v. (rock·et·ed , rock·et·ing ) 1. [intr.] (of an amount, price, etc.) increase very rapidly and suddenly: sales of milk in supermarkets are rocketing | [as adj.] (rocketing) rocketing prices. ∎  move or progress very rapidly: the cab rocketed down a ramp he rocketed to national stardom. ∎  [tr.] cause to move or progress very rapidly: she showed the kind of form that rocketed her to the semifinals last year. 2. [tr.] attack with rocket-propelled missiles: the city was rocketed and bombed from the air.DERIVATIVES: rock·et·like / -ˌlīk/ adj.rock·et² • n. (also garden rocket or salad rocket) an edible Mediterranean plant (Eruca vesicaria subsp. sativa) of the cabbage family, sometimes eaten in salads. ∎  used in names of other fast-growing plants of this family, e.g., dame's rocket.

rocket Slender, tapering missile or craft powered by a rocket engine. Most of its volume contains fuel; the remainder is the payload (such as an explosive, scientific instruments, or a spacecraft). Liquid-fuelled rockets use a fuel (such as liquid hydrogen) and an oxidizer (usually liquid oxygen), which burn together in the engine. Solid-fuelled rockets have both fuel and oxidizer in a solid mixture. A single-stage rocket has one fuel load, or several that are used simultaneously. A multi-stage rocket has several fuel loads, which are ignited singly in succession as the preceding one burns out. Because rocket engines carry their own fuel and oxidizer, they can operate in outer space where there is no atmosphere. They gain thrust from the reaction (referred to in the third of Newton's laws of motion) produced by rapid, continuous output of exhaust gases. Chemical rocket engines are powered by solid or liquid propellants that are burned in a combustion chamber. The propellants are expelled at supersonic velocity from the exhaust nozzle.