Rockets

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/>.