Space Travel | Encyclopedia.com
Space Travel | Encyclopedia.com
In the early-thirteenth century, the Chinese invented the rocket by packing gunpowder into a tube and setting fire to the powder. Half a millenium later, the British Army colonel, William Congreve, developed a rocket that could carry a 20-pound warhead nearly three miles. In 1926, the American physicist Robert Goddard built and flew the first liquid-fueled rocket, becoming the father of rocket science in the United States. In Russia, a mathematics teacher named Konstantin Tsiolkovsky derived and published the mathematical theory and equations governing rocket propulsion.
Tsiolkovsky’s work was largely ignored until the Germans began to employ it to build rocket-based weapons in the 1920s under the leadership of mathematician and physicist Hermann Oberth. In October of 1942, the Germans launched the first rocket to penetrate the lower reaches of space. It reached a speed of 3,500 miles per hour, giving it a range of about 190 miles. The technology and design of the German rocket were essentially the same as those pioneered by Goddard. The successors of this first rocket would be the infamous V-2 ballistic missiles, which the Nazis launched against England in 1944 and 1945. This assault came too late to turn the course of the war in Germany‘s favor, but devastating enough to get the full attention of the U.S. government.
Many of the German V-2 rocket scientists, led by Werhner von Braun, surrendered to the Americans and were brought to the United States, where they became the core of the American rocket science program in the late-1940s, 1950s, and 1960s. Von Braun and his team took the basic technology of the V-2 missiles and scaled it up to build larger and larger rockets fueled by liquid hydrogen and liquid oxygen.
The Weapons Race Leads to a Space Race
In the beginning, the focus of the American rocket program was on national defense. After World War II, the United States and the Soviet Union emerged as the world’s two most formidable powers. Each country was determined to keep its arsenal of weapons at least one step ahead of the other’s. Chief among those arsenals would be intercontinental ballistic missiles, huge rockets that could carry nuclear warheads to the cities and defense installations of the enemy. To reach a target on the other side of the world, these rockets had to make suborbital flights, soaring briefly into space and back down again. In the 1950s, as rocket engines became more and more powerful, both nations realized that it would soon be possible to send objects into orbit around Earth and eventually to the Moon and other planets. Thus, the Cold War missile race gave birth to the space race and the possibility of eventual space flight by humans.
Werhner von Braun and his team of rocket scientists were sent to the Redstone Army Arsenal near Huntsville, Alabama and given the task of designing a super V-2 type rocket, which would be called the Redstone, named for its home base. The first Redstone rocket was launched from Cape Canaveral, Florida on August 20, 1953. Three years later, on September 20, 1956, the Jupiter C Missile RS-27, a modified Redstone, became the first missile to achieve deep space penetration, soaring to an altitude of 680 miles above Earth’s surface and traveling more than 3,300 miles.
Meanwhile, in the Soviet Union, rocket scientists and engineers, led by Sergei Korolyev, were working to develop and build their own intercontinental ballistic missile system. In August of 1957, the Soviets launched the first successful Intercontinental Ballistic Missile (ICBM), called the R-7. However, the shot heard round the world would be fired two months later, on October 4, 1957, when the Soviets launched a modified R-7 rocket carrying the world’s first man-made satellite, called Sputnik. Sputnik was a small, 23-inch aluminum sphere carrying two radio transmitters, but its impact on the world, and especially on the United States, was enormous. The “space race” had begun in earnest—there would be no turning back.
One month later, the Soviets launched Sputnik 2, which carried Earth’s first space traveler, a dog named Laika. The United States government and its people were stunned by the Soviet successes and the first attempt by the United States to launch a satellite was pushed ahead of schedule to December 6, 1957, just a month after Laika’s journey into space. The Vanguard launch rocket, which was supposed to propel the satellite into orbit, exploded shortly after lift-off. It was one of a series of U.S. failures, and dealt a serious blow to Americans’ confidence in the country’s science and engineering programs, which were previously thought to be the best in the world. Success finally occurred on January 31, 1958 with the launch of the first U.S. satellite, Explorer 1, which rode into space atop another Jupiter C rocket.
The Race to the Moon
Both the Soviet Union and the United States wanted to be the first to send a satellite to the Moon. In 1958, both countries attempted several launches targeting the Moon, but none of the spacecraft managed to reach the 25,000 miles per hour speed necessary to break free of Earth’s gravity.
On January 2, 1959, the Soviet spacecraft Luna 1 became the first artificial object to escape Earth’s orbit, although it did not reach the Moon as planned. However, eight months later, on September 14, 1959, Luna 2 became the first man-made object to strike the lunar surface, giving the Soviets yet another first in the space race. A month later, Luna 3 flew around the Moon and radioed back the first pictures of the far side of the Moon, which is not visible from Earth.
The United States did not resume its attempts to send an object to the Moon until 1962, but by then, the space race had taken on a decidedly human face. On April 12, 1961, an R-7 rocket boosted a spacecraft named Vostok that carried 27-year-old Soviet cosmonaut Yuri Gagarin into Earth orbit and into history as the first human in space. Gagarin’s 108-minute flight and safe return to Earth placed the Soviet Union clearly in the lead in the space race. Less than a month later, on May 5, 1961, a Redstone booster rocket sent the U.S. Mercury space capsule, Freedom 7, which carried American astronaut Alan Shepard, on a 15-minute suborbital flight. The United States was in space, but just barely. An American would not orbit Earth until February of 1962, when astronaut John Glenn‘s Mercury capsule, Friendship 7, would be lifted into orbit by the first of a new generation of American rockets known as Atlas.
Just weeks after Shepard’s suborbital flight in 1961, U.S. President John F. Kennedy announced that a major goal for the United States was to send a man to the Moon and return him safely to Earth before the end of the decade. The fulfillment of that goal was to be the result of one of the greatest scientific and engineering efforts in the history of humanity. The project cost a staggering $25 billion, but Congress and the American people had become alarmed by the Soviets’ early lead in the space race and were more than ready to fund Kennedy’s bold vision.
The Mercury and Vostok programs became the first steps in the race to the Moon, showing that humans could survive in space and be safely brought back to Earth, but the Mercury and Vostok spacecraft were not designed to take humans to the Moon. By 1964, the Soviet Union was ready to take the next step with a spacecraft named Voskhod. In October of 1964, Voskhod 1 carried three cosmonauts, the first multi-person space crew, into orbit. They stayed in orbit for a day and then returned safely to Earth. In March of 1965, the Soviets launched Voskhod 2 with another three-man crew. One of the three, Alexei Leonov, became the first human to “walk” in space.
Within weeks of Leonov’s walk, the United States launched the first manned flight of its second-generation Gemini spacecraft. The Gemini was built to carry two humans in considerably more comfort than the tiny Mercury capsule. Although Gemini was not the craft that would ultimately take men to the Moon, it was the craft that would allow American astronauts to practice many of the maneuvers they would need to use on lunar missions. Ten Gemini missions were flown in 1965 and 1966. On these missions, astronauts would walk in space, steer their spacecraft into a different orbit, rendezvous with another Gemini craft, dock with an unmanned spacecraft, reach a record altitude of 850 miles above Earth’s surface, and set a new endurance record of 14 days in space. When the Gemini program came to an end in November of 1966, the United States had taken the lead in the race to the Moon. The Soviets had abandoned their Voskhod program after just two missions to concentrate their efforts on reaching the Moon before the United States. Both countries developed a third-generation spacecraft designed to fly to the Moon and back. The Soviet version was called Soyuz, while the American version was named Apollo. Both could accommodate a three-person crew.
In November of 1967, Werhner von Braun’s giant Saturn V rocket was ready for its first test flight. The three-stage behemoth stood 363 feet high, including the Apollo command module perched on top. Its first stage engines delivered 7.5 million pounds of thrust, making it the most powerful rocket ever to fly. On its first test flight, the mighty Saturn launched an unmanned Apollo spacecraft to an altitude of 11,000 miles above Earth’s surface. On December 21, 1968, the Saturn V boosted astronauts Frank Borman, Jim Lovell, and Bill Anders inside their Apollo 8 spacecraft into Earth orbit. After two hours in orbit, the Saturn’s third stage engines fired one more time, increasing Apollo 8’s velocity to 25,000 miles per hour. For the first time in history, humans had escaped the pull of Earth’s gravity and were on their way to the Moon.
On December 24, Apollo 8 entered lunar orbit, where it would stay for the next twenty hours mapping the lunar surface and sending back television pictures to Earth. Apollo 8 was not a landing mission, so on December 25, the astronauts fired their booster rockets and headed back to Earth, splashing down in the Pacific Ocean two days later. The last year of the decade was about to begin and the stage was set to fulfill President Kennedy’s goal. Two more preparatory missions, Apollo 9 and Apollo 10, would be used to do a full testing of the Apollo command module and the lunar module, which would take the astronauts to the surface of the Moon.
The astronauts chosen to ride Apollo 11 to the Moon were Neil Armstrong, Edwin “Buzz” Aldrin, and Michael Collins. Liftoff occurred on July 16, 1969, with Apollo 11 reaching lunar orbit on July 20. Armstrong and Aldrin squeezed into the small spider-like lunar module named Eagle, closed the hatch, separated from the command module, and began their descent to the lunar surface. Back on Earth, the world watched in anticipation as Neil Armstrong guided his fragile craft toward the gray dust of the Moon’s Sea of Tranquility. Armstrong’s words came back across 239,000 miles of space: “Houston. Tranquility Base here. The Eagle has landed.” At 10:56 p.m., eastern standard time, July 20, 1969, Armstrong became the first human to step on the surface of another world. “That’s one small step for a man,” he proclaimed, “and one giant leap for mankind.” Aldrin followed Armstrong onto the lunar surface, where they planted an American flag and then began collecting soil and rock samples to bring back to Earth. The Apollo 11 astronauts returned safely to Earth on July 24, fulfilling President Kennedy’s goal with five months to spare.
Five more teams of astronauts would walk and carry out experiments on the Moon through 1972. A sixth team, the crew of Apollo 13, was forced to abort their mission when an oxygen tank exploded inside the service module of the spacecraft. On December 14, 1972, after a stunning three-day exploration of the lunar region known as Taurus-Littrow, astronauts Eugene Cernan and Harrison Schmitt fired the ascent rockets of the Lunar module Challenger to rejoin crewmate Ron Evans in the Apollo 17 command module for the journey back to Earth.
Apollo 17 was the final manned mission to the Moon of the twentieth century. The American people and their representatives in Congress had exhausted their patience with paying the huge sums necessary to send humans into space. The Soviets never did send humans to the Moon. After the initial Soyuz flights, their Moon program was plagued by repeated failures in technology, and once the United States had landed men on the Moon, the Soviet government called off any additional efforts to achieve a lunar landing.
Although the Apollo program did not lead to an immediate establishment of scientific bases on the Moon or human missions to Mars as was once envisioned, human spaceflight did not end. The three decades following the final journey of Apollo 17 have seen the development of the space shuttle program in the United States, as well as active space programs in Russia, Europe, and Japan. Scientific work is currently under way aboard the International Space Station, with space shuttle flights ferrying astronauts, scientists, and materials to and from the station. Deep spaceflights by humans to the outer planets and the stars await significant breakthroughs in rocket propulsion.
see also Astronaut; Space, Commercialization of; Space Exploration; Space, Growing Old in; Spaceflight, Mathematics of.
Hale, Francis J. Introduction to Space Flight. Upper Saddle River, NJ: Prentice Hall, 1998.
Heppenheimer, T. A. Countdown: A History of Spaceflight. New York: John Wiley and Sons, 1999.
Watson, Russell and John Barry. “Rockets.” In Newsweek Special Issue: The Power of Invention. Winter (1997–1998): 64–66.
NASA Goddard Space Flight Center Homepage. <http://www.gsfc.nasa.gov/>.
* : ) here → *
Space Travel | Encyclopedia.com