Main->Readings->5th Grade Readings->Human Spaceflight->Part 2
Vocabulary |
In most of the history of the Earth, Earth had only one satellite. A satellite is an object which orbits another body in space, and Earth's only satellite before 1957 was our Moon. But in October 1957, Earth got its first artificial satellite: a basketball-sized globe of metal with four metal rods sticking out of it. Human beings had put it there, and though it was very small and simple, its launching was a great milestone in human history.
This satellite was called Sputnik, a Russian word meaning "traveling companion," and it had been launched by the Soviet Union. It was 23 inches wide and weighed 184 pounds, and it had been carried up to 142 miles above the Earth's surface by a rocket, inside a nose cone. At that height, and at a speed of nearly 5 miles a second, the nose cone came off and the metal ball separated from the rocket, continued to move, and kept going in orbit around the Earth for three months, going around once every 96 minutes.
Sputnik 1
Courtesy of NASA
Astronomy Picture of the Day
October 3, 1998, accessed July 19, 2000
http://antwrp.gsfc.nasa.gov/apod/ap981003.html
This was a thrilling achievement, and people all over the world were very excited. However, Sputnik was also very disturbing to the United States. For one thing, the U.S. was disappointed it had not been the first to place an artificial satellite in orbit. For another, Sputnik could travel through the sky above our heads, and it showed that no country was completely safe from observation or even bombing from space. This made the citizens of the United States even more eager to achieve space-flight.
Like most other space missions since then, Sputnik was also a test mission for future space-flights. Soviet scientists had questions that needed to be answered before they could send up another mission, and Sputnik could answer them. For instance, could an object in orbit around the Earth be kept at a steady temperature to keep humans alive when it came time for manned spaceflight? To answer this and other questions, there were instruments inside Sputnik keeping track of temperature and other things, and the instruments sent radio signals back to Earth.
Soon after Sputnik's launch, another object was sent into orbit, again by the Soviet Union. On November 3, 1957, the Soviets launched Sputnik 2. Sputnik 2 was a 12-foot-long cone weighing 1,000 pounds more than Sputnik 1 and carrying the first living creature to go into space: a female dog whom everybody called Laika ("Barker" in Russian).
Why did the Soviets send a dog into space instead of a human being? They were not ready to risk a human life, and it was considered better to test with animals first when any risk was involved. They needed to know what acceleration, weightlessness, and other conditions of spaceflight would do to a living creature. Laika had been put through a training program which taught her not to be frightened by the noise and vibration of take-off. Her space capsule was comfortable, and she had machinery which automatically fed her while she was in space. Instruments kept track of her heartbeat, breathing, and other body activities and radioed the information back to Earth. The Soviets said that she was calm and unafraid during her seven days in orbit, and for 40 years everyone believed that, but in 2002 Russian scientists admitted she died after only five to seven hours of flight, from overheating and stress.
Laika
Picture courtesy of NASA,
Sputnik: the Fortieth Anniversary
http://www.hq.nasa.gov/office/pao/History/sputnik/laika.jpg
Even if she had survived, the Soviets had not yet figured out a way to bring a spacecraft down safely. They had not yet solved the problem of re-entry. Also, Sputnik would automatically begin to fall out of orbit after seven days, come back into Earth's atmosphere, and burn up from friction.
Laika had proved that a living thing could go into space and survive, and therefore human beings might also be able to go into space.
The United States was very anxious to keep up with the Soviet Union. On January 31, 1958, the U.S. sent up its own artificial satellite, Explorer I, using an Army Juno I rocket to send it up. Explorer I looked like a metal tube; it was only 6 inches wide, 6 1/2 feet long, and weighed about 30 pounds. However, it went farther up than either Sputnik mission had, and its instruments found that above 600 miles there was a "belt" of deadly radiation around the Earth. For a while, people believed we could not send a human into space any farther than Sputnik 2 because the radiation would kill them. However, other satellites, sent up later on, showed it was possible to shield against the radiation.
Explorer I
Picture courtesy of NASA
International Solar-Terrestrial Physics Program
Radiation
Belts, June 5, 1996
accessed July 19, 2000,
http://www-spof.gsfc.nasa.gov/Education/Iradbelt.html
The Sputniks and Explorer I might seem small and simple to us now, but they marked the beginning of the space age. Before we sent these primitive satellites into orbit, the Moon was the only thing going around the Earth. This is why simple spacecraft like the Sputniks and Explorer I hold a special place in history.
Go on to Part 3: Leaving the Planet: The First Human in Space
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This page last modified on February 10, 2003