Page 22 - Curriculum Visions Dynamic Book

The development of vehicles capable of traveling into space was a complex affair that took decades. As the last chapter showed, much was learned during World War II, but the idea of leaving something useful—a payload—in space still had to be realized. There was no need to design a payload that was aerodynamic, because in space there is no air and so no air resistance. That is why the first satellites looked very different from any rocket or aircraft.
The development of these machines was not simply a matter of science and technology. During this period there was also intense political competition between the two superpowers, the United States and the Soviet Union, to be the first to master this new and powerful technology.
It became known as the space race.
The political arena tended to change, or distort, what scientists and technologists might otherwise have done. We will see that in this chapter.
Sputnik
The first object put into space was Sputnik 1. It was launched on October 4, 1957, by the then Soviet Union. It looked rather like a metal ball with skewers sticking out of it.
The launcher carried the satellite to a speed of 7.99 km per second, thus allowing it to escape the Earth’s gravity. As it entered orbit, a nose cone came away, revealing a further nose cone, which was also released. Sputnik, being spring-loaded, was then ejected from its launcher. Four aerials sprang out, each 3 m long, and they provided the communications for the two transmitters.
It was possible to receive the signals all over the world, including in schools. The Morse-codelike (bleep, bleep) signal was heard around the world. It marked the start of the Space Age in the most dramatic fashion. Sputnik weighed
82 kg and at its highest orbital point reached 939 km above the Earth’s surface. Its orbit took 1 hour 36 minutes.
aerodynamic A shape offering as little resistance to the air as possible.
air resistance The frictional drag that an object creates as it moves rapidly through the air.
doppler effect The apparent change in pitch of a fast-moving object as it approaches or leaves an observer.
frequency The number of complete cycles of (for example, radio) waves received per second.
global positioning system A network of geostationary satellites that can be used to locate the position of any object on the Earth’s surface.
gravity The force of attraction between bodies.
ionosphere A part of the Earth’s atmosphere in which the number of ions (electrically charged particles) is enough to affect how radio waves move.
optical Relating to the use of light. orbit The path followed by one object as
it tracks around another.
payload The spacecraft that is carried into space by a launcher.
radio waves A form of electromagnetic radiation, like light and heat. Radio waves have a longer wavelength than light waves.
satellite A man-made object that orbits the Earth.
sensor Adeviceusedtodetectsomething.
space race The period from the 1950s to the 1970s when the United States and the Soviet Union competed to be first in achievements in space.
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