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Zdobywanie kosmosu
Temat: Nauka i technologia
Do some Exercises: Słuchaj i zapisuj Tworzenie zdań Ukryte słowa
The National Aeronautics and Space Administration's (NASA) automated spacecraft for solar system exploration come in many shapes and sizes. Each spacecraft consists of various scientific instruments selected for a particular mission, supported by basic subsystems for electrical power, trajectory and orientation control, as well as for processing data and communicating with Earth. NASA uses both electrical power and solar energy. Rechargeable bat¬teries are employed for backup and supplemental power. A subsystem of small thrusters is used to control spacecraft. The thrusters are linked with de¬vices that maintain a constant gaze at selected stars. Just as Earth's early sea¬farers used the stars to navigate the oceans, spacecraft use stars to maintain their bearings in space. Between 1959 and 1971, NASA spacecraft were dis¬patched to study the Moon and the solar environment; they also scanned the inner planets other than Earth - Mercury, Venus and Mars. For the early planetary reconnaissance missions, NASA employed a highly successful se¬ries of spacecraft called the Mariners. Between 1962 and 1975, seven Mariner missions conducted the first surveys of our planetary neighbours in space. In 1972 NASA launched Pioneer 10, a Jupiter spacecraft. Interest was shifting to four of the outer planets - Jupiter, Saturn, Uranus and Neptune. Four NASA spacecraft in all - two Pioneers and two Voyagers - were sent in the 1970s to tour the outer regions of our solar system. Because of the dis¬tances involved, these travellers took anywhere from 20 months to 12 years to reach their destinations. NASA also developed highly specialised spacecraft to revisit our neighbours Mars and Venus in the middle and late 1970s. Twin Vi¬king Landers were equipped to serve as seismic and weather stations and as biology laboratories. Two drum-shaped Pioneer spacecraft visited Venus in 306 1978. A new generation of automated spacecraft - including Magellan, Gali¬leo, Ulysses, Mars Observer and Cassini - is being developed and sent out into the solar system to make detailed examinations that will increase our un¬derstanding of our neighbourhood and our own planett.
