NEXT PAGE
PREVIOUS PAGE
ARTIFICIAL SATELLITES
Any object that ORBITS a planet is called a SATELLITE. The MOON is the only NATURAL satellite of the Earth. Since 1957, THOUSANDS of MAN-MADE objects have been put into orbit. These are often called ARTIFICIAL satellites.
The SOVIET UNION was the FIRST country to:-
a. - put an artificial satellite into orbit when they
launched SPUTNIK 1 on the 4th of October 1957.
b - launch a MANNED satellite when YURI GAGARIN completed
ONE orbit of the Earth on the 12th of April 1961.
c - put a WOMAN into space when, on the 10th of June
1964 VALENTINA TERESHKOVA went into orbit around the Earth.
d - carry out a SPACEWALK when ALEXEI LEONOV achieved
this in March 1965.
e - put a SPACE STATION into orbit around the Earth.
The first one was launched in 1971 (called SALYUT 1), whilst the
LATEST was launched in 1990 (called MIR which means PEACE).
In the first few years of space exploration AMERICA lagged behind the Soviet Union but gradually caught up with and then overtook them. America then went on to concentrate on exploring further afield. On the 20th of July 1969, NEIL ARMSTRONG became the first person to WALK on the MOON. As the cost of space exploration increased, the Americans returned to developing new TECHNOLOGY to orbit the Earth. In April 1981, the first RE-USABLE spacecraft (the SPACE SHUTTLE) flew.
Most of the thousands of ARTIFICIAL satellites which have been launched have been for the following uses:-
a - TELECOMMUNICATIONS. Television programmes and
telephone conversations can be transmitted from country to country by
being BOUNCED off satellites. Modem satellites
receive the signals
and they re transmit them to their destinations.
b - WEATHER FORECASTING. Rain clouds, hurricanes,
etc. can all be
TRACKED using the pictures these satellites
send back to Earth.
c - NAVIGATION. A series of 18 satellites around
the Earth are used by
special receivers on ships and planes to tell
them EXACTLY where they are
to the nearest 10m.
d - MAPPING. Very ACCURATE maps of the whole world,
including the
most REMOTE areas, have been drawn using photographs
sent back by
satellites.
e - MILITARY. Countries can use "SPY"
satellites to find out if another
country is carrying out secret military manoeuvres,
etc.
f - ASTRONOMY. To look at Stars astronomers need to build their
TELESCOPES in places that where there is no AIR or LIGHT
pollution to distort their pictures. It is becoming very
difficult to find such places on Earth. So telescopes are
put into orbit around the Earth, e.g. the HUBBLE SPACE
TELESCOPE.
Satellites which orbit 22,238 miles (35,788 km) above the Earth's EQUATOR are said to be in GEOSTATIONARY orbit. To someone on Earth they appear to be always in the SAME position in the sky. They can "SEE" about 1/3rd of the Earth at any time. Most telecommunications and weather forecasting satellites are in this type of orbit. Other satellites are in POLAR orbit only a few hundreds of miles above the Earth. These are said to be in LOW EARTH ORBIT. These are mainly military satellites which, because of their low orbit, can "SEE" things in great detail.
READ THE PASSAGE ABOVE AND THEN ANSWER THE QUESTIONS BELOW:
1. State the name nationality and date of each of the following "space firsts"
a. Women in space
b. Person to walk on the moon
c. Space station
d. Person to "walk" in space
e. Reusable space craft
2. What is the difference between an artificial and a natural satellite of the earth?
3. Briefly describe six benefits of artificial satellites
4. Briefly describe what each of the following words, used in the passage, mean:-
a. Geostationary
b. Low Earth orbit
c. Polar orbit
5. Complete the crossword on the next page. All the answers to the clues can be found in the passage above.
6. What are the features of a geostationary satellite?
7. If a satellite was placed at the right distance from the Earth to be geostationary in a circular orbit but placed above Britain rather than the equator, how would it appear to move from Britain?
Back to Earth In Space Contents page