Man-made satellites orbit Earth and other planets or moons. The idea of artificial satellites was first conceived by Isaac Newton through his thought experiment of firing a cannonball fast enough to achieve orbit. The first artificial satellite, Sputnik 1, was launched by the Soviet Union in 1957. There are two main types of satellites: geostationary satellites that orbit above the equator at 35,800 km and have a 24 hour period, and polar satellites that have a lower altitude of 500-800 km and orbit over the north and south poles with a period of 100 minutes. Satellites are used for scientific research, earth observation, communications, navigation, and military purposes.

2. INTRODUCTION
HISTORY
TYPES OF SATELLITES
USES

3. A satellite is an object that orbits
another object.
In satellites may be made by man, or
they may be natural.
The moon is a natural satellite that
orbits the Earth.
Most man-made satellites also orbit
the Earth, but some orbit other planets,
such as Saturn, Venus or Mars, or the
moon.

4.  The idea of a man-made satellite has been
around for a long time.
 When Isaac Newton was thinking about
gravity, he came up with the thought
experiment called Newton's cannonball.
 He wondered what would happen if a
cannonball was shot from a tall mountain
If fired at just the right speed (and ignoring
the friction of air), he realized it would
orbit the Earth
 Later, Jules Verne wrote about a
satellite in 1879 in a book called
Begum's Fortune AND the first satellite
was sputnik 1 on October 4,1957.

5. SATELITES
GEOSTATIONARY POLAR
Height above the
earth-35800km
Time period-24hours
Place-along
equator west to east
Height above the
earth-500 to 800km
Time period-100minutes
Place-along latitude
from north pole to
south pole

6. Man-made satellites have several main uses:
Scientific Investigation
Earth Observation - including weather forecasting
and tracking storms and pollution
Communications - including satellite TV and telephone
calls
Navigation - including Global Positioning System (GPS)
Military - including spy photography and
communications (nuclear weapons are not allowed in
space)