Physics of Satellites
Philip S. / Physics of Satellites / 15 April 1997
Satellites play a very big part in our lives. Without the use of satellites
we wouldn't be able to watch television, be able to communicate to the
other side of the earth. Satellites aren't just in space they have to be
put there. This part is very important step on using a satellite. What
goes up must come down, so there comes the problem of bringing the satellite
back to earth.
The launching of a satellite varies in two ways. The first way of launching
a satellite is to carry it into space on a space shuttle. "Space shuttles
carry some satellites into space."(Oberright,3) Then when the satellite
is raised to the required height it is given a thrust into orbit. There
is another way of launching a satellite into space, this method of launching
is done with a rocket. A satellite is put into a rocket and launched into
space. "The method of launching is to raise the projectile to the
required height and then iv it a side ways thrust which will throw it into
the right orbit."(Oberright,3) When rocket is launched upward into
space the rockets fuel is spent, the satellite separates from the rocket
and the rocket falls from space and into the ocean. The satellite is left
in space. The satellite requires minor adjustment, this is done by built
in rockets called thrusters. When a satellite is up in orbit it stays in
orbit for a long time.
Retrieving of Satellites
Satellites don't last for ever. When a satellite has out lived its
usefulness or needs to be repaired or replaced it needs to be retrieved.
There are also two different ways of retrieving a satellite. One way of
retrieving a satellite is by it falling from its orbit. "A satellite
remains in orbit until its velocity decreases and the gravitational forces
pulls it down into a relatively dense part of the atmosphere. A satellite
slows down due to friction of air particles in the upper atmosphere and
the gentle pressure of the sun's energy. When the gravitational force pulls
the satellite down far enough into the atmosphere, the satellite rapidly
compresses the air in front of it. This air becomes so hot that most or
all of the satellite burns up."(Oberright,4)
The other way a satellite is retrieved is with a space shuttles This
isn't something that happens often. If this does occur it is because the
satellite needs to be repaired or reprogrammed. When it does happen a space shuttles
crew go up into space and try to repair the satellite. The satellite is
repaired in space or it is taken back to earth for its repairs or reprogramming.
If the satellite isn't repairable reprogrammable the operator at the control
center shuts the satellite off and it falls out of orbit and either drifts
into space or falls to earth.
Without satellites everything would be different, for example television.
Without a satellite to transmit the programs we wouldn't have any television.
There for satellites due play a big role in our lives and without being
able to launch a satellite into space or be able to retrieve it from space
we wouldn't have such things as television.
Olberright, John E. "Satellite, Artificial" World Book Information
CD-ROM:World Book Inc,1993