What Effects A Satellite?
Donna M. / Physics 337 / 17 April 1997
There are many different factors that contribute to the way a satellite
functions. Orbital positions, gravitational forces, and disturbances in
the atmosphere are just a few examples of this fact. Scientists must account
for these factors when creating satellites so that they can solve any problems
quickly and accurately. Some problems that might have to be dealt with
are a change in the position of the satellite, or its failure to operate
correctly. However, once scientists are able to understand the causes of
the problems, they can try to solve them so that the satellite will function
The positions of an orbit and the conditions it is under can help determine
the effectiveness of a satellite. "If the orbit is low, the resistance
of the outer atmosphere will cause the satellite to decay-- that is, to
lose orbital speed and re-enter the atmosphere. The higher above the earth
the orbit is, the longer the lifetime of the satellite..." (Ordway
288). If a satellite is too low, any nuclear reactor it may have can become
a potential threat. It is difficult to determine the most beneficial spot
for a satellite's orbit. According to Ordway, if a satellite is too low
it can be disturbed by the flattening of the poles of the earth, but if
it is too high it can be disturbed by the attraction of the sun and the
moon (288). The ellipse of an orbit is also an important factor. If the
ellipse does not move, the satellite is more effective. On the other hand,
if the ellipse does move, the satellite will move with it and become less
Forces Effecting Satellites:
The constant pull of many forces determine the way a satellite will
move and how it should be launched. Gravity is the force of attraction
on an object by the earth. It is the factor that gives an object weight.
The farther away from the earth an object is, the less gravitational attraction
it feels toward the earth. Therefore, the acceleration increases with the
distance. Centripetal and centrifugal forces also effect satellites. The
centripetal, or center-seeking, force is the force which causes an object
to move in a circular path, and is always directed towards the center of
the circle. The centrifugal force acts in a direction away from the center,
and is proportional to the mass. These factors make the centrifugal force
act like a gravitational force.
Disturbances With Satellites:
Disturbances with satellites can be connected with distortions in the
gravitational field, orbiting reactors, and the need for corrections. Corrections
are necessary because of the drifting of satellites. "The Earth's
bulging equator and other distortions in its gravitational field continually
tug at the craft, often causing it to drift away from its planned orbit.
They can also shift a satellite into a position where it can no longer
fulfill its mission" (Cowen). Gamma rays are units of short-wavelength
radiation and are produced by orbiting reactors. According to Beardsley,
these reactors can cause a great deal of damage if they are burned in the
atmosphere (14-15). Some organizations have worked to ban these reactors
in an effort to decrease the danger involved.
As you can see, there are many variables that must be taken into consideration
when observing a satellite. Orbits, forces, and possible radioactive contamination
are all carefully thought about when creating a satellite. These factors
contribute to the way a satellite is launched, where its orbit will be,
and the length of time it will be helpful to scientists. Satellites are
very complicated structures, but their discoveries can be very helpful
Beardsley, Tim. "Stable Orbit" Scientific America.
February 1989, Vol. 260, p. 14-15.
Capara, Giovanni. The Complete Encyclopedia of Space Satellites.
New York: Portland
Cowen, R. "Painting a Color Portrait of Stable Orbits" Science
News. February 24,
1990, Vol. 137, p. 116.
Ordway, Fredrick. "Artificial Satellites" Encyclopedia
Americana. 1993 ed., p. 288.
"Space Travel" The World Book Encyclopedia. Chicago:
Field Enterprises Educational