|
|
|
 
Satellites
Satellites orbit the earth doing our bidding in ways that enrich the lives
of almost all of us. Through electronic eyes from hundreds of miles
overhead, they lead prospectors to mineral deposits invisble on earth's
surface. Relaying communications at the speed of light, they shrink the
planet until its most distant people are only a split second apart. They
beam world weather to our living room TV and guide ships through storms.
Swooping low over areas of possible hostility, spies in the sky maintain a
surveillance that helps keep peace in a volatile world.
How many objects, exaclty, are orbiting out there? Today's count is 4,914.
The satellites begin with a launch, which in the U.S. takes place at Cape
Canaveral in Florida, NASA's Wallops Flight Center in Virginia, or, for
polar orbiters, Vandenberg Air Force Base in California. One satellite in
20 is crippled by the jolt of lift-off, or dies in the inferno of a
defective rocket blast, or is thrust into improper orbit. A few simply
vanish into the immensity of space. When a satellite emerges from the
rocket's protective shroud, radiotelemety regularly reports on its health
to round-the-clock crews of ground controllers. They watch over the
temperatures and voltages of the craft's electronic nervous system and
other vital "organs", always critical with machines whose sunward side may
be 300 degress hotter than the shaded part.
Once a satellite achieves orbit--that delicate condition in which the pull
of earth's gravity is matched by the outward fling of the crafts speed--
subtle pressures make it go astray. Solar flares make the satellite go
out of orbit. Wisps of outer atmosphere drag its speed. Like strands of
spiderweb, gravity feilds of the earth, moon, and sun tug at the orbiting
spacefarer. Even the sunshine's soft caress exerts a gentle nudge. Should
a satellite begin to wander, ground crews fire small fuel jets that steer
it back on course. This is done sparingly, for exhaustion of these gases
ends a craft's useful career. Under such stresses, many satellites last 2
years. When death is only a second away, controllers may command the
craft to jump into a high orbit, so it will move up away from earth,
keeping orbital paths from becoming too cluttered. Others become
ensnarled in the gravity web; slowly they are drawn into gravitational
that serve as space graveyards.
A satellite for communications would really be a great antenna tower,
hundreds or even thousands of miles above the earth, capable of
transmitting messages almost instantaneously across the oceans and
continents. Soon after the launch of ATWS-6, "the Teacher in the sky", (a
satellite designed to aid people) NASA ground controllers trained its
antenna on Appalachia. There is brought evening college classes to
schoolteachers whose isolation denied opportunity for advancement.
The use of Satellites is growing rapidly and so is the different jobs
for them.
ADDITIONAL FEATURED ESSAYS
Weather Forecasting
In researching this project I was amazed to find the many books on this topic. After going through much information and
Solar Energy
Centuries ago the Greek mathematician Archimedes used sunlight to set fire to invading ships. In the following paper you
Global Positioning Systems
The new Avionics Modernization Program (AMP) systems installed in the F-111E and EF-111A have raised their share of ques
Who Was Responsible For The Cold War?
? ~Revisionist historians tend to regard the outbreak of the "Cold War" as a result of American hostility or, at least ,
The Future Of The Internet
In Today's world of computers, the internet has become part of ones regular vocabulary. The internet is everywhere, in t
|
|
|
|
