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- Michael Majchrowicz, student @ University of Kentucky
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
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
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.
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Spaceflight, Remote sensing, Satellite, Unmanned spacecraft, Communications satellite, Earth orbits, Astrodynamics
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