FREE ESSAY ON SATELLITES

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 Page 2 ------ 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.