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.