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- Section 1 -- Question 4
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- Satellites orbit the earth doing our bidding in ways
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- that enrich the lives of almost all of us.
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- Through electronic eyes from hundreds of miles overhead, they
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- lead prospectors to mineral deposits invisble on earth's surface.
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- Relaying communications at the speed of light, they shrink the planet
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- until its most distant people are only a split second apart.
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- They beam world weather to our living room TV and guide ships
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- through storms. Swooping low over areas of possible hostility, spies
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- in the sky maintain a surveillance that helps keep peace in a
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- volatile world.
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- How many objects, exaclty, are orbiting out there?
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- Today's count is 4,914.
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- The satellites begin with a launch, which in the U.S. takes place at
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- Cape Canaveral in Florida, NASA's Wallops Flight Center in Virginia,
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- or, for polar orbiters, Vandenberg Air Force Base in California.
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- One satellite in 20 is crippled by the jolt of lift-off, or dies
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- in the inferno of a defective rocket blast, or is thrust into
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- improper orbit. A few simply vanish into the immensity of space.
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- When a satellite emerges from the rocket's protective shroud,
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- radiotelemety regularly reports on its health to round-the-clock
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- crews of ground controllers. They watch over the temperatures and
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- voltages of the craft's electronic nervous system and other
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- vital "organs", always critical with machines whose sunward side may
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- be 300 degress hotter than the shaded part.
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- Once a satellite achieves orbit--that delicate condition in which
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- the pull of earth's gravity is matched by the outward fling of the
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- crafts speed--subtle pressures make it go astray. Solar flares
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- make the satellite go out of orbit. Wisps of outer atmosphere drag
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- its speed. Like strands of spiderweb, gravity feilds of the earth,
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- moon, and sun tug at the orbiting spacefarer. Even the sunshine's
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- soft caress exerts a gentle nudge.
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- Should a satellite begin to wander, ground crews fire small fuel jets
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- that steer it back on course. This is done sparingly, for exhaustion
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- of these gases ends a craft's useful career.
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- Under such stresses, many satellites last 2 years. When death is
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- only a second away, controllers may command the craft to jump into
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- a high orbit, so it will move up away from earth, keeping orbital
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- paths from becoming too cluttered. Others become ensnarled in the
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- gravity web; slowly they are drawn into gravitational that serve
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- as space graveyards.
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- A satellite for communications would really be a great antenna tower,
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- hundreds or even thousands of miles above the earth, capable of
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- transmitting messages almost instantaneously across the oceans and
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- continents.
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- Soon after the launch of ATWS-6, "the Teacher in the sky", (a satellite
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- designed to aid people) NASA ground controllers trained its antenna on
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- Appalachia. There is brought evening college classes to schoolteachers
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- whose isolation denied opportunity for advancement.
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- The use of Satellites is growing rapidly and so is the different
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- jobs for them.
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