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that cannot weigh more than 2 grams and must carry 50 percent more
weight than the best tether of the previous year. The challenge is intended to stimulate research in developing lightweight materials
strong enough to be strung 100,000 kilometers in space. There are
prizes worth $150,000, $40,000, and $10,000. (To highlight the difficulty
of mastering this challenge, in 2005, the first year of the competition,
no one won a prize.)
Although a successful space elevator could revolutionize the space
program, such machines have their own sets of hazards. For example,
the trajectory of near-Earth satellites constantly shifts as they orbit the
Earth (this is because the Earth rotates beneath them). This means
that these satellites would eventually collide with the space elevator at
18,000 miles per hour, sufficient to rupture the tether. To prevent such
a catastrophe, in the future either satellites will have to be designed to
include small rockets so that they can maneuver around the space elevator, or the tether of the elevator might have to be equipped with
small rockets to evade passing satellites.
Also, collisions with micrometeorites are a problem, since the
space elevator is far above the atmosphere of the Earth, and our atmosphere usually protects us from meteors. Since micrometeor collisions
are unpredictable, the space elevator must be built with added shielding and perhaps even fail-safe redundancy systems. Problems could
also emerge from the effects of turbulent weather patterns on the
Earth, such as hurricanes, tidal waves, and storms.
THE SLINGSHOT EFFECT
Another novel means of hurling an object near the speed of light is
to use the "slingshot" effect. When sending space probes to the outer
planets, NASA sometimes whips them around a neighboring planet, so
they use the slingshot effect to boost their velocity. NASA saves on valuable rocket fuel in this way. That's how the Voyager spacecraft was able
to reach Neptune, which lies near the very edge of the solar system.
that cannot weigh more than 2 grams and must carry 50 percent more
weight than the best tether of the previous year. The challenge is intended to stimulate research in developing lightweight materials
strong enough to be strung 100,000 kilometers in space. There are
prizes worth $150,000, $40,000, and $10,000. (To highlight the difficulty
of mastering this challenge, in 2005, the first year of the competition,
no one won a prize.)
Although a successful space elevator could revolutionize the space
program, such machines have their own sets of hazards. For example,
the trajectory of near-Earth satellites constantly shifts as they orbit the
Earth (this is because the Earth rotates beneath them). This means
that these satellites would eventually collide with the space elevator at
18,000 miles per hour, sufficient to rupture the tether. To prevent such
a catastrophe, in the future either satellites will have to be designed to
include small rockets so that they can maneuver around the space elevator, or the tether of the elevator might have to be equipped with
small rockets to evade passing satellites.
Also, collisions with micrometeorites are a problem, since the
space elevator is far above the atmosphere of the Earth, and our atmosphere usually protects us from meteors. Since micrometeor collisions
are unpredictable, the space elevator must be built with added shielding and perhaps even fail-safe redundancy systems. Problems could
also emerge from the effects of turbulent weather patterns on the
Earth, such as hurricanes, tidal waves, and storms.
THE SLINGSHOT EFFECT
Another novel means of hurling an object near the speed of light is
to use the "slingshot" effect. When sending space probes to the outer
planets, NASA sometimes whips them around a neighboring planet, so
they use the slingshot effect to boost their velocity. NASA saves on valuable rocket fuel in this way. That's how the Voyager spacecraft was able
to reach Neptune, which lies near the very edge of the solar system.