STARSHIPS 167
In 1957 Russian scientist Yuri Artsutanov proposed a new solution,
that the space elevator be built in reverse order, top-down, starting
from outer space. He envisioned a satellite in a geostationary orbit
36,000 miles in space, where it would appear to be stationary, and
from which one would drop a cable down to Earth. Then the cable
would be anchored to the ground. But the tether for a space elevator
would have to be able to withstand roughly 60-100 gigapascals (gpa)
of tension. Steel breaks at about 2 gpa, making the idea beyond reach.
The idea of a space elevator reached a much wider audience with
the publication of Arthur C. Clarke's 1979 novel, The Fountains of Paradise, and Robert Heinlein's 1982 novel, Friday. But without any further progress, the idea languished.
The equation changed significantly when carbon nanotubes were developed by chemists. Interest was suddenly sparked by the work of
Sumio Iijima of Nippon Electric in 1991 (although evidence for carbon
nanotubes actually dates back to the 1950s, a fact that was ignored at
the time). Remarkably, nanotubes are much stronger than steel cables,
but also much lighter. In fact, they exceed the strength necessary to
maintain a space elevator. Scientists believe a carbon nanotube fiber
could withstand 120 gpa of pressure, which is comfortably above the
breaking point. This discovery has rekindled attempts to create a space
elevator.
In 1999 a NASA study gave serious consideration to the space elevator, envisioning a ribbon, about 1 meter wide and about 47,000 kilometers long, capable of transporting about 15 tons of payload into
Earth's orbit. Such a space elevator could change the economics of
space travel overnight. The cost could be reduced by a factor of ten
thousand, an astonishing, revolutionary change.
Currently it costs $10,000 or more to send a pound of material into
orbit around the Earth (roughly the cost, ounce for ounce, of gold).
Each Space Shuttle mission, for example, costs up to $700 million. A
space elevator could reduce the cost to as little as $1 per pound. Such
a radical reduction in the cost of the space program could revolution-
In 1957 Russian scientist Yuri Artsutanov proposed a new solution,
that the space elevator be built in reverse order, top-down, starting
from outer space. He envisioned a satellite in a geostationary orbit
36,000 miles in space, where it would appear to be stationary, and
from which one would drop a cable down to Earth. Then the cable
would be anchored to the ground. But the tether for a space elevator
would have to be able to withstand roughly 60-100 gigapascals (gpa)
of tension. Steel breaks at about 2 gpa, making the idea beyond reach.
The idea of a space elevator reached a much wider audience with
the publication of Arthur C. Clarke's 1979 novel, The Fountains of Paradise, and Robert Heinlein's 1982 novel, Friday. But without any further progress, the idea languished.
The equation changed significantly when carbon nanotubes were developed by chemists. Interest was suddenly sparked by the work of
Sumio Iijima of Nippon Electric in 1991 (although evidence for carbon
nanotubes actually dates back to the 1950s, a fact that was ignored at
the time). Remarkably, nanotubes are much stronger than steel cables,
but also much lighter. In fact, they exceed the strength necessary to
maintain a space elevator. Scientists believe a carbon nanotube fiber
could withstand 120 gpa of pressure, which is comfortably above the
breaking point. This discovery has rekindled attempts to create a space
elevator.
In 1999 a NASA study gave serious consideration to the space elevator, envisioning a ribbon, about 1 meter wide and about 47,000 kilometers long, capable of transporting about 15 tons of payload into
Earth's orbit. Such a space elevator could change the economics of
space travel overnight. The cost could be reduced by a factor of ten
thousand, an astonishing, revolutionary change.
Currently it costs $10,000 or more to send a pound of material into
orbit around the Earth (roughly the cost, ounce for ounce, of gold).
Each Space Shuttle mission, for example, costs up to $700 million. A
space elevator could reduce the cost to as little as $1 per pound. Such
a radical reduction in the cost of the space program could revolution-