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Chennai: The day may
not be far away when an elevator attendant asks your preferred
destination - low earth orbit (LEO) or geostationary orbit (GSO).
Research is fast progressing in advanced countries on designing a
space elevator, according to an Indian space expert.
"Space scientists and engineers are looking at the possibility of
designing an elevator to travel into space. It is also time that
Indian research institutions looked at developing carbon nanotube
composite fibre, nano epoxy and laser power beaming," A. Senthil
Kumar, deputy head at the Vikram Sarabhai Space Centre (VSSC),
told IANS in an interview.
VSSC is part of the Indian Space Research Organisation (ISRO).
Kumar, who addressed the 98th Indian Science Congress that
concluded Friday, said: "The space elevator consists of a cable
from an anchor in the ground to a counter weight located beyond
geostationary orbit (GSO) that is 35,786 km away. A climber will
move up on a carbon nanotube tether between earth and space."
The space lift would be utilised as a transportation and utility
system for moving people, satellites and other items from earth to
space.
According to Kumar, once the infrastructure comes into position,
the cost of carrying anything from earth to the GSO will be
reduced to less than $250 per kg from the current $40,000 per kg.
"The elevator can travel at 200 km per hour and reach the GSO in
eight days," Kumar said.
He said 94 percent weight of the conventional rockets consists of
fuel and other expendable infrastructure.
"What space agencies are looking at is safe access to the space at
low cost," Kumar said.
He said a tall building on earth could be the anchor, from which a
tether made of carbon nanotube composite fabric would extend to
about 50,000 km towards the heaven.
"A climber/elevator powered by laser beaming of energy can travel
over this tether. The payloads can be transported using these
climbers to different orbits," Kumar said.
Speaking about the rope on which the climber would go up, the
scientist said theoretically the carbon nanotube has a tensile
strength of 300 gigapascal whereas the required strength for space
travel is only 130 gigapascal.
The carbon nano fibres currently developed has tensile up to five
gigapascal.
"The cable will be thickest at the top and taper down towards the
earth. First a satellite will take the cable to the space
wherefrom it will be unrolled towards the earth. The cable could
be brought down without much movement and tied to the base
station," Kumar explained.
And the challenges?
"Radiation, lightning, wind, meteors, space debris...but these are
issues that can be dealt with," Kumar said.
(Venkatachari Jagannathan can be contacted at v.jagannathan@ians.in)
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