As I posted a couple of years back, our work on nanotubes and graphene was
making the space elevator a plausible proposition. Here we are with some calculations that
indicate that it could be possible.
Certainly, this is needed to produce and support a large space station
properly constructed to produce artificial gravity and best positioned at GSO
to allow easy launches into interplanetary voyages.
Right now the technology has been demonstrated and may be even improved. How about continuous nested nanotubes? A series of coils could be taken up into
space and the cable produced from them there, or alternately, they could be
grown there. Once one cable touches down
the balance then have a guide. The first
cable may just be easy enough to pull off.
We still need to think out operating speed. It may well need two cables to achieve the necessary
efficiency and it needs to default correctly in the event of power failure.
An Escalator To Space - Not Very Far
Away
by Staff
Writers
According to A. Senthil 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 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.
No comments:
Post a Comment