LEAVING THE PLANET BY

SPACE ELEVATOR

PRESENTED BY: PANKAJ SHARMA, 3RD YEAR, MECHANICAL ENGG DEPTT.

A BRIEF HISTORY

19th CENTURY:

The key concept of the space elevator appeared in 1895

when Russian scientist Konstantin Tsiolkovsky was inspired by the Eiffel

Tower in Paris. He considered a similar tower that reached all the way into

space and was built from the ground up to the altitude of 35,790

kilometers.

20th CENTURY:

In 1929, Authur Clarke, the famous science fiction writer and futurist, in his

novel Fountains of Paradise describes the concept of the space elevator

NEED FOR AN ALTERNATE SPACE

TRANSPORT SYSTEM

The present day space

transportation systems based

on rocket launches are:

1. Economically inefficient.

2. Involve huge risk factors.

WHAT IS A SPACE ELEVATOR?

Space elevators are

incredibly tall

theoretical structures

that stretch beyond

the earth’s

atmosphere to

transport satellites

and shuttles into outer

space without the cost

and environmental

impact of rocket

fueled launches

How could it be done?

• A space elevator made of

ribbon anchored to an offshore

sea platform

• Ribbon would stretch to a small

counterweight approximately

62,000 miles (100,000 km) into

space due to rotation of earth

about its own axis

• Mechanical lifters attached to the

ribbon would then climb the

ribbon, carrying cargo and humans

into space using different

mechanisms.

WORKING PRINCIPLE

The centrifugal force of

earth’s rotation is the

basic principle behind the

working of elevator. Due

to the earth’s rotation, the

centrifugal force acting

radially outwards help to

keep the elevator cable

taught.

MAIN COMPONENTS

The Ribbon

The Anchors

The Climbers

The Power

THE RIBBON (TETHER)

The cable in a space elevator must be

strong enough to carry its own weight

as well as the weight of the climber.

The cable should be very light and

flexible.

The required properties of the cable

material are satisfied by a recently

synthesized material known as

CARBON NANOTUBES.

WHAT IS A CARBON NANOTUBE?

A Carbon Nanotube can be

thought of as a sheet of

hexagonal lattice of carbon

rolled in the form of a

cylindrical tube with

exceptionally useful

properties.

They are also referred as

THE WONDER MATERIAL

WHY CARBON NANOTUBES?

Property Single Walled

Nanotubes

Metal wires

Tensile Strength 45 billion pascals High strength

steel alloys break

at about 2 billon

pascal

Resilience Can be bent at

large angles and

restraightened

without damage

Metals and carbon

fibers fracture at

grain boundaries

Temperature

stability

Stable upto 2800

degrees in

vacuum, 750

degrees in air

Metal wire in

microchips melt at

600 to 1000

degrees C

FABRICATION OF NANOTUBES

Techniques have been developed to produce nanotubes in sizable quantities, including

arc discharge, laser ablation, high-pressure carbon monoxide disproportionation,

and chemical vapor deposition (CVD).

Anchor

Anchor station is a mobile, ocean-going platform

identical to ones used in oil drilling.

Anchor is located in eastern equatorial pacific

(GALAPAGOS ISLANDS )

Weather and mobility are primary factors in

positioning of the anchor

Climbers

Initial ~200 climbers used to build

nano-ribbon.

Later used as launch vehicles for

payloads from 20,000- 1,000,000

kg, at velocities up to 200km/hr

Climbers powered by electron

laser & photovoltaic cells, with

power requirements of 1.4-

120MW

Power Beaming Propulsion

Free-electron lasers used to

deliver power

Adaptive Optics on Hobby-Eberly

telescope used to focus Earth-

based beams, (25cm spot @

1,000km altitude)

Reduced power delivered at high

altitudes compensated by reduced

gravitational force on climber,

(~0.1g)

Continued…

The laser will beam 2.4

megawatts of energy to

photovoltaic cells, perhaps made

of Gallium Arsenide (GaAs)

attached to the lifter,

It will then convert that energy

to electricity to be used by

conventional, niobium-magnet

DC electric motors

In 2009, NASA awarded

$900,000 to Laser Motive for

their successful demonstration of

"wireless power transmission" for

space elevator

SPACE ELEVATOR – THE FUTURE

While rockets will undoubtedly improve greatly in efficiency there is a limit to how

efficient they can become.

CURRENT

Cost of a launch $10,000 per pound ($22,000 per kg)

Huge vibrations produced and rocket fuel and hardware required

which can’t be reused .

Riding on a continuous and giant explosion is

extraordinarily dangerous

ELEVATOR

Cost of launch $250 per

pound ($660 per kg).

Less vibrations produced and less hardware required and

can be used almost every day for space travel.

Safe access to space - no explosive propellants or

dangerous launch.

Applications

Solar power satellites - economical, clean power for use on Earth

Solar System Exploration - colonization and full development of the moon, Mars and Earth orbit

Telecommunications - enables extremely high performance systems

Next Steps…

Material development efforts are

underway by private industry

Engineering development centers in

the U.S., Spain and Netherlands are

under development

Japanese construction giant

OBOYASHI CORPORATION has

undertaken the project to build a fully

functional space elevator by the year

2050.

MAJOR HURDLES

Ribbon Construction

Atmospheric:

Lightning

High Winds

Atomic Oxygen

Orbital: Meteors

Low orbit object

CONCLUSION

Space elevator can be very well understood as the future of

space travel and a technology that will help to spread the human

civilization beyond earth…..

THANK YOU