Space elevator

A little review about that concept that is looking more and more likely to happen in a close future.

What is a space elevator?

It consist of a lift hanged on a cable long enough  to reach the geostationary orbit. The concept to has been imagined by Arthur C. Clark in his book "The fountain of paradise".  

What are the reasons to build one?

Potentially, it would ease a lot the earth-low orbit journey and subsequently result in dramatically decreased of the cost of sending object into space.  At the moment, it is estimated that it cost between $4,500 and $6,500 a pound to reach low-earth orbit. The space elevator could decrease the cost by a factor 100 to 1000. It would also allows frequent journeys transporting freight or people in the two directions. The space exploration would leave the scientific exploration to industrial age. 

How to build space elevator?

Of course, the big problem is to produce a cable long and resistant enough. It is estimated that the tensile strength required to hanged the cable form geostationary orbit to ground is one trillion higher than the available material.

Geostationary Orbiting Tether "Elevator"

Two possibilities seems likely to overcome this problem:

• Designing new material with better tensile strength. A great hope in this area came from the discovery of a new carbon-based material. A little return to your chemistry lectures will remind you that Carbon can form diamond, the hardest material we know. A new state of organisation for carbon-based compound named nanotubes could potentially be used to produce extremely resistant cable.

• Another possibility would be to rethink the design of the space elevator and build a rotating tether that would rotate at the same speed as earth but without any attachment to the ground. The connection will be achieved using big plane. This solution avoid a very long cable because the attachment site would fly at 12 km of the ground hanged at the end of a 2200 km leash.

Rotating Tether "Elevator"

When are we going to take a lift?

Good question, if you believe Institute for Scientific research (ISR) or Liftport, the first space elevator, built around the geostationary orbit tether model, could be running in 15 years. However, they rely heavily on the mass production of nanotubes, which at the moment reach only a few centimetres.  The first cable aimed to be 91,000 km, so there are some more efforts required, notably because it has to be flawless. Everybody who has experienced scientific research know that research is by nature totally unpredictable. Funnily, ISR is reporting Chinese research works to elaborate their project, so I guess that Chinese are probably thinking to build their own lift.

How much is it going to cost?

There are still a lot of unknown, such as the nanotube production, or any unexpected problems during the building, but the first cable is estimated around $40b, the second around $15b. The big issue is who is going to be the first, because the first cable will have a tremendous advantage over any other contestant, notably to build a lot of other very quickly. 

Potential consequences

It's always hard to predict, but it is by far a more significant move that the first step on the moon by Armstrong. It means that space tourism is going to occur on  a large scale, solar system is accessible,  industrial can start thinking of exploiting space for resources and production. It will also mean some risk, in this time of terrorism, could you imagine what could happen if the bad people would use it? Even if I am not a religious person, I can't prevent myself thinking of the tower of Babel... 

Why are you annoying me with that?

I wish this is going to happen, if there is space tourism available in 20 years, I have just enough time to save enough money to buy a week end on orbit. If not, I will die just before it will be available...

References:

Official publication

Space cast 2020 report about space lift unconventional approach

Flight project directorate

Press

www.spacedaily.com/

http://www.zadar.net/space-elevator/

techtv.com

sciencentralnews

The space elevator come closer to reality

To the moon in a space elevator

Space elevator take off (12/08/2002)

Websites

liftwatch

Liftport

Institute for scientific research

http://www.spaceelevator.com/

Book

The Fountains of paradise
by Arthur C. Clark (1979)

The Space Elevator: A Revolutionary Earth-to-Space Transportation System
by Bradley C. Edwards (Illustrator), Eric A. Westling