A Starway to Heaven

by Michael Martin-Smith

 

 

People familiar with the Torah or Old Testament will remember well the dream of the Patriarch, Jacob, in which he saw a ladder stretching from the ground before him up into the sky, leading directly to God’s Heaven. There must have been many astronautical humanists who must have speculated, in fantasy, upon the possibility of building such a Stairway to Heaven; indeed, long before our modern times, the Ziggurats of Ur and the Pyramids of Egypt were widely believed to have been intended precisely as Stairways to Heaven.

In 1895 the Russian Space pioneer, Konstantin Tsiolkovskii, is believed to have been the first author to have proposed a Space Tower in connection with ideas of space travel, but, recognising that there was no conceivable material with which to build such a tower, continued to base his concepts upon liquid fuelled rocket. In 1960 the Soviet engineer Yuri Artsutanov, wrote a book called “Into Space with the help of an electric locomotive” in which he proposed a vertical railroad held in place by a counterweight beyond geostationary orbit, along which an electrically driven vehicle would ride into orbit safely, regularly and cheaply drawing power only from the electricity grid. In 1966 Artsutanov popularised this idea in an article in the mass readership magazine, Sputnik, which I had the good fortune to read while at school.

In 1978, Sir Arthur C Clarke’s famous novel “Fountains of Paradise” further popularised the concept of space elevators, setting the construction of the elevator in Sri Lanka, as a near equatorial site, on the abandoned palace of an ancient Buddhist visionary ruler Although the idea a was now put on a much firmer scientific basis, and many of the issues of life support and orbital mechanics were tried and tested, the prospect of building a 62,000 mile (100,000 kilometres) cable with a gigantic counterweight out in Space still fell down on one issue- what material could form a cable thin enough and with enough tensile strength to do the job?

Asked about the project’s feasibility, Sir Arthur famously commented that the Space Elevator would become reality about 50 years after everyone stopped laughing.

It is only in the past 3-5 years that serious people have in fact stopped laughing, and the inside bet is that,as is sometimes the case, Sir Arthur has been conservative in his time estimates. In the light of very recent developments 50 years seems far too long. Indeed, active enthusiasts for the Space Elevator are no hoping for less than 20years! Indeed, Sir Arthur himself has now revised his prediction to 25 years.

What has changed?

Theory predicts that, for a cable to support its own weight at acceptable diameters for 100,000 kilometers we need a fibrous material capable of taking 65-120 Giga Pascals; for reference, the finest steel only attains 1% of this while kevlar (a material used in body armour) can achieve at best 5GPa.

For a 20 tons payload to be ferried up to Geostationary Orbit by such a cable would require a 600 tons counterweight at 100,000 kms to provide centrifugal force necessary to turn the cable into a railroad.

Within the past 3 years a material has been fabricated which can potentially deliver 50 - 100 GPa (50- 100 times stronger than steel, and lighter than fibreglass) and so, in theory, can be developed to achieve the full strength required. This is a new form of carbon - the carbon nanotube, which potentially possesses the strength and lightness to be formed into a space elevator cable. Carbon Nanotubes, first discovered in 1979, are no coming of age. A carbon nanotube is a lattice of carbon atoms which has been rolled up into a cylinder, of only a few nanometres in diameter These can be woven together or made into multiwalled tubes. Research into the best structure and manufacturing processes for carbon nanotubes cables in bulk is underway, and expected to demonstrate the required capacities within 2-3 years At present, manufacturing is only possible on a small scale for research purposes but in April this year, a team (the Liftport Group) has been formed by Dr Bradley Edwards to investigate and develop all the technologies for Space Elevator construction; this includes the formation, in June 2005, of a company (Liftport Nanotech) at Millville New Jersey specifically aimed at developing and manufacturing carbon nanotubes on an industrial scale; initially such products would be used for Research & Development with a view to terrestrial applications, for example quantum electronic devices, nanotechnology, ultrabright light sources for telecomms, sensors, aerospace, and automobile industries, and, when linked with monoclonal antibodies, the detection and treatment of cancer; this would generate revenues before space elevators themselves are possible.

Already work in the shape of annual Space Elevator conferences and papers is addressing the many practical issues in building and operating a Space Elevator- eg launch sites (Dr Edwards favours a floating platform located at or near the equator) failure and collision modes, corrosion, micrometeorites, security, radiation from the van Allen Belts on the way up. It is anticipated that by 2008 all the major issues will have been addressed with solutions researched, and that given funding of $5-10 billions the first prototype cargo carrying space elevator could be operational in 2018.

It is envisaged that the first elevator would be a very thin ribbon weighing a kilogram per kilometre would be ferrying 5 tons per day, with a 13 tons counterweight. This in turn would haul up additional cables, so that in effect the cable would grow, as traffic required. Eventually, if and when passengers were carried- eg to a Geostationary orbiting hotel, resort or health farm (whatever!) the journey would take about a week and cost about $50,000.The GEO hotel would also function as a jump-off point for the Moon, Mars and elsewhere- where corresponding space elevators would, in time, be created.

Several first steps have been taken already. On September 20th this year, Liftport demonstrated the idea of lifting a payload along a very thin cable to 1000 feet (300 metres) altitude and plan over coming months to extend this to 5,000 feet (1,500 metres).

Space Elevator Prizes

Meanwhile NASA, following in the X Prize Foundation’s footsteps is offering annual prizes for advances in beamed energy and tethered lifting technology, beginning this year, while the Spaceward Foundation is launching an annual competition to, to advance space elevator technology development, in which climber designs are sent up a thin cable by beamed electric power. The first Space Elevator Games were held under NASA- Ames auspices in October 2005 and promise to become an annual event. It is expected that cable materials will increase annually in tensile strength and lightness under the stimulus of Prize driven competition.

Meanwhile, Dr Brad Edwards and the Liftport Group are ploughing their own more commercial furrow, with the launch of several companies tackling the nut and bolts of a new industry.

In summary it would appear that the Space Elevator thanks to the emergence of new materials science the stimulus of prizes and commercial product development, together with the problems of orthodox access to Space, is an Idea whose time is come.

We are now in the “Wrights Brothers” era of a whole new route to Space and all its promise, with every reason to hope that, as in the days of pioneering aviation, the pace of development will astound us all.

Welcome to the future!

[032. MMS. TDF. 2005 - 01. 01. 2006]