SOURCES AND ACKNOWLEDGEMENTS

SOURCES

Chapter 1: The Kuiper Belt

For a description of Captain Chandler's hunting ground, discovered as recently as 1992, see 'The Kuiper Belt' by Jane X. Luu and David C. Jewitt (Scientific American, May 1996)

Chapter 3: Rehabilitation

I believed that I had invented the palm-to-palm transfer of information, so it was mortifying to discover that Nicholas ("Being Digital") Negroponte (Hodder and Stoughton, 1995) and his MIT Media Lab have been working on the idea for years...

Chapter 4: Star City

The concept of a 'ring around the world' in the geostationary orbit (CEO), linked to the Earth by towers at the Equator, may seem utterly fantastic but in fact has a firm scientific basis. It is an obvious extension of the 'space elevator' invented by the St Petersburg engineer Yuri Artsutanov, whom I had the pleasure of meeting in 1982, when his city had a different name.

Yuri pointed out that it was theoretically possible to lay a cable between the Earth and a satellite hovering over the same spot on the Equator which it does when placed in the CEO, home of most of today's communications satellites. From this beginning, a space elevator (or in Yuri's picturesque phrase, 'cosmic funicular') could be established, and payloads could be carried up to the CEO purely by electrical energy. Rocket propulsion would be needed only for the remainder of the journey.

In addition to avoiding the danger, noise and environmental hazards of rocketry, the space elevator would make possible quite astonishing reductions in the cost of all space missions. Electricity is cheap, and it would require only about a hundred dollars' worth to take one person to orbit. And the round trip would cost about ten dollars, as most of the energy would be recovered on the downward journey! (Of course, catering and inflight movies would put up the price of the ticket. Would you believe a thousand dollars to CEO and back?)

The theory is impeccable: but does any material exist with sufficient tensile strength to hang all the way down to the Equator from an altitude of 36,000 kilometres, with enough margin left over to raise useful payloads? When Yuri wrote his paper, only one substance met these rather stringent specifications – crystalline carbon, better known as diamond. Unfortunately, the necessary megaton quantities are not readily available on the open market, though in "2061: Odyssey Three" I gave reasons for thinking that they might exist at the core of Jupiter. In "The Fountains of Paradise" I suggested a more accessible source – orbiting factories where diamonds might be grown under zero-gravity conditions.

The first 'small step' towards the space elevator was attempted in August 1992 on the Shuttle Atlantis, when one experiment involved the release – and retrieval – of a payload on a 21-kilometre-long tether. Unfortunately the playing-out mechanism jammed after only a few hundred metres.

I was very flattered when the Atlantis crew produced The Fountains of Paradise during their orbital press conference, and Mission Specialist Jeffrey Hoffman sent me the autographed copy on their return to Earth.

The second tether experiment, in February 1996, was slightly more successful: the payload was indeed deployed to its full distance, but during retrieval the cable was severed, owing to an electrical discharge caused by faulty insulation. This may have been a lucky accident – perhaps the equivalent of a blown fuse:

I cannot help recalling that some of Ben Franklin's contemporaries were killed when they attempted to repeat his famous – and risky – experiment of flying a kite during a thunderstorm.

Apart from possible dangers, playing-out tethered payloads from the Shuttle appears rather like fly-fishing: is not as easy as it looks. But eventually the final 'giant leap' will be made – all the way down to the Equator.

Meanwhile, the discovery of the third form of carbon, buckminsterfullerene (C60) has made the concept of the space elevator much more plausible. In 1990 a group of chemists at Rice University, Houston, produced a tubular form of C60 – which has far greater tensile strength than diamond. The group's leader, Dr Smalley, even went so far as to claim it was the strongest material that could ever exist – and added that it would make possible the construction of the space elevator.

(Stop Press News: I am delighted to know that Dr Smalley has shared the 1996 Nobel Prize in Chemistry for this work.)

And now for a truly amazing coincidence – one so eerie that it makes me wonder Who Is In Charge.

Buckminster Fuller died in 1983, so never lived to see the discovery of the 'buckyballs' and 'buckytubes' which have given him much greater posthumous fame. During one of the last of his many world trips, I had the pleasure of flying him and his wife Anne around Sri Lanka, and showed them some of the locations featured in The Fountains of Paradise. Shortly afterwards, I made a recording from the novel on a 12" (remember them?) LP record (Caedmon TC 1606) and Bucky was kind enough to write the sleeve notes. They ended with a surprising revelation, which may well have triggered my own thinking about 'Star City':

'In 1951 I designed a free-floating tensegrity ring-bridge to be installed way out from and around the Earth's equator. Within this "halo" bridge, the Earth would continue its spinning while the circular bridge would revolve at its own rate. I foresaw Earthian traffic vertically ascending to the bridge, revolving and descending at preferred Earth loci'

I have no doubt that, if the human race decides to make such an investment (a trivial one, according to some estimates of economic growth), 'Star City' could be constructed. In addition to providing new styles of living, and giving visitors from low-gravity worlds like Mars and the Moon better access to the Home Planet, it would eliminate all rocketry from the Earth's surface and relegate it to deep space, where it belongs (Though I hope there would be occasional anniversary re-enactments at Cape Kennedy, to bring back the excitement of the pioneering days.)

Almost certainly most of the City would be empty scaffolding, and only a very small fraction would be occupied or used for scientific or technological purposes. After all, each of the Towers would be the equivalent of a ten-million-floor skyscraper – and the circumference of the ring around the geostationary orbit would be more than half the distance to the Moon! Many times the entire population of the human race could be housed in such a volume of space, if it was all enclosed. (This would pose some interesting logistics problems, which I am content to leave as 'an exercise for the student'.)

Chapter 5: Education

I was astonished to read in a newspaper on 19 July 1996 that Dr Chris Winter, head of British Telecom's Artificial Life Team, believes that the information and storage device I described in this chapter could be developed within 30 years! (In my 1956 novel The City and the Stars I put it more than a billion years in the future... obviously a serious failure of imagination.) Dr Winter states that it would allow us to 'recreate a person physically, emotionally and spiritually', and estimates that the memory requirements would be about 10 terabytes (10e13 bytes), two orders of magnitude less than the petabyte (10e15 bytes) I suggest.

And I wish I'd thought of Dr Winter's name for this device, which will certainly start some fierce debates in ecclesiastical circles: the 'Soul Catcher'... For its application to interstellar travel, see following note on Chapter 9.

For an excellent history of the 'Beanstalk' concept (as well as many other even farther-out ideas such as anti-gravity and space-warps) see Robert L. Forward's "Indistinguishable From Magic" (Baen 1995).