The Space Elevator
This apparently outrageous concept was first presented to the West in a letter in the issue of Science for 11 February 1966, “Satellite Elongation into a True 'Sky-Hook' ", by John D. Isaacs, Hugh Bradner and George B. Backus of Scripps Institute of Oceanography, and Allyn C. Vine of Wood's Hole Oceanographic Institute. Though it may seem odd that oceanographers should get involved with such an idea, this is not surprising when one realises that they are about the only people (since the great days of barrage balloons) who concern themselves with very long cables hanging under their own weight. (Dr. Allyn Vine's name, incidentally is now immortalised in that of the famous research submersible “Alvin”.) It was later discovered that the concept had already been developed six years earlier – and on a much more ambitious scale – by a Leningrad engineer, Y. N. Artsutanov (Komsomolskaya Pravda, 31 July 1960). Artsutanov considered a “heavenly funicular”, to use his engaging name for the device, lifting no less than 12,000 tons a day to synchronous orbit. It seems surprising that this daring idea received so little publicity; the only mention I have ever seen of it is in the handsome volume of paintings by Alexei Leonov and Sokolov, The Stars are Awaiting Us (Moscow 1967). One colour plate (page 25) shows the “Space Elevator” in action; the caption reads: ". . . the satellite will, so to say, stay fixed in a certain point in the sky. If a cable is lowered from the satellite to the earth you will have a ready cable-road. An 'Earth-Sputnik-Earth' elevator for freight and passengers can then be built, and it will operate without any rocket propulsion.”
Although General Leonov gave me a copy of his book at the Vienna “Peaceful Uses of Space” Conference in 1968, the idea simply failed to register on me – despite the fact that the elevator is shown hovering exactly over Sri Lanka! I probably thought that Cosmonaut Leonov, a noted humorist*, was just having a little joke.
– – – – – – – -
* Also a superb diplomat. After the Vienna screening he made quite the nicest comment on 2001 I've ever heard: “Now I feel I've been in space twice.” Presumably after the Apollo-Soyuz mission he would say “three times”.
– – – – – – – -
The space elevator is quite clearly an idea whose time has come, as is demonstrated by the fact that within a decade of the 1966 Isaacs letter it was independently re-invented at least three times. A very detailed treatment, containing many new ideas, was published by Jerome Pearson of Wright-Paterson Air Force Base in Acta Astronautica for September-October 1975 ("The Orbital Tower; a spacecraft launcher using the Earth's rotational energy"). Dr. Pearson was astonished to hear of the earlier studies, which his computer survey had failed to locate; he discovered them through reading my own testimony to the House of Representatives Space Committee in July 1975. (See The View From Serendip.)
Six years earlier (Journal of the British Interplanetary Society, Vol. 22, pp. 442-457, 1969) A. R. Collar and J. W. Flower had come to essentially the same conclusions in their paper “A (Relatively) Low Altitude 24-hour Satellite”. They were looking into the possibility of suspending a synchronous communications satellite far below the natural 36,000 kilometre altitude, and did not discuss taking the cable all the way down to the surface of the earth, but this is an obvious extension of their treatment.
And now for a modest cough. Back in 1963, in an essay commissioned by UNESCO and published in Astronautics for February 1964, “The World of the Communications Satellite” (now available in Voices From the Sky), I wrote: “As a much longer term possibility, it might be mentioned that there are a number of theoretical ways of achieving a low-altitude, twenty-four-hour satellite; but they depend upon technical developments unlikely to occur in this century. I leave their contemplation as an exercise for the student.”
The first of these “theoretical ways” was, of course, the suspended satellite discussed by Collar and Flower. My crude back-of-an-envelope calculations, based on the strength of existing materials, made me so sceptical of the whole idea that I did not bother to spell it out in detail. If I had been a little less conservative – or if a larger envelope had been available – I might have been ahead of everyone except Artsutanov himself.
As this book is (I hope) more of a novel than an engineering treatise, those who wish to go into technical details are referred to the now rapidly expanding literature on the subject. Recent examples include Jerome Pearson's “Using the Orbital Tower to Launch Earth-Escape Payloads Daily” (Proceedings of the 27th International Astronautical Federation Congress, October 1976) and a remarkable paper by Hans Moravec, “A Non-Synchronous Orbital Skyhook” (American Astronautical Society Annual Meeting, San Francisco, 18-20 October 1977).
I am much indebted to my friends the late A. V. Cleaver of Rolls-Royce, Dr. Ing. Harry 0. Ruppe, Professor of Astronautics at the Technical University of Munich's Lehrstuhl für Raumfahrttechnic, and Dr. Alan Bond of the Culham Laboratories for their valuable comments on the Orbital Tower. They are not responsible for my modifications.
Walter L. Morgan (no relation to Vannevar Morgan, as far as I know) and Gary Gordon of the COMSAT Laboratories, as well as L. Perek of the United Nations' Outer Space Affairs Division, have provided most useful information on the stable regions of the synchronous orbit; they point out that natural forces (particularly sun-moon effects) would cause major oscillations, especially in the north-south directions. Thus “Taprobane” might not be as advantageous as I have suggested; but it would still be better than anywhere else.
The importance of a high-altitude site is also debatable, and I am indebted to Sam Brand of the Naval Environmental Prediction Research Facility, Monterey, for information on equatorial winds. If it turns out that the Tower could be safely taken down to sea level, then the Maldivian island of Gan (recently evacuated by the Royal Air Force) may be the twenty-second century's most valuable piece of real estate.
Finally, it Seems a very strange – and even scary – coincidence that, years before I ever thought of the subject of this novel, I myself should have unconsciously gravitated (sic) towards its locale. For the house I acquired a decade ago on my favourite Sri Lankan beach (see The Treasure of the Great Reef and The View From Serendip) is at precisely the closest spot on any large body of land to the point of maximum geosynchronous stability.
So in my retirement I hope to watch the other superannuated relics of the Early Space Age, milling around in the orbital Sargasso Sea immediately above my head.
And now, one of those extraordinary coincidences I have learned to take for granted.
While correcting the proofs of this novel, I received from Dr. Jerome Pearson a copy of NASA Technical Memorandum TM-75174, “A Space 'Necklace' About the Earth” by G. Polyakov. This is a translation of “Kosmicheskoye 'Ozherel'ye' Zemli”, published in Teknika Molodezhi, No 4, 1977, pp. 41-43.
In this brief but stimulating paper, Dr. Polyakov, of the Astrakhan Teaching Institute, describes in precise engineering details Morgan's final vision of a continuous ring around the world. He sees this as a natural extension of the space elevator, whose construction and operation he also discusses in a manner virtually identical with my own treatment.
I salute tovarich Polyakov, and am beginning to wonder if – yet again, I have been too conservative. Perhaps the Orbital Tower may be an achievement of the twenty-first century, not the twenty-second.
Our own grandchildren may demonstrate that – sometimes – Gigantic is Beautiful.
18 September 1978