Arthur C. Clarke
Interplanetary Flight
Berkley, Paperback, 1985.
12mo. xiv+164 pp. Note on 1985 Printing [ix-xi] and Preface [xiii-xiv] by Arthur Clarke.
First published, 1950.
Revised edition, 1960.
Berkley edition (1950 version), 1985.
Contents
Note on 1985 Printing
Preface
Chapter I
Historical Survey
Chapter II
The Earth's Gravitation Field
Chapter III
The Rocket
Chapter IV
The Problem of Escape by Rocket
Chapter V
The Earth-Moon Journey
Chapter VI
Interplanetary Flight
Chapter VII
The Atomic Rocket
Chapter VIII
Spaceships and Space Stations
Chapter IX
Subsidiary Problems
Chapter X
Opening Frontiers
Mathematical Appendix
Bibliography
Index
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This is a book of considerable historical importance. Reportedly, it was the first volume in English to discuss in some detail space flight as a very real opportunity, not far-fetched science fiction; Carl Sagan himself has said that the book had great influence over him, changing his whole future. Perhaps most importantly, though, Interplanetary Flight was Arthur Clarke's first published book. Its unexpected success, at least for a fairly technical non-fiction in a dangerously speculative field, prompted the writing of the more popular The Exploration of Space (1951) whose remarkable success convinced Arthur to turn himself into a professional writer. During the second half of the 1940s he had written a number of short stories, and even his debut novel (Prelude to Space, written in 1947, published in 1951), but only in the early 1950s did he take up writing seriously. The rest, of course, is history. For the next nearly five decades Clarke produced some twenty novels, nearly a hundred short stories and countless essays that have made him a household name all over the world.
Let me make this clear before it's too late. This little book has a great deal more to offer than mere historical significance. That in itself is no doubt fascinating, all the more so since it was first published seven years before the Space Age was to begin, but the real value of the book lies in the extraordinarily lucid explanation of ABC of astronautics. But make no mistake: the style is considerably more serious and more technical than Clarke's later non-fiction works. Nevertheless, the book retains from the cover to cover the most important quality that popular science should possess: perfect clarity, easily accessible for the layman if he takes the trouble to think. There are quite a few formulas in the text, as well as 13 figures and 6 tables for that matter, but the mathematics are largely confined to the appendix specially designed for the purpose. If you have trouble, as I do, with differential equations, you may well find this Mathematical Appendix a pretty tough read. But the rest of the book is wonderfully comprehensible for everybody who knows the unit for gravity. Everything else is patiently and lucidly explained. To be sure, this is no light read; it does require serious attitude and application. But it is eminently worthwhile.
It's a bizarre world that Arthur invites you to look at closely. Vacuum and weightlessness are weird enough, but there are also escape and orbital velocities, differently shaped orbits, mass ratios, exhaust velocities and numerous other exotic notions. Isn't it strange, to say the least, that you need less energy to reach the Moon from the Earth than you need to travel to Mars from the same place? Isn't it even stranger, almost ludicrous to be exact, that you can leave the Solar System more easily from Mercury than from Jupiter, even though at first glance it really should be the other way round? Yet these funny hypothetical situations have their perfectly logical explanations. Indeed this is one of the scariest yet most compelling things about space: the inexorable laws of celestial mechanics (so charmingly explained and illustrated here). Just imagine ''parking'' something in a stable orbit - it will continue orbiting forever! Or, better still, imagine that your rocket brakes just fail on your way down through our atmosphere: it might give some slight satisfaction to know the exact velocity with which you are going to smash yourself onto the surface: 11,2 km/sec; the good news is that it would be perfectly painless. Yet another mind-stretching consequence of reading this book is to convince you that the key word for space is motion; it may often be a slow motion, but nothing ever stands still - forget all those motionless images you have seen on the movies; highly misleading stuff. This is how it will look in the space itself, but not because you just ''stand still'', but because you move with the same orbital velocity as everything around you. Similar velocities on Earth would easily kill due to the considerable weight of our air, yet the vacuum is altogether a different affair, almost unimaginably so. (Check Clarke's terrific short story ''Maelstrom II'' for some imaginative uses of these things in fiction.)
Since I understand nothing of rocketry and astronomy, I cannot tell you how dated this book is; if you have some friends in NASA, I suggest you ask them. But I surmise, since it deals almost entirely with basics, it is very little dated. More often, when it discusses lunar exploration for instance, the book is, alas, still ahead of our times. Besides, if you happen to be a layman like myself, you can play a most fascinating game called ''read more and learn how dated your book really is''. Have we, for instance, mastered the atomic drive already, at least the dirty fission kind? Or do space stations with permanent crews in Earth's orbit already exist? This will take a good deal of browsing in Wikipedia, but it is bound to be fun. Last but not least, let me repeat this: by the present Brysovian standards of popular science, this is a pretty tough read; but considering the degree of intentional technical difficulty, it has clarity and lucidity that are seldom found in far simpler pop-science discussions. So don't be discouraged by the numerous formulas and diagrams; just study them carefully. The Mathematical Appendix you are well advised to skip completely at first reading. Enjoy the rest. It's a jolly exciting ride through time and space.
P.S. A note on the Berkley edition. Now, this is the right edition to have. It has a very nice, new (1985) and touchingly personal, preface by Arthur, written more than a three decades after the book first appeared, and it reprints the original 1950 edition (not the 1960 revision which was not carried out by Clarke). But the edition is rather poorly presented. One does need an inordinate amount of imagination to guess what parameters and units many diagrams have on their axes. The abundant illustrations - which range from historical photos from the dawn of rocketry to elaborate artistic visions of space stations and lunar explorations - are of barely acceptable quality, all black-and-white and with resolution worthy of a pretty hazy atmosphere. I do wish Berkley had done a better job with the printing of this gem, but let us be grateful for what we do have.
