The Boundless Adventure

Below is the Keynote Lecture that I gave recently at the 2005 annual meeting of the Foundation for the Future (www.futurefoundation.org), held at Bellevue, Washington.

Iwould like to make clear that I am not a scientist, nor do I have a scientific degree. I am a science journalist, and I've done nothing but write about science and report science news for the last 35 years. So I hope that what I'm going to say won't sound too obvious and elementary. However, since I'm going to talk about the future of space travel, there's one boast I'd like to make. I was in the press room in Houston in 1969 when Neil Armstrong stepped on to the Moon.
Perhaps the most interesting question about space travel in the coming millennium is who, if anyone, is going to be in charge of it. People tend to assume that this will be some government body such as NASA, or some intergovernmental agency such as the so‑called "World Space Council'' that appears in some science fiction novels, or perhaps, as in the "Alien'' films, some all powerful private organisation known as "The Company.'' Indeed, until very recently, some very senior officials at NASA have been convinced that they will always be in charge, not only bearing general responsibility but in planning every step. As one of them put it 14 years ago: "Space technology progresses like a staircase with steps and landings. On each landing, we pause to look back and forward, re‑assessing where we are, catching our breath, and then begin the assault on the next plateau. This is exactly how human progress is going to work in space, quite as on Earth.'' If it is permissible for a foreigner to criticise America's space agency, I must say that this sounds rather doubtful. I don't think this is how human progress is going to work in space, and I don't think it has ever worked like this on Earth. Indeed, when one looks back at the unpredictably rapid bursts of technical advances, one gets the impression that this scenario is extremely unlikely. And since NASA and other government space agencies tend to act rather slowly, it cannot be more than a matter of decades before private industry outstrips them. Already we see the beginnings of this with the winning of the X-Prize by a private company sending a manned craft to the edge of space, and the ambitions of several companies to offer space tourism. And perhaps in less than a century after that, events in space will be beyond the control of any government. In the coming centuries, driven by technology and profit, people will expand into space in many different ways. I have no doubt that people and cargo will routinely be lifted into Earth orbit by elevator. Some people will be building settlements on the Moon and Mars, and on the moons of Jupiter and Saturn. Others will be intent on building starships. I'm not going to talk about these projects - I'm sure other speakers will - but of an equally interesting long-term and vast enterprise, building commercial empires among the asteroids. There are tremendous possibilities for wealth in the main Asteroid Belt, between the orbits of Mars and Jupiter. There exist on these million or more small worlds all the essential substances to construct countless prosperous settlements. They are, after all, filled with substances of incomparable commercial value. Colonising them will be the work of countless generations. The asteroids, or minor planets, are known now to exist in enormous numbers, particularly in the main Asteroid Belt. A few hundred others pass close to Earth, causing great concern since one day one or more of them is certain to collide with us. But I am speaking of the main belt beyond Mars. A recent survey by the European Space Agency's Infrared Space Observatory estimated the number of them more than a kilometre in length at between 1.1 and 1.9 million. And some of them are very big, far bigger than a mere one kilometre across. If these orbited a planet they would be called sizeable moons. Here is a table of those with diameters greater than 200 kilometres:   Asteroid Diameter (km) Ceres 918 Pallas 522 Vesta 500 Hygeia 430 Davida 336 Interamnia 334 Europa 312 Eunomia 272 Euphrosyne 248 Cybele 246 Juno 244 Amphitrite 240 Camilla 236 Doris 226 Iris 204 Source: Corporation for Atmospheric Research, University of Michigan
Here also is a picture of Ceres, the largest one. Note that it is almost spherical, quite unlike the potato-shaped appearance of smaller asteroids, things like flying mountains. When an object is more that about 200 kilometres in diameter, its gravity forces it to assume a spherical shape:
Until the last century, asteroids were of little interest to anybody. The 19th century German astronomer Ernst Klinkerfues spoke for many of his colleagues when he called them the "vermin of the skies'' because their images crept like worms across his photographic plates of the stars. Later, it was imagined that the Asteroid Belt was so densely packed that any spacecraft venturing beyond the orbit of Mars would be bound to crash into one of them. But in fact, although they are so numerous, such an encounter would be extremely unlikely. This fact illustrates what, on the human scale, is the almost unimaginable vastness of the solar system. Christopher Columbus, surveying the wealth of the Americas, prophesied: "Where there such lands, there should be profitable things without number.'' The same will apply in future centuries to the asteroids. Robert Zubrin has called this region the "Persian Gulf of space'', but I think this may be an understatement because the Persian Gulf is only abundant in one commodity. Also, the wealth of the asteroids should eventually exceed by many million-fold the riches of Earth. In predicting that we will exploit them I am not saying anything new. We have been doing so for nearly 3,000 years. It was the Hittites, that strong-willed people from Syria who waged successful war against the Pharaohs, who first began to fashion their swords from meteoritic iron, smelting it with coke to make it more durable. This began the Iron Age, and was one of man's most important accomplishments. The Trojan War, which took place about 300 years before this happened, lasted a full 10 years because it was fought with bronze weapons and bronze armour. The recent movie "Troy'' didn't entirely make this clear. Rudyard Kipling commemorated the coming of the Iron Age with the verse: Gold is for the mistress - silver for the maid -  Copper for the craftsman cunning at his trade. "Good!'' said the Baron, sitting in his hall, "But Iron - Cold Iron - is master of them all.'' The asteroids are rich not only in iron but in many precious metals. For example, radar observations of the asteroid 1986 DA, which is little more than a kilometre in diameter, have revealed that its metal content is worth about $110 billion. It contains 100,000 tons of platinum, worth about $800 per ounce at today's prices. It also holds about 1,000 million tons of nickel, valued today at about $14,000 per ton in its pure form, and about $100 billion worth of gold. These prices of course fluctuate enormously, but they do give force to the 1990 Augustine report to the White House on the long-term future of the US space programme that asteroids will eventually have to be mined as metals become scarce on Earth. Platinum, for example, is particularly prized because it removes environmentally-harmful gases from car exhausts in catalytic converters, devices that are gradually becoming compulsory in many countries. And I'm not only thinking about replenishing the resources of Earth. This will be only a sideline in the long-term future. These metals will be of important use in space itself–metals that can be found up there and used up there. Space travel today is far more expensive than it needs to be. One of the many reasons that the space shuttles are so tremendously costly to operate is that everything their astronauts need–all their food and water, all their air, all their fuel–they must take up from the ground. At present it still costs about $10,000 to put half a kilogram of cargo into Earth orbit. A shuttle mission still costs upwards of $500 million. Yet these vehicles are like islands of scarcity in a vast ocean of plenty. Our descendants will regard this way of conducting space operations as insane. For how much cheaper such expeditions would be if the raw materials for food, water, air, fuel, and machine tools could be taken from space itself! The price of travelling in space and living in space could be reduced by more than a hundredfold. This is the true promise of the asteroids, one that reduces to economic insignificance the prospect of using them to restock the Earth.
As for metals, wherever people travel and settle there will be huge demand for them. Nickel, a malleable metal with a high melting point, does not tarnish and is therefore much used in alloys and electroplating. Gold plate, because of its chemical stability, will be essential to protect machinery in corrosive atmospheres. Mars, when we get there, we will find has a very corrosive atmosphere because of its monatomic oxygen. And above all, gold covering will be needed to protect spacecraft from solar radiation, to prevent it from becoming overheated. Remember the gold foil covering which was used to protect the Apollo landers:
And there are many substances out there that will be of far more value to spacefarers even than precious metals. The most important of these is water. Without water life is inconceivable, and with it life of almost any kind can be imagined. There is nearly 200 times more water in the form of ice in the solar system than there is in all the oceans, lakes, rivers, ice sheets and glaciers of Earth. It can be used not only for drinking but for cleaning, diluting, for breaking down substances and as a radiation shield against dangerous cosmic rays. Frozen as blocks of ice, water can be transported and stored in huge quantities without containers. Of the asteroids in the main belt, a huge number of these are "carbonaceous' - containing compounds of carbon. These also contain "volatile'' elements, such as hydrogen, oxygen, sulphur and nitrogen, so called because they can be changed from solid to liquid to gas and back again. Yes, the most valuable materials are those that are commonplace on Earth, but expensive to bring into space. The solar system has them all in plenty. Consider this short list: Hydrogen, methane and methyl alcohol for fuel. Nitrogen for air and agriculture. Carbon monoxide and sulphuric acid for metallurgy. Oxygen for air and for oxidising fuel. Hydrogen peroxide is also a good oxidiser. Carbon dioxide, hydrogen sulphide, nickel carbonyl, iron carbonyl, ammonium hydroxide and ammonia for agriculture. Sulphur dioxide as a refrigerant. Sulphur trioxide for making sulphuric acid. I've made this into a slide, with freezing and boiling points added:
Substance Boiling point (°C) Freezing point (°C) Uses Hydrogen –259 –253 Fuel Nitrogen –210 –196 Air, agriculture Carbon monoxide –199 –192 Metallurgy Oxygen –218 –183 Propellant, air Methane –182 –164 Fuel Carbon dioxide –57 –78 Agriculture Hydrogen sulphide –85 –60 Metallurgy Ammonia –78 –33 Agriculture Sulphur dioxide –73 –10 Refrigerant Nickel carbonyl –25 +43 Metallurgy Sulphur trioxide +17 +45 Making sulphuric Methyl alcohol –94 +65 Fuel Ammonium hydroxide –77 +100 Agriculture Water 0 +100 Life support Iron carbonyl –21 +103 Metallurgy Hydrogen peroxide 0 +150 Oxidiser Sulphuric acid +10 +290 Metallurgy
Source: Charles R. Nichols, "Volatile Products from Carbonaceous Asteroids’’, contribution to Resources of Near-Earth Space, edited by M.L. Guerrieri, J.S. Lewis and M.S. Matthews (University of Arizona Press, Tucson, 1993.)
As for energy, without which industrial production is impossible, I am gambling that a great deal can be done with deuterium from hydrogen, and used to build nuclear fusion stations. An even more advanced technology would be pure proton fusion, assuring a virtually unlimited supply of energy using simple hydrogen. We haven't yet worked out how to do this, but the stars have - they do it the whole time. Out in the main Asteroid Belt, it won't be cold and dark. It won't be like living on Pluto or in the far-off Oort Cloud of comets.
The Sun will still be very bright. From Ceres, for example, the largest asteroid, the apparent magnitude of the Sun is about  - 26 while from Earth it is - 28. From the Asteroid Belt you'll certainly need dark glasses to look at the Sun. Just to put this in perspective, the apparent brightness of Sirius, the brightest star in the night sky, is only - 1.5. So the Sun as seen from the Asteroid Belt is about 10 billion times brighter than Sirius. But warmth is just as important as light, and I have no doubt that warmth can be achieved with very large mirrors to concentrate sunlight. Here is a picture of a proposed mirror that would increase warmth on Mars:
No doubt some of you are thinking that all this sounds much too easy and optimistic. I'm sure you're probably right, and that there will be many failed ventures. Charles R. Nichols, an industrial chemist at the Bose Corporation at Framingham, Massachusetts (to whom I owe the above list of useful substances), gave this warning a few years ago: "Before any such large-scale engineering project can begin, it must receive financial approval. Investors require proof that the project is a good investment, and part of the proof is a comprehensive plan for minimising risk. Accountants must be pessimistic precisely because engineers cannot help being optimistic. Every new technology has unforeseen bugs that need to be worked out. A project that relies too heavily on new technology will limp through life and die in shame.'' The word "investors'' here is very well chosen. No government or official space agency is ever going to do the things that I have been describing. They are just not what governments do. Governments seldom think ahead for more than about five years - their period in office - and these are the projects of decades or even centuries. And most of what takes place among the asteroids will be done not for science but for profit. The outer solar system is no place for bureaucrats; the capitalist will be its king. But one word of caution. I've been talking about the Main Asteroid Belt beyond the orbit of Mars. Many people will be wondering: Why go that far? Are there not several hundred near-Earth asteroids, filled with all the useful substances I have described, which are much easier to get to? The answer is that, except for purely experimental work, it's not a good idea to exploit them as a long-term project. The reason is political! Extensive work on them will be regarded on Earth as being too dangerous. Left to themselves, one or more of them is certain eventually to crash into Earth. And how much more dangerous they will seem if they appear to be in the hands of some billionaire who might change one of their orbits carelessly, putting it on collision course with Earth! The feeling will arise on Earth that this is an enterprise that ought to stopped, if necessary by military action. However, on the comparatively far-off main Asteroid Belt, there should be no such fears. The sheer difficulty, governed by Isaac Newton's First Law, of moving a large body towards the Earth from so great a distance, will make any such danger seem negligible.
I've been describing some tremendously complex tasks. Some people might imagine that they can be carried out by robots and managed from Earth. But this a myth. Robots will always of course be an essential tool, but to expect them, by themselves, to establish a commercial civilisation in space must be regarded as absurd. With all respect to HAL in 2001: A Space Odyssey, I believe that machines will never be able to handle unexpected situations. They will only be able to do what they have been programmed to do. Tasks in space beyond a certain complexity are for astronauts only. Here is a slide that illustrates this idea, which describes a position in chess that demonstrates the weakness of so-called "hard'' artificial intelligence:
White, in this position, is heavily outnumbered. He has no officers while Black has three. On the other hand, White's King is protected by an impenetrable array of pawns. White can easily force a stalemate by moving his King back and forth along the back rows. But a computer will never see it this way. In a famous experiment, when this position had been set up, the all-powerful chess-playing machine Deep Thought (that once defeated Kasparov) made the incredibly stupid mistake of taking the Rook with his pawn! This exposed Deep Thought's pawns to attack by Black's remaining Rook, and he soon lost the game. I don't know of any chess-playing program, in this situation, that will not make the same mistake. In the words of Professor Roger Penrose, in his book Shadows of the Mind: "The human player sees the barrier of pawns and understands that it is impenetrable. The computer did not have that understanding - it simply computed move after move. That is the difference between mere computation and the quality of understanding.'' In an earlier slide I mentioned agriculture. There is nothing to prevent people for starting agriculture in the outer solar system, and living as we live, on worlds that are currently airless and barren. One of the greatest thinkers in the last century was the late Gerard O'Neill, a professor of physics at Princeton. I wonder how many people here are aware of his work or have read his 1977 book The High Frontier: Human Colonies in Space? (SLIDE c:\wpdocs\O'Neill's book.doc) It is largely forgotten today, but I believe it will be very well known in coming centuries.
He worked out, in great engineering detail, how people could live on the inside of hollowed-out asteroids. A larger asteroid could be a home for hundreds of thousands of people! Imagine a metal cylinder perhaps 40 kilometres long and 10 kilometres wide. Its interior surface would be a "world'' of 1,400 square kilometres, three times bigger than the area of our biggest cities. The only difference from a natural planet would be that their horizon would curve upwards instead of downwards. One can imagine that on a clear day - because there would be a nitrogen-oxygen atmosphere inside - people would be able to look up and see the roofs of their neighbours facing down towards them! Inside would be a landscape of towns and farms, meadows, vineyards and factories.
There might ultimately be tens of thousands of these artificial worlds, perhaps many more, moving wherever their inhabitants wished. This may sound fantastic. Yet many of the things we routinely do today would sound equally fantastic to someone in the 18th century. Or, as Arthur C. Clarke put as long ago as 1951: ``If we have learned one thing from the history of invention and discovery, it is that, in the long run–and often in the short one–the most daring prophecies seem laughably conservative.'' I knew O'Neill. He was a friend of mine. Shortly after his book was published, I was in his study in Princeton. His fame at that time was enormous. He was constantly being invited to appear on television. His table was covered with laudatory reviews, and several popular books were being written about him. His work was given unstinting praise by Isaac Asimov and Carl Sagan. Yet he was not happy. He was impatient. He could not understand why no moves were being made to put his ideas into execution, why nobody was not yet even making the preparatory steps to construct an O'Neill habitat in space. I didn't understand this myself at the time, but I think I do now. History takes a long time to happen, but happen it surely will. To quote Arthur C. Clarke again: "At the present rate of progress, it is almost impossible to imagine any technical feat that cannot be achieved - if it can be achieved at all - within the next few hundred years.'' Wherever people live in the solar system beyond Earth, their gravity will be weaker. (One could of course try to live on the surface of Jupiter, if there is one, where people would weigh 23 times more than they weigh here, but I wouldn't recommend it.) On the Moon people would weigh one sixth what we weigh here, on Mars about a third, and on many of the asteroids a little as a thousandth. On a smaller one one would need to anchor oneself to the ground to avoid flying off into space. My point is that hardly anyone, having lived for any time in space, would ever want to live again on Earth. Our gravity would be torture. It might even kill them. And indeed they would feel no need ever to revisit Earth. They would be space people for ever. In the words of the science writer Fred Golden, a supporter of O'Neill's ideas: "As the space people become more adept at living in their new worlds, they would become less and less dependent on Earth. Many of them might not even bother to return to their home planet for visits: for younger people born in space, Earth might only be a place that they had heard about from their parents or read about in the colony's library or seen on a video screen. It might eventually be regarded as just another planet.'' To this I would add that there will be a degree of political freedom - that is to say the right to migrate to wherever you please - that mankind has not fully experienced since the middle of the 19th century. Earth is becoming an increasingly restricted place to live. Wherever we are, we face countless taxes and regulations. Moreover there is a trend on Earth towards world government, and in the long run world government can easily turn into world dictatorship. But out there, there need be no such fear. For space is a sea without end. I don't think any asteroid-dweller will ever hear the song "Don't Fence Me In.'' At the burn of a rocket, one can wander off somewhere else, migrating ever further into the outer solar system and planting new colonies, eventually even passing Neptune and Pluto. Once proton fusion technology has been perfected, the cold and the dark will cease to be enemies, for miniature artificial suns can be constructed wherever they are needed. There may be local government but no central government. Nobody on Earth on anywhere else will be able to exercise control over this scattered off-world population because you can't make people pay income tax if you don't know where they live. I know of one interesting example in history where this actually happened - where a government wanted to arrest some people who had fled to an island, but they couldn't carry out the arrests because they couldn't find the island! They knew its name, but when they came to look for it, it wasn't there. This was Pitcairn Island in the Pacific. In 1790 the mutineers of the Bounty took refuge there, and the revengeful British Navy sought it in vain. It hadn't moved - like an inhabited asteroid - but it had been inaccurately placed on Admiralty charts. Out in space, this drama will recur countless times. On the other hand, an absence of central government may have its dark side. It could certainly lead to the kind of unrestrained corporate ruthlessness shown by the "Rock Rats'' in the brilliant novels about life among the asteroids by Ben Bova. And it might go further, into piracy. I take the liberty of going back to history again. The following passage is by Sir Arthur Conan Doyle, of Sherlock Holmes fame, in a short story about piracy in the Caribbean: "When the great wars of the Spanish Succession had been brought to an end by the Treaty of Utrecht [in 1713], the vast number of privateers who had been fitted out by the contending parties found their occupation gone. Some took to the more peaceful but less lucrative ways of ordinary commerce, others were absorbed into the fishing fleets, and a few of the more reckless hoisted the Jolly Roger at the mizzen and the bloody flag at the main, declaring a private war upon their own account against the whole human race. "With mixed crews, recruited from every nation, they scoured the seas, disappearing occasionally to careen in some lonely inlet, or putting in for a debauch at some outlying port, where they dazzled the inhabitants by their lavishness and horrified them by their brutalities. On the Coromandel Coast, at Madagascar, in the African waters, and above all in the West Indian and American seas, the pirates were a constant menace. With an insolent luxury they would regulate their depredations by the comfort of the seasons, harrying New England in the summer and dropping south again to the tropical islands in the winter. "They were the more to be dreaded because they had none of that discipline and restraint which made their predecessors, the Buccaneers, both formidable and respected. These Ishmaels of the sea rendered an account to no man, and treated their prisoners according to the drunken whim of the moment. "Flashes of grotesque generosity alternated with longer stretches of inconceivable ferocity, and the skipper who fell into their hands might find himself dismissed with his cargo, after serving as boon companion in some hideous debauch, or might sit at his cabin table with his own nose and his lips served up with pepper and salt in front of him. It took a stout seaman in those days to ply his calling in the Caribbean Gulf.'' But despite all these hazards, I believe that population out there will multiply. Here on Earth, population is a subject we all worry about, perhaps needlessly. With all the substances necessary for life and manufacture, how many people will be able to live in the solar system beyond Earth? Contrary to what many people suppose, human population does not rise continuously but by logarithmic jumps that depend on the physical environment. The first such jump occurred a million years ago when Homo sapiens became a toolmaker and tool user; when human numbers rose to about five million. The next was about 8,000 years ago after the last Ice Age ended, with the coming of cities and eventual empires, which increased the population to between 50 and 140 million. The third surge occurred about 300 years ago with the coming of the scientific and industrial age which fairly quickly raised numbers to the scale of billions. The fourth great increase will come as we conquer the solar system, and this increase will be greater than all the others. How much greater, one cannot tell. But by the availability of water in the solar system, within a thousand years or so we could be looking at a population of 1,200 billion, 200 times the present population of Earth. This figure of 200 is of course absolutely nothing to the number of people who will eventually be living on the planets of other stars. But it does show us what can happen even in our own solar system, before we have travelled a single light-year. As Mr Golden says, in the distant future there won't be anything very special about Earth.