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Restoring Earth: The Space Imperative

I’ve heard of Dyson spheres and Dyson swarms, but what exactly are Dyson ‘dots’? As coined by Greg Matloff, C Bangs and Les Johnson in their book Paradise Regained, the term refers to a type of solar sail. These sails are not meant for moving things around the Solar System, but for reducing the amount of solar radiation hitting the Earth. The authors imagine large numbers of the Dyson dots placed near the L1 point, using the momentum from solar photons to maintain their position. Imagine thousands — maybe millions — of these sails equipped with sensors to receive the instructions of their builders, communicate with each other, and make changes in the configuration of the swarm.

Could you use a sail array like this to cool off the planet? From the book:

…using reasonable middle values for the parasol parameters — 80 percent reflectivity or albedo, mass 53 grams per square meter, positioned 2,100,000 kilometers from Earth — we would need almost 700,000 km2 of sunshade area to achieve a reduction of 0.25 percent in the solar constant, that is, some 37 million metric tons.

And let’s put this into perspective:

…bear in mind that the United States alone burns about one billion tonnes of coal every year. One supertanker of the many hauling petroleum around the world’s oceans weighs about half a million tons fully loaded; and 37 megatonnes is roughly just 3 days’ supply of crude oil… If each Dyson dot has an area of 10 km2, then our array, or school, would consist of 70,000 units.

Now back into an even deeper perspective, which is what Paradise Regained is all about. The authors advise us to look to extraterrestrial resources, to mine the heavens as a way of reducing the industrial footprint on Earth and restoring the planet’s ecological balance. Think space for resources, then, and realize that the 37 million tonnes referred to above amounts to the mass of a single, small stony-iron asteroid some 300 meters across, which is a class of rock so small that we’re only now starting to look for them.

Paradise Regained is a bracing study of what we might do in the near future to make life better, and that includes asteroid missions that could help us protect the Earth via methods like ‘gravity tractors’ and solar ‘parasols’ as well as missions to exploit their resources. In this context, the word ‘exploitation’ has less bite than it does on Earth, for resources in the Solar System are vast, and exist in an environment so deadly that there is little humans can do to degrade it. Moreover, a small asteroid 1 kilometer in diameter might contain 2 billion tons of iron ore, enough to meet the annual global demand for one year.

The asteroid 16 Psyche may contain enough iron ore to take care of our needs for millions of years. Moreover, many asteroids contain nickel, cobalt, copper, platinum and gold. Thousands of Near-Earth Objects (NEOs) exist in the 100-meter range or bigger, providing an all but limitless pool of raw materials. Needless to say, the authors also throw into the mix the possibilities of tapping the Sun’s energy output — 3.86 X 1026 watts every second of every day. The infrastructure needs are huge, encompassing spacecraft, solar arrays, antennae, ground support equipment and more. Can we afford to build it?

…that all depends on the cost of energy and how much of a value we place on the environment. The cost of energy production is not as simple as dollars, euros or yen. What is the cost to the planet of the strip mining required for the coal we burn in our thousands of power plants? What is the payoff in reduced defense spending that will result from us not having to depend on the volatile Middle East for oil to generate electrical power? How much is it worth to eliminate the acid rain associated with the burning of fossil fuels? What benefits will we reap from a power system that produces no greenhouse gases? The authors contend that when the real societal costs are considered, as well as the real monetary cost from end to end, space-based solar power begins to look like a winner.

From mining to fusion, Paradise Regained covers the numerous options that space affords our species. As for the latter, helium-3 gets interesting because it’s a potential fusion fuel that, while rare on Earth, seems to be plentiful in the lunar regolith. If we can ever make fusion viable, a mixture of deuterium (heavy hydrogen) and helium-3 is a desirable fuel choice because it produces little residual radioactivity. Some estimates of helium-3 on the moon run to about a million tons, a potential solution to our energy needs for centuries.

Because it is stuffed with possibilities, it’s tempting to keep racing through this book popping out facts and prescient speculations, but I don’t want to ignore the moving, poetic side of it, reinforced by C Bangs’ lovely artwork, which harkens back to a pastoral world of the imagination even as it embeds itself in the cosmos. Thus the lovely Shakespeare quote from the introduction:

I know a bank where the wild thyme blows,
Where oxlips and the nodding violet grows;
Quite over-canopied with luscious woodbane,
With sweet musk-roses and with eglantine.

That’s from A Midsummer Night’s Dream, and it conjures up a vernal Earth we’d like to preserve even as we spread the benefits of technology and industry to the less advantaged. Myths of a ‘golden age’ are just that, reflecting a time-honored nostalgia for a past that never truly was, but there is a sense that we can ‘regain’ that dreamed of Earth by creating it for ourselves, using our technology wisely to offload industrial activities to nearby space. Buy two copies of this book and give one to your local school library. The ideas are spread out here in dazzling profusion, a chastening reminder to those who see no value in space exploration and believe such funds should be spent here on Earth. Here we learn that the space payoff may be huge, transforming our planet even as it feeds our dreams.


Comments on this entry are closed.

  • andy May 13, 2010, 8:59

    I’ve never liked the idea of these sunshades for “solving” the global warming problem. For a start, carbon dioxide dissolves in water to form carbonic acid, leading to lower oceanic pH which could have damaging effects on the plankton, therefore leading to a whole load of trouble in the oceanic ecosystem. Also it would still lead to changes in the way heat is transported around the planet even if the heat budget remained the same. Sunshades are merely a solution to a zeroth-order approximation of a much more complex issue, the devil is in the details.

  • John Hunt May 13, 2010, 9:38

    I think that this is a fundamental book. It pulls together the various concepts of how space development will help the environment on Earth. I wonder to what extent this perspective will begin to influence the discussion of how best to proceed to protecting and restoring the environment.

  • stephen May 13, 2010, 10:43

    We know of some stars such as Betelgeuse which might become supernovas at some point. I was thinking of using sunshades to block the light from those stars, just in case they go supernova. They could be accompanied by automated observatories which collect data from those and other stars. Is that too silly and impractical?
    I realize those stars might not go supernova any time soon.

  • Mark Meier May 13, 2010, 12:14

    Andy, I think another factor needs to be considered in this: if the Dyson Dots are solar panels, we can beam the energy to Earth, stop using coal and oil, and thereby reduce the carbon output of the planet. So the shade helps in the short run, the solar energy helps in the long run. Add to that the space infrastructure, and I think this would be a win-win-win. Even those who deny global warming would support an economoical way to get off coal and oil.

  • Chris T May 13, 2010, 13:30

    “restoring the planet’s ecological balance.”

    The Earth has never been in ecological balance. What, exactly, are we supposed to restore?

  • Tony Wheeler May 13, 2010, 13:41

    As a non-scientist that supports space exploration I usually struggle with the technical fine points discussed here, but today you have provided me with a source of information to persuade others that see no good reason to be in space.
    While there are other organizations that approach that issue more directly, please continue your work here with that in mind.
    Thank you.

  • Eric May 13, 2010, 14:16

    Like it our not, we’re all geo-engineers now, running a vast and uncontrolled set of tweaks of our atmosphere, oceans, and ecologies. I think this kind of discussion is invaluable, even though the proposed solutions may cause a cascade of different problems. Studying complex interactions including those that involve mitigation strategies is an obvious must.

    One of the points I appreciate most about this regards the role of space exploration and space science. Too many times I’ve heard people say that we should solve our problems on Earth before worrying about space. I think it’s more likely that we’ll never understand how to solve our problems on Earth without learning from space.

  • Matt May 13, 2010, 14:45

    If you’re going to put dozens of satelites in orbit like that, why not make them solar power sataleites in mid- or -deep orbit? It would be easier to get to than a LaGrangian point and it would largely remove the need for carbon-based fuels.

    I also think people are too focussed on asteroids when there are all the Near-Earth Objects that are little known, closer and largely uncataloged. I can imagine them being used as stepping stones to, say, Mars. You could probably plop an automated observatory on a few, too.

  • kurt9 May 13, 2010, 15:58

    I think asteroid mining will be limited to Platinum group metals. The other metals are too plentiful on Earth for asteroid mining to successfully compete. The rare Earth metals are not actually that rare and the largest reserves happen to be in the manufacturing country that has the largest demand for them: China. A successful mining operation would need to bring back only one 500-meter diameter asteroid every 10 years or so to meet the world’s supply of these elements, and could be entirely automated (no people in space).

    The solar shade idea is silly. If you are going to put solar shades in orbit, why not make them as solar power satellites and beam the energy back to Earth, just like the old L-5 scenario? The manufacture and deployment of these can be automated as well. Automation has progressed considerably since the L-5 society’s heyday of 1977 (e.g. “lights out” 300mm semiconductor fabs).

  • Steve Wilson May 13, 2010, 16:10

    Does the name “Dyson dots” mean that Freeman Dyson had anything to do with the concept?

  • steven rappolee May 13, 2010, 17:15

    I do not see why not the “dots” could pull double duty both as a power source and shade, this may be a bit far to transmit that power back to earth so there duty would be to smelt space based resources to build more of them self’s and other structures.
    reader Kurt forgets that launching all of this mass from earths surface completely nullifys that inexpensive iron ore from earth! better to both mine and smelt the stuff out there for use out there.

  • Eniac May 13, 2010, 20:39

    If you’re going to put dozens of satelites in orbit like that, why not make them solar power sataleites in mid- or -deep orbit? It would be easier to get to than a LaGrangian point and it would largely remove the need for carbon-based fuels.

    It is 70,000, not dozens. You are right that in Earth orbit they would work better. Because of their larger apparent size they would cover more of the sun. This would be partly, but not entirely, negated by the fact that they spend only part of the time actually shading the Earth. It would have to be LEO, though, to minimize the latter effect.

    However, those shades would not be 53 grams per square meter if they generated power, and it is MUCH cheaper to produce the same power by other means on Earth, even without carbon-based fuels. And, for the astronomers among us, would we really want so much shiny stuff in LEO?

    It does not help to push the idea of space travel with objectives that are more easily accomplished here on Earth. This applies to sunshades, space based solar power, Helium 3, and asteroid platinum alike. You can awe a few space-heads with it (preaching to the choir), but in the long run it is extremely counter-productive.

    There is no gold in them thar hills. Not for a long time. Exploration and tourism is where it is at, in the meantime.

  • Enzo May 13, 2010, 22:03

    Hi Chris,

    The Earth has never been in ecological balance but it has also very rarely been in a situation where species are lost so fast. The only similar situations in the past occurred at the Permian/Triassic boundary as well as Cretaceous/Tertiary boundary. After both episodes, the Earth was not a very nice place for a while. For a very long while when measured by human lifespan.

    Unfortunately, until exponential growth of the population continues, there is no way the situation can get anything but worse from that point of view. Any exponential growth of consumption destroys any advantage created by savings by efficiency very quickly.
    So, when it comes to carbon emissions or just about any form of consumption or pollution, I do not believe that there will be any reduction any time soon.
    Exponentials do not go on forever and the growth rate WILL go to zero. It’s a matter of us choosing the way it stops or let nature do it. I suspect that the latter will be rather unpleasant. It is also a matter of stopping it while you still like the place you live in.

  • Eniac May 14, 2010, 9:06

    So, when it comes to carbon emissions or just about any form of consumption or pollution, I do not believe that there will be any reduction any time soon.

    At least regarding pollution, there are quite a few examples in which there was reduction in the past. Have you seen images of Manhattan early last century? It was shrouded in smoke. In many industrialized regions, you couldn’t hang out the laundry to dry without it getting gray with soot. What happened to smog alarms? Did you know our rivers are mostly fit for swimming again, after a long time of being filthy dumps for sewage and industrial waste?

    Unfortunately, until exponential growth of the population continues, there is no way the situation can get anything but worse from that point of view.

    I assume you mean “until growth stops”. Two things: 1) As noted above, quite a few things have gotten better while growth continued, and 2) Population growth has already stopped in the most developed countries, and every indication is that this trend is going to continue until we hear cries of “Underpopulation!” and “The human race is dying out!”.

  • Chris T May 14, 2010, 15:51

    I was objecting to the sloppy language. ‘Ecological balance’ suggests that there is a natural state the Earth ‘should’ be in and casts humans as an aberration. Because there is no and has never been such a balance it obfuscates the real debate: what are the conditions that we, as a species, want or can tolerate? What are we willing to sacrifice to get there? Tossing about moral arguments as though they describe empirical reality results in an unnecessarily constrained discussion and risks creating much worse outcomes.

    As eniac has already noted, population growth is slowing and projected to hit zero in 2050. In regards to pollution, the first world’s air and water is probably the cleanest now that it has been in the last two hundred years. It is only rich populations that can really afford to take care of their environment.

  • C Bangs May 17, 2010, 10:40

    I’m delighted with this dialog! Some of the concerns are covered in “Paradise”. For a YouTube summary our link is

  • Stevo Darkly May 18, 2010, 0:54

    You know, the problem with making the sunshades double as solar power collectors, as some suggest, is that you would be lessening (or destroying) their effectiveness as sunshades. Because instead of blocking solar energy from reaching the Earth, they would be gathering it up and beaming it to the ground. And sooner or later that energy would manifest itself as heat. So you end up adding to the Earth’s heat balance, perhaps more than you are reducing it.

    So if you use the sunshades, use them as sunshades only.

    Am I mistaken?

  • Geoff May 21, 2010, 0:52

    The idea of exploiting space resources has never made any sense to me. Think about it: you can process asteroidal iron in-situ and ship the finished product back to Earth, but melting down scrap steel is still too hard?

    The basic problem is that an Earthbound civilization capable of mining the moon or asteroids wouldn’t need to – it would have all the technology needed to get its basic materials from sources closer to hand. At a minimum, those materials are (by definition) available in the civilization’s own waste stream – and a spacefaring civilization must necessarily be very, very good at recycling.

    Or consider the ecological perspective. Protecting the environment requires more than just not taking resources from it – you also have to refrain from dumping wastes into it. So where do the waste materials go? Are they shipped off-planet (back to the asteroid belt, perhaps)? I like a good technology story, none better, but I struggle to suspend disbelief at this point.

  • Ronald May 23, 2010, 3:06

    I agree with Geoff: beyond a few very precious (energy intensive) materials such as He-3, it seems to make (very) little sense to exploit space resources (such as asteroids) for utilization on earth, since it will nearly always be much cheaper to exploit those or substitute resources here on earth.
    Exploitation of those resources for utilization in local space is an entirely different matter, of course.

  • NSSMemphis May 27, 2010, 18:26

    Save the Earth Leave! That is, not necessarily you and not necessarily today but as permanent species survival and development strategy. Humanity, cannot exist on this planet and create the kind of prosperous civilization most of us want and aspire to without eventually facing resource shortages and ecological failures. The one answer, that will ultimately preserve our hope and dreams for an unlimited, prosperous future and as much as possible of this amazing bio-sphere is to start moving as much energy production, resource acquisition and population of the planet as possible as fast as reasonable.

    Perhaps, starting with one of the greenest forms of energy capable of powering our civilization, solar power satellites. Two are on order now. They offer the best hope to provide unlimited power 24/7 anywhere on earth without destroying mountains, damning rivers, or generating huge mounds of radioactive waste. Remember, at least, half of the planet does not have access to electricity now.

    In public events, this statement has almost always been effective in generating a positive discussion and convincing people on the left and right to become enthusiastic about space and space development.