Why Mars?

Its very common for people who are unfamiliar with the arguments for space colonisation to suggest that its ridiculous on the face of it that humans can move to Mars and live there. They typically cite the fact that there are no permanent residents in Antarctica as proof of this.

Here is a good recent example of the argument, from an international affairs columnist.

The CEO in question is obviously Elon Musk and this refers to his intention to establish a city on Mars. This tweet is presented as if its an irrefutable knock-down argument. The rather condescending tone of it, as if this were the most obvious thing in the world and space advocates were simply dumb for not having thought of it, is a hazard when you don’t bother to check if there is already a response to your argument before you publicise it. I don’t mean to pick on this one person – but his argument is so very common it is worth having a rebuttal to hand.

There are many good personal reasons to go to Mars – exploration, adventure, the opportunity to start a new branch of human civilisation – but that isn’t really the question at hand here. What I think it boils down to is why building a Mars settlement is rational (or not) from a civilisational perspective. It very much is, and I can explain why.

Antarctica is Poor

The Earth presents to Sun a surface of 128 million square kilometres, allowing it to capture 174 million gigawatts of energy continuously. We harvest a significant portion of this – about 30% of the ice free land area of the planet – through agriculture in order to drive our civilisation. We collect some through solar power, recover ancient solar energy through fossil fuels, and harness winds driven by the Sun’s power. Three forms of energy not directly dependent on the Sun – geothermal, nuclear and tidal – are very marginal in comparison to agriculture. We are to a good approximation a solar power civilisation.

Antarctica is incredibly poor in solar energy. The Antarctic Circle fairly approximates the continent of Antarctica, and the surface area the Antarctic circle presents to Sun at equinox 1.8 million square km, less than 2% of the total cross section area of Earth. At the southern summer solstice that briefly rises to around 6%, whereas at the winter solstice it receives no direct sunlight at all. The equinox approximation is good enough as a time averaged value for this calculation though.

The Earth as seen from the Sun at equinox, with the Antarctic Circle marked

Solar flux at Earth’s average orbital distance is 1.36 gigawatts per square kilometre, whereas at Mars it is only 0.59 GW/km2, with Mars varying more than Earth due to the eccentricity of the planet’s orbit. Even taking this lower insolation into account, Mars gathers about 10 times as much energy as Antarctica, and crucially for most of the planet the intermittency of this energy isn’t nearly so bad. As on Earth, at most latitudes the night lasts hours rather than the months of darkness experienced in Antarctica.

Mars captures about 12% the energy of Earth – or about 40% of the energy of Earth’s land area. This would represent a significant boost to our potential civilisational capacity, even though we would not use it all. It might be tempting to think that unused areas of Earth besides Antarctica might provide a similar energy harvest, but the problem there is with the notion of what is really unused.

Seasteading may allow more energy capture without leaving Earth – but it suffers from a lack of raw materials besides those found in seawater, and its questionable how much independence such settlements would really have. Such independence they do have may legitimately be questioned if seasteaders start to have an impact on the marine environment – because the energy that falls on the sea is already in use, by the biosphere, and much of the Earth’s population think that is the best use for it.

Sometimes the Sahara or Gobi deserts are cited as alternative locations. These deserts are all in existing countries, and therefore not really subject to new human settlement without either submitting to the authority of these countries or fighting them. Also, like the sea, these places are ecosystems and not blank slates that the rest of humanity will automatically be happy with settlers exploiting.

In one respect, we are already a Kardashev type I civilisation – one that uses all the energy available to a planet – because we place nonzero value on the natural environment and thus, to a less or greater extent, use every photon of sunlight that falls upon the Earth to support it – and because when we do not divert this energy to industrial purposes it is purely by our choice and has been so since the mid 20th century, when all of the surface of the planet became reachable.

Mars and Beyond


I can thus summarise what the unique appeal of Mars is, from a dispassionate economic perspective:

Mars offers lots of unused energy impinging on raw materials we can easily use, at a location where accessing more energy is much easier.

This latter part is important because Mars is not the final destination. Thinking in terms of energy capture as I do leads to an O’Neillian conclusion that humanity should ultimately live in free floating habitats. The total surface area of solid bodies in the solar system is just too small if we want to really start exploiting our home star. However, in the near term, we need to live near the resources that we require. The industrial revolution started near the coal supplies for a good reason, and the costs of transporting raw materials must figure into our plans for space settlement. Our current technology, more or less, will let us work with the materials present on Mars to continually expand our presence there, and problems such as gravity and radiation shielding are easier to solver on a planetary surface.

Once a branch of human civilisation is established on Mars, it can much more easily access the remaining energy of the solar system – the escape velocity of Mars if only 5km/s compared to 11.2km/s for Earth. Placing our industry in a shallower gravity well thus has substantial material benefits that cannot be found anywhere on Earth.

Looking at Mars this way also explains why other colonisation targets should not be as high priority – Ceres has an even lower escape velocity than Mars, but is far from the Sun and small so is energy poor. Venus gathers more energy than even Earth, but the part we could possibly inhabit, the tops of the clouds at 50km altitude, lack many resources and the escape velocity is almost as high as Earth’s, never mind the extra velocity required to then get out of the deeper part of the Sun’s gravity well. Our Moon has a low escape velocity and captures a fair amount of energy – but the two week nights for most of its surface make it challenging to exploit, and it seems to be short of some key volatile elements. For that killer combination of energy, raw materials, and ease of access – Mars is the place.

This shows Mars is a promising prospect for expanding our energy capture and material resources. There are some making the case that this in itself is a bad thing – but if people are making such a case they should do so openly, and admit what it really means for human wellbeing, rather than throwing around cavils about Antarctica.

For the rest of us, who wish to see humanity continue forward, improve our material well-being and accomplish ever greater technological feats, there is no reason to wait, and certainly no net benefit in carving settlements out of the remaining wildernesses of Earth. The sunlight that does not strike the Earth outweighs the sunlight that does strike it by a factor of 2 billion, so even if we ultimately could not capture more than 0.1% of this, it would still support a population of 16 trillion humans with a per capita energy consumption (including supporting biospheres) 1000 times greater than we currently have. The smallness of current terrestrial civilisation compare to a potential solar civilisation means that this planet will ultimately diminish in significance, and all of its history will be a mere prologue to the larger history of humanity. The day when we establish our first settlement on Mars will be the beginning of Chapter One.


The Environmental Politics of Space Settlement

I am an advocate for the near-term human settlement of space. I am also an environmentalist. I was formerly a member of the Green Party of England and Wales, and stood as their parliamentary candidate for Leicester West in the 2015 election, scoring that parties highest ever vote there.

I accept the scientific consensus on anthropogenic climate change, and believe it is necessary for governments to take swift action. I am pro-nuclear – but that is not the reason I am no longer in the Green Party; quite a few people there are even though the leadership won’t admit it. I left as I thought the internal structures of the Party made it ineffective, and in any case its primary concern has now been adopted by every significant party in this country. This is an issue with many Green parties across the democratic world; the mainstreaming of the climate issue has left them without their main unique selling point, and they tend to default to being a protest party and/or just a woker version of their countries social democratic party. Regardless, I remain committed to supporting the decarbonisation of our economy and would not support or vote for a political party that does not.

I mention this, because in some corners, space settlement and protection of the terrestrial environment are portrayed as being in conflict. This is largely a one-way thing; no space advocate wants to see Earth’s biosphere damaged, but many environmentalists want to shut down (or at least restrict) human space settlement. There is tied up with this a fear that rich people will use a space colony as some kind of escape plan, shrugging off their social responsibilities and especially their environmental ones. The narrative as stated in this article is that, having fouled up this planet, billionaires will simply skip to the next one and leave the rest of us to clear up the mess.

One person who has taken this position is Carolyn Porco, a scientist who formerly worked on the Cassini mission for NASA. She has a recent TED talk on the issue which ends with a plea for Jeff Bezos and Elon Musk to abandon their efforts at putting humans into space and instead turn their wealth and efforts towards saving the Earth. Perhaps it is reasonable to direct such a charge at Bezos, but is she unaware of Musks other business interests?

I’m going to skip discussing Porco’s anti-capitalism for now; although this far from uncommon from people who take this position. There is plenty to discuss there – the worrying tendency in the last decade or so of the left to oppose spaceflight. I’ve covered this before, but here want to focus specifically on environmental matters.

The Carbon Cost

First I would like to address the direct environmental impact of SpaceX launches; at present the number of rockets they launch is not large enough to really make a difference on a global scale, but it still raises concerns in some quarters and if SpaceX massively increases their flight rate it is worth considering.

According to the SpaceX website, Each Starship/Superheavy vehicle contains 4600 tonnes of methalox propellant. I’ve created a spreadsheet, assuming perfect stoichiometric ratio of methane/oxygen, 50 passengers and 6 tankers per Starship to Mars and 500 per Starship to LEO, and then worked out the CO2 produced per flight. Taking per capita CO2 emissions from Our World In Data I have then worked out how long it would take to produce the same amount of CO2 just by day-to-day activity.

The CO2 emission data is averaged over very unequal populations, so is likely a substantial underestimate for the kinds of people who can afford to fly to space in the near future. Even so, it shows that removing wealthy westerners from the biosphere permanently is carbon negative if done at a reasonably young age. There may be still carbon emissions from launch cargo to Mars that they will use; but to get to a point where flights to Mars are regular enough for their CO2 emissions to be an issue then any settlements there will have to be fairly self sufficient. Very few people are rich enough to make a life for themselves on Mars using mostly imported goods.

There is the issue of water vapour produced by methane combustion; the contribution of this to the greenhouse effect is considered minimal at sea level, as it precipitates out, but at altitude the picture is more complex, and truthfully I don’t understand the latest research on this. However, even if water vapour had as much impact again as the CO2 emission then the conclusion would be similar.

The carbon emitted by a trip just to LEO is only a few months of normal emission in the West. At some future stage of space development, I expect both propellant for interplanetary transit and the cabins and supplies will be sourced from other celestial bodies, and thus a trip anywhere in the solar system will only have the impact of the Earth’s biosphere of a single passenger launch. If this could be done for trips to Mars, the carbon emissions of launch would be offset by your absence before you reached the planet.

This seems to get rockets off the hook for carbon emissions – and in any case, SpaceX intends to make them entirely carbon neutral by making methane through carbon capture – but it doesn’t mean that the environment can be saved, or seriously impacted in a positive way, by removing people from the planet. There are just far too many people. Musk is considered optimistic wanting a city of a million people on Mars, and removing a million people’s carbon emissions would do essentially nothing to arrest climate change. In the long run, the idea, touted by Jeff Bezos, of removing as much human activity from Earth as possible to preserve it is probably sound – be even he made it clear this is a multi-generational effort, for which he can only hope to lay the groundwork in his lifetime. Climate change is a problem right now, and as shown above it is orthogonal to rocketry.


The idea that rich people want to exit a dying planet is essentially expressing a problem of incentives. People like Carolyn Porco want to make sure that billionaires continue to be dependent on the same biosphere as the rest of us and so are sufficiently motivated to manage it correctly.

There are a few problems with this view. First is the idea that space settlement is for the rich only – if it is, it won’t work. The motivation for radically lowering the cost of space access, which SpaceX is doing right now and others such as Blue Origin hope to do in the future, is to open up access for a much larger portion of humanity than can presently go. They need to do this to create a market for space services large enough for their goals to be funded.

Secondly, the idea that rich people can fix climate change (or any other significant issue) is nonsense. The presumption that they can is based on the observation that they have a lot of money – but compared to governments, they really do not. Jeff Bezos is currently the richest man in the world. It varies with the price of Amazon shares, but his net worth is just shy of $200 billion. For comparison, the US Federal budget is over $4 trillion – per year. The Department of Defence alone has a $700bn/year budget, so a total liquidation of Mr Bezos would keep the lights on in the Pentagon for about 15 weeks, and then all his money would be gone, and you would have to then liquidate Elon Musk (net worth about $170 billion) to fund the following 13 weeks. The returns on this method of funding would fall off very quickly thereafter.

Also, governments can create money on this scale by diktat. The Biden Administration just signed a stimulus bill around ten times Jeff Bezos’ entire net worth. The description of currency such as the dollar as “fiat currency” is somewhat overused by people pushing fringe economic ideas, but there is truth to it – for situations like this a government simply says “let there be $2 trillion” and as if by magic it appears.

No Easy Answers

Billionaires aren’t going to save the planet because they can’t. If their wealth were enough to decarbonise the economy then governments would simply will that amount of money into existence and do it. So it doesn’t matter at all that some of them choose to spend their money on making humans a spacefaring species. Nor does it really matter than the US spends $20 billion or so each year when the US government can conjure up 100 times that much at the stroke of a pen. Neither public nor private spending on space is stopping the necessary environmental policies being implemented.

Whenever someone asks why society can’t do X, where X is saving the environment of sending humans to Mars or whatever a person cares dearly about, I think the more pertinent question is why society can’t seem to do anything. Aside from maintaining the status quo, western governments don’t seem to be capable of any sustained actions on anything – something painfully demonstrated by many of them during the current pandemic, which was seen off swiftly by different societies in the Far East. Both decarbonisation and space development are worthy goals, and I don’t think its helpful to play them off against each other.

A Flash In The Cosmic Pan

Part of my upcoming book explores the long term trajectory of a future human civilisation. This inevitably runs into the issue of the Fermi paradox; if we have a future as an expanding interstellar civilisation, then presumably any intelligent species that evolved before us could also have had that future, and we should see evidence of them. The questions of our own future and the present lack of clear technosignatures from astronomy are inseparable.

Once humanity has escaped the gravity well, I expect mass value to go exponential, because having more mass under ones command allows more energy to be collected, and having more energy allows one to liberate more mass from celestial bodies and do things with it. Energy consumption would then also go exponential. An unchecked exponential civilisation would fill the galaxy pretty quickly; in a few thousand years at single digit percent growth. However, it will in fact be checked over time.


Consider the energy consumption of an interplanetary civilisation made of up lots of disparate parts; planets, habitats of all possible types with different cultures and economies. The civilisations power (its rate of energy consumption) at any time can be expressed as

Where each g is the growth factor of a part of the civilisation and each A is a constant representing its energy consumption rate at time t=0. Over time, the total energy consumption will tend towards being equal to the fastest growing component only. This means that, as distant observers over long enough timescales, we can treat each civilisation as a monolithic energy consumer growing at a single rate.

We do not need to speculate about what happens to the other parts of the civilisation – if they are wiped out, assimilated, or if they coexist. Its simply that they don’t matter from the perspective of total civilisational energy consumption. Taking this very zoomed out view removes the need for excess speculation about what extra terrestrial civilisations might actually be like in terms of politics, economics etc. It might be the case that a particular civilisation has no part of it that grows exponentially; that doesn’t matter either – as we simply won’t see such a civilisation. From the perspective of the Fermi paradox all that really matters is an ‘ergovore’ civilisation that is driven to expand its energy base exponentially, and which would make itself known by through large technosignatures e.g. the dimming of stars due to the construction of Dyson swarms. That is what we need to explain that lack of.

An energy hungry civilisation that is capable of interstellar travel would expand outwards looking for new stars to power itself. It would have some maximum speed it could expand – physically this is the speed of light but practically would likely be slower – and so the energy it could gather in this manner would increase over time in proportion to the cube of this speed, as the spherical volume of stars it could potentially access expands. And here is the crux of this discussion – an exponential function always outpaces a cubic function.

Below is a figure to illustrate when this crossover happens; a civilisation begins with 1 solar luminosity of power (i.e. a Kardashev level 2 civilisation) and then expands into a region with a constant power density of 1/200th of a solar luminosity per cubic lightyear; roughly what we see in the region of our Sun. Once this crossover is reached, then as a matter of physics the exponential expansion ends. I’ll discuss more about what happens at that stage later; for now let’s just say the civilisation cannot continue growing outwards.

The solid line is represents expansion at the speed of light. The dotted lines represent expansion at 0.9, 0.75, 0.5 and 0.1c.

What this shows is that even with very high speeds, and very modest growth rates (compared to what is likely possible for spacefaring civilisations) the crossover is at a fairly short distance on galactic scales – Earth is about 30,000 light years from the centre of the Milky Way to give an impression of the scale. The above plot is also quite generous in allowing cubic growth to continue for thousands of light years. In reality, the density of stars drops off as you get further from the disk, so even on the scales shown here the increase in power available would drop from a cubic to being closer to quadratic.

This model essentially simplified the Fermi paradox by limiting the volume over which it is required to operate. We only have to explain the lack of aliens within a relatively small bubble instead of the entire galaxy or the entire universe. Of course, we can’t know for sure the maximum growth rate of a civilisation to input into the model – but we can perhaps do the reverse, define an volume in which we are confident there are no signatures of Kardashev 2+ civilisations, and then figure out what combinations of growth rates and speeds to exclude.

The Centre Cannot Hold

What exactly happens at the crossover point is hard to say exactly. It’s tempting to think there is a dramatic collapse, thanks both to Asimov and his Foundation series, and the fact Western civilisation hasn’t really got over the fall of Rome.

It’s been 1,500 years. Time to move on

That narrative is certainly possible – it’s made no more or less so by how much it appeals to us intellectually – but there are other courses it could follow. Maybe there is a stagnation, or a secular decline in population. Maybe new technology eases the needed to acquire more energy. We can’t generalise about all possible alien civilisations.

What I think can be said is that it is not possible to pass the crossover by reducing growth rate such that it does not overtake the cubic energy supply. The reason is that the issue of overshoot is a global property of the entire light years wide civilisation; whereas exponential growth is a phenomenon local to each solar system, because solar systems will not be fully exploited as the sphere of the civilisation expands. The original formulation will apply locally to each solar system, producing an ergovore. To prevent this is a coordination problem between parts of a civilisation that are causally separated by years or perhaps centuries. It’s reasonable to assert such a problem hasn’t been solved in our galaxy.

It’s Not The End Of The World

This might seem like a gloomy prognosis for the otherwise hopeful project of space colonisation. But I don’t see it that way. There is plenty of room to grow until then, and the end of such growth is not necessarily the end of everything. Even if it were so – does it matter that civilisation is mortal on a long timescale? We already know that as a result of cosmology. Eventually the universe will just be too cold to support anything. I don’t find any despair in this either though.

I am planning to work in this model; perhaps apply it to an actual model of our galaxy to get a feel for how stellar density drop off as you expand outside the disk changes things. I also welcome any feedback or discussion on this idea.

It Is My Freesponsibility To Review ‘Libra’

In the far future of 2003, the Earth is falling apart under the mismanagement of a global planned economy, suffering constant power cuts and famines – but there is hope in the stars, in the form of a libertarian Bernal Sphere called ‘Libra’.

This 40 minute short film, made in 1978 by a libertarian group named World Research, was intended both to promote the ideas of rotating space habitats put forth by Gerard K. O’Neill (who served as a technical consultant) and to function as unabashed libertarian propaganda. The story follows two visitors to the eponymous space colony; a businessman considering investing in a second colony, and a senator, Mr. Gordon, representing the straw-man socialist government in charge of Earth. The visuals are fairly good for the time, and the films serves as good introduction to the technical aspect concept of large rotating habitats in space.

Libra showcases some ideas for space development, such as on orbit manufacture, pretty well. It also features a home speaker system on the colony not unlike Amazon Alexa used exclusively for shopping, although in one scene it flaty refuses to recommend a product on the basis that this is the users ‘freecision’ and it can only give factual information. The same scene coins the term ‘freesponsibility’, hence the title of this post.

Solar Flares

The film is quite dated, not just by the ropey special effects or the 70s fashions, but also by its focus on the political obsession of the time. Earth is subject to strict energy rationing – except of course for the agency who is in control of the rationing program, whose lights remain on at all times. Libra offers a solution by providing space-based solar energy, where giant solar panels in Earth orbit convert sunlight to microwaves and beam it to receivers on Earth. These facilities would be too large to be practically launched from Earth, so manufacturing them at Libra from materials mined on the Moon is cheaper. This was how O’Neill originally envisaged paying for his rotating habitats.

Whether this business model is even possible is controversial. Elon Musk, who is heavily invested in both spaceflight and solar energy and generally considered a savvy businessman, thinks its “the stupidest thing ever“. There have been suggested niche applications such as military bases or disaster sites, and perhaps the economics will shift in its favour once space resources are available to build the things, but it is far from the clear cut win that it was assumed to be by Gerard O’Neill and the makers of Libra.

The 70s was a time of fuel crises throughout the west, and the notorious three day week in the UK, which is very reminiscent of the electricity and heat rationing depicted in the film as a permanent global phenomenon. This didn’t continue much beyond the time the film was made though; the US changed its relationship with Arab countries to get the supply of oil flowing again, North Sea oil helped pull the UK out of its energy crisis, and France dived into nuclear energy to protect itself from such shocks in the future.

Likewise, overpopulation and mass famine which are alluded to in the film turned out to be false alarms as well. The Green Revolution averted the worst predictions from the 60s and 70s. Essentially, the creators of Libra offered up their political ideology as the one and only solution to problems of the day which, with the benefit of hindsight, were actually temporary and fixable within the existing political system (more or less).

And Everybody Clapped

The climax of the film features a televised debate between Senator Gordon and the stations leader Dr. Baker. After the senator offers some fairly weak arguments, Baker responds with a lengthy denunciation of the planned economy of Earth, during which Gordon sits there, does not interrupt once, and looks somewhat ashamed of himself. He is stunned into silence by the force of his opponents words.

This never happens in reality, but keeps happening in a certain type of polemic fiction. I recall The West Wing being especially egregious at it. There seem to be quite a lot of people who think debates ought to play out this way, and when you get two or more of them debating on, for instance, a US cable news channel, they tend to end up screaming at each other like crazy people. Those who have bought into this fantasy can get very upset when their opponents refuse to play their assigned role in it. How dare you argue back! You are supposed to wither before my amazing arguments!

What is notable though, is that the strawman enemy that Libra constructs, while exaggerated and lacking a proper advocate in the story, does have some element of truth to it. There really were degrowthers, rationers and overbearing planners in the 1970s, and there still are today. Even if their solution were not right, the makers of Libra had some correct observations about the problems of their day. I think this is true of a lot of people’s politics. A cynical take might be that the democratic landscape is dotted with terrible ideas on how to run a society, and your politics is mostly defined by which of these ideas you hate the most.

Who Turned Out The Lights?

Beginning with Paul Ehrlich’s 1968 Malthusian book The Population Bomb which predicted inevitable mass famine throughout the world by the 1980s, there was a growing movement in the 1970s that thought the Earth had reached its carrying capacity and future growth was impossible. At the time Western economies had begun to falter, and the Eastern bloc had entered a deep economic stagnation from which it would never recover – so this would’ve been an easy thing to believe.

At around this time the Club of Rome was founded and published its famous Limits to Growth report. India and China implemented draconian population control methods late in the decade. A sense that the world economy was finite, limited and zero-sum arose at arouond the same time as environmentalism entered public consciousness (the first Earth day was celebrated in 1970) and the two ideas became entwined and mutually reinforcing. This trend continues to this day, experiencing a resurgence as the issue of climate change has become more urgent. Greta Thunberg denounces ‘money and fairytales of eternal economic growth’ from the podium of the United Nations, and Sir David Attenborough (patron of the population control advocacy group Population Matters) is given an enourmous platform on Netflix to espouse his view that we have pressed up against the limits of our planet and must curtail both our population and our activities to minimise the damage. This is not at all a fringe idea.

In Kim Stanley Robinson’s latest book The Ministry For The Future he depicts a heroic global organisation of the same name who are required to represent the interests of future generations and thus overturn the effects of rapacious capitalism. They seem to be more or less the bad guys from Libra, but have become good guys because the author is a left-wing environmentalist. I haven’t yet finished this book though; I will write a review when I have as I think its a good counterpoint to this film. The book seems explicitly anti-growth; it makes the case that existing economic output can be enough for all if evenly distributed, and makes positive mention of the 2000 Watt Society, which as its name suggests advocates energy rationing.

Libra therefore serves better as a criticism than as a positive statement these days. There is a doom-laden anti-growth trend in the modern left, which worries me being someone who is on most issues classed as left wing. Modelling yourself as the hero of an Ayn Rand novel is bad, but surely modelling yourself as the villain of an Ayn Rand novel is worse.

There Is No Alternative

There really are valid concerns about growth – humanity does have a huge impact on the biosphere – but the idea that all economic growth is destructive does not hold up, because growth can be achieved by doing more with the same resources. In the 70s, the development that allowed this was not the O’Neill cylinder, nor was it libertarian politics – it was the microchip. The first commercial microprocessor, the Intel 4004 was released in 1971 and by the end of the decade, practical desktop microcomputers such as the Apple II and the Commodore PET were available. Driven by Moore’s Law, computers were able to generate exponential economic value without requiring exponential resource inputs. Its not clear what could do the same now – biotech perhaps – but it would be premature to announce that such intensive growth is at an end.

So Libra did manage to skewer its targets fairly well, to the extent that its criticism could still be applied to their modern day ideological descendants, but it lacked the self-examination necessary to consider that there could be any solution to the problems it pointed out other than its writers’ ideological and technological preference. They are hardly alone in this conceit of course; its all too common to claim ones pet policy is a matter of strict necessity rather than choice.

There is certainly a warning here for advocates of space settlement – its easy to trap oneself in wishful thinking, mentally closing business models based on incorrect assumptions because you just want things to happen. I hope that I can avoid that in my own work.