Human colonies on Mars are a bad idea

In six months time it will be exactly 50 years since human beings last set foot on the moon. It will also be 50 years since humans last ventured outside Earth and its immediate surroundings. Since the Apollo missions to the moon no human has been further away than Low Earth Orbit, approximately 500 km above Earth’s surface.

This state of affairs is about to change. At least if you are to believe the hype. Although planning for new space adventures never stopped after the Apollo program there was a noticeable lack of enthusiasm after the moon had been conquered by human engineering.

Today the enthusiasm for big space projects is back. NASA has a new moon program with the stated goal of exploiting the moon’s resources for further advances in space. Admittedly, other officially stated goals of the project are to place the first woman and the first person of color on the moon’s surface. We are still on Earth, after all.

But NASA is not alone in space and the Moon is just a way station on the road to greater goals. Today everyone wants to go to Mars. Not just NASA, as could be expected, but also private interests, mostly incarnated by Elon Musk, owner of SpaceX, the world’s foremost space launch entity. But the lure of Mars is not limited to major players. Everyone wants to go there. Even the United Arab Emirates has a Mars Program.

Next stop: Mars

Why does everyone want to go to Mars? There are of course many scientific reasons to investigate the red planet. It is the planet most similar to Earth and might therefore shed valuable insights into our own history. It is also another celestial body, and unlike the moon it is not closely related to Earth which means it could also teach us a lot about space and other worlds.

But the main reasons most people want to go to Mars seem to be for fun and profit. Fun, for the adventure of it. And profit, for the possibility of establishing human colonies on Mars. Elon Musk has been quoted saying that he wants humans to be “a multi-planet species” rather than one of those pitiful organisms that only exist on a single planet.

This logic seems sound enough. After all, Earth has its fair share of problems and it might be a wise strategy to have some sort of back-up planet if all else fails. In fact, one of the main criticisms of Mars colonies, at least in the media, seems to be that it might take focus from Earth’s problem by offering a shortcut to another future.

But sceptic voices are probably a minority. Most media coverage is positive of human travel to Mars and the possibility of future colonization. Some reporting goes as far as stating that the survival of the human species depend on our ability to colonize another planet.

This might be a slight exaggeration but clearly the redundancy of having another planet to live on should be viewed as a positive. After all, there are planet destroying incidents, most obviously asteroid impacts, with the capability of destroying all life on Earth. Anything we can do to mitigate the risk of going extinct as a species is good, right?

The downside

While human colonies on Mars are not negative by themselves they are not a net positive either. Most people understand that there are great costs involved in putting humans on the surface of Mars and an even greater cost to establish a sustainable human presence on Mars. In fact, the latter ambition might not be realistic at all. At least not with current human technology and resources.

The dirty little secret of Mars colonization is that Mars is an inhospitable place. More inhospitable than might be realized at first glance. Most people will be aware of the fact that Mars lacks an atmosphere suitable for humans. That is a problem, but not a major one. It is entirely possible to live a life indoors or use a space suit if you have to go outside.

Unfortunately, human colonies on Mars have more severe problems than the lack of breathable air. Here are the three I believe most likely to wreck the whole idea.

1.  Mars lacks a magnetosphere. The atmosphere on Earth protects us from some types of radiation. But we receive most of our radiation protection from the magnetic field surrounding the entire planet, our magnetosphere. Mars has no magnetosphere at all and only a very thin atmosphere. The Mars surface is therefore exposed to the full force of cosmic radiation. While the dangers of cosmic radiation might be exaggerated it is clearly not beneficial to live your entire life in such an environment. Humans that want to live on Mars therefore need protection in their everyday life. This protection will probably involve living underground.

2.  Mars' gravity is too weak. Mars is significantly smaller than Earth and has a gravity only 38% of the gravity on Earth. While this is still better than the moon (16.6% of Earth’s) it is still not very much. No one knows exactly how this level of gravity will affect human beings. But given that humans have evolved to handle the 9.81 m/s² gravity on Earth, chances are the health implications of living an entire life in 3.71 m/s² gravity will be severe.

3.  Mars is too far from the sun. The average distance of Mars from the sun is about 50% more than Earth’s distance from the sun. This might sound like a detail but it means that the solar energy per square meter on Mars (586.2 W/m2) is less than half the corresponding value on Earth (1361.0 W/m2). The solar irradiance at the equator of Mars is about the same as on Svalbard in the far north of Earth. Few plants and no agricultural plants grow on Svalbard. The same will be true on Mars which means that all forms of agriculture will have to be done under artificial light (which might also be necessary due to the lack of magnetosphere, most plants do not like radiation).

Especially the weak sunlight is a major problem for every aspiring Mars colonist. Farming under artificial light might not be a great inconvenience if there is plentiful energy available. But the distance from the sun also makes Mars starved of energy.

Due to the weak sunlight solar panels on Mars are very inefficient. NASA researcher and Mars colonization enthusiast Robert Zubrin states frankly in his book The case for Mars that solar panels are a non-starter. Instead he suggests nuclear reactors. According to his calculations one small nuclear reactor could supplant solar panels weighing a hundred times as much. If you have to lug all your equipment from Earth that is a very big deal.

Down the rabbit hole

There is uranium on Mars. A Martian civilization could theoretically mine uranium and create all the energy it needs in nuclear reactors. Food could be grown under artificial lights and people would live in indoor areas buried deep underground, well protected from both cosmic radiation and Mars’ lack of atmosphere.

But what life would these underground settlers live? They would spend almost all of their lives indoors with the health risks that entail (for example myopia) and they would do so in an unknown environment with unknown long-time consequences.

In fact it is rather unnecessary to go to Mars to live this kind of life. It is perfectly possible to create self-sustaining societies deep down in the Earth’s crust as well. Depending on the depth the protection from planetary catastrophes could be just as good as a colony on Mars. Obviously, it would also be much cheaper to build a colony on Earth rather than on Mars.

A Veblen good is a good that becomes more desirable the more expensive it is. You do not buy a Veblen good for its utility but for its ability to impress. In many ways Mars colonies can be viewed as a Veblen good: They are attractive not because they are good value for money but because they show how much money we have committed to spend. Maybe Mars colonization could be termed a collective Veblen good, something we as a society spend resources on in order to impress ourselves.

In this it would not differ very much from religious offerings of history. In the past we would offer our surplus resources to the gods. Today we offer our surplus resources to the god of science. Not primarily to enhance science but to show that we still believe in science. There is reason in this madness. But not enough to make Mars colonies a good idea.