Mars or Venus: Which is a Better Home for Humanity's Future?

Republibot 3.0
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Here at Republibot our mandate is to ask questions that no one else is asking; ideally the painfully obvious ones that no one even *thinks* to ask. To that end, I have to think it’s well beyond time to question what the appropriate focus of our manned space program should be: Mars, or Venus? The common wisdom, of course, is “Mars! What the hell is wrong with you? Why would you even ask such a thing?” But of course the Common Wisdom is Common simply because no one ever questions it, not because it’s inherently right. We’ll discuss the Pros and Cons for each planet under the jump.

It is taken as axiomatic in Science Fiction that humanity’s future lies in space. If that assumption is really the case, then a fundamental failing of NASA – and indeed every Space Agency in the world – is that everyone is talking about exploration and no one is talking about colonization. In fact, the last NASA symposium on that subject was in 1977, a full thirty-two years ago! The Soviets never discussed it as far as I can tell, and the Russians are far too pragmatic and cash starved to even joke about such things. The Chinese Space Program is likewise barely soldiering along, so the idea is not even a blip on their radar at the present, insofar as we can tell.

Granted, in a world that hasn’t even visited its own moon in thirty-seven years, things like “Space colonization” do seem a bit grandiose, but the desire to at least check out the apartment is hardwired in to us, even if you don’t have the money to move there. So we sublimate our inherent primate desire for territorial expansion with the code word “Exploration.” We’ll not go to the Moon or Mars to claim it for the US or Mother Russia, instead we’ll go simply as lookey-loos, in the sake of science, ostensibly trying to find evidence of long-extinct extraterrestrial life or subterranean water, which may not exist in the first place, rather than for any of the more bankable reasons that people actually give a damn about.

But inasmuch as we talk (And talk. And talk. And talk some more) about manned exploration of space without ever actually doing anything about it, the target of choice is always Mars. And there’s always some mumbled sentiment about how “Mars is the future.” We hear this so much, and for so long now – more than half a century – that we tend to accept it without thinking, much the same way that Democrats automatically assume all Republicans are stupid, and the way most people believe all French people are rude. Mars is the logical choice, right? Yes? Isn’t it? I mean, it’s *such* a logical choice that people have ceased to consider any other option. It has become the *only* choice. From where I sit, having just one choice is pretty much the same as having no choices at all, and I recoil from that idea. So let’s look at our options, shall we?

First, as a baseline comparison, let’s take a look at our own planet: - Our diameter is just shy of 8,000 miles, our breathable atmospheric pressure is just under 15 pounds per square inch at sea level, and our average surface temperature is a surprisingly low 57.2 degrees. Our day is 24 hours, and our year is 365.25 days. Our gravity at the surface is 1G. There is lots and lots of liquid water because of this high gravity (Earth is the densest object in the Solar System this side of people who voted for Hillary in the primaries), and our ‘gravity well’ is deep enough that we never loose any of it to space. The same goes for the air: we have a thick atmosphere and a disproportionately strong magnetic field that, working together, screen out nearly all solar and cosmic radiation. It’s home.

Now let’s take a look at Mars: - The planet’s diameter is just shy of 4,220 miles, or a hair over half that of Earth. Such atmosphere as there is on mars is toxic, and the pressure is just about 1/11th pound per square inch at ground level. (Yes, you read that right, it’s that low!), and our average surface temperature is around 51 degrees below zero, Fahrenheit (Though at the equator during a particularly hot summer, it might get up to a balmy 23 degrees above zero.) The Martian day is 24 hours and thirty four minutes, and its year is 686.9 days. Gravity at the surface is .37G. Because of the low density, the planet’s ‘gravity well’ isn’t deep enough to hold on to a dense atmosphere for very long, and eventually the local air ‘outgases’ in to space, leaving behind only the denser, more toxic gases. The same goes for the water: once the atmosphere escapes in to space, the ocean begins to boil in to vapor, which similarly outgases into space. Thus most of Mars’ theoretical water from ages past has left the planet and has become part a lot of unassociated hydrogen and oxygen atoms dispersed through the solar system. Mars has no real magnetic field to speak of. Because of the lack of any real Magnetic field or any substantial atmosphere, practically no radiation is screened out before it hits the ground, and anyone on the surface would take lots of radiation from the sun during the day, and lots of cosmic radiation at night. To put it another way: there is no significant difference between the amount of radiation an astronaut would receive in interplanetary space, and the amount they’d receive simply standing on the surface of Mars: It’s a deathtrap.

Now let’s look at Venus: - the diameter is just shy of 7518 miles, or 94% that of Earth. The atmospheric is poisonous and caustic, with a pressure of 1349 pounds per square inch at ground level; roughly equivalent to the pressure you’d find half a mile under water here on Earth. The average surface temperature is a 863 degrees, higher than the melting point of lead (And this is surprising because Mercury is closer to the sun than Venus, but Venus is hotter). A Venusian day is the equivalent of 243 earth days, and the year is around 270 earth-days. Gravity at the surface is .9G. There is no liquid water because of the high temperature and slow rotation. There is a very slight, insignificant magnetic field, however given the disproportionately thick atmosphere nearly all solar and cosmic radiation is screened out before it hits the ground. A person on the surface of Venus might actually take less radiation than a person on the surface of the Earth.

Let’s be honest: Looked at objectively, neither Venus nor Mars look like an inviting place to vacation, much less spend the rest of your days. Despite more than a half-century of hype, Mars is really just a bigger, more annoying version of the Moon, and Venus looks a hell of a lot like hell. The solar system isn’t exactly brimming over with great real-estate opportunities on Earthlike worlds, I’m afraid: these two options are actually the best we’ve got. So if Jerry Pournelle’s fictional BuRelock put a gun to my head and said “Pick one, or we’ll shoot you” I’d pick Venus, myself.

Here’s why: 1) Mars is about 148 million miles from the sun, on average. Thanks to the inverse square law, that means that Mars is getting less than half as much sunlight as we get here on earth. The planet will be dim and depressing, and there’ll be too little sunlight to usefully grow much in the way of crops, so most food will have to be grown indoors under lamps. At the same time, living on the surface I’ll be taking something like six or seven times as much radiation as I do here on earth. Screw all those cool 1950s illustrations of bubble-domed surface colonies: any long-term Martian settlement is going to be underground. If I’m going to spend my whole life indoors without natural lighting anyway, one planet is as good as another.

2) Radiation: not to overstate it, but I can go to Mars, be subjected to ungodly amounts of radiation, get cancer, and die early, or I can go to Venus and be subjected to no real radiation, and live a long, full life.

3) Gravity: Colonies are all about going to new places, knocking people up, and having babies. Our species evolved for relatively narrow biological confines – too much heat, we die; to little heat, we die; too much pressure, we die; too little pressure, we die – and we don’t tend to notice these constraints simply because we’re still living on the planet we evolved on. One of the variables that we tend not to notice is our 1.0G gravity well. Every single human being ever born or conceived has been so in the same gravity. Conversely, we know that zero gravity is very bad for us, health wise, and while low gravity is probably not as bad as no gravity, we don’t have enough experience on the moon to know exactly how much difference it makes. We have experimented extensively with gestating animals in zero-G, however, and the results are pretty horrific: fish born with multiple spines, horribly disfigured offspring, spontaneous miscarriages, brain damage, cerebrospinalfluid problems. It’s a mess. In essence, when vertebrate life develops, it *needs* a significant gravity field to develop properly. Without this, well, Lovecraftian things happen. At this juncture, we don’t know how much gravity we need, 9/10ths G seems a whole lot more conservative than 1/3rd G, and since we’re gambling with the life of my offspring here, obviously the conservative bet is the way to go.

Bottom line: It may be biologically impossible for humans to have babies anywhere in the solar system other than Earth and Venus.

Of course there are some downsides: The temperature, the pressure, the caustic air, but those are quibbles and they’re frankly not as insurmountable as they’re made up to be. No one has ever built a self-sustaining colony on Mars, yet everyone assumes it can be done. No one has ever built a self-sustaining colony on Venus, yet everyone assumes it can’t be done. Why? Well, frankly, we don’t know since we haven’t tried either, but insulating against high temperature is child’s play: Just make sure the outside of any structure is ceramic, which also takes care of the ‘caustic’ problem. We have literally millions of man-hours living and working under massive external pressure, thanks to the various Submarine Navies of the world. We know this can be done; we have practical experience in it. Building a base on Venus shouldn’t be much harder than building a colony on the sea floor (Which also hasn’t been done, but at least the skills required for such a thing exist in nascent form). The lack of water is a problem, but frankly there’s lots of water to be had in the Solar System: Most of the Jovian Worlds have ice-moons. We simply mine ice there, and haul it back to Venus. Not easy, but within the realm of possibility.

Admittedly, a life on Venus doesn’t sound as attractive as a life on Mars, but that’s only until you get used to the idea that anywhere you go in the solar system, you’ll be living under hundreds of feet of rock. And then it begins to look surprisingly feasible. Finally, from a logistical point of view, Venus is quite a bit more desirable than Mars simply because it’s closer: Mars is 154,851,479 miles from the sun, on average. Earth is 93,000,000, on average. That means that Mars is never closer than 61,800,000 miles to us, and is occasionally as far away as 247,851,479 miles away. That’s a damn long drive in an El Dorado, and everyone knows you can drive them suckers to the moon! Conversely, Venus orbits a mere 67,693,488 miles out from the sun, which means it’s never more than 160,700,000 miles away, and it’s often a mere 25,300,000 miles away! Still a long ride, but rather than a nine-month one-way journey to mars, and a three year round trip, we’re looking at a four-month one-way journey, and a nine-month round trip. There are also considerably more launch windows available to Venus than there are to Mars. With Mars, there’s one every eighteen to twenty months, with Venus there’s one third more on average. What this means is that it’s simply easier and shorter to get to Venus, which means less time for things to go wrong, and much easier to haul colonists and equipment to and from the planet than you’d get with Mars.

And I’m not being glib when I say “Possibility of anything going wrong” – there have been 38 unmanned missions to Mars in total, and only 19 of them have succeeded, the other fifty percent failing, or crashing, or simply being lost in space. I’m not willing to take those kinds of risks with human life. Venus is simply an easier, closer, more conservative target, and it’s an order of magnitude safer than going to Mars. In other words, if we started Colonizing Mars and Venus today, launching three people every time a launch window opened up, then in ten years we’d have 18 people on Mars, but we’d have 27 people on Venus. This ease of accessibility is a major consideration to any kind of colonization process, which is why North America filled up faster than South America or Australia.

So that’s my reasoned opinion. What do you people think? Sound off in the comments!

Sincerely, Republibot 3.0