If you noticed I have done a lot of Venus art - it's because I believe Venus is actually a much better colonization target, while Mars is a dangerous waste of time, at this time in our history (eventually, we should also go to Mars, but after Venus). I wrote and article on this topic, figured I would share here. (Also, if anyone can tell me how to make this ridiculously large font smaller, that would be great, thanks!)
originally written here:
A few hundred years in the future, I imagine that our descendants will be able to fix almost any problem with a planet - atmospheric composition, lack of water, temperature - but there are a few things that will remain out of our reach for at least many millennia, changing a planet's size (and location). Unfortunately for Mars, it's size is actually it's biggest problem, and conversely, it's Venus's biggest asset.
Without proper gravity, mammalian babies don't develop properly, or at all, and mammalian lifespans are greatly shortened and plagued with serious health problems. We know this both from common-sense, basic biology, and scientific testing in micro-gravity. Yet, despite it's importance, gravity seems to be the most ignored challenge in the quest for exploring and colonizing Mars. Why? Because if Mars' gravity is too weak for humans to gestate properly, causes most children to be born maimed and defective, and/or results in many colonists living short miserable lives plagued with health problems, the only thing we can do is ... nothing but pack up and go home. There is no 'fix' that is even remotely within our technological capability. In fact, if we find a way to test the long term viability of living in Martian gravity, and find out humans can't reasonably do it, the entire Mars colonization project that so many people today are obsessed with is a bust, and the dream of space colonization in the near future will probably die with it.
Much-maligned Venus doesn't have this unsolvable problem. In fact, it lacks many of Mars' problems. Because it's size, Venus has normal gravity, similar to that of the Earth. Like on Earth, this gravity has also held on to a thick atmosphere capable of protecting people from solar radiation, cosmic rays and meteorites (that, on Mars, can cause a pressurized habitat to explosively fail, killing all inside). Venus is also closer to Earth (a journey to Venus takes 1/2 as long as a journey to Mars) and has hospitable, 30C temperatures and endless open sky. To go outside, colonists wouldn't even need a space suit - only an oxygen mask. Sunshine, blue sky, and the ability to walk outside? How about not having to run to a shelter every time there's a solar storm, risk a long painful death from radiation induced cancer or live in fear of a meteor strike causing your habitat to decompress / explode? Mars can't offer these benefits.
But what about the extreme pressure and 430C surface temperatures that everyone seems to agree makes Venus 'uninhabitable'? It's simply a problem of looking in the wrong place for habitable areas. What if we judged Earth's habitability for humans by looking at the bottom of the ocean, or inside the magma chambers of volcanoes? We'd also see temperatures and pressures unsuitable for human life. But the Earth is clearly habitable for humans. Venus can also be surprisingly welcoming, if you simply look in the right place. On Earth, the best place to live is on land, on Venus, it's in the sky.
50-55 km above the surface of Venus, there is little sulfuric acid virga, tellurium snow, or lead melting temperatures - all fascinating but deadly traits of the Venusian surface. While Venus colonists might do some extreme exploring down below, their colonies would be in balloons filled breathable air - which naturally float in Venus' heavy CO2 atmosphere. The ballons would have similar pressure to the outside atmosphere, so if they were damaged or developed a leak, they would not explosively decompress (killing all inside), unlike a Mars habitat. With the right adjustments, these balloons would hover comfortably in the habitable region of the atmosphere, enjoying temperatures ranging from 75C to 19C, depending on how high up the colonists want to float. If the balloons were free floating, they would travel on the winds around the planet every 4 days, giving the colonists a regular day / night cycle.
... and again, unlike Mars, all of it could be done with existing technology. The short travel time to the planet means less muscle degeneration from micro-gravity, less radiation risk during travel, and less fuel needed - making the trip well within our current rocket technology. Venusian colonies would also be made primarily of balloons filled with air, a technology humans have mastered for over 300 years. Constant sunny skies and plenty of CO2 would make growing plants relatively easy. There is less accessible water on Venus, but it can be extracted from the sulfuric acid clouds in the atmosphere, a chemical process that we already understand. As for the long term, by the time we're actually ready to start terraforming a planet, our technology will have developed to the point that both Venus and Mars will be within our ability to change.
In the end, both planets are imperfect, but while Venus's long-term terraforming challenges may be more daunting, it's a far more attractive short-term target for human colonization. Venus has an Earth-like, habitable region. Mars does not.Mars advocates want us to bang our heads against the wall trying to conquer a hostile and unwelcoming wilderness like Mars, willing to risk the entire enterprise of planetary colonization before it even gets off the ground to get their way with a planet that can't even support us now. Why should our civilization, with no experience in colonizing or even manned exploration of other planets, jump into a dangerous venture like Mars at the behest of fantasy stories told by Mars dreamers? A safer, closer, easier to reach, 'starter planet' is silently waiting for us to set up our new home floating over puffy white clouds and through endless blue skies.