Space, it has intrigued and mystified us for thousands of years, today we are on the cusp of change. Soon, we will no longer be visiting space, we will be living there. Russia, China, and the United States have plans for colonization of the nearby planet Mars , and the organization Mars-One has plans of a human colony on the red planet by 2025 . However, is Mars the only option? Throughout article I lay out two possibilities for future colonization. Mars and Venus.
Mars is the planet most commonly discussed on the topic of colonization. The fourth planet from the sun, Mars is 225,300,000 km from the earth .
However, is colonization of Mars even possible, and could Venus be the better option?
Perhaps the largest benefit of Mars is the recent discovery of frozen water in its soil . This water would be essential for human life. Mars’s atmosphere is wispy and almost non-existent as well as being only 0.4% oxygen . However, oxygen could be extracted from the water, supplying colonists with breathable air . While oxygen may not be an issue there are a few other problems with a Mars colony. For example, Mars has very little atmosphere, resulting in the atmospheric pressure being far below the level where people can survive without pressure suits , also the temperature shifts between −87 °C and −5 °C , making it completely unable to support any plants or animals that could be of any use. However, with the construction of pressurized chambers, and the use of space suits when outside of structures, people and plants, could live on the red planet .
Unfortunately, there are some barriers that many believe could make long-term habitation of the planet impossible. Mars lacks a magnetosphere like earth. Deep underground, flowing liquid metal creates a magnetic shield around Earth that protects us from the Suns radiation. Because Mars does not have a magnetosphere, colonists would be completely vulnerable to the Suns radiation . We are unsure of how exactly the higher radiation doses would affect people living on mars, however, it would almost certainly result in higher cancer mortality among colonists, as well as other unforeseen effects . The second factor is gravity. The surface gravity of Mars is 38% of Earth’s  and the trip to Mars is about 6 months , which the colonists would spend in zero gravity. The effects of low, or no gravity at all, can be crippling. Without the full effect of gravity, your bones and muscles atrophy much faster (wear away) . On the international space station, astronauts exercise for around two hours every day , yet can still expect a loss of muscle mass as high as 5% per week , and a loss of bone mass at ten times the rate of someone with advanced osteoporosis . Currently, astronauts rarely spend more than six months in space at a time . However, for people living on mars, this rapidly reduced bone and muscle mass, could have horrible effects on their health, and it is unclear if children could be born, and develop in low gravity conditions.
Venus is often called Earth’s sister planet . It is the closest planet to Earth, with a trip to Venus being 30 to 50 percent shorter then to Mars . This means
colonists would spend less time in zero gravity on the trip, and food and supplies would be much easier to get to the planet . However, if you know much about astronomy, you may be surprised that I am even mentioning Venus. Venus is incredibly hot! Do to the massive amount of carbon dioxide, the greenhouse effect makes the surface of Venus average at 462 degrees Celsius, making it impossible for a colony to land on the surface . Also, the thick atmosphere makes the atmospheric pressure around 90 times that of earth , in which any people or equipment would get melted and crushed very quickly. However, about 50 km above the surface of the planet , the pressure drops to about that of earth, and the temperature would decrease to around 70 degrees Celsius . While this is still very hot, firefighting equipment on earth can withstand temperatures of 2000 degrees, and modified suits and oxygen masks could easily deal with the heat and potential harms in the atmosphere , all without a spacesuit or pressurized chambers. Finally, due to the thicker atmosphere, balloons filled with helium or even ordinary earth air would float with much more force then on earth, and could support a colony in the atmosphere .
Venus has a few other benefits over Mars. Its atmosphere would provide somewhat better protection from solar radiation  (although it would still be drastically lower then earth), as well as protecting a colony from asteroids , which would burn up in the atmosphere and not pose a risk to the colony, like it would on Mars. Venus is also much closer to the sun, resulting in almost four times the solar power potential then on Mars  (which would almost certainly be used to power the equipment). However, the largest and most important reason why Venus may be a better colonization target then Mars is its gravity. Venus’s gravity is around 90% of earths, making the negative aspects of low gravity irrelevant . Also the shorter distance between Earth and Mars, would mean less exposure to zero gravity on trips there and maybe even trips back. We are unsure how Mars’s gravity will affect people living there long term, however, most likely, they would be unable to return to Earth do to the loss of bone and muscle density, Earth’s gravity would crush them . This is why all planned Mars missions are one way trips, with no plans for a return to Earth. With Venus it may be viable to have people return from the colony. However, Venus is still not a perfect option. For example, access to water would be much easier on Mars . While Venus’s atmosphere it very heavy in carbon dioxide from which oxygen could be attained , water would not be available on the planet. For a Venus colony to exist, water would have to be transported to the planet along with food and equipment. However, supply trips to Venus would be much shorter and much less expensive than a trip to Mars and Mars would have to rely on earth for food and equipment as well . Since constant resupply missions would be necessary for both options, this is less of an issue. Finally, a day on Venus is 116 earth days ! Resulting in months of darkness, followed by months of daylight. On Mars on the other hand, has a day night cycle only 40 minutes longer then earth ! On Mars people could sleep in tune with the sun, and get more benefit out of solar power. Mars also has a shifting axis, resulting in four seasons , Venus however does not experience seasons.
In conclusion, both options have positive and negative aspects, however Mars seems to be discussed much more often. However, Venus is not completely ignored. NASA has released plans for a human colony on Venus called HAVOC, or High Altitude Venus Operational Concept . However, NASA’s plans, and the rest of the scientific community remains focused on Mars, and if this plan came to fruition, it would be done complementary to Mars missions not as a separate project. In the end, any colonization effort of space would be revolutionary and beneficial for all of human kind, however, its important that we don’t get too focused or obsessed with one option or idea, we need to keep our minds open and look at all the opportunities before us.
Do you think we should focus colonization efforts on Mars or Venus? Why or why not?
What are some other options for space colonization I chose not to mention in this article?
Are you for or against space colonization? Why?
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