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B Venus -- a more attractive target than Mars for human colonization?

  1. Jan 7, 2017 #1
    If Venus had an atmosphere similar to that of Mars, would Venus then be a more attractive target than Mars for human colonization?
  2. jcsd
  3. Jan 7, 2017 #2
    yes and No. yes Venus is the same size, mass as Earth but it is 44 million miles closer to the sun. therefore No Venus has a runaway greenhouse gas atmosphere which is unlikly to change ever! Also the hemisphere facing the sun is constantly at above 400 Celsius.
    the conditions are unlikly to change and the atmosphere creates a pressure of 3- 4 x that of earth's atmospheric pressure.
    In conclusion I would say no to habitation of Venus over Mars.
  4. Jan 7, 2017 #3


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    Some thoughts:
    • Getting to Venus: Faster and slightly easier, assuming you use the atmosphere to brake.
    • De-orbiting and landing is more challenging as you start with a much higher orbital velocity (-> more stress for heat shields) and the gravitational attraction is stronger.
    • Communication: A bit easier and faster as Venus is closer than Mars.
    • Length of day: Bad, really bad. Venus days are 117 Earth days long. Without its thick atmosphere, the day side would get very hot (probably not as hot as it is now, but still uncomfortable), while the night side would get really cold. You would have to land close to the poles, bury deep under the surface, or use a lot of power for cooling during the day and a lot of heating during the night. Solar power is also impractical unless you have a massive electricity storage. Mars has a rotation period of 24 hours 30 minutes, which means you don't have all those issues, and you can even have a regular day/night sleep cycle.
    • Access to water: Looks quite easy on Mars, dig a few meters down and extract ice from the ground. Venus doesn't have large water supplies, but this could be different for our hypothetical Venus with a Martian atmosphere.
    • Getting back: You can easily get from Mars back to Earth with a single-stage rocket. You can get back with the same rocket that brought you to Mars (see SpaceX's ITS plans). For Venus this doesn't work. You would need rockets as massive as the rockets for Earth->Venus. Colonization would be a strict one-way trip until the colony is advanced enough to assemble massive rockets.
    • Very long-term considerations: Adding a convenient atmosphere is easier on Mars because Mars is smaller, but on Venus you get more surface area - the effort per surface area is similar. An artificial magnetic field to protect the atmosphere is possible in both cases, but easier on Mars (here the size, the larger distance to sun and the colder climate help a lot). Surface water on Venus: Maybe closer to the poles, where the temperature does not rise that much. Surface water on Mars would be easier.
  5. Jan 11, 2017 #4
    In terms of size and distance, Venus is better. However, the surface conditions on Venus is much more horrible than that on Mars, especially the atmosphere there. The atmospheric pressure on the surface of the earth is approximately 1 bar while that on Venus is 93 bar. And the thickness of the atmosphere there is over 200 km. I think the "modification" of Venus is much harder than that of Mars, merely in terms of atmosphere.
  6. Jan 11, 2017 #5

    Vanadium 50

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    See above.
  7. Jan 13, 2017 #6
    However, viewed in a different way, the problem with Venus is merely that the ground level is too far below the one atmosphere level. At cloud-top level, Venus is the paradise planet.”

    The atmosphere of Venus has a sweet spot at 50km altitude where the temperature and pressure are Earth-like and the atmosphere at that level circles the planet in four Earth days.
  8. Jan 14, 2017 #7


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    You cannot land a craft 50 km above the surface of Venus.
  9. Jan 14, 2017 #8
    With a large craft / habitat / Teflon balloon / cloud city full of air at or near the standard temperature and pressure we like at the earth's surface... you float nicely at that altitude because atmosphere of Venus at 50km matches that of your living environment. It's warm, 140s F, but just three km higher and the temperature is in the 80s F.
  10. Jan 19, 2017 #9


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    I'm not sure I'd like to live there! Pretty weird. And what would be the point, there are no resources to exploit.
    Maybe they could construct the quirkiest hotel ever. Crazier than the Ice Hotel!

    But, could we genetically engineer organisms - or I suppose I really mean, evolve new species - to float at that altitude and grow like plants? Collecting dust like some epiphytes do, conserving water like a cactus, having a float bladder like a Man o' War or kelp? It would need to sense and adjust it's altitude. O2 is less dense than CO2, so the bladder could be filled with O2 that it gets from photosynthesis.
    If we did, what would the effect be on Venus atmosphere and climate?
  11. Jan 19, 2017 #10


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    We are at least decades away from creating completely new multicellular species. Putting some molecular processes from species A into species B works sometimes (e.g. insulin production), but that's all we can do today.
  12. Jan 22, 2017 #11
    Venus!? ... Not a good idea! ... (for now)

    She may look pretty and attractive from here ..., but ... not even close to friendly when you get there! ...
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