page_title: Colonization of Venus
section_title: Advantages
hierarchical_section_title: Colonization of Venus / Advantages
context_page_description: The colonization of Venus has been a subject of many works of science fiction since before the dawn of spaceflight, and is still discussed from both a fictional and a scientific standpoint. However, with the discovery of Venus's extremely hostile surface environment, attention has largely shifted towards the colonization of the Moon and Mars instead, with proposals for Venus focused on colonies floating in the upper-middle atmosphere and on terraforming.
context_section_description: Venus has certain similarities to Earth which, if not for the hostile conditions, might make colonization easier in many respects in comparison with other possible destinations. These similarities, and its proximity, have led Venus to be called Earth's "sister planet".
  At present it has not been established whether the gravity of Mars, 0.38 times that of the Earth, would be sufficient to avoid bone decalcification and loss of muscle tone experienced by astronauts living in a micro-g environment. In contrast, Venus is close in size and mass to the Earth, resulting in a similar surface gravity (0.904 g) that would likely be sufficient to prevent the health problems associated with weightlessness. Most other space exploration and colonization plans face concerns about the damaging effect of long-term exposure to fractional g or zero gravity on the human musculoskeletal system.
  Venus's relative proximity makes transportation and communications easier than for most other locations in the Solar System. With current propulsion systems, launch windows to Venus occur every 584 days, compared to the 780 days for Mars. Flight time is also somewhat shorter; the Venus Express probe that arrived at Venus in April 2006 spent slightly over five months en route, compared to nearly six months for Mars Express. This is because at closest approach, Venus is 40 million km (25 million mi) from Earth (approximated by perihelion of Earth minus aphelion of Venus) compared to 55,000,000 km (34,000,000 mi) for Mars (approximated by perihelion of Mars minus aphelion of Earth) making Venus the closest planet to Earth.
  Venus's atmosphere is made mostly out of carbon dioxide. Because nitrogen and oxygen are lighter than carbon-dioxide, breathable-air-filled balloons will float at a height of about 50 km (31 mi). At this height, the temperature is a manageable 75 °C (348 K; 167 °F); or 27 °C (300 K; 81 °F) if we could get 5 km (3.1 mi) higher (see Atmosphere of Venus § Troposphere). 
  The atmosphere also provides the various elements required for human life and agriculture: carbon, hydrogen, oxygen, nitrogen, and sulfur. 
  Additionally, the upper atmosphere could provide protection from harmful solar radiation comparable to the protection provided by  Earth's atmosphere. The Atmosphere of Mars, as well as the Moon provide little such protection.
caption: Scale representations of Venus and the Earth shown next to each other. Venus is only slightly smaller.
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