section_path: Human presence/Habitation
section_name: Habitation
paragraph_text: Habitation
  
  While the surface conditions of Venus are inhospitable, the atmospheric pressure, temperature, and solar and cosmic radiation 50 km above the surface are similar to those at Earth's surface. With this in mind, Soviet engineer Sergey Zhitomirskiy (Сергей Житомирский, 1929–2004) in 1971 and NASA aerospace engineer Geoffrey A. Landis in 2003 suggested the use of aerostats for crewed exploration and possibly for permanent " floating cities " in the Venusian atmosphere, an alternative to the popular idea of living on planetary surfaces such as Mars. Among the many engineering challenges for any human presence in the atmosphere of Venus are the corrosive amounts of sulfuric acid in the atmosphere.
  
  NASA's High Altitude Venus Operational Concept is a mission concept that proposed a crewed aerostat design.