page_title: Mars habitat
section_title: Air
hierarchical_section_title: Mars habitat / Overview / Air
caption_attribution_description: English: Macro photograph of coca-cola bubbles. Deutsch: Makro-Fotografie von Coca-Cola-Bläschen. Japanese: コカ・コーラの泡のマクロ写真。
context_page_description: A Mars habitat is a place that humans can live in on Mars. Mars habitats must contend with surface conditions that include almost no oxygen in the air, extreme cold, low pressure, and high radiation. Alternatively, the habitat may be placed underground, which helps solve some problems but creates new difficulties.
  One challenge is the extreme cost of building materials for Mars, which by the 2010s was estimated be about US$2 million per brick to the surface of Mars. While the gravity on Mars is lower than that on Earth, there is increased solar radiation, temperature cycles, and the high internal forces needed for pressurized habitats to contain air.
  To contend with these constraints, architects have worked to understand the right balance between in-situ materials and construction, and ex-situ to Mars. For example, one idea is to use the locally available regolith to shield against radiation exposure, and another idea is to use transparent ice to allow non-harmful light to enter the habitat. Mars habitat design can also involve the study of local conditions, including pressures, temperatures, and local materials, especially water.
context_section_description: In creating a habitat for people, some considerations are maintaining the right air temperature, the right air pressure, and the composition of that atmosphere.
  While it is possible for humans to breathe pure oxygen, a pure oxygen atmosphere was implicated in the Apollo 1 fire. As such, Mars habitats may have a need for additional gases. One possibility is to take nitrogen and argon from the atmosphere of Mars; however, they are hard to separate from each other. As a result, a Mars habitat may use 40% argon, 40% nitrogen, and 20% oxygen. See also Argox, for the argon breathing gas mixture used in scuba diving
  A concept to scrub CO
  2 from the breathing air is to use re-usable amine bead carbon dioxide scrubbers. While one carbon dioxide scrubber filters the astronaut's air, the other can vent scrubbed CO
  2 to the Mars atmosphere, once that process is completed another one can be used, and the one that was used can take a break.
   
  One unique structural force that Mars habitats must contend with if pressurized to Earth's atmosphere, is the force of air on the inside walls. This has been estimated at over 2,000 pounds per square foot for a pressurized habitat on the surface of Mars, which is radically increased compared to Earth structures. A closer comparison can be made to crewed high-altitude aircraft, which must withstand forces of 1,100 to 1,400 pounds per square foot when at altitude.
  At about 150 thousand feet of altitude (28 miles (45 km))  on Earth,  the atmospheric pressure starts to be equivalent to the surface of Mars.
  See also Effects of high altitude on humans
  Temperature
  One of the challenges for a Mars habitat is for it to maintain suitable temperatures in the right places in a habitat. Things like electronics and lights generate heat that rises in the air, even as there are extreme temperature fluctuation outside. There can be large temperature swings on Mars, for example at the equator it may reach  70 degrees F (20 degrees C) in the daytime but then go down to minus 100 degrees F (−73 C) at night.
  Examples of Mars surface temperatures:
  Average −80 degrees Fahrenheit (−60 degrees Celsius).
  Polar locations in winter  −195 degrees F (−125 degrees C).
  Equator in summer daytime High 70 degrees F (20 degrees C)
caption: Bubbles of gas in a soft drink (soda pop)
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