"Nothing in life is to be feared. It is only to be understood."
-Marie Curie

Life support systems are critical to a Martian colony. Current systems aboard submarines and spacecraft are physicochemical; that is, they supply the crew with the basic necessities with consumables generated by physical and chemical processes. This works for short-duration missions, not for long-duration missions and future colonies. Colonies will need to be self-sufficient and to use what scientists call a bioregenerative life support system.

A bioregenerative life support system will perform all of the basic functions of a life support system based on natural regenerative processes. Such systems incorporate biological components in the synthesis, purification, and regeneration of basic life support consumables. A good example of a bioregenerative system is the Earth. The Earth is a large-scale natural system in which equilibrium is preserved by biological processes.

A closed ecological life support system (CELSS) - would provide basic and continuous life-support requirements such as food, drinking water, and breathable atmosphere by using plants and microbes as the central recycling components. Plants will be utilized in food production, carbon dioxide removal, and oxygen production and, with microbial systems, will support water purification. A regenerative life support system will provide crews with fresh food and the psychological benefits of growing plants. 

The Martian atmosphere is mostly composed of carbon dioxide, which is poisonous to humans. The atmosphere is also extremely thin. Atmospheric pressure on Mars is like being thousands and thousands of feet up in the air on Earth. Here is a little movie of the atmospheric pressure from the Pathfinder mission.

Pressurized domes or cylindrical habitats would contain breathable air. Airlocks would allow suited colonists to go in and out of the environment. Since the air that we breathe out is mostly carbon dioxide, it will need to be eliminated from the atmosphere to keep it fresh just as is in space, on submarines, or in any other closed environment system.

The electrolysis process could provide us with oxygen if we had a source of water and sufficient energy. This process splits up the water into its components, hydrogen and oxygen. The poles of Mars do have water ice in them. Some scientists believe that there may be additional water or ice under the surface of Mars. These hidden reservoirs could be a source for future colonists to use to produce oxygen for breathing. For more information on breathable air for spaceflight, visit this site.

Plants produce oxygen from photosynthesis, which could be used to provide some of the oxygen humans need. The integration of the greenhouse with the living quarters would help to facilitate this process.

The rocks and soil on Mars contain some oxygen. A process for extracting oxygen from rocks and soil on a lunar base is being considered. This process could perhaps also be used on Mars. Factories and laboratories would need to be designed, developed, and integrated to accomplish all of these methods.

An atmosphere revitalization system will need to provide for:

• Carbon dioxide removal and reduction
• Oxygen generation and supply
• Microorganism and contaminant monitoring and control
• Atmosphere storage, control, and supply
• Pressure control
• Temperature and humidity control
• Ventilation

We would not be able to bring enough water with us from Earth that we would need for a colony on Mars. Luckily, the polar caps on Mars have water in them. But melting the polar caps and transporting their water to the settlement would be difficult. If water reservoirs were found underground, then we would have to drill and excavate them. Machines and robots would have to be developed to do either of these things.

Water would also have to be recycled in order to use it most efficiently. Currently NASA has developed advanced recycling techniques so that wastewater recycled using these techniques is purer than the regular water you drink from your tap. Even the moisture in the air you breathe out can be recycled back into drinking water. Human urine and wash water will one day be recycled on the International Space Station as was done in the Advanced Life Support Chamber tests done at the NASA Johnson Space Center. Since a large quantity of water will be needed for a Martian colony, very efficient recycling techniques will also be needed.   Recycling water for human use will be necessary in addition to water used for plants and machines. Laundry and showers (gray water) can be incorporated into hydroponic plant production systems.

Water recovery and management systems would need to include:

• Water storage and distribution
• Water recycling
• Water quality monitoring

The subsequent recovery of water transpired (released) by plants is one means of water purification and recycling that is a natural bioregenerative process. 

Plant growth facilities in greenhouses will be used to provide astronauts with their daily intake of foods. Fortunately plants placed in a controlled environment (like a greenhouse) usually produce much more than field-grown plants.  The reason is that environmental stresses such as wind, weather, insects, animals, and drought are minimized in controlled environments. Engineers working in a controlled environment will have to consider ways to control the temperature, humidity, lighting, water, and nutrients for optimal plant growth.

Click here for a design for greenhouses on Mars.

Click here for some thoughts on animals in space.

Questions to think about:

• How would you go about searching for water under the surface of Mars? If you found it, how would you retrieve it?
• How would you melt and transport ice from the polar ice caps? 
• What farm animals would you take to Mars? Why? 
• Which animals might have a hard time adapting to Martian gravity? Why?

Next... Facilities (pg. 4 of 10)