When humans establish permanent bases on the Lunar surface or travel to Mars for exploration, they will continue to need food, water, and air. For long term missions, it will not be economically feasible to resupply these life support elements from Earth, and it will be impossible to carry all the needed supplies on a spacecraft. Humans will need to develop systems to produce food, purify their water supply, and create oxygen from the carbon dioxide they expel.

Biological systems utilize plants and microorganisms to perform these life support tasks in a process termed bioregeneration. A life support system that would perform these regenerative functions, whether strictly by biological means or by a combination of biological and physico-chemical methods, has been called a Bioregenerative Life Support System (BLSS) or a Controlled Ecological Life Support System (CELSS). The components of a closed life support system must be highly interdependent. In such a closed system, humans take in oxygen, food and water, and expel carbon dioxide and organic waste. Plants utilize carbon dioxide, produce food, release oxygen, and purify water. Inedible plant material and human waste are degraded by microorganisms to recycle nutrients for plants in a process termed resource recovery.

Teaching Goals:

• Outline human total life-support requirements and discuss the advantages/disadvantages of robotic missions (Viking) versus human missions.
• Review the adverse environment of space (e.g., vacuum, temperature, mobility, food and water, waste products) pertinent to living in space and EVA.
• Discuss the nature and feasibility of open, semi-closed, and closed life support systems (e.g., capacity, stability, need for resupply) and relate this to current or planned systems.
• Analyze studies conducted in Biosphere 2 or other closed environmental systems as they may relate to long-term space flight or colonization.