The Potential for Reducing the Weight of a Martian Greenhouse 2001-01-2360
Use of the local resources on Mars could reduce the cost of life support significantly. Theoretically, Closed Ecological Systems (CES) isolated from surroundings and functioning on the basis of a closed cycle of matter transformation are the most reliable systems for life support in open space or on the surface of non-terrestrial bodies such as the Moon or Mars. But these systems require a relatively high initial mass (which is a critical factor in space flight) in comparison to supply-based systems. In addition CESs are a useful scientific abstraction though they have never been reached in reality.
To minimize the cost of life support on Mars, we need to find scenarios and technologies such as a Martian Greenhouse (MG) which are based on use of the planet’s indigenous sources of energy and materials (natural illumination, carbon dioxide, water, nutrient elements for plants in the planetary soil). Our initial analysis shows that such approaches are possible and cost effective. The mass of supplies associated with the biological part of life support in a MG could probably be reduced to a few percent compared to a completely closed system for Martian conditions. This reduction does not apply to the physical shell and crop support equipment, which will remain practically the same for different kinds of scenarios and systems and determined mainly the physical conditions on Mars (gravitation, atmosphere, radiation, etc.).
Realization of these so called resource oriented scenarios requires development of technologies for MG functioning such as collection of carbon dioxide, separation and concentration of oxygen, accumulation of natural water, treatment of the soil, design of enclosures, light utilization, automation/ control, and others. We also need to investigate the physiological limits of higher plants at low temperatures, illumination, atmospheric pressure, humidity and probably other conditions. There will be costs associated with using Martian resources. However, existing work e.g. at NASA ARC suggests that the benefits will greatly exceed the costs.
In conclusion the most effective way to reduce the mass of the MG is through a balanced approach including MG engineering design, limits of plant physiology, greenhouse and environment interaction and In Situ Resources Utilization (ISRU).