Background Information

Survival on long duration space missions depends a great deal upon the explorers having a nutritious diet. Not only are sufficient calories required for the work that they will be expected to carry out, but the diet must also be rich in essential vitamins and minerals in order to maintain good health for the duration.

A fresh and varied diet is not only essential for good physical health, but it is important for the maintenance of good psychological health as well.

From a purely technical point of view, it will be absolutely essential to grow at least some of the food required for a long duration space mission, since the mass of seeds is vastly less than the mass of the food that they will produce.

The prohibitively large mass of several years' worth of food makes a mission of long duration much more expensive unless food can be grown at the destination.

Of course, a major fraction of most food is water, and for this reason it will be important to find a source of water on Mars if we are going to grow plants as a source of food when we get there.

Greenhouse

Figure 1: On Mars the thin atmosphere and very cold temperatures will require that greenhouses be constructed in order for plants to survive, mature, and produce vegetables or fruit.

Once astronauts land on Mars they will be obliged to remain on Mars for a significant period of time (15-18 months) in order for a return launch window to open up. (This has to do with the relative alignment of the Earth and Mars at the time of launch).

Small, light-weight greenhouses will be required. How big should they be? What seeds should be taken to Mars? Should some of the seeds be germinated in space prior to landing on Mars to get a head start on their growth? If yes... which seeds and how far ahead of the landing should the germination start? These and other similar questions are the focus of this investigation.

Low pressure greenhouses

Figure 2: Low pressure greenhouses on the surface of Mars may be used to grow food for long term visits to the planet. The transparent coverings will have to keep the crops both warm and protected from ultraviolet radiation.

Notes

The activities in this module are designed to focus on the biophysics and biochemistry of plant growth and human nutrition.

Activity 1 deals with the water content of fruits and vegetables.

Activity 2 deals more specifically with human nutritional requirements and how these requirements can be satisfied by a wide range of well-chosen fruits and vegetables.

The Extension Activities are designed to expand the student's knowledge over a broad range of related topics including plant physiology and human nutrition and could be used as the basis of independent study units in science.