Remember all food has to be carried on board as no reloading or shopping is possible. Food also has to be the kind that provides the astronauts all the nutrients they require and must, in addition, look and smell appetizing.

Astronauts spend a great deal of energy  in doing even simple things. For instance, if they try to turn a handle, they turn themselves as well. If they bend down to tie a shoelace, they may end doing somersaults. Such acts have to be done carefully, because of the conditions of weightlessness and astronauts thus spend a lot of extra energy on simple tasks. Also the heart muscles tend to waste away because there is no gravity to battle against and leg muscles weaken too since walking, as it is done on Earth, is not possible.

During the pioneering days of space flight in the 1960's, astronauts had to eat unappetizing food pastes that they squeezed into their mouths from the kind of tubes we use for toothpaste. Today however the meals are much more enjoyable and include scrambled egg, steaks and puddings! In fact there is enough food on board to provide different menus for a span of six days. Food though has to be dehydrated. Dehydration helps to reduce weight and this is of utmost importance in a spacecraft. Some like steak are precooked. Puddings come in cans and fruit is freeze-dried. All these can be re-hydrated. The astronauts have to eat slowly and carefully, for jerky movements can set the food free and keep it floating around the cabin.

However all this does not stop the astronauts' craving for fresh food and one item they miss most of all are salads. Space scientists realized also that carrying enough food for very long journeys was not possible. They would have to grow plants to generate food and so they put their minds to this task.

In 1997, a sealed growth chamber with quick-growing seedlings was placed in the Mir Space Station orbiting the Earth. When astronaut Mike Foale peered into it, he saw that no stems were showing, as they should have. He found what the problem was. The stems were growing downwards and some of the roots were growing upwards. On Earth, stems and roots are guided by gravity, but on the space craft there was almost no gravity and this had the seeds confused. Dr. Musgrave, the scientist, suggested that the plants be given more light and this worked. Once the seedlings had more light, the stems turned up and the roots went down.

Scientists now went on to apply the technology used in latest traffic signals to develop a salad machine which would enable Station crews to grow and harvest their own greens. Edison's bulbs and fluorescent lamps could not be used as they gobbled up electric power and also generated heat. In closed environments heat poses a danger and must be expelled, a difficult task in space-crafts. Scientists, Goin and his team-mates are now experimenting with blue and red lighting diodes. These eliminate wave-lengths found in normal white light, thus reducing the amount of energy required to power plant growth. Less heat is produced though the leaves of the plants take on a black hue due to lack of green light. They grow normally though and taste the same as those raised in white light.

Long human expeditions outside Earth's orbit may be years away, but space-farming efforts are already well under way. Growing plants, scientists agree, is the best way to generate enough food and oxygen to support humans for long periods of time.