THE WATER OF THE ASTRONAUTS

Have you ever tried to put packages of 5 litres of mineral water in the valise porter of your small car? Let us say that we tried to put 10 units of these. Actually it is a bit complicated to introduce some voluminous object additional. We suppose that we introduced 50 litres of water. Then, this amount is the equivalent to the third part of the average daily consumption of a Spanish person.

If we consider an average family of four members, we would need to introduce about 640 litres of water in our car, equivalent to 128 packages of 5 litres to supply to them during a day. It's a bit complicated, isn't it? Then, still more complicated it turns out to provide to water to the four members in the Space International Station along several months in orbit. It's important to remember that the space in these boats is extremely reduced, so it isn't able to stock a great volume of water.

The NASA has a program, which is called ECLSS, to optimize generation of energy provisions, clean water and breathable air in good conditions of suitable temperature and humidity, during 24 hours/day, 7 days for week and in an indefinite way.

If any of the habitants of the Station is a little apprehensive he would have to avoid to think about the water that he is going to drink. The main potable water source comes from the breathing of the crew members. When they exhale the air of the breathing they lose water that is gotten up to the environmental humidity. This one humidity of the cabin of the Station is condensed to become on the water supplies.

It is obvious that the transport of water from the Earth is too expensive and that is necessary to recycle. But before being able to recycle water, it must exist another to start off. The NASA has developed a system of water purification that uses residual water coming from the urine, the buccal washing, the hygiene of the hands and condensation of the environmental humidity. It can be eschatological, but without this one process would be necessary to transport about 18.000 kg of water from the Earth every year to be able to supply to a crew of four members.

The process consists on three stages. First of all, the water flow crosses filter in order to retain particles of greater size. Later, it crosses beds that they have in its surface substances able to retain different organic compounds e inorganic ones and the last stage consists on passing the water to treat to the interior of a catalytic oxidation reactor where the virus and bacteria are destroyed. It can seem strange, but the water which results of this equipment of purification has better quality than the one that leaves by the faucet of any city of an industrialized country.