Life support system

As a life support system technologies or technology combinations are referred to that allow living organisms to survive in environments where their survival is actually not possible. Depending on the life form life-support systems are needed at different locations, based on people, for example, in space or in the deep sea. On Earth, the biosphere is the life support system of living beings dar.

Operation

To survive, different systems are required depending on environmental conditions and use of time. While already the scuba tank and wet suit of a diver can be described as life-support system, more space and energy is necessary for larger, more comfortable and designed for extended stay solutions, enabling either a stationary building or a vehicle ( ship, submarine ) is required.

One of the main functions of life-support systems include the supply of breathing gas, air conditioning and water supply as well as indirectly ( because the supply of the systems) the power supply. Under extreme conditions such as in space or the deep sea and the protection from harmful radiation or the external pressure and the fire detection and fire fighting is to be counted among them. The supply of food is not always calculated directly on the tasks of a life support system, since they are so far provided only by storage available. In the Russian space technology it is with this counted while NASA rather speaks of crew system or crew Habitation system. In future and a long time depending on life-support systems, however, the inclusion of the food supply is necessary. An example of the simulation of such a system within the framework of Biosphere 2 and other similar projects.

For people, this means that per person in a state of rest or light activity per day, about 800 g of oxygen, 2.5 l of water and 700 g of food and, depending on comfort and system 1-5 liters of water for hygienic expenses and a corresponding amount of energy for air conditioning and care must be provided. Depending on labor and working conditions to increase these values ​​. Since the necessary supplies and waste increases with the duration and the number of persons who wins in this context, the regeneration and reclamation in closed circuits of meaning, which describes the transition from open to closed systems. This means that the respective consumables are recovered from waste materials by generally multistage mechanical, physical or chemical processes. Depending on the operating conditions and the available resources but also a direct synthesis (such as the recovery of oxygen and water from sea water on board of submarines ) possible. The corresponding output and accumulated waste materials must be stored, distributed, regenerated or disposed of, including appropriate equipment must be provided in the construction of a life support system. These include, for example, refrigerators, tanks, pipes, pumps, measurement and monitoring technology are necessary.

Breathing gas and air conditioning

To enable people to survive the supply of breathable gas has (ie air) can be ensured. For this, the air must be as free of harmful substances and comply with certain parameters. It is on board the ISS, a total pressure from 97.9 to 102.7 kPa, an oxygen partial pressure of 19.5 to 23.1 kPa, a nitrogen partial pressure of less than 80 kPa, and a carbon dioxide partial pressure of less than 1 kPa is considered acceptable. The air temperature in the ISS is (adjustable) 18.3 to 26.7 ° C. By Air technology, a humidity between 25 and 75% and a constant air movement between 0.05 and 1.0 m / s is secured to prevent microbial growth and mold growth on the one hand and a dry air (risk of spark formation) on the other. Here most conventional air conditioning systems with refrigerants (such as freon or ammonia ) can be used. To dehumidify the air, thereby condensing heat exchangers are used. For carbon sequestration are reusable zeolites or solid amines, used in space suits and lithium hydroxide. The production of oxygen is usually done by the electrolysis of water and partly by recovering from the carbon dioxide via the Sabatier process and subsequent methane pyrolysis. As a backup, or for short-term is also used compressed oxygen or chemical reactions for the delivery of oxygen used. Pollutants are continuously monitored by appropriate measurement methods such as mass spectrometry and gas chromatography and filtered by molecular sieve, activated carbon or lithium hydroxide. In submarines, similar values ​​are valid and there are sometimes even used similar processes.

Water treatment

For the production of drinking water, but also of water for industrial use (such as experiments, fuel, hygiene, ...) are in turn used depending on the requirements of different systems. In submarines, can be obtained from the environment through seawater desalination drinking water directly. In space stations reprocessing systems are used, the gain water from the cabin air by condensation, the amount of waste water (hygiene, experiments, ... ) and the urine of the astronauts. Here come the hot water and condensate appropriate water treatment systems (eg sorption or ion-exchange ) and also preservatives (eg, iodine or silver ) are used. For the reprocessing of urine are special space toilets, suppress only with harsh chemicals such as ozone and sulfuric acid a formation of ammonia ( odor ) and then convert the urine by distillation in hot water.

Crew Systems

For this part of the life support system are all things that are made in direct connection with the work and the well-being of people or creatures. This is especially important for long- term dependency on life-support systems. This includes all things of personal hygiene, food provisioning, preparation and storage, waste treatment, medical care (including sports equipment ), clothing and more. Care must be taken at the food on the shelf life of food and a supply of all the vital substances such as vitamins and minerals. When the food supply in the universe due to the gravity ( risk of inhalation and deposition in filters and devices) is to avoid any form of powdered materials ( sugar, salt, ...) and crumbly foods.

Examples of life-support systems

• Space suit
• Rebreather
• Aquarium
• Pressurized cabin