Life-support system facts for kids

This page is about equipment used in extreme environments. For emergency medical techniques, see Life support.

Apollo's portable life support system, used by astronauts

A life-support system is special equipment that helps living things survive in places or situations where they normally couldn't. It's often used for humans in tough environments like outer space or deep underwater. It's also used in hospitals when someone is very sick and needs help to stay alive.

In human spaceflight, a life-support system is a set of devices that lets an astronaut live in space. Space agencies like NASA call these "environmental control and life-support systems," or ECLSS. These systems provide air, water, and food. They also keep the right body temperature and pressure. They even handle waste products. Sometimes, they protect against dangers like radiation. These systems are super important for safety.

For underwater diving, breathing gear is life support. A saturation diving system is also a life-support system. People who run them are called life support technicians. This idea also applies to submarines and special atmospheric diving suits. These systems make sure the air is safe to breathe and keep people safe from outside pressure and temperature.

In medicine, life-support systems include heart-lung machines, medical ventilators, and dialysis equipment. These machines help the body's vital organs work when they can't do it alone.

What Humans Need to Survive in Space

Astronauts need about 5 kilograms (11 pounds) of food, water, and oxygen each day. They also produce waste. For example, they use about 0.84 kg (1.85 lbs) of oxygen and 3.54 kg (7.8 lbs) of water. They produce about 1 kg (2.2 lbs) of carbon dioxide. These amounts can change based on what the astronaut is doing. Water use is often higher because of things like showering.

Other things like radiation, noise, and light also affect astronauts. But getting enough air, water, and food is the most important for immediate survival.

Breathing in Space

Life-support systems in space must provide oxygen, water vapor, and remove carbon dioxide. The amount of each gas adds up to the total air pressure.

Early spacecraft sometimes used pure oxygen. This made fire a bigger risk, especially on the ground. Also, too much oxygen can be bad for you. Today, most spacecraft use air like we breathe on Earth. This is a mix of nitrogen and oxygen. Astronauts only use pure oxygen in their pressure suits for spacewalks. This is because pure oxygen allows the suit to be at a lower pressure, making it easier to move.

Water in Space

Astronauts need water for drinking, cleaning, and cooling their spacesuits. Water must be stored, used, and cleaned very carefully. This is because there are no easy ways to get new water in space. Future missions to the Moon or Mars might find water from ice.

Food for Astronauts

So far, all space missions have carried all their food from Earth. Future life-support systems might include growing plants in space. This would also help recycle water and make oxygen. However, no such system has been used in space yet.

A plant system could reuse most waste nutrients. For example, special toilets could turn waste into plant food. The plants would then grow food for the astronauts, and the cycle would continue. But setting up such a system needs a lot of space and planning.

Dealing with Gravity in Space

Long space missions can make astronauts feel sick and lose bone and muscle. This is because there is no gravity in space. To help with this, scientists are looking at ways to create "artificial gravity."

One way is to have the spacecraft constantly push forward. If it pushes with the right amount of force, the crew would feel a pull towards the back of the ship. This would feel like normal Earth gravity.

Another way is to spin the spacecraft. If a part of the ship is shaped like a big cylinder, spinning it can create a force that feels like gravity. This is called centrifugal force. However, this force would be different depending on where you are in the spinning part. Also, moving around in a spinning ship can feel strange because of something called the Coriolis force.

Life Support on Spacecraft

Early Spacecraft

American Mercury, Gemini, and Apollo spacecraft used 100% oxygen inside. This was good for short trips because it made the systems lighter and simpler.

The Space Shuttle's System

The Space Shuttle was the first American spacecraft to have an atmosphere like Earth's. It used 22% oxygen and 78% nitrogen. For the Space Shuttle, NASA included many systems under ECLSS. These systems provided air, controlled temperature, managed water, and handled waste. They also supported spacewalks.

Soyuz Spacecraft

The Soyuz spacecraft from Russia also used an air-like mix of nitrogen and oxygen. Its system kept the air pressure similar to sea level on Earth. It used special cylinders to absorb carbon dioxide and water. These cylinders also helped make new oxygen.

Modern Systems

Companies are now developing new "plug and play" life-support systems. One example is the "commercial crew transport-air revitalization system" (CCT-ARS). This system can control air temperature, remove humidity, take out carbon dioxide, and clean the air. It also helps recover the air after a fire.

Life Support on Space Stations

Space stations need technology that lets humans live in space for a long time. This includes systems to filter human waste and produce fresh air.

Skylab

The American Skylab space station used a mix of 72% oxygen and 28% nitrogen. The total pressure inside was lower than on Earth.

Salyut and Mir

The Russian Salyut and Mir space stations used an oxygen and nitrogen mix. The pressure was similar to sea level on Earth. The oxygen content could be between 21% and 40%.

Bigelow Commercial Space Station

Bigelow Aerospace is designing the life-support system for its future commercial space station. This station will use inflatable modules. They have already started testing the environmental control and life-support system for these modules.

Natural Life Support Systems

Scientists have tested natural life-support systems like Biosphere 2 in Arizona. These systems are also called closed ecological systems. They use sunlight as their main energy source. This means they don't need constant supplies from Earth. Natural systems are very efficient because different parts work together. They also create a more natural environment for humans, which is good for long stays in space.

Life Support Underwater

Underwater habitats and special diving facilities provide life support for divers for days or weeks. Divers in these places cannot return to the surface right away. They need weeks to safely adjust to normal pressure.

The life-support system for these facilities provides breathing gas and other services. It includes:

Machines to compress, mix, and store gases.
Systems to control temperature and humidity inside the chambers.
Equipment for monitoring, control, and communication.
Fire safety systems.
Toilets and cleaning systems.

Underwater habitats keep the same pressure inside as the water outside. This lets divers easily go in and out. However, divers in surface systems are moved to their working depth in a special closed diving bell.

The life-support system for the diving bell provides breathing gas and monitors the divers. A thick cable, called an umbilical, connects the bell to the surface. This cable carries gas, power, and communication lines. Smaller cables connect the divers to the bell.

The main life-support system keeps the living area safe and comfortable. It monitors temperature, humidity, air quality, and sanitation.

Experimental Life-Support Systems

MELiSSA

The Micro-Ecological Life Support System Alternative (MELiSSA) is a project led by the European Space Agency. It uses tiny organisms and plants to create an artificial ecosystem. The goal is to understand how these systems work. This will help create future life-support systems for long space missions.

CyBLiSS

CyBLiSS stands for "Cyanobacterium-Based Life Support Systems." This idea uses cyanobacteria (a type of bacteria) to turn resources found on Mars into useful products. It also creates materials for other living systems. The goal is to make future human bases on Mars as independent from Earth as possible. This would lower mission costs and make them safer. CyBLiSS could connect other life-support systems to materials found on Mars, making them sustainable.