Space Stations

Space Station, any facility that enables humans to live in space for long periods of time. Space stations are used as laboratories where scientific and engineering experiments are conducted and as servicing centers where spacecraft can be repaired, upgraded, or even constructed. Space stations are expected to one day act as spaceports where spacecraft can pick up and deliver people, cargo, and fuel on the way to or returning from distant destinations, such as Mars.

Space stations require regular visits by spacecraft from Earth to deliver supplies. Some supplies are needed to help the space station complete its mission and may include new experiments, satellites, or fuel for rockets. Other supplies, such as replacements for worn out or broken parts, enable the station to continue operating.

The space station’s life-support system, the technology that provides a comfortable internal environment in the space station, must be supplied with oxygen, water, and food. These supplies are ferried from Earth on a regular basis. An average human needs about 630,000 cu cm (about 38,000 cu in) of oxygen, about 2 l (about 0.5 gallons) of water, and about 500 g (about 1 lb) of dry food each day. Together, the oxygen, water, and food for a single person for one day has a mass of about 3.4 kg (about 7.5 lb). The life-support system must also remove the carbon dioxide and water that humans breath out, and remove the fluid and solid waste they produce.

Simple space stations with open-loop systems need all of the food, water, and oxygen delivered regularly and they discard all of the waste. More advanced, closed-loop space stations recover oxygen from carbon dioxide and recycle the water. This reduces the supplies that must be brought from Earth to keep the crew alive.