Life support system
Encyclopedia
In human spaceflight
, a life support system is a group of devices that allow a human being to survive in space.
US government space agency NASA
,
and private spaceflight
companies
use the term environmental control and life support system or the acronym ECLSS when describing these systems for their human spaceflight
missions. The life support system may supply air, water and food. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are life-critical
, and are designed and constructed using safety engineering
techniques.
per day to perform the standard activities on a space mission, and outputs a similar amount in the form of waste solids, waste liquids, and carbon dioxide
. The mass breakdown of these metabolic parameters is as follows: 0.84 kg of oxygen, 0.62 kg of food, and 3.52 kg of water consumed, converted through the body's physiological processes to 0.11 kg of solid wastes, 3.87 kg of liquid wastes, and 1.00 kg of carbon dioxide produced. These levels can vary due to activity level, specific to mission assignment, but will correlate to the principles of mass balance
. Actual water use during space missions is typically double the specified values mainly due to non-biological use (i.e. personal cleanliness). Additionally, the volume and variety of waste products varies with mission duration to include hair, finger nails, skin flaking, and other biological wastes in missions exceeding one week in length. Other environmental considerations such as radiation, gravity, noise, vibration, and lighting also factor into human physiological response in space, though not with the more immediate effect that the metabolic parameters have.
of each component gas adds to the overall barometric pressure.
By reducing or omitting diluent
s (constituents other than oxygen, e.g., nitrogen and argon) the total pressure can be lowered to a minimum of 21 kPa, the partial pressure of oxygen in the Earth's atmosphere at sea level. This can lighten spacecraft
structures, reduce leaks and simplify the life support system.
However, the elimination of diluent gases substantially increases fire risks, especially in ground operations when for structural reasons the total cabin pressure must exceed the external atmospheric pressure; see Apollo 1. For this reason, most modern crewed spacecraft use conventional air (nitrogen/oxygen) atmospheres and use pure oxygen only in pressure suits during extravehicular activity where acceptable suit flexibility mandates the lowest inflation pressure possible.
s which reintegrate waste material (excrement) back into the system, allowing the nutrients to be taken up by the food crops. The food coming from the crops is then consumed again by the system's users and the cycle continues.
(Lab-on-a-Chip Applications Development) project is working on systems to help detect bacterial and fungal growths in spacecraft used for long-duration spaceflight.
was the first American spacecraft to have an Earth-like atmospheric mixture, 22% and 78%.
For the Space Shuttle, NASA includes in the ECLSS category systems that provide both life support for the crew and environmental control for payloads. The Shuttle Reference Manual contains ECLSS sections on: Crew Compartment Cabin Pressurization, Cabin Air Revitalization, Water Coolant Loop System, Active Thermal Control System, Supply and Waste Water, Waste Collection System, Waste Water Tank, Airlock Support, Extravehicular Mobility Unit
s, Crew Altitude Protection System, and Radioisotope Thermoelectric Generator Cooling and Gaseous Nitrogen Purge for Payloads.
crew module life support system is being designed by Lockheed Martin
in Houston, Texas
.
is called the Kompleks Sredstv Obespecheniya Zhiznideyatelnosti (KSOZh).
Vostok, Voshkod and Soyuz contained air-like mixtures at approx 101kPa (14.7 psi).
is developing a plug and play ECLSS called commercial crew transport-air revitalization system (CCT-ARS) for future spacecraft partially paid for using NASA's Commercial Crew Development (CCDev) money.
is being designed by Bigelow Aerospace
in Las Vegas, Nevada
. The space station
will be constructed of habitable Sundancer
and BA 330 expandable spacecraft modules.
, "human-in-the-loop
testing of the environmental control and life support system (ECLSS)" for Sundancer has begun.
(EVA) systems primarily consist of the traditional space suit, but can also include self-contained individual spacecraft.
models currently in use, the U.S. EMU
and the Russian Orlan, include Primary Life Support System
s (PLSSs) allowing the user to work independently without an umbilical connection from a spacecraft. A space suit must provide life support, either through an umbilical connection or an independent PLSS.
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....
, a life support system is a group of devices that allow a human being to survive in space.
US government space agency NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
,
and private spaceflight
Private spaceflight
Private spaceflight is flight above Earth altitude conducted by and paid for by an entity other than a government. In the early decades of the Space Age, the government space agencies of the Soviet Union and United States pioneered space technology augmented by collaboration with affiliated design...
companies
use the term environmental control and life support system or the acronym ECLSS when describing these systems for their human spaceflight
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....
missions. The life support system may supply air, water and food. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are life-critical
Life-critical system
A life-critical system or safety-critical system is a system whose failure ormalfunction may result in:* death or serious injury to people, or* loss or severe damage to equipment or* environmental harm....
, and are designed and constructed using safety engineering
Safety engineering
Safety engineering is an applied science strongly related to systems engineering / industrial engineering and the subset System Safety Engineering...
techniques.
Human physiological and metabolic needs
A crewmember of typical size requires approximately 5 kg (total) of food, water, and oxygenOxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
per day to perform the standard activities on a space mission, and outputs a similar amount in the form of waste solids, waste liquids, and carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
. The mass breakdown of these metabolic parameters is as follows: 0.84 kg of oxygen, 0.62 kg of food, and 3.52 kg of water consumed, converted through the body's physiological processes to 0.11 kg of solid wastes, 3.87 kg of liquid wastes, and 1.00 kg of carbon dioxide produced. These levels can vary due to activity level, specific to mission assignment, but will correlate to the principles of mass balance
Mass balance
A mass balance is an application of conservation of mass to the analysis of physical systems. By accounting for material entering and leaving a system, mass flows can be identified which might have been unknown, or difficult to measure without this technique...
. Actual water use during space missions is typically double the specified values mainly due to non-biological use (i.e. personal cleanliness). Additionally, the volume and variety of waste products varies with mission duration to include hair, finger nails, skin flaking, and other biological wastes in missions exceeding one week in length. Other environmental considerations such as radiation, gravity, noise, vibration, and lighting also factor into human physiological response in space, though not with the more immediate effect that the metabolic parameters have.
Atmosphere
Space life support systems maintain atmospheres composed, at a minimum, of oxygen, water vapor and carbon dioxide. The partial pressurePartial pressure
In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. The total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture....
of each component gas adds to the overall barometric pressure.
By reducing or omitting diluent
Diluent
A diluent is a diluting agent.Certain fluids are too viscous to be pumped easily or too dense to flow from one particular point to the other. This can be problematic, because it might not be economically feasible to transport such fluids in this state.To ease this restricted movement, diluents...
s (constituents other than oxygen, e.g., nitrogen and argon) the total pressure can be lowered to a minimum of 21 kPa, the partial pressure of oxygen in the Earth's atmosphere at sea level. This can lighten spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
structures, reduce leaks and simplify the life support system.
However, the elimination of diluent gases substantially increases fire risks, especially in ground operations when for structural reasons the total cabin pressure must exceed the external atmospheric pressure; see Apollo 1. For this reason, most modern crewed spacecraft use conventional air (nitrogen/oxygen) atmospheres and use pure oxygen only in pressure suits during extravehicular activity where acceptable suit flexibility mandates the lowest inflation pressure possible.
Water
Water is consumed by crew members through drinking, cleaning activities, EVA thermal control, and emergency uses. It must be stored, used, and reclaimed (from waste water) efficiently since no in-situ sources currently exist for the environments reached in the course of human space exploration.Food
Life support systems often include an indoor plant cultivation system which allows food to be grown within buildings and/or vessels. Often, the system is designed so that it reuses all (otherwise lost) nutrients. This is done, for example, by composting toiletComposting toilet
A composting toilet is a dry toilet that using a predominantly aerobic processing system that treats excreta, typically with no water or small volumes of flush water, via composting or managed aerobic decomposition...
s which reintegrate waste material (excrement) back into the system, allowing the nutrients to be taken up by the food crops. The food coming from the crops is then consumed again by the system's users and the cycle continues.
Microbe detection and control
The NASA LOCADLOCAD
The Lab-on-a-Chip Applications Development element is a set of related lab-on-a-chip projects at NASA. The projects develop integrated lab-on-a-chip products in three areas related to space exploration: Environmental Control and Life Systems Support , Medical Systems, and Remote Exploration...
(Lab-on-a-Chip Applications Development) project is working on systems to help detect bacterial and fungal growths in spacecraft used for long-duration spaceflight.
Gemini, Mercury, & Apollo
American Mercury, Gemini and Apollo spacecraft contained 100% oxygen atmospheres, suitable for short duration missions, to minimize weight and complexity.Space Shuttle
The Space ShuttleSpace Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
was the first American spacecraft to have an Earth-like atmospheric mixture, 22% and 78%.
For the Space Shuttle, NASA includes in the ECLSS category systems that provide both life support for the crew and environmental control for payloads. The Shuttle Reference Manual contains ECLSS sections on: Crew Compartment Cabin Pressurization, Cabin Air Revitalization, Water Coolant Loop System, Active Thermal Control System, Supply and Waste Water, Waste Collection System, Waste Water Tank, Airlock Support, Extravehicular Mobility Unit
Extravehicular Mobility Unit
The Space Shuttle/International Space Station Extravehicular Mobility Unit is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for a Space Shuttle or International Space Station crew member to perform extra-vehicular activity...
s, Crew Altitude Protection System, and Radioisotope Thermoelectric Generator Cooling and Gaseous Nitrogen Purge for Payloads.
Orion crew module
The OrionOrion (spacecraft)
Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
crew module life support system is being designed by Lockheed Martin
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
in Houston, Texas
Houston, Texas
Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...
.
Soyuz
The life support system on the Soyuz spacecraftSoyuz spacecraft
Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...
is called the Kompleks Sredstv Obespecheniya Zhiznideyatelnosti (KSOZh).
Vostok, Voshkod and Soyuz contained air-like mixtures at approx 101kPa (14.7 psi).
Plug and play
The Paragon Space Development CorporationParagon Space Development Corporation
Paragon Space Development Corporation is a company in Tucson, Arizona. It was founded by Jane Poynter and Taber MacCallum. They have supplied hardware to more than 70 spaceflight missions, including ones to the International Space Station and Mir...
is developing a plug and play ECLSS called commercial crew transport-air revitalization system (CCT-ARS) for future spacecraft partially paid for using NASA's Commercial Crew Development (CCDev) money.
Skylab
Because of fire risk and potential physiologic effects, Skylab used 28% Oxygen and 72% Nitrogen.Mir
The Mir and Salyut space stations contained an air-like Oxygen and Nitrogen mixture at approximately sea-level pressures 93.1 kPa (13.5psi) to 129 kPa (18.8 psi) with an Oxygen content of 21% to 40%.Bigelow commercial space station
The life support system for the Bigelow Commercial Space StationBigelow Commercial Space Station
The Bigelow Next-Generation Commercial Space Station is a private orbital space complex currently under development by Bigelow Aerospace. The space station will be constructed of both Sundancer and BA 330 expandable spacecraft modules as well as a central docking node, propulsion, solar arrays,...
is being designed by Bigelow Aerospace
Bigelow Aerospace
Bigelow Aerospace is a North Las Vegas, Nevada space technology startup company that is pioneering work on expandable space station modules. Bigelow Aerospace was founded by Robert Bigelow in 1998...
in Las Vegas, Nevada
Las Vegas, Nevada
Las Vegas is the most populous city in the U.S. state of Nevada and is also the county seat of Clark County, Nevada. Las Vegas is an internationally renowned major resort city for gambling, shopping, and fine dining. The city bills itself as The Entertainment Capital of the World, and is famous...
. The space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...
will be constructed of habitable Sundancer
Sundancer
Sundancer is the proposed third prototype space habitat to be launched by Bigelow Aerospace and the first human-rated expandable module based on TransHab technology acquired from NASA...
and BA 330 expandable spacecraft modules.
, "human-in-the-loop
Human-in-the-Loop
Human-in-the-Loop is defined as a model that requires human interaction. HITL is associated with Virtual Modeling & Simulation in the Live, Virtual, and Constructive taxonomy. HITL models may conform to Human factors requirements as is the case of a Mockup...
testing of the environmental control and life support system (ECLSS)" for Sundancer has begun.
EVA systems
Extra-vehicular activityExtra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
(EVA) systems primarily consist of the traditional space suit, but can also include self-contained individual spacecraft.
Space suits
Both space suitSpace suit
A space suit is a garment worn to keep an astronaut alive in the harsh environment of outer space. Space suits are often worn inside spacecraft as a safety precaution in case of loss of cabin pressure, and are necessary for extra-vehicular activity , work done outside spacecraft...
models currently in use, the U.S. EMU
Extravehicular Mobility Unit
The Space Shuttle/International Space Station Extravehicular Mobility Unit is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for a Space Shuttle or International Space Station crew member to perform extra-vehicular activity...
and the Russian Orlan, include Primary Life Support System
Primary Life Support System
A Primary Life Support System , is a device connected to an astronaut's or cosmonaut's spacesuit, which allows extra-vehicular activity with maximum freedom, independent of a spacecraft's life support system. The PLSS is generally worn like a backpack...
s (PLSSs) allowing the user to work independently without an umbilical connection from a spacecraft. A space suit must provide life support, either through an umbilical connection or an independent PLSS.
See also
- Closed ecological systemClosed ecological systemClosed ecological systems are ecosystems that do not rely on matter exchange with any part outside the system.The term is most often used to describe small manmade ecosystems...
- Environmental control system (aircraft)
- International Conference on Environmental SystemsInternational Conference on Environmental SystemsThe International Conference on Environmental Systems, or ICES , is an annual technical conference focusing on human spaceflight technology and space human factors...
- Primary Life Support SystemPrimary Life Support SystemA Primary Life Support System , is a device connected to an astronaut's or cosmonaut's spacesuit, which allows extra-vehicular activity with maximum freedom, independent of a spacecraft's life support system. The PLSS is generally worn like a backpack...
- Thermal Control System
Further reading
- Eckart, Peter. Spaceflight Life Support and Biospherics. Torrance, CA: Microcosm Press; 1996. ISBN 1881883043.
- Larson, Wiley J. and Pranke, Linda K., eds. Human Spaceflight: Mission Analysis and Design. New York: McGraw Hill; 1999. ISBN 007236811X.
- Reed, Ronald D. and Coulter, Gary R. Physiology of Spaceflight – Chapter 5: 103–132.
- Eckart, Peter and Doll, Susan. Environmental Control and Life Support System (ECLSS) – Chapter 17: 539–572.
- Griffin, Brand N., Spampinato, Phil, and Wilde, Richard C. Extravehicular Activity Systems – Chapter 22: 707–738.
- Wieland, Paul O., Designing for Human Presence in Space: An Introduction to Environmental Control and Life Support Systems. National Aeronautics and Space Administration, NASA Reference Publication RP-1324, 1994
External links
- Environmental Control and Life Support System (NASA-KSC)
- Dedication and Perspiration Builds the Next Generation Life Support System (NASA, Fall 2007)
- Aerospace Biomedical and Life Support Engineering (MIT OpenCourseWare page – Spring 2006)
- Space Advanced Life Support (Purdue course page – Spring 2004)
- Advanced Life support for missions to Mars
- Mars Advanced Life Support
- Mars Life Support Systems
- Publications on Mars Life Support Systems