NASA-STD-3001 Technical Brief

Relevant Technical 

Requirements

Environmental Control 

& Life Support System 

(ECLSS): Human-Centered 

Approach

OCHMO-TB-002

Rev B

NASA-STD-3001 Volume 2, Rev D

[V2 4015] Aerobic Capacity

[V2 6001] Trend Analysis of Environmental 

and Suit Data

[V2 6002] Inert Diluent Gas

[V2 6003] O2 Partial Pressure Range for Crew 

Exposure

[V2 6004] Nominal Vehicle/Habitat Carbon 

Dioxide Levels

[V2 6006] Total Pressure Tolerance Range for 

Indefinite Crew Exposure

[V2 6007] Rate of Pressure Change

[V2 6150] Barotrauma Prevention

[V2 6008] Decompression Sickness (DCS) Risk 

Identification

[V2 6009] Decompression Sickness 

Treatment Capability

[V2 6011] Post Landing Relative Humidity 

(RH)

[V2 6012] Crew Health Environmental Limits

[V2 6013] Crew Performance Environmental 

Zone

[V2 6014] Crewmember Heat Storage

[V2 6151] Temperature Selectability

[V2 6152] Temperature Adjustability

[V2 7041] Environmental Control During 

Exercise

[V2 6017] Atmospheric Control

[V2 6020] Atmospheric Data Recording

[V2 6021] Atmospheric Data Displaying

[V2 6022] Atmospheric Monitoring and 

Alerting Parameters

[V2 6023] Trace Constituent Monitoring and 

Alerting

Executive Summary

Humans living and working in space contend with 

a hostile/closed environment that must be 

monitored and controlled to keep the 

crewmembers safe and able to perform mission 

objectives. NASA-STD-3001 provides technical 

requirements that address the key aspects of the 

human physiological system that must be 

accounted for by programs employing humanrated systems. Compliance with requirements 

may be ensured with the tailored implementation 

of an Environmental Control and Life Support 

System (ECLSS). The ECLSS provides clean air and 

water to crew in a manned spacecraft through 

artificial means. The ECLSS manages air and 

water quality, waste, atmospheric parameters, 

and emergency response systems.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Relevant Technical 

Requirements

Executive Summary (continued)

2

NASA-STD-3001 Volume 2, Rev D

[V2 6024] Combustion Monitoring and 

Alerting

[V2 6025] Contamination Monitoring and 

Alerting

[V2 6153] Celestial Dust Monitoring and 

Alerting

[V2 6107] Nominal Vehicle/Habitat 

Atmospheric Ventilation

[V2 6108] Off-Nominal Vehicle/Habitat 

Atmospheric Ventilation

[V2 6050] Atmosphere Contamination Limit

[V2 6052] Particulate Matter

[V2 6053] Lunar Dust Contamination

[V2 6059] Microbial Air Contamination

[V2 6026] Potable Water Quality

[V2 6051] Water Contamination Control

[V2 6046] Water Quality Monitoring and 

Alerting

[V2 6109] Water Quantity

[V2 6110] Water Temperature

[V2 6039] Potable Water Dispensing Rate

[V2 6040] Potable Water Dispensing 

Increments

[V2 6047] Toxic Hazard Level Three

[V2 6048] Toxic Hazard Level Four

[V2 6049] Chemical Decomposition

[V2 6060] Biological Payloads

[V2 6061] Environment Cross-Contamination

[V2 6063] Contamination Cleanup

[V2 7020] Body Waste Management 

Capability

[V2 7025] Body Waste Containment

[V2 7110] Food and Impacts to 

Environmental Systems

[V2 7115] Medical Treatment, Personal 

Supplies, and Impacts to Environmental 

Systems

[V2 9059] Fire Detecting, Warning, and 

Extinguishing

11/14/2023

Rev B

Related Technical Briefs

OCHMO-TB-004 Carbon Dioxide (CO2)

OCHMO-TB-037 Decompression Sickness (DCS) 

OCHMO-TB-015 Spaceflight Toxicology

OCHMO-TB-042 Waste Management

OCHMO-TB-027 Water

OCHMO-TB-008 Fire Protection

OCHMO-TB-030 Bone Loss

OCHMO-TB-003 Habitable Atmosphere

Houston We Have a Podcast

John Lewis, Orion ECLS (Environmental 

Control and Life Support) system manager, 

discusses how the Orion spacecraft will keep 

the crew inside comfortable – and more 

importantly, alive – during a mission into 

deep space.

Ep79: Livable Space | NASA
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Overview

11/14/2023

Rev B 3

Environmental Control and Life Support Subsystem Diagram 

[V2 6002] Inert Diluent Gas

[V2 6003] O2 Partial Pressure 

Range for Crew Exposure

[V2 6006] Total Pressure 

Tolerance Range for Indefinite 

Crew Exposure

[V2 6025] 

Contamination 

Monitoring and Alerting

[V2 6050] Atmosphere 

Contamination Limit

[V2 6024] Combustion 

Monitoring and Alerting

[V2 9059] Fire 

Detecting, Warning, 

and Extinguishing

[V2 6012] Crew Health Environmental Limits

[V2 6013] Crew Performance Environmental 

Zone

[V2 6107] Nominal Vehicle/Habitat 

Atmospheric Ventilation

[V2 6004] 

Nominal 

Vehicle/Habitat 

Carbon Dioxide 

Levels

[V2 6026] Potable Water Quality

[V2 6051] Water Contamination Control

[V2 6109] Water Quantity

[V2 6110] Water Temperature

[V2 6039] Potable Water Dispensing Rate

[V2 6040] Potable Water Dispensing 

Increments

[V2 7020] Body Waste 

Management 

Capability

[V2 7025] Body Waste 

Containment
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Human Body Inputs and Outputs

The primary functions of the ECLSS is to provide a healthy, productive living and working environment that 

can maintain the health of the crew while they live in harsh conditions that would be otherwise 

uninhabitable due to changes in pressure, temperature, atmosphere, as well as logistics to provide 

breathable air and water. 

Background

11/14/2023

Rev B 4

Outputs

Fecal & Urine

Feces: max average of 2 

events of 1.1lb/event per 

crewmember per day [V2 

7102] 

Urine: max average of 7 

events of 1L/event per 

crewmember per day [V2 

7102] 

Liquid

3.870kg/day per 

crewmember Respiration 

and Perspiration 

(combined with urine)

Respiration

Average 1 hour CO2 partial 

pressure (ppCO2) <3 

mmHg [V2 6004]

Environmental Regulation

[V2 6012] Crew Health 

Environmental Limits

Operating Limit: 18°C/75% 

humidity to 27°C/25% 

humidity

[V2 6013] Crew 

Performance 

Environmental Zone

Operating Limit: 20°C -

25°C and 30-60% humidity

Inputs

Food & Nutrition

Average 3,035 kcal/day per 

crewmember [V2 7003]

Water

Minimum 2.5 L/day per 

crewmember [V2 6109] 

Gas

>30% diluent gas [V2 

6002]

145-155 O2 partial 

pressure (mmHG) 

normoxia target range [V2 

6003]

In addition to these guidelines, 

special considerations must be given 

to the following:

• Increased O2 consumption, and 

increased CO2, perspiration, and 

metabolic heat output during crew 

exercise time [V2 7041].

• Need for extra calories and 

potable water during EVAs [V2 

7004] & [V2 11030].
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

Pressure Control System (PCS) Humans receive essential oxygen through respiration, where oxygen (O2) is 

taken into the lungs and absorbed in the body, allowing all critical body systems to function. In addition to 

absorbing O2, the body releases carbon dioxide (CO2) and gaseous nitrogen (N2). The body requires a 

stable O2 partial pressure in order to maintain adequate oxygen balance. 

11/14/2023

Rev B 5

PCS functions include:

• Monitor O2, N2, and total pressure

• Maintain O2/N2 environment pressurized to ranges that are habitable for crew and functional for 

the cabin air-cooled equipment

• Supply N2 to pressurize the supply and wastewater tanks

• Supply breathing gas directly to the Launch and Entry Suit (LES) helmets

• Capable of rapid depressurization response if needed

NASA-STD-3001 Technical Requirements for PCS

3001 Technical Requirement ECLSS Function

[V2 6002] Inert Diluent Gas Maintain at least 30% diluent gas in the cabin 

atmosphere to mitigate clinically significant absorption 

atelectasis.

[V2 6003] O2 Partial Pressure Range for Crew 

Exposure

Maintain inspired oxygen partial pressure (PIO2) within 

the given pressure exposure ranges to prevent hypoxia 

or hyperoxia.

[V2 6006] Total Pressure Tolerance Range for 

Indefinite Crew Exposure

Maintain the pressure to which the crew is exposed 

between 34.5 kPa < pressure ≤ 103 kPa (5 psia < 

pressure ≤ 15.0 psia) for indefinite exposure without 

measureable impairments to health or performance.

[V2 6007] Rate of Pressure Change For pressure changes >1.0 psi, limit the rate of change 

of total internal vehicle pressure to 13.5 psi/min or 

less to prevent injury to crewmembers’ ears and lungs 

during depressurization and repressurization. 

[V2 6150] Barotrauma Prevention Give crew the ability during a commanded pressure 

change to pause the system within 1 psi of the 

command being issued and the ability to increase or 

decrease pressure as needed to avoid discomfort and 

barotrauma. 

[V2 6009] Decompression Sickness Treatment 

Capability

The system is capable of providing DCS treatment.

Reference OCHMO-TB-037 Decompression Sickness (DCS) and OCHMO-TB-003 Habitable Atmosphere 

for additional information.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

The ECLSS system functions to maintain homeostasis of the crewmembers by managing the atmospheric 

air composition and pressure make-up. In combination with other requirements that control the cabin 

atmosphere (i.e., CO2, ventilation, temperature/humidity, etc.), these ECLSS functions maintain crew 

health, safety, and overall performance. 

11/14/2023

Rev B 6

Diluent Gas

Nominally, the cabin atmosphere 

must contain at least 30% diluent 

gas. Measurable oxygen 

absorption atelectasis occurs with 

fractions of oxygen above 50%. A 

diluent gas is required to prevent 

excessive levels of oxygen 

absorption atelectasis during 

prolonged exposures, in addition 

to reducing the 

ignition/flammability threshold.

Oxygen

For all systems, the range of 

ambient dry-gas ppO2 is to be 

considered in the context of 

PI

O2. Normoxia target range is 

145-155 mmHg. This prevents 

the occurrence of hypoxia or 

hyperoxia.

Pressure

Total pressure is maintained 

between 34.5 kPa < pressure ≤ 

103 kPa (5 psia < pressure ≤ 15.0 

psia). During certain spacesuit 

operations, the crew may be 

exposed to pressure above or 

below this range for limited 

periods of time. Total pressure 

and rates of pressure change are 

maintained to prevent 

decompression sickness and 

barotrauma symptomatology.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 7

Air Revitalization System (ARS) is responsible for air quality during crewed missions including:

•Control of temperature and humidity

•Air circulation and ventilation

•Removal of CO2 and trace contaminants

•All associated monitoring

NASA-STD-3001 Technical Requirements ARS

3001 Technical Requirement ECLSS Function

[V2 6001] Trend Analysis of Environmental and Suit 

Data

System monitors environmental data to perform temporal 

trend analyses.

[V2 6004] Nominal Vehicle/Habitat Carbon Dioxide 

Levels

Limits average one-hour CO2 partial pressure (ppCO2) in the 

habitable volume to no more than 3 mmHg.

[V2 6012] Crew Health Environmental Limits Maintain cabin humidity and temperature within the 

defined operating limits to protect for crew health.

[V2 6013] Crew Performance Environmental Zone Enable the system to reach defined cabin humidity and 

temperature levels to support crew comfort and 

performance.

[V2 6107] Nominal Vehicle/Habitat Atmospheric 

Ventilation

Maintains ventilation rate within atmosphere to provide 

adequate circulation to prevent CO2 and thermal pockets 

from forming.

[V2 6108] Off-Nominal Vehicle/Habitat 

Atmospheric Ventilation

Controls for ppO2, ppCO2 and relative humidity during offnominal operations.

[V2 6021] Atmospheric Data Displaying System displays real-time values for pressure, humidity, 

temperature, ppO2, and ppCO2.

[V2 6022] Atmospheric Monitoring and Alerting 

Parameters

System alerts the crew locally and remotely when 

atmospheric parameters are outside safe limits (including 

pressure, humidity, temperature, ppO2, and ppCO2).

[V2 6024] Combustion Monitoring and Alerting System monitors in real-time for toxic atmosphere 

components that would result from pre-combustion and 

combustion events.

[V2 6025] Contamination Monitoring and Alerting System monitors and displays atmospheric compound 

levels.

[V2 6050] Atmosphere Contamination Limit Limits gaseous pollutant accumulation in the habitable 

atmosphere to below chemical concentration limits 

specified in JSC-20584, Spacecraft Maximum Allowable 

Concentrations for Airborne Contaminants (SMACs).
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 8

Temperature and Humidity

NASA-STD-3001 levies two technical requirements related to the atmospheric environment: 

• [V2 6012] provides environmental parameters that keeps the internal habitat at safe levels of temperature 

and humidity for protection of crew health. 18°C - 27°C and 25 - 75% humidity 

• [V2 6013] provides environmental parameters that take into consideration crew performance, specifying 

temperature and humidity limits in which humans can achieve thermal comfort and not have their 

performance of routine activities affected by thermal stress. 20°C - 25°C and 30 - 60% humidity

Air Circulation and Ventilation

Fans and appropriate ventilation are important to mix atmospheric gases and decrease risk of pockets or 

overexposure to any gas. Due to lack of natural convection in microgravity, spacecrafts may develop areas with 

low atmospheric circulation, which could result in a localized area of increased CO2. Some special 

considerations for the design of ventilation systems include:

• Exercise station – Exercise areas need increased airflow to facilitate heat transfer and relieve sweat 

accumulation.

• Sleeping station – Individually adjustable airflow controls for comfort and prevention of CO2 pockets.

• Eating station – Airflow should not blow loose morsels of food away from crewmembers.

• Maintenance areas – Crewmembers may perform maintenance behind a panel in an area not part of the 

nominal habitable volume and therefore does not have ventilation. 

Due to individual variability among crewmembers and the likelihood of different crewmembers 

performing different tasks at different metabolic rates, it is necessary to have the capability to 

change temperature set points, adjust localized air flow, and/or have various clothing options 

available to achieve thermal comfort for all crew. 

Interaction of breath dynamics and the personalized ventilation (PV) diffuser for case SM2 (frontal PV 

solution) in median plane at end of exhalation (left chart) and end of inhalation (right chart)

From: Georgescu et al. (2021) Personalized ventilation solutions for reducing CO2 levels in the crew 

quarters of the International Space Station

Findings: A personalized ventilation diffuser in close proximity to the breathing zone reduces inhaled CO2

Reference the NASA 

HIDH for additional 

information on air 

circulation and 

ventilation.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 9

Removal of CO2 and Trace Contaminants

Humans on spacecraft vehicles are the main contributors to atmospheric CO2 levels. Crewmembers inhale the 

ECLSS-provided safe breathable air and exhale CO2, which is removed from the atmosphere by a carbon dioxide 

removal process designed to maintain the cabin atmosphere within safe ranges. If CO2 levels become too 

elevated, the crewmembers may begin to experience adverse effects (see graphic below and CO2 technical 

brief for additional information). 

In addition to the removal of CO2 from the atmosphere, toxic 

chemicals must also be monitored for and removed via the ECLSS. 

The crew may be exposed to chemicals from a variety of sources 

including compounds used in the system, payload chemicals, offgassed products, batteries, products of corrosion, external 

contaminants, hardware failures and repairs, and thermal 

degradation of electronic components. NASA toxicologists establish 

guidelines for safe and acceptable levels of individual chemical 

contaminants in spacecraft air (SMACs) to provide guidance on 

allowable chemical exposures during nominal operations and 

emergency situations. 

Atmospheric Monitoring and Alerting

Air monitoring gives the crew and ground support personnel access to important data regarding the 

atmospheric composition of the spacecraft breathable atmosphere. This in turn provides the capability of 

automatic alerts or alarms when levels are outside of the required ranges set by SMACs so that crew may 

respond appropriately Some targeted monitoring systems of the ECLSS includes: 

• Combustion Product Monitor (CPM) 

• Carbon dioxide monitor (CDM)

• Air quality monitor (AQM)

Portable breathing apparatus

Reference OCHMOTB-004 Carbon 

Dioxide (CO2) for 

additional 

information.

Reference OCHMO-TB-015 Spaceflight 

Toxicology for additional information.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 10

ECLSS Adaptation – Exercise and 

Nutrition Example

The ECLSS must be able to adapt to 

constantly changing atmospheric 

demands created by changes in crew 

number and composition as well as 

changes in crew activity. During 

exercise, crewmembers increase O2

consumption and CO2 output. The 

ECLSS must be designed to handle the 

increased need for oxygen and CO2

scrubbing during exercise times. The 

O2 and CO2 levels are also affected by 

changes in diet makeup (i.e., amount

of calories, fat, and carbohydrates 

consumed). To reduce O2

consumption, activity level must be 

reduced. To reduce CO2 production, 

reduce activity and the Respiratory 

Quotient (RQ) by modifying the diet.

O2 Variables: 5ml/kg/min (resting 

energy expenditure). 75 kg average 

person weight. 120 minutes of 

exercise (at 65% average VO2 max= 

45ml/kg/min). 

For example crew of 7 astronauts:

a. Resting oxygen consumption -

0.771 kg/person/day

b. Oxygen consumption during 

exercise - additional 0.376 

kg/person/exercise session 

c. Daily oxygen consumption (with 

exercise) - 1.083 kg/person/day

d. Total Oxygen consumption with 

no exercise - 5.397 kg O2/day

e. Total Oxygen consumption with 

exercise - 7.581 kg O2/day

f. Need additional 2.184 kg O2/day 

with exercise activity

CO2 Variables: 20 Kcal/Kg/diet composed of 40% fat and 20% 

carbohydrate diet to create an RQ of 0.85.

a. Assuming a mixed diet and RQ of 0.85, crew weight of 75 kg, the 

Volume of CO2 produced assuming a 2,000 calorie diet is 350 

Liters/per person/per day. 

b. Assuming a mixed diet and RQ of 0.85, crew weight of 75 kg, the 

Volume of CO2 produced assuming a 1,500 calorie diet is 262 

Liters/per person/per day. 

c. Assuming a mixed diet and RQ of 0.85, crew weight of 75 kg, the 

Volume of CO2 produced assuming a 1,000 calorie diet is 175 

Liters/per person/per day.

O2 Consumption Reduction of 10%

CO2 Production Reduction of 20%
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 11

Water Management

Astronauts need approximately 2.5 L of potable water for hydration per crewmember per day. Additional 

potable water is allotted for hygiene, medical use, eye irrigation, EVA operations, and reentry loading as well as 

crew recovery. Water’s launch mass is prohibitive for transfer into space and its limited supply makes recycling 

vital for exploration beyond low-earth orbit. To meet this challenge, in addition to transporting water from 

ground, the ISS utilizes a system that can recycle up to 90% of the fluid captured from hygiene and other 

activities on the ISS from the atmosphere into potable water.

In addition to providing the needed amount of microbiologically safe potable water to each 

crewmember, the system must also ensure that the water is aesthetically acceptable by the crew in 

terms of taste and smell. Special consideration should be taken with treatment chemicals and 

residual biocides. For example, at effective biocidal levels iodine can alter the aesthetics of the 

water as well as cause iodine-related illness. 

NASA-STD-3001 Technical Requirements for WRS

3001 Technical Requirement ECLSS Function

[V2 6026] Potable Water Quality System provides crew with aesthetically acceptable 

potable water that is chemically and 

microbiologically safe for humans.

[V2 6051] Water Contamination Control Prevents potable and hygiene water supply from 

becoming contaminated.

[V2 6109] Water Quantity System provides a minimum, water quantity for 

expected needs of the mission as defined in NASASTD-3001.

[V2 6110] Water Temperature System provides appropriate water temperature as 

defined in NASA-STD-3001.

[V2 6039] Potable Water Dispensing Rate Water is dispensed at a rate compatible with the 

food system.

[V2 6040] Potable Water Dispensing Increments Water is dispensable in specified increments 

compatible with the food system to prevent 

overflow.

Contributors to Water Quality:

• Humidity condensate and urine

• Added biocides

• Microbial and biofilm

• Off-gassing/leaching of materials

• Mission duration

• Trace contaminants

Reference OCHMO-TB-027 

Water for additional 

information.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 12

Calcium deposits affect Urine Processing Assembly (UPA)

The UPA’s distillation assembly helps transform urine from crew members into usable water. 

With its initial use, the distillation assembly struggled with calcium sulfate build-up in the processing unit. 

Due to microgravity induced bony turnover, there is an increase in urinary calcium excretion leading to 

buildup of calcium sulfate in the UPA that interfered with successful hardware functioning. The distillation 

and processing procedure was changed and the water recovery rate was reduced to prevent the 

precipitation causing the buildup, then the pretreat chemicals were changed to allow for a higher water 

recovery rate. The new Brine Processing Assembly (BPA) allowed for the recovery of >90% of water.

Reference OCHMO-TB030 Bone Loss and 

OCHMO-TB-031 Exercise 

Overview for additional 

information.

Urine calcium deposits in 

UPA of ISS

Source: Williamson, Wilson, & Gleich (2022). Status of ISS 

Water Management and Recovery 

Increased Risk of Renal Stones

Calcium in the urine not only caused problems with the UPA equipment, 

but concern was raised regarding the potential for renal stone 

development due to increased urine calcium concentrations. Renal 

stones are associated with debilitating pain, blockage of the ureter, 

kidney infections, and kidney damage. NASA continues to study ways to 

decrease the risk of renal stones. 

Renal Stone Countermeasures

• Increase water intake, as dehydration can increase renal stone risk.

• Pharmaceuticals including potassium citrate, which can decrease 

stone formation, and bisphosphonates to decrease bone breakdown.

• Exercise to decrease bone loss.

• Ultrasounds are being studied to move or breakdown stones if they do 

occur.

[V2 6109] Water Quantity The 

system shall provide a minimum 

water quantity as specified in 

Table 4, Water Quantities and 

Temperatures (NASA-STD-3001 

Volume 2) for the expected needs 

of each mission, which should be 

considered mutually independent.

[V2 7038] Physiological 

Countermeasures The system 

shall provide countermeasures to 

meet crew bone, muscle, 

sensorimotor, thermoregulation, 

and aerobic/cardiovascular 

requirements defined in NASASTD-3001, Volume 1.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

11/14/2023

Rev B 13

ECLSS Fire Detection and Suppression

The Fire Detection and Suppression subsystem provides fire detection sensors for the Station, fire 

extinguishers, portable breathing equipment, and a system of alarms and automatic software actions to alert 

the crew and automatically respond to a fire. Similar systems are required on all crewed vehicles.

Fire Detection and Suppression (FDS) – U.S. Modules

• Each module equipped with detectors and alarms that alert the crew of a potential fire event

• Fire detectors detect smoke through laser-based scatter/obscuration detection

• Fire suppression performed by applying CO2 with a portable fire extinguisher tank – CO2 was elected as the 

primary fire suppression agent on ISS based on its compatibility with the ECLSS design to remove excess CO2

from the atmosphere

• Other types of fire extinguishers include water mist extinguishers and fire cartridges

• Two fire extinguishers located in each module and two Portable Breathing Apparatuses (PBAs) that dispense 

oxygen available in each module to support crew during fire emergencies

• Combustion Product Monitor (CPM) laser absorption spectrometer measures ambient gas phase 

concentrations of CO, HCI, HCN, HF, and CO2.

During and after a fire event, contaminant readings are taken frequently (several per hour). This 

frequent sampling allows the crew and ground to have insight into whether contaminant levels are 

quickly rising and approaching (or at) levels requiring masks to be donned. These measurements are 

necessary to ensure that the crew does not experience acute exposure to contaminants that may pose 

a risk to crew health.

Portable fire extinguishers

NASA-STD-3001 Technical Requirements for 

FDS

3001 Technical 

Requirement ECLSS Function

[V2 6024] 

Combustion 

Monitoring and 

Alerting

System monitors in real-time 

for toxic atmosphere 

components that would 

result from pre-combustion 

and combustion events.

[V2 9059] Fire 

Detecting, 

Warning, and 

Extinguishing.

Vehicles contain a fire 

protection system to detect, 

warn, and extinguish fires 

without creating a 

hazardous environment.

Reference OCHMO-TB-008 Fire Protection

for additional information.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

11/14/2023

Rev B 14

Future Exploration Considerations

Multi-Mission Space Exploration Vehicle (MMSEV)

An ECLSS design for the MMSEV is currently under development. A rudimentary fluid schematic was 

developed during the Constellation Lunar Surface Systems Program for a surface rover’s flight ECLSS. This 

schematic was implemented and improved upon and now encompasses a vehicle that supports micro gravity, 

planetary, and lunar missions. Contingencies considered during these iterative design cycles are feed the leak 

and depress/repress cycle of the cabin atmosphere in case of fire, and a rescue of crew with a 72-hour 

duration to the base/lander.

Current Parts of the MMSEV ECLSS:

• Pressure Control System (PCS) -regulates cabin total pressure and constituent partial pressures

• Air Revitalization System (ARS) – provides cabin air circulation and thermal control. Trace contaminant 

control, CO2 scrubbing, recuperates moisture, and atmospheric monitoring

• Waste Control System (WCS) – collects and stores human metabolic waste and food and packaging waste

• Potable Water System (PWS) – dispenses both hot and cool potable water for drink and meal preparations 

and hygiene

For additional information: Stambaugh et al. (2013). Environmental Controls and Life Support System (ECLSS) 

Design for a Multi-Mission Space Exploration Vehicle (MMSEV). 43rd International Conference on 

Environmental Systems. https://doi.org/10.2514/6.2013-3428

Closed-Loop Life Support

For future long-term missions to the Moon or Mars, lasting months to years, it won’t be practical to bring all 

the required supplies or rely on re-supply. Thus, there is a need to establish a closed loop system that can 

reclaim and recycle water and other wastes. This type of system could recycle feces, urine, and CO2 to provide 

water and food to the crew and greatly reduce the mass needed to pack enough supplies for long-duration 

missions. 

For additional information: Environmental Control and Life-support Subsystem (ECLSS). Chapter 4.4.1.

Bioregenerative Life-support 

Subsystems: For long space missions 

to Mars or beyond, bioregenerative 

life support sub-systems may be 

needed. These systems allow us to 

“close the loop” and recycle all 

human waste into food, water, and 

oxygen.
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Back-Up

11/14/2023

Rev B 15
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

11/14/2023

Rev B 16

Rev A  Rev B

• Updated information to be consistent with NASA-STD-3001 

Volume 1 Rev C and Volume 2 Rev D.

Original  Rev A

• Added information regarding exercise, oxygen intake, and 

carbon dioxide output.

Major Changes Between Revisions
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Information

11/14/2023

Rev B 17

History of ECLSS

Space 

Vehicle ECLSS Parameters Potable Water System Water Cleaning

Mercury

• Pressure suit revitalize atmosphere 

supply, control crew temp/humidity

• Cabin control cabin ventilation, 

temperature, atmospheric pressure

• Pre-filled ground supplied 2.5 

kg water pouch with , water 

transferred from water pouch 

to crew with drink tube, 

delivered on demand by 

squeezing pouch

• Local ground disinfection 

of source water, no 

additional biocide added

Gemini

• Mercury cabin/suit system with 

added:

• Weight and power reducing oxygen 

storage, integrated heat 

exchange/water separator

• Modular construction ECLSS 

components

• First attempt (unsuccessful), 

to use fuel cell-produced 

water,

• Used fill and draw with ground 

supplied water

• Water stored in bladder tanks

• Water gun delivered water to 

crew

• Chlorine supplied prior to 

launch

Apollo

• Mercury Cabin/suit system

• Two separate systems: 

Crew module & Lunar life support

• Service module water and electricity

• Safer 60%/40% oxygen/nitrogen 

cabin gas mixture

• Potable water from fuel cells 

and oxygen supplied from 

service module

• Lunar module used to fill and 

draw as no fuel cells available

• Crew module used 

chlorine with additional 

sodium hypochlorite

• Lunar module used 

Iodine

Skylab

• Two-level Airlock module

• Stored water and oxygen

• Regenerable molecular sieve for C02

and humidity removal

• Mixed oxygen/nitrogen atmosphere

• Ultraviolet fire detectors

• Fill and draw system design.

• System contained equipment 

for storage, microbial control, 

and distribution of water

• Water provided to service the 

life support umbilical's, 

pressure control units, and fire 

hose.

• Multiple water tanks 

throughout vehicle

• Iodine including a water 

purification system to 

sample iodine level in 

tanks

Shuttle

• Pressure control, fire control, air 

revitalization, active and passive 

thermal monitoring 

• Lithium oxide air revitalization

• Thermal freon loop

• Water is supplied via fuel cells 

following passage through a 

hydrogen separator

• Iodine disinfection via 

microbial check value 

(MCV)
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Information

11/14/2023

Rev B 18

Spacesuit - Extravehicular Mobility Unit (EMU) Portable Life Support System (PLSS)

When a crewmember is preforming a spacewalk, the spacesuit is essentially an independent spacecraft 

with its own ECLSS system, called the PLSS. The PLSS provides pressure control, atmosphere 

revitalization, and thermal control in order to maintain a comfortable habitable environment for the 

crewmember. The PLSS maintains a pure O2 atmosphere at approximately 4.2 psi which provides high 

enough ppO2 for respiration while low enough to not cause restrictions on crew motion. 

PLSS Functions:

• Supplies oxygen for breathing and suit ventilation

• Removes CO2 via Lithium Hydroxide (LiOH) or METOX cartridge, contaminants, and humidity from suit 

atmosphere

• Provides thermal control through water coolant loop circulating through Liquid Cooling Ventilation 

Garment (LCVG) into PLSS where heat is rejected via sublimator

• LCVG is worn under the spacesuit to cool the crewmember, with water traveling through tubing to 

help regulate temperature

• Regulates suit pressure

• Monitors astronaut health and critical suit parameters

PLSS Primary Subsystems:

Primary oxygen supply: supplies oxygen for breathing and pressurizes the suit and helmet

Oxygen ventilation: circulates oxygen through the spacesuit pressure garment and purifies recirculating 

oxygen, helps to cool astronaut by evaporating moisture that accumulates on skin

Liquid transport loop: water enters the system and circulates chilled water through network of plastic 

tubing integrated in the LCVG then travels 

through the sublimator where heat is 

removed and cooled water is used to cool 

the fan motor before returning to the 

LCVG.

Feedwater loop: supplies expendable 

water to sublimator for cooling; water 

passed through the sublimator which 

absorbs system heat and discharges hot 

water to the outside

Electrical power subsystem: provides

electrical power to fan and pump motor 

assemblies

Emergency Supplemental Oxygen system 

(SOP): supplies additional 30-90 minutes 

of oxygen if Primary Oxygen System fails
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 4015] Aerobic Capacity The system shall be operable by crewmembers with the aerobic capacity as 

defined in NASA-STD-3001, Volume 1.

[V2 6001] Trend Analysis of Environmental and Suit Data The system shall provide environmental and suit 

monitoring data in formats compatible with performing temporal trend analyses.

[V2 6002] Inert Diluent Gas Cabin atmospheric composition shall contain at least 30% diluent gas 

(assuming balance oxygen).

[V2 6003] O2 Partial Pressure Range for Crew Exposure The system shall maintain inspired oxygen partial 

pressure (PIO2) in accordance with Table 1, Inspired Oxygen Partial Pressure Exposure Ranges.

[V2 6004] Nominal Vehicle/Habitat Carbon Dioxide Levels The system shall limit the average one-hour 

CO2 partial pressure (PICO2) in the habitable volume to no more than 3 mmHg.

[V2 6006] Total Pressure Tolerance Range for Indefinite Crew Exposure The system shall maintain the 

pressure to which the crew is exposed to between 34.5 kPa < pressure ≤ 103 kPa (5 psia < pressure ≤ 15.0 

psia) for indefinite human exposure without measurable impairments to health or performance. 

[V2 6007] Rate of Pressure Change For pressure changes >1.0 psi, the rate of change of total internal 

vehicle pressure shall not exceed 13.5 psi/min.

[V2 6150] Barotrauma Prevention During a commanded pressure change, the system shall pause within 1 

psi of the pause command being issued by the unsuited or suited crewmember, with ability to increase or 

decrease pressure as needed after the pause.

[V2 6008] Decompression Sickness (DCS) Risk Identification Each program shall define mission-unique DCS 

mitigation strategies to achieve the level of acceptable risk of DCS as defined below within 95% statistical 

confidence: a. DCS ≤ 15% (includes Type I or isolated cutis marmorata). b. Grade IV venous gas emboli (VGE) 

≤ 20%. c. Prevent Type II DCS.

[V2 6009] Decompression Sickness Treatment Capability The system shall provide DCS treatment 

capability.

[V2 6011] Post Landing Relative Humidity (RH) For nominal post landing operations, the system shall limit 

RH to the levels in Table 6.2-2—Average Relative Humidity Exposure Limits for Post Landing Operations.

[V2 6012] Crew Health Environmental Limits The system shall maintain levels of cabin humidity and 

temperature within the boundaries of the Operating Limits as shown in Figure 6.2-2—Crew Health 

Environmental Limits, to protect for crew health during pressurized operations when crew occupies the 

cabin, excluding suited operations, ascent, entry, landing, and post landing.

[V2 6013] Crew Performance Environmental Zone The system shall be capable of reaching atmospheric 

humidity and temperatures of nominally occupied habitable volumes within the zone provided in Figure 

6.2-3—Crew Performance Environmental Zone, during all nominal operations, excluding suited operations, 

ascent, entry, landing, and post landing.

[V2 6151] Temperature Selectability The system shall provide selectable set points for internal atmosphere 

temperature in step sizes no greater than 0.5°C increments with a setpoint error of +/- 1.5°C in the 

habitable volume. 

[V2 6152] Temperature Adjustability The system shall be capable of adjusting temperature in the habitable 

volume by at least 1°C/hr.

Referenced Technical Requirements

11/14/2023

Rev B 19

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6014] Crewmember Heat Storage The system shall prevent the energy stored by each crewmember 

from exceeding the cognitive deficit onset (CDO) limits defined by the range 4.7 kJ/kg (2.0 Btu/lb) > ΔQ 

stored > -4.1 kJ/kg (-1.8 Btu/lb) during pre-launch operations, ascent, entry, descent, landing, postlanding,

contingency, and suited operations longer than 12 hours, where ΔQ stored is calculated using a validated 

and NASA approved thermoregulatory model, such as 41-Node Man (JSC-33124, 41-Node Transient 

Metabolic Man Computer Program Documentation – A thermal regulatory model of the human body with 

environmental suit applications) or the Wissler model.

[V2 7041] Environmental Control During Exercise The system environmental control shall accommodate 

the increased O2 consumption and additional output of heat, CO2, perspiration droplets, odor, and 

particulates generated by the crew in an exercise area.

[V2 6017] Atmospheric Control The system shall allow for local and remote control of atmospheric 

pressure, humidity, temperature, ventilation, and ppO2.

[V2 6020] Atmospheric Data Recording For each isolatable, habitable compartment, the system shall 

automatically record pressure, humidity, temperature, ppO2, and ppCO2 data continuously.

[V2 6021] Atmospheric Data Displaying The system shall display real-time values for pressure, humidity, 

temperature, ppO2, and ppCO2 data to the crew locally and remotely.

[V2 6022] Atmospheric Monitoring and Alerting Parameters The system shall alert the crew locally and 

remotely when atmospheric parameters, including atmospheric pressure, humidity, temperature, ppO2, 

and ppCO2 are outside safe limits.

[V2 6023] Trace Constituent Monitoring and Alerting The system shall monitor trace volatile organic 

compounds (VOCs) in the cabin atmosphere and alert the crew locally and remotely when they are 

approaching defined limits.

[V2 6024] Combustion Monitoring and Alerting The system shall monitor in real-time the toxic 

atmospheric components listed in Table 6.2-3—Recommended Combustion Product (CP) Monitoring 

Ranges, that would result from pre-combustion and combustion events in the ranges and with the 

accuracy and resolution specified in the table and alert the crew locally and remotely in sufficient time for 

them to take appropriate action.

[V2 6025] Contamination Monitoring and Alerting The system shall monitor and display atmospheric 

compound levels that result from contamination events, e.g., toxic release, systems leaks, or externally 

originated, before, during, and after an event and alert the crew locally and remotely in sufficient time for 

them to take appropriate action.

[V2 6153] Celestial Dust Monitoring and Alerting The vehicle shall monitor celestial dust and alert the 

crew locally and remotely when they are approaching defined limits. 

[V2 6107] Nominal Vehicle/Habitat Atmospheric Ventilation The system shall maintain a ventilation rate 

within the internal atmosphere that is sufficient to provide circulation that prevents CO2 and thermal 

pockets from forming, except during suited operations, toxic cabin events, or when the crew is not 

inhabiting the vehicle.

[V2 6108] Off-Nominal Vehicle/Habitat Atmospheric Ventilation The system shall control for ppO2, 

ppCO2, and relative humidity during off-nominal operations, such as temporary maintenance activities in 

areas not in the normal habitable volume.

Referenced Technical Requirements

11/14/2023

Rev B 20

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6050] Atmosphere Contamination Limit The system shall limit gaseous pollutant accumulation in the 

habitable atmosphere below individual chemical concentration limits specified in JSC-20584, Spacecraft 

Maximum Allowable Concentrations for Airborne Contaminants (SMACs).

[V2 6052] Particulate Matter The system shall limit the habitable atmosphere particulate matter 

concentration for total dust to <3 mg/m3 with a crew generation rate of 1.33 mg/person-minute, and the 

respirable fraction of the total dust <2.5 μm (micrometer) in aerodynamic diameter to <1 mg/m3 with a 

crew generation rate of 0.006 mg/person-minute.

[V2 6053] Lunar Dust Contamination The system shall limit the levels of lunar dust particles less than 10 

μm in size in the habitable atmosphere below a time-weighted average of 0.3 mg/m3 during intermittent 

daily exposure periods that may persist up to 6 months in duration.

[V2 6059] Microbial Air Contamination The system shall provide air in the habitable atmosphere that is 

microbiologically safe for human health and performance.

[V2 6026] Potable Water Quality At the point of crew consumption or contact, the system shall provide 

aesthetically acceptable potable water that is chemically and microbiologically safe for human use, 

including drinking, food rehydration, personal hygiene, and medical needs.

[V2 6051] Water Contamination Control The system shall prevent potable and hygiene water supply 

contamination from microbial, atmospheric (including dust), chemical, and non-potable water sources to 

ensure that potable and hygiene water are provided.

[V2 6046] Water Quality Monitoring The system shall provide the capability to monitor water quality and 

notify the crew locally and remotely when parameters are approaching defined limits. 

[V2 6109] Water Quantity The system shall provide a minimum water quantity as specified in Table 6.3-

1—Water Quantities and Temperatures, for the expected needs of each mission, which should be 

considered mutually independent.

[V2 6110] Water Temperature The system shall provide the appropriate water temperature as specified in 

Table 6.3-1—Water Quantities and Temperatures, for the expected needs of each mission and task.

[V2 6039] Potable Water Dispensing Rate Water shall be dispensed at a rate that is compatible with the 

food system.

[V2 6040] Potable Water Dispensing Increments To prevent overflow, water shall be dispensable in 

specified increments that are compatible with the food preparation instructions and time demands of the 

allotted meal schedule.

[V2 6047] Toxic Hazard Level Three The system shall use only chemicals that are Toxic Hazard Level Three 

or below, as defined in JSC-26895, Guidelines for Assessing the Toxic Hazard of Spacecraft Chemicals and 

Test Materials, in the habitable volume of the spacecraft.

[V2 6048] Toxic Hazard Level Four The system shall prevent Toxic Hazard Level Four chemicals, as defined 

in JSC-26895, from entering the habitable volume of the spacecraft.

[V2 6049] Chemical Decomposition The system shall use only chemicals that, if released into the 

habitable volume, do not decompose into hazardous compounds that would threaten health during any 

phase of operations.

Referenced Technical Requirements

11/14/2023

Rev B 21

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6060] Biological Payloads Biological payloads, as well as the associated operational procedures and 

supporting personal protective equipment, shall meet the criteria defined by the JSC Biosafety Review 

Board guidelines contained in JPR-1800.5, Biosafety Review Board Operations and Requirements.

[V2 6061] Environment Cross-Contamination The system shall provide controls to prevent or otherwise 

minimize (as appropriate) biological cross-contamination between crew, payloads and vehicles to 

acceptable levels in accordance with the biosafety levels (BSL) defined in JPR-1800.5, as well between 

crew, payloads, vehicles and extraterrestrial planetary environments with the extent of application specific 

to individual planetary bodies and special locations thereon.

[V2 6063] Contamination Cleanup The system shall provide a means to remove or isolate released 

chemical and biological contaminants and to return the environment to a safe condition.

[V2 7020] Body Waste Management Capability The system shall provide the capability for collection, 

containment, and disposal of body waste for both males and females.

[V2 7025] Body Waste Containment The system shall prevent the release of body waste from the waste 

management system.

[V2 7110] Food and Impacts to Environmental Systems Food items and packaging shall be evaluated for 

impacts on vehicle systems.

[V2 7115] Medical Treatment, Personal Supplies, and Impacts to Environmental Systems Medical 

treatment, including pharmaceuticals, non-pharmaceutical crew care items, and related supplies, shall be 

evaluated for impacts on vehicle systems.

[V2 9059] Fire Detecting, Warning, and Extinguishing The vehicle shall have a fire protection system 

composed of detecting, warning, and extinguishing devices that do not create a hazardous environment to 

all spacecraft volumes during all mission phases.

Referenced Technical Requirements

11/14/2023

Rev B 22

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-002

Environmental Control & Life Support System 

(ECLSS): Human-Centered Approach

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference List

1. Active Thermal Control System Overview. Boeing IDS Business Support, Communications, and Community 

Affairs. https://www.nasa.gov/pdf/473486main_iss_atcs_overview.pdf

2. Smith, F., Perry, J., Murdoch, K., and Goldblatt, L. (2004). Sabatier Carbon Dioxide Reduction Assembly Development 

for Closed Loop Water Recovery. NASA JSC-CN-8299.

3. The International Space Station Operating and Outpost in the New Frontier. Robert Dempsey, Executive Editor. 

https://www.nasa.gov/sites/default/files/atoms/files/iss-operating_an_outpost-tagged.pdf

4. Orion ECLSS Lecture. Internal NASA Document.

5. NASA Engineering and Safety Center ECLSS Lecture. Internal NASA Document.

6. Peterson, Laurie J., and Michael R. Callahan. Overview of Potable Water Systems on Spacecraft Vehicles and 

Applications for the Crew Exploration Vehicle (CEV). SAE Transactions, vol. 116, 2007, pp. 492–503. JSTOR.

7. Stambaugh et al. (2013). Environmental Controls and Life Support System (ECLSS) Design for a Multi-Mission Space 

Exploration Vehicle (MMSEV). 43rd International Conference on Environmental Systems. 

https://doi.org/10.2514/6.2013-3428

8. Environmental Control and Life-support Subsystem (ECLSS). Chapter 4.4.1.

9. Lindeboom, R.E.F., Paepe, J.D., Vanoppen, M., Alonso-Farinas, B., Coessens, W., Alloul, A., et al. (2020). A five-stage 

treatment train for water recovery from urine and shower water for long-term human Space missions. Desalination, 

495, 114634.

10. Water Recovery System, International Space Station. Retrieved from: https://www.watertechnology.net/projects/iss_water_recovery

11. Tobias, B., Garr, J.D., and Erne, M. (2011). International Space Station Water Balance Operations. JSC-CN-23995.

12. Keeping Cool in Space: Suit Design. Retrieved from: https://www.youtube.com/watch?v=AwUvh9sluOA

13. Portable Life Support System. Retrieved from: 

https://www.hq.nasa.gov/alsj/LM15_Portable_Life_Support_System_ppP1-5.pdf

14. Primary life support system. Retrieved from: https://en.wikipedia.org/wiki/Primary_life_support_system

15. Environment Control and Life Support System (ECLSS). International Space Station. ESA-HSO-COU-030. Retried from: 

http://wsn.spaceflight.esa.int/docs/Factsheets/30%20ECLSS%20LR.pdf

16. Collins, M.A. (2001). Fire Protection in Manned Missions: Current and Planned. Halon Options Technical Working 

Conference, 24-26. Retrieved from: https://www.nist.gov/system/files/documents/el/fire_research/R0200469.pdf

17. Life support system. (2018). New World Encyclopedia. Retrieved from: 

https://www.newworldencyclopedia.org/entry/Life_support_system

18. Ewert, M.K., and Stromgren, C. (2019). Astronaut Mass Balance for Long Duration Missions. 49th International 

Conference on Environmental Systems. ICES-2019-126. Retrieved from: https://ttuir.tdl.org/bitstream/handle/2346/84881/ICES-2019-126.pdf?sequence=1

19. Georgescu, M.R., Meslem, A., Nastase, I., and Bode, F. (2021). Personalized ventilation solutions for reducing CO2 

levels in the crew quarters of the International Space Station. Building and Environment, 204: 108150

21. Risk of Hypobaric Hypoxia from the Exploration Atmosphere. Norcross, J et al. Human Research Program Nov 13,2015. 

NASA JSC Houston TX. 

22. Smith, S.M., McCoy, T., Gazda, D., Morgan, J.L.L., Heer, M., and Zwart, S.R. (2012). Space Flight Calcium: Implications 

for Astronaut Health, Spacecraft Operations, and Earth. Nutrients, 4(12): 2047-2068. 

23. Muirhead, D., Carter, L., and Williamson, J. (2018). Preventing Precipitation in the ISS Urine Processor. 48th 

International Conference on Environmental Systems. ICES-2018-87. Retrieved from: https://ttuir.tdl.org/bitstream/handle/2346/74086/ICES_2018_87.pdf?sequence=1&isAllowed=y

24. Steller, J.G., Blue, R., Zahner, C., Frisch, E.H., Bayuse, T., Aunon-Chancellor, S., and Jennings, R.T. (2021). Menstrual 

management considerations in the space environment. REACH – Reviews in Human Space Exploration, 23-24.

25. Williamson,J.,Wilson,J,.Gleich,A,.(2022). Status of ISS Water Management and Recovery 51st Ingternational Conference 

on Environmental Systems 10-1 July 2022 St. Paul,MN.

11/14/2023

Rev B 23