A logical model representing Environmental Control and Life Support Systems (ECLSS) parameters monitored in spacecraft habitat modules.

Measurement of atmospheric gas composition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Oxygen concentration in cabin air, typically around 21%. Crucial for breathing; must stay in safe range to avoid hypoxia or fire risk.

Target is approximately 21%. Alert if below 19.5% (hypoxia risk) or above 23% (fire hazard).

Carbon dioxide concentration in cabin air, measured in parts per million (ppm).

Kept low (thousands of ppm) to prevent crew headaches, dizziness. Alerts if above allowable limit (NASA 3 mmHg ≈ 4000 ppm 1-hr).

Nitrogen concentration in cabin air, typically around 78%.

Primary buffer gas to maintain pressure. Changes may indicate pressure adjustments.

Methane concentration in cabin air, measured in parts per million (ppm).

Typically near 0. Monitored as part of atmospheric quality and as a flammability indicator.

Hydrogen concentration in cabin air, measured in parts per million (ppm).

Should be approximately 0; any reading flags a leak or issue as hydrogen is flammable.

Water vapor partial pressure in cabin air, indicating absolute humidity.

Managed to prevent condensation; relates to approximately 40-60% relative humidity comfort range.

Cabin pressure, temperature and humidity parameters

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Total cabin atmospheric pressure, nominally around 101 kPa.

Vital for habitability; deviations can cause decompression risks.

Cabin air temperature, kept in 18-27°C safe range.

Optimal temperature around 22°C for crew health and comfort.

Relative humidity in cabin air, as a percentage.

Controlled between 30-60% for comfort with limits at 25-75%. Prevents dry air or condensation issues.

Dew point temperature of cabin air in degrees Celsius.

Useful for monitoring moisture load and condensation risk. Derived from humidity and temperature.

Trace contaminants and VOCs in cabin air

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Carbon monoxide concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic gas from fire or malfunctions; triggers immediate alarm if detected.

Ammonia concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic/irritant gas that indicates coolant leaks or contamination.

Formaldehyde concentration in cabin air, measured in parts per million (ppm).

Target approximately 0; common off-gassed irritant. Tracked to ensure long-term exposure stays below SMAC limits.

Measurements of other volatile organic compounds in cabin air.

Used for specific volatile toxins (e.g., benzene, freon) to ensure air remains non-toxic.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Type of volatile organic compound

Concentration in parts per million

Status of air filtration and trace contaminant control systems

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Operational status of the Trace Contaminant Control System.

Values may include: 'nominal', 'standby', 'off', 'fault'

Trace contaminant filter utilization percentage.

High values warn of reduced ability to clean air (filter saturation).

Condition of the cabin air filter.

Values may include: 'nominal', 'partial_clog', 'clogged'. Ensures ventilation efficacy; a clogged filter can lead to poor air quality.

Particulate and microbial measurements

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Airborne particulate concentration, mass of dust/aerosol per volume.

Typically low in a clean cabin; rises if dust or smoke appears.

Number of particles per cubic centimeter above a certain size.

Complements mass concentration as another measure of air cleanliness.

Concentration of microbial colony-forming units in cabin air.

Indicates biological cleanliness of air. May be measured periodically rather than continuously.

Microbial load on surfaces from swab sampling.

High values could contribute to air contamination or crew infection risk.

Radiation measurements and shielding status

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Current ionizing radiation dose rate in the cabin.

Reflects cosmic ray/solar radiation environment; used to assess immediate radiation risk.

Cumulative radiation dose received during the mission.

Tracks long-term exposure against established limits.

Indicates if radiation has crossed thresholds requiring crew action.

Values may include: 'nominal', 'elevated', 'storm'.

Current shielding configuration of the habitat.

Indicates if extra precautions are in effect due to radiation, such as 'standard', 'storm_shelter'.

Percentage of radiation being attenuated by the spacecraft structure.

Optional metric that indicates how much radiation is being blocked.

The date and time when the environmental measurements were recorded.

Reference to the specific module or compartment where these measurements were taken.

Important for spacecraft with multiple habitable volumes that may have different environmental parameters.

Reference to the spacecraft or habitat module where these measurements were taken.

A logical model representing Environmental Control and Life Support Systems (ECLSS) parameters monitored in spacecraft habitat modules.

Measurement of atmospheric gas composition

Oxygen concentration in cabin air, typically around 21%. Crucial for breathing; must stay in safe range to avoid hypoxia or fire risk.

Target is approximately 21%. Alert if below 19.5% (hypoxia risk) or above 23% (fire hazard).

Carbon dioxide concentration in cabin air, measured in parts per million (ppm).

Kept low (thousands of ppm) to prevent crew headaches, dizziness. Alerts if above allowable limit (NASA 3 mmHg ≈ 4000 ppm 1-hr).

Nitrogen concentration in cabin air, typically around 78%.

Primary buffer gas to maintain pressure. Changes may indicate pressure adjustments.

Methane concentration in cabin air, measured in parts per million (ppm).

Typically near 0. Monitored as part of atmospheric quality and as a flammability indicator.

Hydrogen concentration in cabin air, measured in parts per million (ppm).

Should be approximately 0; any reading flags a leak or issue as hydrogen is flammable.

Water vapor partial pressure in cabin air, indicating absolute humidity.

Managed to prevent condensation; relates to approximately 40-60% relative humidity comfort range.

Cabin pressure, temperature and humidity parameters

Total cabin atmospheric pressure, nominally around 101 kPa.

Vital for habitability; deviations can cause decompression risks.

Cabin air temperature, kept in 18-27°C safe range.

Optimal temperature around 22°C for crew health and comfort.

Relative humidity in cabin air, as a percentage.

Controlled between 30-60% for comfort with limits at 25-75%. Prevents dry air or condensation issues.

Dew point temperature of cabin air in degrees Celsius.

Useful for monitoring moisture load and condensation risk. Derived from humidity and temperature.

Trace contaminants and VOCs in cabin air

Carbon monoxide concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic gas from fire or malfunctions; triggers immediate alarm if detected.

Ammonia concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic/irritant gas that indicates coolant leaks or contamination.

Formaldehyde concentration in cabin air, measured in parts per million (ppm).

Target approximately 0; common off-gassed irritant. Tracked to ensure long-term exposure stays below SMAC limits.

Measurements of other volatile organic compounds in cabin air.

Used for specific volatile toxins (e.g., benzene, freon) to ensure air remains non-toxic.

Type of volatile organic compound

Concentration in parts per million

Status of air filtration and trace contaminant control systems

Operational status of the Trace Contaminant Control System.

Values may include: 'nominal', 'standby', 'off', 'fault'

Trace contaminant filter utilization percentage.

High values warn of reduced ability to clean air (filter saturation).

Condition of the cabin air filter.

Values may include: 'nominal', 'partial_clog', 'clogged'. Ensures ventilation efficacy; a clogged filter can lead to poor air quality.

Particulate and microbial measurements

Airborne particulate concentration, mass of dust/aerosol per volume.

Typically low in a clean cabin; rises if dust or smoke appears.

Number of particles per cubic centimeter above a certain size.

Complements mass concentration as another measure of air cleanliness.

Concentration of microbial colony-forming units in cabin air.

Indicates biological cleanliness of air. May be measured periodically rather than continuously.

Microbial load on surfaces from swab sampling.

High values could contribute to air contamination or crew infection risk.

Radiation measurements and shielding status

Current ionizing radiation dose rate in the cabin.

Reflects cosmic ray/solar radiation environment; used to assess immediate radiation risk.

Cumulative radiation dose received during the mission.

Tracks long-term exposure against established limits.

Indicates if radiation has crossed thresholds requiring crew action.

Values may include: 'nominal', 'elevated', 'storm'.

Current shielding configuration of the habitat.

Indicates if extra precautions are in effect due to radiation, such as 'standard', 'storm_shelter'.

Percentage of radiation being attenuated by the spacecraft structure.

Optional metric that indicates how much radiation is being blocked.

The date and time when the environmental measurements were recorded.

Reference to the specific module or compartment where these measurements were taken.

Important for spacecraft with multiple habitable volumes that may have different environmental parameters.

Reference to the spacecraft or habitat module where these measurements were taken.

A logical model representing Environmental Control and Life Support Systems (ECLSS) parameters monitored in spacecraft habitat modules.

Measurement of atmospheric gas composition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Oxygen concentration in cabin air, typically around 21%. Crucial for breathing; must stay in safe range to avoid hypoxia or fire risk.

Target is approximately 21%. Alert if below 19.5% (hypoxia risk) or above 23% (fire hazard).

Carbon dioxide concentration in cabin air, measured in parts per million (ppm).

Kept low (thousands of ppm) to prevent crew headaches, dizziness. Alerts if above allowable limit (NASA 3 mmHg ≈ 4000 ppm 1-hr).

Nitrogen concentration in cabin air, typically around 78%.

Primary buffer gas to maintain pressure. Changes may indicate pressure adjustments.

Methane concentration in cabin air, measured in parts per million (ppm).

Typically near 0. Monitored as part of atmospheric quality and as a flammability indicator.

Hydrogen concentration in cabin air, measured in parts per million (ppm).

Should be approximately 0; any reading flags a leak or issue as hydrogen is flammable.

Water vapor partial pressure in cabin air, indicating absolute humidity.

Managed to prevent condensation; relates to approximately 40-60% relative humidity comfort range.

Cabin pressure, temperature and humidity parameters

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Total cabin atmospheric pressure, nominally around 101 kPa.

Vital for habitability; deviations can cause decompression risks.

Cabin air temperature, kept in 18-27°C safe range.

Optimal temperature around 22°C for crew health and comfort.

Relative humidity in cabin air, as a percentage.

Controlled between 30-60% for comfort with limits at 25-75%. Prevents dry air or condensation issues.

Dew point temperature of cabin air in degrees Celsius.

Useful for monitoring moisture load and condensation risk. Derived from humidity and temperature.

Trace contaminants and VOCs in cabin air

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Carbon monoxide concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic gas from fire or malfunctions; triggers immediate alarm if detected.

Ammonia concentration in cabin air, measured in parts per million (ppm).

Normally 0. Toxic/irritant gas that indicates coolant leaks or contamination.

Formaldehyde concentration in cabin air, measured in parts per million (ppm).

Target approximately 0; common off-gassed irritant. Tracked to ensure long-term exposure stays below SMAC limits.

Measurements of other volatile organic compounds in cabin air.

Used for specific volatile toxins (e.g., benzene, freon) to ensure air remains non-toxic.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Type of volatile organic compound

Concentration in parts per million

Status of air filtration and trace contaminant control systems

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Operational status of the Trace Contaminant Control System.

Values may include: 'nominal', 'standby', 'off', 'fault'

Trace contaminant filter utilization percentage.

High values warn of reduced ability to clean air (filter saturation).

Condition of the cabin air filter.

Values may include: 'nominal', 'partial_clog', 'clogged'. Ensures ventilation efficacy; a clogged filter can lead to poor air quality.

Particulate and microbial measurements

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Airborne particulate concentration, mass of dust/aerosol per volume.

Typically low in a clean cabin; rises if dust or smoke appears.

Number of particles per cubic centimeter above a certain size.

Complements mass concentration as another measure of air cleanliness.

Concentration of microbial colony-forming units in cabin air.

Indicates biological cleanliness of air. May be measured periodically rather than continuously.

Microbial load on surfaces from swab sampling.

High values could contribute to air contamination or crew infection risk.

Radiation measurements and shielding status

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Current ionizing radiation dose rate in the cabin.

Reflects cosmic ray/solar radiation environment; used to assess immediate radiation risk.

Cumulative radiation dose received during the mission.

Tracks long-term exposure against established limits.

Indicates if radiation has crossed thresholds requiring crew action.

Values may include: 'nominal', 'elevated', 'storm'.

Current shielding configuration of the habitat.

Indicates if extra precautions are in effect due to radiation, such as 'standard', 'storm_shelter'.

Percentage of radiation being attenuated by the spacecraft structure.

Optional metric that indicates how much radiation is being blocked.

The date and time when the environmental measurements were recorded.

Reference to the specific module or compartment where these measurements were taken.

Important for spacecraft with multiple habitable volumes that may have different environmental parameters.

Reference to the spacecraft or habitat module where these measurements were taken.