Strategies to Mitigate Ammonia Release on the International Space Station

Macatangay, Ariel V.; Prokhorov, Kimberlee S.; Sweterlitsch, Jeffrey

doi:10.4271/2007-01-3186

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Any ammonia leak into the crew cabin can be fatal to the crew within 5 min. 2 Both CO 2 and NH 3 can be the sources of similar health and safety concerns in industrial plants and buildings and thus form a subset of gases common in indoor and outdoor air quality monitoring.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The National Institute for Occupational Health and Safety (NIOSH) guideline for NH 3 levels with immediate danger to life and health (IDLH) is 300 ppm. Any ammonia leak into the crew cabin can be fatal to the crew within 5 min . Both CO 2 and NH 3 can be the sources of similar health and safety concerns in industrial plants and buildings and thus form a subset of gases common in indoor and outdoor air quality monitoring.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Carboxylated Single-Walled Carbon Nanotube Sensors with Varying pH for the Detection of Ammonia and Carbon Dioxide Using an Artificial Neural Network

Kim¹,

Norman²,

Jones

et al. 2019

ACS Appl. Nano Mater.

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Single-walled carbon nanotubes (SWCNTs) have long been advocated for the detection of various gases and vapors. Often, strategies to modify the nanotubes have been shown to be successful in eliciting a more sensitive response from the nanotubes when exposed to the target gas relative to the pristine material. Carboxylation of the SWCNTs is one such strategy commonly used in gas sensor construction. Interestingly, addition of acid or base to the carboxylation process can change the pH of the resulting material and yield inks with varying pH values that can be used in a sensor array. Here we show orthogonal responses to NH3 and CO2 from eight such materials with controlled pH values in the range of 1.9–12.1. The results and the approach will be applicable to sensing other acidic and basic gases and also can expand further to other sensor systems to maximize and obtain orthogonal sensor responses. A neural network architecture is used successfully to convert the measured resistance change into analyte concentration.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Carboxylated Single-Walled Carbon Nanotube Sensors with Varying pH for the Detection of Ammonia and Carbon Dioxide Using an Artificial Neural Network

Kim¹,

Norman²,

Jones

et al. 2019

ACS Appl. Nano Mater.

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Impacts of Microbial Growth on the Air Quality of the International Space Station

Macatangay

Bruce

2010

40th International Conference on Environmental Systems

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An understanding of the various sources of non-methane volatile organic compounds (NMVOCs) is one facet to ensuring the habitability of crewed spacecraft. Even though the International Space Station (ISS) atmosphere is relatively well characterized in terms of what is in the atmosphere and approximately how much, linking the majority of these trace contaminants detected to their source is virtually impossible. Albeit a few of can be associated to a single source, the majority of these trace contaminants have their origins from multiple sources. On crewed spacecraft such as ISS, trace contaminants are broadly categorized as either coming from equipment, which includes systems and payloads, or from the metabolic processes of the crew members. Such widely encompassing categories clearly illustrate the difficulty in linking air contaminants to their source(s). It is well known that microbial growth in ISS can flourish if left unchecked. Although processes are in place to limit microbial growth, in reality, microbial growth has pervaded the habitable environment of ISS. This is simply a consequence of having crewed spacecraft, as humans are the largest contributor to the bioload. As with crew members, microbes also have metabolic processes which, in many ways, are comparable to human metabolism. As such, it can be expected that microbial growth can lead to the release of volatile organic compounds into the ISS atmosphere. Given a large enough microbial population, the impact to the air quality of ISS can be potentially large. A survey of the microbiology found in ISS will be presented as well as the possible types of volatile organic compounds that can result from such organisms. This will be correlated to the observations provided by ground-based analysis of ISS atmosphere samples

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Impacts of an Ammonia Leak on the Cabin Atmosphere of the International Space Station

Duchesne

Sweterlitsch

Son

et al. 2012

42nd International Conference on Environmental Systems

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Toxic chemical release into the cabin atmosphere is one of the three major emergency scenarios identified on the International Space Station (ISS). The release of anhydrous ammonia, the coolant used in the U.S. On-orbit Segment (USOS) External Active Thermal Control Subsystem (EATCS), into the ISS cabin atmosphere is one of the most serious toxic chemical release cases identified on board ISS. The USOS Thermal Control System (TCS) includes an Internal Thermal Control Subsystem (ITCS) water loop and an EATCS ammonia loop that transfer heat at the interface heat exchanger (IFHX). Failure modes exist that could cause a breach within the IFHX. This breach would result in high pressure ammonia from the EATCS flowing into the lower pressure ITCS water loop. As the pressure builds in the ITCS loop, it is likely that the gas trap, which has the lowest maximum design pressure within the ITCS, would burst and cause ammonia to enter the ISS atmosphere. It is crucial to first characterize the release of ammonia into the ISS atmosphere in order to develop methods to properly mitigate the environmental risk. This paper will document the methods used to characterize an ammonia leak into the ISS cabin atmosphere. A mathematical model of the leak was first developed in order to define the flow of ammonia into the ISS cabin atmosphere based on a series of IFHX rupture cases. Computational Fluid Dynamics (CFD) methods were then used to model the dispersion of the ammonia throughout the ISS cabin and determine localized effects and ventilation effects on the dispersion of ammonia. Lastly, the capabilities of the current on-orbit systems to remove ammonia were reviewed and scrubbing rates of the ISS systems were defined based on the ammonia release models. With this full characterization of the release of ammonia from the USOS TCS, an appropriate mitigation strategy that includes crew and system emergency response procedures, personal protection equipment use, and atmosphere monitoring and scrubbing hardware can be established.https://ntrs.nasa.gov/search.jsp?R=20110023204 2018-05-12T17:22:45+00:00Z

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Strategies to Mitigate Ammonia Release on the International Space Station

Cited by 3 publications

References 14 publications

Carboxylated Single-Walled Carbon Nanotube Sensors with Varying pH for the Detection of Ammonia and Carbon Dioxide Using an Artificial Neural Network

Carboxylated Single-Walled Carbon Nanotube Sensors with Varying pH for the Detection of Ammonia and Carbon Dioxide Using an Artificial Neural Network

Impacts of Microbial Growth on the Air Quality of the International Space Station

Impacts of an Ammonia Leak on the Cabin Atmosphere of the International Space Station

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