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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

An electrochemical study of Ni/2+/, Co/2+/, and Zn/2+/ ions in melts of composition CaMgSi2O6

Results are reported for a study of the behavior of Ni(2+), Co(2+), and Zn(2+) in molten diopside, determined by cyclic voltametry, as a first step in adapting electrochemical methods for use in experimental geochemistry. The techniques used are described, the theory is briefly discussed, and it is demonstrated that Ni(2+), Co(2+), and Zn(2+) can be reduced, then reoxidized in an uncomplicated case of reversible charge transfer at the Pt electrode. This implies that the neutral metal atoms remain undissolved in the melt. The kinetics of the reduction process, the effects of concentration, the standard reduction potentials, and the diffusion coefficients are discussed in detail. The observations are consistent with the mechanism of Ni(2+) diffusion by transport from site to site. As the proportion of SiO2 in the melt increases, a higher activation energy is required for Ni(2+) to move, and the rate of diffusion is lowered.

Semkow, K. W.↗
NASA NTRSDate not supplied

Mitigating Microbial Contamination Risks in CO 2 Removal Systems for Long-Duration Space Missions

Crewed missions to Mars and beyond pose new challenges for the crew and the technological solutions they depend upon. Crucial considerations in designing the next generation of Environmental Control and Life Support Systems (ECLSS) include enhanced reliability and autonomy, given the challenges of resupply and resource recovery in remote missions. One significant challenge faced in various sectors of the International Space Station and ECLSS is the phenomena of microbial growth, particularly biofilm formation. As such, microbial growth is a critical consideration in the design phase of new ECLSS systems. Two novel CO2 removal systems—Liquid-Amines CO2 Removal (LACR) and Cold-Surface CO2 Deposition (CDep)—are currently under development at the NASA Ames Research Center to meet the needs of extended space travel. In this presentation, the authors aim to make a risk assessment of microbial growth in LACR and CDep through: 1) a comprehensive literature review to identify LACR and CDep components most vulnerable to microbial contamination and 2) wet lab testing commencing with a subscale test of the most susceptible component of CDep. The literature review revealed that the hollow-fiber Liqui-Cel membrane employed in CDep exhibits the highest susceptibility to microbial growth. Our wet lab tests corroborated these findings, as airborne microbes introduced into the membrane led to considerable biomass accumulation. These results indicate a significant risk of microbial invasion into the membranes. To prevent microbial growth in CDep or other CO2 removal systems, proper ECLSS arrangement is essential—a CO2 removal system should remain behind the charcoal-HEPA filters, condensing heat exchanger, and Trace Contaminant Control System. In summary, anticipating potential microbial interactions within ECLSS for remote crewed missions is vital to mission success. It should, therefore, be included as one of the many factors when designing future ECLSS systems to perform reliably and consistently to support astronaut life.

A. Nicolas Whitlock↗
NASA NTRSDate not supplied

Real-time Contaminant Evolution from a CO 2 Scrubber

Spaceflight requires recycling and revitalization of cabin air within the spacecraft during missions. Marshall Space Flight Center’s (MSFC) Environmental Control and Life Support Systems Engineering Development Branch (ES-62), develops and tests novel regenerative life support systems, supports the International Space Station (ISS) operations, and plans life support for future missions, such as Gateway and Mars transit.

Jennifer G Williams↗
NASA NTRS2024

Decreased Northern Hemisphere Precipitation from Consecutive CO 2 Doublings Is Associated with Significant AMOC Weakening

Previous studies found many climate properties such as northern hemisphere (NH) surface temperature and precipitation respond non-monotonically when CO2 is increased from 1× to 8×CO2 relative to pre-industrial levels. Here, we explore the robustness of the non-monotonicity in the NH precipitation response in 11 coupled climate models. Eight models show a decrease in NH precipitation under repeated CO2 doubling, indicating that the non-monotonic response is a common but not universal result. Although common, the critical CO2 level where the NH precipitation decrease first occurs differs widely across models, ranging from 2×CO2 to 8×CO2. These models also show a prominent weakening in the Atlantic meridional overturning circulation (AMOC) at the same critical CO2 level, with the AMOC weakening leading the precipitation decrease. The sensitivities of NH precipitation and the AMOC to CO2 doublings are positively correlated, especially when the AMOC weakens beyond 10 Sv. This suggests that the differences in models' AMOC response can explain their contrasting NH precipitation responses, where models with a large AMOC weakening have decreased NH precipitation. Regionally, this decrease in NH precipitation is the most prominent over the North Atlantic, Europe and the tropical Pacific. Our results suggest that special care must be taken with the use of pattern scaling to inform regional climate decision-making.

Atlantic meridional overturning circulation↗