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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Impedances of Li/SO2 cells retrieved from the Long Duration Exposure Facility (LDEF satellite) and comparison with cells stored terrestrially

Impedances were measured on several Li/SO2 cells retrieved from the Long Duration Exposure Facility (LDEF) satellite. These cells were used to power instruments and recorders and had all been partially or fully discharged. Impedances were also measured on several cells that were stored in cold storage since manufacture. Unfortunately, none of the cells stored terrestrially had undergone any discharge, whereas all of the cells on the satellite were at least partially discharged early in the mission and then remained on orbit for about 5 years further. It has been observed by others that storage of an Li/SO2 cell after partial discharge, increases the resistance and thickness of the passive film on the Li electrode, as indicated by an increase in the time for recovery of voltage when a load is applied (voltage lag), or in some cases by an inability of a cell to sustain a normal current after such storage. Since the cells stored terrestrially were not discharged in the same manner as the LDEF cells, a direct comparison cannot be made. Thus, the effects of the space environment cannot be separated from the effects of storage after partial discharge. It is believed that the increases in impedance in the LDEF cells are largely due to the storage upon partial discharge rather than the effects of the space environment.

Reid, Margaret A.↗
NASA NTRS2010

Development of an Integrated Countermeasure Device for Long Duration Space Flight and Exploration Missions

Musculoskeletal, cardiovascular, and sensorimotor deconditioning have been observed consistently in astronauts and cosmonauts following long-duration spaceflight. Studies in bed rest, a spaceflight analog, have shown that high intensity resistive or aerobic exercise attenuates or prevents musculoskeletal and cardiovascular deconditioning, respectively, but complete protection has not been achieved during spaceflight. Exercise countermeasure hardware used during earlier International Space Station (ISS) missions included a cycle ergometer, a treadmill, and the interim resistive exercise device (iRED). Effectiveness of the countermeasures may have been diminished by limited loading characteristics of the iRED as well as speed restrictions and subject harness discomfort during treadmill exercise. The Advanced Resistive Exercise Device (ARED) and the second generation treadmill were designed to address many of the limitations of their predecessors, and anecdotal reports from ISS crews suggest that their conditioning is better preserved since the new hardware was delivered in 2009. However, several countermeasure devices to protect different physiologic systems will not be practical during exploration missions when the available volume and mass will be severely restricted. The combined countermeasure device (CCD) integrates a suite of hardware into one device intended to prevent spaceflight-induced musculoskeletal, cardiovascular, and sensorimotor deconditioning. The CCD includes pneumatic loading devices with attached cables for resistive exercise, a cycle for aerobic exercise, and a 6 degree of freedom motion platform for balance training. In a proof of concept test, ambulatory untrained subjects increased muscle strength (58%) as well as aerobic capacity (26%) after 12-weeks of exercise training with the CCD (without balance training), improvements comparable to those observed with traditional exercise training. These preliminary results suggest that this CCD can concurrently improve musculoskeletal and cardiovascular conditioning in ambulatory subjects, but further work is required to validate its use as countermeasure to spaceflight-induced deconditioning.

Lee, S. M. C.↗
NASA NTRS2015

A Biologically-Based Alternative Water Processor for Long Duration Space Missions

A wastewater recovery system has been developed that combines novel biological and physicochemical components for recycling wastewater on long duration space missions. Functionally, this Alternative Water Processor (AWP) would replace the Urine Processing Assembly on the International Space Station and reduce or eliminate the need for the multifiltration beds of the Water Processing Assembly (WPA). At its center are two unique game changing technologies: 1) a biological water processor (BWP) to mineralize organic forms of carbon and nitrogen and 2) an advanced membrane processor (Forward Osmosis Secondary Treatment) for removal of solids and inorganic ions. The AWP is designed for recycling larger quantities of wastewater from multiple sources expected during future exploration missions, including urine, hygiene (hand wash, shower, oral and shave) and laundry. The BWP utilizes a single-stage membrane-aerated biological reactor for simultaneous nitrification and denitrification. The Forward Osmosis Secondary Treatment (FOST) system uses a combination of forward osmosis (FO) and reverse osmosis (RO), is resistant to biofouling and can easily tolerate wastewaters high in non-volatile organics and solids associated with shower and/or hand washing. The BWP was operated continuously for over 300 days. After startup, the mature biological system averaged 85% organic carbon removal and 44% nitrogen removal, close to maximum based on available carbon. The FOST has averaged 93% water recovery, with a maximum of 98%. If the wastewater is slighty acidified, ammonia rejection is optimal. This paper will provide a description of the technology and summarize results from ground-based testing using real wastewater.

Barta, Daniel J.↗
NASA NTRS2017

Characterization of the NEXT Hollow Cathode Inserts After Long-Duration Testing

Hollow dispenser cathode inserts are a critical element of electric propulsion systems, and should therefore be well understood during long term operation to ensure reliable system performance. This work destructively investigated cathode inserts from the NEXT long-duration test which demonstrated 51,184 hours of high-voltage operation, 918 kg of propellant throughput, and 35.5 MN-s of total impulse. The characterization methods used include scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction. Microscopy analysis has been performed on fractured surfaces, emission surfaces, and metallographically polished cross-sections of post-test inserts and unused inserts. Impregnate distribution, etch region thickness, impregnate chemical content, emission surface topography, and emission surface phase identification are the primary factors investigated.

life (durability)↗
NASA NTRS2017

Characterization of the NEXT Hollow Cathode Inserts After Long-Duration Testing

Hollow dispenser cathode inserts are a critical element of electric propulsion systems, and should therefore be well understood during long term operation to ensure reliable system performance. This work destructively investigated cathode inserts from the NEXT long-duration test which demonstrated 51,184 hours of high-voltage operation, 918 kg of propellant throughput, and 35.5 MN-s of total impulse. The characterization methods used include scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction. Microscopy analysis has been performed on fractured surfaces, emission surfaces, and metallographically polished cross-sections of post-test inserts and unused inserts. Impregnate distribution, etch region thickness, impregnate chemical content, emission surface topography, and emission surface phase identification are the primary factors investigated.

Mackey, Jonathan A.↗
NASA NTRSDate not supplied

Behavioral Health Factors in Long Duration Space Flight: Lessons Learned From Apollo And Their Implications For Artemis

Behavioral health will be a critical factor in future Long Duration Spaceflights (LDSF). As humans venture further from Earth, astronauts will face greater isolation and need to be more autonomous than ever before. Astronauts will face a plethora of stressors, both internally and externally, and it will be mission critical to optimize their mind and bodies to endure and overcome these challenges. Personalities, environmental and physical factors will affect each individual and crew in different ways and it will be important to look at these factors independently and as a whole to maximize the chances of a successful mission. By analyzing environments analogous to space and building upon the lessons learned from the Apollo missions and over 50 years of Low Earth Orbit spaceflight, we hypothesize that a general framework can be developed to optimize crew mental wellbeing.

Nicolas Heft↗
NASA NTRS1987

The cause of high-intensity long-duration continuous AE activity (HILDCAAS) - Interplanetary Alfven wave trains

It is shown that high intensity (AE of greater than 1,000 nT), long duration (T of greater than 2d) continuous auroral activity events are caused by outward (from the sun) propagating interplanetary Alfven wave trains. The Alfven waves are often (but not always) detected several days after major interplanetary events, such as shocks and solar wind density enhancements. Presumably, magnetic reconnection between the southward components of the Alfven wave magnetic fields and magnetospheric fields is the mechanism for transfer of solar wind energy to the magnetosphere.

Tsurutani, Bruce T.↗
NASA NTRS1989

High-resolution X-ray spectra of solar flares. IX - Mass upflow in the long-duration flare of 1979 June 5

Blueshifted X-ray spectral line components in Fe and Ca spectra of a large long-duration flare observed on June 5, 1979. It is found that blueshifted emission exists for a time interval of at least 28 minutes indicating upflowing plasma at about 250 km/s. Emission measures for both the blueshifted and stationary plasma are derived and the results are interpreted in terms of chromospheric evaporation. The total amount of hot upflowing plasma during the flare rise time exceeds the amount of stationary plasma contained in the loop close to the time of the peak of the flare. This result contradicts the simplest version of the evaporation model. Evaporation can account for the observations only if some of the upflowing plasma cools on time scales much shorter than the rise time of the event, which was about 40 minutes.

Doschek, G. A.↗
NASA NTRS1989

Artificial gravity for long duration spaceflight

This paper reviews the fundamental physical properties of gravitational and centrifugal forces, describes the physiological changes that result from long-term exposure to the nearly gravity-free environment of space, and explores the nature of these changes. The paper then cites currently employed and advanced techniques that can be used to prevent some of these changes. Following this review, the paper examines the potential use of artificial gravity as the ultimate technique to maintain terrestrial levels of physiological functioning in space, and indicates some of the critical studies that must be conducted and some of the trade-offs that must be made before artificial gravity can intelligently be used for long duration spaceflight.

Cohen, Malcolm M.↗
NASA NTRS1993

Radiation sensitivity of quartz crystal oscillators experiment for the Long Duration Exposure Facility (LDEF), part 2

The stability of high precision quartz crystal oscillators exposed to the radiation environment of NASA's Long Duration Exposure Facility (LDEF) was studied. Comparisons between pre-flight and post-flight frequency drift rates indicate that oscillators made from swept premium Q quartz exhibited a significantly greater post-flight drift rate than before exposure, but that the effect annealed after five months aging at 75 C (the operating temperature). The result that six years worth of radiation damage annealed out in less than six months suggests that if the oscillators had been powered during the LDEF mission, no net change in drift rate beyond their normal baseline value would have occurred.

Ahearn, J. S.↗
NASA NTRS2011

Immune System Dysregulation and Herpesvirus Reactivation Persist During Long-Duration Spaceflight

This poster presentation reviews a study that is designed to address immune system dysregulation and the risk to crewmembers in long duration exploration class missions. This study will address these objectives: (1) Determine the status of adaptive immunity physiological stress, viral immunity, latent herpesvirus reactivation in astronauts during 6 month missions to the International Space Station; (2) determine the clinical risk related to immune dysregulation for exploration class spaceflight; and (3) determine an appropriate monitoring strategy for spaceflight-associated immune dysfunction that could be used for the evaluation of countermeasures. The study anticipates 17 subjects, and for this presentation, (midpoint study data) 10 subjects are reviewed.

Crucian, B. E.↗
NASA NTRS2011

An Integrated Musculoskeletal Countermeasure Battery for Long-Duration Lunar Missions

During extended periods of skeletal unloading, losses in strength and density of the proximal femur will occur. In long-duration spaceflight, resistive exercise is used to replace the normal loads exerted on the spine and hip. At the present time, there is no conclusive evidence that hip bone loss has been prevented in this scenario. Our group has recently developed and clinically evaluated a multifunctional exercise system, the Combined Countermeasure Device (CCD). The CCD comprises a low-footprint Stuart Platform for lower-body resistance exercise and balance training, and a cardiovascular exercise bicycle. A consideration for resistance exercise was targeting of the hip abductor and adductor muscles, which attach directly at the hip and which should subject it to the largest loads. In our training study, we found that CCD exercise increased hip adductor and abductor strength, and modeling results suggest that this exercise exerts forces on the hip of approx. 4-6 body weights at 1g, compared to forces of approx.2.5 body weight y squatting exercise. In our current study, we hypothesize that abductor and adductor exercise will increase the density and strength of the proximal femur.

Lang, T. F.↗
NASA NTRS2012

Antarctic Exploration Parallels for Future Human Planetary Exploration: The Role and Utility of Long Range, Long Duration Traverses

Topics covered include: Antarctic Exploration Parallels for Future Human Planetary Exploration: Science Operations Lessons Learned, Planning, and Equipment Capabilities for Long Range, Long Duration Traverses; Parallels Between Antarctic Travel in 1950 and Planetary Travel in 2050 (to Accompany Notes on "The Norwegian British-Swedish Antarctic Expedition 1949-52"); My IGY in Antarctica; Short Trips and a Traverse; Geologic Traverse Planning for Apollo Missions; Desert Research and Technology Studies (DRATS) Traverse Planning; Science Traverses in the Canadian High Arctic; NOR-USA Scientific Traverse of East Antarctica: Science and Logistics on a Three-Month Expedition Across Antarctica's Farthest Frontier; A Notional Example of Understanding Human Exploration Traverses on the Lunar Surface; and The Princess Elisabeth Station.

Hoffman, Stephen J.↗
NASA NTRS2014

An Alternative Water Processor for Long Duration Space Missions

A new wastewater recovery system has been developed that combines novel biological and physicochemical components for recycling wastewater on long duration human space missions. Functionally, this Alternative Water Processor (AWP) would replace the Urine Processing Assembly on the International Space Station and reduce or eliminate the need for the multi-filtration beds of the Water Processing Assembly (WPA). At its center are two unique game changing technologies: 1) a biological water processor (BWP) to mineralize organic forms of carbon and nitrogen and 2) an advanced membrane processor (Forward Osmosis Secondary Treatment) for removal of solids and inorganic ions. The AWP is designed for recycling larger quantities of wastewater from multiple sources expected during future exploration missions, including urine, hygiene (hand wash, shower, oral and shave) and laundry. The BWP utilizes a single-stage membrane-aerated biological reactor for simultaneous nitrification and denitrification. The Forward Osmosis Secondary Treatment (FOST) system uses a combination of forward osmosis (FO) and reverse osmosis (RO), is resistant to biofouling and can easily tolerate wastewaters high in non-volatile organics and solids associated with shower and/or hand washing. The BWP has been operated continuously for over 300 days. After startup, the mature biological system averaged 85% organic carbon removal and 44% nitrogen removal, close to stoichiometric maximum based on available carbon. To date, the FOST has averaged 93% water recovery, with a maximum of 98%. If the wastewater is slighty acidified, ammonia rejection is optimal. This paper will provide a description of the technology and summarize results from ground-based testing using real wastewater

Barta, Daniel J.↗
NASA NTRS2014

End-of-test Performance and Wear Characterization of NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test

This presentation describes results from the end-of-test performance characterization of NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test (LDT). Sub-component performance as well as overall thruster performance is presented and compared to results over the course of the test. Overall wear of critical thruster components is also described, and an update on the first failure mode of the thruster is provided.

Wear Tests↗
NASA NTRS2017

Long Duration Head Down Tilt Bed Rest and Spaceflight Effects on Neurocognitive Performance: Extent, Longevity and Neural Bases

We have recently completed a long duration head down tilt bed rest (HDBR) study in which we performed structural and functional magnetic resonance brain imaging to identify the relationships between changes in neurocognitive function and neural structural alterations in a spaceflight analog environment. We are also collecting the same measures in crewmembers prior to and following a six month International Space Station mission. We will present data demonstrating that bed rest resulted in functional mobility and balance deterioration with recovery post-HDBR. We observed numerous changes in brain structure, function, and connectivity relative to a control group which were associated with pre to post bed rest changes in sensorimotor function. For example, gray matter volume (GMv) increased in posterior parietal areas and decreased in frontal regions. GMv increases largely overlapped with fluid decreases and vice versa. Larger increases in precentral gyrus (M1)/ postcentral gyrus (S1+2) GMv and fluid decreases were associated with smaller balance decrements. Vestibular activation in the bilateral insular cortex increased with bed rest and subsequently recovered. Larger increases in vestibular activation in multiple brain regions were associated with greater decrements in balance and mobility. We found connectivity increases between left M1 with right S1+2 and the superior parietal lobule, and right vestibular cortex with the cerebellum. Decreases were observed between right Lobule VIII with right S1+2 and the supramarginal gyrus, right posterior parietal cortex (PPC) with occipital regions, and the right superior posterior fissure with right Crus I and II. Connectivity strength between left M1 and right S1+2/superior parietal lobule increased the most in individuals that exhibited the least balance impairments. In sum, we observed HDBR-related changes in measures of brain structure, function, and network connectivity, which correlated with indices of sensorimotor function. Recovery was observed post HDBR but remained incomplete at 12 days post-HDBR. Preliminary findings from our parallel ongoing flight study will be compared and contrasted with bed rest results during this presentation.

Seidler, R. D.↗