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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Analyzing the Subjectivity of Hole-Type Image Quality Indicators for Radiography

Hole-type penetrameters used as image quality indicators (IQIs) for radiography have an inherent degree of subjectivity to their interpretation. The 1T (one times the thickness of the penetrameter) hole is so small, it can be difficult to distinguish from noise. It is suspected that an operator’s knowledge of the true location of the 1T hole may subconsciously influence a false positive identification of the 1T hole when in fact it cannot be discerned. In the case of computed radiography (CR), the size of the phosphor particles may lead to a noise pattern with features on the scale of the 1T hole. Per NASA-STD-5009, the 1T hole must be detected in order to achieve adequate sensitivity. This is based on the historical understanding that this sensitivity will enable detection of the minimum detectable flaw sizes listed in the standard. It’s important to understand if 1T sensitivity is being achieved, and the associated risk if not. This study sought to determine the true detectability of 1T-sized holes in aluminum and Inconel by creating and inspecting a set of penetrameters with randomly placed holes. Enough holes and vacant zones were created to enable a full probability of detection study with 90% detectability, 95% confidence. Testing is ongoing, but preliminary results have shown poor detectability. The detection rate is slightly better for Inconel than aluminum, slightly better using a micro-focus vs. mini-focus tube, and definitively better for film than CR. One of the key questions of this study is whether historical requirements for film are applicable for CR, and these initial findings suggest they may not be. There is also a requirement in the NASA standard for the minimum contrast-to-noise ratio of the hole. The results have shown that this numerical threshold does not correlate well with visual detection. This raises questions about the true nature of detection, in an age of image processing vs. human judgement. As the results indicate that the detection of 1T holes is unreliable, the next challenge will be determining what sensitivity is really achieved, and what is needed.

Erin Lanigan↗
NASA NTRSDate not supplied

Environmental Control and Life Support (ECLS) System Options for Mars Transit and Mars Surface Missions

The NASA led Artemis campaign will take humanity back to the Moon and serve as an analog for continued deep space exploration to Mars. Artemis utilizes crewed vehicles and habitats on both the Lunar surface and in Lunar orbit. The exploration of the Lunar surface and buildup of a basecamp is meant to be a “Mars forward” approach to testing and refining new technologies and techniques for living and working far outside of Low Earth Orbit (LEO) and preparing for future Mars missions. The Lunar Surface Habitat is planned as a primary element for long duration crew habitation on the Moon and will be the primary testbed for ECLS system hardware in a partial gravity environment. The Mars Transit Habitat will be the crew vehicle for the roundtrip from Earth to Mars and spend a significant amount of time docked to the Gateway outfitting and testing its systems prior to making the first Mars mission transit. The Mars Transit Habitat will utilize closed loop ECLS system technologies while a Mars Surface Habitat could use either open loop, closed loop, or a mix of both. Better understanding the needs of both these system architectures operating for extended periods in the Lunar environment and outside LEO will help to establish the ECLS system architecture for the future Mars surface mission. There are many aspects to consider such as length of crew stay, level of autonomy and dormancy between crewed missions, power requirements, system mass, and overall system reliability and maintainability. Other considerations will include Mars gravity vs. Lunar gravity, Mars atmospheric pressure vs. hard vacuum, and possible use of in-situ resource utilization.

ECLSS↗
NASA NTRS2023

An Investigation into the Effect of Liquid Accumulation on Thermo-Physiologic State using an Advanced Moisture Model Coupled with a High Resolution Human Thermal Model

A physics-based mathematical model for simulating heat and moisture transport on the skin and within clothing was developed to improve the accuracy of human thermal modeling predictions. In a previous study, a set of sweating hotplate experiments was specifically created to obtain test data for model validation. The clothing moisture model was subsequently coupled with a human thermal model and tested by simulating human experiments described in the open literature, which served to verify the model’s ability to predict whole body thermo-physiologic state in work-rest cycles during which sweating was known to occur. In this study, a human subject test was specifically designed to validate the model’s ability to predict local and whole body sweat evaporation and accumulation on the surface of the body. The human subject test incorporated twelve clothed male subjects of moderate physical fitness, ages 18-30, which were prescribed a work-rest cycle in a climate-controlled chamber (25 °C, 50% RH). Two activity levels were considered during the active stage (4 MET vs. 6.5 MET), and two sets of ending ambient conditions were considered for the final rest stage (25 °C vs. 15 °C, 50% RH). Model predictions were compared to the measured local skin temperatures, core temperatures, and whole body sweat losses. In general, the model was able to reproduce the trends observed in the human subject trial, but more importantly, provided insight into how dynamic changes in liquid content can impact the evolution of local and whole body thermo-physiologic state. This study demonstrates the ability of an advanced moisture model to capture distinct physics attributable to moisture accumulation, allowing for increased accuracy in predicting human thermal state and for interpreting the results of measurements derived from human subject tests.

human thermal model↗
NASA NTRSDate not supplied

In-Situ XRD/XRF to Support Life Detection on Mars

X-ray diffraction / X-ray fluorescence (XRD/XRF) analysis provides the most comprehensive mineralogical / compositional characterization of rocks and soils of any flight-capable technique. XRD data provide quantitative mineralogy (including abundance of X-ray amorphous materials) and crystal chemistry (structure, elemental composition and valence state), and XRF data provide complimentary major, minor, and some trace element abundances. Both types of data are important in evaluating habitability (environment of formation) and biosignature preservation/degradation (post-depositional diagenetic change). Whether or not a relict biosignature is detected, the mineral assemblage and its geochemistry can be used to determine the habitability of an ancient environment (e.g., salinity, pH, temperature), and to identify potential sources of energy for life (e.g., elements in different redox states). In this respect, a null result (a habitable environment lacking evidence of life) can play an important role in constraining the parameters of the search. Conversely, diagenetic alteration (taphonomic change) resulting from post-depositional variations in temperature, pressure or fluid chemistry can preserve evidence of biogenicity, erase such evidence completely or indeed can provide for post-depositional habitable conditions in the subsurface. XRD / XRF data are critical to these determinations. The CheMin instrument on the Mars Science Laboratory (MSL) Curiosity rover is the first XRD instrument flown in space. CheMin operates in transmission geometry with a Co X-ray source to minimize fluorescence from iron. Diffracted photons are collected with an energy-sensitive charge-coupled device (CCD). The position of the diffracted photons provides structural information for minerals, whereas the energy of sample-generated X-ray fluorescence photons provides elemental information, though these XRF data are qualitative. Mineralogical data from the CheMin XRD identified the three circumstances above: habitable depositional environments (e.g., Yellowknife Bay), habitable subsurface/diagenetic environments (e.g., throughout the Murray formation), and diagenetic conditions that may destroy evidence of habitability (e.g., oxidative and acidic environments at Vera Rubin ridge). Technological advances in X-ray technology and lessons learned from the operation of CheMin on Mars have resulted in a next-generation XRD/XRF, called CheMinX. Replacement of CheMin’s CCD with an array of hybrid pixel detectors and improvements in focusing optics dramatically decrease analysis time (15 minutes vs. 22 hours for MSL-CheMin) and result in a better angular resolution (0.18 vs. 0.30 °2θ for MSL-CheMin). This increased resolution improves mineral detection, including discrimination between types of pyroxenes, which is not possible with MSL-CheMin data. The hybrid pixel detectors do not require cooling like the MSL-CheMin CCD, therefore reducing the power needed to operate CheMinX. CheMinX has a silicon-drift detector (SDD) to measure fluoresced photons, enabling the quantification of major, minor, and some trace elements via XRF. XRD/XRF data are collected simultaneously in CheMinX, obviating the need for multiple compositional instruments. The CheMinX design also improves upon MSL-CheMin’s sample handling. Instead of sample cells on wheel, which are often not reusable and add complexity in commanding the instrument, CheMinX has single-use cells in a cartridge/dispenser configuration. Because of these improvements, CheMinX is an ideal instrument for Discovery-class life-detection missions, including Mars Life Explorer that was recommended for development in the Planetary Science and Astrobiology Decadal Survey 2023-2032.

E B Rampe↗
NASA NTRSDate not supplied

Phosphate (U-Th)/He Thermochronology of Apollo 14 Melt Breccia 14311

Our ability to confidently characterize the impact history of the inner solar system is limited by discrepancies in radiometric dates and age interpretations for lunar rocks, impact melts, and recovered meteorites. It is therefore important to explore different thermally sensitive radiometric systems to unravel the timing and extent of the long term impact flux. Low-temperature thermochronology of lunar samples has the potential to provide more complementary geochronological datasets and further test dynamical models related to the evolution of the inner solar system (e.g., [1]). (U-Th)/He dating is based on the production of 4He atoms by radioactive alpha decay of U and Th (and to a lesser extent, Sm) in a crystal and the thermally activated volumetric diffusion of those 4He nuclides. At high temperatures, the crystal is an open system from which 4He can escape; at lower temperatures, 4He may be retained. This retention temperature depends on factors such as crystal structure and volume fraction of radiation damage in the crystal (e.g., [2, 3]), but is significantly lower for phosphate minerals compared to the diffusion of the radiogenic daughter products in other widely used chronometric systems (e.g., ~75°C in terrestrial apatite (U-Th)/He vs. ~500°C in apatite U-Th-Pb vs. ~900°C in zircon U-Th-Pb chronometry). Phosphate (U-Th)/He dating has been used to decipher peak temperatures and cooling rates related to terrestrial impact events (e.g., [4]). Pairing a low-temperature thermochronometer with higher-temperature approaches (i.e., a combined 207Pb-206Pb and (U-Th)/He approach), can therefore resolve multiple impact ages within a given sample or even grain. However, despite its potential, phosphate (U-Th)/He dating has not been reported on any lunar samples. Here we present the first lunar phosphate (U-Th)/He thermochronology on an Apollo 14 impact melt-breccia.

C A Diaz↗
NASA NTRSDate not supplied

ISRU Pilot Excavator Wheel Testing in Lunar Regolith Simulant

The ISRU Pilot Excavator, or IPEx, is a robotic excavator funded by NASA’s Space Technology Mission Directorate (STMD). The Concept of Operations for IPEx involves the robot driving on the lunar surface up to 70 km at a speed of up to 30 cm/s. As such, it is critical to the mission’s success to optimize the design of the wheels for performance in lunar conditions, specifically in lunar regolith. To achieve this, an array of tests was completed to observe the effects of various wheel design choices on the driving performance of the wheels in lunar regolith simulant. In order to facilitate testing, we designed a 12” dia. configurable wheel to allow for interchangeability between various wheel formations. Two types of wheel parts were designed to be swapped: cleats, which form the tread of the wheel; and grousers, which protrude from the treads. The test variables that we considered were as follows: square vs. round wheel shape, solid vs. perforated cleats, cleat spacing, grouser height, and grouser spacing. By combining different settings of each of these test variables, ten discrete wheel designs were created and tested. The configurable test wheels were mounted on the Regolith Advanced Surface Systems Operations Robot (RASSOR) developed at NASA’s Kennedy Space Center. In our experiments, the robot was driven at a controlled speed across a prepared surface of BP-1 lunar regolith simulant. Four types of tests were conducted: circle driving, straight driving, slope driving, and drawbar pull. The driving tests were chosen to mimic a variety of conditions in which IPEx may be expected to operate, and the drawbar pull test was chosen to provide a standard of comparison with existing wheel design literature. The circle and straight driving tests were each performed at different levels: for the circle driving test, the robot was driven at a constant linear speed and three different angular speeds, while for the straight driving test, the robot was driven at three different linear speeds. The data collected from these tests included the power usage from each of the wheels, measurements of the tread patterns left in the regolith surface, and the amount of slip the wheels experienced, which was calculated using data from an OptiTrack motion capture system. From the results of these experiments, we found that certain test variables were more significant than others in determining performance for each type of test, and no single wheel design clearly outperformed the others in all areas. The details of our findings will be discussed further in this paper. This data will be utilized to inform the design of the wheels for IPEx and can provide a basis for the design of wheels for future lunar terrain vehicles.

RASSOR↗
NASA NTRS2024

An Integrated Architecture Study for Autonomous Lunar Construction

Lunar construction is an expanding field within NASA’s Moon to Mars objectives that presents many challenges and requires innovative and reliable forms of autonomous operations on the surface of the Moon to further the technologies needed for human space exploration. Marshal Space Flight Center’s (MSFC) Advanced Concepts Office (ACO) addressed Lunar Infrastructure Objective LI-4 l by developing a Pre-Phase A, integrated architecture to inform a demonstration for lunar construction operations. The ACO study traded three architectures that would survey and prepare a construction area to build a landing pad out of lunar regolith using MMPACT (Moon-to-Mars Planetary Autonomous Construction Technology) platforms, rovers, and navigation outposts. The main trades examined navigation for the system/architecture, options for rover navigation, battery vs continuous tether power for the MMPACT robotic arm, and assigning site prep functionality to the rovers vs the platforms. Results of the study determined that the best options for the scenario provided would be local navigation (more accurate and continuous), a combination of Light Detection and Ranging (LiDAR) for initial site mapping with subsequent Smart Video Guidance Sensors (SVGS) to save power for construction, and using tethered power to decrease mission duration. The team also concluded that assigning site prep functionality to either the rovers or the platforms has benefits and challenges; future studies could explore having that functionality on both the rovers and platforms. Lastly, the team provided a Concept of Operations (ConOps) timeline that can be used in real-time ground demonstrations to explore the mission timeline, construction processes, autonomous operations, and communication systems that can be tested using MSFC’s lunar regolith field and Lunar Utilization Control Area (LUCA).

Sarah Triana↗
NASA NTRSDate not supplied

All-Climate and Ultrafast Rechargeable Aluminum Batteries Enabled By Ternary Eutectic Electrolytes

For Rechargeable Aluminum Batteries (RABs), electrolytes emerge as the most crucial and decisive component due to the following aspects: (i) Sluggish reaction kinetics due to high gravimetric density of Al (2.70 g/cm 3 vs. 0.53 g/cm 3 for Li) and high surface charge density, (ii) a limited safe potential window owing to moderate standard redox potential values. The state-of-the-art electrolytes in the field exhibits a limited stability window (<2.6V vs. Al/Al +3 ), leading to undesired side reactions, such as Cl 2 gas generation, and self-discharge in RABs. Exploration of RABs low-temperature performance is restricted by electrolyte limitations.

Raju Vadthya↗
NASA NTRSDate not supplied

Development of a Safety Hazards Risk Assessment Tool for Uncrewed Aircraft System Traffic Management during Preflight Planning

Tremendous growth in the uncrewed and remotely piloted vehicle market is expected in low-altitude, uncontrolled airspace, resulting in potential decreases in safety without systems that support monitoring, assessing, and mitigating risk. At NASA, the System-Wide Safety (SWS) project has been developing a suite of data-driven tools to predict hazards so that the potential risks that these hazards pose can be mitigated. Services to predict various hazards have been developed, including battery capacity, proximity to static obstacles, population risks, global positioning system signal strength, radio frequency spectrum interference risk, and vertiport congestion. These services can monitor hazards along a flight path and if any risks posed by these hazards exceed a threshold, the uncrewed aircraft system (UAS) fleet manager can be alerted to mitigate the risk by modifying the flight path, changing the scheduled departure or arrival times, and/or diverting the vehicle to an alternate vertiport. These services were originally developed to monitor and assess risks during flight, but they have been adapted to assess hazard risks prior to departure so that a fleet manager can evaluate the potential risks for a fleet of UAS along their planned flight paths. These services have been integrated into a prototype tool called the Supplemental Data Service Provider-Consolidated Dashboard (SDSP-CD), developed at NASA Ames Research Center. The tool consists of a dashboard which provides a comprehensive overview for a number of risks and a map display that shows the details of the hazards along each flight’s path. Based on the findings from three previous studies, the SDSP-CD has been updated with new design elements and functions. In this paper, we describe lessons learned from the previous studies, changes made to the interface, and the feedback received during a follow-up usability study. Overall, participants reported that there is a substantial benefit of having a fleet manager use a consolidated dashboard to assess hazards for the vehicles in their fleet and to provide situational awareness to potential risks so that they can be mitigated prior to flight. Once the SDSP-CD matures, it will need to be integrated into flight and mission planning tools. Some initial thoughts on how this integration should be accomplished are shared in this paper. Finally, the functional differences between preflight vs. in-flight risk assessment and the differences in fleet manager vs. UAS pilot roles that may require different information and user interactions are discussed.

preflight↗
NASA NTRS2026

Effects of Multisensory Virtual Reality Nature on Affect, Presence, and Restorativeness

Virtual reality (VR) can provide access to restorative environments and sensory stimulation for individuals in isolated, confined, and extreme environments. We developed a nature-based VR intervention featuring three scenes (Garden, Forest, Beach) and examined the effects of multisensory augmentation with location-based olfactory, wind, and thermal stimuli (VR+OWT). Over a two-week period, fifty-one participants were assigned to a no-intervention control, standard audiovisual VR, or augmented VR (VR+OWT) condition. Data collection included weekly assessments of affect, stress, and cognitive performance; post-VR measures of affect, presence, and perceived restorativeness; and open-ended feedback. Both VR and VR+OWT groups produced immediate and sustained reductions in negative affect with no sustained systematic benefits on cognitive performance. The addition of olfactory, wind, and thermal stimuli enhanced presence for some scenes; however, feedback indicated that sensory mismatches and stimulus intensity occasionally detracted from the experience and may have contributed to lower coherence ratings in the VR+OWT group. In contrast, the perceived restorativeness of the VR environment was driven primarily by scene content (Garden vs Forest vs Beach) rather than the level of sensory stimulation. These findings support the potential of virtual nature to promote well-being and underscore the importance of coherence across sensory modalities for multisensory augmentation.

Virtual Reality Intervention↗