Results for “considerations” — Page 33

NASA NTRSDate not supplied

Considerations for Health and Performance During Surface Extravehicular Activities

BACKGROUND: NASA’s objectives for expanding human presence beyond low Earth orbit will require Extravehicular Activities (EVAs) on lunar and planetary surfaces. Given the physiological and functional demands of conducting surface EVAs in a pressurized spacesuit in reduced gravity environments, there is a possibility that crew injury and compromised physiological and/or functional performance may present. OVERVIEW: Many human health and performance knowledge gaps exist in regards to exploration EVA that require characterization to ensure safety, reliability, and mission success. To address knowledge gaps, EVA simulations in Earth-based analog environments and/or spacesuit simulators can be utilized to provide valuable insights into task-based physiologic and metabolic costs, cognitive loads, and associated operational limitations to inform future mission concepts. Physical workloads approaching 60% of maximum metabolic rates and 85% age-predicted heart rate maxima; core body temperatures approaching 100o F; and subjective responses indicating limited spare cognitive capacity via Bedford scale have been observed during ground-based exploration EVA simulations in the NASA Active Response Gravity Offload Simulator (ARGOS) and Neutral Buoyancy Lab (NBL) during simulated planetary EVAs in pressurized suits. Further, ground-based EVA analogs vary in their ability to simulate planetary EVA and resulting physical workloads. DISCUSSION: Metabolic costs, thermal burdens, functional strength, and cognitive impacts have been and must continue to be assessed in ground-based analogs to fully characterize operational demands and crew readiness levels for exploration EVA. Considerations should be given to enabling a new concept of high-tempo surface EVA operations and associated work-rest intervals, understanding human health and performance impacts of evolving commercial suit designs and capabilities, and predictive modeling and decision support capabilities to enable safe and successful EVA operations.

EVA↗

NASA NTRS2024

Considerations in Range of Motion Testing for Characterizing Spacesuit Mobility Capabilities

Mobility is a critical aspect for spacesuits as it directly influences how astronauts can perform tasks safely and efficiently, while wearing the pressurized suit. Spacesuit motion is dissimilar to human movement and consists of unique movement patterns as result of pressurization and the complex mechanical joint configurations. Thus, it is important to quantify the variations in suited movement patterns and the resulting performance of the wearer for the evaluation of the spacesuit itself and hardware interfaces such as payloads and tools. Traditionally, an individual body joint is assessed for the segment-wise range of motion. For example, the knee is measured through an isolated maneuvering of the joint between the max-to-max positions (e.g., flexion/extension), and the outcome represents the mobility capabilities. These measurements are often conducted using optical motion capture system with respect to anatomical planes. However, there are several considerations for range of motion assessments that are unique to the spacesuit. The purpose of this paper is to describe and provide examples of these additional challenges in representing spacesuit mobility capabilities. Specifically, joint mobility and the variations in suit movement patterns were investigated and compared between functional tasks and isolated range of motion measurements. Motion capture data from the next-gen spacesuit design verification testing was evaluated to compare isolated range of motion tasks to functional tasks, such as one-knee kneeling and squatting. The trajectories from the upper and lower body joint centers with respect to the spacesuit hardware were also calculated. Additionally, the joint trajectories for various functional tasks are presented and compared against the isolated range of motion measurements. In general, range of motion differs between isolated and functional tasks, where functional tasks may even induce greater joint angle excursions. Additionally, there is a large variation in joint range of motion across functional tasks. Combined with several relevant factors (spacesuit fit, physical strength, simulation facility, etc.), spacesuit mobility characterization efforts will need to incorporate the specific contexts, such as task demands and movement mechanisms, when evaluating range of motion assessments.

Linh Q Vu↗

NASA NTRSDate not supplied

Optimization Considerations for Annular Linear Electromagnetic Pumps for Space Nuclear Power and Propulsion

The Need for High Performance Liquid Metal Pumps Testing Power and Efficiency Considerations Liquid metal cooled reactors is one option for space nuclear power for settlements and electric propulsion vehicles (Snap 10 A, SP100, Soviet Topaz reactors) • High heat capacity • High boiling point (NaK~1200K) • Simplified heat transfer loop • Good neutronics Liquid metal EM pumps are desired over conventional pumps owing to lack of seals, bearings elimination of cavitation issues, lower mass and eliminates mechanical impeller • Conduction pumps (typically DC-high current, low voltage; ~5% efficiency) • Induction pumps (typically AC, high efficiency ~40%) Annular linear induction pump is an EM pump with no moving parts and of cylindrical/tubular geometry which makes it straightforward to integrate in conventional piping architectures • Higher inherent reliability • Invented by Einstein and Szilard

ALIP↗

NASA NTRSDate not supplied

Considerations For Aerospace Vehicle Design: Systems, Structures And Materials

The speaker will provide an overview and some perspective on the systems engineering and conceptual design of launch vehicles and other aerospace systems. The strong interactions and relationships between systems requirements, cost, schedule, performance, risk, reliability and margins are explored in the context of vehicle design. Systems-level considerations for selection of structures and materials are also presented and discussed. Relevant examples from aerospace history are used to illustrate key concepts.

systems engineering↗

NASA NTRS2024

Engineering A Bridge Across Cultures: Insights to Support Dialogue with Engineering Professionals on Ethical and Social Design Considerations

In April 2023, the National Aeronautics and Space Administration (NASA) hosted the Artemis and Ethics workshop at NASA headquarters, inviting 55 participants from a wide range of scholarly disciplines to participate in a dialogue on ethical considerations for Artemis and the Moon to Mars initiative. At this event, participants identified a set of challenges in engaging the ethical and social implications of these missions. This paper seeks to further explore those concepts from the workshop report and provide insights on how to discuss the design implications of engineering leadership decisions and to elicit meaningful engagement on these topics. This analysis can inform future research and educational approaches and help ethics and social science researchers to engage engineering and project leaders in constructive dialogue.

Artemis↗

NASA NTRS2024

Considerations for Health and Performance during Surface Extravehicular Activities

BACKGROUND: NASA’s objectives for expanding human presence beyond low Earth orbit will require Extravehicular Activities (EVAs) on lunar and planetary surfaces. Given the physiological and functional demands of conducting surface EVAs in a pressurized spacesuit in reduced gravity environments, there is a possibility that crew injury and compromised physiological and/or functional performance may present. OVERVIEW: Many human health and performance knowledge gaps exist in regards to exploration EVA that require characterization to ensure safety, reliability, and mission success. To address knowledge gaps, EVA simulations in Earth-based analog environments and/or spacesuit simulators can be utilized to provide valuable insights into task-based physiologic and metabolic costs, cognitive loads, and associated operational limitations to inform future mission concepts. Physical workloads approaching 60% of maximum metabolic rates and 85% age-predicted heart rate maxima; core body temperatures approaching 100° F; and subjective responses indicating limited spare cognitive capacity via Bedford scale have been observed during ground-based exploration EVA simulations in the NASA Active Response Gravity Offload Simulator (ARGOS) and Neutral Buoyancy Lab (NBL) during simulated planetary EVAs in pressurized suits. Further, ground-based EVA analogs vary in their ability to simulate planetary EVA and resulting physical workloads. DISCUSSION: Metabolic costs, thermal burdens, functional strength, and cognitive impacts have been and must continue to be assessed in ground-based analogs to fully characterize operational demands and crew readiness levels for exploration EVA. Considerations should be given to enabling a new concept of high-tempo surface EVA operations and associated work-rest intervals, understanding human health and performance impacts of evolving commercial suit designs and capabilities, and predictive modeling and decision support capabilities to enable safe and successful EVA operations.

P Estep↗

NASA NTRS2024

Advanced Pressure Garment Space Suit Sizing Considerations

Fitting a space suit to a person could be considered an art form. Establishing a repeatable fitcheck process to accommodate the full anthropometric range of test subjects for a single suit design is a critical process to be able to prove suit functionality. Suited test subjects can have different preferences on how they fit inside a suit, and different suited test environments can lead to differences in certain suit sizing accommodations. Throughout this paper, the process of achieving an acceptable suit fit for test subjects will be discussed, along with sizing considerations for changes in suit design and test environments. Lessons learned from the Exploration Extravehicular Mobility Unit (xEMU) will be used to describe specific examples, along with key takeaways from additional NASA prototype mobility space suits. The suit fitcheck process starts with utilizing the anthropometric measurements of a test subject to evaluate their relation to the dimensions of space suit hardware in creating a predicted suit sizing configuration. From here, subjective comments and test team observations drive iterations to the suit sizing configuration to culminate in an acceptable suit fit for performance of further test evaluations. Understanding the relation of subjective comments to their impact on altering suit sizing is critical in establishing an acceptable suit fit.

spacesuit↗

NASA NTRSDate not supplied

Radiation Effects Considerations for Instrumentation and Control in Space Nuclear Systems

Radiation effects in electrical, electronic, electro-motive, and electro-optical (EEEE) hardware encompass a complex variety of interactions, processes, environments, and an evolving landscape of relevant hardware. Appropriately mitigating the effects of radiation in sensors, data acquisition, and control hardware is among the most significant challenges associated with deploying space nuclear power and propulsion systems. The expertise within EEEE radiation effects disciplines require working knowledge that is at least as complex and diverse as the problem itself, but that should not dissuade stakeholders and engineers in adjacent disciplines from attempting to understand the general principles associated with the problem at hand. This brief overview seeks to bring to the foreground a set of relevant topics that are of special importance for space nuclear propulsion applications that involve high rates of neutron and gamma radiation. The unique set of environments and design requirements for space nuclear systems mean that the experience and utility for methods applied to typical spaceflight hardware or terrestrial nuclear systems must not be applied naively. Forward consideration on the applicability of testing methods applied to either existing or bespoke hardware is likely to drive early decisions on system-wide radiation effects mitigation strategies, and will influence procurement requirements for providers of radiation tolerant hardware who are unlikely to have experience in this unique set of environments. Radiation hardness assurance (RHA) guidance should be adapted and emphasize the importance of hardware testing in the relevant environment. These must consider the combined effects of temperature, total ionizing dose (TID), non-ionizing/displacement damage (TNID/DD), and single event effects (SEE), and should consider the impacts of flux (rate) in addition to cumulative effects.

Radiation↗

NASA NTRSDate not supplied

Considerations for Range of Motion Testing During Spacesuit Mobility Characterization

Mobility is a critical aspect for spacesuits as it directly influences how astronauts can perform tasks safely and efficiently, while wearing the pressurized suit. Spacesuit motion is dissimilar to human movement and consists of unique movement patterns as result of pressurization and the complex mechanical joint configurations. Thus, it is important to quantify the variations in suited movement patterns and the resulting performance of the wearer for the evaluation of the spacesuit itself and hardware interfaces such as payloads and tools. Traditionally, an individual body joint is assessed for the segment-wise range of motion. For example, the knee is measured through an isolated maneuvering of the joint between the max-to-max positions (e.g., flexion/extension), and the outcome represents the mobility capabilities. These measurements are often conducted using optical motion capture system with respect to anatomical planes. However, there are several considerations for range of motion assessments that are unique to the spacesuit. The purpose of this paper is to describe and provide examples of these additional challenges in representing spacesuit mobility capabilities. Specifically, joint mobility and the variations in suit movement patterns were investigated and compared between functional tasks and isolated range of motion measurements. Motion capture data from the next-gen spacesuit design verification testing was evaluated to compare isolated range of motion tasks to functional tasks, such as one-knee kneeling and squatting. The trajectories from the upper and lower body joint centers with respect to the spacesuit hardware were also calculated. Additionally, the joint trajectories for various functional tasks are presented and compared against the isolated range of motion measurements. In general, range of motion differs between isolated and functional tasks, where functional tasks may even induce greater joint angle excursions. Additionally, there is a large variation in joint range of motion across functional tasks. Combined with several relevant factors (spacesuit fit, physical strength, simulation facility, etc.), spacesuit mobility characterization efforts will need to incorporate the specific contexts, such as task demands and movement mechanisms, when evaluating range of motion assessments.

Linh Q Vu↗

NASA NTRSDate not supplied

Advanced Space Suit Sizing Considerations

Fitting a space suit to a person could be considered an art form. Establishing a repeatable fitcheck process to accommodate the full anthropometric range of test subjects for a single suit design is a critical process to be able to prove suit functionality. Suited test subjects can have different preferences on how they fit inside a suit, and different suited test environments can lead to differences in certain suit sizing accommodations. Throughout this paper, the process of achieving an acceptable suit fit for test subjects will be discussed, along with sizing considerations for changes in suit design and test environments. Lessons learned from the Exploration Extravehicular Mobility Unit (xEMU) will be used to describe specific examples, along with key takeaways from additional NASA prototype mobility space suits. The suit fitcheck process starts with utilizing the anthropometric measurements of a test subject to evaluate their relation to the dimensions of space suit hardware in creating a predicted suit sizing configuration. From here, subjective comments and test team observations drive iterations to the suit sizing configuration to culminate in an acceptable suit fit for performance of further test evaluations. Understanding the relation of subjective comments to their impact on altering suit sizing is critical in establishing an acceptable suit fit.

spacesuit↗

NASA NTRS2024

Considerations for Using Autonomous Flight Termination Software in Crewed Launch Vehicles

Autonomous flight termination systems (AFTS) are being progressively employed onboard launch vehicles to replace ground personnel and infrastructure needed to terminate flight or destruct the vehicle should an anomaly occur. This automation uses on-board real-time data and encoded logic to determine if the flight should be self-terminated. For uncrewed launch vehicles, FTS systems are required to protect the public and governed by the United States Space Force (USSF). For crewed missions, NASA must augment range AFTS requirements for crew safety and certify each flight according to human rating standards, thus adding unique requirements for reuse of software originally intended for uncrewed missions. This bulletin summarizes new information relating to AFTS to raise awareness of key distinctions, summarize considerations and outline best practices for incorporating AFTS into human-rated systems.

Avionics↗

NASA NTRSDate not supplied

Design Considerations for Aerocapture Delivery of Uranus Orbiter and Probe

This paper presents an aerocapture system design for delivering the Uranus Orbiter and Probe (UOP) subsystems to their science orbit using the Mars Science Laboratory architecture. A packaging and integration scheme are presented for UOP subsystems, with careful consideration of large components required for outer planet science missions (RTG power generation, RF communications). The implication of packaging multiple RTG’s inside an aeroshell during a multiple year cruise phase will be explained, with possible thermal design solutions to mitigate RTG waste heat analyzed. Mass properties and margins for the system are discussed and an overall mass risk assessment is presented for the entry system and total flight system at launch. Alternative vehicle configurations are explored to include multiple probes and enable science objectives during transit to Uranus. Aerocapture mass savings when compared to the baseline UOP design are presented.

Andrew J. Gomez-Delrio↗

NASA NTRSDate not supplied

Practical Considerations using Weighted-Acceleration Compensation Techniques for Dynamic Force Measurements in Wind Tunnels

Most wind tunnel force measurement systems are designed and calibrated for high-accuracy static measurements, but may have limited ability to sense dynamic forces and moments. As a means to improve the measurement bandwidth of dynamic forces, researchers have proposed using a weighted-acceleration technique, which uses accelerometer data to compensate and correct for system dynamics. The sum of weighted-accelerations method is attractive as the acceleration data applies a correction to the traditional static measurements. The focus of this paper is on practical aspects of implementing a weighted-acceleration technique in an experimental arrangement. A formulation of the weighted-acceleration methodology is validated on a reduced-order model and demonstrated on a tabletop experiment that serves as a proxy to a wind tunnel force measurement system. As part of this system, a two component normal force and pitching moment balance was designed and fabricated. A static and dynamic calibration of the system was performed, and the weighted-acceleration technique was used to reconstruct impact forces acting on the system. Practical considerations of the experimental design that improve the success of the methodology are discussed.

Dynamic force measurement↗

NASA NTRSDate not supplied

BioNutrients Bioreactors: Design and Materials Considerations for Synthetic Biology

The BioNutrients project aims to develop an on-demand biological production system capable of producing dietary nutrients and other products of interest. A key element of this system is the bioreactor itself, which needs to provide a suitable environment for growth of the selected microorganism(s). To support respiration of the organisms, the bioreactor should have gas-permeable elements to allow metabolically required gases (e.g., oxygen) to enter and byproduct gases (e.g., carbon dioxide) to escape. For systems utilizing yeast for precision fermentation, the system also needs to prevent or minimize the release of ethanol, which has impacts on the Environmental Control and Life Support System (ECLSS). Additionally, the bioreactor must include interfaces for hydrating the microorganism(s), sampling, and crew interface. For experiments on the International Space Station (ISS), the bioreactor must also comply with ISS-levied offgassing, cold stowage, and other safety requirements. This presentation aims to explore these design considerations, using the examples of the bioreactors used for the BioNutrients ISS payload series.

vitamins↗

NASA NTRSDate not supplied

Design Considerations for Aerocapture Delivery of Uranus Orbiter and Probe

This paper presents an aerocapture system design for delivering the Uranus Orbiter and Probe (UOP) subsystems to their science orbit using the Mars Science Laboratory architecture. A packaging and integration scheme are presented for UOP subsystems, with careful consideration of large components required for outer planet science missions (RTG power generation, RF communications). The implication of packaging multiple RTG’s inside an aeroshell during a multiple year cruise phase will be explained, with possible thermal design solutions to mitigate RTG waste heat analyzed. Mass properties and margins for the system are discussed and an overall mass risk assessment is presented for the entry system and total flight system at launch. Alternative vehicle configurations are explored to include multiple probes and enable science objectives during transit to Uranus. Aerocapture mass savings when compared to the baseline UOP design are presented.

Aerocapture↗

NASA NTRSDate not supplied

Practical Considerations using Weighted-Acceleration Compensation Techniques for Dynamic Force Measurements in Wind Tunnels

Most wind tunnel force measurement systems are designed and calibrated for high-accuracy static measurements, but may have limited ability to sense dynamic forces and moments. As a means to improve the measurement bandwidth of dynamic forces, researchers have proposed using a weighted-acceleration technique, which uses accelerometer data to compensate and correct for system dynamics. The sum of weighted-accelerations method is attractive as the acceleration data applies a correction to the traditional static measurements. The focus of this paper is on practical aspects of implementing a weighted-acceleration technique in an experimental arrangement. A formulation of the weighted-acceleration methodology is validated on a reduced-order model and demonstrated on a tabletop experiment that serves as a proxy to a wind tunnel force measurement system. As part of this system, a two component normal force and pitching moment balance was designed and fabricated. A static and dynamic calibration of the system was performed, and the weighted-acceleration technique was used to reconstruct impact forces acting on the system. Practical considerations of the experimental design that improve the success of the methodology are discussed.

Dynamic force measurement↗

NASA NTRSDate not supplied

Considerations for High-Speed Background-Oriented Schlieren Visualization Capability for Ground Test Facilities

Since its introduction in the year 2000, background-oriented schlieren (BOS) has become a cornerstone technique for visualizing variable-density flows. In this review, we provide a rigorous examination of the optical principles underpinning BOS and related refractive-index-based techniques, complemented by an appendix linking schlieren imaging to Maxwell’s equations. The core sections delve into the practical aspects of BOS, with detailed discussions on image processing algorithms and critical considerations for experimental setups. We then explore recent advancements and innovations, including extensions of BOS with tomography, data assimilation, and event-based imaging. Finally, we present notable applications of BOS in challenging and unconventional environments, showcasing the method’s versatility and offer inspiration for future research directions.

Brett Bathel↗

NASA NTRSDate not supplied

Multifaceted Considerations for Fission Surface Power Radiation Shielding Design

The purpose of the Fission Surface Power (FSP) nuclear system is to provide energy on the Moon and Mars for supporting their exploration and colonization. The FSP design and deployment can leverage the past research and development work in areas, such as reactor design, but such crucial components as radiation shielding and instrumentation still need material and manufacturing studies, modeling, and testing. The shielding components are needed for the protection of humans, electronics, and sensitive components. They are essential system components, but they are often the heaviest components of the system for which each kilogram matters. Different material combinations and layouts are possible. The studies presented were focused on the evaluation of several options. The initial analysis included their performance assessment, initial temperature distribution evaluation and manufacturability considerations. Several feasible shield design options were identified and discussed in this paper, as well.

Fission Surface Power↗