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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

A Comparison of Transportation Systems for Human Missions to Mars

There are many ways to send humans to Mars. Credible technical reports can be traced to the 1950's. More recently, NASA has funded major studies that depict a broad variety of trajectories, technologies, stay times, and costs. Much of this data is still valid with direct application to today's exploration planning. This paper presents results comparing these studies with particular emphasis on the in-space transportation aspects of the mission. Specifically, comparisons are made on propulsion systems used for getting the crew and mission equipment from Earth orbit to Mars orbit, descending and ascending from the surface, and returning to Earth orbit. Areas of comparison for each of these phases include crew size, mission mass, propellant mass, delta v, specific impulse, transit time, surface stay time, aero-braking, and others. Data is analyzed to demonstrate either strong trends toward particular technologies or diverging solutions.

Bipropellants↗
NASA NTRS1998

Influence of gravity on cardiac performance

Results obtained by the investigators in ground-based experiments and in two parabolic flight series of tests aboard the NASA KC-135 aircraft with a hydraulic simulator of the human systemic circulation have confirmed that a simple lack of hydrostatic pressure within an artificial ventricle causes a decrease in stroke volume of 20%-50%. A corresponding drop in stroke volume (SV) and cardiac output (CO) was observed over a range of atrial pressures (AP), representing a rightward shift of the classic CO versus AP cardiac function curve. These results are in agreement with echocardiographic experiments performed on space shuttle flights, where an average decrease in SV of 15% was measured following a three-day period of adaptation to weightlessness. The similarity of behavior of the hydraulic model to the human system suggests that the simple physical effects of the lack of hydrostatic pressure may be an important mechanism for the observed changes in cardiac performance in astronauts during the weightlessness of space flight.

NASA Discipline Cardiopulmonary↗
NASA NTRS2006

Incorporating Research Findings into Standards and Requirements for Space Medicine

The Vision for Exploration has been the catalyst for NASA to refocus its life sciences research. In the future, life sciences research funded by NASA will be focused on answering questions that directly impact setting physiological standards and developing effective countermeasures to the undesirable physiological and psychological effects of spaceflight for maintaining the health of the human system. This, in turn, will contribute to the success of exploration class missions. We will show how research will impact setting physiologic standards, such as exposure limits, outcome limits, and accepted performance ranges. We will give examples of how a physiologic standard can eventually be translated into an operational requirement, then a functional requirement, and eventually spaceflight hardware or procedures. This knowledge will be important to the space medicine community as well as to vehicle contractors who, for the first time, must now consider the human system in developing and constructing a vehicle that can achieve the goal of success.

Duncan, J. Michael↗
NASA NTRS2014

Concepts to Support HRP Integration Using Publications and Modeling

Initial efforts are underway to enhance the Human Research Program (HRP)'s identification and support of potential cross-disciplinary scientific collaborations. To increase the emphasis on integration in HRP's science portfolio management, concepts are being explored through the development of a set of tools. These tools are intended to enable modeling, analysis, and visualization of the state of the human system in the spaceflight environment; HRP's current understanding of that state with an indication of uncertainties; and how that state changes due to HRP programmatic progress and design reference mission definitions. In this talk, we will discuss proof-of-concept work performed using a subset of publications captured in the HRP publications database. The publications were tagged in the database with words representing factors influencing health and performance in spaceflight, as well as with words representing the risks HRP research is reducing. Analysis was performed on the publication tag data to identify relationships between factors and between risks. Network representations were then created as one type of visualization of these relationships. This enables future analyses of the structure of the networks based on results from network theory. Such analyses can provide insights into HRP's current human system knowledge state as informed by the publication data. The network structure analyses can also elucidate potential improvements by identifying network connections to establish or strengthen for maximized information flow. The relationships identified in the publication data were subsequently used as inputs to a model captured in the Systems Modeling Language (SysML), which functions as a repository for relationship information to be gleaned from multiple sources. Example network visualization outputs from a simple SysML model were then also created to compare to the visualizations based on the publication data only. We will also discuss ideas for building upon this proof-of-concept work to further support an integrated approach to human spaceflight risk reduction.

Mindock, J.↗
NASA NTRSDate not supplied

Brace For Impact – It’s Coming, Do You Know What to Do With It?

Long-duration human exploration spaceflight missions to the Moon and Mars present unprecedented challenges for providing in-mission medical care. Compared with the International Space Station, the greater distance from Earth will mean increased mission durations, communication delays, limited to no resupply opportunities, and significant limitations on the evacuation of ill or injured crew. Spacecraft mass, volume, and power will be curtailed while higher demands will be placed on the crew’s knowledge, skills, and abilities. In this higher risk environment, it is important to define and quantitatively estimate human system risk attributable to medical conditions. IMPACT (Informing Mission Planning via Analysis of Complex Tradespaces) is a probabilistic risk assessment (PRA) and medical trade space analysis tool being developed by NASA to advance medical system design for exploration missions. IMPACT has made a number of enhancements on the Integrated Medical Model, the PRA tool currently used by NASA. These updates include a novel medical evidence base baselined to a long duration, deep space exploration environment; an expanded medical condition list; and a trade space analysis capability (e.g. comparing risk profiles and mass/volume constraints for medical capabilities and resources). IMPACT core functionality includes quantification of a medical capability set and assisting with identification of specific medical resources/hardware for exploration missions. In addition, IMPACT provides sophisticated trade space capabilities to estimate how human system risk varies with changes to the mission architecture or medical capability set. This presentation will provide a brief overview of the IMPACT tool, discuss representative use cases, and show example results.

Benjamin Easter↗
NASA NTRS2019

Challenges in applying model-based systems engineering: human-centered design perspective

Systems engineering is, by its nature, human-centered. It is about tradeoffs and negotiations by systems engineers among different disciplines and systems to ensure the resulting system of systems can achieve the mission objectives successfully. Applying MBSE means enabling system engineers to use MBSE processes, methods, and tools to perform such work. This requires not only tools and infrastructure that support MBSE but also cultural change in how system engineers approach their work. Although the cultural change is listed as one of the challenges for MBSE infusion to address, its details and how to address them are not often discussed in the literature and the community. We used Human-Centered Design framework to articulate a core set of related challenges and the implications to tool and infrastructure developments. We will discuss the details of the HCD framework applied and discuss the core challenges using an electrical system engineering to harness engineering workflow as a case study.

Jimenez, Alejandro↗
NASA NTRS1992

Design for interaction between humans and intelligent systems during real-time fault management

Initial results are reported to provide guidance and assistance for designers of intelligent systems and their human interfaces. The objective is to achieve more effective human-computer interaction (HCI) for real time fault management support systems. Studies of the development of intelligent fault management systems within NASA have resulted in a new perspective of the user. If the user is viewed as one of the subsystems in a heterogeneous, distributed system, system design becomes the design of a flexible architecture for accomplishing system tasks with both human and computer agents. HCI requirements and design should be distinguished from user interface (displays and controls) requirements and design. Effective HCI design for multi-agent systems requires explicit identification of activities and information that support coordination and communication between agents. The effects are characterized of HCI design on overall system design and approaches are identified to addressing HCI requirements in system design. The results include definition of (1) guidance based on information level requirements analysis of HCI, (2) high level requirements for a design methodology that integrates the HCI perspective into system design, and (3) requirements for embedding HCI design tools into intelligent system development environments.

Malin, Jane T.↗
NASA NTRS2008

Derivation of Boundary Manikins: A Principal Component Analysis

When designing any human-system interface, it is critical to provide realistic anthropometry to properly represent how a person fits within a given space. This study aimed to identify a minimum number of boundary manikins or representative models of subjects anthropometry from a target population, which would realistically represent the population. The boundary manikin anthropometry was derived using, Principal Component Analysis (PCA). PCA is a statistical approach to reduce a multi-dimensional dataset using eigenvectors and eigenvalues. The measurements used in the PCA were identified as those measurements critical for suit and cockpit design. The PCA yielded a total of 26 manikins per gender, as well as their anthropometry from the target population. Reduction techniques were implemented to reduce this number further with a final result of 20 female and 22 male subjects. The anthropometry of the boundary manikins was then be used to create 3D digital models (to be discussed in subsequent papers) intended for use by designers to test components of their space suit design, to verify that the requirements specified in the Human Systems Integration Requirements (HSIR) document are met. The end-goal is to allow for designers to generate suits which accommodate the diverse anthropometry of the user population.

Young, Karen↗
NASA NTRS1970

Human Factors Systems SRT

Man machine concepts for remote control of unmanned planetary and lunar roving vehicles

Source record↗
NASA NTRS1972

Dosimetry for radiobiological studies of the human hematopoietic system

A system for estimating individual bone marrow doses in therapeutic radiation exposures of leukemia patients was studied. These measurements are used to make dose response correlations and to study the effect of dose protraction on peripheral blood cell levels. Three irradiators designed to produce a uniform field of high energy gamma radiation for total body exposures of large animals and man are also used for radiobiological studies.

Beck, W. L.↗
NASA NTRS1972

The study of human venous system dynamics using hybrid computer modeling

A computer-based model of the cardiovascular system was created emphasizing effects on the systemic venous system. Certain physiological aspects were emphasized: effects of heart rate, tilting, changes in respiration, and leg muscular contractions. The results from the model showed close correlation with findings previously reported in the literature.

Snyder, M. F.↗
NASA NTRS1983

A study on airborne integrated display system and human information processing

The cognitive behavior of pilots was examined in an experiment involving mock ups of an eight display electronic attitude direction indicator for an airborne integrated display. Displays were presented in digital, analog digital, and analog format to experienced pilots. Two tests were run, one involving the speed of memorization in a single exposure and the other comprising two five second exposures spaced 30 sec apart. Errors increased with the speed of memorization. Generally, the analog information was assimilated faster than the digital data, with regard to the response speed. Information processing was quantified as 25 bits for the first five second exposure and 15 bits during the second.

Mizumoto, K.↗
NASA NTRS1985

The human cardiovascular system in the absence of gravity

The data collected from a Space Shuttle crew to investigate cardiovascular changes due to microgravity are presented. The experimental procedures which involved preflight, immediate postflight, and one week following postflight echocardiograms of 13 individuals are described. The immediate postflight results reveal a 20 percent decrease in stroke volume, a 16 percent decrease in left ventricular diastolic volume index (LVDVI), no change in systolic volume, blood pressure, or cardiac index, and a 24 percent increase in heart rate. One week later a 17 percent stroke volume increase, a 29 percent increase in cardiac index, and normal blood pressure, and LVDVI were observed. It is concluded that upon reexposure to gravity a readaptation process for the cardiovascular system occurs.

Bungo, M. W.↗