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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Radiation Risk Projections for Space Travel

Space travelers are exposed to solar and galactic cosmic rays comprised of protons and heavy ions moving with velocities close to the speed of light. Cosmic ray heavy ions are known to produce more severe types of biomolecular damage in comparison to terrestrial forms of radiation, however the relationship between such damage and disease has not been fully elucidated. On Earth, we are protected from cosmic rays by atmospheric and magnetic shielding, and only the remnants of cosmic rays in the form of ground level muons and other secondary radiations are present. Because human epidemiology data is lacking for cosmic rays, risk projection must rely on theoretical understanding and data from experimental models exposed to space radiation using charged particle accelerators to simulate space radiation. Although the risks of cancer and other late effects from cosmic rays are currently believed to present a severe challenge to space travel, this challenge is centered on our lack of confidence in risk projections methodologies. We review biophysics and radiobiology data on the effects of the cosmic ray heavy ions, and the current methods used to project radiation risks . Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Risk projections for space travel are described using Monte-Carlo sampling from subjective error di stributions that represent the lack of knowledge in each factor that contributes to the projection model in order to quantify the overall uncertainty in risk projections. This analysis is applied to space mi ssion scenarios including lunar colony, deep space outpost, and a Mars mission. Results suggest that the number of days in space where cancer mortality risks can be assured at a 95% confidence level to be below the maximum acceptable risk for radi ation workers on Earth or the International Space Station is only on the order of 100-200 days. Approaches to reduce these unceI1ainties and mitigate risks are described.

Cucinotta, Francis↗
NASA NTRS2016

Results of the Lunar Exploration Analysis Group (LEAG) Gap Review: Specific Action Team (SAT), Examination of Strategic Knowledge Gaps (SKGs) for Human Exploration of the Moon

The Lunar Exploration Analysis Group (LEAG) was tasked by the Human Exploration Operations Mission Directorate (HEOMD) to establish a Specific Action Team (SAT) to review lunar Strategic Knowledge Gaps (SKGs) within the context of new lunar data and some specific human mission scenarios. Within this review, the SAT was to identify the SKGs that have been fully or partially retired, identify new SKGs resulting from new data and observations, and review quantitative descriptions of measurements that are required to fill knowledge gaps, the fidelity of the measurements needed, and if relevant, provide examples of existing instruments or potential missions capable of filling the SKGs.

Shearer, C. K.↗
NASA NTRS1997

The ASC Data Archive for the AXAF Ground Calibration

A data archive is near completion at the AXAF Science Center (ASC) to store and provide access to AXAF data. The archive is a distributed client/server system. It consists of a number of different servers which handle flat data files, relational data, replication across multiple sites, and the interface to the WWW. There is a 4GL client interface for each type of data server, C++ and Java APIs, and a number of standard clients to archive and retrieve data. The architecture is scalable and configurable in order to accommodate future data types and increasing data volumes. The first release of the system became available in August 1996 and has been successfully operated since then in support of the AXAF calibration at the George C. Marshall Space Flight Center, Huntsville, AL. This paper will present the overall archive architecture and the design of client and server components. It will also review the ground calibration data contents, the plan for flight data, and the access to the data by ASC internal users and processing pipelines.

Zografou, Panagoula↗
NASA NTRS1976

Contribution of the Spacelab data management system to lower cost space research

This paper reviews the design and operation of the Spacelab data management system as it has evolved. Significant improvements and extensions of the original baseline system have been incorporated and will be discussed. They include the capability for the remote control of Spacelab subsystems, improved remote data acquisition units, a high-rate digital data multiplexer, and an improved high-rate digital recorder. Emphasis will be placed on the overall system aspects, including considerations on the use of minicomputers as an adjunct to the basic Spacelab data system. The approach for experiment related software production and integration will be addressed as well. The paper focuses on the contributions of the data management system in reducing the cost of research in Spacelab.

Burger, J. J.↗
NASA NTRS1985

Space Shuttle interactive meteorological data system study

Although focused toward the operational meteorological support review and definition of an operational meteorological interactive data display systems (MIDDS) requirements for the Space Meteorology Support Group at NASA/Johnson Space Center, the total operational meteorological support requirements and a systems concept for the MIDDS network integration of NASA and Air Force elements to support the National Space Transportation System are also addressed.

Young, J. T.↗
NASA NTRS1985

Interactions between large space power systems and low-Earth-orbit plasmas

There is a growing tendency to plan space missions that will incorporate very large space power systems. These space power systems must function in the space plasma environment, which can impose operational limitations. As the power output increases, the operating voltage also must increase and this voltage, exposed at solar array interconnects, interacts with the local plasma. The implications of such interactions are considered. The available laboratory data for biased array segment tests are reviewed to demonstrate the basic interactions considered. A data set for a floating high voltage array test was used to generate approximate relationships for positive and negative current collection from plasmas. These relationships were applied to a hypothetical 100 kW power system operating in a 400 km, near equatorial orbit. It was found that discharges from the negative regions of the array are the most probable limiting factor in array operation.

Stevens, N. J.↗
NASA NTRS1994

Time and position accuracy using codeless GPS

The Global Positioning System has allowed scientists and engineers to make measurements having accuracy far beyond the original 15 meter goal of the system. Using global networks of P-Code capable receivers and extensive post-processing, geodesists have achieved baseline precision of a few parts per billion, and clock offsets have been measured at the nanosecond level over intercontinental distances. A cloud hangs over this picture, however. The Department of Defense plans to encrypt the P-Code (called Anti-Spoofing, or AS) in the fall of 1993. After this event, geodetic and time measurements will have to be made using codeless GPS receivers. However, there appears to be a silver lining to the cloud. In response to the anticipated encryption of the P-Code, the geodetic and GPS receiver community has developed some remarkably effective means of coping with AS without classified information. We will discuss various codeless techniques currently available and the data noise resulting from each. We will review some geodetic results obtained using only codeless data, and discuss the implications for time measurements. Finally, we will present the status of GPS research at JPL in relation to codeless clock measurements.

Dunn, C. E.↗
NASA NTRSDate not supplied

Analytical Framework for Rodent/NHP Data Set Utilization to Inform Human CNS Risk Estimation

Objectives Review and inform on tactics to analyze & communicate data from animal research (e.g., rodents, mini-pigs, NHPs, et al) exposed to single and combinations of spaceflight hazards, using NASA’s Human System Risk Board (HSRB) process for the Behavioral Medicine Risk - To quantitatively inform Behavioral Medicine Risk posture - i.e., likelihood (L) and consequence (C) - To help inform estimation of crew health standards for operational task performance (i.e., Fitness For Duty, Space Permissible Exposure Levels, Permissible Operational Limits).

Brain↗
NASA NTRS2023

Development of an Ultra High-Pressure Metals Promoted Combustion in Oxygen Test Apparatus

Materials flammability data is needed at pressures higher than ever tested before (greater than 10,000 psi). WSTF has designed and is currently building a metals flammability apparatus that can test metals up to 30,000 psi. Solid progress was achieved on the chamber in terms of system build up and fulfilling requirements to perform a NASA Test Readiness Review. Understanding metals flammability data at extreme pressure opens the doors for higher pressure and higher performance oxygen systems. Proposed systems include more reliable/higher performance propulsion systems and more reliable/lighter Environmental Control Life Support Systems (ECLSS). The test system needed for this testing required significant research and development to select a pressurization method and eliminate contact with potentially flammable materials back to the chamber. No additional promoted combustion data was collected in FY21. This International Research & Development (IRAD) proposal was critical to getting the system very close to operational status. This capability is critical to collect forward leaning material flammability data for future spacecraft and ground systems. Forward work has been identified and funding is being sought outside of the Center Innovation Fund (CIF) process for late FY23/FY24.

promoted combustion↗
NASA NTRS1973

Planetary program data systems standards

Stages in the development of planetary program data system standards since the inception of program standards in 1969 are identified as a review of the then existing data system element designs, the selection of canditate elements for additional standards, and the formation in 1972 of a Telecommunication Standards Committee for fulltime work in the final preparation of the standards. Further efforts in developing and implementing a complete set of standards within the possibly shortest time are planned.

Glahn, E. W.↗
NASA NTRS1977

Comments on the origins of the diffuse interstellar bands

Most work in recent years on the unidentified diffuse interstellar bands has been concentrated on the hypothesis that they are produced by some process in solid grains. We review that hypothesis and the arguments which support it, and find that diffuse band formation by certain classes of molecules should not yet be ruled out. Since several relevant observations have been made in the last four years, the observational data on the bands are reviewed. It would appear that these data are as consistent with molecular origins for the bands as with grain origins. Types of molecular transitions which give rise to 'diffuse' bands are described. These transitions can occur in relatively simple molecules composed of cosmically abundant elements and can produce broad, unresolvable profiles without destroying the molecule. New observations are suggested which could produce decisive evidence with which to determine whether the diffuse bands originate in grains, molecules, or both.

Smith, W. H.↗
NASA NTRS2020

UV/Vis+ Photochemistry Database: Structure, Content and Applications

The “science-softCon UV/Vis+ Photochemistry Database” (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV–Vis-NIR spectral data and other photochemical information assembled from published peer-reviewed papers. The database contains photochemical data including absorption, fluorescence, photoelectron, and circular and linear dichroism spectra, as well as quantum yields and photolysis related data that are critically needed in many scientific disciplines. This manuscript gives an outline regarding the structure and content of the “science-softCon UV/Vis+ Photochemistry Database”. The accurate and reliable molecular level information provided in this database is fundamental in nature and helps in proceeding further to understand photon, electron and ion induced chemistry of molecules of interest not only in spectroscopy, astrochemistry, astrophysics, Earth and planetary sciences, environmental chemistry, plasma physics, combustion chemistry but also in applied fields such as medical diagnostics, pharmaceutical sciences, biochemistry, agriculture, and catalysis. In order to illustrate this, we illustrate the use of the UV/Vis+ Photochemistry Database in four different fields of scientific endeavor.

Photochemistry↗
NASA NTRS2020

A Systematic Review of Local to Regional Yield Forecasting Approaches and Frequently Used Data Resources

Forecasting crop yields, or providing an expectation of ex-ante harvest amounts, is highly relevant to the whole agricultural production chain. Farmers can adapt their management, traders or insurers their pricing schemes, suppliers their stocks, logistic companies their routes, national authorities their food balance sheets to guide import or export and, finally, international aid organizations can mobilize reliefs. Evidence has grown in the literature that such forecasts with a meaningful lead time are possible on various geographic scales and for a broad range of crops. Here, we present a systematic review of the methods applied in end-of-season yield forecasting and three frequently used data sources: weather data, satellite data and crop masks. Our literature database comprises 362 studies (2004–2019) which were evaluated regarding methods, crops, regions, data sources, lead time and performance. Moreover, we present 24 sources of real-time and predictive weather data, 21 sources of remote sensing data and 16 crop masks. Yield forecasting in our literature sample has been performed for 44 crops in 71 countries, also including many non-staple crops, but with an apparent bias in regions and crops. Forecasting performance depends on various factors, including crop, region, method, lead time to harvest and input diversity. Our systematic review supports a broader application of locally successful approaches at larger scales by providing a comprehensive, accessible compendium of necessary information for yield forecasting. We discuss improvement potentials with respect to methodological approaches and available data sources. We additionally suggest standardization procedures for future forecasting studies and encourage studying additional crops and geographic regions. Implications of forecasts for different target groups on different scales and the adaptation towards climate change are also discussed.

Seasonal crop yield forecasting↗
NASA NTRS1992

Project Magnet High-level Vector Survey Data Reduction

Since 1951, the U.S. Navy, under its Project MAGNET program, has been continuously collecting vector aeromagnetic survey data to support the U.S. Defense Mapping Agency's world magnetic and charting program. During this forty-year period, a variety of survey platforms and instrumentation configurations have been used. The current Project MAGNET survey platform is a Navy Orion RP-3D aircraft which has been specially modified and specially equipped with a redundant suite of navigational positioning, attitude, and magnetic sensors. A review of the survey data collection procedures and calibration and editing techniques applied to the data generated by this suite of instrumentation will be presented. Among the topics covered will be the determination of its parameters from the low-level calibration maneuvers flown over geomagnetic observatories.

Rachel J Coleman↗
NASA NTRS2001

Fluctuating Pressure Data from 2-D Nozzle Cold Flow Tests (Dual Bell)

Rocket engines nozzle performance changes as a vehicle climbs through the atmosphere. An altitude compensating nozzle, ACN, is intended to improve on a fixed geometry bell nozzle that performs at optimum at only one trajectory point. In addition to nozzle performance, nozzle transient loads are an important consideration. Any nozzle experiences large transient toads when shocks pass through the nozzle at start and shutdown. Additional transient toads will occur at transitional flow conditions. The objectives of cold flow nozzle testing at MSFC are CFD benchmark / calibration and Unsteady flow / sideloads. Initial testing performed with 2-D inserts to 14" transonic wind tunnel. Recent review of 2-D data in preparation for nozzle test facility 3-D testing. This presentation shows fluctuating pressure data and some observations from 2-D dual-bell nozzle cold flow tests.

Nesman, Tomas E.↗
NASA NTRS1989

Time and frequency-domain identification and verification of BO-105 dynamic models

Mathematical models for the dynamics of the DLR BO 105 helicopter are extracted from flight test data using two different approaches: frequency-domain and time-domain identification. Both approaches are reviewed. Results from an extensive data consistency analysis are given. Identifications for 6 degrees of freedom (DOF) rigid body models are presented and compared in detail. The extracted models compare favorably and their prediction capability is demonstrated in verification results. Approaches to extend the 6 DOF models are addressed and first results are presented. System identification is broadly defined as the deduction of system characteristics from measured data. It provides the only possibility to extract both non-parametric (e.g., frequency responses) and parametric (e.g., state space matrices) aircraft models from flight test data and therefore gives a reliable characterization of the dynamics of the actually existing aircraft. Main applications of system identification are seen in areas where higher accuracies of the mathematical models are required: Simulation validation, control system design (in particular model-following control system design for in-flight simulation), and handling qualities.

Kaletka, Juergen↗
NASA NTRS1989

Time and frequency-domain identification and verification of BO-105 dynamic models

Mathematical models for the dynamics of the DLR BO 105 helicopter are extracted from flight test data using two different approaches: frequency-domain and time-domain identification. Both approaches are reviewed. Results from an extensive data consistency analysis are given. Identifications for 6 degrees of freedom (DOF) rigid body models are presented and compared in detail. The extracted models compare favorably and their prediction capability is demonstrated in verification results. Approaches to extend the 6 DOF models are addressed and first results are presented. System identification is broadly defined as the deduction of system characteristics from measured data. It provides the only possibility to extract both non-parametric (e.g., frequency responses) and parametric (e.g., state space matrices) aircraft models from flight test data and therefore gives a reliable characterization of the dynamics of the actually existing aircraft. Main applications of system identification are seen in areas where higher accuracies of the mathematical models are required: Simulation validation, control system design (in particular model-following control system design for in-flight simulation), and handling qualities.

Kaletka, Juergen↗
NASA NTRS2010

The New Face of Data Accessibility

Management of medical and research data at NASA's Johnson Space Center has been addressed with two separate, independent systems: the Lifetime Surveillance of Astronaut Health (formerly, The Longitudinal Study of Astronaut Health) (LSAH) and the Life Sciences Data Archive (LSDA). Project management for these has been autonomous with little or no cross-over of goals, objectives or strategy. The result has been limited debate and discussion regarding how contents from one repository might impact or guide the direction of the other. It is decidedly more efficient to use existing data and information than to re-generate them. Ensuring that both clinical and research data / information are accessible for review is a central concept to the decision to unify these repositories. In the past, research data from flight and ground analogs has been held in the LSDA and medical data held in the Electronic Medical Record or in console flight surgeon logs and records. There was little cross-pollination between medical and research findings and, as a result, applicable research was not being fully incorporated into clinical, in-flight practice. Conversely, findings by the console surgeon were not being picked up by the research community. The desired life cycle for risk mitigation was not being fully realized. The goal of unifying these repositories and processes is to provide a closely knit approach to handling medical and research data, which will not only engender discussion and debate but will also ensure that both categories of data and information are used to enhance the use of medical and research data to reduce risk and promote the understanding of space physiology, countermeasures and other mitigation strategies

Fitts, Mary A.↗