Advanced Manned Launch System (AMLS) study

NASA Technical Reports Server (NTRS)

Ehrlich, Carl F., Jr.; Potts, Jack; Brown, Jerry; Schell, Ken; Manley, Mary; Chen, Irving; Earhart, Richard; Urrutia, Chuck; Randolph, Ray; Morris, Jim

1992-01-01

To assure national leadership in space operations and exploration in the future, NASA must be able to provide cost effective and operationally efficient space transportation. Several NASA studies and the joint NASA/DoD Space Transportation Architecture Studies (STAS) have shown the need for a multi-vehicle space transportation system with designs driven by enhanced operations and low costs. NASA is currently studying an advanced manned launch system (AMLS) approach to transport crew and cargo to the Space Station Freedom. Several single and multiple stage systems from air-breathing to all-rocket concepts are being examined in a series of studies potential replacements for the Space Shuttle launch system in the 2000-2010 time frame. Rockwell International Corporation, under contract to the NASA Langley Research Center, has analyzed a two-stage all-rocket concept to determine whether this class of vehicles is appropriate for the AMLS function. The results of the pre-phase A study are discussed.

Exploration of transit's sustainability competitiveness : summary.

DOT National Transportation Integrated Search

2011-01-01

Public transportation is an important community amenity, offering economy of energy use and space. A common assumption is that public transportation is always more energy efficient than the private automobile. University of South Florida researchers ...

Conestoga 2: A low cost commercial space transport system

NASA Technical Reports Server (NTRS)

Rasmussen, R. O.

1984-01-01

Conestoga 2 is currently under development. It is capable of inserting 500 Kg satellites into 800 Km circular polar orbits. Conestoga 2 makes maximum use of existing (developed) technology and hardware. Its commercial objective is to fill a need for low cost low Earth orbital transport not efficiently served by Shuttle or larger space transport systems. Low Earth orbit markets, foreign participation, and launch site considerations are discussed along with technical and economic trade-offs.

Efficiency of Energy Use in the United States

ERIC Educational Resources Information Center

Hirst, Eric; Moyers, John C.

1973-01-01

Describes ways to reduce energy consumption in transportation, space heating, and air conditioning. Greater efficiency for energy use from an engineering point of view is possible in present circumstances. (PS)

75 FR 77955 - Intelligent Transportation Systems Program Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-14

... under Section 5305 of Public Law 109-59, Safe, Accountable, Flexible, Efficient Transportation Equity... Discussion (Continued); and (3) Summary and Wrap Up. The meeting will be open to the public, but space will...

77 FR 26067 - Intelligent Transportation Systems Program Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-02

... under Section 5305 of Public Law 109-59, Safe, Accountable, Flexible, Efficient Transportation Equity...) Timeline for future committee work. The meeting will be open to the public, but limited space will be...

Mars Missions Using Emerging Commercial Space Transportation Capabilities

NASA Technical Reports Server (NTRS)

Gonzales, Andrew A.

2016-01-01

New Discoveries regarding the Martian Environment may impact Mars mission planning. Transportation of investigation payloads can be facilitated by Commercial Space Transportation options. The development of Commercial Space Transportation. Capabilities anticipated from various commercial entities are examined objectively. The potential for one of these options, in the form of a Mars Sample Return mission, described in the results of previous work, is presented to demonstrate a high capability potential. The transportation needs of the Mars Environment Team Project at ISU 2016 may fit within the payload capabilities of a Mars Sample Return mission, but the payload elements may or may not differ. Resource Modules will help you develop a component of a strategy to address the Implications of New Discoveries in the Martian Environment using the possibility of efficient, commercial space transportation options. Opportunities for open discussions as appropriate during the team project formulation period at the end of each Resource Module. The objective is to provide information that can be incorporated into your work in the Team Project including brainstorming.

Ventilation Transport Trade Study for Future Space Suit Life Support Systems

NASA Technical Reports Server (NTRS)

Kempf, Robert; Vogel, Matthew; Paul, Heather L.

2008-01-01

A new and advanced portable life support system (PLSS) for space suit surface exploration will require a durable, compact, and energy efficient system to transport the ventilation stream through the space suit. Current space suits used by NASA circulate the ventilation stream via a ball-bearing supported centrifugal fan. As NASA enters the design phase for the next generation PLSS, it is necessary to evaluate available technologies to determine what improvements can be made in mass, volume, power, and reliability for a ventilation transport system. Several air movement devices already designed for commercial, military, and space applications are optimized in these areas and could be adapted for EVA use. This paper summarizes the efforts to identify and compare the latest fan and bearing technologies to determine candidates for the next generation PLSS.

77 FR 57640 - Intelligent Transportation Systems Program Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-18

... 5305 of Public Law 109-59, Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy... and Wrap-up. The meeting will be open to the public, but limited space will be available on a first...

78 FR 16030 - Intelligent Transportation Systems Program Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-13

... Section 5305 of Public Law 109-59, Safe, Accountable, Flexible, Efficient Transportation Equity Act: A.... The meeting will be open to the public, but limited space will be available on a first-come, first...

Building Operations Efficiencies into NASA's Ares I Crew Launch Vehicle Design

NASA Technical Reports Server (NTRS)

Dumbacher, Daniel

2006-01-01

The U.S. Vision for Space Exploration guides the National Aeronautics and Space Administration s (NASA's) challenging missions that expand humanity s boundaries and open new routes to the space frontier. With the Agency's commitment to complete the International Space Station (ISS) and to retire the venerable Space Shuttle by 2010, the NASA Administrator commissioned the Exploration Systems Architecture Study (ESAS) in mid 2005 to analyze options for safe, simple, cost-efficient launch solutions that could deliver human-rated space transportation capabilities in a timely manner within fixed budget guidelines. The Exploration Launch Projects Office, chartered in October 2005, has been conducting systems engineering studies and business planning over the past few months to successively refine the design configurations and better align vehicle concepts with customer and stakeholder requirements, such as significantly reduced life-cycle costs. As the Agency begins the process of replacing the Shuttle with a new generation of spacecraft destined for missions beyond low-Earth orbit to the Moon and Mars, NASA is designing the follow-on crew and cargo launch systems for maximum operational efficiencies. To sustain the long-term exploration of space, it is imperative to reduce the $4.5 billion NASA typically spends on space transportation each year. This paper gives top-level information about how the follow-on Ares I Crew Launch Vehicle (CLV) is being designed for improved safety and reliability, coupled with reduced operations costs.

76 FR 6841 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-08

... Section 5305 of Public Law 109-59, Safe, Accountable, Flexible, Efficient Transportation Equity Act: A... open to the public, but space will be available on a first-come, first-served basis. Members of the...

The Application of Neutron Transport Green's Functions to Threat Scenario Simulation

NASA Astrophysics Data System (ADS)

Thoreson, Gregory G.; Schneider, Erich A.; Armstrong, Hirotatsu; van der Hoeven, Christopher A.

2015-02-01

Radiation detectors provide deterrence and defense against nuclear smuggling attempts by scanning vehicles, ships, and pedestrians for radioactive material. Understanding detector performance is crucial to developing novel technologies, architectures, and alarm algorithms. Detection can be modeled through radiation transport simulations; however, modeling a spanning set of threat scenarios over the full transport phase-space is computationally challenging. Previous research has demonstrated Green's functions can simulate photon detector signals by decomposing the scenario space into independently simulated submodels. This paper presents decomposition methods for neutron and time-dependent transport. As a result, neutron detector signals produced from full forward transport simulations can be efficiently reconstructed by sequential application of submodel response functions.

Galactic Cosmic-ray Transport in the Global Heliosphere: A Four-Dimensional Stochastic Model

NASA Astrophysics Data System (ADS)

Florinski, V.

2009-04-01

We study galactic cosmic-ray transport in the outer heliosphere and heliosheath using a newly developed transport model based on stochastic integration of the phase-space trajectories of Parker's equation. The model employs backward integration of the diffusion-convection transport equation using Ito calculus and is four-dimensional in space+momentum. We apply the model to the problem of galactic proton transport in the heliosphere during a negative solar minimum. Model results are compared with the Voyager measurements of galactic proton radial gradients and spectra in the heliosheath. We show that the heliosheath is not as efficient in diverting cosmic rays during solar minima as predicted by earlier two-dimensional models.

14 CFR 77.5 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Applicability. 77.5 Section 77.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SAFE... of the proposed construction or alteration on safety in air commerce and the efficient use and...

14 CFR 77.5 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Applicability. 77.5 Section 77.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SAFE... of the proposed construction or alteration on safety in air commerce and the efficient use and...

14 CFR 77.5 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Applicability. 77.5 Section 77.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SAFE... of the proposed construction or alteration on safety in air commerce and the efficient use and...

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE PAGES

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.; ...

2018-01-12

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Management and analysis of Michigan intelligent transportation systems center data with application to the Detroit area I-75 corridor.

DOT National Transportation Integrated Search

2011-02-01

An understanding of traffic flow in time and space is fundamental to the development of : strategies for the efficient use of the existing transportation infrastructure in large : metropolitan areas. Thus, this project involved developing the methods...

14 CFR 77.1 - Scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Scope. 77.1 Section 77.1 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE OBJECTS... navigation, to determine their effect on the safe and efficient use of airspace; (d) Provides for public...

14 CFR 77.1 - Scope.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Scope. 77.1 Section 77.1 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE OBJECTS... obstructions to air navigation, to determine their effect on the safe and efficient use of airspace; (d...

MESTRN: A Deterministic Meson-Muon Transport Code for Space Radiation

NASA Technical Reports Server (NTRS)

Blattnig, Steve R.; Norbury, John W.; Norman, Ryan B.; Wilson, John W.; Singleterry, Robert C., Jr.; Tripathi, Ram K.

2004-01-01

A safe and efficient exploration of space requires an understanding of space radiations, so that human life and sensitive equipment can be protected. On the way to these sensitive sites, the radiation fields are modified in both quality and quantity. Many of these modifications are thought to be due to the production of pions and muons in the interactions between the radiation and intervening matter. A method used to predict the effects of the presence of these particles on the transport of radiation through materials is developed. This method was then used to develop software, which was used to calculate the fluxes of pions and muons after the transport of a cosmic ray spectrum through aluminum and water. Software descriptions are given in the appendices.

Advanced transportation concept for round-trip space travel

NASA Technical Reports Server (NTRS)

Yen, Chen-Wan L.

1988-01-01

A departure from the conventional concept of round-trip space travel is introduced. It is shown that a substantial reduction in the initial load required of the Shuttle or other launch vehicle can be achieved by staging the ascent orbit and leaving fuel for the return trip at each stage of the orbit. Examples of round trips from a low-inclination LEO to a high-inclination LEO and from an LEO to a GEO are used to show the merits of the new concept. Potential problem areas and research needed for the development of an efficient space transportation network are discussed.

Logistics support economy and efficiency through consolidation and automation

NASA Technical Reports Server (NTRS)

Savage, G. R.; Fontana, C. J.; Custer, J. D.

1985-01-01

An integrated logistics support system, which would provide routine access to space and be cost-competitive as an operational space transportation system, was planned and implemented to support the NSTS program launch-on-time goal of 95 percent. A decision was made to centralize the Shuttle logistics functions in a modern facility that would provide office and training space and an efficient warehouse area. In this warehouse, the emphasis is on automation of the storage and retrieval function, while utilizing state-of-the-art warehousing and inventory management technology. This consolidation, together with the automation capabilities being provided, will allow for more effective utilization of personnel and improved responsiveness. In addition, this facility will be the prime support for the fully integrated logistics support of the operations era NSTS and reduce the program's management, procurement, transportation, and supply costs in the operations era.

Effects of Transport at Weaning on the Behavior, Physiology and Performance of Pigs

PubMed Central

Sutherland, Mhairi A.; Backus, Brittany L.; McGlone, John J.

2014-01-01

Simple Summary Pigs are commonly transported to separate production facilities at weaning to reduce disease transfer, enhance productivity and to improve overall operational efficiency. A review of the scientific literature suggests that these animals experience stress due to concurrent weaning and transport; however, gaps in the knowledge include the short and long term health and welfare implications of transporting pigs at weaning. Pig welfare and the efficiency of the swine industry may improve if science-based recommendations were in place. Abstract Transport of pigs to separate production facilities at the time of weaning is a common practice, primarily performed to reduce vertical transfer of disease and enhance production and overall farm efficiency. During transport, pigs are exposed to numerous stressors in conjunction with the stress experienced as a result of weaning. In this review, the behavioral and physiological response of pigs experiencing weaning and transport simultaneously will be described, including the effects of space allowance, season and transport duration. Based on the scientific literature, the gaps in the knowledge regarding potential welfare issues are discussed. Changes in behavior and physiology suggest that weaned pigs may experience stress due to transport. Space allowance, season and duration are aspects of transport that can have a marked impact on these responses. To date, the literature regarding the effects of transport on weaned pigs has primarily focused on the short term stress response and little is known about the effects of concurrent weaning and transport on other aspects of pig welfare including morbidity and mortality rates. Greater understanding of the short and long term consequences of transport on weaned pig welfare particularly in relation to factors such as trip duration, provision of feed and water, and best handling practices would benefit the swine industry. Furthermore, the development of guidelines and recommendations to enhance the short and long term welfare of weaned pigs in relation to transport are needed. PMID:26479005

Geostationary platform study: Advanced ESGP/evolutionary SSF accommodation study

NASA Technical Reports Server (NTRS)

1990-01-01

The implications on the evolutionary space station of accommodating geosynchronous Earth Orbit (GEO) facilities including unmanned satellites and platforms, manned elements, and transportation and servicing vehicles/elements. The latest existing definitions of typical unmanned GEO facilities and transportation and servicing vehicles/elements are utilized. The physical design, functional design, and operations implications at the space station are determined. Various concepts of the space station from past studies are utilized ranging from the IOC Multifunction Space Station to a branched transportation node space station, and the implications of the accommodation the GEO infrastructure of each type are assessed. Where possible, parametric data are provided to show the implications of variations in sizes and quantities of elements, launch rates, crew sizes, etc. The use of advanced automation, robotics equipment, and an efficient mix of manned/automated support for accomplishing necessary activities at the space station are identified and assessed. The products of this study are configuration sketches, resource requirements, trade studies, and parametric data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolterfoht, Martin; Armin, Ardalan; Pandey, Ajay K.

Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC{sub 71}BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersivemore » transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.« less

The Ninth National Space Symposium

NASA Astrophysics Data System (ADS)

Lipskin, Beth Ann; Patterson, Sara; Brescia, David A.; Burk, Donna; Flannery, Jack; St. John, Pat; Zimkas, Chuck

Proceedings of the Ninth National Space Symposium held 13-16 April 1993 by the United States Space Foundation are presented. Presentations made at the symposium are included. Topics discussed include: Change, Challenge and Opportunity; Washington Insiders: National Space Policy and Budget Issues; Civil Space: a Vision for the Future; Space Power for an Expanded Vision; Unparalled Launch Vehicle Propulsion Capabilities; National Security Space Issues; Perspectives on the Air Force in Space; Future Technology: Space Propulsion, Earth Observation and International Cooperation; Achieving Efficient Space Transportation; the Future in Space Exploration; Kids, Parents and Teachers are into Space; and Public Congressional Forum on Space - International Space Issues.

Radiated microwave power transmission system efficiency measurements

NASA Technical Reports Server (NTRS)

Dickinson, R. M.; Brown, W. C.

1975-01-01

The measured and calculated results from determining the operating efficiencies of a laboratory version of a system for transporting electric power from one point to another via a wireless free space radiated microwave beam are reported. The system's overall end-to-end efficiency as well as intermediated conversion efficiencies were measured. The maximum achieved end-to-end dc-to-ac system efficiency was 54.18% with a probable error of + or - 0.94%. The dc-to-RF conversion efficiency was measured to be 68.87% + or - 1.0% and the RF-to-dc conversion efficiency was 78.67 + or - 1.1%. Under these conditions a dc power of 495.62 + or - 3.57 W was received with a free space transmitter antenna receiver antenna separation of 170.2 cm (67 in).

Faster Heavy Ion Transport for HZETRN

NASA Technical Reports Server (NTRS)

Slaba, Tony C.

2013-01-01

The deterministic particle transport code HZETRN was developed to enable fast and accurate space radiation transport through materials. As more complex transport solutions are implemented for neutrons, light ions (Z < 2), mesons, and leptons, it is important to maintain overall computational efficiency. In this work, the heavy ion (Z > 2) transport algorithm in HZETRN is reviewed, and a simple modification is shown to provide an approximate 5x decrease in execution time for galactic cosmic ray transport. Convergence tests and other comparisons are carried out to verify that numerical accuracy is maintained in the new algorithm.

Pricing of NASA Space Shuttle transportation system cargo

NASA Technical Reports Server (NTRS)

Hale, C. W.

1979-01-01

A two-part pricing policy is investigated as the most feasible method of pricing the transportation services to be provided by NASA's SSTS. Engineering cost estimates and a deterministic operating cost model generate a data base and develop a procedure for pricing the services of the SSTS. It is expected that the SSTS will have a monopoly on space material processing in areas of crystal growth, glass processing, metallurgical space applications, and biomedical processes using electrophoresis which will require efficient pricing. Pricing problems, the SSTS operating costs based on orbit elevation, number of launch sites, and number of flights, capital costs of the SSTS, research and development costs, allocation of joint transportation costs of the SSTS to a particular space processing activity, and rates for the SSTS are discussed. It is concluded that joint costs for commercial cargoes carried in the SSTS can be most usefully handled by making cost allocations based on proportionate capacity utilization.

Computer Applications in Class and Transportation Scheduling. Educational Management Review Series Number 1.

ERIC Educational Resources Information Center

Piele, Philip K.

This document shows how computer technology can aid educators in meeting demands for improved class scheduling and more efficient use of transportation resources. The first section surveys literature on operational systems that provide individualized scheduling for students, varied class structures, and maximum use of space and staff skills.…

A POD reduced order model for resolving angular direction in neutron/photon transport problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchan, A.G., E-mail: andrew.buchan@imperial.ac.uk; Calloo, A.A.; Goffin, M.G.

2015-09-01

This article presents the first Reduced Order Model (ROM) that efficiently resolves the angular dimension of the time independent, mono-energetic Boltzmann Transport Equation (BTE). It is based on Proper Orthogonal Decomposition (POD) and uses the method of snapshots to form optimal basis functions for resolving the direction of particle travel in neutron/photon transport problems. A unique element of this work is that the snapshots are formed from the vector of angular coefficients relating to a high resolution expansion of the BTE's angular dimension. In addition, the individual snapshots are not recorded through time, as in standard POD, but instead theymore » are recorded through space. In essence this work swaps the roles of the dimensions space and time in standard POD methods, with angle and space respectively. It is shown here how the POD model can be formed from the POD basis functions in a highly efficient manner. The model is then applied to two radiation problems; one involving the transport of radiation through a shield and the other through an infinite array of pins. Both problems are selected for their complex angular flux solutions in order to provide an appropriate demonstration of the model's capabilities. It is shown that the POD model can resolve these fluxes efficiently and accurately. In comparison to high resolution models this POD model can reduce the size of a problem by up to two orders of magnitude without compromising accuracy. Solving times are also reduced by similar factors.« less

The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution

NASA Astrophysics Data System (ADS)

Shobe, Charles M.; Tucker, Gregory E.; Barnhart, Katherine R.

2017-12-01

Models of landscape evolution by river erosion are often either transport-limited (sediment is always available but may or may not be transportable) or detachment-limited (sediment must be detached from the bed but is then always transportable). While several models incorporate elements of, or transition between, transport-limited and detachment-limited behavior, most require that either sediment or bedrock, but not both, are eroded at any given time. Modeling landscape evolution over large spatial and temporal scales requires a model that can (1) transition freely between transport-limited and detachment-limited behavior, (2) simultaneously treat sediment transport and bedrock erosion, and (3) run in 2-D over large grids and be coupled with other surface process models. We present SPACE (stream power with alluvium conservation and entrainment) 1.0, a new model for simultaneous evolution of an alluvium layer and a bedrock bed based on conservation of sediment mass both on the bed and in the water column. The model treats sediment transport and bedrock erosion simultaneously, embracing the reality that many rivers (even those commonly defined as bedrock rivers) flow over a partially alluviated bed. SPACE improves on previous models of bedrock-alluvial rivers by explicitly calculating sediment erosion and deposition rather than relying on a flux-divergence (Exner) approach. The SPACE model is a component of the Landlab modeling toolkit, a Python-language library used to create models of Earth surface processes. Landlab allows efficient coupling between the SPACE model and components simulating basin hydrology, hillslope evolution, weathering, lithospheric flexure, and other surface processes. Here, we first derive the governing equations of the SPACE model from existing sediment transport and bedrock erosion formulations and explore the behavior of local analytical solutions for sediment flux and alluvium thickness. We derive steady-state analytical solutions for channel slope, alluvium thickness, and sediment flux, and show that SPACE matches predicted behavior in detachment-limited, transport-limited, and mixed conditions. We provide an example of landscape evolution modeling in which SPACE is coupled with hillslope diffusion, and demonstrate that SPACE provides an effective framework for simultaneously modeling 2-D sediment transport and bedrock erosion.

Approach to an Affordable and Productive Space Transportation System

NASA Technical Reports Server (NTRS)

McCleskey, Carey M.; Rhodes, Russel E.; Lepsch, Roger A.; Henderson, Edward M.; Robinson, John W.

2012-01-01

This paper describes an approach for creating space transportation architectures that are affordable, productive, and sustainable. The architectural scope includes both flight and ground system elements, and focuses on their compatibility to achieve a technical solution that is operationally productive, and also affordable throughout its life cycle. Previous papers by the authors and other members of the Space Propulsion Synergy Team (SPST) focused on space flight system engineering methods, along with operationally efficient propulsion system concepts and technologies. This paper follows up previous work by using a structured process to derive examples of conceptual architectures that integrate a number of advanced concepts and technologies. The examples are not intended to provide a near-term alternative architecture to displace current near-term design and development activity. Rather, the examples demonstrate an approach that promotes early investments in advanced system concept studies and trades (flight and ground), as well as in advanced technologies with the goal of enabling highly affordable, productive flight and ground space transportation systems.

Design and Commissioning of a Transportable Laser Ranging Station STAR-C

NASA Astrophysics Data System (ADS)

Humbert, L.; Hasenohr, T.; Hampf, D.; Riede, W.

An increasing number of space debris and the rise of mega constellations as well as the deployment of small cost efficient satellites are a growing concern for space faring nations and their missions. Hence, a tight network of worldwide stations to support maintenance of catalogues for various tasks such as space surveillance tracking and space traffic management will significantly increase the reliability and availability of the collected data and therefore the safety of missions. A promising concept are transportable laser ranging stations in order to increase the number of observing stations and hence the coverage of the sky. Built and tested on a building test site they can be deployed to a desired site for operation. High energy laser with short pulses provide accurate ranging data to objects in space both cooperative and uncooperative, e.g. objects with a retroreflector and without one. This work introduces the progress of a transportable laser ranging station, of a Surveillance, Tracking and Ranging Container (STAR-C), built into a 20ft ISO container.

Effect of the geometry of the anodized titania nanotube array on the performance of dye-sensitized solar cells.

PubMed

Sun, Lidong; Zhang, Sam; Sun, Xiaowei; He, Xiaodong

2010-07-01

Highly ordered TiO2 nanotube arrays are superior photoanodes for dye-sensitized solar cells (DSSCs) due to reduced intertube connections, vectorial electron transport, suppressed electron recombination, and enhanced light scattering. Performance of the cells is greatly affected by tube geometry, such as wall thickness, length, inner diameter and intertube spacing. In this paper, effect of geometry on the photovoltaic characteristics of DSSCs is reviewed. The nanotube wall has to be thick enough for a space charge layer to form for faster electron transportation and reduced recombination. When the tube wall is too thin to support the space charge layer, electron transport in the nanotubes will be hindered and reduced to that similar in a typical nanoparticle photoanode, and recombination will easily take place. Length of the nanotubes also plays a role: longer tube length is desired because of more dye loading, however, tube length longer than the electron diffusion length results in low collecting efficiency, which in turn, results in low short-circuit current density and thus low overall conversion efficiency. The tube inner diameter (pore size) affects the conversion efficiency through effective surface area, i.e., larger pore size gives rise to smaller surface area for dye adsorption, which results in low short-circuit current density under the same light soaking. Another issue that may seriously affect the conversion efficiency is whether each of the tube stands alone (free from connecting to the neighboring tubes) to facilitate infiltration of dye and fully use the outer surface area.

Building Operations Efficiencies into NASA's Ares I Crew Launch Vehicle Design

NASA Technical Reports Server (NTRS)

Dumbacher, Daniel L.; Davis, Stephan R.

2007-01-01

The U.S. Vision for Space Exploration guides the National Aeronautics and Space Administration's (NASA's) challenging missions that expand humanity's boundaries and open new routes to the space frontier. With the Agency's commitment to complete the International Space Station (ISS) and to retire the venerable Space Shuttle by 2010, the NASA Administrator commissioned the Exploration Systems Architecture Study (ESAS) in 2005 to analyze options for safe, simple, cost-efficient launch solutions that could deliver human-rated space transportation capabilities in a timely manner within fixed budget guidelines. The Exploration Launch Projects (ELP) Office, chartered by the Constellation Program in October 2005, has been conducting systems engineering studies and business planning to successively refine the design configurations and better align vehicle concepts with customer and stakeholder requirements, such as significantly reduced life-cycle costs. As the Agency begins the process of replacing the Shuttle with a new generation of spacecraft destined for missions beyond low-Earth orbit to the Moon and Mars, NASA is designing the follow-on crew and cargo launch systems for maximum operational efficiencies. To sustain the long-term exploration of space, it is imperative to reduce the $4 billion NASA typically spends on space transportation each year. This paper gives toplevel information about how the follow-on Ares I Crew Launch Vehicle (CLV) is being designed for improved safety and reliability, coupled with reduced operations costs. These methods include carefully developing operational requirements; conducting operability design and analysis; using the latest information technology tools to design and simulate the vehicle; and developing a learning culture across the workforce to ensure a smooth transition between Space Shuttle operations and Ares vehicle development.

A new era of space transportation. [Space Shuttle system utilization

NASA Technical Reports Server (NTRS)

Fletcher, J. C.

1976-01-01

It is pointed out that founded on the experiences of Apollo, Skylab, and the Apollo/Soyuz mission an era is entered which will be characterized by a displacement of the interface between the experimenter and his experiment from the control center on the ground to the laboratory in orbit. A new world has been opened by going into space. Economic applications are related to the achievement of an enormous efficiency in world communications at a much lower cost. However, programs of space exploration and usage are under severe economic constraints. A primary tool to lower the cost of programs is to be the Space Transportation System using the Space Shuttle. It is emphasized that the Shuttle system is an international enterprise. Attention is also given to the results of the Viking missions, the Landsat satellites, and applications of space technology for science and commerce.

Space Transportation System (STS) propellant scavenging system study. Volume 1: Technical report

NASA Technical Reports Server (NTRS)

1985-01-01

The objectives are to define the most efficient and cost effective methods for scavenging cryogenic and storable propellants and then define the requirements for these scavenging systems. For cryogenic propellants, scavenging is the transfer of propellants from the Shuttle orbiter external tank (ET) and/or main propulsion subsystems (MPS) propellant lines into storage tanks located in the orbiter payload bay for delivery to the user station by a space based transfer stage or the Space Transportation System (STS) by direct insertion. For storable propellants, scavenging is the direct transfer from the orbital maneuvering subsystem (OMS) and/or tankage in the payload bay to users in LEO as well as users in the vicinity of the Space Station.

49 CFR 176.405 - Stowage of charcoal.

Code of Federal Regulations, 2013 CFR

2013-10-01

... bags and offered for transportation on board a vessel in a quantity over 1016 kg (2240 pounds) must be loaded so that the bags are laid horizontally and stacked with space for efficient air circulation. If... repaired bags restowed. (d) Charcoal “screenings” packed in bags must be stowed to provide spaces for air...

49 CFR 176.405 - Stowage of charcoal.

Code of Federal Regulations, 2014 CFR

2014-10-01

... bags and offered for transportation on board a vessel in a quantity over 1016 kg (2240 pounds) must be loaded so that the bags are laid horizontally and stacked with space for efficient air circulation. If... repaired bags restowed. (d) Charcoal “screenings” packed in bags must be stowed to provide spaces for air...

49 CFR 176.405 - Stowage of charcoal.

Code of Federal Regulations, 2012 CFR

2012-10-01

... bags and offered for transportation on board a vessel in a quantity over 1016 kg (2240 pounds) must be loaded so that the bags are laid horizontally and stacked with space for efficient air circulation. If... repaired bags restowed. (d) Charcoal “screenings” packed in bags must be stowed to provide spaces for air...

The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires

NASA Astrophysics Data System (ADS)

Hoffmann, Eric A.

State of the art semiconductor materials engineering provides the possibility to fabricate devices on the lower end of the mesoscopic scale and confine only a handful of electrons to a region of space. When the thermal energy is reduced below the energetic quantum level spacing, the confined electrons assume energy levels akin to the core-shell structure of natural atoms. Such "artificial atoms", also known as quantum dots, can be loaded with electrons, one-by-one, and subsequently unloaded using source and drain electrical contacts. As such, quantum dots are uniquely tunable platforms for performing quantum transport and quantum control experiments. Voltage-biased electron transport through quantum dots has been studied extensively. Far less attention has been given to thermoelectric effects in quantum dots, that is, electron transport induced by a temperature gradient. This dissertation focuses on the efficiency of direct thermal-to-electric energy conversion in InAs/InP quantum dots embedded in nanowires. The efficiency of thermoelectric heat engines is bounded by the same maximum efficiency as cyclic heat engines; namely, by Carnot efficiency. The efficiency of bulk thermoelectric materials suffers from their inability to transport charge carriers selectively based on energy. Owing to their three-dimensional momentum quantization, quantum dots operate as electron energy filters---a property which can be harnessed to minimize entropy production and therefore maximize efficiency. This research was motivated by the possibility to realize experimentally a thermodynamic heat engine operating with near-Carnot efficiency using the unique behavior of quantum dots. To this end, a microscopic heating scheme for the application of a temperature difference across a quantum dot was developed in conjunction with a novel quantum-dot thermometry technique used for quantifying the magnitude of the applied temperature difference. While pursuing high-efficiency thermoelectric performance, many mesoscopic thermoelectric effects were observed and studied, including Coulomb-blockade thermovoltage oscillations, thermoelectric power generation, and strong nonlinear behavior. In the end, a quantum-dot-based thermoelectric heat engine was achieved and demonstrated an electronic efficiency of up to 95% Carnot efficiency.

NASA's Ares I and Ares V Launch Vehicles -- Effective Space Operations Through Efficient Ground Operations

NASA Technical Reports Server (NTRS)

Dumbacher, Daniel L.; Singer, Christopher E.; Onken, Jay F.

2008-01-01

The United States (U.S.) plans to return to the Moon by 2020, with the development of a new human-rated space transportation system to replace the Space Shuttle, which is due for retirement in 2010 after it completes its missions of building the International Space Station and servicing the Hubble Space Telescope. Powering the future of space-based scientific exploration will be the Ares I Crew Launch Vehicle, which will transport the Orion Crew Exploration Vehicle to orbit where it will rendezvous with the Lunar Lander. which will be delivered by the Ares V Cargo Launch Vehicle. This new transportation infrastructure, developed by the National Aeronautics and Space Administration (NASA), will allow astronauts to leave low-Earth orbit for extended lunar exploration and preparation for the first footprint on Mars. All space-based operations begin and are controlled from Earth. NASA's philosophy is to deliver safe, reliable, and cost-effective solutions to sustain a multi-billion-dollar program across several decades. Leveraging 50 years of lessons learned, NASA is partnering with private industry, while building on proven hardware experience. This paper will discuss how the Engineering Directorate at NASA's Marshall Space Flight Center is working with the Ares Projects Office to streamline ground operations concepts and reduce costs. Currently, NASA's budget is around $17 billion, which is less than 1 percent of the U.S. Federal budget. Of this amount, NASA invests approximately $4.5 billion each year in Space Shuttle operations, regardless of whether the spacecraft is flying or not. The affordability requirement is for the Ares I to reduce this expense by 50 percent, in order to allow NASA to invest more in space-based scientific operations. Focusing on this metric, the Engineering Directorate provides several solutions-oriented approaches, including Lean/Six Sigma practices and streamlined hardware testing and integration, such as assembling major hardware elements before shipping to the Kennedy Space Center for launch operations. This paper provides top-level details for several cost saving initiatives, including both process and product improvements that will result in space transportation systems that are designed with operations efficiencies in mind. The Engineering Directorate provides both the intellectual capital embodied in an experienced workforce and unique facilities in which to validate the information technology tools that allow a nationwide team to collaboratively connect across miles that separate them and the engineering disciplines that integrate various piece parts into a whole system. As NASA transforms ground-based operations, it also is transitioning its workforce from an era of intense hands-on labor to a new one of mechanized conveniences and robust hardware with simpler interfaces. Ensuring that space exploration is on sound footing requires that operations efficiencies be designed into the transportation system and implemented in the development stage. Applying experience gained through decades of ground and space op'erations, while using value-added processes and modern business and engineering tools, is the philosophy upon which a new era of exploration will be built to solve some of the most pressing exploration challenges today -- namely, safety, reliability, and affordability.

Real-space observation of unbalanced charge distribution inside a perovskite-sensitized solar cell.

PubMed

Bergmann, Victor W; Weber, Stefan A L; Javier Ramos, F; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Li, Dan; Domanski, Anna L; Lieberwirth, Ingo; Ahmad, Shahzada; Berger, Rüdiger

2014-09-22

Perovskite-sensitized solar cells have reached power conversion efficiencies comparable to commercially available solar cells used for example in solar farms. In contrast to silicon solar cells, perovskite-sensitized solar cells can be made by solution processes from inexpensive materials. The power conversion efficiency of these cells depends substantially on the charge transfer at interfaces. Here we use Kelvin probe force microscopy to study the real-space cross-sectional distribution of the internal potential within high efficiency mesoscopic methylammonium lead tri-iodide solar cells. We show that the electric field is homogeneous through these devices, similar to that of a p-i-n type junction. On illumination under short-circuit conditions, holes accumulate in front of the hole-transport layer as a consequence of unbalanced charge transport in the device. After light illumination, we find that trapped charges remain inside the active device layers. Removing these traps and the unbalanced charge injection could enable further improvements in performance of perovskite-sensitized solar cells.

One-dimensional transport equation models for sound energy propagation in long spaces: theory.

PubMed

Jing, Yun; Larsen, Edward W; Xiang, Ning

2010-04-01

In this paper, a three-dimensional transport equation model is developed to describe the sound energy propagation in a long space. Then this model is reduced to a one-dimensional model by approximating the solution using the method of weighted residuals. The one-dimensional transport equation model directly describes the sound energy propagation in the "long" dimension and deals with the sound energy in the "short" dimensions by prescribed functions. Also, the one-dimensional model consists of a coupled set of N transport equations. Only N=1 and N=2 are discussed in this paper. For larger N, although the accuracy could be improved, the calculation time is expected to significantly increase, which diminishes the advantage of the model in terms of its computational efficiency.

Transportation technology program: Strategic plan

NASA Astrophysics Data System (ADS)

1991-09-01

The purpose of this report is to define the technology program required to meet the transportation technology needs for current and future civil space missions. It is a part of an integrated plan, prepared by NASA in part in response to the Augustine Committee recommendations, to describe and advocate expanded and more aggressive efforts in the development of advanced space technologies. This expanded program will provide a technology basis for future space missions to which the U.S. aspires, and will help to regain technology leadership for the U.S. on a broader front. The six aspects of this integrated program/plan deal with focused technologies to support space sciences, exploration, transportation, platforms, and operations as well as provide a Research and Technology Base Program. This volume describes the technologies needed to support transportation systems, e.g., technologies needed for upgrades to current transportation systems and to provide reliable and efficient transportation for future space missions. The Office of Aeronautics, Exploration, and Technology (OAET) solicited technology needs from the major agency technology users and the aerospace industry community and formed a transportation technology team (appendix A) to develop a technology program to respond to those needs related to transportation technologies. This report addresses the results of that team activity. It is a strategic plan intended for use as a planning document rather than as a project management tool. It is anticipated that this document will be primarily utilized by research & technology (R&T) management at the various NASA Centers as well as by officials at NASA Headquarters and by industry in planning their corporate Independent Research and Development (IR&D) investments.

Transportation technology program: Strategic plan

NASA Technical Reports Server (NTRS)

1991-01-01

The purpose of this report is to define the technology program required to meet the transportation technology needs for current and future civil space missions. It is a part of an integrated plan, prepared by NASA in part in response to the Augustine Committee recommendations, to describe and advocate expanded and more aggressive efforts in the development of advanced space technologies. This expanded program will provide a technology basis for future space missions to which the U.S. aspires, and will help to regain technology leadership for the U.S. on a broader front. The six aspects of this integrated program/plan deal with focused technologies to support space sciences, exploration, transportation, platforms, and operations as well as provide a Research and Technology Base Program. This volume describes the technologies needed to support transportation systems, e.g., technologies needed for upgrades to current transportation systems and to provide reliable and efficient transportation for future space missions. The Office of Aeronautics, Exploration, and Technology (OAET) solicited technology needs from the major agency technology users and the aerospace industry community and formed a transportation technology team (appendix A) to develop a technology program to respond to those needs related to transportation technologies. This report addresses the results of that team activity. It is a strategic plan intended for use as a planning document rather than as a project management tool. It is anticipated that this document will be primarily utilized by research & technology (R&T) management at the various NASA Centers as well as by officials at NASA Headquarters and by industry in planning their corporate Independent Research and Development (IR&D) investments.

How Space Radiation Risk from Galactic Cosmic Rays at the International Space Station Relates to Nuclear Cross Sections

NASA Technical Reports Server (NTRS)

Lin, Zi-Wei; Adams, J. H., Jr.

2005-01-01

Space radiation risk to astronauts is a major obstacle for long term human space explorations. Space radiation transport codes have thus been developed to evaluate radiation effects at the International Space Station (ISS) and in missions to the Moon or Mars. We study how nuclear fragmentation processes in such radiation transport affect predictions on the radiation risk from galactic cosmic rays. Taking into account effects of the geomagnetic field on the cosmic ray spectra, we investigate the effects of fragmentation cross sections at different energies on the radiation risk (represented by dose-equivalent) from galactic cosmic rays behind typical spacecraft materials. These results tell us how the radiation risk at the ISS is related to nuclear cross sections at different energies, and consequently how to most efficiently reduce the physical uncertainty in our predictions on the radiation risk at the ISS.

Multidrug efflux transporter activity in sea urchin embryos:Does localization provide a diffusive advantage?

NASA Astrophysics Data System (ADS)

Song, Xianfeng; Setayeshgar, Sima; Cole, Bryan; Hamdoun, Amro; Epel, David

2008-03-01

Experiments have shown upregulation of multidrug efflux transporter activity approximately 30 min after fertilization in the sea urchin embryo [1]. These ATP-hydrolyzing transporter proteins pump moderately hydrophobic molecules out of the cell and represent the cell's first line of defense againstexogenous toxins. It has also been shown that transporters are moved in vesicles along microfilaments and localized to tips of microvilli prior to activation. We have constructed a geometrically realistic model of the embryo, including microvilli, to explore the functional role of this localization in the efficient elimination of toxins from the standpoint of diffusion. We compute diffusion of toxins in extracellular, membrane and intracellular spaces coupled with transporter activity, using experimentally derived values for physical parameters. For transporters uniformly distributed along microvilli and tip-localized transporters we compare regions in parameter space where each distribution provides diffusive advantage, and comment on the physically expected conditions. [1] A. M. Hamdoun, G. N. Cherr, T. A. Roepke and D. Epel, Developmental Biology 276 452 (2004).

Optimal perturbations for nonlinear systems using graph-based optimal transport

NASA Astrophysics Data System (ADS)

Grover, Piyush; Elamvazhuthi, Karthik

2018-06-01

We formulate and solve a class of finite-time transport and mixing problems in the set-oriented framework. The aim is to obtain optimal discrete-time perturbations in nonlinear dynamical systems to transport a specified initial measure on the phase space to a final measure in finite time. The measure is propagated under system dynamics in between the perturbations via the associated transfer operator. Each perturbation is described by a deterministic map in the measure space that implements a version of Monge-Kantorovich optimal transport with quadratic cost. Hence, the optimal solution minimizes a sum of quadratic costs on phase space transport due to the perturbations applied at specified times. The action of the transport map is approximated by a continuous pseudo-time flow on a graph, resulting in a tractable convex optimization problem. This problem is solved via state-of-the-art solvers to global optimality. We apply this algorithm to a problem of transport between measures supported on two disjoint almost-invariant sets in a chaotic fluid system, and to a finite-time optimal mixing problem by choosing the final measure to be uniform. In both cases, the optimal perturbations are found to exploit the phase space structures, such as lobe dynamics, leading to efficient global transport. As the time-horizon of the problem is increased, the optimal perturbations become increasingly localized. Hence, by combining the transfer operator approach with ideas from the theory of optimal mass transportation, we obtain a discrete-time graph-based algorithm for optimal transport and mixing in nonlinear systems.

Lunar transportation scenarios utilising the Space Elevator.

PubMed

Engel, Kilian A

2005-01-01

The Space Elevator (SE) concept has begun to receive an increasing amount of attention within the space community over the past couple of years and is no longer widely dismissed as pure science fiction. In light of the renewed interest in a, possibly sustained, human presence on the Moon and the fact that transportation and logistics form the bottleneck of many conceivable lunar missions, it is interesting to investigate what role the SE could eventually play in implementing an efficient Earth to Moon transportation system. The elevator allows vehicles to ascend from Earth and be injected into a trans-lunar trajectory without the use of chemical thrusters, thus eliminating gravity loss, aerodynamic loss and the need of high thrust multistage launch systems. Such a system therefore promises substantial savings of propellant and structural mass and could greatly increase the efficiency of Earth to Moon transportation. This paper analyzes different elevator-based trans-lunar transportation scenarios and characterizes them in terms of a number of benchmark figures. The transportation scenarios include direct elevator-launched trans-lunar trajectories, elevator launched trajectories via L1 and L2, as well as launch from an Earth-based elevator and subsequent rendezvous with lunar elevators placed either on the near or on the far side of the Moon. The benchmark figures by which the different transfer options are characterized and evaluated include release radius (RR), required delta v, transfer times as well as other factors such as accessibility of different lunar latitudes, frequency of launch opportunities and mission complexity. The performances of the different lunar transfer options are compared with each other as well as with the performance of conventional mission concepts, represented by Apollo. c2005 Elsevier Ltd. All rights reserved.

A Conceptual Approach for Optimising Bus Stop Spacing

NASA Astrophysics Data System (ADS)

Johar, Amita; Jain, S. S.; Garg, P. k.

2017-06-01

An efficient public transportation system is essential of any country. The growth, development and shape of the urban areas are mainly due to availability of good transportation (Shah et al. in Inst Town Plan India J 5(3):50-59, 1). In developing countries, like India, travel by local bus in a city is very common. The accidents, congestion, pollution and appropriate location of bus stops are the major problems arising in metropolitan cities. Among all the metropolitan cities in India, Delhi has highest percentage of growth of population and vehicles. Therefore, it is important to adopt efficient and effective ways to improve mobility in different metropolitan cities in order to overcome the problem and to reduce the number of private vehicles on the road. The primary objective of this paper is to present a methodology for developing a model for optimum bus stop spacing (OBSS). It describes the evaluation of existing urban bus route, data collection, development of model for optimizing urban bus route and application of model. In this work, the bus passenger generalized cost method is used to optimize the spacing between bus stops. For the development of model, a computer program is required to be written. The applicability of the model has been evaluated by taking the data of urban bus route of Delhi Transport Corporation (DTC) in Excel sheet in first phase. Later on, it is proposed to develop a programming in C++ language. The developed model is expected to be useful to transport planner for rational design of the spacing of bus stops to save travel time and to generalize operating cost. After analysis it is found that spacing between the bus stop comes out to be between 250 and 500 m. The Proposed Spacing of bus stops is done considering the points that they don't come nearer to metro/rail station, entry or exit of flyover and near traffic signal.

Computing observables in curved multifield models of inflation—A guide (with code) to the transport method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dias, Mafalda; Seery, David; Frazer, Jonathan, E-mail: m.dias@sussex.ac.uk, E-mail: j.frazer@sussex.ac.uk, E-mail: a.liddle@sussex.ac.uk

We describe how to apply the transport method to compute inflationary observables in a broad range of multiple-field models. The method is efficient and encompasses scenarios with curved field-space metrics, violations of slow-roll conditions and turns of the trajectory in field space. It can be used for an arbitrary mass spectrum, including massive modes and models with quasi-single-field dynamics. In this note we focus on practical issues. It is accompanied by a Mathematica code which can be used to explore suitable models, or as a basis for further development.

National Space Transportation and Support Study/technology requirements and plans

NASA Technical Reports Server (NTRS)

Walberg, G. D.; Gasperich, F. J., Jr.; Scheyhing, E. R.

1986-01-01

This paper presents a generic technology plan which has been developed as part of the National Space Transportation and Support Study. This program, which addresses a wide variety of potentially high payoff technology areas, is structured to promote both enhanced vehicle performance and greatly improved operational efficiency and includes both evolutionary and breakthrough technologies. The plan is presented in terms of disciplinary plan elements, which were developed by joint NASA/USAF disciplinary working groups, and as a set of demonstration projects which serve as focal points for the overall plan and drive the development of the many interrelated disciplinary activities.

Small space station electrical power system design concepts

NASA Technical Reports Server (NTRS)

Jones, G. M.; Mercer, L. N.

1976-01-01

A small manned facility, i.e., a small space station, placed in earth orbit by the Shuttle transportation system would be a viable, cost effective addition to the basic Shuttle system to provide many opportunities for R&D programs, particularly in the area of earth applications. The small space station would have many similarities with Skylab. This paper presents design concepts for an electrical power system (EPS) for the small space station based on Skylab experience, in-house work at Marshall Space Flight Center, SEPS (Solar Electric Propulsion Stage) solar array development studies, and other studies sponsored by MSFC. The proposed EPS would be a solar array/secondary battery system. Design concepts expressed are based on maximizing system efficiency and five year operational reliability. Cost, weight, volume, and complexity considerations are inherent in the concepts presented. A small space station EPS based on these concepts would be highly efficient, reliable, and relatively inexpensive.

Particle transport in low-energy ventilation systems. Part 2: Transients and experiments.

PubMed

Bolster, D T; Linden, P F

2009-04-01

Providing adequate indoor air quality while reducing energy consumption is a must for efficient ventilation system design. In this work, we study the transport of particulate contaminants in a displacement-ventilated space, using the idealized 'emptying filling box' model (P.F. Linden, G.F. Lane-serff and D.A. Smeed (1990) Emptying filling boxes: the fluid mechanics of natural ventilation, J. fluid Mech., 212, 309-335.). In this paper, we focused on transient contaminant transport by modeling three transient contamination scenarios, namely the so called 'step-up', 'step-down', and point source cases. Using analytical integral models and numerical models we studied the transient behavior of each of these three cases. We found that, on average, traditional and low-energy systems can be similar in overall pollutant removal efficiency, although quite different vertical gradients can exist. This plays an important role in estimating occupant exposure to contaminant. A series of laboratory experiments were conducted to validate the developed models. The results presented here illustrate that the source location plays a very important role in the distribution of contaminant concentration for spaces ventilated by low energy displacement-ventilation systems. With these results and the knowledge of typical contaminant sources for a given type of space practitioners can design or select more effective systems for the purpose at hand.

Thermal management system technology development for space station applications

NASA Technical Reports Server (NTRS)

Rankin, J. G.; Marshall, P. F.

1983-01-01

A short discussion of the history to date of the NASA thermal management system technology development program is presented, and the current status of several ongoing studies and hardware demonstration tasks is reported. One element of technology that is required for long-life, high-power orbital platforms/stations that is being developed is heat rejection and a space-constructable radiator system. Aspects of this project include high-efficiency fin concepts, a heat pipe quick-disconnect device, high-capacity heat pipes, and an alternate interface heat exchanger design. In the area of heat acquisition and transport, developments in a pumped two-phase transport loop, a capillary pumped transport loop using the concept of thermal utility are reported. An example of a thermal management system concept is provided.

Update of KSC activities for the space transportation system

NASA Technical Reports Server (NTRS)

Gray, R. H.

1979-01-01

The paper is a status report on the facilities and planned operations at the Kennedy Space Center (KSC) that will support Space Shuttle launches. The conversion of KSC facilities to support efficient and economical checkout and launch operations in the era of the Space Shuttle is nearing completion. The driving force behind the KSC effort has been the necessity of providing adequate and indispensable facilities and support systems at minimum cost. This required the optimum utilization of existing buildings, equipment and systems, both at KSC and at Air Force property on Cape Canaveral, as well as the construction of two major new facilities and several minor ones. The entirely new structures discussed are the Shuttle Landing Facility and Orbiter Processing Facility. KSC stands ready to provide the rapid reliable economical landing-to-launch processing needed to ensure the success of this new space transportation system.

Doping and electronic properties of GaAs grown by close-spaced vapor transport from powder sources for scalable III–V photovoltaics

DOE PAGES

Ritenour, Andrew J.; Boucher, Jason W.; DeLancey, Robert; ...

2014-09-01

The high balance-of-system costs of photovoltaic (PV) installations indicate that reductions in cell $/W costs alone are likely insufficient for PV electricity to reach grid parity unless energy conversion efficiency is also increased. Technologies which yield both high-efficiency cells (>25%) and maintain low costs are needed. GaAs and related III-V semiconductors are used in the highest-efficiency single- and multi-junction photovoltaics, but the technology is too expensive for non-concentrated terrestrial applications. This is due in part to the difficulty of scaling the metal-organic chemical vapor deposition (MOCVD) process, which relies on expensive reactors and employs toxic and pyrophoric gas-phase precursors suchmore » as arsine and trimethyl gallium, respectively. In this study, we describe GaAs films made by an alternative close-spaced vapor transport (CSVT) technique which is carried out at atmospheric pressure and requires only bulk GaAs, water vapor, and a temperature gradient in order to deposit crystalline films with similar electronic properties to that of GaAs deposited by MOCVD. CSVT is similar to the vapor transport process used to deposit CdTe thin films and is thus a potentially scalable low-cost route to GaAs thin films.« less

Green's function methods in heavy ion shielding

NASA Technical Reports Server (NTRS)

Wilson, John W.; Costen, Robert C.; Shinn, Judy L.; Badavi, Francis F.

1993-01-01

An analytic solution to the heavy ion transport in terms of Green's function is used to generate a highly efficient computer code for space applications. The efficiency of the computer code is accomplished by a nonperturbative technique extending Green's function over the solution domain. The computer code can also be applied to accelerator boundary conditions to allow code validation in laboratory experiments.

Efficient DFT+U calculations of ballistic electron transport: Application to Au monatomic chains with a CO impurity

NASA Astrophysics Data System (ADS)

Sclauzero, Gabriele; Dal Corso, Andrea

2013-02-01

An efficient method for computing the Landauer-Büttiker conductance of an open quantum system within DFT+U is presented. The Hubbard potential is included in electronic-structure and transport calculations as a simple renormalization of the nonlocal pseudopotential coefficients by restricting the integration for the onsite occupations within the cutoff spheres of the pseudopotential. We apply the methodology to the case of an Au monatomic chain in the presence of a CO molecule adsorbed on it. We show that the Hubbard U correction removes the spurious magnetization in the pristine Au chain at the equilibrium spacing, as well as the unphysical contribution of d electrons to the conductance, resulting in a single (spin-degenerate) transmission channel and a more realistic conductance of 1G0. We find that the conductance reduction due to CO adsorption is much larger for the atop site than for the bridge site, so that the general picture of electron transport in stretched Au chains given by the local density approximation remains valid at the equilibrium Au-Au spacing within DFT+U.

Applied research on 2-6 compound materials for heterojunction solar cells

NASA Technical Reports Server (NTRS)

Bube, R. H.

1975-01-01

Several II-VI heterojunctions show promise for photovoltaic conversion of solar energy. The three of greatest interest are p-CdTe/n-CdS, p-CdTe/n-ZnSe, and p-ZnTe/n-CdSe. Several p-CdTe/n-CdS heterojunction cells have been prepared by close spaced transport deposition of p-CdTe on single crystal n-CdS, and by two source vacuum evaporation of n-CdS on single crystal p-CdTe. Both types of cells, in an experimental stage, are quite comparable, exhibiting values of quantum efficiency between 0.5 and 0.9, open circuit voltages between 0.50 and 0.66 V, fill factors between 0.4 and 0.6, and solar efficiencies up to 4 percent. Cells of p-ZnTe/n-CdSe have also been made by close spaced vapor transport deposition of n-CdSe on single crystal p-ZnTe.

A white paper: Operational efficiency. New approaches to future propulsion systems

NASA Technical Reports Server (NTRS)

Rhodes, Russel; Wong, George

1991-01-01

Advanced launch systems for the next generation of space transportation systems (1995 to 2010) must deliver large payloads (125,000 to 500,000 lbs) to low earth orbit (LEO) at one tenth of today's cost, or 300 to 400 $/lb of payload. This cost represents an order of magnitude reduction from the Titan unmanned vehicle cost of delivering payload to orbit. To achieve this sizable reduction, the operations cost as well as the engine cost must both be lower than current engine system. The Advanced Launch System (ALS) is studying advanced engine designs, such as the Space Transportation Main Engine (STME), which has achieved notable reduction in cost. The results are presented of a current study wherein another level of cost reduction can be achieved by designing the propulsion module utilizing these advanced engines for enhanced operations efficiency and reduced operations cost.

Stochastic algorithm for simulating gas transport coefficients

NASA Astrophysics Data System (ADS)

Rudyak, V. Ya.; Lezhnev, E. V.

2018-02-01

The aim of this paper is to create a molecular algorithm for modeling the transport processes in gases that will be more efficient than molecular dynamics method. To this end, the dynamics of molecules are modeled stochastically. In a rarefied gas, it is sufficient to consider the evolution of molecules only in the velocity space, whereas for a dense gas it is necessary to model the dynamics of molecules also in the physical space. Adequate integral characteristics of the studied system are obtained by averaging over a sufficiently large number of independent phase trajectories. The efficiency of the proposed algorithm was demonstrated by modeling the coefficients of self-diffusion and the viscosity of several gases. It was shown that the accuracy comparable to the experimental one can be obtained on a relatively small number of molecules. The modeling accuracy increases with the growth of used number of molecules and phase trajectories.

Summary of 1989 - 1990 aeronautics design projects

NASA Technical Reports Server (NTRS)

1990-01-01

Four design projects were completed at Auburn University this year under the sponsorship of the NASA/Universities Space Research Association Advanced Design Program. The topics discussed are the design of a high speed civil transport; the design of a 79 passenger, high efficiency, commercial transport; the design of a low cost short takeof vertical landing export fighter; and the design of an ozone monitoring vehicle.

Transport of phase space densities through tetrahedral meshes using discrete flow mapping

NASA Astrophysics Data System (ADS)

Bajars, Janis; Chappell, David J.; Søndergaard, Niels; Tanner, Gregor

2017-01-01

Discrete flow mapping was recently introduced as an efficient ray based method determining wave energy distributions in complex built up structures. Wave energy densities are transported along ray trajectories through polygonal mesh elements using a finite dimensional approximation of a ray transfer operator. In this way the method can be viewed as a smoothed ray tracing method defined over meshed surfaces. Many applications require the resolution of wave energy distributions in three-dimensional domains, such as in room acoustics, underwater acoustics and for electromagnetic cavity problems. In this work we extend discrete flow mapping to three-dimensional domains by propagating wave energy densities through tetrahedral meshes. The geometric simplicity of the tetrahedral mesh elements is utilised to efficiently compute the ray transfer operator using a mixture of analytic and spectrally accurate numerical integration. The important issue of how to choose a suitable basis approximation in phase space whilst maintaining a reasonable computational cost is addressed via low order local approximations on tetrahedral faces in the position coordinate and high order orthogonal polynomial expansions in momentum space.

Geometry of matrix product states: Metric, parallel transport, and curvature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haegeman, Jutho, E-mail: jutho.haegeman@gmail.com; Verstraete, Frank; Faculty of Physics and Astronomy, University of Ghent, Krijgslaan 281 S9, 9000 Gent

2014-02-15

We study the geometric properties of the manifold of states described as (uniform) matrix product states. Due to the parameter redundancy in the matrix product state representation, matrix product states have the mathematical structure of a (principal) fiber bundle. The total space or bundle space corresponds to the parameter space, i.e., the space of tensors associated to every physical site. The base manifold is embedded in Hilbert space and can be given the structure of a Kähler manifold by inducing the Hilbert space metric. Our main interest is in the states living in the tangent space to the base manifold,more » which have recently been shown to be interesting in relation to time dependence and elementary excitations. By lifting these tangent vectors to the (tangent space) of the bundle space using a well-chosen prescription (a principal bundle connection), we can define and efficiently compute an inverse metric, and introduce differential geometric concepts such as parallel transport (related to the Levi-Civita connection) and the Riemann curvature tensor.« less

Reusable Hybrid Propellant Modules for Outer-Space Transport

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Mankins, John C.

2005-01-01

A report summarizes the concept of reusable hybrid propellant modules (HPMs), which would be used in outer space for long-term cryogenic storage of liquefied spacecraft-propellant gases, including for example, oxygen and hydrogen for combustion-based chemical rocket engines and xenon for electric thrusters. The HPM concept would provide the fundamental building block for an efficient, reusable in-space transportation system for both crewed and uncrewed missions. Each HPM would be equipped to implement an advanced zero-boil-off method of managing cryogenic fluids, and would include a fluid-transfer interface comprising standardized fittings that would be compatible with fittings on all supply facilities and on spacecraft to be supplied. The HPM, combined with a chemical or electric orbital transfer spacecraft, would provide an integrated propulsion system. HPMs would supply chemical propellant for time-critical transfers such as crewed missions, and utilize the more efficient electric-propulsion transfer vehicles to transport filled HPMs to the destinations and to return empty HPMs back to near-Earth orbits or other intermediate locations for replenishment and reuse. The HPM prepositioned using electric propulsion would provide the chemical propellant for the crew s return trip in a much more efficient manner than a chemical-only approach. The propellants to fill the HPMs would be delivered from the Earth or other initial supply locations to the intermediate locations by use of automated, compatible spacecraft designed specifically for that purpose. Additionally, multiple HPMs could be aggregated and positioned in orbits and on planets, moons, and asteroids to supply fluids to orbiting and interplanetary spacecraft.

Meson Production and Space Radiation

NASA Astrophysics Data System (ADS)

Norbury, John; Blattnig, Steve; Norman, Ryan; Aghara, Sukesh

Protecting astronauts from the harmful effects of space radiation is an important priority for long duration space flight. The National Council on Radiation Protection (NCRP) has recently recommended that pion and other mesons should be included in space radiation transport codes, especially in connection with the Martian atmosphere. In an interesting accident of nature, the galactic cosmic ray spectrum has its peak intensity near the pion production threshold. The Boltzmann transport equation is structured in such a way that particle production cross sec-tions are multiplied by particle flux. Therefore, the peak of the incident flux of the galactic cosmic ray spectrum is more important than other regions of the spectrum and cross sections near the peak are enhanced. This happens with pion cross sections. The MCNPX Monte-Carlo transport code now has the capability of transporting heavy ions, and by using a galactic cosmic ray spectrum as input, recent work has shown that pions contribute about twenty percent of the dose from galactic cosmic rays behind a shield of 20 g/cm2 aluminum and 30 g/cm2 water. It is therefore important to include pion and other hadron production in transport codes designed for space radiation studies, such as HZETRN. The status of experimental hadron production data for energies relevant to space radiation will be reviewed, as well as the predictive capa-bilities of current theoretical hadron production cross section and space radiation transport models. Charged pions decay into muons and neutrinos, and neutral pions decay into photons. An electromagnetic cascade is produced as these particles build up in a material. The cascade and transport of pions, muons, electrons and photons will be discussed as they relate to space radiation. The importance of other hadrons, such as kaons, eta mesons and antiprotons will be considered as well. Efficient methods for calculating cross sections for meson production in nucleon-nucleon and nucleus-nucleus reactions will be presented. The NCRP has also recom-mended that more attention should be paid to neutron and light ion transport. The coupling of neutrons, light ions, mesons and other hadrons will be discussed.

An assessment of advanced displays and controls technology applicable to future space transportation systems

NASA Technical Reports Server (NTRS)

Hatfield, Jack J.; Villarreal, Diana

1990-01-01

The topic of advanced display and control technology is addressed along with the major objectives of this technology, the current state of the art, major accomplishments, research programs and facilities, future trends, technology issues, space transportation systems applications and projected technology readiness for those applications. The holes that may exist between the technology needs of the transportation systems versus the research that is currently under way are addressed, and cultural changes that might facilitate the incorporation of these advanced technologies into future space transportation systems are recommended. Some of the objectives are to reduce life cycle costs, improve reliability and fault tolerance, use of standards for the incorporation of advancing technology, and reduction of weight, volume and power. Pilot workload can be reduced and the pilot's situational awareness can be improved, which would result in improved flight safety and operating efficiency. This could be accomplished through the use of integrated, electronic pictorial displays, consolidated controls, artificial intelligence, and human centered automation tools. The Orbiter Glass Cockpit Display is an example examined.

Evolved phase separation toward balanced charge transport and high efficiency in polymer solar cells.

PubMed

Fan, Haijun; Zhang, Maojie; Guo, Xia; Li, Yongfang; Zhan, Xiaowei

2011-09-01

Understanding effect of morphology on charge carrier transport within polymer/fullerene bulk heterojunction is necessary to develop high-performance polymer solar cells. In this work, we synthesized a new benzodithiophene-based polymer with good self-organization behavior as well as favorable morphology evolution of its blend films with PC(71)BM under improved processing conditions. Charge carrier transport behavior of blend films was characterized by space charge limited current method. Evolved blend film morphology by controlling blend composition and additive content gradually reaches an optimized state, featured with nanoscale fibrilla polymer phase in moderate size and balanced mobility ratio close to 1:1 for hole and electron. This optimized morphology toward more balanced charge carrier transport accounts for the best power conversion efficiency of 3.2%, measured under simulated AM 1.5 solar irradiation 100 mW/cm(2), through enhancing short circuit current and reducing geminate recombination loss.

Radiation Shielding for Space Flight

NASA Technical Reports Server (NTRS)

Blattnig, Steve R.; Norbury, John W.; Norman, Ryan B.

2003-01-01

A safe and efficient exploration of space requires an understanding of space radiations so that human life and sensitive equipment can be protected. On the way to these sensitive sites, the radiation is modified in both quality and quantity. Many of these modifications are thought to be due to the production of pions and muons in the interactions between the radiation and intervening matter. A method to predict the effects of the presence of these particles on the transport of radiation through materials is presented.

Overview of the National Aeronautics and Space Administration's Nondestructive Evaluation (NDE) Program

NASA Technical Reports Server (NTRS)

Generazio, Edward R.

2002-01-01

NASA's Office of Safety and Mission Assurance sponsors an Agency-wide NDE Program that supports Aeronautics and Space Transportation Technology, Human Exploration and Development of Space, Earth Science, and Space Science Enterprises. For each of these Enterprises, safety is the number one priority. Development of the next generation aero-space launch and transportation vehicles, satellites, and deep space probes have highlighted the enabling role that NDE plays in these advanced technology systems. Specific areas of advanced component development, component integrity, and structural heath management are critically supported by NDE technologies. The simultaneous goals of assuring safety, maintaining overall operational efficiency, and developing and utilizing revolutionary technologies to expand human activity and space-based commerce in the frontiers of air and space places increasing demands on the Agencies NDE infrastructure and resources. In this presentation, an overview of NASA's NDE Program will be presented, that includes a background and status of current Enterprise NDE issues, and the NDE investment areas being developed to meet Enterprise safety and mission assurance needs through the year 2009 and beyond.

Effects of MHD instabilities on neutral beam current drive

NASA Astrophysics Data System (ADS)

Podestà, M.; Gorelenkova, M.; Darrow, D. S.; Fredrickson, E. D.; Gerhardt, S. P.; White, R. B.

2015-05-01

Neutral beam injection (NBI) is one of the primary tools foreseen for heating, current drive (CD) and q-profile control in future fusion reactors such as ITER and a Fusion Nuclear Science Facility. However, fast ions from NBI may also provide the drive for energetic particle-driven instabilities (e.g. Alfvénic modes (AEs)), which in turn redistribute fast ions in both space and energy, thus hampering the control capabilities and overall efficiency of NB-driven current. Based on experiments on the NSTX tokamak (M. Ono et al 2000 Nucl. Fusion 40 557), the effects of AEs and other low-frequency magneto-hydrodynamic instabilities on NB-CD efficiency are investigated. A new fast ion transport model, which accounts for particle transport in phase space as required for resonant AE perturbations, is utilized to obtain consistent simulations of NB-CD through the tokamak transport code TRANSP. It is found that instabilities do indeed reduce the NB-driven current density over most of the plasma radius by up to ∼50%. Moreover, the details of the current profile evolution are sensitive to the specific model used to mimic the interaction between NB ions and instabilities. Implications for fast ion transport modeling in integrated tokamak simulations are briefly discussed.

Effects of MHD instabilities on neutral beam current drive

DOE PAGES

Podestà, M.; Gorelenkova, M.; Darrow, D. S.; ...

2015-04-17

One of the primary tools foreseen for heating, current drive (CD) and q-profile control in future fusion reactors such as ITER and a Fusion Nuclear Science Facility is the neutral beam injection (NBI). However, fast ions from NBI may also provide the drive for energetic particle-driven instabilities (e.g. Alfvénic modes (AEs)), which in turn redistribute fast ions in both space and energy, thus hampering the control capabilities and overall efficiency of NB-driven current. Based on experiments on the NSTX tokamak (M. Ono et al 2000 Nucl. Fusion 40 557), the effects of AEs and other low-frequency magneto-hydrodynamic instabilities on NB-CDmore » efficiency are investigated. When looking at the new fast ion transport model, which accounts for particle transport in phase space as required for resonant AE perturbations, is utilized to obtain consistent simulations of NB-CD through the tokamak transport code TRANSP. It is found that instabilities do indeed reduce the NB-driven current density over most of the plasma radius by up to ~50%. Moreover, the details of the current profile evolution are sensitive to the specific model used to mimic the interaction between NB ions and instabilities. Finally, implications for fast ion transport modeling in integrated tokamak simulations are briefly discussed.« less

Advanced Space Transportation Concepts and Propulsion Technologies for a New Delivery Paradigm

NASA Technical Reports Server (NTRS)

Robinson, John W.; McCleskey, Carey M.; Rhodes, Russel E.; Lepsch, Roger A.; Henderson, Edward M.; Joyner, Claude R., III; Levack, Daniel J. H.

2013-01-01

This paper describes Advanced Space Transportation Concepts and Propulsion Technologies for a New Delivery Paradigm. It builds on the work of the previous paper "Approach to an Affordable and Productive Space Transportation System". The scope includes both flight and ground system elements, and focuses on their compatibility and capability to achieve a technical solution that is operationally productive and also affordable. A clear and revolutionary approach, including advanced propulsion systems (advanced LOX rich booster engine concept having independent LOX and fuel cooling systems, thrust augmentation with LOX rich boost and fuel rich operation at altitude), improved vehicle concepts (autogeneous pressurization, turbo alternator for electric power during ascent, hot gases to purge system and keep moisture out), and ground delivery systems, was examined. Previous papers by the authors and other members of the Space Propulsion Synergy Team (SPST) focused on space flight system engineering methods, along with operationally efficient propulsion system concepts and technologies. This paper continues the previous work by exploring the propulsion technology aspects in more depth and how they may enable the vehicle designs from the previous paper. Subsequent papers will explore the vehicle design, the ground support system, and the operations aspects of the new delivery paradigm in greater detail.

Integrating Efficiency of Industry Processes and Practices Alongside Technology Effectiveness in Space Transportation Cost Modeling and Analysis

NASA Technical Reports Server (NTRS)

Zapata, Edgar

2012-01-01

This paper presents past and current work in dealing with indirect industry and NASA costs when providing cost estimation or analysis for NASA projects and programs. Indirect costs, when defined as those costs in a project removed from the actual hardware or software hands-on labor; makes up most of the costs of today's complex large scale NASA space/industry projects. This appears to be the case across phases from research into development into production and into the operation of the system. Space transportation is the case of interest here. Modeling and cost estimation as a process rather than a product will be emphasized. Analysis as a series of belief systems in play among decision makers and decision factors will also be emphasized to provide context.

Impact of Space Transportation System on planetary spacecraft and missions design

NASA Technical Reports Server (NTRS)

Barnett, P. M.

1975-01-01

Results of Jet Propulsion Laboratory (JPL) activities to define and understand alternatives for planetary spacecraft operations with the Space Transportation System (STS) are summarized. The STS presents a set of interfaces, operational alternatives, and constraints in the prelaunch, launch, and near-earth flight phases of a mission. Shuttle-unique features are defined and coupled with JPL's existing program experience to begin development of operationally efficient alternatives, concepts, and methods for STS-launched missions. The time frame considered begins with the arrival of the planetary spacecraft at Kennedy Space Center and includes prelaunch ground operations, Shuttle-powered flight, and near-earth operations, up to acquisition of the spacecraft signal by the Deep Space Network. The areas selected for study within this time frame were generally chosen because they represent the 'driving conditions' on planetary-mission as well as system design and operations.

Space Radiation Transport Code Development: 3DHZETRN

NASA Technical Reports Server (NTRS)

Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

2015-01-01

The space radiation transport code, HZETRN, has been used extensively for research, vehicle design optimization, risk analysis, and related applications. One of the simplifying features of the HZETRN transport formalism is the straight-ahead approximation, wherein all particles are assumed to travel along a common axis. This reduces the governing equation to one spatial dimension allowing enormous simplification and highly efficient computational procedures to be implemented. Despite the physical simplifications, the HZETRN code is widely used for space applications and has been found to agree well with fully 3D Monte Carlo simulations in many circumstances. Recent work has focused on the development of 3D transport corrections for neutrons and light ions (Z < 2) for which the straight-ahead approximation is known to be less accurate. Within the development of 3D corrections, well-defined convergence criteria have been considered, allowing approximation errors at each stage in model development to be quantified. The present level of development assumes the neutron cross sections have an isotropic component treated within N explicit angular directions and a forward component represented by the straight-ahead approximation. The N = 1 solution refers to the straight-ahead treatment, while N = 2 represents the bi-directional model in current use for engineering design. The figure below shows neutrons, protons, and alphas for various values of N at locations in an aluminum sphere exposed to a solar particle event (SPE) spectrum. The neutron fluence converges quickly in simple geometry with N > 14 directions. The improved code, 3DHZETRN, transports neutrons, light ions, and heavy ions under space-like boundary conditions through general geometry while maintaining a high degree of computational efficiency. A brief overview of the 3D transport formalism for neutrons and light ions is given, and extensive benchmarking results with the Monte Carlo codes Geant4, FLUKA, and PHITS are provided for a variety of boundary conditions and geometries. Improvements provided by the 3D corrections are made clear in the comparisons. Developments needed to connect 3DHZETRN to vehicle design and optimization studies will be discussed. Future theoretical development will relax the forward plus isotropic interaction assumption to more general angular dependence.

Recent Developments in Three Dimensional Radiation Transport Using the Green's Function Technique

NASA Technical Reports Server (NTRS)

Rockell, Candice; Tweed, John; Blattnig, Steve R.; Mertens, Christopher J.

2010-01-01

In the future, astronauts will be sent into space for longer durations of time compared to previous missions. The increased risk of exposure to dangerous radiation, such as Galactic Cosmic Rays and Solar Particle Events, is of great concern. Consequently, steps must be taken to ensure astronaut safety by providing adequate shielding. In order to better determine and verify shielding requirements, an accurate and efficient radiation transport code based on a fully three dimensional radiation transport model using the Green's function technique is being developed

Autonomous Space Shuttle

NASA Technical Reports Server (NTRS)

Siders, Jeffrey A.; Smith, Robert H.

2004-01-01

The continued assembly and operation of the International Space Station (ISS) is the cornerstone within NASA's overall Strategic P an. As indicated in NASA's Integrated Space Transportation Plan (ISTP), the International Space Station requires Shuttle to fly through at least the middle of the next decade to complete assembly of the Station, provide crew transport, and to provide heavy lift up and down mass capability. The ISTP reflects a tight coupling among the Station, Shuttle, and OSP programs to support our Nation's space goal . While the Shuttle is a critical component of this ISTP, there is a new emphasis for the need to achieve greater efficiency and safety in transporting crews to and from the Space Station. This need is being addressed through the Orbital Space Plane (OSP) Program. However, the OSP is being designed to "complement" the Shuttle as the primary means for crew transfer, and will not replace all the Shuttle's capabilities. The unique heavy lift capabilities of the Space Shuttle is essential for both ISS, as well as other potential missions extending beyond low Earth orbit. One concept under discussion to better fulfill this role of a heavy lift carrier, is the transformation of the Shuttle to an "un-piloted" autonomous system. This concept would eliminate the loss of crew risk, while providing a substantial increase in payload to orbit capability. Using the guidelines reflected in the NASA ISTP, the autonomous Shuttle a simplified concept of operations can be described as; "a re-supply of cargo to the ISS through the use of an un-piloted Shuttle vehicle from launch through landing". Although this is the primary mission profile, the other major consideration in developing an autonomous Shuttle is maintaining a crew transportation capability to ISS as an assured human access to space capability.

A Personnel Launch System for safe and efficient manned operations

NASA Astrophysics Data System (ADS)

Petro, Andrew J.; Andrews, Dana G.; Wetzel, Eric D.

1990-10-01

Several Conceptual designs for a simple, rugged Personnel Launch System (PLS) are presented. This system could transport people to and from Low Earth Orbit (LEO) starting in the late 1990's using a new modular Advanced Launch System (ALS) developed for the Space Exploration Initiative (SEI). The PLS is designed to be one element of a new space transportation architecture including heavy-lift cargo vehicles, lunar transfer vehicles, and multiple-role spcecraft such as the current Space Shuttle. The primary role of the PLS would be to deliver crews embarking on lunar or planetary missions to the Space Station, but it would also be used for earth-orbit sortie missions, space rescue missions, and some satellite servicing missions. The PLS design takes advantage of emerging electronic and structures technologies to offer a robust vehicle with autonomous operating and quick turnaround capabilities. Key features include an intact abort capability anywhere in the operating envelope, and elimination of all toxic propellants to streamline ground operations.

High-efficiency, low-temperature cesium diodes with lanthanum-hexaboride electrodes

NASA Technical Reports Server (NTRS)

Morris, J. F.

1974-01-01

Lanthanum hexaboride electrodes in 1700 K cesium diodes may triple power outputs compared with those demonstrated for nuclear thermionic space applications. Still greater relative gains seem possible for emitters below 1700 K. Further improvements in cesium diode performance should result from the lower collector temperatures allowed for earth and low power space duties. Decreased temperatures will lessen thermal transport losses that attend thermionic conversion mechanisms. Such advantages will add to those from collector Carnot and electrode effects. If plasma ignition difficulties impede diode temperature reductions, recycling small fractions of the output power could provide ionization. So high efficiency, low temperature cesium diodes with lanthanum hexaboride electrodes appear feasible.

Project LOCOST: Laser or Chemical Hybrid Orbital Space Transport

NASA Technical Reports Server (NTRS)

Dixon, Alan; Kost, Alicia; Lampshire, Gregory; Larsen, Rob; Monahan, Bob; Wright, Geoff

1990-01-01

A potential mission in the late 1990s is the servicing of spacecraft assets located in GEO. The Geosynchronous Operations Support Center (GeoShack) will be supported by a space transfer vehicle based at the Space Station (SS). The vehicle will transport cargo between the SS and the GeoShack. A proposed unmanned, laser or chemical hybrid orbital space transfer vehicle (LOCOST) can be used to efficiently transfer cargo between the two orbits. A preliminary design shows that an unmanned, laser/chemical hybrid vehicle results in the fuel savings needed while still providing fast trip times. The LOCOST vehicle receives a 12 MW laser beam from one Earth orbiting, solar pumped, iodide Laser Power Station (LPS). Two Energy Relay Units (ERU) provide laser beam support during periods of line-of-sight blockage by the Earth. The baseline mission specifies a 13 day round trip transfer time. The ship's configuration consist of an optical train, one hydrogen laser engine, two chemical engines, a 18 m by 29 m box truss, a mission-flexible payload module, and propellant tanks. Overall vehicle dry mass is 8,000 kg. Outbound cargo mass is 20,000 kg, and inbound cargo mass is 6,000 kg. The baseline mission needs 93,000 kg of propellants to complete the scenario. Fully fueled, outbound mission mass is 121,000 kg. A regeneratively cooled, single plasma, laser engine design producing a maximum of 768 N of thrust is utilized along with two traditional chemical engines. The payload module is designed to hold 40,000 kg of cargo, though the baseline mission specifies less. A proposed design of a laser/chemical hybrid vehicle provides a trip time and propellant efficient means to transport cargo from the SS to a GeoShack. Its unique, hybrid propulsion system provides safety through redundancy, allows baseline missions to be efficiently executed, while still allowing for the possibility of larger cargo transfers.

A role for high frequency superconducting devices in free space power transmission systems

NASA Technical Reports Server (NTRS)

Christian, Jose L., Jr.; Cull, Ronald C.

1988-01-01

Major advances in space power technology are being made in photovoltaic, solar thermal, and nuclear systems. Despite these advances, the power systems required by the energy and power intensive mission of the future will be massive due to the large collecting surfaces, large thermal management systems, and heavy shielding. Reducing this mass on board the space vehicle can result in significant benefits because of the high cost of transporting and moving mass about in space. An approach to this problem is beaming the power from a point where the massiveness of the power plant is not such a major concern. The viability of such an approach was already investigated. Efficient microwave power beam transmission at 2.45 GHz was demonstrated over short range. Higher frequencies are desired for efficient transmission over several hundred or thousand kilometers in space. Superconducting DC-RF conversion as well as RF-DC conversion offers exciting possibilities. Multivoltage power conditioning for multicavity high power RF tubes could be eliminated since only low voltages are required for Josephson junctions. Small, high efficiency receivers may be possible using the reverse Josephson effects. A conceptual receiving antenna design using superconducting devices to determine possible system operating efficiency is assessed. If realized, these preliminary assessments indicate a role for superconducting devices in millimeter and submillimeter free space power transmission systems.

A Common Communications, Navigation and Surveillance Infrastructure for Accommodating Space Vehicles in the Next Generation Air Transportation System

NASA Technical Reports Server (NTRS)

VanSuetendael, RIchard; Hayes, Alan; Birr, Richard

2008-01-01

Suborbital space flight and space tourism are new potential markets that could significantly impact the National Airspace System (NAS). Numerous private companies are developing space flight capabilities to capture a piece of an emerging commercial space transportation market. These entrepreneurs share a common vision that sees commercial space flight as a profitable venture. Additionally, U.S. space exploration policy and national defense will impose significant additional demands on the NAS. Air traffic service providers must allow all users fair access to limited airspace, while ensuring that the highest levels of safety, security, and efficiency are maintained. The FAA's Next Generation Air Transportation System (NextGen) will need to accommodate spacecraft transitioning to and from space through the NAS. To accomplish this, space and air traffic operations will need to be seamlessly integrated under some common communications, navigation and surveillance (CNS) infrastructure. As part of NextGen, the FAA has been developing the Automatic Dependent Surveillance Broadcast (ADS-B) which utilizes the Global Positioning System (GPS) to track and separate aircraft. Another key component of NextGen, System-Wide Information Management/ Network Enabled Operations (SWIM/NEO), is an open architecture network that will provide NAS data to various customers, system tools and applications. NASA and DoD are currently developing a space-based range (SBR) concept that also utilizes GPS, communications satellites and other CNS assets. The future SBR will have very similar utility for space operations as ADS-B and SWIM has for air traffic. Perhaps the FAA, NASA, and DoD should consider developing a common space-based CNS infrastructure to support both aviation and space transportation operations. This paper suggests specific areas of research for developing a CNS infrastructure that can accommodate spacecraft and other new types of vehicles as an integrated part of NextGen.

Technology Thresholds for Microgravity: Status and Prospects

NASA Technical Reports Server (NTRS)

Noever, D. A.

1996-01-01

The technological and economic thresholds for microgravity space research are estimated in materials science and biotechnology. In the 1990s, the improvement of materials processing has been identified as a national scientific priority, particularly for stimulating entrepreneurship. The substantial US investment at stake in these critical technologies includes six broad categories: aerospace, transportation, health care, information, energy, and the environment. Microgravity space research addresses key technologies in each area. The viability of selected space-related industries is critically evaluated and a market share philosophy is developed, namely that incremental improvements in a large markets efficiency is a tangible reward from space-based research.

Crew/Automation Interaction in Space Transportation Systems: Lessons Learned from the Glass Cockpit

NASA Technical Reports Server (NTRS)

Rudisill, Marianne

2000-01-01

The progressive integration of automation technologies in commercial transport aircraft flight decks - the 'glass cockpit' - has had a major, and generally positive, impact on flight crew operations. Flight deck automation has provided significant benefits, such as economic efficiency, increased precision and safety, and enhanced functionality within the crew interface. These enhancements, however, may have been accrued at a price, such as complexity added to crew/automation interaction that has been implicated in a number of aircraft incidents and accidents. This report briefly describes 'glass cockpit' evolution. Some relevant aircraft accidents and incidents are described, followed by a more detailed description of human/automation issues and problems (e.g., crew error, monitoring, modes, command authority, crew coordination, workload, and training). This paper concludes with example principles and guidelines for considering 'glass cockpit' human/automation integration within space transportation systems.

A Hitch-hiker's Guide to Stochastic Differential Equations. Solution Methods for Energetic Particle Transport in Space Physics and Astrophysics

NASA Astrophysics Data System (ADS)

Strauss, R. Du Toit; Effenberger, Frederic

2017-10-01

In this review, an overview of the recent history of stochastic differential equations (SDEs) in application to particle transport problems in space physics and astrophysics is given. The aim is to present a helpful working guide to the literature and at the same time introduce key principles of the SDE approach via "toy models". Using these examples, we hope to provide an easy way for newcomers to the field to use such methods in their own research. Aspects covered are the solar modulation of cosmic rays, diffusive shock acceleration, galactic cosmic ray propagation and solar energetic particle transport. We believe that the SDE method, due to its simplicity and computational efficiency on modern computer architectures, will be of significant relevance in energetic particle studies in the years to come.

HZETRN: A heavy ion/nucleon transport code for space radiations

NASA Technical Reports Server (NTRS)

Wilson, John W.; Chun, Sang Y.; Badavi, Forooz F.; Townsend, Lawrence W.; Lamkin, Stanley L.

1991-01-01

The galactic heavy ion transport code (GCRTRN) and the nucleon transport code (BRYNTRN) are integrated into a code package (HZETRN). The code package is computer efficient and capable of operating in an engineering design environment for manned deep space mission studies. The nuclear data set used by the code is discussed including current limitations. Although the heavy ion nuclear cross sections are assumed constant, the nucleon-nuclear cross sections of BRYNTRN with full energy dependence are used. The relation of the final code to the Boltzmann equation is discussed in the context of simplifying assumptions. Error generation and propagation is discussed, and comparison is made with simplified analytic solutions to test numerical accuracy of the final results. A brief discussion of biological issues and their impact on fundamental developments in shielding technology is given.

NASA is with you when you fly on This Week @NASA - November 21, 2014NASA invited social media members Nov. 18 and 19 to the agency’s Armstrong Flight Research Center for a two-day event highlighting the ways NASA is with you when you fly. The NASA social gave participants an exclusive look at the latest tools and technologies being developed to improve the efficiency, safety and adaptability of air transportation. Also, Next ISS crew trains, 3D printer installed in space, Asteroid capture technology test, Journey to Mars media day and more!

NASA Image and Video Library

2014-11-21

NASA invited social media members Nov. 18 and 19 to the agency’s Armstrong Flight Research Center for a two-day event highlighting the ways NASA is with you when you fly. The NASA social gave participants an exclusive look at the latest tools and technologies being developed to improve the efficiency, safety and adaptability of air transportation. Also, Next ISS crew trains, 3D printer installed in space, Asteroid capture technology test, Journey to Mars media day and more!

Numerical Simulation of Ion Transport in a Nano-Electrospray Ion Source at Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Wang, Wei; Bajic, Steve; John, Benzi; Emerson, David R.

2018-03-01

Understanding ion transport properties from the ion source to the mass spectrometer (MS) is essential for optimizing device performance. Numerical simulation helps in understanding of ion transport properties and, furthermore, facilitates instrument design. In contrast to previously reported numerical studies, ion transport simulations in a continuous injection mode whilst considering realistic space-charge effects have been carried out. The flow field was solved using Reynolds-averaged Navier-Stokes (RANS) equations, and a particle-in-cell (PIC) method was applied to solve a time-dependent electric field with local charge density. A series of ion transport simulations were carried out at different cone gas flow rates, ion source currents, and capillary voltages. A force evaluation analysis reveals that the electric force, the drag force, and the Brownian force are the three dominant forces acting on the ions. Both the experimental and simulation results indicate that cone gas flow rates of ≤250 slph (standard liter per hour) are important for high ion transmission efficiency, as higher cone gas flow rates reduce the ion signal significantly. The simulation results also show that the ion transmission efficiency reduces exponentially with an increased ion source current. Additionally, the ion loss due to space-charge effects has been found to be predominant at a higher ion source current, a lower capillary voltage, and a stronger cone gas counterflow. The interaction of the ion driving force, ion opposing force, and ion dispersion is discussed to illustrate ion transport mechanism in the ion source at atmospheric pressure. [Figure not available: see fulltext.

Numerical Simulation of Ion Transport in a Nano-Electrospray Ion Source at Atmospheric Pressure.

PubMed

Wang, Wei; Bajic, Steve; John, Benzi; Emerson, David R

2018-03-01

Understanding ion transport properties from the ion source to the mass spectrometer (MS) is essential for optimizing device performance. Numerical simulation helps in understanding of ion transport properties and, furthermore, facilitates instrument design. In contrast to previously reported numerical studies, ion transport simulations in a continuous injection mode whilst considering realistic space-charge effects have been carried out. The flow field was solved using Reynolds-averaged Navier-Stokes (RANS) equations, and a particle-in-cell (PIC) method was applied to solve a time-dependent electric field with local charge density. A series of ion transport simulations were carried out at different cone gas flow rates, ion source currents, and capillary voltages. A force evaluation analysis reveals that the electric force, the drag force, and the Brownian force are the three dominant forces acting on the ions. Both the experimental and simulation results indicate that cone gas flow rates of ≤250 slph (standard liter per hour) are important for high ion transmission efficiency, as higher cone gas flow rates reduce the ion signal significantly. The simulation results also show that the ion transmission efficiency reduces exponentially with an increased ion source current. Additionally, the ion loss due to space-charge effects has been found to be predominant at a higher ion source current, a lower capillary voltage, and a stronger cone gas counterflow. The interaction of the ion driving force, ion opposing force, and ion dispersion is discussed to illustrate ion transport mechanism in the ion source at atmospheric pressure. Graphical Abstract.

Propellantless Propulsion Technologies for In-Space Transportation

NASA Technical Reports Server (NTRS)

Johnson, Les; Cook, Stephen (Technical Monitor)

2001-01-01

In order to implement the ambitious science and exploration missions planned over the next several decades, improvements in in-space transportation and propulsion technologies must be achieved. For robotic exploration and science missions, increased efficiencies of future propulsion systems are critical to reduce overall life-cycle costs. Future missions will require 2 to 3 times more total change in velocity over their mission lives than the NASA Solar Electric Technology Application Readiness (NSTAR) demonstration on the Deep Space 1 mission. Rendezvous and return missions will require similar investments in in-space propulsion systems. New opportunities to explore beyond the outer planets and to the stars will require unparalleled technology advancement and innovation. The Advanced Space Transportation Program (ASTP) is investing in technologies to achieve a factor of 10 reduction in the cost of Earth orbital transportation and a factor of 2 or 3 reduction in propulsion system mass and travel time for planetary missions within the next 15 years. Since more than 70% of projected launches over the next 10 years will require propulsion systems capable of attaining destinations beyond Low Earth Orbit, investment in in-space technologies will benefit a large percentage of future missions. Some of the most promising technologies for achieving these goals use the environment of space itself for energy and propulsion and are generically called, "propellantless" because they do not require on-board fuel to achieve thrust. An overview of the state-of-the-art in propellantless propulsion technologies such as solar and plasma sails, electrodynamic and momentum transfer tethers, and aeroassist and aerocapture will be described. Results of recent earth-based technology demonstrations and space tests will also be discussed.

Hopping transport in the space-charge region of p-n structures with InGaN/GaN QWs as a source of excess 1/f noise and efficiency droop in LEDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bochkareva, N. I.; Ivanov, A. M.; Klochkov, A. V.

2015-06-15

It is shown that the emission efficiency and the 1/f noise level in light-emitting diodes with InGaN/GaN quantum wells correlate with how the differential resistance of a diode varies with increasing current. Analysis of the results shows that hopping transport via defect states across the n-type part of the space-charge region results in limitation of the current by the tunneling resistance at intermediate currents and shunting of the n-type barrier at high currents. The increase in the average number of tunneling electrons suppresses the 1/f current noise at intermediate currents. The strong growth in the density of current noise atmore » high currents, S{sub J} ∝ J{sup 3}, is attributed to a decrease in the average number of tunneling electrons as the n-type barrier decreases in height and width with increasing forward bias. The tunneling-recombination leakage current along extended defects grows faster than the tunneling injection current, which leads to emission efficiency droop.« less

Calculation of Supersonic Combustion Using Implicit Schemes

NASA Technical Reports Server (NTRS)

Yoon, Seokkwan; Kwak, Dochan (Technical Monitor)

2003-01-01

One of the technology goals of NASA for advanced space transportation is to develop highly efficient propulsion systems to reduce the cost of payload for space missions. Developments of rockets for the second generation Reusable Launch Vehicle (RLV) in the past several years have been focused on low-cost versions of conventional engines. However, recent changes in the Integrated Space Transportation Program to build a crew transportation vehicle to extend the life of the Space Shuttle fleet might suggest that air-breathing rockets could reemerge as a possible propulsion system for the third generation RLV to replace the Space Shuttle after 2015. The weight of the oxygen tank exceeds thirty percent of the total weight of the Space Shuttle at launch while the payload is only one percent of the total weight. The air-breathing rocket propulsion systems, which consume oxygen in the air, offer clear advantages by making vehicles lighter and more efficient. Experience in the National Aerospace Plane Program in the late 1980s indicates that scramjet engines can achieve high specific impulse for low hypersonic vehicle speeds. Whether taking a form of Rocket Based Combined Cycle (RBCC) or Turbine Based Combined Cycle (TBCC), the scramjet is an essential mode of operation for air-breathing rockets. It is well known that fuel-air mixing and rapid combustion are of crucial importance for the success of scramjet engines since the spreading rate of the supersonic mixing layer decreases as the Mach number increases. A factored form of the Gauss-Seidel relaxation method has been widely used in hypersonic flow research since its first application to non-equilibrium flows. However, difficulties in stability and convergence have been encountered when there is strong interaction between fluid motion and chemical reaction, such as multiple fuel injection problems. The present paper reports the results from investigation of the effect of modifications to the original algorithm on the performance for multiple injectors.

Selected tether applications in space: Phase 2. Executive summary

NASA Technical Reports Server (NTRS)

Thorson, M. H.; Lippy, L. J.

1985-01-01

The application of tether technology has the potential to increase the overall performance efficiency and capability of the integrated space operations and transportation systems through the decade of the 90s. The primary concepts for which significant economic benefits were identified are dependent on the space station as a storage device for angular momentum and as an operating base for the tether system. Concepts examined include: (1) tether deorbit of shuttle from space station; (2) tethered orbit insertion of a spacecraft from shuttle; (3) tethered platform deployed from space station; (4) tether-effected rendezvous of an OMV with a returning OTV; (5) electrodynamic tether as an auxiliary power source for space station; and (6) tether assisted launch of an OTV mission from space station.

WARP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergmann, Ryan M.; Rowland, Kelly L.

2017-04-12

WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed at UC Berkeley to efficiently execute on NVIDIA graphics processing unit (GPU) platforms. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo method, namely, that very few physical and geometrical simplifications are applied. WARP is able to calculate multiplication factors, neutron flux distributions (in both space and energy), and fission source distributions for time-independent neutron transport problems. It can run in both criticality or fixed source modes, but fixed source mode is currentlymore » not robust, optimized, or maintained in the newest version. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. The goal of developing WARP is to investigate algorithms that can grow into a full-featured, continuous energy, Monte Carlo neutron transport code that is accelerated by running on GPUs. The crux of the effort is to make Monte Carlo calculations faster while producing accurate results. Modern supercomputers are commonly being built with GPU coprocessor cards in their nodes to increase their computational efficiency and performance. GPUs execute efficiently on data-parallel problems, but most CPU codes, including those for Monte Carlo neutral particle transport, are predominantly task-parallel. WARP uses a data-parallel neutron transport algorithm to take advantage of the computing power GPUs offer.« less

Estimating long-term behavior of periodically driven flows without trajectory integration

NASA Astrophysics Data System (ADS)

Froyland, Gary; Koltai, Péter

2017-05-01

Periodically driven flows are fundamental models of chaotic behavior and the study of their transport properties is an active area of research. A well-known analytic construction is the augmentation of phase space with an additional time dimension; in this augmented space, the flow becomes autonomous or time-independent. We prove several results concerning the connections between the original time-periodic representation and the time-extended representation, focusing on transport properties. In the deterministic setting, these include single-period outflows and time-asymptotic escape rates from time-parameterized families of sets. We also consider stochastic differential equations with time-periodic advection term. In this stochastic setting one has a time-periodic generator (the differential operator given by the right-hand-side of the corresponding time-periodic Fokker-Planck equation). We define in a natural way an autonomous generator corresponding to the flow on time-extended phase space. We prove relationships between these two generator representations and use these to quantify decay rates of observables and to determine time-periodic families of sets with slow escape rate. Finally, we use the generator on the time-extended phase space to create efficient numerical schemes to implement the various theoretical constructions. These ideas build on the work of Froyland et al (2013 SIAM J. Numer. Anal. 51 223-47), and no expensive time integration is required. We introduce an efficient new hybrid approach, which treats the space and time dimensions separately.

Effects of space flight, clinorotation, and centrifugation on the substrate utilization efficiency of E. coli

NASA Technical Reports Server (NTRS)

Brown, Robert B.; Klaus, D.; Todd, P.

2002-01-01

Cultures of Escherichia coli grown in space reached a 25% higher average final cell population than those in comparably matched ground controls (p<0.05). However, both groups consumed the same quantity of glucose, which suggests that space flight not only stimulated bacterial growth as has been previously reported, but also resulted in a 25% more efficient utilization of the available nutrients. Supporting experiments performed in "simulated weightlessness" under clinorotation produced similar trends of increased growth and efficiency, but to a lesser extent in absolute values. These experiments resulted in increases of 12% and 9% in average final cell population (p<0.05), while the efficiency of substrate utilization improved by 6% and 9% relative to static controls (p=0.12 and p<0.05, respectively). In contrast, hypergravity, produced by centrifugation, predictably resulted in the opposite effect--a decrease of 33% to 40% in final cell numbers with corresponding 29% to 40% lower net growth efficiencies (p<0.01). Collectively, these findings support the hypothesis that the increased bacterial growth observed in weightlessness is a result of reduced extracellular mass transport that occurs in the absence of sedimentation and buoyancy-driven convection, which consequently also improves substrate utilization efficiency in suspended cultures.

Plant mineral nutrition, gas exchange and photosynthesis in space: A review

NASA Astrophysics Data System (ADS)

Wolff, S. A.; Coelho, L. H.; Zabrodina, M.; Brinckmann, E.; Kittang, A.-I.

2013-02-01

Successful growth and development of higher plants in space rely on adequate availability and uptake of water and nutrients, and efficient energy distribution through photosynthesis and gas exchange. In the present review, literature has been reviewed to assemble the relevant knowledge within space plant research for future planetary missions. Focus has been on fractional gravity, space radiation, magnetic fields and ultimately a combined effect of these factors on gas exchange, photosynthesis and transport of water and solutes. Reduced gravity prevents buoyancy driven thermal convection in the physical environment around the plant and alters transport and exchange of gases and liquids between the plant and its surroundings. In space experiments, indications of root zone hypoxia have frequently been reported, but studies on the influences of the space environment on plant nutrition and water transport are limited or inconclusive. Some studies indicate that uptake of potassium is elevated when plants are grown under microgravity conditions. Based on the current knowledge, gas exchange, metabolism and photosynthesis seem to work properly in space when plants are provided with a well stirred atmosphere and grown at moderate light levels. Effects of space radiation on plant metabolism, however, have not been studied so far in orbit. Ground experiments indicated that shielding from the Earth's magnetic field alters plant gas exchange and metabolism, though more studies are required to understand the effects of magnetic fields on plant growth. It has been shown that plants can grow and reproduce in the space environment and adapt to space conditions. However, the influences of the space environment may result in a long term effect over multiple generations or have an impact on the plants' role as food and part of a regenerative life support system. Suggestions for future plant biology research in space are discussed.

Space Transportation System Western Launch Site Construction Management Information System - A Case Study.

DTIC Science & Technology

1979-09-01

The Corps of Engineers Management Information System (COEMIS) is used by the Corps of Engineers in their role as Construction Agents on Air Force...California. The research concluded that the Corps of Engineers Management Information System can be an effective, efficient management tool which has the

Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology Into Human Exploration and Operations Mission Directorate Projects for 2016

NASA Technical Reports Server (NTRS)

Nguyen, Hung D.; Steele, Gynelle C.

2017-01-01

This report is intended to help NASA program and project managers incorporate Small Business Innovation Research Small Business Technology Transfer (SBIR/STTR) technologies into NASA Human Exploration and Operations Mission Directorate (HEOMD) projects. Other Government and commercial projects managers can also find this useful. Space Transportation; Life Support and Habitation Systems; Extra-Vehicular Activity; High EfficiencySpace Power; Human Exploration and Operations Mission,

Design and fabrication of metallic thermal protection systems for aerospace vehicles

NASA Technical Reports Server (NTRS)

Varisco, A.; Bell, P.; Wolter, W.

1978-01-01

A program was conducted to develop a lightweight, efficient metallic thermal protection system (TPS) for application to future shuttle-type reentry vehicles, advanced space transports, and hypersonic cruise vehicles. Technical requirements were generally derived from the space shuttle. A corrugation-stiffened beaded-skin TPS design was used as a baseline. The system was updated and modified to incorporate the latest technology developments and design criteria. The primary objective was to minimize mass for the total system.

Hybrid Power Management Program Continued

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2002-01-01

Hybrid Power Management (HPM) is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors and photovoltaics. HPM has extremely wide potential with applications including power-generation, transportation, biotechnology, and space power systems. It may significantly alleviate global energy concerns, improve the environment, and stimulate the economy.

Shape Classification Using Wasserstein Distance for Brain Morphometry Analysis.

PubMed

Su, Zhengyu; Zeng, Wei; Wang, Yalin; Lu, Zhong-Lin; Gu, Xianfeng

2015-01-01

Brain morphometry study plays a fundamental role in medical imaging analysis and diagnosis. This work proposes a novel framework for brain cortical surface classification using Wasserstein distance, based on uniformization theory and Riemannian optimal mass transport theory. By Poincare uniformization theorem, all shapes can be conformally deformed to one of the three canonical spaces: the unit sphere, the Euclidean plane or the hyperbolic plane. The uniformization map will distort the surface area elements. The area-distortion factor gives a probability measure on the canonical uniformization space. All the probability measures on a Riemannian manifold form the Wasserstein space. Given any 2 probability measures, there is a unique optimal mass transport map between them, the transportation cost defines the Wasserstein distance between them. Wasserstein distance gives a Riemannian metric for the Wasserstein space. It intrinsically measures the dissimilarities between shapes and thus has the potential for shape classification. To the best of our knowledge, this is the first. work to introduce the optimal mass transport map to general Riemannian manifolds. The method is based on geodesic power Voronoi diagram. Comparing to the conventional methods, our approach solely depends on Riemannian metrics and is invariant under rigid motions and scalings, thus it intrinsically measures shape distance. Experimental results on classifying brain cortical surfaces with different intelligence quotients demonstrated the efficiency and efficacy of our method.

Shape Classification Using Wasserstein Distance for Brain Morphometry Analysis

PubMed Central

Su, Zhengyu; Zeng, Wei; Wang, Yalin; Lu, Zhong-Lin; Gu, Xianfeng

2015-01-01

Brain morphometry study plays a fundamental role in medical imaging analysis and diagnosis. This work proposes a novel framework for brain cortical surface classification using Wasserstein distance, based on uniformization theory and Riemannian optimal mass transport theory. By Poincare uniformization theorem, all shapes can be conformally deformed to one of the three canonical spaces: the unit sphere, the Euclidean plane or the hyperbolic plane. The uniformization map will distort the surface area elements. The area-distortion factor gives a probability measure on the canonical uniformization space. All the probability measures on a Riemannian manifold form the Wasserstein space. Given any 2 probability measures, there is a unique optimal mass transport map between them, the transportation cost defines the Wasserstein distance between them. Wasserstein distance gives a Riemannian metric for the Wasserstein space. It intrinsically measures the dissimilarities between shapes and thus has the potential for shape classification. To the best of our knowledge, this is the first work to introduce the optimal mass transport map to general Riemannian manifolds. The method is based on geodesic power Voronoi diagram. Comparing to the conventional methods, our approach solely depends on Riemannian metrics and is invariant under rigid motions and scalings, thus it intrinsically measures shape distance. Experimental results on classifying brain cortical surfaces with different intelligence quotients demonstrated the efficiency and efficacy of our method. PMID:26221691

A simple quantum mechanical treatment of scattering in nanoscale transistors

NASA Astrophysics Data System (ADS)

Venugopal, R.; Paulsson, M.; Goasguen, S.; Datta, S.; Lundstrom, M. S.

2003-05-01

We present a computationally efficient, two-dimensional quantum mechanical simulation scheme for modeling dissipative electron transport in thin body, fully depleted, n-channel, silicon-on-insulator transistors. The simulation scheme, which solves the nonequilibrium Green's function equations self consistently with Poisson's equation, treats the effect of scattering using a simple approximation inspired by the "Büttiker probes," often used in mesoscopic physics. It is based on an expansion of the active device Hamiltonian in decoupled mode space. Simulation results are used to highlight quantum effects, discuss the physics of scattering and to relate the quantum mechanical quantities used in our model to experimentally measured low field mobilities. Additionally, quantum boundary conditions are rigorously derived and the effects of strong off-equilibrium transport are examined. This paper shows that our approximate treatment of scattering, is an efficient and useful simulation method for modeling electron transport in nanoscale, silicon-on-insulator transistors.

Contour integral method for obtaining the self-energy matrices of electrodes in electron transport calculations

NASA Astrophysics Data System (ADS)

Iwase, Shigeru; Futamura, Yasunori; Imakura, Akira; Sakurai, Tetsuya; Tsukamoto, Shigeru; Ono, Tomoya

2018-05-01

We propose an efficient computational method for evaluating the self-energy matrices of electrodes to study ballistic electron transport properties in nanoscale systems. To reduce the high computational cost incurred in large systems, a contour integral eigensolver based on the Sakurai-Sugiura method combined with the shifted biconjugate gradient method is developed to solve an exponential-type eigenvalue problem for complex wave vectors. A remarkable feature of the proposed algorithm is that the numerical procedure is very similar to that of conventional band structure calculations. We implement the developed method in the framework of the real-space higher-order finite-difference scheme with nonlocal pseudopotentials. Numerical tests for a wide variety of materials validate the robustness, accuracy, and efficiency of the proposed method. As an illustration of the method, we present the electron transport property of the freestanding silicene with the line defect originating from the reversed buckled phases.

Progress in aeronautical research and technology applicable to civil air transports

NASA Technical Reports Server (NTRS)

Bower, R. E.

1981-01-01

Recent progress in the aeronautical research and technology program being conducted by the United States National Aeronautics and Space Administration is discussed. Emphasis is on computational capability, new testing facilities, drag reduction, turbofan and turboprop propulsion, noise, composite materials, active controls, integrated avionics, cockpit displays, flight management, and operating problems. It is shown that this technology is significantly impacting the efficiency of the new civil air transports. The excitement of emerging research promises even greater benefits to future aircraft developments.

Transport properties of triarylamine based dendrimers studied by space charge limited current transients

NASA Astrophysics Data System (ADS)

Szymanski, Marek Z.; Kulszewicz-Bajer, Irena; Faure-Vincent, Jérôme; Djurado, David

2012-08-01

We have studied hole transport in triarylamine based dendrimer using space-charge-limited current transient technique. A mobility of 8 × 10-6 cm2/(V s) and a characteristic detrapping time of about 100 ms have been obtained. We found that quasi-ohmic contact is formed with gold. The obtained mobility differs from the apparent one given by the analysis of stationary current-voltage characteristics because of a limited contact efficiency. The comparison between transients obtained from fresh and aged samples reveals no change in mobility with aging. The deterioration of electrical properties is exclusively caused by trap formation and accumulation of ionic conducting impurities. Finally, repeated transient measurements have been applied to analyze the dynamics of charge trapping process.

Atmospheric rendezvous feasibility study

NASA Technical Reports Server (NTRS)

Schaezler, A. D.

1972-01-01

A study was carried out to determine the feasibility of using atmospheric rendezvous to increase the efficiency of space transportation and to determine the most effective implementation. It is concluded that atmospheric rendezvous is feasible and can be utilized in a space transportation system to reduce size of the orbiter vehicle, provide a powered landing with go-around capability for every mission, and achieve lateral range performance that exceeds requirements. A significantly lighter booster and reduced launch fuel requirements are additional benefits that can be realized with a system that includes a large subsonic airplane for recovery of the orbiter. Additional reduction in booster size is possible if the airplane is designed for recovery of the booster by towing. An airplane about the size of the C-5A is required.

A streamline splitting pore-network approach for computationally inexpensive and accurate simulation of transport in porous media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehmani, Yashar; Oostrom, Martinus; Balhoff, Matthew

2014-03-20

Several approaches have been developed in the literature for solving flow and transport at the pore-scale. Some authors use a direct modeling approach where the fundamental flow and transport equations are solved on the actual pore-space geometry. Such direct modeling, while very accurate, comes at a great computational cost. Network models are computationally more efficient because the pore-space morphology is approximated. Typically, a mixed cell method (MCM) is employed for solving the flow and transport system which assumes pore-level perfect mixing. This assumption is invalid at moderate to high Peclet regimes. In this work, a novel Eulerian perspective on modelingmore » flow and transport at the pore-scale is developed. The new streamline splitting method (SSM) allows for circumventing the pore-level perfect mixing assumption, while maintaining the computational efficiency of pore-network models. SSM was verified with direct simulations and excellent matches were obtained against micromodel experiments across a wide range of pore-structure and fluid-flow parameters. The increase in the computational cost from MCM to SSM is shown to be minimal, while the accuracy of SSM is much higher than that of MCM and comparable to direct modeling approaches. Therefore, SSM can be regarded as an appropriate balance between incorporating detailed physics and controlling computational cost. The truly predictive capability of the model allows for the study of pore-level interactions of fluid flow and transport in different porous materials. In this paper, we apply SSM and MCM to study the effects of pore-level mixing on transverse dispersion in 3D disordered granular media.« less

Multiplexed immunosensing and kinetics monitoring in nanofluidic devices with highly enhanced target capture efficiency

PubMed Central

Lin, Yii-Lih; Huang, Yen-Jun; Teerapanich, Pattamon; Leïchlé, Thierry

2016-01-01

Nanofluidic devices promise high reaction efficiency and fast kinetic responses due to the spatial constriction of transported biomolecules with confined molecular diffusion. However, parallel detection of multiple biomolecules, particularly proteins, in highly confined space remains challenging. This study integrates extended nanofluidics with embedded protein microarray to achieve multiplexed real-time biosensing and kinetics monitoring. Implementation of embedded standard-sized antibody microarray is attained by epoxy-silane surface modification and a room-temperature low-aspect-ratio bonding technique. An effective sample transport is achieved by electrokinetic pumping via electroosmotic flow. Through the nanoslit-based spatial confinement, the antigen-antibody binding reaction is enhanced with ∼100% efficiency and may be directly observed with fluorescence microscopy without the requirement of intermediate washing steps. The image-based data provide numerous spatially distributed reaction kinetic curves and are collectively modeled using a simple one-dimensional convection-reaction model. This study represents an integrated nanofluidic solution for real-time multiplexed immunosensing and kinetics monitoring, starting from device fabrication, protein immobilization, device bonding, sample transport, to data analysis at Péclet number less than 1. PMID:27375819

Tailoring Quantum Dot Assemblies to Extend Exciton Coherence Times and Improve Exciton Transport

NASA Astrophysics Data System (ADS)

Seward, Kenton; Lin, Zhibin; Lusk, Mark

2012-02-01

The motion of excitons through nanostructured assemblies plays a central role in a wide range of physical phenomena including quantum computing, molecular electronics, photosynthetic processes, excitonic transistors and light emitting diodes. All of these technologies are severely handicapped, though, by quasi-particle lifetimes on the order of a nanosecond. The movement of excitons must therefore be as efficient as possible in order to move excitons meaningful distances. This is problematic for assemblies of small Si quantum dots (QDs), where excitons quickly localize and entangle with dot phonon modes. Ensuing exciton transport is then characterized by a classical random walk reduced to very short distances because of efficient recombination. We use a combination of master equation (Haken-Strobl) formalism and density functional theory to estimate the rate of decoherence in Si QD assemblies and its impact on exciton mobility. Exciton-phonon coupling and Coulomb interactions are calculated as a function of dot size, spacing and termination to minimize the rate of intra-dot phonon entanglement. This extends the time over which more efficient exciton transport, characterized by partial coherence, can be maintained.

Solar heating system final design package

NASA Technical Reports Server (NTRS)

1979-01-01

The system is composed of a warm air collector, a logic control unit and a universal switching and transport unit. The collector was originally conceived and designed as an integrated roof/wall system and therefore provides a dual function in the structure. The collector serves both as a solar energy conversion system and as a structural weather resistant skin. The control unit provides totally automatic control over the operation of the system. It receives input data from sensor probes in collectors, storage and living space. The logic was designed so as to make maximum use of solar energy and minimize use of conventional energy. The transport and switching unit is a high-efficiency air-handling system equipped with gear motor valves that respond to outputs from the control system. The fan unit was designed for maximum durability and efficiency in operation, and has permanently lubricated ball bearings and excellent air-handling efficiency.

Time-reversal-symmetric single-photon wave packets for free-space quantum communication.

PubMed

Trautmann, N; Alber, G; Agarwal, G S; Leuchs, G

2015-05-01

Readout and retrieval processes are proposed for efficient, high-fidelity quantum state transfer between a matter qubit, encoded in the level structure of a single atom or ion, and a photonic qubit, encoded in a time-reversal-symmetric single-photon wave packet. They are based on controlling spontaneous photon emission and absorption of a matter qubit on demand in free space by stimulated Raman adiabatic passage. As these processes do not involve mode selection by high-finesse cavities or photon transport through optical fibers, they offer interesting perspectives as basic building blocks for free-space quantum-communication protocols.

Microwave transmission system for space power

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1976-01-01

A small total system model and a large subsystem element similar to those that could be eventually used for wireless power transmission experiments in space have been successfully demonstrated by NASA. The short range, relatively low-power laboratory system achieved a dc-to-dc transmission efficiency of 54%. A separate high-power-level receiving subsystem, tested over a 1.54-km range at Goldstone, California, has achieved the transportation of over 30 kW of dc output power. Both tests used 12-cm wavelength microwaves.

Space Shuttle capabilities, constraints, and cost

NASA Technical Reports Server (NTRS)

Lee, C. M.

1980-01-01

The capabilities, constraints, and costs of the Space Transportation System (STS), which combines reusable and expendable components, are reviewed, and an overview of the current planning activities for operating the STS in an efficient and cost-effective manner is presented. Traffic forecasts, performance constraints and enhancements, and potential new applications are discussed. Attention is given to operating costs, pricing policies, and the steps involved in 'getting on board', which includes all the interfaces between NASA and the users necessary to come to launch service agreements.

Helium-3 Mining Aerostats in the Atmospheres of the Outer Planets

NASA Technical Reports Server (NTRS)

VanCleve, Jeffrey E.; Grillmair, Carl; Hanna, Mark; Reinert, Rich

2005-01-01

Imagine an interplanetary future where: a) d-He3 fusion produces most of Earth s energy needs without radioactivity or carbon emissions; b) Space transportation has been revolutionized by an efficient fusion propulsion system with exhaust velocity up to 0.088 c; c) Space commerce is stimulated by the existence of an interplanetary cargo worth $3-M a kilogram; and d) Unmanned probes travel to the nearest star systems with flight times less than a human lifetime.

Comparison of Radiation Transport Codes, HZETRN, HETC and FLUKA, Using the 1956 Webber SPE Spectrum

NASA Technical Reports Server (NTRS)

Heinbockel, John H.; Slaba, Tony C.; Blattnig, Steve R.; Tripathi, Ram K.; Townsend, Lawrence W.; Handler, Thomas; Gabriel, Tony A.; Pinsky, Lawrence S.; Reddell, Brandon; Clowdsley, Martha S.;

Fusion energy for space missions in the 21st century: Executive summary

NASA Technical Reports Server (NTRS)

Schulze, Norman R.

1991-01-01

Future space missions were hypothesized and analyzed, and the energy source of their accomplishment investigated. The missions included manned Mars, scientific outposts to and robotic sample return missions from the outer planets and asteroids, as well as fly-by and rendezvous missions with the Oort Cloud and the nearest star, Alpha Centauri. Space system parametric requirements and operational features were established. The energy means for accomplishing missions where delta v requirements range from 90 km/sec to 30,000 km/sec (High Energy Space Mission) were investigated. The need to develop a power space of this magnitude is a key issue to address if the U.S. civil space program is to continue to advance as mandated by the National Space Policy. Potential energy options which could provide the propulsion and electrical power system and operational requirements were reviewed and evaluated. Fusion energy was considered to be the preferred option and was analyzed in depth. Candidate fusion fuels were evaluated based upon the energy output and neutron flux. Additionally, fusion energy can offer significant safety, environmental, economic, and operational advantages. Reactors exhibiting a highly efficient use of magnetic fields for space use while at the same time offering efficient coupling to an exhaust propellant or to a direct energy convertor for efficient electrical production were examined. Near term approaches were identified. A strategy that will produce fusion powered vehicles as part of the space transportation infrastructure was developed. Space program resources must be directed toward this issue as a matter of the top policy priority.

Modular System to Enable Extravehicular Activity

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2011-01-01

The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space system (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower earth orbit (BLEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular extravehicular activity system (MEVAS) that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs and define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option was included to make use of the developing suitport technologies.

A mathematical model for adaptive vein formation during exploratory migration of Physarum polycephalum: routing while scouting

NASA Astrophysics Data System (ADS)

Schenz, Daniel; Shima, Yasuaki; Kuroda, Shigeru; Nakagaki, Toshiyuki; Ueda, Kei-Ichi

2017-11-01

Exploring free space (scouting) efficiently is a non-trivial task for organisms of limited perception, such as the amoeboid Physarum polycephalum. However, the strategy behind its exploratory behaviour has not yet been characterised. In this organism, as the extension of the frontal part into free space is directly supported by the transport of body mass from behind, the formation of transport channels (routing) plays the main role in that strategy. Here, we study the organism’s exploration by letting it expand through a corridor of constant width. When turning at a corner of the corridor, the organism constructed a main transport vein tracing a centre-in-centre line. We argue that this is efficient for mass transport due to its short length, and check this intuition with a new algorithm that can predict the main vein’s position from the frontal tip’s progression. We then present a numerical model that incorporates reaction-diffusion dynamics for the behaviour of the organism’s growth front and current reinforcement dynamics for the formation of the vein network in its wake, as well as interactions between the two. The accuracy of the model is tested against the behaviour of the real organism and the importance of the interaction between growth tip dynamics and vein network development is analysed by studying variants of the model. We conclude by offering a biological interpretation of the well-known current reinforcement rule in the context of the natural exploratory behaviour of Physarum polycephalum.

Radiation shielding materials characterization in the MoMa-Count program and further evolutions

NASA Astrophysics Data System (ADS)

Lobascio, Cesare

In the frame of the space research programme MoMa (From Molecules to Man) -Count (Coun-termeasures), funded by the Italian Space Agency, multi-functional protections for human space exploration have been investigated, paying particular attention to flexible materials, selected also for their excellent structural, thermal and ballistic performances. Flexible materials such as Kevlar R are qualified for space application, but have poorly known space radiation prop-erties, with consequent uncertainties about their shielding efficiency against the radiation en-vironment. The necessary evaluation of their shielding efficiency has been chiefly based on dedicated ground experiments in accelerators, supplemented by Monte Carlo simulations of the particle transport in the materials or multi-layers. In addition, flight experiments have been performed in Low Earth Orbit (LEO), onboard the International Space Station (ISS) and the re-entry capsule Foton, to measure the shielding behaviour in the actual operating environment of space, via dedicated detectors and dosimeters. This paper aims at presenting the results and lessons learned accrued within the MoMa-Count program, as well as the future actions planned for improving radiation shielding in long duration human exploration missions.

The Space Communications Protocol Standards Program

NASA Technical Reports Server (NTRS)

Jeffries, Alan; Hooke, Adrian J.

1994-01-01

In the fall of 1992 NASA and the Department of Defense chartered a technical team to explore the possibility of developing a common set of space data communications standards for potential dual-use across the U.S. national space mission support infrastructure. The team focused on the data communications needs of those activities associated with on-lined control of civil and military aircraft. A two-pronged approach was adopted: a top-down survey of representative civil and military space data communications requirements was conducted; and a bottom-up analysis of available standard data communications protocols was performed. A striking intersection of civil and military space mission requirements emerged, and an equally striking consensus on the approach towards joint civil and military space protocol development was reached. The team concluded that wide segments of the U.S. civil and military space communities have common needs for: (1) an efficient file transfer protocol; (2) various flavors of underlying data transport service; (3) an optional data protection mechanism to assure end-to-end security of message exchange; and (4) an efficient internetworking protocol. These recommendations led to initiating a program to develop a suite of protocols based on these findings. This paper describes the current status of this program.

Mutation of Photosystem II D1 protein that empower efficient phenotypes of Chlamydomonas Reinhardtii under extreme environment in space

USDA-ARS?s Scientific Manuscript database

Oxygenic photosynthesis involves capture and conversion of light energy into chemical energy, a process fundamental to life including plant productivity on Earth. Photosynthetic electron transport is catalyzed by two photochemical reaction centres in series, photosystem II (PS II) and photosytem I (...

3D Space Radiation Transport in a Shielded ICRU Tissue Sphere

NASA Technical Reports Server (NTRS)

Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

2014-01-01

A computationally efficient 3DHZETRN code capable of simulating High Charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation was recently developed for a simple homogeneous shield object. Monte Carlo benchmarks were used to verify the methodology in slab and spherical geometry, and the 3D corrections were shown to provide significant improvement over the straight-ahead approximation in some cases. In the present report, the new algorithms with well-defined convergence criteria are extended to inhomogeneous media within a shielded tissue slab and a shielded tissue sphere and tested against Monte Carlo simulation to verify the solution methods. The 3D corrections are again found to more accurately describe the neutron and light ion fluence spectra as compared to the straight-ahead approximation. These computationally efficient methods provide a basis for software capable of space shield analysis and optimization.

Research and technology at Kennedy Space Center

NASA Technical Reports Server (NTRS)

1989-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, Kennedy Space Center is placing increasing emphasis on the Center's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of current mission, the technical tools are developed needed to execute Center's mission relative to future programs. The Engineering Development Directorate encompasses most of the laboratories and other Center resources that are key elements of research and technology program implementation and is responsible for implementation of the majority of the projects in this Kennedy Space Center 1989 Annual Report.

Computationally guided discovery of thermoelectric materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorai, Prashun; Stevanović, Vladan; Toberer, Eric S.

The potential for advances in thermoelectric materials, and thus solid-state refrigeration and power generation, is immense. Progress so far has been limited by both the breadth and diversity of the chemical space and the serial nature of experimental work. In this Review, we discuss how recent computational advances are revolutionizing our ability to predict electron and phonon transport and scattering, as well as materials dopability, and we examine efficient approaches to calculating critical transport properties across large chemical spaces. When coupled with experimental feedback, these high-throughput approaches can stimulate the discovery of new classes of thermoelectric materials. Within smaller materialsmore » subsets, computations can guide the optimal chemical and structural tailoring to enhance materials performance and provide insight into the underlying transport physics. Beyond perfect materials, computations can be used for the rational design of structural and chemical modifications (such as defects, interfaces, dopants and alloys) to provide additional control on transport properties to optimize performance. Through computational predictions for both materials searches and design, a new paradigm in thermoelectric materials discovery is emerging.« less

Lunar transportation system

NASA Technical Reports Server (NTRS)

1993-01-01

The University Space Research Association (USRA) requested the University of Minnesota Spacecraft Design Team to design a lunar transportation infrastructure. This task was a year long design effort culminating in a complete conceptual design and presentation at Johnson Space Center. The mission objective of the design group was to design a system of vehicles to bring a habitation module, cargo, and crew to the lunar surface from LEO and return either or both crew and cargo safely to LEO while emphasizing component commonality, reusability, and cost effectiveness. During the course of the design, the lunar transportation system (LTS) has taken on many forms. The final design of the system is composed of two vehicles, a lunar transfer vehicle (LTV) and a lunar excursion vehicle (LEV). The LTV serves as an efficient orbital transfer vehicle between the earth and the moon while the LEV carries crew and cargo to the lunar surface. Presented in the report are the mission analysis, systems layout, orbital mechanics, propulsion systems, structural and thermal analysis, and crew systems, avionics, and power systems for this lunar transportation concept.

Lunar transportation system

NASA Astrophysics Data System (ADS)

1993-07-01

The University Space Research Association (USRA) requested the University of Minnesota Spacecraft Design Team to design a lunar transportation infrastructure. This task was a year long design effort culminating in a complete conceptual design and presentation at Johnson Space Center. The mission objective of the design group was to design a system of vehicles to bring a habitation module, cargo, and crew to the lunar surface from LEO and return either or both crew and cargo safely to LEO while emphasizing component commonality, reusability, and cost effectiveness. During the course of the design, the lunar transportation system (LTS) has taken on many forms. The final design of the system is composed of two vehicles, a lunar transfer vehicle (LTV) and a lunar excursion vehicle (LEV). The LTV serves as an efficient orbital transfer vehicle between the earth and the moon while the LEV carries crew and cargo to the lunar surface. Presented in the report are the mission analysis, systems layout, orbital mechanics, propulsion systems, structural and thermal analysis, and crew systems, avionics, and power systems for this lunar transportation concept.

Computationally guided discovery of thermoelectric materials

DOE PAGES

Gorai, Prashun; Stevanović, Vladan; Toberer, Eric S.

2017-08-22

The potential for advances in thermoelectric materials, and thus solid-state refrigeration and power generation, is immense. Progress so far has been limited by both the breadth and diversity of the chemical space and the serial nature of experimental work. In this Review, we discuss how recent computational advances are revolutionizing our ability to predict electron and phonon transport and scattering, as well as materials dopability, and we examine efficient approaches to calculating critical transport properties across large chemical spaces. When coupled with experimental feedback, these high-throughput approaches can stimulate the discovery of new classes of thermoelectric materials. Within smaller materialsmore » subsets, computations can guide the optimal chemical and structural tailoring to enhance materials performance and provide insight into the underlying transport physics. Beyond perfect materials, computations can be used for the rational design of structural and chemical modifications (such as defects, interfaces, dopants and alloys) to provide additional control on transport properties to optimize performance. Through computational predictions for both materials searches and design, a new paradigm in thermoelectric materials discovery is emerging.« less

The Liquid Droplet Radiator - an Ultralightweight Heat Rejection System for Efficient Energy Conversion in Space

NASA Technical Reports Server (NTRS)

Mattick, A. T.; Hertzberg, A.

1984-01-01

A heat rejection system for space is described which uses a recirculating free stream of liquid droplets in place of a solid surface to radiate waste heat. By using sufficiently small droplets ( 100 micron diameter) of low vapor pressure liquids the radiating droplet sheet can be made many times lighter than the lightest solid surface radiators (heat pipes). The liquid droplet radiator (LDR) is less vulnerable to damage by micrometeoroids than solid surface radiators, and may be transported into space far more efficiently. Analyses are presented of LDR applications in thermal and photovoltaic energy conversion which indicate that fluid handling components (droplet generator, droplet collector, heat exchanger, and pump) may comprise most of the radiator system mass. Even the unoptimized models employed yield LDR system masses less than heat pipe radiator system masses, and significant improvement is expected using design approaches that incorporate fluid handling components more efficiently. Technical problems (e.g., spacecraft contamination and electrostatic deflection of droplets) unique to this method of heat rejectioon are discussed and solutions are suggested.

The liquid droplet radiator - An ultralightweight heat rejection system for efficient energy conversion in space

NASA Technical Reports Server (NTRS)

Mattick, A. T.; Hertzberg, A.

1981-01-01

A heat rejection system for space is described which uses a recirculating free stream of liquid droplets in place of a solid surface to radiate waste heat. By using sufficiently small droplets (less than about 100 micron diameter) of low vapor pressure liquids (tin, tin-lead-bismuth eutectics, vacuum oils) the radiating droplet sheet can be made many times lighter than the lightest solid surface radiators (heat pipes). The liquid droplet radiator (LDR) is less vulnerable to damage by micrometeoroids than solid surface radiators, and may be transported into space far more efficiently. Analyses are presented of LDR applications in thermal and photovoltaic energy conversion which indicate that fluid handling components (droplet generator, droplet collector, heat exchanger, and pump) may comprise most of the radiator system mass. Even the unoptimized models employed yield LDR system masses less than heat pipe radiator system masses, and significant improvement is expected using design approaches that incorporate fluid handling components more efficiently. Technical problems (e.g., spacecraft contamination and electrostatic deflection of droplets) unique to this method of heat rejection are discussed and solutions are suggested.

The PHITS code for space applications: status and recent developments

NASA Astrophysics Data System (ADS)

Sihver, Lembit; Ploc, Ondrej; Sato, Tatsuhiko; Niita, Koji; Hashimoto, Shintaro; El-Jaby, Samy

Since COSPAR 2012, the Particle and Heavy Ion Transport code System, PHITS, has been upgraded and released to the public [1]. The code has been improved and so has the contents of its package, such as the attached data libraries. In the new version, the intra-nuclear cascade models INCL4.6 and INC-ELF have been implemented as well as the Kurotama model for the total reaction cross sections. The accuracies of the new reaction models for transporting the galactic cosmic-rays were investigated by comparing with experimental data. The incorporation of these models has improved the capabilities of PHITS to perform particle transport simulations for different space applications. A methodology for assessing the pre-mission exposure of space crew aboard the ISS has been developed in terms of an effective dose equivalent [2]. PHITS was used to calculate the particle transport of the GCR and trapped radiation through the hull of the ISS. By using the predicted spectra, and fluence-to-dose conversion factors, the semi-empirical ISSCREM [3,4,5] code was then scaled to predict the effective dose equivalent. This methodology provides an opportunity for pre-flight predictions of the effective dose equivalent, which can be compared to post-flight estimates, and therefore offers a means to assess the impact of radiation exposure on ISS flight crew. We have also simulated [6] the protective curtain experiment, which was performed to test the efficiency of water-soaked hygienic tissue wipes and towels as a simple and cost-effective additional spacecraft shielding. The dose from the trapped particles and low energetic GCR, was significantly reduced, which shows that the protective curtains are efficient when they are applied on spacecraft at LEO. The results of these benchmark calculations, as well as the mentioned applications of PHITS to space dosimetry, will be presented. [1] T. Sato et al. J. Nucl. Sci. Technol. 50, 913-923 (2013). [2] S. El-Jaby, et al. Adv. Space Res. doi: http://dx.doi.org/10.1016/j.asr.2013.12.022 (2013). [3] S. El-Jaby, et al. Adv. Space Res. doi: http://dx.doi.org/10.1016/j.asr.2013.10.006 (2013). [4] S. El-Jaby, et al. In proc. to the IEEE Aerospace Conference, Big Sky, MN, USA (2013). [5] S. El-Jaby, PhD Thesis, Royal Military College of Canada (2012). [6] O. Ploc, et al., Adv. Space Res. 52, 1911-1918 (2013).

Application of Local Discretization Methods in the NASA Finite-Volume General Circulation Model

NASA Technical Reports Server (NTRS)

Yeh, Kao-San; Lin, Shian-Jiann; Rood, Richard B.

2002-01-01

We present the basic ideas of the dynamics system of the finite-volume General Circulation Model developed at NASA Goddard Space Flight Center for climate simulations and other applications in meteorology. The dynamics of this model is designed with emphases on conservative and monotonic transport, where the property of Lagrangian conservation is used to maintain the physical consistency of the computational fluid for long-term simulations. As the model benefits from the noise-free solutions of monotonic finite-volume transport schemes, the property of Lagrangian conservation also partly compensates the accuracy of transport for the diffusion effects due to the treatment of monotonicity. By faithfully maintaining the fundamental laws of physics during the computation, this model is able to achieve sufficient accuracy for the global consistency of climate processes. Because the computing algorithms are based on local memory, this model has the advantage of efficiency in parallel computation with distributed memory. Further research is yet desirable to reduce the diffusion effects of monotonic transport for better accuracy, and to mitigate the limitation due to fast-moving gravity waves for better efficiency.

An abstract approach to evaporation models in rarefied gas dynamics

NASA Astrophysics Data System (ADS)

Greenberg, W.; van der Mee, C. V. M.

1984-03-01

Strong evaporation models involving 1D stationary problems with linear self-adjoint collision operators and solutions in abstract Hilbert spaces are investigated analytically. An efficient algorithm for locating the transition from existence to nonexistence of solutions is developed and applied to the 1D and 3D BGK model equations and the 3D BGK model in moment form, demonstrating the nonexistence of stationary evaporation states with supersonic drift velocities. Applications to similar models in electron and phonon transport, radiative transfer, and neutron transport are suggested.

Space-charge limited photocurrent.

PubMed

Mihailetchi, V D; Wildeman, J; Blom, P W M

2005-04-01

In 1971 Goodman and Rose predicted the occurrence of a fundamental electrostatic limit for the photocurrent in semiconductors at high light intensities. Blends of conjugated polymers and fullerenes are an ideal model system to observe this space-charge limit experimentally, since they combine an unbalanced charge transport, long lifetimes, high charge carrier generation efficiencies, and low mobility of the slowest charge carrier. The experimental photocurrents reveal all the characteristics of a space-charge limited photocurrent: a one-half power dependence on voltage, a three-quarter power dependence on light intensity, and a one-half power scaling of the voltage at which the photocurrent switches into full saturation with light intensity.

Research and technology

NASA Technical Reports Server (NTRS)

1988-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery and operational support of Space Transportation System elements and payloads, Kennedy Space Center is placing emphasis on its research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of our current mission, we are developing the technological tools needed to execute the Center's mission relative to future programs. The Engineering Development Directorate encompasses most of the laboratories and other Center resources that are key elements of research and technology program implementation, and is responsible for implementation of the majority of the projects in this Kennedy Space Center 1988 Annual Report.

Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Production, Storage, and Transport. Part 3

NASA Technical Reports Server (NTRS)

Anderson, Tim; Balaban, Canan

2008-01-01

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Hydrogen storage and in-space hydrogen transport research focused on developing and verifying design concepts for efficient, safe, lightweight liquid hydrogen cryogenic storage systems. Research into hydrogen production had a specific goal of further advancing proton conducting membrane technology in the laboratory at a larger scale. System and process trade studies evaluated the proton conducting membrane technology, specifically, scale-up issues.

Feasibility Study of Space Based Solar Power to Tethered Aerostat Systems

NASA Technical Reports Server (NTRS)

Blank, Stephen J.; Leete, Stephen J.; Jaffe, Paul

2013-01-01

The feasibility of two-stage Space-Based Solar Power to Tethered Aerostat to Earth (SSP-TA) system architectures that offer significant advantages over conventional single stage space-to-earth architectures is being studied. There have been many proposals for the transmission of solar power collected in space to the surface of the earth so that solar energy could provide a major part of the electric power requirements on earth. There are, however, serious difficulties in implementing the single stage space-based solar power systems that have been previously studied. These difficulties arise due to: i) the cost of transporting the components needed for the extremely large microwave transmit beaming aperture into space orbit, ii) the even larger collection apertures required on earth, iii) the potential radiation hazard to personnel and equipment on earth, and iv) a lack of flexibility in location of the collection station on the earth. Two candidate system architectures are described here to overcome these difficulties. In both cases a two-stage space to tethered aerostat to earth transmission system (SSP-TA) is proposed. The use of high altitude tethered aerostats (or powered airships) avoids the effects of attenuation of EM energy propagating through the earth s lower atmosphere. This allows the use of beaming frequencies to be chosen from the range of high millimeter (THz) to near-infra-red (NIR) to the visible. This has the potential for: i) greatly reduced transportation costs to space, ii) much smaller receiver collection apertures and ground stations, iii) elimination of the potential radiation hazard to personnel and equipment on earth, and iv) ease in transportation and flexibility in location of the collection station on the earth. A preliminary comparison of system performance and efficiencies is presented.

75 FR 23841 - Commercial Space Transportation Grant Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-04

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Grant... for the Commercial Space Transportation Grant Program. SUMMARY: The FAA's Office of Commercial Space Transportation (AST) requests grant proposals pursuant to its newly funded Commercial Space Transportation Grant...

Preliminary design and cost of a 1-megawatt solar-pumped iodide laser space-to-space transmission station

NASA Technical Reports Server (NTRS)

Deyoung, R. J.; Walker, G. H.; Williams, M. D.; Schuster, G. L.; Conway, E. J.

1987-01-01

A preliminary conceptual design of a space-based solar pumped iodide laser emitting 1 megawatt of laser power for space-to-space power transmission is described. A near parabolic solar collector focuses sunlight onto the t-C4F9I (perfluoro-t butyl iodide) lasant within a transverse flow optical cavity. Using waste heat, a thermal system was designed to supply compressor and auxiliary power. System components were designed with weight and cost estimates assigned. Although cost is very approximate, the cost comparison of individual system components leads to valuable insights for future research. In particular, it was found that laser efficiency was not a dominant cost or weight factor, the dominant factor being the laser cavity and laser transmission optics. The manufacturing cost was approx. two thirds of the total cost with transportation to orbit the remainder. The flowing nonrenewable lasant comprised 20% of the total life cycle cost of the system and thus was not a major cost factor. The station mass was 92,000 kg without lasant, requiring approx. four shuttle flights to low Earth orbit where an orbital transfer vehicle will transport it to the final altitude of 6378 km.

Modular System to Enable Extravehicular Activity

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2012-01-01

The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space systems (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower Earth orbit (LEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular EVA system that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs, and to define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Space Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option was included to make use of the developing suit port technologies.

High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

NASA Technical Reports Server (NTRS)

Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

1991-01-01

The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

C70/C70:pentacene/pentacene organic heterojunction as the connecting layer for high performance tandem organic light-emitting diodes: Mechanism investigation of electron injection and transport

NASA Astrophysics Data System (ADS)

Guo, Qingxun; Yang, Dezhi; Chen, Jiangshan; Qiao, Xianfeng; Ahamad, Tansir; Alshehri, Saad M.; Ma, Dongge

2017-03-01

A high performance tandem organic light-emitting diode (OLED) is realized by employing a C70/C70:pentacene/pentacene organic heterojunction as the efficient charge generation layer (CGL). Not only more than two time enhancement of external quantum efficiency but also significant improvement in both power efficiency and lifetime are well achieved. The mechanism investigations find that the electron injection from the CGL to the adjacent electron transport layer (ETL) in tandem devices is injection rate-limited due to the high interface energy barrier between the CGL and the ETL. By the capacitance-frequency (C-F) and low temperature current density-voltage (J-V) characteristic analysis, we confirm that the electron transport is a space-charge-limited current process with exponential trap distribution. These traps are localized states below the lowest unoccupied molecular orbital edge inside the gap and would be filled with the upward shift of the Fermi level during the n-doping process. Furthermore, both the trap density (Ht) and the activation energy (Ea) could be carefully worked out through low temperature J-V measurements, which is very important for developing high performance tandem OLEDs.

In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

NASA Technical Reports Server (NTRS)

Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

1990-01-01

Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

Hybrid Power Management (HPM) Program Resulted in Several New Applications

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2003-01-01

Hybrid Power Management (HPM) is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors, fuel cells, and photovoltaics. HPM has extremely wide potential with applications from nanowatts to megawatts. Applications include power generation, transportation systems, biotechnology systems, and space power systems. HPM has the potential to significantly alleviate global energy concerns, improve the environment, and stimulate the economy.

Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections: A Space- Physics Application

NASA Technical Reports Server (NTRS)

Barghouty, A. F.

2014-01-01

Accurate estimates of electroncapture cross sections at energies relevant to the modeling of the transport, acceleration, and interaction of energetic neutral atoms (ENA) in space (approximately few MeV per nucleon) and especially for multi-electron ions must rely on detailed, but computationally expensive, quantum-mechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts for apace applications, we shall briefly present this approach along with sample applications and report on current progress.

Space Commercial Opportunities for Fluid Physics and Transport Phenomena Applications

NASA Technical Reports Server (NTRS)

Gavert, R.

2000-01-01

Microgravity research at NASA has been an undertaking that has included both science and commercial approaches since the late 80s and early 90s. The Fluid Physics and Transport Phenomena community has been developed, through NASA's science grants, into a valuable base of expertise in microgravity science. This was achieved through both ground and flight scientific research. Commercial microgravity research has been primarily promoted thorough NASA sponsored Centers for Space Commercialization which develop cost sharing partnerships with industry. As an example, the Center for Advanced Microgravity Materials Processing (CAMMP)at Northeastern University has been working with cost sharing industry partners in developing Zeolites and zeo-type materials as an efficient storage medium for hydrogen fuel. Greater commercial interest is emerging. The U.S. Congress has passed the Commercial Space Act of 1998 to encourage the development of a commercial space industry in the United States. The Act has provisions for the commercialization of the International Space Station (ISS). Increased efforts have been made by NASA to enable industrial ventures on-board the ISS. A Web site has been established at http://commercial/nasa/gov which includes two important special announcements. One is an open request for entrepreneurial offers related to the commercial development and use of the ISS. The second is a price structure and schedule for U.S. resources and accommodations. The purpose of the presentation is to make the Fluid Physics and Transport Phenomena community, which understands the importance of microgravity experimentation, aware of important aspects of ISS commercial development. It is a desire that this awareness will be translated into a recognition of Fluid Physics and Transport Phenomena application opportunities coordinated through the broad contacts of this community with industry.

Shielding from space radiations

NASA Technical Reports Server (NTRS)

Chang, C. Ken; Badavi, Forooz F.; Tripathi, Ram K.

1993-01-01

This Progress Report covering the period of December 1, 1992 to June 1, 1993 presents the development of an analytical solution to the heavy ion transport equation in terms of Green's function formalism. The mathematical development results are recasted into a highly efficient computer code for space applications. The efficiency of this algorithm is accomplished by a nonperturbative technique of extending the Green's function over the solution domain. The code may also be applied to accelerator boundary conditions to allow code validation in laboratory experiments. Results from the isotopic version of the code with 59 isotopes present for a single layer target material, for the case of an iron beam projectile at 600 MeV/nucleon in water is presented. A listing of the single layer isotopic version of the code is included.

Path Toward a Unified Geometry for Radiation Transport

NASA Astrophysics Data System (ADS)

Lee, Kerry

The Direct Accelerated Geometry for Radiation Analysis and Design (DAGRAD) element of the RadWorks Project under Advanced Exploration Systems (AES) within the Space Technology Mission Directorate (STMD) of NASA will enable new designs and concepts of operation for radiation risk assessment, mitigation and protection. This element is designed to produce a solution that will allow NASA to calculate the transport of space radiation through complex CAD models using the state-of-the-art analytic and Monte Carlo radiation transport codes. Due to the inherent hazard of astronaut and spacecraft exposure to ionizing radiation in low-Earth orbit (LEO) or in deep space, risk analyses must be performed for all crew vehicles and habitats. Incorporating these analyses into the design process can minimize the mass needed solely for radiation protection. Transport of the radiation fields as they pass through shielding and body materials can be simulated using Monte Carlo techniques or described by the Boltzmann equation, which is obtained by balancing changes in particle fluxes as they traverse a small volume of material with the gains and losses caused by atomic and nuclear collisions. Deterministic codes that solve the Boltzmann transport equation, such as HZETRN (high charge and energy transport code developed by NASA LaRC), are generally computationally faster than Monte Carlo codes such as FLUKA, GEANT4, MCNP(X) or PHITS; however, they are currently limited to transport in one dimension, which poorly represents the secondary light ion and neutron radiation fields. NASA currently uses HZETRN space radiation transport software, both because it is computationally efficient and because proven methods have been developed for using this software to analyze complex geometries. Although Monte Carlo codes describe the relevant physics in a fully three-dimensional manner, their computational costs have thus far prevented their widespread use for analysis of complex CAD models, leading to the creation and maintenance of toolkit specific simplistic geometry models. The work presented here builds on the Direct Accelerated Geometry Monte Carlo (DAGMC) toolkit developed for use with the Monte Carlo N-Particle (MCNP) transport code. The work-flow for doing radiation transport on CAD models using MCNP and FLUKA has been demonstrated and the results of analyses on realistic spacecraft/habitats will be presented. Future work is planned that will further automate this process and enable the use of multiple radiation transport codes on identical geometry models imported from CAD. This effort will enhance the modeling tools used by NASA to accurately evaluate the astronaut space radiation risk and accurately determine the protection provided by as-designed exploration mission vehicles and habitats.

Project RAMA: Reconstructing Asteroids Into Mechanical Automata

NASA Technical Reports Server (NTRS)

Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

2017-01-01

Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be captured and transported using Earth-launched propulsion technology. Project RAMA is not forced into this constraint. The mission concept studied involved transporting a much larger approximately 50-meter asteroid to cislunar space. Demonstration of transport of a 50-meter-class asteroid has several ground-breaking advantages. First, the returned material is of an industrial, rather than just scientific, quantity (greater than 10,000 tonnes versus approximately10s of tonnes). Second, the "useless" material in the asteroid is gathered and expended as part of the asteroid's propulsion system, allowing the returned asteroid to be considerably "purer" than a conventional asteroid retrieval mission. Third, the infrastructure used to convert and return the asteroid is reusable, and capable of continually returning asteroids to cislunar space.

Chemical Continuous Time Random Walks

NASA Astrophysics Data System (ADS)

Aquino, T.; Dentz, M.

2017-12-01

Traditional methods for modeling solute transport through heterogeneous media employ Eulerian schemes to solve for solute concentration. More recently, Lagrangian methods have removed the need for spatial discretization through the use of Monte Carlo implementations of Langevin equations for solute particle motions. While there have been recent advances in modeling chemically reactive transport with recourse to Lagrangian methods, these remain less developed than their Eulerian counterparts, and many open problems such as efficient convergence and reconstruction of the concentration field remain. We explore a different avenue and consider the question: In heterogeneous chemically reactive systems, is it possible to describe the evolution of macroscopic reactant concentrations without explicitly resolving the spatial transport? Traditional Kinetic Monte Carlo methods, such as the Gillespie algorithm, model chemical reactions as random walks in particle number space, without the introduction of spatial coordinates. The inter-reaction times are exponentially distributed under the assumption that the system is well mixed. In real systems, transport limitations lead to incomplete mixing and decreased reaction efficiency. We introduce an arbitrary inter-reaction time distribution, which may account for the impact of incomplete mixing. This process defines an inhomogeneous continuous time random walk in particle number space, from which we derive a generalized chemical Master equation and formulate a generalized Gillespie algorithm. We then determine the modified chemical rate laws for different inter-reaction time distributions. We trace Michaelis-Menten-type kinetics back to finite-mean delay times, and predict time-nonlocal macroscopic reaction kinetics as a consequence of broadly distributed delays. Non-Markovian kinetics exhibit weak ergodicity breaking and show key features of reactions under local non-equilibrium.

Research and technology 1987 annual report of the Kennedy Space Center

NASA Technical Reports Server (NTRS)

1987-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, Kennedy Space Center is placing increasing emphasis on the Center's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of our current mission, we are developing the technological tools needed to execute the Center's mission relative to future programs. The Engineering Development Directorate encompasses most of the laboratories and other Center resources that are key elements of research and technology program implementation, and is responsible for implementation of the majority of the projects of this Kennedy Space Center 1987 Annual Report.

On-Line Tool for the Assessment of Radiation in Space - Deep Space Mission Enhancements

NASA Technical Reports Server (NTRS)

Sandridge, Chris a.; Blattnig, Steve R.; Norman, Ryan B.; Slaba, Tony C.; Walker, Steve A.; Spangler, Jan L.

2011-01-01

The On-Line Tool for the Assessment of Radiation in Space (OLTARIS, https://oltaris.nasa.gov) is a web-based set of tools and models that allows engineers and scientists to assess the effects of space radiation on spacecraft, habitats, rovers, and spacesuits. The site is intended to be a design tool for those studying the effects of space radiation for current and future missions as well as a research tool for those developing advanced material and shielding concepts. The tools and models are built around the HZETRN radiation transport code and are primarily focused on human- and electronic-related responses. The focus of this paper is to highlight new capabilities that have been added to support deep space (outside Low Earth Orbit) missions. Specifically, the electron, proton, and heavy ion design environments for the Europa mission have been incorporated along with an efficient coupled electron-photon transport capability to enable the analysis of complicated geometries and slabs exposed to these environments. In addition, a neutron albedo lunar surface environment was also added, that will be of value for the analysis of surface habitats. These updates will be discussed in terms of their implementation and on how OLTARIS can be used by instrument vendors, mission designers, and researchers to analyze their specific requirements.12

Particle transport in low-energy ventilation systems. Part 1: theory of steady states.

PubMed

Bolster, D T; Linden, P F

2009-04-01

Many modern low-energy ventilation schemes, such as displacement or natural ventilation, take advantage of temperature stratification in a space, extracting the warmest air from the top of the room. The adoption of these energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. In this work we study the steady state transport of particulate contaminants in a displacement-ventilated space. Representing heat sources as ideal sources of buoyancy, analytical models are developed that allow us to compare the average efficiency of contaminant removal between traditional and modern low-energy systems. We found that on average traditional and low-energy systems are similar in overall pollutant removal efficiency, although quite different vertical distributions of contaminant can exist, thus affecting individual exposure. While the main focus of this work is on particles where the dominant mode of deposition is by gravitational settling, we also discuss additional deposition mechanisms and show that the qualitative observations we make carry over to cases where such mechanisms must be included. We illustrate that while average concentration of particles for traditional mixing systems and low energy displacement systems are similar, local concentrations can vary significantly with displacement systems. Depending on the source of the particles this can be better or worse in terms of occupant exposure and engineers should take due diligence accordingly when designing ventilation systems.

Proton exchange membrane fuel cells for space and electric vehicle applications: From basic research to technology development

NASA Technical Reports Server (NTRS)

Srinivasan, Supramaniam; Mukerjee, Sanjeev; Parthasarathy, A.; CesarFerreira, A.; Wakizoe, Masanobu; Rho, Yong Woo; Kim, Junbom; Mosdale, Renaut A.; Paetzold, Ronald F.; Lee, James

1994-01-01

The proton exchange membrane fuel cell (PEMFC) is one of the most promising electrochemical power sources for space and electric vehicle applications. The wide spectrum of R&D activities on PEMFC's, carried out in our Center from 1988 to date, is as follows (1) Electrode Kinetic and Electrocatalysis of Oxygen Reduction; (2) Optimization of Structures of Electrodes and of Membrane and Electrode Assemblies; (3) Selection and Evaluation of Advanced Proton Conducting Membranes and of Operating Conditions to Attain High Energy Efficiency; (4) Modeling Analysis of Fuel Cell Performance and of Thermal and Water Management; and (5) Engineering Design and Development of Multicell Stacks. The accomplishments on these tasks may be summarized as follows: (1) A microelectrode technique was developed to determine the electrode kinetic parameters for the fuel cell reactions and mass transport parameters for the H2 and O2 reactants in the proton conducting membrane. (2) High energy efficiencies and high power densities were demonstrated in PEMFCs with low platinum loading electrodes (0.4 mg/cm(exp 2) or less), advanced membranes and optimized structures of membrane and electrode assemblies, as well as operating conditions. (3) The modeling analyses revealed methods to minimize mass transport limitations, particularly with air as the cathodic reactant; and for efficient thermal and water management. (4) Work is in progress to develop multi-kilowatt stacks with the electrodes containing low platinum loadings.

Phase-space finite elements in a least-squares solution of the transport equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drumm, C.; Fan, W.; Pautz, S.

2013-07-01

The linear Boltzmann transport equation is solved using a least-squares finite element approximation in the space, angular and energy phase-space variables. The method is applied to both neutral particle transport and also to charged particle transport in the presence of an electric field, where the angular and energy derivative terms are handled with the energy/angular finite elements approximation, in a manner analogous to the way the spatial streaming term is handled. For multi-dimensional problems, a novel approach is used for the angular finite elements: mapping the surface of a unit sphere to a two-dimensional planar region and using a meshingmore » tool to generate a mesh. In this manner, much of the spatial finite-elements machinery can be easily adapted to handle the angular variable. The energy variable and the angular variable for one-dimensional problems make use of edge/beam elements, also building upon the spatial finite elements capabilities. The methods described here can make use of either continuous or discontinuous finite elements in space, angle and/or energy, with the use of continuous finite elements resulting in a smaller problem size and the use of discontinuous finite elements resulting in more accurate solutions for certain types of problems. The work described in this paper makes use of continuous finite elements, so that the resulting linear system is symmetric positive definite and can be solved with a highly efficient parallel preconditioned conjugate gradients algorithm. The phase-space finite elements capability has been built into the Sceptre code and applied to several test problems, including a simple one-dimensional problem with an analytic solution available, a two-dimensional problem with an isolated source term, showing how the method essentially eliminates ray effects encountered with discrete ordinates, and a simple one-dimensional charged-particle transport problem in the presence of an electric field. (authors)« less

Optimal technology investment strategies for a reusable launch vehicle

NASA Technical Reports Server (NTRS)

Moore, A. A.; Braun, R. D.; Powell, R. W.

1995-01-01

Within the present budgetary environment, developing the technology that leads to an operationally efficient space transportation system with the required performance is a challenge. The present research focuses on a methodology to determine high payoff technology investment strategies. Research has been conducted at Langley Research Center in which design codes for the conceptual analysis of space transportation systems have been integrated in a multidisciplinary design optimization approach. The current study integrates trajectory, propulsion, weights and sizing, and cost disciplines where the effect of technology maturation on the development cost of a single stage to orbit reusable launch vehicle is examined. Results show that the technology investment prior to full-scale development has a significant economic payoff. The design optimization process is used to determine strategic allocations of limited technology funding to maximize the economic payoff.

F--Ray: A new algorithm for efficient transport of ionizing radiation

NASA Astrophysics Data System (ADS)

Mao, Yi; Zhang, J.; Wandelt, B. D.; Shapiro, P. R.; Iliev, I. T.

2014-04-01

We present a new algorithm for the 3D transport of ionizing radiation, called F2-Ray (Fast Fourier Ray-tracing method). The transfer of ionizing radiation with long mean free path in diffuse intergalactic gas poses a special challenge to standard numerical methods which transport the radiation in position space. Standard methods usually trace each individual ray until it is fully absorbed by the intervening gas. If the mean free path is long, the computational cost and memory load are likely to be prohibitive. We have developed an algorithm that overcomes these limitations and is, therefore, significantly more efficient. The method calculates the transfer of radiation collectively, using the Fast Fourier Transform to convert radiation between position and Fourier spaces, so the computational cost will not increase with the number of ionizing sources. The method also automatically combines parallel rays with the same frequency at the same grid cell, thereby minimizing the memory requirement. The method is explicitly photon-conserving, i.e. the depletion of ionizing photons is guaranteed to equal the photoionizations they caused, and explicitly obeys the periodic boundary condition, i.e. the escape of ionizing photons from one side of a simulation volume is guaranteed to be compensated by emitting the same amount of photons into the volume through the opposite side. Together, these features make it possible to numerically simulate the transfer of ionizing photons more efficiently than previous methods. Since ionizing radiation such as the X-ray is responsible for heating the intergalactic gas when first stars and quasars form at high redshifts, our method can be applied to simulate thermal distribution, in addition to cosmic reionization, in three-dimensional inhomogeneous cosmological density field.

KSC-2012-1328

NASA Image and Video Library

2012-02-14

COCOA BEACH, Fla. -- Lee Pagel, the NASA Participant Evaluation Panel PEP deputy for the Commercial Crew Program CCP, talks to industry partners and stakeholders during a preproposal conference at the Courtyard Marriott in Cocoa Beach, Fla. The meeting focused on information related to NASA's release of the Commercial Crew Integrated Capability CCiCap Announcement for Proposals on Feb. 7. More than 50 people from 25 aerospace companies attended the conference to find out what the space agency would be looking for in terms of milestones, funding, schedules, strategies, safety cultures, business modules and eventual flight certification standards of integrated crew space transportation systems. The goal of the CCiCap is to develop an indigenous U.S. transportation system that can safely, affordably and routinely fly to low Earth orbit destinations, including the International Space Station. Proposals are due March 23 and NASA plans to award multiple Space Act Agreements, valued from $300 million to $500 million each, toward the development of fully integrated commercial crew transportation systems in the summer of 2012. For more information, visit www.nasa.gov/commercialcrew Photo credit: Kim Shiflett The Ground Systems Development and Operations Program is developing the necessary ground systems, infrastructure and operational approaches required to safely process, assemble, transport and launch the next generation of rockets and spacecraft in support of NASA’s exploration objectives. Future work also will replace the antiquated communications, power and vehicle access resources with modern efficient systems. Some of the utilities and systems slated for replacement have been used since the VAB opened in 1965. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Kim Shiflett

Development of Electronics for Low-Temperature Space Missions

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad; Dickman, John E.; Gerber, Scott S.; Overton, Eric

2001-01-01

Electronic systems that are capable of operating at cryogenic temperatures will be needed for many future NASA space missions, including deep space probes and spacecraft for planetary surface exploration. In addition to being able to survive the harsh deep space environment, low-temperature electronics would help improve circuit performance, increase system efficiency, and reduce payload development and launch costs. Terrestrial applications where components and systems must operate in low-temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation systems, and arctic exploration. An ongoing research and development project for the design, fabrication, and characterization of low-temperature electronics and supporting technologies at NASA Glenn Research Center focuses on efficient power systems capable of surviving in and exploiting the advantages of low-temperature environments. Supporting technologies include dielectric and insulating materials, semiconductor devices, passive power components, optoelectronic devices, and packaging and integration of the developed components into prototype flight hardware. An overview of the project is presented, including a description of the test facilities, a discussion of selected data from component testing, and a presentation of ongoing research activities being performed in collaboration with various organizations.

Electronic Components and Systems for Cryogenic Space Applications

NASA Technical Reports Server (NTRS)

Patterson, R. L.; Hammoud, A.; Dickman, J. E.; Gerber, S.; Elbuluk, M. E.; Overton, E.

2001-01-01

Electronic components and systems capable of operation at cryogenic temperatures are anticipated in many future NASA space missions such as deep space probes and planetary surface exploration. For example, an unheated interplanetary probe launched to explore the rings of Saturn would reach an average temperature near Saturn of about - 183 C. In addition to surviving the deep space harsh environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing payload development and launch costs. Terrestrial applications where components and systems must operate in low temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation system, and arctic exploration. An on-going research and development program at the NASA Glenn Research Center focuses on the development of reliable electronic devices and efficient power systems capable of surviving in low temperature environments. An overview of the program will be presented in this paper. A description of the low temperature test facilities along with selected data obtained from in-house component testing will also be discussed. Ongoing research activities that are being performed in collaboration with various organizations will also be presented.

Bunch compression efficiency of the femtosecond electron source at Chiang Mai University

NASA Astrophysics Data System (ADS)

Thongbai, C.; Kusoljariyakul, K.; Saisut, J.

2011-07-01

A femtosecond electron source has been developed at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand. Ultra-short electron bunches can be produced with a bunch compression system consisting of a thermionic cathode RF-gun, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. To obtain effective bunch compression, it is crucial to provide a proper longitudinal phase-space distribution at the gun exit matched to the subsequent beam transport system. Via beam dynamics calculations and experiments, we investigate the bunch compression efficiency for various RF-gun fields. The particle distribution at the RF-gun exit will be tracked numerically through the alpha-magnet and beam transport. Details of the study and results leading to an optimum condition for our system will be presented.

77 FR 71474 - Commercial Space Transportation Advisory Committee-Charter Renewal

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-30

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Transportation (DOT). ACTION: Announcement of Charter Renewal of the Commercial Space Transportation Advisory... space transportation industry. This charter renewal will take effect on November 16, 2012, and will...

14 CFR 401.1 - The Office of Commercial Space Transportation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false The Office of Commercial Space Transportation. 401.1 Section 401.1 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL ORGANIZATION AND DEFINITIONS § 401.1 The Office of Commercial Space Transportation. The Office of...

HyPlane for Space Tourism and Business Transportation

NASA Astrophysics Data System (ADS)

Savino, R.

In the present work a preliminary study on a small hypersonic airplane for a long duration space tourism mission is presented. It is also consistent with a point-to-point medium range (5000-6000 km) hypersonic trip, in the frame of the "urgent business travel" market segment. The main ideas is to transfer technological solutions developed for aeronautical and space atmospheric re-entry systems to the design of such a hypersonic airplane. A winged vehicle characterized by high aerodynamic efficiency and able to manoeuvre along the flight path, in all aerodynamic regimes encountered, is taken into consideration. Rocket-Based Combined Cycle and Turbine-Based Combined Cycle engines are investigated to ensure higher performances in terms of flight duration and range. Different flight-paths are also considered, including sub-orbital parabolic trajectories and steady state hypersonic cruise. The former, in particular, takes advantage of the high aerodynamic efficiency during the unpowered phase, in combination with a periodic engine actuation, to guarantee a long duration oscillating flight path. These trajectories offer Space tourists the opportunity of extended missions, characterized by repeated periods of low-gravity at altitudes high enough to ensure a wide view of the Earth from Space.

Contaminants in ventilated filling boxes

NASA Astrophysics Data System (ADS)

Bolster, D. T.; Linden, P. F.

While energy efficiency is important, the adoption of energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. Many low-energy systems, such as displacement or natural ventilation, rely on temperature stratification within the interior environment, always extracting the warmest air from the top of the room. Understanding buoyancy-driven convection in a confined ventilated space is key to understanding the flow that develops with many of these modern low-energy ventilation schemes. In this work we study the transport of an initially uniformly distributed passive contaminant in a displacement-ventilated space. Representing a heat source as an ideal sourced of buoyancy, analytical and numerical models are developed that allow us to compare the average efficiency of contaminant removal between traditional mixing and modern low-energy systems. A set of small-scale analogue laboratory experiments was also conducted to further validate our analytical and numerical solutions.We find that on average traditional and low-energy ventilation methods are similar with regard to pollutant flushing efficiency. This is because the concentration being extracted from the system at any given time is approximately the same for both systems. However, very different vertical concentration gradients exist. For the low-energy system, a peak in contaminant concentration occurs at the temperature interface that is established within the space. This interface is typically designed to sit at some intermediate height in the space. Since this peak does not coincide with the extraction point, displacement ventilation does not offer the same benefits for pollutant flushing as it does for buoyancy removal.

Aerospace applications of atmospheric rendezvous.

NASA Technical Reports Server (NTRS)

Bird, J. D.; Schaezler, A. D.

1972-01-01

This paper studies the feasibility of the use of an atmospheric rendezvous concept to increase the efficiency and flexibility of space transportation systems. In this concept the second stage of a recoverable orbital launch vehicle or hypersonic transport would be built without wings, landing gear, or subsonic flight propulsion, and would be received in an atmospheric rendezvous by a carrier vehicle at the terminal point of flight for subsequent ferry to a landing site. Significant possibilities for weight improvement are shown and the attractiveness of a subsonic form of atmospheric rendezvous in either a towing or docking mode is illustrated.

Finite temperature dynamics of a Holstein polaron: The thermo-field dynamics approach

NASA Astrophysics Data System (ADS)

Chen, Lipeng; Zhao, Yang

2017-12-01

Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling. While for weak to moderate diagonal coupling temperature increases inhibit polaron mobility, it is found that off-diagonal coupling induces phonon-assisted transport that dominates at high temperatures. Results on the mean square displacements show that band-like transport features dominate the diagonal coupling cases, and there exists a crossover from band-like to hopping transport with increasing temperature when including off-diagonal coupling. As a proof of concept, our theory provides a unified treatment of coherent and incoherent transport in molecular crystals and is applicable to any temperature.

Role of Oxygen Functionalities in Graphene Oxide Architectural Laminate Subnanometer Spacing and Water Transport.

PubMed

Amadei, Carlo Alberto; Montessori, Andrea; Kadow, Julian P; Succi, Sauro; Vecitis, Chad D

2017-04-18

Active research in nanotechnology contemplates the use of nanomaterials for environmental engineering applications. However, a primary challenge is understanding the effects of nanomaterial properties on industrial device performance and translating unique nanoscale properties to the macroscale. One emerging example consists of graphene oxide (GO) membranes for separation processes. Thus, here we investigate how individual GO properties can impact GO membrane characteristics and water permeability. GO chemistry and morphology were controlled with easy-to-implement photoreduction and sonication techniques and were quantitatively correlated, offering a valuable tool for accelerating characterization. Chemical GO modification allows for fine control of GO oxidation state, allowing control of GO architectural laminate (GOAL) spacing and permeability. Water permeability was measured for eight GOALs characterized by different GOAL chemistry and morphology and indicates that GOAL nanochannel height dictates water transport. The experimental outputs were corroborated with mesoscale water transport simulations of relatively large domains (thousands of square nanometers) and indicate a no-slip Darcy-like behavior inside the GOAL nanochannels. The experimental and simulation evidence presented in this study helps create a clearer picture of water transport in GOAL and can be used to rationally design more effective and efficient GO membranes.

Space shuttle/food system study. Volume 2, Appendix G: Ground support system analysis. Appendix H: Galley functional details analysis

NASA Technical Reports Server (NTRS)

1974-01-01

The capabilities for preflight feeding of flight personnel and the supply and control of the space shuttle flight food system were investigated to determine ground support requirements; and the functional details of an onboard food system galley are shown in photographic mockups. The elements which were identified as necessary to the efficient accomplishment of ground support functions include the following: (1) administration; (2) dietetics; (3) analytical laboratories; (4) flight food warehouse; (5) stowage module assembly area; (6) launch site module storage area; (7) alert crew restaurant and disperse crew galleys; (8) ground food warehouse; (9) manufacturing facilities; (10) transport; and (11) computer support. Each element is discussed according to the design criteria of minimum cost, maximum flexibility, reliability, and efficiency consistent with space shuttle requirements. The galley mockup overview illustrates the initial operation configuration, food stowage locations, meal assembly and serving trays, meal preparation configuration, serving, trash management, and the logistics of handling and cleanup equipment.

Research and technology

NASA Technical Reports Server (NTRS)

1986-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, Kennedy Space Center is placing increasing emphasis on the Center's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of our current mission, we are developing the technological tools needed to execute the Center's mission relative to future programs. The Engineering Development Directorate encompasses most of the laboratories and other Center resources that are key elements of research and technology program implementation, and is responsible for implementation of the majority of the projects in this Kennedy Space Center 1986 Annual Report.

78 FR 1917 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-09

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation...: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to the... Group (BLWG) of the Commercial Space Transportation Advisory Committee (COMSTAC). DATES: The...

Research and technology

NASA Technical Reports Server (NTRS)

1985-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, Kennedy Space Center is placing increasing emphasis on the Center's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safe, more efficient, and more economical execution of our current mission, we are developing the technological tools needed to execute the Center's mission relative to Space Station and other future programs. The Engineering Development Directorate encompasses most of the laboratories and other Center resources that are key elements of research and technology program implementation and is responsible for implementation of the majority of the projects in this Kennedy Space Center 1985 Annual Report. The report contains brief descriptions of research and technology projects in major areas of Kennedy Space Center's disciplinary expertise.

Cryogenic Fluid Management Facility

NASA Technical Reports Server (NTRS)

Eberhardt, R. N.; Bailey, W. J.; Symons, E. P.; Kroeger, E. W.

1984-01-01

The Cryogenic Fluid Management Facility (CFMF) is a reusable test bed which is designed to be carried into space in the Shuttle cargo bay to investigate systems and technologies required to efficiently and effectively manage cryogens in space. The facility hardware is configured to provide low-g verification of fluid and thermal models of cryogenic storage, transfer concepts and processes. Significant design data and criteria for future subcritical cryogenic storage and transfer systems will be obtained. Future applications include space-based and ground-based orbit transfer vehicles (OTV), space station life support, attitude control, power and fuel depot supply, resupply tankers, external tank (ET) propellant scavenging, space-based weapon systems and space-based orbit maneuvering vehicles (OMV). This paper describes the facility and discusses the cryogenic fluid management technology to be investigated. A brief discussion of the integration issues involved in loading and transporting liquid hydrogen within the Shuttle cargo bay is also included.

76 FR 15039 - Commercial Space Transportation Grants Program

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2011-03-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... proposals for the Commercial Space Transportation Grant Program. SUMMARY: This notice solicits Fiscal Year (FY) 2011 grant proposals to continue the development of a Commercial Space Transportation...

75 FR 70347 - Commercial Space Transportation Advisory Committee; Renewal

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2010-11-17

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Regulations, notice is hereby given that the Commercial Space Transportation Advisory Committee (COMSTAC) has... matters concerning the U.S. commercial space transportation industry. The [[Page 70348

76 FR 41323 - Commercial Space Transportation Advisory Committee-Public Teleconference

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2011-07-13

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76 FR 4988 - Commercial Space Transportation Advisory Committee-Public Teleconference

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2011-01-27

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76 FR 621 - Commercial Space Transportation Advisory Committee-Public Teleconference

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2011-01-05

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation...: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section... given of a teleconference of the Commercial Space Transportation Advisory Committee (COMSTAC). The...

Multimodal transport and dispersion of organelles in narrow tubular cells

NASA Astrophysics Data System (ADS)

Mogre, Saurabh S.; Koslover, Elena F.

2018-04-01

Intracellular components explore the cytoplasm via active motor-driven transport in conjunction with passive diffusion. We model the motion of organelles in narrow tubular cells using analytical techniques and numerical simulations to study the efficiency of different transport modes in achieving various cellular objectives. Our model describes length and time scales over which each transport mode dominates organelle motion, along with various metrics to quantify exploration of intracellular space. For organelles that search for a specific target, we obtain the average capture time for given transport parameters and show that diffusion and active motion contribute to target capture in the biologically relevant regime. Because many organelles have been found to tether to microtubules when not engaged in active motion, we study the interplay between immobilization due to tethering and increased probability of active transport. We derive parameter-dependent conditions under which tethering enhances long-range transport and improves the target capture time. These results shed light on the optimization of intracellular transport machinery and provide experimentally testable predictions for the effects of transport regulation mechanisms such as tethering.

76 FR 4412 - Commercial Space Transportation Advisory Committee-Closed Session

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2011-01-25

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a... Commercial Space Transportation Advisory Committee (COMSTAC). The special closed session will be an...

75 FR 71791 - Commercial Space Transportation Advisory Committee-Public Teleconference

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2010-11-24

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation...: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section... given of a teleconference of the Space Transportation Operations Working Group (STOWG) of the Commercial...

78 FR 37648 - Space Transportation Infrastructure Matching (STIM) Grants Program

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2013-06-21

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Space Transportation Infrastructure...-availability of Space Transportation Infrastructure Matching Grants in FY 2013. SUMMARY: The Office of Commercial Space Transportation (AST) will not solicit or award grants under the STIM program this fiscal...

78 FR 70093 - Commercial Space Transportation Advisory Committee-Closed Session

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2013-11-22

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a...), notice is hereby given of a special closed session of the Commercial Space Transportation Advisory...

77 FR 52108 - Commercial Space Transportation Advisory Committee; Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-28

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open Meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

78 FR 18416 - Commercial Space Transportation Advisory Committee; Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open Meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

75 FR 16901 - Commercial Space Transportation Advisory Committee-Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open meeting. SUMMARY: Pursuant to section 10(a)(2) of the... of the Commercial Space Transportation Advisory Committee (COMSTAC). The meetings will take place on...

76 FR 17474 - Commercial Space Transportation Advisory Committee-Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-29

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open Meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

75 FR 54002 - Commercial Space Transportation Advisory Committee-Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-02

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open Meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

78 FR 53496 - Commercial Space Transportation Advisory Committee; Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Open Meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

78 FR 53497 - Commercial Space Transportation Advisory Committee; Closed Session

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a...), notice is hereby given of a special closed session of the Commercial Space Transportation Advisory...

76 FR 51461 - Commercial Space Transportation Advisory Committee-Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee open meeting. SUMMARY: Pursuant to Section 10(a)(2) of the... the Commercial Space Transportation Advisory Committee (COMSTAC). The meeting will take place on...

Organizing for low cost space operations - Status and plans

NASA Technical Reports Server (NTRS)

Lee, C.

1976-01-01

Design features of the Space Transportation System (vehicle reuse, low cost expendable components, simple payload interfaces, standard support systems) must be matched by economical operational methods to achieve low operating and payload costs. Users will be responsible for their own payloads and will be charged according to the services they require. Efficient use of manpower, simple documentation, simplified test, checkout, and flight planning are firm goals, together with flexibility for quick response to varying user needs. Status of the Shuttle hardware, plans for establishing low cost procedures, and the policy for user charges are discussed.

High-Payoff Space Transportation Design Approach with a Technology Integration Strategy

NASA Technical Reports Server (NTRS)

McCleskey, C. M.; Rhodes, R. E.; Chen, T.; Robinson, J.

2011-01-01

A general architectural design sequence is described to create a highly efficient, operable, and supportable design that achieves an affordable, repeatable, and sustainable transportation function. The paper covers the following aspects of this approach in more detail: (1) vehicle architectural concept considerations (including important strategies for greater reusability); (2) vehicle element propulsion system packaging considerations; (3) vehicle element functional definition; (4) external ground servicing and access considerations; and, (5) simplified guidance, navigation, flight control and avionics communications considerations. Additionally, a technology integration strategy is forwarded that includes: (a) ground and flight test prior to production commitments; (b) parallel stage propellant storage, such as concentric-nested tanks; (c) high thrust, LOX-rich, LOX-cooled first stage earth-to-orbit main engine; (d) non-toxic, day-of-launch-loaded propellants for upper stages and in-space propulsion; (e) electric propulsion and aero stage control.

High conductance values in π-folded molecular junctions

NASA Astrophysics Data System (ADS)

Carini, Marco; Ruiz, Marta P.; Usabiaga, Imanol; Fernández, José A.; Cocinero, Emilio J.; Melle-Franco, Manuel; Diez-Perez, Ismael; Mateo-Alonso, Aurelio

2017-05-01

Folding processes play a crucial role in the development of function in biomacromolecules. Recreating this feature on synthetic systems would not only allow understanding and reproducing biological functions but also developing new functions. This has inspired the development of conformationally ordered synthetic oligomers known as foldamers. Herein, a new family of foldamers, consisting of an increasing number of anthracene units that adopt a folded sigmoidal conformation by a combination of intramolecular hydrogen bonds and aromatic interactions, is reported. Such folding process opens up an efficient through-space charge transport channel across the interacting anthracene moieties. In fact, single-molecule conductance measurements carried out on this series of foldamers, using the scanning tunnelling microscopy-based break-junction technique, reveal exceptionally high conductance values in the order of 10-1 G0 and a low length decay constant of 0.02 Å-1 that exceed the values observed in molecular junctions that make use of through-space charge transport pathways.

Conceptual Design of a Single-Aisle Turboelectric Commercial Transport With Fuselage Boundary Layer Ingestion

NASA Technical Reports Server (NTRS)

Welstead, Jason R.; Felder, James L.

2016-01-01

A single-aisle commercial transport concept with a turboelectric propulsion system architecture was developed assuming entry into service in 2035 and compared to a similar technology conventional configuration. The turboelectric architecture consisted of two underwing turbofans with generators extracting power from the fan shaft and sending it to a rear fuselage, axisymmetric, boundary layer ingesting fan. Results indicate that the turbo- electric concept has an economic mission fuel burn reduction of 7%, and a design mission fuel burn reduction of 12% compared to the conventional configuration. An exploration of the design space was performed to better understand how the turboelectric architecture changes the design space, and system sensitivities were run to determine the sensitivity of thrust specific fuel consumption at top of climb and propulsion system weight to the motor power, fan pressure ratio, and electrical transmission efficiency of the aft boundary layer ingesting fan.

Constellation Commodities Studies Summary

NASA Technical Reports Server (NTRS)

Dirschka, Eric

2011-01-01

Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

Path Toward a Unifid Geometry for Radiation Transport

NASA Technical Reports Server (NTRS)

Lee, Kerry; Barzilla, Janet; Davis, Andrew; Zachmann

2014-01-01

The Direct Accelerated Geometry for Radiation Analysis and Design (DAGRAD) element of the RadWorks Project under Advanced Exploration Systems (AES) within the Space Technology Mission Directorate (STMD) of NASA will enable new designs and concepts of operation for radiation risk assessment, mitigation and protection. This element is designed to produce a solution that will allow NASA to calculate the transport of space radiation through complex computer-aided design (CAD) models using the state-of-the-art analytic and Monte Carlo radiation transport codes. Due to the inherent hazard of astronaut and spacecraft exposure to ionizing radiation in low-Earth orbit (LEO) or in deep space, risk analyses must be performed for all crew vehicles and habitats. Incorporating these analyses into the design process can minimize the mass needed solely for radiation protection. Transport of the radiation fields as they pass through shielding and body materials can be simulated using Monte Carlo techniques or described by the Boltzmann equation, which is obtained by balancing changes in particle fluxes as they traverse a small volume of material with the gains and losses caused by atomic and nuclear collisions. Deterministic codes that solve the Boltzmann transport equation, such as HZETRN [high charge and energy transport code developed by NASA Langley Research Center (LaRC)], are generally computationally faster than Monte Carlo codes such as FLUKA, GEANT4, MCNP(X) or PHITS; however, they are currently limited to transport in one dimension, which poorly represents the secondary light ion and neutron radiation fields. NASA currently uses HZETRN space radiation transport software, both because it is computationally efficient and because proven methods have been developed for using this software to analyze complex geometries. Although Monte Carlo codes describe the relevant physics in a fully three-dimensional manner, their computational costs have thus far prevented their widespread use for analysis of complex CAD models, leading to the creation and maintenance of toolkit-specific simplistic geometry models. The work presented here builds on the Direct Accelerated Geometry Monte Carlo (DAGMC) toolkit developed for use with the Monte Carlo N-Particle (MCNP) transport code. The workflow for achieving radiation transport on CAD models using MCNP and FLUKA has been demonstrated and the results of analyses on realistic spacecraft/habitats will be presented. Future work is planned that will further automate this process and enable the use of multiple radiation transport codes on identical geometry models imported from CAD. This effort will enhance the modeling tools used by NASA to accurately evaluate the astronaut space radiation risk and accurately determine the protection provided by as-designed exploration mission vehicles and habitats

NASA's Ares I and Ares V Launch Vehicles--Effective Space Operations Through Efficient Ground Operations

NASA Technical Reports Server (NTRS)

Singer, Christopher E.; Dumbacher, Daniel L.; Lyles, Gary M.; Onken, Jay F.

2008-01-01

The United States (U.S.) is charting a renewed course for lunar exploration, with the fielding of a new human-rated space transportation system to replace the venerable Space Shuttle, which will be retired after it completes its missions of building the International Space Station (ISS) and servicing the Hubble Space Telescope. Powering the future of space-based scientific exploration will be the Ares I Crew Launch Vehicle, which will transport the Orion Crew Exploration Vehicle to orbit where it will rendezvous with the Altair Lunar Lander, which will be delivered by the Ares V Cargo Launch Vehicle (fig. 1). This configuration will empower rekindled investigation of Earth's natural satellite in the not too distant future. This new exploration infrastructure, developed by the National Aeronautics and Space Administration (NASA), will allow astronauts to leave low-Earth orbit (LEO) for extended lunar missions and preparation for the first long-distance journeys to Mars. All space-based operations - to LEO and beyond - are controlled from Earth. NASA's philosophy is to deliver safe, reliable, and cost-effective architecture solutions to sustain this multi-billion-dollar program across several decades. Leveraging SO years of lessons learned, NASA is partnering with private industry and academia, while building on proven hardware experience. This paper outlines a few ways that the Engineering Directorate at NASA's Marshall Space Flight Center is working with the Constellation Program and its project offices to streamline ground operations concepts by designing for operability, which reduces lifecycle costs and promotes sustainable space exploration.

The role of three-dimensional transport in driving enhanced electron acceleration during magnetic reconnection

NASA Astrophysics Data System (ADS)

Swisdak, M.; Dahlin, J. T.; Drake, J. F.

2017-12-01

Magnetic reconnection is an important driver of energetic particles in many space and astrophysical phenomena. Using kinetic particle-in-cell simulations, we explore the effects that the dynamics in three-dimensions has on reconnection and the efficiency of particle acceleration. In two-dimensional systems, Alfvenic outflows expel energetic electrons into flux ropes where they become trapped and disconnected from acceleration regions. However, in three-dimensional systems these flux ropes develop axial structure that enables particles to leak out and return to acceleration regions. This requires a finite guide field so that particles may move quickly along the flux rope axis. The greatest energetic electron production occurs when the guide field is of the same order as the reconnecting component: large enough to facilitate strong transport, but not so large as to throttle the dominant Fermi mechanism responsible for efficient electron acceleration.

Innovative Airbreathing Propulsion Concepts for High-speed Applications

NASA Technical Reports Server (NTRS)

Whitlow, Woodrow, Jr.

2002-01-01

The current cost to launch payloads to low earth orbit (LEO) is approximately loo00 U.S. dollars ($) per pound ($22000 per kilogram). This high cost limits our ability to pursue space science and hinders the development of new markets and a productive space enterprise. This enterprise includes NASA's space launch needs and those of industry, universities, the military, and other U.S. government agencies. NASA's Advanced Space Transportation Program (ASTP) proposes a vision of the future where space travel is as routine as in today's commercial air transportation systems. Dramatically lower launch costs will be required to make this vision a reality. In order to provide more affordable access to space, NASA has established new goals in its Aeronautics and Space Transportation plan. These goals target a reduction in the cost of launching payloads to LEO to $lo00 per pound ($2200 per kilogram) by 2007 and to $100' per pound by 2025 while increasing safety by orders of magnitude. Several programs within NASA are addressing innovative propulsion systems that offer potential for reducing launch costs. Various air-breathing propulsion systems currently are being investigated under these programs. The NASA Aerospace Propulsion and Power Base Research and Technology Program supports long-term fundamental research and is managed at GLenn Research Center. Currently funded areas relevant to space transportation include hybrid hyperspeed propulsion (HHP) and pulse detonation engine (PDE) research. The HHP Program currently is addressing rocket-based combined cycle and turbine-based combined cycle systems. The PDE research program has the goal of demonstrating the feasibility of PDE-based hybrid-cycle and combined cycle propulsion systems that meet NASA's aviation and access-to-space goals. The ASTP also is part of the Base Research and Technology Program and is managed at the Marshall Space Flight Center. As technologies developed under the Aerospace Propulsion and Power Base Research and Technology Program mature, they are incorporated into ASTP. One example of this is rocket-based combined cycle systems that are being considered as part of ASTP. The NASA Ultra Efficient Engine Technology (UEET) Program has the goal of developing propulsion system component technology that is relevant to a wide range of vehicle missions. In addition to subsonic and supersonic speed regimes, it includes the hypersonic speed regime. More specifically, component technologies for turbine-based combined cycle engines are being developed as part of UEET.

IPOLE - semi-analytic scheme for relativistic polarized radiative transport

NASA Astrophysics Data System (ADS)

Mościbrodzka, M.; Gammie, C. F.

2018-03-01

We describe IPOLE, a new public ray-tracing code for covariant, polarized radiative transport. The code extends the IBOTHROS scheme for covariant, unpolarized transport using two representations of the polarized radiation field: In the coordinate frame, it parallel transports the coherency tensor; in the frame of the plasma it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is implemented to be as spacetime- and coordinate- independent as possible. The emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, IPOLE is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth. We show that the code matches analytic results in flat space, and that it produces results that converge to those produced by Dexter's GRTRANS polarized transport code on a complicated model problem. We expect IPOLE will mainly find applications in modelling Event Horizon Telescope sources, but it may also be useful in other relativistic transport problems such as modelling for the IXPE mission.

KSC-2012-1329

NASA Image and Video Library

2012-02-14

COCOA BEACH, Fla. -- Ed Mango, program manager for NASA's Commercial Crew Program CCP, talks to industry partners and stakeholders during a preproposal conference at the Courtyard Marriott in Cocoa Beach, Fla. At left, are Cheryl McPhillips, the NASA Participant Evaluation Panel PEP chair for the Commercial Crew Program CCP, and Lee Pagel, the NASA PEP deputy. The meeting focused on information related to NASA's release of the Commercial Crew Integrated Capability CCiCap Announcement for Proposals on Feb. 7. More than 50 people from 25 aerospace companies attended the conference to find out what the space agency would be looking for in terms of milestones, funding, schedules, strategies, safety cultures, business modules and eventual flight certification standards of integrated crew space transportation systems. The goal of the CCiCap is to develop an indigenous U.S. transportation system that can safely, affordably and routinely fly to low Earth orbit destinations, including the International Space Station. Proposals are due March 23 and NASA plans to award multiple Space Act Agreements, valued from $300 million to $500 million each, toward the development of fully integrated commercial crew transportation systems in the summer of 2012. For more information, visit www.nasa.gov/commercialcrew Photo credit: Kim Shiflett The Ground Systems Development and Operations Program is developing the necessary ground systems, infrastructure and operational approaches required to safely process, assemble, transport and launch the next generation of rockets and spacecraft in support of NASA’s exploration objectives. Future work also will replace the antiquated communications, power and vehicle access resources with modern efficient systems. Some of the utilities and systems slated for replacement have been used since the VAB opened in 1965. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Kim Shiflett

Space transportation forecast conference, February 9-10, 1999 : Quarterly Launch Report : special report

DOT National Transportation Integrated Search

1999-02-01

Speakers at this conference presented an overview of commercial space transportation, calling conference participants visionaries" and emphasized the FAA's commitment to commercial space transportation, safety for all commercial space transportation ...

Service on demand for ISS users

NASA Astrophysics Data System (ADS)

Hüser, Detlev; Berg, Marco; Körtge, Nicole; Mildner, Wolfgang; Salmen, Frank; Strauch, Karsten

2002-07-01

Since the ISS started its operational phase, the need of logistics scenarios and solutions, supporting the utilisation of the station and its facilities, becomes increasingly important. Our contribution to this challenge is a SERVICE On DEMAND for ISS users, which offers a business friendly engineering and logistics support for the resupply of the station. Especially the utilisation by commercial and industrial users is supported and simplified by this service. Our industrial team, consisting of OHB-System and BEOS, provides experience and development support for space dedicated hard- and software elements, their transportation and operation. Furthermore, we operate as the interface between customer and the envisaged space authorities. Due to a variety of tailored service elements and the ongoing servicing, customers can concentrate on their payload content or mission objectives and don't have to deal with space-specific techniques and regulations. The SERVICE On DEMAND includes the following elements: ITR is our in-orbit platform service. ITR is a transport rack, used in the SPACEHAB logistics double module, for active and passive payloads on subrack- and drawer level of different standards. Due to its unique late access and early retrieval capability, ITR increases the flexibility concerning transport capabilities to and from the ISS. RIST is our multi-functional test facility for ISPR-based experiment drawer and locker payloads. The test program concentrates on physical and functional interface and performance testing at the payload developers site prior to the shipment to the integration and launch. The RIST service program comprises consulting, planning and engineering as well. The RIST test suitcase is planned to be available for lease or rent to users, too. AMTSS is an advanced multimedia terminal consulting service for communication with the space station scientific facilities, as part of the user home-base. This unique ISS multimedia kit combines communication technologies, software tools and hardware to provide a simple and cost-efficient access to data from the station, using the interconnection ground subnetwork. BEOLOG is our efficient ground logistics service for the transportation of payload hardware and support equipment from the user location to the launch/landing sites for the ISS service flights and back home. The main function of this service is the planning and organisation of all packaging, handling, storage & transportation tasks according to international rules. In conclusion, we offer novel service elements for logistics ground- and flight-infrastructure, dedicated for ISS users. These services can be easily adapted to the needs of users and are suitable for other μg- platforms as well.

Space transportation forecast conference, February 10-11, 1998 : Quarterly Launch Report : special report

DOT National Transportation Integrated Search

1998-01-01

The Federal Aviation Administration's Associate Administrator for Commercial Space Transportation (AST) convened the first national commercial space transportation forecast conference on February 10-11, 1998. For the theme, Commercial Space Transport...

Low temperature storage container for transporting perishables to space station

NASA Technical Reports Server (NTRS)

Dean, William G (Inventor); Owen, James W. (Inventor)

1988-01-01

This invention is directed to the long term storage of frozen and refrigerated food and biological samples by the space shuttle to the space station. A storage container is utilized which has a passive system so that fluid/thermal and electrical interfaces with the logistics module is not required. The container for storage comprises two units, each having an inner storage shell and an outer shell receiving the inner shell and spaced about it. The novelty appears to lie in the integration of thermally efficient cryogenic storage techniques with phase change materials, including the multilayer metalized surface thin plastic film insulation and the vacuum between the shells. Additionally the fiberglass constructed shells having fiberglass honeycomb portions, and the lining of the space between the shells with foil combine to form a storage container which may keep food and biological samples at very low temperatures for very long periods of time utilizing a passive system.

High-Temperature, Thin-Film Ceramic Thermocouples Developed

NASA Technical Reports Server (NTRS)

Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

2005-01-01

To enable long-duration, more distant human and robotic missions for the Vision for Space Exploration, as well as safer, lighter, quieter, and more fuel efficient vehicles for aeronautics and space transportation, NASA is developing instrumentation and material technologies. The high-temperature capabilities of thin-film ceramic thermocouples are being explored at the NASA Glenn Research Center by the Sensors and Electronics Branch and the Ceramics Branch in partnership with Case Western Reserve University (CWRU). Glenn s Sensors and Electronics Branch is developing thin-film sensors for surface measurement of strain, temperature, heat flux, and surface flow in propulsion system research. Glenn s Ceramics Branch, in conjunction with CWRU, is developing structural and functional ceramic technology for aeropropulsion and space propulsion.

NASA Advanced Computing Environment for Science and Engineering

NASA Technical Reports Server (NTRS)

Biswas, Rupak

2017-01-01

Vision: To reach for new heights and reveal the unknown so that what we do and learn will benefit all humankind. Mission: To pioneer the future in space exploration, scientific discovery, and aeronautics research. Aeronautics Research (ARMD): Pioneer and prove new flight technologies for safer, more secure, efficient, and environmental friendly air transportation. Human Exploration and Operations (HEOMD): Focus on ISS operations; and develop new spacecraft and other capabilities for affordable, sustainable exploration beyond low Earth orbit. Science (SCMD): Explore the Earth, solar system, and universe beyond; chart best route for discovery; and reap the benefits of Earth and space exploration for society. Space Technology (STMD): Rapidly develop, demonstrate, and infuse revolutionary, high-payoff technologies through collaborative partnerships, expanding the boundaries of aerospace enterprise.

A Coupled Probabilistic Wake Vortex and Aircraft Response Prediction Model

NASA Technical Reports Server (NTRS)

Gloudemans, Thijs; Van Lochem, Sander; Ras, Eelco; Malissa, Joel; Ahmad, Nashat N.; Lewis, Timothy A.

2016-01-01

Wake vortex spacing standards along with weather and runway occupancy time, restrict terminal area throughput and impose major constraints on the overall capacity and efficiency of the National Airspace System (NAS). For more than two decades, the National Aeronautics and Space Administration (NASA) has been conducting research on characterizing wake vortex behavior in order to develop fast-time wake transport and decay prediction models. It is expected that the models can be used in the systems level design of advanced air traffic management (ATM) concepts that safely increase the capacity of the NAS. It is also envisioned that at a later stage of maturity, these models could potentially be used operationally, in groundbased spacing and scheduling systems as well as on the flight deck.

77 FR 14462 - Space Transportation Infrastructure Matching Grants Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-09

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Space Transportation Infrastructure... grant proposals for the Space Transportation Infrastructure Matching Grants Program. SUMMARY: This notice solicits Fiscal Year (FY) 2012 grant proposals to continue the development of a Commercial Space...

Development of Structural Energy Storage for Aeronautics Applications

NASA Technical Reports Server (NTRS)

Santiago-Dejesus, Diana; Loyselle, Patricia L.; Demattia, Brianne; Bednarcyk, Brett; Olson, Erik; Smith, Russell; Hare, David

2017-01-01

The National Aeronautics and Space Administration (NASA) has identified Multifunctional Structures for High Efficiency Lightweight Load-bearing Storage (M-SHELLS) as critical to development of hybrid gas-electric propulsion for commercial aeronautical transport in the N+3 timeframe. The established goals include reducing emissions by 80 and fuel consumption by 60 from todays state of the art. The advancement will enable technology for NASA Aeronautics Research Mission Directorates (ARMD) Strategic Thrust 3 to pioneer big leaps in efficiency and environmental performance for ultra-efficient commercial transports, as well as Strategic Thrust 4 to pioneer low-carbon propulsion technology in the transition to that scheme. The M-SHELLS concept addresses the hybrid gas-electric highest risk with its primary objective: to save structures energy storage system weight for future commercial hybrid electric propulsion aircraft by melding the load-carrying structure with energy storage in a single material. NASA's multifunctional approach also combines supercapacitor and battery chemistries in a synergistic energy storage arrangement in tandem with supporting good mechanical properties. The arrangement provides an advantageous combination of specific power, energy, and strength.

Particle Acceleration and Fractional Transport in Turbulent Reconnection

NASA Astrophysics Data System (ADS)

Isliker, Heinz; Pisokas, Theophilos; Vlahos, Loukas; Anastasiadis, Anastasios

2017-11-01

We consider a large-scale environment of turbulent reconnection that is fragmented into a number of randomly distributed unstable current sheets (UCSs), and we statistically analyze the acceleration of particles within this environment. We address two important cases of acceleration mechanisms when particles interact with the UCS: (a) electric field acceleration and (b) acceleration by reflection at contracting islands. Electrons and ions are accelerated very efficiently, attaining an energy distribution of power-law shape with an index 1-2, depending on the acceleration mechanism. The transport coefficients in energy space are estimated from test-particle simulation data, and we show that the classical Fokker-Planck (FP) equation fails to reproduce the simulation results when the transport coefficients are inserted into it and it is solved numerically. The cause for this failure is that the particles perform Levy flights in energy space, while the distributions of the energy increments exhibit power-law tails. We then use the fractional transport equation (FTE) derived by Isliker et al., whose parameters and the order of the fractional derivatives are inferred from the simulation data, and solving the FTE numerically, we show that the FTE successfully reproduces the kinetic energy distribution of the test particles. We discuss in detail the analysis of the simulation data and the criteria that allow one to judge the appropriateness of either an FTE or a classical FP equation as a transport model.

Particle Acceleration and Fractional Transport in Turbulent Reconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isliker, Heinz; Pisokas, Theophilos; Vlahos, Loukas

We consider a large-scale environment of turbulent reconnection that is fragmented into a number of randomly distributed unstable current sheets (UCSs), and we statistically analyze the acceleration of particles within this environment. We address two important cases of acceleration mechanisms when particles interact with the UCS: (a) electric field acceleration and (b) acceleration by reflection at contracting islands. Electrons and ions are accelerated very efficiently, attaining an energy distribution of power-law shape with an index 1–2, depending on the acceleration mechanism. The transport coefficients in energy space are estimated from test-particle simulation data, and we show that the classical Fokker–Planckmore » (FP) equation fails to reproduce the simulation results when the transport coefficients are inserted into it and it is solved numerically. The cause for this failure is that the particles perform Levy flights in energy space, while the distributions of the energy increments exhibit power-law tails. We then use the fractional transport equation (FTE) derived by Isliker et al., whose parameters and the order of the fractional derivatives are inferred from the simulation data, and solving the FTE numerically, we show that the FTE successfully reproduces the kinetic energy distribution of the test particles. We discuss in detail the analysis of the simulation data and the criteria that allow one to judge the appropriateness of either an FTE or a classical FP equation as a transport model.« less

Analysis of ballistic transport in nanoscale devices by using an accelerated finite element contact block reduction approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, H.; Li, G., E-mail: gli@clemson.edu

2014-08-28

An accelerated Finite Element Contact Block Reduction (FECBR) approach is presented for computational analysis of ballistic transport in nanoscale electronic devices with arbitrary geometry and unstructured mesh. Finite element formulation is developed for the theoretical CBR/Poisson model. The FECBR approach is accelerated through eigen-pair reduction, lead mode space projection, and component mode synthesis techniques. The accelerated FECBR is applied to perform quantum mechanical ballistic transport analysis of a DG-MOSFET with taper-shaped extensions and a DG-MOSFET with Si/SiO{sub 2} interface roughness. The computed electrical transport properties of the devices obtained from the accelerated FECBR approach and associated computational cost as amore » function of system degrees of freedom are compared with those obtained from the original CBR and direct inversion methods. The performance of the accelerated FECBR in both its accuracy and efficiency is demonstrated.« less

Low-Cost Approaches to III–V Semiconductor Growth for Photovoltaic Applications

DOE PAGES

Greenaway, Ann L.; Boucher, Jason W.; Oener, Sebastian Z.; ...

2017-08-31

III–V semiconductors form the most efficient single- and multijunction photovoltaics. Metal–organic vapor-phase epitaxy, which uses toxic and pyrophoric gas-phase precursors, is the primary commercial growth method for these materials. In order for the use of highly efficient III–V-based devices to be expanded as the demand for renewable electricity grows, a lower-cost approach to the growth of these materials is needed. This Review focuses on three deposition techniques compatible with current device architectures: hydride vapor-phase epitaxy, close-spaced vapor transport, and thin-film vapor–liquid–solid growth. Here, we consider recent advances in each technique, including the available materials space, before providing an in-depth comparisonmore » of growth technology advantages and limitations and considering the impact of modifications to the method of production on the cost of the final photovoltaics.« less

76 FR 82031 - Commercial Space Transportation Advisory Committee; Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-29

... conducted by AST because of its knowledge and resources in the commercial space industry. The purpose of the... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation...: Notice of Commercial Space Transportation Advisory Committee Risk Management Working Group Teleconference...

Design concepts for bioreactors in space

NASA Technical Reports Server (NTRS)

Seshan, P. K.; Peterson, G. R.; Beard, B.; Dunlop, E. H.

1986-01-01

Microbial food sources are becoming viable and more efficient alternatives to conventional food sources especially in the context of Closed Ecological Life Support Systems (CELSS) in space habitats. Since bioreactor designs for terrestrial operation will not readily apply to conditions of microgravity, there is an urgent need to learn about the differences. These differences cannot be easily estimated due to the complex nature of the mass transport and mixing mechanisms in fermenters. Therefore, a systematic and expeditious experimental program must be undertaken to obtain the engineering data necessary to lay down the foundations of designing bioreactors for microgravity. Two bioreactor design concepts presented represent two dissimilar approaches to grappling with the absence of gravity in space habitats and deserve to be tested for adoption as important components of the life support function aboard spacecrafts, space stations and other extra-terrestrial habitats.

A characteristics-based method for solving the transport equation and its application to the process of mantle differentiation and continental root growth

NASA Astrophysics Data System (ADS)

de Smet, Jeroen H.; van den Berg, Arie P.; Vlaar, Nico J.; Yuen, David A.

2000-03-01

Purely advective transport of composition is of major importance in the Geosciences, and efficient and accurate solution methods are needed. A characteristics-based method is used to solve the transport equation. We employ a new hybrid interpolation scheme, which allows for the tuning of stability and accuracy through a threshold parameter ɛth. Stability is established by bilinear interpolations, and bicubic splines are used to maintain accuracy. With this scheme, numerical instabilities can be suppressed by allowing numerical diffusion to work in time and locally in space. The scheme can be applied efficiently for preliminary modelling purposes. This can be followed by detailed high-resolution experiments. First, the principal effects of this hybrid interpolation method are illustrated and some tests are presented for numerical solutions of the transport equation. Second, we illustrate that this approach works successfully for a previously developed continental evolution model for the convecting upper mantle. In this model the transport equation contains a source term, which describes the melt production in pressure-released partial melting. In this model, a characteristic phenomenon of small-scale melting diapirs is observed (De Smet et al.1998; De Smet et al. 1999). High-resolution experiments with grid cells down to 700m horizontally and 515m vertically result in highly detailed observations of the diapiric melting phenomenon.

77 FR 58607 - Office of Commercial Space Transportation Safety Approval Performance Criteria

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-21

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Office of Commercial Space...), FAA Office of Commercial Space Transportation (AST), 800 Independence Avenue SW., Room 331, Washington... September 17, 2012. George C. Nield, Associate Administrator for Commercial Space Transportation. [FR Doc...

Role of Near Substrate and Bulk Polymer Morphology on Out-of-Plane Space-Charge Limited Hole Mobility.

PubMed

Turner, Johnathan; Gadisa, Abay

2016-12-07

Charge transport is a central issue in all types of organic electronic devices. In organic films, charge transport is crucially limited by film microstructure and the nature of the substrate/organic interface interactions. In this report, we discuss the influence of active layer thickness on space-charge limited hole transport in pristine polymer and polymer/fullerene bulk heterojunction thin films (∼15-300 nm) in a diode structure. According to the results, the out-of-plane hole mobility in pristine polymers is sensitive to the degree of polymer chain aggregation. Blending the polymers with a fullerene molecule does not change the trend of hole mobility if the polymer tends to make an amorphous structure. However, employing an aggregating polymer in a bulk heterojunction blend gives rise to a marked difference in charge carrier transport behavior compared to the pristine polymer and this difference is sensitive to active layer thickness. In aggregating polymer films, the thickness-dependent interchain interaction was found to have direct impact on hole mobility. The thickness-dependent mobility trend was found to correspond well with the trend of fill factors of corresponding bulk heterojunction solar cells. This investigation has a vital implication for material design and the development of efficient organic electronic devices, including solar cells and light-emitting diodes.

Self-pinched lithium beam transport experiments on SABRE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, D.L.; Olson, C.L.; Poukey, J.W.

Self-pinched transport of ion beams has many advantages for ion-driven ICF applications involving high yield and energy production. The authors are currently preparing for a self-pinched lithium beam transport experiment on the SABRE accelerator. There are three transport elements that must eventually be demonstrated: (1) efficient lithium beam generation and ballistic transport to a focus at the self-pinched transport channel entrance; (2) self-pinched transport in the channel, requiring optimized injection conditions and gas breakdown; and (3) self-pinched transport of the equilibrated beam from the channel into free space, with associated aiming and stability considerations. In the present experiment, a hollowmore » annular lithium beam from an applied-B extraction ion diode will be focused to small radius (r {le} 2 cm) in a 60 cm long ballistic focus section containing argon gas at a pressure of a few Torr. The self-pinched transport channel will contain a low pressure background gas of 10--40 mTorr argon to allow sufficient net current to confine the beam for long distance transport. IPROP simulations are in progress to optimize the design of the ballistic and self-pinched transport sections. Progress on preparation of this lithium self-pinched transport experiment, including a discussion of transport system design, important gas breakdown issues, and diagnostics, will be presented.« less

Visions of tomorrow: A focus on national space transportation issues; Proceedings of the Twenty-fifth Goddard Memorial Symposium, Greenbelt, MD, Mar. 18-20, 1987

NASA Technical Reports Server (NTRS)

Soffen, Gerald A. (Editor)

1987-01-01

The present conference on U.S. space transportation systems development discusses opportunities for aerospace students in prospective military, civil, industrial, and scientific programs, current strategic conceptualization and program planning for future U.S. space transportation, the DOD space transportation plan, NASA space transportation plans, medium launch vehicle and commercial space launch services, the capabilities and availability of foreign launch vehicles, and the role of commercial space launch systems. Also discussed are available upper stage systems, future space transportation needs for space science and applications, the trajectory analysis of a low lift/drag-aeroassisted orbit transfer vehicle, possible replacements for the Space Shuttle, LEO to GEO with combined electric/beamed-microwave power from earth, the National Aerospace Plane, laser propulsion to earth orbit, and a performance analysis for a laser-powered SSTO vehicle.

Efficient determination of the Markovian time-evolution towards a steady-state of a complex open quantum system

NASA Astrophysics Data System (ADS)

Jonsson, Thorsteinn H.; Manolescu, Andrei; Goan, Hsi-Sheng; Abdullah, Nzar Rauf; Sitek, Anna; Tang, Chi-Shung; Gudmundsson, Vidar

2017-11-01

Master equations are commonly used to describe time evolution of open systems. We introduce a general computationally efficient method for calculating a Markovian solution of the Nakajima-Zwanzig generalized master equation. We do so for a time-dependent transport of interacting electrons through a complex nano scale system in a photon cavity. The central system, described by 120 many-body states in a Fock space, is weakly coupled to the external leads. The efficiency of the approach allows us to place the bias window defined by the external leads high into the many-body spectrum of the cavity photon-dressed states of the central system revealing a cascade of intermediate transitions as the system relaxes to a steady state. The very diverse relaxation times present in the open system, reflecting radiative or non-radiative transitions, require information about the time evolution through many orders of magnitude. In our approach, the generalized master equation is mapped from a many-body Fock space of states to a Liouville space of transitions. We show that this results in a linear equation which is solved exactly through an eigenvalue analysis, which supplies information on the steady state and the time evolution of the system.

2006 Status of the Momentum eXchange Electrodynamic Re-Boost (MXER) Tether Development

NASA Technical Reports Server (NTRS)

Bonometti, Joseph A.; Sorensen, Kirk F.; Dankanich, John W.; Frame, Kyle L.

2006-01-01

The MXER Tether technology development is a high-payoff/high-risk investment area within the NASA In-Space Propulsion Technology (ISPT) Program. The ISPT program is managed by the NASA Headquarters Science Mission Directorate and implemented by the Marshall Space Flight Center in Huntsville, Alabama. The MXER concept was identified and competitively ranked within NASA's comprehensive Integrated In-Space Transportation Plan (IISTP); an agency-wide technology assessment activity. The objective of the MXER tether project within ISPT is to advance the technological maturation level for the MXER system, and its subsystems, as well as other space and terrestrial tether applications. Recent hardware efforts have focused on the manufacturability of space-survivable high-strength tether material and coatings, high-current electrodynamic tether, lightweight catch mechanism, high-accuracy propagator/predictor code, and efficient electron collection/current generation. Significant technical progress has been achieved with modest ISPT funding to the extent that MXER has evolved to a well-characterized system with greater capability as the design has been matured. Synergistic efforts in high-current electrodynamic tethers and efficient electron collection/current generation have been made possible through SBIR and STTR support. The entire development endeavor was orchestrated as a collaborative team effort across multiple individual contracts and has established a solid technology resource base, which permits a wide variety of future space cable/tether applications to be realized.

Spatial spread of an epidemic through public transportation systems with a hub.

PubMed

Xu, Fei; Connell McCluskey, C; Cressman, Ross

2013-11-01

This article investigates an epidemic spreading among several locations through a transportation system, with a hub connecting these locations. Public transportation is not only a bridge through which infections travel from one location to another but also a place where infections occur since individuals are typically in close proximity to each other due to the limited space in these systems. A mathematical model is constructed to study the spread of an infectious disease through such systems. A variant of the next generation method is proposed and used to provide upper and lower bounds of the basic reproduction number for the model. Our investigation indicates that increasing transportation efficiency, and improving sanitation and ventilation of the public transportation system decrease the chance of an outbreak occurring. Moreover, discouraging unnecessary travel during an epidemic also decreases the chance of an outbreak. However, reducing travel by infectives while allowing susceptibles to travel may not be enough to avoid an outbreak. Copyright © 2013 Elsevier Inc. All rights reserved.

Charge transport in organic semiconductors.

PubMed

Bässler, Heinz; Köhler, Anna

2012-01-01

Modern optoelectronic devices, such as light-emitting diodes, field-effect transistors and organic solar cells require well controlled motion of charges for their efficient operation. The understanding of the processes that determine charge transport is therefore of paramount importance for designing materials with improved structure-property relationships. Before discussing different regimes of charge transport in organic semiconductors, we present a brief introduction into the conceptual framework in which we interpret the relevant photophysical processes. That is, we compare a molecular picture of electronic excitations against the Su-Schrieffer-Heeger semiconductor band model. After a brief description of experimental techniques needed to measure charge mobilities, we then elaborate on the parameters controlling charge transport in technologically relevant materials. Thus, we consider the influences of electronic coupling between molecular units, disorder, polaronic effects and space charge. A particular focus is given to the recent progress made in understanding charge transport on short time scales and short length scales. The mechanism for charge injection is briefly addressed towards the end of this chapter.

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

NASA Astrophysics Data System (ADS)

Doisneau, François; Arienti, Marco; Oefelein, Joseph C.

2017-01-01

For sprays, as described by a kinetic disperse phase model strongly coupled to the Navier-Stokes equations, the resolution strategy is constrained by accuracy objectives, robustness needs, and the computing architecture. In order to leverage the good properties of the Eulerian formalism, we introduce a deterministic particle-based numerical method to solve transport in physical space, which is simple to adapt to the many types of closures and moment systems. The method is inspired by the semi-Lagrangian schemes, developed for Gas Dynamics. We show how semi-Lagrangian formulations are relevant for a disperse phase far from equilibrium and where the particle-particle coupling barely influences the transport; i.e., when particle pressure is negligible. The particle behavior is indeed close to free streaming. The new method uses the assumption of parcel transport and avoids to compute fluxes and their limiters, which makes it robust. It is a deterministic resolution method so that it does not require efforts on statistical convergence, noise control, or post-processing. All couplings are done among data under the form of Eulerian fields, which allows one to use efficient algorithms and to anticipate the computational load. This makes the method both accurate and efficient in the context of parallel computing. After a complete verification of the new transport method on various academic test cases, we demonstrate the overall strategy's ability to solve a strongly-coupled liquid jet with fine spatial resolution and we apply it to the case of high-fidelity Large Eddy Simulation of a dense spray flow. A fuel spray is simulated after atomization at Diesel engine combustion chamber conditions. The large, parallel, strongly coupled computation proves the efficiency of the method for dense, polydisperse, reacting spray flows.

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doisneau, François, E-mail: fdoisne@sandia.gov; Arienti, Marco, E-mail: marient@sandia.gov; Oefelein, Joseph C., E-mail: oefelei@sandia.gov

For sprays, as described by a kinetic disperse phase model strongly coupled to the Navier–Stokes equations, the resolution strategy is constrained by accuracy objectives, robustness needs, and the computing architecture. In order to leverage the good properties of the Eulerian formalism, we introduce a deterministic particle-based numerical method to solve transport in physical space, which is simple to adapt to the many types of closures and moment systems. The method is inspired by the semi-Lagrangian schemes, developed for Gas Dynamics. We show how semi-Lagrangian formulations are relevant for a disperse phase far from equilibrium and where the particle–particle coupling barelymore » influences the transport; i.e., when particle pressure is negligible. The particle behavior is indeed close to free streaming. The new method uses the assumption of parcel transport and avoids to compute fluxes and their limiters, which makes it robust. It is a deterministic resolution method so that it does not require efforts on statistical convergence, noise control, or post-processing. All couplings are done among data under the form of Eulerian fields, which allows one to use efficient algorithms and to anticipate the computational load. This makes the method both accurate and efficient in the context of parallel computing. After a complete verification of the new transport method on various academic test cases, we demonstrate the overall strategy's ability to solve a strongly-coupled liquid jet with fine spatial resolution and we apply it to the case of high-fidelity Large Eddy Simulation of a dense spray flow. A fuel spray is simulated after atomization at Diesel engine combustion chamber conditions. The large, parallel, strongly coupled computation proves the efficiency of the method for dense, polydisperse, reacting spray flows.« less

Special investigation report: Commercial space launch incident, launch procedure anomaly orbital sciences corporation PEGASUS/SCD-1, 80 nautical miles east of Cape Canaveral, Florida, February 9, 1993

NASA Astrophysics Data System (ADS)

This report explains the procedural anomaly that occurred during the launch sequence of an Orbital Sciences Corporation Pegasus expendable launch vehicle, which was subsequently deployed successfully from an NB-52B airplane, on 9 Feb. 1993. The safety issues discussed in the report include command, control and communications responsibility, launch crew fatigue, launch interphone procedures, efficiency of launch constraints, and the lack of common launch documents. Safety recommendations concerning these issues were made to the Department of Transportation, the National Aeronautics and Space Administration, and the Orbital Sciences Corporation.

Computer Model Of Fragmentation Of Atomic Nuclei

NASA Technical Reports Server (NTRS)

Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.

1995-01-01

High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.

Special Investigation Report: Commercial Space Launch Incident, Launch Procedure Anomaly Orbital Sciences Corporation PEGASUS/SCD-1, 80 Nautical Miles East of Cape Canaveral, Florida, February 9, 1993

NASA Technical Reports Server (NTRS)

1993-01-01

This report explains the procedural anomaly that occurred during the launch sequence of an Orbital Sciences Corporation Pegasus expendable launch vehicle, which was subsequently deployed successfully from an NB-52B airplane, on 9 Feb. 1993. The safety issues discussed in the report include command, control and communications responsibility, launch crew fatigue, launch interphone procedures, efficiency of launch constraints, and the lack of common launch documents. Safety recommendations concerning these issues were made to the Department of Transportation, the National Aeronautics and Space Administration, and the Orbital Sciences Corporation.

New Propulsion Technologies For Exploration of the Solar System and Beyond

NASA Technical Reports Server (NTRS)

Johnson, Les; Cook, Stephen (Technical Monitor)

2001-01-01

In order to implement the ambitious science and exploration missions planned over the next several decades, improvements in in-space transportation and propulsion technologies must be achieved. For robotic exploration and science missions, increased efficiencies of future propulsion systems are critical to reduce overall life-cycle costs. Future missions will require 2 to 3 times more total change in velocity over their mission lives than the NASA Solar Electric Technology Application Readiness (NSTAR) demonstration on the Deep Space 1 mission. Rendezvous and return missions will require similar investments in in-space propulsion systems. New opportunities to explore beyond the outer planets and to the stars will require unparalleled technology advancement and innovation. The Advanced Space Transportation Program (ASTP) is investing in technologies to achieve a factor of 10 reduction in the cost of Earth orbital transportation and a factor of 2 reduction in propulsion system mass and travel time for planetary missions within the next 15 years. Since more than 70% of projected launches over the next 10 years will require propulsion systems capable of attaining destinations beyond Low Earth Orbit, investment in in-space technologies will benefit a large percentage of future missions. The ASTP technology portfolio includes many advanced propulsion systems. From the next generation ion propulsion system operating in the 5 - 10 kW range, to fission-powered multi-kilowatt systems, substantial advances in spacecraft propulsion performance are anticipated. Some of the most promising technologies for achieving these goals use the environment of space itself for energy and propulsion and are generically called, "propellantless" because they do not require on-board fuel to achieve thrust. An overview of the state-of-the-art in propellantless propulsion technologies such as solar and plasma sails, electrodynamic and momentum transfer tethers, and aeroassist and aerocapture will also be described. Results of recent earth-based technology demonstrations and space tests for many of these new propulsion technologies will be discussed.

Biomimetics on seed dispersal: survey and insights for space exploration.

PubMed

Pandolfi, Camilla; Izzo, Dario

2013-06-01

Seeds provide the vital genetic link and dispersal agent between successive generations of plants. Without seed dispersal as a means of reproduction, many plants would quickly die out. Because plants lack any sort of mobility and remain in the same spot for their entire lives, they rely on seed dispersal to transport their offspring throughout the environment. This can be accomplished either collectively or individually; in any case as seeds ultimately abdicate their movement, they are at the mercy of environmental factors. Thus, seed dispersal strategies are characterized by robustness, adaptability, intelligence (both behavioral and morphological), and mass and energy efficiency (including the ability to utilize environmental sources of energy available): all qualities that advanced engineering systems aim at in general, and in particular those that need to enable complex endeavors such as space exploration. Plants evolved and adapted their strategy according to their environment, and taken together, they enclose many desirable characteristics that a space mission needs to have. Understanding in detail how plants control the development of seeds, fabricate structural components for their dispersal, build molecular machineries to keep seeds dormant up to the right moment and monitor the environment to release them at the right time could provide several solutions impacting current space mission design practices. It can lead to miniaturization, higher integration and packing efficiency, energy efficiency and higher autonomy and robustness. Consequently, there would appear to be good reasons for considering biomimetic solutions from plant kingdom when designing space missions, especially to other celestial bodies, where solid and liquid surfaces, atmosphere, etc constitute and are obviously parallel with the terrestrial environment where plants evolved. In this paper, we review the current state of biomimetics on seed dispersal to improve space mission design.

76 FR 12211 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference (COMSTAC). SUMMARY: Pursuant...

Compact, highly efficient, single-frequency 25W, 2051nm Tm fiber-based MOPA for CO2 trace-gas laser space transmitter

NASA Astrophysics Data System (ADS)

Engin, Doruk; Chuang, Ti; Litvinovitch, Slava; Storm, Mark

2017-08-01

Fibertek has developed and demonstrated an ideal high-power; low-risk; low-size, weight, and power (SWaP) 2051 nm laser design meeting the lidar requirements for satellite-based global measurement of carbon dioxide (CO2). The laser design provides a path to space for either a coherent lidar approach being developed by NASA Jet Propulsion Laboratory (JPL)1,2 or an Integrated Path Differential Lidar (IPDA) approach developed by Harris Corp using radio frequency (RF) modulation and being flown as part of a NASA Earth Venture Suborbital Mission—NASA's Atmospheric Carbon and Transport - America.3,4 The thulium (Tm) fiber laser amplifies a <500 kHz linewidth distributed feedback (DFB) laser up to 25 W average power in a polarization maintaining (PM) fiber. The design manages and suppresses all deleterious non-linear effects that can cause linewidth broadening or amplified spontaneous emission (ASE) and meets all lidar requirements. We believe the core laser components, architecture, and design margins can support a coherent or IPDA lidar 10-year space mission. With follow-on funding Fibertek can adapt an existing space-based Technology Readiness Level 6 (TRL-6), 20 W erbium fiber laser package for this Tm design and enable a near-term space mission with an electrical-to-optical (e-o) efficiency of <20%. A cladding-pumped PM Tm fiber-based amplifier optimized for high efficiency and high-power operation at 2051 nm is presented. The two-stage amplifier has been demonstrated to achieve 25 W average power and <16 dB polarization extinction ratio (PER) out of a single-mode PM fiber using a <500 kHz linewidth JPL DFB laser5-7 and 43 dB gain. The power amplifier's optical conversion efficiency is 53%. An internal efficiency of 58% is calculated after correcting for passive losses. The two-stage amplifier sustains its highly efficient operation for a temperature range of 5-40°C. The absence of stimulated Brillouin scattering (SBS) for the narrow linewidth amplification shows promise for further power scaling.

Aerospace Fuels From Nonpetroleum Raw Materials

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan A.; Hepp, Aloysius F.; Kulis, Michael J.; Jaworske, Donald A.

2013-01-01

Recycling human metabolic and plastic wastes minimizes cost and increases efficiency by reducing the need to transport consumables and return trash, respectively, from orbit to support a space station crew. If the much larger costs of transporting consumables to the Moon and beyond are taken into account, developing waste recycling technologies becomes imperative and possibly mission enabling. Reduction of terrestrial waste streams while producing energy and/or valuable raw materials is an opportunity being realized by a new generation of visionary entrepreneurs; several relevant technologies are briefly compared, contrasted and assessed for space applications. A two-step approach to nonpetroleum raw materials utilization is presented; the first step involves production of supply or producer gas. This is akin to synthesis gas containing carbon oxides, hydrogen, and simple hydrocarbons. The second step involves production of fuel via the Sabatier process, a methanation reaction, or another gas-to-liquid technology, typically Fischer-Tropsch processing. Optimization to enhance the fraction of product stream relevant to transportation fuels via catalytic (process) development at NASA Glenn Research Center is described. Energy utilization is a concern for production of fuels whether for operation on the lunar or Martian surface, or beyond. The term green relates to not only mitigating excess carbon release but also to the efficiency of energy usage. For space, energy usage can be an essential concern. Another issue of great concern is minimizing impurities in the product stream(s), especially those that are potential health risks and/or could degrade operations through catalyst poisoning or equipment damage; technologies being developed to remove heteroatom impurities are discussed. Alternative technologies to utilize waste fluids, such as a propulsion option called the resistojet, are discussed. The resistojet is an electric propulsion technology with a powered thruster to vaporize and heat a propellant to high temperature, hot gases are subsequently passed through a converging-diverging nozzle expanding gases to supersonic velocities. A resistojet can accommodate many different fluids, including various reaction chamber (by-)products.

Aerospace Fuels from Nonpetroleum Raw Materials

NASA Technical Reports Server (NTRS)

Palaszewski, B. A.; Hepp, A. F.; Kulis, M. J.; Jaworske, D. A.

2013-01-01

Recycling human metabolic and plastic wastes minimizes cost and increases efficiency by reducing the need to transport consumables and return trash, respectively, from orbit to support a space station crew. If the much larger costs of transporting consumables to the Moon and beyond are taken into account, developing waste recycling technologies becomes imperative and possibly mission enabling. Reduction of terrestrial waste streams while producing energy and/or valuable raw materials is an opportunity being realized by a new generation of visionary entrepreneurs; several relevant technologies are briefly compared, contrasted and assessed for space applications. A two-step approach to nonpetroleum raw materials utilization is presented; the first step involves production of supply or producer gas. This is akin to synthesis gas containing carbon oxides, hydrogen, and simple hydrocarbons. The second step involves production of fuel via the Sabatier process, a methanation reaction, or another gas-to-liquid technology, typically Fischer- Tropsch processing. Optimization to enhance the fraction of product stream relevant to transportation fuels via catalytic (process) development at NASA GRC is described. Energy utilization is a concern for production of fuels whether for operation on the lunar or Martian surface, or beyond. The term "green" relates to not only mitigating excess carbon release but also to the efficiency of energy usage. For space, energy usage can be an essential concern. Other issues of great concern include minimizing impurities in the product stream(s), especially those that are potential health risks and/or could de-grade operations through catalyst poisoning or equipment damage; technologies being developed to remove heteroatom impurities are discussed. Alternative technologies to utilize waste fluids, such as a propulsion option called the resistojet, are discussed. The resistojet is an electric propulsion technology with a powered thruster to vaporize and heat a propellant to high temperature, hot gases are subsequently passed through a converging-diverging nozzle expanding gases to supersonic velocities. A resistojet can accommodate many different fluids, including various reaction chamber (by-)products.

Green Aerospace Fuels from Nonpetroleum Sources

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Kulis, Michael J.; DeLaRee, Ana B.; Zubrin, Robert; Berggren, Mark; Hensel, Joseph D.; Kimble, Michael C.

2011-01-01

Efforts to produce green aerospace propellants from nonpetroleum sources are outlined. The paper begins with an overview of feedstock processing and relevant small molecule or C1 chemistry. Gas-to-liquid technologies, notably Fischer-Tropsch (FT) processing of synthesis gas (CO and H2), are being optimized to enhance the fraction of product stream relevant to aviation (and other transportation) fuels at the NASA Glenn Research Center (GRC). Efforts to produce optimized catalysts are described. Given the high cost of space launch, the recycling of human metabolic and plastic wastes to reduce the need to transport consumables to orbit to support the crew of a space station has long been recognized as a high priority. If the much larger costs of transporting consumables to the Moon or beyond are taken into account, the importance of developing waste recycling systems becomes still more imperative. One promising way to transform organic waste products into useful gases is steam reformation; this well-known technology is currently being optimized by a Colorado company for exploration and planetary surface operations. Reduction of terrestrial waste streams while producing energy and/or valuable raw materials is an opportunity being realized by a new generation of visionary entrepreneurs. A technology that has successfully demonstrated production of fuels and related chemicals from waste plastics developed in Northeast Ohio is described. Technologies being developed by a Massachusetts company to remove sulfur impurities are highlighted. Common issues and concerns for nonpetroleum fuel production are emphasized. Energy utilization is a concern for production of fuels whether a terrestrial operation or on the lunar (or Martian) surface; the term green relates to not only mitigating excess carbon release but also to the efficiency of grid-energy usage. For space exploration, energy efficiency can be an essential concern. Other issues of great concern include minimizing impurities in the product stream(s), especially those that potential health risks and/or could degrade operations through catalyst poisoning or equipment damage. The potential impacts on future missions by such concerns are addressed in closing.

Sci-Thur PM – Brachytherapy 01: Fast brachytherapy dose calculations: Characterization of egs-brachy features to enhance simulation efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chamberland, Marc; Taylor, Randle E.P.; Rogers, Da

2016-08-15

Purpose: egs-brachy is a fast, new EGSnrc user-code for brachytherapy applications. This study characterizes egs-brachy features that enhance simulation efficiency. Methods: Calculations are performed to characterize efficiency gains from various features. Simulations include radionuclide and miniature x-ray tube sources in water phantoms and idealized prostate, breast, and eye plaque treatments. Features characterized include voxel indexing of sources to reduce boundary checks during radiation transport, scoring collision kerma via tracklength estimator, recycling photons emitted from sources, and using phase space data to initiate simulations. Bremsstrahlung cross section enhancement (BCSE), uniform bremsstrahlung splitting (UBS), and Russian Roulette (RR) are considered for electronicmore » brachytherapy. Results: Efficiency is enhanced by a factor of up to 300 using tracklength versus interaction scoring of collision kerma and by up to 2.7 and 2.6 using phase space sources and particle recycling respectively compared to simulations in which particles are initiated within sources. On a single 2.5 GHz Intel Xeon E5-2680 processor cor, simulations approximating prostate and breast permanent implant ((2 mm){sup 3} voxels) and eye plaque ((1 mm){sup 3}) treatments take as little as 9 s (prostate, eye) and up to 31 s (breast) to achieve 2% statistical uncertainty on doses within the PTV. For electronic brachytherapy, BCSE, UBS, and RR enhance efficiency by a factor >2000 compared to a factor of >10{sup 4} using a phase space source. Conclusion: egs-brachy features provide substantial efficiency gains, resulting in calculation times sufficiently fast for full Monte Carlo simulations for routine brachytherapy treatment planning.« less

Thermal Considerations of Space Solar Power Concepts with 3.5 GW RF Output

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2000-01-01

This paper presents the thermal challenge of the Space Solar Power (SSP) design concepts with a 3.5 GW radio-frequency (RF) output. High efficiency klystrons are thermally more favored than solid state (butterstick) to convert direct current (DC) electricity to radio-frequency (RF) energy at the transmitters in these concepts. Using klystrons, the heat dissipation is 0.72 GW. Using solid state, the heat dissipation is 2.33 GW. The heat dissipation of the klystrons is 85% at 500C, 10% at 300C, and 5% at 125C. All the heat dissipation of the solid state is at 100C. Using klystrons, the radiator area is 74,500 square m Using solid state, the radiator area is 2,362,200 square m Space constructable heat pipe radiators are assumed in the thermal analysis. Also, to make the SSP concepts feasible, the mass of the heat transport system must be minimized. The heat transport distance from the transmitters to the radiators must be minimized. It can be accomplished by dividing the radiator into a cluster of small radiators, so that the heat transport distances between the klystrons and radiators can be minimized. The area of each small radiator is on the order of 1 square m. Two concepts for accommodating a cluster of small radiators are presented. If the distance between the transmitters and radiators is 1.5 m or less, constant conductance heat pipes (CCHPs) are acceptable for heat transport. If the distance exceeds 1.5 m, loop heat pipes (LHPs) are needed.

Validation of a multi-layer Green's function code for ion beam transport

NASA Astrophysics Data System (ADS)

Walker, Steven; Tweed, John; Tripathi, Ram; Badavi, Francis F.; Miller, Jack; Zeitlin, Cary; Heilbronn, Lawrence

To meet the challenge of future deep space programs, an accurate and efficient engineering code for analyzing the shielding requirements against high-energy galactic heavy radiations is needed. In consequence, a new version of the HZETRN code capable of simulating high charge and energy (HZE) ions with either laboratory or space boundary conditions is currently under development. The new code, GRNTRN, is based on a Green's function approach to the solution of Boltzmann's transport equation and like its predecessor is deterministic in nature. The computational model consists of the lowest order asymptotic approximation followed by a Neumann series expansion with non-perturbative corrections. The physical description includes energy loss with straggling, nuclear attenuation, nuclear fragmentation with energy dispersion and down shift. Code validation in the laboratory environment is addressed by showing that GRNTRN accurately predicts energy loss spectra as measured by solid-state detectors in ion beam experiments with multi-layer targets. In order to validate the code with space boundary conditions, measured particle fluences are propagated through several thicknesses of shielding using both GRNTRN and the current version of HZETRN. The excellent agreement obtained indicates that GRNTRN accurately models the propagation of HZE ions in the space environment as well as in laboratory settings and also provides verification of the HZETRN propagator.

Is bigger always better? An economic study of U.S. ETO vehicle architectures

NASA Technical Reports Server (NTRS)

Eimers, Dan R.; Kakazu, Karen L.

1991-01-01

This analysis, performed as part of NASA's Space Transportation Infrastructure Study, compares the cost efficiency of two candidate launch vehicle families, used in conjunction with existing expendable launch vehicles and the Shuttle, to accomplish the nation's future space missions through 2030. Missions analyzed include those identified in NASA's Civil Needs Data Base (CNDB) and Space Exploration Initiative (SEI) Option E program, as well as estimates of commercial and U.S. Department of Defense flights. A family of Shuttle-derived In-line vehicles is compared against a family designed around a vehicle optimized for large (250t) payloads. The analysis is performed within the context of an entire space transportation architecture. The goal is to determine which architecture best captures the required missions most cost-effectively. Results indicate that, for the particular mission model analyzed, neither option is clearly superior across the entire payload range. The Shuttle-derived family displays a better evolutionary path for supporting the total mission model (CNDB plus SEI missions). It also reduces earth-to-orbit (ETO) peak funding by 20 percent. The architecture incorporating the Heavy Lift ETO family minimizes SEI program cost and on-orbit operations but is subject to greater schedule risk because of the need for concurrent ETO core and engine development.

76 FR 67018 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-28

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

77 FR 35102 - Commercial Space Transportation Advisory Committee; Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-12

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

78 FR 53496 - Commercial Space Transportation Advisory Committee; Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

75 FR 38866 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

75 FR 52058 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-24

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee-Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section 10...

76 FR 4743 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

76 FR 15041 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-18

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

77 FR 48585 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-14

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

75 FR 51332 - Commercial Space Transportation Advisory Committee-Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee--Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

78 FR 14401 - Commercial Space Transportation Advisory Committee; Public Teleconference

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-05

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation Advisory Committee; Public Teleconference AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of Commercial Space Transportation Advisory Committee Teleconference. SUMMARY: Pursuant to Section...

The Ultimate Spitzer Phase Curve Survey

NASA Astrophysics Data System (ADS)

Stevenson, Kevin; Bean, Jacob; Deming, Drake; Desert, Jean-Michel; Feng, Y. Katherina; Fortney, Jonathan; Kataria, Tiffany; Kempton, Eliza; Lewis, Nikole; Line, Michael; Morley, Caroline; Rauscher, Emily; Showman, Adam

2016-08-01

Exoplanet phase curves are sure to be one of the main enduring legacies of Spitzer. They provide a wealth of information about exoplanet atmospheres, including longitudinal constraints on atmospheric composition, thermal structure, and energy transport, that will continue to open new doors of scientific inquiry and propel future investigations for years to come. The measured heat redistribution efficiency (or ability to transport energy from a planet's highly-irradiated dayside to its eternally-dark nightside) shows considerable variation between exoplanets. Theoretical models predict a correlation between heat redistribution efficiency and planet temperature; however, the latest results are inconsistent with current predictions. Instead, a new potential trend is emerging, one that connects heat redistribution efficiency with planet rotation rate. We will test this hypothesis by performing Spitzer phase curve observations of seven exoplanets with physical properties that span the parameter space. We have identified high-contrast targets with short orbital periods around bright host stars to ensure the observations reveal robust phase curve results. Spitzer is uniquely suited for this program because we can achieve our primary goals using broadband photometry. Part of the phase curve legacy will be to combine our archived Spitzer data with transmission and dayside emission spectra from HST and JWST. Adding energy transport and cloud coverage constraints to the measured dayside abundances and thermal profiles will yield a fundamental understanding of these exoplanets' atmospheres that can be leveraged into new avenues of investigation.

Fluid dilution and efficiency of Na(+) transport in a mathematical model of a thick ascending limb cell.

PubMed

Nieves-González, Aniel; Clausen, Chris; Marcano, Mariano; Layton, Anita T; Layton, Harold E; Moore, Leon C

2013-03-15

Thick ascending limb (TAL) cells are capable of reducing tubular fluid Na(+) concentration to as low as ~25 mM, and yet they are thought to transport Na(+) efficiently owing to passive paracellular Na(+) absorption. Transport efficiency in the TAL is of particular importance in the outer medulla where O(2) availability is limited by low blood flow. We used a mathematical model of a TAL cell to estimate the efficiency of Na(+) transport and to examine how tubular dilution and cell volume regulation influence transport efficiency. The TAL cell model represents 13 major solutes and the associated transporters and channels; model equations are based on mass conservation and electroneutrality constraints. We analyzed TAL transport in cells with conditions relevant to the inner stripe of the outer medulla, the cortico-medullary junction, and the distal cortical TAL. At each location Na(+) transport efficiency was computed as functions of changes in luminal NaCl concentration ([NaCl]), [K(+)], [NH(4)(+)], junctional Na(+) permeability, and apical K(+) permeability. Na(+) transport efficiency was calculated as the ratio of total net Na(+) transport to transcellular Na(+) transport. Transport efficiency is predicted to be highest at the cortico-medullary boundary where the transepithelial Na(+) gradient is the smallest. Transport efficiency is lowest in the cortex where luminal [NaCl] approaches static head.

Advanced electrical power, distribution and control for the Space Transportation System

NASA Astrophysics Data System (ADS)

Hansen, Irving G.; Brandhorst, Henry W., Jr.

1990-08-01

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems.

Advanced electrical power, distribution and control for the Space Transportation System

NASA Technical Reports Server (NTRS)

Hansen, Irving G.; Brandhorst, Henry W., Jr.

1990-01-01

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems.

Future Space Transportation Technology: Prospects and Priorities

NASA Technical Reports Server (NTRS)

Billie, Matt; Reed, Lisa; Harris, David

2003-01-01

The Transportation Working Group (TWG) was chartered by the NASA Exploration Team (NEXT) to conceptualize, define, and advocate within NASA the space transportation architectures and technologies required to enable the human and robotic exploration and development of space envisioned by the NEXT. In 2002, the NEXT tasked the TWG to assess exploration space transportation requirements versus current and prospective Earth-to-Orbit (ETO) and in-space transportation systems, technologies, and research, in order to identify investment gaps and recommend priorities. The result was a study now being incorporated into future planning by the NASA Space Architect and supporting organizations. This paper documents the process used to identify exploration space transportation investment gaps, as well as the group's recommendations for closing these gaps and prioritizing areas of future investment for NASA work on advanced propulsion systems.

Alternative Suspension System for Space Shuttle Avionics Shelf

NASA Technical Reports Server (NTRS)

Biele, Frank H., III

2010-01-01

Engineers working in the Aerospace field under deadlines and strict budgets often miss the opportunity to design something that is considered new or innovative, favoring instead to use the tried-and-true design over those that may, in fact, be more efficient. This thesis examines an electronic equipment stowage shelf suspended from a frame in the cargo bay (mid fuselage) of the United States Space Transportation System (STS), the Space Shuttle, and 3 alternative designs. Four different designs are examined and evaluated. The first design is a conventional truss, representing the tried and true approach. The second is a cable dome type structure consisting of struts and pre-stressed wiring. The third and fourth are double layer tensegrity systems consisting of contiguous struts of the order k=1 and k=2 respectively.

Space Bioreactor Science Workshop

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Editor)

1987-01-01

The first space bioreactor has been designed for microprocessor control, no gaseous headspace, circulation and resupply of culture medium, and a slow mixing in very low shear regimes. Various ground based bioreactors are being used to test reactor vessel design, on-line sensors, effects of shear, nutrient supply, and waste removal from continuous culture of human cells attached to microcarriers. The small (500 ml) bioreactor is being constructed for flight experiments in the Shuttle middeck to verify systems operation under microgravity conditions and to measure the efficiencies of mass transport, gas transfer, oxygen consumption, and control of low shear stress on cells. Applications of microcarrier cultures, development of the first space bioreactor flight system, shear and mixing effects on cells, process control, and methods to monitor cell metabolism and nutrient requirements are among the topics covered.

Research Technology

NASA Image and Video Library

1997-02-01

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. This photograph shows components for the thermal propulsion engine being laid out prior to assembly. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

Direct Imaging of Exciton Transport in Tubular Porphyrin Aggregates by Ultrafast Microscopy.

PubMed

Wan, Yan; Stradomska, Anna; Knoester, Jasper; Huang, Libai

2017-05-31

Long-range exciton transport is a key challenge in achieving efficient solar energy harvesting in both organic solar cells and photosynthetic systems. Self-assembled molecular aggregates provide the potential for attaining long-range exciton transport through strong intermolecular coupling. However, there currently lacks an experimental tool to directly characterize exciton transport in space and in time to elucidate mechanisms. Here we report a direct visualization of exciton diffusion in tubular molecular aggregates by transient absorption microscopy with ∼200 fs time resolution and ∼50 nm spatial precision. These direct measurements provide exciton diffusion constants of 3-6 cm 2 s -1 for the tubular molecular aggregates, which are 3-5 times higher than a theoretical lower bound obtained by assuming incoherent hopping. These results suggest that coherent effects play a role, despite the fact that exciton states near the band bottom crucial for transport are only weakly delocalized (over <10 molecules). The methods presented here establish a direct approach for unraveling the mechanisms and main parameters underlying exciton transport in large molecular assemblies.

Effects of Space Flight, Clinorotation, and Centrifugation on the Growth and Metabolism of Escherichia Coli

NASA Technical Reports Server (NTRS)

Brown, Robert B.

1999-01-01

Previous experiments have shown that space flight stimulates bacterial growth and metabolism. An explanation for these results is proposed, which may eventually lead to improved terrestrial pharmaceutical production efficiency. It is hypothesized that inertial acceleration affects bacterial growth and metabolism by altering the transport phenomena in the cells external fluid environment. It is believed that this occurs indirectly through changes in the sedimentation rate acting on the bacteria and buoyancy-driven convection acting on their excreted by-products. Experiments over a broad range of accelerations consistently supported this theory. Experiments at I g indicated that higher concentrations of excreted by products surrounding bacterial cells result in a shorter lag phase. Nineteen additional experiments simulated 0 g and 0.5 g using a clinostat, and achieved 50 g, 180 g, and 400 g using a centrifuge. These experiments showed that final cell density is inversely related to the level of acceleration. The experiments also consistently showed that acceleration affects the length of the lag phase in a non-monotonic, yet predictable, manner. Additional data indicated that E. coli metabolize glucose less efficiently at hypergravity, and more efficiently at hypogravity. A space-flight experiment was also performed. Samples on orbit had a statistically significant higher final cell density and more efficient metabolism than did ground controls. These results. which were similar to simulations of 0 g using a clinostat, support the theory that gravity only affects bacterial growth and metabolism indirectly, through changes in the bacteria's fluid environment.

Hybrid Power Management Program Evaluated Ultracapacitors for the Next Generation Launch Transportation Project

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2005-01-01

The NASA Glenn Research Center initiated baseline testing of ultracapacitors to obtain empirical data in determining the feasibility of using ultracapacitors for the Next Generation Launch Transportation (NGLT) Project. There are large transient loads associated with NGLT that require a very large primary energy source or an energy storage system. The primary power source used for this test was a proton-exchange-membrane (PEM) fuel cell. The energy storage system can consist of batteries, flywheels, or ultracapacitors. Ultracapacitors were used for these tests. NASA Glenn has a wealth of experience in ultracapacitor technology through the Hybrid Power Management (HPM) Program, which the Avionics, Power and Communications Branch of Glenn s Engineering Development Division initiated for the Technology Transfer and Partnership Office. HPM is the innovative integration of diverse, state-ofthe- art power devices in optimal configurations for space and terrestrial applications. The appropriate application and control of the various advanced power devices (such as ultracapacitors and fuel cells) significantly improves overall system performance and efficiency. HPM has extremely wide potential. Applications include power generation, transportation systems, biotechnology systems, and space power systems. HPM has the potential to significantly alleviate global energy concerns, improve the environment, and stimulate the economy.

The Space Shuttle - A future space transportation system

NASA Technical Reports Server (NTRS)

Thompson, R. F.

1974-01-01

The objective of the Space Shuttle Program is to achieve an economical space transportation system. This paper provides an introductory review of the considerations which led to the Government decisions to develop the Space Shuttle. The role of a space transportation system is then considered within the context of historical developments in the general field of transportation, followed by a review of the Shuttle system, mission profile, payload categories, and payload accommodations which the Shuttle system will provide, and concludes with a forecast of the systems utilization for space science research and payload planning activity.

Approaches in the determination of plant nutrient uptake and distribution in space flight conditions

NASA Technical Reports Server (NTRS)

Heyenga, A. G.; Forsman, A.; Stodieck, L. S.; Hoehn, A.; Kliss, M.

2000-01-01

The effective growth and development of vascular plants rely on the adequate availability of water and nutrients. Inefficiency in either the initial absorption, transportation, or distribution of these elements are factors which impinge on plant structure and metabolic integrity. The potential effect of space flight and microgravity conditions on the efficiency of these processes is unclear. Limitations in the available quantity of space-grown plant material and the sensitivity of routine analytical techniques have made an evaluation of these processes impractical. However, the recent introduction of new plant cultivating methodologies supporting the application of radionuclide elements and subsequent autoradiography techniques provides a highly sensitive investigative approach amenable to space flight studies. Experiments involving the use of gel based 'nutrient packs' and the radionuclides calcium-45 and iron-59 were conducted on the Shuttle mission STS-94. Uptake rates of the radionuclides between ground and flight plant material appeared comparable.

Approaches in the Determination of Plant Nutrient Uptake and Distribution in Space Flight Conditions

NASA Technical Reports Server (NTRS)

Heyenga, A. G.; Forsman, A.; Stodieck, L. S.; Hoehn, A.; Kliss, Mark

1998-01-01

The effective growth and development of vascular plants rely on the adequate availability of water and nutrients. Inefficiency in either the initial absorption, transportation, or distribution of these elements are factors which may impinge on plant structure and metabolic integrity. The potential effect of space flight and microgravity conditions on the efficiency of these processes is unclear. Limitations in the available quantity of space-grown plant material and the sensitivity of routine analytical techniques have made an evaluation of these processes impractical. However, the recent introduction of new plant cultivating methodologies supporting the application of radionuclide elements and subsequent autoradiography techniques provides a highly sensitive investigative approach amenable to space flight studies. Experiments involving the use of gel based 'nutrient packs' and the nuclides Ca45 and Fe59 were conducted on the Shuttle mission STS-94. Uptake rates of the radionuclides between ground and flight plant material appeared comparable.

Urban simulation evaluation with study case of the Singapore Management University, Singapore

NASA Astrophysics Data System (ADS)

Seanders, O.

2018-01-01

This paper reports and discusses about the urban simulation evaluation with a study case, The Singapore Managemant University (SMU), the first major university to be located in the city centre. It is located in Bras Basah District, with some controversy on the geographical establishment, the physical realization of the University in the original plan required some demolishes, urban historical building, a public park and in the end will impact the lose of some certain qualities of the urban space. From this case we can see that the urban design and cultural heritage principles could come into conflicts with the more practical concerns of space constraints and transportation efficiency. This SMU case reflect the problem of the developing countries that have to decide between conservation of buildings and green spaces and space demands. In this case, for Singapore, it marks a progress in the step of greater community involvement in the planning process.

Kennedy Space Center - "America's Gateway to Space"

NASA Technical Reports Server (NTRS)

Petro, Janet; Chevalier, Mary Ann; Hurst, Chery

2011-01-01

KSC fits into the overall NASA vision and mission by moving forward so that what we do and learn will benefit all here on Earth. In January of last year, KSC revised its Mission and Vision statements to articulate our identity as we align with this new direction the Agency is heading. Currently KSC is endeavoring to form partnerships with industry, , Government, and academia, utilizing institutional assets and technical capabilities to support current and future m!issions. With a goal of safe, low-cost, and readily available access to space, KSC seeks to leverage emerging industries to initiate development of a new space launch system, oversee the development of a multipurpose crew vehicle, and assist with the efficient and timely evolution of commercial crew transportation capabilities. At the same time, KSC is pursuing modernizing the Center's infrastructure and creating a multi-user launch complex with increased onsite processing and integration capabilities.

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

Astronaut Mike Fincke, a former commander of the International Space Station, speaks during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida, speaks during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Aircraft energy efficiency laminar flow control glove flight conceptual design study

NASA Technical Reports Server (NTRS)

Wright, A. S.

1979-01-01

A laminar flow control glove applied to the wing of a short to medium range jet transport with aft mounted engines was designed. A slotted aluminum glove concept and a woven stainless steel mesh porous glove concept suction surfaces were studied. The laminar flow control glove and a dummy glove with a modified supercritical airfoil, ducting, modified wing leading and trailing edges, modified flaps, and an LFC trim tab were applied to the wing after slot spacing suction parameters, and compression power were determined. The results show that a laminar flow control glove can be applied to the wing of a jet transport with an appropriate suction system installed.

TAE Plus: Transportable Applications Environment Plus tools for building graphic-oriented applications

NASA Technical Reports Server (NTRS)

Szczur, Martha R.

1989-01-01

The Transportable Applications Environment Plus (TAE Plus), developed by NASA's Goddard Space Flight Center, is a portable User Interface Management System (UIMS), which provides an intuitive WYSIWYG WorkBench for prototyping and designing an application's user interface, integrated with tools for efficiently implementing the designed user interface and effective management of the user interface during an application's active domain. During the development of TAE Plus, many design and implementation decisions were based on the state-of-the-art within graphics workstations, windowing system and object-oriented programming languages. Some of the problems and issues experienced during implementation are discussed. A description of the next development steps planned for TAE Plus is also given.

High-voltage Array Ground Test for Direct-drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Mankins, John C.; O'Neill, Mark J.

2005-01-01

Development is underway on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for direct drive electric propulsion. These SLA performance attributes closely match the critical needs of solar electric propulsion (SEP) systems, which may be used for "space tugs" to fuel-efficiently transport cargo from low earth orbit (LEO) to low lunar orbit (LLO), in support of NASA s robotic and human exploration missions. Later SEP systems may similarly transport cargo from the earth-moon neighborhood to the Mars neighborhood. This paper will describe the SLA SEP technology, discuss ground tests already completed, and present plans for future ground tests and future flight tests of SLA SEP systems.

High-Voltage High-Energy Stretched Lens Array Square-Rigger (SLASR) for Direct-Drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Howell, Joe T.; O'Neill, Mark J.; Mankins, John C.

2006-01-01

Development is underway on a unique high-voltage, high energy solar concentrator array called Stretched Lens Array Square-Rigger (SLASR) for direct drive electric propulsion. The SLASR performance attributes closely match the critical needs of solar electric propulsion (SEP) systems, which may be used for space tugs to fuel efficiently transport cargo from low earth orbit (LEO) to low lunar orbit (LLO), in support of NASA's robotic and human exploration missions. Later SEP systems may similarly transport cargo from the earth-moon neighborhood to the Mars neighborhood. This paper will describe the SLASR technology, discuss SLASR developments and ground testing, and outline plans for future SLASR technology maturation.

High-Voltage High-Energy Stretched Lens Array Square-Rigger (SLASR) for Direct-Drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Howell, Joe T.; O'Neill, Mark; Mankins, John C.

2006-01-01

Development is underway on a unique high-voltage, high-energy solar concentrator array called Stretched Lens Array Square-Rigger (SLASR) for direct drive electric propulsion. The SLASR performance attributes closely match the critical needs of solar electric propulsion (SEP) systems, which may be used for space tugs to fuel-efficiently transport cargo from low earth orbit (LEO) to low lunar orbit (LLO), in support of NASA s robotic and human exploration missions. Later SEP systems may similarly transport cargo from the earth-moon neighborhood to the Mars neighborhood. This paper will describe the SLASR technology, discuss SLASR developments and ground testing, and outline plans for future SLASR technology maturation.

Concentration polarization-based nonlinear electrokinetics in porous media: induced-charge electroosmosis.

PubMed

Leinweber, Felix C; Tallarek, Ulrich

2005-11-24

We have investigated induced-charge electroosmotic flow in a fixed bed of ion-permselective glass beads by quantitative confocal laser scanning microscopy. Externally applied electrical fields induce concentration polarization (CP) in the porous medium due to coupled mass and charge transport normal to the charge-selective interfaces. These data reveal the generation of a nonequilibrium electrical double layer in the depleted CP zones and the adjoining anodic hemispheres of the (cation-selective) glass beads above a critical field strength. This initiates CP-based induced-charge electroosmosis along curved interfaces of the quasi-electroneutral macropore space between glass beads. Caused by mutual interference of resulting nonlinear flow with (flow-inducing) space charge regions, an electrohydrodynamic instability can appear locally and realize turbulent flow behavior at low Reynolds numbers. It is characterized by a local destruction of the CP zones and concomitant removal of diffusion-limited mass transfer. More efficient pore-scale lateral mixing also improves macroscopic transport, which is reflected in the significantly reduced axial dispersion of a passive tracer.

Recent Progress in the Development of a Multi-Layer Green's Function Code for Ion Beam Transport

NASA Technical Reports Server (NTRS)

Tweed, John; Walker, Steven A.; Wilson, John W.; Tripathi, Ram K.

2008-01-01

To meet the challenge of future deep space programs, an accurate and efficient engineering code for analyzing the shielding requirements against high-energy galactic heavy radiation is needed. To address this need, a new Green's function code capable of simulating high charge and energy ions with either laboratory or space boundary conditions is currently under development. The computational model consists of combinations of physical perturbation expansions based on the scales of atomic interaction, multiple scattering, and nuclear reactive processes with use of the Neumann-asymptotic expansions with non-perturbative corrections. The code contains energy loss due to straggling, nuclear attenuation, nuclear fragmentation with energy dispersion and downshifts. Previous reports show that the new code accurately models the transport of ion beams through a single slab of material. Current research efforts are focused on enabling the code to handle multiple layers of material and the present paper reports on progress made towards that end.

Interplay between efficiency and device architecture for small molecule organic solar cells.

PubMed

Williams, Graeme; Sutty, Sibi; Aziz, Hany

2014-06-21

Small molecule organic solar cells (OSCs) have experienced a resurgence of interest over their polymer solar cell counterparts, owing to their improved batch-to-batch (thus, cell-to-cell) reliability. In this systematic study on OSC device architecture, we investigate five different small molecule OSC structures, including the simple planar heterojunction (PHJ) and bulk heterojunction (BHJ), as well as several planar-mixed structures. The different OSC structures are studied over a wide range of donor:acceptor mixing concentrations to gain a comprehensive understanding of their charge transport behavior. Transient photocurrent decay measurements provide crucial information regarding the interplay between charge sweep-out and charge recombination, and ultimately hint toward space charge effects in planar-mixed structures. Results show that the BHJ/acceptor architecture, comprising a BHJ layer with high C60 acceptor content, generates OSCs with the highest performance by balancing charge generation with charge collection. The performance of other device architectures is largely limited by hole transport, with associated hole accumulation and space charge effects.

Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

PubMed

Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

2015-06-01

This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduced discretization error in HZETRN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slaba, Tony C., E-mail: Tony.C.Slaba@nasa.gov; Blattnig, Steve R., E-mail: Steve.R.Blattnig@nasa.gov; Tweed, John, E-mail: jtweed@odu.edu

2013-02-01

The deterministic particle transport code HZETRN is an efficient analysis tool for studying the effects of space radiation on humans, electronics, and shielding materials. In a previous work, numerical methods in the code were reviewed, and new methods were developed that further improved efficiency and reduced overall discretization error. It was also shown that the remaining discretization error could be attributed to low energy light ions (A < 4) with residual ranges smaller than the physical step-size taken by the code. Accurately resolving the spectrum of low energy light particles is important in assessing risk associated with astronaut radiation exposure.more » In this work, modifications to the light particle transport formalism are presented that accurately resolve the spectrum of low energy light ion target fragments. The modified formalism is shown to significantly reduce overall discretization error and allows a physical approximation to be removed. For typical step-sizes and energy grids used in HZETRN, discretization errors for the revised light particle transport algorithms are shown to be less than 4% for aluminum and water shielding thicknesses as large as 100 g/cm{sup 2} exposed to both solar particle event and galactic cosmic ray environments.« less

Systematic Dimensionality Reduction for Quantum Walks: Optimal Spatial Search and Transport on Non-Regular Graphs

PubMed Central

Novo, Leonardo; Chakraborty, Shantanav; Mohseni, Masoud; Neven, Hartmut; Omar, Yasser

2015-01-01

Continuous time quantum walks provide an important framework for designing new algorithms and modelling quantum transport and state transfer problems. Often, the graph representing the structure of a problem contains certain symmetries that confine the dynamics to a smaller subspace of the full Hilbert space. In this work, we use invariant subspace methods, that can be computed systematically using the Lanczos algorithm, to obtain the reduced set of states that encompass the dynamics of the problem at hand without the specific knowledge of underlying symmetries. First, we apply this method to obtain new instances of graphs where the spatial quantum search algorithm is optimal: complete graphs with broken links and complete bipartite graphs, in particular, the star graph. These examples show that regularity and high-connectivity are not needed to achieve optimal spatial search. We also show that this method considerably simplifies the calculation of quantum transport efficiencies. Furthermore, we observe improved efficiencies by removing a few links from highly symmetric graphs. Finally, we show that this reduction method also allows us to obtain an upper bound for the fidelity of a single qubit transfer on an XY spin network. PMID:26330082

75 FR 45196 - Office of Commercial Space Transportation; Notice of Availability of the Final Supplemental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-02

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Office of Commercial Space..., the FAA would issue a Launch Site Operator License to Space Florida to operate a commercial space... of Commercial Space Transportation Web site at http://www.faa.gov/about/office_org/headquarters...

Generalized reference fields and source interpolation for the difference formulation of radiation transport

NASA Astrophysics Data System (ADS)

Luu, Thomas; Brooks, Eugene D.; Szőke, Abraham

2010-03-01

In the difference formulation for the transport of thermally emitted photons the photon intensity is defined relative to a reference field, the black body at the local material temperature. This choice of reference field combines the separate emission and absorption terms that nearly cancel, thereby removing the dominant cause of noise in the Monte Carlo solution of thick systems, but introduces time and space derivative source terms that cannot be determined until the end of the time step. The space derivative source term can also lead to noise induced crashes under certain conditions where the real physical photon intensity differs strongly from a black body at the local material temperature. In this paper, we consider a difference formulation relative to the material temperature at the beginning of the time step, or in cases where an alternative temperature better describes the radiation field, that temperature. The result is a method where iterative solution of the material energy equation is efficient and noise induced crashes are avoided. We couple our generalized reference field scheme with an ad hoc interpolation of the space derivative source, resulting in an algorithm that produces the correct flux between zones as the physical system approaches the thick limit.

An ultra-thin, un-doped NiO hole transporting layer of highly efficient (16.4%) organic-inorganic hybrid perovskite solar cells.

PubMed

Seo, Seongrok; Park, Ik Jae; Kim, Myungjun; Lee, Seonhee; Bae, Changdeuck; Jung, Hyun Suk; Park, Nam-Gyu; Kim, Jin Young; Shin, Hyunjung

2016-06-02

NiO is a wide band gap p-type oxide semiconductor and has potential for applications in solar energy conversion as a hole-transporting layer (HTL). It also has good optical transparency and high chemical stability, and the capability of aligning the band edges to the perovskite (CH3NH3PbI3) layers. Ultra-thin and un-doped NiO films with much less absorption loss were prepared by atomic layer deposition (ALD) with highly precise control over thickness without any pinholes. Thin enough (5-7.5 nm in thickness) NiO films with the thickness of few time the Debye length (LD = 1-2 nm for NiO) show enough conductivities achieved by overlapping space charge regions. The inverted planar perovskite solar cells with NiO films as HTLs exhibited the highest energy conversion efficiency of 16.40% with high open circuit voltage (1.04 V) and fill factor (0.72) with negligible current-voltage hysteresis.

14 CFR 404.1 - Scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... requirements for licensing or permitting of commercial space transportation activities under that statute. [Doc... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Scope. 404.1 Section 404.1 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

NASA Administrator Charles Bolden, left, announces the agency’s selection of Boeing and SpaceX to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft as Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida looks on at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

NASA Propulsion Engineering Research Center, volume 1

NASA Technical Reports Server (NTRS)

1993-01-01

Over the past year, the Propulsion Engineering Research Center at The Pennsylvania State University continued its progress toward meeting the goals of NASA's University Space Engineering Research Centers (USERC) program. The USERC program was initiated in 1988 by the Office of Aeronautics and Space Technology to provide an invigorating force to drive technology advancements in the U.S. space industry. The Propulsion Center's role in this effort is to provide a fundamental basis from which the technology advances in propulsion can be derived. To fulfill this role, an integrated program was developed that focuses research efforts on key technical areas, provides students with a broad education in traditional propulsion-related science and engineering disciplines, and provides minority and other under-represented students with opportunities to take their first step toward professional careers in propulsion engineering. The program is made efficient by incorporating government propulsion laboratories and the U.S. propulsion industry into the program through extensive interactions and research involvement. The Center is comprised of faculty, professional staff, and graduate and undergraduate students working on a broad spectrum of research issues related to propulsion. The Center's research focus encompasses both current and advanced propulsion concepts for space transportation, with a research emphasis on liquid propellant rocket engines. The liquid rocket engine research includes programs in combustion and turbomachinery. Other space transportation modes that are being addressed include anti-matter, electric, nuclear, and solid propellant propulsion. Outside funding supports a significant fraction of Center research, with the major portion of the basic USERC grant being used for graduate student support and recruitment. The remainder of the USERC funds are used to support programs to increase minority student enrollment in engineering, to maintain Center infrastructure, and to develop research capability in key new areas. Significant research programs in propulsion systems for air and land transportation complement the space propulsion focus. The primary mission of the Center is student education. The student program emphasizes formal class work and research in classical engineering and science disciplines with applications to propulsion.

NASA's Spaceliner Investment Area Technology Activities

NASA Technical Reports Server (NTRS)

Hueter, Uwe; Lyles, Garry M. (Technical Monitor)

2001-01-01

NASA's has established long term goals for access-to-space. The third generation launch systems are to be fully reusable and operational around 2025. The goals for the third generation launch system are to significantly reduce cost and improve safety over current conditions. The Advanced Space Transportation Program Office (ASTP) at the NASA's Marshall Space Flight Center in Huntsville, AL has the agency lead to develop space transportation technologies. Within ASTP, under the Spaceliner Investment Area, third generation technologies are being pursued in the areas of propulsion, airframes, integrated vehicle health management (IVHM), avionics, power, operations, and range. The ASTP program will mature these technologies through both ground and flight system testing. The Spaceliner Investment Area plans to mature vehicle technologies to reduce the implementation risks for future commercially developed reusable launch vehicles (RLV). The plan is to substantially increase the design and operating margins of the third generation RLV (the Space Shuttle is the first generation) by incorporating advanced technologies in propulsion, materials, structures, thermal protection systems, avionics, and power. Advancements in design tools and better characterization of the operational environment will allow improvements in design margins. Improvements in operational efficiencies will be provided through use of advanced integrated health management, operations, and range technologies. The increase in margins will allow components to operate well below their design points resulting in improved component operating life, reliability, and safety which in turn reduces both maintenance and refurbishment costs. These technologies have the potential of enabling horizontal takeoff by reducing the takeoff weight and achieving the goal of airline-like operation. These factors in conjunction with increased flight rates from an expanding market will result in significant improvements in safety and reductions in operational costs of future vehicles. The paper describes current status, future plans and technologies that are being matured by the Spaceliner Investment Area under the Advanced Space Transportation Program Office.

National Space Transportation Policy: Issues for Congress

NASA Astrophysics Data System (ADS)

1995-05-01

This report, prepared for the House Committee on Science, is the first in a broad assessment of the health and future prospects of the U.S. space transportation technology and industrial base. The report focuses on the Clinton Administration's National Space Transportation Policy, which was released last fall. It examines administration policy in light of the implementation plans prepared by NASA, DOD, and the Transportation and Commerce Departments. The policy also emphasizes the important contribution private industry can make to the direction and development of U.S. space transportation capabilities. However, an analysis of the policy and implementation plans also raises some issues that might be of interest to Congress as it debates space transportation legislation, oversight, and funding. These issues involve decisions on NASA and DOD development programs, the use of foreign launch vehicles, and the new role of the private sector in space transportation research and development decisionmaking. This report also identifies two issues omitted from the Administration's policy: the preservation of long-range ballistic missile capabilities after final production in 2005, and the perspective of lower industrial tier firms toward national space transportation policy.

Low-cost Radon Reduction Pilot Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, William B.; Francisco, Paul W.; Merrin, Zachary

The U.S. Department of Energy's Building America research team Partnership for Advanced Residential Retrofits conducted a primary scoping study on the impact of air sealing between the foundation and the living space on radon transport reduction across the foundation and living space floor assembly. Fifteen homes in the Champaign, Illinois, area participated in the study. These homes were instrumented for hourly continuous radon measurements and simultaneous temperature and humidity measurements. Blower door and zone pressure diagnostics were conducted at each house. The treatments consisted of using air-sealing foams at the underside of the floor that separated the living space frommore » the foundation and providing duct sealing on the ductwork that is situated in the foundation area. The hypothesis was that air sealing the floor system that separated the foundation from the living space should better isolate the living space from the foundation; this isolation should lead to less radon entering the living space from the foundation. If the hypothesis had been proven, retrofit energy-efficiency programs may have chosen to adopt these isolation methods for enhanced radon protection to the living space.« less

The Effect of Body Posture on Brain Glymphatic Transport.

PubMed

Lee, Hedok; Xie, Lulu; Yu, Mei; Kang, Hongyi; Feng, Tian; Deane, Rashid; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

2015-08-05

The glymphatic pathway expedites clearance of waste, including soluble amyloid β (Aβ) from the brain. Transport through this pathway is controlled by the brain's arousal level because, during sleep or anesthesia, the brain's interstitial space volume expands (compared with wakefulness), resulting in faster waste removal. Humans, as well as animals, exhibit different body postures during sleep, which may also affect waste removal. Therefore, not only the level of consciousness, but also body posture, might affect CSF-interstitial fluid (ISF) exchange efficiency. We used dynamic-contrast-enhanced MRI and kinetic modeling to quantify CSF-ISF exchange rates in anesthetized rodents' brains in supine, prone, or lateral positions. To validate the MRI data and to assess specifically the influence of body posture on clearance of Aβ, we used fluorescence microscopy and radioactive tracers, respectively. The analysis showed that glymphatic transport was most efficient in the lateral position compared with the supine or prone positions. In the prone position, in which the rat's head was in the most upright position (mimicking posture during the awake state), transport was characterized by "retention" of the tracer, slower clearance, and more CSF efflux along larger caliber cervical vessels. The optical imaging and radiotracer studies confirmed that glymphatic transport and Aβ clearance were superior in the lateral and supine positions. We propose that the most popular sleep posture (lateral) has evolved to optimize waste removal during sleep and that posture must be considered in diagnostic imaging procedures developed in the future to assess CSF-ISF transport in humans. The rodent brain removes waste better during sleep or anesthesia compared with the awake state. Animals exhibit different body posture during the awake and sleep states, which might affect the brain's waste removal efficiency. We investigated the influence of body posture on brainwide transport of inert tracers of anesthetized rodents. The major finding of our study was that waste, including Aβ, removal was most efficient in the lateral position (compared with the prone position), which mimics the natural resting/sleeping position of rodents. Although our finding awaits testing in humans, we speculate that the lateral position during sleep has advantage with regard to the removal of waste products including Aβ, because clinical studies have shown that sleep drives Aβ clearance from the brain. Copyright © 2015 the authors 0270-6474/15/3511034-11$15.00/0.

The Effect of Body Posture on Brain Glymphatic Transport

PubMed Central

Lee, Hedok; Xie, Lulu; Yu, Mei; Kang, Hongyi; Feng, Tian; Deane, Rashid; Logan, Jean; Nedergaard, Maiken

2015-01-01

The glymphatic pathway expedites clearance of waste, including soluble amyloid β (Aβ) from the brain. Transport through this pathway is controlled by the brain's arousal level because, during sleep or anesthesia, the brain's interstitial space volume expands (compared with wakefulness), resulting in faster waste removal. Humans, as well as animals, exhibit different body postures during sleep, which may also affect waste removal. Therefore, not only the level of consciousness, but also body posture, might affect CSF–interstitial fluid (ISF) exchange efficiency. We used dynamic-contrast-enhanced MRI and kinetic modeling to quantify CSF-ISF exchange rates in anesthetized rodents' brains in supine, prone, or lateral positions. To validate the MRI data and to assess specifically the influence of body posture on clearance of Aβ, we used fluorescence microscopy and radioactive tracers, respectively. The analysis showed that glymphatic transport was most efficient in the lateral position compared with the supine or prone positions. In the prone position, in which the rat's head was in the most upright position (mimicking posture during the awake state), transport was characterized by “retention” of the tracer, slower clearance, and more CSF efflux along larger caliber cervical vessels. The optical imaging and radiotracer studies confirmed that glymphatic transport and Aβ clearance were superior in the lateral and supine positions. We propose that the most popular sleep posture (lateral) has evolved to optimize waste removal during sleep and that posture must be considered in diagnostic imaging procedures developed in the future to assess CSF-ISF transport in humans. SIGNIFICANCE STATEMENT The rodent brain removes waste better during sleep or anesthesia compared with the awake state. Animals exhibit different body posture during the awake and sleep states, which might affect the brain's waste removal efficiency. We investigated the influence of body posture on brainwide transport of inert tracers of anesthetized rodents. The major finding of our study was that waste, including Aβ, removal was most efficient in the lateral position (compared with the prone position), which mimics the natural resting/sleeping position of rodents. Although our finding awaits testing in humans, we speculate that the lateral position during sleep has advantage with regard to the removal of waste products including Aβ, because clinical studies have shown that sleep drives Aβ clearance from the brain. PMID:26245965

Shuttle Safety Improvements

NASA Technical Reports Server (NTRS)

Henderson, Edward

2001-01-01

The Space Shuttle has been flying for over 20 years and based on the Orbiter design life of 100 missions it should be capable of flying at least 20 years more if we take care of it. The Space Shuttle Development Office established in 1997 has identified those upgrades needed to keep the Shuttle flying safely and efficiently until a new reusable launch vehicle (RLV) is available to meet the agency commitments and goals for human access to space. The upgrade requirements shown in figure 1 are to meet the program goals, support HEDS and next generation space transportation goals while protecting the country 's investment in the Space Shuttle. A major review of the shuttle hardware and processes was conducted in 1999 which identified key shuttle safety improvement priorities, as well as other system upgrades needed to reliably continue to support the shuttle miss ions well into the second decade of this century. The high priority safety upgrades selected for development and study will be addressed in this paper.

14 CFR 1260.36 - Travel and transportation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Travel and transportation. 1260.36 Section 1260.36 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Provisions § 1260.36 Travel and transportation. Travel and Transportation October 2000 (a...

14 CFR 1260.36 - Travel and transportation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Travel and transportation. 1260.36 Section 1260.36 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Provisions § 1260.36 Travel and transportation. Travel and Transportation October 2000 (a...

14 CFR 1260.36 - Travel and transportation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Travel and transportation. 1260.36 Section 1260.36 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Provisions § 1260.36 Travel and transportation. Travel and Transportation October 2000 (a...

Efficient Numerical Methods for Nonlinear-Facilitated Transport and Exchange in a Blood-Tissue Exchange Unit

PubMed Central

Poulain, Christophe A.; Finlayson, Bruce A.; Bassingthwaighte, James B.

2010-01-01

The analysis of experimental data obtained by the multiple-indicator method requires complex mathematical models for which capillary blood-tissue exchange (BTEX) units are the building blocks. This study presents a new, nonlinear, two-region, axially distributed, single capillary, BTEX model. A facilitated transporter model is used to describe mass transfer between plasma and intracellular spaces. To provide fast and accurate solutions, numerical techniques suited to nonlinear convection-dominated problems are implemented. These techniques are the random choice method, an explicit Euler-Lagrange scheme, and the MacCormack method with and without flux correction. The accuracy of the numerical techniques is demonstrated, and their efficiencies are compared. The random choice, Euler-Lagrange and plain MacCormack method are the best numerical techniques for BTEX modeling. However, the random choice and Euler-Lagrange methods are preferred over the MacCormack method because they allow for the derivation of a heuristic criterion that makes the numerical methods stable without degrading their efficiency. Numerical solutions are also used to illustrate some nonlinear behaviors of the model and to show how the new BTEX model can be used to estimate parameters from experimental data. PMID:9146808

Space transportation systems within ESA programmes: Current status and perspectives

NASA Astrophysics Data System (ADS)

Delahais, Maurice

1993-03-01

An overview of the space transportation aspects of the ESA (European Space Agency) programs as they result from history, present status, and decisions taken at the ministerial level conference in Granada, Spain is presented. The new factors taken into consideration for the long term plan proposed in Munich, Germany, the three strategic options for the reorientation of the ESA long term plan, and the essential elements of space transportation in the Granada long term plan in three areas of space activities, scientific, and commercial launches with expendable launch vehicles, manned flight and in-orbit infrastructure, and future transportation systems are outlined. The new ESA long term plan, in the field of space transportation systems, constitutes a reorientation of the initial program contemplated in previous councils at ministerial level. It aims at balancing the new economic situation with the new avenues of cooperation, and the outcome will be a new implementation of the space transportation systems policy.

Space Transportation Propulsion Systems

NASA Technical Reports Server (NTRS)

Liou, Meng-Sing; Stewart, Mark E.; Suresh, Ambady; Owen, A. Karl

2001-01-01

This report outlines the Space Transportation Propulsion Systems for the NPSS (Numerical Propulsion System Simulation) program. Topics include: 1) a review of Engine/Inlet Coupling Work; 2) Background/Organization of Space Transportation Initiative; 3) Synergy between High Performance Computing and Communications Program (HPCCP) and Advanced Space Transportation Program (ASTP); 4) Status of Space Transportation Effort, including planned deliverables for FY01-FY06, FY00 accomplishments (HPCCP Funded) and FY01 Major Milestones (HPCCP and ASTP); and 5) a review current technical efforts, including a review of the Rocket-Based Combined-Cycle (RBCC), Scope of Work, RBCC Concept Aerodynamic Analysis and RBCC Concept Multidisciplinary Analysis.

Industry survey of space system cost benefits from New Ways Of Doing Business

NASA Technical Reports Server (NTRS)

Rosmait, Russell L.

1992-01-01

The cost of designing, building and operating space system hardware has always been expensive. Small quantities of specialty parts escalate engineering design, production and operations cost. Funding cutbacks and shrinking revenues dictate aggressive cost saving programs. NASA's highest priority is providing economical transportation to and from space. Over the past three decades NASA has seen technological advances that provide grater efficiencies in designing, building, and operating of space system hardware. As future programs such as NLS, LUTE and SEI begin, these greater efficiencies and cost savings should be reflected in the cost models. There are several New Ways Of Doing Business (NWODB) which, when fully implemented will reduce space system costs. These philosophies and/or culture changes are integrated in five areas: (1) More Extensive Pre-Phase C/D & E, (2) Multi Year Funding Stability, (3) Improved Quality, Management and Procurement Processes, (4) Advanced Design Methods, and (5) Advanced Production Methods. Following is an overview of NWODB and the Cost Quantification Analysis results using an industry survey, one of the four quantification techniques used in the study. The NWODB Cost Quantification Analysis is a study performed at Marshall Space Flight Center by the Engineering Cost Group, Applied Research Incorporated and Pittsburg State University. This study took place over a period of four months in mid 1992. The purpose of the study was to identify potential NWODB which could lead to improved cost effectiveness within NASA and to quantify potential cost benefits that might accrue if these NWODB were implemented.

Unravelling Photocarrier Dynamics beyond the Space Charge Region for Photoelectrochemical Water Splitting

DOE PAGES

Zhang, Wenrui; Yan, Danhua; Appavoo, Kannatassen; ...

2017-04-18

Semiconductor photoelectrodes for photoelectrochemical (PEC) water splitting require efficient carrier generation, separation, and transport at and beyond the space charge region (SCR) formed at the aqueous interface. The trade-off between photon collection and minority carrier delivery governs the photoelectrode design and implies maximum water splitting efficiency at an electrode thickness equivalent to the light absorption depth. Here, using planar ZnO thin films as a model system, we identify the photocarriers beyond the SCR as another significant source to substantially enhance the PEC performance. The high-quality ZnO films synthesized by pulsed laser deposition feature very few deep trap states and supportmore » a long photocarrier lifetime. Combined with photoelectrochemical characterization, ultrafast spectroscopy, and numerical calculations, it is revealed that engineering the exciton concentration gradient by film thickness facilitates the inward diffusion of photocarriers from the neighboring illuminated region to the SCR and, therefore, achieves a record high quantum efficiency over 80% at a thickness far beyond its light absorption depth and the SCR width. Furthermore, these results elucidate the important role of the photocarriers beyond SCR for the PEC process and provide new insight into exploring the full potential for efficient photoelectrode materials with large exciton diffusivity.« less

Evaluation of railway transportation efficiency based on super-cross efficiency

NASA Astrophysics Data System (ADS)

Kuang, Xiuyuan

2018-01-01

The efficiency of railway transportation is an important index. It can measure the development of railway transportation enterprises, and the efficiency of railway transportation has become a hot issue in the study of railway development. Data envelopment analysis (DEA) has been widely applied to railway efficiency analysis. In this paper, BBC model and super-cross efficiency model are constructed by using DEA theory, taking the 18 Railway Bureau as the research object, with the mileage, the number of employees, locomotive number, average daily loading number as input indicators, the passenger turnover, freight turnover and transport income as output indicators, then calculated and evaluated comprehensive efficiency, pure technical efficiency and scale efficiency. We get that the super-cross efficiency is more in line with the actual situation. Getting the super-cross efficiency is more in line with the actual situation.

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

Kathy Lueders, program manager of NASA's Commercial Crew Program, speaks during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

NASA Administrator Charles Bolden listens to a reporter’s question after he announced the agency’s selection of Boeing and SpaceX to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

A Technology Plan for Enabling Commercial Space Business

NASA Technical Reports Server (NTRS)

Lyles, Garry M.

1997-01-01

The National Aeronautics and Space Administration's (NASA) Advanced Space Transportation Program is a customer driven, focused technology program that supports the NASA Strategic Plan and considers future commercial space business projections. The initial cycle of the Advanced Space Transportation Program implementation planning was conducted from December 1995 through February 1996 and represented increased NASA emphasis on broad base technology development with the goal of dramatic reductions in the cost of space transportation. The second planning cycle, conducted in January and February 1997, updated the program implementation plan based on changes in the external environment, increased maturity of advanced concept studies, and current technology assessments. The program has taken a business-like approach to technology development with a balanced portfolio of near, medium, and long-term strategic targets. Strategic targets are influenced by Earth science, space science, and exploration objectives as well as commercial space markets. Commercial space markets include those that would be enhanced by lower cost transportation as well as potential markets resulting in major increases in space business induced by reductions in transportation cost. The program plan addresses earth-to-orbit space launch, earth orbit operations and deep space systems. It also addresses all critical transportation system elements; including structures, thermal protection systems, propulsion, avionics, and operations. As these technologies are matured, integrated technology flight experiments such as the X-33 and X-34 flight demonstrator programs support near-term (one to five years) development or operational decisions. The Advanced Space Transportation Program and the flight demonstrator programs combine business planning, ground-based technology demonstrations and flight demonstrations that will permit industry and NASA to commit to revolutionary new space transportation systems beginning at the turn of the century and continuing far into the future.

CSTI Earth-to-orbit propulsion research and technology program overview

NASA Technical Reports Server (NTRS)

Gentz, Steven J.

1993-01-01

NASA supports a vigorous Earth-to-orbit (ETO) research and technology program as part of its Civil Space Technology Initiative. The purpose of this program is to provide an up-to-date technology base to support future space transportation needs for a new generation of lower cost, operationally efficient, long-lived and highly reliable ETO propulsion systems by enhancing the knowledge, understanding and design methodology applicable to advanced oxygen/hydrogen and oxygen/hydrocarbon ETO propulsion systems. Program areas of interest include analytical models, advanced component technology, instrumentation, and validation/verification testing. Organizationally, the program is divided between technology acquisition and technology verification as follows: (1) technology acquisition; and (2) technology verification.

Research and technology 1991 annual report

NASA Technical Reports Server (NTRS)

1991-01-01

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, NASA Kennedy is placing increasing emphasis on the center's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of the current mission, the technical tools are being developed which are needed to execute the center's mission relative to future programs. The Engineering Development Directorate encompasses most of the labs and other center resources that are key elements of research and technology program implementation and is responsible for implementation of the majority of the projects in this Kennedy Space Center 1991 annual report.

University of Tennessee Center for Space Transportation and Applied Research (CSTAR)

NASA Astrophysics Data System (ADS)

1995-10-01

The Center for Space Transportation and Applied Research had projects with space applications in six major areas: laser materials processing, artificial intelligence/expert systems, space transportation, computational methods, chemical propulsion, and electric propulsion. The closeout status of all these projects is addressed.

University of Tennessee Center for Space Transportation and Applied Research (CSTAR)

NASA Technical Reports Server (NTRS)

1995-01-01

The Center for Space Transportation and Applied Research had projects with space applications in six major areas: laser materials processing, artificial intelligence/expert systems, space transportation, computational methods, chemical propulsion, and electric propulsion. The closeout status of all these projects is addressed.

Space Transportation and Destination Facilities

NASA Technical Reports Server (NTRS)

Smitherman, David; McClure, Wallace

1999-01-01

The Space Transportation and Destination Facilities section focused on space transportation vehicles-from use of existing vehicles to development of specialized transports-and on space stations, space business parks, space hotels, and other facilities in space of the kind that eventually would provide services for general public space travel (PST) and tourism. For both transportation and destination facilities, the emphasis was on the identification of various strategies to enable a realistic incremental progression in the development and acquisition of such facilities, and the identification of issues that need resolution to enable formation of viable businesses. The approach was to determine the best: (1) Strategies for general PST and tourism development through the description and analysis of a wide range of possible future scenarios. With these scenarios in mind the section then identified. (2) Key issues to be explored. (3) opportunities to eliminate barriers. (4) Recommendations for future actions. (5) Top-level requirements and characteristics for general PST and tourism systems and services that would guide the development of transportation and destination facilities.

Phonon bottleneck identification in disordered nanoporous materials

NASA Astrophysics Data System (ADS)

Romano, Giuseppe; Grossman, Jeffrey C.

2017-09-01

Nanoporous materials are a promising platform for thermoelectrics in that they offer high thermal conductivity tunability while preserving good electrical properties, a crucial requirement for high-efficiency thermal energy conversion. Understanding the impact of the pore arrangement on thermal transport is pivotal to engineering realistic materials, where pore disorder is unavoidable. Although there has been considerable progress in modeling thermal size effects in nanostructures, it has remained a challenge to screen such materials over a large phase space due to the slow simulation time required for accurate results. We use density functional theory in connection with the Boltzmann transport equation to perform calculations of thermal conductivity in disordered porous materials. By leveraging graph theory and regressive analysis, we identify the set of pores representing the phonon bottleneck and obtain a descriptor for thermal transport, based on the sum of the pore-pore distances between such pores. This approach provide a simple tool to estimate phonon suppression in realistic porous materials for thermoelectric applications and enhance our understanding of heat transport in disordered materials.

Comparative analysis of quantitative efficiency evaluation methods for transportation networks

PubMed Central

He, Yuxin; Hong, Jian

2017-01-01

An effective evaluation of transportation network efficiency could offer guidance for the optimal control of urban traffic. Based on the introduction and related mathematical analysis of three quantitative evaluation methods for transportation network efficiency, this paper compares the information measured by them, including network structure, traffic demand, travel choice behavior and other factors which affect network efficiency. Accordingly, the applicability of various evaluation methods is discussed. Through analyzing different transportation network examples it is obtained that Q-H method could reflect the influence of network structure, traffic demand and user route choice behavior on transportation network efficiency well. In addition, the transportation network efficiency measured by this method and Braess’s Paradox can be explained with each other, which indicates a better evaluation of the real operation condition of transportation network. Through the analysis of the network efficiency calculated by Q-H method, it can also be drawn that a specific appropriate demand is existed to a given transportation network. Meanwhile, under the fixed demand, both the critical network structure that guarantees the stability and the basic operation of the network and a specific network structure contributing to the largest value of the transportation network efficiency can be identified. PMID:28399165

Comparative analysis of quantitative efficiency evaluation methods for transportation networks.

PubMed

He, Yuxin; Qin, Jin; Hong, Jian

2017-01-01

An effective evaluation of transportation network efficiency could offer guidance for the optimal control of urban traffic. Based on the introduction and related mathematical analysis of three quantitative evaluation methods for transportation network efficiency, this paper compares the information measured by them, including network structure, traffic demand, travel choice behavior and other factors which affect network efficiency. Accordingly, the applicability of various evaluation methods is discussed. Through analyzing different transportation network examples it is obtained that Q-H method could reflect the influence of network structure, traffic demand and user route choice behavior on transportation network efficiency well. In addition, the transportation network efficiency measured by this method and Braess's Paradox can be explained with each other, which indicates a better evaluation of the real operation condition of transportation network. Through the analysis of the network efficiency calculated by Q-H method, it can also be drawn that a specific appropriate demand is existed to a given transportation network. Meanwhile, under the fixed demand, both the critical network structure that guarantees the stability and the basic operation of the network and a specific network structure contributing to the largest value of the transportation network efficiency can be identified.

Transportation energy efficiency trends in the 1990s

DOT National Transportation Integrated Search

2003-04-01

In the 1990s : The transportation sector showed little increase : in energy efficiency as transportation activity and : energy use continued to grow. : Passenger travel energy-efficiency levels : improved slightly, mainly due to efficiency ga...

Overview of NASA Glenn Research Center Programs in Aero-Heat Transfer and Future Needs

NASA Technical Reports Server (NTRS)

Gaugler, Raymond E.

2002-01-01

This presentation concentrates on an overview of the NASA Glenn Research Center and the projects that are supporting Turbine Aero-Heat Transfer Research. The principal areas include the Ultra Efficient Engine Technology (UEET) Project, the Advanced Space Transportation Program (ASTP) Revolutionary Turbine Accelerator (RTA) Turbine Based Combined Cycle (TBCC) project, and the Propulsion & Power Base R&T - Smart Efficient Components (SEC), and Revolutionary Aeropropulsion Concepts (RAC) Projects. In addition, highlights are presented of the turbine aero-heat transfer work currently underway at NASA Glenn, focusing on the use of the Glenn-HT Navier- Stokes code as the vehicle for research in turbulence & transition modeling, grid topology generation, unsteady effects, and conjugate heat transfer.

77 FR 20531 - Correction of Authority Citations for Commercial Space Transportation

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-05

...-AI50, 2120-AI57, 2120-AI56, 2120-AI88] Correction of Authority Citations for Commercial Space..., Congress transferred the statute authorizing the FAA's commercial space transportation regulations. This...: Laura Montgomery, Senior Attorney for Commercial Space Transportation, Office of the Chief Counsel...

An Improved Neutron Transport Algorithm for HZETRN2006

NASA Astrophysics Data System (ADS)

Slaba, Tony

NASA's new space exploration initiative includes plans for long term human presence in space thereby placing new emphasis on space radiation analyses. In particular, a systematic effort of verification, validation and uncertainty quantification of the tools commonly used for radiation analysis for vehicle design and mission planning has begun. In this paper, the numerical error associated with energy discretization in HZETRN2006 is addressed; large errors in the low-energy portion of the neutron fluence spectrum are produced due to a numerical truncation error in the transport algorithm. It is shown that the truncation error results from the narrow energy domain of the neutron elastic spectral distributions, and that an extremely fine energy grid is required in order to adequately resolve the problem under the current formulation. Since adding a sufficient number of energy points will render the code computationally inefficient, we revisit the light-ion transport theory developed for HZETRN2006 and focus on neutron elastic interactions. The new approach that is developed numerically integrates with adequate resolution in the energy domain without affecting the run-time of the code and is easily incorporated into the current code. Efforts were also made to optimize the computational efficiency of the light-ion propagator; a brief discussion of the efforts is given along with run-time comparisons between the original and updated codes. Convergence testing is then completed by running the code for various environments and shielding materials with many different energy grids to ensure stability of the proposed method.

Transformational Spaceport and Range Concept of Operations: A Vision to Transform Ground and Launch Operations

NASA Technical Reports Server (NTRS)

2005-01-01

The Transformational Concept of Operations (CONOPS) provides a long-term, sustainable vision for future U.S. space transportation infrastructure and operations. This vision presents an interagency concept, developed cooperatively by the Department of Defense (DoD), the Federal Aviation Administration (FAA), and the National Aeronautics and Space Administration (NASA) for the upgrade, integration, and improved operation of major infrastructure elements of the nation s space access systems. The interagency vision described in the Transformational CONOPS would transform today s space launch infrastructure into a shared system that supports worldwide operations for a variety of users. The system concept is sufficiently flexible and adaptable to support new types of missions for exploration, commercial enterprise, and national security, as well as to endure further into the future when space transportation technology may be sufficiently advanced to enable routine public space travel as part of the global transportation system. The vision for future space transportation operations is based on a system-of-systems architecture that integrates the major elements of the future space transportation system - transportation nodes (spaceports), flight vehicles and payloads, tracking and communications assets, and flight traffic coordination centers - into a transportation network that concurrently accommodates multiple types of mission operators, payloads, and vehicle fleets. This system concept also establishes a common framework for defining a detailed CONOPS for the major elements of the future space transportation system. The resulting set of four CONOPS (see Figure 1 below) describes the common vision for a shared future space transportation system (FSTS) infrastructure from a variety of perspectives.

Human cell culture in a space bioreactor

NASA Technical Reports Server (NTRS)

Morrison, Dennis R.

1988-01-01

Microgravity offers new ways of handling fluids, gases, and growing mammalian cells in efficient suspension cultures. In 1976 bioreactor engineers designed a system using a cylindrical reactor vessel in which the cells and medium are slowly mixed. The reaction chamber is interchangeable and can be used for several types of cell cultures. NASA has methodically developed unique suspension type cell and recovery apparatus culture systems for bioprocess technology experiments and production of biological products in microgravity. The first Space Bioreactor was designed for microprocessor control, no gaseous headspace, circulation and resupply of culture medium, and slow mixing in very low shear regimes. Various ground based bioreactors are being used to test reactor vessel design, on-line sensors, effects of shear, nutrient supply, and waste removal from continuous culture of human cells attached to microcarriers. The small Bioreactor is being constructed for flight experiments in the Shuttle Middeck to verify systems operation under microgravity conditions and to measure the efficiencies of mass transport, gas transfer, oxygen consumption and control of low shear stress on cells.

Hybrid Power Management Program Evaluated Fuel Cell/Ultracapacitor Combinations and Developed Other New Applications

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2004-01-01

In fiscal year 2003, the continuation of the Hybrid Power Management (HPM) Program through NASA Glenn Research Center's Commercial Technology Office resulted in several new successful applications of this pioneering technology. HPM is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors, fuel cells, and photovoltaics. HPM has extremely wide potential, with applications from nanowatts to megawatts--including power generation, transportation systems, biotechnology systems, and space power systems. HPM has the potential to significantly alleviate global energy concerns, improve the environment, and stimulate the economy. Fuel cells provide excellent efficiency and energy density, but do not have good power density. In contrast, ultracapacitors have excellent power density and virtually unlimited cycle life. To improve the power density of the fuel cell, the combination of fuel cells and ultracapacitors was evaluated.

Space Radiation Transport Methods Development

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

2002-01-01

Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be utilized in the final design as verification of the deterministic method optimized design.

Wood-Graphene Oxide Composite for Highly Efficient Solar Steam Generation and Desalination.

PubMed

Liu, Keng-Ku; Jiang, Qisheng; Tadepalli, Sirimuvva; Raliya, Ramesh; Biswas, Pratim; Naik, Rajesh R; Singamaneni, Srikanth

2017-03-01

Solar steam generation is a highly promising technology for harvesting solar energy, desalination and water purification. We introduce a novel bilayered structure composed of wood and graphene oxide (GO) for highly efficient solar steam generation. The GO layer deposited on the microporous wood provides broad optical absorption and high photothermal conversion resulting in rapid increase in the temperature at the liquid surface. On the other hand, wood serves as a thermal insulator to confine the photothermal heat to the evaporative surface and to facilitate the efficient transport of water from the bulk to the photothermally active space. Owing to the tailored bilayer structure and the optimal thermo-optical properties of the individual components, the wood-GO composite structure exhibited a solar thermal efficiency of ∼83% under simulated solar excitation at a power density of 12 kW/m 2 . The novel composite structure demonstrated here is highly scalable and cost-efficient, making it an attractive material for various applications involving large light absorption, photothermal conversion and heat localization.

A 3DHZETRN Code in a Spherical Uniform Sphere with Monte Carlo Verification

NASA Technical Reports Server (NTRS)

Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

2014-01-01

The computationally efficient HZETRN code has been used in recent trade studies for lunar and Martian exploration and is currently being used in the engineering development of the next generation of space vehicles, habitats, and extra vehicular activity equipment. A new version (3DHZETRN) capable of transporting High charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation is under development. In the present report, new algorithms for light ion and neutron propagation with well-defined convergence criteria in 3D objects is developed and tested against Monte Carlo simulations to verify the solution methodology. The code will be available through the software system, OLTARIS, for shield design and validation and provides a basis for personal computer software capable of space shield analysis and optimization.

Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Schreiber, Jeffrey G.

1991-01-01

Technology development for Stirling convertors directed toward a dynamic power source for space applications is discussed. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although these applications appear to be quite different, their requirements complement each other. The advanced Stirling conversion system (ASCS) project at NASA Lewis Research Center is described. Each system design features a solar receiver/liquid metal heat transport system and a free-piston Stirling convertor with a means to provide nominally 25 kW of electric power to utility grid while meeting the US Department of Energy (DOE) performance and long term cost goals. The design is compared with other ASCS designs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jingchao, E-mail: zhang@unl.edu, E-mail: yyue@whu.edu.cn; Hong, Yang; Yue, Yanan, E-mail: zhang@unl.edu, E-mail: yyue@whu.edu.cn

As the dimensions of nanocircuits and nanoelectronics shrink, thermal energies are being generated in more confined spaces, making it extremely important and urgent to explore for efficient heat dissipation pathways. In this work, the phonon energy transport across graphene and hexagonal boron-nitride (h-BN) interface is studied using classic molecular dynamics simulations. Effects of temperature, interatomic bond strength, heat flux direction, and functionalization on interfacial thermal transport are investigated. It is found out that by hydrogenating graphene in the hybrid structure, the interfacial thermal resistance (R) between graphene and h-BN can be reduced by 76.3%, indicating an effective approach to manipulatemore » the interfacial thermal transport. Improved in-plane/out-of-plane phonon couplings and broadened phonon channels are observed in the hydrogenated graphene system by analyzing its phonon power spectra. The reported R results monotonically decrease with temperature and interatomic bond strengths. No thermal rectification phenomenon is observed in this interfacial thermal transport. Results reported in this work give the fundamental knowledge on graphene and h-BN thermal transport and provide rational guidelines for next generation thermal interface material designs.« less

Time-space and cognition-space transformations for transportation network analysis based on multidimensional scaling and self-organizing map

NASA Astrophysics Data System (ADS)

Hong, Zixuan; Bian, Fuling

2008-10-01

Geographic space, time space and cognition space are three fundamental and interrelated spaces in geographic information systems for transportation. However, the cognition space and its relationships to the time space and geographic space are often neglected. This paper studies the relationships of these three spaces in urban transportation system from a new perspective and proposes a novel MDS-SOM transformation method which takes the advantages of the techniques of multidimensional scaling (MDS) and self-organizing map (SOM). The MDS-SOM transformation framework includes three kinds of mapping: the geographic-time transformation, the cognition-time transformation and the time-cognition transformation. The transformations in our research provide a better understanding of the interactions of these three spaces and beneficial knowledge is discovered to help the transportation analysis and decision supports.

76 FR 30232 - Office of Commercial Space Transportation Safety Approval Performance Criteria

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-24

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Office of Commercial Space... levels associated with suborbital space flight. The reduced gravity levels are: --0.00 g 0.05 g for 17... Division (AST-200), FAA Office of Commercial Space Transportation (AST), 800 Independence Avenue, SW., Room...

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

From left, NASA Public Affairs Officer Stephanie Schierholz, NASA Administrator Charles Bolden, Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida, Kathy Lueders, program manager of NASA's Commercial Crew Program, and Astronaut Mike Fincke, a former commander of the International Space Station, are seen during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Commercial Crew Transportation Capability

NASA Image and Video Library

2014-09-16

Kathy Lueders, program manager of NASA's Commercial Crew Program, speaks, as Former astronaut Bob Cabana, director of NASA's Kennedy Space Center in Florida, left, and Astronaut Mike Fincke, a former commander of the International Space Station look on during a news conference where it was announced that Boeing and SpaceX have been selected to transport U.S. crews to and from the International Space Station using the Boeing CST-100 and the SpaceX Crew Dragon spacecraft, at NASA’s Kennedy Space Center in Cape Canaveral, Fla. on Tuesday, Sept. 16, 2014. These Commercial Crew Transportation Capability (CCtCap) contracts are designed to complete the NASA certification for a human space transportation system capable of carrying people into orbit. Once certification is complete, NASA plans to use these systems to transport astronauts to the space station and return them safely to Earth. Photo Credit: (NASA/Bill Ingalls)

Quantum transport in graphene in presence of strain-induced pseudo-Landau levels

NASA Astrophysics Data System (ADS)

Settnes, Mikkel; Leconte, Nicolas; Barrios-Vargas, Jose E.; Jauho, Antti-Pekka; Roche, Stephan

2016-09-01

We report on mesoscopic transport fingerprints in disordered graphene caused by strain-field induced pseudomagnetic Landau levels (pLLs). Efficient numerical real space calculations of the Kubo formula are performed for an ordered network of nanobubbles in graphene, creating pseudomagnetic fields up to several hundreds of Tesla, values inaccessible by real magnetic fields. Strain-induced pLLs yield enhanced scattering effects across the energy spectrum resulting in lower mean free path and enhanced localization effects. In the vicinity of the zeroth order pLL, we demonstrate an anomalous transport regime, where the mean free paths increases with disorder. We attribute this puzzling behavior to the low-energy sub-lattice polarization induced by the zeroth order pLL, which is unique to pseudomagnetic fields preserving time-reversal symmetry. These results, combined with the experimental feasibility of reversible deformation fields, open the way to tailor a metal-insulator transition driven by pseudomagnetic fields.

An Integrated Hybrid Transportation Architecture for Human Mars Expeditions

NASA Technical Reports Server (NTRS)

Merrill, Raymond G.; Chai, Patrick R.; Qu, Min

2015-01-01

NASA's Human Spaceflight Architecture Team is developing a reusable hybrid transportation architecture that uses both chemical and electric propulsion systems on the same vehicle to send crew and cargo to Mars destinations such as Phobos, Deimos, the surface of Mars, and other orbits around Mars. By applying chemical and electrical propulsion where each is most effective, the hybrid architecture enables a series of Mars trajectories that are more fuel-efficient than an all chemical architecture without significant increases in flight times. This paper presents an integrated Hybrid in-space transportation architecture for piloted missions and delivery of cargo. A concept for a Mars campaign including orbital and Mars surface missions is described in detail including a system concept of operations and conceptual design. Specific constraints, margin, and pinch points are identified for the architecture and opportunities for critical path commercial and international collaboration are discussed.

Transport velocity transformation - A convenient method for performance analysis of multilayer solar cell structure

NASA Technical Reports Server (NTRS)

Wolf, M.

1981-01-01

It is noted that in the case of low-level injection, space-charge quasi-neutrality, and spatially constant material parameters (including an electrostatic field), the individual layer can be treated analytically and the basic solar cell performance parameters can be evaluated from three equations. The first equation represents the transformation of the transport velocity across the layer from the other layer boundary. The second establishes the light-generated current output from the layer interface, under the influence of the transport velocities and minority-carrier density at both layer boundaries and of bulk recombination. The third equation describes the flow of these carriers across other layers. The power of the approach is considered to lie in its facility for analysis of the solar cell's performance layer by layer, giving a clear picture of the individual layer's influence on cell efficiency.

Cross-stream diffusion under pressure-driven flow in microchannels with arbitrary aspect ratios: a phase diagram study using a three-dimensional analytical model

PubMed Central

Song, Hongjun; Wang, Yi; Pant, Kapil

2011-01-01

This article presents a three-dimensional analytical model to investigate cross-stream diffusion transport in rectangular microchannels with arbitrary aspect ratios under pressure-driven flow. The Fourier series solution to the three-dimensional convection–diffusion equation is obtained using a double integral transformation method and associated eigensystem calculation. A phase diagram derived from the dimensional analysis is presented to thoroughly interrogate the characteristics in various transport regimes and examine the validity of the model. The analytical model is verified against both experimental and numerical models in terms of the concentration profile, diffusion scaling law, and mixing efficiency with excellent agreement (with <0.5% relative error). Quantitative comparison against other prior analytical models in extensive parameter space is also performed, which demonstrates that the present model accommodates much broader transport regimes with significantly enhanced applicability. PMID:22247719

Cross-stream diffusion under pressure-driven flow in microchannels with arbitrary aspect ratios: a phase diagram study using a three-dimensional analytical model.

PubMed

Song, Hongjun; Wang, Yi; Pant, Kapil

2012-01-01

This article presents a three-dimensional analytical model to investigate cross-stream diffusion transport in rectangular microchannels with arbitrary aspect ratios under pressure-driven flow. The Fourier series solution to the three-dimensional convection-diffusion equation is obtained using a double integral transformation method and associated eigensystem calculation. A phase diagram derived from the dimensional analysis is presented to thoroughly interrogate the characteristics in various transport regimes and examine the validity of the model. The analytical model is verified against both experimental and numerical models in terms of the concentration profile, diffusion scaling law, and mixing efficiency with excellent agreement (with <0.5% relative error). Quantitative comparison against other prior analytical models in extensive parameter space is also performed, which demonstrates that the present model accommodates much broader transport regimes with significantly enhanced applicability.

Optimization of a charge-state analyzer for electron cyclotron resonance ion source beams.

PubMed

Saminathan, S; Beijers, J P M; Kremers, H R; Mironov, V; Mulder, J; Brandenburg, S

2012-07-01

A detailed experimental and simulation study of the extraction of a 24 keV He(+) beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 π mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16% to 45%.

Use of prismatic films to control light distribution

NASA Technical Reports Server (NTRS)

Kneipp, K. G.

1994-01-01

Piping light for illumination purposes is a concept which has been around for a long time. In fact, it was the subject of an 1881 United States patent which proposed the use of mirrors inside a tube to reflect light from wall to wall down the tube. The use of conventional mirrors for this purpose, however, has not worked because mirrors do not reflect well enough. On the other hand, optical fibers composed of certain glasses or plastics are known to transport light much more efficiently. The light that enters is reflected back and forth within the walls of the fiber until it reaches the other end. This is possible by means of a principle known as 'total internal reflection'. No light escapes through the walls and very little is absorbed in the bulk of the fiber. However, while optical fibers are very efficient in transporting light, they are impractical for transporting large quantities of light. Lorne Whitehead, as a student at the University of British Columbia, recognized that prismatic materials could be used to create a 'prism light guide', a hollow structure that can efficiently transport large quantities of light. This invention is a pipe whose transparent walls are formed on the outside into precise prismatic facets. The facets are efficient total internal reflection mirrors which prevent light travelling down the guide from escaping. Very little light is absorbed by the pipe because light travels primarily in the air space within the hollow guide. And, because the guide is hollow, weight and cost factors are much more favorable than would be the case with very large solid fibers. Recent advances in precision micromachining, polymer processing, and certain other manufacturing technologies have made the development of OLF (Optical Lighting Film) possible. The process is referred to as 'microreplication' and has been found to have broad applicability in a number of diverse product areas.

Galactic Cosmic Ray Event-Based Risk Model (GERM) Code

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Plante, Ianik; Ponomarev, Artem L.; Kim, Myung-Hee Y.

2013-01-01

This software describes the transport and energy deposition of the passage of galactic cosmic rays in astronaut tissues during space travel, or heavy ion beams in patients in cancer therapy. Space radiation risk is a probability distribution, and time-dependent biological events must be accounted for physical description of space radiation transport in tissues and cells. A stochastic model can calculate the probability density directly without unverified assumptions about shape of probability density function. The prior art of transport codes calculates the average flux and dose of particles behind spacecraft and tissue shielding. Because of the signaling times for activation and relaxation in the cell and tissue, transport code must describe temporal and microspatial density of functions to correlate DNA and oxidative damage with non-targeted effects of signals, bystander, etc. These are absolutely ignored or impossible in the prior art. The GERM code provides scientists data interpretation of experiments; modeling of beam line, shielding of target samples, and sample holders; and estimation of basic physical and biological outputs of their experiments. For mono-energetic ion beams, basic physical and biological properties are calculated for a selected ion type, such as kinetic energy, mass, charge number, absorbed dose, or fluence. Evaluated quantities are linear energy transfer (LET), range (R), absorption and fragmentation cross-sections, and the probability of nuclear interactions after 1 or 5 cm of water equivalent material. In addition, a set of biophysical properties is evaluated, such as the Poisson distribution for a specified cellular area, cell survival curves, and DNA damage yields per cell. Also, the GERM code calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle in a selected material. The GERM code makes the numerical estimates of basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the first option, properties of monoenergetic beams are treated. In the second option, the transport of beams in different materials is treated. Similar biophysical properties as in the first option are evaluated for the primary ion and its secondary particles. Additional properties related to the nuclear fragmentation of the beam are evaluated. The GERM code is a computationally efficient Monte-Carlo heavy-ion-beam model. It includes accurate models of LET, range, residual energy, and straggling, and the quantum multiple scattering fragmentation (QMSGRG) nuclear database.

Space Resources Development: The Link Between Human Exploration and the Long-Term Commercialization of Space

NASA Technical Reports Server (NTRS)

Sanders, Gerald B.

2000-01-01

In a letter to the NASA Administrator, Dan Goldin, in January of 1999, the Office of Management and Budget (OMB) stated the following . OMB recommends that NASA consider commercialization in a broader context than the more focused efforts to date on space station and space shuttle commercialization. We suggest that NASA examine architectures that take advantage of a potentially robust future commercial infrastructure that could dramatically lower the cost of future human exploration." In response to this letter, the NASA Human Exploration and Development of Space (HEDS) Enterprise launched the BEDS Technology & Commercialization Initiative (HTCI) to link technology and system development for human exploration with the commercial development of space to emphasize the "D" (Development) in BEDS. The development of technologies and capabilities to utilize space resources is the first of six primary focus areas in this program. It is clear that Space Resources Development (SRD) is key for both long-term human exploration of our solar system and to the long-term commercialization of space since: a) it provides the technologies, products, and raw materials to support efficient space transportation and in-space construction and manufacturing, and b) it provides the capabilities and infrastructure to allow outpost growth, self-sufficiency, and commercial space service and utility industry activities.

Full space device optimization for solar cells.

PubMed

Baloch, Ahmer A B; Aly, Shahzada P; Hossain, Mohammad I; El-Mellouhi, Fedwa; Tabet, Nouar; Alharbi, Fahhad H

2017-09-20

Advances in computational materials have paved a way to design efficient solar cells by identifying the optimal properties of the device layers. Conventionally, the device optimization has been governed by single or double descriptors for an individual layer; mostly the absorbing layer. However, the performance of the device depends collectively on all the properties of the material and the geometry of each layer in the cell. To address this issue of multi-property optimization and to avoid the paradigm of reoccurring materials in the solar cell field, a full space material-independent optimization approach is developed and presented in this paper. The method is employed to obtain an optimized material data set for maximum efficiency and for targeted functionality for each layer. To ensure the robustness of the method, two cases are studied; namely perovskite solar cells device optimization and cadmium-free CIGS solar cell. The implementation determines the desirable optoelectronic properties of transport mediums and contacts that can maximize the efficiency for both cases. The resulted data sets of material properties can be matched with those in materials databases or by further microscopic material design. Moreover, the presented multi-property optimization framework can be extended to design any solid-state device.

Elegant Face-Down Liquid-Space-Restricted Deposition of CsPbBr3 Films for Efficient Carbon-Based All-Inorganic Planar Perovskite Solar Cells.

PubMed

Teng, Pengpeng; Han, Xiaopeng; Li, Jiawei; Xu, Ya; Kang, Lei; Wang, Yangrunqian; Yang, Ying; Yu, Tao

2018-03-21

It is a great challenge to obtain the uniform films of bromide-rich perovskites such as CsPbBr 3 in the two-step sequential solution process (two-step method), which was mainly due to the decomposition of the precursor films in solution. Herein, we demonstrated a novel and elegant face-down liquid-space-restricted deposition to inhibit the decomposition and fabricate high-quality CsPbBr 3 perovskite films. This method is highly reproducible, and the surface of the films was smooth and uniform with an average grain size of 860 nm. As a consequence, the planar perovskite solar cells (PSCs) without the hole-transport layer based on CsPbBr 3 and carbon electrodes exhibit enhanced power conversion efficiency (PCE) along with high open circuit voltage ( V OC ). The champion device has achieved a PCE of 5.86% with a V OC of 1.34 V, which to our knowledge is the highest performing CsPbBr 3 PSC in planar structure. Our results suggest an efficient and low-cost route to fabricate the high-quality planar all-inorganic PSCs.

Generalized free-space diffuse photon transport model based on the influence analysis of a camera lens diaphragm.

PubMed

Chen, Xueli; Gao, Xinbo; Qu, Xiaochao; Chen, Duofang; Ma, Xiaopeng; Liang, Jimin; Tian, Jie

2010-10-10

The camera lens diaphragm is an important component in a noncontact optical imaging system and has a crucial influence on the images registered on the CCD camera. However, this influence has not been taken into account in the existing free-space photon transport models. To model the photon transport process more accurately, a generalized free-space photon transport model is proposed. It combines Lambertian source theory with analysis of the influence of the camera lens diaphragm to simulate photon transport process in free space. In addition, the radiance theorem is also adopted to establish the energy relationship between the virtual detector and the CCD camera. The accuracy and feasibility of the proposed model is validated with a Monte-Carlo-based free-space photon transport model and physical phantom experiment. A comparison study with our previous hybrid radiosity-radiance theorem based model demonstrates the improvement performance and potential of the proposed model for simulating photon transport process in free space.

The Lower Tiers of the Space Transportation Industrial Base

DOT National Transportation Integrated Search

1995-08-01

The U.S. space transportation industry includes large and small providers of subsystems, components, and materials in areas such as propulsion, avionics, guidance, and structures. For each dollar spent on the procurement of space transportation syste...

DQE simulation of a-Se x-ray detectors using ARTEMIS

NASA Astrophysics Data System (ADS)

Fang, Yuan; Badano, Aldo

2016-03-01

Detective Quantum Efficiency (DQE) is one of the most important image quality metrics for evaluating the spatial resolution performance of flat-panel x-ray detectors. In this work, we simulate the DQE of amorphous selenium (a-Se) xray detectors with a detailed Monte Carlo transport code (ARTEMIS) for modeling semiconductor-based direct x-ray detectors. The transport of electron-hole pairs is achieved with a spatiotemporal model that accounts for recombination and trapping of carriers and Coulombic effects of space charge and external applied electric field. A range of x-ray energies has been simulated from 10 to 100 keV. The DQE results can be used to study the spatial resolution characteristics of detectors at different energies.

National Positioning, Navigation, and Timing Architecture Study

NASA Astrophysics Data System (ADS)

van Dyke, K.; Vicario, J.; Hothem, L.

2007-12-01

The purpose of the National Positioning, Navigation and Timing (PNT) Architecture effort is to help guide future PNT system-of-systems investment and implementation decisions. The Assistant Secretary of Defense for Networks and Information Integration and the Under Secretary of Transportation for Policy sponsored a National PNT Architecture study to provide more effective and efficient PNT capabilities focused on the 2025 timeframe and an evolutionary path for government provided systems and services. U.S. Space-Based PNT Policy states that the U.S. must continue to improve and maintain GPS, augmentations to GPS, and back-up capabilities to meet growing national, homeland, and economic security needs. PNT touches almost every aspect of people´s lives today. PNT is essential for Defense and Civilian applications ranging from the Department of Defense´s Joint network centric and precision operations to the transportation and telecommunications sectors, improving efficiency, increasing safety, and being more productive. Absence of an approved PNT architecture results in uncoordinated research efforts, lack of clear developmental paths, potentially wasteful procurements and inefficient deployment of PNT resources. The national PNT architecture effort evaluated alternative future mixes of global (space and non space-based) and regional PNT solutions, PNT augmentations, and autonomous PNT capabilities to address priorities identified in the DoD PNT Joint Capabilities Document (JCD) and civil equivalents. The path to achieving the Should-Be architecture is described by the National PNT Architecture's Guiding Principles, representing an overarching Vision of the US' role in PNT, an architectural Strategy to fulfill that Vision, and four Vectors which support the Strategy. The National PNT Architecture effort has developed nineteen recommendations. Five foundational recommendations are tied directly to the Strategy while the remaining fourteen individually support one of the Vectors, as will be described in this presentation. The results of this effort will support future decisions of bodies such as the DoD PNT and Civil Pos/Nav Executive Committees, as well as the National Space-Based PNT Executive Committee (EXCOM).

The Hybrid Propellant Module (HPM): A New Concept for Space Transfer in the Earth's Neighborhood and Beyond

NASA Technical Reports Server (NTRS)

Mankins, John C.; Mazanek, Daniel D.

2001-01-01

The safe, affordable and effective transfer of ever-larger payloads and eventually personnel beyond Low Earth Orbit (LEO) is a major challenge facing future commercial development and human exploration of space. Without reusable systems, sustained exploration or large scale development beyond LEO appears to be economically non-viable. However, reusable systems must be capable of both good fuel efficiency and "high utilization of capacity", or else economic costs will remain unacceptably high. Various options exist that can provide high fuel efficiency - for example, Solar Electric Propulsion Systems (SEPS) - but only at the cost of low thrust and concomitant long transit times. Chemical propulsion systems offer the potential for high thrust and short transit times - including both cryogenic and non-cryogenic options - but only at the cost of relatively low specific impulse (Isp). Nuclear thermal propulsion systems offer relatively good thrust-to-weight and Isp - but involve public concerns that may be insurmountable for all except the most-critical of public purposes. Fixed infrastructures have been suggested as one approach to solving this challenge; for example, rotating tether approaches. However, these systems tend to suffer from high initial costs or unacceptable operational constraints. A new concept has been identified - the Hybrid Propellant Module (HPM) - that integrates the best features of both chemical and solar electric transportation architectures. The HPM approach appears to hold promise of solving the issues associated with other approaches, opening a new family of capabilities for future space exploration and development of near-Earth space and beyond. This paper provides a summary overview of the challenge of Earth neighborhood transportation and discusses how various systems concepts might be applied to meet the needs of these architectures. The paper describes a new approach, the HPM, and illustrates the application of the concept for a typical mission concept. The paper concludes with a discussion of needed technologies and a possible timeline for the development and evolution of this class of systems concepts.

Design data brochure for CSI series V solar heating system

NASA Technical Reports Server (NTRS)

1978-01-01

Generalized information on system configuration, system sizing, and mechanical layout is presented to assist the architect or designer in preparing construction drawings and specifications for the installation of the CSI integrated solar heating systems. Efficiency in space utilization of a full length collector and the importance of proper sizing of the collector array are among the topics discussed. Details of storage and transport subsystems are provided along with drawings and specifications of all components of the CSI system.

Aviation & Space Weather Policy Research: Integrating Space Weather Observations & Forecasts into Operations

NASA Astrophysics Data System (ADS)

Fisher, G.; Jones, B.

2006-12-01

The American Meteorological Society and SolarMetrics Limited are conducting a policy research project leading to recommendations that will increase the safety, reliability, and efficiency of the nation's airline operations through more effective use of space weather forecasts and information. This study, which is funded by a 3-year National Science Foundation grant, also has the support of the Federal Aviation Administration and the Joint Planning and Development Office (JPDO) who is planning the Next Generation Air Transportation System. A major component involves interviewing and bringing together key people in the aviation industry who deal with space weather information. This research also examines public and industrial strategies and plans to respond to space weather information. The focus is to examine policy issues in implementing effective application of space weather services to the management of the nation's aviation system. The results from this project will provide government and industry leaders with additional tools and information to make effective decisions with respect to investments in space weather research and services. While space weather can impact the entire aviation industry, and this project will address national and international issues, the primary focus will be on developing a U.S. perspective for the airlines.

14 CFR 460.51 - Space flight participant training.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Space flight participant training. 460.51 Section 460.51 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry with a Space Flight...

14 CFR 460.51 - Space flight participant training.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Space flight participant training. 460.51 Section 460.51 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry with a Space Flight...

14 CFR 460.51 - Space flight participant training.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Space flight participant training. 460.51 Section 460.51 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry with a Space Flight...

14 CFR 460.51 - Space flight participant training.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Space flight participant training. 460.51 Section 460.51 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry with a Space Flight...

14 CFR 460.51 - Space flight participant training.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Space flight participant training. 460.51 Section 460.51 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING HUMAN SPACE FLIGHT REQUIREMENTS Launch and Reentry with a Space Flight...

NASA's approach to commercial cargo and crew transportation

NASA Astrophysics Data System (ADS)

Stone, Dennis; Lindenmoyer, Alan; French, George; Musk, Elon; Gump, David; Kathuria, Chirinjeev; Miller, Charles; Sirangelo, Mark; Pickens, Tom

2008-07-01

To stimulate the commercial space industry and potentially serve the logistics needs of the International Space Station (ISS) in the post-Space Shuttle era, the National Aeronautics and Space Administration (NASA) in 2006 began the Commercial Orbital Transportation Services (COTS) initiative. NASA entered into agreements with two U.S. firms, Rocketplane Kistler and Space Exploration Technologies to share up to 485,000,000 USD to demonstrate cargo transportation services to and from Low Earth orbit (LEO), with an option for additional funds to demonstrate human transportation services. Subsequently, NASA also entered into unfunded agreements with five companies to develop innovative space transportation capabilities. This paper reviews this unique initiative, describes the concepts of these seven companies, and discusses the potential of this emerging industry to make LEO more accessible.

In-Space Transportation for GEO Space Solar Power Satellites

NASA Technical Reports Server (NTRS)

Martin, James A.; Donnahue, Benjamin B.; Henley, Mark W.

1999-01-01

This report summarizes results of study tasks to evaluate design options for in-space transportation of geostationary Space Solar Power Satellites. Referring to the end-to-end architecture studies performed in 1988, this current activity focuses on transportation of Sun Tower satellite segments from an initial low Earth orbit altitude to a final position in geostationary orbit (GEO; i.e., 35,786 km altitude, circular, equatorial orbit). This report encompasses study activity for In-Space Transportation of GEO Space Solar Power (SSP) Satellites including: 1) assessment of requirements, 2) design of system concepts, 3) comparison of alternative system options, and 4) assessment of potential derivatives.

Coarse mesh and one-cell block inversion based diffusion synthetic acceleration

NASA Astrophysics Data System (ADS)

Kim, Kang-Seog

DSA (Diffusion Synthetic Acceleration) has been developed to accelerate the SN transport iteration. We have developed solution techniques for the diffusion equations of FLBLD (Fully Lumped Bilinear Discontinuous), SCB (Simple Comer Balance) and UCB (Upstream Corner Balance) modified 4-step DSA in x-y geometry. Our first multi-level method includes a block Gauss-Seidel iteration for the discontinuous diffusion equation, uses the continuous diffusion equation derived from the asymptotic analysis, and avoids void cell calculation. We implemented this multi-level procedure and performed model problem calculations. The results showed that the FLBLD, SCB and UCB modified 4-step DSA schemes with this multi-level technique are unconditionally stable and rapidly convergent. We suggested a simplified multi-level technique for FLBLD, SCB and UCB modified 4-step DSA. This new procedure does not include iterations on the diffusion calculation or the residual calculation. Fourier analysis results showed that this new procedure was as rapidly convergent as conventional modified 4-step DSA. We developed new DSA procedures coupled with 1-CI (Cell Block Inversion) transport which can be easily parallelized. We showed that 1-CI based DSA schemes preceded by SI (Source Iteration) are efficient and rapidly convergent for LD (Linear Discontinuous) and LLD (Lumped Linear Discontinuous) in slab geometry and for BLD (Bilinear Discontinuous) and FLBLD in x-y geometry. For 1-CI based DSA without SI in slab geometry, the results showed that this procedure is very efficient and effective for all cases. We also showed that 1-CI based DSA in x-y geometry was not effective for thin mesh spacings, but is effective and rapidly convergent for intermediate and thick mesh spacings. We demonstrated that the diffusion equation discretized on a coarse mesh could be employed to accelerate the transport equation. Our results showed that coarse mesh DSA is unconditionally stable and is as rapidly convergent as fine mesh DSA in slab geometry. For x-y geometry our coarse mesh DSA is very effective for thin and intermediate mesh spacings independent of the scattering ratio, but is not effective for purely scattering problems and high aspect ratio zoning. However, if the scattering ratio is less than about 0.95, this procedure is very effective for all mesh spacing.

Changing the Cultural Paradigm to Meet Emerging Requirements

NASA Technical Reports Server (NTRS)

Robbins, William W.

2007-01-01

This viewgraph presentation reviews changes that are required in Space Transportation. This new transportation paradigm from the reliance on the Space Shuttle to a mixture of space transportation vehicles, i.e., the Russian Progress, vehicle, the Japanese HTV, the European ATV and other commercial orbital transportation systems, requires a new cultural paradigm. This new paradigm is outlined, and reviewed.

Progression of Space Transportation - Transitioning from Government to Commercial

NASA Technical Reports Server (NTRS)

Lueders, Kathy

2015-01-01

Spaceflight began as the exclusive province of government, however, starting in the 1980's the United States began to promote commercial participation in space transportation. Beginning with Executive policy and extending through legislation and regulation, NASA has embarked on facilitating the commercialization of space transportation to serve NASA needs and enable a non-NASA market place. This presentation provides background on the transition to commercial space transportation and the specific role NASA is playing in that endeavor.

Measurement and modelling of reactive transport in geological barriers for nuclear waste containment

DOE PAGES

Xiong, Qingrong; Joseph, Claudia; Schmeide, Katja; ...

2015-10-26

Compacted clays are considered as excellent candidates for barriers to radionuclide transport in future repositories for nuclear waste due to their very low hydraulic permeability. Diffusion is the dominant transport mechanism, controlled by a nano-scale pore system. Assessment of the clays' long-term containment function requires adequate modelling of such pore systems and their evolution. Existing characterisation techniques do not provide complete pore space information for effective modelling, such as pore and throat size distributions and connectivity. Special network models for reactive transport are proposed here using the complimentary character of the pore space and the solid phase. Here, this balancesmore » the insufficient characterisation information and provides the means for future mechanical–physical–chemical coupling. The anisotropy and heterogeneity of clays is represented using different length parameters and percentage of pores in different directions. Resulting networks are described as mathematical graphs with efficient discrete calculus formulation of transport. Opalinus Clay (OPA) is chosen as an example. Experimental data for the tritiated water (HTO) and U(VI) diffusion through OPA are presented. Calculated diffusion coefficients of HTO and uranium species are within the ranges of the experimentally determined data in different clay directions. This verifies the proposed pore network model and validates that uranium complexes are diffusing as neutral species in OPA. In the case of U(VI) diffusion the method is extended to account for sorption and convection. Finally, rather than changing pore radii by coarse grained mathematical formula, physical sorption is simulated in each pore, which is more accurate and realistic.« less

Parameterizing the Transport Pathways for Cell Invasion in Complex Scaffold Architectures

PubMed Central

Ashworth, Jennifer C.; Mehr, Marco; Buxton, Paul G.; Best, Serena M.

2016-01-01

Interconnecting pathways through porous tissue engineering scaffolds play a vital role in determining nutrient supply, cell invasion, and tissue ingrowth. However, the global use of the term “interconnectivity” often fails to describe the transport characteristics of these pathways, giving no clear indication of their potential to support tissue synthesis. This article uses new experimental data to provide a critical analysis of reported methods for the description of scaffold transport pathways, ranging from qualitative image analysis to thorough structural parameterization using X-ray Micro-Computed Tomography. In the collagen scaffolds tested in this study, it was found that the proportion of pore space perceived to be accessible dramatically changed depending on the chosen method of analysis. Measurements of % interconnectivity as defined in this manner varied as a function of direction and connection size, and also showed a dependence on measurement length scale. As an alternative, a method for transport pathway parameterization was investigated, using percolation theory to calculate the diameter of the largest sphere that can travel to infinite distance through a scaffold in a specified direction. As proof of principle, this approach was used to investigate the invasion behavior of primary fibroblasts in response to independent changes in pore wall alignment and pore space accessibility, parameterized using the percolation diameter. The result was that both properties played a distinct role in determining fibroblast invasion efficiency. This example therefore demonstrates the potential of the percolation diameter as a method of transport pathway parameterization, to provide key structural criteria for application-based scaffold design. PMID:26888449

Measurement and modelling of reactive transport in geological barriers for nuclear waste containment.

PubMed

Xiong, Qingrong; Joseph, Claudia; Schmeide, Katja; Jivkov, Andrey P

2015-11-11

Compacted clays are considered as excellent candidates for barriers to radionuclide transport in future repositories for nuclear waste due to their very low hydraulic permeability. Diffusion is the dominant transport mechanism, controlled by a nano-scale pore system. Assessment of the clays' long-term containment function requires adequate modelling of such pore systems and their evolution. Existing characterisation techniques do not provide complete pore space information for effective modelling, such as pore and throat size distributions and connectivity. Special network models for reactive transport are proposed here using the complimentary character of the pore space and the solid phase. This balances the insufficient characterisation information and provides the means for future mechanical-physical-chemical coupling. The anisotropy and heterogeneity of clays is represented using different length parameters and percentage of pores in different directions. Resulting networks are described as mathematical graphs with efficient discrete calculus formulation of transport. Opalinus Clay (OPA) is chosen as an example. Experimental data for the tritiated water (HTO) and U(vi) diffusion through OPA are presented. Calculated diffusion coefficients of HTO and uranium species are within the ranges of the experimentally determined data in different clay directions. This verifies the proposed pore network model and validates that uranium complexes are diffusing as neutral species in OPA. In the case of U(vi) diffusion the method is extended to account for sorption and convection. Rather than changing pore radii by coarse grained mathematical formula, physical sorption is simulated in each pore, which is more accurate and realistic.

Next Generation Civil Transport Aircraft Design Considerations for Improving Vehicle and System-Level Efficiency

NASA Technical Reports Server (NTRS)

Acosta, Diana M.; Guynn, Mark D.; Wahls, Richard A.; DelRosario, Ruben,

2013-01-01

The future of aviation will benefit from research in aircraft design and air transportation management aimed at improving efficiency and reducing environmental impacts. This paper presents civil transport aircraft design trends and opportunities for improving vehicle and system-level efficiency. Aircraft design concepts and the emerging technologies critical to reducing thrust specific fuel consumption, reducing weight, and increasing lift to drag ratio currently being developed by NASA are discussed. Advancements in the air transportation system aimed towards system-level efficiency are discussed as well. Finally, the paper describes the relationship between the air transportation system, aircraft, and efficiency. This relationship is characterized by operational constraints imposed by the air transportation system that influence aircraft design, and operational capabilities inherent to an aircraft design that impact the air transportation system.

Product Lifecycle Management and the Quest for Sustainable Space Transportation Solutions

NASA Technical Reports Server (NTRS)

Caruso, Pamela W.

2009-01-01

This viewgraph presentation reviews NASA Marshall's effort to sustain space transportation solutions through product lines that include: 1) Propulsion and Transportation Systems; 2) Life Support Systems; and 3) and Earth and Space Science Spacecraft Systems, and Operations.

76 FR 20070 - Commercial Space Transportation Safety Approval Performance Criteria

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... application. Background: NASTAR applied for, and received, a safety approval for the ability of its Space... approval are applicant developed per 14 CFR 414.19 (a)(4). NASTAR's [[Page 20071

Transportation Energy Efficiency Program (TEEP) Report Abstracts

DOT National Transportation Integrated Search

1977-04-15

This bibliography summarizes the published research accomplished for the Department of Transportation's Transportation Energy Efficiency Program and its predecessor, the Automotive Energy Efficiency Program. The reports are indexed by corporate autho...

49 CFR 176.168 - Transport of Class 1 (explosive) materials in vehicle spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Transport of Class 1 (explosive) materials in vehicle spaces. 176.168 Section 176.168 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY VESSEL Detailed...

One-Dimensional Electron Transport Layers for Perovskite Solar Cells

PubMed Central

Thakur, Ujwal K.; Kisslinger, Ryan; Shankar, Karthik

2017-01-01

The electron diffusion length (Ln) is smaller than the hole diffusion length (Lp) in many halide perovskite semiconductors meaning that the use of ordered one-dimensional (1D) structures such as nanowires (NWs) and nanotubes (NTs) as electron transport layers (ETLs) is a promising method of achieving high performance halide perovskite solar cells (HPSCs). ETLs consisting of oriented and aligned NWs and NTs offer the potential not merely for improved directional charge transport but also for the enhanced absorption of incoming light and thermodynamically efficient management of photogenerated carrier populations. The ordered architecture of NW/NT arrays affords superior infiltration of a deposited material making them ideal for use in HPSCs. Photoconversion efficiencies (PCEs) as high as 18% have been demonstrated for HPSCs using 1D ETLs. Despite the advantages of 1D ETLs, there are still challenges that need to be overcome to achieve even higher PCEs, such as better methods to eliminate or passivate surface traps, improved understanding of the hetero-interface and optimization of the morphology (i.e., length, diameter, and spacing of NWs/NTs). This review introduces the general considerations of ETLs for HPSCs, deposition techniques used, and the current research and challenges in the field of 1D ETLs for perovskite solar cells. PMID:28468280

A SEMI-LAGRANGIAN TWO-LEVEL PRECONDITIONED NEWTON-KRYLOV SOLVER FOR CONSTRAINED DIFFEOMORPHIC IMAGE REGISTRATION.

PubMed

Mang, Andreas; Biros, George

2017-01-01

We propose an efficient numerical algorithm for the solution of diffeomorphic image registration problems. We use a variational formulation constrained by a partial differential equation (PDE), where the constraints are a scalar transport equation. We use a pseudospectral discretization in space and second-order accurate semi-Lagrangian time stepping scheme for the transport equations. We solve for a stationary velocity field using a preconditioned, globalized, matrix-free Newton-Krylov scheme. We propose and test a two-level Hessian preconditioner. We consider two strategies for inverting the preconditioner on the coarse grid: a nested preconditioned conjugate gradient method (exact solve) and a nested Chebyshev iterative method (inexact solve) with a fixed number of iterations. We test the performance of our solver in different synthetic and real-world two-dimensional application scenarios. We study grid convergence and computational efficiency of our new scheme. We compare the performance of our solver against our initial implementation that uses the same spatial discretization but a standard, explicit, second-order Runge-Kutta scheme for the numerical time integration of the transport equations and a single-level preconditioner. Our improved scheme delivers significant speedups over our original implementation. As a highlight, we observe a 20 × speedup for a two dimensional, real world multi-subject medical image registration problem.

Insights into the role of wettability in cathode catalyst layer of proton exchange membrane fuel cell; pore scale immiscible flow and transport processes

NASA Astrophysics Data System (ADS)

Fathi, H.; Raoof, A.; Mansouri, S. H.

2017-05-01

The production of liquid water in cathode catalyst layer, CCL, is a significant barrier to increase the efficiency of proton exchange membrane fuel cell. Here we present, for the first time, a direct three-dimensional pore-scale modelling to look at the complex immiscible two-phase flow in CCL. After production of the liquid water at the surface of CCL agglomerates due to the electrochemical reactions, water spatial distribution affects transport of oxygen through the CCL as well as the rate of reaction at the agglomerate surfaces. To explore the wettability effects, we apply hydrophilic and hydrophobic properties using different surface contact angles. Effective diffusivity is calculated under several water saturation levels. Results indicate larger diffusive transport values for hydrophilic domain compared to the hydrophobic media where the liquid water preferentially floods the larger pores. However, hydrophobic domain showed more available surface area and higher oxygen consumption rate at the reaction sites under various saturation levels, which is explained by the effect of wettability on pore-scale distribution of water. Hydrophobic domain, with a contact angle of 150, reveals efficient water removal where only 28% of the pore space stays saturated. This condition contributes to the enhanced available reaction surface area and oxygen diffusivity.

Future space transportation systems systems analysis study, phase 1 technical report

NASA Technical Reports Server (NTRS)

1975-01-01

The requirements of projected space programs (1985-1995) for transportation vehicles more advanced than the space shuttle are discussed. Several future program options are described and their transportation needs are analyzed. Alternative systems approaches to meeting these needs are presented.

14 CFR 1274.930 - Travel and transportation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Travel and transportation. 1274.930 Section 1274.930 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION COOPERATIVE AGREEMENTS WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.930 Travel and transportation...

14 CFR 1274.930 - Travel and transportation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Travel and transportation. 1274.930 Section 1274.930 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION COOPERATIVE AGREEMENTS WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.930 Travel and transportation...

14 CFR 1274.930 - Travel and transportation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Travel and transportation. 1274.930 Section 1274.930 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION COOPERATIVE AGREEMENTS WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.930 Travel and transportation...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

Solar Electric Propulsion for Mars Exploration

NASA Technical Reports Server (NTRS)

Hack, Kurt J.

1998-01-01

Highly propellant-efficient electric propulsion is being combined with advanced solar power technology to provide a non-nuclear transportation option for the human exploration of Mars. By virtue of its high specific impulse, electric propulsion offers a greater change in spacecraft velocity for each pound of propellant than do conventional chemical rockets. As a result, a mission to Mars based on solar electric propulsion (SEP) would require fewer heavy-lift launches than a traditional all-chemical space propulsion scenario would. Performance, as measured by mass to orbit and trip time, would be comparable to the NASA design reference mission for human Mars exploration, which utilizes nuclear thermal propulsion; but it would avoid the issues surrounding the use of nuclear reactors in space.

Characterization of Space Shuttle Ascent Debris Aerodynamics Using CFD Methods

NASA Technical Reports Server (NTRS)

Murman, Scott M.; Aftosmis, Michael J.; Rogers, Stuart E.

2005-01-01

An automated Computational Fluid Dynamics process for determining the aerodynamic Characteristics of debris shedding from the Space Shuttle Launch Vehicle during ascent is presented. This process uses Cartesian fully-coupled, six-degree-of-freedom simulations of isolated debris pieces in a Monte Carlo fashion to produce models for the drag and crossrange behavior over a range of debris shapes and shedding scenarios. A validation of the Cartesian methods against ballistic range data for insulating foam debris shapes at flight conditions, as well as validation of the resulting models, are both contained. These models are integrated with the existing shuttle debris transport analysis software to provide an accurate and efficient engineering tool for analyzing debris sources and their potential for damage.

Efficient Long-Range Hole Transport Through G-Quadruplexes.

PubMed

Wu, Jingyuan; Meng, Zhenyu; Lu, Yunpeng; Shao, Fangwei

2017-10-09

DNA offers a means of long-range charge transport for biology and electric nanodevices. Here, a series of tetra-stranded G-quadruplexes were assembled within a dendritic DNA architecture to explore oxidative charge transport (hole transport) through the G-quadruplex. Efficient charge transport was achieved over 28 Å upon UV irradiation. Over a longer G-quadruplex bridge, hole transport was escalated to a higher efficiency, which resulted in a higher yield than that of the optimal duplex DNA for charge transport, that is, the adenine tract. Efficient long-range hole transport suggests tetra-stranded G-quadruplexes, instead of an oxidation hotspot, hold better potential as an electron conduit than duplex DNA. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An improved numerical method for the kernel density functional estimation of disperse flow

NASA Astrophysics Data System (ADS)

Smith, Timothy; Ranjan, Reetesh; Pantano, Carlos

2014-11-01

We present an improved numerical method to solve the transport equation for the one-point particle density function (pdf), which can be used to model disperse flows. The transport equation, a hyperbolic partial differential equation (PDE) with a source term, is derived from the Lagrangian equations for a dilute particle system by treating position and velocity as state-space variables. The method approximates the pdf by a discrete mixture of kernel density functions (KDFs) with space and time varying parameters and performs a global Rayleigh-Ritz like least-square minimization on the state-space of velocity. Such an approximation leads to a hyperbolic system of PDEs for the KDF parameters that cannot be written completely in conservation form. This system is solved using a numerical method that is path-consistent, according to the theory of non-conservative hyperbolic equations. The resulting formulation is a Roe-like update that utilizes the local eigensystem information of the linearized system of PDEs. We will present the formulation of the base method, its higher-order extension and further regularization to demonstrate that the method can predict statistics of disperse flows in an accurate, consistent and efficient manner. This project was funded by NSF Project NSF-DMS 1318161.

Evaluation of Spacecraft Shielding Effectiveness for Radiation Protection

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Wilson, John W.

1999-01-01

The potential for serious health risks from solar particle events (SPE) and galactic cosmic rays (GCR) is a critical issue in the NASA strategic plan for the Human Exploration and Development of Space (HEDS). The excess cost to protect against the GCR and SPE due to current uncertainties in radiation transmission properties and cancer biology could be exceedingly large based on the excess launch costs to shield against uncertainties. The development of advanced shielding concepts is an important risk mitigation area with the potential to significantly reduce risk below conventional mission designs. A key issue in spacecraft material selection is the understanding of nuclear reactions on the transmission properties of materials. High-energy nuclear particles undergo nuclear reactions in passing through materials and tissue altering their composition and producing new radiation types. Spacecraft and planetary habitat designers can utilize radiation transport codes to identify optimal materials for lowering exposures and to optimize spacecraft design to reduce astronaut exposures. To reach these objectives will require providing design engineers with accurate data bases and computationally efficient software for describing the transmission properties of space radiation in materials. Our program will reduce the uncertainty in the transmission properties of space radiation by improving the theoretical description of nuclear reactions and radiation transport, and provide accurate physical descriptions of the track structure of microscopic energy deposition.

Advanced Space Transportation Program (ASTP)

NASA Image and Video Library

2003-07-21

An ion thruster is removed from a vacuum chamber at NASA's Jet Propulsion Laboratory in Pasadena, California. The thruster, a spare engine from NASA's Deep Space 1 mission, with a designed life of 8,000 hours, ran for a record 30,352 hours (nearly 5 years) giving researchers the ability to observe its performance and wear at different power levels throughout the test. This information will be vital to future missions that use ion propulsion. Ion propulsion systems can be very lightweight, rurning on just a few grams of xenon gas a day. Xenon is the same gas that is found in photo flash bulbs. This fuel efficiency can lower launch vehicle costs. The successful Deep Space 1 mission featured the first use of an ion engine as the primary means of propulsion on a NASA spacecraft. NASA's next-generation ion propulsion efforts are implemented by the Marshall Space Flight Center. The program seeks to develop advanced propulsion technologies that will significantly reduce cost, mass, or travel times.

KSC-01pp1758

NASA Image and Video Library

2001-11-29

KENNEDY SPACE CENTER, Fla. -- In Hangar A&E, workers watch as an overhead crane lifts the Advanced Camera for Surveys out of its transportation container. Part of the payload on the Hubble Space Telescope Servicing Mission, STS-109, the ACS will increase the discovery efficiency of the HST by a factor of ten. It consists of three electronic cameras and a complement of filters and dispersers that detect light from the ultraviolet to the near infrared (1200 - 10,000 angstroms). The ACS was built through a collaborative effort between Johns Hopkins University, Goddard Space Flight Center, Ball Aerospace Corporation and Space Telescope Science Institute. Tasks for the mission include replacing Solar Array 2 with Solar Array 3, replacing the Power Control Unit, removing the Faint Object Camera and installing the ACS, installing the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Cooling System, and installing New Outer Blanket Layer insulation on bays 5 through 8. Mission STS-109 is scheduled for launch Feb. 14, 2002

Research on Evaluation of resource allocation efficiency of transportation system based on DEA

NASA Astrophysics Data System (ADS)

Zhang, Zhehui; Du, Linan

2017-06-01

In this paper, we select the time series data onto 1985-2015 years, construct the land (shoreline) resources, capital and labor as inputs. The index system of the output is freight volume and passenger volume, we use Quantitative analysis based on DEA method evaluated the resource allocation efficiency of railway, highway, water transport and civil aviation in China. Research shows that the resource allocation efficiency of various modes of transport has obvious difference, and the impact on scale efficiency is more significant. The most important two ways to optimize the allocation of resources to improve the efficiency of the combination of various modes of transport is promoting the co-ordination of various modes of transport and constructing integrated transportation system.

Membrane transporters as mediators of synaptic dopamine dynamics: implications for disease

PubMed Central

Lohr, Kelly M.; Masoud, Shababa T.; Salahpour, Ali; Miller, Gary W.

2016-01-01

Dopamine was first identified as a neurotransmitter localized to the midbrain over 50 years ago. The dopamine transporter (DAT; SLC6A3) and the vesicular monoamine transporter 2 (VMAT2; SLC18A2) are two regulators of dopamine homeostasis in the presynaptic neuron. DAT transports dopamine from the extracellular space into the cytosol of the presynaptic terminal. VMAT2 then packages this cytosolic dopamine into vesicular compartments for subsequent release upon neurotransmission. Thus, DAT and VMAT2 act in concert to move transmitter efficiently throughout the neuron. The accumulation of dopamine in the neuronal cytosol can trigger oxidative stress and neurotoxicity, suggesting that the proper compartmentalization of dopamine is critical for neuron function and risk of disease. For decades, studies have examined the effects of reduced transporter function in mice (e.g. DAT-KO, VMAT2-KO, VMAT2-deficient). However, we have only recently been able to assess the effects of elevated transporter expression using BAC transgenic methods (DAT-tg, VMAT2-HI mice). Complemented with in vitro work and neurochemical techniques to assess dopamine compartmentalization, a new focus on the importance of transporter proteins as both models of human disease and potential drug targets has emerged. Here we review the importance of DAT and VMAT2 function in the delicate balance of neuronal dopamine. PMID:27520881

Commercialization of space transportation : exploring the impact of the National Space Transportation Policy

DOT National Transportation Integrated Search

1998-09-01

The 1994 National Space Transportation Policy designates the roles of the DoD, NASA and the Departments of Transportaiton and Commerce to "identify and promote innovative types of arrangements between the US government and the private sector in order...

A Systems Approach to Developing an Affordable Space Ground Transportation Architecture using a Commonality Approach

NASA Technical Reports Server (NTRS)

Garcia, Jerry L.; McCleskey, Carey M.; Bollo, Timothy R.; Rhodes, Russel E.; Robinson, John W.

2012-01-01

This paper presents a structured approach for achieving a compatible Ground System (GS) and Flight System (FS) architecture that is affordable, productive and sustainable. This paper is an extension of the paper titled "Approach to an Affordable and Productive Space Transportation System" by McCleskey et al. This paper integrates systems engineering concepts and operationally efficient propulsion system concepts into a structured framework for achieving GS and FS compatibility in the mid-term and long-term time frames. It also presents a functional and quantitative relationship for assessing system compatibility called the Architecture Complexity Index (ACI). This paper: (1) focuses on systems engineering fundamentals as it applies to improving GS and FS compatibility; (2) establishes mid-term and long-term spaceport goals; (3) presents an overview of transitioning a spaceport to an airport model; (4) establishes a framework for defining a ground system architecture; (5) presents the ACI concept; (6) demonstrates the approach by presenting a comparison of different GS architectures; and (7) presents a discussion on the benefits of using this approach with a focus on commonality.

14 CFR 415.8 - Human space flight.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Human space flight. 415.8 Section 415.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE General § 415.8 Human space flight. To obtain a launch license, an...

14 CFR 415.8 - Human space flight.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Human space flight. 415.8 Section 415.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE General § 415.8 Human space flight. To obtain a launch license, an...

14 CFR 415.8 - Human space flight.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Human space flight. 415.8 Section 415.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE General § 415.8 Human space flight. To obtain a launch license, an...

14 CFR 415.8 - Human space flight.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Human space flight. 415.8 Section 415.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE General § 415.8 Human space flight. To obtain a launch license, an...

14 CFR 415.8 - Human space flight.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Human space flight. 415.8 Section 415.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH LICENSE General § 415.8 Human space flight. To obtain a launch license, an...

The Association Between Transportation and Life-Space Mobility in Community-Dwelling Older People With or Without Walking Difficulties.

PubMed

Viljanen, Anne; Mikkola, Tuija M; Rantakokko, Merja; Portegijs, Erja; Rantanen, Taina

2016-09-01

The aim of this study is to examine whether a persons' most frequently used mode of transportation is associated with life-space mobility and whether the association differs between persons with or without walking difficulties. Life-space mobility was measured with the Life-Space Assessment in 848 community-dwelling men and women aged 75 to 90 years. Six separate mobility groups were formed according to the most frequently used mode of transportation (car driver, car passenger, public transportation) combined with the presence or absence of difficulties walking 2 km. Car drivers without walking difficulties had the highest life-space mobility scores, and car passengers with walking difficulties had the lowest scores. Mode of transportation influenced the odds for restricted life space differently depending on whether or not the person had walking difficulties. To support community mobility among older persons, it would be important to improve different transportation options to meet older persons' individual wishes, needs, and resources. © The Author(s) 2015.

Modeling Solar Energetic Particle Transport near a Wavy Heliospheric Current Sheet

NASA Astrophysics Data System (ADS)

Battarbee, Markus; Dalla, Silvia; Marsh, Mike S.

2018-02-01

Understanding the transport of solar energetic particles (SEPs) from acceleration sites at the Sun into interplanetary space and to the Earth is an important question for forecasting space weather. The interplanetary magnetic field (IMF), with two distinct polarities and a complex structure, governs energetic particle transport and drifts. We analyze for the first time the effect of a wavy heliospheric current sheet (HCS) on the propagation of SEPs. We inject protons close to the Sun and propagate them by integrating fully 3D trajectories within the inner heliosphere in the presence of weak scattering. We model the HCS position using fits based on neutral lines of magnetic field source surface maps (SSMs). We map 1 au proton crossings, which show efficient transport in longitude via HCS, depending on the location of the injection region with respect to the HCS. For HCS tilt angles around 30°–40°, we find significant qualitative differences between A+ and A‑ configurations of the IMF, with stronger fluences along the HCS in the former case but with a distribution of particles across a wider range of longitudes and latitudes in the latter. We show how a wavy current sheet leads to longitudinally periodic enhancements in particle fluence. We show that for an A+ IMF configuration, a wavy HCS allows for more proton deceleration than a flat HCS. We find that A‑ IMF configurations result in larger average fluences than A+ IMF configurations, due to a radial drift component at the current sheet.

Orbital Spacecraft Consumables Resupply System (OSCRS): Monopropellant application to space station and OMV automatic refueling impacts of an ELV launch, volume 4

NASA Technical Reports Server (NTRS)

1987-01-01

The use of orbital spacecraft consumables resupply system (OSCRS) at the Space Station is investigated, its use with the orbital maneuvering vehicle, and launch of the OSCRS on an expendable launch vehicles. A system requirements evaluation was performed initially to identify any unique requirements that would impact the design of OSCRS when used at the Space Station. Space Station documents were reviewed to establish requirements and to identify interfaces between the OSCRS, Shuttle, and Space Station, especially the Servicing Facility. The interfaces between OSCRS and the Shuttle consists of an avionics interface for command and control and a structural interface for launch support and for grappling with the Shuttle Remote Manipulator System. For use of the OSCRS at the Space Station, three configurations were evaluated using the results of the interface definition to increase the efficiency of OSCRS and to decrease the launch weight by Station-basing specific OSCRS subsystems. A modular OSCRS was developed in which the major subsystems were Station-based where possible. The configuration of an OSCRS was defined for transport of water to the Space Station.

Farming in space: environmental and biophysical concerns.

PubMed

Monje, O; Stutte, G W; Goins, G D; Porterfield, D M; Bingham, G E

2003-01-01

The colonization of space will depend on our ability to routinely provide for the metabolic needs (oxygen, water, and food) of a crew with minimal re-supply from Earth. On Earth, these functions are facilitated by the cultivation of plant crops, thus it is important to develop plant-based food production systems to sustain the presence of mankind in space. Farming practices on earth have evolved for thousands of years to meet both the demands of an ever-increasing population and the availability of scarce resources, and now these practices must adapt to accommodate the effects of global warming. Similar challenges are expected when earth-based agricultural practices are adapted for space-based agriculture. A key variable in space is gravity; planets (e.g. Mars, 1/3 g) and moons (e.g. Earth's moon, 1/6 g) differ from spacecraft orbiting the Earth (e.g. Space stations) or orbital transfer vehicles that are subject to microgravity. The movement of heat, water vapor, CO2 and O2 between plant surfaces and their environment is also affected by gravity. In microgravity, these processes may also be affected by reduced mass transport and thicker boundary layers around plant organs caused by the absence of buoyancy dependent convective transport. Future space farmers will have to adapt their practices to accommodate microgravity, high and low extremes in ambient temperatures, reduced atmospheric pressures, atmospheres containing high volatile organic carbon contents, and elevated to super-elevated CO2 concentrations. Farming in space must also be carried out within power-, volume-, and mass-limited life support systems and must share resources with manned crews. Improved lighting and sensor technologies will have to be developed and tested for use in space. These developments should also help make crop production in terrestrial controlled environments (plant growth chambers and greenhouses) more efficient and, therefore, make these alternative agricultural systems more economically feasible food production systems. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Why Deep Space Habitats Should Be Different from the International Space Station

NASA Technical Reports Server (NTRS)

Griffin, Brand; Brown, MacAulay

2016-01-01

It is tempting to view the International Space Station (ISS) as a model for deep space habitats. This is not a good idea for many reasons. The ISS does not have a habitation module; instead the individual crew quarters are dispersed across several modules, the galley is in the US Laboratory and the waste hygiene compartment is in a Node. This distributed arrangement may be inconvenient but more important differences distinguish a deep space habitat from the ISS. First, the Space Shuttle launch system that shaped, sized, and delivered most ISS elements has been retired. Its replacement, the Space Launch System (SLS), is specifically designed for human exploration beyond low-Earth orbit and is capable of transporting more efficient, large diameter, heavy-lift payloads. Next, because of the Earth's protective geomagnetic field, ISS crews are naturally shielded from lethal radiation. Deep space habitat designs must include either a storm shelter or strategically positioned equipment and stowage for radiation protection. Another important difference is the increased transit time with no opportunity for an ISS-type emergency return. It takes 7 to 10 days to go between Earth and cis-lunar locations and 1000 days for the Mars habitat transit. This long commute calls for greater crew autonomy with habitats designed for the crew to fix their own problems. The ISS rack-enclosed, densely packaged subsystems are a product of the Shuttle era and not maintenance friendly. A solution better suited for deep space habitats spreads systems out allowing direct access to single-layer packaging and providing crew access to each component without having to remove another. Operational readiness is another important discriminator. The ISS required over 100 flights to build, resupply, and transport the crew, whereas SLS offers the capability to launch a fully provisioned habitat that is operational without additional outfitting or resupply flights.

Farming in space: environmental and biophysical concerns

NASA Technical Reports Server (NTRS)

Monje, O.; Stutte, G. W.; Goins, G. D.; Porterfield, D. M.; Bingham, G. E.

2003-01-01

The colonization of space will depend on our ability to routinely provide for the metabolic needs (oxygen, water, and food) of a crew with minimal re-supply from Earth. On Earth, these functions are facilitated by the cultivation of plant crops, thus it is important to develop plant-based food production systems to sustain the presence of mankind in space. Farming practices on earth have evolved for thousands of years to meet both the demands of an ever-increasing population and the availability of scarce resources, and now these practices must adapt to accommodate the effects of global warming. Similar challenges are expected when earth-based agricultural practices are adapted for space-based agriculture. A key variable in space is gravity; planets (e.g. Mars, 1/3 g) and moons (e.g. Earth's moon, 1/6 g) differ from spacecraft orbiting the Earth (e.g. Space stations) or orbital transfer vehicles that are subject to microgravity. The movement of heat, water vapor, CO2 and O2 between plant surfaces and their environment is also affected by gravity. In microgravity, these processes may also be affected by reduced mass transport and thicker boundary layers around plant organs caused by the absence of buoyancy dependent convective transport. Future space farmers will have to adapt their practices to accommodate microgravity, high and low extremes in ambient temperatures, reduced atmospheric pressures, atmospheres containing high volatile organic carbon contents, and elevated to super-elevated CO2 concentrations. Farming in space must also be carried out within power-, volume-, and mass-limited life support systems and must share resources with manned crews. Improved lighting and sensor technologies will have to be developed and tested for use in space. These developments should also help make crop production in terrestrial controlled environments (plant growth chambers and greenhouses) more efficient and, therefore, make these alternative agricultural systems more economically feasible food production systems. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Farming in space: Environmental and biophysical concerns

NASA Astrophysics Data System (ADS)

Monje, O.; Stutte, G. W.; Goins, G. D.; Porterfield, D. M.; Bingham, G. E.

The colonization of space will depend on our ability to routinely provide for the metabolic needs (oxygen, water, and food) of a crew with minimal re-supply from Earth. On Earth, these functions are facilitated by the cultivation of plant crops, thus it is important to develop plant-based food production systems to sustain the presence of mankind in space. Farming practices on earth have evolved for thousands of years to meet both the demands of an ever-increasing population and the availability of scarce resources, and now these practices must adapt to accommodate the effects of global warming. Similar challenges are expected when earth-based agricultural practices are adapted for space-based agriculture. A key variable in space is gravity; planets (e.g. Mars, (1)/(3) g) and moons (e.g. Earth's moon, (1)/(6) g) differ from spacecraft orbiting the Earth (e.g. Space stations) or orbital transfer vehicles that are subject to microgravity. The movement of heat, water vapor, CO2 and O2 between plant surfaces and their environment is also affected by gravity. In microgravity, these processes may also be affected by reduced mass transport and thicker boundary layers around plant organs caused by the absence of buoyancy dependent convective transport. Future space farmers will have to adapt their practices to accommodate microgravity, high and low extremes in ambient temperatures, reduced atmospheric pressures, atmospheres containing high volatile organic carbon contents, and elevated to super-elevated CO2 concentrations. Farming in space must also be carried out within power-, volume-, and mass-limited life support systems and must share resources with manned crews. Improved lighting and sensor technologies will have to be developed and tested for use in space. These developments should also help make crop production in terrestrial controlled environments (plant growth chambers and greenhouses) more efficient and, therefore, make these alternative agricultural systems more economically feasible food production systems.

Transportation and platforms perspective

NASA Technical Reports Server (NTRS)

Bennett, Gary L.

1992-01-01

The topics covered are presented in viewgraph form and include the following: Office of Aeronautics and Space Technology; space research and technology (R&T); space R&T mission statement; Space R&T program development; R&T strategy; Office of Space Science and Applications (OSSA) technology needs; transportation technology; and space platforms technology.

14 CFR § 1214.302 - Background.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Background. § 1214.302 Section § 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 431.8 - Human space flight.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Human space flight. 431.8 Section 431.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.8 Human space flight...

14 CFR 431.8 - Human space flight.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Human space flight. 431.8 Section 431.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.8 Human space flight...

14 CFR 431.8 - Human space flight.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Human space flight. 431.8 Section 431.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.8 Human space flight...

14 CFR 431.8 - Human space flight.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Human space flight. 431.8 Section 431.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.8 Human space flight...

14 CFR 431.8 - Human space flight.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Human space flight. 431.8 Section 431.8 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.8 Human space flight...

The strategy of fusion genes construction determines efficient expression of introduced transcription factors.

PubMed

Adamus, Tomasz; Konieczny, Paweł; Sekuła, Małgorzata; Sułkowski, Maciej; Majka, Marcin

2014-01-01

The main goal in gene therapy and biomedical research is an efficient transcription factors (TFs) delivery system. SNAIL, a zinc finger transcription factor, is strongly involved in tumor, what makes its signaling pathways an interesting research subject. The necessity of tracking activation of intracellular pathways has prompted fluorescent proteins usage as localization markers. Advanced molecular cloning techniques allow to generate fusion proteins from fluorescent markers and transcription factors. Depending on fusion strategy, the protein expression levels and nuclear transport ability are significantly different. The P2A self-cleavage motif through its cleavage ability allows two single proteins to be simultaneously expressed. The aim of this study was to compare two strategies for introducing a pair of genes using expression vector system. We have examined GFP and SNAI1 gene fusions by comprising common nucleotide polylinker (multiple cloning site) or P2A motif in between them, resulting in one fusion or two independent protein expressions respectively. In each case transgene expression levels and translation efficiency as well as nuclear localization of expressed protein have been analyzed. Our data showed that usage of P2A motif provides more effective nuclear transport of SNAIL transcription factor than conventional genes linker. At the same time the fluorescent marker spreads evenly in subcellular space.

Engine Concept Study for an Advanced Single-Aisle Transport

NASA Technical Reports Server (NTRS)

Guynn, Mark D.; Berton, Jeffrey J.; Fisher, Kenneth L.; Haller, William J.; Tong, Michael; Thurman, Douglas R.

2009-01-01

The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turbofans, to today's high bypass ratio turbofans. Although increased bypass ratio has clear benefits in terms of propulsion system metrics such as specific fuel consumption, these benefits may not translate into aircraft system level benefits due to integration penalties. In this study, the design trade space for advanced turbofan engines applied to a single aisle transport (737/A320 class aircraft) is explored. The benefits of increased bypass ratio and associated enabling technologies such as geared fan drive are found to depend on the primary metrics of interest. For example, bypass ratios at which mission fuel consumption is minimized may not require geared fan technology. However, geared fan drive does enable higher bypass ratio designs which result in lower noise. The results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.

An Efficient Modelling Approach for Prediction of Porosity Severity in Composite Structures

NASA Technical Reports Server (NTRS)

Bedayat, Houman; Forghani, Alireza; Hickmott, Curtis; Roy, Martin; Palmieri, Frank; Grimsley, Brian; Coxon, Brian; Fernlund, Goran

2017-01-01

Porosity, as a manufacturing process-induced defect, highly affects the mechanical properties of cured composites. Multiple phenomena affect the formation of porosity during the cure process. Porosity sources include entrapped air, volatiles and off-gassing as well as bag and tool leaks. Porosity sinks are the mechanisms that contribute to reducing porosity, including gas transport, void shrinkage and collapse as well as resin flow into void space. Despite the significant progress in porosity research, the fundamentals of porosity in composites are not yet fully understood. The highly coupled multi-physics and multi-scale nature of porosity make it a complicated problem to predict. Experimental evidence shows that resin pressure history throughout the cure cycle plays an important role in the porosity of the cured part. Maintaining high resin pressure results in void shrinkage and collapse keeps volatiles in solution thus preventing off-gassing and bubble formation. This study summarizes the latest development of an efficient FE modeling framework to simulate the gas and resin transport mechanisms that are among the major phenomena contributing to porosity.

Axial inlet conversion to a centrifugal compressor with magnetic bearings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novecosky, T.

1994-01-01

NOVA's Alberta Gas Transmission Division transports natural gas via pipeline throughout the province of Alberta, Canada, exporting it to eastern Canada, US, and British Columbia. There is a continuing effort to operate the facilities and pipeline at the highest possible efficiency. One area being addressed to improve efficiency is compression of the gas. By improving compressor efficiency, fuel consumption and hence operating costs can be reduced. One method of improving compressor efficiency is by converting the compressor to an axial inlet configuration, a conversion that has been carried out more frequently in the past years. Concurrently, conventional hydrodynamic bearings havemore » been replaced with magnetic bearings on many centrifugal compressors. This paper discusses the design and installation for converting a radial overhung unit to an axial inlet configuration, having both magnetic bearings and a thrust reducer. The thrust reducer is required to reduce axial compressor shaft loads, to a level that allows the practical installation of magnetic bearings within the space limitations of the compressor (Bear and Gibson, 1992).« less

An efficient HZETRN (a galactic cosmic ray transport code)

NASA Technical Reports Server (NTRS)

Shinn, Judy L.; Wilson, John W.

1992-01-01

An accurate and efficient engineering code for analyzing the shielding requirements against the high-energy galactic heavy ions is needed. The HZETRN is a deterministic code developed at Langley Research Center that is constantly under improvement both in physics and numerical computation and is targeted for such use. One problem area connected with the space-marching technique used in this code is the propagation of the local truncation error. By improving the numerical algorithms for interpolation, integration, and grid distribution formula, the efficiency of the code is increased by a factor of eight as the number of energy grid points is reduced. The numerical accuracy of better than 2 percent for a shield thickness of 150 g/cm(exp 2) is found when a 45 point energy grid is used. The propagating step size, which is related to the perturbation theory, is also reevaluated.

2007 Research and Technology

NASA Technical Reports Server (NTRS)

Riddlebaugh, Stephen M. (Editor)

2008-01-01

The NASA Glenn Research Center is pushing the envelope of research and technology in aeronautics, space exploration, science, and space operations. Our research in aeropropulsion, structures and materials, and instrumentation and controls is enabling next-generation transportation systems that are faster, more environmentally friendly, more fuel efficient, and safer. Our research and development of space flight systems is enabling advanced power, propulsion, communications, and human health systems that will advance the exploration of our solar system. This report selectively summarizes NASA Glenn Research Center s research and technology accomplishments for fiscal year 2007. Comprising 104 short articles submitted by the staff scientists and engineers, the report is organized into six major sections: Aeropropulsion, Power and Space Propulsion, Communications, Space Processes and Experiments, Instrumentation and Controls, and Structures and Materials. It is not intended to be a comprehensive summary of all the research and technology work done over the past fiscal year; most of the work is reported in Glenn-published technical reports, journal articles, and presentations. For each article in this report, a Glenn contact person has been identified, and where possible, a reference document is listed so that additional information can be easily obtained.

Achievements of the DOT-NASA Joint Program on Remote Sensing and Spatial Information Technologies: Application to Multimodal Transportation

NASA Technical Reports Server (NTRS)

2002-01-01

This report presents three-year accomplishments from the national program on Commercial Remote Sensing and Geospatial Technology (CRSGT) application to transportation, administered by the U.S. Department of Transportation (U.S. DOT) in collaboration with the National Aeronautics and Space Administration (NASA). The joint program was authorized under Section 5113 of the Transportation Equity Act for the 21st Century (TEA-21). This is the first national program of its type focusing on transportation applications of emerging commercial remote sensing technologies. U.S. DOT's Research and Special Programs Administration manages the program in coordination with NASA's Earth Science Enterprise's application programs. The program focuses on applications of CRSGT products and systems for providing smarter and more efficient transportation operations and services. The program is performed in partnership with four major National Consortia for Remote Sensing in Transportation (NCRST). Each consortium focuses on research and development of products in one of the four priority areas for transportation application, and includes technical application and demonstration projects carried out in partnership with industries and service providers in their respective areas. The report identifies products and accomplishments from each of the four consortia in meeting the goal of providing smarter and more efficient transportation services. The products and results emerging from the program are being implemented in transportation operations and services through state and local agencies. The Environmental Assessment and Application Consortium (NCRST-E) provides leadership for developing and deploying cost effective environmental and transportation planning services, and integrates CRSGT advances for achieving smarter and cost effective corridor planning. The Infrastructure Management Consortium (NCRST-I) provides leadership in technologies that achieve smarter and cheaper ways of managing transportation infrastructure assets, operation, and inspection, and integrates CRSGT advances for achieving infrastructure security. The Traffic Flow Consortium (NCRST-F) provides leadership to develop new tools for regional traffic flow management including heavy vehicles and intermodal flow of freight, and integrates CRSGT advances for complementing and extending the reach of ITS user services. The Safety, Hazards and Disasters (NCRST-H) provides leadership for deploying remote sensing technology to locate transportation hazards and improve disaster recovery, and integrates CRSGT advances for application to protect transportation systems from terrorism. The DOT-NASA team is proud to present this report of accomplishments on products and results emerging from the joint program for application to transportation practice.

Transport: Introduction

NASA Technical Reports Server (NTRS)

Lewis, William; Rosenberg, Sanders D.

1992-01-01

Space transportation requirements for the NASA baseline scenario for future space missions are discussed. Spacecraft/propulsion technologies required for surface-to-orbit, orbit-to-orbit, and surface (lunar) transportation are addressed.

Indian space transportation programme: Near term outlook and issues for commercialisation

NASA Astrophysics Data System (ADS)

Nagendra, Narayan Prasad

2015-05-01

The Indian space transportation programme has grown from strength to strength with the launching of sounding rockets in the 60's to the development of heavy lift vehicles for telecommunication satellites in the present decade. With the growing market confidence in Indian Space Research Organisation's ability to reliably deliver payloads to low Earth orbit with its Polar Satellite Launch Vehicle, there is an inherent opportunity for India to cater to the commercial market. The present work assesses the current launch capacity of India in retrospect of international launches and provides India's outlook for the space transportation in the current decade. Launch capacity correlation with the requirements within the Indian space programme as well as the current space transportation infrastructure have been considered to identify bottlenecks in catering to the current national requirements alongside securing a greater market share in the international launch market. The state of commercialisation of launch vehicle development has been presented to provide an overview of policy and organisational issues for commercialisation of space transportation in India.

Phonon Mapping in Flowing Equilibrium

NASA Astrophysics Data System (ADS)

Ruff, J. P. C.

2015-03-01

When a material conducts heat, a modification of the phonon population occurs. The equilibrium Bose-Einstein distribution is perturbed towards flowing-equilibrium, for which the distribution function is not analytically known. Here I argue that the altered phonon population can be efficiently mapped over broad regions of reciprocal space, via diffuse x-ray scattering or time-of-flight neutron scattering, while a thermal gradient is applied across a single crystal sample. When compared to traditional transport measurements, this technique offers a superior, information-rich new perspective on lattice thermal conductivity, wherein the band and momentum dependences of the phonon thermal current are directly resolved. The proposed method is benchmarked using x-ray thermal diffuse scattering measurements of single crystal diamond under transport conditions. CHESS is supported by the NSF & NIH/NIGMS via NSF Award DMR-1332208.

Research and technology goals and objectives for Integrated Vehicle Health Management (IVHM)

NASA Technical Reports Server (NTRS)

1992-01-01

Integrated Vehicle Health Management (IVHM) is defined herein as the capability to efficiently perform checkout, testing, and monitoring of space transportation vehicles, subsystems, and components before, during, and after operational This includes the ability to perform timely status determination, diagnostics, and prognostics. IVHM must support fault-tolerant response including system/subsystem reconfiguration to prevent catastrophic failures; and IVHM must support the planning and scheduling of post-operational maintenance. The purpose of this document is to establish the rationale for IVHM and IVHM research and technology planning, and to develop technical goals and objectives. This document is prepared to provide a broad overview of IVHM for technology and advanced development activities and, more specifically, to provide a planning reference from an avionics viewpoint under the OAST Transportation Technology Program Strategic Plan.

Low lattice thermal conductivity of stanene

NASA Astrophysics Data System (ADS)

Peng, Bo; Zhang, Hao; Shao, Hezhu; Xu, Yuchen; Zhang, Xiangchao; Zhu, Heyuan

2016-02-01

A fundamental understanding of phonon transport in stanene is crucial to predict the thermal performance in potential stanene-based devices. By combining first-principle calculation and phonon Boltzmann transport equation, we obtain the lattice thermal conductivity of stanene. A much lower thermal conductivity (11.6 W/mK) is observed in stanene, which indicates higher thermoelectric efficiency over other 2D materials. The contributions of acoustic and optical phonons to the lattice thermal conductivity are evaluated. Detailed analysis of phase space for three-phonon processes shows that phonon scattering channels LA + LA/TA/ZA ↔ TA/ZA are restricted, leading to the dominant contributions of high-group-velocity LA phonons to the thermal conductivity. The size dependence of thermal conductivity is investigated as well for the purpose of the design of thermoelectric nanostructures.

Space transportation, satellite services, and space platforms

NASA Technical Reports Server (NTRS)

Disher, J. H.

1979-01-01

The paper takes a preview of the progressive development of vehicles for space transportation, satellite services, and orbital platforms. A low-thrust upper stage of either the ion engine or chemical type will be developed to transport large spacecraft and space platforms to and from GEO. The multimission spacecraft, space telescope, and other scientific platforms will require orbital serves going beyond that provided by the Shuttle's remote manipulator system, and plans call for extravehicular activity tools, improved remote manipulators, and a remote manned work station (the cherry picker).

Introduction to the Space Transportation System. [space shuttle cost effectiveness

NASA Technical Reports Server (NTRS)

Wilson, R. G.

1973-01-01

A new space transportation concept which is consistent with the need for more cost effective space operations has been developed. The major element of the Space Transportation System (STS) is the Space Shuttle. The rest of the system consists of a propulsive stage which can be carried within the space shuttle to obtain higher energy orbits. The final form of this propulsion stage will be called the Space Tug. A third important element, which is not actually a part of the STS since it has no propulsive capacity, is the Space Laboratory. The major element of the Space Shuttle is an aircraft-like orbiter which contains the crew, the cargo, and the liquid rocket engines in the rear.

Second Generation Reusable Launch Vehicle Development and Global Competitiveness of US Space Transportation Industry: Critical Success Factors Assessment

NASA Technical Reports Server (NTRS)

Enyinda, Chris I.

2002-01-01

In response to the unrelenting call in both public and private sectors fora to reduce the high cost associated with space transportation, many innovative partially or fully RLV (Reusable Launch Vehicles) designs (X-34-37) were initiated. This call is directed at all levels of space missions including scientific, military, and commercial and all aspects of the missions such as nonrecurring development, manufacture, launch, and operations. According to Wertz, tbr over thirty years, the cost of space access has remained exceedingly high. The consensus in the popular press is that to decrease the current astronomical cost of access to space, more safer, reliable, and economically viable second generation RLVs (SGRLV) must be developed. Countries such as Brazil, India, Japan, and Israel are now gearing up to enter the global launch market with their own commercial space launch vehicles. NASA and the US space launch industry cannot afford to lag behind. Developing SGRLVs will immeasurably improve the US's space transportation capabilities by helping the US to regain the global commercial space markets while supporting the transportation capabilities of NASA's space missions, Developing the SGRLVs will provide affordable commercial space transportation that will assure the competitiveness of the US commercial space transportation industry in the 21st century. Commercial space launch systems are having difficulty obtaining financing because of the high cost and risk involved. Access to key financial markets is necessary for commercial space ventures. However, public sector programs in the form of tax incentives and credits, as well as loan guarantees are not yet available. The purpose of this paper is to stimulate discussion and assess the critical success factors germane for RLVs development and US global competitiveness.

Parallel Monte Carlo transport modeling in the context of a time-dependent, three-dimensional multi-physics code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Procassini, R.J.

1997-12-31

The fine-scale, multi-space resolution that is envisioned for accurate simulations of complex weapons systems in three spatial dimensions implies flop-rate and memory-storage requirements that will only be obtained in the near future through the use of parallel computational techniques. Since the Monte Carlo transport models in these simulations usually stress both of these computational resources, they are prime candidates for parallelization. The MONACO Monte Carlo transport package, which is currently under development at LLNL, will utilize two types of parallelism within the context of a multi-physics design code: decomposition of the spatial domain across processors (spatial parallelism) and distribution ofmore » particles in a given spatial subdomain across additional processors (particle parallelism). This implementation of the package will utilize explicit data communication between domains (message passing). Such a parallel implementation of a Monte Carlo transport model will result in non-deterministic communication patterns. The communication of particles between subdomains during a Monte Carlo time step may require a significant level of effort to achieve a high parallel efficiency.« less

Buenos Aires - Toward Comprehensive Development and Sustainable Mobility

NASA Astrophysics Data System (ADS)

Kamrowska-Zaluska, Dorota

2017-10-01

This paper is introducing Buenos Aires’ achievements and challenges in implementing comprehensive development and integrating efficient and sustainable transport system within its urban structure. There are several important steps in this process starting from urban regeneration of Puerto Madero, the introduction and then implementation of a strategic plan Modelo territorial (2010) and of Buenos Aires’ Plan de Movilidad Sustentable (2013). The last one - Sustainable Mobility Plan helped Buenos Aires win several prestigious rewards for innovative approach to mobility and sustainable transport and leadership in combating climate change. Buenos Aires City government demonstrates strong leadership by implementing well-planned (Bus Rapid Transport) BRT solutions, stressing the importance of political will and support, flexibility and an open mind in listening to the points of view of all stakeholders involved. Buenos Aires has made a very important step toward sustainability by supporting development of more sustainable modes of transport, such as bicycle-sharing system and improving walkability of the city centre. The last initiative combined with strong focus on public spaces is adding to tourist attractiveness based on diversity of the capital of Argentina.

Preparing Texas' freight transportation system for 2055.

DOT National Transportation Integrated Search

2017-04-01

Efficient, reliable, and safe freight transportation is critical to the economic prosperity of any region. An efficient multimodal and intermodal transportation system reduces transportation and supply chain transaction costs and increases connectivi...

14 CFR 29.969 - Fuel tank expansion space.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel tank expansion space. 29.969 Section 29.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.969 Fuel tank expansion space...

14 CFR 29.969 - Fuel tank expansion space.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank expansion space. 29.969 Section 29.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.969 Fuel tank expansion space...

14 CFR 25.969 - Fuel tank expansion space.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank expansion space. 25.969 Section 25.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.969 Fuel tank expansion space...

14 CFR 29.969 - Fuel tank expansion space.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank expansion space. 29.969 Section 29.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.969 Fuel tank expansion space...

14 CFR 25.969 - Fuel tank expansion space.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank expansion space. 25.969 Section 25.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.969 Fuel tank expansion space...

14 CFR 25.969 - Fuel tank expansion space.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank expansion space. 25.969 Section 25.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.969 Fuel tank expansion space...

14 CFR 29.969 - Fuel tank expansion space.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank expansion space. 29.969 Section 29.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.969 Fuel tank expansion space...

14 CFR 25.969 - Fuel tank expansion space.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel tank expansion space. 25.969 Section 25.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.969 Fuel tank expansion space...

14 CFR 29.969 - Fuel tank expansion space.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank expansion space. 29.969 Section 29.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.969 Fuel tank expansion space...

14 CFR 25.969 - Fuel tank expansion space.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank expansion space. 25.969 Section 25.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.969 Fuel tank expansion space...

Electrical Power Systems for NASA's Space Transportation Program

NASA Technical Reports Server (NTRS)

Lollar, Louis F.; Maus, Louis C.

1998-01-01

Marshall Space Flight Center (MSFC) is the National Aeronautics and Space Administration's (NASA) lead center for space transportation systems development. These systems include earth to orbit launch vehicles, as well as vehicles for orbital transfer and deep space missions. The tasks for these systems include research, technology maturation, design, development, and integration of space transportation and propulsion systems. One of the key elements in any transportation system is the electrical power system (EPS). Every transportation system has to have some form of electrical power and the EPS for each of these systems tends to be as varied and unique as the missions they are supporting. The Preliminary Design Office (PD) at MSFC is tasked to perform feasibility analyses and preliminary design studies for new projects, particularly in the space transportation systems area. All major subsystems, including electrical power, are included in each of these studies. Three example systems being evaluated in PD at this time are the Liquid Fly Back Booster (LFBB) system, the Human Mission to Mars (HMM) study, and a tether based flight experiment called the Propulsive Small Expendable Deployer System (ProSEDS). These three systems are in various stages of definition in the study phase.

Project Aryavarta: A Novel approach in Innovative and energy efficient space transportation systems

NASA Astrophysics Data System (ADS)

Ghadawala, Rushi; Chokshi, Poojan; Verma, Rajeev

With the advancement of technology, there is a growing interest about other planets and so it would be necessary to shift the scientific analysis activities from the earth's orbit to that of other planets. The main aim of project ARYAVARTA is to shift a satellite orbit from one planet to another with the help of an Unmanned Space Vehicle (USV). For example, to shift scientific activities economically to other planets, we need to change the orbit of the satellite from earth to that of the other planet instead of sending separate space probes, as that would entail comparatively much higher cost. A solar powered USV is one that will be having ion propulsion system along with solar propulsion system. The USV, placed in rocket boosters, will be externally launched like a space shuttle to enable it to go beyond the atmospheric limit of the earth with sufficient escape velocity. Xenon cylinders attached to the USV will provide ion propulsion for furthering the mission. The USV will then be attached to the satellite revolving in the orbit of the earth. The satellite which is attached to the USV will be de-orbited with the help of xenon engines, and will be shifted to another orbit of another planet/satellite. Electricity generated by solar panels, made from multicrystalline solar cells, of the USV will be stored in the USV to help the mission/operational requirements. With the help of multireflectors, the reflected solar rays will be re-concentrated to the solar panel and hence, power efficiency will increase more than twice. Solar-electromagnetic propulsion would make such a mission possible because an ion engine can run almost continuously and outperform any chemical rocket for such long flights. This project will help to achieve higher efficiency with great economy, and eliminate the need for sending extra space probes for any other mission. As xenon engine occupies lesser room than conventional engines, more compact instruments will emerge ahead resulting in the overall reduction of the size and mass of the spacecraft, and thereby further increasing efficiency of the spacecraft.

49 CFR 176.168 - Transport of Class 1 (explosive) materials in vehicle spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Transport of Class 1 (explosive) materials in... REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Cargo Transport Units and Shipborne Barges § 176.168 Transport of Class 1 (explosive) materials in vehicle spaces. (a) All...

49 CFR 176.168 - Transport of Class 1 (explosive) materials in vehicle spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Transport of Class 1 (explosive) materials in... REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Cargo Transport Units and Shipborne Barges § 176.168 Transport of Class 1 (explosive) materials in vehicle spaces. (a) All...

Cavitating Jet Method and System for Oxygenation of Liquids

NASA Technical Reports Server (NTRS)

Chahine, Georges L.

2012-01-01

Reclamation and re-use of water is critical for space-based life support systems. A number of functions must be performed by any such system including removal of various contaminants and oxygenation. For long-duration space missions, this must be done with a compact, reliable system that requires little or no use of expendables and minimal power. DynaJets cavitating jets can oxidize selected organic compounds with much greater energy efficiency than ultrasonic devices typically used in sonochemistry. The focus of this work was to develop cavitating jets to simultaneously accomplish the functions of oxygenation and removal of contaminants of importance to space-structured water reclamation systems. The innovation is a method to increase the concentration of dissolved oxygen or other gasses in a liquid. It utilizes a particular form of novel cavitating jet operating at low to moderate pressures to achieve a high-efficiency means of transporting and mixing the gas into the liquid. When such a jet is utilized to simultaneously oxygenate the liquid and to oxidize organic compounds within the liquid, such as those in waste water, the rates of contaminant removal are increased. The invention is directed toward an increase in the dissolved gas content of a liquid, in general, and the dissolved oxygen content of a liquid in particular.

Dual redundant arm system operational quality measures and their applications - Dynamic measures

NASA Technical Reports Server (NTRS)

Lee, Sukhan; Kim, Sungbok

1990-01-01

Dual-arm dynamic operation quality measures are presented which quantify the efficiency and capability of generating Cartesian accelerations by two cooperative arms based on the analysis of dual-arm dynamic interactions. Dual-arm dynamic manipulability is defined as the efficiency of generating Cartesian accelerations under the dynamic and kinematic interactions between individual arms and an object under manipulation. The analysis of dual-arm dynamic interactions is based on the so-called Cartesian space agent model of an arm, which represents an individual arm as a force source acting upon a point mass with the effective Cartesian space arm dynamics and an environment or an object under manipulation. The Cartesian space agent model of an arm makes it possible to derive the dynamic and kinematic constraints involved in the transport, assembly and grasping modes of dual-arm cooperation. A task-oriented operational quality measure, (TOQd) is defined by evaluating dual-arm dynamic manipulability in terms of given task requirements. TOQd is used in dual-arm joint configuration optimization. Simulation results are shown. A complete set of forward dynamic equations for a dual-arm system is derived, and dual-arm dynamic operational quality measures for various modes of dual-arm cooperation allowing sliding contacts are established.

Point-to-point Commercial Space Transportation in the National Aviation System Final Report.

DOT National Transportation Integrated Search

2010-03-10

The advent of suborbital transport brings promise of point-to-point (PTP) long distance transportation as a revolutionary mode of air transportation. In 2008, the International Space University (ISU) of Strasbourg, France, published a report1 documen...

Future space transportation systems analysis study. Phase 1: Technical report, appendices. [a discussion of orbit transfer vehicles, lunar transport vehicles, space shuttles, and reusable spacecraft

NASA Technical Reports Server (NTRS)

1975-01-01

The transportation mass requirements developed for each mission and transportation mode were based on vehicle systems sized to fit the exact needs of each mission (i.e. rubber vehicles). The parametric data used to derive the mass requirements for each mission and transportation mode are presented to enable accommodation of possible changes in mode options or payload definitions. The vehicle sizing and functional requirements used to derive the parametric data will form the basis for conceptual configurations of the transportation elements in a later phase of study. An investigation of the weight growth approach to future space transportation systems analysis is presented. Parameters which affect weight growth, past weight histories, and the current state of future space-mission design are discussed. Weight growth factors of from 10 percent to 41 percent were derived for various missions or vehicles.

A space radiation transport method development

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

2004-01-01

Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest-order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard finite element method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 ms and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of re-configurable computing and could be utilized in the final design as verification of the deterministic method optimized design. Published by Elsevier Ltd on behalf of COSPAR.

Hybrid Power Management (HPM)

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2007-01-01

The NASA Glenn Research Center s Avionics, Power and Communications Branch of the Engineering and Systems Division initiated the Hybrid Power Management (HPM) Program for the GRC Technology Transfer and Partnership Office. HPM is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors and fuel cells. HPM has extremely wide potential. Applications include power generation, transportation systems, biotechnology systems, and space power systems. HPM has the potential to significantly alleviate global energy concerns, improve the environment, and stimulate the economy. One of the unique power devices being utilized by HPM for energy storage is the ultracapacitor. An ultracapacitor is an electrochemical energy storage device, which has extremely high volumetric capacitance energy due to high surface area electrodes, and very small electrode separation. Ultracapacitors are a reliable, long life, maintenance free, energy storage system. This flexible operating system can be applied to all power systems to significantly improve system efficiency, reliability, and performance. There are many existing and conceptual applications of HPM.

Application of Argonne's Glass Furnace Model to longhorn glass corporation oxy-fuel furnace for the production of amber glass.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golchert, B.; Shell, J.; Jones, S.

2006-09-06

The objective of this project is to apply the Argonne National Laboratory's Glass Furnace Model (GFM) to the Longhorn oxy-fuel furnace to improve energy efficiency and to investigate the transport of gases released from the batch/melt into the exhaust. The model will make preliminary estimates of the local concentrations of water, carbon dioxide, elemental oxygen, and other subspecies in the entire combustion space as well as the concentration of these species in the furnace exhaust gas. This information, along with the computed temperature distribution in the combustion space may give indications on possible locations of crown corrosion. An investigation intomore » the optimization of the furnace will be performed by varying several key parameters such as the burner firing pattern, exhaust number/size, and the boost usage (amount and distribution). Results from these parametric studies will be analyzed to determine more efficient methods of operating the furnace that reduce crown corrosion. Finally, computed results from the GFM will be qualitatively correlated to measured values, thus augmenting the validation of the GFM.« less

Conceptual designs study for a Personnel Launch System (PLS)

NASA Technical Reports Server (NTRS)

Wetzel, E. D.

1990-01-01

A series of conceptual designs for a manned, Earth to Low Earth Orbit transportation system was developed. Non-winged, low L/D vehicle shapes are discussed. System and subsystem trades emphasized safety, operability, and affordability using near-term technology. The resultant conceptual design includes lessons learned from commercial aviation that result in a safe, routine, operationally efficient system. The primary mission for this Personnel Launch System (PLS) would be crew rotation to the SSF; other missions, including satellite servicing, orbital sortie, and space rescue were also explored.

Solar power satellite system definition study. Part 1 and part 2, volume 2: Technical summary

NASA Technical Reports Server (NTRS)

1977-01-01

Practical designs for power transmission were developed to meet requirements and constraints. Microwave link error was analyzed to confirm attainability of acceptable link efficiency. Silicon photovoltaic was determined to be the best overall choice for energy conversion, with a potassium Rankine cycle as the backup choice. Space transportation operations provide low cost because of traffic level, and the payload volume is the launch vehicle design driver. The power cost is 4 to 5 /kwh, which will be competitive with fossil fuel sources by the year 2000.

Space shuttle. [a transportation system for low orbit space missions

NASA Technical Reports Server (NTRS)

1974-01-01

The space shuttle is discussed as a reusable space vehicle operated as a transportation system for space missions in low earth orbit. Space shuttle studies and operational capabilities are reported for potential missions indicating that about 38 percent are likely to be spacelab missions with the remainder being the replacement, revisit, or retrieval of automated spacecraft.

Economic analysis of the space shuttle system, volume 1

NASA Technical Reports Server (NTRS)

1972-01-01

An economic analysis of the space shuttle system is presented. The analysis is based on economic benefits, recurring costs, non-recurring costs, and ecomomic tradeoff functions. The most economic space shuttle configuration is determined on the basis of: (1) objectives of reusable space transportation system, (2) various space transportation systems considered and (3) alternative space shuttle systems.

14 CFR 406.111 - Signing documents.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Signing documents. 406.111 Section 406.111 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURE INVESTIGATIONS, ENFORCEMENT, AND ADMINISTRATIVE REVIEW Rules of Practice in FAA Space...

14 CFR 406.111 - Signing documents.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Signing documents. 406.111 Section 406.111 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURE INVESTIGATIONS, ENFORCEMENT, AND ADMINISTRATIVE REVIEW Rules of Practice in FAA Space...

The National Space Transportation Policy : Issues for Congress

DOT National Transportation Integrated Search

1995-05-01

In responding to the political and military challenges of the Cold War, and the urge to explore and exploit outer space, the United States developed a capable fleet of space transportation systems for carrying cargo and people into space. Increasing ...

Parameter estimation uncertainty: Comparing apples and apples?

NASA Astrophysics Data System (ADS)

Hart, D.; Yoon, H.; McKenna, S. A.

2012-12-01

Given a highly parameterized ground water model in which the conceptual model of the heterogeneity is stochastic, an ensemble of inverse calibrations from multiple starting points (MSP) provides an ensemble of calibrated parameters and follow-on transport predictions. However, the multiple calibrations are computationally expensive. Parameter estimation uncertainty can also be modeled by decomposing the parameterization into a solution space and a null space. From a single calibration (single starting point) a single set of parameters defining the solution space can be extracted. The solution space is held constant while Monte Carlo sampling of the parameter set covering the null space creates an ensemble of the null space parameter set. A recently developed null-space Monte Carlo (NSMC) method combines the calibration solution space parameters with the ensemble of null space parameters, creating sets of calibration-constrained parameters for input to the follow-on transport predictions. Here, we examine the consistency between probabilistic ensembles of parameter estimates and predictions using the MSP calibration and the NSMC approaches. A highly parameterized model of the Culebra dolomite previously developed for the WIPP project in New Mexico is used as the test case. A total of 100 estimated fields are retained from the MSP approach and the ensemble of results defining the model fit to the data, the reproduction of the variogram model and prediction of an advective travel time are compared to the same results obtained using NSMC. We demonstrate that the NSMC fields based on a single calibration model can be significantly constrained by the calibrated solution space and the resulting distribution of advective travel times is biased toward the travel time from the single calibrated field. To overcome this, newly proposed strategies to employ a multiple calibration-constrained NSMC approach (M-NSMC) are evaluated. Comparison of the M-NSMC and MSP methods suggests that M-NSMC can provide a computationally efficient and practical solution for predictive uncertainty analysis in highly nonlinear and complex subsurface flow and transport models. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Next generation: In-space transportation system(s)

NASA Technical Reports Server (NTRS)

Huffaker, Fredrick; Redus, Jerry; Kelley, David L.

1991-01-01

The development of the next generation In-Space Transportation System presents a unique challenge to the design of a propulsion system for the Space Exploration Initiative (SEI). Never before have the requirements for long-life, multiple mission use, space basing, high reliability, man-rating, and minimum maintenance come together with performance in one system that must protect the lives of space travelers, support the mission logistics needs, and do so at an acceptable cost. The challenge that is presented is to quantify the bounds of these requirements. The issue is one of degree. The length of acceptable life in space, the time it takes for reuse to pay off, and the degree to which space basing is practical (full, partial, or expended) are the issues that determine the reusable bounds of a design and include dependability, contingency capabilities, resilency, and minimum dependence on a maintenance node in preparation for and during a mission. Missions to planet earth, other non-NASA missions, and planetary missions will provide important but less demanding requirements for the transportation systems of the future. The mission proposed for the SEI require a family of transportation vehicles to meet the requirements for establishing a permanent human presence on the Moon and eventually on Mars. Specialized vehicles are needed to accomplish the different phases of each mission. These large scale missions require assembly in space and will provide the greatest usage of the planned integrated transportation system. The current approach to defining the In-Space Transportation System for the SEI Moon missions with later Mars mission applications is presented. Several system development options, propulsion concepts, current/proposed activities are reviewed, and key propulsion design criteria, issues, and technology challenges for the next generation In-Space Transportation System(s) are outlined.

14 CFR 223.3 - Mandatory free transportation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Mandatory free transportation. 223.3 Section 223.3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS FREE AND REDUCED-RATE TRANSPORTATION General Provisions § 223.3 Mandatory...

14 CFR 206.1 - Emergency transportation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Emergency transportation. 206.1 Section 206.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS... EXEMPTIONS § 206.1 Emergency transportation. Notwithstanding the provisions of section 41101 of the Statute...

14 CFR 206.1 - Emergency transportation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Emergency transportation. 206.1 Section 206.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS... EXEMPTIONS § 206.1 Emergency transportation. Notwithstanding the provisions of section 41101 of the Statute...

14 CFR 206.1 - Emergency transportation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Emergency transportation. 206.1 Section 206.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS... EXEMPTIONS § 206.1 Emergency transportation. Notwithstanding the provisions of section 41101 of the Statute...

14 CFR 206.1 - Emergency transportation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Emergency transportation. 206.1 Section 206.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS... EXEMPTIONS § 206.1 Emergency transportation. Notwithstanding the provisions of section 41101 of the Statute...

14 CFR 223.3 - Mandatory free transportation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Mandatory free transportation. 223.3 Section 223.3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS FREE AND REDUCED-RATE TRANSPORTATION General Provisions § 223.3 Mandatory...

14 CFR 223.3 - Mandatory free transportation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Mandatory free transportation. 223.3 Section 223.3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS FREE AND REDUCED-RATE TRANSPORTATION General Provisions § 223.3 Mandatory...

14 CFR 223.3 - Mandatory free transportation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Mandatory free transportation. 223.3 Section 223.3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS FREE AND REDUCED-RATE TRANSPORTATION General Provisions § 223.3 Mandatory...

NASA Exploration Team (NExT) In-Space Transportation Overview

NASA Technical Reports Server (NTRS)

Drake, Bret G.; Cooke, Douglas R.; Kos, Larry D.; Brady, Hugh J. (Technical Monitor)

2002-01-01

This presentation provides an overview of NASA Exploration Team's (NEXT) vision of in-space transportation in the future. Hurdles facing in-space transportation include affordable power sources, crew health and safety, optimized robotic and human operations and space systems performance. Topics covered include: exploration of Earth's neighborhood, Earth's neighborhood architecture and elements, Mars mission trajectory options, delta-v variations, Mars mission duration options, Mars mission architecture, nuclear electric propulsion advantages and miscellaneous technology needs.

Space Transportation System Payloads Data and Analysis

NASA Technical Reports Server (NTRS)

Peterson, J. D.; Craft, H. G., Jr.

1975-01-01

The background, current developments and future plans for the Space Transportation System Payloads Data and Analysis (SPDA) activities at Marshall Space Flight Center are reviewed. It is shown how the payload data bank and future planned activities will interface with the payloads community and Space Transportation System designers. The interfaces with the STS data base include NASA planning, international planning, payload design, shuttle design, user agencies planning and information, and OMB, Congress and others.

Resonance controlled transport in phase space

NASA Astrophysics Data System (ADS)

Leoncini, Xavier; Vasiliev, Alexei; Artemyev, Anton

2018-02-01

We consider the mechanism of controlling particle transport in phase space by means of resonances in an adiabatic setting. Using a model problem describing nonlinear wave-particle interaction, we show that captures into resonances can be used to control transport in momentum space as well as in physical space. We design the model system to provide creation of a narrow peak in the distribution function, thus producing effective cooling of a sub-ensemble of the particles.

PROTEUS-SN User Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shemon, Emily R.; Smith, Micheal A.; Lee, Changho

2016-02-16

PROTEUS-SN is a three-dimensional, highly scalable, high-fidelity neutron transport code developed at Argonne National Laboratory. The code is applicable to all spectrum reactor transport calculations, particularly those in which a high degree of fidelity is needed either to represent spatial detail or to resolve solution gradients. PROTEUS-SN solves the second order formulation of the transport equation using the continuous Galerkin finite element method in space, the discrete ordinates approximation in angle, and the multigroup approximation in energy. PROTEUS-SN’s parallel methodology permits the efficient decomposition of the problem by both space and angle, permitting large problems to run efficiently on hundredsmore » of thousands of cores. PROTEUS-SN can also be used in serial or on smaller compute clusters (10’s to 100’s of cores) for smaller homogenized problems, although it is generally more computationally expensive than traditional homogenized methodology codes. PROTEUS-SN has been used to model partially homogenized systems, where regions of interest are represented explicitly and other regions are homogenized to reduce the problem size and required computational resources. PROTEUS-SN solves forward and adjoint eigenvalue problems and permits both neutron upscattering and downscattering. An adiabatic kinetics option has recently been included for performing simple time-dependent calculations in addition to standard steady state calculations. PROTEUS-SN handles void and reflective boundary conditions. Multigroup cross sections can be generated externally using the MC2-3 fast reactor multigroup cross section generation code or internally using the cross section application programming interface (API) which can treat the subgroup or resonance table libraries. PROTEUS-SN is written in Fortran 90 and also includes C preprocessor definitions. The code links against the PETSc, METIS, HDF5, and MPICH libraries. It optionally links against the MOAB library and is a part of the SHARP multi-physics suite for coupled multi-physics analysis of nuclear reactors. This user manual describes how to set up a neutron transport simulation with the PROTEUS-SN code. A companion methodology manual describes the theory and algorithms within PROTEUS-SN.« less

Empirical study on a directed and weighted bus transport network in China

NASA Astrophysics Data System (ADS)

Feng, Shumin; Hu, Baoyu; Nie, Cen; Shen, Xianghao

2016-01-01

Bus transport networks are directed complex networks that consist of routes, stations, and passenger flow. In this study, the concept of duplication factor is introduced to analyze the differences between uplinks and downlinks for the bus transport network of Harbin (BTN-H). Further, a new representation model for BTNs is proposed, named as directed-space P. Two empirical characteristics of BTN-H are reported in this paper. First, the cumulative distributions of weighted degree, degree, number of routes that connect to each station, and node weight (peak-hour trips at a station) uniformly follow the exponential law. Meanwhile, the node weight shows positive correlations with the corresponding weighted degree, degree, and number of routes that connect to a station. Second, a new richness parameter of a node is explored by its node weight and the connectivity, weighted connectivity, average shortest path length and efficiency between rich nodes can be fitted by composite exponential functions to demonstrate the rich-club phenomenon.

Advanced Air Transportation Technologies Project, Final Document Collection

NASA Technical Reports Server (NTRS)

Mogford, Richard H.; Wold, Sheryl (Editor)

2008-01-01

This CD ROM contains a compilation of the final documents of the Advanced Air Transportation Technologies (AAIT) project, which was an eight-year (1996 to 2004), $400M project managed by the Airspace Systems Program office, which was part of the Aeronautics Research Mission Directorate at NASA Headquarters. AAIT focused on developing advanced automation tools and air traffic management concepts that would help improve the efficiency of the National Airspace System, while maintaining or enhancing safety. The documents contained in the CD are final reports on AAIT tasks that serve to document the project's accomplishments over its eight-year term. Documents include information on: Advanced Air Transportation Technologies, Autonomous Operations Planner, Collaborative Arrival Planner, Distributed Air/Ground Traffic Management Concept Elements 5, 6, & 11, Direct-To, Direct-To Technology Transfer, Expedite Departure Path, En Route Data Exchange, Final Approach Spacing Tool - (Active and Passive), Multi-Center Traffic Management Advisor, Multi Center Traffic Management Advisor Technology Transfer, Surface Movement Advisor, Surface Management System, Surface Management System Technology Transfer and Traffic Flow Management Research & Development.

[The development of a portable life support device for transporting pre-hospital critically ill patients].

PubMed

Song, Zhen-xing; Wu, Tai-hu; Meng, Xing-ju; Lu, Heng-zhi; Zheng, Jie-wen; Wang, Hai-tao

2012-06-01

To describe a portable life support device for transportation of pre-hospital patients with critical illness. The characteristics and requirements for urgent management during transportation of critically ill patients to a hospital were analyzed. With adoption of the original equipment, with the aid of staple of the art soft ware, the overall structure, its installation, fixation, freedom from interference, operational function were studied, and the whole system of life support and resuscitation was designed. The system was composed by different modules, including mechanical ventilation, transfusion, aspiration, critical care, oxygen supply and power supply parts. The system could be fastened quickly to a stretcher to form portable intensive care unit (ICU), and it could be carried by different size vehicles to provide nonstop treatment by using power supply of the vehicle, thus raising the efficiency of urgent care. With characteristics of its small size, lightweight and portable, the device is particularly suitable for narrow space and extreme environment.

Suspension cell culture in microgravity and development of a space bioreactor

NASA Technical Reports Server (NTRS)

Morrison, Dennis R.

1987-01-01

NASA has methodically developed unique suspension type cell and recovery apparatus culture systems for bioprocess technology experiments and production of biological products in microgravity. The first space bioreactor has been designed for microprocessor control, no gaseous headspace, circulation and resupply of culture medium, and slow mixing in very low shear regimes. Various ground based bioreactors are being used to test reactor vessel design, on-line sensors, effects of shear, nutrient supply, and waste removal from continuous culture of human cells attached to microcarriers. The small (500 ml) bioreactor is being constructed for flight experiments in the Shuttle middeck to verify systems operation under microgravity conditions and to measure the efficiencies of mass transport, gas transfer, oxygen consumption, and control of low shear stress on cells.

Influence of structural dynamics on vehicle design - Government view. [of aerospace vehicles

NASA Technical Reports Server (NTRS)

Kordes, E. E.

1977-01-01

Dynamic design considerations for aerospace vehicles are discussed, taking into account fixed wing aircraft, rotary wing aircraft, and launch, space, and reentry vehicles. It is pointed out that space vehicles have probably had the most significant design problems from the standpoint of structural dynamics, because their large lightweight structures are highly nonlinear. Examples of problems in the case of conventional aircraft include the flutter encountered by high performance military aircraft with external stores. A description is presented of a number of examples which illustrate the direction of present efforts for improving aircraft efficiency. Attention is given to the results of studies on the structural design concepts for the arrow-wing supersonic cruise aircraft configuration and a system study on low-wing-loading, short haul transports.

Efficient Mobility Summit: Transportation and the Future of Dynamic Mobility Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-12-01

On October 27, 2015, The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) brought together local and national thought leaders to discuss the convergence of connectivity, vehicle automation, and transportation infrastructure investments at the Future Energy Efficient Mobility Workshop. The half-day workshop was held in conjunction with the Colorado Department of Transportation's (CDOT) Transportation Matters Summit and featured four panel sessions that showcased perspectives on efficient mobility from federal and state agencies, automakers and their suppliers, transportation data providers, and freight companies. This summary provides highlights from the meeting's exchanges of ideas and existing applications. Transportation's (CDOT) Transportation Mattersmore » Summit and featured four panel sessions that showcased perspectives on efficient mobility from federal and state agencies, automakers and their suppliers, transportation data providers, and freight companies. This summary provides highlights from the meeting's exchanges of ideas and existing applications.« less