Vertical integration from the large Hilbert space

NASA Astrophysics Data System (ADS)

Erler, Theodore; Konopka, Sebastian

2017-12-01

We develop an alternative description of the procedure of vertical integration based on the observation that amplitudes can be written in BRST exact form in the large Hilbert space. We relate this approach to the description of vertical integration given by Sen and Witten.

NASA space station automation: AI-based technology review

NASA Technical Reports Server (NTRS)

Firschein, O.; Georgeff, M. P.; Park, W.; Neumann, P.; Kautz, W. H.; Levitt, K. N.; Rom, R. J.; Poggio, A. A.

1985-01-01

Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures.

Large antenna experiments aboard the space shuttle: Application of nonuniform sampling techniques

NASA Technical Reports Server (NTRS)

Rahmatsamii, Y.

1988-01-01

Future satellite communication and scientific spacecraft will utilize antennas with dimensions as large as 20 meters. In order to commercially use these large, low sidelobe and multiple beam antennas, a high level of confidence must be established as to their performance in the 0-g and space environment. Furthermore, it will be desirable to demonstrate the applicability of surface compensation techniques for slowly varying surface distortions which could result from thermal effects. An overview of recent advances in performing RF measurements on large antennas is presented with emphasis given to the application of a space based far-field range utilizing the Space Shuttle and the concept of a newly developed nonuniform sampling technique.

Evaluating the uniformity of color spaces and performance of color difference formulae

NASA Astrophysics Data System (ADS)

Lian, Yusheng; Liao, Ningfang; Wang, Jiajia; Tan, Boneng; Liu, Zilong

2010-11-01

Using small color difference data sets (Macadam ellipses dataset and RIT-DuPont suprathreshold color difference ellipses dataset), and large color difference data sets (Munsell Renovation Data and OSA Uniform Color Scales dataset), the uniformity of several color spaces and performance of color difference formulae based on these color spaces are evaluated. The color spaces used are CIELAB, DIN99d, IPT, and CIECAM02-UCS. It is found that the uniformity of lightness is better than saturation and hue. Overall, for all these color spaces, the uniformity in the blue area is inferior to the other area. The uniformity of CIECAM02-UCS is superior to the other color spaces for the whole color-difference range from small to large. The uniformity of CIELAB and IPT for the large color difference data sets is better than it for the small color difference data sets, but the DIN99d is opposite. Two common performance factors (PF/3 and STRESS) and the statistical F-test are calculated to test the performance of color difference formula. The results show that the performance of color difference formulae based on these four color spaces is consistent with the uniformity of these color spaces.

Space Construction Automated Fabrication Experiment Definition Study (SCAFEDS), part 3. Volume 3: Requirements

NASA Technical Reports Server (NTRS)

1979-01-01

The performance, design and verification requirements for the space Construction Automated Fabrication Experiment (SCAFE) are defined. The SCAFE program defines, develops, and demonstrates the techniques, processes, and equipment required for the automatic fabrication of structural elements in space and for the assembly of such elements into a large, lightweight structure. The program defines a large structural platform to be constructed in orbit using the space shuttle as a launch vehicle and construction base.

Utilization of lunar materials and expertise for large scale operations in space: Abstracts. [lunar bases and space industrialization

NASA Technical Reports Server (NTRS)

Criswell, D. R. (Editor)

1976-01-01

The practicality of exploiting the moon, not only as a source of materials for large habitable structures at Lagrangian points, but also as a base for colonization is discussed in abstracts of papers presented at a special session on lunar utilization. Questions and answers which followed each presentation are included after the appropriate abstract. Author and subject indexes are provided.

Computational methods and software systems for dynamics and control of large space structures

NASA Technical Reports Server (NTRS)

Park, K. C.; Felippa, C. A.; Farhat, C.; Pramono, E.

1990-01-01

Two key areas of crucial importance to the computer-based simulation of large space structures are discussed. The first area involves multibody dynamics (MBD) of flexible space structures, with applications directed to deployment, construction, and maneuvering. The second area deals with advanced software systems, with emphasis on parallel processing. The latest research thrust in the second area involves massively parallel computers.

The data array, a tool to interface the user to a large data base

NASA Technical Reports Server (NTRS)

Foster, G. H.

1974-01-01

Aspects of the processing of spacecraft data is considered. Use of the data array in a large address space as an intermediate form in data processing for a large scientific data base is advocated. Techniques for efficient indexing in data arrays are reviewed and the data array method for mapping an arbitrary structure onto linear address space is shown. A compromise between the two forms is given. The impact of the data array on the user interface are considered along with implementation.

Large space-based systems for dealing with global environment change

NASA Technical Reports Server (NTRS)

Jenkins, Lyle M.

1992-01-01

Increased concern over the effects of global climate change and depletion of the ozone layer has resulted in support for the Global Change Research Program and the Mission to Planet Earth. Research to understand Earth system processes is critical, but it falls short of providing ways of mitigating the effects of change. Geoengineering options and alternatives to interactively manage change need to be developed. Space-based concepts for dealing with changes to the environment should be considered in addition to Earth-based actions. 'Mission for Planet Earth' describes those space-based geoengineering solutions that may combine with an international global change program to stabilize the Global environment. Large space systems that may be needed for this response challenge guidance and control engineering and technology. Definition, analysis, demonstration, and preparation of geoengineering technology will provide a basis for policy response if global change consequences are severe.

Piezoelectric Polymers Actuators for Precise Shape Control of Large Scale Space Antennas

NASA Technical Reports Server (NTRS)

Chen, Qin; Natale, Don; Neese, Bret; Ren, Kailiang; Lin, Minren; Zhang, Q. M.; Pattom, Matthew; Wang, K. W.; Fang, Houfei; Im, Eastwood

2007-01-01

Extremely large, lightweight, in-space deployable active and passive microwave antennas are demanded by future space missions. This paper investigates the development of PVDF based piezopolymer actuators for controlling the surface accuracy of a membrane reflector. Uniaxially stretched PVDF films were poled using an electrodeless method which yielded high quality poled piezofilms required for this application. To further improve the piezoperformance of piezopolymers, several PVDF based copolymers were examined. It was found that one of them exhibits nearly three times improvement in the in-plane piezoresponse compared with PVDF and P(VDF-TrFE) piezopolymers. Preliminary experimental results indicate that these flexible actuators are very promising in controlling precisely the shape of the space reflectors.

Prime focus architectures for large space telescopes: reduce surfaces to save cost

NASA Astrophysics Data System (ADS)

Breckinridge, J. B.; Lillie, C. F.

2016-07-01

Conceptual architectures are now being developed to identify future directions for post JWST large space telescope systems to operate in the UV Optical and near IR regions of the spectrum. Here we show that the cost of optical surfaces within large aperture telescope/instrument systems can exceed $100M/reflection when expressed in terms of the aperture increase needed to over come internal absorption loss. We recommend a program in innovative optical design to minimize the number of surfaces by considering multiple functions for mirrors. An example is given using the Rowland circle imaging spectrometer systems for UV space science. With few exceptions, current space telescope architectures are based on systems optimized for ground-based astronomy. Both HST and JWST are classical "Cassegrain" telescopes derived from the ground-based tradition to co-locate the massive primary mirror and the instruments at the same end of the metrology structure. This requirement derives from the dual need to minimize observatory dome size and cost in the presence of the Earth's 1-g gravitational field. Space telescopes, however function in the zero gravity of space and the 1- g constraint is relieved to the advantage of astronomers. Here we suggest that a prime focus large aperture telescope system in space may have potentially have higher transmittance, better pointing, improved thermal and structural control, less internal polarization and broader wavelength coverage than Cassegrain telescopes. An example is given showing how UV astronomy telescopes use single optical elements for multiple functions and therefore have a minimum number of reflections.

Design of a large dual polarized Ku band reflectarray for space borne radar altimeter

NASA Technical Reports Server (NTRS)

Hodges, Richard E.; Zawadzki, Mark

2004-01-01

We describe the design of a large dual-beam, dual polarized reflectarray designed for a space-based radar altimeter. This application requires a 2.16 X 0.35 m aperture that can be folded for launch stowage. Low mass and >50% efficiency are also required. A reflectarray antenna offers the best approach but also presents unique technical challenges since a reflectarry has never been used in a space based radar application. In what follows, we describe the design, analysis and measurements of a breadboard test array built to demonstrate the reflectarray concept.

The first products made in space: Monodisperse latex particles

NASA Technical Reports Server (NTRS)

Vanderhoff, J. W.; El-Aasser, M. S.; Micale, F. J.; Sudol, E. D.; Tseng, C.-M.; Sheu, H.-R.; Kornfeld, D. M.

1988-01-01

The preparation of large particle size 3 to 30 micrometer monodisperse latexes in space confirmed that original rationale unequivocally. The flight polymerizations formed negligible amounts of coagulum as compared to increasing amounts for the ground-based polymerizations. The number of offsize large particles in the flight latexes was smaller than in the ground-based latexes. The particle size distribution broadened and more larger offsize particles were formed when the polymerizations of the partially converted STS-4 latexes were completed on Earth. Polymerization in space also showed other unanticipated advantages. The flight latexes had narrower particle size distributions than the ground-based latexes. The particles of the flight latexes were more perfect spheres than those of the ground-based latexes. The superior uniformity of the flight latexes was confirmed by the National Bureau of Standards acceptance of the 10 micrometer STS-6 latex and the 30 micrometer STS-11 latexes as Standard Reference Materials, the first products made in space for sale on Earth. The polymerization rates in space were the same as those on Earth within experimental error. Further development of the ground-based polymerization recipes gave monodisperse particles as large as 100 micrometer with tolerable levels of coagulum, but their uniformity was significantly poorer than the flight latexes. Careful control of the polymerization parameters gave uniform nonspherical particles: symmetrical and asymmetrical doublets, ellipsoids, egg-shaped, ice cream cone-shaped, and popcorn-shaped particles.

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...

Systems definition study for shuttle demonstration flights of large space structures, Volume 2: Technical Report

NASA Technical Reports Server (NTRS)

1979-01-01

The development of large space structure (LSS) technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. It is concluded that an LSS flight demonstration using an Automated Beam Builder and the orbiter as a construction base, could be performed in the 1983-1984 time period. The estimated cost is $24 million exclusive of shuttle launch costs. During the mission, a simple space platform could be constructed in-orbit to accommodate user requirements associated with earth viewing and materials exposure experiments needs.

Recent literature on structural modeling, identification, and analysis

NASA Technical Reports Server (NTRS)

Craig, Roy R., Jr.

1990-01-01

The literature on the mathematical modeling of large space structures is first reviewed, with attention given to continuum models, model order reduction, substructuring, and computational techniques. System identification and mode verification are then discussed with reference to the verification of mathematical models of large space structures. In connection with analysis, the paper surveys recent research on eigensolvers and dynamic response solvers for large-order finite-element-based models.

Silicon nitride ceramic development in Thales Alenia Space : qualification achievement and further developments for future applications

NASA Astrophysics Data System (ADS)

Cornillon, L.; Devilliers, C.; Behar-Lafenetre, S.; Ait-Zaid, S.; Berroth, K.; Bravo, A. C.

2017-11-01

Dealing with ceramic materials for more than two decades, Thales Alenia Space - France has identified Silicon Nitride Si3N4 as a high potential material for the manufacturing of stiff, stable and lightweight truss structure for future large telescopes. Indeed, for earth observation or astronomic observation, space mission requires more and more telescopes with high spatial resolution, which leads to the use of large primary mirrors, and a long distance between primary and secondary mirrors. Therefore current and future large space telescopes require a huge truss structure to hold and locate precisely the mirrors. Such large structure requires very strong materials with high specific stiffness and a low coefficient of thermal expansion (CTE). Based on the silicon nitride performances and on the know how of FCT Ingenieurkeramik to manufacture complex parts, Thales Alenia Space (TAS) has engaged, in cooperation with FCT, activities to develop and qualify silicon nitride parts for other applications for space projects.

Silicon nitride ceramic development in Thales Alenia Space: qualification achiement and further developments for future applications

NASA Astrophysics Data System (ADS)

Cornillon, L.; Devilliers, C.; Behar-Lafenetre, S.; Ait-Zaid, S.; Berroth, K.; Bravo, A. C.

2017-11-01

Dealing with ceramic materials for more than two decades, Thales Alenia Space - France has identified Silicon Nitride Si3N4 as a high potential material for the manufacturing of stiff, stable and lightweight truss structure for future large telescopes. Indeed, for earth observation or astronomic observation, space mission requires more and more telescopes with high spatial resolution, which leads to the use of large primary mirrors, and a long distance between primary and secondary mirrors. Therefore current and future large space telescopes require a huge truss structure to hold and locate precisely the mirrors. Such large structure requires very strong materials with high specific stiffness and a low coefficient of thermal expansion (CTE). Based on the silicon nitride performances and on the know how of FCT Ingenieurkeramik to manufacture complex parts, Thales Alenia Space (TAS) has engaged, in cooperation with FCT, activities to develop and qualify silicon nitride parts for other applications for space projects.

Radiation shielding for deep space manned missions by cryogen free superconducting magnets.

NASA Astrophysics Data System (ADS)

Spillantini, Piero

In last years some activity was dedicated to the solution of the following problem: can be artificially created, around a space vehicle in a manned interplanetary travel or around a manned `space base' in deep space, a magnetic field approaching as much as possible the terrestrial one in terms of bending power on the arriving particles? Preliminary evaluations for active shielding based on superconducting magnets were made a few years ago in ESA supported studies. The present increasing interest of permanent space `bases' located in `deep' space requires that this activity continue toward the goal of protecting from Galactic Cosmic Ray (GCR) a large volume `habitat', allowing long duration permanence in space to citizens conducting there `normal' activities besides to a restricted number of astronauts. The problem had to be stated at this global scale because it must be afforded as soon as possible for preparing the needed technologies and their integration in the spacecraft designs for the future manned exploration and for inhabitation of deep space. The realization of the magnetic protection of large volume habitats by well-established nowadays materials and techniques is in principle possible, but not workable in practice for the huge required mass of the superconductor, the too low operating temperature (10K) and the corresponding required cooling power and thermal shielding. The concept of Cryogen Free Superconducting Magnets is the only one practicable. Fast progress in the production of reliable High Temperature Superconducting (HTS) or MgB2 cables and of cryocoolers suitable for space operation opens the perspective of practicable solutions. Quantitative evaluations for the protection of large volume habitats in deep space from GCRs are reported and discussed.

On the verge of an astronomy CubeSat revolution

NASA Astrophysics Data System (ADS)

Shkolnik, Evgenya L.

2018-05-01

CubeSats are small satellites built in standard sizes and form factors, which have been growing in popularity but have thus far been largely ignored within the field of astronomy. When deployed as space-based telescopes, they enable science experiments not possible with existing or planned large space missions, filling several key gaps in astronomical research. Unlike expensive and highly sought after space telescopes such as the Hubble Space Telescope, whose time must be shared among many instruments and science programs, CubeSats can monitor sources for weeks or months at time, and at wavelengths not accessible from the ground such as the ultraviolet, far-infrared and low-frequency radio. Science cases for CubeSats being developed now include a wide variety of astrophysical experiments, including exoplanets, stars, black holes and radio transients. Achieving high-impact astronomical research with CubeSats is becoming increasingly feasible with advances in technologies such as precision pointing, compact sensitive detectors and the miniaturization of propulsion systems. CubeSats may also pair with the large space- and ground-based telescopes to provide complementary data to better explain the physical processes observed.

Analysis of the effect of attachment point bias during large space debris removal using a tethered space tug

NASA Astrophysics Data System (ADS)

Chu, Zhongyi; Di, Jingnan; Cui, Jing

2017-10-01

Space debris occupies a valuable orbital resource and is an inevitable and urgent problem, especially for large space debris because of its high risk and the possible crippling effects of a collision. Space debris has attracted much attention in recent years. A tethered system used in an active debris removal scenario is a promising method to de-orbit large debris in a safe manner. In a tethered system, the flexibility of the tether used in debris removal can possibly induce tangling, which is dangerous and should be avoided. In particular, attachment point bias due to capture error can significantly affect the motion of debris relative to the tether and increase the tangling risk. Hence, in this paper, the effect of attachment point bias on the tethered system is studied based on a dynamic model established based on a Newtonian approach. Next, a safety metric of avoiding a tangle when a tether is tensioned with attachment point bias is designed to analyse the tangling risk of the tethered system. Finally, several numerical cases are established and simulated to validate the effects of attachment point bias on a space tethered system.

Novel cross-linked polystyrenes with large space network as tailor-made catalyst supports for sustainable media

DOE PAGES

Marrocchi, Assunta; Adriaensens, Peter; Bartollini, Elena; ...

2015-10-09

For a novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,4-bis (4-vinylphenoxy)benzene cross-linker, is introduced; SP-immobilized 1,5,7-triazabicyclo [4.4.0]dec-5-ene (TBD) and triethylamine (TEA) bases are synthesized and characterized in terms of their structural, thermal and morphological features, and their catalytic efficiency in a series of fundamental chemical transformations under solvent-free conditions is investigated.

Laser Remediation of Threats Posed by Small Orbital Debris

NASA Technical Reports Server (NTRS)

Fork, Richard L.; Rogers, Jan R.; Hovater, Mary A.

2012-01-01

The continually increasing amount of orbital debris in near Earth space poses an increasing challenge to space situational awareness. Recent collisions of spacecraft caused abrupt increases in the density of both large and small debris in near Earth space. An especially challenging class of threats is that due to the increasing density of small (1 mm to 10 cm dimension) orbital debris. This small debris poses a serious threat since: (1) The high velocity enables even millimeter dimension debris to cause serious damage to vulnerable areas of space assets, e.g., detector windows; (2) The small size and large number of debris elements prevent adequate detection and cataloguing. We have identified solutions to this threat in the form of novel laser systems and novel ways of using these laser systems. While implementation of the solutions we identify is challenging we find approaches offering threat mitigation within time frames and at costs of practical interest. We base our analysis on the unique combination of coherent light specifically structured in both space and time and applied in novel ways entirely within the vacuum of space to deorbiting small debris. We compare and contrast laser based small debris removal strategies using ground based laser systems with strategies using space based laser systems. We find laser systems located and used entirely within space offer essential and decisive advantages over groundbased laser systems.

RF Systems in Space. Volume I. Space Antennas Frequency (SARF) Simulation.

DTIC Science & Technology

1983-04-01

lens SBR designs were investigated. The survivability of an SBR system was analyzed. The design of ground based SBR validation experiments for large...aperture SBR concepts were investigated. SBR designs were investigated for ground target detection. N1’IS GRAMI DTIC TAB E Unannounced E Justificat... designs :~~.~...: .-..:. ->.. - . *.* . ..- . . .. . -. . ..- . .4. To analyze the survivability of space radar 5. To design ground-based validation

Large Deployable Reflector (LDR) system concept and technology definition study. Analysis of space station requirements for LDR

NASA Astrophysics Data System (ADS)

Agnew, Donald L.; Vinkey, Victor F.; Runge, Fritz C.

1989-04-01

A study was conducted to determine how the Large Deployable Reflector (LDR) might benefit from the use of the space station for assembly, checkout, deployment, servicing, refurbishment, and technology development. Requirements that must be met by the space station to supply benefits for a selected scenario are summarized. Quantitative and qualitative data are supplied. Space station requirements for LDR which may be utilized by other missions are identified. A technology development mission for LDR is outlined and requirements summarized. A preliminary experiment plan is included. Space Station Data Base SAA 0020 and TDM 2411 are updated.

Large Deployable Reflector (LDR) system concept and technology definition study. Analysis of space station requirements for LDR

NASA Technical Reports Server (NTRS)

Agnew, Donald L.; Vinkey, Victor F.; Runge, Fritz C.

1989-01-01

A study was conducted to determine how the Large Deployable Reflector (LDR) might benefit from the use of the space station for assembly, checkout, deployment, servicing, refurbishment, and technology development. Requirements that must be met by the space station to supply benefits for a selected scenario are summarized. Quantitative and qualitative data are supplied. Space station requirements for LDR which may be utilized by other missions are identified. A technology development mission for LDR is outlined and requirements summarized. A preliminary experiment plan is included. Space Station Data Base SAA 0020 and TDM 2411 are updated.

Environmentally-induced voltage limitations in large space power systems

NASA Technical Reports Server (NTRS)

Stevens, N. J.

1984-01-01

Large power systems proposed for future space missions imply higher operating voltage requirements which, in turn, will interact with the space plasma environment. The effects of these interactions can only be inferred because of the limited data base of ground simulations, small test samples, and two space flight experiments. This report evaluates floating potentials for a 100 kW power system operating at 300, 500, 750, and 1000 volts in relation to this data base. Of primary concern is the possibility of discharging to space. The implications of such discharges were studied at the 500 volt operational setting. It was found that discharging can shut down the power system if the discharge current exceeds the array short circuit current. Otherwise, a power oscillation can result that ranges from 2 to 20 percent, depending upon the solar array area involved in the discharge. Means of reducing the effect are discussed.

Computational methods and software systems for dynamics and control of large space structures

NASA Technical Reports Server (NTRS)

Park, K. C.; Felippa, C. A.; Farhat, C.; Pramono, E.

1990-01-01

This final report on computational methods and software systems for dynamics and control of large space structures covers progress to date, projected developments in the final months of the grant, and conclusions. Pertinent reports and papers that have not appeared in scientific journals (or have not yet appeared in final form) are enclosed. The grant has supported research in two key areas of crucial importance to the computer-based simulation of large space structure. The first area involves multibody dynamics (MBD) of flexible space structures, with applications directed to deployment, construction, and maneuvering. The second area deals with advanced software systems, with emphasis on parallel processing. The latest research thrust in the second area, as reported here, involves massively parallel computers.

Habitat Size Optimization of the O'Neill - Glaser Economic Model for Space Solar Satellite Production

NASA Technical Reports Server (NTRS)

Curreri, Peter A.; Detweiler, Michael

2010-01-01

Creating large space habitats by launching all materials from Earth is prohibitively expensive. Using space resources and space based labor to build space solar power satellites can yield extraordinary profits after a few decades. The economic viability of this program depends on the use of space resources and space labor. To maximize the return on the investment, the early use of high density bolo habitats is required. Other shapes do not allow for the small initial scale required for a quick population increase in space. This study found that 5 Man Year, or 384 person bolo high density habitats will be the most economically feasible for a program started at year 2010 and will cause a profit by year 24 of the program, put over 45,000 people into space, and create a large system of space infrastructure for the further exploration and development of space.

Heating of large format filters in sub-mm and fir space optics

NASA Astrophysics Data System (ADS)

Baccichet, N.; Savini, G.

2017-11-01

Most FIR and sub-mm space borne observatories use polymer-based quasi-optical elements like filters and lenses, due to their high transparency and low absorption in such wavelength ranges. Nevertheless, data from those missions have proven that thermal imbalances in the instrument (not caused by filters) can complicate the data analysis. Consequently, for future, higher precision instrumentation, further investigation is required on any thermal imbalances embedded in such polymer-based filters. Particularly, in this paper the heating of polymers when operating at cryogenic temperature in space will be studied. Such phenomenon is an important aspect of their functioning since the transient emission of unwanted thermal radiation may affect the scientific measurements. To assess this effect, a computer model was developed for polypropylene based filters and PTFE-based coatings. Specifically, a theoretical model of their thermal properties was created and used into a multi-physics simulation that accounts for conductive and radiative heating effects of large optical elements, the geometry of which was suggested by the large format array instruments designed for future space missions. It was found that in the simulated conditions, the filters temperature was characterized by a time-dependent behaviour, modulated by a small scale fluctuation. Moreover, it was noticed that thermalization was reached only when a low power input was present.

Modelling the large-scale redshift-space 3-point correlation function of galaxies

NASA Astrophysics Data System (ADS)

Slepian, Zachary; Eisenstein, Daniel J.

2017-08-01

We present a configuration-space model of the large-scale galaxy 3-point correlation function (3PCF) based on leading-order perturbation theory and including redshift-space distortions (RSD). This model should be useful in extracting distance-scale information from the 3PCF via the baryon acoustic oscillation method. We include the first redshift-space treatment of biasing by the baryon-dark matter relative velocity. Overall, on large scales the effect of RSD is primarily a renormalization of the 3PCF that is roughly independent of both physical scale and triangle opening angle; for our adopted Ωm and bias values, the rescaling is a factor of ˜1.8. We also present an efficient scheme for computing 3PCF predictions from our model, important for allowing fast exploration of the space of cosmological parameters in future analyses.

Center for Space Construction Third Annual Symposium

NASA Technical Reports Server (NTRS)

1991-01-01

Viewgraphs from presentations given at the symposium are presented. The topics covered include the following: orbital assembly, large space structures, space stations, expert systems, lunar regolith and structure mechanics, lunar shelter construction from lunar resources, telerobotic rovers, lunar construction equipment, lunar based equipment, and lunar construction.

Large-aperture space optical system testing based on the scanning Hartmann.

PubMed

Wei, Haisong; Yan, Feng; Chen, Xindong; Zhang, Hao; Cheng, Qiang; Xue, Donglin; Zeng, Xuefeng; Zhang, Xuejun

2017-03-10

Based on the Hartmann testing principle, this paper proposes a novel image quality testing technology which applies to a large-aperture space optical system. Compared with the traditional testing method through a large-aperture collimator, the scanning Hartmann testing technology has great advantages due to its simple structure, low cost, and ability to perform wavefront measurement of an optical system. The basic testing principle of the scanning Hartmann testing technology, data processing method, and simulation process are presented in this paper. Certain simulation results are also given to verify the feasibility of this technology. Furthermore, a measuring system is developed to conduct a wavefront measurement experiment for a 200 mm aperture optical system. The small deviation (6.3%) of root mean square (RMS) between experimental results and interferometric results indicates that the testing system can measure low-order aberration correctly, which means that the scanning Hartmann testing technology has the ability to test the imaging quality of a large-aperture space optical system.

Space construction base control system

NASA Technical Reports Server (NTRS)

1978-01-01

Aspects of an attitude control system were studied and developed for a large space base that is structurally flexible and whose mass properties change rather dramatically during its orbital lifetime. Topics of discussion include the following: (1) space base orbital pointing and maneuvering; (2) angular momentum sizing of actuators; (3) momentum desaturation selection and sizing; (4) multilevel control technique applied to configuration one; (5) one-dimensional model simulation; (6) N-body discrete coordinate simulation; (7) structural analysis math model formulation; and (8) discussion of control problems and control methods.

A Hierarchical Framework for State-Space Matrix Inference and Clustering.

PubMed

Zuo, Chandler; Chen, Kailei; Hewitt, Kyle J; Bresnick, Emery H; Keleş, Sündüz

2016-09-01

In recent years, a large number of genomic and epigenomic studies have been focusing on the integrative analysis of multiple experimental datasets measured over a large number of observational units. The objectives of such studies include not only inferring a hidden state of activity for each unit over individual experiments, but also detecting highly associated clusters of units based on their inferred states. Although there are a number of methods tailored for specific datasets, there is currently no state-of-the-art modeling framework for this general class of problems. In this paper, we develop the MBASIC ( M atrix B ased A nalysis for S tate-space I nference and C lustering) framework. MBASIC consists of two parts: state-space mapping and state-space clustering. In state-space mapping, it maps observations onto a finite state-space, representing the activation states of units across conditions. In state-space clustering, MBASIC incorporates a finite mixture model to cluster the units based on their inferred state-space profiles across all conditions. Both the state-space mapping and clustering can be simultaneously estimated through an Expectation-Maximization algorithm. MBASIC flexibly adapts to a large number of parametric distributions for the observed data, as well as the heterogeneity in replicate experiments. It allows for imposing structural assumptions on each cluster, and enables model selection using information criterion. In our data-driven simulation studies, MBASIC showed significant accuracy in recovering both the underlying state-space variables and clustering structures. We applied MBASIC to two genome research problems using large numbers of datasets from the ENCODE project. The first application grouped genes based on transcription factor occupancy profiles of their promoter regions in two different cell types. The second application focused on identifying groups of loci that are similar to a GATA2 binding site that is functional at its endogenous locus by utilizing transcription factor occupancy data and illustrated applicability of MBASIC in a wide variety of problems. In both studies, MBASIC showed higher levels of raw data fidelity than analyzing these data with a two-step approach using ENCODE results on transcription factor occupancy data.

Exploration of a Capability-Focused Aerospace System of Systems Architecture Alternative with Bilayer Design Space, Based on RST-SOM Algorithmic Methods

PubMed Central

Li, Zhifei; Qin, Dongliang

2014-01-01

In defense related programs, the use of capability-based analysis, design, and acquisition has been significant. In order to confront one of the most challenging features of a huge design space in capability based analysis (CBA), a literature review of design space exploration was first examined. Then, in the process of an aerospace system of systems design space exploration, a bilayer mapping method was put forward, based on the existing experimental and operating data. Finally, the feasibility of the foregoing approach was demonstrated with an illustrative example. With the data mining RST (rough sets theory) and SOM (self-organized mapping) techniques, the alternative to the aerospace system of systems architecture was mapping from P-space (performance space) to C-space (configuration space), and then from C-space to D-space (design space), respectively. Ultimately, the performance space was mapped to the design space, which completed the exploration and preliminary reduction of the entire design space. This method provides a computational analysis and implementation scheme for large-scale simulation. PMID:24790572

Exploration of a capability-focused aerospace system of systems architecture alternative with bilayer design space, based on RST-SOM algorithmic methods.

PubMed

Li, Zhifei; Qin, Dongliang; Yang, Feng

2014-01-01

In defense related programs, the use of capability-based analysis, design, and acquisition has been significant. In order to confront one of the most challenging features of a huge design space in capability based analysis (CBA), a literature review of design space exploration was first examined. Then, in the process of an aerospace system of systems design space exploration, a bilayer mapping method was put forward, based on the existing experimental and operating data. Finally, the feasibility of the foregoing approach was demonstrated with an illustrative example. With the data mining RST (rough sets theory) and SOM (self-organized mapping) techniques, the alternative to the aerospace system of systems architecture was mapping from P-space (performance space) to C-space (configuration space), and then from C-space to D-space (design space), respectively. Ultimately, the performance space was mapped to the design space, which completed the exploration and preliminary reduction of the entire design space. This method provides a computational analysis and implementation scheme for large-scale simulation.

Large space telescope, phase A. Volume 3: Optical telescope assembly

NASA Technical Reports Server (NTRS)

1972-01-01

The development and characteristics of the optical telescope assembly for the Large Space Telescope are discussed. The systems considerations are based on mission-related parameters and optical equipment requirements. Information is included on: (1) structural design and analysis, (2) thermal design, (3) stabilization and control, (4) alignment, focus, and figure control, (5) electronic subsystem, and (6) scientific instrument design.

Design of a mission network system using SpaceWire for scientific payloads onboard the Arase spacecraft

NASA Astrophysics Data System (ADS)

Takashima, Takeshi; Ogawa, Emiko; Asamura, Kazushi; Hikishima, Mitsuru

2018-05-01

Arase is a small scientific satellite program conducted by the Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency, which is dedicated to the detailed study of the radiation belts around Earth through in situ observations. In particular, the goal is to directly observe the interaction between plasma waves and particles, which cause the generation of high-energy electrons. To observe the waves and particles in detail, we must record large volumes of burst data with high transmission rates through onboard mission network systems. For this purpose, we developed a high-speed and highly reliable mission network based on SpaceWire, as well as a new and large memory data recorder equipped with a data search function based on observation time (the time index, TI, is the satellite time starting from when the spacecraft is powered on.) with respect to the orbital data generated in large quantities. By adopting a new transaction concept of a ring topology network with SpaceWire, we could secure a redundant mission network system without using large routers and having to suppress the increase in cable weight. We confirmed that their orbit performs as designed.[Figure not available: see fulltext.

Evaluation of Genetic Algorithm Concepts using Model Problems. Part 1; Single-Objective Optimization

NASA Technical Reports Server (NTRS)

Holst, Terry L.; Pulliam, Thomas H.

2003-01-01

A genetic-algorithm-based optimization approach is described and evaluated using a simple hill-climbing model problem. The model problem utilized herein allows for the broad specification of a large number of search spaces including spaces with an arbitrary number of genes or decision variables and an arbitrary number hills or modes. In the present study, only single objective problems are considered. Results indicate that the genetic algorithm optimization approach is flexible in application and extremely reliable, providing optimal results for all problems attempted. The most difficult problems - those with large hyper-volumes and multi-mode search spaces containing a large number of genes - require a large number of function evaluations for GA convergence, but they always converge.

Reinventing the Solar Power Satellite

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2002-01-01

Economy of scale is inherent in the microwave power transmission aperture/spot-size trade-off, resulting in a requirement for large space systems in the existing design concepts. Unfortunately, this large size means that the initial investment required before the first return, and the price of amortization of this initial investment, is a daunting (and perhaps insurmountable) barrier to economic viability. As the growth of ground-based solar power applications will fund the development of the PV technology required for space solar power and will also create the demand for space solar power by manufacturing a ready-made market, space power systems must be designed with an understanding that ground-based solar technologies will be implemented as a precursor to space-based solar. for low initial cost, (3) operation in synergy with ground solar systems, and (4) power production profile tailored to peak rates. A key to simplicity of design is to maximize the integration of the system components. Microwave, millimeter-wave, and laser systems are analyzed. A new solar power satellite design concept with no sun-tracking and no moving parts is proposed to reduce the required cost to initial operational capability.

Impact of large-scale tides on cosmological distortions via redshift-space power spectrum

NASA Astrophysics Data System (ADS)

Akitsu, Kazuyuki; Takada, Masahiro

2018-03-01

Although large-scale perturbations beyond a finite-volume survey region are not direct observables, these affect measurements of clustering statistics of small-scale (subsurvey) perturbations in large-scale structure, compared with the ensemble average, via the mode-coupling effect. In this paper we show that a large-scale tide induced by scalar perturbations causes apparent anisotropic distortions in the redshift-space power spectrum of galaxies in a way depending on an alignment between the tide, wave vector of small-scale modes and line-of-sight direction. Using the perturbation theory of structure formation, we derive a response function of the redshift-space power spectrum to large-scale tide. We then investigate the impact of large-scale tide on estimation of cosmological distances and the redshift-space distortion parameter via the measured redshift-space power spectrum for a hypothetical large-volume survey, based on the Fisher matrix formalism. To do this, we treat the large-scale tide as a signal, rather than an additional source of the statistical errors, and show that a degradation in the parameter is restored if we can employ the prior on the rms amplitude expected for the standard cold dark matter (CDM) model. We also discuss whether the large-scale tide can be constrained at an accuracy better than the CDM prediction, if the effects up to a larger wave number in the nonlinear regime can be included.

Science Discoveries Enabled by Hosting Optical Imagers on Commercial Satellite Constellations

NASA Astrophysics Data System (ADS)

Erlandson, R. E.; Kelly, M. A.; Hibbitts, C.; Kumar, C.; Dyrud, L. P.

2012-12-01

The advent of commercial space activities that utilize large space-based constellations provide a new and cost effective opportunity to acquire multi-point observations. Previously, a custom designed space-based constellation, while technically feasible, would require a substantial monetary investment. However, commercial industry has now been entertaining the concept of hosting payloads on their space-based constellations resulting in low-cost access to space. Examples, include the low Earth orbit Iridium Next constellation as well as communication satellites in geostationary. In some of these constellations data distribution can be provided in real time, a feature relevant to applications in the areas of space weather and disaster monitoring. From the perspective of new scientific discoveries enabled by low cost access to space, the cost and thus value proposition is dramatically changed. For example, a constellation of sixty-six satellites (Iridium Next), hosting a single band or multi-spectral imager can now provide observations of the aurora with a spatial resolution of a few hundred meters at all local times and in both hemispheres simultaneously. Remote sensing of clouds is another example where it is now possible to acquire global imagery at resolutions between 100-1000m. Finally, land use imagery is another example where one can use either imaging or spectrographic imagers to solve a multitude of problems. In this work, we will discuss measurement architectures and the multi-disciplinary scientific discoveries that are enable by large space based constellations.

HSTDEK: Developing a methodology for construction of large-scale, multi-use knowledge bases

NASA Technical Reports Server (NTRS)

Freeman, Michael S.

1987-01-01

The primary research objectives of the Hubble Space Telescope Design/Engineering Knowledgebase (HSTDEK) are to develop a methodology for constructing and maintaining large scale knowledge bases which can be used to support multiple applications. To insure the validity of its results, this research is being persued in the context of a real world system, the Hubble Space Telescope. The HSTDEK objectives are described in detail. The history and motivation of the project are briefly described. The technical challenges faced by the project are outlined.

Deep space communication - A one billion mile noisy channel

NASA Technical Reports Server (NTRS)

Smith, J. G.

1982-01-01

Deep space exploration is concerned with the study of natural phenomena in the solar system with the aid of measurements made at spacecraft on deep space missions. Deep space communication refers to communication between earth and spacecraft in deep space. The Deep Space Network is an earth-based facility employed for deep space communication. It includes a network of large tracking antennas located at various positions around the earth. The goals and achievements of deep space exploration over the past 20 years are discussed along with the broad functional requirements of deep space missions. Attention is given to the differences in space loss between communication satellites and deep space vehicles, effects of the long round-trip light time on spacecraft autonomy, requirements for the use of massive nuclear power plants on spacecraft at large distances from the sun, and the kinds of scientific return provided by a deep space mission. Problems concerning a deep space link of one billion miles are also explored.

LDR system concepts and technology

NASA Technical Reports Server (NTRS)

Pittman, B.

1985-01-01

The Large Deployable Reflector is a 20 meter diameter infrared/submillimeter telescope planned for the late 1990's. The Astronomy Survey Committee of the National Academy of Sciences (Field Committee) recommended LDR as one of the two space based observatories that should start development in the 80's. LDR's large aperture will give it unequaled resolution in the wavelength range from 30 to 1000 microns. To meet LDR performance goals will call for advances in several technology disciplines including: optics, controls, thermal control, detectors, cryogenic cooling, and large space structures.

Fifty years of human space travel: implications for bone and calcium research

USDA-ARS?s Scientific Manuscript database

Calcium and bone metabolism remain key concerns for space travelers, and ground-based models of space flight have provided a vast literature to complement the smaller set of reports from flight studies. Increased bone resorption and largely unchanged bone formation result in the loss of calcium and ...

Nature-based strategies for improving urban health and safety

Treesearch

Michelle C. Kondo; Eugenia C. South; Charles C. Branas

2015-01-01

Place-based programs are being noticed as key opportunities to prevent disease and promote public health and safety for populations at-large. As one key type of place-based intervention, nature-based and green space strategies can play an especially large role in improving health and safety for dwellers in urban environments such as US legacy cities that lack nature...

Space station accommodations for lunar base elements: A study

NASA Technical Reports Server (NTRS)

Weidman, Deene J.; Cirillo, William; Llewellyn, Charles; Kaszubowski, Martin; Kienlen, E. Michael, Jr.

1987-01-01

The results of a study conducted at NASA-LaRC to assess the impact on the space station of accommodating a Manned Lunar Base are documented. Included in the study are assembly activities for all infrastructure components, resupply and operations support for lunar base elements, crew activity requirements, the effect of lunar activities on Cape Kennedy operations, and the effect on space station science missions. Technology needs to prepare for such missions are also defined. Results of the study indicate that the space station can support the manned lunar base missions with the addition of a Fuel Depot Facility and a heavy lift launch vehicle to support the large launch requirements.

An optimal beam alignment method for large-scale distributed space surveillance radar system

NASA Astrophysics Data System (ADS)

Huang, Jian; Wang, Dongya; Xia, Shuangzhi

2018-06-01

Large-scale distributed space surveillance radar is a very important ground-based equipment to maintain a complete catalogue for Low Earth Orbit (LEO) space debris. However, due to the thousands of kilometers distance between each sites of the distributed radar system, how to optimally implement the Transmitting/Receiving (T/R) beams alignment in a great space using the narrow beam, which proposed a special and considerable technical challenge in the space surveillance area. According to the common coordinate transformation model and the radar beam space model, we presented a two dimensional projection algorithm for T/R beam using the direction angles, which could visually describe and assess the beam alignment performance. Subsequently, the optimal mathematical models for the orientation angle of the antenna array, the site location and the T/R beam coverage are constructed, and also the beam alignment parameters are precisely solved. At last, we conducted the optimal beam alignment experiments base on the site parameters of Air Force Space Surveillance System (AFSSS). The simulation results demonstrate the correctness and effectiveness of our novel method, which can significantly stimulate the construction for the LEO space debris surveillance equipment.

Large scale cryogenic fluid systems testing

NASA Technical Reports Server (NTRS)

1992-01-01

NASA Lewis Research Center's Cryogenic Fluid Systems Branch (CFSB) within the Space Propulsion Technology Division (SPTD) has the ultimate goal of enabling the long term storage and in-space fueling/resupply operations for spacecraft and reusable vehicles in support of space exploration. Using analytical modeling, ground based testing, and on-orbit experimentation, the CFSB is studying three primary categories of fluid technology: storage, supply, and transfer. The CFSB is also investigating fluid handling, advanced instrumentation, and tank structures and materials. Ground based testing of large-scale systems is done using liquid hydrogen as a test fluid at the Cryogenic Propellant Tank Facility (K-site) at Lewis' Plum Brook Station in Sandusky, Ohio. A general overview of tests involving liquid transfer, thermal control, pressure control, and pressurization is given.

DOD Space Systems: Additional Knowledge Would Better Support Decisions about Disaggregating Large Satellites

DTIC Science & Technology

2014-10-01

considering new approaches. According to Air Force Space Command, U.S. space systems face intentional and unintentional threats , which have increased...life cycle costs • Demand for more satellites may stimulate new entrants and competition to lower acquisition costs. • Smaller, less complex...Fiscal constraints and growing threats to space systems have led DOD to consider alternatives for acquiring space-based capabilities, including

Novel method to construct large-scale design space in lubrication process utilizing Bayesian estimation based on a small-scale design-of-experiment and small sets of large-scale manufacturing data.

PubMed

Maeda, Jin; Suzuki, Tatsuya; Takayama, Kozo

2012-12-01

A large-scale design space was constructed using a Bayesian estimation method with a small-scale design of experiments (DoE) and small sets of large-scale manufacturing data without enforcing a large-scale DoE. The small-scale DoE was conducted using various Froude numbers (X(1)) and blending times (X(2)) in the lubricant blending process for theophylline tablets. The response surfaces, design space, and their reliability of the compression rate of the powder mixture (Y(1)), tablet hardness (Y(2)), and dissolution rate (Y(3)) on a small scale were calculated using multivariate spline interpolation, a bootstrap resampling technique, and self-organizing map clustering. The constant Froude number was applied as a scale-up rule. Three experiments under an optimal condition and two experiments under other conditions were performed on a large scale. The response surfaces on the small scale were corrected to those on a large scale by Bayesian estimation using the large-scale results. Large-scale experiments under three additional sets of conditions showed that the corrected design space was more reliable than that on the small scale, even if there was some discrepancy in the pharmaceutical quality between the manufacturing scales. This approach is useful for setting up a design space in pharmaceutical development when a DoE cannot be performed at a commercial large manufacturing scale.

Bundles over nearly-Kahler homogeneous spaces in heterotic string theory

NASA Astrophysics Data System (ADS)

Klaput, Michael; Lukas, Andre; Matti, Cyril

2011-09-01

We construct heterotic vacua based on six-dimensional nearly-Kahler homogeneous manifolds and non-trivial vector bundles thereon. Our examples are based on three specific group coset spaces. It is shown how to construct line bundles over these spaces, compute their properties and build up vector bundles consistent with supersymmetry and anomaly cancelation. It turns out that the most interesting coset is SU(3)/U(1)2. This space supports a large number of vector bundles which lead to consistent heterotic vacua, some of them with three chiral families.

Learning SVM in Kreĭn Spaces.

PubMed

Loosli, Gaelle; Canu, Stephane; Ong, Cheng Soon

2016-06-01

This paper presents a theoretical foundation for an SVM solver in Kreĭn spaces. Up to now, all methods are based either on the matrix correction, or on non-convex minimization, or on feature-space embedding. Here we justify and evaluate a solution that uses the original (indefinite) similarity measure, in the original Kreĭn space. This solution is the result of a stabilization procedure. We establish the correspondence between the stabilization problem (which has to be solved) and a classical SVM based on minimization (which is easy to solve). We provide simple equations to go from one to the other (in both directions). This link between stabilization and minimization problems is the key to obtain a solution in the original Kreĭn space. Using KSVM, one can solve SVM with usually troublesome kernels (large negative eigenvalues or large numbers of negative eigenvalues). We show experiments showing that our algorithm KSVM outperforms all previously proposed approaches to deal with indefinite matrices in SVM-like kernel methods.

Sensitivity study of Space Station Freedom operations cost and selected user resources

NASA Technical Reports Server (NTRS)

Accola, Anne; Fincannon, H. J.; Williams, Gregory J.; Meier, R. Timothy

1990-01-01

The results of sensitivity studies performed to estimate probable ranges for four key Space Station parameters using the Space Station Freedom's Model for Estimating Space Station Operations Cost (MESSOC) are discussed. The variables examined are grouped into five main categories: logistics, crew, design, space transportation system, and training. The modification of these variables implies programmatic decisions in areas such as orbital replacement unit (ORU) design, investment in repair capabilities, and crew operations policies. The model utilizes a wide range of algorithms and an extensive trial logistics data base to represent Space Station operations. The trial logistics data base consists largely of a collection of the ORUs that comprise the mature station, and their characteristics based on current engineering understanding of the Space Station. A nondimensional approach is used to examine the relative importance of variables on parameters.

Large antenna measurement and compensation techniques

NASA Technical Reports Server (NTRS)

Rahmatsamii, Y.

1989-01-01

Antennas in the range of 20 meters or larger will be an integral part of future satellite communication and scientific payloads. In order to commercially use these large, low sidelobe and multiple-beam antennas, a high level of confidence must be established as to their performance in the 0-g and space environment. It is also desirable to compensate for slowly varying surface distortions which could results from thermal effects. An overview of recent advances in performing rf measurements on large antennas is presented with emphasis given to the application of a space-based far-field range utilizing the Space Shuttle. The concept of surface distortion compensation is discussed by providing numerical and measurement results.

A general-purpose development environment for intelligent computer-aided training systems

NASA Technical Reports Server (NTRS)

Savely, Robert T.

1990-01-01

Space station training will be a major task, requiring the creation of large numbers of simulation-based training systems for crew, flight controllers, and ground-based support personnel. Given the long duration of space station missions and the large number of activities supported by the space station, the extension of space shuttle training methods to space station training may prove to be impractical. The application of artificial intelligence technology to simulation training can provide the ability to deliver individualized training to large numbers of personnel in a distributed workstation environment. The principal objective of this project is the creation of a software development environment which can be used to build intelligent training systems for procedural tasks associated with the operation of the space station. Current NASA Johnson Space Center projects and joint projects with other NASA operational centers will result in specific training systems for existing space shuttle crew, ground support personnel, and flight controller tasks. Concurrently with the creation of these systems, a general-purpose development environment for intelligent computer-aided training systems will be built. Such an environment would permit the rapid production, delivery, and evolution of training systems for space station crew, flight controllers, and other support personnel. The widespread use of such systems will serve to preserve task and training expertise, support the training of many personnel in a distributed manner, and ensure the uniformity and verifiability of training experiences. As a result, significant reductions in training costs can be realized while safety and the probability of mission success can be enhanced.

14 CFR 135.387 - Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate airports.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine....387 Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate... alternate airport for a turbine engine powered large transport category airplane unless (based on the...

14 CFR 135.387 - Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate airports.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine....387 Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate... alternate airport for a turbine engine powered large transport category airplane unless (based on the...

14 CFR 135.387 - Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate airports.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine....387 Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate... alternate airport for a turbine engine powered large transport category airplane unless (based on the...

Attitude control/momentum management of the Space Station Freedom for large angle torque-equilibrium-attitude configurations

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Sunkel, John W.

1990-01-01

An attitude-control and momentum-management (ACMM) system for the Space Station in a large-angle torque-equilibrium-attitude (TEA) configuration is developed analytically and demonstrated by means of numerical simulations. The equations of motion for a rigid-body Space Station model are outlined; linearized equations for an arbitrary TEA (resulting from misalignment of control and body axes) are derived; the general requirements for an ACMM are summarized; and a pole-placement linear-quadratic regulator solution based on scheduled gains is proposed. Results are presented in graphs for (1) simulations based on configuration MB3 (showing the importance of accounting for the cross-inertia terms in the TEA estimate) and (2) simulations of a stepwise change from configuration MB3 to the 'assembly complete' stage over 130 orbits (indicating that the present ACCM scheme maintains sufficient control over slowly varying Space Station dynamics).

Back-illuminated large area frame transfer CCDs for space-based hyper-spectral imaging applications

NASA Astrophysics Data System (ADS)

Philbrick, Robert H.; Gilmore, Angelo S.; Schrein, Ronald J.

2016-07-01

Standard offerings of large area, back-illuminated full frame CCD sensors are available from multiple suppliers and they continue to be commonly deployed in ground- and space-based applications. By comparison the availability of large area frame transfers CCDs is sparse, with the accompanying 2x increase in die area no doubt being a contributing factor. Modern back-illuminated CCDs yield very high quantum efficiency in the 290 to 400 nm band, a wavelength region of great interest in space-based instruments studying atmospheric phenomenon. In fast framing (e.g. 10 - 20 Hz), space-based applications such as hyper-spectral imaging, the use of a mechanical shutter to block incident photons during readout can prove costly and lower instrument reliability. The emergence of large area, all-digital visible CMOS sensors, with integrate while read functionality, are an alternative solution to CCDs; but, even after factoring in reduced complexity and cost of support electronics, the present cost to implement such novel sensors is prohibitive to cost constrained missions. Hence, there continues to be a niche set of applications where large area, back-illuminated frame transfer CCDs with high UV quantum efficiency, high frame rate, high full well, and low noise provide an advantageous solution. To address this need a family of large area frame transfer CCDs has been developed that includes 2048 (columns) x 256 (rows) (FT4), 2048 x 512 (FT5), and 2048 x 1024 (FT6) full frame transfer CCDs; and a 2048 x 1024 (FT7) split-frame transfer CCD. Each wafer contains 4 FT4, 2 FT5, 2 FT6, and 2 FT7 die. The designs have undergone radiation and accelerated life qualification and the electro-optical performance of these CCDs over the wavelength range of 290 to 900 nm is discussed.

High performance large infrared and visible astronomy arrays for low background applications: instruments performance data and future developments at Raytheon

NASA Astrophysics Data System (ADS)

Beuville, Eric; Acton, David; Corrales, Elizabeth; Drab, John; Levy, Alan; Merrill, Michael; Peralta, Richard; Ritchie, William

2007-09-01

Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared detector arrays for astronomy and civil space applications. RVS offers unique off-the-shelf solutions to the astronomy community. This paper describes mega-pixel arrays, based on multiple detector materials, developed for astronomy and low-background applications. New focal plane arrays under development at RVS for the astronomy community will also be presented. Large Sensor Chip Assemblies (SCAs) using various detector materials like Si:PIN, HgCdTe, InSb, and Si:As IBC, covering a detection range from visible to large wavelength infrared (LWIR) have been demonstrated with an excellent quantum efficiency and very good uniformity. These focal plane arrays have been assembled using state-of-the-art low noise, low power, readout integrated circuits (ROIC) designed at RVS. Raytheon packaging capabilities address reliability, precision alignment and flatness requirements for both ground-based and space applications. Multiple SCAs can be packaged into even larger focal planes. The VISTA telescope, for example, contains sixteen 2k × 2k infrared focal plane arrays. RVS astronomical arrays are being deployed world-wide in ground-based and space-based applications. A summary of performance data for each of these array types from instruments in operation will be presented (VIRGO Array for large format SWIR, the ORION and VISTA Arrays, NEWFIRM and other solutions for MWIR spectral ranges).

A lone desert Joshua tree greeted the arrival of Space Shuttle Endeavour at Edwards Air Force Base,

NASA Technical Reports Server (NTRS)

2001-01-01

A lone desert Joshua tree greeted the arrival of Space Shuttle Endeavour at Edwards Air Force Base, California, May 1, 2001. A large drag chute helped slow Endeavour on the runway. After mounting the shuttle on a converted 747 airliner at NASA's Dryden Flight Research Center, Endeavour will be carried back to the Kennedy Space Center for its next mission. Weather in Florida necessitated landing in California.

Large Deployable Reflector (LDR) Requirements for Space Station Accommodations

NASA Technical Reports Server (NTRS)

Crowe, D. A.; Clayton, M. J.; Runge, F. C.

1985-01-01

Top level requirements for assembly and integration of the Large Deployable Reflector (LDR) Observatory at the Space Station are examined. Concepts are currently under study for LDR which will provide a sequel to the Infrared Astronomy Satellite and the Space Infrared Telescope Facility. LDR will provide a spectacular capability over a very broad spectral range. The Space Station will provide an essential facility for the initial assembly and check out of LDR, as well as a necessary base for refurbishment, repair and modification. By providing a manned platform, the Space Station will remove the time constraint on assembly associated with use of the Shuttle alone. Personnel safety during necessary EVA is enhanced by the presence of the manned facility.

Large Deployable Reflector (LDR) requirements for space station accommodations

NASA Astrophysics Data System (ADS)

Crowe, D. A.; Clayton, M. J.; Runge, F. C.

1985-04-01

Top level requirements for assembly and integration of the Large Deployable Reflector (LDR) Observatory at the Space Station are examined. Concepts are currently under study for LDR which will provide a sequel to the Infrared Astronomy Satellite and the Space Infrared Telescope Facility. LDR will provide a spectacular capability over a very broad spectral range. The Space Station will provide an essential facility for the initial assembly and check out of LDR, as well as a necessary base for refurbishment, repair and modification. By providing a manned platform, the Space Station will remove the time constraint on assembly associated with use of the Shuttle alone. Personnel safety during necessary EVA is enhanced by the presence of the manned facility.

Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads

NASA Technical Reports Server (NTRS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Transient and steady-state tests of the space power research engine with resistive and motor loads

NASA Astrophysics Data System (ADS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Towards physics responsible for large-scale Lyman-α forest bias parameters

DOE PAGES

Agnieszka M. Cieplak; Slosar, Anze

2016-03-08

Using a series of carefully constructed numerical experiments based on hydrodynamic cosmological SPH simulations, we attempt to build an intuition for the relevant physics behind the large scale density (b δ) and velocity gradient (b η) biases of the Lyman-α forest. Starting with the fluctuating Gunn-Peterson approximation applied to the smoothed total density field in real-space, and progressing through redshift-space with no thermal broadening, redshift-space with thermal broadening and hydrodynamically simulated baryon fields, we investigate how approximations found in the literature fare. We find that Seljak's 2012 analytical formulae for these bias parameters work surprisingly well in the limit ofmore » no thermal broadening and linear redshift-space distortions. We also show that his b η formula is exact in the limit of no thermal broadening. Since introduction of thermal broadening significantly affects its value, we speculate that a combination of large-scale measurements of b η and the small scale flux PDF might be a sensitive probe of the thermal state of the IGM. Lastly, we find that large-scale biases derived from the smoothed total matter field are within 10–20% to those based on hydrodynamical quantities, in line with other measurements in the literature.« less

Towards physics responsible for large-scale Lyman-α forest bias parameters

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

Agnieszka M. Cieplak; Slosar, Anze

Using a series of carefully constructed numerical experiments based on hydrodynamic cosmological SPH simulations, we attempt to build an intuition for the relevant physics behind the large scale density (b δ) and velocity gradient (b η) biases of the Lyman-α forest. Starting with the fluctuating Gunn-Peterson approximation applied to the smoothed total density field in real-space, and progressing through redshift-space with no thermal broadening, redshift-space with thermal broadening and hydrodynamically simulated baryon fields, we investigate how approximations found in the literature fare. We find that Seljak's 2012 analytical formulae for these bias parameters work surprisingly well in the limit ofmore » no thermal broadening and linear redshift-space distortions. We also show that his b η formula is exact in the limit of no thermal broadening. Since introduction of thermal broadening significantly affects its value, we speculate that a combination of large-scale measurements of b η and the small scale flux PDF might be a sensitive probe of the thermal state of the IGM. Lastly, we find that large-scale biases derived from the smoothed total matter field are within 10–20% to those based on hydrodynamical quantities, in line with other measurements in the literature.« less

Ground-Based and Space-Based Laser Beam Power Applications

NASA Technical Reports Server (NTRS)

Bozek, John M.

1995-01-01

A space power system based on laser beam power is sized to reduce mass, increase operational capabilities, and reduce complexity. The advantages of laser systems over solar-based systems are compared as a function of application. Power produced from the conversion of a laser beam that has been generated on the Earth's surface and beamed into cislunar space resulted in decreased round-trip time for Earth satellite electric propulsion tugs and a substantial landed mass savings for a lunar surface mission. The mass of a space-based laser system (generator in space and receiver near user) that beams down to an extraterrestrial airplane, orbiting spacecraft, surface outpost, or rover is calculated and compared to a solar system. In general, the advantage of low mass for these space-based laser systems is limited to high solar eclipse time missions at distances inside Jupiter. The power system mass is less in a continuously moving Mars rover or surface outpost using space-based laser technology than in a comparable solar-based power system, but only during dust storm conditions. Even at large distances for the Sun, the user-site portion of a space-based laser power system (e.g., the laser receiver component) is substantially less massive than a solar-based system with requisite on-board electrochemical energy storage.

Large-Eddy Simulation of the Base Flow of a Cylindrical Space Vehicle Configuration

NASA Astrophysics Data System (ADS)

Meiß, J.-H.; Schröder, W.

2009-01-01

A Large-Eddy Simulation (LES) is performed out to in- vestigate high Reynolds number base flow of an axisymmetric rocket-like configuration having an underex- panded nozzle flow. The subsonic base region of low pressure levels is characterized and bounded by the interaction of the freestream of Mach 5.3 and the wide plume of the hot exhaust jet of Mach 3.8. An analysis of the base flow shows that the system of base area vortices determines the highly time-dependent pressure distribution and causes an upstream convection of hot exhaust gas. A comparison of the results with experiments conducted at the German Aerospace Center (DLR) Cologne shows good agreement. The investigation is part of the German RESPACE Pro- gram, which focuses on Key Technologies for Reusable Space Systems.

Free-style Deepithelialized Propeller Flaps: An Ideal Local Flap to Obliterate Wounds with Dead Space.

PubMed

Datli, Asli; Suh, HyunSuk; Kim, Young Chul; Choi, Doon Hoon; Hong, Joon Pio Jp

2017-03-01

The reconstruction of the posterior trunk, especially with large dead spaces, remains challenging. Regional muscle flaps may lack adequate volume and reach. The purpose of this report was to evaluate the efficacy of deepithelialized free-style perforator-based propeller flaps to obliterate defects with large dead space. A total of 7 patients with defects on the posterior trunk with large dead spaces were evaluated. After complete debridement or resection, all flaps were designed on a single perforator adjacent to the defect, deepithelialized, and then rotated in a propeller fashion. Flaps were further modified in some cases such as folding the flap after deepithelialization to increase bulk and to obliterate the dead space. The flap dimension ranged from 10 × 5 × 1 to 15 × 8 × 2.5 cm based on a single perforator. The rotation arch of the flap ranged from 90 to 180 degrees. Uneventful healing was noted in all cases. One case showed latent redness and swelling at 7 months after falling down, which resolved with medication. During the average follow-up of 28 months, there were no other flap and donor site complications. The deepithelialized propeller flap can be used efficiently to obliterate dead spaces in the posterior trunk and retains advantages such as having a good vascular supply, adequate bulk, sufficient reach without tension, and minimal donor site morbidity.

Attitude and vibration control of a large flexible space-based antenna

NASA Technical Reports Server (NTRS)

Joshi, S. M.

1982-01-01

Control systems synthesis is considered for controlling the rigid body attitude and elastic motion of a large deployable space-based antenna. Two methods for control systems synthesis are considered. The first method utilizes the stability and robustness properties of the controller consisting of torque actuators and collocated attitude and rate sensors. The second method is based on the linear-quadratic-Gaussian control theory. A combination of the two methods, which results in a two level hierarchical control system, is also briefly discussed. The performance of the controllers is analyzed by computing the variances of pointing errors, feed misalignment errors and surface contour errors in the presence of sensor and actuator noise.

Development of a verification program for deployable truss advanced technology

NASA Technical Reports Server (NTRS)

Dyer, Jack E.

1988-01-01

Use of large deployable space structures to satisfy the growth demands of space systems is contingent upon reducing the associated risks that pervade many related technical disciplines. The overall objectives of this program was to develop a detailed plan to verify deployable truss advanced technology applicable to future large space structures and to develop a preliminary design of a deployable truss reflector/beam structure for use a a technology demonstration test article. The planning is based on a Shuttle flight experiment program using deployable 5 and 15 meter aperture tetrahedral truss reflections and a 20 m long deployable truss beam structure. The plan addresses validation of analytical methods, the degree to which ground testing adequately simulates flight and in-space testing requirements for large precision antenna designs. Based on an assessment of future NASA and DOD space system requirements, the program was developed to verify four critical technology areas: deployment, shape accuracy and control, pointing and alignment, and articulation and maneuvers. The flight experiment technology verification objectives can be met using two shuttle flights with the total experiment integrated on a single Shuttle Test Experiment Platform (STEP) and a Mission Peculiar Experiment Support Structure (MPESS). First flight of the experiment can be achieved 60 months after go-ahead with a total program duration of 90 months.

A lone desert Joshua tree greeted the arrival of Space Shuttle Endeavour at Edwards Air Force Base, California, on May 1, 2001

NASA Image and Video Library

2001-05-01

A lone desert Joshua tree greeted the arrival of Space Shuttle Endeavour at Edwards Air Force Base, California, May 1, 2001. A large drag chute helped slow Endeavour on the runway. After mounting the shuttle on a converted 747 airliner at NASA's Dryden Flight Research Center, Endeavour will be carried back to the Kennedy Space Center for its next mission. Weather in Florida necessitated landing in California.

A soft actuation system for segmented reflector articulation and isolation

NASA Technical Reports Server (NTRS)

Agronin, Michael L.; Jandura, Louise

1990-01-01

Segmented reflectors have been proposed for space based applications such as optical communication and large diameter telescopes. An actuation system for mirrors in a space based segmented mirror array was developed as part of NASA's Precision Segmented Reflector program. The actuation system, called the Articulated Panel Module (APM), provides 3 degrees of freedom mirror articulation, gives isolation from structural motion, and simplifies space assembly of the mirrors to the reflector backup truss. A breadboard of the APM was built and is described.

Space construction base support requirements for environmental control and life support systems

NASA Technical Reports Server (NTRS)

Thiele, R. J.; Secord, T. C.; Murphy, G. L.

1977-01-01

A Space Station analysis study is being performed for NASA which identifies cost-effective Space Station options that can provide a space facility capable of performing space construction, space manufacturing, cosmological research, earth services, and other functions. A space construction base concept for the construction of large structures, such as those needed to implement satellite solar power for earth usage, will be used as a basis for discussing requirements that impact the design selection, level of integration, and operation of environmental control and life support systems (ECLSS). The space construction base configuration also provides a basic Space Station facility that can accommodate biological manufacturing modules, ultrapure glasses manufacturing modules, and modules for other services in a building-block fashion. Examples of special problems that could dictate hardware required to augment the basic ECLSS for autonomous modules will be highlighted. Additionally, overall intravehicular (IVA) and extravehicular (EVA) activities and requirements that could impact the basic station ECLSS degree of closure are discussed.

Control technology development

NASA Astrophysics Data System (ADS)

Schaechter, D. B.

1982-03-01

The main objectives of the control technology development task are given in the slide below. The first is to develop control design techniques based on flexible structural models, rather than simple rigid-body models. Since large space structures are distributed parameter systems, a new degree of freedom, that of sensor/actuator placement, may be exercised for improving control system performance. Another characteristic of large space structures is numerous oscillatory modes within the control bandwidth. Reduced-order controller design models must be developed which produce stable closed-loop systems when combined with the full-order system. Since the date of an actual large-space-structure flight is rapidly approaching, it is vitally important that theoretical developments are tested in actual hardware. Experimental verification is a vital counterpart of all current theoretical developments.

NASA philosophy concerning space stations as operations centers for construction and maintenance of large orbiting energy systems

NASA Technical Reports Server (NTRS)

Freitag, R. F.

1976-01-01

Future United States plans for manned space-flight activities are summarized, emphasizing the long-term goals of achieving permanent occupancy and limited self-sufficiency in space. NASA-sponsored studies of earth-orbiting Space Station concepts are reviewed along with lessons learned from the Skylab missions. Descriptions are presented of the Space Transportation System, the Space Construction Base, and the concept of space industrialization (the processing and manufacturing of goods in space). Future plans for communications satellites, solar-power satellites, terrestrial observations from space stations, and manned orbital-transfer vehicles are discussed.

An overview of expert systems. [artificial intelligence

NASA Technical Reports Server (NTRS)

Gevarter, W. B.

1982-01-01

An expert system is defined and its basic structure is discussed. The knowledge base, the inference engine, and uses of expert systems are discussed. Architecture is considered, including choice of solution direction, reasoning in the presence of uncertainty, searching small and large search spaces, handling large search spaces by transforming them and by developing alternative or additional spaces, and dealing with time. Existing expert systems are reviewed. Tools for building such systems, construction, and knowledge acquisition and learning are discussed. Centers of research and funding sources are listed. The state-of-the-art, current problems, required research, and future trends are summarized.

James Webb Space telescope optical simulation testbed: experimental results with linear control alignment

NASA Astrophysics Data System (ADS)

Egron, Sylvain; Lajoie, Charles-Philippe; Michau, Vincent; Bonnefois, Aurélie; Escolle, Clément; Leboulleux, Lucie; N'Diaye, Mamadou; Pueyo, Laurent; Choquet, Elodie; Perrin, Marshall D.; Ygouf, Marie; Fusco, Thierry; Ferrari, Marc; Hugot, Emmanuel; Soummer, Rémi

2017-09-01

The current generation of terrestrial telescopes has large enough primary mirror diameters that active optical control based on wavefront sensing is necessary. Similarly, in space, while the Hubble Space Telescope (HST) has a mostly passive optical design, apart from focus control, its successor the James Webb Space Telescope (JWST) has active control of many degrees of freedom in its primary and secondary mirrors.

Potential converter for laser-power beaming

NASA Technical Reports Server (NTRS)

Walker, Gilbert H.; Williams, Michael D.; Schuster, Gregory L.; Iles, Peter A.

1991-01-01

Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described.

Research and technology, fiscal year 1982

NASA Technical Reports Server (NTRS)

1982-01-01

Advanced studies are reviewed. Atmospheric sciences, magnetospheric physics, solar physics, gravitational physics, astronomy, and materials processing in space comprise the research programs. Large space systems, propulsion technology, materials and processes, electrical/electronic systems, data bases/design criteria, and facilities development comprise the technology development activities.

Solubility limits in quaternary SnTe-based alloys

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

Siol, Sebastian; Holder, Aaron; Ortiz, Brenden R.

2017-01-01

A combined theoretical and experimental approach was used to determine the equilibrium as well as non-equilibrium solubility lines in the quaternary Sn 1-yMn yTe 1-xSe xalloy space, revealing a large area of accessible metastable phase space.

Exploring representations of protein structure for automated remote homology detection and mapping of protein structure space

PubMed Central

2014-01-01

Background Due to rapid sequencing of genomes, there are now millions of deposited protein sequences with no known function. Fast sequence-based comparisons allow detecting close homologs for a protein of interest to transfer functional information from the homologs to the given protein. Sequence-based comparison cannot detect remote homologs, in which evolution has adjusted the sequence while largely preserving structure. Structure-based comparisons can detect remote homologs but most methods for doing so are too expensive to apply at a large scale over structural databases of proteins. Recently, fragment-based structural representations have been proposed that allow fast detection of remote homologs with reasonable accuracy. These representations have also been used to obtain linearly-reducible maps of protein structure space. It has been shown, as additionally supported from analysis in this paper that such maps preserve functional co-localization of the protein structure space. Methods Inspired by a recent application of the Latent Dirichlet Allocation (LDA) model for conducting structural comparisons of proteins, we propose higher-order LDA-obtained topic-based representations of protein structures to provide an alternative route for remote homology detection and organization of the protein structure space in few dimensions. Various techniques based on natural language processing are proposed and employed to aid the analysis of topics in the protein structure domain. Results We show that a topic-based representation is just as effective as a fragment-based one at automated detection of remote homologs and organization of protein structure space. We conduct a detailed analysis of the information content in the topic-based representation, showing that topics have semantic meaning. The fragment-based and topic-based representations are also shown to allow prediction of superfamily membership. Conclusions This work opens exciting venues in designing novel representations to extract information about protein structures, as well as organizing and mining protein structure space with mature text mining tools. PMID:25080993

MIC-Large Scale Magnetically Inflated Cable Structures for Space Power, Propulsion, Communications and Observational Applications

NASA Astrophysics Data System (ADS)

Powell, James; Maise, George; Rather, John

2010-01-01

A new approach for the erection of rigid large scale structures in space-MIC (Magnetically Inflated Cable)-is described. MIC structures are launched as a compact payload of superconducting cables and attached tethers. After reaching orbit, the superconducting cables are energized with electrical current. The magnet force interactions between the cables cause them to expand outwards into the final large structure. Various structural shapes and applications are described. The MIC structure can be a simple flat disc with a superconducting outer ring that supports a tether network holding a solar cell array, or it can form a curved mirror surface that concentrates light and focuses it on a smaller region-for example, a high flux solar array that generates electric power, a high temperature receiver that heats H2 propellant for high Isp propulsion, and a giant primary reflector for a telescope for astronomy and Earth surveillance. Linear dipole and quadrupole MIC structures are also possible. The linear quadrupole structure can be used for magnetic shielding against cosmic radiation for astronauts, for example. MIC could use lightweight YBCO superconducting HTS (High Temperature Superconductor) cables, that can operate with liquid N2 coolant at engineering current densities of ~105 amp/cm2. A 1 kilometer length of MIC cable would weigh only 3 metric tons, including superconductor, thermal insulations, coolant circuits, and refrigerator, and fit within a 3 cubic meter compact package for launch. Four potential MIC applications are described: Solar-thermal propulsion using H2 propellant, space based solar power generation for beaming power to Earth, a large space telescope, and solar electric generation for a manned lunar base. The first 3 applications use large MIC solar concentrating mirrors, while the 4th application uses a surface based array of solar cells on a magnetically levitated MIC structure to follow the sun. MIC space based mirrors can be very large and light in weight. A 300 meter diameter MIC mirror in orbit for example, would weigh 20 metric tons and MIC structures can be easily developed and tested on Earth at small scale in existing evacuated chambers followed by larger scale tests in the atmosphere, using a vacuum tight enclosure on the small diameter superconducting cable to prevent air leakage into the evacuated thermal insulation around the superconducting cable.

Status of advanced propulsion for space based orbital transfer vehicle

NASA Technical Reports Server (NTRS)

Cooper, Larry P.; Scheer, Dean D.

1986-01-01

A new Orbital Transfer Vehicle (OTV) propulsion system will be required to meet the needs of space missions beyond the mid-1990's. As envisioned, the advanced OTV will be used in conjunction with earth-to-orbit vehicles, Space Station, and Orbit Maneuvering Vehicle. The OTV will transfer men, large space structures, and conventional payloads between low earth and higher energy orbits. Space probes carried by the OTV will continue the exploration of the solar system. When lunar bases are established, the OTV will be their transportation link to earth. NASA is currently funding the development of technology for advanced propulsion concepts for future Orbital Transfer Vehicles. Progress in key areas during 1986 is presented.

Status of advanced propulsion for space based orbital transfer vehicle

NASA Technical Reports Server (NTRS)

Cooper, L. P.; Scheer, D. D.

1986-01-01

A new Orbital Transfer Vehicle (OTV) propulsion system will be required to meet the needs of space missions beyond the mid-1990's. As envisioned, the advanced OTV will be used in conjunction with Earth-to-orbit vehicles, Space Station, and Orbit Maneuvering Vehicle. The OTV will transfer men, large space structures, and conventional payloads between low Earth and higher energy orbits. Space probes carried by the OTV will continue the exploration of the solar system. When lunar bases are established, the OTV will be their transportation link to Earth. NASA is currently funding the development of technology for advanced propulsion concepts for future Orbital Transfer Vehicles. Progress in key areas during 1986 is presented.

Studies and analyses of the space shuttle main engine. Failure information propagation model data base and software

NASA Technical Reports Server (NTRS)

Tischer, A. E.

1987-01-01

The failure information propagation model (FIPM) data base was developed to store and manipulate the large amount of information anticipated for the various Space Shuttle Main Engine (SSME) FIPMs. The organization and structure of the FIPM data base is described, including a summary of the data fields and key attributes associated with each FIPM data file. The menu-driven software developed to facilitate and control the entry, modification, and listing of data base records is also discussed. The transfer of the FIPM data base and software to the NASA Marshall Space Flight Center is described. Complete listings of all of the data base definition commands and software procedures are included in the appendixes.

Laboratory development and testing of spacecraft diagnostics

NASA Astrophysics Data System (ADS)

Amatucci, William; Tejero, Erik; Blackwell, Dave; Walker, Dave; Gatling, George; Enloe, Lon; Gillman, Eric

2017-10-01

The Naval Research Laboratory's Space Chamber experiment is a large-scale laboratory device dedicated to the creation of large-volume plasmas with parameters scaled to realistic space plasmas. Such devices make valuable contributions to the investigation of space plasma phenomena under controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. However, in addition to investigations such as plasma wave and instability studies, such devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this talk, we will describe how the laboratory simulation of space plasmas made this development path possible. Work sponsored by the US Naval Research Laboratory Base Program.

Active Galaxies Educational Unit: An Educator's Guide with Activities in Science and Mathematics.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC.

As a part of its educational effort, the National Aeronautics and Space Administration (NASA) Education and Public Outreach group at Sonoma State University (SSU) has put together a series of activities based on the science of one of NASA's exciting space missions, the Gamma-ray Large Area Space Telescope (GLAST). GLAST is a NASA satellite planned…

The curious case of large-N expansions on a (pseudo)sphere

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

Polyakov, Alexander M.; Saleem, Zain H.; Stokes, James

We elucidate the large-N dynamics of one-dimensional sigma models with spherical and hyperbolic target spaces and find a duality between the Lagrange multiplier and the angular momentum. In the hyperbolic model we propose a new class of operators based on the irreducible representations of hyperbolic space. We also uncover unexpected zero modes which lead to the double scaling of the 1/N expansion and explore these modes using Gelfand-Dikiy equations.

The curious case of large-N expansions on a (pseudo)sphere

DOE PAGES

Polyakov, Alexander M.; Saleem, Zain H.; Stokes, James

2015-02-03

We elucidate the large-N dynamics of one-dimensional sigma models with spherical and hyperbolic target spaces and find a duality between the Lagrange multiplier and the angular momentum. In the hyperbolic model we propose a new class of operators based on the irreducible representations of hyperbolic space. We also uncover unexpected zero modes which lead to the double scaling of the 1/N expansion and explore these modes using Gelfand-Dikiy equations.

MIC: Magnetically Deployable Structures for Power, Propulsion, Processing, Habitats and Energy Storage at Manned Lunar Bases

NASA Astrophysics Data System (ADS)

Powell, James; Maise, George; Paniagua, John; Rather, John

2007-01-01

MIC (Magnetically Inflated Cables) is a new approach for robotically erecting very large, strong, rigid, and ultra-lightweight structures in space. MIC structures use a network of high current (SC) cables with attached high tensile strength Kevlar or Spectra tethers. MIC is launched as a compact package of coiled SC cables and tethers on a conventional launch vehicle. Once in space the SC cables are electrically energized. The resultant strong outwards magnetic forces expand them and the restraining tethers into a large structure, which can be 100's of meters in size. MIC structures can be configured for many different applications, including solar electric generation, solar thermal propulsion, energy storage, large space telescopes, magnetic shielding for astronauts, etc. The MIC technology components, including high temperature superconductors (HTS), thermal insulation, high strength tethers, and cryogenic refrigerators all exist commercially. Refrigeration requirements are very modest, on the order of 100 watts thermal per kilometer of MIC cable, with an input electric power to the refrigeration system of ~5 kW(e) per km. baseline MIC designs are described for a manned lunar base, including: 1) a 1 MW(e) solar electric system, 2) a high Isp (~900 seconds) solar thermal tug to transport 30 ton payloads between the Earth and the Moon, 3) a 2000 Megajoule electric energy storage system for peaking and emergency power, and 4) a large (~1 km) space telescope.

Space cryogenics components based on the thermomechanical effect - Vapor-liquid phase separation

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Frederking, T. H. K.

1989-01-01

Applications of the thermomechanical effect has been qualified including incorporation in large-scale space systems in the area of vapor-liquid phase separation (VLPS). The theory of the porous-plug phase separator is developed for the limit of a high thermal impedance of the solid-state grains. Extensions of the theory of nonlinear turbulent flow are presented based on experimental results.

The Role of Robots and Automation in Space

NASA Technical Reports Server (NTRS)

Heer, E.

1978-01-01

Advanced space transportation systems based on the shuttle and interim upper stage will open the way to the use of large-scale industrial and commercial systems in space. The role of robot and automation technology in the cost-effective implementation and operation of such systems in the next two decades is discussed. Planning studies initiated by NASA are described as applied to space exploration, global services, and space industrialization, and a forecast of potential missions in each category is presented. The appendix lists highlights of space robot technology from 1967 to the present.

An Analysis Methodology for the Gamma-ray Large Area Space Telescope

NASA Technical Reports Server (NTRS)

Morris, Robin D.; Cohen-Tanugi, Johann

2004-01-01

The Large Area Telescope (LAT) instrument on the Gamma Ray Large Area Space Telescope (GLAST) has been designed to detect high-energy gamma rays and determine their direction of incidence and energy. We propose a reconstruction algorithm based on recent advances in statistical methodology. This method, alternative to the standard event analysis inherited from high energy collider physics experiments, incorporates more accurately the physical processes occurring in the detector, and makes full use of the statistical information available. It could thus provide a better estimate of the direction and energy of the primary photon.

A Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST)

NASA Astrophysics Data System (ADS)

Conti, Alberto; Arenberg, Jonathan; Baldauf, Brian

2017-01-01

The “Search for Life” (direct imaging of earth-like planets) will require extremely stable telescopes with apertures in the 10 m to 20 m range. Such apertures are larger than what can be delivered to space using current or planned future launch vehicles. Building and assembling large telescopes in space is therefore likely to require not only multiple launches but importantly assembly in spce. As a result, space-based telescopes with large apertures will require major changes to our conventional telescope design and architecture.Here we report on the concept for the Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST) to demonstrates the on-orbit robotic and/or astronaut assembly of an optical telescope in space. MODEST is a proposed International Space Station (ISS demonstration that will make use of the standard Express Logistics Carriers (ELCs) and can mounted to one of a variety of ISS pallets.MODEST will provides significant risk reduction for the next generation of space observatories, and demonstrates the technology needed to assemble a six-mirror phased telescope. Key modest features include the use of an active primary optical surface with wavefront feedback control to allow on-orbit optimization, and the precise surface control to meet optical system wavefront and stability requirements.MODEST will also be used to evaluate advances in lightweight mirror and metering structure materials such as SiC or Carbon Fiber Reinforced Polymer (CFRP) that have excellent mechanical and thermal properties, e.g. high stiffness, high modulus, high thermal conductivity, and low thermal expansion. Mirrors built from these materials can be rapidly replicated in a highly cost effective manner, making them an excellent candidate for a low cost, high performance Optical Telescope Assembly paving the way for enabling affordable solutions for the next generation of large aperture space-based telescope.MODEST post-assembly value includes space, ground, and environmental studies, a testbed for new instruments, and a tool for student’s exploration of space.

Citygml and the Streets of New York - a Proposal for Detailed Street Space Modelling

NASA Astrophysics Data System (ADS)

Beil, C.; Kolbe, T. H.

2017-10-01

Three-dimensional semantic city models are increasingly used for the analysis of large urban areas. Until now the focus has mostly been on buildings. Nonetheless many applications could also benefit from detailed models of public street space for further analysis. However, there are only few guidelines for representing roads within city models. Therefore, related standards dealing with street modelling are examined and discussed. Nearly all street representations are based on linear abstractions. However, there are many use cases that require or would benefit from the detailed geometrical and semantic representation of street space. A variety of potential applications for detailed street space models are presented. Subsequently, based on related standards as well as on user requirements, a concept for a CityGML-compliant representation of street space in multiple levels of detail is developed. In the course of this process, the CityGML Transportation model of the currently valid OGC standard CityGML2.0 is examined to discover possibilities for further developments. Moreover, a number of improvements are presented. Finally, based on open data sources, the proposed concept is implemented within a semantic 3D city model of New York City generating a detailed 3D street space model for the entire city. As a result, 11 thematic classes, such as roadbeds, sidewalks or traffic islands are generated and enriched with a large number of thematic attributes.

Large perceptual distortions of locomotor action space occur in ground-based coordinates: Angular expansion and the large-scale horizontal-vertical illusion.

PubMed

Klein, Brennan J; Li, Zhi; Durgin, Frank H

2016-04-01

What is the natural reference frame for seeing large-scale spatial scenes in locomotor action space? Prior studies indicate an asymmetric angular expansion in perceived direction in large-scale environments: Angular elevation relative to the horizon is perceptually exaggerated by a factor of 1.5, whereas azimuthal direction is exaggerated by a factor of about 1.25. Here participants made angular and spatial judgments when upright or on their sides to dissociate egocentric from allocentric reference frames. In Experiment 1, it was found that body orientation did not affect the magnitude of the up-down exaggeration of direction, suggesting that the relevant orientation reference frame for this directional bias is allocentric rather than egocentric. In Experiment 2, the comparison of large-scale horizontal and vertical extents was somewhat affected by viewer orientation, but only to the extent necessitated by the classic (5%) horizontal-vertical illusion (HVI) that is known to be retinotopic. Large-scale vertical extents continued to appear much larger than horizontal ground extents when observers lay sideways. When the visual world was reoriented in Experiment 3, the bias remained tied to the ground-based allocentric reference frame. The allocentric HVI is quantitatively consistent with differential angular exaggerations previously measured for elevation and azimuth in locomotor space. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Large perceptual distortions of locomotor action space occur in ground-based coordinates: Angular expansion and the large-scale horizontal-vertical illusion

PubMed Central

Klein, Brennan J.; Li, Zhi; Durgin, Frank H.

2015-01-01

What is the natural reference frame for seeing large-scale spatial scenes in locomotor action space? Prior studies indicate an asymmetric angular expansion in perceived direction in large-scale environments: Angular elevation relative to the horizon is perceptually exaggerated by a factor of 1.5, whereas azimuthal direction is exaggerated by a factor of about 1.25. Here participants made angular and spatial judgments when upright or on their sides in order to dissociate egocentric from allocentric reference frames. In Experiment 1 it was found that body orientation did not affect the magnitude of the up-down exaggeration of direction, suggesting that the relevant orientation reference frame for this directional bias is allocentric rather than egocentric. In Experiment 2, the comparison of large-scale horizontal and vertical extents was somewhat affected by viewer orientation, but only to the extent necessitated by the classic (5%) horizontal-vertical illusion (HVI) that is known to be retinotopic. Large-scale vertical extents continued to appear much larger than horizontal ground extents when observers lay sideways. When the visual world was reoriented in Experiment 3, the bias remained tied to the ground-based allocentric reference frame. The allocentric HVI is quantitatively consistent with differential angular exaggerations previously measured for elevation and azimuth in locomotor space. PMID:26594884

A laser-optical system to re-enter or lower low Earth orbit space debris

NASA Astrophysics Data System (ADS)

Phipps, Claude R.

2014-01-01

Collisions among existing Low Earth Orbit (LEO) debris are now a main source of new debris, threatening future use of LEO space. Due to their greater number, small (1-10 cm) debris are the main threat, while large (>10 cm) objects are the main source of new debris. Flying up and interacting with each large object is inefficient due to the energy cost of orbit plane changes, and quite expensive per object removed. Strategically, it is imperative to remove both small and large debris. Laser-Orbital-Debris-Removal (LODR), is the only solution that can address both large and small debris. In this paper, we briefly review ground-based LODR, and discuss how a polar location can dramatically increase its effectiveness for the important class of sun-synchronous orbit (SSO) objects. With 20% clear weather, a laser-optical system at either pole could lower the 8-ton ENVISAT by 40 km in about 8 weeks, reducing the hazard it represents by a factor of four. We also discuss the advantages and disadvantages of a space-based LODR system. We estimate cost per object removed for these systems. International cooperation is essential for designing, building and operating any such system.

Modified independent modal space control method for active control of flexible systems

NASA Technical Reports Server (NTRS)

Baz, A.; Poh, S.

1987-01-01

A modified independent modal space control (MIMSC) method is developed for designing active vibration control systems for large flexible structures. The method accounts for the interaction between the controlled and residual modes. It incorporates also optimal placement procedures for selecting the optimal locations of the actuators in the structure in order to minimize the structural vibrations as well as the actuation energy. The MIMSC method relies on an important feature which is based on time sharing of a small number of actuators, in the modal space, to control effectively a large number of modes. Numerical examples are presented to illustrate the application of the method to generic flexible systems. The results obtained suggest the potential of the devised method in designing efficient active control systems for large flexible structures.

Modeling space-time correlations of velocity fluctuations in wind farms

NASA Astrophysics Data System (ADS)

Lukassen, Laura J.; Stevens, Richard J. A. M.; Meneveau, Charles; Wilczek, Michael

2018-07-01

An analytical model for the streamwise velocity space-time correlations in turbulent flows is derived and applied to the special case of velocity fluctuations in large wind farms. The model is based on the Kraichnan-Tennekes random sweeping hypothesis, capturing the decorrelation in time while including a mean wind velocity in the streamwise direction. In the resulting model, the streamwise velocity space-time correlation is expressed as a convolution of the pure space correlation with an analytical temporal decorrelation kernel. Hence, the spatio-temporal structure of velocity fluctuations in wind farms can be derived from the spatial correlations only. We then explore the applicability of the model to predict spatio-temporal correlations in turbulent flows in wind farms. Comparisons of the model with data from a large eddy simulation of flow in a large, spatially periodic wind farm are performed, where needed model parameters such as spatial and temporal integral scales and spatial correlations are determined from the large eddy simulation. Good agreement is obtained between the model and large eddy simulation data showing that spatial data may be used to model the full temporal structure of fluctuations in wind farms.

Ozone Depletion Caused by Rocket Engine Emissions: A Fundamental Limit on the Scale and Viability of Space-Based Geoengineering Schemes

NASA Astrophysics Data System (ADS)

Ross, M. N.; Toohey, D.

2008-12-01

Emissions from solid and liquid propellant rocket engines reduce global stratospheric ozone levels. Currently ~ one kiloton of payloads are launched into earth orbit annually by the global space industry. Stratospheric ozone depletion from present day launches is a small fraction of the ~ 4% globally averaged ozone loss caused by halogen gases. Thus rocket engine emissions are currently considered a minor, if poorly understood, contributor to ozone depletion. Proposed space-based geoengineering projects designed to mitigate climate change would require order of magnitude increases in the amount of material launched into earth orbit. The increased launches would result in comparable increases in the global ozone depletion caused by rocket emissions. We estimate global ozone loss caused by three space-based geoengineering proposals to mitigate climate change: (1) mirrors, (2) sunshade, and (3) space-based solar power (SSP). The SSP concept does not directly engineer climate, but is touted as a mitigation strategy in that SSP would reduce CO2 emissions. We show that launching the mirrors or sunshade would cause global ozone loss between 2% and 20%. Ozone loss associated with an economically viable SSP system would be at least 0.4% and possibly as large as 3%. It is not clear which, if any, of these levels of ozone loss would be acceptable under the Montreal Protocol. The large uncertainties are mainly caused by a lack of data or validated models regarding liquid propellant rocket engine emissions. Our results offer four main conclusions. (1) The viability of space-based geoengineering schemes could well be undermined by the relatively large ozone depletion that would be caused by the required rocket launches. (2) Analysis of space- based geoengineering schemes should include the difficult tradeoff between the gain of long-term (~ decades) climate control and the loss of short-term (~ years) deep ozone loss. (3) The trade can be properly evaluated only if our understanding of the stratospheric impact of rocket emissions is significantly improved. (4) Such an improved understanding requires a concerted effort of research including new in situ measurements in a variety of rocket plumes and a multi-scale modeling program similar in scope to the effort required to address the climate and ozone impacts of aircraft emissions.

Parallel computing method for simulating hydrological processesof large rivers under climate change

NASA Astrophysics Data System (ADS)

Wang, H.; Chen, Y.

2016-12-01

Climate change is one of the proverbial global environmental problems in the world.Climate change has altered the watershed hydrological processes in time and space distribution, especially in worldlarge rivers.Watershed hydrological process simulation based on physically based distributed hydrological model can could have better results compared with the lumped models.However, watershed hydrological process simulation includes large amount of calculations, especially in large rivers, thus needing huge computing resources that may not be steadily available for the researchers or at high expense, this seriously restricted the research and application. To solve this problem, the current parallel method are mostly parallel computing in space and time dimensions.They calculate the natural features orderly thatbased on distributed hydrological model by grid (unit, a basin) from upstream to downstream.This articleproposes ahigh-performancecomputing method of hydrological process simulation with high speedratio and parallel efficiency.It combinedthe runoff characteristics of time and space of distributed hydrological model withthe methods adopting distributed data storage, memory database, distributed computing, parallel computing based on computing power unit.The method has strong adaptability and extensibility,which means it canmake full use of the computing and storage resources under the condition of limited computing resources, and the computing efficiency can be improved linearly with the increase of computing resources .This method can satisfy the parallel computing requirements ofhydrological process simulation in small, medium and large rivers.

Mediating Transnational Spaces: International Students and Intercultural Responsibility

ERIC Educational Resources Information Center

Tran, Ly Thi; Vu, Thao Thi Phuong

2017-01-01

Despite the significant body of literature on international students' intercultural development, the core issue of how they see their own responsibility in transnational intercultural spaces is largely neglected. This paper addresses this paucity by examining the intercultural responsibility perceived by international students. It is based on a…

Retrieving the aerosol lidar ratio profile by combining ground- and space-based elastic lidars.

PubMed

Feiyue, Mao; Wei, Gong; Yingying, Ma

2012-02-15

The aerosol lidar ratio is a key parameter for the retrieval of aerosol optical properties from elastic lidar, which changes largely for aerosols with different chemical and physical properties. We proposed a method for retrieving the aerosol lidar ratio profile by combining simultaneous ground- and space-based elastic lidars. The method was tested by a simulated case and a real case at 532 nm wavelength. The results demonstrated that our method is robust and can obtain accurate lidar ratio and extinction coefficient profiles. Our method can be useful for determining the local and global lidar ratio and validating space-based lidar datasets.

Status of High Data Rate Intersatellite Laser Communication as an Enabler for Earth and Space Science

NASA Astrophysics Data System (ADS)

Heine, F.; Zech, H.; Motzigemba, M.

2017-12-01

Space based laser communication is supporting earth observation and science missions with Gbps data download capabilities. Currently the Sentinel 1 and Sentinel 2 spacecrafts from the Copernicus earth observation program of the European Commission are using the Gbps laser communication links developed by Tesat Spacecom to download low latency data products via a commercial geostationary laser relay station- the European Data Relay Service- (EDRS) as a standard data path, in parallel to the conventional radio frequency links. The paper reports on the status of high bandwidth space laser communication as an enabler for small and large space science missions ranging from cube sat applications in low earth orbit to deep space missions. Space based laser communication has left the experimental phase and will support space science missions with unprecedented data rates.

The development and testing of the Lens Antenna Deployment Demonstration (LADD) test article

NASA Technical Reports Server (NTRS)

Pugh, Mark L.; Denton, Robert J., Jr.; Strange, Timothy J.

1993-01-01

The USAF Rome Laboratory and NASA Marshall Space Flight Center, through contract to Grumman Corporation, have developed a space-qualifiable test article for the Strategic Defense Initiative Organization to demonstrate the critical structural and mechanical elements of single-axis roll-out membrane deployment for Space Based Radar (SBR) applications. The Lens Antenna Deployment Demonstration (LADD) test article, originally designed as a shuttle-attached flight experiment, is a large precision space structure which is representative of operational designs for space-fed lens antennas. Although the flight experiment was cancelled due to funding constraints and major revisions in the Strategic Defense System (SDS) architecture, development of this test article was completed in June 1989. To take full advantage of the existence of this unique structure, a series of ground tests are proposed which include static, dynamic, and thermal measurements in a simulated space environment. An equally important objective of these tests is the verification of the analytical tools used to design and develop large precision space structures.

Parametric Cost Models for Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney

2010-01-01

Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

Ground-Based High-Power Microwave Decoy Discrimination System.

DTIC Science & Technology

1987-12-23

understanding of plasma instabilities, self-induced magnetic effects , space - charge considerations, production of ion currents, etc. 3.3.4 Cross-Field...breakdown, due to small potential differences. Interaction volumes can therefore be large, avoiding breakdown and space - charge effects (at the price...the interference of the incident and reflected wave, and by the electrostatic forces of the surface (positive) and space charge (negative) trapped in

Object-based selection in the Baylis and Driver (1993) paradigm is subject to space-based attentional modulation.

PubMed

Müller, Hermann J; O'Grady, Rebecca; Krummenacher, Joseph; Heller, Dieter

2008-11-01

Three experiments re-examined Baylis and Driver's (1993) strong evidence for object-based selection, that making relative apex location judgments is harder between two objects than within a single object, with object (figure-ground) segmentation determined solely by color-based perceptual set. Using variations of the Baylis and Driver paradigm, the experiments replicated a two-object cost. However, they also showed a large part of the two-object cost to be attributable to space-based factors, though there remained an irreducible cost consistent with 'true' object-based selection.

CeSiCò - a new technology for lightweight and cost effective space instruments structures and mirrors

NASA Astrophysics Data System (ADS)

Devilliers, Christophe; Krödel, Matthias

2017-11-01

Alcatel Alenia Space and ECM have jointly developed a new ceramic material to produce lightweight, stiff, stable and cost effective structures and mirrors for space instrument the CesicÒ. Its intrinsic properties, added to ample manufacturing capabilities allow to manufacture stiff and lightweight cost effective mirrors and structure for space instruments. Different scale 1 flight representative CesicÒ optical structures have been manufactured and successfully tested under very strong dynamic environment and cryogenic condition down to 30K CesicÒ is also envisaged for large and lightweight space telescopes mirrors, a large CesicÒ 1 meter class mirror with an area mass of less than 25 Kg/m2 has been sized again launch loads and WFE performance and manufactured. CesicÒ applicability for large focal plane have been demonstrated through different scale 1 breadboards. Based on these successful results, AlcatelAleniaSpace and ECM are now in position to propose for space this technology with new innovative concepts thanks to the CesicÒ manufacturing capabilities. CesicÒ has therefore been selected for the structure and mirrors parts of a flight instrument payload and the manufacturing of the flight hardware is already underway. An high temperature high gain lightweight antenna breadboard is also under manufacturing for Bepi colombo mission. CesicÒ is therefore a good candidate for future challenging space instruments and is currently proposed for Japan and US space projects.

Improvisation as a Curricular Metaphor: Imagining Education for a Rural Creative Class

ERIC Educational Resources Information Center

Corbett, Michael

2013-01-01

Rural communities contain a largely unacknowledged innovative capacity founded on improvisational traditions. These traditions may be rooted in work practices in agriculture and other rurally-based productive activities but today they have expanded into other lifeworld locations, particularly virtual spaces that accelerate time-space compression.…

Visualization of Earth and Space Science Data at JPL's Science Data Processing Systems Section

NASA Technical Reports Server (NTRS)

Green, William B.

1996-01-01

This presentation will provide an overview of systems in use at NASA's Jet Propulsion Laboratory for processing data returned by space exploration and earth observations spacecraft. Graphical and visualization techniques used to query and retrieve data from large scientific data bases will be described.

Technology Prioritized for HA/DR: A Space Based ISR Solution

DTIC Science & Technology

2014-04-01

record, with history demonstrating example after example where we picked wrong.11 Both large and small wars provide a different scenario for ISR...Revolution in Understanding the Wave Climate, 15 years of progress in radar altimetry Symposium, Venice , Italy, 2006. Charter on Space and Major Disasters

The LEO Archipelago: A system of earth-rings for communications, mass-transport to space, solar power, and control of global warming

NASA Astrophysics Data System (ADS)

Meulenberg, Andrew; Karthik Balaji, P. S.

2011-06-01

Man's quest to get into space is hindered by major problems (e.g., system-development and capital costs, expense of putting mass into orbit, trapped-radiation belts, and environmental impact of a large increase in rocket launches). A multi-purpose low-earth-orbit system of rings circling the earth - the "LEO ARCHIPELAGO TM" - is proposed as a means of solving or bypassing many of them. A fiber-optic ring about the earth would be an initial testing and developmental stage for the Ring Systems, while providing cash-flow through a LEO-based, high-band-width, world-wide communication system. A low-earth-orbit-based space-elevator system, "Sling-on-a-Ring TM", is proposed as the crucial developmental stage of the LEO Archipelago. Being a LEO-based heavy-mass lifter, rather than earth- or GEO-based, it is much less massive and therefore less costly than other proposed space-elevators. With the advent of lower-cost, higher-mass transport to orbit, the options for further space development (e.g., space solar power, radiation, and space-debris dampers, sun shades, and permanent LEO habitation) are greatly expanded. This paper provides an update of the Sling-on-a-Ring concept in terms of new materials, potential applications, and trade-offs associated with an earlier model. The impact of Colossal Carbon Tubes, CCT, a new material with high tensile strength, extremely-low density, and other favorable properties, and other new technologies (e.g., solar-powered lasers, power beaming to near-space and earth, and thermal-control systems) on the development of associated LEO-Ring systems is also explored. The material's effect on the timeline for the system development indicates the feasibility of near-term implementation of the system (possibly within the decade). The Sling-on-a-Ring can provide a less-expensive, environment-friendly mode of access to space. This would pave the way (via eventual operation at >1000 t per day by 2050) for large scale development of space-based technologies.

Bubbles, voids, and bumps in time: The new cosmology

NASA Astrophysics Data System (ADS)

Cornell, James

The history and current status of theoretical and observational cosmology are examined in chapters based on the Lowell Lectures, given in Boston and Washington DC in spring 1987. Topics addressed include the Aristotelian, Copernican, Newtonian, and Einsteinian universes; the measurement of the universe (redshifts and standard candles); mapping the universe (slices and bubbles); dark matter and missing mass; and the big bang and cosmic inflation. Six basic outstanding problems are identified, and the potential contributions of planned ground-based and space observatories to their solution are discussed. Particular attention is given to CCD detectors for large ground-based telescopes, the VLA, VLBI arrays, the ESO Very Large Telescope, the 10-m Keck telescope on Mauna Kea, the Hubble Space Telescope, the Gamma-Ray Observatory, and the Advanced X-ray Astrophysics Facility.

Screen Space Ambient Occlusion Based Multiple Importance Sampling for Real-Time Rendering

NASA Astrophysics Data System (ADS)

Zerari, Abd El Mouméne; Babahenini, Mohamed Chaouki

2018-03-01

We propose a new approximation technique for accelerating the Global Illumination algorithm for real-time rendering. The proposed approach is based on the Screen-Space Ambient Occlusion (SSAO) method, which approximates the global illumination for large, fully dynamic scenes at interactive frame rates. Current algorithms that are based on the SSAO method suffer from difficulties due to the large number of samples that are required. In this paper, we propose an improvement to the SSAO technique by integrating it with a Multiple Importance Sampling technique that combines a stratified sampling method with an importance sampling method, with the objective of reducing the number of samples. Experimental evaluation demonstrates that our technique can produce high-quality images in real time and is significantly faster than traditional techniques.

Comparison of Water Vapor Measurements from Ground-based and Space-based GPS Atmospheric Remote Sensing Techniques

NASA Astrophysics Data System (ADS)

Colon-Pagan, Ian; Kuo, Ying-Hwa

2008-10-01

In this study, we compare precipitable water vapor (PWV) values from ground-based GPS water vapor sensing and COSMIC radio occultation (RO) measurements over the Caribbean Sea, Gulf of Mexico, and United States regions as well as global analyses from NCEP and ECMWF models. The results show good overall agreement; however, the PWV values estimated by ground-based GPS receivers tend to have a slight dry bias for low PWV values and a slight wet bias for higher PWV values, when compared with GPS RO measurements and global analyses. An application of a student T-test indicates that there is a significant difference between both ground- and space-based GPS measured datasets. The dry bias associated with space-based GPS is attributed to the missing low altitude data, where the concentration of water vapor is large. The close agreements between space-based and global analyses are due to the fact that these global analyses assimilate space-based GPS RO data from COSMIC, and the retrieval of water vapor profiles from space-based technique requires the use of global analyses as the first guess. This work is supported by UCAR SOARS and a grant from the National Oceanic and Atmospheric Administration, Educational Partnership Program under the cooperative agreement NA06OAR4810187.

Simulation study on dynamics model of two kinds of on-orbit soft-contact mechanism

NASA Astrophysics Data System (ADS)

Ye, X.; Dong, Z. H.; Yang, F.

2018-05-01

Aiming at the problem that the operating conditions of the space manipulator is harsh and the space manipulator could not bear the large collision momentum, this paper presents a new concept and technical method, namely soft contact technology. Based on ADAMS dynamics software, this paper compares and simulates the mechanism model of on-orbit soft-contact mechanism based on the bionic model and the integrated double joint model. The main purpose is to verify the path planning ability and the momentum buffering ability based on the different design concept mechanism. The simulation results show that both the two mechanism models have the path planning function before the space target contact, and also has the momentum buffer and controllability during the space target contact process.

LSST system analysis and integration task for an advanced science and application space platform

NASA Technical Reports Server (NTRS)

1980-01-01

To support the development of an advanced science and application space platform (ASASP) requirements of a representative set of payloads requiring large separation distances selected from the Science and Applications Space Platform data base. These payloads were a 100 meter diameter atmospheric gravity wave antenna, a 100 meter by 100 meter particle beam injection experiment, a 2 meter diameter, 18 meter long astrometric telescope, and a 15 meter diameter, 35 meter long large ambient deployable IR telescope. A low earth orbit at 500 km altitude and 56 deg inclination was selected as being the best compromise for meeting payload requirements. Platform subsystems were defined which would support the payload requirements and a physical platform concept was developed. Structural system requirements which included utilities accommodation, interface requirements, and platform strength and stiffness requirements were developed. An attitude control system concept was also described. The resultant ASASP concept was analyzed and technological developments deemed necessary in the area of large space systems were recommended.

A new approach for vibration control in large space structures

NASA Technical Reports Server (NTRS)

Kumar, K.; Cochran, J. E., Jr.

1987-01-01

An approach for augmenting vibration damping characteristics in space structures with large panels is presented. It is based on generation of bending moments rather than forces. The moments are generated using bimetallic strips, suitably mounted at selected stations on both sides of the large panels, under the influence of differential solar heating, giving rise to thermal gradients and stresses. The collocated angular velocity sensors are utilized in conjunction with mini-servos to regulate the control moments by flipping the bimetallic strips. A simple computation of the rate of dissipation of vibrational energy is undertaken to assess the effectiveness of the proposed approach.

Radiation risk and human space exploration.

PubMed

Schimmerling, W; Cucinotta, F A; Wilson, J W

2003-01-01

Radiation protection is essential to enable humans to live and work safely in space. Predictions about the nature and magnitude of the risks posed by space radiation are subject to very large uncertainties. Prudent use of worst-case scenarios may impose unacceptable constraints on shielding mass for spacecraft or habitats, tours of duty of crews on Space Station, and on the radius and duration of sorties on planetary surfaces. The NASA Space Radiation Health Program has been devised to develop the knowledge required to accurately predict and to efficiently manage radiation risk. The knowledge will be acquired by means of a peer-reviewed, largely ground-based and investigator-initiated, basic science research program. The NASA Strategic Plan to accomplish these objectives in a manner consistent with the high priority assigned to the protection and health maintenance of crews will be presented. Published by Elsevier Science Ltd on behalf of COSPAR.

Radiation risk and human space exploration

NASA Technical Reports Server (NTRS)

Schimmerling, W.; Cucinotta, F. A.; Wilson, J. W.

2003-01-01

Radiation protection is essential to enable humans to live and work safely in space. Predictions about the nature and magnitude of the risks posed by space radiation are subject to very large uncertainties. Prudent use of worst-case scenarios may impose unacceptable constraints on shielding mass for spacecraft or habitats, tours of duty of crews on Space Station, and on the radius and duration of sorties on planetary surfaces. The NASA Space Radiation Health Program has been devised to develop the knowledge required to accurately predict and to efficiently manage radiation risk. The knowledge will be acquired by means of a peer-reviewed, largely ground-based and investigator-initiated, basic science research program. The NASA Strategic Plan to accomplish these objectives in a manner consistent with the high priority assigned to the protection and health maintenance of crews will be presented. Published by Elsevier Science Ltd on behalf of COSPAR.

Strongly contracted canonical transformation theory

NASA Astrophysics Data System (ADS)

Neuscamman, Eric; Yanai, Takeshi; Chan, Garnet Kin-Lic

2010-01-01

Canonical transformation (CT) theory describes dynamic correlation in multireference systems with large active spaces. Here we discuss CT theory's intruder state problem and why our previous approach of overlap matrix truncation becomes infeasible for sufficiently large active spaces. We propose the use of strongly and weakly contracted excitation operators as alternatives for dealing with intruder states in CT theory. The performance of these operators is evaluated for the H2O, N2, and NiO molecules, with comparisons made to complete active space second order perturbation theory and Davidson-corrected multireference configuration interaction theory. Finally, using a combination of strongly contracted CT theory and orbital-optimized density matrix renormalization group theory, we evaluate the singlet-triplet gap of free base porphin using an active space containing all 24 out-of-plane 2p orbitals. Modeling dynamic correlation with an active space of this size is currently only possible using CT theory.

Future Photovoltaic Power Generation for Space-Based Power Utilities

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Landis, Geoffrey; Hepp, Aloysius; Raffaelle, Ryne

2002-01-01

This paper discusses requirements for large earth orbiting power stations that can serve as central utilities for other orbiting spacecraft, or for beaming power to the earth itself. The current state of the art of space solar cells, and a variety of both evolving thin film cells as well as new technologies that may impact the future choice of space solar cells for high power mission applications are addressed.

FIR Detector Sensitivity, Dynamic Range, and Multiplexing Requirements for the Origins Space Telescope (OST)

NASA Astrophysics Data System (ADS)

Staguhn, Johannes G.

2018-05-01

Spectroscopic, cold, space-based mid-to-far-infrared (FIR) missions, such as the Origins Space Telescope, will require large (tens of kilopixels), ultra-sensitive FIR detector arrays with sufficient dynamic range and high-density multiplexing schemes for the readout, in order to optimize the scientific return while staying within a realistic cost range. Issues like power consumption of multiplexers and their readout are significantly more important for space missions than they are for ground-based or suborbital applications. In terms of the detectors and their configuration into large arrays, significant development efforts are needed even for both of the most mature candidate superconducting detector technologies, namely transition edge sensors and (microwave) kinetic inductance detectors. Here we explore both practical and fundamental limits for those technologies in order to lay out a realistic path forward for both technologies. We conclude that beyond the need to enhance the detector sensitivities and pixel numbers by about an order of magnitude over currently existing devices, improved concepts for larger dynamic range and multiplexing density will be needed in order to optimize the scientific return of future cold FIR space missions. Background-limited, very high spectral resolution instruments will require photon-counting detectors.

Space astronomical telescopes and instruments; Proceedings of the Meeting, Orlando, FL, Apr. 1-4, 1991

NASA Astrophysics Data System (ADS)

Bely, Pierre Y.; Breckinridge, James B.

The present volume on space astronomical telescopes and instruments discusses lessons from the HST, telescopes on the moon, future space missions, and mirror fabrication and active control. Attention is given to the in-flight performance of the Goddard high-resolution spectrograph of the HST, the initial performance of the high-speed photometer, results from HST fine-guidance sensors, and reconstruction of the HST mirror figure from out-of-focus stellar images. Topics addressed include system concepts for a large UV/optical/IR telescope on the moon, optical design considerations for next-generation space and lunar telescopes, the implications of lunar dust for astronomical observatories, and lunar liquid-mirror telescopes. Also discussed are space design considerations for the Space Infrared Telescope Facility, the Hubble extrasolar planet interferometer, Si:Ga focal-plane arrays for satellite and ground-based telescopes, microchannel-plate detectors for space-based astronomy, and a method for making ultralight primary mirrors.

Analysis and testing of a soft actuation system for segmented reflector articulation and isolation

NASA Technical Reports Server (NTRS)

Jandura, Louise; Agronin, Michael L.

1991-01-01

Segmented reflectors have been proposed for space-based applications such as optical communication and large-diameter telescopes. An actuation system for mirrors in a space-based segmented mirror array has been developed as part of the National Aeronautics and Space Administration-sponsored Precision Segmented Reflector program. The actuation system, called the Articulated Panel Module (APM), articulates a mirror panel in 3 degrees of freedom in the submicron regime, isolates the panel from structural motion, and simplifies space assembly of the mirrors to the reflector backup truss. A breadboard of the APM has been built and is described. Three-axis modeling, analysis, and testing of the breadboard is discussed.

Guiding Conformation Space Search with an All-Atom Energy Potential

PubMed Central

Brunette, TJ; Brock, Oliver

2009-01-01

The most significant impediment for protein structure prediction is the inadequacy of conformation space search. Conformation space is too large and the energy landscape too rugged for existing search methods to consistently find near-optimal minima. To alleviate this problem, we present model-based search, a novel conformation space search method. Model-based search uses highly accurate information obtained during search to build an approximate, partial model of the energy landscape. Model-based search aggregates information in the model as it progresses, and in turn uses this information to guide exploration towards regions most likely to contain a near-optimal minimum. We validate our method by predicting the structure of 32 proteins, ranging in length from 49 to 213 amino acids. Our results demonstrate that model-based search is more effective at finding low-energy conformations in high-dimensional conformation spaces than existing search methods. The reduction in energy translates into structure predictions of increased accuracy. PMID:18536015

Superconducting linear actuator

NASA Technical Reports Server (NTRS)

Johnson, Bruce; Hockney, Richard

1993-01-01

Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

NSF's Perspective on Space Weather Research for Building Forecasting Capabilities

NASA Astrophysics Data System (ADS)

Bisi, M. M.; Pulkkinen, A. A.; Bisi, M. M.; Pulkkinen, A. A.; Webb, D. F.; Oughton, E. J.; Azeem, S. I.

2017-12-01

Space weather research at the National Science Foundation (NSF) is focused on scientific discovery and on deepening knowledge of the Sun-Geospace system. The process of maturation of knowledge base is a requirement for the development of improved space weather forecast models and for the accurate assessment of potential mitigation strategies. Progress in space weather forecasting requires advancing in-depth understanding of the underlying physical processes, developing better instrumentation and measurement techniques, and capturing the advancements in understanding in large-scale physics based models that span the entire chain of events from the Sun to the Earth. This presentation will provide an overview of current and planned programs pertaining to space weather research at NSF and discuss the recommendations of the Geospace Section portfolio review panel within the context of space weather forecasting capabilities.

A transformed path integral approach for solution of the Fokker-Planck equation

NASA Astrophysics Data System (ADS)

Subramaniam, Gnana M.; Vedula, Prakash

2017-10-01

A novel path integral (PI) based method for solution of the Fokker-Planck equation is presented. The proposed method, termed the transformed path integral (TPI) method, utilizes a new formulation for the underlying short-time propagator to perform the evolution of the probability density function (PDF) in a transformed computational domain where a more accurate representation of the PDF can be ensured. The new formulation, based on a dynamic transformation of the original state space with the statistics of the PDF as parameters, preserves the non-negativity of the PDF and incorporates short-time properties of the underlying stochastic process. New update equations for the state PDF in a transformed space and the parameters of the transformation (including mean and covariance) that better accommodate nonlinearities in drift and non-Gaussian behavior in distributions are proposed (based on properties of the SDE). Owing to the choice of transformation considered, the proposed method maps a fixed grid in transformed space to a dynamically adaptive grid in the original state space. The TPI method, in contrast to conventional methods such as Monte Carlo simulations and fixed grid approaches, is able to better represent the distributions (especially the tail information) and better address challenges in processes with large diffusion, large drift and large concentration of PDF. Additionally, in the proposed TPI method, error bounds on the probability in the computational domain can be obtained using the Chebyshev's inequality. The benefits of the TPI method over conventional methods are illustrated through simulations of linear and nonlinear drift processes in one-dimensional and multidimensional state spaces. The effects of spatial and temporal grid resolutions as well as that of the diffusion coefficient on the error in the PDF are also characterized.

Low Cost Large Core Vehicle Structures Assessment

NASA Technical Reports Server (NTRS)

Hahn, Steven E.

1998-01-01

Boeing Information, Space, and Defense Systems executed a Low Cost Large Core Vehicle Structures Assessment (LCLCVSA) under contract to NASA Marshall Space Flight Center (MSFC) between November 1997 and March 1998. NASA is interested in a low-cost launch vehicle, code named Magnum, to place heavy payloads into low earth orbit for missions such as a manned mission to Mars, a Next Generation Space Telescope, a lunar-based telescope, the Air Force's proposed space based laser, and large commercial satellites. In this study, structural concepts with the potential to reduce fabrication costs were evaluated in application to the Magnum Launch Vehicle (MLV) and the Liquid Fly Back Booster (LFBB) shuttle upgrade program. Seventeen concepts were qualitatively evaluated to select four concepts for more in-depth study. The four structural concepts selected were: an aluminum-lithium monocoque structure, an aluminum-lithium machined isogrid structure, a unitized composite sandwich structure, and a unitized composite grid structure. These were compared against a baseline concept based on the Space Shuttle External Tank (ET) construction. It was found that unitized composite structures offer significant cost and weight benefits to MLV structures. The limited study of application to LFBB structures indicated lower, but still significant benefits. Technology and facilities development roadmaps to prepare the approaches studied for application to MLV and LFBB were constructed. It was found that the cost and schedule to develop these approaches were in line with both MLV and LFBB development schedules. Current Government and Boeing programs which address elements of the development of the technologies identified are underway. It is recommended that NASA devote resources in a timely fashion to address the specific elements related to MLV and LFBB structures.

A Fourier-based compressed sensing technique for accelerated CT image reconstruction using first-order methods.

PubMed

Choi, Kihwan; Li, Ruijiang; Nam, Haewon; Xing, Lei

2014-06-21

As a solution to iterative CT image reconstruction, first-order methods are prominent for the large-scale capability and the fast convergence rate [Formula: see text]. In practice, the CT system matrix with a large condition number may lead to slow convergence speed despite the theoretically promising upper bound. The aim of this study is to develop a Fourier-based scaling technique to enhance the convergence speed of first-order methods applied to CT image reconstruction. Instead of working in the projection domain, we transform the projection data and construct a data fidelity model in Fourier space. Inspired by the filtered backprojection formalism, the data are appropriately weighted in Fourier space. We formulate an optimization problem based on weighted least-squares in the Fourier space and total-variation (TV) regularization in image space for parallel-beam, fan-beam and cone-beam CT geometry. To achieve the maximum computational speed, the optimization problem is solved using a fast iterative shrinkage-thresholding algorithm with backtracking line search and GPU implementation of projection/backprojection. The performance of the proposed algorithm is demonstrated through a series of digital simulation and experimental phantom studies. The results are compared with the existing TV regularized techniques based on statistics-based weighted least-squares as well as basic algebraic reconstruction technique. The proposed Fourier-based compressed sensing (CS) method significantly improves both the image quality and the convergence rate compared to the existing CS techniques.

Hybrid Electrostatic/Flextensional Mirror for Lightweight, Large-Aperture, and Cryogenic Space Telescopes

NASA Technical Reports Server (NTRS)

Patrick, Brian; Moore, James; Hackenberger, Wesley; Jiang, Xiaoning

2013-01-01

A lightweight, cryogenically capable, scalable, deformable mirror has been developed for space telescopes. This innovation makes use of polymer-based membrane mirror technology to enable large-aperture mirrors that can be easily launched and deployed. The key component of this innovation is a lightweight, large-stroke, cryogenic actuator array that combines the high degree of mirror figure control needed with a large actuator influence function. The latter aspect of the innovation allows membrane mirror figure correction with a relatively low actuator density, preserving the lightweight attributes of the system. The principal components of this technology are lightweight, low-profile, high-stroke, cryogenic-capable piezoelectric actuators based on PMN-PT (piezoelectric lead magnesium niobate-lead titanate) single-crystal configured in a flextensional actuator format; high-quality, low-thermal-expansion polymer membrane mirror materials developed by NeXolve; and electrostatic coupling between the membrane mirror and the piezoelectric actuator assembly to minimize problems such as actuator print-through.

Surgical resection of large encephalocele: a report of two cases and consideration of resectability based on developmental morphology.

PubMed

Ohba, Hideo; Yamaguchi, Satoshi; Sadatomo, Takashi; Takeda, Masaaki; Kolakshyapati, Manish; Kurisu, Kaoru

2017-03-01

The first-line treatment of encephalocele is reduction of herniated structures. Large irreducible encephalocele entails resection of the lesion. In such case, it is essential to ascertain preoperatively if the herniated structure encloses critical venous drainage. Two cases of encephalocele presenting with large occipital mass underwent magnetic resonance (MR) imaging. In first case, the skin mass enclosed the broad space containing cerebrospinal fluid and a part of occipital lobe and cerebellum. The second case had occipital mass harboring a large portion of cerebrum enclosing dilated ventricular space. Both cases had common venous anomalies such as split superior sagittal sinus and high-positioned torcular herophili. They underwent resection of encephalocele without subsequent venous congestion. We could explain the pattern of venous anomalies in encephalocele based on normal developmental theory. Developmental theory connotes that major dural sinuses cannot herniate into the sac of encephalocele. Irrespective to its size, encephalocele can be resected safely at the neck without subsequent venous congestion.

Development of television tubes for the large space telescope

NASA Technical Reports Server (NTRS)

Lowrance, J. L.; Zucchino, P.

1971-01-01

Princeton Observatory has been working for several years under NASA sponsorship to develop television type sensors to use in place of photographic film for space astronomy. The performance of an SEC-vidicon with a 25 mm x 25 mm active area, MgF2 window, and bi-alkali photocathode is discussed. Results from ground based use on the Coude spectrograph of the 200-inch Hale telescope are included. The intended use of this tube in an echelle spectrograph sounding rocket payload and on Stratoscope 2 for direct high resolution imagery is also discussed. The paper also discusses the large space telescope image sensor requirements and the development of a larger television tube for this mission.

Large File Transfers from Space Using Multiple Ground Terminals and Delay-Tolerant Networking

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Paulsen, Phillip; Stewart, Dave; Eddy, Wesley; McKim, James; Taylor, John; Lynch, Scott; Heberle, Jay; Northam, James; Jackson, Chris;

Asteroseismology of Procyon with SOPHIE

NASA Astrophysics Data System (ADS)

Mosser, B.; Bouchy, F.; Martić, M.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Garcia, R. A.; Lebrun, J. C.; Michel, E.; Provost, J.; Thévenin, F.; Turck-Chièze, S.

2008-01-01

Context: This paper reports a 9-night asteroseismic observation program conducted in January 2007 with the new spectrometer sophie at the OHP 193-cm telescope, on the F5 IV-V target Procyon A. Aims: This first asteroseismic program with sophie was intended to test the performance of the instrument with a bright but demanding asteroseismic target and was part of a multisite network. Methods: The sophie spectra have been reduced with the data reduction software provided by OHP. The Procyon asteroseismic data were then analyzed with statistical tools. The asymptotic analysis has been conducted considering possible curvature in the échelle diagram analysis. Results: These observations have proven the efficient performance of sophie used as an asteroseismometer, and succeed in a clear detection of the large spacing. An échelle diagram based on the 54-μHz spacing shows clear ridges. Identification of the peaks exhibits large spacings varying from about 52 μHz to 56 μHz. Outside the frequency range [0.9, 1.0 mHz] where the identification is confused, the large spacing increases at a rate of about dΔν/dn ≃ 0.2 μHz. This may explain some of the different values of the large spacing obtained by previous observations. Based on observations collected with the sophie échelle spectrometer mounted on the 1.93-m telescope at OHP, France (program 06B.PNPS.BOU); http://www.obs-hp.fr/www/guide/ sophie/sophie-eng.html Table of radial velocity measurements is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/478/197

A New Large-Well 1024x1024 Si:As Detector for the Mid-Infrared

NASA Technical Reports Server (NTRS)

Mainzer, Amanda K.; Hong, John H.; Stapelbroek, M. G.; Hogue, Henry; Molyneux, Dale; Ressler, Michael E.; Watkins, Ernie; Reekstin, John; Werner, Mike; Young, Erick

2005-01-01

We present a description of a new 1024x1024 Si:As array designed for ground-based use from 5 - 28 microns. With a maximum well depth of 5e6 electrons, this device brings large-format array technology to bear on ground-based mid-infrared programs, allowing entry to the mega-pixel realm previously only accessible to the near-IR. The multiplexer design features switchable gain, a 256x256 windowing mode for extremely bright sources, and it is two-edge buttable. The device is currently in its final design phase at DRS in Cypress, CA. We anticipate completion of the foundry run in October 2005. This new array will enable wide field, high angular resolution ground-based follow up of targets found by space-based missions such as the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE).

Space Shuttle Projects

NASA Image and Video Library

1993-10-01

Designed by the mission crew members, the STS-61 crew insignia depicts the astronaut symbol superimposed against the sky with the Earth underneath. Also seen are two circles representing the optical configuration of the Hubble Space Telescope (HST). Light is focused by reflections from a large primary mirror and a smaller secondary mirror. The light is analyzed by various instruments and, according to the crew members, brings to us on Earth knowledge about planets, stars, galaxies and other celestial objects, allowing us to better understand the complex physical processes at work in the universe. The Space Shuttle Endeavour is also represented as the fundamental tool that allows the crew to perform the first servicing of the Hubble Space Telescope so its scientific deep space mission may be extended for several years to come. The overall design of the emblem, with lines converging to a high point, is also a symbolic representation of the large-scale Earth-based effort which involves space agencies, industry, and the universities to reach goals of knowledge and perfection.

Learning to reach by reinforcement learning using a receptive field based function approximation approach with continuous actions.

PubMed

Tamosiunaite, Minija; Asfour, Tamim; Wörgötter, Florentin

2009-03-01

Reinforcement learning methods can be used in robotics applications especially for specific target-oriented problems, for example the reward-based recalibration of goal directed actions. To this end still relatively large and continuous state-action spaces need to be efficiently handled. The goal of this paper is, thus, to develop a novel, rather simple method which uses reinforcement learning with function approximation in conjunction with different reward-strategies for solving such problems. For the testing of our method, we use a four degree-of-freedom reaching problem in 3D-space simulated by a two-joint robot arm system with two DOF each. Function approximation is based on 4D, overlapping kernels (receptive fields) and the state-action space contains about 10,000 of these. Different types of reward structures are being compared, for example, reward-on- touching-only against reward-on-approach. Furthermore, forbidden joint configurations are punished. A continuous action space is used. In spite of a rather large number of states and the continuous action space these reward/punishment strategies allow the system to find a good solution usually within about 20 trials. The efficiency of our method demonstrated in this test scenario suggests that it might be possible to use it on a real robot for problems where mixed rewards can be defined in situations where other types of learning might be difficult.

A Network Enabled Platform for Canadian Space Science Data

NASA Astrophysics Data System (ADS)

Rankin, R.; Boteler, D. R.; Jayachandran, T. P.; Mann, I. R.; Sofko, G.; Yau, A. W.

2008-12-01

The internet is an example of a pervasive disruptive technology that has transformed society on a global scale. The term "cyberinfrastructure" refers to technology underpinning the collaborative aspect of large science projects and is synonymous with terms such as e-Science, intelligent infrastructure, and/or e- infrastructure. In the context of space science, a significant challenge is to exploit the internet and cyberinfrastructure to form effective virtual organizations (VOs) of scientists that have common or agreed- upon objectives. A typical VO is likely to include universities and government agencies specializing in types of instrumentation (ground and/or space based), which in deployment produce large quantities of space data. Such data is most effectively described by metadata, which if defined in a standard way, facilitates discovery and retrieval of data over the internet by intelligent interfaces and cyberinfrastructure. One recent and significant approach is SPASE, which is being developed by NASA as a data-standard for its Virtual Observatories (VxOs) programs. The space science community in Canada has recently formed a VO designed to complement the e-POP microsatellite mission, and new ground-based observatories (GBOs) that collect data over a large fraction of the Canadian land-mass. The VO includes members of the CGSM community (www.cgsm.ca), which is funded operationally by the Canadian Space Agency. It also includes the UCLA VMO team, and scientists in the NASA THEMIS mission. CANARIE (www.canarie.ca), the federal agency responsible for management, design and operation of Canada's research internet, has recently recognized the value of cyberinfrastucture through the creation of a Network-Enabled-Platforms (NEPs) program. An NEP for space science was funded by CANARIE in its first competition. When fully implemented, the Space Science NEP will consist of a front-end portal providing access to CGSM data. It will utilize an adaptation of the SPASE-based registry developed by Ray Walker et. al at UCLA, along with a common set of services and federation of CGSM data. An important aspect of the space science NEP is the development of scientific workflows that allow users to more easily develop data analysis tools that can be stored on their desktop for re-use. The presentation will include a high-level view of the methodology and software architecture to be implemented through the development of the CANARIE NEP for space science.

Adaptive array antenna for satellite cellular and direct broadcast communications

NASA Technical Reports Server (NTRS)

Horton, Charles R.; Abend, Kenneth

1993-01-01

Adaptive phased-array antennas provide cost-effective implementation of large, light weight apertures with high directivity and precise beamshape control. Adaptive self-calibration allows for relaxation of all mechanical tolerances across the aperture and electrical component tolerances, providing high performance with a low-cost, lightweight array, even in the presence of large physical distortions. Beam-shape is programmable and adaptable to changes in technical and operational requirements. Adaptive digital beam-forming eliminates uplink contention by allowing a single electronically steerable antenna to service a large number of receivers with beams which adaptively focus on one source while eliminating interference from others. A large, adaptively calibrated and fully programmable aperture can also provide precise beam shape control for power-efficient direct broadcast from space. Advanced adaptive digital beamforming technologies are described for: (1) electronic compensation of aperture distortion, (2) multiple receiver adaptive space-time processing, and (3) downlink beam-shape control. Cost considerations for space-based array applications are also discussed.

Large Space Antenna Systems Technology, 1984

NASA Technical Reports Server (NTRS)

Boyer, W. J. (Compiler)

1985-01-01

Mission applications for large space antenna systems; large space antenna structural systems; materials and structures technology; structural dynamics and control technology, electromagnetics technology, large space antenna systems and the Space Station; and flight test and evaluation were examined.

Polymerisation processes in expoy resins under influence of free space environment

NASA Astrophysics Data System (ADS)

Kondyurin, A.; Lauke, B.; Kondyurina, I.

A creation of large size constructions in space or on celestial bodies is possible by the way of chemical reactions of liquid viscous components under space environment conditions [1-2]. In particular, a new technology for large-size space module for electronic components, energy and materials production is developed on the basis of polymerisation technique. The factors of free space environment have a significant influence on the polymerisation processes. The polymerisation processes in active liquid components are sensitive to microgravitation, temperature variations (-150{ldots}+1500C), high vacuum (10-3{ldots}10-7 Pa), atomic oxygen flux (on LEO), UV and VUV irradiations, X-ray and γ -irradiations, high energy electron and ion fluxes. Experiments of polymerisation processes under simulated free space conditions were conducted. The influences of high vacuum, high energy ion beam and rf- and mw-plasma on polymerisation of epoxy resins were observed. The effects of low molecular components evaporations, free radical formations, additional chemical reactions and mixing processes during polymerisation were observed. Our results showed, that the space factors can initiate the polymerisation reaction in epoxy matrix of glass and carbon fibre composites. The result can be used for a technology for large size constructions on Earth orbit, in far space and on space bodies as for deployed antennas, solar sail stringers, solar shield stringers, frame for large-size space station, frame for Moon, Mars, asteroids bases, frame for space plant on Earth orbit and on other celestial bodies. The study was partially supported by Alexander von Humboldt Foundation (A. Kondyurin) and European Space Agency, ESTEC (contract 17083/03/NL/Sfe "Space Environmental Effects on the Polymerisation of Composite Structures"). 1. A.Kondyurin, B.Lauke, Polymerisation processes in simulated free space conditions, Proceedings of the 9th International Symposium on Materials in a Space Environment, Noordwijk, The Netherlands, 16-20 June, 2003, ESA SP-540, September 2003, pp.75-80. 2. V.A.Briskman, T.M.Yudina, K.G.Kostarev, A.V.Kondyurin, V.B.Leontyev, M.G.Levkovich, A.L.Mashinsky, G.S.Nechitailo, Polymerization in microgravity as a new process in space technology, Acta Astronautica, vol.48, N2-3, 2001, pp.169-180.

Query-Based Outlier Detection in Heterogeneous Information Networks.

PubMed

Kuck, Jonathan; Zhuang, Honglei; Yan, Xifeng; Cam, Hasan; Han, Jiawei

2015-03-01

Outlier or anomaly detection in large data sets is a fundamental task in data science, with broad applications. However, in real data sets with high-dimensional space, most outliers are hidden in certain dimensional combinations and are relative to a user's search space and interest. It is often more effective to give power to users and allow them to specify outlier queries flexibly, and the system will then process such mining queries efficiently. In this study, we introduce the concept of query-based outlier in heterogeneous information networks, design a query language to facilitate users to specify such queries flexibly, define a good outlier measure in heterogeneous networks, and study how to process outlier queries efficiently in large data sets. Our experiments on real data sets show that following such a methodology, interesting outliers can be defined and uncovered flexibly and effectively in large heterogeneous networks.

Query-Based Outlier Detection in Heterogeneous Information Networks

PubMed Central

Kuck, Jonathan; Zhuang, Honglei; Yan, Xifeng; Cam, Hasan; Han, Jiawei

2015-01-01

Outlier or anomaly detection in large data sets is a fundamental task in data science, with broad applications. However, in real data sets with high-dimensional space, most outliers are hidden in certain dimensional combinations and are relative to a user’s search space and interest. It is often more effective to give power to users and allow them to specify outlier queries flexibly, and the system will then process such mining queries efficiently. In this study, we introduce the concept of query-based outlier in heterogeneous information networks, design a query language to facilitate users to specify such queries flexibly, define a good outlier measure in heterogeneous networks, and study how to process outlier queries efficiently in large data sets. Our experiments on real data sets show that following such a methodology, interesting outliers can be defined and uncovered flexibly and effectively in large heterogeneous networks. PMID:27064397

Adaptive Full Aperture Wavefront Sensor Study

NASA Technical Reports Server (NTRS)

Robinson, William G.

1997-01-01

This grant and the work described was in support of a Seven Segment Demonstrator (SSD) and review of wavefront sensing techniques proposed by the Government and Contractors for the Next Generation Space Telescope (NGST) Program. A team developed the SSD concept. For completeness, some of the information included in this report has also been included in the final report of a follow-on contract (H-27657D) entitled "Construction of Prototype Lightweight Mirrors". The original purpose of this GTRI study was to investigate how various wavefront sensing techniques might be most effectively employed with large (greater than 10 meter) aperture space based telescopes used for commercial and scientific purposes. However, due to changes in the scope of the work performed on this grant and in light of the initial studies completed for the NGST program, only a portion of this report addresses wavefront sensing techniques. The wavefront sensing techniques proposed by the Government and Contractors for the NGST were summarized in proposals and briefing materials developed by three study teams including NASA Goddard Space Flight Center, TRW, and Lockheed-Martin. In this report, GTRI reviews these approaches and makes recommendations concerning the approaches. The objectives of the SSD were to demonstrate functionality and performance of a seven segment prototype array of hexagonal mirrors and supporting electromechanical components which address design issues critical to space optics deployed in large space based telescopes for astronomy and for optics used in spaced based optical communications systems. The SSD was intended to demonstrate technologies which can support the following capabilities: Transportation in dense packaging to existing launcher payload envelopes, then deployable on orbit to form a space telescope with large aperture. Provide very large (greater than 10 meters) primary reflectors of low mass and cost. Demonstrate the capability to form a segmented primary or quaternary mirror into a quasi-continuous surface with individual subapertures phased so that near diffraction limited imaging in the visible wavelength region is achieved. Continuous compensation of optical wavefront due to perturbations caused by imperfections, natural disturbances, and equipment induced vibrations/deflections to provide near diffraction limited imaging performance in the visible wavelength region. Demonstrate the feasibility of fabricating such systems with reduced mass and cost compared to past approaches.

Second-order perturbation theory with a density matrix renormalization group self-consistent field reference function: theory and application to the study of chromium dimer.

PubMed

Kurashige, Yuki; Yanai, Takeshi

2011-09-07

We present a second-order perturbation theory based on a density matrix renormalization group self-consistent field (DMRG-SCF) reference function. The method reproduces the solution of the complete active space with second-order perturbation theory (CASPT2) when the DMRG reference function is represented by a sufficiently large number of renormalized many-body basis, thereby being named DMRG-CASPT2 method. The DMRG-SCF is able to describe non-dynamical correlation with large active space that is insurmountable to the conventional CASSCF method, while the second-order perturbation theory provides an efficient description of dynamical correlation effects. The capability of our implementation is demonstrated for an application to the potential energy curve of the chromium dimer, which is one of the most demanding multireference systems that require best electronic structure treatment for non-dynamical and dynamical correlation as well as large basis sets. The DMRG-CASPT2/cc-pwCV5Z calculations were performed with a large (3d double-shell) active space consisting of 28 orbitals. Our approach using large-size DMRG reference addressed the problems of why the dissociation energy is largely overestimated by CASPT2 with the small active space consisting of 12 orbitals (3d4s), and also is oversensitive to the choice of the zeroth-order Hamiltonian. © 2011 American Institute of Physics

Integrated analysis of large space systems

NASA Technical Reports Server (NTRS)

Young, J. P.

1980-01-01

Based on the belief that actual flight hardware development of large space systems will necessitate a formalized method of integrating the various engineering discipline analyses, an efficient highly user oriented software system capable of performing interdisciplinary design analyses with tolerable solution turnaround time is planned Specific analysis capability goals were set forth with initial emphasis given to sequential and quasi-static thermal/structural analysis and fully coupled structural/control system analysis. Subsequently, the IAC would be expanded to include a fully coupled thermal/structural/control system, electromagnetic radiation, and optical performance analyses.

Large Space Antenna Systems Technology, 1984

NASA Technical Reports Server (NTRS)

Boyer, W. J. (Compiler)

1985-01-01

Papers are presented which provide a comprehensive review of space missions requiring large antenna systems and of the status of key technologies required to enable these missions. Topic areas include mission applications for large space antenna systems, large space antenna structural systems, materials and structures technology, structural dynamics and control technology, electromagnetics technology, large space antenna systems and the space station, and flight test and evaluation.

Sensitivity of the orbiting JEM-EUSO mission to large-scale anisotropies

NASA Astrophysics Data System (ADS)

Weiler, Thomas; Anchordoqui, Luis; Denton, Peter

2013-04-01

Uniform sky coverage and very large apertures are advantages of future extreme-energy, space-based cosmic-ray observatories. In this talk we will quantify the advantage of an all-sky/4pi observatory such as JEM-EUSO over the one to two steradian coverage of a ground-based observatory such as Auger. We exploit the availability of spherical harmonics in the case of 4pi coverage. The resulting Y(lm) coefficients will likely become a standard analysis tool for near-future, space-based, cosmic-ray astronomy. We demonstrate the use of Y(lm)'s with extractions of simulated dipole and quadrupole anisotropies. (A dipole anisotropy is expected if a single source-region such as Cen A dominates the sky, while a quadrupole moment is expected if a 2D source region such as the Supergalactic Plane dominates the sky.)

ART-Ada: An Ada-based expert system tool

NASA Technical Reports Server (NTRS)

Lee, S. Daniel; Allen, Bradley P.

1990-01-01

The Department of Defense mandate to standardize on Ada as the language for software systems development has resulted in an increased interest in making expert systems technology readily available in Ada environments. NASA's Space Station Freedom is an example of the large Ada software development projects that will require expert systems in the 1990's. Another large scale application that can benefit from Ada based expert system tool technology is the Pilot's Associate (PA) expert system project for military combat aircraft. The Automated Reasoning Tool-Ada (ART-Ada), an Ada expert system tool, is explained. ART-Ada allows applications of a C-based expert system tool called ART-IM to be deployed in various Ada environments. ART-Ada is being used to implement several prototype expert systems for NASA's Space Station Freedom program and the U.S. Air Force.

ART-Ada: An Ada-based expert system tool

NASA Technical Reports Server (NTRS)

Lee, S. Daniel; Allen, Bradley P.

1991-01-01

The Department of Defense mandate to standardize on Ada as the language for software systems development has resulted in increased interest in making expert systems technology readily available in Ada environments. NASA's Space Station Freedom is an example of the large Ada software development projects that will require expert systems in the 1990's. Another large scale application that can benefit from Ada based expert system tool technology is the Pilot's Associate (PA) expert system project for military combat aircraft. Automated Reasoning Tool (ART) Ada, an Ada Expert system tool is described. ART-Ada allow applications of a C-based expert system tool called ART-IM to be deployed in various Ada environments. ART-Ada is being used to implement several prototype expert systems for NASA's Space Station Freedom Program and the U.S. Air Force.

Large engines and vehicles, 1958

NASA Technical Reports Server (NTRS)

1978-01-01

During the mid-1950s, the Air Force sponsored work on the feasibility of building large, single-chamber engines, presumably for boost-glide aircraft or spacecraft. In 1956, the Army missile development group began studies of large launch vehicles. The possibilities opened up by Sputnik accelerated this work and gave the Army an opportunity to bid for the leading role in launch vehicles. The Air Force had the responsibility for the largest ballistic missiles and hence a ready-made base for extending their capability for spaceflight. During 1958, actions taken to establish a civilian space agency, and the launch vehicle needs seen by its planners, added a third contender to the space vehicle competition. These activities during 1958 are examined as to how they resulted in the initiation of a large rocket engine and the first large launch vehicle.

Space- and time-resolved raman and breakdown spectroscopy: advanced lidar techniques

NASA Astrophysics Data System (ADS)

Silviu, Gurlui; Marius Mihai, Cazacu; Adrian, Timofte; Oana, Rusu; Georgiana, Bulai; Dimitriu, Dan

2018-04-01

DARLIOES - the advanced LIDAR is based on space- and time-resolved RAMAN and breakdown spectroscopy, to investigate chemical and toxic compounds, their kinetics and physical properties at high temporal (2 ns) and spatial (1 cm) resolution. The high spatial and temporal resolution are needed to resolve a large variety of chemical troposphere compounds, emissions from aircraft, the self-organization space charges induced light phenomena, temperature and humidity profiles, ice nucleation, etc.

FARMS: The Flexible Agricultural Robotics Manipulator

NASA Technical Reports Server (NTRS)

Gill, Paul S.

1991-01-01

A technology utilization project was established with the Marshall Space Flight Center and the University of Georgia to develop an Earth-based, robotic end effector to process live plant (geranium) material which will improve productivity and efficiency in agricultural systems such as commercial nurseries and greenhouse systems. The aim is to apply this technology to NASA's presence in space, including permanently manned space stations and manned planetary communities requiring large scale food production needs.

Space station systems analysis study. Part 3: Documentation. Volume 7: SCB alternate EPS evaluation, task 10

NASA Technical Reports Server (NTRS)

1977-01-01

Power levels up to 100 kWe average were baselined for the electrical power system of the space construction base, a long-duration manned facility capable of supporting manufacturing and large scale construction projects in space. Alternatives to the solar array battery systems discussed include: (1) solar concentrator/brayton; (2) solar concentrator/thermionic; (3) isotope/brayton; (4) nuclear/brayton; (5) nuclear thermoelectric; and (6) nuclear thermionic.

Space Spider - A concept for fabrication of large structures

NASA Technical Reports Server (NTRS)

Britton, W. R.; Johnston, J. D.

1978-01-01

The Space Spider concept for the automated fabrication of large space structures involves a specialized machine which roll-forms thin gauge material such as aluminum and develops continuous spiral structures with radial struts to sizes of 600-1,000 feet in diameter by 15 feet deep. This concept allows the machine and raw material to be integrated using the Orbiter capabilities, then boosting the rigid system to geosynchronous equatorial orbit (GEO) without high sensitivity to acceleration forces. As a teleoperator controlled device having repetitive operations, the fabrication process can be monitored and verified from a ground-based station without astronaut involvement in GEO. The resultant structure will be useful as an intermediate size platform or as a structural element to be used with other elements such as the space-fabricated beams or composite nested tubes.

Imaging the Surfaces of Stars from Space

NASA Astrophysics Data System (ADS)

Carpenter, Kenneth; Rau, Gioia

2018-04-01

Imaging of Stellar Surfacess has been dominated to-date by ground-based observations, but space-based facilities offer tremendous potential for extending the wavelength coverage and ultimately the resolution of such efforts. We review the imaging accomplished so far from space and then talk about exciting future prospects. The earliest attempts from space indirectly produced surface maps via the Doppler Imaging Technique, using UV spectra obtained with the International Ultraviolet Explorer (IUE). Later, the first direct UV images were obtained with the Hubble Space Telescope (HST), of Mira and Betelgeuse, using the Faint Object Camera (FOC). We will show this work and then investigate prospects for IR imaging with the James Webb Space Telescope (JWST). The real potential of space-based Imaging of Stellar Surfacess, however, lies in the future, when large-baseline Fizeau interferometers, such as the UV-optical Stellar Imager (SI) Vision Mission, with a 30-element array and 500m max baseline, are flown. We describe SI and its science goals, which include 0.1 milli-arcsec spectral Imaging of Stellar Surfacess and the probing of internal structure and flows via asteroseismology.

Image degradation characteristics and restoration based on regularization for diffractive imaging

NASA Astrophysics Data System (ADS)

Zhi, Xiyang; Jiang, Shikai; Zhang, Wei; Wang, Dawei; Li, Yun

2017-11-01

The diffractive membrane optical imaging system is an important development trend of ultra large aperture and lightweight space camera. However, related investigations on physics-based diffractive imaging degradation characteristics and corresponding image restoration methods are less studied. In this paper, the model of image quality degradation for the diffraction imaging system is first deduced mathematically based on diffraction theory and then the degradation characteristics are analyzed. On this basis, a novel regularization model of image restoration that contains multiple prior constraints is established. After that, the solving approach of the equation with the multi-norm coexistence and multi-regularization parameters (prior's parameters) is presented. Subsequently, the space-variant PSF image restoration method for large aperture diffractive imaging system is proposed combined with block idea of isoplanatic region. Experimentally, the proposed algorithm demonstrates its capacity to achieve multi-objective improvement including MTF enhancing, dispersion correcting, noise and artifact suppressing as well as image's detail preserving, and produce satisfactory visual quality. This can provide scientific basis for applications and possesses potential application prospects on future space applications of diffractive membrane imaging technology.

Earth-Space Propagation Data Bases

NASA Technical Reports Server (NTRS)

Smith, Ernest K.

1996-01-01

This paper, designed for the newcomer rather than the expert, will take a rather broad view of what is meant by 'propagation data bases' in that it will take the term to mean both the actual measurements and models of Earth-space paths. The text will largely be drawn from International Radio Consultative Committee (CCIR) reports, now annexed to the Recommendations of the International Telecommunications Union-R Study Group 3, plus some experience with a course taught at the University of Colorado.

Space shuttle main engine anomaly data and inductive knowledge based systems: Automated corporate expertise

NASA Technical Reports Server (NTRS)

Modesitt, Kenneth L.

1987-01-01

Progress is reported on the development of SCOTTY, an expert knowledge-based system to automate the analysis procedure following test firings of the Space Shuttle Main Engine (SSME). The integration of a large-scale relational data base system, a computer graphics interface for experts and end-user engineers, potential extension of the system to flight engines, application of the system for training of newly-hired engineers, technology transfer to other engines, and the essential qualities of good software engineering practices for building expert knowledge-based systems are among the topics discussed.

THE SAN PEDRO RIVER SPATIAL DATA ARCHIVE, A DATABASE BROWSER FOR COMMUNITY-BASED ENVIRONMENTAL PROTECTION

EPA Science Inventory

It is currently possible to measure landscape change over large areas and determine trends in ecological and hydrological condition using advanced space-based technologies accompanied by geospatial data. Specifically, this process is being tested in a community-based watershed in...

THE SAN PEDRO SPATIAL DATA ARCHIVE, A DATABASE BROWSER FOR COMMUNITY-BASED ENVIRONMENTAL PROTECTION

EPA Science Inventory

It is currently possible to measure landscape change over large areas and determine trends in ecological and hydrological condition using advanced space-based technologies accompanied by geospatial data. Specifically, this process is being tested in a community-based watershed in...

Spectral decomposition of asteroid Itokawa based on principal component analysis

NASA Astrophysics Data System (ADS)

Koga, Sumire C.; Sugita, Seiji; Kamata, Shunichi; Ishiguro, Masateru; Hiroi, Takahiro; Tatsumi, Eri; Sasaki, Sho

2018-01-01

The heliocentric stratification of asteroid spectral types may hold important information on the early evolution of the Solar System. Asteroid spectral taxonomy is based largely on principal component analysis. However, how the surface properties of asteroids, such as the composition and age, are projected in the principal-component (PC) space is not understood well. We decompose multi-band disk-resolved visible spectra of the Itokawa surface with principal component analysis (PCA) in comparison with main-belt asteroids. The obtained distribution of Itokawa spectra projected in the PC space of main-belt asteroids follows a linear trend linking the Q-type and S-type regions and is consistent with the results of space-weathering experiments on ordinary chondrites and olivine, suggesting that this trend may be a space-weathering-induced spectral evolution track for S-type asteroids. Comparison with space-weathering experiments also yield a short average surface age (< a few million years) for Itokawa, consistent with the cosmic-ray-exposure time of returned samples from Itokawa. The Itokawa PC score distribution exhibits asymmetry along the evolution track, strongly suggesting that space weathering has begun saturated on this young asteroid. The freshest spectrum found on Itokawa exhibits a clear sign for space weathering, indicating again that space weathering occurs very rapidly on this body. We also conducted PCA on Itokawa spectra alone and compared the results with space-weathering experiments. The obtained results indicate that the first principal component of Itokawa surface spectra is consistent with spectral change due to space weathering and that the spatial variation in the degree of space weathering is very large (a factor of three in surface age), which would strongly suggest the presence of strong regional/local resurfacing process(es) on this small asteroid.

Space-Time Controls on Carbon Sequestration Over Large-Scale Amazon Basin

NASA Technical Reports Server (NTRS)

Smith, Eric A.; Cooper, Harry J.; Gu, Jiujing; Grose, Andrew; Norman, John; daRocha, Humberto R.; Starr, David O. (Technical Monitor)

2002-01-01

A major research focus of the LBA Ecology Program is an assessment of the carbon budget and the carbon sequestering capacity of the large scale forest-pasture system that dominates the Amazonia landscape, and its time-space heterogeneity manifest in carbon fluxes across the large scale Amazon basin ecosystem. Quantification of these processes requires a combination of in situ measurements, remotely sensed measurements from space, and a realistically forced hydrometeorological model coupled to a carbon assimilation model, capable of simulating details within the surface energy and water budgets along with the principle modes of photosynthesis and respiration. Here we describe the results of an investigation concerning the space-time controls of carbon sources and sinks distributed over the large scale Amazon basin. The results are derived from a carbon-water-energy budget retrieval system for the large scale Amazon basin, which uses a coupled carbon assimilation-hydrometeorological model as an integrating system, forced by both in situ meteorological measurements and remotely sensed radiation fluxes and precipitation retrieval retrieved from a combination of GOES, SSM/I, TOMS, and TRMM satellite measurements. Brief discussion concerning validation of (a) retrieved surface radiation fluxes and precipitation based on 30-min averaged surface measurements taken at Ji-Parana in Rondonia and Manaus in Amazonas, and (b) modeled carbon fluxes based on tower CO2 flux measurements taken at Reserva Jaru, Manaus and Fazenda Nossa Senhora. The space-time controls on carbon sequestration are partitioned into sets of factors classified by: (1) above canopy meteorology, (2) incoming surface radiation, (3) precipitation interception, and (4) indigenous stomatal processes varied over the different land covers of pristine rainforest, partially, and fully logged rainforests, and pasture lands. These are the principle meteorological, thermodynamical, hydrological, and biophysical control paths which perturb net carbon fluxes and sequestration, produce time-space switching of carbon sources and sinks, undergo modulation through atmospheric boundary layer feedbacks, and respond to any discontinuous intervention on the landscape itself such as produced by human intervention in converting rainforest to pasture or conducting selective/clearcut logging operations.

Shaping up nucleic acid computation.

PubMed

Chen, Xi; Ellington, Andrew D

2010-08-01

Nucleic acid-based nanotechnology has always been perceived as novel, but has begun to move from theoretical demonstrations to practical applications. In particular, the large address spaces available to nucleic acids can be exploited to encode algorithms and/or act as circuits and thereby process molecular information. In this review we not only revisit several milestones in the field of nucleic acid-based computation, but also highlight how the prospects for nucleic acid computation go beyond just a large address space. Functional nucleic acid elements (aptamers, ribozymes, and deoxyribozymes) can serve as inputs and outputs to the environment, and can act as logical elements. Into the future, the chemical dynamics of nucleic acids may prove as useful as hybridization for computation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Actuated Hybrid Mirrors for Space Telescopes

NASA Technical Reports Server (NTRS)

Hickey, Gregory; Ealey, Mark; Redding, David

2010-01-01

This paper describes new, large, ultra-lightweight, replicated, actively controlled mirrors, for use in space telescopes. These mirrors utilize SiC substrates, with embedded solid-state actuators, bonded to Nanolaminate metal foil reflective surfaces. Called Actuated Hybrid Mirrors (AHMs), they use replication techniques for high optical quality as well as rapid, low cost manufacturing. They enable an Active Optics space telescope architecture that uses periodic image-based wavefront sensing and control to assure diffraction-limited performance, while relaxing optical system fabrication, integration and test requirements. The proposed International Space Station Observatory seeks to demonstrate this architecture in space.

Automation and Robotics for Space-Based Systems, 1991

NASA Technical Reports Server (NTRS)

Williams, Robert L., II (Editor)

1992-01-01

The purpose of this in-house workshop was to assess the state-of-the-art of automation and robotics for space operations from an LaRC perspective and to identify areas of opportunity for future research. Over half of the presentations came from the Automation Technology Branch, covering telerobotic control, extravehicular activity (EVA) and intra-vehicular activity (IVA) robotics, hand controllers for teleoperation, sensors, neural networks, and automated structural assembly, all applied to space missions. Other talks covered the Remote Manipulator System (RMS) active damping augmentation, space crane work, modeling, simulation, and control of large, flexible space manipulators, and virtual passive controller designs for space robots.

Cloudy with a Chance of Solar Flares: The Sun as a Natural Hazard

NASA Technical Reports Server (NTRS)

Pellish, Jonathan

2017-01-01

Space weather is a naturally occurring phenomenon that represents a quantifiable risk to space- and ground-based infrastructure as well as society at large. Space weather hazards include permanent and correctable faults in computer systems, Global Positioning System (GPS) and high-frequency communication disturbances, increased airline passenger and astronaut radiation exposure, and electric grid disruption. From the National Space Weather Strategy, published by the Office of Science and Technology Policy in October 2015, space weather refers to the dynamic conditions of the space environment that arise from emissions from the Sun, which include solar flares, solar energetic particles, and coronal mass ejections. These emissions can interact with Earth and its surrounding space, including the Earth's magnetic field, potentially disrupting technologies and infrastructures. Space weather is measured using a range of space- and ground-based platforms that directly monitor the Sun, the Earth's magnetic field, the conditions in interplanetary space and impacts at Earth's surface, like neutron ground-level enhancement. The NASA Goddard Space Flight Center's Space Weather Research Center and their international collaborators in government, industry, and academia are working towards improved techniques for predicting space weather as part of the strategy and action plan to better quantify and mitigate space weather hazards. In addition to accurately measuring and predicting space weather, we also need to continue developing more advanced techniques for evaluating space weather impacts on space- and ground-based infrastructure. Within the Earth's atmosphere, elevated neutron flux driven by atmosphere-particle interactions from space weather is a primary risk source. Ground-based neutron sources form an essential foundation for quantifying space weather impacts in a variety of systems.

Fault Tolerant Frequent Pattern Mining

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

Shohdy, Sameh; Vishnu, Abhinav; Agrawal, Gagan

FP-Growth algorithm is a Frequent Pattern Mining (FPM) algorithm that has been extensively used to study correlations and patterns in large scale datasets. While several researchers have designed distributed memory FP-Growth algorithms, it is pivotal to consider fault tolerant FP-Growth, which can address the increasing fault rates in large scale systems. In this work, we propose a novel parallel, algorithm-level fault-tolerant FP-Growth algorithm. We leverage algorithmic properties and MPI advanced features to guarantee an O(1) space complexity, achieved by using the dataset memory space itself for checkpointing. We also propose a recovery algorithm that can use in-memory and disk-based checkpointing,more » though in many cases the recovery can be completed without any disk access, and incurring no memory overhead for checkpointing. We evaluate our FT algorithm on a large scale InfiniBand cluster with several large datasets using up to 2K cores. Our evaluation demonstrates excellent efficiency for checkpointing and recovery in comparison to the disk-based approach. We have also observed 20x average speed-up in comparison to Spark, establishing that a well designed algorithm can easily outperform a solution based on a general fault-tolerant programming model.« less

Hurdles to Overcome to Model Carrington Class Events

NASA Astrophysics Data System (ADS)

Engel, M.; Henderson, M. G.; Jordanova, V. K.; Morley, S.

2017-12-01

Large geomagnetic storms pose a threat to both space and ground based infrastructure. In order to help mitigate that threat a better understanding of the specifics of these storms is required. Various computer models are being used around the world to analyze the magnetospheric environment, however they are largely inadequate for analyzing the large and extreme storm time environments. Here we report on the first steps towards expanding and robustifying the RAM-SCB inner magnetospheric model, used in conjunction with BATS-R-US and the Space Weather Modeling Framework, in order to simulate storms with Dst > -400. These results will then be used to help expand our modelling capabilities towards including Carrington-class events.

Space qualification of silicon carbide for mirror applications: progress and future objectives

NASA Astrophysics Data System (ADS)

Palusinski, Iwona A.; Ghozeil, Isaac

2006-09-01

Production of optical silicon carbide (SiC) for mirror applications continues to evolve and there are renewed plans to use this material in future space-based systems. While SiC has the potential for rapid and cost-effective manufacturing of large, lightweight, athermal optical systems, this material's use in mirror applications is relatively new and has limited flight heritage. This combination of drivers stresses the necessity for a space qualification program for this material. Successful space qualification will require independent collaboration to absorb the high cost of executing this program while taking advantage of each contributing group's laboratory expertise to develop a comprehensive SiC database. This paper provides an overview of the trends and progress in the production of SiC, and identifies future objectives such as non-destructive evaluation and space-effects modeling to ensure proper implementation of this material into future space-based systems.

14 CFR Section 04 - Air Carrier Groupings

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Air Carrier Groupings Section 04 Section 04... REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Section 04 Air Carrier Groupings (a) All large certificated air carriers are placed into three basic air carrier groupings based...

14 CFR Section 04 - Air Carrier Groupings

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Air Carrier Groupings Section 04 Section 04... REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Section 04 Air Carrier Groupings (a) All large certificated air carriers are placed into three basic air carrier groupings based...

14 CFR Section 04 - Air Carrier Groupings

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Air Carrier Groupings Section 04 Section 04... REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Section 04 Air Carrier Groupings (a) All large certificated air carriers are placed into three basic air carrier groupings based...

14 CFR Section 04 - Air Carrier Groupings

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Air Carrier Groupings Section 04 Section 04... REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Section 04 Air Carrier Groupings (a) All large certificated air carriers are placed into three basic air carrier groupings based...

META II: Formal Co-Verification of Correctness of Large-Scale Cyber-Physical Systems during Design. Volume 1

DTIC Science & Technology

2011-08-01

design space is large. His research contributions are to the field of Decision-based Design, specifically in linking consumer preferences and...Integrating Consumer Preferences into Engineering Design, to be published in 2012. He received his PhD from Northwestern University in Mechanical

CESIC: a new technology for lightweight and cost effective space instrument structures and mirrors

NASA Astrophysics Data System (ADS)

Devilliers, Christophe; Kroedel, Matthias R.

2005-08-01

For some years Alcatel Space has been interested in the development of a new material to produce lightweight, stiff, stable and cost effective structures and mirrors for space instrument. Cesic from ECM has been selected for its intrinsic properties (high specific modulus, high conductivity, quite low thermal expansion coefficient and high fracture toughness for a ceramic material), added to ample manufacturing capabilities. Under ESA responsibility, a flight representative optical bench of Cesic has been designed, manufactured and tested. The optical bench has been submitted with success to intensive vibration tests up to 80 g on shaker without problem and was tested down to 30 K showing very high stability. Cesic is also envisaged for large and lightweight space telescope mirrors. Coatings on the Cesic substrate have been developed and qualified for the most stringent optical needs. To prove the lightweight capability, a large Cesic mirror D=950 mm with an area mass of less than 25 kg/m2 has been designed, sized again launch loads and WFE performance, and then manufactured. Cesic is also envisaged for large future focal plane holding a large number of detectors assuring high stability thanks to its high thermal conductivity. A full size Cesic focal plane has been already successfully built and tested. Based on these successful results, Alcatel Space is now in position to propose for space projects this technology mastered in common with ECM both for mirrors and structures with new innovative concepts thanks to the manufacturing capabilities of this technology.

Between heaven and earth: The legal challenges of human space travel

NASA Astrophysics Data System (ADS)

Masson-Zwaan, Tanja; Freeland, Steven

2010-06-01

Since the first space object was launched into orbit in 1957, humankind has been engaged in a constant effort to realise ever more ambitious plans for space travel. Probably the single most important element in this ongoing evolution is the development of technology capable of transporting large numbers of passengers into outer space on a commercial basis. Within the foreseeable future, space will no longer be the sole domain of professionally trained astronauts or the exceptionally wealthy. The prospects for both suborbital and orbital private human access to space give rise to some interesting and difficult legal questions. It also opens up an exciting opportunity to develop an adequate system of legal regulation to deal with these activities. The existing international legal regimes covering air and space activities are not well suited to large-scale commercial access to space, largely because they were developed at a time when such activities were not a principal consideration in the mind of the drafters. The lack of legal clarity represents a major challenge and must be addressed as soon as possible, to provide for appropriate standards and further encourage (not discourage) such activities. This article will examine some of the more pressing legal issues associated with the regulation of space transportation of passengers on a commercial basis, seen in the light of Article 1 of the Outer Space Treaty of 1967, which states that the 'exploration and use of outer space […] shall be carried out for the benefit and in the interests of all countries […] and shall be the province of all mankind'. An appropriate balance must be found between the commercial and technological opportunities that will arise and the principles upon which the development of international space law have thus far been based.

Propagative selection of tilted array patterns in directional solidification

NASA Astrophysics Data System (ADS)

Song, Younggil; Akamatsu, Silvère; Bottin-Rousseau, Sabine; Karma, Alain

2018-05-01

We investigate the dynamics of tilted cellular/dendritic array patterns that form during directional solidification of a binary alloy when a preferred-growth crystal axis is misoriented with respect to the temperature gradient. In situ experimental observations and phase-field simulations in thin samples reveal the existence of a propagative source-sink mechanism of array spacing selection that operates on larger space and time scales than the competitive growth at play during the initial solidification transient. For tilted arrays, tertiary branching at the diverging edge of the sample acts as a source of new cells with a spacing that can be significantly larger than the initial average spacing. A spatial domain of large spacing then invades the sample propagatively. It thus yields a uniform spacing everywhere, selected independently of the initial conditions, except in a small region near the converging edge of the sample, which acts as a sink of cells. We propose a discrete geometrical model that describes the large-scale evolution of the spatial spacing profile based on the local dependence of the cell drift velocity on the spacing. We also derive a nonlinear advection equation that predicts the invasion velocity of the large-spacing domain, and sheds light on the fundamental nature of this process. The models also account for more complex spacing modulations produced by an irregular dynamics at the source, in good quantitative agreement with both phase-field simulations and experiments. This basic knowledge provides a theoretical basis to improve the processing of single crystals or textured polycrystals for advanced materials.

Microlens Masses from Astrometry and Parallax in Space-based Surveys: From Planets to Black Holes

NASA Astrophysics Data System (ADS)

Gould, Andrew; Yee, Jennifer C.

2014-03-01

We show that space-based microlensing experiments can recover lens masses and distances for a large fraction of all events (those with individual photometric errors <~ 0.01 mag) using a combination of one-dimensional microlens parallaxes and astrometric microlensing. This will provide a powerful probe of the mass distributions of planets, black holes, and neutron stars, the distribution of planets as a function of Galactic environment, and the velocity distributions of black holes and neutron stars. While systematics are in principle a significant concern, we show that it is possible to vet against all systematics (known and unknown) using single-epoch precursor observations with the Hubble Space Telescope roughly 10 years before the space mission.

Space industrialization - Education. [via communication satellites

NASA Technical Reports Server (NTRS)

Joels, K. M.

1978-01-01

The components of an educational system based on, and perhaps enhanced by, space industrialization communications technology are considered. Satellite technology has introduced a synoptic distribution system for various transmittable educational media. The cost of communications satellite distribution for educational programming has been high. It has, therefore, been proposed to utilize Space Shuttle related technology and Large Space Structures (LSS) to construct a system with a quantum advancement in communication capability and a quantum reduction in user cost. LSS for communications purposes have three basic advantages for both developed and emerging nations, including the ability to distribute signals over wide geographic areas, the reduced cost of satellite communications systems versus installation of land based systems, and the ability of a communication satellite system to create instant educational networks.

Construction of Prototype Lightweight Mirrors

NASA Technical Reports Server (NTRS)

Robinson, William G.

1997-01-01

This contract and the work described was in support of a Seven Segment Demonstrator (SSD) and demonstration of a different technology for construction of lightweight mirrors. The objectives of the SSD were to demonstrate functionality and performance of a seven segment prototype array of hexagonal mirrors and supporting electromechanical components which address design issues critical to space optics deployed in large space based telescopes for astronomy and for optics used in spaced based optical communications systems. The SSD was intended to demonstrate technologies which can support the following capabilities; Transportation in dense packaging to existing launcher payload envelopes, then deployable on orbit to form space telescope with large aperture. Provide very large (less than 10 meters) primary reflectors of low mass and cost. Demonstrate the capability to form a segmented primary or quaternary mirror into a quasi-continuous surface with individual subapertures phased so that near diffraction limited imaging in the visible wavelength region is achieved. Continuous compensation of optical wavefront due to perturbations caused by imperfections, natural disturbances, and equipment induced vibrations/deflections to provide near diffraction limited imaging performance in the visible wavelength region. Demonstrate the feasibility of fabricating such systems with reduced mass and cost compared to past approaches. While the SSD could not be expected to satisfy all of the above capabilities, the intent was to start identifying and understanding new technologies that might be applicable to these goals.

ClustENM: ENM-Based Sampling of Essential Conformational Space at Full Atomic Resolution

PubMed Central

Kurkcuoglu, Zeynep; Bahar, Ivet; Doruker, Pemra

2016-01-01

Accurate sampling of conformational space and, in particular, the transitions between functional substates has been a challenge in molecular dynamic (MD) simulations of large biomolecular systems. We developed an Elastic Network Model (ENM)-based computational method, ClustENM, for sampling large conformational changes of biomolecules with various sizes and oligomerization states. ClustENM is an iterative method that combines ENM with energy minimization and clustering steps. It is an unbiased technique, which requires only an initial structure as input, and no information about the target conformation. To test the performance of ClustENM, we applied it to six biomolecular systems: adenylate kinase (AK), calmodulin, p38 MAP kinase, HIV-1 reverse transcriptase (RT), triosephosphate isomerase (TIM), and the 70S ribosomal complex. The generated ensembles of conformers determined at atomic resolution show good agreement with experimental data (979 structures resolved by X-ray and/or NMR) and encompass the subspaces covered in independent MD simulations for TIM, p38, and RT. ClustENM emerges as a computationally efficient tool for characterizing the conformational space of large systems at atomic detail, in addition to generating a representative ensemble of conformers that can be advantageously used in simulating substrate/ligand-binding events. PMID:27494296

Space Construction Automated Fabrication Experiment Definition Study (SCAFEDS). Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1978-01-01

The techniques, processes, and equipment required for automatic fabrication and assembly of structural elements in space using the space shuttle as a launch vehicle and construction base were investigated. Additional construction/systems/operational techniques, processes, and equipment which can be developed/demonstrated in the same program to provide further risk reduction benefits to future large space systems were included. Results in the areas of structure/materials, fabrication systems (beam builder, assembly jig, and avionics/controls), mission integration, and programmatics are summarized. Conclusions and recommendations are given.

Tunable multiwavelength SOA fiber laser with ultra-narrow wavelength spacing based on nonlinear polarization rotation.

PubMed

Zhang, Zuxing; Wu, Jian; Xu, Kun; Hong, Xiaobin; Lin, Jintong

2009-09-14

A tunable multiwavelength fiber laser with ultra-narrow wavelength spacing and large wavelength number using a semiconductor optical amplifier (SOA) has been demonstrated. Intensity-dependent transmission induced by nonlinear polarization rotation in the SOA accounts for stable multiwavelength operation with wavelength spacing less than the homogenous broadening linewidth of the SOA. Stable multiwavelength lasing with wavelength spacing as small as 0.08 nm and wavelength number up to 126 is achieved at room temperature. Moreover, wavelength tuning of 20.2 nm is implemented via polarization tuning.

Land water storage from space and the geodetic infrastructure

NASA Astrophysics Data System (ADS)

Cazenave, A.; Larson, K.; Wahr, J.

2009-04-01

In recent years, remote sensing techniques have been increasingly used to monitor components of the water balance of large river basins. By complementing scarce in situ observations and hydrological modelling, space observations have the potential to significantly improve our understanding of hydrological processes at work in river basins and their relationship with climate variability and socio-economic life. Among the remote sensing tools used in land hydrology, several originate from space geodesy and are integral parts of the Global Geodetic Observing System. For example, satellite altimetry is used for systematic monitoring of water levels of large rivers, lakes and floodplains. InSAR allows the detection of surface water change. GRACE-based space gravity offers for the first time the possibility of directly measuring the spatio-temporal variations of the vertically integrated water storage in large river basins. GRACE is also extremely useful for measuring changes in mass of the snow pack in boreal regions. Vertical motions of the ground induced by changes in water storage in aquifers can be measured by both GPS and InSAR. These techniques can also be used to investigate water loading effects. Recently GPS has been used to measure changes in surface soil moisture, which would be important for agriculture, weather prediction, and for calibrationg satellite missions such as SMOS and SMAP. These few examples show that space and ground geodetic infrastructures are increasingly important for hydrological sciences and applications. Future missions like SWOT (Surface Waters Ocean Topography; a wide swath interferometric altimetry mission) and GRACE 2 (space gravimetry mission based on new technology) will provide a new generation of hydrological products with improved precision and resolution.

Collaboration Between NASA Centers of Excellence on Autonomous System Software Development

NASA Technical Reports Server (NTRS)

Goodrich, Charles H.; Larson, William E.; Delgado, H. (Technical Monitor)

2001-01-01

Software for space systems flight operations has its roots in the early days of the space program when computer systems were incapable of supporting highly complex and flexible control logic. Control systems relied on fast data acquisition and supervisory control from a roomful of systems engineers on the ground. Even though computer hardware and software has become many orders of magnitude more capable, space systems have largely adhered to this original paradigm In an effort to break this mold, Kennedy Space Center (KSC) has invested in the development of model-based diagnosis and control applications for ten years having broad experience in both ground and spacecraft systems and software. KSC has now partnered with Ames Research Center (ARC), NASA's Center of Excellence in Information Technology, to create a new paradigm for the control of dynamic space systems. ARC has developed model-based diagnosis and intelligent planning software that enables spacecraft to handle most routine problems automatically and allocate resources in a flexible way to realize mission objectives. ARC demonstrated the utility of onboard diagnosis and planning with an experiment aboard Deep Space I in 1999. This paper highlights the software control system collaboration between KSC and ARC. KSC has developed a Mars In-situ Resource Utilization testbed based on the Reverse Water Gas Shift (RWGS) reaction. This plant, built in KSC's Applied Chemistry Laboratory, is capable of producing the large amount of Oxygen that would be needed to support a Human Mars Mission. KSC and ARC are cooperating to develop an autonomous, fault-tolerant control system for RWGS to meet the need for autonomy on deep space missions. The paper will also describe how the new system software paradigm will be applied to Vehicle Health Monitoring, tested on the new X vehicles and integrated into future launch processing systems.

Workplace Lactation Support in Milwaukee County 5 Years After the Affordable Care Act.

PubMed

Lennon, Tyler; Willis, Earnestine

2017-02-01

Workplace lactation support has become increasingly important because returning to work is associated with discontinuing breastfeeding and women in the workforce are increasing. Research aim: This study examined workplace lactation support among Milwaukee County businesses 5 years after implementation of the Affordable Care Act's Break Time for Nursing Mothers provision. A cross-sectional survey of Milwaukee County businesses was conducted in the summer of 2015 that inquired about workplace policies, lactation spaces, and other lactation resources offered. Business supports were stratified based on employer sizes: large (> 500 employees), medium (50-499 employees), and small (20-49 employees). A lactation amenity score was calculated for each business based on lactation resources available. Three hundred surveys were distributed and 71 businesses voluntarily completed the survey. Small employers were excluded from statistical analysis due to fewer responses ( n = 8). Overall, 87.3% ( n = 55) of respondents reported providing access to a multiuser space for lactation and 65.1% ( n = 41) reported providing a designated lactation space. Large employers ( n = 30) were more likely than medium employers ( n = 33) to provide a designated lactation space for breastfeeding or expressing (86.7% vs. 45.5%, p < .001). Large employers' mean amenity score was significantly higher than that of medium employers (3.37 vs. 2.57, p = .014), and they were also more likely to offer additional supports including access to a lactation consultant, classes, and materials (46.7% vs. 12.1%, p < .01). Large employers provide more lactation support than medium employers in Milwaukee County. All employers, regardless of size, need to increase additional lactation support for women in the workplace.

Innovative Approaches to Space-Based Manufacturing and Rapid Prototyping of Composite Materials

NASA Technical Reports Server (NTRS)

Hill, Charles S.

2012-01-01

The ability to deploy large habitable structures, construct, and service exploration vehicles in low earth orbit will be an enabling capability for continued human exploration of the solar system. It is evident that advanced manufacturing methods to fabricate replacement parts and re-utilize launch vehicle structural mass by converting it to different uses will be necessary to minimize costs and allow flexibility to remote crews engaged in space travel. Recent conceptual developments and the combination of inter-related approaches to low-cost manufacturing of composite materials and structures are described in context leading to the possibility of on-orbit and space-based manufacturing.

Millimeterwave Space Power Grid architecture development 2012

NASA Astrophysics Data System (ADS)

Komerath, Narayanan; Dessanti, Brendan; Shah, Shaan

This is an update of the Space Power Grid architecture for space-based solar power with an improved design of the collector/converter link, the primary heater and the radiator of the active thermal control system. The Space Power Grid offers an evolutionary approach towards TeraWatt-level Space-based solar power. The use of millimeter wave frequencies (around 220GHz) and Low-Mid Earth Orbits shrinks the size of the space and ground infrastructure to manageable levels. In prior work we showed that using Brayton cycle conversion of solar power allows large economies of scale compared to the linear mass-power relationship of photovoltaic conversion. With high-temperature materials permitting 3600 K temperature in the primary heater, over 80 percent cycle efficiency was shown with a closed helium cycle for the 1GW converter satellite which formed the core element of the architecture. Work done since the last IEEE conference has shown that the use of waveguides incorporated into lighter-than-air antenna platforms, can overcome the difficulties in transmitting millimeter wave power through the moist, dense lower atmosphere. A graphene-based radiator design conservatively meets the mass budget for the waste heat rejection system needed for the compressor inlet temperature. Placing the ultralight Mirasol collectors in lower orbits overcomes the solar beam spot size problem of high-orbit collection. The architecture begins by establishing a power exchange with terrestrial renewable energy plants, creating an early revenue generation approach with low investment. The approach allows for technology development and demonstration of high power millimeter wave technology. A multinational experiment using the International Space Station and another power exchange satellite is proposed to gather required data and experience, thus reducing the technical and policy risks. The full-scale architecture deploys pairs of Mirasol sunlight collectors and Girasol 1 GW converter satellites t- ramp up space solar power level to over 5.6 TeraWatts by year 50 from project start. Runway-based launch and landing are required to achieve the launch productivity as well as the cost reductions to enable such a large deployment on schedule. Advancements in the certainty of millimeter wave conversion technology and runway-based space access, are seen to be the outstanding issues in proceeding to full-scale Space Solar Power.

Benefits of Microalgae for Human Space Exploration

NASA Technical Reports Server (NTRS)

Verrecchia, Angelique; Bebout, Brad M.; Murphy, Thomas

2015-01-01

Algae have long been known to offer a number of benefits to support long duration human space exploration. Algae contain proteins, essential amino acids, vitamins, and lipids needed for human consumption, and can be produced using waste streams, while consuming carbon dioxide, and producing oxygen. In comparison with higher plants, algae have higher growth rates, fewer environmental requirements, produce far less "waste" tissue, and are resistant to digestion and/or biodegradation. As an additional benefit, algae produce many components (fatty acids, H2, etc.) which are useful as biofuels. On Earth, micro-algae survive in many harsh environments including low humidity, extremes in temperature, pH, and as well as high salinity and solar radiation. Algae have been shown to survive inmicro-gravity, and can adapt to high and low light intensity while retaining their ability to perform nitrogen fixation and photosynthesis. Studies have demonstrated that some algae are resistant to the space radiation environment, including solar ultraviolet radiation. It remains to be experimentally demonstrated, however, that an algal-based system could fulfil the requirements for a space-based Bioregenerative Life Support System (BLSS) under comparable spaceflight power, mass, and environmental constraints. Two specific challenges facing algae cultivation in space are that (i) conventional growth platforms require large masses of water, which in turn require a large amount of propulsion fuel, and (ii) most nutrient delivery mechanisms (predominantly bubbling) are dependent on gravity. To address these challenges, we have constructed a low water biofilm based bioreactor whose operation is enabled by capillary forces. Preliminary characterization of this Surface Adhering BioReactor (SABR) suggests that it can serve as a platform for cultivating algae in space which requires about 10 times less mass than conventional reactors without sacrificing growth rate. Further work is necessary to compare the performance of microalgae-based systems, including SABR, with systems based on higher plants, as well as conventional physicochemical-based systems. Ongoing and future work in our laboratory is therefore directed determining the feasibility of using algae as a component of a BLSS in space.

Free-Suspension Residual Flexibility Testing of Space Station Pathfinder: Comparison to Fixed-Base Results

NASA Technical Reports Server (NTRS)

Tinker, Michael L.

1998-01-01

Application of the free-suspension residual flexibility modal test method to the International Space Station Pathfinder structure is described. The Pathfinder, a large structure of the general size and weight of Space Station module elements, was also tested in a large fixed-base fixture to simulate Shuttle Orbiter payload constraints. After correlation of the Pathfinder finite element model to residual flexibility test data, the model was coupled to a fixture model, and constrained modes and frequencies were compared to fixed-base test. modes. The residual flexibility model compared very favorably to results of the fixed-base test. This is the first known direct comparison of free-suspension residual flexibility and fixed-base test results for a large structure. The model correlation approach used by the author for residual flexibility data is presented. Frequency response functions (FRF) for the regions of the structure that interface with the environment (a test fixture or another structure) are shown to be the primary tools for model correlation that distinguish or characterize the residual flexibility approach. A number of critical issues related to use of the structure interface FRF for correlating the model are then identified and discussed, including (1) the requirement of prominent stiffness lines, (2) overcoming problems with measurement noise which makes the antiresonances or minima in the functions difficult to identify, and (3) the use of interface stiffness and lumped mass perturbations to bring the analytical responses into agreement with test data. It is shown that good comparison of analytical-to-experimental FRF is the key to obtaining good agreement of the residual flexibility values.

Active space debris removal by using laser propulsion

NASA Astrophysics Data System (ADS)

Rezunkov, Yu. A.

2013-03-01

At present, a few projects on the space debris removal by using highpower lasers are developed. One of the established projects is the ORION proposed by Claude Phipps from Photonics Associates Company and supported by NASA (USA) [1]. But the technical feasibility of the concept is limited by sizes of the debris objects (from 1 to 10 cm) because of a small thrust impulse generated at the laser ablation of the debris materials. At the same time, the removal of rocket upper stages and satellites, which have reached the end of their lives, has been carried out only in a very small number of cases and most of them remain on the Low Earth Orbits (LEO). To reduce the amount of these large-size objects, designing of space systems allowing deorbiting upper rocket stages and removing large-size satellite remnants from economically and scientifically useful orbits to disposal ones is considered. The suggested system is based on high-power laser propulsion. Laser-Orbital Transfer Vehicle (LOTV) with the developed aerospace laser propulsion engine is considered as applied to the problem of mitigation of man-made large-size space debris in LEO.

Plate motions and deformations from geologic and geodetic data

NASA Technical Reports Server (NTRS)

Jordan, Thomas H.

1990-01-01

An analysis of geodetic data in the vicinity of the Crustal Dynamics Program (CDP) site at Vandenberg Air Force Base (VNDN) is presented. The utility of space-geodetic data in the monitoring of transient strains associated with earthquakes in tectonically active areas like California is investigated. Particular interest is in the possibility that space-geodetic methods may be able to provide critical new data on deformations precursory to large seismic events. Although earthquake precursory phenomena are not well understood, the monitoring of small strains in the vicinity of active faults is a promising technique for studying the mechanisms that nucleate large earthquakes and, ultimately, for earthquake prediction. Space-geodetic techniques are now capable of measuring baselines of tens to hundreds of kilometers with a precision of a few parts in 108. Within the next few years, it will be possible to record and analyze large-scale strain variations with this precision continuously in real time. Thus, space-geodetic techniques may become tools for earthquake prediction. In anticipation of this capability, several questions related to the temporal and spatial scales associated with subseismic deformation transients are examined.

Evaluation of installed solar systems at Navy, Army, and Air Force Bases. Final report, October 1984-September 1985

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

Durlak, E.R.

1986-05-01

This report presents a summary of the results of site-evaluation inspection conducted at Navy, Army, and Air Force base. The solar systems evaluated included space heating, space cooling, and domestic hot water system. The systems range in size from small two-collector systems to large arrays installed on barracks, mess halls, office buildings, etc. These operational results are presented so that future designs will benefit from the lesson learned in this study.

Test Frame for Gravity Offload Systems

NASA Technical Reports Server (NTRS)

Murray, Alexander R.

2005-01-01

Advances in space telescope and aperture technology have created a need to launch larger structures into space. Traditional truss structures will be too heavy and bulky to be effectively used in the next generation of space-based structures. Large deployable structures are a possible solution. By packaging deployable trusses, the cargo volume of these large structures greatly decreases. The ultimate goal is to three dimensionally measure a boom's deployment in simulated microgravity. This project outlines the construction of the test frame that supports a gravity offload system. The test frame is stable enough to hold the gravity offload system and does not interfere with deployment of, or vibrations in, the deployable test boom. The natural frequencies and stability of the frame were engineered in FEMAP. The test frame was developed to have natural frequencies that would not match the first two modes of the deployable beam. The frame was then modeled in Solidworks and constructed. The test frame constructed is a stable base to perform studies on deployable structures.

Large Field of View PIV Measurements of Air Entrainment by SLS SMAT Water Sound Suppression System

NASA Astrophysics Data System (ADS)

Stegmeir, Matthew; Pothos, Stamatios; Bissell, Dan

2015-11-01

Water-based sound suppressions systems have been used to reduce the acoustic impact of space vehicle launches. Water flows at a high rate during launch in order to suppress Engine Generated Acoustics and other potentially damaging sources of noise. For the Space Shuttle, peak flow rates exceeded 900,000 gallons per minute. Such large water flow rates have the potential to induce substantial entrainment of the surrounding air, affecting the launch conditions and generating airflow around the launch vehicle. Validation testing is necessary to quantify this impact for future space launch systems. In this study, PIV measurements were performed to map the flow field above the SMAT sub-scale launch vehicle scaled launch stand. Air entrainment effects generated by a water-based sound suppression system were studied. Mean and fluctuating fluid velocities were mapped up to 1m above the test stand deck and compared to simulation results. Measurements performed with NASA MSFC.

AlphaSpace: Fragment-Centric Topographical Mapping To Target Protein–Protein Interaction Interfaces

PubMed Central

2016-01-01

Inhibition of protein–protein interactions (PPIs) is emerging as a promising therapeutic strategy despite the difficulty in targeting such interfaces with drug-like small molecules. PPIs generally feature large and flat binding surfaces as compared to typical drug targets. These features pose a challenge for structural characterization of the surface using geometry-based pocket-detection methods. An attractive mapping strategy—that builds on the principles of fragment-based drug discovery (FBDD)—is to detect the fragment-centric modularity at the protein surface and then characterize the large PPI interface as a set of localized, fragment-targetable interaction regions. Here, we introduce AlphaSpace, a computational analysis tool designed for fragment-centric topographical mapping (FCTM) of PPI interfaces. Our approach uses the alpha sphere construct, a geometric feature of a protein’s Voronoi diagram, to map out concave interaction space at the protein surface. We introduce two new features—alpha-atom and alpha-space—and the concept of the alpha-atom/alpha-space pair to rank pockets for fragment-targetability and to facilitate the evaluation of pocket/fragment complementarity. The resulting high-resolution interfacial map of targetable pocket space can be used to guide the rational design and optimization of small molecule or biomimetic PPI inhibitors. PMID:26225450

Nature-Based Strategies for Improving Urban Health and Safety.

PubMed

Kondo, Michelle C; South, Eugenia C; Branas, Charles C

2015-10-01

Place-based programs are being noticed as key opportunities to prevent disease and promote public health and safety for populations at-large. As one key type of place-based intervention, nature-based and green space strategies can play an especially large role in improving health and safety for dwellers in urban environments such as US legacy cities that lack nature and greenery. In this paper, we describe the current understanding of place-based influences on public health and safety. We focus on nonchemical environmental factors, many of which are related to urban abandonment and blight. We then review findings from studies of nature-based interventions regarding impacts on health, perceptions of safety, and crime. Based on our findings, we suggest that further research in this area will require (1) refined measures of green space, nature, and health and safety for cities, (2) interdisciplinary science and cross-sector policy collaboration, (3) observational studies as well as randomized controlled experiments and natural experiments using appropriate spatial counterfactuals and mixed methods, and (4) return-on-investment calculations of potential economic, social, and health costs and benefits of urban greening initiatives.

The Laser Interferometer Space Antenna: A space-based Gravitational Wave Observatory

NASA Astrophysics Data System (ADS)

Thorpe, James Ira; McNamara, Paul

2018-01-01

After decades of persistence, scientists have recently developed facilities which can measure the vibrations of spacetime caused by astrophysical cataclysms such as the mergers of black holes and neutron stars. The first few detections have presented some interesting astrophysical questions and it is clear that with an increase in the number and capability of ground-based facilities, gravitational waves will become an important tool for astronomy. A space-based observatory will complement these efforts by providing access to the milliHertz gravitational wave band, which is expected to be rich in both number and variety of sources. The European Space Agency (ESA) has recently selected the Laser Interferometer Space Antenna (LISA) as a Large-Class mission in its Cosmic Visions Programme. The modern LISA retains the basic design features of previous incarnations and, like its predecessors is expected to be a collaboration between ESA, NASA, and a number of European States. In this poster, we present an overview of the current LISA design, its scientific capabilities, and the timeline to launch.

Development of distortion measurement system for large deployable antenna via photogrammetry in vacuum and cryogenic environment

NASA Astrophysics Data System (ADS)

Zhang, Pengsong; Jiang, Shanping; Yang, Linhua; Zhang, Bolun

2018-01-01

In order to meet the requirement of high precision thermal distortion measurement foraΦ4.2m deployable mesh antenna of satellite in vacuum and cryogenic environment, based on Digital Close-range Photogrammetry and Space Environment Test Technology of Spacecraft, a large scale antenna distortion measurement system under vacuum and cryogenic environment is developed in this paper. The antenna Distortion measurement system (ADMS) is the first domestic independently developed thermal distortion measurement system for large antenna, which has successfully solved non-contact high precision distortion measurement problem in large spacecraft structure under vacuum and cryogenic environment. The measurement accuracy of ADMS is better than 50 μm/5m, which has reached international advanced level. The experimental results show that the measurement system has great advantages in large structural measurement of spacecrafts, and also has broad application prospects in space or other related fields.

Preliminary Concept of Operations for the Deep Space Array-Based Network

NASA Astrophysics Data System (ADS)

Bagri, D. S.; Statman, J. I.

2004-05-01

The Deep Space Array-Based Network (DSAN) will be an array-based system, part of a greater than 1000 times increase in the downlink/telemetry capability of the Deep Space Network. The key function of the DSAN is provision of cost-effective, robust telemetry, tracking, and command services to the space missions of NASA and its international partners. This article presents an expanded approach to the use of an array-based system. Instead of using the array as an element in the existing Deep Space Network (DSN), relying to a large extent on the DSN infrastructure, we explore a broader departure from the current DSN, using fewer elements of the existing DSN, and establishing a more modern concept of operations. For example, the DSAN will have a single 24 x 7 monitor and control (M&C) facility, while the DSN has four 24 x 7 M&C facilities. The article gives the architecture of the DSAN and its operations philosophy. It also briefly describes the customer's view of operations, operations management, logistics, anomaly analysis, and reporting.

Propulsion of space ships by nuclear explosion

NASA Astrophysics Data System (ADS)

Linhart, J. G.; Kravárik, J.

2005-01-01

Recent progress in the research on deuterium-tritium (D-T) inertially confined microexplosions encourages one to reconsider the nuclear propulsion of spaceships based on the concept originally proposed in the Orion project. We discuss first the acceleration of medium-sized spaceships by D-T explosions whose output is in the range of 0.1 10 t of TNT. The launching of such a ship into an Earth orbit or beyond by a large nuclear explosion in an underground cavity is sketched out in the second section of the paper, and finally we consider a hypothetical Mars mission based on these concepts. In the conclusion it is argued that propulsion based on the Orion concept only is not the best method for interplanetary travel owing to the very large number of nuclear explosion required. A combination of a super gun and subsequent rocket propulsion using advanced chemical fuels appears to be the best solution for space flights of the near future.

Promoting access to and use of seismic data in a large scientific community. SpaceInn data handling and archiving

NASA Astrophysics Data System (ADS)

Michel, Eric; Belkacem, Kevin; Samadi, Reza; Assis Peralta, Raphael de; Renié, Christian; Abed, Mahfoudh; Lin, Guangyuan; Christensen-Dalsgaard, Jørgen; Houdek, Günter; Handberg, Rasmus; Gizon, Laurent; Burston, Raymond; Nagashima, Kaori; Pallé, Pere; Poretti, Ennio; Rainer, Monica; Mistò, Angelo; Panzera, Maria Rosa; Roth, Markus

2017-10-01

The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS).

Feasibility of utilizing Cherenkov Telescope Array gamma-ray telescopes as free-space optical communication ground stations.

PubMed

Carrasco-Casado, Alberto; Vilera, Mariafernanda; Vergaz, Ricardo; Cabrero, Juan Francisco

2013-04-10

The signals that will be received on Earth from deep-space probes in future implementations of free-space optical communication will be extremely weak, and new ground stations will have to be developed in order to support these links. This paper addresses the feasibility of using the technology developed in the gamma-ray telescopes that will make up the Cherenkov Telescope Array (CTA) observatory in the implementation of a new kind of ground station. Among the main advantages that these telescopes provide are the much larger apertures needed to overcome the power limitation that ground-based gamma-ray astronomy and optical communication both have. Also, the large number of big telescopes that will be built for CTA will make it possible to reduce costs by economy-scale production, enabling optical communications in the large telescopes that will be needed for future deep-space links.

Operation's Concept for Array-Based Deep Space Network

NASA Technical Reports Server (NTRS)

Bagri, Durgadas S.; Statman, Joseph I.; Gatti, Mark S.

2005-01-01

The Array-based Deep Space Network (DSNArray) will be a part of more than 10(exp 3) times increase in the downlink/telemetry capability of the Deep space Network (DSN). The key function of the DSN-Array is to provide cost-effective, robust Telemetry, Tracking and Command (TT&C) services to the space missions of NASA and its international partners. It provides an expanded approach to the use of an array-based system. Instead of using the array as an element in the existing DSN, relying to a large extent on the DSN infrastructure, we explore a broader departure from the current DSN, using fewer elements of the existing DSN, and establishing a more modern Concept of Operations. This paper gives architecture of DSN-Array and its operation's philosophy. It also describes customer's view of operations, operations management and logistics - including maintenance philosophy, anomaly analysis and reporting.

Improvement of Automated POST Case Success Rate Using Support Vector Machines

NASA Technical Reports Server (NTRS)

Zwack, Mathew R.; Dees, Patrick D.

2017-01-01

During early conceptual design of complex systems, concept down selection can have a large impact upon program life-cycle cost. Therefore, any concepts selected during early design will inherently commit program costs and affect the overall probability of program success. For this reason it is important to consider as large a design space as possible in order to better inform the down selection process. For conceptual design of launch vehicles, trajectory analysis and optimization often presents the largest obstacle to evaluating large trade spaces. This is due to the sensitivity of the trajectory discipline to changes in all other aspects of the vehicle design. Small deltas in the performance of other subsystems can result in relatively large fluctuations in the ascent trajectory because the solution space is non-linear and multi-modal. In order to help capture large design spaces for new launch vehicles, the authors have performed previous work seeking to automate the execution of the industry standard tool, Program to Optimize Simulated Trajectories (POST). This work initially focused on implementation of analyst heuristics to enable closure of cases in an automated fashion, with the goal of applying the concepts of design of experiments (DOE) and surrogate modeling to enable near instantaneous throughput of vehicle cases.3 As noted in [4] work was then completed to improve the DOE process by utilizing a graph theory based approach to connect similar design points.

Evaluation of solar cells for potential space satellite power applications

NASA Technical Reports Server (NTRS)

1977-01-01

The evaluation focused on the following subjects: (1) the relative merits of alternative solar cell materials, based on performance and availability, (2) the best manufacturing methods for various solar cell options and the effects of extremely large production volumes on their ultimate costs and operational characteristics, (3) the areas of uncertainty in achieving large solar cell production volumes, (4) the effects of concentration ratios on solar array mass and system performance, (5) the factors influencing solar cell life in the radiation environment during transport to and in geosynchronous orbit, and (6) the merits of conducting solar cell manufacturing operations in space.

Characterising the large coherence length at diamond’s beamline I13L

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

Wagner, U. H., E-mail: ulrich.wagner@diamond.ac.uk; Parsons, A.; Rahomaki, J.

2016-07-27

I13 is a 250 m long hard x-ray beamline (6 keV to 35 keV) at the Diamond Light Source. The beamline comprises of two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques [1]. An outstanding feature of the coherence branch, due to its length and a new generation of ultra-stable beamline instrumentation [2], is its capability of delivering a very large coherence length well beyond 200 μm, providing opportunities for unique x-ray optical experiments. In this paper we discuss the challenges of measuringmore » a large coherence length and present quantitative measurement based on analyzing diffraction patterns from a boron fiber [3]. We also discuss the limitations of this classical method in respect to detector performance, very short and long coherence lengths. Furthermore we demonstrate how a Ronchi grating setup [4] can be used to quickly establish if the beam is coherent over a large area.« less

On public space design for Chinese urban residential area based on integrated architectural physics environment evaluation

NASA Astrophysics Data System (ADS)

Dong, J. Y.; Cheng, W.; Ma, C. P.; Tan, Y. T.; Xin, L. S.

2017-04-01

The residential public space is an important part in designing the ecological residence, and a proper physics environment of public space is of greater significance to urban residence in China. Actually, the measure to apply computer aided design software into residential design can effectively avoid an inconformity of design intent with actual using condition, and a negative impact on users due to bad architectural physics environment of buildings, etc. The paper largely adopts a design method of analyzing architectural physics environment of residential public space. By analyzing and evaluating various physics environments, a suitability assessment is obtained for residential public space, thereby guiding the space design.

Large Space Systems Technology, 1979. [antenna and space platform systems conference

NASA Technical Reports Server (NTRS)

Ward, J. C., Jr. (Compiler)

1980-01-01

Items of technology and developmental efforts in support of the large space systems technology programs are described. The major areas of interest are large antennas systems, large space platform systems, and activities that support both antennas and platform systems.

Progress Towards a Space-Based Gravitational-Wave Observatory Since 2010

NASA Technical Reports Server (NTRS)

Stebbins, Robin T.

2015-01-01

Laser Interferometer Space Antenna (LISA): Focus of all work since 1993; Unchanged since 1997; Project in Phase A since 2004; Extensive formulation work and products; Reviewed and recommended in many major reviews: AANM (NRC, 2001), TRIP (HQ, 2003), Connecting Quarks with the Cosmos (NRC, 2003), AETD (GSFC, 2005). Beyond Einstein Program: (NRC, 2007), NWNH (NRC, 2010): Second in large space projects after WFIRST. Recommended for a new start. Contingent on Lisa Pathfinder success and a roughly 50-50 European partnership.

Space optics with silicon wafers and slumped glass

NASA Astrophysics Data System (ADS)

Hudec, R.; Semencova, V.; Inneman, A.; Skulinova, M.; Sveda, L.; Míka, M.; Sik, J.; Lorenc, M.

2017-11-01

The future space X-ray astronomy imaging missions require very large collecting areas at still fine angular resolution and reasonable weight. The novel substrates for X-ray mirrors such as Silicon wafers and thin thermally formed glass enable wide applications of precise and very light weight (volume densities 2.3 to 2.5 gcm-3) optics. The recent status of novel technologies as well as developed test samples with emphasis on precise optical surfaces based on novel materials and their space applications is presented and discussed.

Development of a large scale Chimera grid system for the Space Shuttle Launch Vehicle

NASA Technical Reports Server (NTRS)

Pearce, Daniel G.; Stanley, Scott A.; Martin, Fred W., Jr.; Gomez, Ray J.; Le Beau, Gerald J.; Buning, Pieter G.; Chan, William M.; Chiu, Ing-Tsau; Wulf, Armin; Akdag, Vedat

1993-01-01

The application of CFD techniques to large problems has dictated the need for large team efforts. This paper offers an opportunity to examine the motivations, goals, needs, problems, as well as the methods, tools, and constraints that defined NASA's development of a 111 grid/16 million point grid system model for the Space Shuttle Launch Vehicle. The Chimera approach used for domain decomposition encouraged separation of the complex geometry into several major components each of which was modeled by an autonomous team. ICEM-CFD, a CAD based grid generation package, simplified the geometry and grid topology definition by provoding mature CAD tools and patch independent meshing. The resulting grid system has, on average, a four inch resolution along the surface.

Structural stiffness, strength and dynamic characteristics of large tetrahedral space truss structures

NASA Technical Reports Server (NTRS)

Mikulas, M. M., Jr.; Bush, H. G.; Card, M. F.

1977-01-01

Physical characteristics of large skeletal frameworks for space applications are investigated by analyzing one concept: the tetrahedral truss, which is idealized as a sandwich plate with isotropic faces. Appropriate analytical relations are presented in terms of the truss column element properties which for calculations were taken as slender graphite/epoxy tubes. Column loads, resulting from gravity gradient control and orbital transfer, are found to be small for the class structure investigated. Fundamental frequencies of large truss structures are shown to be an order of magnitude lower than large earth based structures. Permissible loads are shown to result in small lateral deflections of the truss due to low-strain at Euler buckling of the slender graphite/epoxy truss column elements. Lateral thermal deflections are found to be a fraction of the truss depth using graphite/epoxy columns.

The USGS geomagnetism program and its role in space weather monitoring

USGS Publications Warehouse

Love, Jeffrey J.; Finn, Carol A.

2011-01-01

Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring.

The USGS Geomagnetism Program and its role in Space-Weather Monitoring

USGS Publications Warehouse

Love, Jeffrey J.; Finn, Carol A.

2011-01-01

Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring.

Validation of a unique concept for a low-cost, lightweight space-deployable antenna structure

NASA Technical Reports Server (NTRS)

Freeland, R. E.; Bilyeu, G. D.; Veal, G. R.

1993-01-01

An experiment conducted in the framework of a NASA In-Space Technology Experiments Program based on a concept of inflatable deployable structures is described. The concept utilizes very low inflation pressure to maintain the required geometry on orbit and gravity-induced deflection of the structure precludes any meaningful ground-based demonstrations of functions performance. The experiment is aimed at validating and characterizing the mechanical functional performance of a 14-m-diameter inflatable deployable reflector antenna structure in the orbital operational environment. Results of the experiment are expected to significantly reduce the user risk associated with using large space-deployable antennas by demonstrating the functional performance of a concept that meets the criteria for low-cost, lightweight, and highly reliable space-deployable structures.

Spacecraft crew procedures from paper to computers

NASA Technical Reports Server (NTRS)

Oneal, Michael; Manahan, Meera

1993-01-01

Large volumes of paper are launched with each Space Shuttle Mission that contain step-by-step instructions for various activities that are to be performed by the crew during the mission. These instructions include normal operational procedures and malfunction or contingency procedures and are collectively known as the Flight Data File (FDF). An example of nominal procedures would be those used in the deployment of a satellite from the Space Shuttle; a malfunction procedure would describe actions to be taken if a specific problem developed during the deployment. A new FDF and associated system is being created for Space Station Freedom. The system will be called the Space Station Flight Data File (SFDF). NASA has determined that the SFDF will be computer-based rather than paper-based. Various aspects of the SFDF are discussed.

Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST)

NASA Astrophysics Data System (ADS)

Baldauf, Brian; Conti, Alberto

2016-01-01

The "Search for Life" via imaging of exoplanets is a mission that requires extremely stable telescopes with apertures in the 10 m to 20 m range. The High Definition Space Telescope (HDST) envisioned for this mission would have an aperture >10 m, which is a larger payload than what can be delivered to space using a single launch vehicle. Building and assembling the mirror segments enabling large telescopes will likely require multiple launches and assembly in space. Space-based telescopes with large apertures will require major changes to system architectures.The Optical Telescope Assembly (OTA) for HDST is a primary mission cost driver. Enabling and affordable solutions for this next generation of large aperture space-based telescope are needed.This paper reports on the concept for the Modular Orbital Demonstration of an Evolvable Space Telescope (MODEST), which demonstrates on-orbit robotic and/or astronaut assembly of a precision optical telescope in space. It will also facilitate demonstration of active correction of phase and mirror shape. MODEST is proposed to be delivered to the ISS using standard Express Logistics Carriers (ELCs) and can mounted to one of a variety of ISS pallets. Post-assembly value includes space, ground, and environmental studies, and a testbed for new instruments. This demonstration program for next generation mirror technology provides significant risk reduction and demonstrates the technology in a six-mirror phased telescope. Other key features of the demonstration include the use of an active primary optical surface with wavefront feedback control that allows on-orbit optimization and demonstration of precise surface control to meet optical system wavefront and stability requirements.MODEST will also be used to evaluate advances in lightweight mirror and metering structure materials such as SiC or Carbon Fiber Reinforced Polymer that have excellent mechanical and thermal properties, e.g. high stiffness, high modulus, high thermal conductivity, and low thermal expansion. It has been demonstrated that mirrors built from these materials can be rapidly replicated in a highly cost effective manner, making these materials excellent candidates for a low cost, high performance OTA.

Structural load control during construction

NASA Technical Reports Server (NTRS)

Mikulas, Martin M., Jr.

1991-01-01

In the absence of gravitational pull, the major design considerations for large space structures are stiffness for controllability, and transient dynamic loadings (as opposed to the traditional static load associated with earth-based structures). Because of the absence of gravitational loading, space structures can be designed to be significantly lighter than their counterparts on Earth. For example, the Space Shuttle manipulator arm is capable of moving and positioning a 60,000 lb payload, yet weighs less than 1,000 lbs. A recent design for the Space Station which had a total weight of about 500,000 lbs. used a primary loadcarrying keel beam which weighed less than 10,000 lbs. For many large space structures designs it is quite common for the load-carrying structure to have a mass fraction on the order of one or two percent of the total spacecraft mass. This significant weight reduction for large space structures is commonly accompanied by very low natural frequencies. These low frequencies cause an unprecedented level of operational complexity for mission applications which require a high level of positioning and control accuracy. This control problem is currently the subject of considerable research directed towards reducing the flexibility problem. In addition, however, the small mass fraction typically results in structures which are quite unforgiving to inadvertent high loadings. In other words, the structures are 'fragile.' In order to deal with the fragility issue CSC developed a load-limiting concept for space truss structures. This concept is aimed at limiting the levels of load which can occur in a large space structure during the construction process as well as during subsequent operations. Currently, the approach for dealing with large loadings is to make the structure larger. The impact this has on construction is significant. The larger structures are more difficult to package in the launch vehicle, and in fact in some instances the concept must be changed from a deployable truss to an erectable truss to permit packaging. The new load-limiting concept is aimed at permitting the use in large space structures of smaller trusses with a high level of strength robustness, in order to simplify the construction process. To date several analyses conducted on the concept have demonstrated its feasibility, and an experiment is currently being designed to demonstrate its operation.

Lunar base mission technology issues and orbital demonstration requirements on space station

NASA Technical Reports Server (NTRS)

Llewellyn, Charles P.; Weidman, Deene J.

1992-01-01

The International Space Station has been the object of considerable design, redesign, and alteration since it was originally proposed in early 1984. In the intervening years the station has slowly evolved to a specific design that was thoroughly reviewed by a large agency-wide Critical Evaluation Task Force (CETF). As space station designs continue to evolve, studies must be conducted to determine the suitability of the current design for some of the primary purposes for which the station will be used. This paper concentrates on the technology requirements and issues, the on-orbit demonstration and verification program, and the space station focused support required prior to the establishment of a permanently manned lunar base as identified in the National Commission on Space report. Technology issues associated with the on-orbit assembly and processing of the lunar vehicle flight elements are also discussed.

A methodology for selecting optimum organizations for space communities

NASA Technical Reports Server (NTRS)

Ragusa, J. M.

1978-01-01

This paper suggests that a methodology exists for selecting optimum organizations for future space communities of various sizes and purposes. Results of an exploratory study to identify an optimum hypothetical organizational structure for a large earth-orbiting multidisciplinary research and applications (R&A) Space Base manned by a mixed crew of technologists are presented. Since such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than the empirical testing of it. The principal finding of this research was that a four-level project type 'total matrix' model will optimize the effectiveness of Space Base technologists. An overall conclusion which can be reached from the research is that application of this methodology, or portions of it, may provide planning insights for the formal organizations which will be needed during the Space Industrialization Age.

Navigation of space VLBI missions: Radioastron and VSOP

NASA Technical Reports Server (NTRS)

Ellis, Jordan

1993-01-01

In the mid-1990s, Russian and Japanese space agencies will each place into highly elliptic earth orbit a radio telescope consisting of a large antenna and radio astronomy receivers. Very long baseline interferometry (VLBI) techniques will be used to obtain high resolution images of radio sources observed by the space and ground based antennas. Stringent navigation accuracy requirements are imposed on the space VLBI missions by the need to transfer an ultra-stable ground reference frequency standard to the spacecraft and by the demands of the VLBI correlation process. Orbit determination for the mission will be the joint responsibility of navigation centers in the U.S., Russia, and Japan with orbit estimates based on combining tracking data from NASA, Russian, and Japanese sites. This paper describes the operational plans, the inter-agency coordination, and data exchange between the navigation centers required for space VLBI navigation.

WSN-Based Space Charge Density Measurement System

PubMed Central

Deng, Dawei; Yuan, Haiwen; Lv, Jianxun; Ju, Yong

2017-01-01

It is generally acknowledged that high voltage direct current (HVDC) transmission line endures the drawback of large area, because of which the utilization of cable for space charge density monitoring system is of inconvenience. Compared with the traditional communication network, wireless sensor network (WSN) shows advantages in small volume, high flexibility and strong self-organization, thereby presenting great potential in solving the problem. Additionally, WSN is more suitable for the construction of distributed space charge density monitoring system as it has longer distance and higher mobility. A distributed wireless system is designed for collecting and monitoring the space charge density under HVDC transmission lines, which has been widely applied in both Chinese state grid HVDC test base and power transmission projects. Experimental results of the measuring system demonstrated its adaptability in the complex electromagnetic environment under the transmission lines and the ability in realizing accurate, flexible, and stable demands for the measurement of space charge density. PMID:28052105

WSN-Based Space Charge Density Measurement System.

PubMed

Deng, Dawei; Yuan, Haiwen; Lv, Jianxun; Ju, Yong

2017-01-01

It is generally acknowledged that high voltage direct current (HVDC) transmission line endures the drawback of large area, because of which the utilization of cable for space charge density monitoring system is of inconvenience. Compared with the traditional communication network, wireless sensor network (WSN) shows advantages in small volume, high flexibility and strong self-organization, thereby presenting great potential in solving the problem. Additionally, WSN is more suitable for the construction of distributed space charge density monitoring system as it has longer distance and higher mobility. A distributed wireless system is designed for collecting and monitoring the space charge density under HVDC transmission lines, which has been widely applied in both Chinese state grid HVDC test base and power transmission projects. Experimental results of the measuring system demonstrated its adaptability in the complex electromagnetic environment under the transmission lines and the ability in realizing accurate, flexible, and stable demands for the measurement of space charge density.

Implementation of the Boston University Space Physics Acquisition Center

NASA Technical Reports Server (NTRS)

Spence, Harlan E.

1998-01-01

The tasks carried out during this grant achieved the goals as set forth in the initial proposal. The Boston University Space Physics Acquisition CEnter (BUSPACE) now provides World Wide Web access to data from a large suite of both space-based and ground-based instruments, archived from different missions, experiments, or campaigns in which researchers associated with the Center for Space Physics (CSP) at Boston University have been involved. These archival data sets are in digital form and are valuable for retrospective data analysis studies of magnetospheric as well as ionospheric, thermospheric, and mesospheric physics. We have leveraged our grass-roots effort with the NASA seed money to establish dedicated hardware (computer and hard disk augmentation) and student support to grow and maintain the system. This leveraging of effort now permits easy access by the space physics community to many underutilized, yet important data sets, one example being that of the SCATHA satellite.

Definition of technology development missions for early space stations: Large space structures

NASA Technical Reports Server (NTRS)

1983-01-01

The testbed role of an early (1990-95) manned space station in large space structures technology development is defined and conceptual designs for large space structures development missions to be conducted at the space station are developed. Emphasis is placed on defining requirements and benefits of development testing on a space station in concert with ground and shuttle tests.

Very large virtual compound spaces: construction, storage and utility in drug discovery.

PubMed

Peng, Zhengwei

2013-09-01

Recent activities in the construction, storage and exploration of very large virtual compound spaces are reviewed by this report. As expected, the systematic exploration of compound spaces at the highest resolution (individual atoms and bonds) is intrinsically intractable. By contrast, by staying within a finite number of reactions and a finite number of reactants or fragments, several virtual compound spaces have been constructed in a combinatorial fashion with sizes ranging from 10(11)11 to 10(20)20 compounds. Multiple search methods have been developed to perform searches (e.g. similarity, exact and substructure) into those compound spaces without the need for full enumeration. The up-front investment spent on synthetic feasibility during the construction of some of those virtual compound spaces enables a wider adoption by medicinal chemists to design and synthesize important compounds for drug discovery. Recent activities in the area of exploring virtual compound spaces via the evolutionary approach based on Genetic Algorithm also suggests a positive shift of focus from method development to workflow, integration and ease of use, all of which are required for this approach to be widely adopted by medicinal chemists.

NASA/MSFC ground experiment for large space structure control verification

NASA Technical Reports Server (NTRS)

Waites, H. B.; Seltzer, S. M.; Tollison, D. K.

1984-01-01

Marshall Space Flight Center has developed a facility in which closed loop control of Large Space Structures (LSS) can be demonstrated and verified. The main objective of the facility is to verify LSS control system techniques so that on orbit performance can be ensured. The facility consists of an LSS test article which is connected to a payload mounting system that provides control torque commands. It is attached to a base excitation system which will simulate disturbances most likely to occur for Orbiter and DOD payloads. A control computer will contain the calibration software, the reference system, the alignment procedures, the telemetry software, and the control algorithms. The total system will be suspended in such a fashion that LSS test article has the characteristics common to all LSS.

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.

KSC-08pd2426

NASA Image and Video Library

2008-08-21

CAPE CANAVERAL, Fla. – The large windows of a building at NASA's Kennedy Space Center are covered by plywood and sandbags to protect against the wind and rain driven by Tropical Storm Fay. The storm passed over the center Aug. 20 and then stalled offshore, bringing with it heavy rain and tropical storm force wind. Kennedy closed Aug. 19 because of Fay and reopened for normal operations Aug. 22. Based on initial assessments, there was no damage to space flight hardware, such as the space shuttles and Hubble Space Telescope equipment. Some facilities did sustain minor damage. Photo credit: NASA/Jack Pfaller

Probabilistic load simulation: Code development status

NASA Astrophysics Data System (ADS)

Newell, J. F.; Ho, H.

1991-05-01

The objective of the Composite Load Spectra (CLS) project is to develop generic load models to simulate the composite load spectra that are included in space propulsion system components. The probabilistic loads thus generated are part of the probabilistic design analysis (PDA) of a space propulsion system that also includes probabilistic structural analyses, reliability, and risk evaluations. Probabilistic load simulation for space propulsion systems demands sophisticated probabilistic methodology and requires large amounts of load information and engineering data. The CLS approach is to implement a knowledge based system coupled with a probabilistic load simulation module. The knowledge base manages and furnishes load information and expertise and sets up the simulation runs. The load simulation module performs the numerical computation to generate the probabilistic loads with load information supplied from the CLS knowledge base.

Weak Lensing : Ground vs. Space in the Cosmos Field

NASA Astrophysics Data System (ADS)

Kasliwal, Mansi M.; Massey, R. J.; Ellis, R. S.; Rhodes, J.

2006-12-01

Weak lensing statistics are best for large numbers wide surveys with greater number of galaxies and deep surveys with a higher number density of galaxies. Although space-based surveys are unparalleled in their depth, ground-based surveys are the more cost-effective way to survey wide regions of the sky. We assess the relative merits of the two observing platforms, by using premier, multi-band, ground-based Subaru SuprimeCam data and space-based Hubble ACS data, in the 2 sq. degree COSMOS field in three ways. First, we compare shear measurements of individual galaxies and identify the relative calibration of the two datasets in terms of the largest subset in magnitude and size that is consistent. Second, we compare spaceand ground-based mass maps to quantify the relative completeness and contamination of the resulting cluster catalogs. We find that more clusters with XMM catalog counterparts are detected from space than ground and some ground-based clusters are possibly spurious detections. Third, we perform a detailed comparison of the precision with which it is possible to reconstruct the mass and size of four clusters at various redshifts identified from both ground and space. We find that the noise is much lower from space in all three investigations, but find no evidence for systematic overestimation or underestimation of the individual cluster properties by either survey.

Space propulsion

NASA Astrophysics Data System (ADS)

Kazaroff, John M.

1993-02-01

Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

Space Weather Studies Using Ground-based Experimental Complex in Kazakhstan

NASA Astrophysics Data System (ADS)

Kryakunova, O.; Yakovets, A.; Monstein, C.; Nikolayevskiy, N.; Zhumabayev, B.; Gordienko, G.; Andreyev, A.; Malimbayev, A.; Levin, Yu.; Salikhov, N.; Sokolova, O.; Tsepakina, I.

2015-12-01

Kazakhstan ground-based experimental complex for space weather study is situated near Almaty. Results of space environment monitoring are accessible via Internet on the web-site of the Institute of Ionosphere (http://www.ionos.kz/?q=en/node/21) in real time. There is a complex database with hourly data of cosmic ray intensity, geomagnetic field intensity, and solar radio flux at 10.7 cm and 27.8 cm wavelengths. Several studies using those data are reported. They are an estimation of speed of a coronal mass ejection, a study of large scale traveling distrubances, an analysis of geomagnetically induced currents using the geomagnetic field data, and a solar energetic proton event on 27 January 2012.

Taking the Politics Out of Satellite and Space-Based Communications Protocols

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2006-01-01

After many years of studies, experimentation, and deployment, large amounts of misinformation and misconceptions remain regarding applicability of various communications protocols for use in satellite and space-based networks. This paper attempts to remove much of the politics, misconceptions, and misinformation that have plagued spacebased communications protocol development and deployment. This paper provides a common vocabulary for communications; a general discussion of the requirements for various communication environments; an evaluation of tradeoffs between circuit and packet-switching technologies, and the pros and cons of various link, network, transport, application, and security protocols. Included is the applicability of protocol enhancing proxies to NASA, Department of Defense (DOD), and commercial space communication systems.

Wavefront Analysis of Adaptive Telescope

NASA Technical Reports Server (NTRS)

Hadaway, James B.; Hillman, Lloyd

1997-01-01

The motivation for this work came from a NASA Headquarters interest in investigating design concepts for a large space telescope employing active optics technology. Current and foreseeable launch vehicles will be limited to carrying around 4-5 meter diameter objects. Thus, if a large, filled-aperture telescope (6-20 meters in diameter) is to be placed in space, it will be required to have a deployable primary mirror. Such a mirror may be an inflatable membrane or a segmented mirror consisting of many smaller pieces. In any case, it is expected that the deployed primary will not be of sufficient quality to achieve diffraction-limited performance for its aperture size. Thus, an active optics system will be needed to correct for initial as well as environmentally-produced primary figure errors. Marshall Space Flight Center has developed considerable expertise in the area of active optics with the PAMELA test-bed. The combination of this experience along with the Marshall optical shop's work in mirror fabrication made MSFC the logical choice to lead NASA's effort to develop active optics technology for large, space-based, astronomical telescopes. Furthermore, UAH's support of MSFC in the areas of optical design, fabrication, and testing of space-based optical systems placed us in a key position to play a major role in the development of this future-generation telescope. A careful study of the active optics components had to be carried out in order to determine control segment size, segment quality, and segment controllability required to achieve diffraction-limited resolution with a given primary mirror. With this in mind, UAH undertook the following effort to provide NASA/MSFC with optical design and analysis support for the large telescope study. All of the work performed under this contract has already been reported, as a team member with MSFC, to NASA Headquarters in a series of presentations given between May and December of 1995. As specified on the delivery order, this report simply summarizes the material with the various UAH-written presentation packages attached as appendices.

Image-based optimization of coronal magnetic field models for improved space weather forecasting

NASA Astrophysics Data System (ADS)

Uritsky, V. M.; Davila, J. M.; Jones, S. I.; MacNeice, P. J.

2017-12-01

The existing space weather forecasting frameworks show a significant dependence on the accuracy of the photospheric magnetograms and the extrapolation models used to reconstruct the magnetic filed in the solar corona. Minor uncertainties in the magnetic field magnitude and direction near the Sun, when propagated through the heliosphere, can lead to unacceptible prediction errors at 1 AU. We argue that ground based and satellite coronagraph images can provide valid geometric constraints that could be used for improving coronal magnetic field extrapolation results, enabling more reliable forecasts of extreme space weather events such as major CMEs. In contrast to the previously developed loop segmentation codes designed for detecting compact closed-field structures above solar active regions, we focus on the large-scale geometry of the open-field coronal regions up to 1-2 solar radii above the photosphere. By applying the developed image processing techniques to high-resolution Mauna Loa Solar Observatory images, we perform an optimized 3D B-line tracing for a full Carrington rotation using the magnetic field extrapolation code developed S. Jones at al. (ApJ 2016, 2017). Our tracing results are shown to be in a good qualitative agreement with the large-scale configuration of the optical corona, and lead to a more consistent reconstruction of the large-scale coronal magnetic field geometry, and potentially more accurate global heliospheric simulation results. Several upcoming data products for the space weather forecasting community will be also discussed.

Eyeglass Large Aperture, Lightweight Space Optics FY2000 - FY2002 LDRD Strategic Initiative

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

Hyde, R

2003-02-10

A series of studies by the Air Force, the National Reconnaissance Office and NASA have identified the critical role played by large optics in fulfilling many of the space related missions of these agencies. Whether it is the Next Generation Space Telescope for NASA, high resolution imaging systems for NRO, or beam weaponry for the Air Force, the diameter of the primary optic is central to achieving high resolution (imaging) or a small spot size on target (lethality). While the detailed requirements differ for each application (high resolution imaging over the visible and near-infrared for earth observation, high damage thresholdmore » but single-wavelength operation for directed energy), the challenges of a large, lightweight primary optic which is space compatible and operates with high efficiency are the same. The advantage of such large optics to national surveillance applications is that it permits these observations to be carried-out with much greater effectiveness than with smaller optics. For laser weapons, the advantage is that it permits more tightly focused beams which can be leveraged into either greater effective range, reduced laser power, and/or smaller on-target spot-sizes; weapon systems can be made either much more effective or much less expensive. This application requires only single-wavelength capability, but places an emphasis upon robust, rapidly targetable optics. The advantages of large aperture optics to astronomy are that it increases the sensitivity and resolution with which we can view the universe. This can be utilized either for general purpose astronomy, allowing us to examine greater numbers of objects in more detail and at greater range, or it can enable the direct detection and detailed examination of extra-solar planets. This application requires large apertures (for both light-gathering and resolution reasons), with broad-band spectral capability, but does not emphasize either large fields-of-view or pointing agility. Despite differences in their requirements and implementations, the fundamental difficulty in utilizing large aperture optics is the same for all of these applications: It is extremely difficult to design large aperture space optics which are both optically precise and can meet the practical requirements for launch and deployment in space. At LLNL we have developed a new concept (Eyeglass) which uses large diffractive optics to solve both of these difficulties; greatly reducing both the mass and the tolerance requirements for large aperture optics. During previous LDRD-supported research, we developed this concept, built and tested broadband diffractive telescopes, and built 50 cm aperture diffraction-limited diffractive lenses (the largest in the world). This work is fully described in UCRL-ID-136262, Eyeglass: A Large Aperture Space Telescope. However, there is a large gap between optical proof-of-principle with sub-meter apertures, and actual 50 meter space telescopes. This gap is far too large (both in financial resources and in spacecraft expertise) to be filled internally at LLNL; implementation of large aperture diffractive space telescopes must be done externally using non-LLNL resources and expertise. While LLNL will never become the primary contractor and integrator for large space optical systems, our natural role is to enable these devices by developing the capability of producing very large diffractive optics. Accordingly, the purpose of the Large Aperture, Lightweight Space Optics Strategic Initiative was to develop the technology to fabricate large, lightweight diffractive lenses. The additional purpose of this Strategic Initiative was, of course, to demonstrate this lens-fabrication capability in a fashion compellingly enough to attract the external support necessary to continue along the path to full-scale space-based telescopes. During this 3 year effort (FY2000-FY2002) we have developed the capability of optically smoothing and diffractively-patterning thin meter-sized sheets of glass into lens panels. We have also developed alignment and seaming techniques which allow individual lens panels to be assembled together, forming a much larger, segmented, diffractive lens. The capabilities provided by this LDRD-supported developmental effort were then demonstrated by the fabrication and testing of a lightweight, 5 meter aperture, diffractive lens.« less

Cavity Resonator Wireless Power Transfer System for Freely Moving Animal Experiments.

PubMed

Mei, Henry; Thackston, Kyle A; Bercich, Rebecca A; Jefferys, John G R; Irazoqui, Pedro P

2017-04-01

The goal of this paper is to create a large wireless powering arena for powering small devices implanted in freely behaving rodents. We design a cavity resonator based wireless power transfer (WPT) system and utilize our previously developed optimal impedance matching methodology to achieve effective WPT performance for operating sophisticated implantable devices, made with miniature receive coils (<8 mm in diameter), within a large volume (dimensions: 60.96 cm × 60.96 cm × 30 cm). We provide unique cavity design and construction methods which maintains electromagnetic performance of the cavity while promoting its utility as a large animal husbandry environment. In addition, we develop a biaxial receive resonator system to address device orientation insensitivity within the cavity environment. Functionality is demonstrated with chronic experiments involving rats implanted with our custom designed bioelectric recording device. We demonstrate an average powering fidelity of 93.53% over nine recording sessions across nine weeks, indicating nearly continuous device operation for a freely behaving rat within the large cavity resonator space. We have developed and demonstrated a cavity resonator based WPT system for long term experiments involving freely behaving small animals. This cavity resonator based WPT system offers an effective and simple method for wirelessly powering miniaturized devices implanted in freely moving small animals within the largest space.

Assessing the Effect of Web-Based Learning Tools on Student Understanding of Stoichiometry Using Knowledge Space Theory

ERIC Educational Resources Information Center

Arasasingham, Ramesh D.; Taagepera, Mare; Potter, Frank; Martorell, Ingrid; Lonjers, Stacy

2005-01-01

Student achievement in web-based learning tools is assessed by using in-class examination, pretests, and posttests. The study reveals that using mastering chemistry web software in large-scale instruction provides an overall benefit to introductory chemistry students.

Effects of space plasma discharge on the performance of large antenna structures in low Earth orbit

NASA Technical Reports Server (NTRS)

Blume, Hans-Juergen C.

1987-01-01

The anomalous plasma around spacecrafts in low Earth orbit represents the coma of an artificial comet. The plasma discharge is caused by an energetic disturbance of charged particles which were formerly in a state of equilibrium. The plasma can effect the passive and active radio frequency operation of large space antennas by inducing corona discharge or strong arcing in the antenna feeds. One such large space antenna is the 15-meter hoop column antenna which consists of a mesh membrane material (tricot knitted gold plated wire) reflector and carbon fiber tension cords. The atomic oxygen in the plasma discharge state can force the wire base metal particles through the gold lattice and oxydize the metal particles to build a Schottky-barrier contact at the point where the wires meet. This effect can cause strong deviations in the reflector performance in terms of antenna pattern and losses. Also, the carbon-fiber cords can experience a strength reduction of 30 percent over a 40-hour exposure time.

Large Terrain Modeling and Visualization for Planets

NASA Technical Reports Server (NTRS)

Myint, Steven; Jain, Abhinandan; Cameron, Jonathan; Lim, Christopher

2011-01-01

Physics-based simulations are actively used in the design, testing, and operations phases of surface and near-surface planetary space missions. One of the challenges in realtime simulations is the ability to handle large multi-resolution terrain data sets within models as well as for visualization. In this paper, we describe special techniques that we have developed for visualization, paging, and data storage for dealing with these large data sets. The visualization technique uses a real-time GPU-based continuous level-of-detail technique that delivers multiple frames a second performance even for planetary scale terrain model sizes.

Efficient and automatic image reduction framework for space debris detection based on GPU technology

NASA Astrophysics Data System (ADS)

Diprima, Francesco; Santoni, Fabio; Piergentili, Fabrizio; Fortunato, Vito; Abbattista, Cristoforo; Amoruso, Leonardo

2018-04-01

In the last years, the increasing number of space debris has triggered the need of a distributed monitoring system for the prevention of possible space collisions. Space surveillance based on ground telescope allows the monitoring of the traffic of the Resident Space Objects (RSOs) in the Earth orbit. This space debris surveillance has several applications such as orbit prediction and conjunction assessment. In this paper is proposed an optimized and performance-oriented pipeline for sources extraction intended to the automatic detection of space debris in optical data. The detection method is based on the morphological operations and Hough Transform for lines. Near real-time detection is obtained using General Purpose computing on Graphics Processing Units (GPGPU). The high degree of processing parallelism provided by GPGPU allows to split data analysis over thousands of threads in order to process big datasets with a limited computational time. The implementation has been tested on a large and heterogeneous images data set, containing both imaging satellites from different orbit ranges and multiple observation modes (i.e. sidereal and object tracking). These images were taken during an observation campaign performed from the EQUO (EQUatorial Observatory) observatory settled at the Broglio Space Center (BSC) in Kenya, which is part of the ASI-Sapienza Agreement.

Power systems for production, construction, life support and operations in space

NASA Technical Reports Server (NTRS)

Sovie, Ronald J.

1988-01-01

As one looks to man's future in space it becomes obvious that unprecedented amounts of power are required for the exploration, colonization, and exploitation of space. Activities envisioned include interplanetary travel and LEO to GEO transport using electric propulsion, Earth and lunar observatories, advance space stations, free-flying manufacturing platforms, communications platforms, and eventually evolutionary lunar and Mars bases. These latter bases would start as camps with modest power requirements (kWes) and evolve to large bases as manufacturing, food production, and life support materials are developed from lunar raw materials. These latter activities require very robust power supplies (MWes). The advanced power system technologies being pursued by NASA to fulfill these future needs are described. Technologies discussed will include nuclear, photovoltaic, and solar dynamic space power systems, including energy storage, power conditioning, power transmission, and thermal management. The state-of-the-art and gains to be made by technology advancements will be discussed. Mission requirements for a variety of applications (LEO, GEO, lunar, and Martian) will be treated, and data for power systems ranging from a few kilowatts to megawatt power systems will be represented. In addition the space power technologies being initiated under NASA's new Civilian Space Technology Initiative (CSTI) and Space Leadership Planning Group Activities will be discussed.

Power systems for production, construction, life support, and operations in space

NASA Technical Reports Server (NTRS)

Sovie, Ronald J.

1988-01-01

As one looks to man's future in space it becomes obvious that unprecedented amounts of power are required for the exploration, colonization, and exploitation of space. Activities envisioned include interplanetary travel and LEO to GEO transport using electric propulsion, earth and lunar observatories, advance space stations, free-flying manufacturing platforms, communications platforms, and eventually evolutionary lunar and Mars bases. These latter bases would start as camps with modest power requirements (kWes) and evolve to large bases as manufacturing, food production, and life support materials are developed from lunar raw materials. These latter activities require very robust power supplies (MWes). The advanced power system technologies being pursued by NASA to fulfill these future needs are described. Technologies discussed will include nuclear, photovoltaic, and solar dynamic space power systems, including energy storage, power conditioning, power transmission, and thermal management. The state-of-the-art and gains to be made by technology advancements will be discussed. Mission requirements for a variety of applications (LEO, GEO, lunar, and Martian) will be treated, and data for power systems ranging from a few kilowatts to megawatt power systems will be represented. In addition the space power technologies being initiated under NASA's new Civilian Space Technology Initiative (CSTI) and Space Leadership Planning Group Activities will be discussed.

Improving orbit prediction accuracy through supervised machine learning

NASA Astrophysics Data System (ADS)

Peng, Hao; Bai, Xiaoli

2018-05-01

Due to the lack of information such as the space environment condition and resident space objects' (RSOs') body characteristics, current orbit predictions that are solely grounded on physics-based models may fail to achieve required accuracy for collision avoidance and have led to satellite collisions already. This paper presents a methodology to predict RSOs' trajectories with higher accuracy than that of the current methods. Inspired by the machine learning (ML) theory through which the models are learned based on large amounts of observed data and the prediction is conducted without explicitly modeling space objects and space environment, the proposed ML approach integrates physics-based orbit prediction algorithms with a learning-based process that focuses on reducing the prediction errors. Using a simulation-based space catalog environment as the test bed, the paper demonstrates three types of generalization capability for the proposed ML approach: (1) the ML model can be used to improve the same RSO's orbit information that is not available during the learning process but shares the same time interval as the training data; (2) the ML model can be used to improve predictions of the same RSO at future epochs; and (3) the ML model based on a RSO can be applied to other RSOs that share some common features.

The improvement of GaN-based light-emitting diodes using nanopatterned sapphire substrate with small pattern spacing

NASA Astrophysics Data System (ADS)

Zhang, Yonghui; Wei, Tongbo; Wang, Junxi; Lan, Ding; Chen, Yu; Hu, Qiang; Lu, Hongxi; Li, Jinmin

2014-02-01

Self-assembly SiO2 nanosphere monolayer template is utilized to fabricate nanopatterned sapphire substrates (NPSSs) with 0-nm, 50-nm, and 120-nm spacing, receptively. The GaN growth on top of NPSS with 0-nm spacing has the best crystal quality because of laterally epitaxial overgrowth. However, GaN growth from pattern top is more difficult to get smooth surface than from pattern bottom. The rougher surface may result in a higher work voltage. The stimulation results of finite-difference time-domain (FDTD) display that too large or too small spacing lead to the reduced light extracted efficiency (LEE) of LEDs. Under a driving current 350 mA, the external quantum efficiencies (EQE) of GaN-based LEDs grown on NPSSs with 0-nm, 50-nm, and 120-nm spacing increase by 43.3%, 50.6%, and 39.1%, respectively, compared to that on flat sapphire substrate (FSS). The optimized pattern spacing is 50 nm for the NPSS with 600-nm pattern period.

Optical and Radio Remote Sensing of Space Plasma Turbulence

DTIC Science & Technology

2008-03-31

Helbert, Guilhelm Moreaux, Pierre-Emmanuel Godet (2006), Ground based GPS tomography of ionospheric post-seismic signal., Planet. Space. Science, 54...occurring and radio wave-induced ionospheric plasma turbulence. The intriguing phenomena reported here include large-scale turbulence created by tsunami...in Puerto Rico [Labno et al., J. Geophys. Res., 2007]. Presented are ionospheric measurements using Arecibo 430 MHz radar supported by data from

Optimizing Orbital Debris Monitoring with Optical Telescopes

DTIC Science & Technology

2010-09-01

poses an increasing risk to manned space missions and operational satellites ; however, the majority of debris large enough to cause catastrophic...cameras hosted on GEO- based satellites for monitoring GEO. Performance analysis indicates significant potential contributions of these systems as a...concerns over the long term-viability of the space environment and the resulting economic impacts. The 2007 China anti- satellite test and the 2009

Space construction base control system

NASA Technical Reports Server (NTRS)

Kaczynski, R. F.

1979-01-01

Several approaches for an attitude control system are studied and developed for a large space construction base that is structurally flexible. Digital simulations were obtained using the following techniques: (1) the multivariable Nyquist array method combined with closed loop pole allocation, (2) the linear quadratic regulator method. Equations for the three-axis simulation using the multilevel control method were generated and are presented. Several alternate control approaches are also described. A technique is demonstrated for obtaining the dynamic structural properties of a vehicle which is constructed of two or more submodules of known dynamic characteristics.

Asteroid Redirect Mission Concept: A Bold Approach for Utilizing Space Resources

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Merrill, Raymond G.; Brophy, John R.; Mueller, Robert P.

2014-01-01

The utilization of natural resources from asteroids is an idea that is older than the Space Age. The technologies are now available to transform this endeavour from an idea into reality. The Asteroid Redirect Mission (ARM) is a mission concept which includes the goal of robotically returning a small Near-Earth Asteroid (NEA) or a multi-ton boulder from a large NEA to cislunar space in the mid 2020's using an advanced Solar Electric Propulsion (SEP) vehicle and currently available technologies. The paradigm shift enabled by the ARM concept would allow in-situ resource utilization (ISRU) to be used at the human mission departure location (i.e., cislunar space) versus exclusively at the deep-space mission destination. This approach drastically reduces the barriers associated with utilizing ISRU for human deep-space missions. The successful testing of ISRU techniques and associated equipment could enable large-scale commercial ISRU operations to become a reality and enable a future space-based economy utilizing processed asteroidal materials. This paper provides an overview of the ARM concept and discusses the mission objectives, key technologies, and capabilities associated with the mission, as well as how the ARM and associated operations would benefit humanity's quest for the exploration and settlement of space.

New developments in Indian space policies and programmes—The next five years

NASA Astrophysics Data System (ADS)

Sridhara Murthi, K. R.; Bhaskaranarayana, A.; Madhusudana, H. N.

2010-02-01

Over past four decades Indian space programme has systematically acquired capabilities in space technologies and implemented its programmes with a high level of focus on societal applications. It is developed into a multi-dimensional programme where its strategy is directed towards diverse stake holders and actors such as government, users and beneficiaries including general public, industrial suppliers as well as customers, academia and other space agencies/international organisations. Over the next five years, the Indian space programme has charted an ambitious set of policies and programmes that aim to enhance impacts on society. The major task is to enlarge and diversify the services delivered to a large section of population affected by income, connectivity and digital divides. While efficacy of application of space based systems have been proven in several fields such as tele-education, water resources management, improving productivity of land and out reaching quality health services and others, the crux of the problem is to evolve sustainable and scalable delivery mechanisms on a very large scale and extending over large geographical areas. Essentially the problem shifts from being predominately a technology problem to one of a composite of economic, cultural and social problems. Tackling such problems would need renewal of policies relating to commercial as well as public service systems. Major programmatic initiatives are planned in the next five years involving new and upgraded technologies to expand services from space to fill the gaps and to improve economic efficiency. Thrust is also given to science and exploration mission beyond Chandrayaan-1 and some initial steps for the participation in human space flight. This paper discusses the policy and strategy perspectives of the programmes planned by Indian Space Research Organisation over next five years.

Space Weather Research at the National Science Foundation

NASA Astrophysics Data System (ADS)

Moretto, T.

2015-12-01

There is growing recognition that the space environment can have substantial, deleterious, impacts on society. Consequently, research enabling specification and forecasting of hazardous space effects has become of great importance and urgency. This research requires studying the entire Sun-Earth system to understand the coupling of regions all the way from the source of disturbances in the solar atmosphere to the Earth's upper atmosphere. The traditional, region-based structure of research programs in Solar and Space physics is ill suited to fully support the change in research directions that the problem of space weather dictates. On the observational side, dense, distributed networks of observations are required to capture the full large-scale dynamics of the space environment. However, the cost of implementing these is typically prohibitive, especially for measurements in space. Thus, by necessity, the implementation of such new capabilities needs to build on creative and unconventional solutions. A particularly powerful idea is the utilization of new developments in data engineering and informatics research (big data). These new technologies make it possible to build systems that can collect and process huge amounts of noisy and inaccurate data and extract from them useful information. The shift in emphasis towards system level science for geospace also necessitates the development of large-scale and multi-scale models. The development of large-scale models capable of capturing the global dynamics of the Earth's space environment requires investment in research team efforts that go beyond what can typically be funded under the traditional grants programs. This calls for effective interdisciplinary collaboration and efficient leveraging of resources both nationally and internationally. This presentation will provide an overview of current and planned initiatives, programs, and activities at the National Science Foundation pertaining to space weathe research.

The decomposition of deformation: New metrics to enhance shape analysis in medical imaging.

PubMed

Varano, Valerio; Piras, Paolo; Gabriele, Stefano; Teresi, Luciano; Nardinocchi, Paola; Dryden, Ian L; Torromeo, Concetta; Puddu, Paolo E

2018-05-01

In landmarks-based Shape Analysis size is measured, in most cases, with Centroid Size. Changes in shape are decomposed in affine and non affine components. Furthermore the non affine component can be in turn decomposed in a series of local deformations (partial warps). If the extent of deformation between two shapes is small, the difference between Centroid Size and m-Volume increment is barely appreciable. In medical imaging applied to soft tissues bodies can undergo very large deformations, involving large changes in size. The cardiac example, analyzed in the present paper, shows changes in m-Volume that can reach the 60%. We show here that standard Geometric Morphometrics tools (landmarks, Thin Plate Spline, and related decomposition of the deformation) can be generalized to better describe the very large deformations of biological tissues, without losing a synthetic description. In particular, the classical decomposition of the space tangent to the shape space in affine and non affine components is enriched to include also the change in size, in order to give a complete description of the tangent space to the size-and-shape space. The proposed generalization is formulated by means of a new Riemannian metric describing the change in size as change in m-Volume rather than change in Centroid Size. This leads to a redefinition of some aspects of the Kendall's size-and-shape space without losing Kendall's original formulation. This new formulation is discussed by means of simulated examples using 2D and 3D platonic shapes as well as a real example from clinical 3D echocardiographic data. We demonstrate that our decomposition based approaches discriminate very effectively healthy subjects from patients affected by Hypertrophic Cardiomyopathy. Copyright © 2018 Elsevier B.V. All rights reserved.

Inflatable habitation for the lunar base

NASA Technical Reports Server (NTRS)

Roberts, M.

1992-01-01

Inflatable structures have a number of advantages over rigid modules in providing habitation at a lunar base. Some of these advantages are packaging efficiency, convenience of expansion, flexibility, and psychological benefit to the inhabitants. The relatively small, rigid cylinders fitted to the payload compartment of a launch vehicle are not as efficient volumetrically as a collapsible structure that fits into the same space when packaged, but when deployed is much larger. Pressurized volume is a valuable resource. By providing that resource efficiently, in large units, labor intensive external expansion (such as adding additional modules to the existing base) can be minimized. The expansive interior in an inflatable would facilitate rearrangement of the interior to suite the evolving needs of the base. This large, continuous volume would also relieve claustrophobia, enhancing habitability and improving morale. The purpose of this paper is to explore some of the aspects of inflatable habitat design, including structural, architectural, and environmental considerations. As a specific case, the conceptual design of an inflatable lunar habitat, developed for the Lunar Base Systems Study at the Johnson Space Center, is described.

Aeronomy of the Venus Upper Atmosphere

NASA Astrophysics Data System (ADS)

Gérard, J.-C.; Bougher, S. W.; López-Valverde, M. A.; Pätzold, M.; Drossart, P.; Piccioni, G.

2017-11-01

We present aeronomical observations collected using remote sensing instruments on board Venus Express, complemented with ground-based observations and numerical modeling. They are mostly based on VIRTIS and SPICAV measurements of airglow obtained in the nadir mode and at the limb above 90 km. They complement our understanding of the behavior of Venus' upper atmosphere that was largely based on Pioneer Venus observations mostly performed over thirty years earlier. Following a summary of recent spectral data from the EUV to the infrared, we examine how these observations have improved our knowledge of the composition, thermal structure, dynamics and transport of the Venus upper atmosphere. We then synthesize progress in three-dimensional modeling of the upper atmosphere which is largely based on global mapping and observations of time variations of the nitric oxide and O2 nightglow emissions. Processes controlling the escape flux of atoms to space are described. Results based on the VeRA radio propagation experiment are summarized and compared to ionospheric measurements collected during earlier space missions. Finally, we point out some unsolved and open questions generated by these recent datasets and model comparisons.

Space Biology in the 21st century

NASA Technical Reports Server (NTRS)

Halstead, Thora W.; Krauss, Robert W.

1990-01-01

Space Biology is poised to make significant contributions to science in the next century. A carefully crafted, but largely ground-based, program in the United States has evolved major questions that require answers through experiments in space. Science, scientists, and the new long-term spacecrafts designed by NASA will be available for the first time to mount a serious Space Biology effort. The scientific challenge is of such importance that success will provide countless benefits to biologically dependent areas such as medicine, food, and commerce in the decades ahead. The international community is rapidly expanding its role in this field. The United States should generate the resources that will allow progress in Space Biology to match the recognized progress made in aeronautics and the other space sciences.

Artificial intelligence applications in space and SDI: A survey

NASA Technical Reports Server (NTRS)

Fiala, Harvey E.

1988-01-01

The purpose of this paper is to survey existing and planned Artificial Intelligence (AI) applications to show that they are sufficiently advanced for 32 percent of all space applications and SDI (Space Defense Initiative) software to be AI-based software. To best define the needs that AI can fill in space and SDI programs, this paper enumerates primary areas of research and lists generic application areas. Current and planned NASA and military space projects in AI will be reviewed. This review will be largely in the selected area of expert systems. Finally, direct applications of AI to SDI will be treated. The conclusion covers the importance of AI to space and SDI applications, and conversely, their importance to AI.

Definition of technology development missions for early space stations. Large space structures, phase 2, midterm review

NASA Technical Reports Server (NTRS)

1984-01-01

The large space structures technology development missions to be performed on an early manned space station was studied and defined and the resources needed and the design implications to an early space station to carry out these large space structures technology development missions were determined. Emphasis is being placed on more detail in mission designs and space station resource requirements.

Fiber Optic Strain Measurements In Filament-Wound Graphite-Epoxy Tubes Containing Embedded Fibers

NASA Astrophysics Data System (ADS)

Rogowski, R. S.; Heyman, J. S.; Holben, M. S.; Egalon, C.; Dehart, D. W.; Doederlein, T.; Koury, J.

1989-01-01

Several planned United States Air Force (USAF) and National Aeronautics and Space Administration (NASA) space systems such as Space Based Radar (SBR), Space Based Laser (SBL), and Space Station, pose serious vibration and control issues. Their low system mass combined with their large size, precision pointing/shape control and rapid retargetting requirements, will result in an unprecedented degree of interaction between the system controller and the modes of vibration of the structure. The resulting structural vibrations and/or those caused by foreign objects impacting the space structure could seriously degrade system performance, making it virtually impossible for passive structural systems to perform their missions. Therefore an active vibration control system which will sense these natural and spurious vibrations, evaluate them and dampen them out is required. This active vibration control system must be impervious to the space environment and electromagnetic interference, have very low weight, and in essence become part of the structure itself. The concept of smart structures meets these criteria. Smart structures is defined as the embedment of sensors, actuators, and possibly microprocessors in the material which forms the structure, a concept that is particularly applicable to advanced composites. These sensors, actuators, and microprocessors will work interactively to sense, evaluate, and dampen those vibrations which pose a threat to large flexible space systems (LSS). The sensors will also be capable of sensing any degradation to the structure. The Air Force Astronautics Laboratory (AFAL) has been working in the area of dynamics and control of LSS for the past five years. Several programs involving both contractual and in-house efforts to develop sensors and actuators for controlling LSS have been initiated. Presently the AFAL is developing a large scale laboratory which will have the capacity of performing large angle retargetting manuevers and vibration analysis on LSS. Advanced composite materials have been fabricated for the last seven years, consisting mostly of rocket components such as: nozzles, payload shrouds, exit cones, and nose cones. Recently, however, AFAL has been fabricating composite components such as trusses, tubes and flat panels for space applications. Research on fiber optic sensors at NASA Langley Research Center (NASA LaRC) dates back to 1979. Recently an optical phase locked loop (OPLL) has been developed that can be used to make strain and temperature measurements. Static and dynamic strain measurements have been demonstrated using this device.' To address future space requirements, AFAL and NASA have initiated a program to design, fabricate, and experimentally test composite struts and panels with embedded sensors, actuators, and microprocessors that can be used to control vibration and motion in space structures.

Latent Semantic Analysis as a Method of Content-Based Image Retrieval in Medical Applications

ERIC Educational Resources Information Center

Makovoz, Gennadiy

2010-01-01

The research investigated whether a Latent Semantic Analysis (LSA)-based approach to image retrieval can map pixel intensity into a smaller concept space with good accuracy and reasonable computational cost. From a large set of M computed tomography (CT) images, a retrieval query found all images for a particular patient based on semantic…

Relationship between neighbourhood socioeconomic position and neighbourhood public green space availability: An environmental inequality analysis in a large German city applying generalized linear models.

PubMed

Schüle, Steffen Andreas; Gabriel, Katharina M A; Bolte, Gabriele

2017-06-01

The environmental justice framework states that besides environmental burdens also resources may be social unequally distributed both on the individual and on the neighbourhood level. This ecological study investigated whether neighbourhood socioeconomic position (SEP) was associated with neighbourhood public green space availability in a large German city with more than 1 million inhabitants. Two different measures were defined for green space availability. Firstly, percentage of green space within neighbourhoods was calculated with the additional consideration of various buffers around the boundaries. Secondly, percentage of green space was calculated based on various radii around the neighbourhood centroid. An index of neighbourhood SEP was calculated with principal component analysis. Log-gamma regression from the group of generalized linear models was applied in order to consider the non-normal distribution of the response variable. All models were adjusted for population density. Low neighbourhood SEP was associated with decreasing neighbourhood green space availability including 200m up to 1000m buffers around the neighbourhood boundaries. Low neighbourhood SEP was also associated with decreasing green space availability based on catchment areas measured from neighbourhood centroids with different radii (1000m up to 3000 m). With an increasing radius the strength of the associations decreased. Social unequally distributed green space may amplify environmental health inequalities in an urban context. Thus, the identification of vulnerable neighbourhoods and population groups plays an important role for epidemiological research and healthy city planning. As a methodical aspect, log-gamma regression offers an adequate parametric modelling strategy for positively distributed environmental variables. Copyright © 2017 Elsevier GmbH. All rights reserved.

High-Dimensional Function Approximation With Neural Networks for Large Volumes of Data.

PubMed

Andras, Peter

2018-02-01

Approximation of high-dimensional functions is a challenge for neural networks due to the curse of dimensionality. Often the data for which the approximated function is defined resides on a low-dimensional manifold and in principle the approximation of the function over this manifold should improve the approximation performance. It has been show that projecting the data manifold into a lower dimensional space, followed by the neural network approximation of the function over this space, provides a more precise approximation of the function than the approximation of the function with neural networks in the original data space. However, if the data volume is very large, the projection into the low-dimensional space has to be based on a limited sample of the data. Here, we investigate the nature of the approximation error of neural networks trained over the projection space. We show that such neural networks should have better approximation performance than neural networks trained on high-dimensional data even if the projection is based on a relatively sparse sample of the data manifold. We also find that it is preferable to use a uniformly distributed sparse sample of the data for the purpose of the generation of the low-dimensional projection. We illustrate these results considering the practical neural network approximation of a set of functions defined on high-dimensional data including real world data as well.

Phased Array-Fed Reflector (PAFR) Antenna Architectures for Space-Based Sensors

NASA Technical Reports Server (NTRS)

Cooley, Michael E.

2014-01-01

Communication link and target ranges for satellite communications (SATCOM) and space-based sensors (e.g. radars) vary from approximately 1000 km (for LEO satellites) to 35,800 km (for GEO satellites). At these long ranges, large antenna gains are required and legacy payloads have usually employed large reflectors with single beams that are either fixed or mechanically steered. For many applications, there are inherent limitations that are associated with the use of these legacy antennas/payloads. Hybrid antenna designs using Phased Array Fed Reflectors (PAFRs) provide a compromise between reflectors and Direct Radiating phased Arrays (DRAs). PAFRs provide many of the performance benefits of DRAs while utilizing much smaller, lower cost (feed) arrays. The primary limitation associated with hybrid PAFR architectures is electronic scan range; approximately +/-5 to +/- 10 degrees is typical, but this range depends on many factors. For LEO applications, the earth FOV is approximately +/-55 degrees which is well beyond the range of electronic scanning for PAFRs. However, for some LEO missions, limited scanning is sufficient or the CONOPS and space vehicle designs can be developed to incorporate a combination mechanical slewing and electronic scanning. In this paper, we review, compare and contrast various PAFR architectures with a focus on their general applicability to space missions. We compare the RF performance of various PAFR architectures and describe key hardware design and implementation trades. Space-based PAFR designs are highly multi-disciplinary and we briefly address key hardware engineering design areas. Finally, we briefly describe two PAFR antenna architectures that have been developed at Northrop Grumman.

Solar Power in Space?

DTIC Science & Technology

2012-01-01

orbit stupendously large orbital power plants—kilometers across—which collect the sun’s raw energy and beam it down to where it is needed on the earth...24-hour, large -scale power to the urban centers where the majority of humanity lives. A network of thousands of solar-power satellites (SPS) could...provide all the power required for an Earth-based population as large as 10 billion people, even for a fully developed “first world” lifestyle but

Unisys' experience in software quality and productivity management of an existing system

NASA Technical Reports Server (NTRS)

Munson, John B.

1988-01-01

A summary of Quality Improvement techniques, implementation, and results in the maintenance, management, and modification of large software systems for the Space Shuttle Program's ground-based systems is provided.

The Grassmannian Atlas: A General Framework for Exploring Linear Projections of High-Dimensional Data

DOE PAGES

Liu, S.; Bremer, P. -T; Jayaraman, J. J.; ...

2016-06-04

Linear projections are one of the most common approaches to visualize high-dimensional data. Since the space of possible projections is large, existing systems usually select a small set of interesting projections by ranking a large set of candidate projections based on a chosen quality measure. However, while highly ranked projections can be informative, some lower ranked ones could offer important complementary information. Therefore, selection based on ranking may miss projections that are important to provide a global picture of the data. Here, the proposed work fills this gap by presenting the Grassmannian Atlas, a framework that captures the global structuresmore » of quality measures in the space of all projections, which enables a systematic exploration of many complementary projections and provides new insights into the properties of existing quality measures.« less

Application of the LQG/LTR technique to robust controller synthesis for a large flexible space antenna

NASA Technical Reports Server (NTRS)

Joshi, S. M.; Armstrong, E. S.; Sundararajan, N.

1986-01-01

The problem of synthesizing a robust controller is considered for a large, flexible space-based antenna by using the linear-quadratic-Gaussian (LQG)/loop transfer recovery (LTR) method. The study is based on a finite-element model of the 122-m hoop/column antenna, which consists of three rigid-body rotational modes and the first 10 elastic modes. A robust compensator design for achieving the required performance bandwidth in the presence of modeling uncertainties is obtained using the LQG/LTR method for loop-shaping in the frequency domain. Different sensor actuator locations are analyzed in terms of the pole/zero locations of the multivariable systems and possible best locations are indicated. The computations are performed by using the LQG design package ORACLS augmented with frequency domain singular value analysis software.

Teaching Database Design with Constraint-Based Tutors

ERIC Educational Resources Information Center

Mitrovic, Antonija; Suraweera, Pramuditha

2016-01-01

Design tasks are difficult to teach, due to large, unstructured solution spaces, underspecified problems, non-existent problem solving algorithms and stopping criteria. In this paper, we comment on our approach to develop KERMIT, a constraint-based tutor that taught database design. In later work, we re-implemented KERMIT as EER-Tutor, and…

Active large structures

NASA Technical Reports Server (NTRS)

Soosaar, K.

1982-01-01

Some performance requirements and development needs for the design of large space structures are described. Areas of study include: (1) dynamic response of large space structures; (2) structural control and systems integration; (3) attitude control; and (4) large optics and flexibility. Reference is made to a large space telescope.

Experimental Evaluation of the "Polished Panel Optical Receiver" Concept on the Deep Space Network's 34 Meter Antenna

NASA Technical Reports Server (NTRS)

Vilnrotter, Victor A.

2012-01-01

The potential development of large aperture ground-based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation proposes to polish the aluminum reflector panels of 34-meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by even state-of-the-art polished aluminum panels. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. A custom designed aluminum panel has been mounted on the 34 meter research antenna at Deep-Space Station 13 (DSS-13), and a remotely controlled CCD camera with a large CCD sensor in a weather-proof container has been installed next to the subreflector, pointed directly at the custom polished panel. Using the planet Jupiter as the optical point-source, the point-spread function (PSF) generated by the polished panel has been characterized, the array data processed to determine the center of the intensity distribution, and expected communications performance of the proposed polished panel optical receiver has been evaluated.

International manned lunar base - Beginning the 21st century in space

NASA Astrophysics Data System (ADS)

Smith, Harlan J.; Gurshtejn, Aleksandr A.; Mendell, Wendell

An evaluation is made of requirements for, and advantages in, the creation of a manned lunar base whose functions emphasize astronomical investigations. These astronomical studies would be able to capitalize on the lunar environment's ultrahigh vacuum, highly stable surface, dark and cold sky, low-G, absence of wind, isolation from terrestrial 'noise', locally usable ceramic raw materials, and large radiotelescope dish-supporting hemispherical craters. Large telescope structures would be nearly free of the gravity and wind loads that complicate their design on earth.

Cross-indexing of binary SIFT codes for large-scale image search.

PubMed

Liu, Zhen; Li, Houqiang; Zhang, Liyan; Zhou, Wengang; Tian, Qi

2014-05-01

In recent years, there has been growing interest in mapping visual features into compact binary codes for applications on large-scale image collections. Encoding high-dimensional data as compact binary codes reduces the memory cost for storage. Besides, it benefits the computational efficiency since the computation of similarity can be efficiently measured by Hamming distance. In this paper, we propose a novel flexible scale invariant feature transform (SIFT) binarization (FSB) algorithm for large-scale image search. The FSB algorithm explores the magnitude patterns of SIFT descriptor. It is unsupervised and the generated binary codes are demonstrated to be dispreserving. Besides, we propose a new searching strategy to find target features based on the cross-indexing in the binary SIFT space and original SIFT space. We evaluate our approach on two publicly released data sets. The experiments on large-scale partial duplicate image retrieval system demonstrate the effectiveness and efficiency of the proposed algorithm.

Large aperture and wide field of view space telescope for the detection of ultra high energy cosmic rays and neutrinos

NASA Astrophysics Data System (ADS)

Mazzinghi, Piero; Bratina, Vojko; Gambicorti, Lisa; Simonetti, Francesca; Zuccaro Marchi, Alessandro

2017-11-01

New technologies are proposed for large aperture and wide Field of View (FOV) space telescopes dedicated to detection of Ultra High Energy Cosmic Rays and Neutrinos flux, through observation of fluorescence traces in atmosphere and diffused Cerenkov signals. The presented advanced detection system is a spaceborne LEO telescope, with better performance than ground-based observatories, detecting up to 103 - 104 events/year. Different design approaches are implemented, all with very large FOV and focal surface detectors with sufficient segmentation and time resolution to allow precise reconstructions of the arrival direction. In particular, two Schmidt cameras are suggested as an appropriate solution to match most of the optical and technical requirements: large FOV, low f/#, reduction of stray light, optionally flat focal surface, already proven low-cost construction technologies. Finally, a preliminary proposal of a wideFOV retrofocus catadioptric telescope is explained.

Feasibility of a 30-meter space based laser transmitter

NASA Technical Reports Server (NTRS)

Berggren, R. R.; Lenertz, G. E.

1975-01-01

A study was made of the application of large expandable mirror structures in future space missions to establish the feasibility and define the potential of high power laser systems for such applications as propulsion and power transmission. Application of these concepts requires a 30-meter diameter, diffraction limited mirror for transmission of the laser energy. Three concepts for the transmitter are presented. These concepts include consideration of continuous as well as segmented mirror surfaces and the major stow-deployment categories of inflatable, variable geometry and assembled-in-space structures. The mirror surface for each concept would be actively monitored and controlled to maintain diffraction limited performance at 10.6 microns during operation. The proposed mirror configurations are based on existing aerospace state-of-the-art technology. The assembled-in-space concept appears to be the most feasible, at this time.

Effect of damping on excitability of high-order normal modes. [for a large space telescope spacecraft

NASA Technical Reports Server (NTRS)

Merchant, D. H.; Gates, R. M.; Straayer, J. W.

1975-01-01

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs.

Space resources. Volume 4: Social concerns

NASA Technical Reports Server (NTRS)

Mckay, Mary Fae (Editor); Mckay, David S. (Editor); Duke, Michael B. (Editor)

1992-01-01

Space resources must be used to support life on the Moon and exploration of Mars. This volume, Social Concerns, covers some of the most important issues which must be addressed in any major program for the human exploration of space. The volume begins with a consideration of the economics and management of large scale space activities. Then the legal aspects of these activities are discussed, particularly the interpretation of treaty law with respect to the Moon and asteroids. The social and cultural issues of moving people into space are considered in detail, and the eventual emergence of a space culture different from the existing culture is envisioned. The environmental issues raised by the development of space settlements are faced. Some innovative approaches are proposed to space communities and habitats and self-sufficiency is considered along with human safety at a lunar base or outpost.

Mitigating Aviation Communication and Satellite Orbit Operations Surprises from Adverse Space Weather

NASA Technical Reports Server (NTRS)

Tobiska, W. Kent

2008-01-01

Adverse space weather affects operational activities in aviation and satellite systems. For example, large solar flares create highly variable enhanced neutral atmosphere and ionosphere electron density regions. These regions impact aviation communication frequencies as well as precision orbit determination. The natural space environment, with its dynamic space weather variability, is additionally changed by human activity. The increase in orbital debris in low Earth orbit (LEO), combined with lower atmosphere CO2 that rises into the lower thermosphere and causes increased cooling that results in increased debris lifetime, adds to the environmental hazards of navigating in near-Earth space. This is at a time when commercial space endeavors are posed to begin more missions to LEO during the rise of the solar activity cycle toward the next maximum (2012). For satellite and aviation operators, adverse space weather results in greater expenses for orbit management, more communication outages or aviation and ground-based high frequency radio used, and an inability to effectively plan missions or service customers with space-based communication, imagery, and data transferal during time-critical activities. Examples of some revenue-impacting conditions and solutions for mitigating adverse space weather are offered.

Role of Sports Facilities in the Process of Revitalization of Brownfields

NASA Astrophysics Data System (ADS)

Taraszkiewicz, Karolina; Nyka, Lucyna

2017-10-01

The paper gives an evidence that building a large sports facility can generate beneficial urban space transformation and a significant improvement in the dilapidated urban areas. On the basis of theoretical investigations and case studies it can be proved that sports facilities introduced to urban brownfields could be considered one of the best known large scale revitalization methods. Large urban spaces surrounding sport facilities such as stadiums and other sports arenas create excellent conditions for designing additional recreational function, such as parks and other green areas. Since sports venues are very often located on brownfields and post-industrial spaces, there are usually well related with canals, rivers and other water routes or reservoirs. Such spaces become attractors for large groups of people. This, in effect initiate the process of introducing housing estates to the area and gradually the development of multifunctional urban structure. As research shows such process of favourable urban transformation could be based on implementing several important preconditions. One of the most significant one is the formation of the new communication infrastructure, which links newly formed territories with the well-structured urban core. Well planned program of the new sports facilities is also a very important factor. As research shows multifunctional large sports venues may function in the city as a new kind of public space that stimulates new genres of social relations, offers entertainment and free time activities, not necessarily related with sport. This finally leads to the creation of new jobs and more general improvement of a widely understood image of the district, growing appreciation for the emerging new location and consequently new investments in the neighbouring areas. The research gives new evidence to the ongoing discussion on the drawbacks and benefits of placing stadiums and sports arenas in the urban core.

Polymer space-charge-limited transistor as a solid-state vacuum tube triode

NASA Astrophysics Data System (ADS)

Chao, Yu-Chiang; Ku, Ming-Che; Tsai, Wu-Wei; Zan, Hsiao-Wen; Meng, Hsin-Fei; Tsai, Hung-Kuo; Horng, Sheng-Fu

2010-11-01

We report the construction of a polymer space-charge-limited transistor (SCLT), a solid-state version of vacuum tube triode. The SCLT achieves a high on/off ratio of 3×105 at a low operation voltage of 1.5 V by using high quality insulators both above and below the grid base electrode. Applying a greater bias to the base increases the barrier potential, and turns off the channel current, without introducing a large parasitic leakage current. Simulation result verifies the influence of base bias on channel potential distribution. The output current density is 1.7 mA/cm2 with current gain greater than 1000.

Decentralized control of large flexible structures by joint decoupling

NASA Technical Reports Server (NTRS)

Su, Tzu-Jeng; Juang, Jer-Nan

1992-01-01

A decentralized control design method is presented for large complex flexible structures by using the idea of joint decoupling. The derivation is based on a coupled substructure state-space model, which is obtained from enforcing conditions of interface compatibility and equilibrium to the substructure state-space models. It is shown that by restricting the control law to be localized state feedback and by setting the joint actuator input commands to decouple joint 'degrees of freedom' (dof) from interior dof, the global structure control design problem can be decomposed into several substructure control design problems. The substructure control gains and substructure observers are designed based on modified substructure state-space models. The controllers produced by the proposed method can operate successfully at the individual substructure level as well as at the global structure level. Therefore, not only control design but also control implementation is decentralized. Stability and performance requirement of the closed-loop system can be achieved by using any existing state feedback control design method. A two-component mass-spring damper system and a three-truss structure are used as examples to demonstrate the proposed method.

Construction of CASCI-type wave functions for very large active spaces.

PubMed

Boguslawski, Katharina; Marti, Konrad H; Reiher, Markus

2011-06-14

We present a procedure to construct a configuration-interaction expansion containing arbitrary excitations from an underlying full-configuration-interaction-type wave function defined for a very large active space. Our procedure is based on the density-matrix renormalization group (DMRG) algorithm that provides the necessary information in terms of the eigenstates of the reduced density matrices to calculate the coefficient of any basis state in the many-particle Hilbert space. Since the dimension of the Hilbert space scales binomially with the size of the active space, a sophisticated Monte Carlo sampling routine is employed. This sampling algorithm can also construct such configuration-interaction-type wave functions from any other type of tensor network states. The configuration-interaction information obtained serves several purposes. It yields a qualitatively correct description of the molecule's electronic structure, it allows us to analyze DMRG wave functions converged for the same molecular system but with different parameter sets (e.g., different numbers of active-system (block) states), and it can be considered a balanced reference for the application of a subsequent standard multi-reference configuration-interaction method.

Robust watermarking scheme for binary images using a slice-based large-cluster algorithm with a Hamming Code

NASA Astrophysics Data System (ADS)

Chen, Wen-Yuan; Liu, Chen-Chung

2006-01-01

The problems with binary watermarking schemes are that they have only a small amount of embeddable space and are not robust enough. We develop a slice-based large-cluster algorithm (SBLCA) to construct a robust watermarking scheme for binary images. In SBLCA, a small-amount cluster selection (SACS) strategy is used to search for a feasible slice in a large-cluster flappable-pixel decision (LCFPD) method, which is used to search for the best location for concealing a secret bit from a selected slice. This method has four major advantages over the others: (a) SBLCA has a simple and effective decision function to select appropriate concealment locations, (b) SBLCA utilizes a blind watermarking scheme without the original image in the watermark extracting process, (c) SBLCA uses slice-based shuffling capability to transfer the regular image into a hash state without remembering the state before shuffling, and finally, (d) SBLCA has enough embeddable space that every 64 pixels could accommodate a secret bit of the binary image. Furthermore, empirical results on test images reveal that our approach is a robust watermarking scheme for binary images.

DESTINY, The Dark Energy Space Telescope

NASA Technical Reports Server (NTRS)

Pasquale, Bert A.; Woodruff, Robert A.; Benford, Dominic J.; Lauer, Tod

2007-01-01

We have proposed the development of a low-cost space telescope, Destiny, as a concept for the NASA/DOE Joint Dark Energy Mission. Destiny is a 1.65m space telescope, featuring a near-infrared (0.85-1.7m) survey camera/spectrometer with a moderate flat-field field of view (FOV). Destiny will probe the properties of dark energy by obtaining a Hubble diagram based on Type Ia supernovae and a large-scale mass power spectrum derived from weak lensing distortions of field galaxies as a function of redshift.

Seminar presentation on the economic evaluation of the space shuttle system

NASA Technical Reports Server (NTRS)

1973-01-01

The proceedings of a seminar on the economic aspects of the space shuttle system are presented. Emphasis was placed on the problems of economic analysis of large scale public investments, the state of the art of cost estimation, the statistical data base for estimating costs of new technological systems, and the role of the main economic parameters affecting the results of the analyses. An explanation of the system components of a space program and the present choice of launch vehicles, spacecraft, and instruments was conducted.

Pre-Launch Risk Reduction Activities Conducted at KSC for the International Space Station

NASA Technical Reports Server (NTRS)

Kirkpatrick, Paul

2011-01-01

In the development of any large scale space-based multi-piece assembly effort, planning must include provisions for testing and verification; not only of the individual pieces but also of the pieces together. Without such testing on the ground, the risk to cost, schedule and technical performance increases substantially. This paper will review the efforts undertaken by the International Space Station (ISS), including the International Partners, during the pre-launch phase, primarily at KSC, to reduce the risks associated with the on-orbit assembly and operation of the ISS.

Policy model for space economy infrastructure

NASA Astrophysics Data System (ADS)

Komerath, Narayanan; Nally, James; Zilin Tang, Elizabeth

2007-12-01

Extraterrestrial infrastructure is key to the development of a space economy. Means for accelerating transition from today's isolated projects to a broad-based economy are considered. A large system integration approach is proposed. The beginnings of an economic simulation model are presented, along with examples of how interactions and coordination bring down costs. A global organization focused on space infrastructure and economic expansion is proposed to plan, coordinate, fund and implement infrastructure construction. This entity also opens a way to raise low-cost capital and solve the legal and public policy issues of access to extraterrestrial resources.

Possible LISA Technology Applications for Other Missions

NASA Technical Reports Server (NTRS)

Livas, Jeffrey

2018-01-01

The Laser Interferometer Space Antenna (LISA) has been selected as the third large class mission launch opportunity of the Cosmic Visions Program by the European Space Agency (ESA). LISA science will explore a rich spectrum of astrophysical gravitational-wave sources expected at frequencies between 0.0001 and 0.1 Hz and complement the work of other observatories and missions, both space and ground-based, electromagnetic and non-electromagnetic. Similarly, LISA technology may find applications for other missions. This paper will describe the capabilities of some of the key technologies and discuss possible contributions to other missions.

Why advanced computing? The key to space-based operations

NASA Astrophysics Data System (ADS)

Phister, Paul W., Jr.; Plonisch, Igor; Mineo, Jack

2000-11-01

The 'what is the requirement?' aspect of advanced computing and how it relates to and supports Air Force space-based operations is a key issue. In support of the Air Force Space Command's five major mission areas (space control, force enhancement, force applications, space support and mission support), two-fifths of the requirements have associated stringent computing/size implications. The Air Force Research Laboratory's 'migration to space' concept will eventually shift Science and Technology (S&T) dollars from predominantly airborne systems to airborne-and-space related S&T areas. One challenging 'space' area is in the development of sophisticated on-board computing processes for the next generation smaller, cheaper satellite systems. These new space systems (called microsats or nanosats) could be as small as a softball, yet perform functions that are currently being done by large, vulnerable ground-based assets. The Joint Battlespace Infosphere (JBI) concept will be used to manage the overall process of space applications coupled with advancements in computing. The JBI can be defined as a globally interoperable information 'space' which aggregates, integrates, fuses, and intelligently disseminates all relevant battlespace knowledge to support effective decision-making at all echelons of a Joint Task Force (JTF). This paper explores a single theme -- on-board processing is the best avenue to take advantage of advancements in high-performance computing, high-density memories, communications, and re-programmable architecture technologies. The goal is to break away from 'no changes after launch' design to a more flexible design environment that can take advantage of changing space requirements and needs while the space vehicle is 'on orbit.'

Spectral Radiance of a Large-Area Integrating Sphere Source

PubMed Central

Walker, James H.; Thompson, Ambler

1995-01-01

The radiance and irradiance calibration of large field-of-view scanning and imaging radiometers for remote sensing and surveillance applications has resulted in the development of novel calibration techniques. One of these techniques is the employment of large-area integrating sphere sources as radiance or irradiance secondary standards. To assist the National Aeronautical and Space Administration’s space based ozone measurement program, a commercially available large-area internally illuminated integrating sphere source’s spectral radiance was characterized in the wavelength region from 230 nm to 400 nm at the National Institute of Standards and Technology. Spectral radiance determinations and spatial mappings of the source indicate that carefully designed large-area integrating sphere sources can be measured with a 1 % to 2 % expanded uncertainty (two standard deviation estimate) in the near ultraviolet with spatial nonuniformities of 0.6 % or smaller across a 20 cm diameter exit aperture. A method is proposed for the calculation of the final radiance uncertainties of the source which includes the field of view of the instrument being calibrated. PMID:29151725

Toward large space systems. [Space Construction Base development from shuttles

NASA Technical Reports Server (NTRS)

Daros, C. J.; Freitag, R. F.; Kline, R. L.

1977-01-01

The design of the Space Transportation System, consisting of the Space Shuttle, Spacelab, and upper stages, provides experience for the development of more advanced space systems. The next stage will involve space stations in low earth orbit with limited self-sufficiency, characterized by closed ecological environments, space-generated power, and perhaps the first use of space materials. The third phase would include manned geosynchronous space-station activity and a return to lunar operations. Easier access to space will encourage the use of more complex, maintenance-requiring satellites than those currently used. More advanced space systems could perform a wide range of public services such as electronic mail, personal and police communication, disaster control, earthquake detection/prediction, water availability indication, vehicle speed control, and burglar alarm/intrusion detection. Certain products, including integrated-circuit chips and some enzymes, can be processed to a higher degree of purity in space and might eventually be manufactured there. Hardware including dishes, booms, and planar surfaces necessary for advanced space systems and their development are discussed.

Non-orthogonal internally contracted multi-configurational perturbation theory (NICPT): Dynamic electron correlation for large, compact active spaces

NASA Astrophysics Data System (ADS)

Kähler, Sven; Olsen, Jeppe

2017-11-01

A computational method is presented for systems that require high-level treatments of static and dynamic electron correlation but cannot be treated using conventional complete active space self-consistent field-based methods due to the required size of the active space. Our method introduces an efficient algorithm for perturbative dynamic correlation corrections for compact non-orthogonal MCSCF calculations. In the algorithm, biorthonormal expansions of orbitals and CI-wave functions are used to reduce the scaling of the performance determining step from quadratic to linear in the number of configurations. We describe a hierarchy of configuration spaces that can be chosen for the active space. Potential curves for the nitrogen molecule and the chromium dimer are compared for different configuration spaces. Already the most compact spaces yield qualitatively correct potentials that with increasing size of configuration spaces systematically approach complete active space results.

Effect of normalized plasma frequency on electron phase-space orbits in a free-electron laser

NASA Astrophysics Data System (ADS)

Ji, Yu-Pin; Wang, Shi-Jian; Xu, Jing-Yue; Xu, Yong-Gen; Liu, Xiao-Xu; Lu, Hong; Huang, Xiao-Li; Zhang, Shi-Chang

2014-02-01

Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser (FEL). In previous literature, it was demonstrated that the irregularity of the electron phase-space orbits could be caused in several ways, such as varying the wiggler amplitude and inducing sidebands. Based on a Hamiltonian model with a set of self-consistent differential equations, it is shown in this paper that the electron-beam normalized plasma frequency functions not only couple the electron motion with the FEL wave, which results in the evolution of the FEL wave field and a possible power saturation at a large beam current, but also cause the irregularity of the electron phase-space orbits when the normalized plasma frequency has a sufficiently large value, even if the initial energy of the electron is equal to the synchronous energy or the FEL wave does not reach power saturation.

Design of shape memory alloy actuated intelligent parabolic antenna for space applications

NASA Astrophysics Data System (ADS)

Kalra, Sahil; Bhattacharya, Bishakh; Munjal, B. S.

2017-09-01

The deployment of large flexible antennas is becoming critical for space applications today. Such antenna systems can be reconfigured in space for variable antenna footprint, and hence can be utilized for signal transmission to different geographic locations. Due to quasi-static shape change requirements, coupled with the demand of large deflection, shape memory alloy (SMA) based actuators are uniquely suitable for this system. In this paper, we discuss the design and development of a reconfigurable parabolic antenna structure. The reflector skin of the antenna is vacuum formed using a metalized polycarbonate shell. Two different strategies are chosen for the antenna actuation. Initially, an SMA wire based offset network is formed on the back side of the reflector. A computational model is developed using equivalent coefficient of thermal expansion (ECTE) for the SMA wire. Subsequently, the interaction between the antenna and SMA wire is modeled as a constrained recovery system, using a 1D modified Brinson model. Joule effect based SMA phase transformation is considered for the relationship between input voltage and temperature at the SMA wire. The antenna is modeled using ABAQUS based finite element methodology. The deflection found through the computational model is compared with that measured in experiment. Subsequently, a point-wise actuation system is developed for higher deflection. For power-minimization, an auto-locking device is developed. The performance of the new configuration is compared with the offset-network configuration. It is envisaged that the study will provide a comprehensive procedure for the design of intelligent flexible structures especially suitable for space applications.

The scientific data acquisition system of the GAMMA-400 space project

NASA Astrophysics Data System (ADS)

Bobkov, S. G.; Serdin, O. V.; Gorbunov, M. S.; Arkhangelskiy, A. I.; Topchiev, N. P.

2016-02-01

The description of scientific data acquisition system (SDAS) designed by SRISA for the GAMMA-400 space project is presented. We consider the problem of different level electronics unification: the set of reliable fault-tolerant integrated circuits fabricated on Silicon-on-Insulator 0.25 mkm CMOS technology and the high-speed interfaces and reliable modules used in the space instruments. The characteristics of reliable fault-tolerant very large scale integration (VLSI) technology designed by SRISA for the developing of computation systems for space applications are considered. The scalable net structure of SDAS based on Serial RapidIO interface including real-time operating system BAGET is described too.

Space-multiplexed optical scanner.

PubMed

Riza, Nabeel A; Yaqoob, Zahid

2004-05-01

A low-loss two-dimensional optical beam scanner that is capable of delivering large (e.g., > 10 degrees) angular scans along the elevation as well as the azimuthal direction is presented. The proposed scanner is based on a space-switched parallel-serial architecture that employs a coarse-scanner module and a fine-scanner module that produce an ultrahigh scan space-fill factor, e.g., 900 x 900 distinguishable beams in a 10 degrees (elevation) x 10 degrees (azimuth) scan space. The experimentally demonstrated one-dimensional version of the proposed scanner has a supercontinuous scan, 100 distinguishable beam spots in a 2.29 degrees total scan range, and 1.5-dB optical insertion loss.

Design and implementation of robust decentralized control laws for the ACES structure at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Collins, Emmanuel G., Jr.; Phillips, Douglas J.; Hyland, David C.

1990-01-01

Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line-of-sight accuracy. In order for these concepts to become operational it is imperative that the benefits of active vibration control be practically demonstrated in ground based experiments. The results of the experiment successfully demonstrate active vibration control for a flexible structure. The testbed is the Active Control Technique Evaluation for Spacecraft (ACES) structure at NASA Marshall Space Flight Center. The ACES structure is dynamically traceable to future space systems and especially allows the study of line-of-sight control issues.

Performance-Based Seismic Retrofit of Soft-Story Woodframe Buildings

Treesearch

P. Bahmani; J.W. van de Lindt; S.E. Pryor; G.L. Mochizuki; M. Gershfeld; D. Rammer; J. Tian; D. Symans

2013-01-01

Soft-story woodframe buildings are recognizable by their large garage openings at the bottom story which are typically for parking and storage. In soft-story buildings the relative stiffness and strength of the soft-story, usually the bottom story, is significantly less than the upper stories due to the presence of large openings which reduce the available space for...

VisIRR: A Visual Analytics System for Information Retrieval and Recommendation for Large-Scale Document Data

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

Choo, Jaegul; Kim, Hannah; Clarkson, Edward

In this paper, we present an interactive visual information retrieval and recommendation system, called VisIRR, for large-scale document discovery. VisIRR effectively combines the paradigms of (1) a passive pull through query processes for retrieval and (2) an active push that recommends items of potential interest to users based on their preferences. Equipped with an efficient dynamic query interface against a large-scale corpus, VisIRR organizes the retrieved documents into high-level topics and visualizes them in a 2D space, representing the relationships among the topics along with their keyword summary. In addition, based on interactive personalized preference feedback with regard to documents,more » VisIRR provides document recommendations from the entire corpus, which are beyond the retrieved sets. Such recommended documents are visualized in the same space as the retrieved documents, so that users can seamlessly analyze both existing and newly recommended ones. This article presents novel computational methods, which make these integrated representations and fast interactions possible for a large-scale document corpus. We illustrate how the system works by providing detailed usage scenarios. Finally, we present preliminary user study results for evaluating the effectiveness of the system.« less

VisIRR: A Visual Analytics System for Information Retrieval and Recommendation for Large-Scale Document Data

DOE PAGES

Choo, Jaegul; Kim, Hannah; Clarkson, Edward; ...

2018-01-31

In this paper, we present an interactive visual information retrieval and recommendation system, called VisIRR, for large-scale document discovery. VisIRR effectively combines the paradigms of (1) a passive pull through query processes for retrieval and (2) an active push that recommends items of potential interest to users based on their preferences. Equipped with an efficient dynamic query interface against a large-scale corpus, VisIRR organizes the retrieved documents into high-level topics and visualizes them in a 2D space, representing the relationships among the topics along with their keyword summary. In addition, based on interactive personalized preference feedback with regard to documents,more » VisIRR provides document recommendations from the entire corpus, which are beyond the retrieved sets. Such recommended documents are visualized in the same space as the retrieved documents, so that users can seamlessly analyze both existing and newly recommended ones. This article presents novel computational methods, which make these integrated representations and fast interactions possible for a large-scale document corpus. We illustrate how the system works by providing detailed usage scenarios. Finally, we present preliminary user study results for evaluating the effectiveness of the system.« less

Performance/price estimates for cortex-scale hardware: a design space exploration.

PubMed

Zaveri, Mazad S; Hammerstrom, Dan

2011-04-01

In this paper, we revisit the concept of virtualization. Virtualization is useful for understanding and investigating the performance/price and other trade-offs related to the hardware design space. Moreover, it is perhaps the most important aspect of a hardware design space exploration. Such a design space exploration is a necessary part of the study of hardware architectures for large-scale computational models for intelligent computing, including AI, Bayesian, bio-inspired and neural models. A methodical exploration is needed to identify potentially interesting regions in the design space, and to assess the relative performance/price points of these implementations. As an example, in this paper we investigate the performance/price of (digital and mixed-signal) CMOS and hypothetical CMOL (nanogrid) technology based hardware implementations of human cortex-scale spiking neural systems. Through this analysis, and the resulting performance/price points, we demonstrate, in general, the importance of virtualization, and of doing these kinds of design space explorations. The specific results suggest that hybrid nanotechnology such as CMOL is a promising candidate to implement very large-scale spiking neural systems, providing a more efficient utilization of the density and storage benefits of emerging nano-scale technologies. In general, we believe that the study of such hypothetical designs/architectures will guide the neuromorphic hardware community towards building large-scale systems, and help guide research trends in intelligent computing, and computer engineering. Copyright © 2010 Elsevier Ltd. All rights reserved.

Conference Proceedings of NASA/DoD Controls-Structures Interaction Technology Held in San Diego, California on 29 January-2 February 1989,

DTIC Science & Technology

1989-08-01

NASA Langley Research Center, Hampton, Virginia, and Wright Research Development Center, Wright-Patterson Air Force Base, Ohio, and held in San Diego...427 Shalom Fisher SPACE TRUSS ZERO GRAVITY DYNAMICS. ............................... 445 Captain Andy Swanson UNITED STATES AIR FORCE ACADEMY GET-AWAY...HOUSE EXPERIMENTS IN LARGE SPACE STRUCTURES AT THE AIR FORCE WRIGHT AERONAUTICAL LABORATORIES FLIGHT DYNAMICS LABORATORY

A ten-meter optical telescope for deep-space communications

NASA Technical Reports Server (NTRS)

Shaik, Kamran; Kerr, Edwin L.

1990-01-01

Optical communications using laser light in the visible spectral range is being considered for future deep-space missions. Such a system will require a large telescope in earth vicinity to be used as a receiving station for data return from the spacecraft. A preliminary discussion for a ground-based receiving station consisting of a 10-meter hexagonally segmented primary with high surface tolerance and a unique sunshade is presented.

Digital processing of mesoscale analysis and space sensor data

NASA Technical Reports Server (NTRS)

Hickey, J. S.; Karitani, S.

1985-01-01

The mesoscale analysis and space sensor (MASS) data management and analysis system on the research computer system is presented. The MASS data base management and analysis system was implemented on the research computer system which provides a wide range of capabilities for processing and displaying large volumes of conventional and satellite derived meteorological data. The research computer system consists of three primary computers (HP-1000F, Harris/6, and Perkin-Elmer 3250), each of which performs a specific function according to its unique capabilities. The overall tasks performed concerning the software, data base management and display capabilities of the research computer system in terms of providing a very effective interactive research tool for the digital processing of mesoscale analysis and space sensor data is described.

Agent Technology, Complex Adaptive Systems, and Autonomic Systems: Their Relationships

NASA Technical Reports Server (NTRS)

Truszkowski, Walt; Rash, James; Rouff, Chistopher; Hincheny, Mike

2004-01-01

To reduce the cost of future spaceflight missions and to perform new science, NASA has been investigating autonomous ground and space flight systems. These goals of cost reduction have been further complicated by nanosatellites for future science data-gathering which will have large communications delays and at times be out of contact with ground control for extended periods of time. This paper describes two prototype agent-based systems, the Lights-out Ground Operations System (LOGOS) and the Agent Concept Testbed (ACT), and their autonomic properties that were developed at NASA Goddard Space Flight Center (GSFC) to demonstrate autonomous operations of future space flight missions. The paper discusses the architecture of the two agent-based systems, operational scenarios of both, and the two systems autonomic properties.

Experimental evaluation of battery cells for space-based radar application

NASA Technical Reports Server (NTRS)

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

A test program was conducted to characterize five space-quality nickel-hydrogen (NiH2) battery cells. A subset of those tests was also done on five commercial nickel-cadmium (NiCd) cells, for correlation to the characteristics of an Energy Storage Unit Simulator. The test program implemented the recommendations of a 1991 study, as reported to IECEC-92. The findings of the tests are summarized, and expected impacts on the performance of the electrical power system (EPS) of a large space-based radar (SBR) surveillance satellite are derived. The main characteristics examined and compared were terminal voltage (average and transient) and capacity through discharge, equivalent series resistance, derived inductance and capacitance, charge return efficiency, and inter-pulse charge effectiveness.

Recommendations for Safe Separation Distances from the Kennedy Space Center (KSC) Vehicle Assembly Building (VAB) Using a Heat-Flux-Based Analytical Approach (Abridged)

NASA Technical Reports Server (NTRS)

Cragg, Clinton H.; Bowman, Howard; Wilson, John E.

2011-01-01

The NASA Engineering and Safety Center (NESC) was requested to provide computational modeling to support the establishment of a safe separation distance surrounding the Kennedy Space Center (KSC) Vehicle Assembly Building (VAB). The two major objectives of the study were 1) establish a methodology based on thermal flux to determine safe separation distances from the Kennedy Space Center's (KSC's) Vehicle Assembly Building (VAB) with large numbers of solid propellant boosters containing hazard division 1.3 classification propellants, in case of inadvertent ignition; and 2) apply this methodology to the consideration of housing eight 5-segment solid propellant boosters in the VAB. The results of the study are contained in this report.

High Thermal Conductivity Polymer Matrix Composites (PMC) for Advanced Space Radiators

NASA Technical Reports Server (NTRS)

Shin, E. Eugene; Bowman, Cheryl; Beach, Duane

2007-01-01

High temperature polymer matrix composites (PMC) reinforced with high thermal conductivity (approx. 1000 W/mK) pitch-based carbon fibers are evaluated for a facesheet/fin structure of large space radiator systems. Significant weight reductions along with improved thermal performance, structural integrity and space durability toward its metallic counterparts were envisioned. Candidate commercial resin systems including Cyanate Esters, BMIs, and polyimide were selected based on thermal capabilities and processability. PMC laminates were designed to match the thermal expansion coefficient of various metal heat pipes or tubes. Large, but thin composite panels were successfully fabricated after optimizing cure conditions. Space durability of PMC with potential degradation mechanisms was assessed by simulated thermal aging tests in high vacuum, 1-3 x 10(exp -6) torr, at three temperatures, 227 C, 277 C, and 316 C for up to one year. Nanocomposites with vapor-grown carbon nano-fibers and exfoliated graphite flakes were attempted to improve thermal conductivity (TC) and microcracking resistance. Good quality nanocomposites were fabricated and evaluated for TC and durability including radiation resistance. TC was measured in both in-plan and thru-the-thickness directions, and the effects of microcracks on TC are also being evaluated. This paper will discuss the systematic experimental approaches, various performance-durability evaluations, and current subcomponent design and fabrication/manufacturing efforts.

From Monolithics to Tethers to Freeflyers: The Spectrum of Large Aperture Sensing from Space

NASA Technical Reports Server (NTRS)

Leitner, Jesse; Quinn, David; Bauer, Frank (Technical Monitor)

2002-01-01

As part of NASA's endeavor to push the envelope and go where we have never been before, the Space Science Enterprise has laid out a vision which includes several missions that revolutionize the collection of scientific data from space. Many of the missions designed to meet the objectives of these programs depend heavily on the ability to perform space-based interferometry, which has recently become a rapidly growing field of investigation for both the scientific and engineering communities. While scientists are faced with the challenges of designing high fidelity optical systems capable of making detailed observations, engineers wrestle with the problem of providing s-pace-based platforms that can permit this data gathering to occur. Observational data gathering is desired at's variety of spectral wavelengths and resolutions, calling for interferometers with a range of baseline requirements. Approaches to configuration design are as varied as the missions themselves from large monolithic spacecraft to multiple free-flying small spacecraft and everything in between. As will be discussed, no one approach provides a 'panacea' of solutions rather each has its place in terms of the mission requirements. The purpose here is to identify the advantages and disadvantages of the various approaches, to discuss the driving factors in design selection and determine the relative range of applicability of each design approach.

An atomic orbital based real-time time-dependent density functional theory for computing electronic circular dichroism band spectra

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

Goings, Joshua J.; Li, Xiaosong, E-mail: xsli@uw.edu

2016-06-21

One of the challenges of interpreting electronic circular dichroism (ECD) band spectra is that different states may have different rotatory strength signs, determined by their absolute configuration. If the states are closely spaced and opposite in sign, observed transitions may be washed out by nearby states, unlike absorption spectra where transitions are always positive additive. To accurately compute ECD bands, it is necessary to compute a large number of excited states, which may be prohibitively costly if one uses the linear-response time-dependent density functional theory (TDDFT) framework. Here we implement a real-time, atomic-orbital based TDDFT method for computing the entiremore » ECD spectrum simultaneously. The method is advantageous for large systems with a high density of states. In contrast to previous implementations based on real-space grids, the method is variational, independent of nuclear orientation, and does not rely on pseudopotential approximations, making it suitable for computation of chiroptical properties well into the X-ray regime.« less

Controlling Surface Plasmons Through Covariant Transformation of the Spin-Dependent Geometric Phase Between Curved Metamaterials

NASA Astrophysics Data System (ADS)

Zhong, Fan; Li, Jensen; Liu, Hui; Zhu, Shining

2018-06-01

General relativity uses curved space-time to describe accelerating frames. The movement of particles in different curved space-times can be regarded as equivalent physical processes based on the covariant transformation between different frames. In this Letter, we use one-dimensional curved metamaterials to mimic accelerating particles in curved space-times. The different curved shapes of structures are used to mimic different accelerating frames. The different geometric phases along the structure are used to mimic different movements in the frame. Using the covariant principle of general relativity, we can obtain equivalent nanostructures based on space-time transformations, such as the Lorentz transformation and conformal transformation. In this way, many covariant structures can be found that produce the same surface plasmon fields when excited by spin photons. A new kind of accelerating beam, the Rindler beam, is obtained based on the Rindler metric in gravity. Very large effective indices can be obtained in such systems based on geometric-phase gradient. This general covariant design method can be extended to many other optical media.

Ionizing Radiation Environments and Exposure Risks

NASA Astrophysics Data System (ADS)

Kim, M. H. Y.

2015-12-01

Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) are simulated to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, near-Earth asteroid, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmospheres of Earth or Mars, space vehicle, and astronaut's body tissues using NASA's HZETRN/QMSFRG computer code. Space radiation protection methods, which are derived largely from ground-based methods recommended by the National Council on Radiation Protection and Measurements (NCRP) or International Commission on Radiological Protections (ICRP), are built on the principles of risk justification, limitation, and ALARA (as low as reasonably achievable). However, because of the large uncertainties in high charge and energy (HZE) particle radiobiology and the small population of space crews, NASA develops distinct methods to implement a space radiation protection program. For the fatal cancer risks, which have been considered the dominant risk for GCR, the NASA Space Cancer Risk (NSCR) model has been developed from recommendations by NCRP; and undergone external review by the National Research Council (NRC), NCRP, and through peer-review publications. The NSCR model uses GCR environmental models, particle transport codes describing the GCR modification by atomic and nuclear interactions in atmospheric shielding coupled with spacecraft and tissue shielding, and NASA-defined quality factors for solid cancer and leukemia risk estimates for HZE particles. By implementing the NSCR model, the exposure risks from various heliospheric conditions are assessed for the radiation environments for various-class mission types to understand architectures and strategies of human exploration missions and ultimately to contribute to the optimization of radiation safety and well-being of space crewmembers participating in long-term space missions.

Effect of the Axial Spacing between Vanes and Blades on a Transonic Gas Turbine Performance and Blade Loading

NASA Astrophysics Data System (ADS)

Chang, Dongil; Tavoularis, Stavros

2013-03-01

Unsteady numerical simulations have been conducted to investigate the effect of axial spacing between the stator vanes and the rotor blades on the performance of a transonic, single-stage, high-pressure, axial turbine. Three cases were considered, the normal case, which is based on the geometry of a commercial jet engine and has an axial spacing at 50% blade span equal to 42% of the vane axial chord, as well as two other cases with axial spacings equal to 31 and 52% vane axial chords, respectively. Present interest has focused on the effect of axial gap size on the instantaneous and time-averaged flows as well as on the blade loading and the turbine performance. Decreasing the gap size reduced the pressure and increased the Mach number in the core flows in the gap region. However, the flows near the two endwalls did not follow monotonic trends with the gap size change; instead, the Mach numbers for both the small gap and the large gap cases were lower than that for the normal case. This Mach number decrease was attributed to increased turbulence due to the increased wake strength for the small gap case and an increased wake width for the large gap case. In all considered cases, large pressure fluctuations were observed in the front region of the blade suction side. These pressure fluctuations were strongest for the smaller spacing. The turbine efficiencies of the cases with the larger and smaller spacings were essentially the same, but both were lower than that of the normal case. The stator loss for the smaller spacing case was lower than the one for the larger spacing case, whereas the opposite was true for the rotor loss.

Business innovation symposium ‘At what price? IP-related thoughts on new business models for space information’

NASA Astrophysics Data System (ADS)

Smith, Lesley Jane

2011-09-01

Spatial data and imagery generators are set to become tomorrow's key players in the information society. This is why satellite owners and operators are examining new revenue-producing models for developing space-related products and services. The use and availability of broadband internet width and satellite data-based services will continue to increase in the future. With the capacity to deliver real time precision downstream data, space agencies and the satellite industry can respond to the demand for high resolution digital space information which, with the appropriate technology, can be integrated into a variety of web-based applications. At a time when the traditional roles of space agencies are becoming more hybrid, largely as a result of the greater drive towards commercial markets, new value-added markets for space-related information products are continuing to attract attention. This paper discusses whether traditional data policies on space data access and IP licensing schemes stand to remain the feasible prototype for distributing and marketing space data, and how this growth market might benefit from looking at an 'up and running' global IP management system already operating to manage end user digital demand. PrefaceThe terminology describing the various types of spatial data and space-based information is not uniformly used within the various principles, laws and policies that govern space data. For convenience only this paper refers to primary or raw data gathered by the space-based industry as spatial or raw data, and the data as processed and sold on or distributed by ground-based companies as space information products and services. In practise, spatial data range from generic to specific data sets, digital topography, through to pictures and imagery services at various resolutions, with 3-D perspectives underway. The paper addresses general IP considerations relating to spatial data, with some reference to remote sensing itself. Exact IP details will depend at all times on the final product and service in question.

Can the United States afford a lunar base

NASA Technical Reports Server (NTRS)

Keaton, Paul W.

1988-01-01

Establishing a lunar base will require steady funding for a decade or two. The question addressed is whether such a large space project is affordable at this time. The relevant facts and methodology are presented so that the reader may formulate independent answers. It is shown that a permanent lunar base can be financed without increasing NASA's historical budgetary trend.

Model for large magnetoresistance effect in p–n junctions

NASA Astrophysics Data System (ADS)

Cao, Yang; Yang, Dezheng; Si, Mingsu; Shi, Huigang; Xue, Desheng

2018-06-01

We present a simple model based on the classic Shockley model to explain the magnetotransport in nonmagnetic p–n junctions. Under a magnetic field, the evaluation of the carrier to compensate Lorentz force establishes the necessary space-charge region distribution. The calculated current–voltage (I–V) characteristics under various magnetic fields demonstrate that the conventional nonmagnetic p–n junction can exhibit an extremely large magnetoresistance effect, which is even larger than that in magnetic materials. Because the large magnetoresistance effect that we discussed is based on the conventional p–n junction device, our model provides new insight into the development of semiconductor magnetoelectronics.

Large Space Systems Technology, Part 2, 1981

NASA Technical Reports Server (NTRS)

Boyer, W. J. (Compiler)

1982-01-01

Four major areas of interest are covered: technology pertinent to large antenna systems; technology related to the control of large space systems; basic technology concerning structures, materials, and analyses; and flight technology experiments. Large antenna systems and flight technology experiments are described. Design studies, structural testing results, and theoretical applications are presented with accompanying validation data. These research studies represent state-of-the art technology that is necessary for the development of large space systems. A total systems approach including structures, analyses, controls, and antennas is presented as a cohesive, programmatic plan for large space systems.

Biology relevant to space radiation

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

Fry, R J.M.

There are only very limited data on the health effects to humans from the two major components of the radiations in space, namely protons and heavy ions. As a result, predictions of the accompanying effects must be based either on (1) data generated through studies of experimental systems exposed on earth at rates and fluences higher than those in space, or (2) extrapolations from studies of gamma and x rays. Better information is needed about the doses, dose rates, and the energy and LET spectra of the radiations at the organ level that are anticipated to be encountered during extendedmore » space missions. In particular, there is a need for better estimates of the relationship between radiation quality and biological effects. In the case of deterministic effects, it is the threshold that is important. The possibility of the occurrence of a large solar particle event (SPE) requires that such effects be considered during extended space missions. Analyses suggest, however, that it is feasible to provide sufficient shielding so as to reduce such effects to acceptable levels, particularly if the dose rates can be limited. If these analyses prove correct, the primary biological risks will be the stochastic effects (latent cancer induction). The contribution of one large SPE to the risk of stochastic effects while undesirable will not be large in comparison to the potential total dose on a mission of long duration.« less

Expanding Hematoma's Life-Threatening Neck and Face Emergency Management of Ballistic Injuries.

PubMed

Shuker, Sabri T

2016-07-01

This article aims to bring attention to the morbidity and fatality of hemorrhage, how expanding hematoma and air compromise neck/face N/F injuries and present challenges. Large neck vessel ballistic injuries may lead to hemorrhage and expanding hematoma, resulting in airway compromise, due to injuries to the internal and/or external carotid arteries, internal jugular veins "internal carotid artery, external carotid artery, internal jugular vein," and the external carotid artery deep branches. This also leads to injuries to the cervical fascial layers (barriers of deep spaces) that facilitate pooling blood and hematoma into compartmental and large potential space which effects the pharynx, larynx, esophagus, and trachea.The expanding hematomas distort neck anatomical landmarks so "no neck zones" classifications are applicable. As the spectrum of injuries continues to evolve, the clinical characterization needs a new categorization based on compartmental hematoma and potential space anatomical location like retropharyngeal, parapharyngeal, sublingual, submandibular spaces, retrobulbar, and cheek compartment space hematomas.Presence of symptoms and location of the hematoma generally dictate what type of procedure is needed and how urgently it needs to be appropriately performed.Two unusual patients of pseudoaneurysms facial artery injuries with extravasation of blood producing a pulsating hematoma are referred to. Another patient considers large internal carotid artery injuries pseudoaneurysms revealed in angiography.The immediate management of life-saving patients requires aggressive airway maintenance at the scene, conscious victim will often obtain a posture that clears his airway and the semiconscious or unconscious put him in prone position. Air compromise may need emergency intubation, large bore cannula cricothyroidotomy, cricothyrotomy and at medical facilities tracheostomy.

Flame Spread and Group-Combustion Excitation in Randomly Distributed Droplet Clouds with Low-Volatility Fuel near the Excitation Limit: a Percolation Approach Based on Flame-Spread Characteristics in Microgravity

NASA Astrophysics Data System (ADS)

Mikami, Masato; Saputro, Herman; Seo, Takehiko; Oyagi, Hiroshi

2018-03-01

Stable operation of liquid-fueled combustors requires the group combustion of fuel spray. Our study employs a percolation approach to describe unsteady group-combustion excitation based on findings obtained from microgravity experiments on the flame spread of fuel droplets. We focus on droplet clouds distributed randomly in three-dimensional square lattices with a low-volatility fuel, such as n-decane in room-temperature air, where the pre-vaporization effect is negligible. We also focus on the flame spread in dilute droplet clouds near the group-combustion-excitation limit, where the droplet interactive effect is assumed negligible. The results show that the occurrence probability of group combustion sharply decreases with the increase in mean droplet spacing around a specific value, which is termed the critical mean droplet spacing. If the lattice size is at smallest about ten times as large as the flame-spread limit distance, the flame-spread characteristics are similar to those over an infinitely large cluster. The number density of unburned droplets remaining after completion of burning attained maximum around the critical mean droplet spacing. Therefore, the critical mean droplet spacing is a good index for stable combustion and unburned hydrocarbon. In the critical condition, the flame spreads through complicated paths, and thus the characteristic time scale of flame spread over droplet clouds has a very large value. The overall flame-spread rate of randomly distributed droplet clouds is almost the same as the flame-spread rate of a linear droplet array except over the flame-spread limit.

Economic effects and spin-offs in a small space economy: the case of Canada.

PubMed

Amesse, Fernand; Cohendet, Patrick; Poirier, Alain; Chouinard, Jean-Marc

2002-12-01

Canada, through a well-focused space program (telecommunications, earth observation, robotics), has succeeded in developing a space industry largely based on SMEs. The result has been significant economic benefits and technological spin-offs. In this article, the results of two programs, the ESA (European Space Agency) and the STEAR (Strategic Technologies in Automation and Robotics), are compared. The ESA program has generated significant indirect effects and spin-offs for Canadian exports. ESA's reputation and network have enabled SMEs to increase export sales of both space products and other commercial products derived from space technologies. The STEAR program has been highly successful in promoting a new generation of SMEs for space robotics, encouraging both spin-in and spin-offs of technologies. The analysis highlights the complementarity of mission- and diffusion-oriented programs in the technology transfer process.

PLAN-IT: Knowledge-Based Mission Sequencing

NASA Astrophysics Data System (ADS)

Biefeld, Eric W.

1987-02-01

Mission sequencing consumes a large amount of time and manpower during a space exploration effort. Plan-It is a knowledge-based approach to assist in mission sequencing. Plan-It uses a combined frame and blackboard architecture. This paper reports on the approach implemented by Plan-It and the current applications of Plan-It for sequencing at NASA.

Large space systems technology, 1980, volume 1

NASA Technical Reports Server (NTRS)

Kopriver, F., III (Compiler)

1981-01-01

The technological and developmental efforts in support of the large space systems technology are described. Three major areas of interests are emphasized: (1) technology pertient to large antenna systems; (2) technology related to large space systems; and (3) activities that support both antenna and platform systems.

Space Colonization Using Space-Elevators from Phobos

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M.

2003-01-01

A novel approach is examined for creating an industrial civilization beyond Earth. The approach would take advantage of the unique configuration of Mars and its moon Phobos to make a transportation system capable of raising mass from the surface of Mars to space at a low cost. Mars would be used as the primary location for support personnel and infrastructure. Phobos would be used as a source of raw materials for space-based activity, and as an anchor for tethered carbon-nanotube-based space-elevators. One space-elevator would terminate at the upper edge of Mars' atmosphere. Small craft would be launched from Mars' surface to rendezvous with the moving elevator tip and their payloads detached and raised with solar powered loop elevators to Phobos. Another space-elevator would be extended outward from Phobos to launch craft toward the Earth/Moon system or the asteroid belt. The outward tip would also be used to catch arriving craft. This approach would allow Mars to be colonized, and allow transportation of people and supplies from Mars to support the space industry. In addition, large quantities of material obtained from Phobos could be used to construct space habitats and also supply propellant and material for space industry in the Earth/Moon system as well as around Mars.

The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Galaxy clustering and redshift-space distortions at z ≃ 0.8 in the first data release

NASA Astrophysics Data System (ADS)

de la Torre, S.; Guzzo, L.; Peacock, J. A.; Branchini, E.; Iovino, A.; Granett, B. R.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Moscardini, L.; Paioro, L.; Percival, W. J.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Monaco, P.; Nichol, R. C.; Phleps, S.; Wolk, M.; Zamorani, G.

2013-09-01

We present the general real- and redshift-space clustering properties of galaxies as measured in the first data release of the VIPERS survey. VIPERS is a large redshift survey designed to probe in detail the distant Universe and its large-scale structure at 0.5 < z < 1.2. We describe in this analysis the global properties of the sample and discuss the survey completeness and associated corrections. This sample allows us to measure the galaxy clustering with an unprecedented accuracy at these redshifts. From the redshift-space distortions observed in the galaxy clustering pattern we provide a first measurement of the growth rate of structure at z = 0.8: fσ8 = 0.47 ± 0.08. This is completely consistent with the predictions of standard cosmological models based on Einstein gravity, although this measurement alone does not discriminate between different gravity models. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

Laboratory simulation of space plasma phenomena*

NASA Astrophysics Data System (ADS)

Amatucci, B.; Tejero, E. M.; Ganguli, G.; Blackwell, D.; Enloe, C. L.; Gillman, E.; Walker, D.; Gatling, G.

2017-12-01

Laboratory devices, such as the Naval Research Laboratory's Space Physics Simulation Chamber, are large-scale experiments dedicated to the creation of large-volume plasmas with parameters realistically scaled to those found in various regions of the near-Earth space plasma environment. Such devices make valuable contributions to the understanding of space plasmas by investigating phenomena under carefully controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. By working in collaboration with in situ experimentalists to create realistic conditions scaled to those found during the observations of interest, the microphysics responsible for the observed events can be investigated in detail not possible in space. To date, numerous investigations of phenomena such as plasma waves, wave-particle interactions, and particle energization have been successfully performed in the laboratory. In addition to investigations such as plasma wave and instability studies, the laboratory devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this presentation, we will describe several examples of the laboratory investigation of space plasma waves and instabilities and diagnostic development. *This work supported by the NRL Base Program.

Comparative Performance in Single-Port Versus Multiport Minimally Invasive Surgery, and Small Versus Large Operative Working Spaces

PubMed Central

Marcus, Hani J.; Seneci, Carlo A.; Hughes-Hallett, Archie; Cundy, Thomas P.; Nandi, Dipankar; Yang, Guang-Zhong; Darzi, Ara

2015-01-01

Background. Surgical approaches such as transanal endoscopic microsurgery, which utilize small operative working spaces, and are necessarily single-port, are particularly demanding with standard instruments and have not been widely adopted. The aim of this study was to compare simultaneously surgical performance in single-port versus multiport approaches, and small versus large working spaces. Methods. Ten novice, 4 intermediate, and 1 expert surgeons were recruited from a university hospital. A preclinical randomized crossover study design was implemented, comparing performance under the following conditions: (1) multiport approach and large working space, (2) multiport approach and intermediate working space, (3) single-port approach and large working space, (4) single-port approach and intermediate working space, and (5) single-port approach and small working space. In each case, participants performed a peg transfer and pattern cutting tasks, and each task repetition was scored. Results. Intermediate and expert surgeons performed significantly better than novices in all conditions (P < .05). Performance in single-port surgery was significantly worse than multiport surgery (P < .01). In multiport surgery, there was a nonsignificant trend toward worsened performance in the intermediate versus large working space. In single-port surgery, there was a converse trend; performances in the intermediate and small working spaces were significantly better than in the large working space. Conclusions. Single-port approaches were significantly more technically challenging than multiport approaches, possibly reflecting loss of instrument triangulation. Surprisingly, in single-port approaches, in which triangulation was no longer a factor, performance in large working spaces was worse than in intermediate and small working spaces. PMID:26464468

Efficient design of nanoplasmonic waveguide devices using the space mapping algorithm.

PubMed

Dastmalchi, Pouya; Veronis, Georgios

2013-12-30

We show that the space mapping algorithm, originally developed for microwave circuit optimization, can enable the efficient design of nanoplasmonic waveguide devices which satisfy a set of desired specifications. Space mapping utilizes a physics-based coarse model to approximate a fine model accurately describing a device. Here the fine model is a full-wave finite-difference frequency-domain (FDFD) simulation of the device, while the coarse model is based on transmission line theory. We demonstrate that simply optimizing the transmission line model of the device is not enough to obtain a device which satisfies all the required design specifications. On the other hand, when the iterative space mapping algorithm is used, it converges fast to a design which meets all the specifications. In addition, full-wave FDFD simulations of only a few candidate structures are required before the iterative process is terminated. Use of the space mapping algorithm therefore results in large reductions in the required computation time when compared to any direct optimization method of the fine FDFD model.

2D data-space cross-gradient joint inversion of MT, gravity and magnetic data

NASA Astrophysics Data System (ADS)

Pak, Yong-Chol; Li, Tonglin; Kim, Gang-Sop

2017-08-01

We have developed a data-space multiple cross-gradient joint inversion algorithm, and validated it through synthetic tests and applied it to magnetotelluric (MT), gravity and magnetic datasets acquired along a 95 km profile in Benxi-Ji'an area of northeastern China. To begin, we discuss a generalized cross-gradient joint inversion for multiple datasets and model parameters sets, and formulate it in data space. The Lagrange multiplier required for the structural coupling in the data-space method is determined using an iterative solver to avoid calculation of the inverse matrix in solving the large system of equations. Next, using model-space and data-space methods, we inverted the synthetic data and field data. Based on our result, the joint inversion in data-space not only delineates geological bodies more clearly than the separate inversion, but also yields nearly equal results with the one in model-space while consuming much less memory.

Cosmic-Ray Background Flux Model based on a Gamma-Ray Large-Area Space Telescope Balloon Flight Engineering Model

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

Mizuno, T

2004-09-03

Cosmic-ray background fluxes were modeled based on existing measurements and theories and are presented here. The model, originally developed for the Gamma-ray Large Area Space Telescope (GLAST) Balloon Experiment, covers the entire solid angle (4{pi} sr), the sensitive energy range of the instrument ({approx} 10 MeV to 100 GeV) and abundant components (proton, alpha, e{sup -}, e{sup +}, {mu}{sup -}, {mu}{sup +} and gamma). It is expressed in analytic functions in which modulations due to the solar activity and the Earth geomagnetism are parameterized. Although the model is intended to be used primarily for the GLAST Balloon Experiment, model functionsmore » in low-Earth orbit are also presented and can be used for other high energy astrophysical missions. The model has been validated via comparison with the data of the GLAST Balloon Experiment.« less

JWST Point Spread Function Quality and Stability: Ground Testing, Integrated Modeling, and Space Validation

NASA Technical Reports Server (NTRS)

McElwain, Michael; Van Gorkom, Kyle; Bowers, Charles W.; Carnahan, Timothy M.; Kimble, Randy A.; Knight, J. Scott; Lightsey, Paul; Maghami, Peiman G.; Mustelier, David; Niedner, Malcolm B.;

Advanced Video Analysis Needs for Human Performance Evaluation

NASA Technical Reports Server (NTRS)

Campbell, Paul D.

1994-01-01

Evaluators of human task performance in space missions make use of video as a primary source of data. Extraction of relevant human performance information from video is often a labor-intensive process requiring a large amount of time on the part of the evaluator. Based on the experiences of several human performance evaluators, needs were defined for advanced tools which could aid in the analysis of video data from space missions. Such tools should increase the efficiency with which useful information is retrieved from large quantities of raw video. They should also provide the evaluator with new analytical functions which are not present in currently used methods. Video analysis tools based on the needs defined by this study would also have uses in U.S. industry and education. Evaluation of human performance from video data can be a valuable technique in many industrial and institutional settings where humans are involved in operational systems and processes.

Visual interface for space and terrestrial analysis

NASA Technical Reports Server (NTRS)

Dombrowski, Edmund G.; Williams, Jason R.; George, Arthur A.; Heckathorn, Harry M.; Snyder, William A.

1995-01-01

The management of large geophysical and celestial data bases is now, more than ever, the most critical path to timely data analysis. With today's large volume data sets from multiple satellite missions, analysts face the task of defining useful data bases from which data and metadata (information about data) can be extracted readily in a meaningful way. Visualization, following an object-oriented design, is a fundamental method of organizing and handling data. Humans, by nature, easily accept pictorial representations of data. Therefore graphically oriented user interfaces are appealing, as long as they remain simple to produce and use. The Visual Interface for Space and Terrestrial Analysis (VISTA) system, currently under development at the Naval Research Laboratory's Backgrounds Data Center (BDC), has been designed with these goals in mind. Its graphical user interface (GUI) allows the user to perform queries, visualization, and analysis of atmospheric and celestial backgrounds data.

GrouseFlocks: steerable exploration of graph hierarchy space.

PubMed

Archambault, Daniel; Munzner, Tamara; Auber, David

2008-01-01

Several previous systems allow users to interactively explore a large input graph through cuts of a superimposed hierarchy. This hierarchy is often created using clustering algorithms or topological features present in the graph. However, many graphs have domain-specific attributes associated with the nodes and edges, which could be used to create many possible hierarchies providing unique views of the input graph. GrouseFlocks is a system for the exploration of this graph hierarchy space. By allowing users to see several different possible hierarchies on the same graph, the system helps users investigate graph hierarchy space instead of a single fixed hierarchy. GrouseFlocks provides a simple set of operations so that users can create and modify their graph hierarchies based on selections. These selections can be made manually or based on patterns in the attribute data provided with the graph. It provides feedback to the user within seconds, allowing interactive exploration of this space.

\\Space: A new code to estimate \\temp, \\logg, and elemental abundances

NASA Astrophysics Data System (ADS)

Boeche, C.

2016-09-01

\\Space is a FORTRAN95 code that derives stellar parameters and elemental abundances from stellar spectra. To derive these parameters, \\Space does not measure equivalent widths of lines nor it uses templates of synthetic spectra, but it employs a new method based on a library of General Curve-Of-Growths. To date \\Space works on the wavelength range 5212-6860 Å and 8400-8921 Å, and at the spectral resolution R=2000-20000. Extensions of these limits are possible. \\Space is a highly automated code suitable for application to large spectroscopic surveys. A web front end to this service is publicly available at http://dc.g-vo.org/SP_ACE together with the library and the binary code.

Space Station tethered refueling facility operations

NASA Technical Reports Server (NTRS)

Kiefel, E. R.; Rudolph, L. K.; Fester, D. A.

1986-01-01

The space-based orbital transfer vehicle will require a large cryogenic fuel storage facility at the Space Station. An alternative to fuel storage onboard the Space Station, is on a tethered orbital refueling facility (TORF) which is separated from the Space Station by a sufficient distance to induce a gravity gradient to settle the propellants. Facility operations are a major concern associated with a tethered LO2/LH2 storage depot. A study was carried out to analyze these operations so as to identify the preferred TORF deployment direction (up or down) and whether the TORF should be permanently or intermittently deployed. The analyses considered safety, contamination, rendezvous, servicing, transportation rate, communication, and viewing. An upwardly, intermittently deployed facility is the preferred configuration for a tethered cryogenic fuel storage.

Space Science at Los Alamos National Laboratory

NASA Astrophysics Data System (ADS)

Smith, Karl

2017-09-01

The Space Science and Applications group (ISR-1) in the Intelligence and Space Research (ISR) division at the Los Alamos National Laboratory lead a number of space science missions for civilian and defense-related programs. In support of these missions the group develops sensors capable of detecting nuclear emissions and measuring radiations in space including γ-ray, X-ray, charged-particle, and neutron detection. The group is involved in a number of stages of the lifetime of these sensors including mission concept and design, simulation and modeling, calibration, and data analysis. These missions support monitoring of the atmosphere and near-Earth space environment for nuclear detonations as well as monitoring of the local space environment including space-weather type events. Expertise in this area has been established over a long history of involvement with cutting-edge projects continuing back to the first space based monitoring mission Project Vela. The group's interests cut across a large range of topics including non-proliferation, space situational awareness, nuclear physics, material science, space physics, astrophysics, and planetary physics.

Managing Analysis Models in the Design Process

NASA Technical Reports Server (NTRS)

Briggs, Clark

2006-01-01

Design of large, complex space systems depends on significant model-based support for exploration of the design space. Integrated models predict system performance in mission-relevant terms given design descriptions and multiple physics-based numerical models. Both the design activities and the modeling activities warrant explicit process definitions and active process management to protect the project from excessive risk. Software and systems engineering processes have been formalized and similar formal process activities are under development for design engineering and integrated modeling. JPL is establishing a modeling process to define development and application of such system-level models.

Large array of 2048 tilting micromirrors for astronomical spectroscopy: optical and cryogenic characterization

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Canonica, Michael; Lanzoni, Patrick; Noell, Wilfried; Lani, Sebastien

2014-03-01

Multi-object spectroscopy (MOS) is a powerful tool for space and ground-based telescopes for the study of the formation and evolution of galaxies. This technique requires a programmable slit mask for astronomical object selection. We are engaged in a European development of micromirror arrays (MMA) for generating reflective slit masks in future MOS, called MIRA. MMA with 100 × 200 μm2 single-crystal silicon micromirrors were successfully designed, fabricated and tested. Arrays are composed of 2048 micromirrors (32 x 64) with a peak-to-valley deformation less than 10 nm, a tilt angle of 24° for an actuation voltage of 130 V. The micromirrors were actuated successfully before, during and after cryogenic cooling, down to 162K. The micromirror surface deformation was measured at cryo and is below 30 nm peak-to-valley. These performances demonstrate the ability of such MOEMS device to work as objects selector in future generation of MOS instruments both in ground-based and space telescopes. In order to fill large focal planes (mosaicing of several chips), we are currently developing large micromirror arrays integrated with their electronics.

Large charged drop levitation against gravity

NASA Technical Reports Server (NTRS)

Rhim, Won-Kyu; Chung, Sang Kun; Hyson, Michael T.; Trinh, Eugene H.; Elleman, Daniel D.

1987-01-01

A hybrid electrostatic-acoustic levitator that can levitate and manipulate a large liquid drop in one gravity is presented. To the authors' knowledge, this is the first time such large drops (up to 4 mm in diameter in the case of water) have been levitated against 1-gravity. This makes possible, for the first time, many new experiments both in space and in ground-based laboratories, such as 1)supercooling and superheating, 2) containerless crystal growth from various salt solutions or melts, 3) drop dynamics of oscillating or rotating liquid drops, 4) drop evaporation and Rayleigh bursting, and 5) containerless material processing in space. The digital control system, liquid drop launch process, principles of electrode design, and design of a multipurpose room temperature levitation chamber are described. Preliminary results that demonstrate drop oscillation and rotation, and crystal growth from supersaturated salt solutions are presented.

Large space systems technology, 1981. [conferences

NASA Technical Reports Server (NTRS)

Boyer, W. J. (Compiler)

1982-01-01

A total systems approach including structures, analyses, controls, and antennas is presented as a cohesive, programmatic plan for large space systems. Specifically, program status, structures, materials, and analyses, and control of large space systems are addressed.

The Ultimate Destination: Choice of Interplanetary Exploration Path can define Future of Interstellar Spaceflight

NASA Astrophysics Data System (ADS)

Silin, D. V.

Manned interstellar spaceflight is facing multiple challenges of great magnitude; among them are extremely large distances and the lack of known habitable planets other than Earth. Many of these challenges are applicable to manned space exploration within the Solar System to the same or lesser degree. If these issues are resolved on an interplanetary scale, better position to pursue interstellar exploration can be reached. However, very little progress (if any) was achieved in manned space exploration since the end of Space Race. There is no lack of proposed missions, but all of them require considerable technological and financial efforts to implement while yielding no tangible benefits that would justify their costs. To overcome this obstacle highest priority in future space exploration plans should be assigned to the creation of added value in outer space. This goal can be reached if reductions in space transportation, construction and maintenance of space-based structures costs are achieved. In order to achieve these requirements several key technologies have to be mastered, such as near-Earth object mining, space- based manufacturing, agriculture and structure assembly. To keep cost and difficulty under control next exploration steps can be limited to nearby destinations such as geostationary orbit, low lunar orbit, Moon surface and Sun-Earth L1 vicinity. Completion of such a program will create a solid foundation for further exploration and colonization of the Solar System, solve common challenges of interplanetary and interstellar spaceflight and create useful results for the majority of human population. Another important result is that perception of suitable destinations for interstellar missions will change significantly. If it becomes possible to create habitable and self-sufficient artificial environments in the nearby interplanetary space, Earth-like habitable planets will be no longer required to expand beyond our Solar System. Large fraction of the stars in the observable Universe will become valid targets for interstellar missions.

The improvement of GaN-based light-emitting diodes using nanopatterned sapphire substrate with small pattern spacing

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

Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Wang, Junxi

2014-02-15

Self-assembly SiO{sub 2} nanosphere monolayer template is utilized to fabricate nanopatterned sapphire substrates (NPSSs) with 0-nm, 50-nm, and 120-nm spacing, receptively. The GaN growth on top of NPSS with 0-nm spacing has the best crystal quality because of laterally epitaxial overgrowth. However, GaN growth from pattern top is more difficult to get smooth surface than from pattern bottom. The rougher surface may result in a higher work voltage. The stimulation results of finite-difference time-domain (FDTD) display that too large or too small spacing lead to the reduced light extracted efficiency (LEE) of LEDs. Under a driving current 350 mA, themore » external quantum efficiencies (EQE) of GaN-based LEDs grown on NPSSs with 0-nm, 50-nm, and 120-nm spacing increase by 43.3%, 50.6%, and 39.1%, respectively, compared to that on flat sapphire substrate (FSS). The optimized pattern spacing is 50 nm for the NPSS with 600-nm pattern period.« less

Design study of large area 8 cm x 8 cm wrapthrough cells for space station

NASA Technical Reports Server (NTRS)

Garlick, George F. J.; Lillington, David R.

1987-01-01

The design of large area silicon solar cells for the projected NASA space station is discussed. It is based on the NASA specification for the cells which calls for an 8 cm by 8 cm cell of wrapthrough type with gridded back contacts. The beginning of life (BOL) power must be 1.039 watts per cell or larger and maximum end of life (EOL) after 10 years in the prescribed orbit under an equivalent 1MeV electron radiation damage fluence of 5 times 10 to the 13th power e/square cm. On orbit efficiency is to be optimized by a low thermal absorptance goal (thermal alpha) of .63.

A hypervelocity launcher for simulated large fragment space debris impacts at 10 km/s

NASA Technical Reports Server (NTRS)

Tullos, R. J.; Gray, W. M.; Mullin, S. A.; Cour-Palais, B. G.

1989-01-01

The background, design, and testing of two explosive launchers for simulating large fragment space debris impacts are presented. The objective was to develop a launcher capable of launching one gram aluminum fragments at velocities of 10 km/s. The two launchers developed are based on modified versions of an explosive shaped charge, common in many military weapons. One launcher design has yielded a stable fragment launch of approximately one gram of aluminum at 8.93 km/s velocity. The other design yielded velocities in excess of 10 km/s, but failed to produce a cohesive fragment launch. This work is ongoing, and future plans are given.

How Project Managers Really Manage: An Indepth Look at Some Managers of Large, Complex NASA Projects

NASA Technical Reports Server (NTRS)

Mulenburg, Gerald M.; Impaeilla, Cliff (Technical Monitor)

2000-01-01

This paper reports on a research study by the author that examined ten contemporary National Aeronautics and Space Administration (NASA) complex projects. In-depth interviews with the project managers of these projects provided qualitative data about the inner workings of the project and the methodologies used in establishing and managing the projects. The inclusion of a variety of space, aeronautics, and ground based projects from several different NASA research centers helped to reduce potential bias in the findings toward any one type of project, or technical discipline. The findings address the participants and their individual approaches. The discussion includes possible implications for project managers of other large, complex, projects.

Protein crystal growth in microgravity review of large scale temperature induction method: Bovine insulin, human insulin and human α-interferon

NASA Astrophysics Data System (ADS)

Long, Marianna M.; Bishop, John Bradford; Delucas, Lawrence J.; Nagabhushan, Tattanhalli L.; Reichert, Paul; Smith, G. David

1997-01-01

The Protein Crystal Growth Facility (PCF) is space-flight hardware that accommodates large scale protein crystal growth experiments using temperature change as the inductive step. Recent modifications include specialized instrumentation for monitoring crystal nucleation with laser light scattering. This paper reviews results from its first seven flights on the Space Shuttle, the last with laser light scattering instrumentation in place. The PCF's objective is twofold: (1) the production of high quality protein crystals for x-ray analysis and subsequent structure-based drug design and (2) preparation of a large quantity of relatively contaminant free crystals for use as time-release protein pharmaceuticals. The first three Shuttle flights with bovine insulin constituted the PCF's proof of concept, demonstrating that the space-grown crystals were larger and diffracted to higher resolution than their earth-grown counterparts. The later four PCF missions were used to grow recombinant human insulin crystals for x-ray analysis and continue productions trials aimed at the development of a processing facility for crystalline recombinant a-interferon.

A method for modeling contact dynamics for automated capture mechanisms

NASA Technical Reports Server (NTRS)

Williams, Philip J.

1991-01-01

Logicon Control Dynamics develops contact dynamics models for space-based docking and berthing vehicles. The models compute contact forces for the physical contact between mating capture mechanism surfaces. Realistic simulation requires proportionality constants, for calculating contact forces, to approximate surface stiffness of contacting bodies. Proportionality for rigid metallic bodies becomes quite large. Small penetrations of surface boundaries can produce large contact forces.

Extrasolar Planets Observed with JWST and the ELTs

NASA Technical Reports Server (NTRS)

Deming, L. Drake

2010-01-01

The advent of cryogenic space-borne infrared observatories such as the Spitzer Space Telescope has lead to a revolution in the study of planets and planetary systems orbiting sun-like stars. Already Spitzer has characterized the emergent infrared spectra of close-in giant exoplanets using transit and eclipse techniques. The James Webb Space Telescope (JWST) will be able to extend these studies to superEarth exoplanets orbiting in the habitable zones of M-dwarf stars in the near solar neighborhood. The forthcoming ground-based Extremely Large Telescopes (ELTs) will playa key role in these studies, being especially valuable for spectroscopy at higher spectral resolving powers where large photon fluxes are needed. The culmination of this work within the next two decades will be the detection and spectral characterization of the major molecular constituents in the atmosphere of a habitable superEarth orbiting a nearby lower main sequence star.

Spacecraft Dynamics and Control Program at AFRPL

NASA Technical Reports Server (NTRS)

Das, A.; Slimak, L. K. S.; Schloegel, W. T.

1986-01-01

A number of future DOD and NASA spacecraft such as the space based radar will be not only an order of magnitude larger in dimension than the current spacecraft, but will exhibit extreme structural flexibility with very low structural vibration frequencies. Another class of spacecraft (such as the space defense platforms) will combine large physical size with extremely precise pointing requirement. Such problems require a total departure from the traditional methods of modeling and control system design of spacecraft where structural flexibility is treated as a secondary effect. With these problems in mind, the Air Force Rocket Propulsion Laboratory (AFRPL) initiated research to develop dynamics and control technology so as to enable the future large space structures (LSS). AFRPL's effort in this area can be subdivided into the following three overlapping areas: (1) ground experiments, (2) spacecraft modeling and control, and (3) sensors and actuators. Both the in-house and contractual efforts of the AFRPL in LSS are summarized.

Experimental demonstration of active vibration control for flexible structures

NASA Technical Reports Server (NTRS)

Phillips, Douglas J.; Hyland, David C.; Collins, Emmanuel G., Jr.

1990-01-01

Active vibration control of flexible structures for future space missions is addressed. Three experiments that successfully demonstrate control of flexible structures are described. The first is the pendulum experiment. The structure is a 5-m compound pendulum and was designed as an end-to-end test bed for a linear proof mass actuator and its supporting electronics. Experimental results are shown for a maximum-entropy/optimal-projection controller designed to achieve 5 percent damping in the first two pendulum modes. The second experiment was based upon the Harris Multi-Hex prototype experiment (MHPE) apparatus. This is a large optical reflector structure comprising a seven-panel array and supporting truss which typifies a number of generic characteristics of large space systems. The third experiment involved control design and implementation for the ACES structure at NASA Marshall Space Flight Center. The authors conclude with some remarks on the lessons learned from conducting these experiments.

How Prevalent Is Object-Based Attention?

PubMed Central

Pilz, Karin S.; Roggeveen, Alexa B.; Creighton, Sarah E.; Bennett, Patrick J.; Sekuler, Allison B.

2012-01-01

Previous research suggests that visual attention can be allocated to locations in space (space-based attention) and to objects (object-based attention). The cueing effects associated with space-based attention tend to be large and are found consistently across experiments. Object-based attention effects, however, are small and found less consistently across experiments. In three experiments we address the possibility that variability in object-based attention effects across studies reflects low incidence of such effects at the level of individual subjects. Experiment 1 measured space-based and object-based cueing effects for horizontal and vertical rectangles in 60 subjects comparing commonly used target detection and discrimination tasks. In Experiment 2 we ran another 120 subjects in a target discrimination task in which rectangle orientation varied between subjects. Using parametric statistical methods, we found object-based effects only for horizontal rectangles. Bootstrapping methods were used to measure effects in individual subjects. Significant space-based cueing effects were found in nearly all subjects in both experiments, across tasks and rectangle orientations. However, only a small number of subjects exhibited significant object-based cueing effects. Experiment 3 measured only object-based attention effects using another common paradigm and again, using bootstrapping, we found only a small number of subjects that exhibited significant object-based cueing effects. Our results show that object-based effects are more prevalent for horizontal rectangles, which is in accordance with the theory that attention may be allocated more easily along the horizontal meridian. The fact that so few individuals exhibit a significant object-based cueing effect presumably is why previous studies of this effect might have yielded inconsistent results. The results from the current study highlight the importance of considering individual subject data in addition to commonly used statistical methods. PMID:22348018

Overview of NASA's Space Solar Power Technology Advanced Research and Development Program

NASA Technical Reports Server (NTRS)

Howell, Joe; Mankins, John C.; Davis, N. Jan (Technical Monitor)

2001-01-01

Large solar power satellite (SPS) systems that might provide base load power into terrestrial markets were examined extensively in the 1970s by the US Department of Energy (DOE) and the National Aeronautics and Space Administration (NASA). Following a hiatus of about 15 years, the subject of space solar power (SSP) was reexamined by NASA from 1995-1997 in the 'fresh look' study, and during 1998 in an SSP 'concept definition study', and during 1999-2000 in the SSP Exploratory Research and Technology (SERT) program. As a result of these efforts, during 2001, NASA has initiated the SSP Technology Advanced Research and Development (STAR-Dev) program based on informed decisions. The goal of the STAR-Dev program is to conduct preliminary strategic technology research and development to enable large, multi-megawatt to gigawatt-class space solar power (SSP) systems and wireless power transmission (WPT) for government missions and commercial markets (in-space and terrestrial). Specific objectives include: (1) Release a NASA Research Announcement (NRA) for SSP Projects; (2) Conduct systems studies; (3) Develop Component Technologies; (4) Develop Ground and Flight demonstration systems; and (5) Assess and/or Initiate Partnerships. Accomplishing these objectives will allow informed future decisions regarding further SSP and related research and development investments by both NASA management and prospective external partners. In particular, accomplishing these objectives will also guide further definition of SSP and related technology roadmaps including performance objectives, resources and schedules; including 'multi-purpose' applications (commercial, science, and other government).

Autonomy for SOHO Ground Operations

NASA Technical Reports Server (NTRS)

Truszkowski, Walt; Netreba, Nick; Ginn, Don; Mandutianu, Sanda; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

The SOLAR and HELIOSPHERIC OBSERVATORY (SOHO) project [SOHO Web Page] is being carried out by the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) as a cooperative effort between the two agencies in the framework of the Solar Terrestrial Science Program (STSP) comprising SOHO and other missions. SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by Matra, and instruments were provided by European and American scientists. There are nine European Principal Investigators (PI's) and three American ones. Large engineering teams and more than 200 co-investigators from many institutions support the PI's in the development of the instruments and in the preparation of their operations and data analysis. NASA is responsible for the launch and mission operations. Large radio dishes around the world, which form NASA's Deep Space Network (DSN), are used to track the spacecraft beyond the Earths orbit. Mission control is based at Goddard Space Flight Center in Maryland. The agent group at the NASA Goddard Space Flight Center, in collaboration with JPL, is currently involved with the design and development of an agent-based system to provide intelligent interactions with the control center personnel for SOHO. The basic approach that is being taken is to develop a sub-community of agents for each major subsystem of SOHO and to integrate these sub-communities into an overall SOHO community. Agents in all sub-communities will be capable of advanced understanding (deep reasoning) of the associated spacecraft subsystem.

A parallel orbital-updating based plane-wave basis method for electronic structure calculations

NASA Astrophysics Data System (ADS)

Pan, Yan; Dai, Xiaoying; de Gironcoli, Stefano; Gong, Xin-Gao; Rignanese, Gian-Marco; Zhou, Aihui

2017-11-01

Motivated by the recently proposed parallel orbital-updating approach in real space method [1], we propose a parallel orbital-updating based plane-wave basis method for electronic structure calculations, for solving the corresponding eigenvalue problems. In addition, we propose two new modified parallel orbital-updating methods. Compared to the traditional plane-wave methods, our methods allow for two-level parallelization, which is particularly interesting for large scale parallelization. Numerical experiments show that these new methods are more reliable and efficient for large scale calculations on modern supercomputers.

Technologies for low radio frequency observations of the Cosmic Dawn

NASA Astrophysics Data System (ADS)

Jones, D. L.

2014-03-01

The Jet Propulsion Laboratory (JPL) is developing concepts and technologies for low frequency radio astronomy space missions aimed at observing highly redshifted neutral Hydrogen from the Dark Ages. This is the period of cosmic history between the recombination epoch when the microwave background radiation was produced and the re-ionization of the intergalactic medium by the first generation of stars (Cosmic Dawn). This period, at redshifts z > ~20, is a critical epoch for the formation and evolution of large-scale structure in the universe. The 21-cm spectral line of Hydrogen provides the most promising method for directly studying the Dark Ages, but the corresponding frequencies at such large redshifts are only tens of MHz and thus require space-based observations to avoid terrestrial RFI and ionospheric absorption and refraction. This paper reports on the status of several low frequency technology development activities at JPL, including deployable bi-conical dipoles for a planned lunar-orbiting mission, and both rover-deployed and inflation-deployed long dipole antennas for use on the lunar surface. In addition, recent results from laboratory testing of low frequency receiver designs are presented. Finally, several concepts for space-based imaging interferometers utilizing deployable low frequency antennas are described. Some of these concepts involve large numbers of antennas and consequently a large digital cross-correlator will be needed. JPL has studied correlator architectures that greatly reduce the DC power required for this step, which can dominate the power consumption of real-time signal processing. Strengths and weaknesses of each mission concept are discussed in the context of the additional technology development required.

Challenges of Communications and Tracking for Solar System Small Body Exploration

NASA Technical Reports Server (NTRS)

Rush, John J.; Lichten, Stephen M.; Srinivasan, Jeffrey M.

2011-01-01

This presentation will address: (1) Communications capabilities that will be needed for space missions for Small Planetary Body exploration (2) Utilization of large ground-based radar capabilities for Small Body remote sensing and mission planning

Start of space tourism

NASA Astrophysics Data System (ADS)

Nagatomo, Makoto

1993-03-01

Space tourism means commercialization of manned space flight. From the early stage of space development, space commercialization is a profound theme in multidisciplinary fields, on the basis of a principle that the outcomes of advanced technique developed by tax should be returned to citizens. In these days, space satellite system in which users pay a fee for utilization has succeeded commercially in business such as communication network or broadcasting, and an attempt has been made to observe the earth from outer space to resolve global problems, such as environmental destruction. There is also an increasing interest in space tourism, however, many obstacles should be overcome for the realization, especially the medical problems such as effect of acceleration, cosmic ray, noise or weightless condition. In addition, the space flight business should be managed on the commercial base so that reasonable cost and large number of passengers are essential. It is necessary to design rockets suitable for tourism. For attractive design, the policy of space tourism should be clarified.

Comparative Performance in Single-Port Versus Multiport Minimally Invasive Surgery, and Small Versus Large Operative Working Spaces: A Preclinical Randomized Crossover Trial.

PubMed

Marcus, Hani J; Seneci, Carlo A; Hughes-Hallett, Archie; Cundy, Thomas P; Nandi, Dipankar; Yang, Guang-Zhong; Darzi, Ara

2016-04-01

Surgical approaches such as transanal endoscopic microsurgery, which utilize small operative working spaces, and are necessarily single-port, are particularly demanding with standard instruments and have not been widely adopted. The aim of this study was to compare simultaneously surgical performance in single-port versus multiport approaches, and small versus large working spaces. Ten novice, 4 intermediate, and 1 expert surgeons were recruited from a university hospital. A preclinical randomized crossover study design was implemented, comparing performance under the following conditions: (1) multiport approach and large working space, (2) multiport approach and intermediate working space, (3) single-port approach and large working space, (4) single-port approach and intermediate working space, and (5) single-port approach and small working space. In each case, participants performed a peg transfer and pattern cutting tasks, and each task repetition was scored. Intermediate and expert surgeons performed significantly better than novices in all conditions (P < .05). Performance in single-port surgery was significantly worse than multiport surgery (P < .01). In multiport surgery, there was a nonsignificant trend toward worsened performance in the intermediate versus large working space. In single-port surgery, there was a converse trend; performances in the intermediate and small working spaces were significantly better than in the large working space. Single-port approaches were significantly more technically challenging than multiport approaches, possibly reflecting loss of instrument triangulation. Surprisingly, in single-port approaches, in which triangulation was no longer a factor, performance in large working spaces was worse than in intermediate and small working spaces. © The Author(s) 2015.

Observations of the Earth's magnetic field from the Space Station: Measurement at high and extremely low altitude using Space Station-controlled free-flyers

NASA Technical Reports Server (NTRS)

Webster, W., Jr.; Frawley, J. J.; Stefanik, M.

1984-01-01

Simulation studies established that the main (core), crustal and electrojet components of the Earth's magnetic field can be observed with greater resolution or over a longer time-base than is presently possible by using the capabilities provided by the space station. Two systems are studied. The first, a large lifetime, magnetic monitor would observe the main field and its time variation. The second, a remotely-piloted, magnetic probe would observe the crustal field at low altitude and the electrojet field in situ. The system design and the scientific performance of these systems is assessed. The advantages of the space station are reviewed.

Machine intelligence and robotics: Report of the NASA study group. Executive summary

NASA Technical Reports Server (NTRS)

1979-01-01

A brief overview of applications of machine intelligence and robotics in the space program is given. These space exploration robots, global service robots to collect data for public service use on soil conditions, sea states, global crop conditions, weather, geology, disasters, etc., from Earth orbit, space industrialization and processing technologies, and construction of large structures in space. Program options for research, advanced development, and implementation of machine intelligence and robot technology for use in program planning are discussed. A vigorous and long-range program to incorporate and keep pace with state of the art developments in computer technology, both in spaceborne and ground-based computer systems is recommended.

Large numbers hypothesis. IV - The cosmological constant and quantum physics

NASA Technical Reports Server (NTRS)

Adams, P. J.

1983-01-01

In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.

Study and design of cryogenic propellant acquisition systems. Volume 1: Design studies

NASA Technical Reports Server (NTRS)

Burge, G. W.; Blackmon, J. B.

1973-01-01

An in-depth study and selection of practical propellant surface tension acquisition system designs for two specific future cryogenic space vehicles, an advanced cryogenic space shuttle auxiliary propulsion system and an advanced space propulsion module is reported. A supporting laboratory scale experimental program was also conducted to provide design information critical to concept finalization and selection. Designs using localized pressure isolated surface tension screen devices were selected for each application and preliminary designs were generated. Based on these designs, large scale acquisition prototype hardware was designed and fabricated to be compatible with available NASA-MSFC feed system hardware.

Resident Space Object Characterization and Behavior Understanding via Machine Learning and Ontology-based Bayesian Networks

NASA Astrophysics Data System (ADS)

Furfaro, R.; Linares, R.; Gaylor, D.; Jah, M.; Walls, R.

2016-09-01

In this paper, we present an end-to-end approach that employs machine learning techniques and Ontology-based Bayesian Networks (BN) to characterize the behavior of resident space objects. State-of-the-Art machine learning architectures (e.g. Extreme Learning Machines, Convolutional Deep Networks) are trained on physical models to learn the Resident Space Object (RSO) features in the vectorized energy and momentum states and parameters. The mapping from measurements to vectorized energy and momentum states and parameters enables behavior characterization via clustering in the features space and subsequent RSO classification. Additionally, Space Object Behavioral Ontologies (SOBO) are employed to define and capture the domain knowledge-base (KB) and BNs are constructed from the SOBO in a semi-automatic fashion to execute probabilistic reasoning over conclusions drawn from trained classifiers and/or directly from processed data. Such an approach enables integrating machine learning classifiers and probabilistic reasoning to support higher-level decision making for space domain awareness applications. The innovation here is to use these methods (which have enjoyed great success in other domains) in synergy so that it enables a "from data to discovery" paradigm by facilitating the linkage and fusion of large and disparate sources of information via a Big Data Science and Analytics framework.

Systems definition study for shuttle demonstration flights of large space structures. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1979-01-01

The development of large space structure technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. Definition of a flight demonstration involving an Automated Beam Builder and the building and assembling of large structures is presented.

A clustering-based graph Laplacian framework for value function approximation in reinforcement learning.

PubMed

Xu, Xin; Huang, Zhenhua; Graves, Daniel; Pedrycz, Witold

2014-12-01

In order to deal with the sequential decision problems with large or continuous state spaces, feature representation and function approximation have been a major research topic in reinforcement learning (RL). In this paper, a clustering-based graph Laplacian framework is presented for feature representation and value function approximation (VFA) in RL. By making use of clustering-based techniques, that is, K-means clustering or fuzzy C-means clustering, a graph Laplacian is constructed by subsampling in Markov decision processes (MDPs) with continuous state spaces. The basis functions for VFA can be automatically generated from spectral analysis of the graph Laplacian. The clustering-based graph Laplacian is integrated with a class of approximation policy iteration algorithms called representation policy iteration (RPI) for RL in MDPs with continuous state spaces. Simulation and experimental results show that, compared with previous RPI methods, the proposed approach needs fewer sample points to compute an efficient set of basis functions and the learning control performance can be improved for a variety of parameter settings.

Fiber-based laser MOPA transmitter packaging for space environment

NASA Astrophysics Data System (ADS)

Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Numata, Kenji; Wu, Stewart; Gonzales, Brayler; Han, Lawrence; Fahey, Molly; Plants, Michael; Rodriguez, Michael; Allan, Graham; Abshire, James; Nicholson, Jeffrey; Hariharan, Anand; Mamakos, William; Bean, Brian

2018-02-01

NASA's Goddard Space Flight Center has been developing lidar to remotely measure CO2 and CH4 in the Earth's atmosphere. The ultimate goal is to make space-based satellite measurements with global coverage. We are working on maturing the technology readiness of a fiber-based, 1.57-micron wavelength laser transmitter designed for use in atmospheric CO2 remote-sensing. To this end, we are building a ruggedized prototype to demonstrate the required power and performance and survive the required environment. We are building a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture. The laser is a wavelength-locked, single frequency, externally modulated DBR operating at 1.57-micron followed by erbium-doped fiber amplifiers. The last amplifier stage is a polarization-maintaining, very-large-mode-area fiber with 1000 μm2 effective area pumped by a Raman fiber laser. The optical output is single-frequency, one microsecond pulses with >450 μJ pulse energy, 7.5 KHz repetition rate, single spatial mode, and < 20 dB polarization extinction.

Inventing a Space Mission: The Story of the Herschel Space Observatory

NASA Astrophysics Data System (ADS)

Minier, Vincent; Bonnet, Roger-Maurice; Bontems, Vincent; de Graauw, Thijs; Griffin, Matt; Helmich, Frank; Pilbratt, Göran; Volonte, Sergio

This book describes prominent technological achievements within a very successful space science mission: the Herschel space observatory. Focusing on the various processes of innovation it offers an analysis and discussion of the social, technological and scientific context of the mission that paved the way to its development. It addresses the key question raised by these processes in our modern society, i.e.: how knowledge management of innovation set the conditions for inventing the future? In that respect the book is based on a transdisciplinary analysis of the programmatic complexity of Herschel, with inputs from space scientists, managers, philosophers, and engineers. This book is addressed to decision makers, not only in space science, but also in other industries and sciences using or building large machines. It is also addressed to space engineers and scientists as well as students in science and management.

Nonideal ultrathin mantle cloak for electrically large conducting cylinders.

PubMed

Liu, Shuo; Zhang, Hao Chi; Xu, He-Xiu; Cui, Tie Jun

2014-09-01

Based on the concept of the scattering cancellation technique, we propose a nonideal ultrathin mantle cloak that can efficiently suppress the total scattering cross sections of an electrically large conducting cylinder (over one free-space wavelength). The cloaking mechanism is investigated in depth based on the Mie scattering theory and is simultaneously interpreted from the perspective of far-field bistatic scattering and near-field distributions. We remark that, unlike the perfect transformation-optics-based cloak, this nonideal cloaking technique is mainly designed to minimize simultaneously several scattering multipoles of a relatively large geometry around considerably broad bandwidth. Numerical simulations and experimental results show that the antiscattering ability of the metasurface gives rise to excellent total scattering reduction of the electrically large cylinder and remarkable electric-field restoration around the cloak. The outstanding cloaking performance together with the good features of and ultralow profile, flexibility, and easy fabrication predict promising applications in the microwave frequencies.

Design and Flight Testing of an Inflatable Sunshield for the NGST

NASA Technical Reports Server (NTRS)

Adams, Michael L.; Culver, Harry L.; Kaufman, David M.; Pacini, Linda K.; Sturm, James; Lienard, Sebastien

2000-01-01

The Next Generation Space Telescope (NGST) mission is scheduled to launch in 2007 and be stationed at L2 for a mission life of ten years. The large aperture mirror and optical detectors aboard NGST require shielding from the constant solar energy seen at this orbit. The government reference NGST design, called the Yardstick, baselined a sunshield using an inflation deployment system. During the formulation phase, NGST is spending approximately 25% of the overall budget to foster the development of new technology. The goal is to develop and demonstrate enabling or enhancing technology and provide innovative solutions for the design of the NGST observatory. Inflatable technology falls in the category of enhancing technology due to its advantages in weight, stowed volume and cost. The Inflatable Sunshield in Space (ISIS) flight experiment will provide a realistic space flight demonstration of an inflatable sunshield. The supporting technology development program will provide an information base for the design, manufacture, assembly and testing of large thin membranes and inflatable structural elements for space structures. The ISIS experiment will demonstrate the feasibility of using inflatable technology to passively cool optical systems for NGST and provide correlation between analytical predictions and on orbit results. The experiment will be performed on a Hitchhiker/Space Shuttle mission in late 2001. The ISIS mission is an effort to address several major technical challenges of the NGST inflatable sunshield, namely controlled inflation deployment, plenarity and separation of large stretched membranes, space rigidization of inflatable booms, and dynamic modeling and simulation. This paper will describe the design of the flight experiment and the testing to be performed on-orbit.

Lockable Knee Brace Speeds Rehabilitation

NASA Technical Reports Server (NTRS)

2008-01-01

Marshall Space Flight Center develops key transportation and propulsion technologies for the Space Agency. The Center manages propulsion hardware and technologies of the space shuttle, develops the next generation of space transportation and propulsion systems, oversees science and hardware development for the International Space Station, manages projects and studies that will help pave the way back to the Moon, and handles a variety of associated scientific endeavors to benefit space exploration and improve life here on Earth. It is a large and diversified center, and home to a great wealth of design skill. Some of the same mechanical design skill that made its way into the plans for rocket engines and advanced propulsion at this Alabama-based NASA center also worked its way into the design of an orthotic knee joint that is changing the lives of people with weakened quadriceps.

Shape control of large space structures

NASA Technical Reports Server (NTRS)

Hagan, M. T.

1982-01-01

A survey has been conducted to determine the types of control strategies which have been proposed for controlling the vibrations in large space structures. From this survey several representative control strategies were singled out for detailed analyses. The application of these strategies to a simplified model of a large space structure has been simulated. These simulations demonstrate the implementation of the control algorithms and provide a basis for a preliminary comparison of their suitability for large space structure control.

Using the ISS as a testbed to prepare for the next generation of space-based telescopes

NASA Astrophysics Data System (ADS)

Postman, Marc; Sparks, William B.; Liu, Fengchuan; Ess, Kim; Green, Joseph; Carpenter, Kenneth G.; Thronson, Harley; Goullioud, Renaud

2012-09-01

The infrastructure available on the ISS provides a unique opportunity to develop the technologies necessary to assemble large space telescopes. Assembling telescopes in space is a game-changing approach to space astronomy. Using the ISS as a testbed enables a concentration of resources on reducing the technical risks associated with integrating the technologies, such as laser metrology and wavefront sensing and control (WFS&C), with the robotic assembly of major components including very light-weight primary and secondary mirrors and the alignment of the optical elements to a diffraction-limited optical system in space. The capability to assemble the optical system and remove and replace components via the existing ISS robotic systems such as the Special Purpose Dexterous Manipulator (SPDM), or by the ISS Flight Crew, allows for future experimentation as well as repair if necessary. In 2015, first light will be obtained by the Optical Testbed and Integration on ISS eXperiment (OpTIIX), a small 1.5-meter optical telescope assembled on the ISS. The primary objectives of OpTIIX include demonstrating telescope assembly technologies and end-to-end optical system technologies that will advance future large optical telescopes.

Adding EUV reflectance to aluminum-coated mirrors for space-based observation

NASA Astrophysics Data System (ADS)

Allred, David D.; Turley, R. Steven; Thomas, Stephanie M.; Willett, Spencer G.; Greenburg, Michael J.; Perry, Spencer B.

2017-09-01

Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1 . Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials.

Deep Space Wide Area Search Strategies

NASA Astrophysics Data System (ADS)

Capps, M.; McCafferty, J.

There is an urgent need to expand the space situational awareness (SSA) mission beyond catalog maintenance to providing near real-time indications and warnings of emerging events. While building and maintaining a catalog of space objects is essential to SSA, this does not address the threat of uncatalogued and uncorrelated deep space objects. The Air Force therefore has an interest in transformative technologies to scan the geostationary (GEO) belt for uncorrelated space objects. Traditional ground based electro-optical sensors are challenged in simultaneously detecting dim objects while covering large areas of the sky using current CCD technology. Time delayed integration (TDI) scanning has the potential to enable significantly larger coverage rates while maintaining sensitivity for detecting near-GEO objects. This paper investigates strategies of employing TDI sensing technology from a ground based electro-optical telescope, toward providing tactical indications and warnings of deep space threats. We present results of a notional wide area search TDI sensor that scans the GEO belt from three locations: Maui, New Mexico, and Diego Garcia. Deep space objects in the NASA 2030 debris catalog are propagated over multiple nights as an indicative data set to emulate notional uncatalogued near-GEO orbits which may be encountered by the TDI sensor. Multiple scan patterns are designed and simulated, to compare and contrast performance based on 1) efficiency in coverage, 2) number of objects detected, and 3) rate at which detections occur, to enable follow-up observations by other space surveillance network (SSN) sensors. A step-stare approach is also modeled using a dedicated, co-located sensor notionally similar to the Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) tower. Equivalent sensitivities are assumed. This analysis quantifies the relative benefit of TDI scanning for the wide area search mission.

Four generations of sodium guide star lasers for adaptive optics in astronomy and space situational awareness

NASA Astrophysics Data System (ADS)

d'Orgeville, Céline; Fetzer, Gregory J.

2016-07-01

This paper recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analyzing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980s and 1990s. These experimental systems were turned into the first laser guide star facilities to equip mediumto- large diameter adaptive optics telescopes, opening a new era of Laser Guide Star Adaptive Optics (LGS AO)-enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000s that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8 to 10m-class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date. Fiber-based sodium lasers are being or will soon be deployed at three astronomical telescopes and two space surveillance stations. These highly promising systems are still relatively large to install on telescopes and they remain significantly expensive to procure and maintain. We are thus proposing to develop a fourth generation of sodium lasers: based on semiconductor technology, these lasers could provide a definitive solution to the problem of sodium LGS AO laser sources for all astronomy and space situational awareness applications.

Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle.

PubMed

Qin, Zong; Wang, Kai; Chen, Fei; Luo, Xiaobing; Liu, Sheng

2010-08-02

In this research, the condition for uniform lighting generated by array of LEDs with large view angle was studied. The luminous intensity distribution of LED is not monotone decreasing with view angle. A LED with freeform lens was designed as an example for analysis. In a system based on LEDs designed in house with a thickness of 20mm and rectangular arrangement, the condition for uniform lighting was derived and the analytical results demonstrated that the uniformity was not decreasing monotonously with the increasing of LED-to-LED spacing. The illuminance uniformities were calculated with Monte Carlo ray tracing simulations and the uniformity was found to increase with the increasing of certain LED-to-LED spacings anomalously. Another type of large view angle LED and different arrangements were discussed in addition. Both analysis and simulation results showed that the method is available for LED array lighting system design on the basis of large view angle LED..

Fabrication of near-net shape graphite/magnesium composites for large mirrors

NASA Astrophysics Data System (ADS)

Wendt, Robert; Misra, Mohan

1990-10-01

Successful development of space-based surveillance and laser systems will require large precision mirrors which are dimensionally stable under thermal, static, and dynamic (i.e., structural vibrations and retargeting) loading conditions. Among the advanced composites under consideration for large space mirrors, graphite fiber reinforced magnesium (Gr/Mg) is an ideal candidate material that can be tailored to obtain an optimum combination of properties, including a high modulus of elasticity, zero coefficient of thermal expansion, low density, and high thermal conductivity. In addition, an innovative technique, combining conventional filament winding and vacuum casting has been developed to produce near-net shape Gr/Mg composites. This approach can significantly reduce the cost of fabricating large mirrors by decreasing required machining. However, since Gr/Mg cannot be polished to a reflective surface, plating is required. This paper will review research at Martin Marietta Astronautics Group on Gr/Mg mirror blank fabrication and measured mechanical and thermal properties. Also, copper plating and polishing methods, and optical surface characteristics will be presented.

Large deviations and mixing for dissipative PDEs with unbounded random kicks

NASA Astrophysics Data System (ADS)

Jakšić, V.; Nersesyan, V.; Pillet, C.-A.; Shirikyan, A.

2018-02-01

We study the problem of exponential mixing and large deviations for discrete-time Markov processes associated with a class of random dynamical systems. Under some dissipativity and regularisation hypotheses for the underlying deterministic dynamics and a non-degeneracy condition for the driving random force, we discuss the existence and uniqueness of a stationary measure and its exponential stability in the Kantorovich-Wasserstein metric. We next turn to the large deviations principle (LDP) and establish its validity for the occupation measures of the Markov processes in question. The proof is based on Kifer’s criterion for non-compact spaces, a result on large-time asymptotics for generalised Markov semigroup, and a coupling argument. These tools combined together constitute a new approach to LDP for infinite-dimensional processes without strong Feller property in a non-compact space. The results obtained can be applied to the two-dimensional Navier-Stokes system in a bounded domain and to the complex Ginzburg-Landau equation.

A Piezoelectric Unimorph Deformable Mirror Concept by Wafer Transfer for Ultra Large Space Telescopes

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok; Shcheglov, Kirill

2002-01-01

Future concepts of ultra large space telescopes include segmented silicon mirrors and inflatable polymer mirrors. Primary mirrors for these systems cannot meet optical surface figure requirements and are likely to generate over several microns of wavefront errors. In order to correct for these large wavefront errors, high stroke optical quality deformable mirrors are required. JPL has recently developed a new technology for transferring an entire wafer-level mirror membrane from one substrate to another. A thin membrane, 100 mm in diameter, has been successfully transferred without using adhesives or polymers. The measured peak-to-valley surface error of a transferred and patterned membrane (1 mm x 1 mm x 0.016 mm) is only 9 nm. The mirror element actuation principle is based on a piezoelectric unimorph. A voltage applied to the piezoelectric layer induces stress in the longitudinal direction causing the film to deform and pull on the mirror connected to it. The advantage of this approach is that the small longitudinal strains obtainable from a piezoelectric material at modest voltages are thus translated into large vertical displacements. Modeling is performed for a unimorph membrane consisting of clamped rectangular membrane with a PZT layer with variable dimensions. The membrane transfer technology is combined with the piezoelectric bimorph actuator concept to constitute a compact deformable mirror device with a large stroke actuation of a continuous mirror membrane, resulting in a compact A0 systems for use in ultra large space telescopes.

Structure-based design of combinatorial mutagenesis libraries

PubMed Central

Verma, Deeptak; Grigoryan, Gevorg; Bailey-Kellogg, Chris

2015-01-01

The development of protein variants with improved properties (thermostability, binding affinity, catalytic activity, etc.) has greatly benefited from the application of high-throughput screens evaluating large, diverse combinatorial libraries. At the same time, since only a very limited portion of sequence space can be experimentally constructed and tested, an attractive possibility is to use computational protein design to focus libraries on a productive portion of the space. We present a general-purpose method, called “Structure-based Optimization of Combinatorial Mutagenesis” (SOCoM), which can optimize arbitrarily large combinatorial mutagenesis libraries directly based on structural energies of their constituents. SOCoM chooses both positions and substitutions, employing a combinatorial optimization framework based on library-averaged energy potentials in order to avoid explicitly modeling every variant in every possible library. In case study applications to green fluorescent protein, β-lactamase, and lipase A, SOCoM optimizes relatively small, focused libraries whose variants achieve energies comparable to or better than previous library design efforts, as well as larger libraries (previously not designable by structure-based methods) whose variants cover greater diversity while still maintaining substantially better energies than would be achieved by representative random library approaches. By allowing the creation of large-scale combinatorial libraries based on structural calculations, SOCoM promises to increase the scope of applicability of computational protein design and improve the hit rate of discovering beneficial variants. While designs presented here focus on variant stability (predicted by total energy), SOCoM can readily incorporate other structure-based assessments, such as the energy gap between alternative conformational or bound states. PMID:25611189

Structure-based design of combinatorial mutagenesis libraries.

PubMed

Verma, Deeptak; Grigoryan, Gevorg; Bailey-Kellogg, Chris

2015-05-01

The development of protein variants with improved properties (thermostability, binding affinity, catalytic activity, etc.) has greatly benefited from the application of high-throughput screens evaluating large, diverse combinatorial libraries. At the same time, since only a very limited portion of sequence space can be experimentally constructed and tested, an attractive possibility is to use computational protein design to focus libraries on a productive portion of the space. We present a general-purpose method, called "Structure-based Optimization of Combinatorial Mutagenesis" (SOCoM), which can optimize arbitrarily large combinatorial mutagenesis libraries directly based on structural energies of their constituents. SOCoM chooses both positions and substitutions, employing a combinatorial optimization framework based on library-averaged energy potentials in order to avoid explicitly modeling every variant in every possible library. In case study applications to green fluorescent protein, β-lactamase, and lipase A, SOCoM optimizes relatively small, focused libraries whose variants achieve energies comparable to or better than previous library design efforts, as well as larger libraries (previously not designable by structure-based methods) whose variants cover greater diversity while still maintaining substantially better energies than would be achieved by representative random library approaches. By allowing the creation of large-scale combinatorial libraries based on structural calculations, SOCoM promises to increase the scope of applicability of computational protein design and improve the hit rate of discovering beneficial variants. While designs presented here focus on variant stability (predicted by total energy), SOCoM can readily incorporate other structure-based assessments, such as the energy gap between alternative conformational or bound states. © 2015 The Protein Society.

Transiting Exoplanet Survey Satellite (TESS)

NASA Technical Reports Server (NTRS)

Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

2012-01-01

The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

Living on the Moon: Will Humans Develop an Unearthly Culture?

ERIC Educational Resources Information Center

Harris, Philip R.

1985-01-01

When a large lunar base is established, possibly by the year 2010, a new space culture will begin to develop. In adapting to their new environment, lunar settlers will develop new lifestyles, new values, and a new vocabulary. (Author)

Challenges for future space power systems

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W., Jr.

1989-01-01

The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. The key to success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience was made. These needs fall into three broad categories-survival, self sufficiency and industrialization. The cost of delivering payloads to orbital locations from low earth orbit (LEO) to Mars was determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options were made. These goals are largely dependent upon orbital location and energy storage needs.

Scale-space measures for graph topology link protein network architecture to function.

PubMed

Hulsman, Marc; Dimitrakopoulos, Christos; de Ridder, Jeroen

2014-06-15

The network architecture of physical protein interactions is an important determinant for the molecular functions that are carried out within each cell. To study this relation, the network architecture can be characterized by graph topological characteristics such as shortest paths and network hubs. These characteristics have an important shortcoming: they do not take into account that interactions occur across different scales. This is important because some cellular functions may involve a single direct protein interaction (small scale), whereas others require more and/or indirect interactions, such as protein complexes (medium scale) and interactions between large modules of proteins (large scale). In this work, we derive generalized scale-aware versions of known graph topological measures based on diffusion kernels. We apply these to characterize the topology of networks across all scales simultaneously, generating a so-called graph topological scale-space. The comprehensive physical interaction network in yeast is used to show that scale-space based measures consistently give superior performance when distinguishing protein functional categories and three major types of functional interactions-genetic interaction, co-expression and perturbation interactions. Moreover, we demonstrate that graph topological scale spaces capture biologically meaningful features that provide new insights into the link between function and protein network architecture. Matlab(TM) code to calculate the scale-aware topological measures (STMs) is available at http://bioinformatics.tudelft.nl/TSSA © The Author 2014. Published by Oxford University Press.

Spotting East African mammals in open savannah from space.

PubMed

Yang, Zheng; Wang, Tiejun; Skidmore, Andrew K; de Leeuw, Jan; Said, Mohammed Y; Freer, Jim

2014-01-01

Knowledge of population dynamics is essential for managing and conserving wildlife. Traditional methods of counting wild animals such as aerial survey or ground counts not only disturb animals, but also can be labour intensive and costly. New, commercially available very high-resolution satellite images offer great potential for accurate estimates of animal abundance over large open areas. However, little research has been conducted in the area of satellite-aided wildlife census, although computer processing speeds and image analysis algorithms have vastly improved. This paper explores the possibility of detecting large animals in the open savannah of Maasai Mara National Reserve, Kenya from very high-resolution GeoEye-1 satellite images. A hybrid image classification method was employed for this specific purpose by incorporating the advantages of both pixel-based and object-based image classification approaches. This was performed in two steps: firstly, a pixel-based image classification method, i.e., artificial neural network was applied to classify potential targets with similar spectral reflectance at pixel level; and then an object-based image classification method was used to further differentiate animal targets from the surrounding landscapes through the applications of expert knowledge. As a result, the large animals in two pilot study areas were successfully detected with an average count error of 8.2%, omission error of 6.6% and commission error of 13.7%. The results of the study show for the first time that it is feasible to perform automated detection and counting of large wild animals in open savannahs from space, and therefore provide a complementary and alternative approach to the conventional wildlife survey techniques.

Okinawa, Japan

NASA Image and Video Library

1991-08-11

The southern half of the island of Okinawa, Japan (26.5N, 128.0E) can be seen in this nearly cloud free view. Okinawa is part of the Ryuku Islands which extend from Taiwan northeastward to Kyushu, southernmost of the Japanese Home Islands. The large military base at Kadena, with large runways, is visible near the center of the scene. Kadena is one of several emergency landing sites around the world for the space shuttle.

Illumination in diverse codimensions

NASA Technical Reports Server (NTRS)

Banks, David C.

1994-01-01

This paper derives a model of diffuse and specular illumination in arbitrarily large dimensions, based on a few characteristics of material and light in three-space. It then describes how to adjust for the anomaly of excess brightness in large codimensions. If a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates both the one dimensional geometry (the grooves or fur) and the two dimensional geometry (the surface).

Space Launch System Complex Decision-Making Process

NASA Technical Reports Server (NTRS)

Lyles, Garry; Flores, Tim; Hundley, Jason; Monk, Timothy; Feldman,Stuart

2012-01-01

The Space Shuttle program has ended and elements of the Constellation Program have either been cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. From Fall 2010 until Spring 2011, an SLS decision-making framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper focuses on the various steps and methods of this process (rather than specific data) that allowed for competing concepts to be compared across a variety of launch vehicle metrics in support of the successful completion of the SLS Mission Concept Review (MCR) milestone.

Modeling subjective evaluation of soundscape quality in urban open spaces: An artificial neural network approach.

PubMed

Yu, Lei; Kang, Jian

2009-09-01

This research aims to explore the feasibility of using computer-based models to predict the soundscape quality evaluation of potential users in urban open spaces at the design stage. With the data from large scale field surveys in 19 urban open spaces across Europe and China, the importance of various physical, behavioral, social, demographical, and psychological factors for the soundscape evaluation has been statistically analyzed. Artificial neural network (ANN) models have then been explored at three levels. It has been shown that for both subjective sound level and acoustic comfort evaluation, a general model for all the case study sites is less feasible due to the complex physical and social environments in urban open spaces; models based on individual case study sites perform well but the application range is limited; and specific models for certain types of location/function would be reliable and practical. The performance of acoustic comfort models is considerably better than that of sound level models. Based on the ANN models, soundscape quality maps can be produced and this has been demonstrated with an example.

Enabling the 2nd Generation in Space: Building Blocks for Large Scale Space Endeavours

NASA Astrophysics Data System (ADS)

Barnhardt, D.; Garretson, P.; Will, P.

Today the world operates within a "first generation" space industrial enterprise, i.e. all industry is on Earth, all value from space is from bits (data essentially), and the focus is Earth-centric, with very limited parts of our population and industry participating in space. We are limited in access, manoeuvring, on-orbit servicing, in-space power, in-space manufacturing and assembly. The transition to a "Starship culture" requires the Earth to progress to a "second generation" space industrial base, which implies the need to expand the economic sphere of activity of mankind outside of an Earth-centric zone and into CIS-lunar space and beyond, with an equal ability to tap the indigenous resources in space (energy, location, materials) that will contribute to an expanding space economy. Right now, there is no comfortable place for space applications that are not discovery science, exploration, military, or established earth bound services. For the most part, space applications leave out -- or at least leave nebulous, unconsolidated, and without a critical mass -- programs and development efforts for infrastructure, industrialization, space resources (survey and process maturation), non-traditional and persistent security situational awareness, and global utilities -- all of which, to a far greater extent than a discovery and exploration program, may help determine the elements of a 2nd generation space capability. We propose a focus to seed the pre-competitive research that will enable global industry to develop the necessary competencies that we currently lack to build large scale space structures on-orbit, that in turn would lay the foundation for long duration spacecraft travel (i.e. key technologies in access, manoeuvrability, etc.). This paper will posit a vision-to-reality for a step wise approach to the types of activities the US and global space providers could embark upon to lay the foundation for the 2nd generation of Earth in space.

Structural Dynamics and Control of Large Space Structures, 1982

NASA Technical Reports Server (NTRS)

Brumfield, M. L. (Compiler)

1983-01-01

Basic research in the control of large space structures is discussed. Active damping and control of flexible beams, active stabilization of flexible antenna feed towers, spacecraft docking, and robust pointing control of large space platform payloads are among the topics discussed.

Active optics as enabling technology for future large missions: current developments for astronomy and Earth observation at ESA

NASA Astrophysics Data System (ADS)

Hallibert, Pascal

2017-09-01

In recent years, a trend for higher resolution has increased the entrance apertures of future optical payloads for both Astronomy and Earth Observation most demanding applications, resulting in new opto-mechanical challenges for future systems based on either monolithic or segmented large primary mirrors. Whether easing feasibility and schedule impact of tight manufacturing and integration constraints or correcting mission-critical in-orbit and commissioning effects, Active Optics constitutes an enabling technology for future large optical space instruments at ESA and needs to reach the necessary maturity in time for future mission selection and implementation. We present here a complete updated overview of our current R and D activities in this field, ranging from deformable space-compatible components to full correction chains including wavefront sensing as well as control and correction algorithms. We share as well our perspectives on the way-forward to technological maturity and implementation within future missions.

Precision segmented reflectors for space applications

NASA Technical Reports Server (NTRS)

Lehman, David H.; Pawlik, Eugene V.; Meinel, Aden B.; Fichter, W. B.

1990-01-01

A project to develop precision segmented reflectors (PSRs) which operate at submillimeter wavelengths is described. The development of a light efficient means for the construction of large-aperture segmented reflecting space-based telescopes is the primary aim of the project. The 20-m Large Deployable Reflector (LDR) telescope is being developed for a survey mission, and it will make use of the reflector panels and materials, structures, and figure control being elaborated for the PSR. The surface accuracy of a 0.9-m PSR panel is shown to be 1.74-micron RMS, the goal of 100-micron RMS positioning accuracy has been achieved for a 4-m erectable structure. A voice-coil actuator for the figure control system architecture demonstrated 1-micron panel control accuracy in a 3-axis evaluation. The PSR technology is demonstrated to be of value for several NASA projects involving optical communications and interferometers as well as missions which make use of large-diameter segmented reflectors.

Precision segmented reflectors for space applications

NASA Astrophysics Data System (ADS)

Lehman, David H.; Pawlik, Eugene V.; Meinel, Aden B.; Fichter, W. B.

1990-08-01

A project to develop precision segmented reflectors (PSRs) which operate at submillimeter wavelengths is described. The development of a light efficient means for the construction of large-aperture segmented reflecting space-based telescopes is the primary aim of the project. The 20-m Large Deployable Reflector (LDR) telescope is being developed for a survey mission, and it will make use of the reflector panels and materials, structures, and figure control being elaborated for the PSR. The surface accuracy of a 0.9-m PSR panel is shown to be 1.74-micron RMS, the goal of 100-micron RMS positioning accuracy has been achieved for a 4-m erectable structure. A voice-coil actuator for the figure control system architecture demonstrated 1-micron panel control accuracy in a 3-axis evaluation. The PSR technology is demonstrated to be of value for several NASA projects involving optical communications and interferometers as well as missions which make use of large-diameter segmented reflectors.

Development of an automated electrical power subsystem testbed for large spacecraft

NASA Technical Reports Server (NTRS)

Hall, David K.; Lollar, Louis F.

1990-01-01

The NASA Marshall Space Flight Center (MSFC) has developed two autonomous electrical power system breadboards. The first breadboard, the autonomously managed power system (AMPS), is a two power channel system featuring energy generation and storage and 24-kW of switchable loads, all under computer control. The second breadboard, the space station module/power management and distribution (SSM/PMAD) testbed, is a two-bus 120-Vdc model of the Space Station power subsystem featuring smart switchgear and multiple knowledge-based control systems. NASA/MSFC is combining these two breadboards to form a complete autonomous source-to-load power system called the large autonomous spacecraft electrical power system (LASEPS). LASEPS is a high-power, intelligent, physical electrical power system testbed which can be used to derive and test new power system control techniques, new power switching components, and new energy storage elements in a more accurate and realistic fashion. LASEPS has the potential to be interfaced with other spacecraft subsystem breadboards in order to simulate an entire space vehicle. The two individual systems, the combined systems (hardware and software), and the current and future uses of LASEPS are described.

Towards a large-scale scalable adaptive heart model using shallow tree meshes

NASA Astrophysics Data System (ADS)

Krause, Dorian; Dickopf, Thomas; Potse, Mark; Krause, Rolf

2015-10-01

Electrophysiological heart models are sophisticated computational tools that place high demands on the computing hardware due to the high spatial resolution required to capture the steep depolarization front. To address this challenge, we present a novel adaptive scheme for resolving the deporalization front accurately using adaptivity in space. Our adaptive scheme is based on locally structured meshes. These tensor meshes in space are organized in a parallel forest of trees, which allows us to resolve complicated geometries and to realize high variations in the local mesh sizes with a minimal memory footprint in the adaptive scheme. We discuss both a non-conforming mortar element approximation and a conforming finite element space and present an efficient technique for the assembly of the respective stiffness matrices using matrix representations of the inclusion operators into the product space on the so-called shallow tree meshes. We analyzed the parallel performance and scalability for a two-dimensional ventricle slice as well as for a full large-scale heart model. Our results demonstrate that the method has good performance and high accuracy.

System Learning via Exploratory Data Analysis: Seeing Both the Forest and the Trees

NASA Astrophysics Data System (ADS)

Habash Krause, L.

2014-12-01

As the amount of observational Earth and Space Science data grows, so does the need for learning and employing data analysis techniques that can extract meaningful information from those data. Space-based and ground-based data sources from all over the world are used to inform Earth and Space environment models. However, with such a large amount of data comes a need to organize those data in a way such that trends within the data are easily discernible. This can be tricky due to the interaction between physical processes that lead to partial correlation of variables or multiple interacting sources of causality. With the suite of Exploratory Data Analysis (EDA) data mining codes available at MSFC, we have the capability to analyze large, complex data sets and quantitatively identify fundamentally independent effects from consequential or derived effects. We have used these techniques to examine the accuracy of ionospheric climate models with respect to trends in ionospheric parameters and space weather effects. In particular, these codes have been used to 1) Provide summary "at-a-glance" surveys of large data sets through categorization and/or evolution over time to identify trends, distribution shapes, and outliers, 2) Discern the underlying "latent" variables which share common sources of causality, and 3) Establish a new set of basis vectors by computing Empirical Orthogonal Functions (EOFs) which represent the maximum amount of variance for each principal component. Some of these techniques are easily implemented in the classroom using standard MATLAB functions, some of the more advanced applications require the statistical toolbox, and applications to unique situations require more sophisiticated levels of programming. This paper will present an overview of the range of tools available and how they might be used for a variety of time series Earth and Space Science data sets. Examples of feature recognition from both 1D and 2D (e.g. imagery) time series data sets will be presented.

Trigger and Reconstruction Algorithms for the Japanese Experiment Module- Extreme Universe Space Observatory (JEM-EUSO)

NASA Technical Reports Server (NTRS)

Adams, J. H., Jr.; Andreev, Valeri; Christl, M. J.; Cline, David B.; Crawford, Hank; Judd, E. G.; Pennypacker, Carl; Watts, J. W.

2007-01-01

The JEM-EUSO collaboration intends to study high energy cosmic ray showers using a large downward looking telescope mounted on the Japanese Experiment Module of the International Space Station. The telescope focal plane is instrumented with approx.300k pixels operating as a digital camera, taking snapshots at approx. 1MHz rate. We report an investigation of the trigger and reconstruction efficiency of various algorithms based on time and spatial analysis of the pixel images. Our goal is to develop trigger and reconstruction algorithms that will allow the instrument to detect energies low enough to connect smoothly to ground-based observations.

A space-based public service platform for terrestrial rescue operations

NASA Technical Reports Server (NTRS)

Fleisig, R.; Bernstein, J.; Cramblit, D. C.

1977-01-01

The space-based Public Service Platform (PSP) is a multibeam, high-gain communications relay satellite that can provide a variety of functions for a large number of people on earth equipped with extremely small, very low cost transceivers. This paper describes the PSP concept, the rationale used to derive the concept, the criteria for selecting specific communication functions to be performed, and the advantages of performing such functions via satellite. The discussion focuses on the benefits of using a PSP for natural disaster warning; control of attendant rescue/assistance operations; and rescue of people in downed aircraft, aboard sinking ships, lost or injured on land.

Pointing and figure control system for a space-based far-IR segmented telescope

NASA Technical Reports Server (NTRS)

Lau, Kenneth

1993-01-01

A pointing and figure control system for two space-based far-IR telescopes, the 10-20 m Large Deployable Reflector and the 3.6 m Submillimeter Intermediate Mission, is described. The figure maintenance control system is designed to counter the optical elements translational and rotational changes induced by long-term thermal drifts that the support structure may experience. The pointing system applies optical truss to telescope pointing; a laser metrology system is used to transfer pointing informaton from an external fine guidance sensor to the telescope optical boresight, defined by the primary mirror, secondary mirror, and focal plane assembly.

X-38 flies free from NASA's B-52 mothership, July 10, 2001

NASA Technical Reports Server (NTRS)

2001-01-01

The second free-flight test of an evolving series of X-38 prototypes took place July 10, 2001 when the X-38 was released from NASA's B-52 mothership over the Edwards Air Force Base range in California's Mojave Desert. Shortly after the photo was taken, a sequenced deployment of a drogue parachute followed by a large parafoil fabric wing slowed the X-38 to enable it to land safely on Rogers Dry Lake at Edwards. NASA engineers from the Dryden Flight Research Center at Edwards, and the Johnson Space Center, Houston, Texas, are developing a 'lifeboat' for the International Space Station based on X-38 research.

X-38 flies free from NASA's B-52 mothership, July 10, 2001

NASA Image and Video Library

2001-07-10

The second free-flight test of an evolving series of X-38 prototypes took place July 10, 2001 when the X-38 was released from NASA's B-52 mothership over the Edwards Air Force Base range in California's Mojave Desert. Shortly after the photo was taken, a sequenced deployment of a drogue parachute followed by a large parafoil fabric wing slowed the X-38 to enable it to land safely on Rogers Dry Lake at Edwards. NASA engineers from the Dryden Flight Research Center at Edwards, and the Johnson Space Center, Houston, Texas, are developing a "lifeboat" for the International Space Station based on X-38 research.

A minimalist approach to receiver architecture

NASA Technical Reports Server (NTRS)

Collins, O.

1991-01-01

New signal processing techniques are described for Deep Space Network radios and a proposed receiver architecture is presented, as well as experimental results on this new receiver's analog front end. The receiver's design employs direct downconversion rather than high speed digitization, and it is just as suitable for use as a space based probe relay receiver as it is for installation at a ground antenna. The advantages of having an inexpensive, shoe box size receiver, which could be carried around to antennas of opportunity, used for spacecraft testing or installed in the base of every antenna in a large array are the force behind this project.

Large Scale Processes and Extreme Floods in Brazil

NASA Astrophysics Data System (ADS)

Ribeiro Lima, C. H.; AghaKouchak, A.; Lall, U.

2016-12-01

Persistent large scale anomalies in the atmospheric circulation and ocean state have been associated with heavy rainfall and extreme floods in water basins of different sizes across the world. Such studies have emerged in the last years as a new tool to improve the traditional, stationary based approach in flood frequency analysis and flood prediction. Here we seek to advance previous studies by evaluating the dominance of large scale processes (e.g. atmospheric rivers/moisture transport) over local processes (e.g. local convection) in producing floods. We consider flood-prone regions in Brazil as case studies and the role of large scale climate processes in generating extreme floods in such regions is explored by means of observed streamflow, reanalysis data and machine learning methods. The dynamics of the large scale atmospheric circulation in the days prior to the flood events are evaluated based on the vertically integrated moisture flux and its divergence field, which are interpreted in a low-dimensional space as obtained by machine learning techniques, particularly supervised kernel principal component analysis. In such reduced dimensional space, clusters are obtained in order to better understand the role of regional moisture recycling or teleconnected moisture in producing floods of a given magnitude. The convective available potential energy (CAPE) is also used as a measure of local convection activities. We investigate for individual sites the exceedance probability in which large scale atmospheric fluxes dominate the flood process. Finally, we analyze regional patterns of floods and how the scaling law of floods with drainage area responds to changes in the climate forcing mechanisms (e.g. local vs large scale).

Commercial Research and Development: Power to Explore, Opportunities from Discovery

NASA Technical Reports Server (NTRS)

Casas, Joseph C.; Nall, Mark; Powers, C. Blake; Henderson, Robin N. (Technical Monitor)

2002-01-01

The technical and economic goals of commercial use of space are laudable, and are addressed as a high priority by almost every national space program and most major aerospace companies the world over. Yet, the focus of most organizational agendas and discussions tends to focus on one or two very narrow enabling aspects of this potentially large technological and economic opportunity. While government sponsored commercial launch activities and private space platforms are an integral part of efforts to leverage the commercial use of space, these activities are possibly one of the smallest parts of creating, a viable and sustainable market for the commercial use of space. Most of the current programs usually do not appropriately address some of the critical issues of the current, already interested, potential space user communities. Current programs place the focus of the majority of the user requirements on the vehicle payload weight and mass performance considerations as the primary payload economical factor in providing a commercial market with a stimulating price for gaining access to the space environment. The larger user challenges of transformation from Earth-based research and development approaches to space environment approaches are not addressed early enough in programs to impact the new business considerations of potential users. Currently, space-based research and development user activities require a large user investment in time, in development of new areas of support expertise, in development of new systems, in risk of schedule to completion, and in long term capital positioning. The larger opportunities for stimulating a strong market driven interest in commercial use of space that could result from the development of vehicle payload "leap ahead technologies" for users are being missed, and there is a real risk of limiting the potentially broader market base to support a more technologically advanced and economically lucrative outcome. A major driving force for strengthening the commercial space activities is not only the technological advances in launch vehicle, or newer satellites, but the myriad of enabling payloads technologies that could, as a goal, result in an almost transparent facilitation to regular CD a, -n access to space and microgravity environments by the future users from the existing Earth-based research and development organizations market segments. Rather than focusing only on developing high lift performance launch vehicles and then developing payloads to fit them, the real focus from a business model perspective should to be on the customer payloads requirements, and on designing launch vehicles and platforms systems for a space transportation and facility infrastructure to support all aspects of the business model for the user market. To harness the full potential of space commercialization, new efforts need to be made to comprehensively examine all the critical business model areas for commercial research, development, and manufacturing in space so as to identify specific products and efforts; to determine how such operations must be both similar to and different from current Earth-based activities; to evaluate the enabling technological devices, processes and efforts so that like efforts can be addressed in a synergistic fashion for maximum user cost effectiveness; to delineate the services that are both needed and can be provided by such activities; and to use this information to drive design and development of space commercialization efforts and policy.

Automated observation scheduling for the VLT

NASA Technical Reports Server (NTRS)

Johnston, Mark D.

1988-01-01

It is becoming increasingly evident that, in order to optimize the observing efficiency of large telescopes, some changes will be required in the way observations are planned and executed. Not all observing programs require the presence of the astronomer at the telescope: for those programs which permit service observing it is possible to better match planned observations to conditions at the telescope. This concept of flexible scheduling has been proposed for the VLT: based on current and predicted environmental and instrumental observations which make the most efficient possible use of valuable time. A similar kind of observation scheduling is already necessary for some space observatories, such as Hubble Space Telescope (HST). Space Telescope Science Institute is presently developing scheduling tools for HST, based on the use of artificial intelligence software development techniques. These tools could be readily adapted for ground-based telescope scheduling since they address many of the same issues. The concept are described on which the HST tools are based, their implementation, and what would be required to adapt them for use with the VLT and other ground-based observatories.

Large space structures controls research and development at Marshall Space Flight Center: Status and future plans

NASA Technical Reports Server (NTRS)

Buchanan, H. J.

1983-01-01

Work performed in Large Space Structures Controls research and development program at Marshall Space Flight Center is described. Studies to develop a multilevel control approach which supports a modular or building block approach to the buildup of space platforms are discussed. A concept has been developed and tested in three-axis computer simulation utilizing a five-body model of a basic space platform module. Analytical efforts have continued to focus on extension of the basic theory and subsequent application. Consideration is also given to specifications to evaluate several algorithms for controlling the shape of Large Space Structures.

A unifying framework for systems modeling, control systems design, and system operation

NASA Technical Reports Server (NTRS)

Dvorak, Daniel L.; Indictor, Mark B.; Ingham, Michel D.; Rasmussen, Robert D.; Stringfellow, Margaret V.

2005-01-01

Current engineering practice in the analysis and design of large-scale multi-disciplinary control systems is typified by some form of decomposition- whether functional or physical or discipline-based-that enables multiple teams to work in parallel and in relative isolation. Too often, the resulting system after integration is an awkward marriage of different control and data mechanisms with poor end-to-end accountability. System of systems engineering, which faces this problem on a large scale, cries out for a unifying framework to guide analysis, design, and operation. This paper describes such a framework based on a state-, model-, and goal-based architecture for semi-autonomous control systems that guides analysis and modeling, shapes control system software design, and directly specifies operational intent. This paper illustrates the key concepts in the context of a large-scale, concurrent, globally distributed system of systems: NASA's proposed Array-based Deep Space Network.

Estimating cetacean carrying capacity based on spacing behaviour.

PubMed

Braithwaite, Janelle E; Meeuwig, Jessica J; Jenner, K Curt S

2012-01-01

Conservation of large ocean wildlife requires an understanding of how they use space. In Western Australia, the humpback whale (Megaptera novaeangliae) population is growing at a minimum rate of 10% per year. An important consideration for conservation based management in space-limited environments, such as coastal resting areas, is the potential expansion in area use by humpback whales if the carrying capacity of existing areas is exceeded. Here we determined the theoretical carrying capacity of a known humpback resting area based on the spacing behaviour of pods, where a resting area is defined as a sheltered embayment along the coast. Two separate approaches were taken to estimate this distance. The first used the median nearest neighbour distance between pods in relatively dense areas, giving a spacing distance of 2.16 km (± 0.94). The second estimated the spacing distance as the radius at which 50% of the population included no other pods, and was calculated as 1.93 km (range: 1.62-2.50 km). Using these values, the maximum number of pods able to fit into the resting area was 698 and 872 pods, respectively. Given an average observed pod size of 1.7 whales, this equates to a carrying capacity estimate of between 1187 and 1482 whales at any given point in time. This study demonstrates that whale pods do maintain a distance from each other, which may determine the number of animals that can occupy aggregation areas where space is limited. This requirement for space has implications when considering boundaries for protected areas or competition for space with the fishing and resources sectors.

Impact of space-based instruments on magnetic star research: past and future

NASA Astrophysics Data System (ADS)

Weiss, WW.; Neiner, C.; Wade, G. A.

2018-01-01

Magnetic stars are observed at a large variety of spectral ranges, frequently with photometric and spectroscopic techniques and on time scales ranging from a 'snap shot' to years, sometimes using data sets which are continuous over many months. The outcome of such observations has been discussed during this conference and many examples have been presented, demonstrating the high scientific significance and gains in our knowledge that result from these observations. A key question that should be addressed is, what are the advantages and requirements of space based research of magnetic stars, particularly in relation to ground based observations? And what are the drawbacks? What are the hopes for the future? In the following, we intend to present an overview that addresses these questions.

Wavefront sensing, control, and pointing

NASA Technical Reports Server (NTRS)

Pitts, Thomas; Sevaston, George; Agronin, Michael; Bely, Pierre; Colavita, Mark; Clampin, Mark; Harvey, James; Idell, Paul; Sandler, Dave; Ulmer, Melville

1992-01-01

A majority of future NASA astrophysics missions from orbiting interferometers to 16-m telescopes on the Moon have, as a common requirement, the need to bring light from a large entrance aperture to the focal plane in a way that preserves the spatial coherence properties of the starlight. Only by preserving the phase of the incoming wavefront, can many scientific observations be made, observations that range from measuring the red shift of quasi-stellar objects (QSO's) to detecting the IR emission of a planet in orbit around another star. New technologies for wavefront sensing, control, and pointing hold the key to advancing our observatories of the future from those already launched or currently under development. As the size of the optical system increases, either to increase the sensitivity or angular resolution of the instrument, traditional technologies for maintaining optical wavefront accuracy become prohibitively expensive or completely impractical. For space-based instruments, the low mass requirement and the large temperature excursions further challenge existing technologies. The Hubble Space Telescope (HST) is probably the last large space telescope to rely on passive means to keep its primary optics stable and the optical system aligned. One needs only look to the significant developments in wavefront sensing, control, and pointing that have occurred over the past several years to appreciate the potential of this technology for transforming the capability of future space observatories. Future developments in space-borne telescopes will be based in part on developments in ground-based systems. Telescopes with rigid primary mirrors much larger than 5 m in diameter are impractical because of gravity loading. New technologies are now being introduced, such as active optics, that address the scale problem and that allow very large telescopes to be built. One approach is a segmented design such as that being pioneered by the W.M. Keck telescope now under construction at the Mauna Kea Observatory. It consists of 36 hexagonal mirror segments, supported on a framework structure, which are positioned by actuators located between the structure and the mirrors. The figure of the telescope is initialized by making observations of a bright star using a Shack Hartmann sensor integrated with a white light interferometer. Then, using sensed data from the mirror edges to control these actuators, the figure of the mosaic of 36 segments is maintained as if it were a rigid primary mirror. Another active optics approach is the use of a thin meniscus mirror with actuators. This technique was demonstrated on the European Southern Observatory's New Technology Telescope (NTT) and is planned for use in the Very Large Telescope (consists of four 8-m apertures), which is now entering the design phase.

A Large Underestimate of Formic Acid from Tropical Fires: Constraints from Space-Borne Measurements.

PubMed

Chaliyakunnel, S; Millet, D B; Wells, K C; Cady-Pereira, K E; Shephard, M W

2016-06-07

Formic acid (HCOOH) is one of the most abundant carboxylic acids and a dominant source of atmospheric acidity. Recent work indicates a major gap in the HCOOH budget, with atmospheric concentrations much larger than expected from known sources. Here, we employ recent space-based observations from the Tropospheric Emission Spectrometer with the GEOS-Chem atmospheric model to better quantify the HCOOH source from biomass burning, and assess whether fire emissions can help close the large budget gap for this species. The space-based data reveal a severe model HCOOH underestimate most prominent over tropical burning regions, suggesting a major missing source of organic acids from fires. We develop an approach for inferring the fractional fire contribution to ambient HCOOH and find, based on measurements over Africa, that pyrogenic HCOOH:CO enhancement ratios are much higher than expected from direct emissions alone, revealing substantial secondary organic acid production in fire plumes. Current models strongly underestimate (by 10 ± 5 times) the total primary and secondary HCOOH source from African fires. If a 10-fold bias were to extend to fires in other regions, biomass burning could produce 14 Tg/a of HCOOH in the tropics or 16 Tg/a worldwide. However, even such an increase would only represent 15-20% of the total required HCOOH source, implying the existence of other larger missing sources.

Technology Challenges and Opportunities for Very Large In-Space Structural Systems

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Dorsey, John T.; Watson, Judith J.

2009-01-01

Space solar power satellites and other large space systems will require creative and innovative concepts in order to achieve economically viable designs. The mass and volume constraints of current and planned launch vehicles necessitate highly efficient structural systems be developed. In addition, modularity and in-space deployment/construction will be enabling design attributes. While current space systems allocate nearly 20 percent of the mass to the primary structure, the very large space systems of the future must overcome subsystem mass allocations by achieving a level of functional integration not yet realized. A proposed building block approach with two phases is presented to achieve near-term solar power satellite risk reduction with accompanying long-term technology advances. This paper reviews the current challenges of launching and building very large space systems from a structures and materials perspective utilizing recent experience. Promising technology advances anticipated in the coming decades in modularity, material systems, structural concepts, and in-space operations are presented. It is shown that, together, the current challenges and future advances in very large in-space structural systems may provide the technology pull/push necessary to make solar power satellite systems more technically and economically feasible.

Active structural control for damping augmentation and compensation of thermal distortion

NASA Technical Reports Server (NTRS)

Sirlin, S. W.

1992-01-01

A large space-based Focus Mission Interferometer is used as a testbed for the NASA Controls and Structures Interaction Program. Impedance-based adaptive structural control and control of thermal disturbances are demonstrated using an end-to-end simulation of the system's optical performance. Attention is also given to integrated optical/structural modeling and a hierarchical, layered control strategy.

Space-based solar power conversion and delivery systems study. Volume 2: Engineering analysis of orbital systems

NASA Technical Reports Server (NTRS)

1976-01-01

Program plans, schedules, and costs are determined for a synchronous orbit-based power generation and relay system. Requirements for the satellite solar power station (SSPS) and the power relay satellite (PRS) are explored. Engineering analysis of large solar arrays, flight mechanics and control, transportation, assembly and maintenance, and microwave transmission are included.

Data discretization for novel resource discovery in large medical data sets.

PubMed Central

Benoît, G.; Andrews, J. E.

2000-01-01

This paper is motivated by the problems of dealing with large data sets in information retrieval. The authors suggest an information retrieval framework based on mathematical principles to organize and permit end-user manipulation of a retrieval set. By adjusting through the interface the weights and types of relationships between query and set members, it is possible to expose unanticipated, novel relationships between the query/document pair. The retrieval set as a whole is parsed into discrete concept-oriented subsets (based on within-set similarity measures) and displayed on screen as interactive "graphic nodes" in an information space, distributed at first based on the vector model (similarity measure of set to query). The result is a visualized map wherein it is possible to identify main concept regions and multiple sub-regions as dimensions of the same data. Users may examine the membership within sub-regions. Based on this framework, a data visualization user interface was designed to encourage users to work with the data on multiple levels to find novel relationships between the query and retrieval set members. Space constraints prohibit addressing all aspects of this project. PMID:11079845

Evidence-based Effective Triage Operation During Disaster: Application of Human-trajectory Data to Triage Drill Sessions.

PubMed

Ohta, Shoichi; Yoda, Ikushi; Takeda, Munekazu; Kuroshima, Satomi; Uchida, Kotaro; Kawai, Kentaro; Yukioka, Tetsuo

2015-02-01

Though many governmental and nongovernmental efforts for disaster prevention have been sought throughout Japan since the Great East Japan Earthquake on March 11, 2011, most of the preparation efforts for disasters have been based more on structural and conventionalized regulations than on scientific and objective grounds. Problem There has been a lack of scientific knowledge for space utilization for triage posts in disaster drill sessions. This report addresses how participants occupy and make use of the space within a triage post in terms of areas of use and occupied time. The trajectories of human movement by using Ubiquitous Stereo Vision (USV) cameras during two emergency drill sessions held in 2012 in a large commercial building have been measured. The USV cameras collect each participant's travel distance and the wait time before, during, and after undergoing triage. The correlation between the wait time and the space utilization of patients at a triage post has been analyzed. In the first session, there were some spaces not entirely used. This was caused largely by a patient who arrived earlier than others and lingered in the middle area, which caused the later arrivals to crowd the entrance area. On the other hand, in the second session, the area was used in a more evenly-distributed manner. This is mainly because the earlier arrivals were guided to the back space of the triage post (ie, the opposite side of the entrance), and the late arrivals were also guided to the front half, which was not occupied by anyone. As a result, the entire space was effectively utilized without crowding the entrance. This study has shown that this system could measure people's arrival times and the speed of their movements at the triage post, as well as where they are placed until they receive triage. Space utilization can be improved by efficiently planning and controlling the positioning of arriving patients. Based on the results, it has been suggested that for triage operation, it is necessary to efficiently plan and control the placement of patients in order to use strategically limited spatial resources.

Insight and search in Katona's five-square problem.

PubMed

Ollinger, Michael; Jones, Gary; Knoblich, Günther

2014-01-01

Insights are often productive outcomes of human thinking. We provide a cognitive model that explains insight problem solving by the interplay of problem space search and representational change, whereby the problem space is constrained or relaxed based on the problem representation. By introducing different experimental conditions that either constrained the initial search space or helped solvers to initiate a representational change, we investigated the interplay of problem space search and representational change in Katona's five-square problem. Testing 168 participants, we demonstrated that independent hints relating to the initial search space and to representational change had little effect on solution rates. However, providing both hints caused a significant increase in solution rates. Our results show the interplay between problem space search and representational change in insight problem solving: The initial problem space can be so large that people fail to encounter impasse, but even when representational change is achieved the resulting problem space can still provide a major obstacle to finding the solution.

Space research - At a crossroads

NASA Technical Reports Server (NTRS)

Mcdonald, Frank B.

1987-01-01

Efforts which must be expended if U.S. space research is to regain vitality in the next few years are discussed. Small-scale programs are the cornerstone for big science projects, giving both researchers and students a chance to practice the development of space missions and hardware and identify promising goals for larger projects. Small projects can be carried aloft by balloons, sounding rockets, the Shuttle and ELVs. It is recommended that NASA continue the development of remote sensing systems, and join with other government agencies to fund space-based materials science, space biology and medical research. Increased international cooperation in space projects is necessary for affording moderate to large scale missions, for political reasons, and to maximize available space resources. Finally, the establishment and funding of long-range goals in space, particularly the development of the infrastructure and technologies for the exploration and colonization of the planets, must be viewed as the normal outgrowth of the capabilities being developed for LEO operations.

Physical sciences research plans for the International Space Station.

PubMed

Trinh, E H

2003-01-01

The restructuring of the research capabilities of the International Space Station has forced a reassessment of the Physical Sciences research plans and a re-targeting of the major scientific thrusts. The combination of already selected peer-reviewed flight investigations with the initiation of new research and technology programs will allow the maximization of the ISS scientific and technological potential. Fundamental and applied research will use a combination of ISS-based facilities, ground-based activities, and other experimental platforms to address issues impacting fundamental knowledge, industrial and medical applications on Earth, and the technology required for human space exploration. The current flight investigation research plan shows a large number of principal investigators selected to use the remaining planned research facilities. c2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved.

Physical sciences research plans for the International Space Station

NASA Technical Reports Server (NTRS)

Trinh, E. H.

2003-01-01

The restructuring of the research capabilities of the International Space Station has forced a reassessment of the Physical Sciences research plans and a re-targeting of the major scientific thrusts. The combination of already selected peer-reviewed flight investigations with the initiation of new research and technology programs will allow the maximization of the ISS scientific and technological potential. Fundamental and applied research will use a combination of ISS-based facilities, ground-based activities, and other experimental platforms to address issues impacting fundamental knowledge, industrial and medical applications on Earth, and the technology required for human space exploration. The current flight investigation research plan shows a large number of principal investigators selected to use the remaining planned research facilities. c2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved.

Early use of Space Station Freedom for NASA's Microgravity Science and Applications Program

NASA Technical Reports Server (NTRS)

Rhome, Robert C.; O'Malley, Terence F.

1992-01-01

The paper describes microgravity science opportunities inherent to the restructured Space Station and presents a synopsis of the scientific utilization plan for the first two years of ground-tended operations. In the ground-tended utilization mode the Space Station is a large free-flyer providing a continuous microgravity environment unmatched by any other platform within any existing U.S. program. It is pointed out that the importance of this period of early Space Station mixed-mode utilization between crew-tended and ground-tended approaches is of such magnitude that Station-based microgravity science experiments many become benchmarks to the disciplines involved. The traffic model that is currently being pursued is designed to maximize this opportunity for the U.S. microgravity science community.

Key issues in space nuclear power challenges for the future

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W., Jr.

1991-01-01

The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. Key to the success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience has been made. These needs fall into three broad categories: survival, self sufficiency, and industrialization. The cost of delivering payloads to orbital locations from LEO to Mars has been determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options has been made. These goals are largely dependent upon orbital location and energy storage needs. Finally the cost of present space power systems has been determined and projections made for future systems.

Key issues in space nuclear power

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W.

1991-01-01

The future appears rich in missions that will extend the frontiers of knowledge, human presence in space, and opportunities for profitable commerce. Key to the success of these ventures is the availability of plentiful, cost effective electric power and assured, low cost access to space. While forecasts of space power needs are problematic, an assessment of future needs based on terrestrial experience has been made. These needs fall into three broad categories: survival, self sufficiency, and industrialization. The cost of delivering payloads to orbital locations from LEO to Mars has been determined and future launch cost reductions projected. From these factors, then, projections of the performance necessary for future solar and nuclear space power options has been made. These goals are largely dependent upon orbital location and energy storage needs. Finally the cost of present space power systems has been determined and projections made for future systems.

An Integrated, Optimization-Based Approach to the Design and Control of Large Space Structures.

DTIC Science & Technology

1984-05-01

investigator.s shall use a nonlinear beam model for the large motions, and they shall use a linear beam model to describe the small displacements as a... use a nonlinear beam model for the large motions, and we shall use a linear beam model to describe the small displacements as a perturbation around the...of the angular velocity, wt as follows 0 = 0 - 0 (2. ) -01 G,𔃼 - f- 0. The use of a quaternion avoids singularities which are often encountered in

Accurate low-cost methods for performance evaluation of cache memory systems

NASA Technical Reports Server (NTRS)

Laha, Subhasis; Patel, Janak H.; Iyer, Ravishankar K.

1988-01-01

Methods of simulation based on statistical techniques are proposed to decrease the need for large trace measurements and for predicting true program behavior. Sampling techniques are applied while the address trace is collected from a workload. This drastically reduces the space and time needed to collect the trace. Simulation techniques are developed to use the sampled data not only to predict the mean miss rate of the cache, but also to provide an empirical estimate of its actual distribution. Finally, a concept of primed cache is introduced to simulate large caches by the sampling-based method.

Space-based infrared near-Earth asteroid survey simulation

NASA Astrophysics Data System (ADS)

Tedesco, Edward F.; Muinonen, Karri; Price, Stephan D.

2000-08-01

We demonstrate the efficiency and effectiveness of using a satellite-based sensor with visual and infrared focal plane arrays to search for that subclass of Near-Earth Objects (NEOs) with orbits largely interior to the Earth's orbit. A space-based visual-infrared system could detect approximately 97% of the Atens and 64% of the IEOs (the, as yet hypothetical, objects with orbits entirely Interior to Earth's Orbit) with diameters greater than 1 km in a 5-year mission and obtain orbits, albedos and diameters for all of them; the respective percentages with diameters greater than 500 m are 90% and 60%. Incidental to the search for Atens and IEOs, we found that 70% of all Earth-Crossing Asteroids (ECAs) with diameters greater than 1 km, and 50% of those with diameters greater than 500 m, would also be detected. These are the results of a feasibility study; optimizing the concept presented would result in greater levels of completion. The cost of such a space-based system is estimated to be within a factor of two of the cost of a ground-based system capable of about 21st magnitude, which would provide only orbits and absolute magnitudes and require decades to reach these completeness levels. In addition to obtaining albedos and diameters for the asteroids discovered in the space-based survey, a space-based visual-infrared system would obtain the same information on virtually all NEOs of interest. A combined space-based and ground-based survey would be highly synergistic in that each can concentrate on what it does best and each complements the strengths of the other. The ground-based system would discover the majority of Amors and Apollos and provide long-term follow-up on all the NEOs discovered in both surveys. The space-based system would discover the majority of Atens and IEOs and provide albedos and diameters on all the NEOs discovered in both surveys and most previously discovered NEOs as well. Thus, an integrated ground- and space-based system could accomplish the Spaceguard goal in less time than the ground-based system alone. In addition, the result would be a catalog containing well-determined orbits, diameters, and albedos for the majority of ECAs with diameters greater than 500 m.

Optical linear algebra processors - Architectures and algorithms

NASA Technical Reports Server (NTRS)

Casasent, David

1986-01-01

Attention is given to the component design and optical configuration features of a generic optical linear algebra processor (OLAP) architecture, as well as the large number of OLAP architectures, number representations, algorithms and applications encountered in current literature. Number-representation issues associated with bipolar and complex-valued data representations, high-accuracy (including floating point) performance, and the base or radix to be employed, are discussed, together with case studies on a space-integrating frequency-multiplexed architecture and a hybrid space-integrating and time-integrating multichannel architecture.

Deep convolutional neural networks as strong gravitational lens detectors

NASA Astrophysics Data System (ADS)

Schaefer, C.; Geiger, M.; Kuntzer, T.; Kneib, J.-P.

2018-03-01

Context. Future large-scale surveys with high-resolution imaging will provide us with approximately 105 new strong galaxy-scale lenses. These strong-lensing systems will be contained in large data amounts, however, which are beyond the capacity of human experts to visually classify in an unbiased way. Aim. We present a new strong gravitational lens finder based on convolutional neural networks (CNNs). The method was applied to the strong-lensing challenge organized by the Bologna Lens Factory. It achieved first and third place, respectively, on the space-based data set and the ground-based data set. The goal was to find a fully automated lens finder for ground-based and space-based surveys that minimizes human inspection. Methods: We compared the results of our CNN architecture and three new variations ("invariant" "views" and "residual") on the simulated data of the challenge. Each method was trained separately five times on 17 000 simulated images, cross-validated using 3000 images, and then applied to a test set with 100 000 images. We used two different metrics for evaluation, the area under the receiver operating characteristic curve (AUC) score, and the recall with no false positive (Recall0FP). Results: For ground-based data, our best method achieved an AUC score of 0.977 and a Recall0FP of 0.50. For space-based data, our best method achieved an AUC score of 0.940 and a Recall0FP of 0.32. Adding dihedral invariance to the CNN architecture diminished the overall score on space-based data, but achieved a higher no-contamination recall. We found that using committees of five CNNs produced the best recall at zero contamination and consistently scored better AUC than a single CNN. Conclusions: We found that for every variation of our CNN lensfinder, we achieved AUC scores close to 1 within 6%. A deeper network did not outperform simpler CNN models either. This indicates that more complex networks are not needed to model the simulated lenses. To verify this, more realistic lens simulations with more lens-like structures (spiral galaxies or ring galaxies) are needed to compare the performance of deeper and shallower networks.

Space Resource Requirements for Future In-Space Propellant Production Depots

NASA Technical Reports Server (NTRS)

Smitherman, David; Fikes, John; Roy, Stephanie; Henley, Mark W.; Potter, Seth D.; Howell, Joe T. (Technical Monitor)

2001-01-01

In 2000 and 2001 studies were conducted at the NASA Marshall Space Flight Center on the technical requirements and commercial potential for propellant production depots in low Earth orbit (LEO) to support future commercial, NASA, and other Agency missions. Results indicate that propellant production depots appear to be technically feasible given continued technology development, and there is a substantial growing market that depots could support. Systems studies showed that the most expensive part of transferring payloads to geosynchronous orbit (GEO) is the fuel. A cryogenic propellant production and storage depot stationed in LEO could lower the cost of missions to GEO and beyond. Propellant production separates water into hydrogen and oxygen through electrolysis. This process utilizes large amounts of power, therefore a depot derived from advanced space solar power technology was defined. Results indicate that in the coming decades there could be a significant demand for water-based propellants from Earth, moon, or asteroid resources if in-space transfer vehicles (upper stages) transitioned to reusable systems using water based propellants. This type of strategic planning move could create a substantial commercial market for space resources development, and ultimately lead toward significant commercial infrastructure development within the Earth-Moon system.

Why Atens Enjoy Enhanced Accessibility for Human Space Flight

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Adamo, Daniel R.

2011-01-01

Near-Earth objects can be grouped into multiple orbit classifications, among them being the Aten group, whose members have orbits crossing Earth's with semi-major axes less than 1 astronomical unit. Atens comprise well under 10% of known near-Earth objects. This is in dramatic contrast to results from recent human space flight near-Earth object accessibility studies, where the most favorable known destinations are typically almost 50% Atens. Geocentric dynamics explain this enhanced Aten accessibility and lead to an understanding of where the most accessible near-Earth objects reside. Without a comprehensive space-based survey, however, highly accessible Atens will remain largely unknown.

Multidisciplinary optimization of a controlled space structure using 150 design variables

NASA Technical Reports Server (NTRS)

James, Benjamin B.

1992-01-01

A general optimization-based method for the design of large space platforms through integration of the disciplines of structural dynamics and control is presented. The method uses the global sensitivity equations approach and is especially appropriate for preliminary design problems in which the structural and control analyses are tightly coupled. The method is capable of coordinating general purpose structural analysis, multivariable control, and optimization codes, and thus, can be adapted to a variety of controls-structures integrated design projects. The method is used to minimize the total weight of a space platform while maintaining a specified vibration decay rate after slewing maneuvers.

Feature integration across space, time, and orientation

PubMed Central

Otto, Thomas U.; Öğmen, Haluk; Herzog, Michael H.

2012-01-01

The perception of a visual target can be strongly influenced by flanking stimuli. In static displays, performance on the target improves when the distance to the flanking elements increases- proposedly because feature pooling and integration vanishes with distance. Here, we studied feature integration with dynamic stimuli. We show that features of single elements presented within a continuous motion stream are integrated largely independent of spatial distance (and orientation). Hence, space based models of feature integration cannot be extended to dynamic stimuli. We suggest that feature integration is guided by perceptual grouping operations that maintain the identity of perceptual objects over space and time. PMID:19968428

LOBSTER: new space x-ray telescopes

NASA Astrophysics Data System (ADS)

Hudec, R.; Sveda, L.; Pína, L.; Inneman, A.; Semencova, V.; Skulinova, M.

2017-11-01

The LOBSTER telescopes are based on the optical arrangement of the lobster eye. The main difference from classical X-ray space telescopes in wide use is the very large field of view while the use of optics results in higher efficiency if compared with detectors without optics. Recent innovative technologies have enabled to design, to develop and to test first prototypes. They will provide deep sensitive survey of the sky in X-rays for the first time which is essential for both long-term monitoring of celestial high-energy sources as well as in understanding transient phenomena. The technology is now ready for applications in space.

Space solar power - An energy alternative

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1978-01-01

The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.

Terrestrial photovoltaic collector technology trends

NASA Technical Reports Server (NTRS)

Shimada, K.; Costogue, E.

1984-01-01

Following the path of space PV collector development in its early stages, terrestrial PV technologies based upon single-crystal silicon have matured rapidly. Currently, terrestrial PV cells with efficiencies approaching space cell efficiencies are being fabricated into modules at a fraction of the space PV module cost. New materials, including CuInSe2 and amorphous silicon, are being developed for lowering the cost, and multijunction materials for achieving higher efficiency. Large grid-interactive, tracking flat-plate power systems and concentrator PV systems totaling about 10 MW, are already in operation. Collector technology development both flat-plate and concentrator, will continue under an extensive government and private industry partnership.

Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

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

Saheed, M. Shuaib M.; Muti Mohamed, Norani; Arif Burhanudin, Zainal, E-mail: zainabh@petronas.com.my

2014-03-24

Ionization gas sensors using vertically aligned multi-wall carbon nanotubes (MWCNT) are demonstrated. The sharp tips of the nanotubes generate large non-uniform electric fields at relatively low applied voltage. The enhancement of the electric field results in field emission of electrons that dominates the breakdown mechanism in gas sensor with gap spacing below 14 μm. More than 90% reduction in breakdown voltage is observed for sensors with MWCNT and 7 μm gap spacing. Transition of breakdown mechanism, dominated by avalanche electrons to field emission electrons, as decreasing gap spacing is also observed and discussed.

Spacecraft momentum management procedures. [large space telescope

NASA Technical Reports Server (NTRS)

Chen, L. C.; Davenport, P. B.; Sturch, C. R.

1980-01-01

Techniques appropriate for implementation onboard the space telescope and other spacecraft to manage the accumulation of momentum in reaction wheel control systems using magnetic torquing coils are described. Generalized analytical equations are derived for momentum control laws that command the magnetic torquers. These control laws naturally fall into two main categories according to the methods used for updating the magnetic dipole command: closed loop, in which the update is based on current measurements to achieve a desired torque instantaneously, and open-loop, in which the update is based on predicted information to achieve a desired momentum at the end of a period of time. Physical interpretations of control laws in general and of the Space Telescope cross product and minimum energy control laws in particular are presented, and their merits and drawbacks are discussed. A technique for retaining the advantages of both the open-loop and the closed-loop control laws is introduced. Simulation results are presented to compare the performance of these control laws in the Space Telescope environment.

Microgravity Effects on Microbiology In Space Laboratories

NASA Technical Reports Server (NTRS)

Nelson, Emily S.; Juergensmeyer, Elizabeth; Juergensmeyer, Margaret

2000-01-01

Here we present a review of the effects of residual acceleration on microorganisms in space Laboratories. Residual acceleration in the microgravity environment is frequently ignored by microbiologists, although their experiments may be as sensitive to this acceleration as those designed by materials scientists and fluid physicists. Furthermore, analysis to date has been largely empirical and/or based on very simple theoretical models. As a result, the responses of single cells to the space environment are widely assumed to be taking place in "pure" microgravity. These responses vary widely and are not well understood. Some of this variation may be due to the range of microgravity conditions experience by organisms. In the future, as we move from visiting orbital environments to living and working there, we will undoubtedly bring microorganisms with us. It is also quite likely that the first extraterrestrial life we encounter will be single-celled organisms. Therefore, we would like to present a summary of the current knowledge base, and to challenge the space community to develop new approaches in understanding this important field.

Development, Testing and Operation of a Large Suspended Ocean Measurement Structure for Deep-Ocean Use

DTIC Science & Technology

1992-05-01

and systems for developing , testing, and operating the system. A new, lightweight cable de- used this evolving technology base in the ensuing years...Funding Numbers. Development , Testing, and Operation of a Large Suspended Ocean Contrac Measurement Structure for Deep-Ocean Use Program Element No...Research L.aboratory Report Number. Ocean Acoutics and Technology Directorate PR 91:132:253 Stennis Space Center, MS 39529-5004 9. Sponsoring

Space Industrialization: The Mirage of Abundance.

ERIC Educational Resources Information Center

Deudney, Daniel

1982-01-01

Large-scale space industrialization is not a viable solution to the population, energy, and resource problems of earth. The expense and technological difficulties involved in the development and maintenance of space manufacturing facilities, space colonies, and large-scale satellites for solar power are discussed. (AM)

Space construction system analysis. Part 2: Space construction experiments concepts

NASA Technical Reports Server (NTRS)

Boddy, J. A.; Wiley, L. F.; Gimlich, G. W.; Greenberg, H. S.; Hart, R. J.; Lefever, A. E.; Lillenas, A. N.; Totah, R. S.

1980-01-01

Technology areas in the orbital assembly of large space structures are addressed. The areas included structures, remotely operated assembly techniques, and control and stabilization. Various large space structure design concepts are reviewed and their construction procedures and requirements are identified.

An adaptive process-based cloud infrastructure for space situational awareness applications

NASA Astrophysics Data System (ADS)

Liu, Bingwei; Chen, Yu; Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik; Rubin, Bruce

2014-06-01

Space situational awareness (SSA) and defense space control capabilities are top priorities for groups that own or operate man-made spacecraft. Also, with the growing amount of space debris, there is an increase in demand for contextual understanding that necessitates the capability of collecting and processing a vast amount sensor data. Cloud computing, which features scalable and flexible storage and computing services, has been recognized as an ideal candidate that can meet the large data contextual challenges as needed by SSA. Cloud computing consists of physical service providers and middleware virtual machines together with infrastructure, platform, and software as service (IaaS, PaaS, SaaS) models. However, the typical Virtual Machine (VM) abstraction is on a per operating systems basis, which is at too low-level and limits the flexibility of a mission application architecture. In responding to this technical challenge, a novel adaptive process based cloud infrastructure for SSA applications is proposed in this paper. In addition, the details for the design rationale and a prototype is further examined. The SSA Cloud (SSAC) conceptual capability will potentially support space situation monitoring and tracking, object identification, and threat assessment. Lastly, the benefits of a more granular and flexible cloud computing resources allocation are illustrated for data processing and implementation considerations within a representative SSA system environment. We show that the container-based virtualization performs better than hypervisor-based virtualization technology in an SSA scenario.

A near term space demonstration program for large structures

NASA Technical Reports Server (NTRS)

Nathan, C. A.

1978-01-01

For applications involving an employment of ultralarge structures in space, it would be necessary to have some form of space fabrication and assembly in connection with launch vehicle payload and volume limitations. The findings of a recently completed NASA sponsored study related to an orbital construction demonstration are reported. It is shown how a relatively small construction facility which is assembled in three shuttle flights can substantially advance space construction know-how and provide the nation with a permanent shuttle tended facility that can further advance large structures technologies and provide a construction capability for deployment of large structural systems envisioned for the late 1980s. The large structures applications identified are related to communications, navigation, earth observation, energy systems, radio astronomy, illumination, space colonization, and space construction.

Biased Tracers in Redshift Space in the EFT of Large-Scale Structure

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

Perko, Ashley; Senatore, Leonardo; Jennings, Elise

2016-10-28

The Effective Field Theory of Large-Scale Structure (EFTofLSS) provides a novel formalism that is able to accurately predict the clustering of large-scale structure (LSS) in the mildly non-linear regime. Here we provide the first computation of the power spectrum of biased tracers in redshift space at one loop order, and we make the associated code publicly available. We compare the multipolesmore » $$\\ell=0,2$$ of the redshift-space halo power spectrum, together with the real-space matter and halo power spectra, with data from numerical simulations at $z=0.67$. For the samples we compare to, which have a number density of $$\\bar n=3.8 \\cdot 10^{-2}(h \\ {\\rm Mpc}^{-1})^3$$ and $$\\bar n=3.9 \\cdot 10^{-4}(h \\ {\\rm Mpc}^{-1})^3$$, we find that the calculation at one-loop order matches numerical measurements to within a few percent up to $$k\\simeq 0.43 \\ h \\ {\\rm Mpc}^{-1}$$, a significant improvement with respect to former techniques. By performing the so-called IR-resummation, we find that the Baryon Acoustic Oscillation peak is accurately reproduced. Based on the results presented here, long-wavelength statistics that are routinely observed in LSS surveys can be finally computed in the EFTofLSS. This formalism thus is ready to start to be compared directly to observational data.« less

Last results of technological developments for ultra-lightweight, large aperture, deployable mirror for space telescopes

NASA Astrophysics Data System (ADS)

Gambicorti, Lisa; D'Amato, Francesco; Vettore, Christian; Duò, Fabrizio; Guercia, Alessio; Patauner, Christian; Biasi, Roberto; Lisi, Franco; Riccardi, Armando; Gallieni, Daniele; Lazzarini, Paolo; Tintori, Matteo; Zuccaro Marchi, Alessandro; Pereira do Carmo, Joao

2017-11-01

The aim of this work is to describe the latest results of new technological concepts for Large Aperture Telescopes Technology (LATT) using thin deployable lightweight active mirrors. This technology is developed under the European Space Agency (ESA) Technology Research Program and can be exploited in all the applications based on the use of primary mirrors of space telescopes with large aperture, segmented lightweight telescopes with wide Field of View (FOV) and low f/#, and LIDAR telescopes. The reference mission application is a potential future ESA mission, related to a space borne DIAL (Differential Absorption Lidar) instrument operating around 935.5 nm with the goal to measure water vapor profiles in atmosphere. An Optical BreadBoard (OBB) for LATT has been designed for investigating and testing two critical aspects of the technology: 1) control accuracy in the mirror surface shaping. 2) mirror survivability to launch. The aim is to evaluate the effective performances of the long stroke smart-actuators used for the mirror control and to demonstrate the effectiveness and the reliability of the electrostatic locking (EL) system to restraint the thin shell on the mirror backup structure during launch. The paper presents a comprehensive vision of the breadboard focusing on how the requirements have driven the design of the whole system and of the various subsystems. The manufacturing process of the thin shell is also presented.

Simulation of reflecting surface deviations of centimeter-band parabolic space radiotelescope (SRT) with the large-size mirror

NASA Astrophysics Data System (ADS)

Kotik, A.; Usyukin, V.; Vinogradov, I.; Arkhipov, M.

2017-11-01

he realization of astrophysical researches requires the development of high-sensitive centimeterband parabolic space radiotelescopes (SRT) with the large-size mirrors. Constructively such SRT with the mirror size more than 10 m can be realized as deployable rigid structures. Mesh-structures of such size do not provide the reflector reflecting surface accuracy which is necessary for the centimeter band observations. Now such telescope with the 10 m diameter mirror is developed in Russia in the frame of "SPECTR - R" program. External dimensions of the telescope is more than the size of existing thermo-vacuum chambers used to prove SRT reflecting surface accuracy parameters under the action of space environment factors. That's why the numerical simulation turns out to be the basis required to accept the taken designs. Such modeling should be based on experimental working of the basic constructive materials and elements of the future reflector. In the article computational modeling of reflecting surface deviations of a centimeter-band of a large-sized deployable space reflector at a stage of his orbital functioning is considered. The analysis of the factors that determines the deviations - both determined (temperatures fields) and not-determined (telescope manufacturing and installation faults; the deformations caused by features of composite materials behavior in space) is carried out. The finite-element model and complex of methods are developed. They allow to carry out computational modeling of reflecting surface deviations caused by influence of all factors and to take into account the deviations correction by space vehicle orientation system. The results of modeling for two modes of functioning (orientation at the Sun) SRT are presented.

Free-decay time-domain modal identification for large space structures

NASA Technical Reports Server (NTRS)

Kim, Hyoung M.; Vanhorn, David A.; Doiron, Harold H.

1992-01-01

Concept definition studies for the Modal Identification Experiment (MIE), a proposed space flight experiment for the Space Station Freedom (SSF), have demonstrated advantages and compatibility of free-decay time-domain modal identification techniques with the on-orbit operational constraints of large space structures. Since practical experience with modal identification using actual free-decay responses of large space structures is very limited, several numerical and test data reduction studies were conducted. Major issues and solutions were addressed, including closely-spaced modes, wide frequency range of interest, data acquisition errors, sampling delay, excitation limitations, nonlinearities, and unknown disturbances during free-decay data acquisition. The data processing strategies developed in these studies were applied to numerical simulations of the MIE, test data from a deployable truss, and launch vehicle flight data. Results of these studies indicate free-decay time-domain modal identification methods can provide accurate modal parameters necessary to characterize the structural dynamics of large space structures.

Simultaneous in-plane and out-of-plane displacement measurement based on a dual-camera imaging system and its application to inspection of large-scale space structures

NASA Astrophysics Data System (ADS)

Ri, Shien; Tsuda, Hiroshi; Yoshida, Takeshi; Umebayashi, Takashi; Sato, Akiyoshi; Sato, Eiichi

2015-07-01

Optical methods providing full-field deformation data have potentially enormous interest for mechanical engineers. In this study, an in-plane and out-of-plane displacement measurement method based on a dual-camera imaging system is proposed. The in-plane and out-of-plane displacements are determined simultaneously using two measured in-plane displacement data observed from two digital cameras at different view angles. The fundamental measurement principle and experimental results of accuracy confirmation are presented. In addition, we applied this method to the displacement measurement in a static loading and bending test of a solid rocket motor case (CFRP material; 2.2 m diameter and 2.3 m long) for an up-to-date Epsilon rocket developed by JAXA. The effectiveness and measurement accuracy is confirmed by comparing with conventional displacement sensor. This method could be useful to diagnose the reliability of large-scale space structures in the rocket development.

Fast computation of quadrupole and hexadecapole approximations in microlensing with a single point-source evaluation

NASA Astrophysics Data System (ADS)

Cassan, Arnaud

2017-07-01

The exoplanet detection rate from gravitational microlensing has grown significantly in recent years thanks to a great enhancement of resources and improved observational strategy. Current observatories include ground-based wide-field and/or robotic world-wide networks of telescopes, as well as space-based observatories such as satellites Spitzer or Kepler/K2. This results in a large quantity of data to be processed and analysed, which is a challenge for modelling codes because of the complexity of the parameter space to be explored and the intensive computations required to evaluate the models. In this work, I present a method that allows to compute the quadrupole and hexadecapole approximations of the finite-source magnification with more efficiency than previously available codes, with routines about six times and four times faster, respectively. The quadrupole takes just about twice the time of a point-source evaluation, which advocates for generalizing its use to large portions of the light curves. The corresponding routines are available as open-source python codes.

Tunable, Highly Stable Lasers for Coherent Lidar

NASA Technical Reports Server (NTRS)

Henderson, Sammy W.; Hale, Charley P.; EEpagnier, David M.

2006-01-01

Practical space-based coherent laser radar systems envisioned for global winds measurement must be very efficient and must contend with unique problems associated with the large platform velocities that the instruments experience in orbit. To compensate for these large platform-induced Doppler shifts in space-based applications, agile-frequency offset-locking of two single-frequency Doppler reference lasers was thoroughly investigated. Such techniques involve actively locking a frequency-agile master oscillator (MO) source to a comparatively static local oscillator (LO) laser, and effectively producing an offset between MO (the lidar slave oscillator seed source, typically) and heterodyne signal receiver LO that lowers the bandwidth of the receiver data-collection system and permits use of very high-quantum-efficiency, reasonably- low-bandwidth heterodyne photoreceiver detectors and circuits. Recent work on MO/LO offset locking has focused on increasing the offset locking range, improving the graded-InGaAs photoreceiver performance, and advancing the maturity of the offset locking electronics. A figure provides a schematic diagram of the offset-locking system.

A precise method for adjusting the optical system of laser sub-aperture

NASA Astrophysics Data System (ADS)

Song, Xing; Zhang, Xue-min; Yang, Jianfeng; Xue, Li

2018-02-01

In order to adapt to the requirement of modern astronomical observation and warfare, the resolution of the space telescope is needed to improve, sub-aperture stitching imaging technique is one method to improve the resolution, which could be used not only the foundation and space-based large optical systems, also used in laser transmission and microscopic imaging. A large aperture main mirror of sub-aperture stitching imaging system is composed of multiple sub-mirrors distributed according to certain laws. All sub-mirrors are off-axis mirror, so the alignment of sub-aperture stitching imaging system is more complicated than a single off-axis optical system. An alignment method based on auto-collimation imaging and interferometric imaging is introduced in this paper, by using this alignment method, a sub-aperture stitching imaging system which is composed of 12 sub-mirrors was assembled with high resolution, the beam coincidence precision is better than 0.01mm, and the system wave aberration is better than 0.05λ.

DataWarrior: an open-source program for chemistry aware data visualization and analysis.

PubMed

Sander, Thomas; Freyss, Joel; von Korff, Modest; Rufener, Christian

2015-02-23

Drug discovery projects in the pharmaceutical industry accumulate thousands of chemical structures and ten-thousands of data points from a dozen or more biological and pharmacological assays. A sufficient interpretation of the data requires understanding, which molecular families are present, which structural motifs correlate with measured properties, and which tiny structural changes cause large property changes. Data visualization and analysis software with sufficient chemical intelligence to support chemists in this task is rare. In an attempt to contribute to filling the gap, we released our in-house developed chemistry aware data analysis program DataWarrior for free public use. This paper gives an overview of DataWarrior's functionality and architecture. Exemplarily, a new unsupervised, 2-dimensional scaling algorithm is presented, which employs vector-based or nonvector-based descriptors to visualize the chemical or pharmacophore space of even large data sets. DataWarrior uses this method to interactively explore chemical space, activity landscapes, and activity cliffs.

Plate-based diversity subset screening: an efficient paradigm for high throughput screening of a large screening file.

PubMed

Bell, Andrew S; Bradley, Joseph; Everett, Jeremy R; Knight, Michelle; Loesel, Jens; Mathias, John; McLoughlin, David; Mills, James; Sharp, Robert E; Williams, Christine; Wood, Terence P

2013-05-01

The screening files of many large companies, including Pfizer, have grown considerably due to internal chemistry efforts, company mergers and acquisitions, external contracted synthesis, or compound purchase schemes. In order to screen the targets of interest in a cost-effective fashion, we devised an easy-to-assemble, plate-based diversity subset (PBDS) that represents almost the entire computed chemical space of the screening file whilst comprising only a fraction of the plates in the collection. In order to create this file, we developed new design principles for the quality assessment of screening plates: the Rule of 40 (Ro40) and a plate selection process that insured excellent coverage of both library chemistry and legacy chemistry space. This paper describes the rationale, design, construction, and performance of the PBDS, that has evolved into the standard paradigm for singleton (one compound per well) high-throughput screening in Pfizer since its introduction in 2006.

Efficient path-based computations on pedigree graphs with compact encodings

PubMed Central

2012-01-01

A pedigree is a diagram of family relationships, and it is often used to determine the mode of inheritance (dominant, recessive, etc.) of genetic diseases. Along with rapidly growing knowledge of genetics and accumulation of genealogy information, pedigree data is becoming increasingly important. In large pedigree graphs, path-based methods for efficiently computing genealogical measurements, such as inbreeding and kinship coefficients of individuals, depend on efficient identification and processing of paths. In this paper, we propose a new compact path encoding scheme on large pedigrees, accompanied by an efficient algorithm for identifying paths. We demonstrate the utilization of our proposed method by applying it to the inbreeding coefficient computation. We present time and space complexity analysis, and also manifest the efficiency of our method for evaluating inbreeding coefficients as compared to previous methods by experimental results using pedigree graphs with real and synthetic data. Both theoretical and experimental results demonstrate that our method is more scalable and efficient than previous methods in terms of time and space requirements. PMID:22536898

A Fast Method for Embattling Optimization of Ground-Based Radar Surveillance Network

NASA Astrophysics Data System (ADS)

Jiang, H.; Cheng, H.; Zhang, Y.; Liu, J.

A growing number of space activities have created an orbital debris environment that poses increasing impact risks to existing space systems and human space flight. For the safety of in-orbit spacecraft, a lot of observation facilities are needed to catalog space objects, especially in low earth orbit. Surveillance of Low earth orbit objects are mainly rely on ground-based radar, due to the ability limitation of exist radar facilities, a large number of ground-based radar need to build in the next few years in order to meet the current space surveillance demands. How to optimize the embattling of ground-based radar surveillance network is a problem to need to be solved. The traditional method for embattling optimization of ground-based radar surveillance network is mainly through to the detection simulation of all possible stations with cataloged data, and makes a comprehensive comparative analysis of various simulation results with the combinational method, and then selects an optimal result as station layout scheme. This method is time consuming for single simulation and high computational complexity for the combinational analysis, when the number of stations increases, the complexity of optimization problem will be increased exponentially, and cannot be solved with traditional method. There is no better way to solve this problem till now. In this paper, target detection procedure was simplified. Firstly, the space coverage of ground-based radar was simplified, a space coverage projection model of radar facilities in different orbit altitudes was built; then a simplified objects cross the radar coverage model was established according to the characteristics of space objects orbit motion; after two steps simplification, the computational complexity of the target detection was greatly simplified, and simulation results shown the correctness of the simplified results. In addition, the detection areas of ground-based radar network can be easily computed with the simplified model, and then optimized the embattling of ground-based radar surveillance network with the artificial intelligent algorithm, which can greatly simplifies the computational complexities. Comparing with the traditional method, the proposed method greatly improved the computational efficiency.

Towards human exploration of space: the THESEUS review series on neurophysiology research priorities.

PubMed

White, Olivier; Clément, Gilles; Fortrat, Jacques-Olivier; Pavy-LeTraon, Anne; Thonnard, Jean-Louis; Blanc, Stéphane; Wuyts, Floris L; Paloski, William H

2016-01-01

The THESEUS project (Towards Human Exploration of Space: a European Strategy), initiated within the seventh Framework Programme by the European Commission, aimed at providing a cross-cutting, life-science-based roadmap for Europe's strategy towards human exploration of long space missions, and its relevance to applications on Earth. This topic was investigated by experts in the field, in the framework of the THESEUS project whose aim was to develop an integrated life sciences research roadmap regarding human space exploration. In particular, decades of research have shown that altered gravity impairs neurological responses at large, such as perception, sleep, motor control, and cognitive factors. International experts established a list of key issues that should be addressed in that context and provided several recommendations such as a maximal exploitation of currently available resources on Earth and in space.

Particle astronomy and particle physics from the moon - The particle observatory

NASA Technical Reports Server (NTRS)

Wilson, Thomas L.

1990-01-01

Promising experiments from the moon using particle detectors are discussed, noting the advantage of the large flux collecting power Pc offered by the remote, stable environment of a lunar base. An observatory class of particle experiments is presented, based upon proposals at NASA's recent Stanford workshop. They vary from neutrino astronomy, particle astrophysics, and cosmic ray experiments to space physics and fundamental physics experiments such as proton decay and 'table-top' arrays. This research is background-limited on earth, and it is awkward and unrealistic in earth orbit, but is particularly suited for the moon where Pc can be quite large and the instrumentation is not subject to atmospheric erosion as it is (for large t) in low earth orbit.

Optimising the multiplex factor of the frequency domain multiplexed readout of the TES-based microcalorimeter imaging array for the X-IFU instrument on the Athena x-ray observatory

NASA Astrophysics Data System (ADS)

van der Kuur, J.; Gottardi, L. G.; Akamatsu, H.; van Leeuwen, B. J.; den Hartog, R.; Haas, D.; Kiviranta, M.; Jackson, B. J.

2016-07-01

Athena is a space-based X-ray observatory intended for exploration of the hot and energetic universe. One of the science instruments on Athena will be the X-ray Integrated Field Unit (X-IFU), which is a cryogenic X-ray spectrometer, based on a large cryogenic imaging array of Transition Edge Sensors (TES) based microcalorimeters operating at a temperature of 100mK. The imaging array consists of 3800 pixels providing 2.5 eV spectral resolution, and covers a field of view with a diameter of of 5 arc minutes. Multiplexed readout of the cryogenic microcalorimeter array is essential to comply with the cooling power and complexity constraints on a space craft. Frequency domain multiplexing has been under development for the readout of TES-based detectors for this purpose, not only for the X-IFU detector arrays but also for TES-based bolometer arrays for the Safari instrument of the Japanese SPICA observatory. This paper discusses the design considerations which are applicable to optimise the multiplex factor within the boundary conditions as set by the space craft. More specifically, the interplay between the science requirements such as pixel dynamic range, pixel speed, and cross talk, and the space craft requirements such as the power dissipation budget, available bandwidth, and electromagnetic compatibility will be discussed.

Space-based societal applications—Relevance in developing countries

NASA Astrophysics Data System (ADS)

Bhaskaranarayana, A.; Varadarajan, C.; Hegde, V. S.

2009-11-01

Space technology has the vast potential for addressing a variety of societal problems of the developing countries, particularly in the areas of communication, education and health sectors, land and water resources management, disaster management and weather forecasting. Both remote sensing and communication technologies can be used to achieve this goal. With its primary emphasis on application of space technology, on an end-to-end basis, towards national development, the Indian Space Programme has distinguished itself as one of the most cost-effective and development-oriented space programmes in the world. Developing nations are faced with the enormous task of carrying development-oriented education to the masses at the lower strata of their societies. One important feature of these populations is their large number and the spread over vast and remote areas of these nations, making the reaching out to them a difficult task. Satellite communication (Satcom) technology offers the unique capability of simultaneously reaching out to very large numbers, spread over vast areas, including the remote corners of the country. It is a strong tool to support development education. India has been amongst the first few nations to explore and put to use the Satcom technology for education and development-oriented services to the rural masses. Most of the developing countries have inadequate infrastructure to provide proper medical care to the rural population. Availability of specialist doctors in rural areas is a major bottleneck. Use of Satcom and information technology to connect rural clinics to urban hospitals through telemedicine systems is one of the solutions; and India has embarked upon an effective satellite-based telemedicine programme. Space technology is also useful in disaster warning and management related applications. Use of satellite systems and beacons for locating the distressed units on land, sea or air is well known to us. Indian Space Research Organisation (ISRO) is already a part of the International initiative called Satellite Aided Search and Rescue System. The programme to set up satellite-based Village Resource Centres (VRCs) across India, for providing a variety of services relevant to the rural communities, is also a unique societal application of space technology. The VRCs are envisaged as single window delivery mechanism for a variety of space-based products and services, such as tele-education; telemedicine; information on natural resources for planning and development at local level; interactive advisories on agriculture, fisheries, land and water resources management, livestock management, etc.; interactive vocational training towards alternative livelihood; e-governance; weather information; etc. This paper describes the various possibilities and potentials of Satcom and Remote Sensing technologies for societal applications. The initiatives taken by Indian Space Research Organisation in this direction are highlighted.

Hierarchical trie packet classification algorithm based on expectation-maximization clustering.

PubMed

Bi, Xia-An; Zhao, Junxia

2017-01-01

With the development of computer network bandwidth, packet classification algorithms which are able to deal with large-scale rule sets are in urgent need. Among the existing algorithms, researches on packet classification algorithms based on hierarchical trie have become an important packet classification research branch because of their widely practical use. Although hierarchical trie is beneficial to save large storage space, it has several shortcomings such as the existence of backtracking and empty nodes. This paper proposes a new packet classification algorithm, Hierarchical Trie Algorithm Based on Expectation-Maximization Clustering (HTEMC). Firstly, this paper uses the formalization method to deal with the packet classification problem by means of mapping the rules and data packets into a two-dimensional space. Secondly, this paper uses expectation-maximization algorithm to cluster the rules based on their aggregate characteristics, and thereby diversified clusters are formed. Thirdly, this paper proposes a hierarchical trie based on the results of expectation-maximization clustering. Finally, this paper respectively conducts simulation experiments and real-environment experiments to compare the performances of our algorithm with other typical algorithms, and analyzes the results of the experiments. The hierarchical trie structure in our algorithm not only adopts trie path compression to eliminate backtracking, but also solves the problem of low efficiency of trie updates, which greatly improves the performance of the algorithm.

A Principled Approach to the Specification of System Architectures for Space Missions

NASA Technical Reports Server (NTRS)

McKelvin, Mark L. Jr.; Castillo, Robert; Bonanne, Kevin; Bonnici, Michael; Cox, Brian; Gibson, Corrina; Leon, Juan P.; Gomez-Mustafa, Jose; Jimenez, Alejandro; Madni, Azad

2015-01-01

Modern space systems are increasing in complexity and scale at an unprecedented pace. Consequently, innovative methods, processes, and tools are needed to cope with the increasing complexity of architecting these systems. A key systems challenge in practice is the ability to scale processes, methods, and tools used to architect complex space systems. Traditionally, the process for specifying space system architectures has largely relied on capturing the system architecture in informal descriptions that are often embedded within loosely coupled design documents and domain expertise. Such informal descriptions often lead to misunderstandings between design teams, ambiguous specifications, difficulty in maintaining consistency as the architecture evolves throughout the system development life cycle, and costly design iterations. Therefore, traditional methods are becoming increasingly inefficient to cope with ever-increasing system complexity. We apply the principles of component-based design and platform-based design to the development of the system architecture for a practical space system to demonstrate feasibility of our approach using SysML. Our results show that we are able to apply a systematic design method to manage system complexity, thus enabling effective data management, semantic coherence and traceability across different levels of abstraction in the design chain. Just as important, our approach enables interoperability among heterogeneous tools in a concurrent engineering model based design environment.

T cell regulation in microgravity - The current knowledge from in vitro experiments conducted in space, parabolic flights and ground-based facilities

NASA Astrophysics Data System (ADS)

Hauschild, Swantje; Tauber, Svantje; Lauber, Beatrice; Thiel, Cora S.; Layer, Liliana E.; Ullrich, Oliver

2014-11-01

Dating back to the Apollo and Skylab missions, it has been reported that astronauts suffered from bacterial and viral infections during space flight or after returning to Earth. Blood analyses revealed strongly reduced capability of human lymphocytes to become active upon mitogenic stimulation. Since then, a large number of in vitro studies on human immune cells have been conducted in space, in parabolic flights, and in ground-based facilities. It became obvious that microgravity affects cell morphology and important cellular functions. Observed changes include cell proliferation, the cytoskeleton, signal transduction and gene expression. This review gives an overview of the current knowledge of T cell regulation under altered gravity conditions obtained by in vitro studies with special emphasis on the cell culture conditions used. We propose that future in vitro experiments should follow rigorous standardized cell culture conditions, which allows better comparison of the results obtained in different flight- and ground-based experiment platforms.

Research Possibilities Beyond Deep Space Gateway

NASA Astrophysics Data System (ADS)

Smitherman, D. V.; Needham, D. H.; Lewis, R.

2018-02-01

This abstract explores the possibilities for a large research facilities module attached to the Deep Space Gateway, using the same large module design and basic layout planned for the Deep Space Transport.

A scientific program for infrared, submillimeter and radio astronomy from space: A report by the Management Operations Working Group

NASA Technical Reports Server (NTRS)

1989-01-01

Important and fundamental scientific progress can be attained through space observations in the wavelengths longward of 1 micron. The formation of galaxies, stars, and planets, the origin of quasars and the nature of active galactic nuclei, the large scale structure of the Universe, and the problem of the missing mass, are among the major scientific issues that can be addressed by these observations. Significant advances in many areas of astrophysics can be made over the next 20 years by implementing the outlined program. This program combines large observatories with smaller projects to create an overall scheme that emphasized complementarity and synergy, advanced technology, community support and development, and the training of the next generation of scientists. Key aspects of the program include: the Space Infrared Telescope Facility; the Stratospheric Observatory for Infrared Astronomy; a robust program of small missions; and the creation of the technology base for future major observatories.

Large space telescope, phase A. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1972-01-01

The Phase A study of the Large Space Telescope (LST) is reported. The study defines an LST concept based on the broad mission guidelines provided by the Office of Space Science (OSS), the scientific requirements developed by OSS with the scientific community, and an understanding of long range NASA planning current at the time the study was performed. The LST is an unmanned astronomical observatory facility, consisting of an optical telescope assembly (OTA), scientific instrument package (SIP), and a support systems module (SSM). The report consists of five volumes. The report describes the constraints and trade off analyses that were performed to arrive at a reference design for each system and for the overall LST configuration. A low cost design approach was followed in the Phase A study. This resulted in the use of standard spacecraft hardware, the provision for maintenance at the black box level, growth potential in systems designs, and the sharing of shuttle maintenance flights with other payloads.

LDR structural experiment definition

NASA Technical Reports Server (NTRS)

Russell, Richard A.; Gates, Richard M.

1988-01-01

A study was performed to develop the definition of a structural flight experiment for a large precision segmented reflector that would utilize the Space Station. The objective of the study was to use the Large Deployable Reflector (LDR) baseline configuration for focusing on experiment definition activity which would identify the Space Station accommodation requirements and interface constraints. Results of the study defined three Space Station based experiments to demonstrate the technologies needed for an LDR type structure. The basic experiment configurations are the same as the JPL baseline except that the primary mirror truss is 10 meters in diameter instead of 20. The primary objectives of the first experiment are to construct the primary mirror support truss and to determine its structural and thermal characteristics. Addition of the optical bench, thermal shield and primary mirror segments and alignment of the optical components occur on the second experiment. The structure will then be moved to the payload pointing system for pointing, optical control and scientific optical measurement for the third experiment.