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Sample records for large spacing loop-loop

  1. Observational Evidence for Loop-Loop Interaction

    NASA Astrophysics Data System (ADS)

    Guiping, W.; Guangli, H.; Yuhua, T.; Aoao, X.

    2004-01-01

    Through analysis of the data including the hard x-ray(BASTE) microwave(NoRP) and magnetogram(MDI from SOHO) as well as the images of soft x-ray(YHKOH) and EIT(SOHO) on Apr. 151998 solar flare in the active region 8203(N30W12) we found: (1) there are similar quasi period oscillation in the profile of hard x-ray flux (25-5050-100keV) and microwave flux(1GHz) with duration of 85+/-25s every peak includes two sub-peak structures; (2) in the preheat phase of the flare active magnetic field changes apparently and a s-pole spot emerges ; (3) several EIT and soft x-ray loops exist and turn into bright . All of these may suggest that loop-loop interaction indeed exist. Through reconnection the electrons may be accelerated and the hard x-ray and microwave emission take place.

  2. Large space structures testing

    NASA Technical Reports Server (NTRS)

    Waites, Henry; Worley, H. Eugene

    1987-01-01

    There is considerable interest in the development of testing concepts and facilities that accurately simulate the pathologies believed to exist in future spacecraft. Both the Government and Industry have participated in the development of facilites over the past several years. The progress and problems associated with the development of the Large Space Structure Test Facility at the Marshall Flight Center are presented. This facility was in existence for a number of years and its utilization has run the gamut from total in-house involvement, third party contractor testing, to the mutual participation of other Government Agencies in joint endeavors.

  3. Large size space construction for space exploitation

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey

    2016-07-01

    Space exploitation is impossible without large space structures. We need to make sufficient large volume of pressurized protecting frames for crew, passengers, space processing equipment, & etc. We have to be unlimited in space. Now the size and mass of space constructions are limited by possibility of a launch vehicle. It limits our future in exploitation of space by humans and in development of space industry. Large-size space construction can be made with using of the curing technology of the fibers-filled composites and a reactionable matrix applied directly in free space. For curing the fabric impregnated with a liquid matrix (prepreg) is prepared in terrestrial conditions and shipped in a container to orbit. In due time the prepreg is unfolded by inflating. After polymerization reaction, the durable construction can be fitted out with air, apparatus and life support systems. Our experimental studies of the curing processes in the simulated free space environment showed that the curing of composite in free space is possible. The large-size space construction can be developed. A project of space station, Moon base, Mars base, mining station, interplanet space ship, telecommunication station, space observatory, space factory, antenna dish, radiation shield, solar sail is proposed and overviewed. The study was supported by Humboldt Foundation, ESA (contract 17083/03/NL/SFe), NASA program of the stratospheric balloons and RFBR grants (05-08-18277, 12-08-00970 and 14-08-96011).

  4. 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.

  5. Low Cost Large Space Antennas

    NASA Technical Reports Server (NTRS)

    Chmielewski, Artur B.; Freeland, Robert

    1997-01-01

    The mobile communication community could significantly benefit from the availability of low-cost, large space-deployable antennas. A new class of space structures, called inflatable deployable structures, will become an option for this industry in the near future. This new technology recently made significant progress with respect to reducing the risk of flying large inflatable structures in space. This progress can be attributed to the successful space flight of the Inflatable Antenna Experiment in May of 1996, which prompted the initiation of the NASA portion of the joint NASA/DOD coordinated Space Inflatables Program, which will develop the technology to be used in future mobile communications antennas along with other users. The NASA/DOD coordinated Space Inflatables Program was initiated in 1997 as a direct result of the Inflatable Antenna Experiment. The program adds a new NASA initiative to a substantial DOD program that involves developing a series of ground test hardware, starting with 3 meter diameter units and advancing the manufacturing techniques to fabricate a 25 meter ground demonstrator unit with surface accuracy exceeding the requirements for mobile communication applications. Simultaneously, the program will be advancing the state of the art in several important inflatable technology areas, such as developing rigidizable materials for struts and tori and investigating thin film technology issues, such as application of coatings, property measurement and materials processing and assembly techniques. A very important technology area being addressed by the program is deployment control techniques. The program will sponsor activities that will lead to understanding the effects of material strain energy release, residual air in the stowed structure, and the design of the launch restraint and release system needed to control deployment dynamics. Other technology areas directly applicable to developing inflatable mobile communication antennas in the near

  6. Large space structure damping design

    NASA Technical Reports Server (NTRS)

    Pilkey, W. D.; Haviland, J. K.

    1983-01-01

    Several FORTRAN subroutines and programs were developed which compute complex eigenvalues of a damped system using different approaches, and which rescale mode shapes to unit generalized mass and make rigid bodies orthogonal to each other. An analytical proof of a Minimum Constrained Frequency Criterion (MCFC) for a single damper is presented. A method to minimize the effect of control spill-over for large space structures is proposed. The characteristic equation of an undamped system with a generalized control law is derived using reanalysis theory. This equation can be implemented in computer programs for efficient eigenvalue analysis or control quasi synthesis. Methods to control vibrations in large space structure are reviewed and analyzed. The resulting prototype, using electromagnetic actuator, is described.

  7. Large aperture diffractive space telescope

    DOEpatents

    Hyde, Roderick A.

    2001-01-01

    A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

  8. Uncertainties in large space systems

    NASA Technical Reports Server (NTRS)

    Fuh, Jon-Shen

    1988-01-01

    Uncertainties of a large space system (LSS) can be deterministic or stochastic in nature. The former may result in, for example, an energy spillover problem by which the interaction between unmodeled modes and controls may cause system instability. The stochastic uncertainties are responsible for mode localization and estimation errors, etc. We will address the effects of uncertainties on structural model formulation, use of available test data to verify and modify analytical models before orbiting, and how the system model can be further improved in the on-orbit environment.

  9. 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.

  10. 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.

  11. Large N reduction on coset spaces

    SciTech Connect

    Kawai, Hikaru; Shimasaki, Shinji; Tsuchiya, Asato

    2010-04-15

    As an extension of our previous work concerning the large N reduction on group manifolds, we study the large N reduction on coset spaces. We show that large N field theories on coset spaces are described by certain corresponding matrix models. We also construct Chern-Simons-like theories on group manifolds and coset spaces, and give their reduced models.

  12. Control of large space structures

    NASA Technical Reports Server (NTRS)

    Gran, R.; Rossi, M.; Moyer, H. G.; Austin, F.

    1979-01-01

    The control of large space structures was studied to determine what, if any, limitations are imposed on the size of spacecraft which may be controlled using current control system design technology. Using a typical structure in the 35 to 70 meter size category, a control system design that used actuators that are currently available was designed. The amount of control power required to maintain the vehicle in a stabilized gravity gradient pointing orientation that also damped various structural motions was determined. The moment of inertia and mass properties of this structure were varied to verify that stability and performance were maintained. The study concludes that the structure's size is required to change by at least a factor of two before any stability problems arise. The stability margin that is lost is due to the scaling of the gravity gradient torques (the rigid body control) and as such can easily be corrected by changing the control gains associated with the rigid body control. A secondary conclusion from the study is that the control design that accommodates the structural motions (to damp them) is a little more sensitive than the design that works on attitude control of the rigid body only.

  13. Large Space Antenna Systems Technology, part 1

    NASA Technical Reports Server (NTRS)

    Lightner, E. B. (Compiler)

    1983-01-01

    A compilation of the unclassified papers presented at the NASA Conference on Large Space Antenna Systems Technology covers the following areas: systems, structures technology, control technology, electromagnetics, and space flight test and evaluation.

  14. 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.

  15. Analysis of EM dataset with several sensor configurations obtained by the loop-loop EM survey on magnetic anomalies

    NASA Astrophysics Data System (ADS)

    CHOI, J.; Yi, M. J.; Sasaki, Y.; Son, J.; Nam, M. J.

    2015-12-01

    Most of mineral mines in Korea are located in rugged mountain area embedding small-scale anomalies. Loop-loop EM survey system can be a better choice for exploring those mines because no ground contact is required and portable loops are freely positioned. Survey design is very important for detecting small amount of mineral deposits efficiently and spatial limits of survey lines should be considered. Along a same survey line, surveys with different separations between a transmitter and a receiver are applicable. EM responses are calculated in a layered-earth model embedding magnetic anomalies and analyses considering electric conductivity and magnetic permeability are made for the loop-loop EM survey data. Combining EM dataset with multi-frequency and multi-separation slightly enhanced a reconstructed image. Loop-loop EM survey using PROMOIS system was conducted on a small magnetite mine. Inversion with and without considering magnetic permeability was conducted for EM data with multi-frequency and multi-separation between a transmitter and a receiver.

  16. 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.

  17. 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.

  18. The Large Space Telescope program.

    NASA Technical Reports Server (NTRS)

    O'Dell, C. R.

    1972-01-01

    The 1980's should see the establishment of the first major observatory in space. This observatory will contain a long-lifetime reflecting telescope of about 120 inches clear aperture. Advantages of an orbiting telescope include the elimination of astronomical seeing effects and improvements in resolving power. The small images and darker sky will permit low-dispersion spectrographs to avoid more of the contaminating background. The crispness of the images also has potential for very efficient high-dispersion spectroscopy. A further advantage lies in the accessibility of all the sky and nearly around-the-clock observing.

  19. A case for Large Space Systems Technology

    NASA Technical Reports Server (NTRS)

    Huckins, E. K., III

    1980-01-01

    The NASA Large Space Systems Technology (LSST) program, devoted to the development of Space Shuttle-deployable orbiting structures, is reviewed. The LSST program elements are: antennas, space platforms, assembly equipment and devices, surface sensors and control, control and stabilization, and analysis and design systems. Among the specific prospective applications for this technology base may be counted: multipurpose platforms, materials experimentation facilities, energy satellites, large optical and radio arrays, and communications platforms.

  20. Large space structures - Fantasies and facts

    NASA Technical Reports Server (NTRS)

    Card, M. F.; Boyer, W. J.

    1980-01-01

    A review of large space structures activities from 1973 to 1979 is presented. Long-range studies of space colonies, gigantic solar power stations and projected earth applications revived interest in space activities. Studies suggest opportunities for advanced antenna and platform applications. Matching low-thrust propulsion to large flexible vehicles will be a key technology. Current structures technology investigations include deployable and erectable structures and assembly techniques. Based on orbited structures experience, deployment reliability is a critical issue for deployable structures. For erectable structures, concepts for earth-fabricated and space-fabricated memb

  1. Primary propulsion/large space system interactions

    NASA Technical Reports Server (NTRS)

    Dergance, R. H.

    1980-01-01

    Three generic types of structural concepts and nonstructural surface densities were selected and combined to represent potential LSS applications. The design characteristics of various classes of large space systems that are impacted by primary propulsion thrust required to effect orbit transfer were identified. The effects of propulsion system thrust-to-mass ratio, thrust transients, and performance on the mass, area, and orbit transfer characteristics of large space systems were determined.

  2. Ground test experiment for large space structures

    NASA Technical Reports Server (NTRS)

    Tollison, D. K.; Waites, H. B.

    1985-01-01

    In recent years a new body of control theory has been developed for the design of control systems for Large Space Structures (LSS). The problems of testing this theory on LSS hardware are aggravated by the expense and risk of actual in orbit tests. Ground tests on large space structures can provide a proving ground for candidate control systems, but such tests require a unique facility for their execution. The current development of such a facility at the NASA Marshall Space Flight Center (MSFC) is the subject of this report.

  3. Construction and assembly of large space structures

    NASA Technical Reports Server (NTRS)

    Mar, J. W.; Miller, R. H.; Bowden, M. L.

    1980-01-01

    Three aspects of the construction and assembly of large space structures, namely transportation costs, human productivity in space and the source of materials (lunar vs terrestrial), are considered. Studies on human productivity have been so encouraging that the cost of human labor is now regarded as much less important than transportation costs. It is pointed out that these costs, although high, are extremely demand-sensitive. Even with high demand, however, the construction of several large systems would warrant the use of lunar materials and space manufacturing. The importance of further research is stressed in order to establish the optimum tradeoff between automation and manual assembly.

  4. Advances in Structures for Large Space Systems

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith

    2004-01-01

    The development of structural systems for scientific remote sensing and space exploration has been underway for four decades. The seminal work from 1960 to 1980 provided the basis for many of the design principles of modern space systems. From 1980- 2000 advances in active materials and structures and the maturing of composites technology led to high precision active systems such those used in the Space Interferometry Mission. Recently, thin-film membrane or gossamer structures are being investigated for use in large area space systems because of their low mass and high packaging efficiency. Various classes of Large Space Systems (LSS) are defined in order to describe the goals and system challenges in structures and materials technologies. With an appreciation of both past and current technology developments, future technology challenges are used to develop a list of technology investments that can have significant impacts on LSS development.

  5. Learning to build large structures in space

    NASA Technical Reports Server (NTRS)

    Hagler, T.; Patterson, H. G.; Nathan, C. A.

    1977-01-01

    The paper examines some of the key technologies and forms of construction know-how that will have to be developed and tested for eventual application to building large structures in space. Construction of a shuttle-tended space construction/demonstration platform would comprehensively demonstrate large structure technology, develop construction capability, and furnish a construction platform for a variety of operational large structures. Completion of this platform would lead to demonstrations of the Satellite Power System (SPS) concept, including microwave transmission, fabrication of 20-m-deep beams, conductor installation, rotary joint installation, and solar blanket installation.

  6. 2-D and 3-D joint inversion of loop-loop electromagnetic and electrical data for resistivity and magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Yi, Myeong-Jong; Sasaki, Yutaka

    2015-11-01

    Frequency-domain loop-loop electromagnetic (EM) methods are sensitive to the magnetic susceptibility of the Earth as well as its resistivity. Thus, inversion techniques have been used to simultaneously reconstruct both resistivity and susceptibility models from EM data. However, to take full advantage of inversion methods, calibration errors must be assessed and removed because ignoring them can result in misleading models. We present a multidimensional inversion method that jointly inverts EM and direct current (DC) resistivity data to derive offset errors as well as resistivity and susceptibility models, assuming that calibration errors can be represented by in-phase and quadrature offsets at each frequency. Addition of independent data such as DC data is effective for more accurately estimating the offsets, resulting in more reliable subsurface models. Synthetic examples involving small-loop EM data show that simultaneous inversion for resistivity and susceptibility is not stable, because of strong correlations between in-phase offset parameters and background susceptibility, but that the offsets are well determined when the data misfit is reduced rapidly in the early iteration step. Improvements achieved by joint inversion are mainly on the resistivity model. For airborne electromagnetic (AEM) data, the inversion process is stable, because AEM data are acquired using more loop-loop geometries and a wider range of frequencies. As a result, both the resistivity and susceptibility models are significantly improved by joint inversion.

  7. Analysis incorporating electric conductivity and magnetic permeability on loop-loop EM data for detecting the magnetite ore body

    NASA Astrophysics Data System (ADS)

    Choi, Jihyang; Yi, Myeong-Jong; Son, Jeong-Sul; Kim, Jung-Ho; Park, Sam-Gyu

    2013-04-01

    As the price of mineral resources goes up, exploring small amount of mineral deposits, which have been considered non-economic in the past, is getting more economic. Loop-loop EM survey system can be the best choice for exploring small mineral mines because no ground contact is required and portable loops are freely positioned. EM responses are affected by electric conductivity, magnetic permeability and electric permittivity. In many cases, variation ranges of latter two components are so small and ignorable. However, changes of magnetic permeability affect the data in a serious way. Multidimensional EM inversion technique incorporating both electric conductivity and magnetic susceptibility is on the developing stage. EM responses are calculated in a model of layered earth embedding a magnetic anomaly. Considering the size of the reactions, changes of relative magnetic permeability are frequency-independent effects that can be seen as static. Loop-loop EM survey using PROMIS system was conducted on a small magnetite mine. Inversion with and without considering magnetic permeability was conducted for EM data with multi-frequency and multi-separation between a transmitter and a receiver. Ferromagnetic anomalous feature was distinguishable from the subsurface media, though, enhancement by incorporating magnetic permeability was not sufficiently noticeable.

  8. Environmental effects and large space systems

    NASA Technical Reports Server (NTRS)

    Garrett, H. B.

    1981-01-01

    When planning large scale operations in space, environmental impact must be considered in addition to radiation, spacecraft charging, contamination, high power and size. Pollution of the atmosphere and space is caused by rocket effluents and by photoelectrons generated by sunlight falling on satellite surfaces even light pollution may result (the SPS may reflect so much light as to be a nuisance to astronomers). Large (100 Km 2) structures also will absorb the high energy particles that impinge on them. Altogether, these effects may drastically alter the Earth's magnetosphere. It is not clear if these alterations will in any way affect the Earth's surface climate. Large structures will also generate large plasma wakes and waves which may cause interference with communications to the vehicle. A high energy, microwave beam from the SPS will cause ionospheric turbulence, affecting UHF and VHF communications. Although none of these effects may ultimately prove critical, they must be considered in the design of large structures.

  9. NASA technology for large space antennas

    NASA Technical Reports Server (NTRS)

    Russell, R. A.; Campbell, T. G.; Freeland, R. E.

    1979-01-01

    Technology developed by NASA in conjunction with industry for potential large, deployable space antennas with applications in communication, radio astronomy and earth observation is reviewed. Concepts for deployable antennas that have been developed to the point of detail design are summarized, including the advanced sunflower precision antenna, the radial rib antenna, the maypole (hoop/column) antenna and the parabolic erectable truss antenna. The assessment of state-of-the-art deployable antenna technology is discussed, and the approach taken by the NASA Large Space Systems Technology (LSST) Program to the development of technology for large space antenna systems is outlined. Finally, the further development of the wrap-rib antenna and the maypole (hoop/column) concept, which meet mission model requirements, to satisfy LSST size and frequency requirements is discussed.

  10. Construction and control of large space structures

    NASA Technical Reports Server (NTRS)

    Card, M. F.; Heard, W. L., Jr.; Akin, D. L.

    1986-01-01

    Recent NASA research efforts on space construction are reviewed. Preliminary results of the EASE/ACCESS Shuttle experiments are discussed. A 45-foot beam was constructed on orbit in 30 minutes using a manual assembly technique at a work station. A large tetrahedron was constructed several times using a free floating technique. The capability of repair, utilities installation, and handling the structures using a mobile foot restraint on the RMS was also demonstrated. Implications of the experiments for space station are presented. Models of 5-meter space station structure together with neutral buoyancy simulations suggest manual assembly techniques are feasible. Selected research on control of flexible structures is discussed.

  11. Indian LSSC (Large Space Simulation Chamber) facility

    NASA Technical Reports Server (NTRS)

    Brar, A. S.; Prasadarao, V. S.; Gambhir, R. D.; Chandramouli, M.

    1988-01-01

    The Indian Space Agency has undertaken a major project to acquire in-house capability for thermal and vacuum testing of large satellites. This Large Space Simulation Chamber (LSSC) facility will be located in Bangalore and is to be operational in 1989. The facility is capable of providing 4 meter diameter solar simulation with provision to expand to 4.5 meter diameter at a later date. With such provisions as controlled variations of shroud temperatures and availability of infrared equipment as alternative sources of thermal radiation, this facility will be amongst the finest anywhere. The major design concept and major aspects of the LSSC facility are presented here.

  12. Zone generator for Large Space Telescope technology

    NASA Technical Reports Server (NTRS)

    Erickson, K. E.

    1974-01-01

    A concept is presented for monitoring the optical adjustment and performance of a Large Space Telescope which consists of a 1.2m diameter turntable with a laser stylus to operate at speeds up to 30 rpm. The focus of the laser stylus is under closed loop control. A technique for scribing zones of suitable depth, width, and uniformity applicable to large telescope mirrors is also reported.

  13. Very Large Aperture Diffractive Space Telescope

    SciTech Connect

    Hyde, Roderick Allen

    1998-04-20

    A very large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass ''aiming'' at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The magnifying glass includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the magnifying glass, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets.

  14. Planning for large construction projects in space

    NASA Technical Reports Server (NTRS)

    Disher, J. H.

    1978-01-01

    The paper discusses briefly some broad plans for developing the technology needed for large construction projects in space ranging from orbiting solar power stations to large communications antennas. Space construction classes include assembly of modules, deployment of compacted structures, assembly of passive preformed pieces, and fabrication of structures from sheet stock. Technological areas related to structural concepts include (1) analyses for prediction of structural behavior, structural/control interaction, electromagnetic and control performance, and integrated design development; (2) electronics for signal conditioning and data acquisition, power distribution, and signal channel interference and multipaction; (3) concepts for shape control, attitude/pointing control, and orbital transfer and station keeping; and (4) materials and techniques for 30-year dimensional stable composites, thermal control, thin-lightweight structural alloys, and material joining in space. The concept of a power module for the construction operations is discussed along with a concept for a habitability module.

  15. Large area space solar cell assemblies

    NASA Technical Reports Server (NTRS)

    Spitzer, M. B.; Nowlan, M. J.

    1982-01-01

    Development of a large area space solar cell assembly is presented. The assembly consists of an ion implanted silicon cell and glass cover. The important attributes of fabrication are (1) use of a back surface field which is compatible with a back surface reflector, and (2) integration of coverglass application and call fabrication.

  16. Microwave performance characterization of large space antennas

    NASA Technical Reports Server (NTRS)

    Bathker, D. A. (Editor)

    1977-01-01

    Performance capabilities of large microwave space antenna configurations with apertures generally from 100 wavelengths upwards are discussed. Types of antennas considered include: phased arrays, lenses, reflectors, and hybrid combinations of phased arrays with reflectors or lenses. The performance characteristics of these broad classes of antennas are examined and compared in terms of applications.

  17. EVA assembly of large space structure element

    NASA Technical Reports Server (NTRS)

    Bement, L. J.; Bush, H. G.; Heard, W. L., Jr.; Stokes, J. W., Jr.

    1981-01-01

    The results of a test program to assess the potential of manned extravehicular activity (EVA) assembly of erectable space trusses are described. Seventeen tests were conducted in which six "space-weight" columns were assembled into a regular tetrahedral cell by a team of two "space"-suited test subjects. This cell represents the fundamental "element" of a tetrahedral truss structure. The tests were conducted under simulated zero-gravity conditions. Both manual and simulated remote manipulator system modes were evaluated. Articulation limits of the pressure suit and zero gravity could be accommodated by work stations with foot restraints. The results of this study have confirmed that astronaut EVA assembly of large, erectable space structures is well within man's capabilities.

  18. Construction and control of large space structures

    NASA Technical Reports Server (NTRS)

    Card, M. F.; Heard, W. L., Jr.; Akin, D. L.

    1986-01-01

    Recent NASA research efforts on space construction are reviewed. Preliminary results of the EASE/ACCESS Shuttle experiments are discussed. A 45-foot beam was constructed on orbit in 30 minutes using a manual assembly technique at a work station. A large tetrahedron was constructed several times using a free floating technique. The capability of repair, utilities installation, and handling the structures using a mobile foot restraint on the RMS was also demonstrated. Implications of the experiments for Space Station are presented. Models of 5-meter Space Station structure together with neutral buoyancy simulations suggest manual assembly techniques are feasible. Selected research on control of flexible structures is discussed. To support planned flight experiments, studies of the design and optimal placement of distributed active dampers are underway.

  19. Data management for Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Hope, G. R., Jr.; Rasser, T. J.

    1975-01-01

    The data management system for the Large Space Telescope (LST) must be capable of meeting requirements of 160 million bits per 95 min orbit with a bit error rate of less than 0.00001 for data. The system will be supported by the Tracking and Data Relay Satellite System of the Space Tracking and Data Network. The on-board system includes a general purpose computer that controls the vehicle as a stable observation platform and the array of instruments used for data collection. The ground-based system comprises a Mission Operations Center (MOC), a Science Institute where instrument data is processed, and a communications service for the space and point-to-point data flow. The allocation of hardware and software between on-board and ground-based components to achieve design objectives of maximum flexibility at minimum cost is discussed.

  20. Large space structures control algorithm characterization

    NASA Technical Reports Server (NTRS)

    Fogel, E.

    1983-01-01

    Feedback control algorithms are developed for sensor/actuator pairs on large space systems. These algorithms have been sized in terms of (1) floating point operation (FLOP) demands; (2) storage for variables; and (3) input/output data flow. FLOP sizing (per control cycle) was done as a function of the number of control states and the number of sensor/actuator pairs. Storage for variables and I/O sizing was done for specific structure examples.

  1. Accuracy potentials for large space antenna structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1980-01-01

    The relationships among materials selection, truss design, and manufacturing techniques in the interest of surface accuracies for large space antennas are discussed. Among the antenna configurations considered are: tetrahedral truss, pretensioned truss, and geodesic dome and radial rib structures. Comparisons are made of the accuracy achievable by truss and dome structure types for a wide variety of diameters, focal lengths, and wavelength of radiated signal, taking into account such deforming influences as solar heating-caused thermal transients and thermal gradients.

  2. Some design considerations for large space structures

    NASA Technical Reports Server (NTRS)

    Bush, H. G.; Mikulas, M. M., Jr.; Heard, W. L., Jr.

    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.

  3. Survey of future requirements for large space structures. [space platforms, large antennas, and power surfaces

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1976-01-01

    The future requirements for large space structures were examined and the foundation for long range planning of technology development for such structures is provided. Attention is concentrated on a period after 1985 for actual use. Basic ground rule of the study was that applications be of significant importance and have promise of direct economic benefit to mankind. The inputs to the study came from visits to a large number of government and industrial organizations, written studies in current literature, and approximate analyses of potential applications. The paper identifies diverse space applications for large area structures in three general categories: (1) large surfaces for power, (2) large antenna to receive and transmit energy over the radio frequency bandwidth, and (3) space platforms to provide area for general utilizations.

  4. Adaptive momentum management for large space structures

    NASA Technical Reports Server (NTRS)

    Hahn, E.

    1987-01-01

    Momentum management is discussed for a Large Space Structure (LSS) with the structure selected configuration being the Initial Orbital Configuration (IOC) of the dual keel space station. The external forces considered were gravity gradient and aerodynamic torques. The goal of the momentum management scheme developed is to remove the bias components of the external torques and center the cyclic components of the stored angular momentum. The scheme investigated is adaptive to uncertainties of the inertia tensor and requires only approximate knowledge of principle moments of inertia. Computational requirements are minimal and should present no implementation problem in a flight type computer and the method proposed is shown to be effective in the presence of attitude control bandwidths as low as .01 radian/sec.

  5. Passive stabilization for large space systems

    NASA Technical Reports Server (NTRS)

    Sesak, J. R.; Gronet, M. J.; Marinos, G. M.

    1987-01-01

    The optimal tuning of multiple tuned-mass dampers for the transient vibration damping of large space structures is investigated. A multidisciplinary approach is used. Structural dynamic techniques are applied to gain physical insight into absorber/structure interaction and to optimize specific cases. Modern control theory and parameter optimization techniques are applied to the general optimization problem. A design procedure for multi-absorber multi-DOF vibration damping problems is presented. Classical dynamic models are extended to investigate the effects of absorber placement, existing structural damping, and absorber cross-coupling on the optimal design synthesis. The control design process for the general optimization problem is formulated as a linear output feedback control problem via the development of a feedback control canonical form. The techniques are applied to sample micro-g and pointing problems on the NASA dual keel space station.

  6. In-space construction and dynamics of large space structures

    NASA Technical Reports Server (NTRS)

    Mikulas, Martin M., Jr.

    1990-01-01

    The types of equipment and structures that will be required to construct very large spacecraft in space are discussed. One of the basic issues that must be resolved is the appropriate mix of humans and machines in the construction process. While the use of robots offers the potential for reducing the number of extra-vehicular activity (EVA) hours required for particular construction operations, the availability of humans greatly increases the reliability of complex construction tasks. A hybrid system is described which makes the best use of man and machine to provide a highly reliable and versatile construction approach. Such a system will provide an efficient method for constructing large spacecraft until fully automated, robotic devices can be perfected. Details are given on an extensive ground test program which was designed to evaluate and demonstrate large spacecraft construction. A discussion is presented on the use of the Space Station Freedom, or an appropriate derivative, as a construction facility. Finally, a construction scenario and assembly timelines are presented for constructing a 20-meter-diameter high precision reflector.

  7. Cooling Technology for Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    DiPirro, Michael; Cleveland, Paul; Durand, Dale; Klavins, Andy; Muheim, Daniella; Paine, Christopher; Petach, Mike; Tenerelli, Domenick; Tolomeo, Jason; Walyus, Keith

    2007-01-01

    NASA's New Millennium Program funded an effort to develop a system cooling technology, which is applicable to all future infrared, sub-millimeter and millimeter cryogenic space telescopes. In particular, this technology is necessary for the proposed large space telescope Single Aperture Far-Infrared Telescope (SAFIR) mission. This technology will also enhance the performance and lower the risk and cost for other cryogenic missions. The new paradigm for cooling to low temperatures will involve passive cooling using lightweight deployable membranes that serve both as sunshields and V-groove radiators, in combination with active cooling using mechanical coolers operating down to 4 K. The Cooling Technology for Large Space Telescopes (LST) mission planned to develop and demonstrate a multi-layered sunshield, which is actively cooled by a multi-stage mechanical cryocooler, and further the models and analyses critical to scaling to future missions. The outer four layers of the sunshield cool passively by radiation, while the innermost layer is actively cooled to enable the sunshield to decrease the incident solar irradiance by a factor of more than one million. The cryocooler cools the inner layer of the sunshield to 20 K, and provides cooling to 6 K at a telescope mounting plate. The technology readiness level (TRL) of 7 will be achieved by the active cooling technology following the technology validation flight in Low Earth Orbit. In accordance with the New Millennium charter, tests and modeling are tightly integrated to advance the technology and the flight design for "ST-class" missions. Commercial off-the-shelf engineering analysis products are used to develop validated modeling capabilities to allow the techniques and results from LST to apply to a wide variety of future missions. The LST mission plans to "rewrite the book" on cryo-thermal testing and modeling techniques, and validate modeling techniques to scale to future space telescopes such as SAFIR.

  8. Robust Control Design for Large Space Structures

    NASA Technical Reports Server (NTRS)

    Eastman, W. L.; Bossi, J. A.

    1985-01-01

    The control design problem for the class of future spacecraft referred to as large space structures (LSS) is by now well known. The issue is the reduced order control of a very high order, lightly damped system with uncertain system parameters, particularly in the high frequency modes. A design methodology which incorporates robustness considerations as part of the design process is presented. Combining pertinent results from multivariable systems theory and optimal control and estimation, LQG eigenstructure assignment and LQG frequency shaping, were used to improve singular value robustness measures in the presence of control and observation spillover.

  9. Distributed control of large space antennas

    NASA Technical Reports Server (NTRS)

    Cameron, J. M.; Hamidi, M.; Lin, Y. H.; Wang, S. J.

    1983-01-01

    A systematic way to choose control design parameters and to evaluate performance for large space antennas is presented. The structural dynamics and control properties for a Hoop and Column Antenna and a Wrap-Rib Antenna are characterized. Some results of the effects of model parameter uncertainties to the stability, surface accuracy, and pointing errors are presented. Critical dynamics and control problems for these antenna configurations are identified and potential solutions are discussed. It was concluded that structural uncertainties and model error can cause serious performance deterioration and can even destabilize the controllers. For the hoop and column antenna, large hoop and long meat and the lack of stiffness between the two substructures result in low structural frequencies. Performance can be improved if this design can be strengthened. The two-site control system is more robust than either single-site control systems for the hoop and column antenna.

  10. Large space antenna concepts for ESGP

    NASA Technical Reports Server (NTRS)

    Love, Allan W.

    1989-01-01

    It is appropriate to note that 1988 marks the 100th anniversary of the birth of the reflector antenna. It was in 1888 that Heinrich Hertz constructed the first one, a parabolic cylinder made of sheet zinc bent to shape and supported by a wooden frame. Hertz demonstrated the existence of the electromagnetic waves that had been predicted theoretically by James Clerk Maxwell some 22 years earlier. In the 100 years since Hertz's pioneering work the field of electromagnetics has grown explosively: one of the technologies is that of remote sensing of planet Earth by means of electromagnetic waves, using both passive and active sensors located on an Earth Science Geostationary Platform (ESEP). For these purposes some exquisitely sensitive instruments were developed, capable of reaching to the fringes of the known universe, and relying on large reflector antennas to collect the minute signals and direct them to appropriate receiving devices. These antennas are electrically large, with diameters of 3000 to 10,000 wavelengths and with gains approaching 80 to 90 dB. Some of the reflector antennas proposed for ESGP are also electrically large. For example, at 220 GHz a 4-meter reflector is nearly 3000 wavelengths in diameter, and is electrically quite comparable with a number of the millimeter wave radiotelescopes that are being built around the world. Its surface must meet stringent requirements on rms smoothness, and ability to resist deformation. Here, however, the environmental forces at work are different. There are no varying forces due to wind and gravity, but inertial forces due to mechanical scanning must be reckoned with. With this form of beam scanning, minimizing momentum transfer to the space platform is a problem that demands an answer. Finally, reflector surface distortion due to thermal gradients caused by the solar flux probably represents the most challenging problem to be solved if these Large Space Antennas are to achieve the gain and resolution required of

  11. Large space antenna concepts for ESGP

    NASA Astrophysics Data System (ADS)

    Love, Allan W.

    1989-07-01

    It is appropriate to note that 1988 marks the 100th anniversary of the birth of the reflector antenna. It was in 1888 that Heinrich Hertz constructed the first one, a parabolic cylinder made of sheet zinc bent to shape and supported by a wooden frame. Hertz demonstrated the existence of the electromagnetic waves that had been predicted theoretically by James Clerk Maxwell some 22 years earlier. In the 100 years since Hertz's pioneering work the field of electromagnetics has grown explosively: one of the technologies is that of remote sensing of planet Earth by means of electromagnetic waves, using both passive and active sensors located on an Earth Science Geostationary Platform (ESEP). For these purposes some exquisitely sensitive instruments were developed, capable of reaching to the fringes of the known universe, and relying on large reflector antennas to collect the minute signals and direct them to appropriate receiving devices. These antennas are electrically large, with diameters of 3000 to 10,000 wavelengths and with gains approaching 80 to 90 dB. Some of the reflector antennas proposed for ESGP are also electrically large. For example, at 220 GHz a 4-meter reflector is nearly 3000 wavelengths in diameter, and is electrically quite comparable with a number of the millimeter wave radiotelescopes that are being built around the world. Its surface must meet stringent requirements on rms smoothness, and ability to resist deformation. Here, however, the environmental forces at work are different. There are no varying forces due to wind and gravity, but inertial forces due to mechanical scanning must be reckoned with. With this form of beam scanning, minimizing momentum transfer to the space platform is a problem that demands an answer. Finally, reflector surface distortion due to thermal gradients caused by the solar flux probably represents the most challenging problem to be solved if these Large Space Antennas are to achieve the gain and resolution required of

  12. Large space systems auxiliary propulsion requirements

    NASA Astrophysics Data System (ADS)

    Maloy, J. E.; Smith, W. W.

    1983-05-01

    To meet the needs of a variety of civilian and military missions objectives large space systems (LSS) will become a greater percentage of our orbiting hardware. These LSS's will be transported to low Earth orbit (LEO) by the space transportation system (STS Shuttle). Concurrently, for LSS missions to orbit higher than LEO, the predominant mission scenario is that the LSS will be deployed or assembled in LEO and then transferred to a higher orbit. In support of the LSS concepts, the Office of Aeronautics and Space Technology (OAST) has sponsored studies to determine LSS mission propulsion requirements. Since the fall of 1979, the Boeing Aerospace Company, under contract to NASA and Lewis Research Center, has been studying the disturbance forces and torques that will be experienced by LSS, and they have identified some of the associated auxiliary propulsion systems (APS) requirements. This presentation provides an insight into the results of some of the APS studies, focusing primarily on the APS requirements of single Shuttle launchable LSS's.

  13. Structural sizing considerations for large space structures

    NASA Technical Reports Server (NTRS)

    Heard, W. L., Jr.; Bush, H. G.; Walz, J. E.

    1981-01-01

    A number of missions for the space shuttle were proposed which involve placing large truss platforms on-orbit. These platforms range in size from tens of meters in span for reflector application to several thousand meters for solar power collector application. These proposed sizes and the operational requirements considered are unconventional in comparison to Earthbound structures and little information exists concerning efficient proportions of the structural elements forming the framework of the platforms. Such proportions are of major concern because they have a strong influence on the packaging efficiency and, thus, the transportation effectiveness of the shuttle. The present study is undertaken to: (1) identify efficient ranges of application of deployable and erectable platforms configured for shuttle transport to orbit, and (2) determine sensitivity to key parameters of minimum mass deployable and erectable platform designs.

  14. Large active retrodirective arrays for space applications

    NASA Technical Reports Server (NTRS)

    Chernoff, R. C.

    1979-01-01

    An active retrodirective array (ARA) transmits a beam toward the apparent source of an illuminating signal called the pilot. The term active implies that the array produces, not merely reflects, RF power. Retrodirectivity is achieved by retransmitting from each element of the array a signal whose phase is the conjugate of that received by the element. The problem of supplying the correct phase reference to the phase conjugation circuit (PCC) is solved by central phasing. A new form of central phasing suitable for very large arrays is outlined. ARAs may serve simultaneously as transmitting and receiving satellite antennas for space applications. Precision pointing and input-output isolation is provided by exact frequency-translating PCCs. A two-element ARA breadboard has been built and tested.

  15. Travelling wave effects in large space structures

    NASA Technical Reports Server (NTRS)

    Vonflotow, A.

    1983-01-01

    Several aspects of travelling waves in Large Space Structures(LSS) are discussed. The dynamic similarity among LSS's, electric power systems, microwave circuits and communications network is noted. The existence of time lag between actuation and response is illuminated with the aid of simple examples, and their prediction is demonstrated. To prevent echoes, communications lines have matched terminations; this idea is applied to the design of dampers of one dimensional structures. Periodic structures act as mechanical band pass filters. Implications of this behavior are examined on a simple example. It is noted that the implication is twofold; continuum models of periodic lattice structures may err considerably; on the other hand, it is possible to design favorable transmission (and resonance) characteristics into the structure.

  16. Space transportation alternatives for large space programs: The International Space University Summer Session, 1992

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    1993-01-01

    In 1992, the International Space University (ISU) held its Summer Session in Kitakyushu, Japan. This paper summarizes and expands upon some aspects of space solar power and space transportation that were considered during that session. The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW, or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. A high-cost space transportation program is potentially the most crippling barrier to such a space power program. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed. Over 120 students from 29 countries participated in this summer session. The results discussed in this paper, therefore, represent the efforts of many nations.

  17. Offloading techniques for large deployable space structures

    NASA Technical Reports Server (NTRS)

    Caravaggio, Levino; Golob, Alex

    1992-01-01

    The validation and verification of large deployable space structures are continual challenges which face the integration and test engineer today. Spar Aerospace Limited has worked on various programs in which such structure validation was required and faces similar tasks in the future. This testing is reported and the different offloading and deployment methods which were used, as well as the proposed methods which will be used on future programs, are described. Past programs discussed include the Olympus solar array ambient and thermal vacuum deployments, and the Anik-E array and reflector deployments. The proposed MSAT reflector and boom ambient deployment tests, as well as the proposed RADARSAT Synthetic Aperture Radar (SAR) ambient and thermal vacuum deployment tests will also be presented. A series of tests relating to various component parts of the offloading equipment systems was required. These tests included the characterization and understanding of linear bearings and large (180 in-lbf) constant force spring motors in a thermal vacuum environment, and the results from these tests are presented.

  18. International space station. Large scale integration approach

    NASA Astrophysics Data System (ADS)

    Cohen, Brad

    The International Space Station is the most complex large scale integration program in development today. The approach developed for specification, subsystem development, and verification lay a firm basis on which future programs of this nature can be based. International Space Station is composed of many critical items, hardware and software, built by numerous International Partners, NASA Institutions, and U.S. Contractors and is launched over a period of five years. Each launch creates a unique configuration that must be safe, survivable, operable, and support ongoing assembly (assemblable) to arrive at the assembly complete configuration in 2003. The approaches to integrating each of the modules into a viable spacecraft and continue the assembly is a challenge in itself. Added to this challenge are the severe schedule constraints and lack of an "Iron Bird", which prevents assembly and checkout of each on-orbit configuration prior to launch. This paper will focus on the following areas: 1) Specification development process explaining how the requirements and specifications were derived using a modular concept driven by launch vehicle capability. Each module is composed of components of subsystems versus completed subsystems. 2) Approach to stage (each stage consists of the launched module added to the current on-orbit spacecraft) specifications. Specifically, how each launched module and stage ensures support of the current and future elements of the assembly. 3) Verification approach, due to the schedule constraints, is primarily analysis supported by testing. Specifically, how are the interfaces ensured to mate and function on-orbit when they cannot be mated before launch. 4) Lessons learned. Where can we improve this complex system design and integration task?

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Space transportation alternatives for large space programs - The International Space University summer session - 1992

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    1993-01-01

    The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group at the International Space University (ISU) summer session of 1992 to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed.

  4. A technology program for large area space systems

    NASA Technical Reports Server (NTRS)

    Guastaferro, A.; Jenkins, L. M.

    1978-01-01

    The large space systems technology program (LSST) is discussed. The purpose of LSST is to define and develop technology for large space systems and associated subsystems required for projected NASA space missions. Goals involving structural concepts and supporting technology are surveyed. The application of LSST to the design of the solar power satellite is considered.

  5. Large space systems in global change mitigation

    NASA Technical Reports Server (NTRS)

    Jenkins, Lyle M.

    1990-01-01

    The monitoring from space of such processes as the greenhouse effect and depletion of the ozone layer is discussed, as well as possibilities for active intervention in them, using space systems. Possibilities include the use of the Solar Power Satellite to reduce dependence on the burning of fossil fuels, dispersal of materials to neutralize chemicals responsible for ozone depletion, and measures to reduce the impact of local disasters, both natural and man-made.

  6. Technical issues in dynamics and control of large space structures

    NASA Technical Reports Server (NTRS)

    Card, M. F.; Anderson, W. W.

    1983-01-01

    Examples of large space systems currently being considered by NASA include a large communications antenna system (the Land Mobile Satellite System), a precision antenna system (the Large Deployable Reflector System), and a preliminary concept for NASA's space station. Each system has low natural vibration frequencies, stringent pointing requirements, and, for the antennas, demanding surface accuracy requirements. A review is provided of the progress being made in structural ground tests with respect to surface accuracy, deployment, and erection of large structures. Attention is given to the dynamic loads on large space structures, on-orbit testing, space vibration control devices, and the characteristics of distributed control.

  7. The 1980 Large space systems technology. Volume 2: Base technology

    NASA Technical Reports Server (NTRS)

    Kopriver, F., III (Compiler)

    1981-01-01

    Technology pertinent to large antenna systems, technology related to large space platform systems, and base technology applicable to both antenna and platform systems are discussed. Design studies, structural testing results, and theoretical applications are presented with accompanying validation data. A total systems approach including controls, platforms, and antennas is presented as a cohesive, programmatic plan for large space systems.

  8. Modeling, Analysis, and Optimization Issues for Large Space Structures

    NASA Technical Reports Server (NTRS)

    Pinson, L. D. (Compiler); Amos, A. K. (Compiler); Venkayya, V. B. (Compiler)

    1983-01-01

    Topics concerning the modeling, analysis, and optimization of large space structures are discussed including structure-control interaction, structural and structural dynamics modeling, thermal analysis, testing, and design.

  9. 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.

  10. Gamma-Ray Large Area Space Telescope- GLAST Mission Overview

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander A.

    2007-01-01

    This viewgraph presentation reviews the Gamma-ray Large Area Space Telescope (GLAST), and the instrumentation that will be on the spacecraft: Large Area Telescope (LAT) and GLAST Burst Monitor (GBM). The presentation revierws in detail the LAT instrument.

  11. 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.

  12. Learning Theory for Collaborative Large Shared Digital Spaces

    ERIC Educational Resources Information Center

    McGivern, Daniela; Morgan, Michael; Butler, Matthew

    2012-01-01

    This research applies Socio-Cultural theory and Distributed Cognition/Activity theory to conceptualize the design of collaborative learning activities in large shared digital spaces. The paper begins by providing a summary of previous work in the creation of a technology platform for large shared digital spaces. It then details how Socio-Cultural…

  13. A technology program for large area space systems

    NASA Technical Reports Server (NTRS)

    Guastaferro, A.

    1979-01-01

    The broad objective of the Large Space Systems Technology (LSST) program is to define and develop the necessary technology for large space systems and associated subsystems required for projected NASA space missions. It is a goal of LSST to make these systems economically and technically feasible by focusing on those technical activities believed to provide the greatest benefit to a variety of future systems. Emphasis is placed on two principal structural configurations: antennas and platforms.

  14. Large Active Retrodirective Arrays for Space Applications

    NASA Technical Reports Server (NTRS)

    Chernoff, R. C.

    1978-01-01

    An active retrodirective array (ARA) electronically points a microwave beam back at the apparent source of an incident pilot signal. Retrodirectivity is the result of phase conjugation of the pilot signal received by each element of the array. The problem of supplying the correct phase reference to the phase conjugation circuit (PCC) associated with each element of the array is solved by central phasing. By eliminating the need for structural rigidity, central phasing confers a decisive advantage on ARA's as large spaceborne antennas. A new form of central phasing suitable for very large arrays is described. ARA's may easily be modified to serve both as transmitting and receiving arrays simultaneously. Two new kinds of exact, frequency translating PCC's are described. Such PCC's provide the ARA with input-output isolation and freedom from squint. The pointing errors caused by the radial and transverse components of the ARA's velocity, by the propagation medium, and by multipath are discussed. A two element ARA breadboard was built and tested at JPL. Its performance is limited primarily by multipath induced errors.

  15. Astronomers, Congress, and the Large Space Telescope

    NASA Astrophysics Data System (ADS)

    Hanle, P. A.

    1985-04-01

    The Hubble Space Telescope (HST) project was initiated near the end of the Apollo program and immediately encountered fiscal contraints. Planned as a long-term facility, the HST had to be continually justified to the public, astronomers and Congress from 1973 onward. Budgetary restraints caused design reductions which for a while threatened the practicality of the HST and changed it from a pressurized, manned unit to an automatic mode, teleoperated, intermittently visited spacecraft. It is noted that numerous exaggerations were made of both the power of the HST for scientific research and the total support of the astronomical community during promotion of the HST program, although the HST is the most powerful visual wavelength telescope ever to be built due to its unique operating environment. NASA's consistent and steadily more detailed definitions of the design features and missions of the HST proved to be a decisive factor in repeated requests for information by funding committees who were deliberating in the presence of severe fiscal difficulties.

  16. The Space Station as a Construction Base for Large Space Structures

    NASA Technical Reports Server (NTRS)

    Gates, R. M.

    1985-01-01

    The feasibility of using the Space Station as a construction site for large space structures is examined. An overview is presented of the results of a program entitled Definition of Technology Development Missions (TDM's) for Early Space Stations - Large Space Structures. The definition of LSS technology development missions must be responsive to the needs of future space missions which require large space structures. Long range plans for space were assembled by reviewing Space System Technology Models (SSTM) and other published sources. Those missions which will use large space structures were reviewed to determine the objectives which must be demonstrated by technology development missions. The three TDM's defined during this study are: (1) a construction storage/hangar facility; (2) a passive microwave radiometer; and (3) a precision optical system.

  17. Weight control of a large space booster

    NASA Astrophysics Data System (ADS)

    Metheny, Gary R.

    1989-05-01

    The Titan IV vehicle, a stretching of the Titan III to possess longer fuel and oxidizer tanks on both stages while retaining the constant, 10-ft diameter, would have to withstand larger P-equivalent loads due to the increased weight of skin, stringer, and frame structure strengthening. Upon analysis, it was established that increased vehicle and payload fairing lengths imparted a large bending moment to the booster at design Q-alpha total flight conditions, so that stiffness rather than axial load became the design driver. Weight problems thus incurred were addressed by critical structural element analyses using target weight vs stress margin comparisons. Items were thus identified for successful weight reduction treatment.

  18. NASA/Howard University Large Space Structures Institute

    NASA Technical Reports Server (NTRS)

    Broome, T. H., Jr.

    1984-01-01

    Basic research on the engineering behavior of large space structures is presented. Methods of structural analysis, control, and optimization of large flexible systems are examined. Topics of investigation include the Load Correction Method (LCM) modeling technique, stabilization of flexible bodies by feedback control, mathematical refinement of analysis equations, optimization of the design of structural components, deployment dynamics, and the use of microprocessors in attitude and shape control of large space structures. Information on key personnel, budgeting, support plans and conferences is included.

  19. Developing closed life support systems for large space habitats

    NASA Technical Reports Server (NTRS)

    Phillips, J. M.; Harlan, A. D.; Krumhar, K. C.

    1978-01-01

    In anticipation of possible large-scale, long-duration space missions which may be conducted in the future, NASA has begun to investigate the research and technology development requirements to create life support systems for large space habitats. An analysis suggests the feasibility of a regeneration of food in missions which exceed four years duration. Regeneration of food in space may be justified for missions of shorter duration when large crews must be supported at remote sites such as lunar bases and space manufacturing facilities. It is thought that biological components consisting principally of traditional crop and livestock species will prove to be the most acceptable means of closing the food cycle. A description is presented of the preliminary results of a study of potential biological components for large space habitats. Attention is given to controlled ecosystems, Russian life support system research, controlled-environment agriculture, and the social aspects of the life-support system.

  20. Risk to space sustainability from large constellations of satellites

    NASA Astrophysics Data System (ADS)

    Bastida Virgili, B.; Dolado, J. C.; Lewis, H. G.; Radtke, J.; Krag, H.; Revelin, B.; Cazaux, C.; Colombo, C.; Crowther, R.; Metz, M.

    2016-09-01

    The number of artificial objects in orbit continues to increase and, with it, a key threat to space sustainability. In response, space agencies have identified a set of mitigation guidelines aimed at enabling space users to reduce the generation of space debris by, for example, limiting the orbital lifetime of their spacecraft and launcher stages after the end of their mission. Planned, large constellations of satellites in low Earth orbit (LEO), though addressing the lack of basic internet coverage in some world regions, may disrupt the sustainability of the space environment enabled by these mitigation practices. We analyse the response of the space object population to the introduction of a large constellation conforming to the post-mission disposal guideline with differing levels of success and with different disposal orbit options. The results show that a high success rate of post-mission disposal by constellation satellites is a key driver for space sustainability.

  1. The Deep Space Network Large Array

    NASA Astrophysics Data System (ADS)

    Gatti, M. S.

    2004-05-01

    In recent years it has become evident that, if future science needs are to be met, the capacity of the telecommunications link between planetary spacecraft and the Earth must be increased by orders of magnitude. Both the number of spacecraft and higher data rates demand the increased capacity. Technologies to support the increased capacity include even larger antennas, optical receiving systems, or arrays of antennas. This article describes a large array of small antennas that would be implemented for a fraction of the cost of an equivalent 70-m aperture. Adding additional antennas can increase the sensitivity many fold over current capabilities. The array will consist of 400 parabolic reflector antennas, each of which will be 12 m in diameter. Each antenna will operate simultaneously at both X-band (8 to 8.8 GHz) and Ka-band (31 to 38 GHz) and will be configured with radio frequency (RF) electronics, including the feeds, low-noise amplifiers, and frequency converters, as well as the appropriate servo controls and drives. The array also includes the signal transmission and signal processing to enable the system to track from between 1 and 16 different signals. A significant feature of this system is that it will be done for relatively very low cost compared to the current antenna paradigms. This is made possible by the use of low-cost antenna reflector technology, the extensive use of monolithic microwave integrated circuits (MMICs), and, finally, by using commercially available equipment to the maximum extent possible. Cost can be further reduced by the acceptance of lower antenna element reliability. High system availability will be maintained by a design paradigm that provides for a marginal set of excess antenna elements for any particular tracking period. Thus, the same total system availability is achieved for lower element availability. The "plug-and-play" aspects of the assemblies will enhance maintainability and operability. The project plans include a

  2. Artwork By: Don Davis Space Colony: Torus Wheel - Large assemblies can be put togetherin space. Here

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Artwork By: Don Davis Space Colony: Torus Wheel - Large assemblies can be put togetherin space. Here panels of a colony are being fitted in place. The small vehicles are called ANTS for Assembly non-thethered ships

  3. 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.

  4. Large size greenhouse for long-term space missions

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey

    Crew space flights require on-going delivery of food, air and water from Earth. A long time missions in far space cannot be realized without self-supported life system, when food, air and water will be reused. For ecological self-regulated life support system a large volume of green house is needed. An inflatable construction of composite materials cured directly in free space environment is a way for development of large greenhouse. The rigidization of the frame by the way of chemical reaction of polymerization is viewed as real way. The large volume greenhouse created on Earth orbit is proposed. The construction and material of space greenhouse are considered based on results of biological investigations in space flights.

  5. Distributed active control of large flexible space structures

    NASA Technical Reports Server (NTRS)

    Nguyen, C. C.; Baz, A.

    1986-01-01

    This progress report summarizes the research work performed at the Catholic University of America on the research grant entitled Distributed Active Control of Large Flexible Space Structures, funded by NASA/Goddard Space Flight Center, under grant number NAG5-749, during the period of March 15, 1986 to September 15, 1986.

  6. Nonterrestrial material processing and manufacturing of large space systems

    NASA Technical Reports Server (NTRS)

    Vontiesenhausen, G. F.

    1978-01-01

    An attempt is made to provide pertinent and readily usable information on the extraterrestrial processing of materials and manufacturing of components and elements of these planned large space systems from preprocessed lunar materials which are made available at a processing and manufacturing site in space. Required facilities, equipment, machinery, energy and manpower are defined.

  7. An improved output feedback control of flexible large space structures

    NASA Technical Reports Server (NTRS)

    Lin, Y. H.; Lin, J. G.

    1980-01-01

    A special output feedback control design technique for flexible large space structures is proposed. It is shown that the technique will increase both the damping and frequency of selected modes for more effective control. It is also able to effect integrated control of elastic and rigid-body modes and, in particular, closed-loop system stability and robustness to modal truncation and parameter variation. The technique is seen as marking an improvement over previous work concerning large space structures output feedback control.

  8. NASA/MSFC Large Space Structures Ground Test Facility

    NASA Technical Reports Server (NTRS)

    Jones, Victoria L.; Bukley, Angelia P.; Patterson, Alan F.

    1991-01-01

    This paper describes the NASA/MSFC Large Space Structures Ground Test Facility (LSS GTF) which has been developed for the purpose of implementing, testing, and evaluating LSS control and system identification techniques on representative large space structures. The facility presently consists of two laboratories: the Single Structure Control (SSC) Laboratory, which has been operational since 1984, and the Controls and Structures Experiment in Space (CASES) GTF which is presently under development. Test results from several experiments in the SSC laboratory are presented. The results of component testing and boom modal tests are presented for the CASES facility.

  9. Benchmarking processes for managing large international space programs

    NASA Technical Reports Server (NTRS)

    Mandell, Humboldt C., Jr.; Duke, Michael B.

    1993-01-01

    The relationship between management style and program costs is analyzed to determine the feasibility of financing large international space missions. The incorporation of management systems is considered to be essential to realizing low cost spacecraft and planetary surface systems. Several companies ranging from large Lockheed 'Skunk Works' to small companies including Space Industries, Inc., Rocket Research Corp., and Orbital Sciences Corp. were studied. It is concluded that to lower the prices, the ways in which spacecraft and hardware are developed must be changed. Benchmarking of successful low cost space programs has revealed a number of prescriptive rules for low cost managements, including major changes in the relationships between the public and private sectors.

  10. Potential Large Decadal Missions Enabled by Nasas Space Launch System

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David Alan; Jackman, Angela; Warfield, Keith R.

    2016-01-01

    Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope (HST) was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope (JWST) is specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultra-high-contrast spectroscopy and coronagraphy. AURA's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and a LUVOIR as well as Far-IR and an X-Ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8 or 10-m diameter fairings and ability to deliver 35 to 45-mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper reviews the mass and volume capacities of the planned SLS, discusses potential implications of these capacities for designing large space telescope missions, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope and a 12-m segmented on-axis telescope.

  11. Research on numerical algorithms for large space structures

    NASA Technical Reports Server (NTRS)

    Denman, E. D.

    1982-01-01

    Numerical algorithms for large space structures were investigated with particular emphasis on decoupling method for analysis and design. Numerous aspects of the analysis of large systems ranging from the algebraic theory to lambda matrices to identification algorithms were considered. A general treatment of the algebraic theory of lambda matrices is presented and the theory is applied to second order lambda matrices.

  12. Large space systems requirements, deployable concepts, and technology issues

    NASA Technical Reports Server (NTRS)

    Lovelace, U. M.; Garrett, L. B.

    1987-01-01

    This paper summarizes some of the future civil missions requiring large space systems technologies. Antenna, collector, and reflector missions are generalized to define a similar set of system requirements and characteristics. Although many concepts exist for both deployable and space assemblable large structures, four technically mature deployable concepts are reviewed. Two of these concepts are probably applicable to only antenna/collector missions, whereas the other two employ continuous trusses which can be configured for a broad range of planar, linear, or curved structures. Finally, technology problems or needs associated with large deployable systems are reviewed to highlight additional research and development, both analytical and experimental, required to reduce mission risk.

  13. Shuttle considerations for the design of large space structures

    NASA Technical Reports Server (NTRS)

    Roebuck, J. A., Jr.

    1980-01-01

    Shuttle related considerations (constraints and guidelines) are compiled for use by designers of a potential class of large space structures which are transported to orbit and, deployed, fabricated or assembled in space using the Space Shuttle Orbiter. Considerations of all phases of shuttle operations from launch to ground turnaround operations are presented. Design of large space structures includes design of special construction fixtures and support equipment, special stowage cradles or pallets, special checkout maintenance, and monitoring equipment, and planning for packaging into the orbiter of all additional provisions and supplies chargeable to payload. Checklists of design issues, Shuttle capabilities constraints and guidelines, as well as general explanatory material and references to source documents are included.

  14. Critical requirements for the design of large space structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1981-01-01

    The requirements for the design of a large space structure which will be deployed, erected, assembled or fabricated in space are delineated in terms of operational loads, stiffness requirements, structure-control interaction, deformations, precision requirements and member slenderness. Design examples for a truss antenna reflector, interorbit propulsion loads and free-flying solar reflectors are given. It is concluded that the demand for dimensional accuracy and stability form the primary requirements.

  15. Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2013-01-01

    Accomplishments include: Assembled outstanding team from academia, industry and government with expertise in science and space telescope engineering. Derived engineering specifications for monolithic primary mirror from science measurement needs & implementation constraints. Pursuing long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Successfully demonstrated capability to make 0.5 m deep mirror substrate and polish it to UVOIR traceable figure specification.

  16. Large space systems technology electronics: Data and power distribution

    NASA Technical Reports Server (NTRS)

    Dunbar, W. G.

    1980-01-01

    The development of hardware technology and manufacturing techniques required to meet space platform and antenna system needs in the 1980s is discussed. Preliminary designs for manned and automatically assembled space power system cables, connectors, and grounding and bonding materials and techniques are reviewed. Connector concepts, grounding design requirements, and bonding requirements are discussed. The problem of particulate debris contamination for large structure spacecraft is addressed.

  17. Large space observatories of the 21st century

    NASA Astrophysics Data System (ADS)

    Nein, M.; Howell, J.; Morgan, S.; de Sanctis, C.; Koch, D.

    1987-01-01

    Early in the 21st century, advanced space telescopes will be readied to continue the astronomical observations of the Great Observatories currently under development. This paper describes representative concepts from the very large UV/optical and gamma-ray telescopes under study by NASA, the scientific community, and industry. These studies demonstrate that historical approaches to improving the resolution and sensitivity of space telescopes have reached technology barriers which can only be overcome by innovative solutions to the telescope design. Some of the key technology issues which are guiding the approaches for advanced space telescopes are discussed, and arguments are presented that enabling technology development for these future systems must commence now.

  18. Note on dynamic response of large space structures

    NASA Astrophysics Data System (ADS)

    Elishakoff, I.; Abramovich, H.

    1992-07-01

    The dynamic behavior of large space structures, modeled as a Bresse-Timoshenko beam, was analyzed using the Bresse-Timoshenko beam model, but with the 4th-order derivative of the beam deflection with respect to time not included in the dynamical equations. In particular, the forced vibration response of symmetric large space structures was calculated for various parameters of the system. It is shown that a direct modal analysis yielding an exact solution is applicable due to the absence of the 4th-order time derivative in the Bresse-Timoshenko beam equations.

  19. Structural dynamics and control of large space structures. [conference

    NASA Technical Reports Server (NTRS)

    Lightner, E. B. (Compiler)

    1981-01-01

    The focus of the workshop was the basic research program assembled by LaRC to address the fundamental technology deficiencies that were identified in several studies on large space systems (LSS) conducted by NASA in the last several years. The staffs of the respective participants were assembled at the workshop to review the current state of research in the control technology for large structural systems and to plan the efforts that would be pursued by their respective organizations.

  20. A technology development program for large space antennas

    NASA Technical Reports Server (NTRS)

    Russell, R. A.; Campbell, T. G.; Freeland, R. E.

    1980-01-01

    Recent studies sponsored by NASA and United States industry indicate a need for technology to handle large space-based antenna systems. These systems will require apertures of up to 100 m and more in order to be capable of radio frequency operation up to Ku-band for communications, earth observations, and radio astronomy applications. They must also be cost-effective and compatible with the Space Transportation System. Selection criteria for the antennas which include such considerations as surface precision in the intended service environment and mechanical packaging efficiency, are enumerated. Space testing of the antennas will be carried out as part of NASA's Large Space Systems Technology (LSST) Program, which will be continued through fiscal year 1984. Deployable antennas have been selected for development by the LSST Program. The maturity of this class of antennas is such that a significant number of near-term space based applications will be satisfied (mobile communications, submillimeter radio astronomy, orbiting deep space relay station ODSRS, orbiting VLBI, earth-looking radiometry). Two antenna concepts selected for development are the offset wrap-rib configuration and the maypole (hoop/column) configuration with details for these concepts presented.

  1. Development of space stable thermal control coatings for use on large space vehicles

    NASA Technical Reports Server (NTRS)

    Gilligan, J. E.

    1972-01-01

    A reserach project to develop space stable thermal control coatings for large surfaces is discussed. Four major tasks are considered: (1) pigment development, (2) binder development, (3) environmental effects evaluations, and (4) general coatings investigations.

  2. NASA/MSFC Large Space Structures Ground Test Facility

    NASA Technical Reports Server (NTRS)

    Jones, Victoria L.; Waites, Henry B.

    1990-01-01

    The NASA/MFSC Large Space Structures Ground Test Facility (LSS GTF) is described in terms of the testing, evaluation, and implementation of control and system identification techniques for typical large space structures. The GTF comprises Control, Astrophysics, and Structures Experiment in Space (CASES) GTF which is being developed and the operational Single Structure Control (SSC) laboratory (an LSS flexible beam suspended vertically with sensor and actuator systems, a real-time computer system, a disturbance system, and an optical pointing system). The configuration of the laboratory and the systems used are set forth in terms of monitoring simulated disturbances. The Shuttle-based CASES experiment involves a 105-foot boom as part of an X-ray experiment, and the control of this structure will be tested at the CASES GTF. The actuation, measurement, sensor, and computer systems are described, and the configuration of the GTF is given.

  3. 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.

  4. Methodology for evaluating modular assembly of large space platforms

    NASA Technical Reports Server (NTRS)

    Smith, Jeffrey H.; Wertz, Julie; Caroff, Lawrence

    2006-01-01

    This paper presents a methodology for analytically comparing approaches to modular assembly of large space platforms. the methodology combines a physical model of the modules, a life-cycle cost model, and a risk model to capture influential trade-offs.

  5. Residual mode filters and adaptive control in large space structures

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Balas, Mark J.

    1989-01-01

    One of the most difficult problems in controlling large systems and structures is compensating for the destructive interaction which can occur between the reduced-order model (ROM) of the plant, which is used by the controller, and the unmodeled dynamics of the plant, often called the residual modes. The problem is more significant in the case of large space structures because their naturally light damping and high performance requirements lead to more frequent, destructive residual mode interaction (RMI). Using the design/compensation technique of residual mode filters (RMF's), effective compensation of RMI can be accomplished in a straightforward manner when using linear controllers. The use of RMF's has been shown to be effective for a variety of large structures, including a space-based laser and infinite dimensional systems. However, the dynamics of space structures is often uncertain and may even change over time due to on-orbit erosion from space debris and corrosive chemicals in the upper atmosphere. In this case, adaptive control can be extremely beneficial in meeting the performance requirements of the structure. Adaptive control for large structures is also based on ROM's and so destructive RMI may occur. Unfortunately, adaptive control is inherently nonlinear, and therefore the known results of RMF's cannot be applied. The purpose is to present the results of new research showing the effects of RMI when using adaptive control and the work which will hopefully lead to RMF compensation of this problem.

  6. Low-authority control synthesis for large space structures

    NASA Technical Reports Server (NTRS)

    Aubrun, J. N.; Margulies, G.

    1982-01-01

    The control of vibrations of large space structures by distributed sensors and actuators is studied. A procedure is developed for calculating the feedback loop gains required to achieve specified amounts of damping. For moderate damping (Low Authority Control) the procedure is purely algebraic, but it can be applied iteratively when larger amounts of damping are required and is generalized for arbitrary time invariant systems.

  7. Active control of large space structures: An introduction and overview

    NASA Technical Reports Server (NTRS)

    Doane, G. B., III; Tollison, D. K.; Waites, H. B.

    1985-01-01

    An overview of the large space structure (LSS) control system design problem is presented. The LSS is defined as a class of system, and LSS modeling techniques are discussed. Model truncation, control system objectives, current control law design techniques, and particular problem areas are discussed.

  8. Large space telescope, phase A. Volume 4: Scientific instrument package

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The design and characteristics of the scientific instrument package for the Large Space Telescope are discussed. The subjects include: (1) general scientific objectives, (2) package system analysis, (3) scientific instrumentation, (4) imaging photoelectric sensors, (5) environmental considerations, and (6) reliability and maintainability.

  9. A Warm Magnetoactive Plasma in a Large Volume of Space

    NASA Technical Reports Server (NTRS)

    Heiles, C.

    1984-01-01

    A diffuse ionized warm gas fills a large volume of space in the general direction of Radio Loop II. There are three types of observational evidence: Faraday rotation measures (RM's) of extragalactic sources; emission measures (EM's) derived from the H alpha emission line in the diffuse interstellar medium; and magnetic field strengths in HI clouds derived from Zeeman splitting observations.

  10. Scientific Instrument Package for the large space telescope (SIP)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The feasibility of a scientific instrument package (SIP) that will satisfy the requirements of the large space telescope was established. A reference configuration serving as a study model and data which will aid in the trade-off studies leading to the final design configuration are reported.

  11. Eyeglass: A Very Large Aperture Diffractive Space Telescope

    SciTech Connect

    Hyde, R; Dixit, S; Weisberg, A; Rushford, M

    2002-07-29

    Eyeglass is a very large aperture (25-100 meter) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope's large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently fieldable (lightweight and flat, hence packagable and deployable) and virtually eliminates the traditional, very tight, surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope's eyepiece. The Eyeglass can provide diffraction-limited imaging with either single-band, multiband, or continuous spectral coverage. Broadband diffractive telescopes have been built at LLNL and have demonstrated diffraction-limited performance over a 40% spectral bandwidth (0.48-0.72 {micro}m). As one approach to package a large aperture for launch, a foldable lens has been built and demonstrated. A 75 cm aperture diffractive lens was constructed from 6 panels of 1 m thick silica; it achieved diffraction-limited performance both before and after folding. This multiple panel, folding lens, approach is currently being scaled-up at LLNL. We are building a 5 meter aperture foldable lens, involving 72 panels of 700 {micro}m thick glass sheets, diffractively patterned to operate as coherent f/50 lens.

  12. Large space telescope, phase A. Volume 5: Support systems module

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development and characteristics of the support systems module for the Large Space Telescope are discussed. The following systems and described: (1) thermal control, (2) electrical, (3) communication and data landing, (4) attitude control system, and (5) structural features. Analyses of maintainability and reliability considerations are included.

  13. In-space production of large space systems from extraterrestrial materials: A program implementation model

    NASA Technical Reports Server (NTRS)

    Vontiesenhausen, G. F.

    1977-01-01

    A program implementation model is presented which covers the in-space construction of certain large space systems from extraterrestrial materials. The model includes descriptions of major program elements and subelements and their operational requirements and technology readiness requirements. It provides a structure for future analysis and development.

  14. Solar furnace satellite for large diameter crystal growth in space

    NASA Technical Reports Server (NTRS)

    Overfelt, Tony; Wells, Mark; Blake, John

    1993-01-01

    Investigators worldwide are preparing experiments to test the influence of low gravity found in space on the growth of many crystalline materials. However, power limitations prevent existing space crystal growth furnaces from being able to process samples any larger than about 2 cm, and in addition, the background microgravity levels found on the Space Shuttle are not low enough to significantly benefit samples much larger than 2 cm. This paper describes a novel concept of a free-flying platform utilizing well-established solar furnace technology to enable materials processing in space experiments on large-diameter crystals. The conceptual design of this Solar Furnace Satellite is described along with its operational scenario and the anticipated g levels.

  15. Formation metrology and control for large separated optics space telescopes

    NASA Technical Reports Server (NTRS)

    Mettler, E.; Quadrelli, M.; Breckenridge, W.

    2002-01-01

    In this paper we present formation flying performance analysis initial results for a representative large space telescope composed of separated optical elements [Mett 02]. A virtual-structure construct (an equivalent rigid body) is created by unique metrology and control that combines both centralized and decentralized methods. The formation may be in orbit at GEO for super-resolution Earth observation, as in the case of Figure 1, or it may be in an Earth-trailing orbit for astrophysics, Figure 2. Extended applications are envisioned for exo-solar planet interferometric imaging by a formation of very large separated optics telescopes, Figure 3. Space telescopes, with such large apertures and f/10 to f/100 optics, are not feasible if connected by massive metering structures. Instead, the new virtual-structure paradigm of information and control connectivity between the formation elements provides the necessary spatial rigidity and alignment precision for the telescope.

  16. Discharge transient coupling in large space power systems

    NASA Technical Reports Server (NTRS)

    Stevens, N. John; Stillwell, R. P.

    1990-01-01

    Experiments have shown that plasma environments can induce discharges in solar arrays. These plasmas simulate the environments found in low earth orbits where current plans call for operation of very large power systems. The discharges could be large enough to couple into the power system and possibly disrupt operations. Here, the general concepts of the discharge mechanism and the techniques of coupling are discussed. Data from both ground and flight experiments are reviewed to obtain an expected basis for the interactions. These concepts were applied to the Space Station solar array and distribution system as an example of the large space power system. The effect of discharges was found to be a function of the discharge site. For most sites in the array discharges would not seriously impact performance. One location at the negative end of the array was identified as a position where discharges could couple to charge stored in system capacitors. This latter case could impact performance.

  17. 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.

  18. Suspension systems for ground testing large space structures

    NASA Technical Reports Server (NTRS)

    Gold, Ronald R.; Friedman, Inger P.; Reed, Wilmer H., III; Hallauer, W. L.

    1990-01-01

    A research program is documented for the development of improved suspension techniques for ground vibration testing of large, flexible space structures. The suspension system must support the weight of the structure and simultaneously allow simulation of the unconstrained rigid-body movement as in the space environment. Exploratory analytical and experimental studies were conducted for suspension systems designed to provide minimum vertical, horizontal, and rotational degrees of freedom. The effects of active feedback control added to the passive system were also investigated. An experimental suspension apparatus was designed, fabricated, and tested. This test apparatus included a zero spring rate mechanism (ZSRM) designed to support a range of weights from 50 to 300 lbs and provide vertical suspension mode frequencies less than 0.1 Hz. The lateral suspension consisted of a pendulum suspended from a moving cart (linear bearing) which served to increase the effective length of the pendulum. The torsion suspension concept involved dual pendulum cables attached from above to a pivoting support (bicycle wheel). A simple test structure having variable weight and stiffness characteristics was used to simulate the vibration characteristics of a large space structure. The suspension hardware for the individual degrees of freedom was analyzed and tested separately and then combined to achieve a 3 degree of freedom suspension system. Results from the exploratory studies should provide useful guidelines for the development of future suspension systems for ground vibration testing of large space structures.

  19. Orbital transfer of large space structures with nuclear electric rockets

    NASA Technical Reports Server (NTRS)

    Silva, T. H.; Byers, D. C.

    1980-01-01

    This paper discusses the potential application of electric propulsion for orbit transfer of a large spacecraft structure from low earth orbit to geosynchronous altitude in a deployed configuration. The electric power was provided by the spacecraft nuclear reactor space power system on a shared basis during transfer operations. Factors considered with respect to system effectiveness included nuclear power source sizing, electric propulsion thruster concept, spacecraft deployment constraints, and orbital operations and safety. It is shown that the favorable total impulse capability inherent in electric propulsion provides a potential economic advantage over chemical propulsion orbit transfer vehicles by reducing the number of Space Shuttle flights in ground-to-orbit transportation requirements.

  20. Refurbishment of the Jet Propulsion Laboratory's Large Space Simulator

    NASA Technical Reports Server (NTRS)

    Harrell, J.; Johnson, K.

    1993-01-01

    The JPL large space simulator has recently undergone a major refurbishment to restore and enhance its capabilities to provide high fidelity space simulation. The nearly completed refurbishment has included upgrading the vacuum pumping system by replacing old oil diffusion pumps with new cryogenic and turbomolecular pumps; modernizing the entire control system to utilize computerized, distributed control technology; replacing the Xenon arc lamp power supplies with new upgraded units; refinishing the primary collimating mirror; and replacing the existing integrating lens unit and the fused quartz penetration window.

  1. Verification of large beam-type space structures

    NASA Technical Reports Server (NTRS)

    Shih, C.-F.; Chen, J. C.; Garba, J. A.

    1986-01-01

    The verification approach here proposed for large, beam-type space structures consists of a first part, which removes the gravity effect on the substructure tested and identifies its on-orbit dynamic characteristics, on the basis of ground test measurements, and a second part which develops an adequate scaling law that extrapolates the dynamic characteristics of the prototype structure by using results from the substructure. These approaches are presently demonstrated for the cases of a wrap-rib antenna's feed support structure and a candidate Space Shuttle flight experiment.

  2. Power conditioning for large dc motors for space flight applications

    NASA Technical Reports Server (NTRS)

    Veatch, Martin S.; Anderson, Paul M.; Eason, Douglas J.; Landis, David M.

    1988-01-01

    The design and performance of a prototype power-conditioning system for use with large brushless dc motors on NASA space missions are discussed in detail and illustrated with extensive diagrams, drawings, and graphs. The 5-kW 8-phase parallel module evaluated here would be suitable for use in the Space Shuttle Orbiter cargo bay. A current-balancing magnetic assembly with low distributed inductance permits high-speed current switching from a low-voltage bus as well as current balancing between parallel MOSFETs.

  3. Thermal expansion of composites: Methods and results. [large space structures

    NASA Technical Reports Server (NTRS)

    Bowles, D. E.; Tenney, D. R.

    1981-01-01

    The factors controlling the dimensional stability of various components of large space structures were investigated. Cyclic, thermal and mechanical loading were identified as the primary controlling factors of the dimensional stability of cables. For organic matrix composites, such as graphite-epoxy, it was found that these factors include moisture desorption in the space environment, thermal expansion as the structure moves from the sunlight to shadow in its orbit, mechanical loading, and microyielding of the material caused by microcracking of the matrix material. The major focus was placed on the thermal expansion of composites and in particular the development and testing of a method for its measurement.

  4. Overview of the large space systems technology program

    NASA Technical Reports Server (NTRS)

    Guastaferro, A.

    1978-01-01

    A multicenter management approach which provides the opportunity to work across many disciplines and match the roles and expertise of various NASA facilities is described for the large space system technology (LSST) program which was established to define, develop, and verify structural concepts, analyses, and design procedures for a range of sizes and configurations to be deployed, erected, or fabricated in orbit during projected space missions utilizing shuttle in the 1985 to 2000 time period. Benefits from the program include reduced costs for transporting structures having low mass, high packageability, and multimission capabilities. Technologies identified by the LSST program will contribute to the solutions of problems in other sectors of the economy.

  5. Large space antennas: A systems analysis case history

    NASA Technical Reports Server (NTRS)

    Keafer, Lloyd S. (Compiler); Lovelace, U. M. (Compiler)

    1987-01-01

    The value of systems analysis and engineering is aptly demonstrated by the work on Large Space Antennas (LSA) by the NASA Langley Spacecraft Analysis Branch. This work was accomplished over the last half-decade by augmenting traditional system engineering, analysis, and design techniques with computer-aided engineering (CAE) techniques using the Langley-developed Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) system. This report chronicles the research highlights and special systems analyses that focused the LSA work on deployable truss antennas. It notes developmental trends toward greater use of CAE techniques in their design and analysis. A look to the future envisions the application of improved systems analysis capabilities to advanced space systems such as an advanced space station or to lunar and Martian missions and human habitats.

  6. 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.

  7. Optimal control of large space structures via generalized inverse matrix

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Fang, Xiaowen

    1987-01-01

    Independent Modal Space Control (IMSC) is a control scheme that decouples the space structure into n independent second-order subsystems according to n controlled modes and controls each mode independently. It is well-known that the IMSC eliminates control and observation spillover caused when the conventional coupled modal control scheme is employed. The independent control of each mode requires that the number of actuators be equal to the number of modelled modes, which is very high for a faithful modeling of large space structures. A control scheme is proposed that allows one to use a reduced number of actuators to control all modeled modes suboptimally. In particular, the method of generalized inverse matrices is employed to implement the actuators such that the eigenvalues of the closed-loop system are as closed as possible to those specified by the optimal IMSC. Computer simulation of the proposed control scheme on a simply supported beam is given.

  8. Visualising very large phylogenetic trees in three dimensional hyperbolic space

    PubMed Central

    Hughes, Timothy; Hyun, Young; Liberles, David A

    2004-01-01

    Background Common existing phylogenetic tree visualisation tools are not able to display readable trees with more than a few thousand nodes. These existing methodologies are based in two dimensional space. Results We introduce the idea of visualising phylogenetic trees in three dimensional hyperbolic space with the Walrus graph visualisation tool and have developed a conversion tool that enables the conversion of standard phylogenetic tree formats to Walrus' format. With Walrus, it becomes possible to visualise and navigate phylogenetic trees with more than 100,000 nodes. Conclusion Walrus enables desktop visualisation of very large phylogenetic trees in 3 dimensional hyperbolic space. This application is potentially useful for visualisation of the tree of life and for functional genomics derivatives, like The Adaptive Evolution Database (TAED). PMID:15117420

  9. Visual Data Mining of Large, Multivariate Space-Time Data

    NASA Astrophysics Data System (ADS)

    Cook, D.

    2001-12-01

    Interest in understanding global climate change is generating monitoring efforts that yield a huge amount of multivariate space-time data. While analytical methods for univariate space-time data may be mature and substantial, methods for multivariate space-time data analysis are still in their infancy. The urgency of understanding climate change on a global scale begs for input from data analysts, and to work effectively they need new tools to explore multivariate aspects of climate. This talk describes interactive and dynamic visual tools for mining information from multivariate space-time data. Methods for small amounts of data will be discussed, followed by approaches to scaling up methods for large quantities of data. We focus on the ``multiple views'' approach for viewing multivariate data, and how these extend to include space-time contextual information. We also will describe dynamic graphics methods such as tours in the space-time context. Data mining is the current terminology for exploratory analyses of data, typically associated with large databases. Exploratory analysis has a goal of finding anomalies, quirks and deviations from a trend, and basically extracting unexpected information from data. It oft-times emphasizes model-free methods, although model-based approaches are also integral components to the analysis process. Visual data mining concentrates on the use of visual tools in the exploratory process. As such it often involves highly interactive and dynamic graphics environments which facilitate quick queries and visual responses. Visual methods are especially important in exploratory analysis because they provide an interface for using the human eye to digest complex information. A good plot can convey far more information than a numerical summary. Visual tools enhance the chances of discovering the unexpected, and detecting the anomalous events.

  10. Recent advances in structural dynamics of large space structures

    NASA Technical Reports Server (NTRS)

    Pinson, Larry D.

    1987-01-01

    Recent progress in the area of structural dynamics of large space structures is reviewed. Topics include system identification, large angle slewing of flexible structures, definition of scaling limitations in structural models, and recent results on a tension-stabilized antenna concept known as the hoop-column. Increasingly complex laboratory experiments guide most of the activities leading to realistic technological developments. Theoretical progress in system identification based on system realization theory resulting in unification of several methods is reviewed. Experimental results from implementation of a theoretical large-angle slewing control approach are shown. Status and results of the development of a research computer program for analysis of the transient dynamics of large angle motion of flexible structures are presented. Correlation of results from analysis and vibration tests of the hoop-column antenna concepts are summarized.

  11. Recent advances in structural dynamics of large space structures

    NASA Technical Reports Server (NTRS)

    Pinson, Larry D.

    1987-01-01

    Recent progress in the area of structural dynamics of large space structures is reviewed. Topics include system identification, large angle slewing of flexible structures, definition of scaling limitations in structural models, and recent results on a tension-stabilized antenna concept known as the hoop-column. Increasingly complex laboratory experiments guide most of the activities leading to realistic technological developments. Theoretical progress in system identification based on system realization theory resulting in unification of several methods is reviewed. Experimental results from implementation of a theoretical large-angle slewing control approach are shown. Status and results of the development of a research computer program for analysis of the transient dynamics of large angle motion of flexible structures are presented. Correlation of results from analysis and vibration tests of the hoop-column antenna concept are summarized.

  12. Lagrangian space consistency relation for large scale structure

    NASA Astrophysics Data System (ADS)

    Horn, Bart; Hui, Lam; Xiao, Xiao

    2015-09-01

    Consistency relations, which relate the squeezed limit of an (N+1)-point correlation function to an N-point function, are non-perturbative symmetry statements that hold even if the associated high momentum modes are deep in the nonlinear regime and astrophysically complex. Recently, Kehagias & Riotto and Peloso & Pietroni discovered a consistency relation applicable to large scale structure. We show that this can be recast into a simple physical statement in Lagrangian space: that the squeezed correlation function (suitably normalized) vanishes. This holds regardless of whether the correlation observables are at the same time or not, and regardless of whether multiple-streaming is present. The simplicity of this statement suggests that an analytic understanding of large scale structure in the nonlinear regime may be particularly promising in Lagrangian space.

  13. Integrated structure electromagnetic optimization of large space antenna reflectors

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.; Adelman, Howard M.; Bailey, M. C.

    1987-01-01

    The requirements for extremely precise and powerful large space antenna reflectors have motivated the development of a procedure for shape control of the reflector surface. A mathematical optimization procedure has been developed which improves antenna performance while minimizing necessary shape correction effort. In contrast to previous work which proposed controlling the rms distortion error of the surface thereby indirectly improving antenna performance, the current work includes electromagnetic (EM) performance calculations as an integral of the control procedure. The application of the procedure to a radiometer design with a tetrahedral truss backup structure demonstrates the potential for significant improvement. The results indicate the benefit of including EM performance calculations in procedures for shape control of large space antenna reflectors.

  14. Advanced actuators for the control of large space structures

    NASA Technical Reports Server (NTRS)

    Downer, James; Hockney, Richard; Johnson, Bruce; Misovec, Kathleen

    1993-01-01

    The objective of this research was to develop advanced six-degree-of-freedom actuators employing magnetic suspensions suitable for the control of structural vibrations in large space structures. The advanced actuators consist of a magnetically suspended mass that has three-degrees-of-freedom in both translation and rotation. The most promising of these actuators featured a rotating suspended mass providing structural control torques in a manner similar to a control moment gyro (CMG). These actuators employ large-angle-magnetic suspensions that allow gimballing of the suspended mass without mechanical gimbals. Design definitions and sizing algorithms for these CMG type as well as angular reaction mass actuators based on multi-degree-of-freedom magnetic suspensions were developed. The performance of these actuators was analytically compared with conventional reaction mass actuators for a simple space structure model.

  15. Large-viewing-angle electroholography by space projection

    NASA Astrophysics Data System (ADS)

    Sato, Koki; Obana, Kazuki; Okumura, Toshimichi; Kanaoka, Takumi; Nishikawa, Satoko; Takano, Kunihiko

    2004-06-01

    The specification of hologram image is the full parallax 3D image. In this case we can get more natural 3D image because focusing and convergence are coincident each other. We try to get practical electro-holography system because for conventional electro-holography the image viewing angle is very small. This is due to the limited display pixel size. Now we are developing new method for large viewing angle by space projection method. White color laser is irradiated to single DMD panel ( time shared CGH of RGB three colors ). 3D space screen constructed by very small water particle is used to reconstruct the 3D image with large viewing angle by scattering of water particle.

  16. Shape determination and control for large space structures

    NASA Technical Reports Server (NTRS)

    Weeks, C. J.

    1981-01-01

    An integral operator approach is used to derive solutions to static shape determination and control problems associated with large space structures. Problem assumptions include a linear self-adjoint system model, observations and control forces at discrete points, and performance criteria for the comparison of estimates or control forms. Results are illustrated by simulations in the one dimensional case with a flexible beam model, and in the multidimensional case with a finite model of a large space antenna. Modal expansions for terms in the solution algorithms are presented, using modes from the static or associated dynamic mode. These expansions provide approximated solutions in the event that a used form analytical solution to the system boundary value problem is not available.

  17. A perspective of power management for large space platforms

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Graves, J.

    1982-01-01

    NASA and military applications for high power spacecraft are presently being planned. A perspective of autonomous power management for low earth orbit large space platforms is presented. A multichannel 250 kWe utility-type power subsystem is used as a baseline system. The need for automation is reviewed, based on power subsystem complexity, survivability requirements, and cost benefits. On-board versus ground management is discussed with respect to these needs. In addition, the utilization of autonomous power management to enable technology readiness of large complex power subsystems is described. Recommendations are made for further technology thrusts.

  18. Considerations in the design of large space structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.; Macneal, R. H.; Knapp, K.; Macgillivray, C. S.

    1981-01-01

    Several analytical studies of topics relevant to the design of large space structures are presented. Topics covered are: the types and quantitative evaluation of the disturbances to which large Earth-oriented microwave reflectors would be subjected and the resulting attitude errors of such spacecraft; the influence of errors in the structural geometry of the performance of radiofrequency antennas; the effect of creasing on the flatness of tensioned reflector membrane surface; and an analysis of the statistics of damage to truss-type structures due to meteoroids.

  19. 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.

  20. A telerobotic system for automated assembly of large space structures

    NASA Technical Reports Server (NTRS)

    Rhodes, Marvin D.; Will, Ralph W.; Wise, Marion A.

    1989-01-01

    Future space missions such as polar platforms and antennas are anticipated to require large truss structures as their primary support system. During the past several years considerable research has been conducted to develop hardware and construction techniques suitable for astronaut assembly of truss structures in space. A research program has recently been initiated to develop the technology and to demonstrate the potential for automated in-space assembly of large erectable structures. The initial effort will be focussed on automated assembly of a tetrahedral truss composed of 2-meter members. The facility is designed as a ground based system to permit evaluation of assembly concepts and was not designed for space qualification. The system is intended to be used as a tool from which more sophisticated procedures and operations can be developed. The facility description includes a truss structure, motionbases and a robot arm equipped with an end effector. Other considerations and requirements of the structural assembly describe computer control systems to monitor and control the operations of the assembly facility.

  1. Controlled multibody dynamics simulation for large space structures

    NASA Technical Reports Server (NTRS)

    Housner, J. M.; Wu, S. C.; Chang, C. W.

    1989-01-01

    Multibody dynamics discipline, and dynamic simulation in control structure interaction (CSI) design are discussed. The use, capabilities, and architecture of the Large Angle Transient Dynamics (LATDYN) code as a simulation tool are explained. A generic joint body with various types of hinge connections; finite element and element coordinate systems; results of a flexible beam spin-up on a plane; mini-mast deployment; space crane and robotic slewing manipulations; a potential CSI test article; and multibody benchmark experiments are also described.

  2. Planning Assembly Of Large Truss Structures In Outer Space

    NASA Technical Reports Server (NTRS)

    De Mello, Luiz S. Homem; Desai, Rajiv S.

    1992-01-01

    Report dicusses developmental algorithm used in systematic planning of sequences of operations in which large truss structures assembled in outer space. Assembly sequence represented by directed graph called "assembly graph", in which each arc represents joining of two parts or subassemblies. Algorithm generates assembly graph, working backward from state of complete assembly to initial state, in which all parts disassembled. Working backward more efficient than working forward because it avoids intermediate dead ends.

  3. Composite material technology requirements for large precision space structures

    NASA Technical Reports Server (NTRS)

    Mcelroy, P. M.; Helms, R. G.

    1984-01-01

    The development of dimensionally stable, precision composite structures has been recognized as a high risk technology driver in NASA's continuing large space structures research. Attempts are being made to understand the influences controlling thermal performance in such composites, and specifically in composite sandwich panels. The necessary tools for such composite panels' deployment, the experimental verification of analytical predictions, and the demonstration of technology in small scale hardware, are presently addressed.

  4. Technology for large space systems: A special bibliography with indexes

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This bibliography lists 460 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1968 and December 31, 1978. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, and flight experiments.

  5. Research on numerical algorithms for large space structures

    NASA Technical Reports Server (NTRS)

    Denman, E. D.

    1981-01-01

    Numerical algorithms for analysis and design of large space structures are investigated. The sign algorithm and its application to decoupling of differential equations are presented. The generalized sign algorithm is given and its application to several problems discussed. The Laplace transforms of matrix functions and the diagonalization procedure for a finite element equation are discussed. The diagonalization of matrix polynomials is considered. The quadrature method and Laplace transforms is discussed and the identification of linear systems by the quadrature method investigated.

  6. Study of composites as substrate materials in large space telescopes

    NASA Technical Reports Server (NTRS)

    Sharma, A. V.

    1979-01-01

    Nonmetallic composites such as the graphite/epoxy system were investigated as possible substrates for the primary mirror of the large space telescope. The possible use of fiber reinforced metal matrix composites was reviewed in the literature. Problems arising out of the use of composites as substrate materials such as grinding, polishing, adherence of reflective coatings, rigidity of substrate, hygrospcopici tendency of the composites, thermal and temporal stability and other related problems were examined.

  7. On the possibility of large axion moduli spaces

    SciTech Connect

    Rudelius, Tom

    2015-04-28

    We study the diameters of axion moduli spaces, focusing primarily on type IIB compactifications on Calabi-Yau three-folds. In this case, we derive a stringent bound on the diameter in the large volume region of parameter space for Calabi-Yaus with simplicial Kähler cone. This bound can be violated by Calabi-Yaus with non-simplicial Kähler cones, but additional contributions are introduced to the effective action which can restrict the field range accessible to the axions. We perform a statistical analysis of simulated moduli spaces, finding in all cases that these additional contributions restrict the diameter so that these moduli spaces are no more likely to yield successful inflation than those with simplicial Kähler cone or with far fewer axions. Further heuristic arguments for axions in other corners of the duality web suggest that the difficulty observed in http://dx.doi.org/10.1088/1475-7516/2003/06/001 of finding an axion decay constant parametrically larger than M{sub p} applies not only to individual axions, but to the diagonals of axion moduli space as well. This observation is shown to follow from the weak gravity conjecture of http://dx.doi.org/10.1088/1126-6708/2007/06/060, so it likely applies not only to axions in string theory, but also to axions in any consistent theory of quantum gravity.

  8. Conceptual study of the damping of large space structures using large-stroke adaptive stiffness cables

    NASA Technical Reports Server (NTRS)

    Thorwald, Gregory; Mikulas, Martin M., Jr.

    1992-01-01

    The concept of a large-stroke adaptive stiffness cable-device for damping control of space structures with large mass is introduced. The cable is used to provide damping in several examples, and its performance is shown through numerical simulation results. Displacement and velocity information of how the structure moves is used to determine when to modify the cable's stiffness in order to provide a damping force.

  9. Large space structures and systems in the space station era: A bibliography with indexes (supplement 03)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Bibliographies and abstracts are listed for 1221 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1991 and June 30, 1991. Topics covered include large space structures and systems, space stations, extravehicular activity, thermal environments and control, tethering, spacecraft power supplies, structural concepts and control systems, electronics, advanced materials, propulsion, policies and international cooperation, vibration and dynamic controls, robotics and remote operations, data and communication systems, electric power generation, space commercialization, orbital transfer, and human factors engineering.

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

    NASA Technical Reports Server (NTRS)

    Gates, R. M.; Reid, G.

    1984-01-01

    The objectives studied are the definition of the tested role of an early Space Station for the construction of large space structures. This is accomplished by defining the LSS technology development missions (TDMs) identified in phase 1. Design and operations trade studies are used to identify the best structural concepts and procedures for each TDMs. Details of the TDM designs are then developed along with their operational requirements. Space Station resources required for each mission, both human and physical, are identified. The costs and development schedules for the TDMs provide an indication of the programs needed to develop these missions.

  11. Novel In-Space Manufacturing Concepts for the Development of Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Mooney, James T.; Reardon, Patrick; Gregory Don; Manning, Andrew; Blackmon, Jim; Howsman, Tom; Williams, Philip; Brantley, Whitt; Rakoczy, John; Herren, Kenneth

    2006-01-01

    There is a continuous demand for larger, lighter, and higher quality telescopes. Over the past several decades, we have seen the evolution from launchable 2 meter-class telescopes (such as Hubble), to today s demand for deployable 6 meter-class telescopes (such as JWST), to tomorrow s need for up to 150 meter-class telescopes. As the apertures continue to grow, it will become much more difficult and expensive to launch assembled telescope structures. To address this issue, we are seeing the emergence of new novel structural concepts, such as inflatable structures and membrane optics. While these structural concepts do show promise, it is very difficult to achieve and maintain high surface figure quality. Another potential solution to develop large space telescopes is to move the fabrication facility into space and launch the raw materials. In this paper we present initial in-space manufacturing concepts to enable the development of large telescopes. This includes novel approaches for the fabrication of both the optical elements and the telescope support structure. We will also discuss potential optical designs for large space telescopes and describe their relation to the fabrication methods. These concepts are being developed to meet the demanding requirements of DARPA s LASSO (Large Aperture Space Surveillance Optic) program which currently requires a 150 meter optical aperture with a 17 degree field of view.

  12. Static shape determination and control for large space structures. I - The flexible beam. II - A large space antenna

    NASA Technical Reports Server (NTRS)

    Weeks, C. J.

    1984-01-01

    A method for determining and controlling the shape of large, continuous space structures by means of discrete or pointwise observations and control devices is presented. The general linear boundary value problem satisfied by a one-dimensional shape function is defined, and the existence of solutions is studied. The static shape control problems for one-dimensional systems with and without rigid body modes and the static shape estimation problem are presented and solved. Eigenfunction expansions are presented which provide approximations to the algorithm terms when the associated Green's function is not known. An integral operator approach is applied to the multidimensional static problem, and the results are illustrated with a finite element model of the disk of a large space antenna which assumes no rigid body modes. It is shown that the shape control algorithm must be modified for systems with rigid body modes.

  13. Inflatable Hangar for Assembly of Large Structures in Space

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian H.

    2012-01-01

    The NASA Human Space Flight program is interested in projects where humans, beyond low-Earth orbit (LEO), can make an important and unique contribution that cannot be reasonably accomplished purely by robotic means, and is commensurate with the effort and cost associated with human spaceflight. Robotic space telescope missions have been conceived and launched as completed assemblies (e.g., Hubble) or as jack-in-the-box one-time deployments (e.g., James Webb). If it were possible to assemble components of a very large telescope from one or two launches into a telescope that was vastly greater in light-gathering power and resolution, that would constitute a breakthrough. Large telescopes on Earth, like all one-off precision assembly tasks, are done by humans. Humans in shirtsleeves (or cleanroom bunny suits) can perform tasks of remarkable dexterity and precision. Unfortunately, astronauts in pressure suits cannot perform such dexterous and precise tasks because of the limitations of the pressurized gloves. If a large, inflatable hangar were placed in high orbit, along with all the components needed for a large assembly such as a large telescope, then humans in bunny suits could perform the same sorts of extremely precise and dexterous assembly that they could be expected to perform on Earth. Calculations show that such an inflatable hangar, and the necessary gas to make it safe to occupy by shirtsleeves humans wearing oxygen masks, fits within the mass and volume limitations of the proposed "Space Launch System" heavy-lift rocket. A second launch could bring up all the components of an approximately 100-meter-diameter or larger telescope. A large [200 ft (approximately 61 m) in diameter] inflated fabric sphere (or hangar) would contain four humans in bunny suits. The sphere would contain sufficient atmospheric pressure so that spacesuits would not be necessary [about 3.2 psi (approximately 22 kPa)]. The humans would require only oxygen masks and small backpacks

  14. A robot in space as a large space structures control experiment

    NASA Technical Reports Server (NTRS)

    Gran, R.

    1983-01-01

    The control systems design issues for large space structures can be addressed by a robotics experiment which defines a teleoperator or a robot or uses the RMS. The robotics control demonstration brings the large space structures control technology to an effective state of readiness and provides a useful robot when the experiment is finished. Three major options in such an experiment are the RMS, a flexible arm that is going to be put on the Shuttle for other reasons, or a dexetrous manipulator or teleoperator.

  15. The dynamics and control of large flexible space structures

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Kumar, V. K.; Krishna, R.; Reddy, A. S. S. R.; Diarra, C. M.

    1983-01-01

    Large, flexible orbiting systems proposed for possible use in communications, electronic orbital based mail systems, and solar energy collection are discussed. The size and low weight to area ratio of such systems indicate that system flexibility is now the main consideration in the dynamics and control problem. For such large, flexible systems, both orientation and surface shape control will often be required. A conceptual development plan of a system software capability for use in analysis of the dynamics and control of large space structures technology (LSST) systems is discussed. This concept can be subdivided into four different stages: (1) system dynamics; (2) structural dynamics; (3) application of control algorithms; and (4) simulation of environmental disturbances. Modeling the system dynamics of such systems in orbit is the most fundamental component. Solar radiation pressure effects and orbital and gravity gradient effects are discussed.

  16. Primary propulsion/large space system interaction study

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.; Dergance, R. H.; Robertson, R. I.; Wiggins, J. V.

    1981-01-01

    An interaction study was conducted between propulsion systems and large space structures to determine the effect of low thrust primary propulsion system characteristics on the mass, area, and orbit transfer characteristics of large space systems (LSS). The LSS which were considered would be deployed from the space shuttle orbiter bay in low Earth orbit, then transferred to geosynchronous equatorial orbit by their own propulsion systems. The types of structures studied were the expandable box truss, hoop and column, and wrap radial rib each with various surface mesh densities. The impact of the acceleration forces on system sizing was determined and the effects of single point, multipoint, and transient thrust applications were examined. Orbit transfer strategies were analyzed to determine the required velocity increment, burn time, trip time, and payload capability over a range of final acceleration levels. Variables considered were number of perigee burns, delivered specific impulse, and constant thrust and constant acceleration modes of propulsion. Propulsion stages were sized for four propellant combinations; oxygen/hydrogen, oxygen/methane, oxygen/kerosene, and nitrogen tetroxide/monomethylhydrazine, for pump fed and pressure fed engine systems. Two types of tankage configurations were evaluated, minimum length to maximize available payload volume and maximum performance to maximize available payload mass.

  17. Ground facility for large space structures dynamics and control verification

    NASA Technical Reports Server (NTRS)

    Waites, Henry

    1986-01-01

    NASA 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 unsured. The facility consists of an LSS test article or payload which is connected to a 3-axis angular pointing mount assembly that provides control torque commands. The angular pointing mount assembly is attached to a base excitation system which will simulate disturbances most likely to occur for Orbiter and DOD payloads. The control computer contains the calibration software, the reference systems, the alignment procedures, the telemetry software, and the control algorithms. The total system is suspended in such a fashion that the LSS test article has the characteristics common to all LSS.

  18. 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.

  19. Large area emulsion chamber experiments for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Parnell, T. A.

    1985-01-01

    Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

  20. Camera memory study for large space telescope. [charge coupled devices

    NASA Technical Reports Server (NTRS)

    Hoffman, C. P.; Brewer, J. E.; Brager, E. A.; Farnsworth, D. L.

    1975-01-01

    Specifications were developed for a memory system to be used as the storage media for camera detectors on the large space telescope (LST) satellite. Detectors with limited internal storage time such as intensities charge coupled devices and silicon intensified targets are implied. The general characteristics are reported of different approaches to the memory system with comparisons made within the guidelines set forth for the LST application. Priority ordering of comparisons is on the basis of cost, reliability, power, and physical characteristics. Specific rationales are provided for the rejection of unsuitable memory technologies. A recommended technology was selected and used to establish specifications for a breadboard memory. Procurement scheduling is provided for delivery of system breadboards in 1976, prototypes in 1978, and space qualified units in 1980.

  1. Thermal/structural design verification strategies for large space structures

    NASA Technical Reports Server (NTRS)

    Benton, David

    1988-01-01

    Requirements for space structures of increasing size, complexity, and precision have engendered a search for thermal design verification methods that do not impose unreasonable costs, that fit within the capabilities of existing facilities, and that still adequately reduce technical risk. This requires a combination of analytical and testing methods. This requires two approaches. The first is to limit thermal testing to sub-elements of the total system only in a compact configuration (i.e., not fully deployed). The second approach is to use a simplified environment to correlate analytical models with test results. These models can then be used to predict flight performance. In practice, a combination of these approaches is needed to verify the thermal/structural design of future very large space systems.

  2. Expert systems for adaptive control of large space structures

    NASA Technical Reports Server (NTRS)

    Gartrell, Charles F.

    1988-01-01

    It is expected that space systems for the future will evolve to structures of unprecedented size with associated extreme control requirements. A method is necessary that is sufficiently general to initiate stable control of a vehicle and subsequently learn the true nature of the structure. It is suggested that a suitable constructed expert system (ES) would be capable of learning by appending observations to a knowledge base. To verify that an ES can control a large space structure, numerical simulations of a simple structure subjected to periodic vibrations and the performance of a classical controllers were performed. The ES was then exercised to show its ability to truthfully mimic nominal control and to demonstrate its superiority to the classical controller, given sensor failures. An ES generating software package, The Intelligent Machine Model, was employed. It uses the pattern matching technique. Results of this program are discussed.

  3. 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. This paper discusses the performance of an SEC-vidicon with a 25 mm x 25 mm active area, MgF2 window, and bi-alkali photocathode. 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 II 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.

  4. Advanced UVOIR Mirror Technology Development for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2011-01-01

    Objective of this work is to define and initiate a long-term program to mature six inter-linked critical technologies for future UVOIR space telescope mirrors to TRL6 by 2018 so that a viable flight mission can be proposed to the 2020 Decadal Review. (1) Large-Aperture, Low Areal Density, High Stiffness Mirrors: 4 to 8 m monolithic & 8 to 16 m segmented primary mirrors require larger, thicker, stiffer substrates. (2) Support System:Large-aperture mirrors require large support systems to ensure that they survive launch and deploy on orbit in a stress-free and undistorted shape. (3) Mid/High Spatial Frequency Figure Error:A very smooth mirror is critical for producing a high-quality point spread function (PSF) for high-contrast imaging. (4) Segment Edges:Edges impact PSF for high-contrast imaging applications, contributes to stray light noise, and affects the total collecting aperture. (5) Segment-to-Segment Gap Phasing:Segment phasing is critical for producing a high-quality temporally stable PSF. (6) Integrated Model Validation:On-orbit performance is determined by mechanical and thermal stability. Future systems require validated performance models. We are pursuing multiple design paths give the science community the option to enable either a future monolithic or segmented space telescope.

  5. Investigation of Secondary Neutron Production in Large Space Vehicles for Deep Space

    NASA Technical Reports Server (NTRS)

    Rojdev, Kristina; Koontz, Steve; Reddell, Brandon; Atwell, William; Boeder, Paul

    2016-01-01

    Future NASA missions will focus on deep space and Mars surface operations with large structures necessary for transportation of crew and cargo. In addition to the challenges of manufacturing these large structures, there are added challenges from the space radiation environment and its impacts on the crew, electronics, and vehicle materials. Primary radiation from the sun (solar particle events) and from outside the solar system (galactic cosmic rays) interact with materials of the vehicle and the elements inside the vehicle. These interactions lead to the primary radiation being absorbed or producing secondary radiation (primarily neutrons). With all vehicles, the high-energy primary radiation is of most concern. However, with larger vehicles, there is more opportunity for secondary radiation production, which can be significant enough to cause concern. In a previous paper, we embarked upon our first steps toward studying neutron production from large vehicles by validating our radiation transport codes for neutron environments against flight data. The following paper will extend the previous work to focus on the deep space environment and the resulting neutron flux from large vehicles in this deep space environment.

  6. Large area low-cost space solar cell development

    NASA Technical Reports Server (NTRS)

    Barona, C. R.; Cioni, J. L.

    1982-01-01

    A development program to produce 5.9 x 5.9 cm space quality silicon solar cells with a cost goal of 30 $/W is described. Cell types investigated include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm/cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover glass simultaneously is being developed. Results for cell and array tests are given. Large solar arrays that might use cells of this type are discussed.

  7. Mission planning parameters for the Space Shuttle large format camera

    NASA Technical Reports Server (NTRS)

    Wood, G. A.

    1979-01-01

    The paper discusses the impact of various Space Shuttle mission parameters on the efficient and meaningful utilization of the large format camera (LFC) as a photographic acquisition system. Some of the LFC's vital statistics and its mounting within the Orbiter payload are described. LFC characteristics and mounting dictate certain mission parameters. The controlling parameters are orbit inclinations, launch time of year, launch time of day, orbital altitude, mission duration, overlap selection, film capacity, and climatological prediction. A mission case is evaluated relative to controlling parameters and geographical area(s) of interest.

  8. Large Space Telescope support systems module thermal control

    NASA Technical Reports Server (NTRS)

    Chapter, J. J.

    1975-01-01

    In 1982, an unmanned three-meter class Cassegrainian telescopic system referred to as the Large Space Telescope (LST) will be placed in earth orbit by the Shuttle. The LST consists of a telescope system and surrounding support structure that is referred to as the support system module (SSM). This paper summarizes the thermal control subsystem for several candidate SSM designs. Major emphasis has been given to the LST/SSM design concept that includes a thermally isolated aft cylinder compartment that contains subsystem components. Requirements, interfaces and thermal math modeling methods are presented. Analysis results demonstrate that a cold-biased thermal design using electrical heaters is promising.

  9. On the nonlinear dynamics and control of large space structures

    SciTech Connect

    Modi, V.J.

    1994-12-31

    The paper reviews, using the Lagrangian approach, dynamics of flexible multibody systems, of contemporary interest, and their control. To begin with, a relatively general formulation for studying the dynamics and control of an arbitrary spacecraft with interconnected flexible bodies is developed accounting for thermal deflection, transient system properties, shift in the center of mass, shear deformations, rotary inertias and geometric nonlinearities. A rather self-contained, comprehensive, numerical algorithm using system as well as component modes follows which is applicable to a large class of spacecraft configurations. In particular, versatility of the approach is demonstrated through the dynamics and control studies aimed at the proposed Space Station and the associated mobile manipulator system.

  10. Large space erectable structures - building block structures study

    NASA Technical Reports Server (NTRS)

    Armstrong, W. H.; Skoumal, D. E.; Straayer, J. W.

    1977-01-01

    A modular planar truss structure and a long slender boom concept identified as building block approaches to construction of large spacecraft configurations are described. The concepts are compatible in weight and volume goals with the Space Transportation System, use standard structural units, and represent high on-orbit productivity in terms of structural area or beam length. Results of structural trade studies involving static and dynamic analyses of a single module and rigid body deployment analyses to assess kinetics and kinematics of automatic deployment of the building block modules are presented.

  11. Analysis and design of ion thrusters for large space systems

    NASA Technical Reports Server (NTRS)

    James, E. L.

    1980-01-01

    This study undertakes the analysis and conceptual design of a 0.5 Newton electrostatic ion thruster suitable for use on large space system missions in the next decade. Either argon or xenon gas shall be used as propellant. A 50 cm diameter discharge chamber was selected to meet stipulated performance goals. The discharge plasma is contained at the boundary by a periodic structure of alternating permanent magnets generating a series of line cusps. Anode strips between the magnets collect Maxwellian electrons generated by a central cathode. Ion extraction utilizes either two or three grid optics at the user's choice. An extensive analysis was undertaken to investigate optics behavior in the high power environment of this large thruster. A plasma bridge neutralizer operating on inert gas provides charge neutralizing electrons to complete the design. The resulting conceptual thruster and the necessary power management and control requirements are described.

  12. Large area low-cost space solar cell development

    NASA Technical Reports Server (NTRS)

    Baraona, C. R.; Cioni, J. L.

    1982-01-01

    A development program to produce large-area (5.9 x 5.9 cm) space quality silicon solar cells with a cost goal of 30 $/watt is descibed. Five cell types under investigation include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm-cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover-glass simultaneously is being developed. A description of cell developments by Applied Solar Energy Corp., Spectrolab and Spire is included. Results are given for cell and array tests, performed by Lockheed, TRW and NASA. Future large solar arrays that might use cells of this type are discussed.

  13. The damper placement problem for large flexible space structures

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1992-01-01

    The damper placement problem for large flexible space truss structures is formulated as a combinatorial optimization problem. The objective is to determine the p truss members of the structure to replace with active (or passive) dampers so that the modal damping ratio is as large as possible for all significant modes of vibration. Equivalently, given a strain energy matrix with rows indexed on the modes and the columns indexed on the truss members, we seek to find the set of p columns such that the smallest row sum, over the p columns, is maximized. We develop a tabu search heuristic for the damper placement problems on the Controls Structures Interaction (CSI) Phase 1 Evolutionary Model (10 modes and 1507 truss members). The resulting solutions are shown to be of high quality.

  14. GLAST, the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Ritz, Steven

    2007-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to greater than 300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. With its upcoming launch in 2008, GLAST will open a new and important window on a wide variety of phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts; the origin of cosmic rays and supernova remnants; and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations and Lorentz invariance violation. In addition to the science opportunities, this talk includes a description of the instruments, the collaboration between particle physicists and astrophysicists, the opportunities for guest observers, and the mission status.

  15. Adaptive control of large space structures using recursive lattice filters

    NASA Technical Reports Server (NTRS)

    Sundararajan, N.; Goglia, G. L.

    1985-01-01

    The use of recursive lattice filters for identification and adaptive control of large space structures is studied. Lattice filters were used to identify the structural dynamics model of the flexible structures. This identification model is then used for adaptive control. Before the identified model and control laws are integrated, the identified model is passed through a series of validation procedures and only when the model passes these validation procedures is control engaged. This type of validation scheme prevents instability when the overall loop is closed. Another important area of research, namely that of robust controller synthesis, was investigated using frequency domain multivariable controller synthesis methods. The method uses the Linear Quadratic Guassian/Loop Transfer Recovery (LQG/LTR) approach to ensure stability against unmodeled higher frequency modes and achieves the desired performance.

  16. Controllability of inherently damped large flexible space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Bainum, P. M.

    1982-01-01

    Graph theoretic techniques are used to study controllability of linear systems which represent large flexible orbiting space systems with inherent damping. The controllability of the pair of matrices representing the system state and control influence matrices is assured when all states in the model are reachable in a digraph sense from at least one input and also when the term rank of a Boolean matrix whose non trivial components are based on the state and control influence matrices has a term rank of the order of the state vector. The damping matrix does not influence the required number of actuators but gives flexibility to the possibility locations of the actuators for which the system is controllable.

  17. Model verification of large structural systems. [space shuttle model response

    NASA Technical Reports Server (NTRS)

    Lee, L. T.; Hasselman, T. K.

    1978-01-01

    A computer program for the application of parameter identification on the structural dynamic models of space shuttle and other large models with hundreds of degrees of freedom is described. Finite element, dynamic, analytic, and modal models are used to represent the structural system. The interface with math models is such that output from any structural analysis program applied to any structural configuration can be used directly. Processed data from either sine-sweep tests or resonant dwell tests are directly usable. The program uses measured modal data to condition the prior analystic model so as to improve the frequency match between model and test. A Bayesian estimator generates an improved analytical model and a linear estimator is used in an iterative fashion on highly nonlinear equations. Mass and stiffness scaling parameters are generated for an improved finite element model, and the optimum set of parameters is obtained in one step.

  18. Frequency domain identification for robust large space structure control design

    NASA Technical Reports Server (NTRS)

    Yam, Y.; Bayard, D. S.; Scheid, R. E.

    1991-01-01

    A methodology is demonstrated for frequency domain identification of large space structures which systematically transforms experimental raw data into a form required for synthesizing H(infinity) controllers using modern robust control design software (e.g., Matlab Toolboxes). A unique feature of this approach is that the additive uncertainty is characterized to a specified statistic confidence rather than with hard bounds. In this study, the difference in robust performance is minimal between the two levels of confidence. In general cases, the present methodology provides a tool for performance/confidence level tradeoff studies. For simplicity, the additive uncertainty on a frequency grid is considered and the interpolation error in between grid points is neglected.

  19. Large Space Telescope - Orbital crew EV maintenance operations

    NASA Technical Reports Server (NTRS)

    Fisher, H. T.

    1975-01-01

    The paper shows that orbital EV maintenance by the crew has a tremendous impact on several areas of the program, including operations, Shuttle interfaces, support equipment rendezvous and berthing, checkout and verification, levels of servicing achievable, logistics and spares and scientific instruments in order to permit changeout and possible future refurbishment. To achieve on-orbit EV maintenance, such challenges as designing for suited-astronaut access to all subsystem equipment elements, minimization for contamination, handling of extremely sensitive instruments, development of translation techniques, and use of existing GFE and hardware must be faced early in the preliminary design and operations analysis phases. All studies to date indicate that on-orbit EV manned maintenance of the LST (Large Space Telescope) is not only feasible but can be designed to be readily within the capability of the EV functioning astronaut. Both 1-g and neutral buoyancy man-in-the-loop simulations further support this point.

  20. Coalescent simulation in continuous space: algorithms for large neighbourhood size.

    PubMed

    Kelleher, J; Etheridge, A M; Barton, N H

    2014-08-01

    Many species have an essentially continuous distribution in space, in which there are no natural divisions between randomly mating subpopulations. Yet, the standard approach to modelling these populations is to impose an arbitrary grid of demes, adjusting deme sizes and migration rates in an attempt to capture the important features of the population. Such indirect methods are required because of the failure of the classical models of isolation by distance, which have been shown to have major technical flaws. A recently introduced model of extinction and recolonisation in two dimensions solves these technical problems, and provides a rigorous technical foundation for the study of populations evolving in a spatial continuum. The coalescent process for this model is simply stated, but direct simulation is very inefficient for large neighbourhood sizes. We present efficient and exact algorithms to simulate this coalescent process for arbitrary sample sizes and numbers of loci, and analyse these algorithms in detail. PMID:24910324

  1. A Future Large-Aperture UVOIR Space Observatory: Reference Designs

    NASA Technical Reports Server (NTRS)

    Thronson, Harley; Rioux, Norman; Feinberg, Lee; Stahl, H. Philip; Redding, Dave; Jones, Andrew; Sturm, James; Collins, Christine; Liu, Alice

    2015-01-01

    Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. We describe the feasibility assessment of system thermal and dynamic stability for supporting coronagraphy. The observatory is in a Sun-Earth L2 orbit providing a stable thermal environment and excellent field of regard. Reference designs include a 36-segment 9.2 m aperture telescope that stows within a five meter diameter launch vehicle fairing. Performance needs developed under the study are traceable to a variety of reference designs including options for a monolithic primary mirror.

  2. A future large-aperture UVOIR space observatory: reference designs

    NASA Astrophysics Data System (ADS)

    Rioux, Norman; Thronson, Harley; Feinberg, Lee; Stahl, H. Philip; Redding, Dave; Jones, Andrew; Sturm, James; Collins, Christine; Liu, Alice

    2015-09-01

    Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. We describe the feasibility assessment of system thermal and dynamic stability for supporting coronagraphy. The observatory is in a Sun-Earth L2 orbit providing a stable thermal environment and excellent field of regard. Reference designs include a 36-segment 9.2 m aperture telescope that stows within a five meter diameter launch vehicle fairing. Performance needs developed under the study are traceable to a variety of reference designs including options for a monolithic primary mirror.

  3. Large area CCD image sensors for space astronomy

    NASA Technical Reports Server (NTRS)

    Schwarzschild, M.

    1979-01-01

    The Defense Advanced Research Projects Agency (DARPA) has a substantial program to develop a 2200 x 2200 pixel CCD (Charge Coupled Device) mosaic array made up of 400 individual CCD's, 110 x 110 pixels square. This type of image sensor appeared to have application in space and ground-based astronomy. Under this grant a CCD television camera system was built which was capable of operating an array of 4 CCD's to explore the suitability of the CCD's to explore the suitability of the CCD for astronomical applications. Two individual packaged CCD's were received and evaluated. Evaluation of the basic characteristics of the best individual chips was encouraging, but the manufacturer found that their yield in manufacturing this design is two low to supply sufficient CDD's for the DARPA mosaic array. The potential utility of large mosaic arrays in astronomy is still substantial and continued monitoring of the manufacturers progress in the coming year is recommended.

  4. Adaptive control of large space structures using recursive lattice filters

    NASA Technical Reports Server (NTRS)

    Goglia, G. L.

    1985-01-01

    The use of recursive lattice filters for identification and adaptive control of large space structures was studied. Lattice filters are used widely in the areas of speech and signal processing. Herein, they are used to identify the structural dynamics model of the flexible structures. This identified model is then used for adaptive control. Before the identified model and control laws are integrated, the identified model is passed through a series of validation procedures and only when the model passes these validation procedures control is engaged. This type of validation scheme prevents instability when the overall loop is closed. The results obtained from simulation were compared to those obtained from experiments. In this regard, the flexible beam and grid apparatus at the Aerospace Control Research Lab (ACRL) of NASA Langley Research Center were used as the principal candidates for carrying out the above tasks. Another important area of research, namely that of robust controller synthesis, was investigated using frequency domain multivariable controller synthesis methods.

  5. Pupil Alignment Considerations for Large, Deployable Space Telescopes

    NASA Technical Reports Server (NTRS)

    Bos, Brent J.; Ohl, Raymond G.; Kubalak, Daivd A.

    2011-01-01

    For many optical systems the properties and alignment of the internal apertures and pupils are not critical or controlled with high precision during optical system design, fabrication or assembly. In wide angle imaging systems, for instance, the entrance pupil position and orientation is typically unconstrained and varies over the system s field of view in order to optimize image quality. Aperture tolerances usually do not receive the same amount of scrutiny as optical surface aberrations or throughput characteristics because performance degradation is typically graceful with misalignment, generally only causing a slight reduction in system sensitivity due to vignetting. But for a large deployable space-based observatory like the James Webb Space Telescope (JWST), we have found that pupil alignment is a key parameter. For in addition to vignetting, JWST pupil errors cause uncertainty in the wavefront sensing process that is used to construct the observatory on-orbit. Furthermore they also open stray light paths that degrade the science return from some of the telescope s instrument channels. In response to these consequences, we have developed several pupil measurement techniques for the cryogenic vacuum test where JWST science instrument pupil alignment is verified. These approaches use pupil alignment references within the JWST science instruments; pupil imaging lenses in three science instrument channels; and unique pupil characterization features in the optical test equipment. This will allow us to verify and crosscheck the lateral pupil alignment of the JWST science instruments to approximately 1-2% of their pupil diameters.

  6. A Future Large-Aperture UVOIR Space Observatory: Study Overview

    NASA Astrophysics Data System (ADS)

    Postman, Marc; Thronson, Harley A.; Feinberg, Lee; Redding, David; Stahl, H. Philip

    2015-01-01

    The scientific drivers for very high angular resolution coupled with very high sensitivity and wavefront stability in the UV and optical wavelength regime have been well established. These include characterization of exoplanets in the habitable zones of solar type stars, probing the physical properties of the circumgalactic medium around z < 2 galaxies, and resolving stellar populations across a broad range of galactic environments. The 2010 NRC Decadal Survey and the 2013 NASA Science Mission Directorate 30-Year Roadmap identified a large-aperture UVOIR observatory as a priority future space mission. Our joint NASA GSFC/JPL/MSFC/STScI team has extended several earlier studies of the technology and engineering requirements needed to design and build a single filled aperture 10-meter class space-based telescope that can enable these ambitious scientific observations. We present here an overview of our new technical work including a brief summary of the reference science drivers as well as in-depth investigations of the viable telescope architectures, the requirements on thermal control and active wavefront control systems, and the range of possible launch configurations.

  7. Growth Chambers on the International Space Station for Large Plants

    NASA Technical Reports Server (NTRS)

    Massa, G. D.; Wheeler, R. M.; Morrow, R. C.; Levine, H. G.

    2016-01-01

    The International Space Station (ISS) now has platforms for conducting research on horticultural plant species under LED lighting, and those capabilities continue to expand. The 'Veggie' vegetable production system was deployed to the ISS as an applied research platform for food production in space. Veggie is capable of growing a wide array of horticultural crops. It was designed for low power usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nm), blue, (455 nm) and green (530 nm) LEDs. Interfacing with the light cap is an extendable bellows/baseplate for enclosing the plant canopy. A second large plant growth chamber, the Advanced Plant Habitat (APH), is will fly to the ISS in 2017. APH will be a fully controllable environment for high-quality plant physiological research. APH will control light (quality, level, and timing), temperature, CO2, relative humidity, and irrigation, while scrubbing any cabin or plant-derived ethylene and other volatile organic compounds. Additional capabilities include sensing of leaf temperature and root zone moisture, root zone temperature, and oxygen concentration. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs (4100K). There will be several internal cameras (visible and IR) to monitor and record plant growth and operations. Veggie and APH are available for research proposals.

  8. Growth Chambers on the International Space Station for Large Plants

    NASA Technical Reports Server (NTRS)

    Massa, Gioia D.; Wheeler, Raymond M.; Morrow, Robert C.; Levine, Howard G.

    2016-01-01

    The International Space Station (ISS) now has platforms for conducting research on horticultural plant species under LED (Light Emitting Diodes) lighting, and those capabilities continue to expand. The Veggie vegetable production system was deployed to the ISS as an applied research platform for food production in space. Veggie is capable of growing a wide array of horticultural crops. It was designed for low power usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nanometers), blue, (455 nanometers) and green (530 nanometers) LEDs. Interfacing with the light cap is an extendable bellowsbaseplate for enclosing the plant canopy. A second large plant growth chamber, the Advanced Plant Habitat (APH), is will fly to the ISS in 2017. APH will be a fully controllable environment for high-quality plant physiological research. APH will control light (quality, level, and timing), temperature, CO2, relative humidity, and irrigation, while scrubbing any cabin or plant-derived ethylene and other volatile organic compounds. Additional capabilities include sensing of leaf temperature and root zone moisture, root zone temperature, and oxygen concentration. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs (4100K). There will be several internal cameras (visible and IR) to monitor and record plant growth and operations. Veggie and APH are available for research proposals.

  9. Human exposure to large solar particle events in space

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.; Shinn, J. L.; Curtis, S. B.

    1992-01-01

    Whenever energetic solar protons produced by solar particle events traverse bulk matter, they undergo various nuclear and atomic collision processes which significantly alter the physical characteristics and biologically important properties of their transported radiation fields. These physical interactions and their effect on the resulting radiation field within matter are described within the context of a recently developed deterministic, coupled neutron-proton space radiation transport computer code (BRYNTRN). Using this computer code, estimates of human exposure in interplanetary space, behind nominal (2 g/sq cm) and storm shelter (20 g/sq cm) thicknesses of aluminum shielding, are made for the large solar proton event of August 1972. Included in these calculations are estimates of cumulative exposures to the skin, ocular lens, and bone marrow as a function of time during the event. Risk assessment in terms of absorbed dose and dose equivalent is discussed for these organs. Also presented are estimates of organ exposures for hypothetical, worst-case flare scenarios. The rate of dose equivalent accumulation places this situation in an interesting region of dose rate between the very low values of usual concern in terrestrial radiation environments and the high-dose-rate values prevalent in radiation therapy.

  10. Advanced Mirror Technology Development for Very Large Space Telescopes

    NASA Astrophysics Data System (ADS)

    Stahl, H. P.

    2014-01-01

    Advanced Mirror Technology Development (AMTD) is a NASA Strategic Astrophysics Technology project to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. The developed mirror technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. Just as JWST’s architecture was driven by launch vehicle, a future UVOIR mission’s architectures (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, to provide the science community with options, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We derived engineering specifications for potential future monolithic or segmented space telescopes based on science needs and implement constraints. And we are maturing six inter-linked critical technologies to enable potential future large aperture UVOIR space telescope: 1) Large-Aperture, Low Areal Density, High Stiffness Mirrors, 2) Support Systems, 3) Mid/High Spatial Frequency Figure Error, 4) Segment Edges, 5) Segment-to-Segment Gap Phasing, and 6) Integrated Model Validation Science Advisory Team and a Systems Engineering Team. We are maturing all six technologies simultaneously because all are required to make a primary mirror assembly (PMA); and, it is the PMA’s on-orbit performance which determines science return. PMA stiffness depends on substrate and support stiffness. Ability to cost-effectively eliminate mid/high spatial figure errors and polishing edges depends on substrate stiffness. On-orbit thermal and mechanical performance depends on substrate stiffness, the coefficient of thermal expansion (CTE) and thermal mass. And, segment-to-segment phasing depends on substrate & structure stiffness

  11. Space Shuttle Large Format Camera Photography And Resource Management

    NASA Astrophysics Data System (ADS)

    Greer, Jerry D.

    1988-02-01

    In October, 1984, the Space Shuttle Challenger carrying the Itek Large Format Camera took 2134 photographs of the Earth's land, oceans, and clouds. In this experiment, the precision cartographic large format camera was used to take vertical aerial photographs on a strip of film made up of four different emulsions. An exceptionally cloudy weather system in North America and Europe caused most of the primary photography sites to be obscured. Many photographs were therefore taken of secondary sites. The United States Department of Agriculture, Forest Service participated in this experiment by identifying many photographic test sites in the United States. When the mission was flown, most of the National Forests selected were obscured by clouds. The Forest Service is interested in the potential uses of the photography in resource management. To the extent possible, the photographs of the National Forests areas have been evaluated. The imagery is suitable for some management activities and is currently being used. During the evaluation, all imagery worldwide, was examined, and a list of potential uses was developed. With increased use, more applications will be developed.

  12. Effects of Turbine Spacing in Very Large Wind Farms

    NASA Astrophysics Data System (ADS)

    Andersen, Søren Juhl; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2015-11-01

    The Dynamic Wake Meandering model(DWM) by Larsen et al. (2007) is considered state of the art for modelling the wake behind a wind turbine. DWM assumes a quasi-steady wake deficit transported as a passive tracer by large atmospheric scales. The approach is also applied to wake interaction within wind farms, although certain aspects of the complex wake interaction are not captured, see Churchfield et al. (2014). Recent studies have shown how turbines introduce low frequencies in the wake, which could describe some of the shortcomings. Chamorro et al. (2015) identified three regions of different lengths scales. Iungo et al. (2013) related low frequencies to the hub vortex instability. Okulov et al. (2014) found Strouhal numbers in the far wake stemming from the rotating helical vortex core. Simulations by Andersen et al. (2013) found low frequencies to be inherent in the flow inside an infinite wind farm. LES simulations of large wind farms are performed with full aero-elastic Actuator Lines. The simulations investigate the inherent dynamics inside wind farms in the absence of atmospheric turbulence compared to cases with atmospheric turbulence. Resulting low frequency structures are inherent in wind farms for certain turbine spacings and affect both power production and loads. Funded by Danish Council for Strategic Research (grant 2104-09-067216/DSF), the Nordic Consortium on Optimization and Control of Wind Farms, and EuroTech wind project. The proprietary data for Vestas' NM80 turbine has been used.

  13. Judgments of exocentric direction in large-scale space.

    PubMed

    Kelly, Jonathan W; Loomis, Jack M; Beall, Andrew C

    2004-01-01

    Judgments of exocentric direction are quite common, especially when judging where others are looking or pointing. To investigate these judgments in large-scale space, observers were shown two targets in a large open field and were asked to judge the exocentric direction specified by the targets. The targets ranged in egocentric distance from 5 to 20 m with target-to-target angular separations of 45 degrees, 90 degrees, and 135 degrees. Observers judged exocentric direction using two methods: (i) by judging which point on a distant fence appeared collinear with the two targets, and (ii) by orienting their body in a direction parallel with the perceived line segment. In the collinearity task, observers had to imagine the line connecting the targets and then extrapolate this imagined line out to the fence. Observers indicated the perceived point of collinearity on a handheld 360 degrees panoramic cylinder representing their vista. The two judgment methods gave similar results except for a constant bias associated with the body-pointing response. Aside from this bias, the results of these two methods agree with other existing research indicating an effect of relative egocentric distance to the targets on judgment error--line segments are perceived as being rotated in depth. Additionally, verbal estimates of egocentric and exocentric distance suggest that perceived distance is not the cause for the systematic errors in judging exocentric direction. PMID:15222392

  14. Study of large adaptive arrays for space technology applications

    NASA Technical Reports Server (NTRS)

    Berkowitz, R. S.; Steinberg, B.; Powers, E.; Lim, T.

    1977-01-01

    The research in large adaptive antenna arrays for space technology applications is reported. Specifically two tasks were considered. The first was a system design study for accurate determination of the positions and the frequencies of sources radiating from the earth's surface that could be used for the rapid location of people or vehicles in distress. This system design study led to a nonrigid array about 8 km in size with means for locating the array element positions, receiving signals from the earth and determining the source locations and frequencies of the transmitting sources. It is concluded that this system design is feasible, and satisfies the desired objectives. The second task was an experiment to determine the largest earthbound array which could simulate a spaceborne experiment. It was determined that an 800 ft array would perform indistinguishably in both locations and it is estimated that one several times larger also would serve satisfactorily. In addition the power density spectrum of the phase difference fluctuations across a large array was measured. It was found that the spectrum falls off approximately as f to the minus 5/2 power.

  15. Large Space Optics: From Hubble to JWST and Beyond

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2008-01-01

    If necessity truly is the mother of invention, then advances in lightweight space mirror technology have been driven by launch vehicle mass and volume constraints. In the late 1970 s, at the start of Hubble development, the state of the art in ground based telescopes was 3 to 4 meter monolithic primary mirrors with masses of 6000 to 10,000 kg - clearly too massive for the planned space shuttle 25,000 kg capability to LEO. Necessity led Hubble to a different solution. Launch vehicle mass constraints (and cost) resulted in the development of a 2.4 meter lightweight eggcrate mirror. At 810 kg (180 kg/m2), this mirror was approximately 7.4% of HST s total 11,110 kg mass. And, the total observatory structure at 4.3 m x 13.2 m fit snuggly inside the space shuttle 4.6 m x 18.3 m payload bay. In the early 1990 s, at the start of JWST development, the state of the art in ground based telescopes was 8 meter class monolithic primary mirrors (16,000 to 23,000 kg) and 10 meter segmented mirrors (14,400 kg). Unfortunately, launch vehicles were still constrained to 4.5 meter payloads and 25,000 kg to LEO or 6,600 kg to L2. Furthermore, science now demanded a space telescope with 6 to 8 meter aperture operating at L2. Mirror technology was identified as a critical capability necessary to enable the next generation of large aperture space telescopes. Specific telescope architectures were explored via three independent design concept studies conducted during the summer of 1996 (1). These studies identified two significant architectural constraints: segmentation and areal density. Because the launch vehicle fairing payload dynamic envelop diameter is approximately 4.5 meters, the only way to launch an 8 meter class mirror is to segment it, fold it and deploy it on orbit - resulting in actuation and control requirements. And, because of launch vehicle mass limits, the primary mirror allocation was only 1000 kg - resulting in a maximum areal density of 20 kg/m2. At the inception of

  16. An adaptive identification and control scheme for large space structures

    NASA Technical Reports Server (NTRS)

    Carroll, J. V.

    1988-01-01

    A unified identification and control scheme capable of achieving space at form performance objectives under nominal or failure conditions is described. Preliminary results are also presented, showing that the methodology offers much promise for effective robust control of large space structures. The control method is a multivariable, adaptive, output predictive controller called Model Predictive Control (MPC). MPC uses a state space model and input reference trajectories of set or tracking points to adaptively generate optimum commands. For a fixed model, MPC processes commands with great efficiency, and is also highly robust. A key feature of MPC is its ability to control either nonminimum phase or open loop unstable systems. As an output controller, MPC does not explicitly require full state feedback, as do most multivariable (e.g., Linear Quadratic) methods. Its features are very useful in LSS operations, as they allow non-collocated actuators and sensors. The identification scheme is based on canonical variate analysis (CVA) of input and output data. The CVA technique is particularly suited for the measurement and identification of structural dynamic processes - that is, unsteady transient or dynamically interacting processes such as between aerodynamics and structural deformation - from short, noisy data. CVA is structured so that the identification can be done in real or near real time, using computationally stable algorithms. Modeling LSS dynamics in 1-g laboratories has always been a major impediment not only to understanding their behavior in orbit, but also to controlling it. In cases where the theoretical model is not confirmed, current methods provide few clues concerning additional dynamical relationships that are not included in the theoretical models. CVA needs no a priori model data, or structure; all statistically significant dynamical states are determined using natural, entropy-based methods. Heretofore, a major limitation in applying adaptive

  17. Inflatable Space Structures Technology Development for Large Radar Antennas

    NASA Technical Reports Server (NTRS)

    Freeland, R. E.; Helms, Richard G.; Willis, Paul B.; Mikulas, M. M.; Stuckey, Wayne; Steckel, Gary; Watson, Judith

    2004-01-01

    There has been recent interest in inflatable space-structures technology for possible applications on U.S. Department of Defense (DOD) missions because of the technology's potential for high mechanical-packaging efficiency, variable stowed geometry, and deployment reliability. In recent years, the DOD sponsored Large Radar Antenna (LRA) Program applied this new technology to a baseline concept: a rigidizable/inflatable (RI) perimeter-truss structure supporting a mesh/net parabolic reflector antenna. The program addressed: (a) truss concept development, (b) regidizable materials concepts assessment, (c) mesh/net concept selection and integration, and (d) developed potential mechanical-system performance estimates. Critical and enabling technologies were validated, most notably the orbital radiation durable regidized materials and the high modulus, inflatable-deployable truss members. These results in conjunction with conclusions from previous mechanical-packaging studies by the U.S. Defense Advanced Research Projects Agency (DARPA) Special Program Office (SPO) were the impetus for the initiation of the DARPA/SPO Innovative Space-based Antenna Technology (ISAT) Program. The sponsor's baseline concept consisted of an inflatable-deployable truss structure for support of a large number of rigid, active radar panels. The program's goal was to determine the risk associated with the application of these new RI structures to the latest in radar technologies. The approach used to define the technology maturity level of critical structural elements was to: (a) develop truss concept baseline configurations (s), (b) assess specific inflatable-rigidizable materials technologies, and (c) estimate potential mechanical performance. The results of the structures portion of the program indicated there was high risk without the essential materials technology flight experiments, but only moderate risk if the appropriate on-orbit demonstrations were performed. This paper covers both

  18. Replacing a technology - The Large Space Telescope and CCDs

    NASA Technical Reports Server (NTRS)

    Smith, R. W.; Tatarewicz, J. H.

    1985-01-01

    The technological improvements, design choices and mission goals which led to the inclusion of CCD detectors in the wide field camera of the Large Space Telescope (LST) to be launched by the STS are recounted. Consideration of CCD detectors began before CCDs had seen wide astronomical applications. During planning for the ST, in the 1960s, photographic methods and a vidicon were considered, and seemed feasible provided that periodic manual maintenance could be performed. The invention of CCDs was first reported in 1970 and by 1973 the CCDs were receiving significant attention as potential detectors instead of a vidicon, which retained its own technological challenges. The CCD format gained new emphasis when success was achieved in developments for planetary-imaging spacecraft. The rapidity of progress in CCD capabilities, coupled with the continued shortcomings of the vidicon, resulted in a finalized choice for a CCD device by 1977. The decision was also prompted by continuing commercial and military interest in CCDs, which was spurring the development of the technology and improving the sensitivities and reliability while lowering the costs.

  19. Structures-propulsion interactions and requirements. [large space structures

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.

    1982-01-01

    The effects of low-thrust primary propulsion system characteristics on the mass, area, and orbit transfer characteristics of large space systems (LSS) were determined. Three general structural classes of LSS were considered, each with a broad range of diameters and nonstructural surface densities. While transferring the deployed structure from LEO and to GEO, an acceleration range of 0.02 to 0.1 g's was found to maximize deliverable payload based on structural mass impact. After propulsion system parametric analyses considering four propellant combinations produced values for available payload mass, length and volume, a thrust level range which maximizes deliverable LSS diameter was determined corresponding to a structure and propulsion vehicle. The engine start and/or shutdown thrust transients on the last orbit transfer (apogee) burn can impose transient loads which would be greater than the steady-state loads at the burnout acceleration. The effect of the engine thrust transients on the LSS was determined from the dynamic models upon which various engine ramps were imposed.

  20. Cryogenic techniques for large superconducting magnets in space

    NASA Technical Reports Server (NTRS)

    Green, M. A.

    1989-01-01

    A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the United States Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 meters in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 meters from the magnet will approach earth's field in low earth orbit. The issue of high Tc superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside of the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: operation with a third shield cooled to 90 K with a sterling cycle cryocooler, and a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points.

  1. A Unique Hybrid Propulsion System Design for Large Space Boosters

    NASA Technical Reports Server (NTRS)

    Rodgers, Frederick C.

    1990-01-01

    A study was made of the application of hybrid rocket propulsion technology to large space boosters. Safety, reliability, cost, and performance comprised the evaluation criteria, in order of relative importance, for this study. The effort considered the so called classic hybrid design approach versus a novel approach which utilizes a fuel-rich gas generator for the fuel source. Other trades included various fuel/oxidizer combinations, pressure-fed versus pump fed oxidizer delivery systems, and reusable versus expandable booster systems. Following this initial trade study, a point design was generated. A gas generated-type fuel grain with pump fed liquid oxygen comprised the basis of this point design. This design study provided a mechanism for considering the means of implementing the gas generator approach for further defining details of the design. Subsequently, a system trade study was performed which determined the sensitivity of the design to various design parameters and predicted optimum values for these same parameters. The study concluded that a gas generator hybrid booster design offers enhanced safety and reliability over current of proposed solid booster designs while providing equal or greater performance levels. These improvements can be accomplished at considerably lower cost than for the liquid booster designs of equivalent capability.

  2. New Specimen Access Device for the Large Space Simulator

    NASA Astrophysics Data System (ADS)

    Lazzarini, P.; Ratti, F.

    2004-08-01

    The Large Space Simulator (LSS) is used to simulate in- orbit environmental conditions for spacecraft (S/C) testing. The LSS is intended to be a flexible facility: it can accommodate test articles that can differ significantly in shape and weight and carry various instruments. To improve the accessibility to the S/C inside the LSS chamber a new Specimen Access Device (SAD) has been procured. The SAD provides immediate and easy access to the S/C, thus reducing the amount of time necessary for the installations of set-ups in the LSS. The SAD has been designed as bridge crane carrying a basket to move the operator into the LSS. Such a crane moves on parallel rails on the top floor of the LSS building. The SAD is composed by three subsystems: the main bridge, the trolley that moves along the main bridge and the telescopic mast. A trade off analysis has been carried out for what concerns the telescopic mast design. The choice between friction pads vs rollers, to couple the different sections of the mast, has been evaluated. The resulting design makes use of a four sections square mast, with rollers driven deployment. This design has been chosen for the higher stiffness of the mast, due to the limited number of sections, and because it reduces radically the risk of contamination related to a solution based on sliding bushings. Analyses have been performed to assess the mechanical behaviour both in static and in dynamic conditions. In particular the telescopic mast has been studied in detail to optimise its stiffness and to check the safety margins in the various operational conditions. To increase the safety of the operations an anticollision system has been implemented by positioning on the basket two kind of sensors, ultrasonic and contact ones. All the translations are regulated by inverters with acceleration and deceleration ramps controlled by a Programmable Logic Controller (PLC). An absolute encoder is installed on each motor to provide the actual position of the

  3. 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.

  4. Erectable/deployable concepts for large space system technology

    NASA Technical Reports Server (NTRS)

    Agan, W. E.

    1980-01-01

    Erectable/deployable space structure concepts particularly relating to the development of a science and applications space platform are presented. Design and operating features for an automatic coupler clevis joint, a side latching detent joint, and a module-to-module auto lock coupler are given. An analysis of the packaging characteristics of stacked subassembly, single fold, hybrid, and double fold concepts is given for various platform structure configurations. Payload carrier systems and assembly techniques are also discussed.

  5. Neutral Buoyancy Simulator - NB32 - Large Space Structure

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The Hubble Space Telescope (HST) is a cooperative program of the European Space Agency (ESA) and the National Aeronautical and Space Administration (NASA) to operate a long-lived space-based observatory; it was the flagship mission of NASA's Great Observatories program. The HST program began as an astronomical dream in the 1940s. During the 1970s and 1980s, HST was finally designed and built; and it finally became operational in the 1990s. HST was deployed into a low-Earth orbit on April 25, 1990 from the cargo bay of the Space Shuttle Discovery (STS-31). The design of the HST took into consideration its length of service and the necessity of repairs and equipment replacement by making the body modular. In doing so, subsequent shuttle missions could recover the HST, replace faulty or obsolete parts and be re-released. MSFC's Neutral Buoyancy Simulator served as the training facility for shuttle astronauts for Hubble related missions. Shown is astronaut Sharnon Lucid having her life support system being checked prior to entering the NBS to begin training on the space telescope axial scientific instrument changeout.

  6. Industry/government seminar on Large Space systems technology: Executive summary

    NASA Technical Reports Server (NTRS)

    Scala, S. M.

    1978-01-01

    The critical technology developments which the participating experts recommend as being required to support the early generation large space systems envisioned as space missions during the years 1985-2000 are summarized.

  7. Remote surface inspection system. [of large space platforms

    NASA Technical Reports Server (NTRS)

    Hayati, Samad; Balaram, J.; Seraji, Homayoun; Kim, Won S.; Tso, Kam S.

    1993-01-01

    This paper reports on an on-going research and development effort in remote surface inspection of space platforms such as the Space Station Freedom (SSF). It describes the space environment and identifies the types of damage for which to search. This paper provides an overview of the Remote Surface Inspection System that was developed to conduct proof-of-concept demonstrations and to perform experiments in a laboratory environment. Specifically, the paper describes three technology areas: (1) manipulator control for sensor placement; (2) automated non-contact inspection to detect and classify flaws; and (3) an operator interface to command the system interactively and receive raw or processed sensor data. Initial findings for the automated and human visual inspection tests are reported.

  8. SAFE II: Large systems space plasma evaluation experiment

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.; Young, L. E.; Purvis, C. K.; Stevens, N. J.

    1983-01-01

    A shuttle flight experiment, the purpose of which is to obtain space data on the interaction of a high voltage solar array with the ambient space plasma is addressed. This flight experiment is a reflight of the solar array flight experiment, SAFE, except that three active solar array panels, electron release devices and plasma diagnostics are added. This experiment, SAFE 2, evaluates power loss due to parasitic current collected by the solar array, arcing on the solar array and perturbations to the plasma which may increase power loss and disturb plasma and charged particle science acquisition.

  9. Thermal storage analysis for large manned space platforms

    NASA Technical Reports Server (NTRS)

    Lehtinen, A. M.; Sadunas, J. A.

    1985-01-01

    High electrical power and waste heat rejection is projected for future manned low earth orbit space platforms, such as Space Station. The high heat rejection, optical coating degradation, long operating life with minimum maintenance requirements pose a challenging thermal management design problem. System optimization, with respect to radiator area and weight, indicate the requirement for thermal storage. This paper examines the thermal storage benefits, determines the characteristics as applied to different TMS concepts (e.g., centralized, decentralized), and examines the similarities and differences of thermal storage integration with single-phase and two-phase systems for a study baseline 75 kWe low earth orbit platform.

  10. Integrated control of thermally distorted large space antennas

    NASA Technical Reports Server (NTRS)

    Tolson, Robert H.; Huang, Jen-Kuang

    1991-01-01

    The objective is to develop a control system design method that (1) recognizes the time dependence of the thermal distortion due to orbital motion and (2) controls variables that are directly related to far field performance for earth pointing space antennas. The first objective is accomplished by expanding the distortion into principal components that are orthogonal in space and time. The approach for the second objective is to expand the far zone electric field in a Zernike-Bessel series. The method accommodates tapered feeds and arbitrary polarizations. Simulations are performed for a geosynchronous radiometer to determine the effectiveness of the control system under variations in solar geometry, structure materials and thermal properties.

  11. Large Space Systems/Low-Thrust Propulsion Technology

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The potentially critical interactions that occur between propulsion, structures and materials, and controls for large spacecraft are considered, the technology impacts within these fields are defined and the net effect on large systems and the resulting missions is determined. Topical areas are systems/mission analysis, LSS static and dynamic characterization, and propulsion systems characterization.

  12. Adaptive structures for precision controlled large space systems

    NASA Technical Reports Server (NTRS)

    Garba, John A.; Wada, Ben K.; Fanson, James L.

    1991-01-01

    The stringent accuracy and ground test validation requirements of some of the future space missions will require new approaches in structural design. Adaptive structures, structural systems that can vary their geometric congiguration as well as their physical properties, are primary candidates for meeting the functional requirements for such missions. Research performed in the development of such adaptive structural systems is described.

  13. Frame for large self-regulated ecological system for space exploitation

    NASA Astrophysics Data System (ADS)

    Kondyurin, Alexey

    2016-07-01

    Future long term space activity with human crew requires self-regulated ecological system to provide water, air and food for crew. Modern theoretical and experimental investigation results show that a sustainable ecological system can be made, but it requires large enough area and volume, which cannot be provided with modern space ship and space station technologies. The large volume frame can be created with using of inflatable construction, which can be directly cured in space environment. Problems of the large constructions in space for self-ecological system are discussed.

  14. Large-scale quantization in space plasmas (Invited)

    NASA Astrophysics Data System (ADS)

    Livadiotis, G.; McComas, D. J.

    2013-12-01

    n plasmas, Debye screening structures correlations between particles. In our recent paper [Livadiotis & McComas, Entropy, 15, 1118; Nature, doi:10.1038/nature.2013.13159], we identify a phase-space minimum h* that connects the energy of particles within a Debye sphere to an equivalent wave frequency. In theory, there was no a priori reason to expect a single value of h* across different plasmas. However, we find that this quantity remains constant across a wide range of space plasmas, from the solar wind and the planetary magnetospheres in the inner heliosphere to the distant plasma in the inner heliosheath and the local interstellar medium. We used four independent methods to derive the value of h* 2π(1.2×0.4)×10^{-22} Js: (1) Ulysses solar wind measurements, (2) a variety of space plasmas spanning a broad range of physical properties, (3) the entropic limit emerging from statistical mechanics applied to space plasmas, (4) waiting-time distributions of explosive events in space plasmas. Finding a constant value for h* in a variety of different of systems, similar to the classical Planck constant but 12 orders of magnitude larger, reveals a possible type of new quantization in plasmas but in a larger scale. The value of h* calculated for the solar wind ion-electron plasma using Ulysses daily measurements. (a) Diagram of the smallest particle energy ɛc vs. the particle lifetime tc in a Debye sphere (log-log scale). (b) Their product, 2ɛctc, depicted as a function of heliocentric distance r. (c) Histogram of the values of log h*. Four Different Methods of the Estimation of h* Four independent methods to calculate the value of h* 2π(1.2×0.4)×10-22 Js.

  15. Neutral Buoyancy Simulator-NB32-Large Space Structure Assembly

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Once the United States' space program had progressed from Earth's orbit into outerspace, the prospect of building and maintaining a permanent presence in space was realized. To accomplish this feat, NASA launched a temporary workstation, Skylab, to discover the effects of low gravity and weightlessness on the human body, and also to develop tools and equipment that would be needed in the future to build and maintain a more permanent space station. The structures, techniques, and work schedules had to be carefully designed to fit this unique construction site. The components had to be lightweight for transport into orbit, yet durable. The station also had to be made with removable parts for easy servicing and repairs by astronauts. All of the tools necessary for service and repairs had to be designed for easy manipulation by a suited astronaut. Construction methods had to be efficient due to the limited time the astronauts could remain outside their controlled environment. In lieu of all the specific needs for this project, an environment on Earth had to be developed that could simulate a low gravity atmosphere. A Neutral Buoyancy Simulator (NBS) was constructed by NASA Marshall Space Flight Center (MSFC) in 1968. Since then, NASA scientists have used this facility to understand how humans work best in low gravity and also provide information about the different kinds of structures that can be built. As part of this experimentation, the Experimental Assembly of Structures in Extravehicular Activity (EASE) project was developed as a joint effort between MFSC and the Massachusetts Institute of Technology (MIT). The EASE experiment required that crew members assemble small components to form larger components, working from the payload bay of the space shuttle. Pictured is an entire unit that has been constructed and is sitting in the bottom of a mock-up shuttle cargo bay pallet.

  16. Large-size monodisperse latexes as a commercial space product

    NASA Technical Reports Server (NTRS)

    Kornfeld, D. M.

    1977-01-01

    Proposed spacelab production of large-size (2-40 micron diameter) monodispersed latexes is discussed. Explanations are given for the present lack of monodisperse particles in this size range. The four main topics discussed are: (1) the potential uses of these large particle size latexes, (2) why it is necessary for the particles to have a very narrow size distribution, (3) why large amounts of these monodisperse latexes are needed, and (4) why it is necessary to go to microgravity to prepare these latexes.

  17. Radiation-conduction interaction in large space structures

    NASA Technical Reports Server (NTRS)

    Emery, A. F.; Mortazavi, H. R.; Smith, S. O.

    1984-01-01

    The effects of a penumbra due to the long wave radiation emitted by the earth or to solar energy reflected from the earth on temperature distributions, deflections and stresses in plates are studied to determine their importance in the design of space structures. An examination of the state of stress in a thin plate exposed to the sun suggests that deflections are only slightly modified by the penumbra, but that stresses in the vicinity of the shadow line are more affected. Even with the smoothing due to the penumbra, these stresses should be considered in the design of space structures. A simple relationship is given by which albedo viewfactors can be easily derived from the direct viewfactor, thus simplifying the radiation analysis.

  18. Automated frequency domain system identification of a large space structure

    NASA Technical Reports Server (NTRS)

    Yam, Y.; Bayard, D. S.; Hadaegh, F. Y.; Mettler, E.; Milman, M. H.

    1989-01-01

    This paper presents the development and experimental results of an automated on-orbit system identification method for large flexible spacecraft that yields estimated quantities to support on-line design and tuning of robust high performance control systems. The procedure consists of applying an input to the plant, obtaining an output, and then conducting nonparametric identification to yield the spectral estimate of the system transfer function. A parametric model is determined by curve fitting the spectral estimate to a rational transfer function. The identification method has been demonstrated experimentally on the Large Spacecraft Control Laboratory in JPL.

  19. Evolution of the large Deep Space Network antennas

    NASA Astrophysics Data System (ADS)

    Imbriale, William A.

    1991-12-01

    The evolution of the largest antenna of the US NASA Deep Space Network (DSN) is described. The design, performance analysis, and measurement techniques, beginning with its initial 64-m operation at S-band (2295 MHz) in 1966 and continuing through the present ka-band (32-GHz) operation at 70 m, is described. Although their diameters and mountings differ, these parabolic antennas all employ a Cassegrainian feed system, and each antenna dish surface is constructed of precision-shaped perforated-aluminum panels that are secured to an open steel framework

  20. Tradespace investigation of strategic design factors for large space telescopes

    NASA Astrophysics Data System (ADS)

    Karlow, Brandon; Jewison, Christopher; Sternberg, David; Hall, Sherrie; Golkar, Alessandro

    2015-04-01

    Future large telescope arrays require careful balancing of satisfaction across the stakeholders' community. Development programs usually cannot afford to explicitly address all stakeholder tradeoffs during the conceptual design stage, but rather confine the analysis to performance, cost, and schedule discussions, treating policy and budget as constraints defining the envelope of the investigation. Thus, it is of interest to develop an integrated stakeholder analysis approach to explicitly address the impact of all stakeholder interactions on the design of large telescope arrays to address future science and exploration needs. This paper offers a quantitative approach for modeling some of the stakeholder influences relevant to large telescope array designs-the linkages between a given mission and the wider NASA community. The main goal of the analysis is to explore the tradespace of large telescope designs and understand the effects of different design decisions in the stakeholders' network. Proposed architectures that offer benefits to existing constellations of systems, institutions, and mission plans are expected to yield political and engineering benefits for NASA stakeholders' wider objectives. If such synergistic architectures are privileged in subsequent analysis, regions of the tradespace that better meet the needs of the wider NASA community can be selected for further development.

  1. Advanced technology requirements for large space structures. Part 5: Atlas program requirements

    NASA Technical Reports Server (NTRS)

    Katz, E.; Lillenas, A. N.; Broddy, J. A.

    1977-01-01

    The results of a special study which identifies and assigns priorities to technology requirements needed to accomplish a particular scenario of future large area space systems are described. Proposed future systems analyzed for technology requirements included large Electronic Mail, Microwave Radiometer, and Radar Surveillance Satellites. Twenty technology areas were identified as requirements to develop the proposed space systems.

  2. Validation of large space structures by ground tests

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Kuo, C. P.; Glaser, R. J.

    1986-01-01

    The paper presents concepts designed to validate, through the use of ground tests, mathematical models of continuous type structures and structures comprised of interconnecting subsystems. For continuous-type structures, a multiple boundary condition test approach is considered in which the basic idea is to perform a large number of tests using artificial boundary conditions from which good ground test data can be obtained. The test ensures an arbitrarily large number of test data for use in the validation and updating of the mathematical model. Another approach, applicable to structures comprised of subsystems, involves the identification of significant structural elements for the system dynamic model which are not validated by standard modal tests of the subsystems.

  3. Stabilization of large space structures by linear reluctance actuators

    NASA Technical Reports Server (NTRS)

    Biswas, Saroj K.; Sendaula, Henry M.

    1991-01-01

    Application of magnetic forces are considered for stabilization of vibrations of flexible space structures. Three electromagnetic phenomena are studied, such as: (1) magnetic body force; (2) reluctance torque; and (3) magnetostriction, and their application is analyzed for stabilization of a beam. The magnetic body force actuator uses the force that exists between poles of magnets. The reluctance actuator is configured in such a way that the reluctance of the magnetic circuit will be minimum when the beam is straight. Any bending of the beam increases the reluctance and hence generates a restoring torque that reduces bending. The gain of the actuator is controlled by varying the magnetizing current. Since the energy density of a magnetic device is much higher compared to piezoelectric or thermal actuators, it is expected that the reluctance actuator will be more effective in controlling the structural vibrations.

  4. Cables and connectors for Large Space System Technology (LSST)

    NASA Technical Reports Server (NTRS)

    Dunbar, W. G.

    1980-01-01

    The effect of the environment and extravehicular activity/remote assembly operations on the cables and connectors for spacecraft with metallic and/or nonmetallic structures was examined. Cable and connector philosophy was outlined for the electrical systems and electronic compartments which contain high-voltage, high-power electrical and electronic equipment. The influence of plasma and particulates on the system is analyzed and the effect of static buildup on the spacecraft electrical system discussed. Conceptual cable and connector designs are assessed for capability to withstand high current and high voltage without danger of arcs and electromagnetic interference. The extravehicular activites required of the space station and/or supply spacecraft crew members to join and inspect the electrical system, using manual or remote assembly construction are also considered.

  5. Dual structural-control optimization of large space structures

    NASA Technical Reports Server (NTRS)

    Messac, A.; Turner, J.

    1984-01-01

    A new approach is proposed for solving dual structural-control optimization problems for high-order flexible space structures where reduced-order structural models are employed. For a given initial structural dessign, a quadratic control cost is minimized subject to a constant-mass constraint. The sensitivity of the optimal control cost with respect to the stuctural design variables is then determined and used to obtain successive structural redesigns using a contrained gradient optimization algorithm. This process is repeated until the constrained control cost sensitivity becomes negligible. A numerical example is presented which demonstrates that this new approach effectively addresses the problem of dual optimization for potentially very high-order structures.

  6. Ground/bonding for Large Space System Technology (LSST)

    NASA Astrophysics Data System (ADS)

    Dunbar, W. G.

    1980-04-01

    The influence of the environment and extravehicular activity remote assembly operations on the grounding and bonding of metallic and nonmetallic structures is discussed. Grounding and bonding philosophy is outlined for the electrical systems and electronic compartments which contain high voltage, high power electrical and electronic equipment. The influence of plasma and particulate on the system was analyzed and the effects of static buildup on the spacecraft electrical system discussed. Conceptual grounding bonding designs are assessed for capability to withstand high current arcs to ground from a high voltage conductor and electromagnetic interference. Also shown were the extravehicular activities required of the space station and or supply spacecraft crew members to join and inspect the ground system using manual on remote assembly construction.

  7. Osmotic pumped heat pipes for large space platforms

    SciTech Connect

    Tanzer, H.J.; Fleischman, G.L.

    1982-01-01

    A thermal bus will be required as a thermal control source for future space platforms. The osmotic heat pipe is one candidate device with potential significant payoff toward serving growing thermal management needs. Results of a study evaluating osmotic heat pipes for thermal bus applications are presented. Electrostatic and other techniques are proposed for flow control and solution circulation in zero-gravity. Baseline size and performance design parameters of cellulose acetate membrane/sugar-water solution and other combinations were scaled up to predict osmotic pump performance for heat loads and temperatures of 4 to 120 C. A compact hollow-fiber membrane module measuring 20 inches in diameter by 12 inches long and weighing 190 pounds is projected for 50-kW heat loads.

  8. Economics of ion propulsion for large space systems

    NASA Technical Reports Server (NTRS)

    Masek, T. D.; Ward, J. W.; Rawlin, V. K.

    1978-01-01

    This study of advanced electrostatic ion thrusters for space propulsion was initiated to determine the suitability of the baseline 30-cm thruster for future missions and to identify other thruster concepts that would better satisfy mission requirements. The general scope of the study was to review mission requirements, select thruster designs to meet these requirements, assess the associated thruster technology requirements, and recommend short- and long-term technology directions that would support future thruster needs. Preliminary design concepts for several advanced thrusters were developed to assess the potential practical difficulties of a new design. This study produced useful general methodologies for assessing both planetary and earth orbit missions. For planetary missions, the assessment is in terms of payload performance as a function of propulsion system technology level. For earth orbit missions, the assessment is made on the basis of cost (cost sensitivity to propulsion system technology level).

  9. Recent developments in thermal analysis of large space structures

    NASA Technical Reports Server (NTRS)

    Oneill, R. F.

    1983-01-01

    A numerical procedure for analysis of shadowed space heating of sparse structures, SSQ, is discussed. The SSQ program avoids inordinate computational complexity by confining attention to a single elemental location on a structural member of interest throughout an entire orbital period, proceeding then to similar treatment of individual alternate locations. The procedure considers a spacecraft in circular orbit and assumes fixed-Earth orientation of the spacecraft. Shadow orientation and interval duration, merged shadows, and computation of solar heat flux and thermal response are addressed. The output options of the SSQ FORTRAN 5 program and its efficiency are discussed. Application of the system to the analysis of a parabolic expandable truss antenna is considered.

  10. Controls for orbital assembly of large space structures

    NASA Technical Reports Server (NTRS)

    Balas, Mark J.; Davidson, Roger; Gooyabadi, Ali A.; Quan, Ralph; Reisenauer, Brian; Robertson, L.; Mohl, James; Good, Philip; Vredevoogd, Loren; Galvez, Jose

    1991-01-01

    The topics covered are presented in viewgraph form and include the following: flexible structure control; decentralized control for flexible multi-body systems; control of structures during assembly; decentralized control using structural partitioning; reduced-orded model-based controller design; ROM/residual mode filters (RMF) control of large flexible structures;RMF in a distributed parameter system (DPS); LSS active control simulation; 3-D truss beam; mobile transporter with RMS; and flexible robot manipulator.

  11. Dynamic Identification for Control of Large Space Structures

    NASA Technical Reports Server (NTRS)

    Ibrahim, S. R.

    1985-01-01

    This is a compilation of reports by the one author on one subject. It consists of the following five journal articles: (1) A Parametric Study of the Ibrahim Time Domain Modal Identification Algorithm; (2) Large Modal Survey Testing Using the Ibrahim Time Domain Identification Technique; (3) Computation of Normal Modes from Identified Complex Modes; (4) Dynamic Modeling of Structural from Measured Complex Modes; and (5) Time Domain Quasi-Linear Identification of Nonlinear Dynamic Systems.

  12. Space transportation booster engine thrust chamber technology, large scale injector

    NASA Technical Reports Server (NTRS)

    Schneider, J. A.

    1993-01-01

    The objective of the Large Scale Injector (LSI) program was to deliver a 21 inch diameter, 600,000 lbf thrust class injector to NASA/MSFC for hot fire testing. The hot fire test program would demonstrate the feasibility and integrity of the full scale injector, including combustion stability, chamber wall compatibility (thermal management), and injector performance. The 21 inch diameter injector was delivered in September of 1991.

  13. The dynamics and control of large flexible space structures

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Krishna, R.; Kumar, V. K.; Reddy, A. S. S. R.

    1981-01-01

    The dynamics and attitude and shape control of very large, inherently flexible spacecraft systems were investigated. Increasingly more complex examples were examined, beginning with a uniform free-free beam, next a free-free uniform plate/platform and finally by considering a thin shallow spherical shell structure in orbit. The effects devices were modeled. For given sets of assumed actuator locations, the controllability of these systems was first established. Control laws for each of the actuators were developed based on decoupling techniques (including distributed modal control) pole placement algorithms and a application of the linear regulator problem for optical control theory.

  14. Pushbroom radiometry and its potential using large space antennas

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Keafer, L. S., Jr.

    1983-01-01

    Electromagnetic radiation is emitted by matter which was heated to a temperature above absolute zero. The amount of blackbody radiation in the microwave frequency region of interest (10 to the 8th power f 10 to the 10th power Hz) emitted by matter can be determined from the Rayleigh-Jeans approximation to Planck's Radiation Law. The amount of electromagnetic radiation from matter which is not a blackbody is a function of the emissivity of the material. The emissivity is a factor less than unity and is a function of several parameters including chemical composition, temperature, frequency, surface characteristics, and viewing angle. A radiometer is an instrument which detects and provides a measure of the electromagnetic radiation being emitted by a material or surface area within the radiometer's antenna beamwidth. Microwave radiometers provide the capability for remote measurements from Earth orbits of geophysical parameters. These measurements will require the use of a microwave imaging radiometer using a large aperture deployable antenna with multiple beams in a pushbroom mode to achieve high spatial resolution and large swath width.

  15. The dynamics and control of large flexible space structures - 13

    NASA Technical Reports Server (NTRS)

    Bainum, Peter M.; Li, Feiyue; Xu, Jianke

    1990-01-01

    The optimal control of three-dimensional large angle maneuvers and vibrations of a Shuttle-mast-reflector system is considered. The nonlinear equations of motion are formulated by using Lagrange's formula, with the mast modeled as a continuous beam subject to three-dimensional deformations. Pontryagin's Maximum Principle is applied to the slewing problem, to derive the necessary conditions for the optimal controls, which are bounded by given saturation levels. The resulting two point boundary value problem is then solved by using the quasilinearization algorithm and the method of particular solutions. The study of the large angle maneuvering of the Shuttle-beam-reflector spacecraft in the plane of a circular earth orbit is extended to consider the effects of the structural offset connection, the axial shortening, and the gravitational torque on the slewing motion. Finally the effect of additional design parameters (such as related to additional payload requirement) on the linear quadratic regulator based design of an orbiting control/structural system is examined.

  16. Fermi: The Gamma-Ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2014-01-01

    Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

  17. Integrated structural control design of large space structures

    SciTech Connect

    Allen, J.J.; Lauffer, J.P.

    1995-01-01

    Active control of structures has been under intensive development for the last ten years. Reference 2 reviews much of the identification and control technology for structural control developed during this time. The technology was initially focused on space structure and weapon applications; however, recently the technology is also being directed toward applications in manufacturing and transportation. Much of this technology focused on multiple-input/multiple-output (MIMO) identification and control methodology because many of the applications require a coordinated control involving multiple disturbances and control objectives where multiple actuators and sensors are necessary for high performance. There have been many optimal robust control methods developed for the design of MIMO robust control laws; however, there appears to be a significant gap between the theoretical development and experimental evaluation of control and identification methods to address structural control applications. Many methods have been developed for MIMO identification and control of structures, such as the Eigensystem Realization Algorithm (ERA), Q-Markov Covariance Equivalent Realization (Q-Markov COVER) for identification; and, Linear Quadratic Gaussian (LQG), Frequency Weighted LQG and H-/ii-synthesis methods for control. Upon implementation, many of the identification and control methods have shown limitations such as the excitation of unmodelled dynamics and sensitivity to system parameter variations. As a result, research on methods which address these problems have been conducted.

  18. Formation Flying of Components of a Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Mettler, Edward; Quadrelli, Marco; Breckenridge, William

    2009-01-01

    A conceptual space telescope having an aperture tens of meters wide and a focal length of hundreds of meters would be implemented as a group of six separate optical modules flying in formation: a primary-membrane-mirror module, a relay-mirror module, a focal-plane-assembly module containing a fast steering mirror and secondary and tertiary optics, a primary-mirror-figure-sensing module, a scanning-electron-beam module for controlling the shape of the primary mirror, and a sunshade module. Formation flying would make it unnecessary to maintain the required precise alignments among the modules by means of an impractically massive rigid structure. Instead, a control system operating in conjunction with a metrology system comprising optical and radio subsystems would control the firing of small thrusters on the separate modules to maintain the formation, thereby acting as a virtual rigid structure. The control system would utilize a combination of centralized- and decentralized-control methods according to a leader-follower approach. The feasibility of the concept was demonstrated in computational simulations that showed that relative positions could be maintained to within a fraction of a millimeter and orientations to within several microradians.

  19. Large Energy Development Projects: Lessons Learned from Space and Politics

    SciTech Connect

    Schmitt, Harrison H.

    2005-04-15

    The challenge to global energy future lies in meeting the needs and aspirations of the ten to twelve billion earthlings that will be on this planet by 2050. At least an eight-fold increase in annual production will be required by the middle of this century. The energy sources that can be considered developed and 'in the box' for consideration as sources for major increases in supply over the next half century are fossil fuels, nuclear fission, and, to a lesser degree, various forms of direct and stored solar energy and conservation. None of these near-term sources of energy will provide an eight-fold or more increase in energy supply for various technical, environmental and political reasons.Only a few potential energy sources that fall 'out of the box' appear worthy of additional consideration as possible contributors to energy demand in 2050 and beyond. These particular candidates are deuterium-tritium fusion, space solar energy, and lunar helium-3 fusion. The primary advantage that lunar helium-3 fusion will have over other 'out of the box' energy sources in the pre-2050 timeframe is a clear path into the private capital markets. The development and demonstration of new energy sources will require several development paths, each of Apollo-like complexity and each with sub-paths of parallel development for critical functions and components.

  20. Large craters on the meteoroid and space debris impact experiment

    NASA Technical Reports Server (NTRS)

    Humes, Donald H.

    1992-01-01

    Examination of 29.37 sq m of thick aluminum plates from the LDEF, which were exposed to the meteoroid and man-made orbital debris environments for 5.8 years, revealed 606 craters that were 0.5 mm in diameter or larger. Most were nearly hemispherical. There was a large variation in the number density of craters around the three axis gravity gradient stabilized spacecraft. A new model of the near-Earth meteoroid environment gives good agreement with the crater fluxes measured on the fourteen faces of the LDEF. The man-made orbital debris model of Kessler, which predicts that 16 pct. of the craters would be caused by man-made debris, is plausible. No chemical analyses of impactor residue that will distinguish between meteoroids and man-made debris is yet available.

  1. Mass Efficiencies for Common Large-Scale Precision Space Structures

    NASA Technical Reports Server (NTRS)

    Williams, R. Brett; Agnes, Gregory S.

    2005-01-01

    This paper presents a mass-based trade study for large-scale deployable triangular trusses, where the longerons can be monocoque tubes, isogrid tubes, or coilable longeron trusses. Such structures are typically used to support heavy reflectors, solar panels, or other instruments, and are subject to thermal gradients that can vary a great deal based on orbital altitude, location in orbit, and self-shadowing. While multi layer insulation (MLI) blankets are commonly used to minimize the magnitude of these thermal disturbances, they subject the truss to a nonstructural mass penalty. This paper investigates the impact of these add-on thermal protection layers on selecting the lightest precision structure for a given loading scenario.

  2. Systems identification technology development for large space systems

    NASA Technical Reports Server (NTRS)

    Armstrong, E. S.

    1982-01-01

    A methodology for synthesizinng systems identification, both parameter and state, estimation and related control schemes for flexible aerospace structures is developed with emphasis on the Maypole hoop column antenna as a real world application. Modeling studies of the Maypole cable hoop membrane type antenna are conducted using a transfer matrix numerical analysis approach. This methodology was chosen as particularly well suited for handling a large number of antenna configurations of a generic type. A dedicated transfer matrix analysis, both by virtue of its specialization and the inherently easy compartmentalization of the formulation and numerical procedures, is significantly more efficient not only in computer time required but, more importantly, in the time needed to review and interpret the results.

  3. Testing gravity using large-scale redshift-space distortions

    NASA Astrophysics Data System (ADS)

    Raccanelli, Alvise; Bertacca, Daniele; Pietrobon, Davide; Schmidt, Fabian; Samushia, Lado; Bartolo, Nicola; Doré, Olivier; Matarrese, Sabino; Percival, Will J.

    2013-11-01

    We use luminous red galaxies from the Sloan Digital Sky Survey (SDSS) II to test the cosmological structure growth in two alternatives to the standard Λ cold dark matter (ΛCDM)+general relativity (GR) cosmological model. We compare observed three-dimensional clustering in SDSS Data Release 7 (DR7) with theoretical predictions for the standard vanilla ΛCDM+GR model, unified dark matter (UDM) cosmologies and the normal branch Dvali-Gabadadze-Porrati (nDGP). In computing the expected correlations in UDM cosmologies, we derive a parametrized formula for the growth factor in these models. For our analysis we apply the methodology tested in Raccanelli et al. and use the measurements of Samushia et al. that account for survey geometry, non-linear and wide-angle effects and the distribution of pair orientation. We show that the estimate of the growth rate is potentially degenerate with wide-angle effects, meaning that extremely accurate measurements of the growth rate on large scales will need to take such effects into account. We use measurements of the zeroth and second-order moments of the correlation function from SDSS DR7 data and the Large Suite of Dark Matter Simulations (LasDamas), and perform a likelihood analysis to constrain the parameters of the models. Using information on the clustering up to rmax = 120 h-1 Mpc, and after marginalizing over the bias, we find, for UDM models, a speed of sound c∞ ≤ 6.1e-4, and, for the nDGP model, a cross-over scale rc ≥ 340 Mpc, at 95 per cent confidence level.

  4. Development of a large area space solar cell assembly

    NASA Technical Reports Server (NTRS)

    Spitzer, M. B.

    1982-01-01

    The development of a large area high efficiency solar cell assembly is described. The assembly consists of an ion implanted silicon solar cell and glass cover. The important attributes of fabrication are the use of a back surface field which is compatible with a back surface reflector, and integration of coverglass application and cell fabrications. Cell development experiments concerned optimization of ion implantation processing of 2 ohm-cm boron-doped silicon. Process parameters were selected based on these experiments and cells with area of 34.3 sq cm wre fabricated. The average AMO efficiency of the twenty-five best cells was 13.9% and the best bell had an efficiency of 14.4%. An important innovation in cell encapsulation was also developed. In this technique, the coverglass is applied before the cell is sawed to final size. The coverglass and cell are then sawed as a unit. In this way, the cost of the coverglass is reduced, since the tolerance on glass size is relaxed, and costly coverglass/cell alignment procedures are eliminated. Adhesive investigated were EVA, FEP-Teflon sheet and DC 93-500. Details of processing and results are reported.

  5. Space-plasma campaign on UCLA's Large Plasma Device (LAPD)

    NASA Astrophysics Data System (ADS)

    Koepke, M. E.; Finnegan, S. M.; Knudsen, D. J.; Vincena, S.

    2007-05-01

    Knudsen [JGR, 1996] describes a potential role for stationary Alfvén (StA) waves in auroral arcs' frequency dependence. Magnetized plasmas are predicted to support electromagnetic perturbations that are static in a fixed frame if there is uniform background plasma convection. These stationary waves should not be confused with standing waves that oscillate in time with a fixed, spatially varying envelope. Stationary waves have no time variation in the fixed frame. In the drifting frame, there is an apparent time dependence as plasma convects past fixed electromagnetic structures. We describe early results from an experimental campaign to reproduce in the lab the basic conditions necessary for the creation of StA waves, namely quasi-steady-state convection across magnetic field-aligned current channels. We show that an off-axis, fixed channel of electron current (and depleted density) is created in the Large Plasma Device Upgrade (LAPD) at UCLA, using a small, heated, oxide-coated electrode at one plasma-column end and we show that the larger plasma column rotates about its cylindrical axis from a radial electric field imposed by a special termination electrode on the same end. Initial experimentation with plasma-rotation-inducing termination electrodes began in May 2006 in the West Virginia Q Machine, leading to two designs that, in January 2007, were tested in LAPD. The radial profile of azimuthal velocity was consistent with predictions of rigid-body rotation. Current-channel experiments in LAPD, in August 2006, showed that inertial Alfvén waves could be concentrated in an off-axis channel of electron current and depleted plasma density. These experimental results will be presented and discussed. This research is supported by DOE and NSF.

  6. Innovative research in the design and operation of large telescopes for space: Aspects of giant telescopes in space

    NASA Technical Reports Server (NTRS)

    Angel, J. R. P.

    1985-01-01

    The capability and understanding of how to finish the reflector surfaces needed for large space telescopes is discussed. The technology for making very light glass substrates for mirrors is described. Other areas of development are in wide field imaging design for very fast primaries, in data analysis and retrieval methods for astronomical images, and in methods for making large area closely packed mosaics of solid state array detectors.

  7. Extraterrestrial processing and manufacturing of large space systems. Volume 3: Executive summary

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Smith, D. B. S.

    1979-01-01

    Facilities and equipment are defined for refining processes to commercial grade of lunar material that is delivered to a 'space manufacturing facility' in beneficiated, primary processed quality. The manufacturing facilities and the equipment for producing elements of large space systems from these materials and providing programmatic assessments of the concepts are also defined. In-space production processes of solar cells (by vapor deposition) and arrays, structures and joints, conduits, waveguides, RF equipment radiators, wire cables, converters, and others are described.

  8. Extraterrestrial processing and manufacturing of large space systems, volume 1, chapters 1-6

    NASA Technical Reports Server (NTRS)

    Miller, R. H.; Smith, D. B. S.

    1979-01-01

    Space program scenarios for production of large space structures from lunar materials are defined. The concept of the space manufacturing facility (SMF) is presented. The manufacturing processes and equipment for the SMF are defined and the conceptual layouts are described for the production of solar cells and arrays, structures and joints, conduits, waveguides, RF equipment radiators, wire cables, and converters. A 'reference' SMF was designed and its operation requirements are described.

  9. Development of precision structure of a large-size space radio telescope

    NASA Astrophysics Data System (ADS)

    Astavin, A. S.; Kovalev, V. S.; Komaev, R. V.; Moisheev, A. A.; Tsvelev, V. M.; Serebrennikov, V. A.

    2015-12-01

    The paper presents methods for the design and engineering concepts, which made it possible to develop and manufacture the space radio telescope with a large size and high accuracy of the effective reflector area and focal assembly position.

  10. Some interdisciplinary trade-offs in the design of large space structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1982-01-01

    The constraints placed on the design of large space structures by acceleration, attitude control, and stationkeeping forces are discussed. Stiffness requirements for the structures are derived. The use of active versus passive accuracy control methods is also addressed.

  11. 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.

  12. Systems definition study for shuttle demonstration flights of large space structures. Volume 3: Thermal analyses

    NASA Technical Reports Server (NTRS)

    1979-01-01

    the development of large space structure technology is discussed. A detailed thermal analysis of a model space fabricated 1 meter beam is presented. Alternative thermal coatings are evaluated, and deflections, stresses, and stiffness variations resulting from flight orientations and solar conditions are predicted.

  13. 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.

  14. Development of space stable thermal control coatings for use on large space vehicles. [metal coatings

    NASA Technical Reports Server (NTRS)

    Gilligan, J. E.; Harada, Y.

    1974-01-01

    The development of a large scale manufacturing method for the production of a stable zinc orthotitanate pigment by means of an oxalate co-precipitation method is examined. Pigments were prepared at various temperatures, and major emphasis was placed on the determination of the important parameters of post-precipitation firing and treatment. A large-scale process for the modification of a glass resin binder was developed and paints were formulated using the binder.

  15. Definition of ground test for verification of large space structure control

    NASA Technical Reports Server (NTRS)

    Doane, G. B., III; Glaese, J. R.; Tollison, D. K.; Howsman, T. G.; Curtis, S. (Editor); Banks, B.

    1984-01-01

    Control theory and design, dynamic system modelling, and simulation of test scenarios are the main ideas discussed. The overall effort is the achievement at Marshall Space Flight Center of a successful ground test experiment of a large space structure. A simplified planar model of ground test experiment of a large space structure. A simplified planar model of ground test verification was developed. The elimination from that model of the uncontrollable rigid body modes was also examined. Also studied was the hardware/software of computation speed.

  16. Relating Berkovits and A ∞ superstring field theories; large Hilbert space perspective

    NASA Astrophysics Data System (ADS)

    Erler, Theodore

    2016-02-01

    We lift the dynamical field of the A ∞ superstring field theory to the large Hilbert space by introducing a gauge invariance associated with the eta zero mode. We then provide a field redefinition which relates the lifted field to the dynamical field of Berkovits' superstring field theory in the large Hilbert space. This generalizes the field redefinition in the small Hilbert space described in earlier works, and gives some understanding of the relation between the gauge symmetries of the theories. It also provides a new perspective on the algebraic structure underlying gauge invariance of the Wess-Zumino-Witten-like action.

  17. Development of space stable thermal control coatings for use on large space vehicles

    NASA Technical Reports Server (NTRS)

    Gilligan, J. E.; Harada, Y.

    1975-01-01

    The development of a large scale manufacturing method for the production of a stable zinc orthotitanate pigment is studied, with emphasis placed on the comprehensive analysis of the properties and environmental stability of oxalate precursor zinc orthotitanate pigments and of the preparative conditions (time and temperature) leading to optimum properties and optical stability.

  18. 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.

  19. The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers and Technology Developments

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

    2011-01-01

    The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers and the resulting performance requirements for ATLAST (8 to 16 milliarcsecond angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to current generation observatory-class space missions. Keywords: Advanced Technology Large-Aperture Space Telescope (ATLAST); ultraviolet/optical space telescopes; astrophysics; astrobiology; technology development.

  20. The control and estimation of large space structures. [for optimal shape variation with respect to space and time

    NASA Technical Reports Server (NTRS)

    Weeks, C.

    1980-01-01

    A shape control or estimation problem for a large space structure can be modeled by a partial differential equation which represents changes in shape with respect to space and time, together with spatially discrete forcing functions or observations which represent the placement of actuators or sensors at discrete points along the structure. The use of Green's functions to convert boundary value problems into integral equations provides a convenient treatment of this mixture of continuous and discrete mathematics. Control and estimation algorithms are developed for the one-dimensional static beam to illustrate this technique.

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

    SciTech Connect

    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 threshold 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

  2. Interpretation of plasma diagnostics package results in terms of large space structure plasma interactions

    NASA Technical Reports Server (NTRS)

    Kurth, William S.

    1991-01-01

    The Plasma Diagnostics Package (PDP) is a spacecraft which was designed and built at The University of Iowa and which contained several scientific instruments. These instruments were used for measuring Space Shuttle Orbiter environmental parameters and plasma parameters. The PDP flew on two Space Shuttle flights. The first flight of the PDP was on Space Shuttle Mission STS-3 and was a part of the NASA/Office of Space Science payload (OSS-1). The second flight of the PDP was on Space Shuttle Mission STS/51F and was a part of Spacelab 2. The interpretation of both the OSS-1 and Spacelab 2 PDP results in terms of large space structure plasma interactions is emphasized.

  3. Which future for electromagnetic Astronomy: Ground Based vs Space Borne Large Astrophysical Facilities

    NASA Astrophysics Data System (ADS)

    Ubertini, Pietro

    2015-08-01

    The combined use of large ground based facilities and large space observatories is playing a key role in the advance of astrophysics by providing access to the entire electromagnetic spectrum, allowing high sensitivity observations from the lower radio wavelength to the higher energy gamma rays.It is nowadays clear that a forward steps in the understanding of the Universe evolution and large scale structure formation is essential and only possible with the combined use of multiwavelength imaging and spectral high resolution instruments.The increasing size, complexity and cost of large ground and space observatories places a growing emphasis on international collaboration. If the present set of astronomical facilities is impressive and complete, with nicely complementary space and ground based telescopes, the scenario becomes worrisome and critical in the next two decades. In fact, only a few ‘Large’ main space missions are planned and there is a need to ensure proper ground facility coverage: the synergy Ground-Space is not escapable in the timeframe 2020-2030.The scope of this talk is to review the current astronomical instrumentation panorama also in view of the recent major national agencies and international bodies programmatic decisions.This Division B meeting give us a unique opportunity to review the current situation and discuss the future perspectives taking advantage of the large audience ensured by the IAU GA.

  4. Magnetic control systems for large spacecraft with applications to space telescope

    NASA Technical Reports Server (NTRS)

    Dougherty, H.; Machnick, J.; Nakashima, A.; Henry, J.; Tompetrini, K.

    1981-01-01

    Magnetic control systems for large space vehicles offer the advantage of a simple, reliable, low cost augmentation to the primary control system. When used for momentum management, a magnetic torque source offers a long life and noncontaminant environment when compared to a mass expulsion torque source. These qualities make such systems suitable for employment with the Space Telescope, which is a long life, high performance vehicle with optics and scientific instruments which would be degraded by contamination due to mass expulsion products. The various applications of magnetic systems on the Space Telescope are considered. The future trend in magnetic control of large space vehicles lies in providing a known three axis reference for backup operations, such as recovery of the primary control mode.

  5. Analysis of large space structures assembly: Man/machine assembly analysis

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Procedures for analyzing large space structures assembly via three primary modes: manual, remote and automated are outlined. Data bases on each of the assembly modes and a general data base on the shuttle capabilities to support structures assembly are presented. Task element times and structure assembly component costs are given to provide a basis for determining the comparative economics of assembly alternatives. The lessons learned from simulations of space structures assembly are detailed.

  6. Design and fabrication of a large primary reflector structure for space laser power beaming

    SciTech Connect

    MacNeal, P.; Jewett, K.

    1994-12-31

    This paper discusses the design issues and fabrication considerations specifically related to a large twelve meter, graphite-epoxy space truss that has been developed to provide support of the primary mirror system for the SpacE Laser ENErgy (SELENE) Beam Transmission Optical System (BTOS). Details of the optical system and wavefront corrector concepts have been discussed in prior papers. Specific issues which are addressed in this paper include optical performance needs, environmental requirements, and low-cost fabrication techniques.

  7. Computer-aided design and distributed system technology development for large space structures

    NASA Technical Reports Server (NTRS)

    Armstrong, Ernest S.; Joshi, Suresh M.

    1986-01-01

    Proposed large space structures have many characteristics that make them difficult to analyze and control. They are highly flexible, with components mathematically modeled by partial differential equations or very large systems of ordinary differential equations. They have many resonant frequencies, typically low and closely spaced. Natural damping may be low and/or improperly modeled. Coupled with stringent operational requirements of orientation, shape control, and vibration suppression, and the inability to perform adequate ground testing, these characteristics present an unconventional identification and control design problem to the systems theorist. Some of the research underway within Langley's Spacecraft Control Branch, Guidance and Control Division aimed at developing theory and algorithms to treat large space structures systems identification and control problems is described. The research areas to be considered are computer-aided design algorithms, and systems identification and control of distributed systems.

  8. In-situ optical measurement of separation angles between bifacial lines in large scale space

    NASA Astrophysics Data System (ADS)

    Zhang, H. W.; Zhang, G. X.; Qiu, Z. R.; Hu, W. C.; Liu, M.

    2010-08-01

    An optical method is proposed for in-situ measurement of angles of space elements separated at a distance of several or several tens of meters. When it is necessary to measure large objects or geometrical elements within a large scale space, it is not always possible to bring these workpieces to conventional coordinate measuring machines (CMMs) which are widely used in industries. Mobile measuring systems provide ideal solutions for these applications. The basic idea of the presented research work is to set up the multiple common optical references through which the dimensional inspections of separation angles of bifacial lines in a large scale space can be fulfilled. The angles between the projection light and each element can be captured through a machine vision system, and thereafter the angles between those corresponding elements can be determined using the geometrical principles. The method and the calibration approach have been validated on our designed work station.

  9. Technology needs and opportunities for future NASA missions. [large space structures and related systems

    NASA Technical Reports Server (NTRS)

    Sadin, S. R.

    1978-01-01

    The process of forecasting NASA's future needs and missions as well as the technologies relevant to the projected requirements is examined with emphasis on large space system technology. A technology model (set of generic systems) is presented to assist in the development of technology program options, to identify major technology areas requiring concentrated effort, and to serve as an evaluation criteria for current technology programs. The model is applied to considerations of near and far term opportunities for exploration of the universe, global services, utilization of the space environment, and the space transportation system.

  10. Overview and Recent Accomplishments of Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2013-01-01

    AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

  11. The silicon-strip tracker of the Gamma ray Large Area Space Telescope

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Angelini, F.; Bagagli, R.; Baldini, L.; Brez, A.; Ceccanti, M.; Cohen Tanugi, J.; Kuss, M.; Latronico, L.; Massai, M. M.; Minuti, M.; Omodei, N.; Spandre, G.; Vigiani, L.; Zetti, F.

    2003-10-01

    The Gamma ray Large Area Space Telescope (GLAST) is an astro-particle mission that will study the mostly unexplored, high energy (20MeV-1TeV) spectrum of photons coming from active sources in the universe. Construction of the GLAST silicon tracker, by far the largest ever built for a space mission, is now well on the way, as it is scheduled for launch by NASA in autumn 2006. We report on the basic technology adopted for the silicon detectors, particularly in connection to their use in space, on the first results of sensors testing and on the status of tracker assembly.

  12. Navigation in large information spaces represented as hypertext: A review of the literature

    NASA Technical Reports Server (NTRS)

    Brown, Marcus

    1990-01-01

    The problem addressed is the failure of information-space navigation tools when the space grows to large. The basic goal is to provide the power of the hypertext interface in such a way as to be most easily comprehensible to the user. It was determined that the optimal structure for information is an overlapping, simplified hierarchy. The hierarchical structure should be made obvious to the user, and many of the non-hierarchical links in the information space should either by eliminated, or should be de-emphasized so that the novice user is not confused by them. Only one of the hierarchies should be very simple.

  13. On the apparent insignificance of the randomness of flexible joints on large space truss dynamics

    NASA Technical Reports Server (NTRS)

    Koch, R. M.; Klosner, J. M.

    1993-01-01

    Deployable periodic large space structures have been shown to exhibit high dynamic sensitivity to period-breaking imperfections and uncertainties. These can be brought on by manufacturing or assembly errors, structural imperfections, as well as nonlinear and/or nonconservative joint behavior. In addition, the necessity of precise pointing and position capability can require the consideration of these usually negligible and unknown parametric uncertainties and their effect on the overall dynamic response of large space structures. This work describes the use of a new design approach for the global dynamic solution of beam-like periodic space structures possessing parametric uncertainties. Specifically, the effect of random flexible joints on the free vibrations of simply-supported periodic large space trusses is considered. The formulation is a hybrid approach in terms of an extended Timoshenko beam continuum model, Monte Carlo simulation scheme, and first-order perturbation methods. The mean and mean-square response statistics for a variety of free random vibration problems are derived for various input random joint stiffness probability distributions. The results of this effort show that, although joint flexibility has a substantial effect on the modal dynamic response of periodic large space trusses, the effect of any reasonable uncertainty or randomness associated with these joint flexibilities is insignificant.

  14. Interactive computer graphics and its role in control system design of large space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.

    1985-01-01

    This paper attempts to show the relevance of interactive computer graphics in the design of control systems to maintain attitude and shape of large space structures to accomplish the required mission objectives. The typical phases of control system design, starting from the physical model such as modeling the dynamics, modal analysis, and control system design methodology are reviewed and the need of the interactive computer graphics is demonstrated. Typical constituent parts of large space structures such as free-free beams and free-free plates are used to demonstrate the complexity of the control system design and the effectiveness of the interactive computer graphics.

  15. Dispersion, damping and confinement of propagating pulses in large space structures

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1988-01-01

    Pulse propagations in large space structures caused by repeated pulse excitations are studied analytically (by using the Z-transforms) and numerically. It is found that resonance regimes can be generated not only by periodical, but also by non-periodical repeated pulses; the conditions for such regimes are derived. Special attention is paid to the dispersion of propagating pulses due to structural irregularities, to damping of pulses due to appropriate combination of elastic and viscous properties of joints between structural members, and to the protection of certain areas of Large Space Structures (LSS) from impacts provided by a pulse trapping effect.

  16. A travelling wave approach to the dynamic analysis of large space structures

    NASA Technical Reports Server (NTRS)

    Von Flotow, A. H.

    1983-01-01

    This paper investigates the dynamic analysis of certain large space structures via travelling wave mathematics. It is assumed that large space structures may be modelled as networks of interconnected one-dimensional structural members. Bodies with a finite number of internal dynamic degrees of freedom may be scattered throughout the network. The wave propagation behavior of one-dimensional continuous and periodic structural elements is investigated. A scattering matrix description of junctions and discontinuities is proposed. A time domain method of calculating network transient response using the wave propagation characteristics of the elements is briefly described.

  17. On the accuracy of modelling the dynamics of large space structures

    NASA Technical Reports Server (NTRS)

    Diarra, C. M.; Bainum, P. M.

    1985-01-01

    Proposed space missions will require large scale, light weight, space based structural systems. Large space structure technology (LSST) systems will have to accommodate (among others): ocean data systems; electronic mail systems; large multibeam antenna systems; and, space based solar power systems. The structures are to be delivered into orbit by the space shuttle. Because of their inherent size, modelling techniques and scaling algorithms must be developed so that system performance can be predicted accurately prior to launch and assembly. When the size and weight-to-area ratio of proposed LSST systems dictate that the entire system be considered flexible, there are two basic modeling methods which can be used. The first is a continuum approach, a mathematical formulation for predicting the motion of a general orbiting flexible body, in which elastic deformations are considered small compared with characteristic body dimensions. This approach is based on an a priori knowledge of the frequencies and shape functions of all modes included within the system model. Alternatively, finite element techniques can be used to model the entire structure as a system of lumped masses connected by a series of (restoring) springs and possibly dampers. In addition, a computational algorithm was developed to evaluate the coefficients of the various coupling terms in the equations of motion as applied to the finite element model of the Hoop/Column.

  18. On the accuracy of modelling the dynamics of large space structures

    NASA Technical Reports Server (NTRS)

    Diarra, C. M.; Bainum, P. M.

    1985-01-01

    Proposed space missions will require large scale, light weight, space based structural systems. Large space structure technology (LSST) systems will have to accommodate (among others): ocean data systems; electronic mail systems; large multibeam antenna systems; and, space based solar power systems. The structures are to be delivered into orbit by the Space Shuttle. Because of their inherent size, modelling techniques and scaling algorithms must be developed so that system performance can be predicted accurately prior to launch and assembly. When the size and weight-to-area ratio of proposed LSST systems dictate that the entire system be considered flexible, there are two basic modelling methods which can be used. The first is a continuum approach, a mathematical formulation for predicting the motion of a general orbiting flexible body, in which elastic deformations are considered small compared with characteristic body dimensions. This approach is based on an a priori knowledge of the frequencies and shape functions of all modes included within the system model. Alternatively, finite element techniques can be used to model the entire structure as a system of lumped masses connected by a series of (restoring) springs and possibly dampers. In addition, a computational algorithm was developed to evaluate the coefficients of the various coupling terms in the equations of motion as applied to the finite element model of the Hoop/Column.

  19. Development of Large-Aperture, Light-Weight Fresnel Lenses for Gossamer Space Telescopes

    SciTech Connect

    Sham, D; Hyde, R; Weisberg, A; Early, J; Rushford, M; Britten, J

    2002-04-29

    In order to examine more distant astronomical objects, with higher resolution, future space telescopes require objectives with significantly larger aperture than presently available. NASA has identified a progression in size from the 2.4m aperture objective currently used in the HUBBLE space telescope[l,2], to 25m and greater in order to observe, e.g., extra-solar planets. Since weight is a crucial factor for any object sent into space, the relative weight of large optics over a given area must be reduced[3]. The areal mass density of the primary mirror for the Hubble space telescope is {approx}200 kg/m{sup 2}. This is expected to be reduced to around 15 kg/m{sup 2} for the successor to Hubble--the next generation space telescope (NGST)[4]. For future very large aperture telescopes needed for extra-solar planet detection, the areal mass density must be reduced even further. For example, the areal mass density goal for the Gossamer space telescopes is < 1 kg/m{sup 2}. The production of lightweight focusing optics at >10m size is also an enabling technology for many other applications such as Earth observation, power beaming, and optical communications.

  20. Laboratory Spectroscopy of Large Carbon Molecules and Ions in Support of Space Missions. A New Generation of Laboratory & Space Studies

    NASA Technical Reports Server (NTRS)

    Salama, Farid; Tan, Xiaofeng; Cami, Jan; Biennier, Ludovic; Remy, Jerome

    2006-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. A long-standing and major challenge for laboratory astrophysics has been to measure the spectra of large carbon molecules in laboratory environments that mimic (in a realistic way) the physical conditions that are associated with the interstellar emission and absorption regions [1]. This objective has been identified as one of the critical Laboratory Astrophysics objectives to optimize the data return from space missions [2]. An extensive laboratory program has been developed to assess the properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space. We present and discuss the gas-phase electronic absorption spectra of neutral and ionized PAHs measured in the UV-Visible-NIR range in astrophysically relevant environments and discuss the implications for astrophysics [1]. The harsh physical conditions of the interstellar medium characterized by a low temperature, an absence of collisions and strong VUV radiation fields - have been simulated in the laboratory by associating a pulsed cavity ringdown spectrometer (CRDS) with a supersonic slit jet seeded with PAHs and an ionizing, penning-type, electronic discharge. We have measured for the {\\it first time} the spectra of a series of neutral [3,4] and ionized [5,6] interstellar PAHs analogs in the laboratory. An effort has also been attempted to quantify the mechanisms of ion and carbon nanoparticles production in the free jet expansion and to model our simulation of the diffuse interstellar medium in the laboratory [7]. These experiments provide {\\it unique} information on the spectra of free, large carbon-containing molecules and ions in the gas phase. We are now, for the first time, in the position to directly compare laboratory spectral data on free, cold, PAH ions and carbon nano-sized carbon particles with astronomical observations in the

  1. 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.

  2. Selection of actuator locations for static shape control of large space structures by heuristic integer programing

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Adelman, H. M.

    1984-01-01

    Orbiting spacecraft such as large space antennas have to maintain a highly accurate space to operate satisfactorily. Such structures require active and passive controls to mantain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.

  3. Large transient fault current test of an electrical roll ring. [for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Yenni, Edward J.; Birchenough, Arthur G.

    1991-01-01

    The Space Station Freedom uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals, and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.

  4. A document describing shuttle considerations for the design of large space structures

    NASA Technical Reports Server (NTRS)

    Roebuck, J. A., Jr.

    1981-01-01

    A Shuttle user guide document to aid designers and analysis associated with large space structures projects is described. The format and contents are a compromise designed to satisfy the needs of several levels of users. Special features include checklists and references to source documents as a convenience to very knowledgeable readers. In addition, general, introductory and explanatory text, and art work are included for the reader less familiar with shuttle systems. Also, there are a subject index, glossary, list of acronyms, and many cross references. Throughout the document, there are suggested implications or references to the importance of the included orbiter interfaces material as it pertains to designing and planning large space structures projects. The content of the document is outlined. Shuttle payload accommodations and constraints, connections for orbiter construction fixtures, packaging, and construction space eometry are addressed.

  5. Large-area CdTe diode detector for space application

    NASA Astrophysics Data System (ADS)

    Nakazawa, K.; Takahashi, T.; Watanabe, S.; Sato, G.; Kouda, M.; Okada, Y.; Mitani, T.; Kobayashi, Y.; Kuroda, Y.; Onishi, M.; Ohno, R.; Kitajima, H.

    2003-10-01

    The current status of Schottky CdTe diode detectors, especially in view of their space application for hard X-ray and gamma-ray astronomy, are reported. For practical use in space science, a large-area CdTe diode with a size of 21.5×21.5mm2 and a thickness of 0.5mm was developed. A good energy resolution, 2.8keV (FWHM) at -20°C, and high homogeneity to within 0.2% over the detector were achieved for the spectral performance. This device has successfully passed a series of tests required for its use in space, in view of utilizing Japanese M-V rockets. The tests include the mechanical environment test, vacuum test, long run for weeks and proton-beam radiation. Initial results from a 2×2 segmented electrode large-area device with a guard-ring are also presented.

  6. Definition of ground test for Large Space Structure (LSS) control verification, appendix G

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A Large Space Structure (LSS) ground test facility was developed to help verify LSS passive and active control theories. The facility also perform: (1) subsystem and component testing; (2) remote sensing and control; (3) parameter estimation and model verification; and (4) evolutionary modeling and control. The program is examined as is and looks at the first experiment to be performed in the laboratory.

  7. Preliminary analysis of a flexible instrument mount for large instruments on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A flexible instrument mount for large instruments on the space shuttle is analyzed. Concepts for pointing instruments while in orbit, with weights up to 2000 Kg and dimensions of 2 to 3 m were identified and analyzed. A mechanical concept was selected that can accommodate a set class of scientific instruments such as the LAMAR X-ray experiment with 24 LAMAR telescopes.

  8. Software survey for the avionics test bed. [for large space structures

    NASA Technical Reports Server (NTRS)

    Cobb, J. M.

    1981-01-01

    A survey was conducted to itemize software programs that could possibly be used in the development of an avionics test bed for shuttle attached or autonomous large space structures. The results of this survey are presented. Each program is described on a standard form.

  9. Annular Momentum Control Device (AMCD). Volume 2: Application to a large space telescope

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A conceptual design and set of dynamic equations of a gimbaled AMCD adapted to a Large Space Telescope are presented. Such a system could provide maneuver capability and precision pointing by means of one external gimbal, wheel speed control, and small motions of the rim within the magnetic gap.

  10. Technology for large space systems: A special bibliography with indexes (supplement 03)

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A bibliography containing 217 abstracts addressing the technology for large space systems is presented. State of the art and advanced concepts concerning interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments are represented.

  11. Large segmented UV-optical space telescope using a Hybrid Sensor Active Control (HSAC) architecture

    NASA Astrophysics Data System (ADS)

    Feinberg, Lee D.; Dean, Bruce; Hyde, Tupper; Oegerle, Bill; Bolcar, Matthew R.; Smith, J. Scott

    2009-08-01

    Future large UV-optical space telescopes offer new and exciting windows of scientific parameter space. These telescopes can be placed at L2 and borrow heavily from the James Webb Space Telescope (JWST) heritage. For example, they can have similar deployment schemes, hexagonal mirrors, and use Wavefront Sensing and Control (WFSC) technologies developed for JWST. However, a UV-optical telescope requires a 4x improvement in wavefront quality over JWST to be diffraction-limited at 500 nm. Achieving this tolerance would be difficult using a passive thermal architecture such as the one employed on JWST. To solve this problem, our team has developed a novel Hybrid Sensor Active Control (HSAC) architecture that provides a cost effective approach to building a segmented UV-optical space telescope. In this paper, we show the application of this architecture to the ST-2020 mission concept and summarize the technology development requirements.

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

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1985-01-01

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

  13. Tree-space statistics and approximations for large-scale analysis of anatomical trees.

    PubMed

    Feragen, Aasa; Owen, Megan; Petersen, Jens; Wille, Mathilde M W; Thomsen, Laura H; Dirksen, Asger; de Bruijne, Marleen

    2013-01-01

    Statistical analysis of anatomical trees is hard to perform due to differences in the topological structure of the trees. In this paper we define statistical properties of leaf-labeled anatomical trees with geometric edge attributes by considering the anatomical trees as points in the geometric space of leaf-labeled trees. This tree-space is a geodesic metric space where any two trees are connected by a unique shortest path, which corresponds to a tree deformation. However, tree-space is not a manifold, and the usual strategy of performing statistical analysis in a tangent space and projecting onto tree-space is not available. Using tree-space and its shortest paths, a variety of statistical properties, such as mean, principal component, hypothesis testing and linear discriminant analysis can be defined. For some of these properties it is still an open problem how to compute them; others (like the mean) can be computed, but efficient alternatives are helpful in speeding up algorithms that use means iteratively, like hypothesis testing. In this paper, we take advantage of a very large dataset (N = 8016) to obtain computable approximations, under the assumption that the data trees parametrize the relevant parts of tree-space well. Using the developed approximate statistics, we illustrate how the structure and geometry of airway trees vary across a population and show that airway trees with Chronic Obstructive Pulmonary Disease come from a different distribution in tree-space than healthy ones. Software is available from http://image.diku.dk/aasa/software.php. PMID:24683959

  14. Neural encoding of large-scale three-dimensional space-properties and constraints.

    PubMed

    Jeffery, Kate J; Wilson, Jonathan J; Casali, Giulio; Hayman, Robin M

    2015-01-01

    How the brain represents represent large-scale, navigable space has been the topic of intensive investigation for several decades, resulting in the discovery that neurons in a complex network of cortical and subcortical brain regions co-operatively encode distance, direction, place, movement etc. using a variety of different sensory inputs. However, such studies have mainly been conducted in simple laboratory settings in which animals explore small, two-dimensional (i.e., flat) arenas. The real world, by contrast, is complex and three dimensional with hills, valleys, tunnels, branches, and-for species that can swim or fly-large volumetric spaces. Adding an additional dimension to space adds coding challenges, a primary reason for which is that several basic geometric properties are different in three dimensions. This article will explore the consequences of these challenges for the establishment of a functional three-dimensional metric map of space, one of which is that the brains of some species might have evolved to reduce the dimensionality of the representational space and thus sidestep some of these problems. PMID:26236246

  15. Local stellar kinematics from large astrometric surveys: mapping the Galactic phase-space substructure

    NASA Astrophysics Data System (ADS)

    Lepine, Sebastien

    2016-05-01

    The potential of future large astrometric catalogs for mapping the velocity-space distribution of local stars in the Galaxy is illustrated with a kinematic study of K and M dwarfs in the SUPERBLINK catalog of 2.5 million stars with large proper motions (mu>40 mas/yr). Low mass K and M dwarfs, found in abundance thanks to the faint magnitude limit of the catalog (V<20) provide the densest possible sampling of the [(X,Y,Z),(U,V,W)] phase-space, making them well-suited to map out substructure (so-called "streams") in the velocity-space distributions, as well as variations in said distribution over >100 parsec scale distances. The SUPERBLINK proper motion catalog thus provides kinematic data for ~1.5 million M dwarfs from the Galactic disk population, located within 200 parsecs of the Sun, and for ~180,000 K and M (sub)dwarfs from the Galactic halo population, all within 500 parsecs of the Sun. While the disk dwarfs show clear signs of velocity-space substructure, the distribution of halo subdwarf does appear to be relatively smooth ("streamless") in contrast. Evidence for spatial variations at the few hundred parsec scale is also discussed. The current and unfortunately "blurry" view of the local velocity-space distribution promises to be set in much sharper focus with the upcoming availability of data from the GAIA mission.

  16. A Large Space Simulator (8M X L10M) in Korea

    NASA Astrophysics Data System (ADS)

    Moon, Guee-Won; Cho, Hyokjin; Lee, Sang-Hoon; Seo, Hee-Jun; Choi, Seok-Weon

    2004-08-01

    According to the national space program in Korea, the power dissipation of the future large satellites will be max. 5kW. This power may either be uniformly distributed over the area of the satellite, or it may be concentrated on some faces with a maximum power of 0.5 kW/m2 . To verify the performance of those future satellites under the space environmental conditions, KARI(Korea Aerospace Research Institute) is designing a large space simulator, in which a vacuum and thermal environment is created to simulate the conditions in space. The working pressure inside the vessel will be less than 10-5 torr with two cryopumps (2x60,000l/s). Especially, cryogenic temperature condtions will be simulated by shrouds covering the inside surface of the facility. These shrouds will be made of stainless steel(SUS 304L) and supported by the vessel. The shroud surfaces will be cooled to 77K by liquid nitrogen(LN2), and heated to 423K for bake-out by halogen lamps, which are uniformly distributed all over the internal surface of the shroud. In this paper, we will discuss about our future large thermal vacuum system.

  17. On-orbit damage detection and health monitoring of large space trusses: Status and critical issues

    NASA Technical Reports Server (NTRS)

    Kashangaki, Thomas A. L.

    1991-01-01

    The long lifetimes, delicate nature and stringent pointing requirements of large space structures such as Space Station Freedom and geostationary Earth sciences platforms might require that these spacecraft be monitored periodically for possible damage to the load carrying structures. A review of the literature in damage detection and health monitoring of such structures is presented, along with a candidate structure to be used as a testbed for future work in this field. A unified notation and terminology is also proposed to facilitate comparisons between candidate methods.

  18. A modal analysis and modelling of a lightly damped large space structure

    NASA Astrophysics Data System (ADS)

    George, Scott E.

    1992-06-01

    This study involves the modification to the PACOSS Dynamic Test Article to create a lightly damped representative large space structure with closely spaced, low frequency modes. An experimental modal analysis is performed to recharacterize the low frequency flexible vibration modes. A finite element model is created using MSC/NASTRAN to predict low frequency behavior using both real eigenvalue analysis and frequency response analysis. Then a reduced order model is created and fine-tuned to represent the dynamics of the structure for the identified low frequency modes.

  19. A Scalable Approach to Probabilistic Latent Space Inference of Large-Scale Networks

    PubMed Central

    Yin, Junming; Ho, Qirong; Xing, Eric P.

    2014-01-01

    We propose a scalable approach for making inference about latent spaces of large networks. With a succinct representation of networks as a bag of triangular motifs, a parsimonious statistical model, and an efficient stochastic variational inference algorithm, we are able to analyze real networks with over a million vertices and hundreds of latent roles on a single machine in a matter of hours, a setting that is out of reach for many existing methods. When compared to the state-of-the-art probabilistic approaches, our method is several orders of magnitude faster, with competitive or improved accuracy for latent space recovery and link prediction. PMID:25400487

  20. Spacecraft conceptual design for the 8-meter Advanced Technology Large Aperture Space Telescope (ATLAST)

    NASA Astrophysics Data System (ADS)

    Hopkins, Randall C.; Capizzo, Peter; Fincher, Sharon; Hornsby, Linda S.; Jones, David; Mosier, Gary; Stahl, H. Philip; Thomas, Dan; Thompson, Kevin S.

    2010-07-01

    The Advanced Concepts Office at Marshall Space Flight Center completed a brief spacecraft design study for the 8- meter monolithic Advanced Technology Large Aperture Space Telescope (ATLAST-8m). This spacecraft concept provides all power, communication, telemetry, avionics, guidance and control, and thermal control for the observatory, and inserts the observatory into a halo orbit about the second Sun-Earth Lagrange point. The multidisciplinary design team created a simple spacecraft design that enables component and science instrument servicing, employs articulating solar panels for help with momentum management, and provides precise pointing control while at the same time fast slewing for the observatory.

  1. An optimum organizational structure for a large earth-orbiting multidisciplinary Space Base

    NASA Technical Reports Server (NTRS)

    Ragusa, J. M.

    1973-01-01

    The purpose of this exploratory study was 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. 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 essential finding of this research was that a four-level project type 'total matrix' model will optimize the efficiency and effectiveness of Space Base technologists.

  2. 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.

  3. Spacecraft Conceptual Design for the 8-Meter Advanced Technology Large Aperture Space Telescope (ATLAST)

    NASA Technical Reports Server (NTRS)

    Hopkins, Randall C.; Capizzo, Peter; Fincher, Sharon; Hornsby, Linda S.; Jones, David

    2010-01-01

    The Advanced Concepts Office at Marshall Space Flight Center completed a brief spacecraft design study for the 8-meter monolithic Advanced Technology Large Aperture Space Telescope (ATLAST-8m). This spacecraft concept provides all power, communication, telemetry, avionics, guidance and control, and thermal control for the observatory, and inserts the observatory into a halo orbit about the second Sun-Earth Lagrange point. The multidisciplinary design team created a simple spacecraft design that enables component and science instrument servicing, employs articulating solar panels for help with momentum management, and provides precise pointing control while at the same time fast slewing for the observatory.

  4. Large-Scale Demonstration of Liquid Hydrogen Storage with Zero Boiloff for In-Space Applications

    NASA Technical Reports Server (NTRS)

    Hastings, L. J.; Bryant, C. B.; Flachbart, R. H.; Holt, K. A.; Johnson, E.; Hedayat, A.; Hipp, B.; Plachta, D. W.

    2010-01-01

    Cryocooler and passive insulation technology advances have substantially improved prospects for zero-boiloff cryogenic storage. Therefore, a cooperative effort by NASA s Ames Research Center, Glenn Research Center, and Marshall Space Flight Center (MSFC) was implemented to develop zero-boiloff concepts for in-space cryogenic storage. Described herein is one program element - a large-scale, zero-boiloff demonstration using the MSFC multipurpose hydrogen test bed (MHTB). A commercial cryocooler was interfaced with an existing MHTB spray bar mixer and insulation system in a manner that enabled a balance between incoming and extracted thermal energy.

  5. Definition of ground test for Large Space Structure (LSS) control verification

    NASA Technical Reports Server (NTRS)

    Waites, H. B.; Doane, G. B., III; Tollison, D. K.

    1984-01-01

    An overview for the definition of a ground test for the verification of Large Space Structure (LSS) control is given. The definition contains information on the description of the LSS ground verification experiment, the project management scheme, the design, development, fabrication and checkout of the subsystems, the systems engineering and integration, the hardware subsystems, the software, and a summary which includes future LSS ground test plans. Upon completion of these items, NASA/Marshall Space Flight Center will have an LSS ground test facility which will provide sufficient data on dynamics and control verification of LSS so that LSS flight system operations can be reasonably ensured.

  6. Development of a large space robot - A multi-segment approach. I

    NASA Technical Reports Server (NTRS)

    Spanos, P. D.; Berka, Reginald B.

    1993-01-01

    A concept of multisegment robot (of a class of large space cranes) is developed for use in space-based construction operations. The robot consists of a collection of segments, which are pinned together to form a snakelike configuration, with a single degree of freedom representing rotation being retained at each pinned connection and with reaction flywheels suspended within each segment for the control necessary to position each body segment. Algorithms are developed for positioning this serpentine robot to a prescribed location and orientation. A multibody dynamics simulation is used to investigate the behavior and interactions of the robot, demonstrating its viability.

  7. Major technological innovations introduced in the large antennas of the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Imbriale, W. A.

    2002-01-01

    The NASA Deep Space Network (DSN) is the largest and most sensitive scientific, telecommunications and radio navigation network in the world. Its principal responsibilities are to provide communications, tracking, and science services to most of the world's spacecraft that travel beyond low Earth orbit. The network consists of three Deep Space Communications Complexes. Each of the three complexes consists of multiple large antennas equipped with ultra sensitive receiving systems. A centralized Signal Processing Center (SPC) remotely controls the antennas, generates and transmits spacecraft commands, and receives and processes the spacecraft telemetry.

  8. Building ISOC Status Displays for the Large AreaTelescope aboard the Gamma Ray Large Area Space Telescope (GLAST) Observatory

    SciTech Connect

    Ketchum, Christina; /SLAC

    2006-09-01

    In September 2007 the Gamma Ray Large Area Space Telescope (GLAST) is scheduled to launch aboard a Delta II rocket in order to put two high-energy gamma-ray detectors, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM) into low earth orbit. The Instrument Science Operations Center (ISOC) at SLAC is responsible for the LAT operations for the duration of the mission, and will therefore build an operations center including a monitoring station at SLAC to inform operations staff and visitors of the status of the LAT instrument and GLAST. This monitoring station is to include sky maps showing the location of GLAST in its orbit as well as the LAT's projected field of view on the sky containing known gamma-ray sources. The display also requires a world map showing the locations of GLAST and three Tracking and Data Relay Satellites (TDRS) relative to the ground, their trail lines, and ''footprint'' circles indicating the range of communications for each satellite. The final display will also include a space view showing the orbiting and pointing information of GLAST and the TDRS satellites. In order to build the displays the astronomy programs Xephem, DS9, SatTrack, and STK were employed to model the position of GLAST and pointing information of the LAT instrument, and the programming utilities Python and Cron were used in Unix to obtain updated information from database and load them into the programs at regular intervals. Through these methods the indicated displays were created and combined to produce a monitoring display for the LAT and GLAST.

  9. Fault-tolerant control of large space structures using the stable factorization approach

    NASA Technical Reports Server (NTRS)

    Razavi, H. C.; Mehra, R. K.; Vidyasagar, M.

    1986-01-01

    Large space structures are characterized by the following features: they are in general infinite-dimensional systems, and have large numbers of undamped or lightly damped poles. Any attempt to apply linear control theory to large space structures must therefore take into account these features. Phase I consisted of an attempt to apply the recently developed Stable Factorization (SF) design philosophy to problems of large space structures, with particular attention to the aspects of robustness and fault tolerance. The final report on the Phase I effort consists of four sections, each devoted to one task. The first three sections report theoretical results, while the last consists of a design example. Significant results were obtained in all four tasks of the project. More specifically, an innovative approach to order reduction was obtained, stabilizing controller structures for plants with an infinite number of unstable poles were determined under some conditions, conditions for simultaneous stabilizability of an infinite number of plants were explored, and a fault tolerance controller design that stabilizes a flexible structure model was obtained which is robust against one failure condition.

  10. Observation of quantum particles on a large space-time scale

    NASA Astrophysics Data System (ADS)

    Landau, L. J.

    1994-10-01

    A quantum particle observed on a sufficiently large space-time scale can be described by means of classical particle trajectories. The joint distribution for large-scale multiple-time position and momentum measurements on a nonrelativistic quantum particle moving freely in R v is given by straight-line trajectories with probabilities determined by the initial momentum-space wavefunction. For large-scale toroidal and rectangular regions the trajectories are geodesics. In a uniform gravitational field the trajectories are parabolas. A quantum counting process on free particles is also considered and shown to converge in the large-space-time limit to a classical counting process for particles with straight-line trajectories. If the quantum particle interacts weakly with its environment, the classical particle trajectories may undergo random jumps. In the random potential model considered here, the quantum particle evolves according to a reversible unitary one-parameter group describing elastic scattering off static randomly distributed impurities (a quantum Lorentz gas). In the large-space-time weak-coupling limit a classical stochastic process is obtained with probability one and describes a classical particle moving with constant speed in straight lines between random jumps in direction. The process depends only on the ensemble value of the covariance of the random field and not on the sample field. The probability density in phase space associated with the classical stochastic process satisfies the linear Boltzmann equation for the classical Lorentz gas, which, in the limit h→0, goes over to the linear Landau equation. Our study of the quantum Lorentz gas is based on a perturbative expansion and, as in other studies of this system, the series can be controlled only for small values of the rescaled time and for Gaussian random fields. The discussion of classical particle trajectories for nonrelativistic particles on a macroscopic spacetime scale applies also to

  11. Use of the moon and the large space telescope as an extrasolar planet detection system

    NASA Technical Reports Server (NTRS)

    Matloff, G. L.; Fennelly, A. J.

    1974-01-01

    Roman (1959), Spitzer (1962), and Huang (1973) have discussed photometric detection of extrasolar planets using a 3-m space telescope such as the Large Space Telescope (LST). A space telescope could be an extrasolar planet detection system if used in conjunction with an occulter placed 10,000 km in front of the telescope. The occulter would reduce the amount of light received from the star under observation. For a semi-infinite plane occulter 10,000 km in front of the telescope, Spitzer and Huang's results indicate that a Jupiter-like planet would be observed with a signal/noise of 1.00, for observations at 0.4 micron using a 3-m telescope like the LST.

  12. Results of the NASA Loya Jirga II: large space telescopes and infrastructure support

    NASA Astrophysics Data System (ADS)

    Friedman, Ed; Moe, Rud; Graf, Paul; Oschmann, Jim

    2005-08-01

    Two recent meetings sponsored by NASA have helped define the in-space capabilities (technology, operations and infrastructure) necessary to enable and enhance future space missions. The activities preceded NASA's roadmapping efforts that occurred from the fall of 2004 to spring of 2005. These Loya Jirga meetings (using a Pashto expression for "grand council') involved about 100 representatives from industry, academia and government. Three mission concepts were used to guide the products of the meetings: manned missions to Mars, large serviceable space telescopes, and unmanned nuclear-powered missions to the outer planets. The deliberations produced roadmaps for the timing and type of developments needed to support these missions, the interconnections of capabilities with missions and other details that can be used to guide investment planning.

  13. Control of large flexible spacecraft by the independent modal-space control method

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Shenar, J.

    1984-01-01

    The problem of control of a large-order flexible structure in the form of a plate-like lattice by the Independent Modal-Space Control (IMSC) method is presented. The equations of motion are first transformed to the modal space, thus obtaining internal (plant) decoupling of the system. Then, the control laws are designed in the modal space for each mode separately, so that the modal equations of motion are rendered externally (controller) decoupled. This complete decoupling applies both to rigid-body modes and elastic modes. The application of linear optimal control, in conjunction with a quadratic performance index, is first reviewed. A solution for high-order systems is proposed here by the IMSC method, whereby the problem is reduced to a number of modal minimum-fuel problems for the controlled modes.

  14. Advanced Technology Large-Aperture Space Telescope: Science Drivers and Technology Developments

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Brown, Tom; Sembach, Kenneth; Glavallsco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Philip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

    2012-01-01

    The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8- to 16-m ultraviolet optical near Infrared space observatory for launch in the 2025 to 2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including: Is there life elsewhere in the Galaxy? We present a range of science drivers and the resulting performance requirements for ATLAST (8- to 16-marcsec angular resolution, diffraction limited imaging at 0.5 micron wavelength, minimum collecting area of 45 sq m, high sensitivity to light wavelengths from 0.1 to 2.4 micron, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to that of current generation observatory-class space missions.

  15. Some thoughts on the management of large, complex international space ventures

    NASA Technical Reports Server (NTRS)

    Lee, T. J.; Kutzer, Ants; Schneider, W. C.

    1992-01-01

    Management issues relevant to the development and deployment of large international space ventures are discussed with particular attention given to previous experience. Management approaches utilized in the past are labeled as either simple or complex, and signs of efficient management are examined. Simple approaches include those in which experiments and subsystems are developed for integration into spacecraft, and the Apollo-Soyuz Test Project is given as an example of a simple multinational approach. Complex approaches include those for ESA's Spacelab Project and the Space Station Freedom in which functional interfaces cross agency and political boundaries. It is concluded that individual elements of space programs should be managed by individual participating agencies, and overall configuration control is coordinated by level with a program director acting to manage overall objectives and project interfaces.

  16. 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.

  17. Selection of actuator locations for static shape control of large space structures by heuristic integer programing

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Adelman, H. M.

    1985-01-01

    Orbiting spacecraft such as large space antennas have to maintain a highly accurate shape to operate satisfactorily. Such structures require active and passive controls to maintain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.

  18. Decoupled control analysis of a large flexible space antenna with linear quadratic regulator comparisons

    NASA Technical Reports Server (NTRS)

    Young, J. W.; Hamer, H. A.; Johnson, K. G.

    1984-01-01

    A decoupled-control analysis was performed for a large flexible space antenna. Control involved commanding changes in the rigid-body modes or nulling disturbances in the flexible modes. The study provides parametric-type data which could be useful in the final design of a large space antenna control system. Results are presented to illustrate the effect on control requirements of (1) the number of modes controlled; (2) the number, type, and location of control actuators; and (3) variations in the closed-loop dynamics of the control system. Comparisons are given between the decoupled-control results and those obtained by using a linear quadratic regulator approach. Time history responses are presented to illustrate the effects of the control procedures.

  19. Model correlation and damage location for large space truss structures: Secant method development and evaluation

    NASA Technical Reports Server (NTRS)

    Smith, Suzanne Weaver; Beattie, Christopher A.

    1991-01-01

    On-orbit testing of a large space structure will be required to complete the certification of any mathematical model for the structure dynamic response. The process of establishing a mathematical model that matches measured structure response is referred to as model correlation. Most model correlation approaches have an identification technique to determine structural characteristics from the measurements of the structure response. This problem is approached with one particular class of identification techniques - matrix adjustment methods - which use measured data to produce an optimal update of the structure property matrix, often the stiffness matrix. New methods were developed for identification to handle problems of the size and complexity expected for large space structures. Further development and refinement of these secant-method identification algorithms were undertaken. Also, evaluation of these techniques is an approach for model correlation and damage location was initiated.

  20. 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.

  1. Preliminary assessment of the vacuum environment in the wake of large space vehicles

    NASA Technical Reports Server (NTRS)

    Oran, W. A.; Naumann, R. J.

    1977-01-01

    The vacuum environment in the wake region of presently planned large space vehicles is calculated using simplified models of the particle fluxes from the various sources. The fluxes which are calculated come directly from the ambient, are due to ambient particles backscattered from spacecraft emissions, and are due to self scattering of spacecraft emissions. Using nominal values for the surface emissions, the flux density environment behind a large unmanned craft at 550 km altitude is calculated. Calculations indicate that the flux density on a wake vacuum experiment conducted in the vicinity of the shuttle is substantially greater than that behind unmanned craft.

  2. Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Abplanalp, Laura; Arnold, William

    2014-01-01

    ASTRO2010 Decadal stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. AMTD builds on the state of art (SOA) defined by over 30 years of monolithic & segmented ground & space-telescope mirror technology to mature six key technologies. AMTD is deliberately pursuing multiple design paths to provide the science community with op-tions to enable either large aperture monolithic or segmented mirrors with clear engineering metrics traceable to science requirements.

  3. A hybrid approach to test-analysis-model development for large space structures

    NASA Technical Reports Server (NTRS)

    Kammer, D. C.

    1991-01-01

    The present FEM reduction method for the generation of test-analysis-models (TAMs) in test-analysis correlation addresses contentions that the current modal TAM is hypersensitive to differences between test model shapes and analysis mode shapes, thereby generating large off-diagonal terms within the orthogonality and cross-orthogonality matrices employed in test-analysis mode-shape correlation. A hybrid TAM methodology is accordingly developed which combines the exact representation of the FEM target modes from the modal TAM with the more accurate TAM representation of the residual modes; the superior residual dynamics representation of the hybrid TAM is demonstrated for a detailed representation of a large space structure.

  4. 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.

  5. Technology for large space systems: A special bibliography with indexes (supplement 01)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This bibliography lists 180 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1979 and June 30, 1979. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, and flight experiments.

  6. Technology for large space systems: A bibliography with indexes (supplement 20)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This bibliography lists 694 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July, 1988 and December, 1988. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion.

  7. Technology for large space systems: A bibliography with indexes (supplement 22)

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This bibliography lists 1077 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion.

  8. Conceptual design of the scientific instrument arrangement for the large space telescope

    NASA Technical Reports Server (NTRS)

    Zurasky, J. L.

    1974-01-01

    A description of the scientific instrument arrangement for the large space telescope (LST) is given, with some of the rationale for selecting this concept. The first section of this report describes the basic configuration and was designed for an f/20 telescope focal plane. The subsequent LSTWG meeting held in November gave some redirection to the scientific requirements, and these changes are described in the section, Configuration Update.

  9. Control system design for the large space systems technology reference platform

    NASA Technical Reports Server (NTRS)

    Edmunds, R. S.

    1982-01-01

    Structural models and classical frequency domain control system designs were developed for the large space systems technology (LSST) reference platform which consists of a central bus structure, solar panels, and platform arms on which a variety of experiments may be mounted. It is shown that operation of multiple independently articulated payloads on a single platform presents major problems when subarc second pointing stability is required. Experiment compatibility will be an important operational consideration for systems of this type.

  10. Control structure interactions in large space structures Analysis using energy approach. [for constant and pulsed thrusters

    NASA Technical Reports Server (NTRS)

    Shrivastava, S. K.; Ried, R. C.; Manoharan, M. G.

    1983-01-01

    A simple energy approach to study the problem of control structure interactions in large space structures is presented. For the illustrative cases of free-free beam and free rectangular plate, the vibrational energy imparted during operation of constant and pulsed thrusters is found in a nondimensional form. Then based on a parametric study, suggestions are made on the choice of the thruster location and parameters to minimize the control structure interactions.

  11. Technology for large space systems: A bibliography with indexes (supplement 08)

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This bibliography lists 414 reports, articles and other documents introduced into the NASA scientific and technical information system. It provides helpful information to the researcher, manager, and designer in technology development and mission design in the area of Large Space System Technology. Subject matter is grouped according to systems, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems.

  12. Controller design approaches for large space structures using LQG control theory. [Linear Quadratic Gaussian

    NASA Technical Reports Server (NTRS)

    Joshi, S. M.; Groom, N. J.

    1979-01-01

    The paper presents several approaches for the design of reduced order controllers for large space structures. These approaches are shown to be based on LQG control theory and include truncation, modified truncation regulators and estimators, use of higher order estimators, selective modal suppression, and use of polynomial estimators. Further, the use of direct sensor feedback, as opposed to a state estimator, is investigated for some of these approaches. Finally, numerical results are given for a long free beam.

  13. Phase A reaction control system design for the Large Space Telescope (LST)

    NASA Technical Reports Server (NTRS)

    Price, W. B.

    1972-01-01

    The design of a reaction control system (RCS) for the Large Space Telescope is discussed. The primary requirement for the RCS is to serve as an emergency backup control system to the primary attitude control system. A regulated gaseous nitrogen RCS was selected. The operation of the system and its individual components is described. The principal design goals of the RCS were to minimize contamination effects, make use of existing components, and modularize the system to provide ease in manned orbital maintenance.

  14. Study of auxiliary propulsion requirements for large space systems, volume 2

    NASA Technical Reports Server (NTRS)

    Smith, W. W.; Machles, G. W.

    1983-01-01

    A range of single shuttle launched large space systems were identified and characterized including a NASTRAN and loading dynamics analysis. The disturbance environment, characterization of thrust level and APS mass requirements, and a study of APS/LSS interactions were analyzed. State-of-the-art capabilities for chemical and ion propulsion were compared with the generated propulsion requirements to assess the state-of-the-art limitations and benefits of enhancing current technology.

  15. Technology for large space systems: A bibliography with indexes (supplement 09)

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This bibliography lists 414 reports, articles and other documents introduced into the NASA scientific and technical information system between January 1, 1983 and June 30, 1983. Information on technology development and mission design in the area of Large Space System Technology is provided. Subject matter is grouped according to systems, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics. advanced materials, assembly concepts, propulsion, and solar power satellite systems.

  16. Technology for large space systems: A special bibliography with indexes (supplement 04)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This bibliography lists 259 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1980 and December 31, 1980. Its purpose is to provide information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology Program. Subject matter is grouped according to systems, interactive analysis and design. Structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments.

  17. Technology for large space systems: A bibliography with indexes (supplement 10)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The bibliography lists 408 reports, articles and other documents introduced into the NASA scientific and technical information system to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of large space system technology. Subject matter is grouped according to systems, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems.

  18. The two axis motion simulator for the large space simulator at ESTEC (European Space Research and Technology Center)

    NASA Technical Reports Server (NTRS)

    Beckel, Kurt A.; Hutchison, Joop

    1988-01-01

    The Large Space Simulator at the European Space Research and Technology Center (ESTEC) has been recently equipped with a motion simulator capable of handling test items of 5 tons mass and having a volume of 7m in diameter and a length of 7m. The motion simulator has a modular set-up. It consists of a spinbox as a basic unit on which the test article is mounted and which allows continuous rotation (spin) . This spinbox can be used in two operational configurations; the spin axis is vertical to 30 degrees when mounted on a gimbalstand; and the spin axis is horizontal when mounted on a turntable-yoke combination. The turntable provides rotation within plus or minus 90 degrees. This configuration allows one to bring a test article to all possible relative positions viv-a-vis the sun vector (which is horizontal in this case). The spinbox allows fast rotation between 1 to 6 rpm or slow rotation between 1 to 25 rotations per day as well as positioning within plus or minus 0.4 degrees accuracy.

  19. Initial operational capability of the ASTREX large space structures test bed

    NASA Technical Reports Server (NTRS)

    Norris, G. A.

    1989-01-01

    Future DOD, NASA, and SDI space systems will be larger than any spacecraft flown before. The economics of placing these large space systems (LSS) into orbit dictates that they be as low in mass as possible. The combination of very large size and relatively low mass produces systems which possess little structural rigidity. This flexibility causes severe technical problems when combined with the precise shape and pointing requirements associated with many future LSS missions. Development of new control technologies which can solve these problems and enable future LSS missions is under way, but a test bed is needed for demonstration and evaluation of the emerging control hardware (sensors and actuators) and methodologies. In particular, the need exists for a facility which enables both large angle slewing and subsequent pointing/shape control of a variety of flexible bodies. The Air Force Astronautics Laboratory (AFAL) has conceived the Advanced Space Structures Technology Research Experiments (ASTREX) facility to fill this need. An overview of the ASTREX facility is given.

  20. A Preliminary Seismic Analysis of 51 Pegasi: Large and Small Spacings from Standard Models

    NASA Astrophysics Data System (ADS)

    Murphy, Eric J.; Demarque, Pierre; Guenther, D. B.

    2004-04-01

    We present a preliminary theoretical seismic study of the astronomically famous star 51 Peg. This is done by first performing a detailed analysis within the Hertzsprung-Russell diagram (HRD). Using the Yale stellar evolution code (YREC), a grid of stellar evolutionary tracks has been constructed for the masses 1.00, 1.05, and 1.10 Msolar, in the metallicity range Z=0.024-0.044, and for values of the Galactic helium enrichment ratio (ΔY/ΔZ) in the range 0-2.5. Along these evolutionary tracks, we select 75 stellar model candidates that fall within the 51 Peg observational error box in the HRD (all turn out to have masses of 1.05 and 1.10Msolar). The corresponding allowable age range for these models, which depends sensitively on the parameters of the model, is relatively large, ~2.5-5.5 Gyr. For each of the 75 models, a nonradial pulsation analysis is carried out and the large- and small-frequency spacings are calculated. The results show that just measuring the large- and small-frequency spacings will greatly reduce the present uncertainties in the derived physical parameters and in the age of 51 Peg. Finally, we briefly discuss refinements in the physics of the models and in the method of analysis, which will have to be included in future models to make the best of the precise frequency determinations expected from space observations.

  1. Stability of large DC power systems using switching converters, with application to the International Space Station

    SciTech Connect

    Gholdston, E.W.; Karimi, K.; Lee, F.C.; Rajagopalan, J.; Panov, Y.; Manners, B.

    1996-12-31

    As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters are playing an ever larger role in power conditioning and control.When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense and Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a clear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing.

  2. An Engineering Design Reference Mission for a Future Large-Aperture UVOIR Space Observatory

    NASA Astrophysics Data System (ADS)

    Thronson, Harley A.; Bolcar, Matthew R.; Clampin, Mark; Crooke, Julie A.; Redding, David; Rioux, Norman; Stahl, H. Philip

    2016-01-01

    From the 2010 NRC Decadal Survey and the NASA Thirty-Year Roadmap, Enduring Quests, Daring Visions, to the recent AURA report, From Cosmic Birth to Living Earths, multiple community assessments have recommended development of a large-aperture UVOIR space observatory capable of achieving a broad range of compelling scientific goals. Of these priority science goals, the most technically challenging is the search for spectroscopic biomarkers in the atmospheres of exoplanets in the solar neighborhood. Here we present an engineering design reference mission (EDRM) for the Advanced Technology Large-Aperture Space Telescope (ATLAST), which was conceived from the start as capable of breakthrough science paired with an emphasis on cost control and cost effectiveness. An EDRM allows the engineering design trade space to be explored in depth to determine what are the most demanding requirements and where there are opportunities for margin against requirements. Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. The ATLAST observatory is designed to operate at a Sun-Earth L2 orbit, which provides a stable thermal environment and excellent field of regard. Our reference designs have emphasized a serviceable 36-segment 9.2 m aperture telescope that stows within a five-meter diameter launch vehicle fairing. As part of our cost-management effort, this particular reference mission builds upon the engineering design for JWST. Moreover, it is scalable to a variety of launch vehicle fairings. Performance needs developed under the study are traceable to a variety of additional reference designs, including options for a monolithic primary mirror.

  3. 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.

  4. Computational Methodologies for Real-Space Structural Refinement of Large Macromolecular Complexes.

    PubMed

    Goh, Boon Chong; Hadden, Jodi A; Bernardi, Rafael C; Singharoy, Abhishek; McGreevy, Ryan; Rudack, Till; Cassidy, C Keith; Schulten, Klaus

    2016-07-01

    The rise of the computer as a powerful tool for model building and refinement has revolutionized the field of structure determination for large biomolecular systems. Despite the wide availability of robust experimental methods capable of resolving structural details across a range of spatiotemporal resolutions, computational hybrid methods have the unique ability to integrate the diverse data from multimodal techniques such as X-ray crystallography and electron microscopy into consistent, fully atomistic structures. Here, commonly employed strategies for computational real-space structural refinement are reviewed, and their specific applications are illustrated for several large macromolecular complexes: ribosome, virus capsids, chemosensory array, and photosynthetic chromatophore. The increasingly important role of computational methods in large-scale structural refinement, along with current and future challenges, is discussed. PMID:27145875

  5. Graph theory approach to the eigenvalue problem of large space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Bainum, P. M.

    1981-01-01

    Graph theory is used to obtain numerical solutions to eigenvalue problems of large space structures (LSS) characterized by a state vector of large dimensions. The LSS are considered as large, flexible systems requiring both orientation and surface shape control. Graphic interpretation of the determinant of a matrix is employed to reduce a higher dimensional matrix into combinations of smaller dimensional sub-matrices. The reduction is implemented by means of a Boolean equivalent of the original matrices formulated to obtain smaller dimensional equivalents of the original numerical matrix. Computation time becomes less and more accurate solutions are possible. An example is provided in the form of a free-free square plate. Linearized system equations and numerical values of a stiffness matrix are presented, featuring a state vector with 16 components.

  6. Optimal estimation of large structure model errors. [in Space Shuttle controller design

    NASA Technical Reports Server (NTRS)

    Rodriguez, G.

    1979-01-01

    In-flight estimation of large structure model errors is usually required as a means of detecting inevitable deficiencies in large structure controller/estimator models. The present paper deals with a least-squares formulation which seeks to minimize a quadratic functional of the model errors. The properties of these error estimates are analyzed. It is shown that an arbitrary model error can be decomposed as the sum of two components that are orthogonal in a suitably defined function space. Relations between true and estimated errors are defined. The estimates are found to be approximations that retain many of the significant dynamics of the true model errors. Current efforts are directed toward application of the analytical results to a reference large structure model.

  7. Feasibility analysis of large length-scale thermocapillary flow experiment for the International Space Station

    NASA Astrophysics Data System (ADS)

    Alberts, Samantha J.

    The investigation of microgravity fluid dynamics emerged out of necessity with the advent of space exploration. In particular, capillary research took a leap forward in the 1960s with regards to liquid settling and interfacial dynamics. Due to inherent temperature variations in large spacecraft liquid systems, such as fuel tanks, forces develop on gas-liquid interfaces which induce thermocapillary flows. To date, thermocapillary flows have been studied in small, idealized research geometries usually under terrestrial conditions. The 1 to 3m lengths in current and future large tanks and hardware are designed based on hardware rather than research, which leaves spaceflight systems designers without the technological tools to effectively create safe and efficient designs. This thesis focused on the design and feasibility of a large length-scale thermocapillary flow experiment, which utilizes temperature variations to drive a flow. The design of a helical channel geometry ranging from 1 to 2.5m in length permits a large length-scale thermocapillary flow experiment to fit in a seemingly small International Space Station (ISS) facility such as the Fluids Integrated Rack (FIR). An initial investigation determined the proposed experiment produced measurable data while adhering to the FIR facility limitations. The computational portion of this thesis focused on the investigation of functional geometries of fuel tanks and depots using Surface Evolver. This work outlines the design of a large length-scale thermocapillary flow experiment for the ISS FIR. The results from this work improve the understanding thermocapillary flows and thus improve technological tools for predicting heat and mass transfer in large length-scale thermocapillary flows. Without the tools to understand the thermocapillary flows in these systems, engineers are forced to design larger, heavier vehicles to assure safety and mission success.

  8. 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

  9. Solar Sail - Fresnel Zone Plate Lens for a Large Space Based Telescope

    SciTech Connect

    Early, J T

    2002-02-13

    A Fresnel zone plate lens made with solar sail material could be used as the primary optic for a very large aperture telescope on deep space probes propelled by solar sails. The large aperture telescope capability could enable significant science on fly-by missions to the asteroids, Pluto, Kuiper belt or the tort cloud and could also enable meaningful interstellar fly-by missions for laser propelled sails. This type of lens may also have some potential for laser communications and as a solar concentrator. The techniques for fabrication of meter size and larger Fresnel phase plate optics are under development at LLNL, and we are extending this technology to amplitude zone plates made from sail materials. Corrector optics to greatly extend the bandwidth of these Fresnel optics will be demonstrated in the future. This novel telescope concept will require new understanding of the fabrication, deployment and control of gossamer space structures. It will also require new materials technology for fabricating these optics and understanding their long term stability in a space environment.

  10. Technical issues in the conduct of large space platform experiments in plasma physics and geoplasma sciences

    NASA Technical Reports Server (NTRS)

    Szuszczewicz, Edward P.

    1986-01-01

    Large, permanently-manned space platforms can provide exciting opportunities for discoveries in basic plasma and geoplasma sciences. The potential for these discoveries will depend very critically on the properties of the platform, its subsystems, and their abilities to fulfill a spectrum of scientific requirements. With this in mind, the planning of space station research initiatives and the development of attendant platform engineering should allow for the identification of critical science and technology issues that must be clarified far in advance of space station program implementation. An attempt is made to contribute to that process, with a perspective that looks to the development of the space station as a permanently-manned Spaceborne Ionospheric Weather Station. The development of this concept requires a synergism of science and technology which leads to several critical design issues. To explore the identification of these issues, the development of the concept of an Ionospheric Weather Station will necessarily touch upon a number of diverse areas. These areas are discussed.

  11. Fabrication technique of large-scale lightweight SiC space mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Ge; Zhao, Rucheng; Zhao, Wenxing

    2007-12-01

    Silicon carbide (SiC) is a new type candidate material for large-scale lightweight space mirror. Its low thermal distortion, high stiffness, high optical quality, and its dimensional stability are better than other traditional optical substrate materials such as ULE, Zerodure, Beryllium (Be) and so on. In this paper, the lightweight silicon carbide space mirror blank was fabricated by reaction sintering. As a space born mirror material, silicon carbide must be an optical grade ceramic. So we prepared the silicon carbide green body with gel-casting method. Then some carbon materials were supplemented into the green body which will bring reaction-sintering with silicon in a vacuum furnace during 1500-1600°C, ultimately the reaction bonded silicon carbide was made. The diameter of SiC space mirror blank we have made is 680mm. If expanding the size of the vacuum furnace, bigger mirror blank can be obtained. The test results show that the mechanical and thermal properties of RB-SiC are excellent with bending strength of 350MPa, fracture toughness of 4.1 MPaÂ.m1/2 and coefficient of thermal expansion(CET) of 2.67×10-6/K. The surface roughness(RMS) could be better than 3nm.

  12. A mobile work station concept for mechanically aided astronaut assembly of large space trusses

    NASA Technical Reports Server (NTRS)

    Heard, W. L., Jr.; Bush, H. G.; Wallson, R. E.; Jensen, J. K.

    1983-01-01

    This report presents results of a series of truss assembly tests conducted to evaluate a mobile work station concept intended to mechanically assist astronaut manual assembly of erectable space trusses. The tests involved assembly of a tetrahedral truss beam by a pair of test subjects with and without pressure (space) suits, both in Earth gravity and in simulated zero gravity (neutral buoyancy in water). The beam was assembled from 38 identical graphite-epoxy nestable struts, 5.4 m in length with aluminum quick-attachment structural joints. Struts and joints were designed to closely simulate flight hardware. The assembled beam was approximately 16.5 m long and 4.5 m on each of the four sides of its diamond-shaped cross section. The results show that average in-space assembly rates of approximately 38 seconds per strut can be expected for struts of comparable size. This result is virtually independent of the overall size of the structure being assembled. The mobile work station concept would improve astronaut efficiency for on-orbit manual assembly of truss structures, and also this assembly-line method is highly competitive with other construction methods being considered for large space structures.

  13. Unique Programme of Indian Centre for Space Physics using large rubber Balloons

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Sandip Kumar; Sarkar, Ritabrata; Bhowmick, Debashis; Chakraborty, Subhankar

    Indian Centre for Space Physics (ICSP) has developed a unique capability to pursue space based studies at a very low cost. Here, large rubber balloons are sent to near space (~ 40km) with payloads of less than 4kg weight. These payloads can be cosmic ray detectors, X-ray detectors, muon detectors apart from communication device, GPS, and nine degrees of freedom measuring capabilities. With two balloons in orbiter-launcher configuration, ICSP has been able to conduct long duration flights upto 12 hours. ICSP has so far sent 56 Dignity missions to near space and obtained Cosmic Ray and muon variation on a regular basis, dynamical spectrum of solar flares and gamma ray burst apart from other usual parameters such as wind velocity components, temperature and pressure variations etc. Since all the payloads are retrieved by parachutes, the cost per mission remains very low, typically around USD1000.00. The preparation time is low. Furthermore, no special launching area is required. In principle, such experiments can be conducted on a daily basis, if need be. Presently, we are also incorporating studies relating to earth system science such as Ozone, aerosols, micro-meteorites etc.

  14. 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

  15. Application of optical distributed sensing and computation to control of large space structures

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1992-01-01

    A real time holographic sensing technique is introduced and its advantages are investigated from the filtering and control point of view. A feature of holographic sensing is its capability to make distributed measurements of the position and velocity of moving objects, such as a vibrating flexible space structure. This work is based upon the distributed parameter models of linear time invariant systems, particularly including the linear oscillator equations describing the vibration of large flexible space structures. The general conclusion is that application of optical distributed sensors bring gains in the situation where Kalman filtering is necessary for state estimation. In this case, both steady state and transient filtering error covariance become smaller. This in turn results in smaller cost in the LQG problem.

  16. Need, utilization, and configuration of a large, multi-G centrifuge on the Space Station

    NASA Technical Reports Server (NTRS)

    Bonting, Sjoerd L.

    1987-01-01

    A large, multi-g centrifuge is required on the Space Station (1) to provide valid 1-g controls for the study of zero-g effects on animals and plants and to study readaptation to 1 g; (2) to store animals at 1 g prior to short-term zero-g experimentation; (3) to permit g-level threshold studies of gravity effects. These requirements can be met by a 13-ft-diam., center-mounted centrifuge, on which up to 48 modular habitats with animals (squirrel monkey, rat, mouse) and plants are attached. The advantages of locating this centrifuge with the vivarium, a common environmental control and life support system, a general-purpose work station and storage of food, water, and supplies in an attached short module, are elaborated. Servicing and operation of the centrifuge, as well as minimizing its impact on other Space Station functions are also considered.

  17. 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.

  18. Definition of ground test for verification of large space structure control

    NASA Technical Reports Server (NTRS)

    Glaese, John R.

    1994-01-01

    Under this contract, the Large Space Structure Ground Test Verification (LSSGTV) Facility at the George C. Marshall Space Flight Center (MSFC) was developed. Planning in coordination with NASA was finalized and implemented. The contract was modified and extended with several increments of funding to procure additional hardware and to continue support for the LSSGTV facility. Additional tasks were defined for the performance of studies in the dynamics, control and simulation of tethered satellites. When the LSSGTV facility development task was completed, support and enhancement activities were funded through a new competitive contract won by LCD. All work related to LSSGTV performed under NAS8-35835 has been completed and documented. No further discussion of these activities will appear in this report. This report summarizes the tether dynamics and control studies performed.

  19. Laboratory Spectroscopy of Large Carbon Molecules and Ions in Support of Space Missions

    NASA Technical Reports Server (NTRS)

    Salana, Farid; Tan, X.; Cami, J.; Remy, J.

    2006-01-01

    One of the major objectives of Laboratory Astrophysics is the optimization of data return from space missions by measuring spectra of atomic and molecular species in laboratory environments that mimic interstellar conditions (WhitePaper (2002, 2006)). Among interstellar species, PAHs are an important and ubiquitous component of carbon-bearing materials that represents a particularly difficult challenge for gas-phase laboratory studies. We present the absorption spectra of jet-cooled neutral and ionized PAHs and discuss the implications for astrophysics. The harsh physical conditions of the interstellar medium have been simulated in the laboratory. We are now, for the first time, in the position to directly compare laboratory spectra of PAHs and carbon nanoparticles with astronomical observations. This new phase offers tremendous opportunities for the data analysis of current and upcoming space missions geared toward the detection of large aromatic systems (HST/COS, FUSE, JWST, Spitzer).

  20. Simulation of on-orbit modal tests of large space structures

    NASA Technical Reports Server (NTRS)

    Blelloch, Paul; Engelhardt, Charlie; Hunt, David L.

    1990-01-01

    This paper describes a procedure to analytically simulate a modal test of an on-orbit large space structure (LSS), extract the modal properties, and evaluate the success of the modal test. This procedure addresses some of the major challenges to performing an on-orbit modal test of an LSS including high modal density, low frequency modes, and limitations in excitation capabilities. A finite element model of the orbiting structure is used to predict acceleration responses due to thruster excitations, time-domain modal extraction methods are used to estimate the modal properties, and comparison of frequencies and cross-orthogonality values is used to evaluate the success of the modal test. Several alternative excitation patterns and sensor arrangements were evaluated using a space station model as an example. Results of the simulations indicate that the choice of excitation functions is critical to the success of the test.

  1. 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; Wood, Lloyd

    2010-01-01

    We use Delay-Tolerant Networking (DTN) to break control loops between space-ground communication links and ground-ground communication links to increase overall file delivery efficiency, as well as to enable large files to be proactively fragmented and received across multiple ground stations. DTN proactive fragmentation and reactive fragmentation were demonstrated from the UK-DMC satellite using two independent ground stations. The files were reassembled at a bundle agent, located at Glenn Research Center in Cleveland Ohio. The first space-based demonstration of this occurred on September 30 and October 1, 2009. This paper details those experiments. Communication, delay-tolerant networking, DTN, satellite, Internet, protocols, bundle, IP, TCP.

  2. Mechanical joints and large components for pathfinder in-space assembly and construction

    NASA Technical Reports Server (NTRS)

    Finckenor, Jeff; Thomas, Frank

    1990-01-01

    This paper summarizes the background of the Pathfinder Project, In-Space Assembly, and Construction activity for fiscal year 1989. Work is presented on high strength mechanical truss joints and the definition of typical large components that might be required for assembly on-orbit and use on interplanetary space missions. Several mechanical joints were designed, and the most promising early design is presented in detail. The primary design drivers were the ability for robot assembly, the correction of up to a + or - 0.020 inch axial misalignment, and an axial load in the vicinity of + or - 100,000 lb. The most promising joint uses axisymmetric grooves to correct the misalignment and to transfer the load in a smooth path.

  3. Optimized Fock space in the large N limit of quartic interactions in matrix models

    NASA Astrophysics Data System (ADS)

    Hynek, Mariusz

    2016-05-01

    We consider the problem of quantization of the bosonic membrane via the large N limit of its matrix regularizations HN in Fock space. We prove that there exists a choice of the Fock space frequency such that HN can be written as a sum of a non-interacting Hamiltonian H0,N and the original normal ordered quartic potential. Using this decomposition we obtain upper and lower bounds for the ground state energy in the planar limit, we study a perturbative expansion about the spectrum of H0,N, and show that the spectral gap remains finite at N = ∞ at least up to the second order. We also apply the method to the U (N)-invariant anharmonic oscillator, and demonstrate that our bounds agree with the exact result of Brezin et al.

  4. ATLAST-9.2m: a Large-Aperture Deployable Space Telescope

    NASA Technical Reports Server (NTRS)

    Oergerle, William; Feinberg, Lee D.; Purves, Lloyd R.; Hyde, T. Tupper; Thronson, Harley A.; Townsend, Jacqueline A.; Postman, Marc; Bolear, Matthew R.; Budinoff, Jason G.; Dean, Bruce H.; Clampin, Mark C.; Ebbets, Dennis C.; Gong, Qian; Gull, Theodore R.; Howard, Joseph M.; Jones, Andrew L.; Lyon, Richard G.; Pasquale, Bert A.; Perrygo, Charles; Smith, Jeffrey S.; Thompson, Patrick L.; Woodgate, Bruce E.

    2010-01-01

    We present results of a study of a deployable version of the Advanced Technology Large-Aperture Space Telescope (ATLAST), designed to operate in a Sun-Earth L2 orbit. The primary mirror of the segmented 9.2-meter aperture has 36 hexagonal 1.315 m (flat to flat) glass mirrors. The architecture and folding of the telescope is similar to JWST, allowing it to fit into the 6.5 m fairing of a modest upgrade to the Delta-IV Heavy version of the Evolved Expendable Launch Vehicle (EELV). We discuss the overall observatory design, optical design, instruments, stray light, wavefront sensing and control, pointing and thermal control, and in-space servicing options.

  5. Radiometer requirements for Earth-observation systems using large space antennas

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr.; Harrington, R. F.

    1983-01-01

    Requirements are defined for Earth observation microwave radiometry for the decade of the 1990's by using large space antenna (LSA) systems with apertures in the range from 50 to 200 m. General Earth observation needs, specific measurement requirements, orbit mission guidelines and constraints, and general radiometer requirements are defined. General Earth observation needs are derived from NASA's basic space science program. Specific measurands include soil moisture, sea surface temperature, salinity, water roughness, ice boundaries, and water pollutants. Measurements are required with spatial resolution from 10 to 1 km and with temporal resolution from 3 days to 1 day. The primary orbit altitude and inclination ranges are 450 to 2200 km and 60 to 98 deg, respectively. Contiguous large scale coverage of several land and ocean areas over the globe dictates large (several hundred kilometers) swaths. Radiometer measurements are made in the bandwidth range from 1 to 37 GHz, preferably with dual polarization radiometers with a minimum of 90 percent beam efficiency. Reflector surface, root mean square deviation tolerances are in the wavelength range from 1/30 to 1/100.

  6. Efficient development and processing of thermal math models of very large space truss structures

    NASA Technical Reports Server (NTRS)

    Warren, Andrew H.; Arelt, Joseph E.; Lalicata, Anthony L.

    1993-01-01

    As the spacecraft moves along the orbit, the truss members are subjected to direct and reflected solar, albedo and planetary infra-red (IR) heating rates, as well as IR heating and shadowing from other spacecraft components. This is a transient process with continuously changing heating loads and the shadowing effects. The resulting nonuniform temperature distribution may cause nonuniform thermal expansion, deflection and stress in the truss elements, truss warping and thermal distortions. There are three challenges in the thermal-structural analysis of the large truss structures. The first is the development of the thermal and structural math models, the second - model processing, and the third - the data transfer between the models. All three tasks require considerable time and computer resources to be done because of a very large number of components involved. To address these challenges a series of techniques of automated thermal math modeling and efficient processing of very large space truss structures were developed. In the process the finite element and finite difference methods are interfaced. A very substantial reduction of the quantity of computations was achieved while assuring a desired accuracy of the results. The techniques are illustrated on the thermal analysis of a segment of the Space Station main truss.

  7. 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, Charbel; Downer, J. D.; Chiou, J. G.; Belvin, W. K.

    1989-01-01

    The deployment, assembly and mission-oriented maneuvering of space structures in orbit will trigger large motions of flexible, truss-type structures. In addition, the presence of on-board controls both for attitude stabilization and specified vibration tolerance requirements may further complicate the dynamic behavior of the orbiting structures. Because of safety and cost considerations, the dynamic response of the combined structural and control systems must be predicted reliably. This need can only be met through the development of reliable and efficient simulation capabilities, since there is general agreement that on-orbit experiments should be limited because of cost, time and facility constraints. The long-term objective of this research effort is to develop a next-generation computer simulator for the dynamics and control of large space structures. The simulator will be based on integrating four research thrusts: a new multibody dynamics formulation methodology, modeling capabilities in long/slender truss-beam components with realistic joints, efficient computational procedures that can be implemented either in sequential or concurrent computers, and prototype simulation modules that can be easily processed into a modern large-scale engineering software system such as the NASA/Computational Structural Mechanics (CSM) testbed.

  8. Large Format Si:As IBC Array Performance for NGST and Future IR Space Telescope Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Johnson, Roy; Love, Peter; Lum, Nancy; McKelvey, Mark; McCreight, Craig; McMurray, Robert, Jr.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A mid-IR (5-30micrometer) instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. A space platform's greatly reduced thermal backgrounds (compared to airborne or ground-based platforms), allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. The previous generation's largest, in sensitive IR detectors at these wavelengths are 256x256 pixel Si:As Impurity Band Conduction (IBC) devices built by Raytheon Infrared Operations (RIO) for the Space Infrared Telescope Facility/Infrared Array Camera (SIRTF)/(IRAC) instrument. RIO has successfully enhanced these devices, increasing the pixel count by a factor of 16 while matching or exceeding SIRTF/IRAC device performance. NASA-ARC in collaboration with RIO has tested the first high performance large format (1024x 1024) Si:As IBC arrays for low background applications, such as for the middle instrument on Next Generation Space Telescope (NGST) and future IR Explorer missions. These hybrid devices consist of radiation hard SIRTF/IRAC-type Si:As IBC material mated to a readout multiplexer that has been specially processed for operation at low cryogenic temperatures (below 10K), yielding high device sensitivity over a wavelength range of 5-28 micrometers. We present laboratory testing results from these benchmark, devices. Continued development in this technology is essential for conducting large-area surveys of the local and early universe through observation and for complementing future missions such as NGST, Terrestrial Planet Finder (TPF), and Focal Plane Instruments and Requirement Science Team (FIRST).

  9. Packaging of large-area individually addressable micromirror arrays for the next generation space telescope

    NASA Astrophysics Data System (ADS)

    Lu, GuoQuan; Calata, J.; Wen, S.; Dutta, Sanghamitra B.; Zheng, Yun; Stahl, C.; Shu, Peter K.

    2002-04-01

    One of NASA's challenging projects for advancing the exploration of space is the development and deployment of the Next Generation Space Telescope (NGST) for superseding the existing Hubble Space Telescope. The NGST will be equipped with several camera/spectrometer systems including a 0.6 to 5 micron Multi-Object-Spectrometer. To selectively direct light rays from different regions of space into the spectrometer, an option is to use individually addressable micro-electro-mechanical-mirror arrays serving as the slit mask for the spectrometer. The NASA team at Goddard Space Flight Center has designed an integrated micro-mirror array/CMOS driver chip that can meet the system requirements. The fabrication and testing of prototype chips have yielded promising results. To build the entire MEMS- based slit mask, a design requires accurate placement and alignment of four large (at least 9 cm X 9 cm) pieces of the integrated chips in a 2X2 mosaic pattern. In addition, the mask will have to function at temperatures below 40 K. These requirements pose a serious challenge to the packaging of these integrated MEMS chips. In this paper, we discuss a concept for attaching and aligning the large- area MEMS chips into the 2X2 mask and interconnecting it to the rest of the system. The concept makes use of the flip-chip technology to bump-bond the large chips onto a silicon substrate such that the concern for global thermo- mechanical stresses due to mismatched coefficients of thermal expansion between chip and substrate is eliminated. It also makes use of the restoring force of the solder bumps during reflow to self-align the chips. A critical experiment involving the use of 'mechanical' chips with two-dimensional arrays of bonding pads was carried out to evaluate the feasibility of the packaging concept. Preliminary results indicate that the chips can be attached to form a closely packed mosaic pattern with a relative tilt angle between the chips to less than 0.05 degree, which is

  10. Large-size deployable construction heated by solar irradiation in free space

    NASA Astrophysics Data System (ADS)

    Pestrenina, Irena; Kondyurin, Alexey; Pestrenin, Valery; Kashin, Nickolay; Naymushin, Alexey

    Large-size deployable construction in free space with subsequent direct curing was invented more than fifteen years ago (Briskman et al., 1997 and Kondyurin, 1998). It caused a lot of scientific problems, one of which is a possibility to use the solar energy for initiation of the curing reaction. This paper is devoted to investigate the curing process under sun irradiation during a space flight in Earth orbits. A rotation of the construction is considered. This motion can provide an optimal temperature distribution in the construction that is required for the polymerization reaction. The cylindrical construction of 80 m length with two hemispherical ends of 10 m radius is considered. The wall of the construction of 10 mm carbon fibers/epoxy matrix composite is irradiated by heat flux from the sun and radiates heat from the external surface by the Stefan- Boltzmann law. A stage of polymerization reaction is calculated as a function of temperature/time based on the laboratory experiments with certified composite materials for space exploitation. The curing kinetics of the composite is calculated for different inclination Low Earth Orbits (300 km altitude) and Geostationary Earth Orbit (40000 km altitude). The results show that • the curing process depends strongly on the Earth orbit and the rotation of the construction; • the optimal flight orbit and rotation can be found to provide the thermal regime that is sufficient for the complete curing of the considered construction. The study is supported by RFBR grant № 12-08-00970-a. 1. Briskman V., A.Kondyurin, K.Kostarev, V.Leontyev, M.Levkovich, A.Mashinsky, G.Nechitailo, T.Yudina, Polymerization in microgravity as a new process in space technology, Paper No IAA-97-IAA.12.1.07, 48th International Astronautical Congress, October 6-10, 1997, Turin Italy. 2. Kondyurin A.V., Building the shells of large space stations by the polymerisation of epoxy composites in open space, Int. Polymer Sci. and Technol., v.25, N4

  11. Stability of large DC power systems using switching converters, with application to the international space station

    NASA Technical Reports Server (NTRS)

    Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.

    1996-01-01

    As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin

  12. The Silicon Tracker Readout Electronics of the Gamma-ray Large Area Space Telescope

    SciTech Connect

    Baldini, Luca; Brez, Alessandro; Himel, Thomas; Hirayama, Masaharu; Johnson, R.P.; Kroeger, Wilko; Latronico, Luca; Minuti, Massimo; Nelson, David; Rando, Riccardo; Sadrozinski, H.F.-W.; Sgro, Carmelo; Spandre, Gloria; Spencer, E.N.; Sugizaki, Mutsumi; Tajima, Hiro; Cohen-Tanugi, Johann; Ziegler, Marcus; /Pisa U. /INFN, Pisa /SLAC /Maryland U. /UC, Santa Cruz /Padua U. /INFN, Padua

    2006-02-27

    A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884,736 36-cm strips using only 160 W of power, and it achieves close to 100% detection efficiency with noise occupancy sufficiently low to allow it to self trigger. The design of the readout system is described, and results are presented from ground-based testing of the completed detector system.

  13. Integrated Analysis Capability pilot computer program. [large space structures and data management

    NASA Technical Reports Server (NTRS)

    Vos, R. G.

    1981-01-01

    An integrated analysis capability (IAC) computer software package was developed for the design analysis and performance evaluation of large space systems. The IAC aids the user in coupling the required technical disciplines (initially structures, thermal and controls), providing analysis solution paths which reveal critical interactive effects in order to study loads, stability and mission performance. Existing technical software modules, having a wide existing user community, are combined with the interface software to bridge between the different technologies and mathematical modeling techniques. The package is supported by executive, data management and interactive graphics software, with primary development within the superminicomputer environment.

  14. Near minimum-time maneuvers of large space structures using parameter optimization

    NASA Technical Reports Server (NTRS)

    Carter, M. T.; Vadali, S. R.; Singh, T.

    1993-01-01

    Near minimum-time attitude maneuvers for large, inherently-flexible space structures with finite fuel supplies are investigated. The open loop maneuver is determined with the Sequential Quadratic Programming (SQP) algorithm, which optimizes a bang-off-bang control parameter set for the given maneuver. Torque smoothing is used to prevent discontinuities in the control which would excite the flexible structure. Additional system dynamics such as thruster inefficiency, spring forces and pressure leaks are identified from preliminary experiments on the ASTREX test article.

  15. Control of large space structures: Status report on achievements and current problems

    NASA Technical Reports Server (NTRS)

    Lyons, M. G.; Aubrun, J. N.

    1983-01-01

    The objectives, state-of-the-art, and problems of large space structures control are outlined. The general objectives range from basic deployment and maneuvering, where some vibration modes may be suppressed, to disturbance rejection for very high performance imaging applications. The controls selected generally must produce some combination of eigenvalue/eigenvector and loads modification in order to achieve the mission objectives. An experiment illustrating the dynamic control of a suspended circular plate is described. Analysis methods used in system modelling, signal processing, and process control and monitoring are discussed. Sensor and actuator performance are assessed.

  16. Characteristics and performance of the ESTEC large space simulator cryogenic system

    NASA Technical Reports Server (NTRS)

    Amlinger, H.; Bosma, S. J.

    1986-01-01

    The final concept and performance characteristics of the Large Space Simulator (LSS) at ESTEC, The Netherlands are discussed. The LSS cryogenics system has proven its operational capabilities under simulated heat load conditions and provides sufficient margin for future elevated requirements. The acceptance test proved that nominal operating pressures can be lower than the design parameters, providing increased system safety and reliability. The ease of access for repair and the incorporated redundancy will limit system downtime. Finally, the system design resulted in a low consumption of LN sub 2, which is an important factor in keeping the operational costs at a low level.

  17. Concept for a power system controller for large space electrical power systems

    NASA Technical Reports Server (NTRS)

    Lollar, L. F.; Lanier, J. R., Jr.; Graves, J. R.

    1981-01-01

    The development of technology for a fail-operatonal power system controller (PSC) utilizing microprocessor technology for managing the distribution and power processor subsystems of a large multi-kW space electrical power system is discussed. The specific functions which must be performed by the PSC, the best microprocessor available to do the job, and the feasibility, cost savings, and applications of a PSC were determined. A limited function breadboard version of a PSC was developed to demonstrate the concept and potential cost savings.

  18. The effects of localized damping on structural response. [of the large space telescope

    NASA Technical Reports Server (NTRS)

    Merchant, D. H.; Gates, R. M.; Ice, M. W.; Vanderlinden, J. W.

    1975-01-01

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

  19. Generalized parity relations for large space structures with uncertain parameters. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Dutilloy, J. R.

    1986-01-01

    The generalized parity relations method is a technique that can be used to detect sensor and actuator failures on a large space structure. A model of a grid structure was used to evaluate the performance of these relations. It shows their relative sensitivity to modeling errors. A method using sensor outputs and actuator inputs is required for the design of the generalized parity relations. Three different estimators are studied. The last estimator can generate relations optimized for the detection of a particular failure which are interesting when the level of sensor noise is high.

  20. Technology for large space systems: A special bibliography with indexes (supplement 05)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This bibliography lists 298 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1981 and June 30, 1981. Its purpose is to provide helpful, information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments.

  1. Technology for large space systems: A special bibliography with indexes (supplement 06)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    This bibliography lists 220 reports, articles and other documents introduced into the NASA scientific and technical information system between July 1, 1981 and December 31, 1981. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments.

  2. Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Arnold, William; Bevan, Ryan M.; Smith, W. Scott.; Kirk, Charles S.; Postman, Mark

    2013-01-01

    An advanced large aperture UV/optical UVO space telescope is required for the next generation of astrophysics and exoplanet science. The science requirements of proposed exoplanet and astrophysics missions were used to determine the encircled energy, point spread function stability and thermal environment requirements. These requirements then determine the optical wavefront specification for potential telescope assemblies which can fit inside current and planned launch vehicles. The optical wavefront specification becomes the top level of the error budget that is split into various sources that control the structural, thermal and optical design.

  3. Cryogenic Design of the Deep Space Network Large Array Low-Noise Amplifier System

    NASA Astrophysics Data System (ADS)

    Britcliffe, M. J.; Hanson, T. R.; Franco, M. M.

    2004-05-01

    This article describes the cryogenic design and performance of a prototype low-noise amplifier (LNA) system for the Deep Space Network (DSN) Large Array task. The system is used to cool a dual-frequency feed system equipped with high-electron mobility transistor (HEMT) low-noise amplifiers and the associated support electronics. The LNA/feed system operates at a temperature under 18 K. The system is designed to be manufactured at minimum cost. The design considerations, including the cryocooler to be used, vacuum system, microwave interconnects, mechanical components, and radiation shielding, are discussed.

  4. 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.

  5. Optimization studies in the support design for the Large Space Telescope.

    NASA Technical Reports Server (NTRS)

    Cella, A.; Maser, K.; Soosaar, K.

    1973-01-01

    A two-stage computer-oriented process is described to design the optimum mirror supports for the NASA Large Space Telescope. Using an element model for the mirror, a set of support displacements is determined so as to minimize the rms optical surface disturbances with respect to a best-fit surface. The second stage uses the STRUDL II-STOP finite element optimization system (a branch and bound approach) to obtain a minimum weight design for the support structure subject to the displacement constraints.

  6. Technology for large space systems: A special bibliography with indexes (supplement 02)

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This bibliography lists 258 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1979 and December 31, 1979. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments.

  7. Deployable antenna technology development for the Large Space Systems Technology program

    NASA Technical Reports Server (NTRS)

    Freeland, R. E.; Campbell, T. G.

    1979-01-01

    The critical technologies associated with the development of deployable reflector antenna technology for the LSST program will be derived from NASA mission models and the subsequent requirements will be related to the classes of missions involved. The approach formulated for the development of reflector technology is based on the development of specific reflector concepts that have been identified as leading candidates for future applications. The development approach will be augmented by supporting technology disciplines such as controls, materials, electromagnetic analysis, as well as the capability of analytically predicting the overall performance of the large space system.

  8. Multiple Boundary Condition Tests (MBCT) for verification of large space structures

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Kuo, C. P.; Glaser, R. J.

    1986-01-01

    The Multiple Boundary Condition Tests (MBCT) approach is evaluated and recent modifications are described. For the application of MBCT, 12 different boundary conditions are selected and the results of applying MBCT in conjunction with a nonlinear formulation are indicated schematically. It is concluded that the nonlinear formulation enhances the ability to implement the MBCT test approach on large space structures which cannot be ground tested without the artificial boundary conditions incorporated in MBCT. In addition, it leads to significant improvements in the convergence to the correct solution.

  9. 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.

  10. A flat array large telescope concept for use on the moon, earth, and in space

    NASA Technical Reports Server (NTRS)

    Woodgate, Bruce E.

    1991-01-01

    An astronomical optical telescope concept is described which can provide very large collecting areas, of order 1000 sq m. This is an order of magnitude larger than the new generation of telescopes now being designed and built. Multiple gimballed flat mirrors direct the beams from a celestial source into a single telescope of the same aperture as each flat mirror. Multiple images of the same source are formed at the telescope focal plane. A beam combiner collects these images and superimposes them into a single image, onto a detector or spectrograph aperture. This telescope could be used on the earth, the moon, or in space.

  11. Bone tissue phantoms for optical flowmeters at large interoptode spacing generated by 3D-stereolithography

    PubMed Central

    Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo

    2014-01-01

    A bone tissue phantom prototype allowing to test, in general, optical flowmeters at large interoptode spacings, such as laser-Doppler flowmetry or diffuse correlation spectroscopy, has been developed by 3D-stereolithography technique. It has been demonstrated that complex tissue vascular systems of any geometrical shape can be conceived. Absorption coefficient, reduced scattering coefficient and refractive index of the optical phantom have been measured to ensure that the optical parameters reasonably reproduce real human bone tissue in vivo. An experimental demonstration of a possible use of the optical phantom, utilizing a laser-Doppler flowmeter, is also presented. PMID:25136496

  12. Technology for large space systems: A bibliography with indexes (supplement 12)

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A bibliography listing 516 reports, articles and other documents introduced into the NASA scientific and technical information system between July 1, 1984 and December 31, 1984 is presented. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of Large Space System Technology. Subject matter is grouped according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems.

  13. Fabry-Pérot filter cavities for wide-spaced frequency combs with large spectral bandwidth

    NASA Astrophysics Data System (ADS)

    Steinmetz, T.; Wilken, T.; Araujo-Hauck, C.; Holzwarth, R.; Hänsch, T. W.; Udem, T.

    2009-08-01

    We use low-finesse Fabry-Pérot cavities in series to generate frequency combs with a large mode spacing in a way that allows its application to a large optical bandwidth. The attenuation of laser modes closest to the pass bands of the cavity exceeds 70 dB for a filter ratio of m=20 relative to the resonant modes centered within the pass bands. We also identify the best cavity geometry to suppress spurious transmission of higher order transversal modes. Such a thinned out frequency comb can be used to calibrate traditional spectrographs for precision astronomy. In the time domain mode filtering generates a pulse train with a multiplied repetition rate. High-fidelity filtering, as described here, implies small variations of the pulse energies.

  14. An assessment of methods for the control of large space structures

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Oz, H.

    1979-01-01

    Large flexible spacecraft represent highly complex distributed-parameter systems. In theory, a distributed-parameter system possesses an infinite number of degrees of freedom. For practical reasons, however, it must be discretized, which implies truncation. From a structural dynamics point of view, a mathematical model can be made more accurate by retaining an increasing number of degrees of freedom. From a control theory point of view, however, an increasing number of degrees of freedom places severe demands on the reliability of the various control algorithms. There is a difference of at least one order of magnitude between the structural modeling requirements and control theory capability. One of the challenges of large space structures control technology is to bridge this difference.

  15. 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.

  16. Efficient eigenvalue assignment by state and output feedback with applications for large space structures

    NASA Technical Reports Server (NTRS)

    Vannell, Eric C.; Kenny, Sean P.; Maghami, Peiman G.

    1995-01-01

    The erection and deployment of large flexible structures having thousands of degrees of freedom requires controllers based on new techniques of eigenvalue assignment that are computationally stable and more efficient. Scientists at NASA Langley Research Center have developed a novel and efficient algorithm for the eigenvalue assignment of large, time-invariant systems using full-state and output feedback. The objectives of this research were to improve upon the output feedback version of this algorithm, to produce a toolbox of MATLAB functions based on the efficient eigenvalue assignment algorithm, and to experimentally verify the algorithm and software by implementing controllers designed using the MATLAB toolbox on the phase 2 configuration of NASA Langley's controls-structures interaction evolutionary model, a laboratory model used to study space structures. Results from laboratory tests and computer simulations show that effective controllers can be designed using software based on the efficient eigenvalue assignment algorithm.

  17. A large high vacuum, high pumping speed space simulation chamber for electric propulsion

    NASA Technical Reports Server (NTRS)

    Grisnik, Stanley P.; Parkes, James E.

    1994-01-01

    Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

  18. Use of reduced basis technique in the inverse dynamics of large space cranes

    NASA Technical Reports Server (NTRS)

    Das, S. K.; Utku, S.; Wada, B. K.

    1990-01-01

    The inverse dynamics of adaptive structures used as space cranes can prove computationally expensive in the case of large structures, due to the large number of degrees of freedom involved. Consequently, reduced basis techniques (reduction techniques) are frequently used to reduce the problem size to a time manageable level (for possible use in real time control). A reduced basis technique is proposed which is different from, but related to, the path-derivatives reduction technique. A linearly independent set of deflection n-tuples is used, chosen at the beginning of the time range in which it is wished to reduce the equations, in whose subspace it is assumed that the deflection vectors of the unreduced problem will lie (approximately).

  19. Multi body model approach to obtain construction criteria for a large space structure

    NASA Astrophysics Data System (ADS)

    Shigehara, M.; Shigedomi, Y.

    Such natural environmental torques as the gravity gradient could substantially influence the attitude behavior of a large space structure, especially in a low Earth orbit. This paper has tried to introduce the basic criteria for constructing a large structure in low-orbit environment, by using the Solar Power Satellite as a model. The criteria can be derived from the static stability map from the rigid body equations and the dynamic behavior from the multi body equations. The multi-body octopus type equations of motion has been introduced to examine transient behaviors during construction. Specifically, inertia matrix change including unsymmetrical configuration change, construction speed and internal momentum change are considered. These results from the transient behavior studies are included, in a general level, in a set of construction criteria.

  20. Multiple boundary condition testing error analysis. [for large flexible space structures

    NASA Technical Reports Server (NTRS)

    Glaser, R. J.; Kuo, C. P.; Wada, B. K.

    1989-01-01

    Techniques for interpreting data from multiple-boundary-condition (MBC) ground tests of large space structures are developed analytically and demonstrated. The use of MBC testing to validate structures too large to stand alone on the ground is explained; the generalized least-squares mass and stiffness curve-fitting methods typically applied to MBC test data are reviewed; and a detailed error analysis is performed. Consideration is given to sensitivity coefficients, covariance-matrix theory, the correspondence between test and analysis modes, constraints and step sizes, convergence criteria, and factor-analysis theory. Numerical results for a simple beam problem are presented in tables and briefly characterized. The improved error-updating capabilities of MBC testing are confirmed, and it is concluded that reasonably accurate results can be obtained using a diagonal covariance matrix.

  1. 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

  2. Large Scale Refrigeration Plant for Ground Testing the James Webb Telescope at NASA Johnson Space Center

    NASA Astrophysics Data System (ADS)

    Arnold, P.; Decker, Lutz; Howe, D.; Urbin, J.; Homan, Jonathan; Reis, Carl; Creel, J.; Ganni, V.; Knudsen, P.; Sidi-Yekhlef, A.

    2010-04-01

    The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox will provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle-Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project.

  3. The Lagrangian-space Effective Field Theory of large scale structures

    SciTech Connect

    Porto, Rafael A.; Zaldarriaga, Matias; Senatore, Leonardo E-mail: senatore@stanford.edu

    2014-05-01

    We introduce a Lagrangian-space Effective Field Theory (LEFT) formalism for the study of cosmological large scale structures. Unlike the previous Eulerian-space construction, it is naturally formulated as an effective field theory of extended objects in Lagrangian space. In LEFT the resulting finite size effects are described using a multipole expansion parameterized by a set of time dependent coefficients and organized in powers of the ratio of the wavenumber of interest k over the non-linear scale k{sub NL}. The multipoles encode the effects of the short distance modes on the long-wavelength universe and absorb UV divergences when present. There are no IR divergences in LEFT. Some of the parameters that control the perturbative approach are not assumed to be small and can be automatically resummed. We present an illustrative one-loop calculation for a power law universe. We describe the dynamics both at the level of the equations of motion and through an action formalism.

  4. Induced emission of radiation from a large space-station-like structure in the ionosphere

    NASA Technical Reports Server (NTRS)

    Hastings, D. E.; Wang, J.

    1989-01-01

    Large conducting structures in the ionosphere may have currents flowing through them which close in the ionospheric plasma. These currents can arise either from current leakage from an onboard power distribution system or by being induced by the motional electric field. Associated with these currents will be broadband electromagnetic radiation in the Alfven and lower hybrid bands. The radiation impedance of this electromagnetic radiation is explored for a structure of space-station-like dimensions as a function of the geometry of the structure and the composition of the ionic environment. It is shown that modification of the collecting area of the structure and environment can be used to minimize the radiation impedance. For a space station, the radiated power will at most be of the order of watts, which does not represent a significant power loss. However, the radiation field will give rise to a substantial pollution of the electromagnetic spectrum in the vicinity of the space station. Design choices to minimize this interference are suggested.

  5. LARGE SCALE REFRIGERATION PLANT FOR GROUND TESTING THE JAMES WEBB TELESCOPE AT NASA JOHNSON SPACE CENTER

    SciTech Connect

    P. Arnold, Lutz Decker, D. Howe, J. Urbin, Jonathan Homan, Carl Reis, J. Creel, V. Ganni, P. Knudsen, A. Sidi-Yekhlef

    2010-04-01

    The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox will provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle—Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project.

  6. In-flight aberrations corrections for large space telescopes using active optics

    NASA Astrophysics Data System (ADS)

    Laslandes, M.; Ferrari, M.; Hugot, E.; Lemaitre, G.

    2010-07-01

    The need for both high quality images and light structures is a constant concern in the conception of space telescopes. The goal here is to determine how an active optics system could be embarked on a satellite in order to correct the wave front deformations of the optical train. The optical aberrations appearing in a space environment are due to mirrors' deformations, with three main origins: the thermal variations, the weightlessness in space with respect to the Assemblage, Integration and Testing (AIT) conditions on ground and the use of large weightlighted primary mirrors. We are developing a model of deformable mirror as minimalist as possible, especially in term of number of actuators, which is able to correct the first Zernike polynomials in the specified range of amplitude and precision. Flight constraints as weight, volume and power consumption have to be considered. Firstly, such a system is designed according to the equations from the elasticity theory: we determine the geometrical and mechanical characteristics of the mirror, the location of the forces to be applied and the way to apply them. The concept is validated with a Finite Element Analysis (FEA), allowing optimizing the system by taking into account parameters absent from the theory. At the end of the program the mirror will be realized and characterized in a representative optical configuration.

  7. 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.

  8. Overview of Small and Large-Scale Space Solar Power Concepts

    NASA Technical Reports Server (NTRS)

    Potter, Seth; Henley, Mark; Howell, Joe; Carrington, Connie; Fikes, John

    2006-01-01

    An overview of space solar power studies performed at the Boeing Company under contract with NASA will be presented. The major concepts to be presented are: 1. Power Plug in Orbit: this is a spacecraft that collects solar energy and distributes it to users in space using directed radio frequency or optical energy. Our concept uses solar arrays having the same dimensions as ISS arrays, but are assumed to be more efficient. If radiofrequency wavelengths are used, it will necessitate that the receiving satellite be equipped with a rectifying antenna (rectenna). For optical wavelengths, the solar arrays on the receiving satellite will collect the power. 2. Mars Clipper I Power Explorer: this is a solar electric Mars transfer vehicle to support human missions. A near-term precursor could be a high-power radar mapping spacecraft with self-transport capability. Advanced solar electric power systems and electric propulsion technology constitute viable elements for conducting human Mars missions that are roughly comparable in performance to similar missions utilizing alternative high thrust systems, with the one exception being their inability to achieve short Earth-Mars trip times. 3. Alternative Architectures: this task involves investigating alternatives to the traditional solar power satellite (SPS) to supply commercial power from space for use on Earth. Four concepts were studied: two using photovoltaic power generation, and two using solar dynamic power generation, with microwave and laser power transmission alternatives considered for each. All four architectures use geostationary orbit. 4. Cryogenic Propellant Depot in Earth Orbit: this concept uses large solar arrays (producing perhaps 600 kW) to electrolyze water launched from Earth, liquefy the resulting hydrogen and oxygen gases, and store them until needed by spacecraft. 5. Beam-Powered Lunar Polar Rover: a lunar rover powered by a microwave or laser beam can explore permanently shadowed craters near the lunar

  9. A New Large Vibration Test Facility Concept for the James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Ross, Brian P.; Johnson, Eric L.; Hoksbergen, Joel; Lund, Doug

    2014-01-01

    The James Webb Space Telescope consists of three main components, the Integrated Science Instrument Module (ISIM) Element, the Optical Telescope Element (OTE), and the Spacecraft Element. The ISIM and OTE are being assembled at the National Aeronautics and Space Administration's Goddard Spaceflight Center (GSFC). The combined OTE and ISIM Elements, called OTIS, will undergo sine vibration testing before leaving Goddard. OTIS is the largest payload ever tested at Goddard and the existing GSFC vibration facilities are incapable of performing a sine vibration test of the OTIS payload. As a result, a new large vibration test facility is being designed. The new facility will consist of a vertical system with a guided head expander and a horizontal system with a hydrostatic slip table. The project is currently in the final design phase with installation to begin in early 2015 and the facility is expected to be operational by late 2015. This paper will describe the unique requirements for a new large vibration test facility and present the selected final design concepts.

  10. Large eddy simulation study of spanwise spacing effects on secondary flows in turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Aliakbarimiyanmahaleh, Mohammad; Anderson, William

    2015-11-01

    The structure of turbulent flow over a complex topography composed of streamwise-aligned rows of cones with varying spanwise spacing, s is studied with large-eddy simulation (LES). Similar to the experimental study of Vanderwel and Ganapathisubramani, 2015: J. Fluid Mech., we investigate the relationship between secondary flow and s, for 0 . 25 <= s / δ <= 5 . For cases with s / δ > 2 , domain-scale rollers freely exist. These had previously been called ``turbulent secondary flows'' (Willingham et al., 2014: Phys. Fluids; Barros and Christensen, 2014: J. Fluid Mech.; Anderson et al., 2015: J. Fluid Mech.), but closer inspection of the statistics indicates these are a turbulent tertiary flow: they only remain ``anchored'' to the conical roughness elements for s / δ > 2 . For s / δ < 2 , turbulent tertiary flows are prevented from occupying the domain by virtue of proximity to adjacent, counter-rotating tertiary flows. Turbulent secondary flows are associated with the conical roughness elements. These turbulent secondary flows emanate from individual conical topographic elements and set the roughness sublayer depth. The turbulent secondary flows remain intact for large and small spacing. For s / δ < 1 , a mean tertiary flow is not present. This work was supported by the Air Force Office of Sci. Research, Young Inv. Program (PM: Dr. R. Ponnoppan and Ms. E. Montomery) under Grant # FA9550-14-1-0394. Computational resources were provided by the Texas Adv. Comp. Center at the Univ. of Texas.

  11. Adaptive combinatorial design to explore large experimental spaces: approach and validation.

    PubMed

    Lejay, L V; Shasha, D E; Palenchar, P M; Kouranov, A Y; Cruikshank, A A; Chou, M F; Coruzzi, G M

    2004-12-01

    Systems biology requires mathematical tools not only to analyse large genomic datasets, but also to explore large experimental spaces in a systematic yet economical way. We demonstrate that two-factor combinatorial design (CD), shown to be useful in software testing, can be used to design a small set of experiments that would allow biologists to explore larger experimental spaces. Further, the results of an initial set of experiments can be used to seed further 'Adaptive' CD experimental designs. As a proof of principle, we demonstrate the usefulness of this Adaptive CD approach by analysing data from the effects of six binary inputs on the regulation of genes in the N-assimilation pathway of Arabidopsis. This CD approach identified the more important regulatory signals previously discovered by traditional experiments using far fewer experiments, and also identified examples of input interactions previously unknown. Tests using simulated data show that Adaptive CD suffers from fewer false positives than traditional experimental designs in determining decisive inputs, and succeeds far more often than traditional or random experimental designs in determining when genes are regulated by input interactions. We conclude that Adaptive CD offers an economical framework for discovering dominant inputs and interactions that affect different aspects of genomic outputs and organismal responses. PMID:17051692

  12. Semi-active damping of large space truss structures using friction joints

    NASA Astrophysics Data System (ADS)

    Gaul, Lothar; Albrecht, Hans; Wirnitzer, Jan

    2002-11-01

    The low structural damping of large space structures and the stringent positioning requirements in missions demand effective vibration suppression. The semi-active approach at hand is based on friction damping due to interfacial slip in semi-active joints which can be controlled by varying the normal pressure in the contact area using a piezo-stack actuator. This paper focuses on the modeling, identification and model reduction of a large space structure with semi-active joints. For the purpose of model identification and model reduction, the nonlinear friction forces transmitted in the joints are considered as external forces acting on the linear tress structure. Experimental Modal Analysis results are used to update the FE model of the truss structure and the parameters of the nonlinear friction model are identified from measured responses of an isolated joint. The model of the linear subsystem is reduced by a combination of balanced reduction and matching moments method. The modal truncation is based on controllability and observability gramians. To improve the fidelity locations conventional connections are replaced by adaptive joints, each with a local feedback controller for the adaptation of the normal force. Simulation results of a 10-bay truss structure with semi-active joints show the potential of the present approach.

  13. 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.

  14. GLAST: Exploring Nature's Highest Energy Processes with the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Digel, Seth; Myers, J. D.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) is an international and multi-agency space mission that will study the cosmos in the energy range 10 keV-300 GeV. Several successful exploratory missions in gamma-ray astronomy led to the Energetic Gamma Ray Experiment Telescope (EGRET) instrument on the Compton Gamma Ray Observatory (CGRO). Launched in 1991, EGRET made the first complete survey of the sky in the 30 MeV-10 GeV range. EGRET showed the high-energy gamma-ray sky to be surprisingly dynamic and diverse, with sources ranging from the sun and moon to massive black holes at large redshifts. Most of the gamma-ray sources detected by EGRET remain unidentified. In light of the discoveries with EGRET, the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope vastly more capable than instruments flown previously, as well as a secondary instrument to augment the study of gamma-ray bursts. The main instrument, the Large Area Telescope (LAT), will have superior area, angular resolution, field of view, and deadtime that together will provide a factor of 30 or more advance in sensitivity, as well as provide capability for study of transient phenomena. The GLAST Burst Monitor (GBM) will have a field of view several times larger than the LAT and will provide spectral coverage of gamma-ray bursts that extends from the lower limit of the LAT down to 10 keV. The basic parameters of the GBM are compared to those of the Burst and Transient Source Experiment (BATSE) instrument on CGRO in Table 1-2. With the LAT and GBM, GLAST will be a flexible observatory for investigating the great range of astrophysical phenomena best studied in high-energy gamma rays. NASA plans to launch GLAST in late 2005.

  15. Active suspension design for a Large Space Structure ground test facility

    NASA Technical Reports Server (NTRS)

    Lange, Thomas J. H.; Schlegel, Clemens

    1993-01-01

    The expected future high performance requirements for Large Space Structures (LSS) enforce technology innovations such as active vibration damping techniques e.g., by means of structure sensors and actuators. The implementation of new technologies like that requires an interactive and integrated structural and control design with an increased effort in hardware validation by ground testing. During the technology development phase generic system tests will be most important covering verification and validation aspects up to the preparation and definition of relevant space experiments. For many applications using advanced designs it is deemed necessary to improve existing testing technology by further reducing disturbances and gravity coupling effects while maintaining high performance reliability. A key issue in this context is the improvement of suspension techniques. The ideal ground test facility satisfying these requirements completely will never be found. The highest degree of reliability will always be obtained by passive suspension methods taking into account severe performance limitations such as non-zero rigid body modes, restriction of degrees of freedom of motion and frequency response limitations. Passive compensation mechanisms, e.g., zero-spring-rate mechanisms, either require large moving masses or they are limited with respect to low-frequency performance by friction, stiction or other non-linear effects. With active suspensions these limitations can be removed to a large extent thereby increasing the range of applications. Despite an additional complexity which is associated with a potential risk in reliability their development is considered promising due to the amazing improvement of real-time control technology which is still continuing.

  16. Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Soummer, Remi; Sivramakrishnan, Annand; Macintosh, Bruce; Guyon, Olivier; Krist, John; Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Kirk, Charles; Arnold, William

    2013-01-01

    ASTRO2010 Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. AMTD is the start of a multiyear effort to develop, demonstrate and mature critical technologies to TRL-6 by 2018 so that a viable flight mission can be proposed to the 2020 Decadal Review. AMTD builds on the state of art (SOA) defined by over 30 years of monolithic & segmented ground & space-telescope mirror technology to mature six key technologies: (1) Large-Aperture, Low Areal Density, High Stiffness Mirror Substrates: Both (4 to 8 m) monolithic and (8 to 16 m) segmented primary mirrors require larger, thicker, and stiffer substrates. (2) Support System: Large-aperture mirrors require large support systems to ensure that they survive launch and deploy on orbit in a stress-free and undistorted shape. (3) Mid/High Spatial Frequency Figure Error: Very smooth mirror is critical for producing high-quality point spread function (PSF) for high contrast imaging. (4) Segment Edges: The quality of segment edges impacts PSF for high-contrast imaging applications, contributes to stray light noise, and affects total collecting aperture. (5) Segment to Segment Gap Phasing: Segment phasing is critical for producing high-quality temporally-stable PSF. (6) Integrated Model Validation: On-orbit performance is driven by mechanical & thermal stability. Compliance cannot be 100% tested, but relies on modeling. AMTD is pursuing multiple design paths to provide the science community with options to enable either large aperture monolithic or segmented mirrors with clear engineering metrics traceable to science requirements.

  17. 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.

  18. Space use of African wild dogs in relation to other large carnivores.

    PubMed

    Darnell, Angela M; Graf, Jan A; Somers, Michael J; Slotow, Rob; Szykman Gunther, Micaela

    2014-01-01

    Interaction among species through competition is a principle process structuring ecological communities, affecting behavior, distribution, and ultimately the population dynamics of species. High competition among large African carnivores, associated with extensive diet overlap, manifests in interactions between subordinate African wild dogs (Lycaon pictus) and dominant lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Using locations of large carnivores in Hluhluwe-iMfolozi Park, South Africa, we found different responses from wild dogs to their two main competitors. Wild dogs avoided lions, particularly during denning, through a combination of spatial and temporal avoidance. However, wild dogs did not exhibit spatial or temporal avoidance of spotted hyenas, likely because wild dog pack sizes were large enough to adequately defend their kills. Understanding that larger carnivores affect the movements and space use of other carnivores is important for managing current small and fragmented carnivore populations, especially as reintroductions and translocations are essential tools used for the survival of endangered species, as with African wild dogs. PMID:24896638

  19. Control design challenges of large space systems and spacecraft control laboratory experiment (SCOLE)

    NASA Technical Reports Server (NTRS)

    Lin, Jiguan Gene

    1987-01-01

    The quick suppression of the structural vibrations excited by bang-bang (BB) type time-optional slew maneuvers via modal-dashpot design of velocity output feedback control was investigated. Simulation studies were conducted, and modal dashpots were designed for the SCOLE flexible body dynamics. A two-stage approach was proposed for rapid slewing and precision pointing/retargeting of large, flexible space systems: (1) slew the whole system like a rigid body in a minimum time under specified limits on the control moments and forces, and (2) damp out the excited structural vibrations afterwards. This approach was found promising. High-power modal/dashpots can suppress very large vibrations, and can add a desirable amount of active damping to modeled modes. Unmodeled modes can also receive some concomitant active damping, as a benefit of spillover. Results also show that not all BB type rapid pointing maneuvers will excite large structural vibrations. When properly selected small forces (e.g., vernier thrusters) are used to complete the specified slew maneuver in the shortest time, even BB-type maneuvers will excite only small vibrations (e.g., 0.3 ft peak deflection for a 130 ft beam).

  20. Space Use of African Wild Dogs in Relation to Other Large Carnivores

    PubMed Central

    Darnell, Angela M.; Graf, Jan A.; Somers, Michael J.; Slotow, Rob; Szykman Gunther, Micaela

    2014-01-01

    Interaction among species through competition is a principle process structuring ecological communities, affecting behavior, distribution, and ultimately the population dynamics of species. High competition among large African carnivores, associated with extensive diet overlap, manifests in interactions between subordinate African wild dogs (Lycaon pictus) and dominant lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Using locations of large carnivores in Hluhluwe-iMfolozi Park, South Africa, we found different responses from wild dogs to their two main competitors. Wild dogs avoided lions, particularly during denning, through a combination of spatial and temporal avoidance. However, wild dogs did not exhibit spatial or temporal avoidance of spotted hyenas, likely because wild dog pack sizes were large enough to adequately defend their kills. Understanding that larger carnivores affect the movements and space use of other carnivores is important for managing current small and fragmented carnivore populations, especially as reintroductions and translocations are essential tools used for the survival of endangered species, as with African wild dogs. PMID:24896638

  1. Space Situational Awareness of Large Numbers of Payloads From a Single Deployment

    NASA Astrophysics Data System (ADS)

    Segerman, A.; Byers, J.; Emmert, J.; Nicholas, A.

    2014-09-01

    The nearly simultaneous deployment of a large number of payloads from a single vehicle presents a new challenge for space object catalog maintenance and space situational awareness (SSA). Following two cubesat deployments last November, it took five weeks to catalog the resulting 64 orbits. The upcoming Kicksat mission will present an even greater SSA challenge, with its deployment of 128 chip-sized picosats. Although all of these deployments are in short-lived orbits, future deployments will inevitably occur at higher altitudes, with a longer term threat of collision with active spacecraft. With such deployments, individual scientific payload operators require rapid precise knowledge of their satellites' locations. Following the first November launch, the cataloguing did not initially associate a payload with each orbit, leaving this to the satellite operators. For short duration missions, the time required to identify an experiment's specific orbit may easily be a large fraction of the spacecraft's lifetime. For a Kicksat-type deployment, present tracking cannot collect enough observations to catalog each small object. The current approach is to treat the chip cloud as a single catalog object. However, the cloud dissipates into multiple subclouds and, ultimately, tiny groups of untrackable chips. One response to this challenge may be to mandate installation of a transponder on each spacecraft. Directional transponder transmission detections could be used as angle observations for orbit cataloguing. Of course, such an approach would only be employable with cooperative spacecraft. In other cases, a probabilistic association approach may be useful, with the goal being to establish the probability of an element being at a given point in space. This would permit more reliable assessment of the probability of collision of active spacecraft with any cloud element. This paper surveys the cataloguing challenges presented by large scale deployments of small spacecraft

  2. Design and fabrication of a large vertical travel silicon inchworm microactuator for advanced segmented silicon space telescope (ASSIST)

    NASA Technical Reports Server (NTRS)

    Yang, E.; Dekany, R.; Padin, S.

    2003-01-01

    The goal of this research is to develop inchworm motor systems capable of simultaneously providing nanometer resolution, high stiffness, large output force, long travel range, and compactness for ultraprecision positioning applications in space.

  3. The Development of Large Inflatable Antenna for Deep-Space Communications

    NASA Technical Reports Server (NTRS)

    Huang, John; Fang, Houfei; Lovick, Richard; Lou, Michael

    2004-01-01

    NASA/JPL's deep-space exploration program has been placing emphasis on reducing the mass and stowage volume of its spacecraft's high-gain and large-aperture antennas. To achieve these goals, the concept of deployable flat reflectarray antenna using an inflatable/thin-membrane structure was introduced at JPL several years ago. A reflectarray is a flat array antenna space-fed by a low-gain feed located at its focal point in a fashion similar to that of a parabolic reflector. The ref1ectarray's elements, using microstrip technology, can be printed onto a flat thin-membrane surface and are each uniquely designed to compensate for the different phase delays due to different path lengths from the feed. Although the reflectarray suffers from limited bandwidth (typically < 10%), it offers a more reliably deployed and maintained flat "natural" surface. A recent hardware development at JPL has demonstrated that a 0.2mm rms surface tolerance (l/50th of a wavelength) was achieved on a 3-meter Ka-band inflatable reflectarray. Another recent development, to combat the reflectarray's narrow band characteristic, demonstrated that dual-band performance, such as X- and Ka-bands, with an aperture efficiency of above 50 percent is achievable by the reflectarray antenna. To mechanically deploy the antenna, the reflectarray's thin membrane aperture surface is supported, tensioned and deployed by an inflatable tubular structure. There are several critical elements and challenging issues associated with the inflatable tube structure. First, the inflatable tube must be made rigidizable so that, once the tube is fully deployed in space, it rigidizes itself and the inflation system is no longer needed. In addition, if the tube is penetrated by small space debris, the tube will maintain its rigidity and not cause deformation to the antenna structure. To support large apertures (e.g. 10m or beyond) without causing any buckling to the small-diameter inflatable tube during vibration, the tube

  4. Optimizing nutrient channel spacing and revisiting TGF-beta in large engineered cartilage constructs.

    PubMed

    Cigan, Alexander D; Nims, Robert J; Vunjak-Novakovic, Gordana; Hung, Clark T; Ateshian, Gerard A

    2016-07-01

    Cartilage tissue engineering is a promising approach to treat osteoarthritis. However, current techniques produce tissues too small for clinical relevance. Increasingly close-packed channels have helped overcome nutrient transport limitations in centimeter-sized chondrocyte-agarose constructs, yet optimal channel spacings to recapitulate native cartilage compositional and mechanical properties in constructs this large have not been identified. Transient active TGF-β treatment consistently reproduces native compressive Young׳s modulus (EY) and glycosaminoglycan (GAG) content in constructs, but standard dosages of 10ng/mL exacerbate matrix heterogeneity. To ultimately produce articular layer-sized constructs, we must first optimize channel spacing and investigate the role of TGF-β in the utility of channels. We cultured ∅10mm constructs with 0, 12, 19, or 27 nutrient channels (∅1mm) for 6-8 weeks with 0, 1, or 10ng/mL TGF-β; subsequently we analyzed them mechanically, biochemically, and histologically. Constructs with 12 or 19 channels grew the most favorably, reaching EY=344±113kPa and GAG and collagen contents of 10.8±1.2% and 2.2±0.2% of construct wet weight, respectively. Constructs with 27 channels had significantly less deposited GAG than other groups. Channeled constructs given 1 or 10ng/mL TGF-β developed similar properties. Without TGF-β, constructs with 0 or 12 channels exhibited properties that were indistinguishable, and lower than TGF-β-supplemented constructs. Taken together, these results emphasize that nutrient channels are effective only in the presence of TGF-β, and indicate that spacings equivalent to 12 channels in ∅10mm constructs can be employed in articular-layer-sized constructs with reduced dosages of TGF-β. PMID:27255605

  5. The ESA Large Space Simulator Mechanical Ground Support Equipment for Spacecraft Testing

    NASA Technical Reports Server (NTRS)

    Hagelschuer, Dirk; Messing, Rene; Westera, Roel

    2008-01-01

    Environmental test facilities are not suitable in any case to comply with special or complex test requirements without modifications. Dedicated upgrades of the test facility and their subsystems with respect to the test requirements and specifications are often necessary. The Flight Model of the Planck Space Telescope was tested in the Large Space Simulator (LSS) of the ESTEC Test Centre. Main goals of the test were the verification of the deformation of the Telescope during thermal vacuum conditions at different temperature levels and the validation of the Thermal Model. The deformations of the telescope have been traced by two Videogrammetry canisters. In order to provide different view positions with respect to the PLANCK Telescope it was necessary to rotate the specimen by +/- 180deg. In addition very stringent requirements for the low temperature level of the thermal environment has lead to a comprehensive test set-up which was divided in four main elements: Dedicated support structure for the Videogrammetry canisters providing several DoF for adjustment. Structure to support three Infrared panels around the specimen. MLI curtain to cover the LSS 8m auxiliary chamber opening. System providing LN2 supply for the rotating PLANCK telescope cold panel. The design, manufacturing and integration of the necessary mechanical ground support to install for instance the canisters and to ensure the 180 rotation of the telescope under cold and high vacuum conditions was an extensive and important part of the entire test program. This paper will concentrate on the design issues, the implementation and verification of the MGSE provided for the Planck Space Telescope FM Videogrammetry Test in the LSS and the troubleshooting caused by a failure during the first rotation under cold conditions.

  6. NASA Goddard Space Flight Center, on Behalf of the Fermi Large Area Telescope Collaboration

    NASA Technical Reports Server (NTRS)

    Thompson, David J.

    2010-01-01

    Because high-energy gamma rays can be produced by processes that also produce neutrinos, the gamma-ray survey of the sky by the Fermi (Gamma-ray Space Telescope offers a view of potential targets for neutrino observations. Gamma-ray bursts. Active Galactic Nuclei, and supernova remnants are all sites where hadronic, neutrino-producing interactions are plausible. Pulsars, pulsar wind nebulae, and binary sources are all phenomena that reveal leptonic particle acceleration through their gamma-ray emission. While important to gamma-ray astrophysics, such sources are of less interest to neutrino studies. This talk will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT)on the Fermi spacecraft.

  7. Large-Scale Hollow Retroreflectors for Lunar Laser Ranging at Goddard Space Flight Center

    NASA Astrophysics Data System (ADS)

    Preston, Alix M.

    2012-05-01

    Laser ranging to the retroreflector arrays placed on the lunar surface by the Apollo astronauts and the Soviet Luna missions have dramatically increased our understanding of gravitational physics along with Earth and Moon geophysics, geodesy, and dynamics. Although the precision of the range measurements has historically been limited by the ground station capabilities, advances in the APOLLO instrument at the Apache Point facility in New Mexico is beginning to be limited by errors associated with the lunar arrays. We report here on efforts at Goddard Space Flight Center to develop the next generation of lunar retroreflectors. We will describe a new facility that is being used to design, assemble, and test large-scale hollow retroreflectors. We will also describe results from investigations into various bonding techniques used to assemble the open corner cubes and mirror coatings that have dust mitigation properties.

  8. Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Baldini, L.; Uchiyama, Y.

    2011-01-01

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of Galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TcV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a Galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

  9. Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Thompson, David J.; Baldini, L.; Uchiyama, Y.

    2012-01-01

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TeV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

  10. Low thrust chemical propulsion for orbit transfer of large space structures

    NASA Technical Reports Server (NTRS)

    Shoji, J. M.

    1981-01-01

    For transporting Large Space Structures (LSS) from Low Earth Orbit (LEO) to Geosynchronous Equatorial Orbit (GEO), a variety of low thrust engine cycles have been evaluated for oxygen/hydrogen and oxygen/hydrocarbon propellants. The engine cycles included conventional propellant turbine drives (gas generator, expander, and staged-combustion cycles), turboalternator/electric motor pump drive, and fuel-cell/electric motor pump drive, as well as pressure-fed engines. The thrust chamber cooling limits and the engine cycle limits were established for a range of thrust levels. The candidate engine cycles were analyzed, screened, rated, and two engine cycle/configurations were selected for preliminary engine design. Preliminary engine designs for these two engines were formulated and engine design layouts prepared and parametric engine data generated.

  11. Results from computer program for analyzing scattered light suppression systems for large space telescope

    NASA Technical Reports Server (NTRS)

    Tifft, W. G.; Fannin, B. B.

    1974-01-01

    A computer program was developed which has the ability to analyze the performance of most light suppression systems so as to predict the amount of scattered light which will reach the image plane for various conditions of unwanted light input from the sun, earth, or moon. This program was used to analyze three different configurations of the large space telescope (LST): an LST with a truncated sunshield, an LST with an extended cylindrical sunshield, and an LST with a conical sunshield which is tilted upwards. The computer program gives the user detailed information as to the paths taken by the unwanted stray light to reach the image plane, and pinpoints those portions of the light suppression system which contribute most of the stray light, so that areas requiring improvements are evident. Certain design guide lines were formulated for any light suppression system selected for the LST, and one which meets these requirements (the tilted sunshade) is described in detail.

  12. Studying the High Energy Gamma Ray Sky with Gamma Ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Kamae, T.; Ohsugi, T.; Thompson, D. J.; Watanabe, K.

    1998-01-01

    Building on the success of the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the Gamma Ray Large Area Space Telescope (GLAST) will make a major step in the study of such subjects as blazars, gamma Ray bursts, the search for dark matter, supernova remnants, pulsars, diffuse radiation, and unidentified high energy sources. The instrument will be built on new and mature detector technologies such as silicon strip detectors, low-power low-noise LSI, and a multilevel data acquisition system. GLAST is in the research and development phase, and one full tower (of 25 total) is now being built in collaborating institutes. The prototype tower will be tested thoroughly at Stanford Linear Accelerator Center (SLAC) in the fall of 1999.

  13. Imaging Extra-Solar Planets with an Ultra-Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Taylor, Charles R.

    1998-01-01

    NASA's Origins Program is directed toward two main goals: Imaging of galactic evolution in the early universe, and searching for planets orbiting nearby stars. The Next-Generation Space Telescope (NGST), operating at low temperature with an 8-m aperture, is well designed to meet the first goal. The goal of imaging planets orbiting nearby stars is more problematic. One line of investigation has been the ULTIMA concept (Ultra-Large Telescope, Integrated Missions in Astronomy). In this report, I will lay out the resolution requirements for telescopes to achieve the imaging of extrasolar planets, and describe a modeling tool created to investigate the requirements for imaging a planet when it is very near a much brighter star.

  14. Large-Scale Hollow Retroreflectors for Lunar Laser Ranging at Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Preston, Alix

    2012-01-01

    Laser ranging to the retroreflector arrays placed on the lunar surface by the Apollo astronauts and the Soviet Luna missions have dramatically increased our understanding of gravitational physics along with Earth and Moon geophysics, geodesy, and dynamics. Although the precision of the range measurements has historically been limited by the ground station capabilities, advances in the APOLLO instrument at the Apache Point facility in New Mexico is beginning to be limited by errors associated with the lunar arrays. We report here on efforts at Goddard Space Flight Center to develop the next generation of lunar retroreflectors. We will describe a new facility that is being used to design, assemble, and test large-scale hollow retroreflectors. We will also describe results from investigations into various bonding techniques used to assemble the open comer cubes and mirror coatings that have dust mitigation properties.

  15. Study of electrical and chemical propulsion systems for auxiliary propulsion of large space systems, volume 2

    NASA Technical Reports Server (NTRS)

    Smith, W. W.

    1981-01-01

    The five major tasks of the program are reported. Task 1 is a literature search followed by selection and definition of seven generic spacecraft classes. Task 2 covers the determination and description of important disturbance effects. Task 3 applies the disturbances to the generic spacecraft and adds maneuver and stationkeeping functions to define total auxiliary propulsion systems requirements for control. The important auxiliary propulsion system characteristics are identified and sensitivities to control functions and large space system characteristics determined. In Task 4, these sensitivities are quantified and the optimum auxiliary propulsion system characteristics determined. Task 5 compares the desired characteristics with those available for both electrical and chemical auxiliary propulsion systems to identify the directions technology advances should take.

  16. Large Advanced Space Systems (LASS) computer-aided design program additions

    NASA Technical Reports Server (NTRS)

    Farrell, C. E.

    1982-01-01

    The LSS preliminary and conceptual design requires extensive iteractive analysis because of the effects of structural, thermal, and control intercoupling. A computer aided design program that will permit integrating and interfacing of required large space system (LSS) analyses is discussed. The primary objective of this program is the implementation of modeling techniques and analysis algorithms that permit interactive design and tradeoff studies of LSS concepts. Eight software modules were added to the program. The existing rigid body controls module was modified to include solar pressure effects. The new model generator modules and appendage synthesizer module are integrated (interfaced) to permit interactive definition and generation of LSS concepts. The mass properties module permits interactive specification of discrete masses and their locations. The other modules permit interactive analysis of orbital transfer requirements, antenna primary beam n, and attitude control requirements.

  17. Thermo/structural design considerations to achieve the Large Space Telescope line-of-sight requirements

    NASA Technical Reports Server (NTRS)

    Tenerelli, D. J.

    1975-01-01

    The Large Space Telescope (LST) which is scheduled for launch in 1982, is a long-life, precision-pointing, earth-orbiting satellite requiring a structural system that provides high dimensional stability, minimum thermal distortion, and minimum response to onboard dynamic environments (e.g., reaction wheels). The results of a detailed thermostructural finite element computer analysis show that the telescope structure, even though fabricated from a material with a zero coefficient of thermal expansion, must be isolated from the external structure by a three-point support (flex joints or spherical bearings will accomplish this). Other thermo/structural analysis of the metering structure showed that second-order deformations have a significant effect on the alignment of the primary and secondary mirrors.

  18. Adaptive Filtering for Large Space Structures: A Closed-Form Solution

    NASA Technical Reports Server (NTRS)

    Rauch, H. E.; Schaechter, D. B.

    1985-01-01

    In a previous paper Schaechter proposes using an extended Kalman filter to estimate adaptively the (slowly varying) frequencies and damping ratios of a large space structure. The time varying gains for estimating the frequencies and damping ratios can be determined in closed form so it is not necessary to integrate the matrix Riccati equations. After certain approximations, the time varying adaptive gain can be written as the product of a constant matrix times a matrix derived from the components of the estimated state vector. This is an important savings of computer resources and allows the adaptive filter to be implemented with approximately the same effort as the nonadaptive filter. The success of this new approach for adaptive filtering was demonstrated using synthetic data from a two mode system.

  19. Spatial, High-Accuracy, Positioning-Encoding Sensor (SHAPES) for large space system control applications

    NASA Technical Reports Server (NTRS)

    Mclauchlan, J. M.

    1982-01-01

    The Spatial, High-Accuracy, Position-Encoding Sensor is a controls sensor suitable for the determination of the static shape and vibrational motion of large space structures and similar systems and for the determination of position and velocity in rendezvous and docking. It uses a combination of electro-optical techniques to measure the three-dimensional coordinates distributed over the structure at reading rates high compared to the rates at which the coordinates are changing. The technical approach is that of measuring the distance to and the direction of points on the structure from a single sensor head. Many points can be measured simultaneously from a single head without significantly increasing the complexity of the system.

  20. A multilevel control system for the large space telescope. [numerical analysis/optimal control

    NASA Technical Reports Server (NTRS)

    Siljak, D. D.; Sundareshan, S. K.; Vukcevic, M. B.

    1975-01-01

    A multilevel scheme was proposed for control of Large Space Telescope (LST) modeled by a three-axis-six-order nonlinear equation. Local controllers were used on the subsystem level to stabilize motions corresponding to the three axes. Global controllers were applied to reduce (and sometimes nullify) the interactions among the subsystems. A multilevel optimization method was developed whereby local quadratic optimizations were performed on the subsystem level, and global control was again used to reduce (nullify) the effect of interactions. The multilevel stabilization and optimization methods are presented as general tools for design and then used in the design of the LST Control System. The methods are entirely computerized, so that they can accommodate higher order LST models with both conceptual and numerical advantages over standard straightforward design techniques.

  1. Aerodynamic characteristics of a large aircraft to transport space shuttle orbiter or other external payloads

    NASA Technical Reports Server (NTRS)

    Paulson, J. W., Jr.

    1975-01-01

    Wind tunnel tests were conducted in the Langley V/STOL tunnel to determine the aerodynamic characteristics of a large transport aircraft designed to carry the space shuttle orbiter or orbiter booster tank. Results indicate that the transport, with or without payloads, is statically stable, the longitudinal static margins being rather excessive. Elevator power is sufficient to trim the transport up to stall except when the orbiter is mounted close to the wing. Maximum lift-drag ratios at wind tunnel Reynolds numbers vary from 12 to 14 depending on model configuration. Tests were conducted at Reynolds numbers from 1.21 x 1 million to 1.49 x 1 million with angle of attack from -2 deg to 20 deg and angle of sideslip from -5 deg to 5 deg.

  2. Structural evaluation of candidate designs for the large space telescope primary mirror

    NASA Technical Reports Server (NTRS)

    Soosaar, K.; Grin, R.; Furey, M.; Hamilton, J.

    1975-01-01

    Structural performance analyses were conducted on two candidate designs (Itek and Perkin-Elmer designs) for the large space telescope three-meter mirror. The mirror designs and the finite-element models used in the analyses evaluation are described. The results of the structural analyses for several different types of loading are presented in tabular and graphic forms. Several additional analyses are also reported: the evaluation of a mirror design concept proposed by the Boeing Co., a study of the global effects of local cell plate deflections, and an investigation of the fracture mechanics problems likely to occur with Cervit and ULE. Flexibility matrices were obtained for the Itek and Perkin-Elmer mirrors to be used in active figure control studies. Summary, conclusions, and recommendations are included.

  3. Controller design and parameter identifiability studies for a large space antenna

    NASA Technical Reports Server (NTRS)

    Joshi, S. M.

    1985-01-01

    The problem of control systems synthesis and parameter identifiability are considered for a large, space-based antenna. Two methods are considered for control system synthesis, the first of which uses torque actuators and collocated attitude and rate sensors, and the second method is based on the linear-quadratic-Gaussian (LQG) control theory. The predicted performance obtained by computing variances of pointing, surface and feed misalignment errors in the presence of sensor noise indicates that the LQG-based controller yields superior results. Since controller design requires the knowledge of the system parameters, the identifiability of the structural parameters is investigated by obtaining Cramer-Rao lower bounds. The modal frequencies are found to have the best identifiability, followed by damping ratios, and mode-slopes.

  4. Automated assembly of large space structures using an expert system executive

    NASA Technical Reports Server (NTRS)

    Allen, Cheryl L.

    1993-01-01

    NASA LaRC has developed a unique testbed for investigating the practical problems associated with the assembly of large space structures using robotic manipulators. The testbed is an interdisciplinary effort which considers the full spectrum of assembly problems from the design of mechanisms to the development of software. This paper will describe the automated structures assembly testbed and its operation, detail the expert system executive and its development, and discuss the planned system evolution. Emphasis will be placed on the expert system development of the program executive. The executive program must be capable of directing and reliably performing complex assembly tasks with the flexibility to recover from realistic system errors. By employing an expert system, information pertaining to the operation of the system was encapsulated concisely within a knowledge base. This lead to a substantial reduction in code, increased flexibility, eased software upgrades, and realized a savings in software maintenance costs.

  5. An expert system executive for automated assembly of large space truss structures

    NASA Technical Reports Server (NTRS)

    Allen, Cheryl L.

    1993-01-01

    Langley Research Center developed a unique test bed for investigating the practical problems associated with the assembly of large space truss structures using robotic manipulators. The test bed is the result of an interdisciplinary effort that encompasses the full spectrum of assembly problems - from the design of mechanisms to the development of software. The automated structures assembly test bed and its operation are described, the expert system executive and its development are detailed, and the planned system evolution is discussed. Emphasis is on the expert system implementation of the program executive. The executive program must direct and reliably perform complex assembly tasks with the flexibility to recover from realistic system errors. The employment of an expert system permits information that pertains to the operation of the system to be encapsulated concisely within a knowledge base. This consolidation substantially reduced code, increased flexibility, eased software upgrades, and realized a savings in software maintenance costs.

  6. An ultrahigh-accuracy body pointing system for the Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Rybak, S. C.; Mayo, R. A.; Lieberman, S. I.; Hartter, L. L.

    1974-01-01

    The Large Space Telescope (LST) program is aimed at placing a three-meter diffraction-limited telescope in a 270-nm orbit to perform astronomical observations that are not possible with earth-based telescopes. A complex simulation model is described which was developed to determine whether the stringent pointing stability requirements could be met. The model (programmed on a hybrid computer) included detailed dynamic representation of control moment gyros (CMGs) and reaction wheels (RWs), including their noise characteristics; dynamic sensor representation (including noise); shockmounts for the CMG actuators; detailed representation of an image motion compensation system; and a detailed flexible body vehicle model. Stability and performance studies based on the simulation model showed that the body pointing system will meet LST requirements in the presence of CMG vibrational disturbances and sensor noise. The recommended system consists of three orthogonally mounted RWs for primary short-term control, and a cluster of CMG actuators for continuous RW desaturation and vehicle maneuvering.

  7. Modal test and analysis: Multiple tests concept for improved validation of large space structure mathematical models

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Kuo, C-P.; Glaser, R. J.

    1986-01-01

    For the structural dynamic analysis of large space structures, the technology in structural synthesis and the development of structural analysis software have increased the capability to predict the dynamic characteristics of the structural system. The various subsystems which comprise the system are represented by various displacement functions; the displacement functions are then combined to represent the total structure. Experience has indicated that even when subsystem mathematical models are verified by test, the mathematical representations of the total system are often in error because the mathematical model of the structural elements which are significant when loads are applied at the interconnection points are not adequately verified by test. A multiple test concept, based upon the Multiple Boundary Condition Test (MBCT), is presented which will increase the accuracy of the system mathematical model by improving the subsystem test and test/analysis correlation procedure.

  8. GESE: A Small UV Space Telescope to Conduct a Large Spectroscopic Survey of Z-1 Galaxies

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Gong, Qian; Hull, Tony; Kruk, Jeffrey; Purves, Lloyd

    2013-01-01

    One of the key goals of NASA's astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a space mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at a redshift, z is approximately 1 (look-back time of approximately 8 billion years). GESE is a 1.5-meter space telescope with an ultraviolet (UV) multi-object slit spectrograph that can obtain spectra of hundreds of galaxies per exposure. The spectrograph covers the spectral range, 0.2-0.4 micrometers at a spectral resolving power, R approximately 500. This observed spectral range corresponds to 0.1-0.2 micrometers as emitted by a galaxy at a redshift, z=1. The mission concept takes advantage of two new technological advances: (1) light-weighted, wide-field telescope mirrors, and (2) the Next- Generation MicroShutter Array (NG-MSA) to be used as a slit generator in the multi-object slit spectrograph.

  9. Development of load-dependent Ritz vector method for structural dynamic analysis of large space structures

    NASA Technical Reports Server (NTRS)

    Ricles, James M.

    1990-01-01

    The development and preliminary assessment of a method for dynamic structural analysis based on load-dependent Ritz vectors are presented. The vector basis is orthogonalized with respect to the mass and structural stiffness in order that the equations of motion can be uncoupled and efficient analysis of large space structure performed. A series of computer programs was developed based on the algorithm for generating the orthogonal load-dependent Ritz vectors. Transient dynamic analysis performed on the Space Station Freedom using the software was found to provide solutions that require a smaller number of vectors than the modal analysis method. Error norm based on the participation of the mass distribution of the structure and spatial distribution of structural loading, respectively, were developed in order to provide an indication of vector truncation. These norms are computed before the transient analysis is performed. An assessment of these norms through a convergence study of the structural response was performed. The results from this assessment indicate that the error norms can provide a means of judging the quality of the vector basis and accuracy of the transient dynamic solution.

  10. Real time identification of large space structures. Ph.D. Thesis - MIT

    NASA Technical Reports Server (NTRS)

    Voss, Janice E.

    1987-01-01

    Identification of frequencies, damping ratios, and mode shapes of large space structures (LSSs) are examined in real time. Real time processing allows for quick updates of model processing after a reconfiguration of structural failure. Recursive lattice least squares (RLLS) was selected as the baseline algorithm for the identification. Simulation results on a one dimensional LSS demonstrated that it provides good estimates, was not ill-conditioned in the presence of under-excited modes, allowed activity by a supervisory control system which prevented damage to the LSS or excessive drift, and was capable of real-time processing for typical LSS models. A suboptimal version of RLLS, which is equivalent to simulated parallel processing, was derived. A NASTRAN model of the dual keel U.S. space station was used to demonstrate the input/identification algorithm package in a more realistic simulation. Because the first eight flexible modes were very close together, the identification was much more difficult than in the simple examples. Even so, the model was accurately identified in real time.

  11. Advances in solid state switchgear technology for large space power systems

    NASA Technical Reports Server (NTRS)

    Sundberg, G. R.

    1984-01-01

    High voltage solid state remote power controllers (RPC's) and the required semiconductor power switches to provide baseline technology for large, high power distribution systems in the space station, all electric airplane and other advanced aerospace applications were developed. The RPC's were developed for dc voltages from 28 to 1200 V and ac voltages of 115, 230, and 440 V at frequencies of 400 Hz to 20 kHz. The benefits and operation of solid state RPC's and highlights of several developments to bring the RPC to technology readiness for future aerospace needs are examined. The 28 V dc Space Shuttle units, three RPC types at 120 V dc, two at 270/300 V dc, two at 230 V ac and several high power RPC models at voltages up to 1200 V dc with current ratings up to 100 A are reviewed. New technology programs to develop a new family of (DI)2 semiconductor switches and 20 kHz, 440 V ac RPC's are described.

  12. Hubble Space Telescope Images of Submillimeter Sources: Large Irregular Galaxies at High Redshift

    NASA Astrophysics Data System (ADS)

    Chapman, S. C.; Windhorst, R.; Odewahn, S.; Yan, H.; Conselice, C.

    2003-12-01

    We present new Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) high-resolution optical imaging of a sample of 13 submillimeter luminous galaxies for which the optical emission has been pinpointed either through radio 1.4 GHz or millimeter interferometry. We find a predominance of irregular and complex morphologies in the sample, suggesting that mergers are likely common for submillimeter galaxies. The component separations in these objects are on average a factor 2 larger than in local galaxies with similarly high bolometric luminosities. The sizes and star formation rates of the submillimeter galaxies are consistent with the maximal star formation rate densities of 20 Msolar kpc-2 in local starburst galaxies (Lehnert & Heckman). We derive quantitative morphological information for optical galaxies hosting submillimeter emission: total and isophotal magnitudes, Petrosian radius, effective radius, concentration, aspect ratio, surface brightness, and asymmetry. We compare these morphological indexes with those of other galaxies lying within the same STIS images. Most strikingly, we find ~70% of the submillimeter galaxies to be extraordinarily large and elongated relative to the field population, regardless of optical magnitude. Comparison of the submillimeter galaxy morphologies with those of optically selected galaxies at z~2-3 reveals the submillimeter galaxies to be a morphologically distinct population, with generally larger sizes, higher concentrations, and more prevalent major-merger configurations.

  13. 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

    2016-06-01

    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. PMID:27149080

  14. Thermally-induced bending-torsion coupling vibration of large scale space structures

    NASA Astrophysics Data System (ADS)

    Xue, Ming-De; Duan, Jin; Xiang, Zhi-Hai

    2007-09-01

    In this paper, a finite element scheme is developed to solve the problem of thermally-induced bending-torsion coupling vibration of large scale space structures, which are usually composed of thin-walled beams with open and closed cross-section. A two-noded finite element is proposed to analyze the transient temperature field over the longitudinal and circumferential direction of a beam. Since this temperature element can share the same mesh with the two-noded beam element of Euler-Bernoulli type, a unified finite element scheme is easily formulated to solve the thermal-structural coupling problem. This scheme is characterized with very strong nonlinear formulation, due to the consideration of the thermal radiation and the coupling effect between structural deformations and the incident normal heat flux. Moreover, because the warping is taken into account, not only the thermal axial force and thermal bending moments but also the thermal bi-moment are presented in the formulation. Consequently, the thermally-induced bending-torsion coupling vibration can be simulated. The performance of the proposed computational scheme is illustrated by the analysis of the well-known failure of Hubble space telescope solar arrays. The results reveal that the thermally-induced bending-torsion coupling vibration is obviously presented in that case and could be regarded as a cause of failure.

  15. 8 Meter Advanced Technology Large-Aperture Space Telescope (ATLAST-8m)

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    ATLAST-8m (Advanced Technology Large Aperture Space Telescope) is a proposed 8-meter monolithic UV/optical/NIR space observatory (wavelength range 110 to 2500 nm) to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V heavy lift vehicle. Given its very high angular resolution (15 mas @ 500 nm), sensitivity and performance stability, ATLAST-8m is capable of achieving breakthroughs in a broad range of astrophysics including: Is there life elsewhere in the Galaxy? An 8-meter UVOIR observatory has the performance required to detect habitability (H2O, atmospheric column density) and biosignatures (O2, O3, CH4) in terrestrial exoplanet atmospheres, to reveal the underlying physics that drives star formation, and to trace the complex interactions between dark matter, galaxies, and intergalactic medium. The ATLAST Astrophysics Strategic Mission Concept Study developed a detailed point design for an 8-m monolithic observatory including optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; mass and power budgets; and system cost. The results of which were submitted by invitation to NRC's 2010 Astronomy & Astrophysics Decadal Survey.

  16. Formulation and verification of frequency response system identification techniques for large space structures

    NASA Technical Reports Server (NTRS)

    Mitchell, Jerrel R.; Jones, Victoria L.; Plant, Charles

    1988-01-01

    For the past several years much effort has been given to the development of techniques for designing control systems for large space structures (LSS's). The main objective of these efforts has been to develop a LSS control methodology that produces designs that meet strenuous performance requirements and are robust to model inaccuracies. Unfortunately, performance and robustness are conflicting requirements. Because LSS's can not be fully tested on ground, it has become an accepted fact that the design of LSS control systems to meet performance requirements can not be completed until the LSS is placed on-orbit and tested and an accurate model is extracted from on-orbit test results. Modern MIMO sampled-data frequency response design techniques are viable candidates for designing LSS control systems. First, this paper presents techniques for performing MIMO system identification (ID) from test data. Then, techniques for improving the performance of the system ID process in the presence of noise are presented. Finally, practical utility of the system ID approaches are validated by the presentation of results obtained from application on the LSS Ground Test Facility at Marshall Space Flight Center.

  17. A finite element approach for large motion dynamic analysis of multibody structures in space

    NASA Technical Reports Server (NTRS)

    Chang, Che-Wei

    1989-01-01

    A three-dimensional finite element formulation for modeling the transient dynamics of constrained multibody space sructures with truss-like configurations is presented. Convected coordinate systems are used to define rigid-body motion of individual elements in the system. These systems are located at one end of each element and are oriented such that one axis passes through the other end of the element. Deformation of each element, relative to its convected coordinate system, is defined by cubic flexural shape functions as used in finite element methods of structural analysis. The formulation is oriented toward joint dominated structures and places the generalized coordinates at the joint. A transformation matrix is derived to integrate joint degree-of-freedom into the equations of motion of the element. Based on the derivation, a general-purpose code LATDYN (Large Angle Transient DYNamics) was developed. Two examples are presented to illustrate the application of the code. For the spin-up of a flexible beam, results are compared with existing solutions available in the literature. For the deployment of one bay of a deployable space truss (the Minimast), results are verified by the geometric knowledge of the system and converged solution of a successively refined model.

  18. A large underestimate of the pyrogenic source of formic acid inferred from space-borne measurements.

    NASA Astrophysics Data System (ADS)

    Chaliyakunnel, S.; Millet, D. B.; Wells, K. C.; Cady-Pereira, K.; Shephard, M.

    2015-12-01

    Formic acid (HCOOH) is one of the most abundant carboxylic acids in the atmosphere, and a dominant source of acidity in the global troposphere. Recent work has revealed a major gap in our present understanding of the atmospheric formic acid budget, with observed concentrations much larger than can be reconciled with current estimates of its sources. In this work, we employ new space-based observations from the Tropospheric Emission Spectrometer (TES) satellite instrument with the GEOS-Chem chemical transport model to better quantify the source of atmospheric formic acid from biomass burning, and assess the degree to which this source can help close the large budget gap for this species. The space-based formic acid data reveal a severe model underestimate for HCOOH that is most prominent over tropical biomass burning regions, indicating a major missing source of organic acids from fires. Based on two independent methods for inferring the fractional contribution of fires to the measured HCOOH abundance, we find that the pyrogenic HCOOH:CO enhancement ratio measured by TES (including direct emissions plus secondary production) is 5-10 times higher than current estimates of the direct emission ratio, providing evidence of substantial secondary production of HCOOH in fire plumes. We further show that current models significantly underestimate (by a factor of 2-6) the total primary and secondary source of HCOOH from tropical fires.

  19. Single-field consistency relations of large scale structure part II: resummation and redshift space

    SciTech Connect

    Creminelli, Paolo; Gleyzes, Jérôme; Vernizzi, Filippo; Simonović, Marko E-mail: jerome.gleyzes@cea.fr E-mail: filippo.vernizzi@cea.fr

    2014-02-01

    We generalize the recently derived single-field consistency relations of Large Scale Structure in two directions. First, we treat the effect of the long modes (with momentum q) on the short ones (with momentum k) non-perturbatively, by writing resummed consistency relations which do not require k/q⋅δ{sub q} << 1. These relations do not make any assumptions on the short-scales physics and are extended to include (an arbitrary number of) multiple long modes, internal lines with soft momenta and soft loops. We do several checks of these relations in perturbation theory and we verify that the effect of soft modes always cancels out in equal-time correlators. Second, we write the relations directly in redshift space, without assuming the single-stream approximation: not only the long mode affects the short scales as a homogeneous gravitational field, but it also displaces them by its velocity along the line-of-sight. Redshift space consistency relations still vanish when short modes are taken at equal time: an observation of a signal in the squeezed limit would point towards multifield inflation or a violation of the equivalence principle.

  20. Isn't the space-charge potential in ceria-based solid electrolytes largely overestimated?

    PubMed

    Kim, Sangtae

    2016-07-20

    The effective ionic conductivity of polycrystalline solid electrolytes that conduct oxide ions or protons is known to be markedly below those of the corresponding single crystals due to substantial current obstruction across the grain boundary. Numerous studies have previously demonstrated that the ionic charge carriers deplete in the vicinity of the grain boundary to form a potential barrier at the grain boundary, which further impedes the current across the grain boundary. Hence an accurate estimation of the barrier height is essential to acquire a comprehensive and precise mechanistic picture of the ionic current in solid electrolytes. The values of the potential barrier height, i.e. equivalent to the equilibrium space-charge potential with the opposite sign, in prominent solid electrolytes such as ceria solid solutions are available in the literature and were determined exclusively from the ratio of the resistivity of the grain boundary to that of the crystal interior. Here I present the results clearly demonstrating that the resistivity ratio yields considerable overestimation of the barrier height even in relatively diluted solid solutions of ceria. These results imply that the space charge is unlikely the sole origin of the large current obstruction across the grain boundary in ceria-based solid electrolytes. PMID:27388961

  1. Potential for on-orbit manufacture of large space structures using the pultrusion process

    NASA Technical Reports Server (NTRS)

    Wilson, Maywood L.; Macconochie, Ian O.; Johnson, Gary S.

    1987-01-01

    On-orbit manufacture of lightweight, high-strength, advanced-composite structures using the pultrusion process is proposed. This process is adaptable to a zero-gravity environment by using preimpregnated graphite-fiber reinforcement systems. The reinforcement material is preimpregnated with a high-performance thermoplastic resin at a ground station, is coiled on spools for compact storage, and is transported into Earth orbit. A pultrusion machine is installed in the Shuttle cargo bay from which very long lengths of the desired structure is fabricated on-orbit. Potential structural profiles include rods, angles, channels, hat sections, tubes, honeycomb-cored panels, and T, H, and I beams. A potential pultrudable thermoplastic/graphite composite material is presented as a model for determining the effect on Earth-to-orbit package density of an on-orbit manufacture, the package density is increased by 132 percent, and payload volume requirement is decreased by 56.3 percent. The fabrication method has the potential for on-orbit manufacture of structural members for space platforms, large space antennas, and long tethers.

  2. Observing the Moon at Microwave Frequencies Using a Large-Diameter Deep Space Network Antenna

    NASA Astrophysics Data System (ADS)

    Morabito, David D.; Imbriale, William; Keihm, Stephen

    2008-03-01

    The Moon radiates energy at infrared and microwave wavelengths, in addition to reflecting sunlight at optical wavelengths. As a result, an antenna pointed at or near the Moon will result in an increase in system operating noise temperature, which needs to be accounted for in RF telecommunications, radio science or radiometric link calculations. The NASA Deep Space Network (DSN) may use its large-diameter antennas in future lunar robotic or human missions, and thus it is important to understand the nature of this temperature incre ase as a function of observing frequency, lunar phase, and angular position of the antenna beam on the lunar disk. This paper reports on a comprehensive lunar noise temperature measurement campaign and associated theoretical treatment for a 34-m diameter Deep Space Network antenna observing an extended source such as the Moon. A set of measurements over a wide range of lunar phase angles was acquired at DSS-13, a 34-m diameter beam waveguide antenna (BWG) located at Goldstone, California at 2.3 GHz (S-band), 8.4 GHz (X-band) and 32 GHz (Ka-band). For validation purposes, independent predictions of noise temperature increase were derived using a physical optics characterization of the 34-m diameter antenna gain patterns and Apollo model-based brightness temperature maps of the Moon as input. The model-based predictions of noise temperature increase were compared with the measurements at all three frequencies. In addition, a methodology is presented that relates noise temperature increase due to the Moon to disk-centered or disk-averaged brightness temperature of the Moon at the microwave frequencies of interest. Comparisons were made between the measurements and models in the domain of lunar disk-centered and disk-averaged brightness temperatures. It is anticipated that the measurements and associated theoretical development will be useful in developing telecommunications strategies for future high-rate Ka-band communications where large

  3. Topology optimization-based lightweight primary mirror design of a large-aperture space telescope.

    PubMed

    Liu, Shutian; Hu, Rui; Li, Quhao; Zhou, Ping; Dong, Zhigang; Kang, Renke

    2014-12-10

    For the large-aperture space telescope, the lightweight primary mirror design with a high-quality optical surface is a critical and challenging issue. This work presents a topology optimization-based design procedure for a lightweight primary mirror and a new mirror configuration of a large-aperture space telescope is obtained through the presented design procedure. Inspired by the topology optimization method considering cast constraints, an optimization model for the configuration design of the mirror back is proposed, through which the distribution and the heights of the stiffeners on the mirror back can be optimized simultaneously. For the purpose of minimizing the optical surface deviation due to self-weight and polishing pressure loadings, the objective function is selected as to maximize the mirror structural stiffness, which can be achieved by minimizing the structural compliance. The total mass of the primary mirror is assigned as the constraint. In the application example, results of the optimized design topology for two kinds of mass constraints are presented. Executing the design procedure for specific requirements and postprocessing the topology obtained of the structure, a new mirror configuration with tree-like stiffeners and a multiple-arch back in double directions is proposed. A verification model is constructed to evaluate the design results and the finite element method is used to calculate the displacement of the mirror surface. Then the RMS deviation can be obtained after fitting the deformed surface by Zernike polynomials. The proposed mirror is compared with two classical mirrors in the optical performance, and the comparison results demonstrate the superiority of the new mirror configuration. PMID:25608076

  4. Analysis of Radar and Optical Space Borne Data for Large Scale Topographical Mapping

    NASA Astrophysics Data System (ADS)

    Tampubolon, W.; Reinhardt, W.

    2015-03-01

    Normally, in order to provide high resolution 3 Dimension (3D) geospatial data, large scale topographical mapping needs input from conventional airborne campaigns which are in Indonesia bureaucratically complicated especially during legal administration procedures i.e. security clearance from military/defense ministry. This often causes additional time delays besides technical constraints such as weather and limited aircraft availability for airborne campaigns. Of course the geospatial data quality is an important issue for many applications. The increasing demand of geospatial data nowadays consequently requires high resolution datasets as well as a sufficient level of accuracy. Therefore an integration of different technologies is required in many cases to gain the expected result especially in the context of disaster preparedness and emergency response. Another important issue in this context is the fast delivery of relevant data which is expressed by the term "Rapid Mapping". In this paper we present first results of an on-going research to integrate different data sources like space borne radar and optical platforms. Initially the orthorectification of Very High Resolution Satellite (VHRS) imagery i.e. SPOT-6 has been done as a continuous process to the DEM generation using TerraSAR-X/TanDEM-X data. The role of Ground Control Points (GCPs) from GNSS surveys is mandatory in order to fulfil geometrical accuracy. In addition, this research aims on providing suitable processing algorithm of space borne data for large scale topographical mapping as described in section 3.2. Recently, radar space borne data has been used for the medium scale topographical mapping e.g. for 1:50.000 map scale in Indonesian territories. The goal of this on-going research is to increase the accuracy of remote sensing data by different activities, e.g. the integration of different data sources (optical and radar) or the usage of the GCPs in both, the optical and the radar satellite data

  5. The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

    SciTech Connect

    Atwood, W.B.; Abdo, Aous A.; Ackermann, M.; Anderson, B. Axelsson, M.; Baldini, L.; Ballet, J.; Band, D.L.; Barbiellini, Guido; Bartelt, J.; Bastieri, Denis; Baughman, B.M.; Bechtol, K.; Bederede, D.; Bellardi, F.; Bellazzini, R.; Berenji, B.; Bignami, G.F.; Bisello, D.; Bissaldi, E.; Blandford, R.D.; /more authors..

    2009-05-15

    The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure

  6. R×B drift momentum spectrometer with high resolution and large phase space acceptance.

    PubMed

    Wang, X; Konrad, G; Abele, H

    2013-02-11

    We propose a new type of momentum spectrometer, which uses the R×B drift effect to disperse the charged particles in a uniformly curved magnetic field, and measures the particles with large phase space acceptance and high resolution. This kind of R×B spectrometer is designed for the momentum analyses of the decay electrons and protons in the PERC (Proton and Electron Radiation Channel) beam station, which provides a strong magnetic field to guide the charged particles in the instrument. Instead of eliminating the guiding field, the R×B spectrometer evolves the field gradually to the analysing field, and the charged particles can be adiabatically transported during the dispersion and detection. The drifts of the particles have similar properties as their dispersion in the normal magnetic spectrometer. Besides, the R×B spectrometer is especially ideal for the measurements of particles with low momenta and large incident angles. We present a design of the R×B spectrometer, which can be used in PERC. For the particles with solid angle smaller than 88 msr, the maximum aberration is below 10(-4). The resolution of the momentum spectra can reach 14.4 keV/c, if the particle position measurements have a resolution of 1 mm. PMID:23576831

  7. A Future Large-Aperture UVOIR Space Observatory: Key Technologies and Capabilities

    NASA Technical Reports Server (NTRS)

    Bolcar, Matthew Ryan; Stahle, Carl M.; Balasubramaniam, Kunjithapatham; Clampin, Mark; Feinberg, Lee D.; Mosier, Gary E.; Quijada, Manuel A.; Rauscher, Bernard J.; Redding, David C.; Rioux, Norman M.; Shaklan, Stuart B.; Stahl, H. Philip; Thronson, Harley A.

    2015-01-01

    We present the key technologies and capabilities that will enable a future, large-aperture ultravioletopticalinfrared (UVOIR) space observatory. These include starlight suppression systems, vibration isolation and control systems, lightweight mirror segments, detector systems, and mirror coatings. These capabilities will provide major advances over current and near-future observatories for sensitivity, angular resolution, and starlight suppression. The goals adopted in our study for the starlight suppression system are 10-10 contrast with an inner working angle of 20 milliarcsec and broad bandpass. We estimate that a vibration and isolation control system that achieves a total system vibration isolation of 140 dB for a vibration-isolated mass of 5000 kg is required to achieve the high wavefront error stability needed for exoplanet coronagraphy. Technology challenges for lightweight mirror segments include diffraction-limited optical quality and high wavefront error stability as well as low cost, low mass, and rapid fabrication. Key challenges for the detector systems include visible-blind, high quantum efficiency UV arrays, photon counting visible and NIR arrays for coronagraphic spectroscopy and starlight wavefront sensing and control, and detectors with deep full wells with low persistence and radiation tolerance to enable transit imaging and spectroscopy at all wavelengths. Finally, mirror coatings with high reflectivity ( 90), high uniformity ( 1) and low polarization ( 1) that are scalable to large diameter mirror substrates will be essential for ensuring that both high throughput UV observations and high contrast observations can be performed by the same observatory.

  8. Requirements for a mobile communications satellite system. Part 3: Large space structures measurements study

    NASA Astrophysics Data System (ADS)

    Akle, W.

    1983-03-01

    This study report defines a set of tests and measurements required to characterize the performance of a Large Space System (LSS), and to scale this data to other LSS satellites. Requirements from the Mobile Communication Satellite (MSAT) configurations derived in the parent study were used. MSAT utilizes a large, mesh deployable antenna, and encompasses a significant range of LSS technology issues in the areas of structural/dynamics, control, and performance predictability. In this study, performance requirements were developed for the antenna. Special emphasis was placed on antenna surface accuracy, and pointing stability. Instrumentation and measurement systems, applicable to LSS, were selected from existing or on-going technology developments. Laser ranging and angulation systems, presently in breadboard status, form the backbone of the measurements. Following this, a set of ground, STS, and GEO-operational were investigated. A third scale (15 meter) antenna system as selected for ground characterization followed by STS flight technology development. This selection ensures analytical scaling from ground-to-orbit, and size scaling. Other benefits are cost and ability to perform reasonable ground tests. Detail costing of the various tests and measurement systems were derived and are included in the report.

  9. Requirements for a mobile communications satellite system. Volume 3: Large space structures measurements study

    NASA Technical Reports Server (NTRS)

    Akle, W.

    1983-01-01

    This study report defines a set of tests and measurements required to characterize the performance of a Large Space System (LSS), and to scale this data to other LSS satellites. Requirements from the Mobile Communication Satellite (MSAT) configurations derived in the parent study were used. MSAT utilizes a large, mesh deployable antenna, and encompasses a significant range of LSS technology issues in the areas of structural/dynamics, control, and performance predictability. In this study, performance requirements were developed for the antenna. Special emphasis was placed on antenna surface accuracy, and pointing stability. Instrumentation and measurement systems, applicable to LSS, were selected from existing or on-going technology developments. Laser ranging and angulation systems, presently in breadboard status, form the backbone of the measurements. Following this, a set of ground, STS, and GEO-operational were investigated. A third scale (15 meter) antenna system as selected for ground characterization followed by STS flight technology development. This selection ensures analytical scaling from ground-to-orbit, and size scaling. Other benefits are cost and ability to perform reasonable ground tests. Detail costing of the various tests and measurement systems were derived and are included in the report.

  10. A parameter database for large scientific projects: application to the Gaia space astrometry mission

    NASA Astrophysics Data System (ADS)

    Perryman, Michael; de Bruijne, Jos; Lammers, Uwe

    2008-10-01

    The parallel development of many aspects of a complex space science mission like Gaia, which includes numerous participants in ESA, industrial companies, and a large and active scientific collaboration throughout Europe, makes keeping track of the many design changes, instrument and operational parameters, and numerical values for the data analysis and simulations, a challenging but crucially important problem. A comprehensive, easily-accessible, up-to-date, and definitive compilation of a large range of numerical quantities is required, and the Gaia parameter database has been established to satisfy these needs. The database is a centralised repository containing, besides mathematical, physical, and astronomical constants, many satellite and subsystem design parameters. Version control provides both a ‘live’ version with the most recent parameters, as well as previous ‘reference’ versions of the full database contents. Query results are formatted by default in HTML, while an important feature is that data can also be retrieved as Java, ANSI-C, C++, Ruby, or XML structures for direct inclusion into software codes, such that all collaborating scientists can use the retrieved database parameters and values directly linked to computational routines.

  11. An Overview of Latest Model Reduction and Control Methods of Large Flexible Space Structures

    NASA Technical Reports Server (NTRS)

    Santiago, J. M.; Lange, W. J., Jr.; Jamshidi, M.

    1985-01-01

    The latest trends and theoretical developments involved with the modeling and control of Large Flexible Space Structures (LFSS) are described. The paper addresses first the basic problems, characteristics, and difficulties inherent in modeling and control of LFSS. Major sources of difficulties and errors are the stiffness and damping operators of the dynamic model. Extensions of Linear Quadratic Gaussian (LQG) theory as applied to LFSS are presented, including frequency-shaped cost functionals and perturbation methods. The minimum data/maximum entropy approach which uses a stochastic design model to overcome difficulties found in the LQG-based methods is described. Latest trends in system theory including balanced realization and singular-value analysis are used to determine reduced order controllers and models. Ad hoc methods such as component cost analysis and modal cost analysis are discussed in context with the closed-loop reduction problem of controller order versus performance. The minimum data/maximum entropy approach also addresses controller order versus performance. Those areas of control science and large scale systems that appear to have an important role in understanding and solving LFSS modeling and control are also identified.

  12. Revealing the global map of protein folding space by large-scale simulations

    NASA Astrophysics Data System (ADS)

    Sinner, Claude; Lutz, Benjamin; Verma, Abhinav; Schug, Alexander

    2015-12-01

    The full characterization of protein folding is a remarkable long-standing challenge both for experiment and simulation. Working towards a complete understanding of this process, one needs to cover the full diversity of existing folds and identify the general principles driving the process. Here, we want to understand and quantify the diversity in folding routes for a large and representative set of protein topologies covering the full range from all alpha helical topologies towards beta barrels guided by the key question: Does the majority of the observed routes contribute to the folding process or only a particular route? We identified a set of two-state folders among non-homologous proteins with a sequence length of 40-120 residues. For each of these proteins, we ran native-structure based simulations both with homogeneous and heterogeneous contact potentials. For each protein, we simulated dozens of folding transitions in continuous uninterrupted simulations and constructed a large database of kinetic parameters. We investigate folding routes by tracking the formation of tertiary structure interfaces and discuss whether a single specific route exists for a topology or if all routes are equiprobable. These results permit us to characterize the complete folding space for small proteins in terms of folding barrier ΔG‡, number of routes, and the route specificity RT.

  13. Concepted design of a surface measurement system for large deployable space antennas

    NASA Technical Reports Server (NTRS)

    Neiswander, R. S.

    1982-01-01

    The sensor system is in essence a point design, specifically interfacing with the Harris, Inc., 1000 meter deployable mesh communication antenna. The design can, without large modification, be adapted to other large deployable antennas such as the Lockheed Wrap-rib, the General Dynamics Precision Erectable Truss and the TRW Advanced Sunflower antennas. Measurements are optical displacements. The elements of the system are a central cluster of receivers near the apex of the antenna and active bright targets at the antenna. The cluster defines a single coordinate frame from which all surface positions are referenced. The receivers continuously observe an extended array of sample points located throughout the reflecting surface and its supporting structure. For the Harris antenna, the surface samples are at the mesh gore lines and at the supporting hoop. Output data is in real-time, compatible with on-board processing and active control of antenna figure. Lifetime of the system is at least 10 years continuous operation in space.

  14. Modern sampled-data control theory: Design of the Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Kuo, B. C.; Singh, G.

    1974-01-01

    This investigation was undertaken to determine the effect of varying the sampling period on the dynamic response of the sampled-data Large Space Telescope (LST) system. A range of sampling periods was recommended based on the criterion that self-sustained oscillations are to be avoided in the LST system. The step responses of the LST system were then investigated when various sampling periods are used. For small sampling periods, the dynamic behavior of the sampled-data system is very similar to that of the continuous-data system. When T is large (but less than 0.25 sec) the overshoot of the step response of the sampled-data becomes greater. However, the dynamic behavior of the sampled-data system may be improved by redesigning the controller. It appears that a sampling period as high as 0.1 second is feasible for the LST system. However, it should be noted that the conclusions are obtained with the existing system model. Other practical considerations such as noise, coupling effects and quantization errors, may restrict the sampling period to a lower value.

  15. Time-space Kriging to address the spatiotemporal misalignment in the large datasets

    PubMed Central

    Liang, Dong; Kumar, Naresh

    2013-01-01

    This paper presents a Bayesian hierarchical spatiotemporal method of interpolation, termed as Markov Cube Kriging (MCK). The classical Kriging methods become computationally prohibitive, especially for large datasets due to the O(n3) matrix decomposition. MCK offers novel and computationally efficient solutions to address spatiotemporal misalignment, mismatch in the spatiotemporal scales and missing values across space and time in large spatiotemporal datasets. MCK is flexible in that it allows for non-separable spatiotemporal structure and nonstationary covariance at the hierarchical spatiotemporal scales. Employing MCK we developed estimates of daily concentration of fine particulates matter ≤2.5 μm in aerodynamic diameter (PM2.5) at 2.5 km spatial grid for the Cleveland Metropolitan Statistical Area, 2000 to 2009. Our validation and cross-validation suggest that MCK achieved robust prediction of spatiotemporal random effects and underlying hierarchical and nonstationary spatiotemporal structure in air pollution data. MCK has important implications for environmental epidemiology and environmental sciences for exposure quantification and collocation of data from different sources, available at different spatiotemporal scales. PMID:24039539

  16. Time-space Kriging to address the spatiotemporal misalignment in the large datasets

    NASA Astrophysics Data System (ADS)

    Liang, Dong; Kumar, Naresh

    2013-06-01

    This paper presents a Bayesian hierarchical spatiotemporal method of interpolation, termed as Markov Cube Kriging (MCK). The classical Kriging methods become computationally prohibitive, especially for large datasets due to the O(n3) matrix decomposition. MCK offers novel and computationally efficient solutions to address spatiotemporal misalignment, mismatch in the spatiotemporal scales and missing values across space and time in large spatiotemporal datasets. MCK is flexible in that it allows for non-separable spatiotemporal structure and nonstationary covariance at the hierarchical spatiotemporal scales. Employing MCK we developed estimates of daily concentration of fine particulates matter ≤2.5 μm in aerodynamic diameter (PM2.5) at 2.5 km spatial grid for the Cleveland Metropolitan Statistical Area, 2000 to 2009. Our validation and cross-validation suggest that MCK achieved robust prediction of spatiotemporal random effects and underlying hierarchical and nonstationary spatiotemporal structure in air pollution data. MCK has important implications for environmental epidemiology and environmental sciences for exposure quantification and collocation of data from different sources, available at different spatiotemporal scales.

  17. Large Space Telescopes Using Fresnel Lens for Power Beaming, Astronomy and Sail Missions

    SciTech Connect

    Early, J T

    2002-10-15

    The concept of using Fresnel optics as part of power beaming, astronomy or sail systems has been suggested by several authors. The primary issues for large Fresnel optics are the difficulties in fabricating these structures and deploying them in space and for astronomy missions the extremely narrow frequency range of these optics. In proposals where the telescope is used to transmit narrow frequency laser power, the narrow bandwidth has not been an issue. In applications where the optic is to be used as part of a telescope, only around 10{sup -5} to limited frequency response of a Fresnel optic is addressed by the use of a corrective optic that will broaden the frequency response of the telescope by three or four orders of magnitude. This broadening will dramatically increase the optical power capabilities of the system and will allow some spectroscopy studies over a limited range. Both the fabrication of Fresnel optics as large as five meters and the use of corrector optics for telescopes have been demonstrated at LLNL. For solar and laser sail missions the use of Fresnel amplitude zone plates made of very thin sail material is also discussed.

  18. The Advanced Technology Large-Aperture Space Telescope (ATLAST) Technology Roadmap

    NASA Technical Reports Server (NTRS)

    Stahle, Carl; Balasubramanian, K.; Bolcar, M.; Clampin, M.; Feinberg, L.; Hartman, K.; Mosier, C.; Quijada, M.; Rauscher, B.; Redding, D.; Shaklan, S.; Stahl, P.; Thronson, H.

    2014-01-01

    We present the key technologies and capabilities that will enable a future, large-aperture ultravioletopticalinfrared (UVOIR) space observatory. These include starlight suppression systems, vibration isolation and control systems, lightweight mirror segments, detector systems, and mirror coatings. These capabilities will provide major advances over current and near-future observatories for sensitivity, angular resolution, and starlight suppression. The goals adopted in our study for the starlight suppression system are 10-10 contrast with an inner working angle of 40 milliarcsec and broad bandpass. We estimate that a vibration and isolation control system that achieves a total system vibration isolation of 140 dB for a vibration-isolated mass of 5000 kg is required to achieve the high wavefront error stability needed for exoplanet coronagraphy. Technology challenges for lightweight mirror segments include diffraction-limited optical quality and high wavefront error stability as well as low cost, low mass, and rapid fabrication. Key challenges for the detector systems include visible-blind, high quantum efficiency UV arrays, photon counting visible and NIR arrays for coronagraphic spectroscopy and starlight wavefront sensing and control, and detectors with deep full wells with low persistence and radiation tolerance to enable transit imaging and spectroscopy at all wavelengths. Finally, mirror coatings with high reflectivity ( 90), high uniformity ( 1) and low polarization ( 1) that are scalable to large diameter mirror substrates will be essential for ensuring that both high throughput UV observations and high contrast observations can be performed by the same observatory.

  19. Time-space Kriging to address the spatiotemporal misalignment in the large datasets.

    PubMed

    Liang, Dong; Kumar, Naresh

    2013-06-01

    This paper presents a Bayesian hierarchical spatiotemporal method of interpolation, termed as Markov Cube Kriging (MCK). The classical Kriging methods become computationally prohibitive, especially for large datasets due to the O(n(3)) matrix decomposition. MCK offers novel and computationally efficient solutions to address spatiotemporal misalignment, mismatch in the spatiotemporal scales and missing values across space and time in large spatiotemporal datasets. MCK is flexible in that it allows for non-separable spatiotemporal structure and nonstationary covariance at the hierarchical spatiotemporal scales. Employing MCK we developed estimates of daily concentration of fine particulates matter ≤2.5 μm in aerodynamic diameter (PM2.5) at 2.5 km spatial grid for the Cleveland Metropolitan Statistical Area, 2000 to 2009. Our validation and cross-validation suggest that MCK achieved robust prediction of spatiotemporal random effects and underlying hierarchical and nonstationary spatiotemporal structure in air pollution data. MCK has important implications for environmental epidemiology and environmental sciences for exposure quantification and collocation of data from different sources, available at different spatiotemporal scales. PMID:24039539

  20. Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Engineering Model: Overview

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Godfrey, G.; Williams, S. M.; Grove, J. E.; Mizuno, T.; Sadrozinski, H. F.-W.; Kamae, T.; Ampe, J.; Briber, Stuart; Dann, James; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) is a pair-production high-energy (greater than 20 MeV) gamma-ray telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006, designed to study a wide variety of high-energy astrophysical phenomena. As part of the development effort, the collaboration has built a Balloon Flight Engineering Model (BFEM) for flight on a high-altitude scientific balloon. The BFEM is approximately the size of one of the 16 GLAST-LAT towers and contains all the components of the full instrument: plastic scintillator anticoincidence system (ACD), high-Z foil/Si strip pair-conversion tracker (TKR), CsI hodoscopic calorimeter (CAL), triggering and data acquisition electronics (DAQ), commanding system, power distribution, telemetry, real-time data display, and ground data processing system. The principal goal of the balloon flight was to demonstrate the performance of this instrument configuration under conditions similar to those expected in orbit. Results from a balloon flight from Palestine, Texas, on August 4, 2001, show that the BFEM successfully obtained gamma-ray data in this high-background environment.

  1. 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.

  2. European river flow regimes: assessing space-time dynamics and links to large-scale climate

    NASA Astrophysics Data System (ADS)

    Hannah, D. M.; Kingston, D. G.; Laize, C.; Lavers, D. A.; Wilson, D.

    2011-12-01

    Given heightened concerns about climate change/ variability and human impacts on hydrology, there is a pressing need for research to quantify temporal variability and spatial structure in river flow regimes, and to establish hydroclimatological (climate-flow) associations as a basis for predicting future water stress. This paper draws together findings from studies undertaken at the UK and pan-European scale (using datasets of >100 stations with time series >25 years) and aims: (1) to demonstrate the utility of classification schemes for identifying space-time patterns in river flow regimes and (2) to explore the hydroclimatological relationships between large-scale atmospheric circulation and river flow response. Often, classification is undertaken prior to detailed analysis of large-scale patterns in river flow. In this paper, a suite of novel cluster analysis based methods are presented that identify hydrological regions as well as inter-annual river flow regime variation within regions. Statistical characteristics of the emergent classifications are analysed including geographical expression, teleconnections and presence of time-series trends. Results show that classification provides a useful general organising framework for large-scale hydrological research and facilitates systematic testing of hypotheses about drivers of hydrological variation across wide spatial domains. To investigate climate controls on space-time river flow variation, three methods for characterising atmospheric influences are considered: air-mass types, large-scale climate indices and gridded re-analyses (ECMWF ERA-40). A new air-mass classification for Europe (Spatial Synoptic Classification 2) is presented that classifies daily air-masses. Data are pooled by long-term flow regime regions to assess air-mass - flow regime (shape and magnitude) class associations across Europe; and multiple discriminant function analysis (MDFA) is used to model links between the categorical data. The

  3. Thermal Influence of a Large Green Space on a Hot Urban Environment.

    PubMed

    Sugawara, Hirofumi; Shimizu, Shogo; Takahashi, Hideo; Hagiwara, Shinsuke; Narita, Ken-Ichi; Mikami, Takehiko; Hirano, Tatsuki

    2016-01-01

    City-scale warming is becoming a serious problem in terms of human health. Urban green spaces are expected to act as a countermeasure for urban warming, and therefore better understanding of the micro-climate benefits of urban green is needed. This study quantified the thermal influence of a large green park in Tokyo, Japan on the surrounding urban area by collecting long-term measurements. Apparent variations in the temperature difference between the park and surrounding town were found at both the diurnal and seasonal scales. Advection by regional-scale wind and turbulent mixing transfers colder air from the park to urban areas in its vicinity. The extent of the park's thermal influence on the town was greater on the downwind side of the park (450 m) than on the upwind side (65 m). The extent was also greater in an area where the terrain slopes down toward the town. Even on calm nights, the extent of the thermal influence extended by the park breeze to an average of 200 m from the park boundary. The park breeze was characterized by its divergent flow in a horizontal plane, which was found to develop well in calm conditions late at night (regional scale wind <1.5 m s and after 02:00 LST). The average magnitude of the cooling effect of the park breeze was estimated at 39 Wm. This green space tempered the hot summer nights on a city block scale. These findings can help urban planners in designing a heat-adapted city. PMID:26828168

  4. The James Webb Space Telescope instrument suite layout: optical system engineering considerations for a large deployable space telescope

    NASA Astrophysics Data System (ADS)

    Bos, Brent J.; Davila, Pamela S.; Jurotich, Matthew; Hobbs, Gurnie; Lightsey, Paul A.; Contreras, James; Whitman, Tony

    2004-10-01

    The James Webb Space Telescope (JWST) is a space-based, infrared observatory designed to study the early stages of galaxy formation in the Universe. The telescope will be launched into orbit about the second Lagrange point and passively cooled to 30-50 K to enable astronomical observations from 0.6 to 28 μm. A group from the NASA Goddard Space Flight Center and the Northrop Grumman Space Technology prime contractor team has developed an optical and mechanical layout for the science instruments within the JWST field of view that satisfies the mission requirements. Four instruments required accommodation within the telescope"s field of view: a Near-Infrared Camera (NIRCam), a Near-Infrared Spectrometer (NIRSpec), a Mid-Infrared Instrument (MIRI) and a Fine Guidance Sensor (FGS) with a tunable filter module. The size and position of each instrument"s field of view allocation were developed through an iterative, concurrent engineering process involving key observatory stakeholders. While some of the system design considerations were those typically encountered during the development of an infrared observatory, others were unique to the deployable and controllable nature of JWST. This paper describes the optical and mechanical issues considered during the field of view layout development, as well as the supporting modeling and analysis activities.

  5. Identifying Space Use at Foraging Arena Scale within the Home Ranges of Large Herbivores.

    PubMed

    Owen-Smith, Norman; Martin, Jodie

    2015-01-01

    An intermediate spatiotemporal scale of food procurement by large herbivores is evident within annual or seasonal home ranges. It takes the form of settlement periods spanning several days or weeks during which foraging activity is confined to spatially discrete foraging arenas, separated by roaming interludes. Extended by areas occupied for other activities, these foraging arenas contribute towards generating the home range structure. We delineated and compared the foraging arenas exploited by two African large herbivores, sable antelope (a ruminant) and plains zebra (a non-ruminant), using GPS-derived movement data. We developed a novel approach to specifically delineate foraging arenas based on local change points in distance relative to adjoining clusters of locations, and compared its output with modifications of two published methods developed for home range estimation and residence time estimation respectively. We compared how these herbivore species responded to seasonal variation in food resources and how they differed in their spatial patterns of resource utilization. Sable antelope herds tended to concentrate their space use locally, while zebra herds moved more opportunistically over a wider set of foraging arenas. The amalgamated extent of the foraging arenas exploited by sable herds amounted to 12-30 km2, compared with 22-100 km2 for the zebra herds. Half-day displacement distances differed between settlement periods and roaming interludes, and zebra herds generally shifted further over 12h than sable herds. Foraging arenas of sable herds tended to be smaller than those of zebra, and were occupied for period twice as long, and hence exploited more intensively in days spent per unit area than the foraging arenas of zebra. For sable both the intensity of utilization of foraging arenas and proportion of days spent in foraging arenas relative to roaming interludes declined as food resources diminished seasonally, while zebra showed no seasonal variation

  6. Identifying Space Use at Foraging Arena Scale within the Home Ranges of Large Herbivores

    PubMed Central

    Owen-Smith, Norman; Martin, Jodie

    2015-01-01

    An intermediate spatiotemporal scale of food procurement by large herbivores is evident within annual or seasonal home ranges. It takes the form of settlement periods spanning several days or weeks during which foraging activity is confined to spatially discrete foraging arenas, separated by roaming interludes. Extended by areas occupied for other activities, these foraging arenas contribute towards generating the home range structure. We delineated and compared the foraging arenas exploited by two African large herbivores, sable antelope (a ruminant) and plains zebra (a non-ruminant), using GPS-derived movement data. We developed a novel approach to specifically delineate foraging arenas based on local change points in distance relative to adjoining clusters of locations, and compared its output with modifications of two published methods developed for home range estimation and residence time estimation respectively. We compared how these herbivore species responded to seasonal variation in food resources and how they differed in their spatial patterns of resource utilization. Sable antelope herds tended to concentrate their space use locally, while zebra herds moved more opportunistically over a wider set of foraging arenas. The amalgamated extent of the foraging arenas exploited by sable herds amounted to 12-30 km2, compared with 22-100 km2 for the zebra herds. Half-day displacement distances differed between settlement periods and roaming interludes, and zebra herds generally shifted further over 12h than sable herds. Foraging arenas of sable herds tended to be smaller than those of zebra, and were occupied for period twice as long, and hence exploited more intensively in days spent per unit area than the foraging arenas of zebra. For sable both the intensity of utilization of foraging arenas and proportion of days spent in foraging arenas relative to roaming interludes declined as food resources diminished seasonally, while zebra showed no seasonal variation

  7. Applications of tuned mass dampers to improve performance of large space mirrors

    NASA Astrophysics Data System (ADS)

    Yingling, Adam J.; Agrawal, Brij N.

    2014-01-01

    In order for future imaging spacecraft to meet higher resolution imaging capability, it will be necessary to build large space telescopes with primary mirror diameters that range from 10 m to 20 m and do so with nanometer surface accuracy. Due to launch vehicle mass and volume constraints, these mirrors have to be deployable and lightweight, such as segmented mirrors using active optics to correct mirror surfaces with closed loop control. As a part of this work, system identification tests revealed that dynamic disturbances inherent in a laboratory environment are significant enough to degrade the optical performance of the telescope. Research was performed at the Naval Postgraduate School to identify the vibration modes most affecting the optical performance and evaluate different techniques to increase damping of those modes. Based on this work, tuned mass dampers (TMDs) were selected because of their simplicity in implementation and effectiveness in targeting specific modes. The selected damping mechanism was an eddy current damper where the damping and frequency of the damper could be easily changed. System identification of segments was performed to derive TMD specifications. Several configurations of the damper were evaluated, including the number and placement of TMDs, damping constant, and targeted structural modes. The final configuration consisted of two dampers located at the edge of each segment and resulted in 80% reduction in vibrations. The WFE for the system without dampers was 1.5 waves, with one TMD the WFE was 0.9 waves, and with two TMDs the WFE was 0.25 waves. This paper provides details of some of the work done in this area and includes theoretical predictions for optimum damping which were experimentally verified on a large aperture segmented system.

  8. Uniaxial and biaxial tensioning effects on thin membrane materials. [large space structures

    NASA Technical Reports Server (NTRS)

    Hinson, W. F.; Goslee, J. W.

    1980-01-01

    Thin laminated membranes are being considered for various surface applications on future large space structural systems. Some of the thin membranes would be stretched across or between structural members with the requirement that the membrane be maintained within specified limits of smoothness which would be dictated by the particular applications such as antenna reflector requirements. The multiaxial tensile force required to maintain the smoothness in the membrane needs to be determined for use in the structure design. Therefore, several types of thicknesses of thin membrane materials have been subjected to varied levels of uniaxial and biaxial tensile loads. During the biaxial tests, deviations of the material surface smoothness were measured by a noncontacting capacitance probe. Basic materials consisted of composites of vacuum deposited aluminum on Mylar and Kapton ranging in thickness from 0.00025 in (0.000635 cm) to 0.002 in (0.00508 cm). Some of the material was reinforced with Kevlar and Nomex scrim. The uniaxial tests determined the material elongation and tensile forces up to ultimate conditions. Biaxial tests indicated that a relatively smooth material surface could be achieved with tensile force of approximately 1 to 15 Newtons per centimeter, depending upon the material thickness and/or reinforcement.

  9. Structural Feasibility Analysis of a Robotically Assembled Very Large Aperture Optical Space Telescope

    NASA Technical Reports Server (NTRS)

    Wilkie, William Keats; Williams, R. Brett; Agnes, Gregory S.; Wilcox, Brian H.

    2007-01-01

    This paper presents a feasibility study of robotically constructing a very large aperture optical space telescope on-orbit. Since the largest engineering challenges are likely to reside in the design and assembly of the 150-m diameter primary reflector, this preliminary study focuses on this component. The same technology developed for construction of the primary would then be readily used for the smaller optical structures (secondary, tertiary, etc.). A reasonable set of ground and on-orbit loading scenarios are compiled from the literature and used to define the structural performance requirements and size the primary reflector. A surface precision analysis shows that active adjustment of the primary structure is required in order to meet stringent optical surface requirements. Two potential actuation strategies are discussed along with potential actuation devices at the current state of the art. The finding of this research effort indicate that successful technology development combined with further analysis will likely enable such a telescope to be built in the future.

  10. Space-charge limited transport in large-area monolayer hexagonal boron nitride.

    PubMed

    Mahvash, Farzaneh; Paradis, Etienne; Drouin, Dominique; Szkopek, Thomas; Siaj, Mohamed

    2015-04-01

    Hexagonal boron nitride (hBN) is a wide-gap material that has attracted significant attention as an ideal dielectric substrate for 2D crystal heterostructures. We report here the first observation of in-plane charge transport in large-area monolayer hBN, grown by chemical vapor deposition. The quadratic scaling of current with voltage at high bias corresponds to a space-charge limited conduction mechanism, with a room-temperature mobility reaching up to 0.01 cm(2)/(V s) at electric fields up to 100 kV/cm in the absence of dielectric breakdown. The observation of in-plane charge transport highlights the semiconducting nature of monolayer hBN, and identifies hBN as a wide-gap 2D crystal capable of supporting charge transport at high field. Future exploration of charge transport in hBN is motivated by the fundamental study of UV optoelectronics and the massive Dirac fermion spectrum of hBN. PMID:25730309

  11. A Very Large Area Network (VLAN) knowledge-base applied to space communication problems

    NASA Astrophysics Data System (ADS)

    Zander, Carol S.

    1988-10-01

    This paper first describes a hierarchical model for very large area networks (VLAN). Space communication problems whose solution could profit by the model are discussed and then an enhanced version of this model incorporating the knowledge needed for the missile detection-destruction problem is presented. A satellite network or VLAN is a network which includes at least one satellite. Due to the complexity, a compromise between fully centralized and fully distributed network management has been adopted. Network nodes are assigned to a physically localized group, called a partition. Partitions consist of groups of cell nodes with one cell node acting as the organizer or master, called the Group Master (GM). Coordinating the group masters is a Partition Master (PM). Knowledge is also distributed hierarchically existing in at least two nodes. Each satellite node has a back-up earth node. Knowledge must be distributed in such a way so as to minimize information loss when a node fails. Thus the model is hierarchical both physically and informationally.

  12. Degradation mechanisms of materials for large space systems in low Earth orbit

    NASA Technical Reports Server (NTRS)

    Gordon, William L.; Hoffman, R. W.

    1987-01-01

    Degradation was explored of various materials used in aerospace vehicles after severe loss of polymeric material coatings (Kapton) was observed on an early shuttle flight in low Earth orbit. Since atomic oxygen is the major component of the atmosphere at 300 km, and the shuttle's orbital velocity produced relative motion corresponding to approx. 5 eV of oxygen energy, it was natural to attribute much of this degradation to oxygen interaction. This assumption was tested using large volume vacuum systems and ion beam sources, in an exploratory effort to produce atomic oxygen of the appropriate energy, and to observe mass loss from various samples as well as optical radiation. Several investigations were initiated and the results of these investigations are presented in four papers. These papers are summarized. They are entitled: (1) The Space Shuttle Glow; (2) Laboratory Degradation of Kapton in a Low Energy Oxygen Ion Beam; (3) The Energy Dependence and Surface Morphology of Kapton Degradation Under Atomic Oxygen Bombardment; and (4) Surface Analysis of STS 8 Samples.

  13. Solution of the flyby problem for large space debris at sun-synchronous orbits

    NASA Astrophysics Data System (ADS)

    Baranov, A. A.; Grishko, D. A.; Medvedevskikh, V. V.; Lapshin, V. V.

    2016-05-01

    the paper considers the flyby problem related to large space debris (LSD) objects at low earth orbits. The data on the overall dimensions of known last and upper stages of launch vehicles makes it possible to single out five compact groups of such objects from the NORAD catalog in the 500-2000 km altitude interval. The orbits of objects of each group have approximately the same inclinations. The features of the mutual distribution of the orbital planes of LSD objects in the group are shown in a portrait of the evolution of deviations of the right ascension of ascending nodes (RAAN). In the case of the first three groups (inclinations of 71°, 74°, and 81°), the straight lines of relative RAAN deviations of object orbits barely intersect each other. The fourth (83°) and fifth (97°-100°) LSD groups include a considerable number of objects whose orbits are described by straight lines (diagonals), which intersect other lines many times. The use of diagonals makes it possible to significantly reduce the temporal and total characteristic velocity expenditures required for object flybys, but it complicates determination of the flyby sequence. Diagonal solutions can be obtained using elements of graph theory. A solution to the flyby problem is presented for the case of group 5, formed of LSD objects at sun-synchronous orbits.

  14. Very large space structures: Non-linear control and robustness to structural uncertainties

    NASA Astrophysics Data System (ADS)

    Gasbarri, Paolo; Monti, Riccardo; Sabatini, Marco

    2014-01-01

    Very Large Space Structures (VLSS) are challenging systems to be controlled, due to their high flexibility. In particular, rapid attitude maneuvers can determine great oscillations on the flexible elements of a spacecraft (solar wings, antennas, booms). On account of this, in the last decades many researchers have developed different strategies to effectively damp the elastic vibrations by means of active vibration devices (such as piezo-electric patches) or by means of robust control algorithms. The approach suggested in this paper is different, since neither additional devices nor complex control laws are introduced. In fact, the complete model of the system (including rigid, elastic and orbital dynamics, coupled with control actions) is controlled by the non-linear attitude controller named state dependent Riccati equation, which will be based on a simplified version of the spacecraft model. The task to reduce the mutual interaction between rigid attitude and flexible dynamics is entirely transferred to a modification of the desired trajectory that must be tracked. This command shaping technique is based on the knowledge of the parameters (inertial and elastics) of the VLSS. Unfortunately these parameters are not always exactly known and, however, they may change over the time. On account of this a Monte Carlo analysis has been also performed, showing the robustness of the proposed control strategy to the structural uncertainties. The numerical simulations prove that this strategy, based on the joint application of two well-known yet simple techniques, produces accurate and robust results.

  15. A Very Large Area Network (VLAN) knowledge-base applied to space communication problems

    NASA Technical Reports Server (NTRS)

    Zander, Carol S.

    1988-01-01

    This paper first describes a hierarchical model for very large area networks (VLAN). Space communication problems whose solution could profit by the model are discussed and then an enhanced version of this model incorporating the knowledge needed for the missile detection-destruction problem is presented. A satellite network or VLAN is a network which includes at least one satellite. Due to the complexity, a compromise between fully centralized and fully distributed network management has been adopted. Network nodes are assigned to a physically localized group, called a partition. Partitions consist of groups of cell nodes with one cell node acting as the organizer or master, called the Group Master (GM). Coordinating the group masters is a Partition Master (PM). Knowledge is also distributed hierarchically existing in at least two nodes. Each satellite node has a back-up earth node. Knowledge must be distributed in such a way so as to minimize information loss when a node fails. Thus the model is hierarchical both physically and informationally.

  16. The dynamics and control of large flexible space structures - 12, supplement 11

    NASA Technical Reports Server (NTRS)

    Bainum, Peter M.; Reddy, A. S. S. R.; Li, Feiyue; Xu, Jianke

    1989-01-01

    The rapid 2-D slewing and vibrational control of the unsymmetrical flexible SCOLE (Spacecraft Control Laboratory Experiment) with multi-bounded controls is considered. Pontryagin's Maximum Principle is applied to the nonlinear equations of the system to derive the necessary conditions for the optimal control. The resulting two point boundary value problem is then solved by using the quasilinearization technique, and the near minimum time is obtained by sequentially shortening the slewing time until the controls are near the bang-bang type. The tradeoff between the minimum time and the minimum flexible amplitude requirements is discussed. The numerical results show that the responses of the nonlinear system are significantly different from those of the linearized system for rapid slewing. The SCOLE station-keeping closed loop dynamics are re-examined by employing a slightly different method for developing the equations of motion in which higher order terms in the expressions for the mast modal shape functions are now included. A preliminary study on the effect of actuator mass on the closed loop dynamics of large space systems is conducted. A numerical example based on a coupled two-mass two-spring system illustrates the effect of changes caused in the mass and stiffness matrices on the closed loop system eigenvalues. In certain cases the need for redesigning control laws previously synthesized, but not accounting for actuator masses, is indicated.

  17. Study of auxiliary propulsion requirements for large space systems. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Smith, W. W.; Machles, G. W.

    1983-01-01

    An insight into auxiliary propulsion systems (APS) requirements for large space systems (LSS) launchable by a single shuttle is presented. In an effort to scope the APS requirements for LSS, a set of generic LSSs were defined. For each generic LSS class a specific structural configuration, representative of that most likely to serve the needs of the 1980's and 1990's was defined. The environmental disturbance forces and torques which would be acting on each specific structural configuration in LEO and GEO orbits were then determined. Auxiliary propulsion requirements were determined as a function of: generic class specific configuration, size and openness of structure, orbit, angle of orientation, correction frequency, duty cycle, number and location of thrusters and direction of thrusters and APS/LSS interactions. The results of this analysis were used to define the APS characteristics of: (1) number and distribution of thrusters, (2) thruster modulation, (3) thrust level, (4) mission energy requirements, (5) total APS mass component breakdown, and (6) state of the art adequacy/deficiency.

  18. Ultrahigh-accuracy body-pointing system for the Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Rybak, S. C.; Mayo, R. A.; Lieberman, S. I.; Hartter, L. L.

    1976-01-01

    The Large Space Telescope (LST) is a 3-m diffraction-limited telescope. Pointing stability requirements necessary to assure diffraction-limited images are plus or minus 0.005 arc-sec, over possible experiment observation times of several hours. In order to determine whether these stringent pointing requirements could be met, a complex simulation model was defined which consisted of detailed dynamic representations of control moment gyros (CMGs) and reaction wheels (RWs), including their noise characteristics, dynamic sensor representations with sensor noise, shock mounts for the CMG actuators, a detailed representation of an image motion compensation (IMC) system, and a detailed flexible body structural model with all significant vehicle and solar panel bending modes. On the basis of both stability and performance studies utilizing this model, it was determined that a body-pointing system will meet LST requirements in the presence of CMG vibrational disturbances and sensor noise. The recommended system consists of three orthogonally mounted RWs for primary short-term control, and a cluster of CMG actuators for continuous RW desaturation and vehicle maneuvering.

  19. Optimal placement of semi-active joints in large-space truss structures

    NASA Astrophysics Data System (ADS)

    Wirnitzer, Jan; Kistner, A.; Gaul, Lothar

    2002-06-01

    The low structural damping of large space structures and the stringent positioning requirements in missions demand effective vibration suppression. The semi-active approach at hand is based on friction damping due to interfacial slip in semi-active joints which can be controlled by varying the normal pressure in the contact area using a piezo-disc actuator. This paper focuses on the optimal placement of semi-active joints for vibration suppression. The proposed method uses optimality criteria for actuator and sensor locations based on eigenvalues of the controllability and observability gramians. It is stated as a nonlinear multicriteria optimization problem with discrete variables which is solved by a stochastic search algorithm. As final step in the design procedure, parameters of the local feedback controllers assigned to each adaptive joint are optimized with respect to transient response of the structure. The present method is applied to a 10-bay truss structure. Simulation runs of the controlled structure are used to verify the optimization results.

  20. Micro-precision control/structure interaction technology for large optical space systems

    NASA Technical Reports Server (NTRS)

    Sirlin, Samuel W.; Laskin, Robert A.

    1993-01-01

    The CSI program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation. The wavelength is about 0.5 micron for visible light and 0.1 micron for ultra-violet light. This lambda/50 requirement is common to a broad class of optical systems including filled aperture telescopes (with monolithic or segmented primary mirrors), sparse aperture telescopes, and optical interferometers. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on a lightweight, flexible structure. In order to better understand the requirements for micro-precision CSI technology, a representative future optical system was identified and developed as an analytical testbed for CSI concepts and approaches. An optical interferometer was selected as a stressing example of the relevant mission class. The system that emerged was termed the Focus Mission Interferometer (FMI). This paper will describe the multi-layer control architecture used to address the FMI's nanometer level stabilization requirements. In addition the paper will discuss on-going and planned experimental work aimed at demonstrating that multi-layer CSI can work in practice in the relevant performance regime.