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Sample records for large spacing loop-loop

  1. 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.

  2. 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).

  3. 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.

  4. Is a closing "GA pair" a rule for stable loop-loop RNA complexes?

    PubMed

    Ducongé, F; Di Primo, C; Toulme, J J

    2000-07-14

    RNA hairpin aptamers specific for the trans-activation-responsive (TAR) RNA element of human immunodeficiency virus type 1 were identified by in vitro selection (Ducongé, F., and Toulmé, J. J. (1999) RNA 5, 1605-1614). The high affinity sequences selected at physiological magnesium concentration (3 mm) were shown to form a loop-loop complex with the targeted TAR RNA. The stability of this complex depends on the aptamer loop closing "GA pair" as characterized by preliminary electrophoretic mobility shift assays. Thermal denaturation monitored by UV-absorption spectroscopy and binding kinetics determined by surface plasmon resonance show that the GA pair is crucial for the formation of the TAR-RNA aptamer complex. Both thermal denaturation and surface plasmon resonance experiments show that any other "pairs" leads to complexes whose stability decreases in the order AG > GG > GU > AA > GC > UA > CA, CU. The binding kinetics indicate that stability is controlled by the off-rate rather than by the on-rate. Comparison with the complex formed with the TAR* hairpin, a rationally designed TAR RNA ligand (Chang, K. Y., and Tinoco, I. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 8705-8709), demonstrates that the GA pair is a key determinant which accounts for the 50-fold increased stability of the TAR-aptamer complex (K(d) = 2.0 nm) over the TAR-TAR* one (K(d) = 92. 5 nm) at physiological concentration of magnesium. Replacement of the wild-type GC pair next to the loop of RNA I' by a GA pair stabilizes the RNA I'-RNA II' loop-loop complex derived from the one involved in the control of the ColE1 plasmid replication. Thus, the GA pair might be the preferred one for stable loop-loop interactions.

  5. Infrastructure for large space telescopes

    NASA Astrophysics Data System (ADS)

    MacEwen, Howard A.; Lillie, Charles F.

    2016-10-01

    It is generally recognized (e.g., in the National Aeronautics and Space Administration response to recent congressional appropriations) that future space observatories must be serviceable, even if they are orbiting in deep space (e.g., around the Sun-Earth libration point, SEL2). On the basis of this legislation, we believe that budgetary considerations throughout the foreseeable future will require that large, long-lived astrophysics missions must be designed as evolvable semipermanent observatories that will be serviced using an operational, in-space infrastructure. We believe that the development of this infrastructure will include the design and development of a small to mid-sized servicing vehicle (MiniServ) as a key element of an affordable infrastructure for in-space assembly and servicing of future space vehicles. This can be accomplished by the adaptation of technology developed over the past half-century into a vehicle approximately the size of the ascent stage of the Apollo Lunar Module to provide some of the servicing capabilities that will be needed by very large telescopes located in deep space in the near future (2020s and 2030s). We specifically address the need for a detailed study of these servicing requirements and the current proposals for using presently available technologies to provide the appropriate infrastructure.

  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. 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

  8. 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.

  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. Gyrodampers for large space structures

    NASA Technical Reports Server (NTRS)

    Aubrun, J. N.; Margulies, G.

    1979-01-01

    The problem of controlling the vibrations of a large space structures by the use of actively augmented damping devices distributed throughout the structure is addressed. The gyrodamper which consists of a set of single gimbal control moment gyros which are actively controlled to extract the structural vibratory energy through the local rotational deformations of the structure, is described and analyzed. Various linear and nonlinear dynamic simulations of gyrodamped beams are shown, including results on self-induced vibrations due to sensor noise and rotor imbalance. The complete nonlinear dynamic equations are included. The problem of designing and sizing a system of gyrodampers for a given structure, or extrapolating results for one gyrodamped structure to another is solved in terms of scaling laws. Novel scaling laws for gyro systems are derived, based upon fundamental physical principles, and various examples are given.

  11. Paleomagnetism of the Neoproterozoic Blekinge-Dalarna Dolerites in Western Sweden and Implications of the Sveconorwegian Loop(s)

    NASA Astrophysics Data System (ADS)

    Gong, Z.; Evans, D. A.; Elming, S. A.

    2016-12-01

    Laurentia and Baltica are regarded to be juxtaposed at the core of the supercontinent Rodinia during Early Neoproterozoic. This contention is supported by the similar apparent polar wander paths (APWPs) of Laurentia and Baltica, known as the Grenville and the Sveconorwegian loops, respectively. Despite the debates of the age and shape of the Grenville loop, the Sveconorwegian loop has uncertainties as well. Paleomagnetic studies from Baltica show two distinct remanence directions at ca. 950 Ma: one is steep and upwards (A-type) and another is shallow and bipolar (B-type). The fidelity of B-type remanence is supported by the new key-pole from the 935 ± 5 Ma Blekinge-Dalarna dolerites (BDD) in western Sweden. But A-type remanence, less common, is also observed in the BDD dykes. Some studies attribute A-type remanence to remagnetization without clear evidence. If A-type remanence is primary, this would suggest a large APWP excursion of Baltica within a very short duration, analogous to the mid-Ediacaran situation of Laurentia that has been explained by different hypotheses such as true polar wander, unusual geomagnetic configuration or rapid plate motions. Therefore, we conducted a more detailed paleomagnetic study of the BDD dykes that cover an area of 10,000 km2. We propose a combined geochemical and magnetic fabric study to compare BDD dykes' signatures with published results to aid field identification. Thermal demagnetization is conducted and the fidelity of the remanence is examined by rigorous baked contact tests in different host rocks. Dykes with primary remanence will be radiometrically dated to constrain the age of the remanence. This study should have wide implications, in particular the configuration of Sveconorwegian loop(s) in Early Neoproterozoic time, the paleogeographic connection between Laurentia and Baltica in Rodinia, as well as the geodynamics in Earth's deep interior.

  12. 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.

  13. Role of loop-loop interactions in coordinating motions and enzymatic function in triosephosphate isomerase.

    PubMed

    Wang, Yan; Berlow, Rebecca B; Loria, J Patrick

    2009-06-02

    The enzyme triosephosphate isomerase (TIM) has been used as a model system for understanding the relationship between protein sequence, structure, and biological function. The sequence of the active site loop (loop 6) in TIM is directly correlated with a conserved motif in loop 7. Replacement of loop 7 of chicken TIM with the corresponding loop 7 sequence from an archaeal homologue caused a 10(2)-fold loss in enzymatic activity, a decrease in substrate binding affinity, and a decrease in thermal stability. Isotope exchange studies performed by one-dimensional (1)H NMR showed that the substrate-derived proton in the enzyme is more susceptible to solvent exchange for DHAP formation in the loop 7 mutant than for WT TIM. TROSY-Hahn Echo and TROSY-selected R(1rho) experiments indicate that upon mutation of loop 7, the chemical exchange rate for active site loop motion is nearly doubled and that the coordinated motion of loop 6 is reduced relative to that of the WT. Temperature dependent NMR experiments show differing activation energies for the N- and C-terminal hinges in this mutant enzyme. Together, these data suggest that interactions between loop 6 and loop 7 are necessary to provide the proper chemical context for the enzymatic reaction to occur and that the interactions play a significant role in modulating the chemical dynamics near the active site.

  14. 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.

  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. On the triggering of M-class solar flare due to loop-loop interaction in AR NOAA 10875

    NASA Astrophysics Data System (ADS)

    Kumar, Pankaj; Srivastava, Abhishek K.; Somov, B. V.; Manoharan, P. K.; Erdélyi, R.; Uddin, Wahab

    We present multiwavelength analysis of an M7.9 /1N solar flare which occurred on 27 April 2006 in AR NOAA 10875. The flare was triggered due to the interaction of two loop systems. GOES soft X-ray and TRACE 195 Å image sequences show the observational evidences of 3-D X-type loop-loop interaction with converging motion at the interaction site. We found the following characteristics during the loop-loop interaction: (i) a short duration/impulsive flare obeying the Neupart effect, (ii) double peak structure in radio flux profiles (in 4.9 and 8.8 GHz), (iii) quasi-periodic oscillations in the radio flux profiles for the duration of ˜3 min, (iv) absence of CME and type III radio burst. The above characteristics observed during the flare are in agreement with the theory and simulation of current loop coalescence by Sakai et al. (1986). These are unique multiwavelength observations, which provide the evidences of loop-loop interaction and associated triggering of solar flare without CME.

  17. 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.

  18. 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.

  19. Large Space Structures Fielding Plan

    DTIC Science & Technology

    1991-01-01

    el to the of1wci Manegement and Budget. Papenvoik Reduion PcIW (0704-01.), Weeg. DC . 1. AGENCY USE ONLY (Lemve Blnk) 2. REPORT DATE 3.REPORT TYPE AND...Systems Fabrication 17 Quality Assurance Verification 17 Acceptance Testing/ Safety Analysis 18 Launch Site Operations 19 Orbital Construction 19...generic to the space industry, and to a great extent reflect the safety , quality assurance, and verification plans that NASA has used on previous

  20. 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.

  1. Large space reflector technology on the Space Station

    NASA Technical Reports Server (NTRS)

    Mankins, J. C.; Dickinson, R. M.; Freeland, R. E.; Marzwell, N. I.

    1986-01-01

    This paper discusses the role of the Space Station in the evolutionary development of large space reflector technology and the accommodation of mission systems which will apply large space reflectors during the late 1990s and the early part of the next century. Reflectors which range from 10 to 100 meters in size and which span the electromagnetic spectrum for applications that include earth communications, earth observations, astrophysics and solar physics, and deep space communications are discussed. The role of the Space Station in large space reflector technology development and system performance demonstration is found to be critical; that role involves the accommodation of a wide variety of technology demonstrations and operational activities on the Station, including reflector deployment and/or assembly, mechanical performance verification and configuration refinement, systematic diagnostics of reflector surfaces, structural dynamics and controls research, overall system performance characterization and modification (including both radio frequency field pattern measurements and required end-to-end system demonstrations), and reflector-to-spacecraft integration and staging. A unique facility for Space Station-based, large space reflector research and development is proposed. A preliminary concept for such a Space Station-based Large Space Reflector Facility (LSRF) is described.

  2. 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

  3. Space fabrication - The key to future large space systems

    NASA Technical Reports Server (NTRS)

    Savage, M.; Hagler, T.

    1980-01-01

    Construction techniques for large space structures are discussed. It is pointed out that in contrast to assembly in orbit and the deployment technique space fabrication offers favorable densities (transporting structural materials on reels) and can be adapted to automated construction. A space fabrication machine containing reels of flat sheet material and sets of rollers or dies is described, as is a machine for fabricating composite material (which must be heated for forming and then cooled to achieve structural strength). The use of fabrication machines to build such structures as space platforms, microwave radiometers, and satellite power systems is discussed. The versatility of the machine when operated in conjunction with the Space Shuttle and a set of jigs is illustrated by showing how large square solar panels and large hexagonal structures could be constructed. The need for a flight demonstration of the fabrication machine is stressed.

  4. 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.

  5. 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.

  6. Vibration suppression in a large space structure

    NASA Technical Reports Server (NTRS)

    Narendra, Kumpati S.

    1988-01-01

    The Yale University Center for Systems Science and the NASA Johnson Space Center collaborated in a study of vibration suppression in a large space structure during the period January 1985 to August 1987. The research proposal submitted by the Center to NASA concerned disturbance isolation in flexible space structures. The general objective of the proposal was to create within the Center a critical mass of expertise on problems related to the dynamics and control of large flexible space structures. A specific objective was to formulate both passive and active control strategies for the disturbance isolation problem. Both objectives were achieved during the period of the contract. While an extensive literature exists on the control of flexible space structures, it is generally acknowledged that many important questions remain open at even a fundamental level. Hence, instead of studying grossly simplified models of complex structural systems, it was decided as a first step to confine attention to detailed and thorough analyses of simple structures.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Space Station Freedom: Dynamic instrumentation for a large space structure

    NASA Technical Reports Server (NTRS)

    Raney, John P.; Cooper, Paul A.; Johnson, James W.

    1990-01-01

    A proposed approach called Modal Identification Experiment (MIE) for obtaining on-orbit dynamic response measurements on Space Station Freedom, the first of a family of large, flexible space structures is discussed. The Phase 2 conceptual design study which provides a conceptual design of a proposed measurement system and an experimental protocol for inobstrusively collecting dynamic response data critical to characterizing important vibration modes of Space Station Freedom were recently concluded. The case for conducting such a measurement program is presented and the specific MIE objectives that were identified, are listed. The sequence of discrete Space Station Freedom assembly configurations is described, and the Phase 2 conceptual design of the experiment and instrumentation system are defined. In addition, a plan to utilize a space station hydrid scale model in laboratory simulations as part of the design process are discussed.

  14. Dynamics and control of large space structures

    NASA Technical Reports Server (NTRS)

    Nurre, G. S.; Ryan, R. S.; Scofield, H. N.; Sims, J. L.

    1984-01-01

    An attempt is made to gather data useful to investigators in the fields of large space structure dynamics and control modeling, design and testing. Attention is given to structural dynamics and its relationship to such allied engineering fields as flutter analysis, as well as to problems in the prediction of atmospheric density at orbital altitude. The first challenge posed by large space structure control is the design of control systems with natural frequencies above several major structural frequencies. The establishment of a sufficiently accurate structural model, plant excitation, and shape maintenance, are noted to be additional problems.

  15. Identification of large space structures - Overview

    NASA Technical Reports Server (NTRS)

    Denman, Eugene; Juang, Jer-Nan; Junkins, John; Kamat, Manohar; Hasselman, T. K.

    1988-01-01

    The system identification process presently discussed for the case of large space structures uses the observed input to a system and its observed response, or output, to derive an analytical model of the system which can then be used to predict its response to future inputs. Due to their size and complexity, as well as the intrinsic difficulty of identifying the environment in which they function, large space structures will require vast amounts of information, encompassing both experimental and analytical data for identification. A status evaluation is made of the structural system identification literature to date.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Environmental interaction implications for large space systems

    NASA Technical Reports Server (NTRS)

    Miller, E.; Fischbein, W.; Stauber, M. C.; Suh, P. K.

    1979-01-01

    Large Space Systems (LSS) comprise a new class of spacecraft, the design and performance of which may be seriously affected by a variety of environmental interactions. The special concerns associated with spacecraft charging and plasma interactions from the LSS designer's viewpoint are addressed. Survivability of these systems under combined solar U.V., particle radiation and repeated electrical discharges is of primary importance. Additional questions regard the character of electrical discharges over very large areas, the effects of high current/voltage systems and magnitude of induced structural disturbances. A concept is described for a large scale experiment platform.

  4. Similarity searching in large combinatorial chemistry spaces

    NASA Astrophysics Data System (ADS)

    Rarey, Matthias; Stahl, Martin

    2001-06-01

    We present a novel algorithm, called Ftrees-FS, for similarity searching in large chemistry spaces based on dynamic programming. Given a query compound, the algorithm generates sets of compounds from a given chemistry space that are similar to the query. The similarity search is based on the feature tree similarity measure representing molecules by tree structures. This descriptor allows handling combinatorial chemistry spaces as a whole instead of looking at subsets of enumerated compounds. Within few minutes of computing time, the algorithm is able to find the most similar compound in very large spaces as well as sets of compounds at an arbitrary similarity level. In addition, the diversity among the generated compounds can be controlled. A set of 17 000 fragments of known drugs, generated by the RECAP procedure from the World Drug Index, was used as the search chemistry space. These fragments can be combined to more than 1018 compounds of reasonable size. For validation, known antagonists/inhibitors of several targets including dopamine D4, histamine H1, and COX2 are used as queries. Comparison of the compounds created by Ftrees-FS to other known actives demonstrates the ability of the method to jump between structurally unrelated molecule classes.

  5. Dynamics of rotationally periodic large space structure

    NASA Technical Reports Server (NTRS)

    Mcdaniel, T. J.; Chang, K. J.

    1980-01-01

    The analysis of large area rotationally periodic space structures presented in the paper combines the finite element method, transfer matrix procedures, approximation methods, and periodic structure analysis to obtain computational efficiency. The computations used in the analysis indicate that additive damping mechanisms can be evaluated from the frequency response of the structure. The transient response can also be obtained from the frequency response to complete the dynamic analysis.

  6. Very large aperture optics for space applications

    NASA Astrophysics Data System (ADS)

    Horwath, T. G.; Smith, J. P.; Johnson, M. T.

    1994-09-01

    A new type of space optics technology is presented which promises the realization of very large apertures (tens of meters), while packagable into lightweight, small volume containers compatible with conventional launch vehicles. This technology makes use of thin foils of circular shape which are uniformly mass loaded around the perimeter. Once unfurled and set into rapid rotation about the transversal axis, the foil is stretched into a perfectly flat plane by the centrifugal forces acting on the peripheral masses. The simplest applications of this novel technology are optically flat reflectors, using metallized foils of Mylar, Kevlar, or Kapton. Other more complex optical components can be realized by use of binary optics techniques, such as depositing holograms by selective local microscale removal of the reflective surface. Electrostatic techniques, in conjunction with an auxiliary foil, under local, distributed real-time control of the optical parameters, allow implementation of functions like beam steering and focal length adjustments. Gas pressurization allows stronger curvatures and thus smaller focal ratios for non-imaging applications. Limits on aperture are imposed primarily by manufacturing capabilities. Applications of such large optics in space are numerous. They range from military, such as space based lasers, to the civilian ones of power beaming, solar energy collection, and astronomy. This paper examines this simple and innovative concept in detail, discusses deployment and attitude control issues and presents approaches for realization.

  7. 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.

  8. Navigating large hierarchical space using invisible links

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Hsu, Meichun; Dayal, Umeshwar; Krug, Adrian

    2000-02-01

    To date, many web visualization applications have shown the usefulness of a hyperbolic tree. However, we have discovered that strict hierarchical tree structures are too limited. For many practical applications, we need to generalize a hyperbolic tree to a hyperbolic space. This approach results in massive cross-links in a highly connected graph that clutter the display. To resolve this problem, an invisible link technique is introduced. In this paper. we describe the navigation in a large hyperbolic space using invisible links in some detail. We have applied this invisible link method to three data mining visualization applications: e-business web navigation for URL visits, customer call center for question-answer service, and web site index creation.

  9. 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.

  10. Concepts for large interferometers in space

    NASA Technical Reports Server (NTRS)

    Morgan, S. H.; Nein, M. E.; Davis, B. G.; Hamilton, E. C.; Roberts, D. H.; Traub, W. A.

    1982-01-01

    Very high angular resolution can be achieved in optical and radio astronomy through interferometers in space. Evolutionary approaches and required technological advances are presented. In the optical region a phase-coherent array, (COSMIC) starting as a four-element linear array is discussed. Combining several modules results in greatly improved resolution with a goal of combining images to obtain a single field of view with 0.004 arcsecond resolution. The angular resolution, detail and temporal coverage of radio maps obtained by ground-based Very Long Interferometry (VLBI) can be greatly improved by placing one of the stations in earth orbit. An evolutionary program leading to a large aperture VLBI observatory in space is discussed.

  11. 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.

  12. 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.

  13. 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.

  14. Metrication study for large space telescope

    NASA Technical Reports Server (NTRS)

    Creswick, F. A.; Weller, A. E.

    1973-01-01

    Various approaches which could be taken in developing a metric-system design for the Large Space Telescope, considering potential penalties on development cost and time, commonality with other satellite programs, and contribution to national goals for conversion to the metric system of units were investigated. Information on the problems, potential approaches, and impacts of metrication was collected from published reports on previous aerospace-industry metrication-impact studies and through numerous telephone interviews. The recommended approach to LST metrication formulated in this study cells for new components and subsystems to be designed in metric-module dimensions, but U.S. customary practice is allowed where U.S. metric standards and metric components are not available or would be unsuitable. Electrical/electronic-system design, which is presently largely metric, is considered exempt from futher metrication. An important guideline is that metric design and fabrication should in no way compromise the effectiveness of the LST equipment.

  15. 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

  16. Structural design methodology for large space structures

    NASA Astrophysics Data System (ADS)

    Dornsife, Ralph J.

    The Department of Defense requires research and development in designing, fabricating, deploying, and maintaining large space structures (LSS) in support of Army and Strategic Defense Initiative military objectives. Because of their large size, extreme flexibility, and the unique loading conditions in the space environment, LSS will present engineers with problems unlike those encountered in designing conventional civil engineering or aerospace structures. LSS will require sophisticated passive damping and active control systems in order to meet stringent mission requirements. These structures must also be optimally designed to minimize high launch costs. This report outlines a methodology for the structural design of LSS. It includes a definition of mission requirements, structural modeling and analysis, passive damping and active control system design, ground-based testing, payload integration, on-orbit system verification, and on-orbit assessment of structural damage. In support of this methodology, analyses of candidate LSS truss configurations are presented, and an algorithm correlating ground-based test behavior to expected microgravity behavior is developed.

  17. Structural design methodology for large space structures

    NASA Astrophysics Data System (ADS)

    Dornsife, Ralph J.

    1992-02-01

    The Department of Defense requires research and development in designing, fabricating, deploying, and maintaining large space structures (LSS) in support of Army and Strategic Defense Initiative military objectives. Because of their large size, extreme flexibility, and the unique loading conditions in the space environment, LSS will present engineers with problems unlike those encountered in designing conventional civil engineering or aerospace structures. LSS will require sophisticated passive damping and active control systems in order to meet stringent mission requirements. These structures must also be optimally designed to minimize high launch costs. This report outlines a methodology for the structural design of LSS. It includes a definition of mission requirements, structural modeling and analysis, passive damping and active control system design, ground-based testing, payload integration, on-orbit system verification, and on-orbit assessment of structural damage. In support of this methodology, analyses of candidate LSS truss configurations are presented, and an algorithm correlating ground-based test behavior to expected microgravity behavior is developed.

  18. James Webb Space Telescope: large deployable cryogenic telescope in space

    NASA Astrophysics Data System (ADS)

    Lightsey, Paul A.; Atkinson, Charles; Clampin, Mark; Feinberg, Lee D.

    2012-01-01

    The James Webb Space Telescope (JWST) is an infrared space telescope designed to explore four major science themes: first light and reionization, the assembly of galaxies, the birth of stars and protoplanetary systems, and planetary systems and origins of life. JWST is a segmented architecture telescope with an aperture of 6.6 m. It will operate at cryogenic temperature (40 K), achieved via passive cooling, in an orbit about the Earth-Sun second Lagrange point (L2). Passive cooling is facilitated by means of a large sunshield that provides thermal isolation and protection from direct illumination from the Sun. The large size of the telescope and spacecraft systems require that they are stowed for launch in a configuration that fits the Ariane 5 fairing, and then deployed after launch. Routine wavefront sensing and control measurements are used to achieve phasing of the segmented primary mirror and initial alignment of the telescope. A suite of instruments will provide the capability to observe over a spectral range from 0.6- to 27-μm wavelengths with imaging and spectroscopic configurations. An overview is presented of the architecture and selected optical design features of JWST are described.

  19. 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.

  20. Aspects of control in large space structures

    NASA Astrophysics Data System (ADS)

    Santini, P.

    Noting that future large space structures (LSS) such as the SPS, communications satellites, and antennas will require a beam amplitude of less than 0.1, vibration amplitudes of less than 0.005, and surface distortion less than 1 mm, a model for the control-structure interaction is formulated qualititively. Considering it an impossibility to effectively control all the parameters of structural frequencies, eigenmodes, and local characteristics, use of modal synthesis is suggested as an alternative to attempting active control of every factor. A feedback control of the first N modes is applied to a discretized system, obtained by truncation f the eigenmodes of the structural operator, and incorporating a priori conditions to avoid uncontrolled modes. Repeated implementation of hierarchicontrol techniques are proposed as an effective means to reduce propellant mass consumption.

  1. Structural attachments for large space structures

    NASA Technical Reports Server (NTRS)

    Pruett, E. C.; Loughead, T. E.; Robertson, K. B., III

    1980-01-01

    The feasibility of fabricating beams in space and using them as components of a large, crew assembled structure, was investigated. Two projects were undertaken: (1) design and development of a ground version of an automated beam builder capable of producing triangular cross section aluminum beams; and (2) design and fabrication of lap joints to connect the beams orthogonally and centroidal end caps to connect beams end to end at any desired angle. The first project produced a beam building machine which fabricates aluminum beams suitable for neutral buoyancy evaluation. The second project produced concepts for the lap joint and end cap. However, neither of these joint concepts was suitable for use by a pressure suited crew member in a zero gravity environment. It is concluded that before the beams can be evaluated the joint designs need to be completed and sufficient joints produced to allow assembly of a complex structure.

  2. 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.

  3. 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.

  4. Primary mirror assemblies for large space telescopes

    NASA Astrophysics Data System (ADS)

    Malamed, Evgeny R.; Sokolsky, M. N.

    1995-09-01

    In this report are considered the basic problems which relate to developemnt, manufacture, experimental trying out, and usage of primary mirrors (PM) of the large space telescopes intended to perform distant sounding of the Earth. Attention is concentrated on development of weight-reduced passive mirrors which ensure more reliable operation of the telescope as a whole. In the report we expressed the opinion that it is quite possible to manufacture a passive weight-reduced PM if its diameter is equal approximately to 3 m. Materials which may be used for the manufacturing of PM are beryllium and silicon carbide, physical and mechanical parameters of which are the most preferable ones. But it should be taken into consideration that this is the glass ceramic of CO115M brand which has been mastered by the industry of Russia in the greatest extent. It was confirmed that parameters of this material remain unchanged during a long period of time. Constructions of the PM, made of glass ceramic, as well as constructions of holders intended to fix the mirror, are presented in this report. A holder is used first of all to prevent lowering of a PM surface quality after a mirror has been removed from a machine and fixed in a primary mirror assembly (PMA). At present two-layer construction of a PM is preferable. This construction consists of thick base including weight reduction structure, which is in a radius which is optimum from the standpoint of deformation of a mirror operating surface. In the process of manufacture a mirror is deprived of its weight with the use of special pneumatic off-loading elements. PMA is erected in vertical plane by means of using an interferometric inspection system. In the end of this report we expressed the views on an approach to engineering of a PM by taking into account potentialities both of space ships and of carrier rockets.

  5. Auxiliary propulsion requirements for large space systems

    NASA Technical Reports Server (NTRS)

    Maloy, J. E.; 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. Previously announced in STAR as N83-26922

  6. Auxiliary propulsion requirements for large space systems

    NASA Technical Reports Server (NTRS)

    Maloy, J. E.; 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.

  7. 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.

  8. 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.

  9. 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.

  10. Evolving Coevolutionary Classifiers Under Large Attribute Spaces

    NASA Astrophysics Data System (ADS)

    Doucette, John; Lichodzijewski, Peter; Heywood, Malcolm

    Model-building under the supervised learning domain potentially face a dual learning problem of identifying both the parameters of the model and the subset of (domain) attributes necessary to support the model, thus using an embedded as opposed to wrapper or filter based design. Genetic Programming (GP) has always addressed this dual problem, however, further implicit assumptions are made which potentially increase the complexity of the resulting solutions. In this work we are specifically interested in the case of classification under very large attribute spaces. As such it might be expected that multiple independent/ overlapping attribute subspaces support the mapping to class labels; whereas GP approaches to classification generally assume a single binary classifier per class, forcing the model to provide a solution in terms of a single attribute subspace and single mapping to class labels. Supporting the more general goal is considered as a requirement for identifying a 'team' of classifiers with non-overlapping classifier behaviors, in which each classifier responds to different subsets of exemplars. Moreover, the subsets of attributes associated with each team member might utilize a unique 'subspace' of attributes. This work investigates the utility of coevolutionary model building for the case of classification problems with attribute vectors consisting of 650 to 100,000 dimensions. The resulting team based coevolutionary evolutionary method-Symbiotic Bid-based (SBB) GP-is compared to alternative embedded classifier approaches of C4.5 and Maximum Entropy Classification (MaxEnt). SSB solutions demonstrate up to an order of magnitude lower attribute count relative to C4.5 and up to two orders of magnitude lower attribute count than MaxEnt while retaining comparable or better classification performance. Moreover, relative to the attribute count of individual models participating within a team, no more than six attributes are ever utilized; adding a further

  11. 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.

  12. 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.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Palaszewski, Bryan

    1993-06-01

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Large Space Structure Charging during Eclipse Passage.

    DTIC Science & Technology

    1980-01-15

    ADDRESS(It different fron Controllng Olfc1 ) IS. SECURITY ::LASS (of In$. report) Unclassified IS.. DE’.LASSIFICATION ’DOWNGRADING SCHEDULE 16 ...as a Function of Vmax, the Eclipse Potential 15 10. Ohmic Power Loss in Solar Power Satellite as a Function of Resistivity 16 Tables 1. Space Plasma...total drop between the ends of the structure 6V. The high-resistance curve is nearly linear, owing to the fact 12 - pHo 4 X10- 6 A/M 2 DA1.0 16 800

  3. 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…

  4. 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.

  5. 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…

  6. Robust control for large space antennas

    NASA Technical Reports Server (NTRS)

    Barrett, M. F.

    1987-01-01

    A brief description of program objectives and the space based radar application is given. General characteristics of the 100 m diameter reflector spacecraft are described along with the intended mission and associated requirements, and dynamic characteristics relevant to that mission. Preliminary control analyses are carried out for the critical rapid slew and settle maneuver to establish feedback control requirements and fundamental limitations in meeting those requirements with control hardware for a baseline reaction control system (RCS) jet placement assumed for the open loop bang-bang slew limitations. Control moment gyros (CMGs), angular position sensors, and linear translation sensors are placed for feedback control. Control laws are designed for the improved sensor and actuator placement and evaluated for performance and robustness to unstructured model uncertainty. The robustness of the control design is assessed with respect to modal parameter uncertainty. Results of the control designs analyses are summarized, conclusions are drawn, and recommendations made for future studies.

  7. Adaptive Techniques for Large Space Apertures.

    DTIC Science & Technology

    1980-03-01

    GP Anitern, 200l de or,~,’rn, receiner/ proceso 1"’ - requires enternal !titude deter- minationr such as a star tracker Increased mechanizatio’ Sensor...control systems into one unit; namely, a fine pointing control using the gimbal rates as the control variables while maintaining constant rotor speeds...CMG mode), and a coarse control for large maneuvers using the rotor speeds as the control variables and locking the gimbals (RW mode). The simultaneous

  8. Application of NASTRAN to large space structures

    NASA Technical Reports Server (NTRS)

    Balderes, T.; Zalesak, J.; Dyreyes, V.; Lee, E.

    1976-01-01

    The application of NASTRAN to design studies of two very large-area lightweight structures is described. The first is the Satellite Solar Power Station, while the second is a deployable three hundred meter diameter antenna. A brief discussion of the operation of the SSPS is given, followed by a description of the structure. The use of the NASTRAN program for static, vibration and thermal analysis is illustrated and some results are given. Next, the deployable antenna is discussed and the use of NASTRAN for static analysis, buckling analysis and vibration analysis is detailed.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Spacecraft charging and plasma interaction implications for large space systems

    NASA Technical Reports Server (NTRS)

    Miller, E.; Stauber, M.; Rossi, M.; Fischbein, W.

    1978-01-01

    Specific discharge mechanisms, plasma interactions, and scale effects associated with very large spacecraft are studied. The large area, low density character, and extensive use of non-conducting materials is thought to have a major impact on the performance and survivability of many large space systems.

  18. 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.

  19. 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.

  20. Creating and testing large space structures of high precision surface

    NASA Astrophysics Data System (ADS)

    Medzmariashvili, Elgudja; Iacobashvili, Alexander; Beducadze, Guram

    The authors describe work on the development of large structures for use in space. This work involves development of structural classes (types), theoretical studis, systems manufacturing and full scale structure testing. Collecting solar energy in space and sending it down to Earth is of great interest to humanity because of the large need for energy on Earth. Building any large solar power station requires industry and construction engineering in space. The problem, as a whole, as well as specific parts thereof virtually always requires certain engineering support, i.e. erection of supporting, reflecting and other large-sized structures in orbit. The Institute of Transformed Structures carries out research, design manufacturing, ground testing and supply of launchable prototypes. The work is performed in an unified manner and contains several trends (categories) which define structures that can be assembled in space.

  1. 7. INTERIOR VIEW OF TYPICAL LARGE OFFICE SPACE, DECOMMISSIONED AFTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. INTERIOR VIEW OF TYPICAL LARGE OFFICE SPACE, DECOMMISSIONED AFTER DAMAGE DURING LAUNCH PAD A EXPLOSION; VIEW TO WEST. - Cape Canaveral Air Station, Launch Complex 17, Facility 36006, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  2. Industry workshop on large space structures: Executive summary

    NASA Technical Reports Server (NTRS)

    Katz, E.

    1976-01-01

    A NASA-sponsored Industry Workshop on Large Space Structures was convened at Langley Research Center on 24-26 February 1976. A number of structures specialists from seven major aerospace companies participated. Predictions about the future structures to be fabricated/assembled/erected in space are presented along with a composite appraisal of what the Aerospace Industry views as the critical structural technology developments needed to support NASA space missions in the 1985-2000 time frame.

  3. 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.

  4. 19. Interior view of large unoccupied office space looking towards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Interior view of large unoccupied office space looking towards opened doorway to corridor; showing interior and exterior windows, and separated office space; main portion of east wing on main floor; view to south. - Ellsworth Air Force Base, Group Administration & Secure Storage Building, 2372 Westover Avenue, Blackhawk, Meade County, SD

  5. 8. Interior views of unoccupied space; showing large opening into ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Interior views of unoccupied space; showing large opening into lower roofed space, exterior door on south side of building, duct work, and mechanical panel; near center of north side of building; view to south - Ellsworth Air Force Base, Transmitter Building, 200 yards east of County Road, Blackhawk, Meade County, SD

  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. Main characteristics of the Large Space Simulation (LSS)

    NASA Technical Reports Server (NTRS)

    Brinkmann, P. W.

    1984-01-01

    The large space simulator at its European space research and technology center (ESTEC) was implemented. The facility enables mechanical and thermal tests on large satellites. The chamber will be equipped with a collimated solar beam of 6 meter diameter. Infrared equipment is available as alternative or complementary source of thermal radiation. Controlled variation of shroud temperatures can be utilized for thermal testing or temperature cycling of hardware. The basic concept and major design aspects of the facility are presented.

  8. 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.

  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. Automatic in-orbit assembly of large space structures

    NASA Technical Reports Server (NTRS)

    Jacquemin, G. G.

    1979-01-01

    The automated assembly of a large number of components required for the on-orbit erection of large tetrahedral space platforms is described. The assembly machine is a huge jig in which a multitude of mechanisms must operated continuously in the thermo vacuum environment of space and under the control of computers programmed to command every step of each motion. The concepts are presented to determine the most reliable solution. Continuous operation of mechanisms in space presents many unresolved problems, with regard to lubrication of unprotected devices, such as chain drives, which must maintain reasonable positioning tolerances.

  11. Nonterrestrial material processing and manufacturing of large space systems

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G.

    1979-01-01

    Nonterrestrial processing of materials and manufacturing of large space system components from preprocessed lunar materials at a manufacturing site in space is described. Lunar materials mined and preprocessed at the lunar resource complex will be flown to the space manufacturing facility (SMF), where together with supplementary terrestrial materials, they will be final processed and fabricated into space communication systems, solar cell blankets, radio frequency generators, and electrical equipment. Satellite Power System (SPS) material requirements and lunar material availability and utilization are detailed, and the SMF processing, refining, fabricating facilities, material flow and manpower requirements are described.

  12. Space to Think: Large, High-Resolution Displays for Sensemaking

    SciTech Connect

    Andrews, Christopher P.; Endert, Alexander; North, Chris

    2010-05-05

    Space supports human cognitive abilities in a myriad of ways. The note attached to the side of the monitor, the papers spread out on the desk, diagrams scrawled on a whiteboard, and even the keys left out on the counter are all examples of using space to recall, reveal relationships, and think. Technological advances have made it possible to construct large display environments in which space has real meaning. This paper examines how increased space affects the way displays are regarded and used within the context of the cognitively demanding task of sensemaking. A study was conducted observing analysts using a prototype large, high-resolution display to solve an analytic problem. This paper reports on the results of this study and suggests a number of potential design criteria for future sensemaking tools developed for large, high-resolution displays.

  13. Potential large missions enabled by NASA's space launch system

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

  14. 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.

  15. 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.

  16. Large space structures controls research and development at Marshall Space Flight Center: Status and future plans

    NASA Technical Reports Server (NTRS)

    Buchanan, H. J.

    1983-01-01

    Work performed in Large Space Structures Controls research and development program at Marshall Space Flight Center is described. Studies to develop a multilevel control approach which supports a modular or building block approach to the buildup of space platforms are discussed. A concept has been developed and tested in three-axis computer simulation utilizing a five-body model of a basic space platform module. Analytical efforts have continued to focus on extension of the basic theory and subsequent application. Consideration is also given to specifications to evaluate several algorithms for controlling the shape of Large Space Structures.

  17. Research on the control of large space structures

    NASA Technical Reports Server (NTRS)

    Denman, E. D.

    1983-01-01

    The research effort on the control of large space structures at the University of Houston has concentrated on the mathematical theory of finite-element models; identification of the mass, damping, and stiffness matrix; assignment of damping to structures; and decoupling of structure dynamics. The objective of the work has been and will continue to be the development of efficient numerical algorithms for analysis, control, and identification of large space structures. The major consideration in the development of the algorithms has been the large number of equations that must be handled by the algorithm as well as sensitivity of the algorithms to numerical errors.

  18. On the design of large space deployable modular antenna reflectors

    NASA Technical Reports Server (NTRS)

    Ribble, J. W.; Woods, A. A., Jr.

    1981-01-01

    The deployment kinematics, stowing philosophy, and deployment sequencing for large deployable antenna modules were verified. Mesh attachment methods compatible with full scale modules were devised. Parametric studies of large modular reflectors established size, mass, and aperture frequency capabilities for these assemblies. Preliminary studies were made devising means of delivering modules to orbit, and once there, of assembling the modules into complete modular antenna reflectors. The basic feasibility of creating mass efficient modules erectable into large structures in space was established.

  19. 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.

  20. Modal identification experiment design for large space structures

    NASA Technical Reports Server (NTRS)

    Kim, Hyoung M.; Doiron, Harold H.

    1991-01-01

    This paper describes an on-orbit modal identification experiment design for large space structures. Space Station Freedom (SSF) systems design definition and structural dynamic models were used as representative large space structures for optimizing experiment design. Important structural modes of study models were selected to provide a guide for experiment design and used to assess the design performance. A pulsed random excitation technique using propulsion jets was developed to identify closely-spaced modes. A measuremenat location selection approach was developed to estimate accurate mode shapes as well as frequencies and damping factors. The data acquisition system and operational scenarios were designed to have minimal impacts on the SSF. A comprehensive simulation was conducted to assess the overall performance of the experiment design.

  1. A Nestable Tapered Column Concept for Large Space Structures

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    A structural element concept is described which permits achievement of weight critical payloads for space shuttle. These columns are highly efficient structural members which could be the basic building elements for very large, space truss structures. Parametric results are presented which show that untapered cylindrical columns result in volume limited payloads on the space shuttle and that nestable, tapered columns easily eliminate this problem. It is recognized that the tapered column concept belongs to a class of structures which must be assembled in orbit. However, analytical results are presented which indicate that the gain in the amount of structure placed in orbit per launch, is great enough that such a concept should be considered in future systems studies of very large space structures.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Dunbar, W. G.

    1980-02-01

    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.

  4. 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.

  5. 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.

  6. Large-size space laboratory for biological orbit experiments.

    PubMed

    Kondyurin, A

    2001-01-01

    The study of space factors on living systems has great interest and long-term experiments during orbital flight will be important tool for increasing our knowledge. Realization of such experiments is limited by constraints of modern space stations. A new technology of large-size space laboratory for biological experiments has been developed on the basis of polymerization techniques. Using this technique there are no limits of form and size of laboratory for a space station that will permit long term experiments on Earth orbit with plants and animals in sufficient volume for creation of closed self-regulating ecological systems. The technology is based on experiments of the behavior of polymer materials in simulated free space conditions during the reaction of polymerization. The influences of space vacuum, sharp temperature changes and space plasma generated by galactic rays and Sun irradiation on chemical reaction were evaluated in their impact on liquid organic materials in laboratory conditions. The results of our study shows, that the chemical reaction is sensitive to such space factors. But we believe that the technology of polymerization could be used for the creation of space biological laboratories in Earth orbit in the near future.

  7. Use of cryopumps on large space simulation systems

    NASA Technical Reports Server (NTRS)

    Mccrary, L. E.

    1980-01-01

    The need for clean, oil free space simulation systems has demanded the development of large, clean pumping systems. The assurance of optically dense liquid nitrogen baffles over diffusion pumps prevents backstreaming to a large extent, but does not preclude contamination from accidents or a control failure. Turbomolecular pumps or ion pumps achieve oil free systems but are only practical for relatively small chambers. Large cryopumps were developed and checked out which do achieve clean pumping of very large chambers. These pumps can be used as the original pumping system or can be retrofitted as a replacement for existing diffusion pumps.

  8. Reliability issues in active control of large flexible space structures

    NASA Technical Reports Server (NTRS)

    Vandervelde, W. E.

    1983-01-01

    The unreliability of control system components was investigated in our attempt to deal with that problem. This matter is of concern in large space structure control because of the large number of components required to achieve specified performance in some situations, and the long operating period required between maintenance visits. The detection and isolation of component failures during system operation, and algorithms for reconfiguring control systems following detection and isolation of a failure were emphasized.

  9. 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.

  10. 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.

  11. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Innovative telescope architectures for future large space observatories

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Breckinridge, James B.; Lillie, Charles F.; MacEwen, Howard A.; Flannery, Martin R.; Dailey, Dean R.

    2016-10-01

    Over the past few years, we have developed a concept for an evolvable space telescope (EST) that is assembled on orbit in three stages, growing from a 4×12-m telescope in Stage 1, to a 12-m filled aperture in Stage 2, and then to a 20-m filled aperture in Stage 3. Stage 1 is launched as a fully functional telescope and begins gathering science data immediately after checkout on orbit. This observatory is then periodically augmented in space with additional mirror segments, structures, and newer instruments to evolve the telescope over the years to a 20-m space telescope. We discuss the EST architecture, the motivation for this approach, and the benefits it provides over current approaches to building and maintaining large space observatories.

  1. Large Deployable Reflector (LDR) Requirements for Space Station Accommodations

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Effects of material degradation on large space structures dynamic response

    NASA Astrophysics Data System (ADS)

    Perdigao, Alan J.

    1992-08-01

    Composite Large Space Structures (LSS) including booms, planar surfaces, antennas, platforms, and space stations are proposed for use in NASA's Space Station 'Freedom' and the DOD's Global Protection Against Limited Strikes programs. Because of their low mass and high strength and stiffness, composite repetitive lattice structures are ideal for these space applications. LSS will be required to sustain severe environmental effects - radiation, thermal cycling, atomic oxygen bombardment, collision with micrometeoroids and space debris, and hostile actions - and transient operational loads - docking, slewing, manned activities, control system, and the mobile service center - while maintaining strict mission parameters. Platform pointing is one example of these requirements and necessitates tolerances of less than one thousandth of a degree. Over time, material and structural degradation will occur due to environmental effects causing a change in the structure's stiffness and dynamic response. Likely, this structural damage will require immediate repair to restore the LSS to full mission capability. This thesis investigates the dynamic response of one LSS - the NASA Dual-Keel Space Station with 5 meter graphite epoxy erectable truss under one operational load - shuttle docking - and Low Earth Orbit (LEO) environmental conditions, and predicts how the material, structural properties, and dynamic response change over the 20-30 year design life. Results show the effects of material degradation on the station's dynamic response and mission requirements and has applications for NASA and DOD logistics planning for future LSS.

  9. Cheap and near exact CASSCF with large active spaces.

    PubMed

    Smith, James E T; Mussard, Bastien; Holmes, Adam A; Sharma, Sandeep

    2017-10-02

    We use the recently-developed Heat-bath Configuration Interaction (HCI) algorithm as an efficient active-space solver to perform multi-configuration self-consistent field calculations (HCISCF) with large active spaces. We give a detailed derivation of the theory and show that difficulties associated with non-variationality of the HCI procedure can be overcome by making use of the Lagrangian formulation to calculate the HCI relaxed two body reduced density matrix. HCISCF is then used to study the electronic structure of butadiene, pentacene, and Fe-porphyrin. One of the most striking results of our work is that the converged active space orbitals obtained from HCISCF are relatively insensitive to the accuracy of the HCI calculation. This allows us to obtain nearly converged CASSCF energies with an estimated error of less than 1 mHa using the orbitals obtained from the HCISCF procedure in which the integral transformation is the dominant cost. For example, an HCISCF calculation on Fe-Porphyrin model complex with an active space of (44e, 44o) took only 412 seconds per iteration on a single node containing 28 cores, out of which 185 seconds were spent in the HCI calculation and the remaining 227 seconds were mainly used for integral transformation. Finally, we also show that active-space orbitals can be optimized using HCISCF to substantially speed up the convergence of the HCI energy to the Full CI limit because HCI is not invariant to unitary transformations within the active space.

  10. Future large space systems opportunities: A case for space-to-space power?. [spacecraft power supplies microwave and laser transmission

    NASA Technical Reports Server (NTRS)

    Garrett, L. B.; Hook, W. R.

    1978-01-01

    Applications and options for beaming power to near-earth space users from a central space power platform are examined. The cost effectiveness of on-board versus remote power transfer is examined for orbital transfer propulsion systems. Performance characteristics are projected for advanced power generation, transmission, and receiver systems for the 1990's. Major technological development needs are identified with particular emphasis on large space systems technology.

  11. Construction in space: A proposed experiment in support of the space solar power concept and other large space systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The conceptual equipment and techniques for fabricating and assembling a ladder-like structure of triangular cross section trusses suitable for mounting solar cell arrays are described. The detail information is presented in the context of a proposed experiment to be conducted from the shuttle in the 1980-84 time period as an early experiment in the development of techniques for the construction of large space structures that would be required for space solar power stations and other large systems.

  12. 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.

  13. Design of optical systems for large space telescopes

    NASA Astrophysics Data System (ADS)

    Malamed, Evgeny R.; Sokolsky, M. N.

    1995-09-01

    On the basis of long-term experience of LOMO PLC in creating large optical systems for ground and space telescopes, with diameter of primary mirror from 1 to 6 meters, the following issues should be considered: principles of constructing optical systems for space telescopes and selecting their optimum design in respect of dimensions/mass and performance criteria; ensuring the fulfillment of image quality requirements in the process of manufacturing optical systems for controlling ground telescope elements in operating conditions; providing automatic adjustment of telescope secondary mirror, automatic focusing, interferometric control of image quality by means of stellar interferometer with radial shift and internal control with Gartman's test. Description of space telescope equipped with primary mirror of diameter 1.5 m, manufactured in LOMO PLC, is given.

  14. 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

  15. Space Assembly of Large Structural System Architectures (SALSSA)

    NASA Technical Reports Server (NTRS)

    Dorsey, John T.; Watson, Judith J.

    2016-01-01

    Developing a robust capability for Space Assembly of Large Spacecraft Structural System Architectures (SALSSA) has the potential to drastically increase the capabilities and performance of future space missions and spacecraft while significantly reducing their cost. Currently, NASA architecture studies and space science decadal surveys identify new missions that would benefit from SALSSA capabilities, and the technologies that support SALSSA are interspersed throughout the fourteen NASA Technology Roadmaps. However, a major impediment to the strategic development of cross-cutting SALSSA technologies is the lack of an integrated and comprehensive compilation of the necessary information. This paper summarizes the results of a small study that used an integrated approach to formulate a SALSSA roadmap and associated plan for developing key SALSSA technologies.

  16. Approximate likelihood for large irregularly spaced spatial data

    PubMed Central

    Fuentes, Montserrat

    2008-01-01

    SUMMARY Likelihood approaches for large irregularly spaced spatial datasets are often very difficult, if not infeasible, to implement due to computational limitations. Even when we can assume normality, exact calculations of the likelihood for a Gaussian spatial process observed at n locations requires O(n3) operations. We present a version of Whittle’s approximation to the Gaussian log likelihood for spatial regular lattices with missing values and for irregularly spaced datasets. This method requires O(nlog2n) operations and does not involve calculating determinants. We present simulations and theoretical results to show the benefits and the performance of the spatial likelihood approximation method presented here for spatial irregularly spaced datasets and lattices with missing values. We apply these methods to estimate the spatial structure of sea surface temperatures (SST) using satellite data with missing values. PMID:19079638

  17. 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.

  18. 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.

  19. 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.

  20. Recent advances in structural dynamics of large space structures

    NASA Astrophysics Data System (ADS)

    Pinson, Larry D.

    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 is summarized.

  1. Optimal experiment design for identification of large space structures

    NASA Technical Reports Server (NTRS)

    Bayard, D. S.; Hadaegh, F. Y.; Meldrum, D. R.

    1988-01-01

    The optimal experiment design for on-orbit identification of modal frequency and damping parameters in large flexible space structures is discussed. The main result is a separation principle for D-optimal design which states that under certain conditions the sensor placement problem is decoupled from the input design problem. This decoupling effect significantly simplifies the overall optimal experiment design determination for large MIMO structural systems with many unknown modal parameters. The error from using the uncoupled design is estimated in terms of the inherent damping of the structure. A numerical example is given, demonstrating the usefulness of the simplified criteria in determining optimal designs for on-orbit Space Station identification experiments.

  2. Lagrangian space consistency relation for large scale structure

    SciTech Connect

    Horn, Bart; Hui, Lam; Xiao, Xiao E-mail: lh399@columbia.edu

    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 and Riotto and Peloso and 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.

  3. Identification of large space structures on orbit : A survey

    NASA Technical Reports Server (NTRS)

    Denman, Eugene E.; Hasselman, T. K.; Juang, Jer-Nan; Junkins, John L.; Kamat, Manohar; Sun, C. T.; Udwadia, Firdaus; Venkayya, V. R.; Kippel, Edward; Dale, Eric

    1988-01-01

    The Task Committee on Methods for Identification of Large Structures in Space was founded in Jul. 1984. The charter of the committee was to prepare a state-of-the-art report on methods of system identification applicable to large space structures (LSS). Funding to support preparation of the report was received in Aug. 1985 from the Air Force Rocket Propulsion Laboratory (now the Air Force Astronautics Laboratory), in the form of a contract to the ASCE. The report was completed, and published by AFRPL in Sep. 1986. The Task Committee consisted of ten members, including ASCE and AFRPL representatives. The membership represented Government, Industry, and Universities, and consisted of electrical, mechanical, and civil engineers, with backgrounds in Structural Dynamics, Optimization, and Controls. An effort was made to use consistent terminology and notation throughout the report which would be compatible with the terminology used in both the structures and controls communities.

  4. Positive position feedback control for large space structures

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Caughey, T. K.

    1987-01-01

    A new technique for vibration suppression in large space structures is investigated in laboratory experiments on a thin cantilever beam. This technique, called Positive Position Feedback, makes use of generalized displacement measurements to accomplish vibration suppression. Several features of Positive Position Feedback make it attractive for the large space structure control environment: The realization of the controller is simple and straightforward. Global stability conditions can be derived which are independent of the dynamical characteristics of the structure being controlled, i.e., all spillover is stabilizing. The method cannot be destabilized by finite actuator dynamics, and the technique is amenable to a strain-based sensing approach. The experiments control the first six bending modes of a cantilever beam, and make use of piezoelectric materials for actuators and sensors, simulating a piezoelectric active-member. The modal damping ratios are increased by factors ranging from 2 to 130.

  5. Integrated structural electromagnetic optimization of large space antenna reflectors

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Adelman, H. 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 part 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.

  6. 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.

  7. 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.

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

    NASA Technical Reports Server (NTRS)

    Humes, Donald H.

    1991-01-01

    The distribution around the Long Duration Exposure Facility (LDEF) of 532 large craters in the Al plates from the Meteoroid and Space Debris Impact Experiment (S0001) is discussed along with 74 additional large craters in Al plates donated to the Meteoroid and Debris Special Investigation Group by other LDEF experimenters. The craters are 0.5 mm in diameter and larger. Crater shape is discussed. The number of craters and their distribution around the spacecraft are compared with values predicted with models of the meteoroid environment and the manmade orbital debris environment.

  9. 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.

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

    NASA Technical Reports Server (NTRS)

    Humes, Donald H.

    1991-01-01

    The distribution around the Long Duration Exposure Facility (LDEF) of 532 large craters in the Al plates from the Meteoroid and Space Debris Impact Experiment (S0001) is discussed along with 74 additional large craters in Al plates donated to the Meteoroid and Debris Special Investigation Group by other LDEF experimenters. The craters are 0.5 mm in diameter and larger. Crater shape is discussed. The number of craters and their distribution around the spacecraft are compared with values predicted with models of the meteoroid environment and the manmade orbital debris environment.

  11. 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.

  12. 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.

  13. Simulation and experiment for large scale space structure

    NASA Astrophysics Data System (ADS)

    Sun, Hongbo; Zhou, Jian; Zha, Zuoliang

    2013-04-01

    The future space structures are relatively large, flimsy, and lightweight. As a result, they are more easily affected or distortion by space environments compared to other space structures. This study examines the structural integrity of a large scale space structure. A new design of transient temperature field analysis method of the developable reflector on orbit environment is presented, which simulates physical characteristic of developable antenna reflector with a high precision. The different kinds of analysis denote that different thermal elastic characteristics of different materials. The three-dimension multi-physics coupling transient thermal distortion equations for the antenna are founded based on the Galerkins method. For a reflector on geosynchronous orbit, the transient temperature field results from this method are compared with these from NASA. It follows from the analysis that the precision of this method is high. An experimental system is established to verify the control mechanism with IEBIS and thermal sensor technique. The shape control experiments are finished by measuring and analyzing developable tube. Results reveal that the temperature levels of the developable antenna reflector alternate greatly in the orbital period, which is about ±120° when considering solar flux ,earth radiating flux and albedo scattering flux.

  14. Simplified thermal estimation techniques for large space structures

    NASA Technical Reports Server (NTRS)

    Brogren, E. W.; Barclay, D. L.; Straayer, J. W.

    1977-01-01

    A tool for making rapid estimates of the response of space structures to thermal environments encountered in earth orbits is provided for the designer of these structures. Charts giving heating rates and temperatures for certain typical large spacecraft structural elements are provided. Background information for spacecraft thermal design considerations is presented. Environments, requirements, thermal control techniques, design guidelines, and approaches available for more detailed thermal response analysis are discussed.

  15. 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.

  16. Accuracy potentials for large space antenna reflectors with passive structure

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1982-01-01

    Analytical results indicate that a careful selection of materials and truss design, combined with accurate manufacturing techniques, can result in very accurate surfaces for large space antennas. The purpose of this paper is to examine these relationships for various types of structural configurations. Comparisons are made of the accuracy achievable by truss- and dome-type structures for a wide range of diameter and focal length of the antenna and wavelength of the radiated signal.

  17. 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.

  18. 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.

  19. 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.

  20. Measuring large scale space perception in literary texts

    NASA Astrophysics Data System (ADS)

    Rossi, Paolo

    2007-07-01

    A center and radius of “perception” (in the sense of environmental cognition) can be formally associated with a written text and operationally defined. Simple algorithms for their computation are presented, and indicators for anisotropy in large scale space perception are introduced. The relevance of these notions for the analysis of literary and historical records is briefly discussed and illustrated with an example taken from medieval historiography.

  1. 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.

  2. Large-scale quantization from local correlations in space plasmas

    NASA Astrophysics Data System (ADS)

    Livadiotis, George; McComas, David J.

    2014-05-01

    This study examines the large-scale quantization that can characterize the phase space of certain physical systems. Plasmas are such systems where large-scale quantization, ħ*, is caused by Debye shielding that structures correlations between particles. The value of ħ* is constant—some 12 orders of magnitude larger than the Planck constant—across a wide range of space plasmas, from the solar wind in the inner heliosphere to the distant plasma in the inner heliosheath and the local interstellar medium. This paper develops the foundation and advances the understanding of the concept of plasma quantization; in particular, we (i) show the analogy of plasma to Planck quantization, (ii) show the key points of plasma quantization, (iii) construct some basic quantum mechanical concepts for the large-scale plasma quantization, (iv) investigate the correlation between plasma parameters that implies plasma quantization, when it is approximated by a relation between the magnetosonic energy and the plasma frequency, (v) analyze typical space plasmas throughout the heliosphere and show the constancy of plasma quantization over many orders of magnitude in plasma parameters, (vi) analyze Advanced Composition Explorer (ACE) solar wind measurements to develop another measurement of the value of ħ*, and (vii) apply plasma quantization to derive unknown plasma parameters when some key observable is missing.

  3. On the possibility of large axion moduli spaces

    SciTech Connect

    Rudelius, Tom

    2015-04-01

    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 [1] 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 [2], so it likely applies not only to axions in string theory, but also to axions in any consistent theory of quantum gravity.

  4. 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.

  5. 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.

  6. HIV-1 Nucleocapsid Protein Switches the Pathway of TAR RNA/DNA Annealing from Loop-Loop “Kissing” to “Zipper”

    PubMed Central

    Vo, My-Nuong; Barany, George; Rouzina, Ioulia; Musier-Forsyth, Karin

    2009-01-01

    Summary The chaperone activity of human immunodeficiency virus type 1 (HIV-1) nucleocapsid protein (NC) facilitates multiple nucleic acid rearrangements that are critical for reverse transcription of the single-stranded RNA genome into double-stranded DNA. Annealing of the trans-activation response element (TAR) RNA hairpin to a complementary TAR DNA hairpin is an essential step in the minus-strand transfer step of reverse transcription. Previously, we used truncated 27-nucleotide (nt) mini-TAR RNA and DNA constructs to investigate this annealing reaction pathway in the presence and absence of HIV-1 NC. In this work, full-length 59-nt TAR RNA and TAR DNA constructs were used to systematically study TAR hairpin annealing kinetics. In the absence of NC, full-length TAR hairpin annealing is ∼10-fold slower than mini-TAR annealing. Similar to mini-TAR annealing, the reaction pathway for TAR in the absence of NC involves the fast formation of an unstable “kissing” loop intermediate, followed by a slower conversion to an extended duplex. NC facilitates the annealing of TAR by ∼105-fold by stabilizing the bimolecular intermediate (∼104-fold) and promoting the subsequent exchange reaction (∼10-fold). In contrast to the mini-TAR annealing pathway, wherein NC-mediated annealing can initiate through both loop-loop kissing and a distinct “zipper” pathway involving nucleation at the 3′/5′ terminal ends, full-length TAR hairpin annealing switches predominantly to the zipper pathway in the presence of saturated NC. PMID:19154737

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Robust design of distributed controllers for large flexible space structures

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.

    1988-01-01

    Independent Modal Space Control (IMSC) method avoids control spillover generated by conventional control schemes such as Coupled Modal Control by decoupling the large flexible space structure into independent subsystems of second order and controlling each mode independently. The IMSC implementation requires that the number of actuators be equal to that of modeled modes, which is in general very huge. Consequently the number of required actuators is unrealizable. Two methods are proposed for the implementation of IMSC with reduced number of actuators. In the first method, the first m modes are optimized, leaving the last (n-m) modes unchanged. In the second method, generalized inverse matrices are employed to design the feedback controller so that the control scheme is suboptimal with respect to IMSC. The performance of the proposed methods is tested by performing computer simulation on a simply support beam. Simulation results are presented and discussed.

  14. 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.

  15. 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.

  16. Development of television tubes for the large space telescope

    NASA Technical Reports Server (NTRS)

    Lowrance, J. L.; Zucchino, P.

    1971-01-01

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

  17. 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.

  18. An Improved Wavefront Control Algorithm for Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Basinger, Scott A.; Redding, David C.

    2008-01-01

    Wavefront sensing and control is required throughout the mission lifecycle of large space telescopes such as James Webb Space Telescope (JWST). When an optic of such a telescope is controlled with both surface-deforming and rigid-body actuators, the sensitivity-matrix obtained from the exit pupil wavefront vector divided by the corresponding actuator command value can sometimes become singular due to difference in actuator types and in actuator command values. In this paper, we propose a simple approach for preventing a sensitivity-matrix from singularity. We also introduce a new "minimum-wavefront and optimal control compensator". It uses an optimal control gain matrix obtained by feeding back the actuator commands along with the measured or estimated wavefront phase information to the estimator, thus eliminating the actuator modes that are not observable in the wavefront sensing process.

  19. 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.

  20. On passive damping mechanisms in large space structures

    NASA Technical Reports Server (NTRS)

    Ashley, H.

    1982-01-01

    The significance is explained of even tiny amounts of passive energy dissipation to ensure successful stabilization of large, flexible space structures. Study of scale effects on various mechanisms indicates that modal damping ratios are likely to decrease as size increases in a family of similar structures. Paper focuses on thermal dissipation induced by strain gradients during vibration of monolithic configurations. Past work and the expected magnitudes of this damping are reviewed, along with reasons why it is, to some degree, under the designer's control. In the search for the highest practical values, unidirectional metallic composites and other arrangements are examined

  1. 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.

  2. 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.

  3. 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.

  4. Optimal member damper controller design for large space structures

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    Consideration is given to the selection of velocity feedback gains for individual dampers for the members of a structurally controlled large flexible space structure. The problem is formulated as an optimal output feedback regulator problem, and necessary conditions are derived for minimizing a quadratic performance function. The diagonal nature of the gain matrix is taken into account, along with knowledge of noise covariances. It is pointed out that the method presented offers a systematic approach to the design of a class of controllers for enhancing structural damping, which have significant potential if used in conjunction with a reduced-order optimal controller for rigid-body modes and selected structural modes.

  5. An Expert System Approach to Large Space Systems Control

    DTIC Science & Technology

    1988-10-01

    ISPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION Of appil ,k) FOSR F49620-87- C --0105 8¢. ADDRESS (CRtY, Stat...oo...0 - An Expert System Approach To Large Space Systems Control Octobe 1988Accession For NTIS R& DTIC TAB C . GartrmII Unannounced E W...4.4.1 Case A: I Newton Harmonic Wave with a Frequency of 0.14 Hz 4-12 4.4.2 Case B: 1 Newton Impulse at x = 2.5 m 4-13 4.4.3 Case C : Traveling Wave with

  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. On passive damping mechanisms in large space structures

    NASA Technical Reports Server (NTRS)

    Ashley, H.

    1982-01-01

    The significance is explained of even tiny amounts of passive energy dissipation to ensure successful stabilization of large, flexible space structures. Study of scale effects on various mechanisms indicates that modal damping ratios are likely to decrease as size increases in a family of similar structures. Paper focuses on thermal dissipation induced by strain gradients during vibration of monolithic configurations. Past work and the expected magnitudes of this damping are reviewed, along with reasons why it is, to some degree, under the designer's control. In the search for the highest practical values, unidirectional metallic composites and other arrangements are examined

  8. 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.

  9. Electrical rotary joint apparatus for large space structures

    NASA Technical Reports Server (NTRS)

    Belew, R. R.; Boehme, R. J. (Inventor)

    1981-01-01

    A structural array and electrical rotary joint for transmitting an electrical power between large space structures having relative rotational movement is disclosed which includes large support framework structures which rotate relative to one another about a common axis of rotation. A rotary interface joint is defined between the structures. A cylindrical hub member is carried by one structure and a cylindrical hub member is carried by a support structure with a third hub member being concentrically within a fourth hub member for relative rotation. Tension connecting cables connect hub members with their associated outer structures whereby relative rotational movement between the structures is transmitted to the cylindrical hub members for unitary motion therewith. Electrical conductor brush members are carried by one hub and electrical contact rings are carried by another hub member in sliding electrical contact with the brushes for transmission of electrical power during relative rotational movement between the two support structures.

  10. 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.

  11. 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.

  12. Lightweight optical barrel assembly structures for large deployable space telescopes

    NASA Astrophysics Data System (ADS)

    Warren, Peter A.; Silver, Mark J.; Dobson, Benjamin J.

    2009-08-01

    Future space based telescopes will need apertures and focal lengths that exceed the dimensions of the launch vehicle shroud. In addition to deploying the primary mirror and secondary mirror support structure, these large telescopes must also deploy the stray light and thermal barriers needed to ensure proper telescope performance. The authors present a deployable light and thermal optical barrel assembly approach for a very large telescope with a variable sun angle and fast slew rate. The Strain Energy Deployable Optical Barrel Assembly (SEDOBA) uses elastic composite hinges to power the deployment of a hierarchical truss structure that supports the thermal and stray light shroud material that form the overall system. The paper describes the overall design approach, the key component technologies, and the design and preliminary testing of a self deploying scale model prototype.

  13. Integrated controls-structures optimization of a large space structure

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.; Walsh, Joanne L.; Sandridge, Chris A.; Haftka, Raphael T.

    1990-01-01

    A technique for the simultaneous optimization of structural and control elements of a large space structure is developed and demonstrated for a test problem, the NASA COFS-I Mast Flight System. General-purpose control and structural-analysis codes are applied directly to a large detailed model, with realistic objective and constraint functions. The steps in the process (structural optimization, control optimization, and system coordination) are described and illustrated with diagrams; the numerical implementation (using different computers for different steps) is discussed; and results showing significant design improvements in three COFS-I configurations are presented in graphs. When the weights of both structure and power-generating equipment are taken into account, a 40-bay truss design is found to be better than designs with 42 or 44 bays.

  14. 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.

  15. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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. In addition to the science opportunities, this talk includes a description of the instruments, the opportunities for guest investigators, and the mission status.

  16. A fine pointing system for the large space telescope

    NASA Technical Reports Server (NTRS)

    Schiehlen, W. O.

    1973-01-01

    The large space telescope (LST) developed by NASA requires ultrahigh pointing stability within 0.0005 arc sec rms. A fine guidance system is proposed to body-point the entire spacecraft within this limit. The spacecraft is modeled as a rigid body having reaction wheel actuators and subject to gravitational and magnetic disturbance torques. The fine guidance sensor is cluttered with electronic noise. The disturbance accommodation standard deviation optimal controller (DASOC) is designed to be optimal with respect to the transient and the steady state response to noise, whereas the steady state response to deterministic external torques is exactly zero. Compared with conventional controllers, the fine guidance system with the DASOC offers as much as a factor of 30 improvement in pointing stability, resulting in an optimal performance of nearly 0.0001 arc sec rms. Thus, the required pointing stability can easily be obtained, and a large margin remains for the compensation of possibile deteriorations.

  17. The LATT way towards large active primaries for space telescopes

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Arcidiacono, Carmelo; Xompero, Marco; Lisi, Franco; Riccardi, Armando; Biasi, Roberto; Patauner, Christian; Gallieni, Daniele; Lazzarini, Paolo; Tintori, Matteo; d'Amato, Francesco; Pucci, Mauro; Duò, Fabrizio; Vettore, Christian; Zuccaro Marchi, Alessandro

    2016-07-01

    The Large Aperture Telescope Technology (LATT) goes beyond the current paradigm of future space telescopes, based on a deformable mirror in the pupil relay. Through the LATT project we demonstrated the concept of a low-weight active primary mirror, whose working principle and control strategy benefit from two decades of advances in adaptive optics for ground-based telescopes. We developed a forty centimeter spherical mirror prototype, with an areal density lower than 17 kg/m2, controlled through contactless voice coil actuators with co-located capacitive position sensors. The prototype was subjected to thermo-vacuum, vibration and optical tests, to push its technical readiness toward level 5. In this paper we present the background and the outcomes of the LATT activities under ESA contract (TRP programme), exploring the concept of a lightweight active primary mirror for space telescopes. Active primaries will open the way to very large segmented apertures, actively shaped, which can be lightweight, deployable and accurately phased once in flight.

  18. Finite element structural model of a large, thin, completely free, flat plate. [for large space structures

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    A finite element structural model of a 30.48 m x 30.48 m x 2.54 mm completely free aluminum plate is described and modal frequencies and mode shape data for the first 44 modes are presented. An explanation of the procedure for using the data is also presented. The model should prove useful for the investigation of controller design approaches for large flexible space structures.

  19. Lyot coronagraph design study for large, segmented space telescope apertures

    NASA Astrophysics Data System (ADS)

    Zimmerman, Neil T.; N'Diaye, Mamadou; St. Laurent, Kathryn E.; Soummer, Rémi; Pueyo, Laurent; Stark, Christopher C.; Sivaramakrishnan, Anand; Perrin, Marshall; Vanderbei, Robert J.; Kasdin, N. J.; Shaklan, Stuart; Carlotti, Alexis

    2016-07-01

    Recent efforts combining the optimization techniques of apodized pupil Lyot coronagraphs (APLC) and shaped pupils have demonstrated the viability of a binary-transmission mask architecture for extremely high contrast (10-10) exoplanet imaging. We are now building on those innovations to carry out a survey of Lyot coronagraph performance for large, segmented telescope apertures. These apertures are of the same kind under considera- tion for NASA's Large UV/Optical/IR (LUVOIR) observatory concept. To map the multi-dimensional design parameter space, we have developed a software toolkit to manage large sets of mask optimization programs and execute them on a computing cluster. Here we summarize a preliminary survey of 500 APLC solutions for 4 reference hexagonal telescope apertures. Several promising designs produce annular, 10-10 contrast dark zones down to inner working angle 4λ0=D over a 15% bandpass, while delivering a half-max PSF core throughput of 18%. We also report our progress on devising solutions to the challenges of Lyot stop alignment/fabrication tolerance that arise in this contrast regime.

  20. Approximation of the optimal compensator for a large space structure

    NASA Technical Reports Server (NTRS)

    Mackay, M. K.

    1983-01-01

    This paper considers the approximation of the optimal compensator for a Large Space Structure. The compensator is based upon a solution to the Linear Stochastic Quadratic Regulator problem. Colocation of sensors and actuators is assumed. A small gain analytical solution for the optimal compensator is obtained for a single input/single output system, i.e., certain terms in the compensator can be neglected for sufficiently small gain. The compensator is calculated in terms of the kernel to a Volterra integral operator using a Neumann series. The calculation of the compensator is based upon the C sub 0 semigroup for the infinite dimensional system. A finite dimensional approximation of the compensator is, therefore, obtained through analysis of the infinite dimensional compensator which is a compact operator.

  1. Free oscillations of a large drop in space

    NASA Technical Reports Server (NTRS)

    Jacobi, N.; Tagg, R. P.; Kendall, J. M.; Elleman, D. D.; Wang, T. G.

    1979-01-01

    In preparation for forthcoming studies on materials processing in space, techniques and equipment are being developed for the deployment and control of large globules of liquid in a zero-g environment. This paper first presents a theoretical analysis of the intense sound field within an enclosure by which positioning forces, torques, and temporal perturbations may be applied to a sample. Procedures for digital analysis of photographic records of the sample motion are described. Results on the mean and oscillatory motion of a 2.5 cm diameter water drop during the flight of a SPAR rocket are given. In particular, spectral analysis shows that the drop oscillates at several frequencies. Identification with theoretically expected modes is made for some of the spectral lines.

  2. 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.

  3. Verification of large beam-type space structures

    NASA Technical Reports Server (NTRS)

    Shih, Choon-Foo; Chen, Jay C.; Garba, John A.

    1987-01-01

    The verification approach of large beam type space structures is verified. The proposed verification approach consists of two parts. The first part is to remove the gravity effect on the tested substructure and to identify the on-orbit dynamic characteristics of the substructure by using the measurements of the ground test. A scaling law is also established to define the critical length of the structure which can be tested in 1-g field without incurring a buckling problem. The second part is to develop an adequate scaling law to extrapolate the dynamic characteristics of the prototype structure by using results from the substructure. The verification approaches are demonstrated on two typical structural configurations, the feed support structure of a wrap-rip antenna and a candidate shuttle flight experiment. The results indicate that it is practical to verify the on-orbit dynamic characteristics of these structures by using the proposed approach.

  4. 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.

  5. Advances in Mechanical Architectures of Large Precision Space Apertures

    NASA Astrophysics Data System (ADS)

    Datashvili, Leri; Maghaldadze, Nikoloz; Endler, Stephan; Pauw, Julian; He, Peng; Baier, Horst; Ihle, Alexander; Santiago Prowlad, Julian

    2014-06-01

    Recent advances in development of mechanical architectures of large deployable reflectors (LDRs) through the projects of the European Space Agency are addressed in this paper. Two different directions of LDR architectures are being investigated and developed at LSS and LLB. These are LDRs with knitted metal mesh and with flexible shell-membrane reflecting surfaces. The first direction is matured and required advancing of the novel architecture of the supporting structure that provides deployment and final shape accuracy of the metal mesh is underway. The second direction is rather new and its current development stage is focused on investigations of dimensional stability of the flexible shell-membrane reflecting surface. In both directions 5 m diameter functional models will be built to demonstrate achieved performances, which shall prepare the basis for further improvement of their technology readiness levels.

  6. 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.

  7. 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.

  8. Characterization of the bending stiffness of large space structure joints

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    1989-01-01

    A technique for estimating the bending stiffness of large space structure joints is developed and demonstrated for an erectable joint concept. Experimental load-deflection data from a three-point bending test was used as input to solve a closed-form expression for the joint bending stiffness which was derived from linear beam theory. Potential error sources in both the experimental and analytical procedures are identified and discussed. The bending stiffness of a mechanically preloaded erectable joint is studied at three applied moments and seven joint orientations. Using this technique, the joint bending stiffness was bounded between 6 and 17 percent of the bending stiffness of the graphite/epoxy strut member.

  9. Free oscillations of a large drop in space

    NASA Technical Reports Server (NTRS)

    Jacobi, N.; Tagg, R. P.; Kendall, J. M.; Elleman, D. D.; Wang, T. G.

    1979-01-01

    In preparation for forthcoming studies on materials processing in space, techniques and equipment are being developed for the deployment and control of large globules of liquid in a zero-g environment. This paper first presents a theoretical analysis of the intense sound field within an enclosure by which positioning forces, torques, and temporal perturbations may be applied to a sample. Procedures for digital analysis of photographic records of the sample motion are described. Results on the mean and oscillatory motion of a 2.5 cm diameter water drop during the flight of a SPAR rocket are given. In particular, spectral analysis shows that the drop oscillates at several frequencies. Identification with theoretically expected modes is made for some of the spectral lines.

  10. 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.

  11. 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.

  12. 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.

  13. Active disturbance rejection in large flexible space structures

    NASA Technical Reports Server (NTRS)

    Parlos, Alexander G.; Sunkel, John W.

    1990-01-01

    The design of an active control law for the rejection of persistent disturbances, in large space structures is presented. The control system design approach is based on a deterministic model of the disturbances and it optimizes the magnitude of the disturbance that the structure can tolerate without violating certain predetermined constraints. In addition to closed-loop stability, the explicit treatment of state, control, and control rate constraints, such as structural displacement and control actuator effort, guarantees that the final design will exhibit desired performance characteristics. The technique is applied to a simple two-bay truss structure, and its response is compared with that obtained using a linear-quadratic-Gaussian/loop-transfer-recovery (LQG/LTR) compensator. Preliminary results indicate that the proposed control system can reject persistent disturbances of greater magnitude by utilizing most of the available control, while limiting the structural displacements to within desired tolerances.

  14. 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.

  15. 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.

  16. 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.

  17. Structural identification and damage assessment of large space structures

    NASA Technical Reports Server (NTRS)

    Nelson, Richard B.; Fourney, Michael E.

    1988-01-01

    Two different methods are proposed for identifying the structural properties of large orbiting space structures under ordinary service loads, and for assessing potential damage due to impact or other extreme loadings. It is shown that the behavior of a structure in a weightless environment is nonlinear due to unloaded or lightly loaded connections, an effect which not only complicates structural control, but makes the problem of system identification more difficult than for ground based systems. Both proposed methods assume that the structure is subjected to loads imposed by prescribed self stressing systems sufficient to produce repeatable internal force systems in the structure. The first method is based on statical response and requires a survey of structural displacements produced by the self stressing systems. The displacements do not have to be determined completely (i.e., in three directions at each connection), but more displacement information produces more accurate structural stiffness information. It is anticipated that displacement measurements will be taken using on-board laser measurement devices. The second technique employs dynamic stress wave measurement techniques using on-board loading devices and strain gages to track stress wave propagation through the space structure. This approach, which is in its early stages of development, relies on an analysis of transit times of impulsive stress waves and changes in transit times and wave forms due to changes in structural parameters.

  18. Human exposure to large solar particle events in space

    NASA Astrophysics Data System (ADS)

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

    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/cm2) and storm shelter (20 g/cm2) 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.

  19. Structural identification and damage assessment of large space structures

    NASA Technical Reports Server (NTRS)

    Nelson, Richard B.; Fourney, Michael E.

    1988-01-01

    Two different methods are proposed for identifying the structural properties of large orbiting space structures under ordinary service loads, and for assessing potential damage due to impact or other extreme loadings. It is shown that the behavior of a structure in a weightless environment is nonlinear due to unloaded or lightly loaded connections, an effect which not only complicates structural control, but makes the problem of system identification more difficult than for ground based systems. Both proposed methods assume that the structure is subjected to loads imposed by prescribed self stressing systems sufficient to produce repeatable internal force systems in the structure. The first method is based on statical response and requires a survey of structural displacements produced by the self stressing systems. The displacements do not have to be determined completely (i.e., in three directions at each connection), but more displacement information produces more accurate structural stiffness information. It is anticipated that displacement measurements will be taken using on-board laser measurement devices. The second technique employs dynamic stress wave measurement techniques using on-board loading devices and strain gages to track stress wave propagation through the space structure. This approach, which is in its early stages of development, relies on an analysis of transit times of impulsive stress waves and changes in transit times and wave forms due to changes in structural parameters.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Large Scale System Safety Integration for Human Rated Space Vehicles

    NASA Astrophysics Data System (ADS)

    Massie, Michael J.

    2005-12-01

    Since the 1960s man has searched for ways to establish a human presence in space. Unfortunately, the development and operation of human spaceflight vehicles carry significant safety risks that are not always well understood. As a result, the countries with human space programs have felt the pain of loss of lives in the attempt to develop human space travel systems. Integrated System Safety is a process developed through years of experience (since before Apollo and Soyuz) as a way to assess risks involved in space travel and prevent such losses. The intent of Integrated System Safety is to take a look at an entire program and put together all the pieces in such a way that the risks can be identified, understood and dispositioned by program management. This process has many inherent challenges and they need to be explored, understood and addressed.In order to prepare truly integrated analysis safety professionals must gain a level of technical understanding of all of the project's pieces and how they interact. Next, they must find a way to present the analysis so the customer can understand the risks and make decisions about managing them. However, every organization in a large-scale project can have different ideas about what is or is not a hazard, what is or is not an appropriate hazard control, and what is or is not adequate hazard control verification. NASA provides some direction on these topics, but interpretations of those instructions can vary widely.Even more challenging is the fact that every individual/organization involved in a project has different levels of risk tolerance. When the discrete hazard controls of the contracts and agreements cannot be met, additional risk must be accepted. However, when one has left the arena of compliance with the known rules, there can be no longer be specific ground rules on which to base a decision as to what is acceptable and what is not. The integrator must find common grounds between all parties to achieve

  6. 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.

  7. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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 opportunities for guest investigators, and the mission status.

  8. 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.

  9. The Gamma-Ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, GLAST will open a new and important window on a wide variety of high-energy 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 signals of hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to the science opportunities, this talk includes a brief description of the instruments, the opportunities for guest investigators, and the mission status.

  10. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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 opportunities for guest investigators, and the mission status.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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

  16. Modification of the ionosphere by large space vehicles

    NASA Astrophysics Data System (ADS)

    Mendillo, M.

    Not Available Copyright 1980 by Michael Mendillo. Extracted from ``Space Systems and their Interactions with Earth's Space Environment'' (Vol. 71 of ``Progress in Astronautics and Aeronautics'', eds. H.B. Garret and C.P. Pike), 1980

  17. Future large-aperture UVOIR space observatory: reference designs

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Our joint NASA GSFC/JPL/MSFC and STScI study team has used community-developed science goals to derive mission needs, design parameters, notional instruments, and candidate mission architectures for a future large-aperture, noncryogenic UVOIR space observatory. We describe the feasibility assessment of system dynamic stability that supports coronagraphy. The observatory is in a Sun-Earth L2 orbit, which provides a stable thermal environment and excellent field of regard. Reference designs include a 36-segment 9.2-m aperture telescope that stows within a 5-m diameter launch vehicle fairing. This paper presents results from the latest cycle of integrated modeling through January 2016. The latest findings support the feasibility of secondary mirror support struts with a thickness on the order of an inch. Thin struts were found not to have a significant negative effect on wavefront error stability. Struts with a width as small as 1 in. may benefit some coronagraph designs by allowing more optical throughput.

  18. 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.

  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. 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.

  1. Cryogenic techniques for large superconducting magnets in space

    SciTech Connect

    Green, M.A.

    1988-12-01

    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. Both of these methods will extend the ASTROMAG cryogenic operating life from 2 years to almost 4 years. 14 refs., 8 figs., 4 tabs.

  2. Upgrade Of ESA Large Space Simulator For Providing Mercury Environment

    NASA Astrophysics Data System (ADS)

    Messing, Rene; Popovitch, Alexandre; Tavares, Andre; Sablerolle, Steven

    2012-07-01

    When orbiting Mercury, the BepiColombo spacecraft will have to survive direct sunlight ten times more intense than in the Earth's vicinity, and the infrared radiation from the planet's surface, which exceeds 400°C at its hottest point. In order to simulate the environment for testing the spacecraft in thermal conditions as representative as possible to those it will meet in Mercury’s orbit, it was required to modify the ESTEC Large Space Simulator (LSS) for providing a 10 Solar Constant (SC) illumination. The following test facility adaptations are described: - Investigate powerful lamps - Configure the LSS mirror from 6m to a 2.7m-diameter light beam - Develop a fast flux mapping system - Procure a 10 SC absolute radiometer standard - Replace the sun simulator flux control sensors - Add a dedicated shroud to absorb the high flux - Add a levelling table to adjust heat pipes - Add infra-red cameras for contactless high temperature measurements. The facility performance during the test of one of the BepiColombo modules is reviewed.

  3. 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.

  4. Methodology for Evaluating Modular Assembly of Large Space Platforms

    NASA Astrophysics Data System (ADS)

    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. The physical model includes alternative module design characteristics, assembly time scenarios, alternative work systems (human, robotic), and infrastructures. A life-cycle cost framework is defined to capture the benefits and costs of modular alternatives for single or multi-mission (programmatic) applications. A probabilistic risk model to address launch and assembly risks is employed to capture uncertainties in launch, as well as in the assembly approaches and their complexity (number of assembly steps, module connections). An illustration of the tradeoffs between these models for a single mission is described using a 448kW Solar Electric Transport Vehicle (SETV) supporting a human lunar mission. The illustration was limited to the launch and assembly phase from beginning of first element launch to completion of assembly. Results and observations are presented and discussed.

  5. Large-size space debris flyby in low earth orbits

    NASA Astrophysics Data System (ADS)

    Baranov, A. A.; Grishko, D. A.; Razoumny, Y. N.

    2017-09-01

    the analysis of NORAD catalogue of space objects executed with respect to the overall sizes of upper-stages and last stages of carrier rockets allows the classification of 5 groups of large-size space debris (LSSD). These groups are defined according to the proximity of orbital inclinations of the involved objects. The orbits within a group have various values of deviations in the Right Ascension of the Ascending Node (RAAN). It is proposed to use the RAANs deviations' evolution portrait to clarify the orbital planes' relative spatial distribution in a group so that the RAAN deviations should be calculated with respect to the concrete precessing orbital plane of the concrete object. In case of the first three groups (inclinations i = 71°, i = 74°, i = 81°) the straight lines of the RAAN relative deviations almost do not intersect each other. So the simple, successive flyby of group's elements is effective, but the significant value of total Δ V is required to form drift orbits. In case of the fifth group (Sun-synchronous orbits) these straight lines chaotically intersect each other for many times due to the noticeable differences in values of semi-major axes and orbital inclinations. The intersections' existence makes it possible to create such a flyby sequence for LSSD group when the orbit of one LSSD object simultaneously serves as the drift orbit to attain another LSSD object. This flyby scheme requiring less Δ V was called "diagonal." The RAANs deviations' evolution portrait built for the fourth group (to be studied in the paper) contains both types of lines, so the simultaneous combination of diagonal and successive flyby schemes is possible. The value of total Δ V and temporal costs were calculated to cover all the elements of the 4th group. The article is also enriched by the results obtained for the flyby problem solution in case of all the five mentioned LSSD groups. The general recommendations are given concerned with the required reserve of total

  6. Future Large-Aperture Ultraviolet/Optical/Infrared Space Observatory

    NASA Technical Reports Server (NTRS)

    Thronson, Harley; Mandell, Avi; Polidan, Ron; Tumlinson, Jason

    2016-01-01

    Since the beginning of modern astronomical science in the early 1900s, astronomers have yearned to escape the turbulence and absorption of Earth's atmosphere by placing observatories in space. One of the first papers to lay out the advantages of space astronomy was by Lyman Spitzer in 1946, "Astronomical Advantages of an Extra-Terrestrial Observatory," though later in life he minimized the influence of this work. Since that time, and especially gaining momentum in the 1960s after the launch of Sputnik, astronomers, technologists, and engineers continued to advance, organizing scientific conferences, advocating for necessary technologies, and assessing sophisticated designs for increasingly ambitious space observations at ultraviolet, visual, and infrared (UVOIR) wavelengths. These community-wide endeavors, combined with the explosion in technological capability enabled by the Apollo era, led to rapid advancement in space observatory performance that culminated in the spectacularly successful Hubble Space Telescope (HST), launched in 1990 and still returning surpassing scientific results.

  7. 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

  8. 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.

  9. Space exposure of composite materials for large space structures (A0134)

    NASA Technical Reports Server (NTRS)

    Slemp, W. S.

    1984-01-01

    The objective of this experiment is to evaluate the effects of the near-Earth orbital environment on the physical and chemical properties of laminated continuous-filament composites and composites resin films for use in large space structures and advanced spacecraft. The experiment is passive and occupies about one-half of a 6-in.-deep peripheral tray. Specimens of composite materials and polymeric and resin films are arranged above and below the experiment mounting plate to enable both exposure and nonexposure to sunlight. This provides a comparison of the effects of ultraviolet plus vacuum plus thermal cycling and those of vacuum plus thermal cycling on these materials. The experiment tray is thermally isolated from the Long Duration Exposure Facility structure to allow the material specimens to experience a wide range of thermal cycles. Tensile and compression specimens will be used to evaluate the laminated composite materials. A number of the specimens are precut and ready for testing after space exposure, whereas other specimens will be prepared from larger samples.

  10. Response of large cavity ion chambers to space protons

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Khandelwal, G. S.

    1981-01-01

    The assumption that spherical-shell ion chamber rssponse is equal to the dose in the center of the cavity is found to be a poor approximation for ion chambers used for area monitoring in the space program. The dose response is calculated using the appropriate areal density distribution function. Effects of nuclear reaction are evaluated using proton buildup factors. Errors of up to 100% are found for some components of the space radiation environments.

  11. Large area flexible solar array design for Space Shuttle application

    NASA Technical Reports Server (NTRS)

    Souza, C. J.

    1980-01-01

    A large area flexible solar array has been designed for Shuttle power augmentation. The solar array utilizes large area, low cost, weldable solar cells. The paper addresses how the unique requirements of this system are implemented into the design. Economic and reliability issues relating to the optimization of a large area, foldable solar array concomitant to the Shuttle/Orbiter system are reviewed.

  12. 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.

  13. 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.

  14. Adaptive and learning control of large space structures

    NASA Technical Reports Server (NTRS)

    Montgomery, R. C.; Thau, F. J.

    1980-01-01

    The paper describes the adaptive learning system for space operations which assumes that structural testing can be conducted during deployment and assembly. Simulation results using the solar electric propulsion array and a novel remote sensor are presented; they involve faster scan television coverage of the motions of the array from four cameras on the corners of the Space Shuttle payload bay. The description of the simulation, the filtering algorithm for processing the TV data, the parameter extraction algorithm, and the simulation results are presented.

  15. 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.

  16. Adaptive and learning control of large space structures

    NASA Technical Reports Server (NTRS)

    Montgomery, R. C.; Thau, F. J.

    1980-01-01

    The paper describes the adaptive learning system for space operations which assumes that structural testing can be conducted during deployment and assembly. Simulation results using the solar electric propulsion array and a novel remote sensor are presented; they involve faster scan television coverage of the motions of the array from four cameras on the corners of the Space Shuttle payload bay. The description of the simulation, the filtering algorithm for processing the TV data, the parameter extraction algorithm, and the simulation results are presented.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. A logistics model for large space power systems

    NASA Astrophysics Data System (ADS)

    Koelle, H. H.

    Space Power Systems (SPS) have to overcome two hurdles: (1) to find an attractive design, manufacturing and assembly concept and (2) to have available a space transportation system that can provide economical logistic support during the construction and operational phases. An initial system feasibility study, some five years ago, was based on a reference system that used terrestrial resources only and was based partially on electric propulsion systems. The conclusion was: it is feasible but not yet economically competitive with other options. This study is based on terrestrial and extraterrestrial resources and on chemical (LH 2/LOX) propulsion systems. These engines are available from the Space Shuttle production line and require small changes only. Other so-called advanced propulsion systems investigated did not prove economically superior if lunar LOX is available! We assume that a Shuttle derived Heavy Lift Launch Vehicle (HLLV) will become available around the turn of the century and that this will be used to establish a research base on the lunar surface. This lunar base has the potential to grow into a lunar factory producing LOX and construction materials for supporting among other projects also the construction of space power systems in geostationary orbit. A model was developed to simulate the logistics support of such an operation for a 50-year life cycle. After 50 years 111 SPS units with 5 GW each and an availability of 90% will produce 100 × 5 = 500 GW. The model comprises 60 equations and requires 29 assumptions of the parameter involved. 60-state variables calculated with the 60 equations mentioned above are given on an annual basis and as averages for the 50-year life cycle. Recycling of defective parts in geostationary orbit is one of the features of the model. The state-of-the-art with respect to SPS technology is introduced as a variable Mg mass/MW electric power delivered. If the space manufacturing facility, a maintenance and repair facility

  2. Convected transient analysis for large space structures maneuver and deployment

    NASA Technical Reports Server (NTRS)

    Housner, J.

    1984-01-01

    Convected-transient analysis techniques in the finite-element method are used to investigate the deployment and maneuver of large spacecraft structures with multiple-member flexible trusses and frames. Numerical results are presented for several sample problems.

  3. 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.

  4. Optical Detection of Space Debris Using a Large Achromatic Coronagraph

    DTIC Science & Technology

    1988-01-01

    34Exploter 46 Meteoroid Bumper Experiment: Earth orbital debris interpretation", in "Properties and Interactions of Interplanetary Dust", Astrophy- sics and...communication, 9th Sacramento Peak Workshop on Coronal Structure, 17-21th August. Su, S. Y.: 1986, " Orbital Debris Environement resulting from Future Activities...in Space", Adv. Sp. Res., 6, 7, 109. Taff, L. G., Jonuskis, D. M.: 1986, "Results and Analysis of a bi-telescopic Sur- vey of low Altitude Orbital

  5. Preparation of large-particle-size monodisperse latexes in space

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    Results are reported of latex sphere polymerization experiments performed on two flights of the Columbia and three flights of the Challenger. The trials were carried out because polymerization of the spheres in space avoids coagulation, nucleation of a new crop of particles, and excessive stirring requirements, and allows growth of spheres larger than 4 microns diam. The Monodisperse Latex Reactor (MLR) held four stirred 100 cc sealed stainless steel cylindrical containers. The mixtures were monitored for the conversion times, volume decreases as spheres formed and the mixture temperature. The spheres were grown from 0.19 micron seeds. Details of the flight preparation efforts are outlined. In flights which did not experience mechanical malfunctions spheres 3-30 microns diam were grown that had noticeably lower size variations than did the ground-based control particles. The 10 micron diam spheres grown on STS-6 were accepted as standard reference material by the NBS and became the first products made in space to be commercially sold on earth; the 30 micron spheres also became NBS standards. The experiments confirmed all projected benefits of producing the spheres in space, as well as provided the opportunity to grow more larger offsize spheres by finishing the growths on earth.

  6. Preparation of large-particle-size monodisperse latexes in space

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    Results are reported of latex sphere polymerization experiments performed on two flights of the Columbia and three flights of the Challenger. The trials were carried out because polymerization of the spheres in space avoids coagulation, nucleation of a new crop of particles, and excessive stirring requirements, and allows growth of spheres larger than 4 microns diam. The Monodisperse Latex Reactor (MLR) held four stirred 100 cc sealed stainless steel cylindrical containers. The mixtures were monitored for the conversion times, volume decreases as spheres formed and the mixture temperature. The spheres were grown from 0.19 micron seeds. Details of the flight preparation efforts are outlined. In flights which did not experience mechanical malfunctions spheres 3-30 microns diam were grown that had noticeably lower size variations than did the ground-based control particles. The 10 micron diam spheres grown on STS-6 were accepted as standard reference material by the NBS and became the first products made in space to be commercially sold on earth; the 30 micron spheres also became NBS standards. The experiments confirmed all projected benefits of producing the spheres in space, as well as provided the opportunity to grow more larger offsize spheres by finishing the growths on earth.

  7. 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.

  8. A Model for Predicting Thermomechanical Response of Large Space Structures.

    DTIC Science & Technology

    1985-06-01

    PERSONAL AUTHOR(S) D.H. Allen and W.E. Haisler 13. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (P.. M.. Day, 1. PAGE COUNT Annual FROMMay 󈨘 TO...TITLE ’inciude Security Claaaficatlon4 Developrrmnt of a Theoretical Frarrevork for nstitutive uations f r Metal t.,Iatrix 12. PERSONAL AUTHOR(S...Response of La ge Space St uctures 12. PERSONAL AUTHOR(S) S. Kalyanasundaram, J.D. Lutz, W.E. Haisler, D.H. Allen 13. TYPE OF REPORT 13b. TIME COVERED U4

  9. 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

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

    NASA Technical Reports Server (NTRS)

    Effinger, Mike; Stahl, H. Philip

    2015-01-01

    The Advanced Mirror Technology Development (AMTD) project is in phase 2 of a multiyear effort, initiated in FY 2012. This effort is to mature, by at least a half Technology Readiness Level step, the critical technologies required to enable 4-meter or larger ultraviolet, optical, and infrared (UVOIR) space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD continues to achieve all of its goals and has accomplished all of its milestones to date. This has been achieved by assembling an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes; by deriving engineering specifications for advanced normal-incidence mirror systems needed to make the required science measurements; and by defining and prioritizing the most important technical problems to be solved. Our results have been presented to the CoPAG and Mirror Tech Days 2013, and proceedings papers of the 2013 and 2014 SPIE Optics & Photonics Symposia have been published.

  11. Overview of Mirror Technology Development for Large Lightweight Space-Based Optical Systems

    NASA Technical Reports Server (NTRS)

    Smith, W. Scott; Stahl, H. P.; Rose, M. Frank (Technical Monitor)

    2000-01-01

    The Space Optics Manufacturing Technology Center of Marshall Space Flight Center is involved in the development of lightweight optics for spacebased'systems. The NGST and other future NASA programs require large aperture space-based instruments. This paper reviews the technologies under development for NGST including discussions of the environmental testing of candidate segment for the NGST primary mirror.

  12. 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.

  13. 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.

  14. Dynamic dissipative compensator design for large space structures

    NASA Technical Reports Server (NTRS)

    Joshi, S. M.; Maghami, P. G.; Kelkar, A. G.

    1991-01-01

    Control system design is considered for attitude control and vibration suppression of flexible space structures. The problem addressed is that of controlling both the zero-frequency rigid-body modes and the elastic modes. Model-based compensators, which employ observers tuned to the plant parameters, are first investigated. Such compensators are shown to generally exhibit high sensitivity to the knowledge of the parameters, especially the elastic mode frequencies. To overcome this problem a class of dynamic dissipative compensators is next proposed, which robustly stabilize the plant in the presence of unmodeled dynamics and parametric uncertainties. An analytical proof of robust stability is given, and a method of implementing the controller as a strictly proper compensator is given. Methods of designing such controllers to obtain optimal performance and robust stability are presented. Numerical and experimental results of application of the methods are presented, which indicate that dynamic dissipative controllers can simultaneously provide excellent performance and robustness.

  15. 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.

  16. 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.

  17. Osmotic pumped heat pipes for large space platforms

    NASA Astrophysics Data System (ADS)

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

    1982-06-01

    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.

  18. 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.

  19. Large zeolites - Why and how to grow in space

    NASA Technical Reports Server (NTRS)

    Sacco, Albert, Jr.

    1991-01-01

    The growth of zeolite crystals which are considered to be the most valuable catalytic and adsorbent materials of the chemical processing industry are discussed. It is proposed to use triethanolamine as a nucleation control agent to control the time release of Al in a zeolite A solution and to increase the average and maximum crystal size by 25-50 times. Large zeolites could be utilized to make membranes for reactors/separators which will substantially increase their efficiency.

  20. 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.

  1. 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.

  2. 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.

  3. A Model for Predicting Thermomechanical Response of Large Space Structures.

    DTIC Science & Technology

    1984-06-01

    micropolar analogy to model large grid frameworks under initial axial forces. This continuous approximation is formulated even for the case of variable member...solutions show that results obtained are accurate especially in the range of long wavelengths. Noor and Nemeth [97] have developed micropolar models for...34 % Computer Methods in Applied Mechanics and Engineering, Vol. 25, pp. 179- 193, 1981. 95. Bazant, Z. P., Christensen, M., "Analogy Between Micropolar

  4. 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.

  5. 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.

  6. Utilization of Space Station by the Large Deployment Reflector

    NASA Technical Reports Server (NTRS)

    Bandermann, L. W.; Alff, W. H.

    1985-01-01

    The Large Deployable Reflector (LDR), a NASA concept of a very large, orbiting, far infrared submillimeter telescope is described. To be launched in the 1990s, LDR has a projected life of 10 years and is to be serviced every 2 to 3 years. A System Concept and Technology Definition Study of LDR for NASA Ames is currently being conducted. Study results indicate that launch of a 20 m LDR, operating in a 700 to 800 km orbit, requires two shuttle loads. The components of LDR are assembled in a lower parking orbit, and the system is checked out and then transferred to the operational orbit. Furthermore, for servicing, LDR may have to be retrieved to the same lower orbit (and later returned to operational altitude) by an orbit transfer vehicle. These requirements bring up the question of a suitable assembly, checkout, and servicing platform. The deployment process is time consuming and may require special equipment not necessarily available from the orbiter itself. The SS is an attractive choice for that platform.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Retention of memory for large-scale spaces.

    PubMed

    Ishikawa, Toru

    2013-01-01

    This study empirically examined the retention of large-scale spatial memory, taking different types of spatial knowledge and levels of sense of direction into consideration. A total of 38 participants learned a route from a video and conducted spatial tasks immediately after learning the route and after 2 weeks or 3 months had passed. Results showed that spatial memory decayed over time, at a faster rate for the first 2-week period than for the subsequent period of up to 3 months, although it was not completely forgotten even after 3 months. The rate of forgetting differed depending on the type of knowledge, with landmark and route knowledge deteriorating at a much faster rate than survey knowledge. Sense of direction affected both the acquisition and the retention of survey knowledge. Survey knowledge by people with a good sense of direction was more accurate and decayed much less than that by people with a poor sense of direction.

  12. 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.

  13. 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.

  14. 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.

  15. Free-decay time-domain modal identification for large space structures

    NASA Technical Reports Server (NTRS)

    Kim, Hyoung M.; Vanhorn, David A.; Doiron, Harold H.

    1992-01-01

    Concept definition studies for the Modal Identification Experiment (MIE), a proposed space flight experiment for the Space Station Freedom (SSF), have demonstrated advantages and compatibility of free-decay time-domain modal identification techniques with the on-orbit operational constraints of large space structures. Since practical experience with modal identification using actual free-decay responses of large space structures is very limited, several numerical and test data reduction studies were conducted. Major issues and solutions were addressed, including closely-spaced modes, wide frequency range of interest, data acquisition errors, sampling delay, excitation limitations, nonlinearities, and unknown disturbances during free-decay data acquisition. The data processing strategies developed in these studies were applied to numerical simulations of the MIE, test data from a deployable truss, and launch vehicle flight data. Results of these studies indicate free-decay time-domain modal identification methods can provide accurate modal parameters necessary to characterize the structural dynamics of large space structures.

  16. Target prediction utilising negative bioactivity data covering large chemical space.

    PubMed

    Mervin, Lewis H; Afzal, Avid M; Drakakis, Georgios; Lewis, Richard; Engkvist, Ola; Bender, Andreas

    2015-01-01

    In silico analyses are increasingly being used to support mode-of-action investigations; however many such approaches do not utilise the large amounts of inactive data held in chemogenomic repositories. The objective of this work is concerned with the integration of such bioactivity data in the target prediction of orphan compounds to produce the probability of activity and inactivity for a range of targets. To this end, a novel human bioactivity data set was constructed through the assimilation of over 195 million bioactivity data points deposited in the ChEMBL and PubChem repositories, and the subsequent application of a sphere-exclusion selection algorithm to oversample presumed inactive compounds. A Bernoulli Naïve Bayes algorithm was trained using the data and evaluated using fivefold cross-validation, achieving a mean recall and precision of 67.7 and 63.8 % for active compounds and 99.6 and 99.7 % for inactive compounds, respectively. We show the performances of the models are considerably influenced by the underlying intraclass training similarity, the size of a given class of compounds, and the degree of additional oversampling. The method was also validated using compounds extracted from WOMBAT producing average precision-recall AUC and BEDROC scores of 0.56 and 0.85, respectively. Inactive data points used for this test are based on presumed inactivity, producing an approximated indication of the true extrapolative ability of the models. A distance-based applicability domain analysis was also conducted; indicating an average Tanimoto Coefficient distance of 0.3 or greater between a test and training set can be used to give a global measure of confidence in model predictions. A final comparison to a method trained solely on active data from ChEMBL performed with precision-recall AUC and BEDROC scores of 0.45 and 0.76. The inclusion of inactive data for model training produces models with superior AUC and improved early recognition capabilities, although

  17. 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.

  18. Development of a large area space solar cell assembly

    NASA Astrophysics Data System (ADS)

    Spitzer, M. B.

    1982-05-01

    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.

  19. Stability Analysis for a Large-scale Space Power Network, International Space Station and Japanese Experiment Module

    NASA Astrophysics Data System (ADS)

    Komatsu, Masaaki; Arai, Satoaki

    The International Space Station (ISS), which is scheduled to start the operation fully in early 2000’s, is being developed and assembled on orbit since 1998 with international cooperation of the USA, Russia, Europe, Canada, and Japan. Japan participates in this ISS program and will provide the Japanese Experiment Module (JEM, named “Kibo") which will be attached to the ISS core. Japan Aerospace Exploration Agency (JAXA), which is responsible for the JEM system development and integration, has been developed JEM Electric Power System (JEM EPS) as part of the Space Station Electric Power System (EPS). The International Space Station Electric Power System is the world’s largest orbiting direct-current (DC) power system. The ISS electric power is generated by solar arrays, and distributed to the each module in 120 Vdc bus voltage rating. When designing a large-scale Space Power System using direct current (DC), special attention must be placed on the electrical stability and control of the system and individual load on the system. For a large-scale Space Power System, it is not feasible to design the entire system as a whole. Instead, the system can be defined in term of numerous small blocks, and each block then designed individually. The individual blocks are then integrated to form a complete system. The International Space Station (ISS) is one of good example for these issue and concerns as a large-scale Space Power System. This paper describes the approach of the stability analysis for a large-scale space power network.

  20. 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.

  1. Large space system - Charged particle environment interaction technology. [effects on high voltage solar array performance

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.; Roche, J. C.; Grier, N. T.

    1979-01-01

    Large high-voltage space power systems proposed for future applications in both low earth orbit and geosynchronous altitudes must operate in the space charged-particle environment with possible interactions between this environment and the high-voltage surfaces. The paper reviews the ground experimental work to provide indicators for the interactions that could exist in the space power system. A preliminary analytical model of a large space power system is constructed using the existing NASA Charging Analyzer Program, and its performance in geosynchronous orbit is evaluated. The analytical results are used to illustrate the regions where detrimental interactions could exist and to establish areas where future technology is required.

  2. 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.

  3. Large bearing operation without retainer. [high speed ball bearings for space application

    NASA Technical Reports Server (NTRS)

    Kingsbury, E.

    1978-01-01

    The design and testing of large high-speed ball bearings for space application is described. A well-defined lubrication system to provide oil to both race contacts in zero g allows stable operation without ball retainer.

  4. Large bearing operation without retainer. [high speed ball bearings for space application

    NASA Technical Reports Server (NTRS)

    Kingsbury, E.

    1978-01-01

    The design and testing of large high-speed ball bearings for space application is described. A well-defined lubrication system to provide oil to both race contacts in zero g allows stable operation without ball retainer.

  5. Research on elastic large space structures as "plants' for active control

    NASA Technical Reports Server (NTRS)

    Ashley, H.; Vonflotow, A.

    1983-01-01

    Research on active control of large space structures is discussed. Intrinsic damping in monolithic metallic structures is discussed. Thermal relaxation and grain boundary relaxation are discussed, as are properties of thermal damping.

  6. The large silicon tracker for the AMS experiment on the International Space Station Alpha (ISSA)

    NASA Astrophysics Data System (ADS)

    Pauluzzi, M.

    1996-02-01

    The design of the high precision microstrip silicon tracker for the Alpha Magnetic Spectrometer experiment (AMS) is presented. We emphasize features of the silicon tracker which make it suitable for a space born experiment and for equipping large active areas.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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; hide

    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.

  17. 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.

  18. Design of Large Lightweight Space Telescope Optical Systems for the Next Generation Space Telescope

    NASA Technical Reports Server (NTRS)

    Jacobson, Dave; Craig, Larry; Schunk, Greg; Shapiro, Alan; Cloyd, Dick; Ricks, Ed; Vacarro, Mark; Redding, Dave; Hadaway, James; Bely, Pierre

    1998-01-01

    The Next Generation Space Telescope (NGST) is currently in a Pre Phase A study effort to prove feasibility of design and to show that the design can be implemented within cost constraint guidelines and meet the requirements of the science community. In an effort to achieve the science communities goals as outlined in "HST and Beyond" the NGST team has developed a government "yardstick" design of an eight meter diameter segmented telescope which would be launched in an Atlas IIAS launch vehicle to a L2 (Lagrange Point) orbit. This paper will discuss the design of the Optical Telescope Assembly (OTA) and the various issues and complications of designing lightweight optics to be placed in the environment that the NGST will encounter both during launch and during its operational mission at L2. The OTA must be lightweight but structurally must withstand the launch environment and transfer to its final L2 orbit. The OTA must be stable at L2 to provide high quality science at the cryogenic temperatures it will experience. The OTA segmented petal concept is to develop lightweight optics which can either be manipulated to achieve and maintain a desired figure or be rigid enough so that change in shape is only necessary for phasing and alignment. The secondary mirror structural mast must also be rigid with frequency responses which are not coupled to spacecraft modes in order to maintain and decenter and despace requirements.

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

    NASA Astrophysics Data System (ADS)

    Chu, Zhongyi; Di, Jingnan; Cui, Jing

    2017-10-01

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

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    Slepian, Zachary; Eisenstein, Daniel J.

    2017-08-01

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

  2. 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.

  3. SparseLeap: Efficient Empty Space Skipping for Large-Scale Volume Rendering.

    PubMed

    Hadwiger, Markus; Al-Awami, Ali K; Beyer, Johanna; Agus, Marco; Pfister, Hanspeter

    2017-08-29

    Recent advances in data acquisition produce volume data of very high resolution and large size, such as terabyte-sized microscopy volumes. These data often contain many fine and intricate structures, which pose huge challenges for volume rendering, and make it particularly important to efficiently skip empty space. This paper addresses two major challenges: (1) The complexity of large volumes containing fine structures often leads to highly fragmented space subdivisions that make empty regions hard to skip efficiently. (2) The classification of space into empty and non-empty regions changes frequently, because the user or the evaluation of an interactive query activate a different set of objects, which makes it unfeasible to pre-compute a well-adapted space subdivision. We describe the novel SparseLeap method for efficient empty space skipping in very large volumes, even around fine structures. The main performance characteristic of SparseLeap is that it moves the major cost of empty space skipping out of the ray-casting stage. We achieve this via a hybrid strategy that balances the computational load between determining empty ray segments in a rasterization (object-order) stage, and sampling non-empty volume data in the ray-casting (image-order) stage. Before ray-casting, we exploit the fast hardware rasterization of GPUs to create a ray segment list for each pixel, which identifies non-empty regions along the ray. The ray-casting stage then leaps over empty space without hierarchy traversal. Ray segment lists are created by rasterizing a set of fine-grained, view-independent bounding boxes. Frame coherence is exploited by re-using the same bounding boxes unless the set of active objects changes. We show that SparseLeap scales better to large, sparse data than standard octree empty space skipping.

  4. Addressing the problem of interruptability in the construction of large space structures

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Morgenthaler, George W.

    1989-01-01

    Large scale space missions of the near future will depend upon successful multi-launch coordination and construction in the space environment. One of the main challenges is how to accomplish a valid global analysis of a construction project with the intent of improving safety, reducing overall mission cost, and total construction time. These three items are dependent on the interruptability of the project, which is the ability of the project to recover from unplanned interruptions; such as failure of the launch vehicle; sudden, on-orbit, crew illness; or damage from a space debris impact on the partially completed space structure. A new method for addressing and analyzing this type of problem is being developed. The method is called Program Interruptability and Risk Evaluation Technique, or PIRET. PIRET has been developed in order to model and analyze potential interruptability concerns of the construction of the U.S. Space Station Freedom (SSF), although PIRET is applicable to any complex, multi-launch structural assembly. This paper is a progress report on the continuing research of the NASA Center for Space Construction at the University of Colorado, Boulder into this area of space construction interruptability. The paper will define the problem of interruptability, will diagram the PIRET approach to space construction, will share results from a preliminary PIRET analysis of SSF, and will show that PIRET is a useful tool for modelling space construction interruptability.

  5. Addressing the problem of interruptability in the construction of large space structures

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Morgenthaler, George W.

    1989-01-01

    Large scale space missions of the near future will depend upon successful multi-launch coordination and construction in the space environment. One of the main challenges is how to accomplish a valid global analysis of a construction project with the intent of improving safety, reducing overall mission cost, and total construction time. These three items are dependent on the interruptability of the project, which is the ability of the project to recover from unplanned interruptions; such as failure of the launch vehicle; sudden, on-orbit, crew illness; or damage from a space debris impact on the partially completed space structure. A new method for addressing and analyzing this type of problem is being developed. The method is called Program Interruptability and Risk Evaluation Technique, or PIRET. PIRET has been developed in order to model and analyze potential interruptability concerns of the construction of the U.S. Space Station Freedom (SSF), although PIRET is applicable to any complex, multi-launch structural assembly. This paper is a progress report on the continuing research of the NASA Center for Space Construction at the University of Colorado, Boulder into this area of space construction interruptability. The paper will define the problem of interruptability, will diagram the PIRET approach to space construction, will share results from a preliminary PIRET analysis of SSF, and will show that PIRET is a useful tool for modelling space construction interruptability.

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Rahmatsamii, Y.

    1988-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. The reduced order model problem in distributed parameter systems adaptive identification and control. [large space structures

    NASA Technical Reports Server (NTRS)

    Johnson, C. R., Jr.; Lawrence, D.

    1981-01-01

    The basic assumption that a large space structure can be decoupled preceding the application of reduced order active control was considered and alternative solutions to the control of such structures (in contrast to the strict modal control) were investigated. The transfer function matrix from the actuators to the sensors was deemed to be a reasonable candidate. More refined models from multivariable systems theory were studied and recent results in the multivariable control field were compared with respect to theoretical deficiencies and likely problems in application to large space structures.

  13. 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.

  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. 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.

  16. 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.

  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 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.

  18. 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.

  19. 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

  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. 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.

  4. Decentralized Control of a Large Space Structure as Applied to the CSDL 2 Model.

    DTIC Science & Technology

    1982-12-01

    42 V. Computer Model ........ ..................... 49 VI. Investigation ......... ..................... 54 Outline...therefore, the ontroller vur ae coud nt be verified. DECENTRALIZED CONTROL OF A LARGE SPACE STRUCTURE AS APPLIED TO THE CSDL 2 MODEL I. Introduction...performaJ by on-line computers , larger controller dimensions result In slower control response. To kehp the controllers dimensionally realistic, modeling

  5. 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.

  6. Use of domestic fuels for large-scale space heating and for district heating

    SciTech Connect

    Seppaelae, R.; Asplund, D.

    1980-01-01

    The aim of the study was to survey the heating systems for large-scale space heating and district heating with domestic fuels or under development in Finland, and to study alternative technico-economic applications in the size class of 0.5 - 5 MW.

  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. Sequential Multisine Excitation Signals for System Identification of Large Space Structures

    DTIC Science & Technology

    2005-09-06

    Linear system identification of complex nonlinear systems, such as large space structures, can be difficult because such systems are often lightly...used to collect frequency response data for linear system identification are poorly suited to systems that exhibit nonlinear responses. Specifically

  9. 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.

  10. Coordinated stabilization for space robot after capturing a noncooperative target with large inertia

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Liang, Bin; Wang, Ziwei; Mi, Yilin; Zhang, Yiman; Chen, Zhang

    2017-05-01

    A noncooperative target with large inertia grasped by space robot may contain a large unkonwn initial angular momentum, which will cause the compound system unstable. Unloading the unkonwn angular momentum of the compound system is a necessary and diffcult task. In the paper, a coordinated stabilization scenario is introduced to reduce the angular momentum, which has two stages, Momentum Reduction and Momentum Redistribution. For the Momentum Reduction, a modified adaptive sliding mode control algorithm is proposed and used to reduce the unknown angular momentum of target, which uses a new signum function and time-delay estimation to assure fast convergence and achieve good performance with small chattering effect. Finally, a plane dual-arm space robot is simulated, the numerical simulations show that the proposed control algorithm is able to stabilize a noncooperative target with large inertia successfully, while the attitude disturbance of base is small. The control algorithm also has a good robust performance.

  11. Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

    NASA Astrophysics Data System (ADS)

    Bolcar, Matthew R.; Balasubramanian, Kunjithapatham; Crooke, Julie; Feinberg, Lee; Quijada, Manuel; Rauscher, Bernard J.; Redding, David; Rioux, Norman; Shaklan, Stuart; Stahl, H. Philip; Stahle, Carl M.; Thronson, Harley

    2016-10-01

    The Advanced Technology Large Aperture Space Telescope (ATLAST) team identified five key technology areas to enable candidate architectures for a future large-aperture ultraviolet/optical/infrared (LUVOIR) space observatory envisioned by the NASA Astrophysics 30-year roadmap, "Enduring Quests, Daring Visions." The science goals of ATLAST address a broad range of astrophysical questions from early galaxy and star formation to the processes that contributed to the formation of life on Earth, combining general astrophysics with direct-imaging and spectroscopy of habitable exoplanets. The key technology areas are internal coronagraphs, starshades (or external occulters), ultra-stable large-aperture telescope systems, detectors, and mirror coatings. For each technology area, we define best estimates of required capabilities, current state-of-the-art performance, and current technology readiness level (TRL), thus identifying the current technology gap. We also report on current, planned, or recommended efforts to develop each technology to TRL 5.

  12. Fundamental studies of heat load and thermal-structure analysis of large space structures

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.

    1983-01-01

    Investigation of the basic requirements for modeling slender member shadowing effects on thermally induced deformation continues. The theoretical formulation is complete and computer programming is underway. The basic requirements for thermal finite elements to model heat transfer in orbiting structures were also studied. The need for planar isothermal elements to model large space structures' antenna meshes was established. Finite Element approaches for modeling space structure cable and membrane components with thermal effects is underway. Three levels of structural modeling and analysis were identified: (1) a linear-elastic small deflection analysis that does not permit cable slackening; (2) a linear-elastic analysis that includes stress stiffening (the ANSYS program), but not large deflections; and (3) full nonlinear large deflection analysis with stress stiffening. Methods of determining cable initial tensions are currently being evaluated.

  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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

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

    PubMed

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

    2013-01-01

    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.

  20. Large eddy simulation in a turbulent jet exhausting into a submerged space or a cocurrent flow

    NASA Astrophysics Data System (ADS)

    Volkov, K. N.

    2011-01-01

    Results of large eddy simulations in a subsonic isothermal turbulent jet exhausting from a circular nozzle into a submerged space or a cocurrent flow are presented. The flow is described by space-averaged Navier-Stokes equations and by the RNG model of subgrid scale viscosity. Results computed for different values of the cocurrency parameter are compared with available results of numerical simulations and experimental data. The results obtained are found to agree well with measured data and to confirm the basic laws of variation of gas-dynamic and fluctuating parameters of submerged and cocurrent jets.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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; hide

    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.

  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. 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.

  13. Large space-based systems for dealing with global environment change

    NASA Technical Reports Server (NTRS)

    Jenkins, Lyle M.

    1992-01-01

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

  14. Large space-based systems for dealing with global environment change

    NASA Technical Reports Server (NTRS)

    Jenkins, Lyle M.

    1992-01-01

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

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Passivity control with practically finite-time convergence for large space structures

    NASA Astrophysics Data System (ADS)

    Hu, Quan; Li, Jinyue; Zhang, Jingrui

    2017-02-01

    A nonlinear output feedback control law based on passivity is proposed to reduce the vibration of large space structures. The considered system is assumed to be equipped with collocated actuators and sensors. The concept of practically finite-time stability is first developed to describe the finite-time convergence of a passive system. Then, an output feedback is introduced to drive the trajectories of a passive system into a small set around the origin in finite time. Finally, the proposed control strategy is applied to the vibration suppression of large space structures with distributed thrusters and velocity sensors or torque outputting devices and angular rate sensors. Numerical simulations are conducted to validate the effectiveness of the proposed controller.

  3. 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.

  4. Fabrication of large-aperture, high efficiency, Fresnel diffractive membrane optic for space telescope

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Li, Mengjuan; Yin, Ganghua; Jiao, Jianchao; Liu, Zhengkun; Xu, Xiangdong; Fu, Shaojun

    2016-10-01

    Diffractive optical system can be a favorable choice for large-aperture space telescope to reduce the mass and size of image system. To meet the demand of large-aperture, high efficiency, lightweight diffractive optic for high resolution remote sensing, a 200 mm diameter, 20 μmthick, 4-level diffractive membrane fabricated is shown to have over 62% diffraction efficiency into the +1 order, with 0.051 efficiency RMS. Over 66% diffraction efficiency is achieved for a 100 mm aperture membrane, with 0.023 efficiency RMS. The membrane thickness uniformity control is discussed and 8 nm wave front error RMS is achieved in 100 mm diameter.

  5. 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.

  6. 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.

  7. 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.

  8. EVA Assembly of Large Space Structure Neutral Buoyancy, Zero-Gravity Simulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    EVA Assembly of Large Space Structure Neutral Buoyancy, Zero-Gravity Simulation: NASA-LaRC Nestable Columns and Joints. The film depicts an extravehicular activity (EVA) that involved the assembly of six 'space-weight' columns 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, achieved by neutral buoyancy in water. The cell was assembled on an 'outrigger' assembly aid off the side of a mockup of the Shuttle Orbiter cargo bay. Both manual and simulated remote manipulator system (RMS) modes were evaluated. The simulated RMS was used only to transfer stowed hardware from the cargo bay to the work sites. 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 structur is well within man's capabilities. [Entire movie available on DVD from CASI as Doc ID 20070031008. Contact help@sti.nasa.gov

  9. Study on supporting force sensing and control during large aperture space mirror test

    NASA Astrophysics Data System (ADS)

    Zhang, Long; Hu, Wenqi; Zheng, Liehua; Hao, Peiming

    2016-10-01

    During the machining of large aperture lightweight space mirror, the mirror figure consistency between ground test and space mission is a problem. In order to effectively control the supporting deformation effect on test results in gravity environment, in view of a 1.2-m space mirror with back blind holes, a supporting method for optical axis horizontal test is proposed, with this method, mirror under test is positioned by three center hole surfaces and supported by six external hole surfaces. The effect of deformation caused by different supporting force value, area and position is analyzed by finite element method, the simulation results show that this supporting method can control the mirror supporting deformation within PV0.035λ rms0.005λ. The actual supporting system uses soft expansion mandrel to control the mirror position and pneumatic lever to realize the floating support. In order to ensure that the support force can evenly distribute on the contact surface, a pressure mapping system is adopted to measure the interface pressure between the mirror blind holes and the soft supporting pads for the first time. This method can meet the test requirements of rms=1/40λ mirror and provides a technical support for high precision test of large aperture space mirror with back blind holes.

  10. 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.

  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. 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.

  13. JPL self pulsed laser surface measurement system development. [large space deployed antenna structures

    NASA Technical Reports Server (NTRS)

    Berdahl, M.

    1980-01-01

    The use of a self pulsed laser system for accurately describing the surface shape of large space deployed antenna structures was evaluated. Tests with a breadboard system verified functional operation with short time resolution on the order of .2 mm, nonambiguous ranging, and a maximum range capability on the order of 150 m. The projected capability of the system is resolution of less than .1 mm over a reasonable time period and a range extension to over 300 m.

  14. 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.

  15. Inflight optical measurement of antenna surfaces. [triangulation to measure deformations of large space structures

    NASA Technical Reports Server (NTRS)

    Neiswander, R. S.

    1978-01-01

    A technology base was developed for a wide variety of applications oriented sensors to meet requirements for the fabrication, assembly, test, surface figure monitoring, and ultimately surface figure active control of large space antennas. An optical sensor technique is described which establishes an ideal centerline at each beam during fabrication or later during assembly. Deviations from the centerline, either in lateral deformation or in twist, are measured to produce limit warnings or to evoke active control at the building machine.

  16. 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.

  17. Out-of-Furnace Brazing Technology for Assembly of Large Carbon-Carbon Space Structures.

    DTIC Science & Technology

    1994-04-01

    composites required use of high temperature vacuum furnaces which, in addition to needing costly mechanical and diffusion vacuum pumps, also require...structures such as Space Based Radar ( SBR ), Survivable Power Subsystem (SUPER), and Zenith STAR may involve C/C structures in excess of 350 ft. Figure 3...depicts the size and complexity of some of these structures. Consequently, mechanical fastening becomes the joining method of choice for large C/C

  18. 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.

  19. Space switching enabled tunable wavelength converter and its application in large scale optical interconnect architecture

    NASA Astrophysics Data System (ADS)

    Xu, Zhaowen; Zhou, Luying; Cheng, Xiaofei

    2016-01-01

    We propose a large scale Clos structure based optical interconnect by employing cyclic arrayed waveguide grating routers (AWGRs) and novel space switching enabled tunable wavelength converters (SS-TWCs). The 1:2 or 1:4 SS-TWCs expand the scale of the optical interconnect up to 8 times of standard Clos structure while using the same AWGR modules. Experimental results are given to demonstrate the feasibility of the proposed optical interconnect.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. An observer for a deployable antenna. [for large space structure flight experiment

    NASA Technical Reports Server (NTRS)

    Waites, H. B.

    1981-01-01

    An observer is derived for use on an Orbiter-Deployable Antenna configuration. The unique feature of this observer design for this flight experiment is that all the plant inputs are not required to be directly accessible for the observer to ferret out the system states. The observer uses state and rate of the state information to reconstruct the plant states. Results are presented which show how effectively this observer design works for this large space structure flight experiment.

  5. Inflight optical measurement of antenna surfaces. [triangulation to measure deformations of large space structures

    NASA Technical Reports Server (NTRS)

    Neiswander, R. S.

    1978-01-01

    A technology base was developed for a wide variety of applications oriented sensors to meet requirements for the fabrication, assembly, test, surface figure monitoring, and ultimately surface figure active control of large space antennas. An optical sensor technique is described which establishes an ideal centerline at each beam during fabrication or later during assembly. Deviations from the centerline, either in lateral deformation or in twist, are measured to produce limit warnings or to evoke active control at the building machine.

  6. An observer for a deployable antenna. [for large space structure flight experiment

    NASA Technical Reports Server (NTRS)

    Waites, H. B.

    1981-01-01

    An observer is derived for use on an Orbiter-Deployable Antenna configuration. The unique feature of this observer design for this flight experiment is that all the plant inputs are not required to be directly accessible for the observer to ferret out the system states. The observer uses state and rate of the state information to reconstruct the plant states. Results are presented which show how effectively this observer design works for this large space structure flight experiment.

  7. 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.

  8. 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.

  9. 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.

  10. Propellantless precision formation flying with photonic laser thrusters for large space telescopes

    NASA Astrophysics Data System (ADS)

    Bae, Young K.

    2009-08-01

    One economically and technologically feasible bedrock structure for constructing large (diameter > 10 m) space telescopes is a segmented or sparse aperture system with subcomponents in precision formation flight. For UV/Visible/IR systems, initial targeting and targeting new objects to establish initial fringes requires the positioning precision to nm - μm accuracy, thus the control system should be capable of the required precision positioning and attitude controls without producing contaminations from thruster exhaust plumes. A nanometer accuracy contaminationfree formation architecture, Photon Tether Formation Flight (PTFF), based on Photonic Laser Thrusters (PLTs) and tethers has been proposed to exploit a force equilibrium formed by PLT thrust and tether tension for forming precision persistent 3-D formation structures ideal for the large UV/Visible/IR space telescopes. The range of the PLT force can theoretically extend over several kms. Under previous NASA sponsorship, we have successfully demonstrated a proofof- concept PLT. In addition, the demonstrations of required laser components, optics and tracking technologies developed under military laser applications now support that implementation of PLTs for large space telescopes is one step closer to reality.

  11. 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.

  12. From monolithics to tethers to freeflyers: the spectrum of large aperture sensing from space

    NASA Astrophysics Data System (ADS)

    Leitner, Jesse; Quinn, Dave; Matsumura, Mark M.

    2003-02-01

    As part of The National Aeronautics and Space Administration's (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 space-based platforms that can permit this data gathering to occur. Observational data gathering is desired at a 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.

  13. 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.

  14. Characterizing the existing and potential structural space of proteins by large-scale multiple loop permutations

    PubMed Central

    Dai, Liang; Zhou, Yaoqi

    2011-01-01

    Worldwide structural genomics projects are increasing structure coverage of sequence space but have not significantly expanded the protein structure space itself (i.e. number of unique structural folds) since 2007. Discovering new structural folds experimentally by directed evolution and random recombination of secondary-structure blocks is also proved rarely successful. Meanwhile, previous computational efforts for large-scale mapping of protein structure space are limited to simple model proteins and led to an inconclusive answer on the completeness of the existing, observed protein structure space. Here, we build novel protein structures by extending naturally occurring circular (single-loop) permutation to multiple-loop permutations (MLP). These structures are clustered by structural similarity measure called TM-Score. The computational technique allows us to produce different structural clusters on the same naturally occurring, packed, stable core but with alternatively connected secondary-structure segments. A large-scale MLP of 2936 SCOP domains reproduces those existing structural clusters (63%) mostly as hubs for many non-redundant sequences and illustrates newly discovered novel clusters as islands adopted by a few sequences only. Results further show that there exist a significant number of novel, potentially stable clusters for medium or large-size single-domain proteins, in particular (>100 amino-acid residues) that are either not yet adopted by nature or adopted only by a few sequences. This study suggests that MLP provides a simple yet highly effective tool for engineering and design of novel protein structures (including naturally knotted proteins). The implication of recovering CASP new-fold targets by MLP on template-based structure prediction is also discussed. Our MLP structures are available for download at the publication page of the website http://sparks.informatics.iupui.edu. PMID:21376059

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

    2016-07-05

    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.

  20. COMPUTATIONAL METHODOLOGIES for REAL-SPACE STRUCTURAL REFINEMENT of LARGE MACROMOLECULAR COMPLEXES

    PubMed Central

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

    2017-01-01

    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

  1. 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.

  2. A general second order complete active space self-consistent-field solver for large-scale systems

    NASA Astrophysics Data System (ADS)

    Sun, Qiming; Yang, Jun; Chan, Garnet Kin-Lic

    2017-09-01

    We present a new second order complete active space self-consistent field implementation to converge wavefunctions for both large active spaces and large atomic orbital (AO) bases. Our algorithm decouples the active space wavefunction solver from the orbital optimization in the microiterations, and thus may be easily combined with various modern active space solvers. We also introduce efficient approximate orbital gradient and Hessian updates, and step size determination. We demonstrate its capabilities by calculating the low-lying states of the Fe(II)-porphine complex with modest resources using a density matrix renormalization group solver in a CAS(22, 27) active space and a 3000 AO basis.

  3. Advances in deployable structures and surfaces for large apertures in space

    NASA Astrophysics Data System (ADS)

    Santiago-Prowald, J.; Baier, H.

    2013-12-01

    Large apertures in space have applications for telecommunications, Earth observation and scientific missions. This paper reviews advances in mechanical architectures and technologies for large deployable apertures for space antennas and telescopes. Two complementary approaches are described to address this challenge: the deployment of structures based on quasi-rigid members and highly flexible structures. Regarding the first approach, deployable articulated structures are classified in terms of their kinematics as 3D or planar linkages in multiple variants, resulting in different architectures of radial, peripheral or modular constructions. A dedicated discussion on the number of degrees of freedom and constraints addresses the deployment reliability and thermo-elastic stability of large elastic structures in the presence of thermal gradients. This aspect has been identified as a design driver for new developments of peripheral ring and modular structures. Meanwhile, other design drivers are maintained, such as the optimization of mass and stiffness, overall accuracy and stability, and pragmatic aspects including controlled industrial development and a commitment to operators' needs. Furthermore, reflecting surface technologies and concepts are addressed with a view to the future, presenting advances in technical solutions for increasing apertures and reducing areal mass densities to affordable levels for future missions. Highly flexible materials capable of producing ultra-stable shells are described with reference to the state of the art and new developments. These concepts may enable large deployable surfaces for antennas and telescopes, as well as innovative optical concepts such as photon sieves. Shape adjustment and shape control of these surfaces are described in terms of available technologies and future needs, particularly for the reconfiguration of telecommunications antennas. In summary, the two complementary approaches described and reviewed cover the

  4. Preliminary results on the dynamics of large and flexible space structures in Halo orbits

    NASA Astrophysics Data System (ADS)

    Colagrossi, Andrea; Lavagna, Michèle

    2017-05-01

    The global exploration roadmap suggests, among other ambitious future space programmes, a possible manned outpost in lunar vicinity, to support surface operations and further astronaut training for longer and deeper space missions and transfers. In particular, a Lagrangian point orbit location - in the Earth- Moon system - is suggested for a manned cis-lunar infrastructure; proposal which opens an interesting field of study from the astrodynamics perspective. Literature offers a wide set of scientific research done on orbital dynamics under the Three-Body Problem modelling approach, while less of it includes the attitude dynamics modelling as well. However, whenever a large space structure (ISS-like) is considered, not only the coupled orbit-attitude dynamics should be modelled to run more accurate analyses, but the structural flexibility should be included too. The paper, starting from the well-known Circular Restricted Three-Body Problem formulation, presents some preliminary results obtained by adding a coupled orbit-attitude dynamical model and the effects due to the large structure flexibility. In addition, the most relevant perturbing phenomena, such as the Solar Radiation Pressure (SRP) and the fourth-body (Sun) gravity, are included in the model as well. A multi-body approach has been preferred to represent possible configurations of the large cis-lunar infrastructure: interconnected simple structural elements - such as beams, rods or lumped masses linked by springs - build up the space segment. To better investigate the relevance of the flexibility effects, the lumped parameters approach is compared with a distributed parameters semi-analytical technique. A sensitivity analysis of system dynamics, with respect to different configurations and mechanical properties of the extended structure, is also presented, in order to highlight drivers for the lunar outpost design. Furthermore, a case study for a large and flexible space structure in Halo orbits around

  5. 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

  6. 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

  7. Manufacture of large-scale lightweight SiC mirror for space

    NASA Astrophysics Data System (ADS)

    Huang, Zhengren; Liu, Guiling; Liu, Xuejian; Chen, Zhongming; Jiang, Dongliang

    2012-01-01

    Large-scale lightweight silicon carbide (SiC) mirrors were manufactured for space. Sintered SiC (SSiC) ceramic was adopted as the material to manufacture these mirrors. Complex structure designed for highly weight reduction and installation requirements was near-net-shape formed on SiC green body by digital machining technique before the high temperature sintering process. The dimensional accuracy of thin ribs and faceplate can be precisely controlled above 99.5%. During sintering process, the temperature distribution was kept uniform enough to avoid residual stress and deformation in the whole furnace. Isotropic shrinkage occurs during densification from SiC green body to ceramic with a fluctuation less than 0.3%, which is the dimension error of the final size as well. Mirror surface with low surface roughness, high shape accuracy and reflectivity was finished by polishing and plating. Moreover, large-scale lightweight SSiC mirror was demonstrated to be suitable for space use by tests simulating launch conditions and space environments.

  8. A Hybrid FEM-Continuous Approach for Modelling Large Space Structures for Attitude Control Synthesis

    NASA Astrophysics Data System (ADS)

    Monti, Riccardo; Gasbarri, Paolo

    In the last decade space agencies and industries have focused their attention on proposing and developing a new class of large space structures (LSS). LSS have potentially broad applications in space including low-stiffness precision shaped antennas for mobile communications satellites, narrow-band broadcast services and remote sensing, low-stiffness planar structures for large solar arrays. A lightweight design responding to the low gravity environment and live loads due to gravity gradients, extreme thermal variations, and solar wind create new and challenging problems in dynamic analysis of LSS. Since LSS will be designed for minimum weight and be quite flexible a significant problem will also arise on developing the capability to suppress and control flexible modes of vibration, some of which are closely packed with their frequencies that in turn could be very close to the ones of the attitude controller. On account of this it is necessary to have a very accurate model of the LSS. In the present work a hybrid FEM-continuous formulation, based on the classical modal reduction of a LSS under gravity and gravity gradient forces, will be presented. Analyses will be also performed to evaluate the effects of modal truncation on the robustness of attitude control laws.

  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. 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.

  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. 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

  13. 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).

  14. 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.

  15. 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.

  16. 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.

  17. Analysis of separation of the space shuttle orbiter from a large transport airplane

    NASA Technical Reports Server (NTRS)

    Wilhite, A. W.

    1977-01-01

    The feasibility of safely separating the space shuttle orbiter (140A/B) from the top of a large carrier vehicle (the C-5 airplane) at subsonic speeds was investigated. The longitudinal equations of motion for both vehicles were numerically integrated using a digital computer program which incorporates experimentally derived interference aerodynamic data to analyze the separation maneuver for various initial conditions. Separation of the space shuttle orbiter from a carrier vehicle was feasible for a range of dynamic-pressure and flight-path-angle conditions. By using an autopilot, the vehicle attitudes were held constant which ensured separation. Carrier-vehicle engine thrust, landing gear, and spoilers provide some flexibility in the separation maneuver.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Manufacturing and NDE of Large Composite Structures for Space Transportation at MSFC

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Russell, Sam

    2000-01-01

    This paper presents the Marshall Space Flight Center's (MSFC's) vision to manufacture, increase safety and reduce the cost of launch vehicles. Nondestructive evaluations of large composite structures are tested for space transportation at MSFC. The topics include: 1) 6 1/2 Generations of Airplanes in a Century; 2) Shuttle Safety Upgrades; 3) Generations of Reusable Launch Vehicles; 4) RLV Technology Demonstration Path; 5) Second Generation; 6) Key NASA Requirements; 7) X-33 Elements; 8) Future-X Pathfinder Projects and Experiments; 9) Focus Area Technical Goals; 10) X-34 Expanded View; 11) X-38 Spacecraft with De-Orbit Propulsion Stage (DPS); 12) Deorbit Module (DM) Critical Design Review (CDR) Design; 13) Forward Structural Adapter (FSA) CDR Design; 14) X-38 DPS CDR Design; 15) RLV Focused Propulsion Technologies; and 16) Challenges in Technology. This paper is presented in viewgraph form.

  4. 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.

  5. Megamap: flexible representation of a large space embedded with nonspatial information by a hippocampal attractor network

    PubMed Central

    Zhang, Kechen

    2016-01-01

    The problem of how the hippocampus encodes both spatial and nonspatial information at the cellular network level remains largely unresolved. Spatial memory is widely modeled through the theoretical framework of attractor networks, but standard computational models can only represent spaces that are much smaller than the natural habitat of an animal. We propose that hippocampal networks are built on a basic unit called a “megamap,” or a cognitive attractor map in which place cells are flexibly recombined to represent a large space. Its inherent flexibility gives the megamap a huge representational capacity and enables the hippocampus to simultaneously represent multiple learned memories and naturally carry nonspatial information at no additional cost. On the other hand, the megamap is dynamically stable, because the underlying network of place cells robustly encodes any location in a large environment given a weak or incomplete input signal from the upstream entorhinal cortex. Our results suggest a general computational strategy by which a hippocampal network enjoys the stability of attractor dynamics without sacrificing the flexibility needed to represent a complex, changing world. PMID:27193320

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

    PubMed

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

    2017-03-10

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

  7. 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.

  8. 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.

  9. New Motion System Development and Rotary Nitrogen Joint Qualification for ESA ESTEC Large Space Simulator (LSS)

    NASA Astrophysics Data System (ADS)

    Messing, R.; Tanchon, J.; Trollier, T.; Hervieu, M.

    2014-06-01

    ESA Test Centre at ESTEC, Noordwijk is a unique place in Europe, which is geared to perform environmental tests on large spacecraft at system level. The Test Centre includes the whole environmental facilities family: shakers, acoustic chamber, mass properties measurement facilities, electro-magnetic compatibility facilities and thermal vacuum chambers. The largest of the thermal vacuum chambers is called Large Space Simulator (LSS) and is the largest one of its kind in Europe.This paper describes the current activity related to the upgrade of the Large Space Simulator (LSS) with the New Motion System (NMS). The NMS will allow various orientations of the specimen with respect to the LSS fixed sun illumination. Specific components have been developed and qualified during the development phase of the NMS. One of them is a multi-turn Rotary Nitrogen Joint (RNJ) used to distribute nitrogen on all thermal shrouds covering the NMS structure. Nitrogen flexible hoses were not suitable for the NMS due to the size required to cover the three rotational degrees of freedom. This paper focuses on the design of the New Motion System with specific highlight on the Rotary Nitrogen Joint development and qualification against thermal vacuum conditions used for spacecraft thermal testing.

  10. 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).

  11. 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).

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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 literature in the fields of structural identification, mode shape expansion and orthogonalization, and on-orbit damage location of large space trusses is reviewed. The use of a Dynamic Scale Model Technology (DSMT) hybrid scale model for damage location research and as a universal test bed for other damage location methods is proposed as a means of comparing and evaluating existing and newly developed methods in the named areas. Issues concerning on-orbit data acquisition, data accuracy, and data quality relevant to structural dynamic system identification which require extensive research are identified.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  19. 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.

  20. 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.

  1. 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.

  2. Technology for Large Space Systems: A Special Bibliography with Indexes (Supplement 2)

    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.

  3. 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.

  4. 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 literature in the fields of structural identification, mode shape expansion and orthogonalization, and on-orbit damage location of large space trusses is reviewed. The use of a Dynamic Scale Model Technology (DSMT) hybrid scale model for damage location research and as a universal test bed for other damage location methods is proposed as a means of comparing and evaluating existing and newly developed methods in the named areas. Issues concerning on-orbit data acquisition, data accuracy, and data quality relevant to structural dynamic system identification which require extensive research are identified.

  5. 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.

  6. 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.

  7. Collimator equipment of the Large Optical Test Facility Vertical for testing space telescopes

    NASA Astrophysics Data System (ADS)

    Sergeev, Pavel A.; Gogolev, Yuri A.; Zvonkova, V. V.; Kobozev, I. R.; Ostapenko, S. V.; Malamed, Evgeny R.; Demidov, V. V.

    1995-06-01

    This paper is concerned with the collimator equipment of the large optical test facility (LOTF) 'vertical' designed for testing space telescopes. It is being created in the Research Center 'S.I. Vavilov State Optical Institute' in Russia. The optical scheme and special structural features of the vacuum vertical-type double-mirror collimator will be covered here. This paper deals with technical data and potentials of collimator focal equipment. Estimations of the collimator thermal aberrations caused by temperature fields coming from thermal simulators are put forward.

  8. 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

  9. Plans for a large deployable reflector for submillimeter and infrared astronomy from space

    NASA Technical Reports Server (NTRS)

    Swanson, P. N.; Breckinridge, J. B.; Gulkis, S.; Kuiper, T. B. H.; Kiya, M.

    1982-01-01

    Continuing plans for a large deployable reflector (LDR), conceived as a 10- to 30-m-diameter clear-aperture telescope, operating at wavelengths from 1000 microns to a diffraction-limited 30 microns, and to be placed in orbit for a life of 10 years by the Space Shuttle, are discussed. The primary reflector will be composed of a number of closely packed hexagonal segments of glass or lightweight composite material and attached to a truss integrating structure through position actuators providing three degrees of freedom for each segment. Technical aspects of optical design, surface measurement systems, deployment, and detectors are discussed, as are practical and fiscal limitations.

  10. Optimal fine pointing control of a large space telescope using an Annular Momentum Control Device

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    This paper discusses the application of an Annular Momentum Control Device (AMCD) to fine pointing control of a large space telescope (LST). The AMCD represents a new development in the field of momentum storage devices. A linearized mathematical model is developed for the AMCD/LST system, including the magnetic suspension actuators. Two approaches to control system design are considered. The first approach uses a stochastic linear-quadratic Gaussian controller which utilizes feedback of all states. The second approach considers a more practical control system design in which the axial and radial loops are designed independently.

  11. 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.

  12. 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.

  13. 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.

  14. 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).

  15. Stability analysis of large space structure control systems with delayed input

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Large space structural systems, due to their inherent flexibility and low mass to area ratio, are represented by large dimensional mathematical models. For implementation of the control laws for such systems a finite amount of time is required to evaluate the control signals; and this time delay may cause instability in the closed loop control system that was previously designed without taking the input delay into consideration. The stability analysis of a simple harmonic oscillator representing the equation of a single mode as a function of delay time is analyzed analytically and verified numerically. The effect of inherent damping on the delay is also analyzed. The control problem with delayed input is also formulated in the discrete time domain.

  16. Stability analysis of large space structure control systems with delayed input

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Large space structural systems, due to their inherent flexibility and low mass to area ratio, are represented by large dimensional mathematical models. For implementation of the control laws for such systems a finite amount of time is required to evaluate the control signals; and this time delay may cause instability in the closed loop control system that was previously designed without taking the input delay into consideration. The stability analysis of a simple harmonic oscillator representing the equation of a single mode as a function of delay time is treated analytically and verified numerically. The effect of inherent damping on the delay is also analyzed. The control problem with delayed input is also formulated in the discrete time domain.

  17. 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.

  18. 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.

  19. Rapidly eliminating pathogenic microorganisms in large air space using spraying *OH radicals.

    PubMed

    Bai, Mindong; Zhang, Zhitao; Tian, Yiping; Bai, Mindi

    2012-04-01

    A new method for rapidly eliminating pathogenic microorganisms in large air space using spraying *OH radicals is presented in this paper With a physical method of strong electric-field discharge, large numbers of *OH radicals were produced by the oxygen activated particles of O2+, O(1D), O(3P), etc., and the introducing reagent HO2-. The gram-positive bacteria Bacillus subtilis, the gram-negative bacteria Serratia marcescens, and Bacillus spores were used for the eliminating experiments. Results show that the different microorganisms were rapidly killed by *OH radicals with a concentration of 0.8 mg/L and spraying density of 21 microL/m2 within 4 sec. Cell morphological changes were also observed under microscope. The cells of B. subtilis and Bacillus spores in their cellular wall, cellular membrane, or cell protoplasm were greatly destroyed when being exposed to a killing dosage of *OH radicals.

  20. Landscape of supersymmetric particle mass hierarchies and their signature space at the CERN Large Hadron Collider.

    PubMed

    Feldman, Daniel; Liu, Zuowei; Nath, Pran

    2007-12-21

    The minimal supersymmetric standard model with soft breaking has a large landscape of supersymmetric particle mass hierarchies. This number is reduced significantly in well-motivated scenarios such as minimal supergravity and alternatives. We carry out an analysis of the landscape for the first four lightest particles and identify at least 16 mass patterns, and provide benchmarks for each. We study the signature space for the patterns at the CERN Large Hadron Collider by analyzing the lepton+ (jet> or =2) + missing P{T} signals with 0, 1, 2, and 3 leptons. Correlations in missing P{T} are also analyzed. It is found that even with 10 fb{-1} of data a significant discrimination among patterns emerges.