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Sample records for microgravity vibration isolation

  1. Fundamentals of Microgravity Vibration Isolation

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.

    2000-01-01

    In view of the utility of space vehicles as orbiting science laboratories, the need for vibration isolation systems for acceleration sensitive experiments has gained increasing visibility. This presentation provides a tutorial discussion of microgravity vibration isolation technology with the objective of elaborating on the relative merits of passive and active isolation approaches. The concepts of control bandwidth, isolation performance, and robustness will be addressed with illustrative examples. Concluding the presentation will be a suggested roadmap for future technology development activities to enhance the acceleration environment for microgravity science experiments.

  2. Payload vibration isolation in a microgravity environment

    NASA Technical Reports Server (NTRS)

    Alexander, Richard M.

    1990-01-01

    Many in-space research experiments require the microgravity environment attainable near the center of mass of the Space Station. Disturbances to the structure surrounding an experiment may lead to vibration levels that will degrade the microgravity environment and undermine the experiment's validity. In-flight disturbances will include vibration transmission from nearby equipment and excitation from crew activity. Isolation of these vibration-sensitive experiments is required. Analytical and experimental work accomplished to develop a payload (experiment) isolation system for use in space is described. The isolation scheme allows the payload to float freely within a prescribed boundary while being kept centered with forces generated by small jets of air. The vibration criterion was a maximum payload acceleration of 10 micro-g's (9.81x10(exp -5)m/s(exp 2), independent of frequency. An experimental setup, composed of a cart supported by air bearings on a flat granite slab, was designed and constructed to simulate the microgravity environment in the horizontal plane. Experimental results demonstrate that the air jet control system can effectively manage payload oscillatory response. An analytical model was developed and verified by comparing predicted and measured payload response. The mathematical model, which includes payload dynamics, control logic, and air jet forces, is used to investigate payload response to disturbances likely to be present in the Space Station.

  3. International Workshop on Vibration Isolation Technology for Microgravity Science Applications

    NASA Technical Reports Server (NTRS)

    Lubomski, Joseph F. (Editor)

    1992-01-01

    The International Workshop on Vibration Isolation Technology for Microgravity Science Applications was held on April 23-25, 1991 at the Holiday Inn in Middleburg Heights, Ohio. The main objective of the conference was to explore vibration isolation requirements of space experiments and what level of vibration isolation could be provided both by present and planned systems on the Space Shuttle and Space Station Freedom and by state of the art vibration isolation technology.

  4. Survey of Active Vibration Isolation Systems for Microgravity Applications

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.; Whorton, Mark S.

    2000-01-01

    In view of the utility of space vehicles as orbiting science laboratories, the need for vibration isolation systems for acceleration-sensitive experiments has gained increasing visibility. To date, three active microgravity vibration isolation systems have successfully been demonstrated in flight. A tutorial discussion of the microgravity vibration isolation problem, including a description of the acceleration environment of the International Space Station and attenuation requirements, as well as a comparison or the dynamics of passive isolation, active rack-level isolation, and active payload-level isolation is provided. The flight test results of the three demonstrated systems: suppression of transient accelerations by levitation, the microgravity vibration isolation mount, and the active rack isolation system are surveyed.

  5. A Survey of Active Vibration Isolation Systems for Microgravity Applications

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.; Whorton, Mark S.

    2000-01-01

    In view of the utility of space vehicles as orbiting science laboratories, the need for vibration isolation systems for acceleration sensitive experiments has gained increasing visibility. To date, three active microgravity vibration isolation systems have successfully been demonstrated in flight. This paper provides a tutorial discussion of the microgravity vibration isolation problem including a description of the acceleration environment of the International Space Station and attenuation requirements as well as a comparison of the dynamics of passive isolation, active rack-level isolation, and active payload-level isolation. This paper also surveys the flight test results of the three demonstrated systems: Suppression of Transient Accelerations By Levitation (STABLE); the Microgravity Vibration Isolation Mount (MIM); and the Active Rack Isolation System (ARIS).

  6. Microgravity Vibration Isolation for the International Space Station

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.

    2000-01-01

    The International Space Station (ISS) is being envisioned as a laboratory for experiments in numerous microgravity (micrograms) science disciplines. Predictions of the ISS acceleration environment indicate that the ambient acceleration levels ill exceed levels that can be tolerated by the science experiments. Hence, microgravity vibration isolation systems are being developed to attenuate the accelerations to acceptable levels. While passive isolation systems are beneficial in certain applications, active isolation systems are required to provide attenuation at low frequencies and to mitigate directly induced payload disturbances. To date, three active isolation systems have been successfully tested in the orbital environment. A fourth system called g-LIMIT is currently being developed for the Microgravity Science Glovebox and is manifested for launch on the UF-1 mission. This paper presents an overview of microgravity vibration isolation technology and the g-LIMIT system in particular.

  7. Limitations on vibration isolation for microgravity space experiments

    NASA Technical Reports Server (NTRS)

    Knospe, C.; Allaire, P.

    1990-01-01

    The vibration-isolation limitations of spaceborne microgravity experiments are largely due to isolation-system volume restrictions. In the present one-degree-of-freedom representation of an experimental aircraft, assuming an ideal vibration actuator, wall motion is characterized as sinusoidal at a single frequency. The result is a kinematic representation which poses the problem of the minimum acceleration trajectory within a pair of moving walls; analysis then yields a simple condition under which a closed-form solution is available. The results obtained demonstrate that isolation from low-frequency vibration requires more interior space than is available for vibration isolation on manned orbiters.

  8. A TREETOPS Simulation of the STABLE Microgravity Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Nurre, G. S.; Whorton, M. S.; Kim, Y. K.

    1999-01-01

    As a research facility for microgravity science, the International Space Station (ISS) will be used for numerous experiments which require a quiescent acceleration environment across a broad spectrum of frequencies. For many micro-gravity science experiments, the ambient acceleration environment on ISS will significantly exceed desirable levels. The ubiquity of acceleration disturbance sources and the difficulty in characterization of these sources precludes source isolation, requiring, vibration isolation to attenuate the disturbances to an acceptable level at the experiment. To provide a more quiescent acceleration environment, a vibration isolation system named STABLE (Suppression of Transient Accelerations By LEvitation) was developed. STABLE was the first successful flight test of an active isolation device for micro-gravity science payloads and was flown on STS-73/USML-2 in October 1995. This report documents the development of the high fidelity, nonlinear, multibody simulation developed using TREETOPS which was used to design the control laws and define the expected performance of the STABLE isolation system.

  9. Microgravity Vibration Isolation System Based on Parallel Kinematic Communications

    NASA Astrophysics Data System (ADS)

    Russkin, Alexander; Postojuk, Nikolay

    The paper is devoted to the construction of an active vibration isolation system of experimental and technological equipment operating in microgravity conditions. Space experiments associated with obtaining ultrapure materials are required the residual level of microgravity vibration from mmug to mg at the frequency range from 0.01 Hz to 100 Hz in the experiment area. This residual level of microgravity vibration is difficult to achieve by conventional passive protection systems. To date the different types of active vibration isolation systems are constructed, such as STABLE, ARIS, MIM, g-LIMIT and MVIS, but their characteristics and geometrical parameters do not always satisfy the given technological requirements. In this paper, the mechanism with parallel kinematic constraints (MPKS) is proposed for constructing microgravity active vibration isolation system, which provides protection against vibrations in six degrees of freedom and can be scaled depending on the specific tasks. MPKS distinguishing feature is the presence of closed kinematic chain, which provide high rigidity of the structure, reduce the mass of moving parts and reduce the load on the actuator. As a result, this increases the dynamics and positioning accuracy MPKS. The proposed version of microgravity vibration isolation system consists of two main parts: the electromechanical assembly and control unit. The main specifications for the constituent parts of the system are defined. A comparative analysis of different types of actuators and sensors for electromechanical assembly is carried out. The appropriate components to provide the desired specifications are selected. There are proposed to use piezoelectric motors as actuators in electromechanical assembly. Mathematical models of MPKS with six degrees of freedom and control system are considered. The structure of the control system and controller type is selected. A mathematical model of proposed microgravity vibration isolation system is

  10. Adaptive Control for Microgravity Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Yang, Bong-Jun; Calise, Anthony J.; Craig, James I.; Whorton, Mark S.

    2005-01-01

    Most active vibration isolation systems that try to a provide quiescent acceleration environment for space science experiments have utilized linear design methods. In this paper, we address adaptive control augmentation of an existing classical controller that employs a high-gain acceleration feedback together with a low-gain position feedback to center the isolated platform. The control design feature includes parametric and dynamic uncertainties because the hardware of the isolation system is built as a payload-level isolator, and the acceleration Sensor exhibits a significant bias. A neural network is incorporated to adaptively compensate for the system uncertainties, and a high-pass filter is introduced to mitigate the effect of the measurement bias. Simulations show that the adaptive control improves the performance of the existing acceleration controller and keep the level of the isolated platform deviation to that of the existing control system.

  11. Microgravity Active Vibration Isolation System on Parabolic Flights

    NASA Astrophysics Data System (ADS)

    Dong, Wenbo; Pletser, Vladimir; Yang, Yang

    2016-07-01

    The Microgravity Active Vibration Isolation System (MAIS) aims at reducing on-orbit vibrations, providing a better controlled lower gravity environment for microgravity physical science experiments. The MAIS will be launched on Tianzhou-1, the first cargo ship of the China Manned Space Program. The principle of the MAIS is to suspend with electro-magnetic actuators a scientific payload, isolating it from the vibrating stator. The MAIS's vibration isolation capability is frequency-dependent and a decrease of vibration of about 40dB can be attained. The MAIS can accommodate 20kg of scientific payload or sample unit, and provide 30W of power and 1Mbps of data transmission. The MAIS is developed to support microgravity scientific experiments on manned platforms in low earth orbit, in order to meet the scientific requirements for fluid physics, materials science, and fundamental physics investigations, which usually need a very quiet environment, increasing their chances of success and their scientific outcomes. The results of scientific experiments and technology tests obtained with the MAIS will be used to improve future space based research. As the suspension force acting on the payload is very small, the MAIS can only be operative and tested in a weightless environment. The 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, German Aerospace Centre) granted a flight opportunity to the MAIS experiment to be tested during its 27th parabolic flight campaign of September 2015 performed on the A310 ZERO-G aircraft managed by the French company Novespace, a subsidiary of the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency). The experiment results confirmed that the 6 degrees of freedom motion control technique was effective, and that the vibration isolation performance fulfilled perfectly the expectations based on theoretical analyses and simulations. This paper will present the design of the MAIS and the experiment results obtained during the

  12. The g-LIMIT Microgravity Vibration Isolation System for the Microgravity Science Glovebox

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.; Ryan, Stephen G. (Technical Monitor)

    2001-01-01

    For many microgravity science experiments in the International Space Station, the ambient acceleration environment will be exceed desirable levels. To provide a more quiescent acceleration environment to the microgravity payloads, a vibration isolation system named g-LIMIT (GLovebox Integrated Microgravity Isolation Technology) is being designed. g-LIMIT is a sub-rack level isolation system for the Microgravity Science Glovebox that can be tailored to a variety of applications. Scheduled for launch on the UF-1 mission, the initial implementation of g-LIMIT will be a Characterization Test in the Microgravity Science Glovebox. g-LIMIT will be available to glovebox investigators immediately after characterization testing. Standard MSG structural and umbilical interfaces will be used so that the interface requirements are minimized. g-LIMIT consists of three integrated isolator modules, each of which is comprised of a dual axis actuator, two axes of acceleration sensing, two axes of position sensing, control electronics, and data transmission capabilities in a small-volume package. In addition, this system provides the unique capability for measuring quasi-steady acceleration of the experiment independent of accelerometers as a by-product of the control system and will have the capability of generating user-specified pristine accelerations to enhance experiment operations.

  13. Equations of Motion for the g-LIMIT Microgravity Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Kim, Y. K.; Whorton, M. S.

    2001-01-01

    A desirable microgravity environment for experimental science payloads may require an active vibration isolation control system. A vibration isolation system named g-LIMIT (GLovebox Integrated Microgravity Isolation Technology) is being developed by NASA Marshall Space Flight Center to support microgravity science experiments using the microgravity science glovebox. In this technical memorandum, the full six-degree-of-freedom nonlinear equations of motion for g-LIMIT are derived. Although the motivation for this model development is control design and analysis of g-LIMIT, the equations are derived for a general configuration and may be used for other isolation systems as well.

  14. Voice Coil Actuator for Active Vibration Isolation in Microgravity

    NASA Astrophysics Data System (ADS)

    Brusa, E.; Carabelli, S.; Genta, G.; Maddaleno, F.; Silvagni, M.; Tonoli, A.

    2002-01-01

    Many microgravity experiments require very low levels of acceleration which cannot be achieved on the International Space Station due to the residual vibration. A vibration isolation system is then usually devised between the experiment and the space station to obtain the desired accelerations at the experiment level. The very low frequency threshold required by the isolation specifications makes passive solutions for the isolation difficult to implement. This is mainly due to the practical impossibility of achieving high values of compliance of the elastic suspension. Furthermore, the unavoidable connections of uncertain characteristics between the experiment and the space station makes the problem even more difficult to be addressed. Disturbance reduction can be performed by means of active vibration isolation, based on magnetic suspension technology acting both at rack and at scientific experiment levels. The stiffness and damping of the active suspension can be tuned by the control loop to minimise the acceleration of the payload. The mechatronic design of an active magnetic suspension for vibration isolation in microgravity has been performed by resorting to the so-called voice-coil configuration, after a preliminary trade-off analysis of the available magnetic actuators and materials. The optimisation of the actuator layout was developed with respect to the design airgap and force density (N/kg of actuator) and force resolution requirements, by demonstrating that the configuration based on Lorentz magnetic force is more suitable for the above application in terms of stability, bi- directionality of the actuation, cross coupling effects and linearity of the force. The aim of the design was the maximisation of the actuation force/mass ratio. The FEM analysis of the voice coil allowed to investigate the flux leakage and the cross coupling effects between the actuation forces along the three principal directions of the active device. A procedure for the numerical

  15. Nonintrusive inertial vibration isolation technology for microgravity space experiments

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.; Brown, Gerald V.

    1989-01-01

    The dynamic acceleration environment observed on Space Shuttle flights to date and predicted for the Space Station has complicated the analysis of prior microgravity experiments and prompted concern for the viability of proposed space experiments requiring long-term, microgravity environments. Isolation systems capable of providing significant improvements to this environment exist, but at present have not been demonstrated in flight configurations. A summary of the theoretical evaluation for two one degree-of-freedom (DOF) active magnetic isolators and their predicted response to both direct and base excitations is presented. These isolators can be used independently or in concert to isolate acceleration-sensitive microgravity space experiments, dependent on the isolation capability required for specific experimenter needs.

  16. Utilizing Advanced Vibration Isolation Technology to Enable Microgravity Science Operations

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean Carl

    1999-01-01

    Microgravity scientific research is performed in space to determine the effects of gravity upon experiments. Until recently, experiments had to accept the environment aboard various carriers: reduced-gravity aircraft, sub-orbital payloads, Space Shuttle, and Mir. If the environment is unacceptable, then most scientists would rather not expend the resources without the assurance of true microgravity conditions. This is currently the case on the International Space Station, because the ambient acceleration environment will exceed desirable levels. For this reason, the g-LIMIT (Glovebox Integrated Microgravity Isolation Technology) system is currently being developed to provide a quiescent acceleration environment for scientific operations. This sub-rack isolation system will provide a generic interface for a variety of experiments for the Microgravity Science Glovebox. This paper describes the motivation for developing of the g-LIMIT system, presents the design concept and details some of the advanced technologies utilized in the g-LIMIT flight design.

  17. Low frequency vibration isolation technology for microgravity space experiments

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.; Brown, Gerald V.

    1989-01-01

    The dynamic acceleration environment observed on Space Shuttle flights to date and predicted for the Space Station has complicated the analysis of prior microgravity experiments and prompted concern for the viability of proposed space experiments requiring long-term, low-g environments. Isolation systems capable of providing significant improvements in this environment exist, but have not been demonstrated in flight configurations. This paper presents a summary of the theoretical evaluation for two one degree-of-freedom (DOF) active magnetic isolators and their predicted response to both direct and base excitations, that can be used to isolate acceleration sensitive microgravity space experiments.

  18. Vibration isolation

    NASA Technical Reports Server (NTRS)

    Bastin, Paul

    1990-01-01

    Viewgraphs on vibration isolation are presented. Techniques to control and isolate centrifuge disturbances were identified. Topics covered include: disturbance sources in the microgravity environment; microgravity assessment criteria; life sciences centrifuge; flight support equipment for launch; active vibration isolation system; active balancing system; and fuzzy logic control.

  19. Results of the Stable Microgravity Vibration Isolation Flight Experiment

    NASA Technical Reports Server (NTRS)

    Edberg, Donald; Boucher, Robert; Schenck, David; Nurre, Gerald; Whorton, Mark; Kim, Young; Alhorn, Dean

    1996-01-01

    This paper presents an overview of the STABLE microgravity isolation system developed and successfully flight tested in October 1995. A description of the hardware design and operational principles is given. A sample of the measured flight data is presented, including an evaluation of attenuation performance provided by the actively controlled electromagnetic isolation system. Preliminary analyses of flight data show that the acceleration environment aboard STABLE's isolated platform was attenuated by a factor of more than 25 between 0.1 and 100 Hz. STABLE was developed under a cooperative agreement between National Aeronautics and Space Administration, Marshall Space Flight Center, and McDonnell Douglas Aerospace. The flight hardware was designed, fabricated, integrated, tested, and delivered to the Cape during a five month period.

  20. Microgravity vibration isolation: Optimal preview and feedback control

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Knospe, C. R.; Grodsinsky, C. M.; Allaire, P. E.; Lewis, D. W.

    1992-01-01

    In order to achieve adequate low-frequency vibration isolation for certain space experiments an active control is needed, due to inherent passive-isolator limitations. Proposed here are five possible state-space models for a one-dimensional vibration isolation system with a quadratic performance index. The five models are subsets of a general set of nonhomogeneous state space equations which includes disturbance terms. An optimal control is determined, using a differential equations approach, for this class of problems. This control is expressed in terms of constant, Linear Quadratic Regulator (LQR) feedback gains and constant feedforward (preview) gains. The gains can be easily determined numerically. They result in a robust controller and offers substantial improvements over a control that uses standard LQR feedback alone.

  1. Robust Control for Microgravity Vibration Isolation using Fixed Order, Mixed H2/Mu Design

    NASA Technical Reports Server (NTRS)

    Whorton, Mark

    2003-01-01

    Many space-science experiments need an active isolation system to provide a sufficiently quiescent microgravity environment. Modern control methods provide the potential for both high-performance and robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H(infinity) methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/H(infinity), controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure, for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

  2. Robust Control for The G-Limit Microgravity Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.

    2004-01-01

    Many microgravity science experiments need an active isolation system to provide a sufficiently quiescent acceleration environment. The g-LIMIT vibration isolation system will provide isolation for Microgravity Science Glovebox experiments in the International Space Station. While standard control system technologies have been demonstrated for these applications, modern control methods have the potential for meeting performance requirements while providing robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H infinity methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/mu controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

  3. A new approach to active vibration isolation for microgravity space experiments

    NASA Technical Reports Server (NTRS)

    Sinha, Alok; Kao, Chikuan K.; Grodsinsky, Carlos M.

    1990-01-01

    A new method was developed to design an active vibration isolation system for microgravity space experiments. This method yields the required controller transfer functions for a specified transmissibility ratio. Hence, it is a straightforward task to guarantee that the desired vibration isolation performance is achieved at each frequency. The theory for such a controller design was presented by considering a single degree of freedom system. In addition, the magnitude of the input required by the new method has been found to be less than that used by a standard phase lead/lag compensator.

  4. Active Vibration Isolation of Microgravity Experiments with Spring Umbilicals Using an Electrodynamic Actuator

    NASA Technical Reports Server (NTRS)

    Banerjee, B. B.; Allaire, P. E.; Grodsinsky, C. M.

    1996-01-01

    Microgravity experiments will require active vibration isolation in the low to mid frequency range of 0.1 Hz to 10 Hz. Approximately two orders of acceleration reduction (40 dB) will be required. Previous works have reported results for accelerations transmitted through the umbilical. This paper describes experimental and theoretical results for vibration isolation in one dimension (horizontal) where the simulated experiment is connected to the spacecraft by a spring umbilical. The experiment consisted of a spacecraft (shaker), experiment (mass), umbilical, accelerometer, control electronics, and Lorentz actuator. The experiment mass was supported in magnetic bearings to avoid any stiction problems. Acceleration feedback control was employed to obtain the vibration isolation. Three different spring umbilicals were employed. Acceleration reductions on the order of 40 dB were obtained over the frequency range of 0.1 Hz to 10 Hz. Good agreement was obtained between theory and experiment.

  5. The Microgravity Vibration Isolation Mount: A Dynamic Model for Optimal Controller Design

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Tryggvason, Bjarni V.; DeCarufel, Jean; Townsend, Miles A.; Wagar, William O.

    1997-01-01

    Vibration acceleration levels on large space platforms exceed the requirements of many space experiments. The Microgravity Vibration Isolation Mount (MIM) was built by the Canadian Space Agency to attenuate these disturbances to acceptable levels, and has been operational on the Russian Space Station Mir since May 1996. It has demonstrated good isolation performance and has supported several materials science experiments. The MIM uses Lorentz (voice-coil) magnetic actuators to levitate and isolate payloads at the individual experiment/sub-experiment (versus rack) level. Payload acceleration, relative position, and relative orientation (Euler-parameter) measurements are fed to a state-space controller. The controller, in turn, determines the actuator currents needed for effective experiment isolation. This paper presents the development of an algebraic, state-space model of the MIM, in a form suitable for optimal controller design.

  6. g-LIMIT: A Vibration Isolation System for the Microgravity Science Glovebox

    NASA Technical Reports Server (NTRS)

    Whorton, Mark S.

    1998-01-01

    For many microgravity science experiments using the Microgravity Science Glovebox (MSG), the ambient acceleration environment will exceed desirable levels. To provide a more quiescent acceleration environment, a vibration isolation system named g-LIMIT (GLovebox Integrated Microgravity Isolation Technology) is being designed. g-LIMIT is the next generation of technology developed for and demonstrated by STABLE on the USML-2 mission in October 1995. Although g-LIMIT is a sub-rack level isolation system that can be used in a variety of applications, g-LIMIT is uniquely optimized for MSG implementation. Standard MSG structural and umbilical interfaces will be used so that the isolation mount is transparent to the user with no additional accommodation requirements. g-LIMIT consists of three integrated isolator modules, each of which is comprised of a dual axis actuator, two axes of acceleration sensing, two axes of position sensing, control electronics, and data transmission capabilities in a minimum-volume package. In addition, this system provides the unique capability for measuring absolute acceleration of the experiment independent of accelerometers as a by-product of the control system and will have the capability of generating pristine accelerations to enhance experiment operations. g-LIMIT is scheduled for flight during the UF-2 mission and will be available to glovebox investigators immediately after characterization testing.

  7. Limits on the isolation of stochastic vibration for microgravity space experiments

    NASA Technical Reports Server (NTRS)

    Knospe, C. R.; Allaire, P. E.

    1991-01-01

    The limitations on the isolation of stochastic vibrations for microgravity space experiments are explored. These limitations result from the restricted interior space available for vibration isolation. A one-degree-of-freedom representation of the experiment-spacecraft system is used, and an ideal vibration actuator is assumed. A kinematic representation results, and the problem becomes one of finding the minimum acceleration trajectory within a pair of stochastic walls. The wall motion is characterized by an ergodic, stationary, zero-mean, Gaussian random process with known power spectral density. The geometry of the wall trajectories is defined in terms of their significant extrema and zero crossings. This geomemtry is used in defining a composite trajectory that has a mean square acceleratiaon lower than that on the optimal path satisfying the stochastic wall inequality constraints. The optimal control problem is solved on a return path yielding the mean square acceleration in terms of the distributions of significant maxima and first-passage time of the wall process. The methodology is applied to a microgravity isolation problem to find the lower bounds on root-mean-square acceleration given the disturbance power spectral density.

  8. A six degree-of-freedom magnetic bearing for microgravity vibration isolation

    NASA Technical Reports Server (NTRS)

    Allan, A. Peter; Knospe, Carl R.

    1992-01-01

    A design for a magnetic bearing, proposed as the fine stage of a coarse-fine actuator for microgravity vibration isolation, is presented. The bearing is novel in that it uses a geometry that has just three independent flux path systems. This contrasts the twelve flux path systems (six bidirectional thrust bearings) used in conventional designs. The design results in compactness, light weight, and high performance when compared with the published designs. A control system is proposed to reject disturbances caused by an umbilical connection to the experiment.

  9. A six degree-of-freedom magnetic bearing for microgravity vibration isolation

    NASA Astrophysics Data System (ADS)

    Allan, A. Peter; Knospe, Carl R.

    1992-05-01

    A design for a magnetic bearing, proposed as the fine stage of a coarse-fine actuator for microgravity vibration isolation, is presented. The bearing is novel in that it uses a geometry that has just three independent flux path systems. This contrasts the twelve flux path systems (six bidirectional thrust bearings) used in conventional designs. The design results in compactness, light weight, and high performance when compared with the published designs. A control system is proposed to reject disturbances caused by an umbilical connection to the experiment.

  10. Damping Mechanisms for Microgravity Vibration Isolation (MSFC Center Director's Discretionary Fund Final Report, Project No. 94-07)

    NASA Technical Reports Server (NTRS)

    Whorton, M. S.; Eldridge, J. T.; Ferebee, R. C.; Lassiter, J. O.; Redmon, J. W., Jr.

    1998-01-01

    As a research facility for microgravity science, the International Space Station (ISS) will be used for numerous investigations such as protein crystal growth, combustion, and fluid mechanics experiments which require a quiescent acceleration environment across a broad spectrum of frequencies. These experiments are most sensitive to low-frequency accelerations and can tolerate much higher accelerations at higher frequency. However, the anticipated acceleration environment on ISS significantly exceeds the required acceleration level. The ubiquity and difficulty in characterization of the disturbance sources precludes source isolation, requiring vibration isolation to attenuate the anticipated disturbances to an acceptable level. This memorandum reports the results of research in active control methods for microgravity vibration isolation.

  11. Fluids and Materials Science Studies Utilizing the Microgravity-vibration Isolation Mount (MIM)

    NASA Technical Reports Server (NTRS)

    Herring, Rodney; Tryggvason, Bjarni; Duval, Walter

    1998-01-01

    Canada's Microgravity Sciences Program (MSP) is the smallest program of the ISS partners and so can participate in only a few, highly focused projects in order to make a scientific and technological impact. One focused project involves determining the effect of accelerations (g-jitter) on scientific measurements in a microgravity environment utilizing the Microgravity-vibration Isolation Mount (MIM). Many experiments share the common characteristic of having a fluid stage in their process. The quality of the experimental measurements have been expected to be affected by g-jitters which has lead the ISS program to include specifications to limit the level of acceleration allowed on a subset of experimental racks. From finite element analysis (FEM), the ISS structure will not be able to meet the acceleration specifications. Therefore, isolation systems are necessary. Fluid science results and materials science results show significant sensitivity to g-jitter. The work done to date should be viewed only as a first look at the issue of g-jitter sensitivity. The work should continue with high priority such that the international science community and the ISS program can address the requirement and settle on an agreed to overall approach as soon as possible.

  12. Fluids and Materials Science Studies Utilizing the Microgravity-vibration Isolation Mount (MIM)

    NASA Technical Reports Server (NTRS)

    Herring, Rodney; Tryggvason, Bjarni; Duval, Walter

    1998-01-01

    Canada's Microgravity Sciences Program (MSP) is the smallest program of the ISS partners and so can participate in only a few, highly focused projects in order to make a scientific and technological impact. One focused project involves determining the effect of accelerations (g-jitter) on scientific measurements in a microgravity environment utilizing the Microgravity-vibration Isolation Mount (MIM). Many experiments share the common characteristic of having a fluid stage in their process. The quality of the experimental measurements have been expected to be affected by g-jitters which has lead the ISS program to include specifications to limit the level of acceleration allowed on a subset of experimental racks. From finite element analysis (FEM), the ISS structure will not be able to meet the acceleration specifications. Therefore, isolation systems are necessary. Fluid science results and materials science results show significant sensitivity to g-jitter. The work done to date should be viewed only as a first look at the issue of g-jitter sensitivity. The work should continue with high priority such that the international science community and the ISS program can address the requirement and settle on an agreed to overall approach as soon as possible.

  13. Microgravity vibration isolation: An optimal control law for the one-dimensional case

    NASA Technical Reports Server (NTRS)

    Hampton, Richard D.; Grodsinsky, Carlos M.; Allaire, Paul E.; Lewis, David W.; Knospe, Carl R.

    1991-01-01

    Certain experiments contemplated for space platforms must be isolated from the accelerations of the platform. An optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator (LQR) approach) along with constant feedforward gains. The quadratic cost function for this control algorithm effectively weights external accelerations of the platform disturbances by a factor proportional to (1/omega) exp 4. Low frequency accelerations are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feedforward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and velocities and the absolute accelerations of the experiment and space platform are available.

  14. Microgravity vibration isolation: An optimal control law for the one-dimensional case

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Grodsinsky, C. M.; Allaire, P. E.; Lewis, D. W.; Knospe, C. R.

    1991-01-01

    Certain experiments contemplated for space platforms must be isolated from the accelerations of the platforms. An optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator (LQR) approach) along with constant feedforward (preview) gains. The quadratic cost function for this control algorithm effectively weights external accelerations of the platform disturbances by a factor proportional to (1/omega)(exp 4). Low frequency accelerations (less than 50 Hz) are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feedforward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and velocities and the absolute accelerations of the experiment and space platform are available.

  15. Presentation to International Space University Students on g-LIMIT and STABLE-ATD Projects and Related Microgravity Vibration Isolation Topics

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean

    1998-01-01

    Vibration isolation is a necessity in the development of science in space and especially those experiments destined for operation on the International Space Station (ISS). The premise of microgravity scientific research is that in space, disturbances are minimized and experiments can be conducted in the absence of gravity. Although microgravity conditions exist in space, disturbances are still present in various forms and can be detrimental to the success of a microgravity experiment. Due to the plethora of disturbances and the various types that will occur on the space station, the microgravity community has elected to incorporate various means of isolating scientific payloads from these unwanted vibrations. Designing these vibration isolators is a crucial task to achieve true microgravity science. Since conventional methods of isolating payloads can achieve only limited isolation, new technologies are being developed to achieve the goal of designing a generic vibration isolation system. One such system being developed for the Microgravity Science Glovebox (MSG) is called g-LIMIT which stands for Glovebox Integrated Microgravity Isolation Technology. The g-LIMIT system is a miniaturized active vibration isolator for glovebox experiments. Although the system is initially developed for glovebox experiments, the g-LIMIT technology is designed to be upwardly scaleable to provide isolation for a broad range of users. The g-LIMIT system is scheduled to be flown on the UF-2 mission in August of the year 2000 and will be tested shortly thereafter. Once the system has been fully qualified, the hardware will become available for other researchers and will provide a platform upon which the goal of microgravity science can be achieved.

  16. Presentation to International Space University Students on g-LIMIT and STABLE-ATD Projects and Related Microgravity Vibration Isolation Topics

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean

    1998-01-01

    Vibration isolation is a necessity in the development of science in space and especially those experiments destined for operation on the International Space Station (ISS). The premise of microgravity scientific research is that in space, disturbances are minimized and experiments can be conducted in the absence of gravity. Although microgravity conditions exist in space, disturbances are still present in various forms and can be detrimental to the success of a microgravity experiment. Due to the plethora of disturbances and the various types that will occur on the space station, the microgravity community has elected to incorporate various means of isolating scientific payloads from these unwanted vibrations. Designing these vibration isolators is a crucial task to achieve true microgravity science. Since conventional methods of isolating payloads can achieve only limited isolation, new technologies are being developed to achieve the goal of designing a generic vibration isolation system. One such system being developed for the Microgravity Science Glovebox (MSG) is called g-LIMIT which stands for Glovebox Integrated Microgravity Isolation Technology. The g-LIMIT system is a miniaturized active vibration isolator for glovebox experiments. Although the system is initially developed for glovebox experiments, the g-LIMIT technology is designed to be upwardly scaleable to provide isolation for a broad range of users. The g-LIMIT system is scheduled to be flown on the UF-2 mission in August of the year 2000 and will be tested shortly thereafter. Once the system has been fully qualified, the hardware will become available for other researchers and will provide a platform upon which the goal of microgravity science can be achieved.

  17. A microgravity isolation mount

    NASA Technical Reports Server (NTRS)

    Jones, D. I.; Owens, A. R.; Owen, R. G.; Roberts, G.; Wyn-Roberts, D. W.; Robinson, A. A.

    1987-01-01

    The design and preliminary testing of a system for isolating microgravity sensitive payloads from spacecraft vibrational and impulsive disturbances is discussed. The Microgravity Isolation Mount (MGIM) concept consists of a platform which floats almost freely within a limited volume inside the spacecraft, but which is constrained to follow the spacecraft in the long term by means of very weak springs. The springs are realized magnetically and form part of a six degree of freedom active magnetic suspension system. The latter operates without any physical contact between the spacecraft and the platform itself. Power and data transfer is also performed by contactless means. Specifications are given for the expected level of input disturbances and the tolerable level of platform acceleration. The structural configuration of the mount is discussed and the design of the principal elements, i.e., actuators, sensors, control loops and power/data transfer devices are described. Finally, the construction of a hardware model that is being used to verify the predicted performance of the MGIM is described.

  18. Microgravity vibration isolation technology: Development to demonstration. Ph.D. Thesis - Case Western Reserve Univ.

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.

    1993-01-01

    The low gravity environment provided by space flight has afforded the science community a unique area for the study of fundamental and technological sciences. However, the dynamic environment observed on space shuttle flights and predicted for Space Station Freedom has complicated the analysis of prior 'microgravity' experiments and prompted concern for the viability of proposed space experiments requiring long term, low gravity environments. Thus, isolation systems capable of providing significant improvements to this random environment have been developed. This dissertation deals with the design constraints imposed by acceleration sensitive, microgravity experiment payloads in the unique environment of space. A theoretical background for the inertial feedback and feedforward isolation of a payload was developed giving the basis for two experimental active inertial isolation systems developed for the demonstration of these advanced active isolation techniques. A prototype six degree of freedom digital active isolation system was designed and developed for the ground based testing of an actively isolated payload in three horizontal degrees of freedom. A second functionally equivalent system was built for the multi-dimensional testing of an active inertial isolation system in a reduced gravity environment during low gravity aircraft trajectories. These multi-input multi-output control systems are discussed in detail with estimates on acceleration noise floor performance as well as the actual performance acceleration data. The attenuation performance is also given for both systems demonstrating the advantages between inertial and non-inertial control of a payload for both the ground base environment and the low gravity aircraft acceleration environment. A future goal for this area of research is to validate the technical approaches developed to the 0.01 Hz regime by demonstrating a functional active inertial feedforward/feedback isolation system during orbital flight

  19. Microgravity Vibration Control and Civil Applications

    NASA Technical Reports Server (NTRS)

    Whorton, Mark Stephen; Alhorn, Dean Carl

    1998-01-01

    Controlling vibration of structures is essential for both space structures as well as terrestrial structures. Due to the ambient acceleration levels anticipated for the International Space Station, active vibration isolation is required to provide a quiescent acceleration environment for many science experiments. An overview is given of systems developed and flight tested in orbit for microgravity vibration isolation. Technology developed for vibration control of flexible space structures may also be applied to control of terrestrial structures such as buildings and bridges subject to wind loading or earthquake excitation. Recent developments in modern robust control for flexible space structures are shown to provide good structural vibration control while maintaining robustness to model uncertainties. Results of a mixed H-2/H-infinity control design are provided for a benchmark problem in structural control for earthquake resistant buildings.

  20. Vibration isolation technology - An executive summary of systems development and demonstration. [for proposed microgravity experiments aboard STS and Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Grodsinsky, C. M.; Logsdon, K. A.; Lubomski, J. F.

    1993-01-01

    A program was organized to develop the enabling technologies needed for the use of Space Station Freedom as a viable microgravity experimental platform. One of these development programs was the Vibration Isolation Technology (VIT). This technology development program grew because of increased awareness that the acceleration disturbances present on the Space Transportation System (STS) orbiter can and are detrimental to many microgravity experiments proposed for STS, and in the future, Space Station Freedom (SSF). Overall technological organization are covered of the VIT program. Emphasis is given to the results from development and demonstration of enabling technologies to achieve the acceleration requirements perceived as those most likely needed for a variety of microgravity science experiments. In so doing, a brief summary of general theoretical approaches to controlling the acceleration environment of an isolated space based payload and the design and/or performance of two prototype six degree of freedom active magnetic isolation systems is presented.

  1. Advanced Technology for Isolating Payloads in Microgravity

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C.

    1997-01-01

    One presumption of scientific microgravity research is that while in space disturbances are minimized and experiments can be conducted in the absence of gravity. The problem with this assumption is that numerous disturbances actually occur in the space environment. Scientists must consider all disturbances when planning microgravity experiments. Although small disturbances, such as a human sneeze, do not cause most researchers on earth much concern, in space, these minuscule disturbances can be detrimental to the success or failure of an experiment. Therefore, a need exists to isolate experiments and provide a quiescent microgravity environment. The objective of microgravity isolation is to quantify all possible disturbances or vibrations and then attenuate the transmission of the disturbance to the experiment. Some well-defined vibration sources are: experiment operations, pumps, fans, antenna movements, ventilation systems and robotic manipulators. In some cases, it is possible to isolate the source using simple vibration dampers, shock absorbers and other isolation devices. The problem with simple isolation systems is that not all vibration frequencies are attenuated, especially frequencies less than 0.1 Hz. Therefore, some disturbances are actually emitted into the environment. Sometimes vibration sources are not well defined, or cannot be controlled. These include thermal "creak," random acoustic vibrations, aerodynamic drag, crew activities, and other similar disturbances. On some "microgravity missions," such as the United States Microgravity Laboratory (USML) and the International Microgravity Laboratory (IML) missions, the goal was to create extended quiescent times and limit crew activity during these times. This might be possible for short periods, but for extended durations it is impossible due to the nature of the space environment. On the International Space Station (ISS), vehicle attitude readjustments are required to keep the vehicle in a minimum

  2. An Indirect Mixed-Sensitivity Approach to Microgravity Vibration Isolation: The Exploitation of Kinematic Coupling In Frequency-weighting Design-Filter Selections

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Whorton, Mark S.

    2000-01-01

    Many space-science experiments need an active isolation system to provide them with the requisite microgravity environment. The isolation systems planned for use with the International Space Station have been appropriately modeled using relative position relative velocity, and acceleration states. In theory, frequency-weighting design filters can be applied to these state-space models, in order to develop optimal H2 or mixed-norm controllers with desired stability and performance characteristics. In practice, however, the kinematic coupling among the various states can lead, through the associated frequency-weighting-filters, to conflicting demands on the Riccati design "machinery." The results can be numerically ill-conditioned regulator and estimator Riccati equations and/or reduced intuition in the design process. In addition, kinematic coupling can result in a redundancy in the demands imposed by the frequency weights. Failure properly to account for this type of coupling can lead to an unnecessary increase in controller dimensionality and, in turn, controller complexity. This paper suggests a rational approach to the assignment of frequency-weighting design filters, in the presence of the kinematic coupling among states that exists in the microgravity vibration isolation problem.

  3. An Indirect Mixed-Sensitivity Approach to Microgravity Vibration Isolation: The Exploitation of Kinematic Coupling In Frequency-Weighting Design-Filter Selections

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Whorton, Mark S.

    2000-01-01

    Many space science experiments need an active isolation system to provide them with the requisite microgravity environment. The isolation systems planned for use with the International Space Station have been appropriately modeled using relative position, relative velocity, and acceleration states. In theory, frequency design filters can be applied to these state-space models, in order to develop optimal H, or mixed-norm controllers with desired stability- and performance characteristics. In practice. however, the kinematic coupling among the various states can lead, through the associated frequency-weighting-filters, to conflicting demands on the Riccati design "machinery." The results can be numerically ill-conditioned regulator and estimator Riccati equations and/or reduced intuition in the design process. In addition, kinematic coupling can result in a redundancy in the demands imposed by the frequency weights. Failure properly to account for this type of coupling can lead to an unnecessary increase in controller dimensionality and, in turn, controller complexity. This paper suggests a rational approach to the assignment of frequency weighting design filters, in the presence of the kinematic coupling among states that exists in the microgravity vibration isolation problem.

  4. Actively Controlled Magnetic Vibration-Isolation System

    NASA Technical Reports Server (NTRS)

    Grodsinky, Carlos M.; Logsdon, Kirk A.; Wbomski, Joseph F.; Brown, Gerald V.

    1993-01-01

    Prototype magnetic suspension system with active control isolates object from vibrations in all six degrees of freedom at frequencies as low as 0.01 Hz. Designed specifically to protect instruments aboard spacecraft by suppressing vibrations to microgravity levels; basic control approach used for such terrestrial uses as suppression of shocks and other vibrations in trucks and railroad cars.

  5. Microgravity isolation system design: A case study

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Knospe, C. R.; Allaire, P. E.; Grodsinsky, C. M.

    1994-01-01

    Many acceleration-sensitive, microgravity science experiments will require active vibration isolation from manned orbiters on which they will be mounted. The isolation problem, especially in the case of a tethered payload, is a complex three-dimensional one that is best suited to modern-control design methods. In this paper, extended H(sub 2) synthesis is used to design an active isolator (i.e., controller) for a realistic single-input-multiple-output (SIMO) microgravity vibration isolation problem. Complex mu-analysis methods are used to analyze the isolation system with respect to sensor, actuator, and umbilical uncertainties. The paper fully discusses the design process employed and the insights gained. This design case study provides a practical approach for isolation problems of greater complexity. Issues addressed include a physically intuitive state-space description of the system, disturbance and noise filters, filters for frequency weighting, and uncertainty models. The controlled system satisfies all the performance specifications and is robust with respect to model uncertainties.

  6. Microgravity isolation system design: A modern control synthesis framework

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Knospe, C. R.; Allaire, P. E.; Grodsinsky, C. M.

    1994-01-01

    Manned orbiters will require active vibration isolation for acceleration-sensitive microgravity science experiments. Since umbilicals are highly desirable or even indispensable for many experiments, and since their presence greatly affects the complexity of the isolation problem, they should be considered in control synthesis. In this paper a general framework is presented for applying extended H2 synthesis methods to the three-dimensional microgravity isolation problem. The methodology integrates control and state frequency weighting and input and output disturbance accommodation techniques into the basic H2 synthesis approach. The various system models needed for design and analysis are also presented. The paper concludes with a discussion of a general design philosophy for the microgravity vibration isolation problem.

  7. Microgravity isolation system design: A modern control synthesis framework

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Knospe, C. R.; Allaire, P. E.; Grodsinsky, C. M.

    1994-01-01

    Manned orbiters will require active vibration isolation for acceleration-sensitive microgravity science experiments. Since umbilicals are highly desirable or even indispensable for many experiments, and since their presence greatly affects the complexity of the isolation problem, they should be considered in control synthesis. A general framework is presented for applying extended H2 synthesis methods to the three-dimensional microgravity isolation problem. The methodology integrates control and state frequency weighting and input and output disturbance accommodation techniques into the basic H2 synthesis approach. The various system models needed for design and analysis are also presented. The paper concludes with a discussion of a general design philosophy for the microgravity vibration isolation problem.

  8. The Microgravity Isolation Mount (MGIM): A Columbus facility for improving the microgravity quality of payloads

    NASA Technical Reports Server (NTRS)

    Owen, R. G.; Jones, D. I.; Owens, A. R.; Roberts, G.; Hadfield, P.

    1992-01-01

    The Microgravity Isolation Mount (MGIM) is a facility for providing active vibration isolation for sensitive experiments on the Columbus Attached Laboratory and the Columbus Free-Flying Laboratory. The facility is designed to be accommodated in a standard Columbus rack, and it iterfaces with existing rack utility services. The design is based on a non-contact strategy, whereby the payload 'floats' inside the rack, and its position is controlled by a number of magnetic actuators. The main advantage of using this non-contact strategy is the improved microgravity quality available. The overall design of the facility and a description of its elements are given.

  9. The Microgravity Isolation Mount (MGIM): A Columbus facility for improving the microgravity quality of payloads

    NASA Technical Reports Server (NTRS)

    Owen, R. G.; Jones, D. I.; Owens, A. R.; Roberts, G.; Hadfield, P.

    1992-01-01

    The Microgravity Isolation Mount (MGIM) is a facility for providing active vibration isolation for sensitive experiments on the Columbus Attached Laboratory and the Columbus Free-Flying Laboratory. The facility is designed to be accommodated in a standard Columbus rack, and it iterfaces with existing rack utility services. The design is based on a non-contact strategy, whereby the payload 'floats' inside the rack, and its position is controlled by a number of magnetic actuators. The main advantage of using this non-contact strategy is the improved microgravity quality available. The overall design of the facility and a description of its elements are given.

  10. Vibration Isolation Technology (VIT) ATD Project

    NASA Technical Reports Server (NTRS)

    Lubomski, Joseph F.; Grodsinsky, Carlos M.; Logsdon, Kirk A.; Rohn, Douglas A.; Ramachandran, N.

    1994-01-01

    A fundamental advantage for performing material processing and fluid physics experiments in an orbital environment is the reduction in gravity driven phenomena. However, experience with manned spacecraft such as the Space Transportation System (STS) has demonstrated a dynamic acceleration environment far from being characterized as a 'microgravity' platform. Vibrations and transient disturbances from crew motions, thruster firings, rotating machinery etc. can have detrimental effects on many proposed microgravity science experiments. These same disturbances are also to be expected on the future space station. The Microgravity Science and Applications Division (MSAD) of the Office of Life and Microgravity Sciences and Applications (OLMSA), NASA Headquarters recognized the need for addressing this fundamental issue. As a result an Advanced Technology Development (ATD) project was initiated in the area of Vibration Isolation Technology (VIT) to develop methodologies for meeting future microgravity science needs. The objective of the Vibration Isolation Technology ATD project was to provide technology for the isolation of microgravity science experiments by developing methods to maintain a predictable, well defined, well characterized, and reproducible low-gravity environment, consistent with the needs of the microgravity science community. Included implicitly in this objective was the goal of advising the science community and hardware developers of the fundamental need to address the importance of maintaining, and how to maintain, a microgravity environment. This document will summarize the accomplishments of the VIT ATD which is now completed. There were three specific thrusts involved in the ATD effort. An analytical effort was performed at the Marshall Space Flight Center to define the sensitivity of selected experiments to residual and dynamic accelerations. This effort was redirected about half way through the ATD focusing specifically on the sensitivity of

  11. Microgravity isolation system design: A modern control analysis framework

    NASA Technical Reports Server (NTRS)

    Hampton, R. D.; Knospe, C. R.; Allaire, P. E.; Grodsinsky, C. M.

    1994-01-01

    Many acceleration-sensitive, microgravity science experiments will require active vibration isolation from the manned orbiters on which they will be mounted. The isolation problem, especially in the case of a tethered payload, is a complex three-dimensional one that is best suited to modern-control design methods. These methods, although more powerful than their classical counterparts, can nonetheless go only so far in meeting the design requirements for practical systems. Once a tentative controller design is available, it must still be evaluated to determine whether or not it is fully acceptable, and to compare it with other possible design candidates. Realistically, such evaluation will be an inherent part of a necessary iterative design process. In this paper, an approach is presented for applying complex mu-analysis methods to a closed-loop vibration isolation system (experiment plus controller). An analysis framework is presented for evaluating nominal stability, nominal performance, robust stability, and robust performance of active microgravity isolation systems, with emphasis on the effective use of mu-analysis methods.

  12. Fluid patterns and dynamics induced by vibrations in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Porter, Jeff; Tinao Perez-Miravete, Ignacio; Laverón-Simavilla, Ana

    Understanding the effects of vibrations is extremely important in microgravity environments where residual acceleration, or g-jitter, is easily generated by crew manoeuvring or machinery, and can have a significant impact on material processing systems and on-board experiments. Indeed, vibrations can dramatically affect fluid behaviour whether gravity is present or not, inducing instability in some cases while suppressing it in others. We will describe the results of investigations being conducted at the ESA affiliated Spanish User Support and Operations Centre (E-USOC) on the effect of vibrations on fluids interfaces, most notably with the forcing oriented parallel to the fluid surface. Pattern formation properties will be described in detail, and the importance of symmetry constraints and mean flows will be considered. Current exper-imental results are intriguing and have challenged existing assumptions in the field, particularly with regard to the parametric instability underlying subharmonic cross-waves. They suggest an intimate connection between Faraday waves, which are observed in vertically vibrated systems, and cross-waves, which are found in horizontally forced systems. Concurrent theoretical work, based on the analysis of reduced models, and on numerical simulations, will then be described. Finally, this research will be placed in a microgravity context and used to motivate the defini-tion of a proposed set of experiments on the International Space Station (ISS). The experiments would be in the large-aspect-ratio-limit, requiring relatively high frequency but low amplitude vibrations, where comparatively little microgravity research has been done. The interest of such a microgravity experiment will be discussed, with emphasis on fluid management and the potential of vibrations to act as a kind of artificial gravity by orienting surfaces (or density contours) perpendicular to the axis of vibration.

  13. Microgravity

    NASA Image and Video Library

    2004-04-15

    Protein isolated from hen egg-white and functions as a bacteriostatic enzyme by degrading bacterial cell walls. First enzyme ever characterized by protein crystallography. It is used as an excellent model system for better understanding parameters involved in microgravity experiments with data from laboratory experiments to study the equilibrium rate of hanging drop experiments in microgravity.

  14. The CFVib Experiment: Control of Fluids in Microgravity with Vibrations

    NASA Astrophysics Data System (ADS)

    Fernandez, J.; Sánchez, P. Salgado; Tinao, I.; Porter, J.; Ezquerro, J. M.

    2017-08-01

    The Control of Fluids in Microgravity with Vibrations (CFVib) experiment was selected for the 2016 Fly Your Thesis! programme as part of the 65th ESA Parabolic Flight Campaign. The aim of the project is to observe the potentially complex behaviour of vibrated liquids in weightless environments and to investigate the extent to which small-amplitude vibrations can be used to influence and control this behaviour. Piezoelectric materials are used to generate high-frequency vibrations to drive surface waves and large-scale reorientation of the interface. The theory of vibroequilibria, which treats the quasi-stationary surface configurations achieved by this reorientation, was used to predict interesting parameter regimes and interpret fluid behaviour. Here we describe the scientific motivation, objectives, and design of the experiment.

  15. Vibration isolation mounting system

    NASA Technical Reports Server (NTRS)

    Carter, Sam D. (Inventor); Bastin, Paul H. (Inventor)

    1995-01-01

    A system is disclosed for mounting a vibration producing device onto a spacecraft structure and also for isolating the vibration forces thereof from the structure. The system includes a mount on which the device is securely mounted and inner and outer rings. The rings and mount are concentrically positioned. The system includes a base (secured to the structure) and a set of links which are interconnected by a set of torsion bars which allow and resist relative rotational movement therebetween. The set of links are also rotatably connected to a set of brackets which are rigidly connected to the outer ring. Damped leaf springs interconnect the inner and outer rings and the mount allow relative translational movement therebetween in X and Y directions. The links, brackets and base are interconnected and configured so that they allow and resist translational movement of the device in the Z direction so that in combination with the springs they provide absorption of vibrational energy produced by the device in all three dimensions while providing rotational stiffness about all three axes to prevent undesired rotational motions.

  16. Microgravity

    NASA Image and Video Library

    1996-01-25

    Dan Carter and Charles Sisk center a Lysozyme Protein crystal grown aboard the USML-2 shuttle mission. Protein isolated from hen egg-white and functions as a bacteriostatic enzyme by degrading bacterial cell walls. First enzyme ever characterized by protein crystallography. It is used as an excellent model system for better understanding parameters involved in microgravity crystal growth experiments. The goal is to compare kinetic data from microgravity experiments with data from laboratory experiments to study the equilibrium.

  17. Microgravity Boiling Enhancement Using Vibration-Based Fluidic Technologies

    NASA Astrophysics Data System (ADS)

    Smith, Marc K.; Glezer, Ari; Heffington, Samuel N.

    2002-11-01

    Thermal management is an important subsystem in many devices and technologies used in a microgravity environment. The increased power requirements of new Space technologies and missions mean that the capacity and efficiency of thermal management systems must be improved. The current work addresses this need through the investigation and development of a direct liquid immersion heat transfer cell for microgravity applications. The device is based on boiling heat transfer enhanced by two fluidic technologies developed at Georgia Tech. The first of these fluidic technologies, called vibration-induced bubble ejection, is shown in Fig. 1. Here, an air bubble in water is held against a vibrating diaphragm by buoyancy. The vibrations at 440 Hz induce violent oscillations of the air/water interface that can result in small bubbles being ejected from the larger air bubble (Fig. 1a) and, simultaneously, the collapse of the air/water interface against the solid surface (Fig. 1b). Both effects would be useful during a heat transfer process. Bubble ejection would force vapor bubbles back into the cooler liquid so that they can condense. Interfacial collapse would tend to keep the hot surface wet thereby increasing liquid evaporation and heat transfer to the bulk liquid. Figure 2 shows the effect of vibrating the solid surface at 7.6 kHz. Here, small-scale capillary waves appear on the surface of the bubble near the attachment point on the solid surface (the grainy region). The vibration produces a net force on the bubble that pushes it away from the solid surface. As a result, the bubble detaches from the solid and is propelled into the bulk liquid. This force works against buoyancy and so it would be even more effective in a microgravity environment. The benefit of the force in a boiling process would be to push vapor bubbles off the solid surface, thus helping to keep the solid surface wet and increasing the heat transfer. The second fluidic technology to be employed in this

  18. Surface instabilities and reorientation induced by vibration in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier; Ezquerro Navarro, Jose Miguel

    2012-07-01

    The behavior of vibrated fluids and, in particular, the surface or interfacial instabilities that commonly arise in these systems have been the subject of continued experimental and theoretical attention since Faraday's seminal experiments in 1831. Both orientation and frequency are critical in determining the response of the fluid to excitation. Low frequencies are associated with sloshing while higher frequencies may generate Faraday waves or cross-waves, depending on whether the axis of vibration is perpendicular or parallel to the interface. In addition, high frequency vibrations are known to produce large scale reorientation of the fluid (vibroequilibria), an effect that becomes especially pronounced in the absence of gravity. We describe the results of investigations conducted at the ESA affiliated Spanish User Support and Operations Centre (E-USOC) on the effect of vibrations on fluid interfaces, particularly the interaction between Faraday waves, which arise in vertically vibrated systems, cross-waves, which are found in horizontally forced systems, and large scale reorientation (vibroequilibria). Ongoing ground experiments utilizing a dual-axis shaker configuration are described, including the effect on pattern formation of varying the two independent forcing frequencies, amplitudes, and phases. Theoretical results, based on the analysis of reduced models, and on numerical simulations, are then described and compared to experiment. Finally, the interest of a corresponding microgravity experiment is discussed and implications for fluid management strategies considered.

  19. Vibration isolation of superconducting magnets

    SciTech Connect

    Minas, C.; Herd, K.G.; Laskaris, E.T.

    1992-07-14

    This patent describes a vibration isolation system for a superconducting magnet having a first magnet and a thermal shield. It comprises: a cryocooler means having first and second stages and located substantially adjacent to the thermal shield; a cyrostat means located substantially adjacent the cryocooler means; and resilient vibration isolator means connected between the first magnet and the cryocooler means and also, between the cryocooler means and cyrostat means.

  20. Vibration Induced Phenomena in Granular Media in Microgravity

    NASA Astrophysics Data System (ADS)

    Opsomer, Eric; Noirhomme, Martial; Vandewalle, Nicolas

    2017-06-01

    In order to study the dynamical behavior and the handling properties of granular materials under microgravity conditions, ESA is developing the VIP-Gran instrument whose multiple functionalities allow for the study of Vibration Induced Phenomena in Granular media in low gravity. Here, we present an overview of VIP-Gran's evolution, from the original idea to the latest encouraging and fascinating results. At first, we give a description of the instrument and the different investigated topics. Then, we present numerical simulations that we performed in order to prepare our experiments and tackle fundamental questions concerning granular gases. Finally, we give an insight on the first experimental results from parabolic flight campaigns and confront them with preliminary works and theoretical models.

  1. Development of vibration isolation platform for low amplitude vibration

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Oen; Park, Geeyong; Han, Jae-Hung

    2014-03-01

    The performance of high precision payloads on board a satellite is extremely sensitive to vibration. Although vibration environment of a satellite on orbit is very gentle compared to the launch environment, even a low amplitude vibration disturbances generated by reaction wheel assembly, cryocoolers, etc may cause serious problems in performing tasks such as capturing high resolution images. The most commonly taken approach to protect sensitive payloads from performance degrading vibration is application of vibration isolator. In this paper, development of vibration isolation platform for low amplitude vibration is discussed. Firstly, single axis vibration isolator is developed by adapting three parameter model using bellows and viscous fluid. The isolation performance of the developed single axis isolator is evaluated by measuring force transmissibility. The measured transmissibility shows that both the low Q-factor (about 2) and the high roll-off rate (about -40 dB/dec) are achieved with the developed isolator. Then, six single axis isolators are combined to form Stewart platform in cubic configuration to provide multi-axis vibration isolation. The isolation performance of the developed multi-axis isolator is evaluated using a simple prototype reaction wheel model in which wheel imbalance is the major source of vibration. The transmitted force without vibration isolator is measured and compared with the transmitted force with vibration isolator. More than 20 dB reduction of the X and Y direction (radial direction of flywheel) disturbance is observed for rotating wheel speed of 100 Hz and higher.

  2. Microgravity

    NASA Image and Video Library

    2001-01-24

    The Protein Crystallization for Microgravity (DCAM) was developed at NASA's Marshall Space Flight Center. A droplet of solution with protein molecules dissolved in it is isolated in the center of a small well. In orbit, an elastomer seal is lifted so the solution can evaporate and be absorbed by a wick material. This raises the concentration of the solution, thus prompting protein molecules in the solution to form crystals. The principal investigator is Dr. Dan Carter of New Century Pharmaceuticals in Huntsville, AL.

  3. High performance rotational vibration isolator

    NASA Astrophysics Data System (ADS)

    Sunderland, Andrew; Blair, David G.; Ju, Li; Golden, Howard; Torres, Francis; Chen, Xu; Lockwood, Ray; Wolfgram, Peter

    2013-10-01

    We present a new rotational vibration isolator with an extremely low resonant frequency of 0.055 ± 0.002 Hz. The isolator consists of two concentric spheres separated by a layer of water and joined by very soft silicone springs. The isolator reduces rotation noise at all frequencies above its resonance which is very important for airborne mineral detection. We show that more than 40 dB of isolation is achieved in a helicopter survey for rotations at frequencies between 2 Hz and 20 Hz. Issues affecting performance such as translation to rotation coupling and temperature are discussed. The isolator contains almost no metal, making it particularly suitable for electromagnetic sensors.

  4. High performance rotational vibration isolator.

    PubMed

    Sunderland, Andrew; Blair, David G; Ju, Li; Golden, Howard; Torres, Francis; Chen, Xu; Lockwood, Ray; Wolfgram, Peter

    2013-10-01

    We present a new rotational vibration isolator with an extremely low resonant frequency of 0.055 ± 0.002 Hz. The isolator consists of two concentric spheres separated by a layer of water and joined by very soft silicone springs. The isolator reduces rotation noise at all frequencies above its resonance which is very important for airborne mineral detection. We show that more than 40 dB of isolation is achieved in a helicopter survey for rotations at frequencies between 2 Hz and 20 Hz. Issues affecting performance such as translation to rotation coupling and temperature are discussed. The isolator contains almost no metal, making it particularly suitable for electromagnetic sensors.

  5. Frequency Weighted H2 Control Design for the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT)

    NASA Technical Reports Server (NTRS)

    Calhoun, Philip C.; Hampton, R. David

    2004-01-01

    The acceleration environment on the International Space Station (ISS) exceeds the requirements of many microgravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) has been built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for microgravity science experiments. The g-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform, for mounting science payloads, from the nominal acceleration environment. The system utilizes payload-acceleration, relative-position, and relative-orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current commands to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. The present work documents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for frequency-weighted H2 norms. Comparison of performance and robustness to plant uncertainty for this control design approach is included in the discussion. System performance is demonstrated in the presence of plant modeling error.

  6. Seismic, shock, and vibration isolation 1991

    SciTech Connect

    Chung, H.H. )

    1991-01-01

    It covers a wide variety of topics, including shock and vibration isolation analysis methods, development of new isolation system, characterization of material properties of vibration isolation components, analytical/experimental methods, optimal isolation design, and isolation system design criteria and requirements. The structures considered included buildings, high-tech facilities, nuclear power plants, and pipe lines. The work reported here is representative of current research activities and contributed to the advancement of the state of the art in vibration isolation. THe editor hopes this volume will serve as a useful resource for research and design engineers and stimulate further interest in seismic, shock, and vibration isolation research.

  7. Microgravity

    NASA Image and Video Library

    2001-01-24

    An artist's concept of the Primary Atomic Clock Reference System (PARCS) plarned to fly on the International Space Station (ISS). PARCS will make even more accurate atomic time available to everyone, from physicists testing Einstein's Theory of Relativity, to hikers using the Global Positioning System to find their way. In ground-based atomic clocks, lasers are used to cool and nearly stop atoms of cesium whose vibrations are used as the time base. The microgravity of space will allow the atoms to be suspended in the clock rather than circulated in an atomic fountain, as required on Earth. PARCS is being developed by the Jet Propulsion Laboratory with principal investigators at the National Institutes of Standards and Technology and the University of Colorado, Boulder. See also No. 0103191

  8. Development and approach to low-frequency microgravity isolation systems

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.

    1990-01-01

    The low-gravity environment provided by space flight has afforded the science community a unique arena for the study of fundamental and technological sciences. However, the dynamic environment observed on space shuttle flights and predicted for Space Station Freedom has complicated the analysis of prior microgravity experiments and prompted concern for the viability of proposed space experiments requiring long-term, low-gravity environments. Thus, isolation systems capable of providing significant improvements to this random environment are being developed. The design constraints imposed by acceleration-sensitive, microgravity experiment payloads in the unique environment of space and a theoretical background for active isolation are discussed. A design is presented for a six-degree-of-freedom, active, inertial isolation system based on the baseline relative and inertial isolation techniques described.

  9. Vibration Isolation and Stabilization System for Spacecraft Exercise Treadmill Devices

    NASA Technical Reports Server (NTRS)

    Fialho, Ian; Tyer, Craig; Murphy, Bryan; Cotter, Paul; Thampi, Sreekumar

    2011-01-01

    A novel, passive system has been developed for isolating an exercise treadmill device from a spacecraft in a zero-G environment. The Treadmill 2 Vibration Isolation and Stabilization System (T2-VIS) mechanically isolates the exercise treadmill from the spacecraft/space station, thereby eliminating the detrimental effect that high impact loads generated during walking/running would have on the spacecraft structure and sensitive microgravity science experiments. This design uses a second stage spring, in series with the first stage, to achieve an order of magnitude higher exercise- frequency isolation than conventional systems have done, while maintaining desirable low-frequency stability performance. This novel isolator design, in conjunction with appropriately configured treadmill platform inertia properties, has been shown (by on-orbit zero-G testing onboard the International Space Station) to deliver exceedingly high levels of isolation/ stability performance.

  10. Torsional vibration isolator and method

    SciTech Connect

    Allen, C.A.; Durrett, V.D.

    1986-10-21

    This patent describes a multicylinder internal combustion engine having a rotatable crankshaft and a rotatable flywheel which together define an inertial system rotating about a predetermined axis of rotation. An improvement is described here which facilitates avoiding destructive effects on the crankshaft of stress induced by torsional vibration. The method comprises an elastomeric annulus coupling means operatively interposed between the crankshaft and flywheel for coupling the crankshaft and flywheel together for rotation of the flywheel with the crankshaft. The coupling means has a torsional spring rate of less than 20,000 in lb/radian effective to permit substantial angular displacement between the flywheel and the crankshaft for isolating the rotating inertia of the flywheel from the rotating inertia of the crankshaft after engine startup. The coupling means avoids dampening while preventing torsional vibration from being transferred between the flywheel and the crankshaft.

  11. Vibration Isolation of a Microphone.

    DTIC Science & Technology

    1985-09-01

    a. Microphone Replica A microphone replica identical in shape to the test microphone was machined from aluminum. A cutout was made on one side to...tion Research Program. 19. KEY WORDS (Continue on ,ererbe side if necesseary and identify by block number) vibration isolator, microphone, Space...34 ,.72_,IM=IN T S: -...S’L.’fMISS: READ ’SPL FOR ME..URED VOLTAGE RE.SF.E. READ XMISS’ FOR MEASURED TRANSMISEIBILITY . ’, ....... O ,IHED WERE WITHIN

  12. Microgravity Isolation Control System Design Via High-Order Sliding Mode Control

    NASA Technical Reports Server (NTRS)

    Shkolnikov, Ilya; Shtessel, Yuri; Whorton, Mark S.; Jackson, Mark

    2000-01-01

    Vibration isolation control system design for a microgravity experiment mount is considered. The controller design based on dynamic sliding manifold (DSM) technique is proposed to attenuate the accelerations transmitted to an isolated experiment mount either from a vibrating base or directly generated by the experiment, as well as to stabilize the internal dynamics of this nonminimum phase plant. An auxiliary DSM is employed to maintain the high-order sliding mode on the primary sliding manifold in the presence of uncertain actuator dynamics of second order. The primary DSM is designed for the closed-loop system in sliding mode to be a filter with given characteristics with respect to the input external disturbances.

  13. Microgravity

    NASA Image and Video Library

    2001-05-01

    Marshall Space Flight Center employees visited DuPont Manual High School in Louisville, Kentucky. NASA's Mini Drop Tower was used to demonstrate free fall and a presentation was given on microgravity and the science performed in a microgravity environment. The visit coincided with the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. Materials engineer Chris Cochrane explains the basics of microgravity research. This image is from a digital still camera; higher resolution is not available.

  14. Recent advances in micro-vibration isolation

    NASA Astrophysics Data System (ADS)

    Liu, Chunchuan; Jing, Xingjian; Daley, Steve; Li, Fengming

    2015-05-01

    Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the aerospace environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.

  15. Glovebox Integrated Microgravity Isolation Technology (g-LIMIT): A Linearized State-Space Model

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Calhoun, Philip C.; Whorton, Mark S.

    2001-01-01

    Vibration acceleration levels on large space platforms exceed the requirements of many space experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) is being built by the NASA Marshall Space Flight Center to attenuate these disturbances to acceptable levels. G-LIMIT uses Lorentz (voice-coil) magnetic actuators to levitate and isolate payloads at the individual experiment/sub-experiment (versus rack) level. Payload acceleration, relative position, and relative orientation measurements are fed to a state-space controller. The controller, in turn, determines the actuator Currents needed for effective experiment isolation. This paper presents the development of an algebraic, state-space model of g-LIMIT, in a form suitable for optimal controller design. The equations are first derived using Newton's Second Law directly, then simplified to a linear form for the purpose of controller design.

  16. Microgravity

    NASA Image and Video Library

    2001-05-01

    Marshall Space Flight Center employees visited DuPont Manual High School in Louisville, Kentucky. NASA's Mini Drop Tower was used to demonstrate free fall and a presentation was given on microgravity and the science performed in a microgravity environment. The visit coincided with the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. Materials engineer Chris Cochrane explains the operation of the mini-drop tower. This image is from a digital still camera; higher resolution is not available.

  17. Microgravity

    NASA Image and Video Library

    2001-05-01

    Marshall Space Flight Center employees visited DuPont Manual High School in Louisville, Kentucky. NASA's Mini Drop Tower was used to demonstrate free fall and a presentation was given on microgravity and the science performed in a microgravity environment. The visit coincided with the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. Students experiment with the mini-drop tower. This image is from a digital still camera; higher resolution is not available.

  18. Microgravity

    NASA Image and Video Library

    2001-05-01

    Marshall Space Flight Center employees visited DuPont Manual High School in Louisville, Kentucky. NASA's Mini Drop Tower was used to demonstrate free fall and a presentation was given on microgravity and the science performed in a microgravity environment. The visit coincided with the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. Students watch the playback of video from the mini-drop tower. This image is from a digital still camera; higher resolution is not available.

  19. Microgravity

    NASA Image and Video Library

    2001-04-25

    The arnual conference for the Educator Resource Center Network (ERCN) Coordinators was held at Glenn Research Center at Lewis Field in Cleveland, Ohio. The conference included participants from NASA's Educator Resource Centers located throughout the country. The Microgravity Science Division at Glenn sponsored a Microgravity Day for all the conference participants. Kathy Higgins of the National Center for Microgravity Research at GRC explains educational resources to teachers. This image is from a digital still camera; higher resolution is not available.

  20. Microgravity

    NASA Image and Video Library

    2000-04-14

    Jimmy Grisham of the Microgravity Program Plarning Integration Office at NASA/Marshall Space Flight Center, demonstrates the classroom-size Microgravity Drop Tower Demonstrator. The apparatus provides 1/6 second of microgravity for small experiments. A video camera helps teachers observe what happens inside the package. This demonstration was at the April 2000 conference of the National Council of Teachers of Mathematics (NCTM) in Chicago. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  1. Microgravity

    NASA Image and Video Library

    1995-09-12

    Two versions of (PCAM) Protein Crystallization Apparatus for Microgravity, (DCAM) Diffusion Controled Crystallization Apparatus is in the (STES) Single Locker Thermal Enclosure System. Principal Investigator was Dan Carter.

  2. Microgravity

    NASA Image and Video Library

    2000-07-29

    Dr. Richard DeLombard of NASA's Glenn Research Center, hands the relase line for the Microgravity Demonstrator to a visitor for her to start a short experiment showing the effects of microgravity on candle flames. Combustion physics will be a major line of investigation for NASA aboard the International Space Station (ISS). The Microgravity Demonstrator is frequently used at shows and schools to illustrate how phenomena change in microgravity. The exhibit was part of the NASA outreach activity at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI

  3. Microgravity

    NASA Image and Video Library

    1999-09-15

    A versatile experiment facility for the International Space Station moved closer to flight recently with delivery of the ground-test model to NASA's Marshall Flight Center. The Microgravity Science Glovebox Ground Unit was delivered to the Microgravity Development Laboratory will be used to test hardware and procedures for the flight model of the glovebox aboard the ISS's Laboratory Module, Destiny.

  4. Microgravity

    NASA Image and Video Library

    1999-09-13

    The first International Space Station experiment facility--the Microgravity Glovebox Ground Unit--has been delivered to Marshall Space Flight Center's Microgravity Development Laboratory. The glovebox is a facility that provides a sealed work area accessed by the crew in gloves. This glovebox will be used at the Marshall laboratory throughout the Space Station era.

  5. Microgravity

    NASA Image and Video Library

    2001-04-25

    The arnual conference for the Educator Resource Center Network (ERCN) Coordinators was held at Glenn Research Center at Lewis Field in Cleveland, Ohio. The conference included participants from NASA's Educator Resource Centers located throughout the country. The Microgravity Science Division at Glenn sponsored a Microgravity Day for all the conference participants. This image is from a digital still camera; higher resolution is not available.

  6. Microgravity

    NASA Image and Video Library

    2001-10-04

    Teachers, students, and parents listen as scientists explain what is different about the microgravity envirornment of space and why it is a valuable tool for research. This was part of the outreach session of the Pan Pacific Microgravity Conference on May 2, 2001, at the California Science Center.

  7. Two-Stage Passive Vibration Isolator

    NASA Technical Reports Server (NTRS)

    Goullioud, Renaud; Gursel, Yekta; Neville, Timothy; Bronowicki, Allen J.; Platus, David; MacDonald, Rhonda

    2008-01-01

    The design and testing of a structural system were implemented to hold the optics of the planned Space Interferometry Mission (SIM) at positions and orientations characterized by vibrational translation and rotation errors of no more than a few nanometers or a few milliarcseconds, respectively. Much of the effort was devoted to a test bed for verifying the predicted behavior of a vibration- isolation structural subsystem working together with an active control system for positioning and orienting the SIM optics. There was considerable emphasis on the vibration-isolation subsystem, which was passive and comprised two stages. The main sources of vibration were six reaction wheels in an assembly denoted the "backpack." The first vibration-isolation stage consisted of hexapod isolator mounts - one for each reaction wheel - characterized by a natural vibration frequency of 10 Hz. The second stage was a set of three beams, disposed between the backpack and the structure that held the SIM optics, that were flexured such that they transmitted only bending loads, with a natural vibrational frequency and damping of about 5 Hz and 4 percent, respectively. Preliminary test results were presented and characterized as demonstrating the effectiveness of the two-stage vibration-isolation design.

  8. Flywheel vibration isolation test using a variable-damping isolator

    NASA Astrophysics Data System (ADS)

    Oh, Hyun-Ung; Taniwaki, Shigemune; Kinjyo, Naofumi; Izawa, Katsuhiko

    2006-04-01

    This study demonstrates the isolation performance of a variable-damping isolator using a bio-metal fiber (BMF) valve to enhance the pointing performance of observation satellites by isolating disturbances induced by reaction wheel assemblies. Vibration isolation tests of the variable-damping isolator were performed using an air-floating wheel disturbance detector to investigate whether the isolator can actually isolate flywheel vibration. In this paper, we first present a recently developed variable-damping isolator with low power consumption, and a reaction wheel disturbance detector, fabricated in a previous study, which detects low-frequency disturbances. Next, we describe the effectiveness of the variable-damping isolator based on flywheel vibration isolation test results.

  9. Vibration isolation technology: An executive summary of systems development and demonstration

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos M.; Logsdon, Kirk A.; Lubomski, Joseph F.

    1993-01-01

    A program was organized to develop the enabling technologies needed for the use of Space Station Freedom as a viable microgravity experimental platform. One of these development programs was the Vibration Isolation Technology (VIT). This technology development program grew because of increased awareness that the acceleration disturbances present on the Space Transportation System (STS) orbiter can and are detrimental to many microgravity experiments proposed for STS, and in the future, Space Station Freedom (SSF). Overall technological organization are covered of the VIT program. Emphasis is given to the results from development and demonstration of enabling technologies to achieve the acceleration requirements perceived as those most likely needed for a variety of microgravity science experiments. In so doing, a brief summary of general theoretical approaches to controlling the acceleration environment of an isolated space based payload and the design and/or performance of two prototype six degree of freedom active magnetic isolation systems is presented.

  10. Mineral metabolism in isolated mouse long bones: Opposite effects of microgravity on mineralization and resorption

    NASA Technical Reports Server (NTRS)

    Veldhuijzen, Jean Paul; Vanloon, Jack J. W. A.

    1994-01-01

    An experiment using isolated skeletal tissues under microgravity, is reported. Fetal mouse long bones (metatarsals) were cultured for 4 days in the Biorack facility of Spacelab during the IML-1 (International Microgravity Laboratory) mission of the Space Shuttle. Overall growth was not affected, however glucose consumption was significantly reduced under microgravity. Mineralization of the diaphysis was also strongly reduced under microgravity as compared to the on-board 1 g group. In contrast, mineral resorption by osteoclasts was signficantly increased. These results indicate that these fetal mouse long bones are a sensitive and useful model to further study the cellular mechanisms involved in the changed mineral metabolism of skeletal tissues under microgravity.

  11. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Sandi Thompson of the National Center for Microgravity Research GRC makes a final adjustment to the drop package. This image is from a digital still camera; higher resolution is not available.

  12. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Here students from Sycamore High School in Cincinnati, Ohio, talk with Dr. Dennis Stocker, one of Glenn's lead microgravity scientists, about the uses of the drop tower. This image is from a digital still camera; higher resolution is not available.

  13. Microgravity

    NASA Image and Video Library

    1995-10-20

    Onboard Space Shuttle Columbia (STS-73) Payload Commander Kathryn Thornton works with the Drop Physics Module (DPM) in the United States Microgravity Laboratory 2 (USML-2) Spacelab Science Module cleaning the experiment chamber of the DPM.

  14. Microgravity

    NASA Image and Video Library

    1998-12-01

    International Flavors and Fragrances Inc., Dr. Braja Mookherjee with the Overnight Scentsation rose plant after its flight aboard NASA's shuttle mission STS-95 for experimentation on scent in microgravity.

  15. Microgravity

    NASA Image and Video Library

    1995-10-20

    Onboard Space Shuttle Columbia (STS-73) Payload Commander Kathryn Thornton and Commander Ken Bowersox discuss the Drop Physics Module (DPM) experiment in the United States Microgravity Laboratory 2 (USML-2) spacelab science module.

  16. Microgravity

    NASA Image and Video Library

    2001-01-24

    Dr. Cila Herman, G.W.C. Whiting School of Engineering, Johns Hopkins University, Baltimore. She is the principal investigator for the Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields.

  17. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Here Carol Hodanbosi of the National Center for Microgravity Research and Jose Carrion, a lab mechanic with AKAC, prepare a student experiment package (inside the silver-colored frame) inside the orange-colored drag shield that encloses all experiment hardware. This image is from a digital still camera; higher resolution is not available.

  18. Microgravity

    NASA Image and Video Library

    1995-10-20

    Astronaut Kathryn C. Thornton, payload commander, works at the Drop Physics Module (DPM) on the portside of the science module supporting the U.S. Microgravity Laboratory (USML-2). Astronaut Kerneth D. Bowersox, mission commander, looks on.

  19. Microgravity

    NASA Image and Video Library

    1995-10-20

    Onboard Space Shuttle Columbia (STS-73) Mission Specialists Catherine Cady Coleman works at the glovebox facility in support of the Protein Crystal Growth Glovebox (PCG-GBX) experiment in the United States Microgravity Laboratory 2 (USML-2) Spacelab science module.

  20. Microgravity

    NASA Image and Video Library

    1995-10-20

    Onboard Space Shuttle Columbia (STS-73) Payload Specialist Albert Sacco loads autoclaves using a power screwdriver into the Zeolite Crystal Growth (ZCG) experiment in the middeck for the United States Microgravity Laboratory 2 (USML-2) Spacelab mission.

  1. Microgravity

    NASA Image and Video Library

    1992-06-25

    Space Shuttle Columbia (STS-50) astronaut Bornie Dunbar wears protective goggles to assemble a zeolite sample cartridge for the Crystal Growth Furnace (CGF) in the United States Microgravity Laboratory-1 (USML-1) science module.

  2. Microgravity

    NASA Image and Video Library

    1992-04-24

    Ampoule view of the Vapor Crystal Growth System (VCGS) Furnace. Used on IML-1 International Microgravity Laboratory Spacelab 3. Prinicipal Investigator and Payload Specialist was Lodewijk van den Berg.

  3. Microgravity

    NASA Image and Video Library

    1992-04-24

    Overall view of the Vapor Crystal Growth System (VCGS) Furnace. Used on IML-1 International Microgravity Laboratory Spacelab 3. Principal Investigator and Payload Specialist was Lodewijk van den Berg.

  4. Microgravity

    NASA Image and Video Library

    1995-10-20

    Interface Configuration Experiment on the Second United States Microgravity Laboratory (USML-2). Over time the photos show a change in the shape of the interface between a liquid and a gas in a sealed, slightly asymmetrical container. Under the force of Earth's gravity, the interface would remain nearly flat, but in microgravity, the interface shape and location changes significantly in the container, resulting in major shifts of liquid arising from small asymmetries in the container shape.

  5. Microgravity

    NASA Image and Video Library

    2002-08-08

    Students discuss fine points of their final design for the Drop Tower experiment during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  6. Microgravity

    NASA Image and Video Library

    2002-08-07

    Students prepare to load fluids in their experiment apparatus during the Dropping In a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  7. Microgravity

    NASA Image and Video Library

    2002-08-07

    Students prepare their experiment apparatus for free-fall during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  8. Microgravity

    NASA Image and Video Library

    2002-08-08

    Students discuss fine points of their final design for the drop tower experiment during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  9. Microgravity

    NASA Image and Video Library

    2002-08-07

    Students prepare to load fluids in their experiment apparatus during the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  10. Microgravity

    NASA Image and Video Library

    2001-10-04

    Dr. Timothy G. Hammond of the Department of Internal Medicine, Nephrology Section, Tulane University Medical Center, New Orleans, LA, is one of NASA's principal investigators conducting research with the NASA Bioreactor project directed by Johrnson Space Center. Hammond's investigations include Production of 1-25- diOH D3 by Renal Epithelial Cells in Simulated Microgravity Culture and Differentiation of Cultured Normal Human Renal Epithelial Cells in Microgravity. Photo credit: Tulane University.

  11. Microgravity

    NASA Image and Video Library

    1997-11-15

    High school students observe the progress of the Isothermal Dendritic Growth Experiment (IDGE) during the U.S. Microgravity Payload-4 mission (STS-87, Nov. 19 - Dec. 5, 1997) at the IDGE Remote Operations Control Center (ROCC) at Rensselaer Polytechnic Institute (RPI) in Troy, NY. As part of the its outreach activity, the experiment team set up the center so students and the public could observe IDGE in progress and learn more about space and microgravity research. Photo credit: RPI

  12. Microgravity

    NASA Image and Video Library

    2002-08-08

    Students pause while waiting their turn at the 2.2-second Drop Tower during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  13. Microgravity

    NASA Image and Video Library

    2001-04-25

    The arnual conference for the Educator Resource Center Network (ERCN) Coordinators was held at Glenn Research Center at Lewis Field in Cleveland, Ohio. The conference included participants from NASA's Educator Resource Centers located throughout the country. The Microgravity Science Division at Glenn sponsored a Microgravity Day for all the conference participants. Dr. Wil Roberson and Marge Lehky prepare a demonstration with the mini-drop tower. This image is from a digital still camera; higher resolution is not available.

  14. Microgravity

    NASA Image and Video Library

    2002-08-07

    Student-designed and -built apparatus for the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  15. Microgravity

    NASA Image and Video Library

    2000-04-14

    Don Gillies, a materials scientist at NASA/Marshall Space Flight Center (MSFC), demonstrates the classroom-size Microgravity Drop Tower Demonstrator. The apparatus provides 1/6 second of microgravity for small experiments. A video camera helps teachers observe what happens inside the package. This demonstration was at the April 2000 conference of the National Council of Teachers of Mathematics (NCTM) in Chicago. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  16. The Microgravity Isolation Mount: A Linearized State-Space Model a la Newton and Kane

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Tryggvason, Bjarni V.; DeCarufel, Jean; Townsend, Miles A.; Wagar, William O.

    1999-01-01

    Vibration acceleration levels on large space platforms exceed the requirements of many space experiments. The Microgravity Vibration Isolation Mount (MIM) was built by the Canadian Space Agency to attenuate these disturbances to acceptable levels, and has been operational on the Russian Space Station Mir since May 1996. It has demonstrated good isolation performance and has supported several materials science experiments. The MIM uses Lorentz (voice-coil) magnetic actuators to levitate and isolate payloads at the individual experiment/sub-experiment (versus rack) level. Payload acceleration, relative position, and relative orientation (Euler-parameter) measurements are fed to a state-space controller. The controller, in turn, determines the actuator currents needed for effective experiment isolation. This paper presents the development of an algebraic, state-space model of the MIM, in a form suitable for optimal controller design. The equations are first derived using Newton's Second Law directly; then a second derivation (i.e., validation) of the same equations is provided, using Kane's approach.

  17. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. NASA and contractor personnel who conducted the DIME activity with the students. Shown (L-R) are: Eric Baumann (NASA, 2.2-second Drop Tower Facility manager), Daniel Dietrich (NASA) mentor for Sycamore High School team), Carol Hodanbosi (National Center for Microgravity Research; DIME staff), Richard DeLombard (NASA; DIME staff), Jose Carrion (GRC Akima, drop tower technician), Dennis Stocker (NASA; DIME staff), Peter Sunderland (NCMR, mentor for COSI Academy student team), Sandi Thompson (NSMR sabbatical teacher; DIME staff), Dan Woodard (MASA Microgravity Outreach Program Manager), Adam Malcolm (NASA co-op student; DIME staff), Carla Rosenberg (NCMR; DIME staff), and Twila Schneider (Infinity Technology; NASA Microgravity Research program contractor). This image is from a digital still camera; higher resolution is not available.

  18. Vibration Isolation, Suppression, Steering, and Pointing (VISSP)

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Rahman, Zahidul; Kedikian, Roland

    1996-01-01

    The design of a six degree of freedom flight vibration isolation suppression and steering (VISS) subsystem for a mid-wave infrared camera on the top of a spacecraft is presented. The development of a long stroke piezoelectric, redundant, compact, low stiffness and power efficient actuator is summarized. A subsystem that could be built and validated for flight within 15 months was investigated. The goals of the VISS are 20 dB vibration isolation above 2 Hz, 15 dB vibration suppression of disturbances at about 60 Hz and 120 Hz, and +/- 0.3 deg steering at 2 Hz and 4 Hz.

  19. A passive vibration-cancelling isolation mount

    NASA Technical Reports Server (NTRS)

    Sykes, Alan O.

    1987-01-01

    An analysis of an idealized passive vibration-cancelling two-terminal mount with one degree of freedom at each mechanical terminal isolating a nonrigid machine from a nonrigid foundation is presented. To evaluate a vibration-cancelling (VC) mount, its effectiveness as a function of frequency is compared with the effectiveness of both conventional and compound mounts isolating a rigid machine from a nonrigid foundation. The comparisons indicate that a carefully designed and manufactured VC mount should provide substantially greater vibration reduction at its cancellation frequency than either a conventional or compound mount having the same low frequency stiffness, i.e., stiffness at the natural frequency of the machine mount system.

  20. Vibration Isolation, Suppression, Steering, and Pointing (VISSP)

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Rahman, Zahidul; Kedikian, Roland

    1996-01-01

    The design of a six degree of freedom flight vibration isolation suppression and steering (VISS) subsystem for a mid-wave infrared camera on the top of a spacecraft is presented. The development of a long stroke piezoelectric, redundant, compact, low stiffness and power efficient actuator is summarized. A subsystem that could be built and validated for flight within 15 months was investigated. The goals of the VISS are 20 dB vibration isolation above 2 Hz, 15 dB vibration suppression of disturbances at about 60 Hz and 120 Hz, and +/- 0.3 deg steering at 2 Hz and 4 Hz.

  1. Optimal Control Design Using an H2 Method for the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT)

    NASA Technical Reports Server (NTRS)

    Calhoun, Phillip C.; Hampton, R. David; Whorton, Mark S.

    2001-01-01

    The acceleration environment on the International Space Station (ISS) will likely exceed the requirements of many micro-gravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) is being built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for micro-gravity science experiments. G-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform for mounting science payloads from the nominal acceleration environment. The system utilizes payload acceleration, relative position, and relative orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current command to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. This paper presents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for both frequency-weighted H(sub 2) and H(sub infinity) norms. Comparison of the performance and robustness to plant uncertainty for these two optimal control design approaches are included in the discussion.

  2. Optimal Control Design using an H(sub 2) Method for the Glovebox Integrated Microgravity Isolation Technology (G-Limit)

    NASA Technical Reports Server (NTRS)

    Calhoun, Philip C.; Hampton, R. David

    2002-01-01

    The acceleration environment on the International Space Station (ISS) will likely exceed the requirements of many micro-gravity experiments. The Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) is being built by the NASA Marshall Space Flight Center to attenuate the nominal acceleration environment and provide some isolation for microgravity science experiments. G-LIMIT uses Lorentz (voice-coil) magnetic actuators to isolate a platform for mounting science payloads from the nominal acceleration environment. The system utilizes payload acceleration, relative position, and relative orientation measurements in a feedback controller to accomplish the vibration isolation task. The controller provides current commands to six magnetic actuators, producing the required experiment isolation from the ISS acceleration environment. This paper presents the development of a candidate control law to meet the acceleration attenuation requirements for the g-LIMIT experiment platform. The controller design is developed using linear optimal control techniques for frequency-weighted H(sub 2) norms. Comparison of the performance and robustness to plant uncertainty for this control design approach is included in the discussion.

  3. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. This is the interior of the Sycamore High School (Cincinnati, Ohio) students' experiment to observe the flame spreading on a 100 percent cotton T-shirt under low-g. This image is from a digital still camera; higher resolution is not available.

  4. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Here Jose Carrion, a lab mechanic with AKAC, starts the orange-colored drag shield, and the experiment apparatus inside, on the hoist upward to the control station at the top of the drop tower. This image is from a digital still camera; higher resolution is not available.

  5. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Meredith Mendenhall of Sycamore High School, Cincinnati, Ohio, flips on a tape recorder in preparation for a drop. This image is from a digital still camera; higher resolution is not available.

  6. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Here, students from Sycamore High School in Cincinnati, Ohio, help a NASA technician prepare their experiment. This image is from a digital still camera; higher resolution is not available.

  7. Microgravity

    NASA Image and Video Library

    2004-04-15

    Researchers have found that as melted metals and alloys (combinations of metals) solidify, they can form with different arrangements of atoms, called microstructures. These microstructures depend on the shape of the interface (boundary) between the melted metal and the solid crystal it is forming. There are generally three shapes that the interface can take: planar, or flat; cellular, which looks like the cells of a beehive; and dendritic, which resembles tiny fir trees. Convection at this interface can affect the interface shape and hide the other phenomena (physical events). To reduce the effects of convection, researchers conduct experiments that examine and control conditions at the interface in microgravity. Microgravity also helps in the study of alloys composed of two metals that do not mix. On Earth, the liquid mixtures of these alloys settle into different layers due to gravity. In microgravity, the liquid metals do not settle, and a solid more uniform mixture of both metals can be formed.

  8. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Students from Sycamore High School in Cincinnati, Ohio (girls), and the COSI Academy, Columbus, Ohio (boys), participated. This image is from a digital still camera; higher resolution is not available.

  9. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Pictured are students from COSI Academy, Columbus, Ohio and their teacher. The other team was from Sycamore High School in Cincinnati, Ohio. This image is from a digital still camera; higher resolution is not available.

  10. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Here, students are briefed by NASA engineer Daniel Dietrich at the top of the drop tower. This image is from a digital still camera; higher resolution is not available.

  11. Microgravity

    NASA Image and Video Library

    1981-03-30

    Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

  12. Microgravity

    NASA Image and Video Library

    1999-08-03

    SPD representative Steve Lambing shows the PentaPure water purification unit to some EAA visitors. The Microgravity Research and the Space Product Development Programs joined with the Johnson Space Center (JSC) for a first time ever ISS/Microgravity Research space-focused exhibit at Oshkosh AirVenture'99 from July 28-August 3, 1999. The Space Product Development (SPD) display included the STS-95 ASTROCULTURE training hardware used by John Glenn and his crewmates, a PentaPure water purfication system, and a Ford engine block.

  13. Microgravity

    NASA Image and Video Library

    2002-08-07

    Members from all four teams were mixed into pairs to work on a Lego (TM) Challenge device to operate in the portable drop tower demonstrator (background). These two team members are about to try out their LEGO (TM) creation. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  14. Microgravity

    NASA Image and Video Library

    1997-01-01

    The Forced Flow Flame-Spreading Test was designed to study flame spreading over solid fuels when air is flowing at a low speed in the same direction as the flame spread. Previous research has shown that in low-speed concurrent airflows, some materials are more flammable in microgravity than earth. This image shows a 10-cm flame in microgravity that burns almost entirely blue on both sides of a thin sheet of paper. The glowing thermocouple in the lower half of the flame provides temperature measurements.

  15. Microgravity

    NASA Image and Video Library

    1998-05-01

    The Microgravity Science Glovebox is a facility for performing microgravity research in the areas of materials, combustion, fluids and biotechnology science. The facility occupies a full ISPR, consisting of: the ISPR rack and infrastructure for the rack, the glovebox core facility, data handling, rack stowage, outfitting equipment, and a video subsystem. MSG core facility provides the experiment developers a chamber with air filtering and recycling, up to two levels of containment, an airlock for transfer of payload equipment to/from the main volume, interface resources for the payload inside the core facility, resources inside the airlock, and storage drawers for MSG support equipment and consumables.

  16. Microgravity

    NASA Image and Video Library

    2004-04-15

    Fluid Physics is study of the motion of fluids and the effects of such motion. When a liquid is heated from the bottom to the boiling point in Earth's microgravity, small bubbles of heated gas form near the bottom of the container and are carried to the top of the liquid by gravity-driven convective flows. In the same setup in microgravity, the lack of convection and buoyancy allows the heated gas bubbles to grow larger and remain attached to the container's bottom for a significantly longer period.

  17. Microgravity

    NASA Image and Video Library

    2002-08-07

    A student assembles a Lego (TM) Challenge device designed to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  18. Microgravity

    NASA Image and Video Library

    2002-08-07

    Two students show the Lego (TM) Challenge device they designed and built to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  19. Microgravity

    NASA Image and Video Library

    2002-08-07

    A NASA test conductor at the top of the 2.2-second Drop Tower monitors a student lecture at a lower level. This was part of the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  20. Microgravity

    NASA Image and Video Library

    2002-08-07

    Students watch a test run on their experiment before the actual drop. They designed and built their apparatus to fit within a NASA-provided drop structure. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  1. Microgravity

    NASA Image and Video Library

    2000-07-29

    Paul Luz (right), an aerospace flight systems engineer at NASA's Marshall Space Flight Center (MSFC), takes a question from a visitor as they discuss microgravity research at AirVenture 2000. Part of the NASA exhibits included demonstrations of knowledge gained from microgravity research aboard the Space Shuttle. These include liquid metal (liquid metal demonstrator is three plastic drop tubes at center) and dendritic growth (in front of Luz), both leading to improvements in processes of Earth. The exhibit was part of the NASA outreach activity at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  2. Microgravity

    NASA Image and Video Library

    2002-08-30

    The Microgravity Science Glovebox Ground Unit, delivered to the Marshall Space Flight Center on August 30, 2002, will be used at Marshall's Microgravity Development Laboratory to test experiment hardware before it is installed in the flight glovebox aboard the International Space Station (ISS) U.S. Laboratory Module, Destiny. The glovebox is a sealed container with built in gloves on its sides and fronts that enables astronauts to work safely with experiments that involve fluids, flames, particles, and fumes that need to be safely contained.

  3. Microgravity

    NASA Image and Video Library

    2002-08-30

    This excellent shot of Marshall Space Flight Center's (MSFC's) Mark Whorton, testing experiment hardware in the Microgravity Science Glovebox Ground Unit delivered to MSFC on August 30, 2002, reveals a close look at the components inside of the Glovebox. The unit is being used at Marshall's Microgravity Development Laboratory to test experiment hardware before it is installed in the flight Glovebox aboard the International Space Station (ISS) U.S. Laboratory Module, Destiny. The glovebox is a sealed container with built in gloves on its sides and fronts that enables astronauts to work safely with experiments that involve fluids, flames, particles, and fumes that need to be safely contained.

  4. Microgravity

    NASA Image and Video Library

    2002-08-07

    A Bay High School team member prepares the oil and water samples for their next drop operation as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  5. Microgravity

    NASA Image and Video Library

    2001-04-25

    The arnual conference for the Educator Resource Center Network (ERCN) Coordinators was held at Glenn Research Center at Lewis Field in Cleveland, Ohio. The conference included participants from NASA's Educator Resource Centers located throughout the country. The Microgravity Science Division at Glenn sponsored a Microgravity Day for all the conference participants. Twila Schneider of Infinity Technology, a NASA contractor, explains the basics of building a glovebox mockup from a copier paper box. This image is from a digital still camera; higher resolution is not available.

  6. Microgravity

    NASA Image and Video Library

    2002-08-07

    Test tubes to hold different types of fluids while in free-fall were among the student-designed items for the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  7. Microgravity

    NASA Image and Video Library

    2002-08-07

    Students from the four teams pose in front of he NASA Glenn Administration Building alongside the NASA Glenn Time Capsule. The students participated in the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  8. Microgravity

    NASA Image and Video Library

    2002-08-08

    In addition to drop tower activities, students assembled a plastic pipe structure underwater in a SCUBA exercise similar to training astronauts receive at NASA Johnson Space Center. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  9. Microgravity

    NASA Image and Video Library

    2000-03-15

    Cadmium sulfide -- a semiconductor material -- can be grown in nanoclusters. Small molecules of cadmium sulfide, shown here, can be prepared by traditional chemical methods. However, if larger, more uniform nanoparticles of cadmium sulfide could be fabricated, they may be used to improve electronic devices such as light emitting diodes and diode lasers. Using a NASA grant, Dr. Jimmy Mays of the University of Alabama at Birmingham is studying whether microgravity will enhance the size and shape of a nanoparticle. This experiment is managed by the Microgravity Research Program Office at NASA's Marshall Spce Flight Center in Huntsville, AL. Photo credit: NASA/Marshall Space Flight Center

  10. Acute exposure to microgravity does not influence the H-reflex with or without whole body vibration and does not cause vibration-specific changes in muscular activity.

    PubMed

    Kramer, Andreas; Gollhofer, Albert; Ritzmann, Ramona

    2013-08-01

    Many potential countermeasures for muscle and bone loss caused by exposure to microgravity require an uncompromised stretch reflex system. This is especially true for whole body vibration (WBV), as the main source of the neuromuscular activity during WBV has been attributed to stretch reflexes. A priori, it cannot be assumed that reflexes and Ia afferent transmission in particular have the same characteristics in microgravity as in normal gravity (NG). Therefore, the purpose of the study was to compare Ia afferent transmission in microgravity and NG and to assess how microgravity affects muscle activity during WBV. In 14 participants, electromyographic activity of four leg muscles as well as Hoffmann-reflexes were recorded during NG and microgravity induced by parabolic flights. The size of the Hoffmann-reflex was reduced during WBV, but did not differ during acute exposure to microgravity compared to NG. The influence of the gravity conditions on the electromyographic activity did not change depending on the vibration condition. As far as the electromyographic activity of the recorded leg muscles is concerned, the effect of WBV is the same in microgravity as in NG. Moreover, Ia afferent transmission does not seem to be affected by acute exposure to microgravity when subjects are loaded with body weight and postural sway is minimized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Active vibration isolation by adaptive proportional control

    NASA Astrophysics Data System (ADS)

    Liu, Yun-Hui; Wu, Wei-Hao; Chu, Chih-Liang

    2013-01-01

    An active vibration isolation system that applies proportional controller incorporated with an adaptive filter to reduce the transmission of base excitations to a precision instrument is proposed in this work. The absolute vibration velocity signal acquired from an accelerator and being processed through an integrator is input to the controller as a feedback signal, and the controller output signal drives the voice coil actuator to produce a sky-hook damper force. In practice, the phase response of integrator at low frequency such as 2~5 Hz deviate from the 90 degree which is the exact phase difference between the vibration velocity and acceleration. Therefore, an adaptive filter is used to compensate the phase error in this paper. An analysis of this active vibration isolation system is presented, and model predictions are compared to experimental results. The results show that the proposed method significantly reduces transmissibility at resonance without the penalty of increased transmissibility at higher frequencies.

  12. Microgravity

    NASA Image and Video Library

    1992-10-22

    Space Shuttle Endeavour (STS-47) onboard photo of Astronaut N. Jan Davis at work at the Continuous Heating Furnace (CHF) in the Spacelab-J Science Module. Spacelab-J is a combined National Space Development Agency of Japan (NASDA) and NASA mission. The objectives included life sciences, microgravity and technology research.

  13. Microgravity

    NASA Image and Video Library

    1992-10-22

    Space Shuttle Endeavour (STS-47) onboard photo of Astronaut Mae Jemison working in Spacelab-J module. Spacelab-J is a combined National Space Development Agency of Japan (NASDA) and NASA mission. The objectives included life sciences, microgravity and technology research.

  14. Microgravity

    NASA Image and Video Library

    1999-01-01

    Gerard M. Faeth, University of Michigan, principal investigator in combustion science experiments, including Flow/Soot-Formation in Nonbuoyant Laminar Diffusion Flames, investigation of Laminar Jet Diffusion Flames in Microgravity: A Paradigm for Soot Processes in Turbulent Flames, and Soot Processes in Freely-Propagating Laminar Premixed Flames.

  15. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. Dendrite irritator control for the EDSE in the Microgravity Development Lab (MDL).

  16. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. NASA and contractor personnel who conducted the DIME activity with the students. Shown (L-R) are: Daniel Dietrich (NASA) mentor for Sycamore High School team), Carol Hodanbosi (National Center for Microgravity Research; DIME staff), Jose Carrion (GRC Akima, drop tower technician), Dennis Stocker (NASA; DIME staff), Richard DeLombard (NASA; DIME staff), Sandi Thompson (NSMR sabbatical teacher; DIME staff), Peter Sunderland (NCMR, mentor for COSI Academy student team), Adam Malcolm (NASA co-op student; DIME staff). This image is from a digital still camera; higher resolution is not available.

  17. Microgravity

    NASA Image and Video Library

    1997-03-11

    The Microgravity Science Glovebox (MSG) is being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  18. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows the interior reach in the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  19. Microgravity

    NASA Image and Video Library

    2001-05-31

    The Microgravity Science Glovebox is being developed by the European Space Agency and NASA to provide a large working volume for hands-on experiments aboard the International Space Station. Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center. (Credit: NASA/Marshall)

  20. Microgravity

    NASA Image and Video Library

    1992-09-12

    Space Shuttle Endeavour (STS-47) onboard photo of Astronaut Jan Davis inside the Spacelab-J module. Spacelab-J is a combined National Space Development Agency of Japan (NASDA) and NASA mission. The objectives included life sciences, microgravity and technology research.

  1. Microgravity

    NASA Image and Video Library

    1995-10-20

    Astronaut Catherine G. Coleman, mission specialist, checks out an Astroculture sample on the mid-deck of the Earth-orbiting Space Shuttle Columbia. Coleman was joined by four other NASA astronauts and two guest researchers for 16 full days of in-space research in support of the United States Microgravity Laboratory (USML-2) mission.

  2. Microgravity

    NASA Image and Video Library

    1998-01-01

    Dr. Daniel Carter, president of New Century Pharmaceuticals in Huntsville, Al, is one of three principal investigators in NASA's microgravity protein crystal growth program. Dr. Carter's experties is in albumins. Albumins are proteins in the bloodstream that transport materials, drugs, nutrients, and wastes. Photo credit: NASA/Marshall Space Flight Center

  3. Microgravity

    NASA Image and Video Library

    2004-04-15

    The shuttle is a reusable launch vehicle that can maintain a consistent orbit and provide up to 17 days of high-quality microgravity conditions. The shuttle, which can accomodate a wide range of experiment apparatus, provides a laboratory environment in which scientists can conduct long-term investigations.

  4. Microgravity

    NASA Image and Video Library

    1998-04-01

    During the STS-90 shuttle flight in April 1998, cultured renal cortical cells revealed new information about genes. Timothy Hammond, an investigator in NASA's microgravity biotechnology program was interested in culturing kidney tissue to study the expression of proteins useful in the treatment of kidney diseases. Protein expression is linked to the level of differentiation of the kidney cells, and Hammond had difficulty maintaining differentiated cells in vitro. Intrigued by the improvement in cell differentiation that he observed in rat renal cells cultured in NASA's rotating wall vessel (a bioreactor that simulates some aspects of microgravity) and during an experiment performed on the Russian Space Station Mir, Hammond decided to sleuth out which genes were responsible for controlling differentiation of kidney cells. To do this, he compared the gene activity of human renal cells in a variety of gravitational environments, including the microgravity of the space shuttle and the high-gravity environment of a centrifuge. Hammond found that 1,632 genes out of 10,000 analyzed changed their activity level in microgravity, more than in any of the other environments. These results have important implications for kidney research as well as for understanding the basic mechanism for controlling cell differentiation.

  5. Microgravity

    NASA Image and Video Library

    1997-11-19

    Onboard Space Shuttle Columbia (STS-87) mid-deck, Leonid Kadenyuk, Ukrainian payload specialist, works with the Brassica rapa plants being grown for the Collaborative Ukrainian Experiment (CUE). Kadenyuk joined five astronauts for 16-days in Earth-orbit in support of the United States Microgravity Payload 4 (USMP-4) mission.

  6. Microgravity

    NASA Image and Video Library

    1994-03-04

    Onboard Space Shuttle Columbia (STS-62) Mission specialist Charles D. (Sam) Gemar works with the Middeck 0-Gravity Dynamics Experiment (MODE). The reusable test facility is designed to study the nonlinear, gravity-dependent behavior of liquids and skewed space structures in the microgravity environment.

  7. Microgravity

    NASA Image and Video Library

    2004-04-15

    Manual activation of 8 FPAs in an earlier version of the Group Activation Pack. The Fluids Processing Apparatus is essentially a microgravity test tube that allows a variety of complex investigations to be performed in space. Developed by BioServe Space Technologies, a NASA Commercial Space Center. Flown on STS-95.

  8. Microgravity

    NASA Image and Video Library

    2000-11-03

    On the Space Shuttle Orbiter Atlantis' middeck, Astronaut Donald R. McMonagle, mission commander, works with the Heat Pipe Performance (HPP-2) experiment during STS-66 mission. HPP-2 was flown to investigate the thermal performance and fluid dynamics of heat pipes operating with asymmetric and multiple heating zones under microgravity condition.

  9. Microgravity

    NASA Image and Video Library

    1998-09-30

    The Electrostatic Levitator (ESL) Facility established at Marshall Space Flight Center (MSFC) supports NASA's Microgravity Materials Science Research Program. NASA materials science investigations include ground-based, flight definition and flight projects. Flight definition projects, with demanding science concept review schedules, receive highest priority for scheduling experiment time in the Electrostatic Levitator (ESL) Facility.

  10. Microgravity

    NASA Image and Video Library

    1996-06-20

    Onboard Space Shuttle Columbia (STS-78) Mission Specialist Richard M. Lirnehan works out in the Life and Microgravity Spacelab (LMS-1) Science Module. With an almost 17-day mission away from Earth's gravity, crew members maintained an exercise regimen above and beyond their assigned LMS-1 duty assignments.

  11. Microgravity

    NASA Image and Video Library

    2004-04-15

    BioServe researcher Dr. Yi Li first flew plant experiments on board STS-63. Li discovered that exposure to microgravity increased a particular hormone concentration in plants. Since that time, Li has been able to manipulate this phenomenon and grow fruits, such as tomatoes, that overproduce the hormone, and these plants bear larger seedless fruit in the absence of pollination.

  12. Microgravity

    NASA Image and Video Library

    2001-01-24

    Exterior view of Combustion Module-2 with callouts to identify key sections. The original CM flew on the Microgravity Sciences Lab-1 and 1R in 1997. It has been refurbished and placed in new racks for flight on the STS-107 Research 1 mission in 2001. Glenn Research in Cleveland, OH, manages the project.

  13. Active Inertial Vibration Isolators And Dampers

    NASA Technical Reports Server (NTRS)

    Laughlin, Darren; Blackburn, John; Smith, Dennis

    1994-01-01

    Report describes development of active inertial vibration isolators and dampers in which actuators electromagnet coils moving linearly within permanent magnetic fields in housings, somewhat as though massive, low-frequency voice coils in loudspeakers. Discusses principle of operation, electrical and mechanical considerations in design of actuators, characteristics of accelerometers, and frequency responses of control systems. Describes design and performance of one- and three-degree-of-freedom vibration-suppressing system based on concept.

  14. Vibration isolation for broadband gravitational wave antennas

    SciTech Connect

    Saulson, P.R.

    1984-08-01

    We discuss an active vibration isolation system which is a prototype of an isolation system for an interferometric gravitational wave antenna. Particular attention is paid to factors which limit the isolation which can be achieved. We were able to reduce the effective resonant frequency of the test mass to 0.04 Hz. Between 3 and 8 Hz, this was sufficient to bring the motion of the test mass within a factor of 2 of its Brownian motion amplitude.

  15. From flow and particle transport modeling to vibration isolation

    NASA Astrophysics Data System (ADS)

    Ellison, Joseph Fabian

    2001-08-01

    This thesis is composed of two parts. Part I is devoted to the analysis of particle transport and deposition. In this part, flow and particle transport and deposition in a furnace and under microgravity conditions are analyzed. In the first study of Part I, fluid flow, combustion, heat and mass transfer involved in a methane/air furnace were studied. The purpose of this study was to investigate variations in the flow field and thermal conditions in the furnace and to develop methods for improving its efficiency. The analysis of the combustor model was performed using an unstructured grid model developed with the Gambit grid generator of FLUENT version 5. In the second study of Part I, particle dispersion in a liquid filled box under orbital g-jitter excitation is analyzed. The study investigated particle motion experiments that were performed aboard the orbiting shuttle. The experiments have provided confusing data as to the nature of particle dispersion in the orbital environment. To obtain a better understanding of the dynamics involved, a series of numerical simulations are performed to study the dispersion of suspended particles subject to g-jitter excitations. Part II of the thesis is devoted to the analysis of vibration and vibration isolation problems. Following along the lines of vibration effecting system performance, a study of vibration isolation used to protect avionics equipment from adverse aircraft vibration environments was conducted. Passive isolation is the simplest means to achieve this goal. The system used here consisted of a circular steel ring with a lump mass on top and exposed to base excitation. Sinusoidal and filtered zero-mean Gaussian white noise were used to excite the structure and the acceleration response spectra at the top of the ring were computed. An experiment was performed to identify the natural frequencies and modal damping of the circular ring. The polished homogeneity measurement of large optics mounted in a vertical ring

  16. Microgravity

    NASA Image and Video Library

    2001-01-24

    Dr. Alexander Chernov, of the Universities Space Research Association (USRA) and based at Marshall Space Flight Center, is investigating why protein crystals grown in space are, in about 20 percent of cases, better-ordered than those grown on the ground. They are testing the idea that the amount of impurities trapped by space-grown crystals may be different than the amount trapped by crystals grown on Earth because convection is negligible in microgravity. The concentrations or impurities in many space-grown crystals turned out to be several times lower than that in the terrestrial ones, sometimes below the detection limit. The ground-based experiment also showed that the amount of impurities per unit volume of the crystals was usually higher than the amount per unit volume of the solution. This means that a growing crystal actually purifies the solution in its immediate vicinity. Here, an impurity depletion zone is created around apoferritin crystals grown in gel, imitating microgravity conditions.

  17. Microgravity

    NASA Image and Video Library

    2000-12-15

    Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Bioactive glass particles (left) with a microporous surface (right) are widely accepted as a synthetic material for periodontal procedures. Using the particles to grow three-dimensional tissue cultures may one day result in developing an improved, more rugged bone tissue that may be used to correct skeletal disorders and bone defects. The work is sponsored by NASA's Office of Biological and Physical Research.

  18. Microgravity

    NASA Image and Video Library

    2001-05-02

    John Henson (grade 12) and Suzi Bryce (grade 10) from DuPont Manual High School in Louisville, Kentucky, conduct a drop with NASA's Microgravity Demonstrator. A camera and a TV/VCR unit let students play back recordings of how different physical devices behave differently during freefall as compared to 1-g. The activity was part of the education outreach segment of the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. This image is from a digital still camera; higher resolution is not available.

  19. Microgravity

    NASA Image and Video Library

    2001-05-02

    John Henson (grade 12) and Suzi Bryce (grade 10) conducted the drop from DuPont Manual High School in Louisville, Kentucky, conduct a drop with NASA's Microgravity Demonstrator. A camera and a TV/VCR unit let students play back recordings of how different physical devices behave differently during freefall as compared to 1-g. The activity was part of the education outreach segment of the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. This image is from a digital still camera; higher resolution is not available.

  20. Microgravity

    NASA Image and Video Library

    2000-01-31

    The Fluids and Combustion Facility (FCF) is a modular, multi-user facility to accommodate microgravity science experiments on board Destiny, the U.S. Laboratory Module for the International Space Station (ISS). The FCF will be a permanet facility aboard the ISS, and will be capable of accommodating up to ten science investigations per year. It will support the NASA Science and Technology Research Plans for the International Space Station (ISS) which require sustained systematic research of the effects of reduced gravity in the areas of fluid physics and combustion science. From left to right are the Combustion Integrated Rack, the Shared Rack, and the Fluids Integrated Rack. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo Credit: NASA/Marshall Space Flight Center)

  1. Microgravity

    NASA Image and Video Library

    2001-01-24

    Advanced finite element models are used to study three-dimensional, time-dependent flow and segregation in crystal growth systems. In this image of a prototypical model for melt and crystal growth, pathlines at one instant in time are shown for the flow of heated liquid silicon in a cylindrical container. The container is subjected to g-jitter disturbances along the vertical axis. A transverse magnetic field is applied to control them. Such computations are extremely powerful for understanding melt growth in microgravity where g-jitter drives buoyant flows. The simulation is part of the Theoretical Analysis of 3D, Transient Convection and Segregation in Microgravity Bridgman Crystal Growth investigation by Dr. Jeffrey J. Derby of the University of Mirnesota, Minneapolis.

  2. Microgravity

    NASA Image and Video Library

    1992-06-25

    Zeolites are crystalline aluminosilicates that have complex framework structures. However, there are several features of zeolite crystals that make unequivocal structure determinations difficult. The acquisition of reliable structural information on zeolites is greatly facilitated by the availability of high-quality specimens. For structure determinations by conventional diffraction techniques, large single-crystal specimens are essential. Alternatively, structural determinations by powder profile refinement methods relax the constraints on crystal size, but still require materials with a high degree of crystalline perfection. Studies conducted at CAMMP (Center for Advanced Microgravity Materials Processing) have demonstrated that microgravity processing can produce larger crystal sizes and fewer structural defects relative to terrestrial crystal growth. Principal Investigator: Dr. Albert Sacco

  3. Microgravity

    NASA Image and Video Library

    1994-02-03

    The objective of this facility is to investigate the potential of space grown semiconductor materials by the vapor transport technique and develop powdered metal and ceramic sintering techniques in microgravity. The materials processed or developed in the SEF have potential application for improving infrared detectors, nuclear particle detectors, photovoltaic cells, bearing cutting tools, electrical brushes and catalysts for chemical production. Flown on STS-60 Commercial Center: Consortium for Materials Development in Space - University of Alabama Huntsville (UAH)

  4. Microgravity

    NASA Image and Video Library

    2004-04-15

    These are images of CGEL-2 samples taken during STS-95. They show binary colloidal suspensions that have formed ordered crystalline structures in microgravity. In sample 5, there are more particles therefore, many, many crystallites (small crystals) form. In sample 6, there are less particles therefore, the particles are far apart and few, much larger crystallites form. The white object in the right corner of sample 5 is the stir bar used to mix the sample at the begirning of the mission.

  5. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several quiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. George Myers, controls engineer, monitors the thermal environment of a ground test for the EDSE located in the Microgravity Development Laboratory (MDL).

  6. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. This image shows the overview for the EDSE in the Microgravity Development Lab (MDL).

  7. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. Video and power rack for the EDSE in the Microgravity Development Lab (MDL).

  8. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. This image shows the isothermal bath and video system for the EDSE in the Microgravity Development Lab (MDL).

  9. Microgravity

    NASA Image and Video Library

    2001-10-04

    Professor Gerard M. Faeth, Department of Aerospace Engineering, University of Michigan, Arn Arbor, MI, is a principal investigator in NASA combustion science directed by Glenn Research Center. His projects include: Soot Processes in Freely-Propagating Laminar Premixed Flames; Investigation of Laminar Jet Diffusion Flames in Microgravity: A Paradigm for Soot Processes in Turbulent Flames (scheduled to fly on the STS-107 mission); and Flow/Soot- Formation in Nonbuoyant Laminar Diffusion Flames.

  10. Microgravity

    NASA Image and Video Library

    2001-01-24

    The Diffusion-Controlled Apparatus for Microgravity (DCAM) was developed at NASA's Marshall Space Flight Center. A semi-permeable plug or fuse at the center controls the rate at which a precipitant diffuses from the reservoir chamber into the solution chamber , thus prompting protein molecules in the solution to form crystals. The principal investigator is Dr. Dan Carter of New Century Pharmaceuticals in Huntsville, AL.

  11. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. EDSE/TDSE project engineer, Zena Hester, monitors a test run of the EDSE located in the Microgravity Development Laboratory (MDL).

  12. Microgravity

    NASA Image and Video Library

    1999-04-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. Dendrites growing at .4 supercooling from a 2 stinger growth chamber for the EDSE in the Microgravity Development Lab (MDL).

  13. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows one of three arrays of air filters inside the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  14. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows a rubber glove and its attachment ring for the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  15. Microgravity

    NASA Image and Video Library

    1998-09-30

    Metal droplet levitated inside the Electrostatic Levitator (ESL). The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  16. Microgravity

    NASA Image and Video Library

    1997-03-11

    Interior lights give the Microgravity Science Glovebox (MSG) the appearance of a high-tech juke box. The European Space Agency (ESA) and NASA are developing the MSG for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  17. Microgravity

    NASA Image and Video Library

    1998-09-30

    Electrostatic levitation system inside Electrostatic Levitator (ESL) vacuum chamber. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  18. Microgravity

    NASA Image and Video Library

    1998-09-30

    Schematic of Electrostatic Levitator (ESL) electrodes and controls system. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  19. Microgravity

    NASA Image and Video Library

    1998-09-30

    General oayout of Electrostatic Levitator (ESL). The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  20. Microgravity

    NASA Image and Video Library

    1998-09-30

    Electrostatic Levitator (ESL) general layout with captions. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  1. Microgravity

    NASA Image and Video Library

    1997-03-11

    An array of miniature lamps will provide illumination to help scientists as they conduct experiments inside the Microgravity Science Glovebox (MSG). The European Space Agency (ESA) and NASA are developing the MSG for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  2. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows the access through the internal airlock (bottom right) on the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  3. Microgravity

    NASA Image and Video Library

    1994-07-08

    Onboard Space Shuttle Columbia (STS-65) Mission Specialist Leroy Chiao (top) and Mission Specialist Donald A. Thomas are seen at work in the International Microgravity Laboratory 2 (IML-2) spacelab science module. The two crewmembers are conducting experiments at the IML-2 Rack 5 Biorack (BR). Chiao places a sample in the BR incubator as Thomas handles another sample inside the BR glovebox. The glovebox is used to prepare samples for BR and slow rotating centrifuge microscope (NIZEMI) experiments.

  4. Microgravity

    NASA Image and Video Library

    2004-04-15

    Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions.

  5. Microgravity

    NASA Image and Video Library

    1997-11-15

    Pratima Rao lectures students about materials science research in space during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87, Nov. 19 - Dec. 5, 1997) in the visitor's center set up by the Isothermal Dendritic Growth Experiment (IDGE) team at Rensselaer Polytechnic Institute (RPI) in Troy, NY. IDGE, flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. Photo credit: RPI

  6. Microgravity

    NASA Image and Video Library

    1997-11-15

    Matthew Koss lectures middle-school students about materials science research in space during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87, Nov. 19 - Dec. 5, 1997) in the visitor's center set up by the Isothermal Dendritic Growth Experiment (IDGE) team at Rensselaer Polytechnic Institute (RPI)in Troy, NY. IDGE, flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. Photo credit: RPI

  7. Microgravity

    NASA Image and Video Library

    2001-05-02

    Students from DuPont Manual High School in Louisville, Kentucky participated in a video-teleconference during the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. This image is from a digital still camera; higher resolution is not available.

  8. Microgravity

    NASA Image and Video Library

    1986-06-03

    Crystals grown in the hand-held Protein Crystallization Apparatus for Microgravity (PCAM) onboard STS-61C. The PCAM has a pedestal in the center of a circular chamber, the surrounding chamber holds an absorbent reservoir that contains a solution of the precipitant. Vapor pressure differences between the protein solution and the reservoir solution force water to move from the protein solution to the reservoir. As protein concentrations increase, protein crystals begin to nucleate and grow.

  9. Microgravity

    NASA Image and Video Library

    2001-01-24

    Exterior view of Combustion Module-2 with an Experiment Module partially extracted during a crew training session. The original CM flew on the Microgravity Sciences Lab-1 and 1R in 1997. It has been refurbished and placed in new racks for flight on the STS-107 Research 1 mission in 2001. See MSFC 0100158 for a view with callouts. Glenn Research in Cleveland, OH, manages the project.

  10. Microgravity

    NASA Image and Video Library

    1999-12-01

    Dr. Donald Gilles, the Discipline Scientist for Materials Science in NASA's Microgravity Materials Science and Applications Department, demonstrates to Carl Dohrman a model of dendrites, the branch-like structures found in many metals and alloys. Dohrman was recently selected by the American Society for Metals International as their 1999 ASM International Foundation National Merit Scholar. The University of Illinois at Urbana-Champaign freshman recently toured NASA's materials science facilities at the Marshall Space Flight Center.

  11. Microgravity

    NASA Image and Video Library

    1997-11-15

    Paula Crawford (assisted by an American Sign Language interpreter) lectures students about materials science research in space during the U.S. Microgravity Payload-4 mission (STS-87, Nov. 19 - Dec. 5, 1997) in the visitor's center set up by the Isothermal Dendritic Growth Experiment (IDGE) team at Rensselaer Polytechnic Institute (RPI) in Troy, NY. IDGE, flown on three Space Shuttle mission, is yielding new insights into virtually all industrially relevant metal and alloy forming operation. Photo credit: Rensselaer Polytechnic Institute (RPI)

  12. Microgravity

    NASA Image and Video Library

    1997-11-15

    Students at Rensselaer Polytechnic Institute (RPI) in Troy, NY, monitor the progress of the Isothermal Dendritic Growth Experiment (IDGE) during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87, Nov. 19 - Dec. 5, 1997). Remote Operation Control Center (ROCC) like this one will become more common during operations with International Space Station. IDGE, flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. Photo credit: Renssenlaer Polythnic Institute (RPI)

  13. Microgravity

    NASA Image and Video Library

    1992-02-10

    The image shows a test cell of Crystal Growth experiment inside the Vapor Crystal Growth System (VCGS) furnace aboard the STS-42, International Microgravity Laboratory-1 (IML-1), mission. The goal of IML-1, a pressurized marned Spacelab module, was to explore in depth the complex effects of weightlessness of living organisms and materials processing. More than 200 scientists from 16 countires participated in the investigations.

  14. Microgravity

    NASA Image and Video Library

    1998-10-01

    Research with plants in microgravity offers many exciting opportunities to gain new insights and could improve products on Earth ranging from crop production to fragrances and food flavorings. The ASTROCULTURE facility is a lead commercial facility for plant growth and plant research in microgravity and was developed by the Wisconsin Center for Space Automation and Robotics (WSCAR), a NASA Commercial Space Center. On STS-95 it will support research that could help improve crop development leading to plants that are more disease resistant or have a higher yield and provide data on the production of plant essential oils---oils that contain the essence of the plant and provide both fragrance and flavoring. On STS-95, a flowering plant will be grown in ASTROCULTURE and samples taken using a method developed by the industry partner for this investigation. On Earth, the samples will be analyzed by gas chromatography/mass spectrometry and the data used to evaluate both the production of fragrant oils in microgravity and in the development of one or more products. The ASTROCULTURE payload uses these pourous tubes with precise pressure sensing and control for fluid delivery to the plant root tray.

  15. Microgravity

    NASA Image and Video Library

    1998-10-01

    Research with plants in microgravity offers many exciting opportunities to gain new insights and could improve products on Earth ranging from crop production to fragrances and food flavorings. The ASTROCULTURE facility is a lead commercial facility for plant growth and plant research in microgravity and was developed by the Wisconsin Center for Space Automation and Robotics (WSCAR), a NASA Commercial Space Center. On STS-95 it will support research that could help improve crop development leading to plants that are more disease resistant or have a higher yield and provide data on the production of plant essential oils---oils that contain the essence of the plant and provide both fragrance and flavoring. On STS-95, a flowering plant will be grown in ASTROCULTURE and samples taken using a method developed by the industry partner for this investigation. On Earth the samples will be analyzed by gas chromatography/mass spectrometry and the data used to evaluate both the production of fragrant oils in microgravity and in the development of one or more products.

  16. Microgravity

    NASA Image and Video Library

    2000-05-15

    John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

  17. Microgravity

    NASA Image and Video Library

    2000-12-15

    Paul Ducheyne, a principal investigator in the microgravity materials science program and head of the University of Pernsylvania's Center for Bioactive Materials and Tissue Engineering, is leading the trio as they use simulated microgravity to determine the optimal characteristics of tiny glass particles for growing bone tissue. The result could make possible a much broader range of synthetic bone-grafting applications. Even in normal gravity, bioactive glass particles enhance bone growth in laboratory tests with flat tissue cultures. Ducheyne and his team believe that using the bioactive microcarriers in a rotating bioreactor in microgravity will produce improved, three-dimensional tissue cultures. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: NASA and University of Pennsylvania Center for Bioactive Materials and Tissue Engineering.

  18. Adaptive control for payload launch vibration isolation

    NASA Astrophysics Data System (ADS)

    Jarosh, Julian R.; Agnes, Gregory S.; Karahalis, Gregory G.

    2001-07-01

    The Department of Defense has identified launch vibration isolation as a major research interest. Reducing the loads a satellite experiences during launch will greatly enhance the reliability and lifetime and decrease the payload structural mass. DoD space programs stand to benefit significantly from advances in vibration isolation technology. This study explores potential hybrid vibration isolation using adaptive control with a passive isolator. Lyapunov analysis is used to develop the structural adaptive control scheme. Simulink and Matlab simulations investigate these control methodologies on a lumped mass dynamic model of a satellite and its representative launch vehicle. The results are compared to Proportional-Integral-Derivative (PID) control and skyhook damper active control methods. The results of the modeling indicate adaptive control achieves up to a 90 percent reduction in loads on the payload when compared to the conventional active control methods. The adaptive controller compensated for the loads being transmitted to the payload from the rest of the launch vehicle. The current adaptive controller was not able to effectively control the motion of a vibrating subcomponent within the payload or the subcomponent's effect on the overall payload itself.

  19. Microgravity

    NASA Image and Video Library

    2001-10-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. Final samples from Mir and Earth appeared histologically cartilaginous throughout their entire cross sections (5-8 mm thick), with the exception of fibrous outer capsules. Constructs grown on Earth (A) appeared to have a more organized extracellular matrix with more uniform collagen orientation as compared with constructs grown on Mir (B), but the average collagen fiber diameter was similar in the two groups (22 +- 2 nm) and comparable to that previously reported for developing articular cartilage. Randomly oriented collagen in Mir samples would be consistent with previous reports that microgravity disrupts fibrillogenesis. These are transmission electron micrographs of constructs from Mir (A) and Earth (B) groups at magnifications of x3,500 and x120,000 (Inset). The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Credit: Proceedings of the National Academy of Sciences.

  20. Microgravity

    NASA Image and Video Library

    1998-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens of cartilage tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. Constructs grown on Mir (A) tended to become more spherical, whereas those grown on Earth (B) maintained their initial disc shape. These findings might be related to differences in cultivation conditions, i.e., videotapes showed that constructs floated freely in microgravity but settled and collided with the rotating vessel wall at 1g (Earth's gravity). In particular, on Mir the constructs were exposed to uniform shear and mass transfer at all surfaces such that the tissue grew equally in all directions, whereas on Earth the settling of discoid constructs tended to align their flat circular areas perpendicular to the direction of motion, increasing shear and mass transfer circumferentially such that the tissue grew preferentially in the radial direction. A and B are full cross sections of constructs from Mir and Earth groups shown at 10-power. C and D are representative areas at the construct surfaces enlarged to 200-power. They are stained red with safranin-O. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). Photo credit: Proceedings of the National Academy of Sciences.

  1. Microgravity

    NASA Image and Video Library

    2004-04-15

    Ecomaster, an affiliate of BioServe Space Technologies, this PentaPure technology has been used to purify water for our nation's Space Shuttle missions since 1981. WTC-Ecomaster of Mirneapolis, Minnesota manufactures water purification systems under the brand name PentaPure (TM). BioServe researcher Dr. George Marchin, of Kansas State University, first demonstrated the superiority of this technology and licensed it to WTC. Marchin continues to perform microgravity research in the development of new technologies for the benefit of life on Earth.

  2. Microgravity

    NASA Image and Video Library

    2001-10-01

    Students in the Young Astronaut Program at the Coca-Cola Space Science Center in Columbus, GA, constructed gloveboxes using the new NASA Student Glovebox Education Guide. The young astronauts used cardboard copier paper boxes as the heart of the glovebox. The paper boxes transformed into gloveboxes when the students pasted poster-pictures of an actual NASA microgravity science glovebox inside and outside of the paper boxes. The young astronauts then added holes for gloves and removable transparent top covers, which completed the construction of the gloveboxes. This image is from a digital still camera; higher resolution is not available.

  3. Microgravity

    NASA Image and Video Library

    2001-01-24

    Experiments with colloidal solutions of plastic microspheres suspended in a liquid serve as models of how molecules interact and form crystals. For the Dynamics of Colloidal Disorder-Order Transition (CDOT) experiment, Paul Chaikin of Princeton University has identified effects that are attributable to Earth's gravity and demonstrated that experiments are needed in the microgravity of orbit. Space experiments have produced unexpected dendritic (snowflake-like) structures. To date, the largest hard sphere crystal grown is a 3 mm single crystal grown at the cool end of a ground sample. At least two more additional flight experiments are plarned aboard the International Space Station. This image is from a video downlink.

  4. Microgravity

    NASA Image and Video Library

    1992-03-12

    The Advanced Automated Directional Solidification Furnace (AADSF) with the Experimental Apparatus Container (EAC) removed flew during the USMP-2 mission. During USMP-2, the AADSF was used to study the growth of mercury cadmium telluride crystals in microgravity by directional solidification, a process commonly used on earth to process metals and grow crystals. The furnace is tubular and has three independently controlled temperature zones . The sample travels from the hot zone of the furnace (1600 degrees F) where the material solidifies as it cools. The solidification region, known as the solid/liquid interface, moves from one end of the sample to the other at a controlled rate, thus the term directional solidification.

  5. Microgravity

    NASA Image and Video Library

    1991-09-01

    The Advanced Automated Directional Solidification Furnace (AADSF) flew during the USMP-2 mission. During USMP-2, the AADSF was used to study the growth of mercury cadmium telluride crystals in microgravity by directional solidification, a process commonly used on earth to process metals and grow crystals. The furnace is tubular and has three independently controlled temperature zones. The sample travels from the hot zone of the furnace (1600 degrees F) where the material solidifies as it cools. The solidification region, known as the solid/liquid interface, moves from one end of the sample to the other at a controlled rate, thus the term directional solidification.

  6. Microgravity

    NASA Image and Video Library

    1997-03-11

    Once the Microgravity Science Glovebox (MSG) is sealed, additional experiment items can be inserted through a small airlock at the bottom right of the work volume. It is shown here with the door open. The European Space Agency (ESA) and NASA are developing the MSG for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  7. Microgravity

    NASA Image and Video Library

    1995-04-06

    An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physcis, and combustion and processing systems. Payloads up to 1 meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 2 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

  8. Microgravity

    NASA Image and Video Library

    1995-04-06

    An experiment vehicle plunges into the deceleration at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to one-meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 3 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

  9. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows the access through the internal airlock on the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). The airlock will allow the insertion or removal of equipment and samples without opening the working volume of the glovebox. Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  10. Microgravity

    NASA Image and Video Library

    1998-09-30

    Dr. Jan Rogers and Dr. Michael Robinson operate the Electrostatic Levitator (ESL) at NASA's Marshall Space Flight Center (MSFC). The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  11. Microgravity

    NASA Image and Video Library

    1995-04-06

    An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to one meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No. 4 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

  12. Microgravity

    NASA Image and Video Library

    1995-04-06

    An experiment vehicle plunges into the deceleration pit at the end of a 5.18-second drop in the Zero-Gravity Research Facility at NASA's Glenn Research Center. The Zero-Gravity Research Facility was developed to support microgravity research and development programs that investigate various physical sciences, materials, fluid physics, and combustion and processing systems. Payloads up to 1 meter in diameter and 455 kg in weight can be accommodated. The facility has a 145-meter evacuated shaft to ensure a disturbance-free drop. This is No.1 of a sequence of 4 images. (Credit: NASA/Glenn Research Center)

  13. Microgravity

    NASA Image and Video Library

    1997-03-11

    This photo shows the access through the internal airlock (bottom right) on the Microgravity Science Glovebox (MSG) being developed by the European Space Agency (ESA) and NASA for use aboard the International Space Station (ISS). The airlock will allow the insertion or removal of equipment and samples without opening the working volume of the glovebox. Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  14. Microgravity

    NASA Image and Video Library

    1997-03-11

    Access ports, one on each side of the Microgravity Science Glovebox (MSG), will allow scientists to place large experiment items inside the MSG. The ports also provide additional glove ports (dark circle) for greater access to the interior. The European Space Agency (ESA) and NASA are developing the MSG for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  15. Microgravity

    NASA Image and Video Library

    2004-04-15

    The manipulation of organic materials--cells, tissues, and even living organisms--offers many exciting possibilities for the future from organic computers to improved aquaculture. Commercial researchers are using the microgravity environment to produce large near perfect protein crystals Research on insulin has yielded crystals that far surpass the quality of insulin crystals grown on the ground. Using these crystals industry partners are working to develop new and improved treatments for diabetes. Other researchers are exploring the possibility of producing antibiotics using plant cell cultures which could lead to both orbital production and the improvement of ground-based antibiotic production.

  16. Microgravity

    NASA Image and Video Library

    2000-01-30

    Tim Broach (seen through window) of NASA/Marshall Spce Flight Center (MSFC), demonstrates the working volume inside the Microgravity Sciences Glovebox being developed by the European Space Agency (ESA) for use aboard the U.S. Destiny laboratory module on the International Space Station (ISS). This mockup is the same size as the flight hardware. Observing are Tommy Holloway and Brewster Shaw of The Boeing Co. (center) and John-David Bartoe, ISS research manager at NASA/John Space Center and a payload specialist on Spacelab-2 mission (1985). Photo crdit: NASA/Marshall Space Flight Center (MSFC)

  17. Microgravity

    NASA Image and Video Library

    1997-03-11

    Access ports, one on each side of the Microgravity Science Glovebox (MSG), will allow scientists to place large experiment items inside the MSG. The ports also provide additional glove ports (silver disk) for greater access to the interior. The European Space Agency (ESA) and NASA are developing the MSG for use aboard the International Space Station (ISS). Scientists will use the MSG to carry out multidisciplinary studies in combustion science, fluid physics and materials science. The MSG is managed by NASA's Marshall Space Flight Center (MSFC). Photo Credit: NASA/MSFC

  18. Microgravity

    NASA Image and Video Library

    2000-01-31

    The optical bench for the Fluids Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown extracted for servicing and with the optical bench rotated 90 degrees for access to the rear elements. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  19. Microgravity

    NASA Image and Video Library

    2000-01-31

    The optical bench for the Fluid Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown in its operational configuration. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  20. Microgravity

    NASA Image and Video Library

    2000-01-31

    The combustion chamber for the Combustion Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown extracted for servicing. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  1. Microgravity

    NASA Image and Video Library

    2000-01-31

    The optical bench for the Fluids Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown extracted for servicing. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  2. Microgravity

    NASA Image and Video Library

    2000-01-31

    The combustion chamber for the Combustion Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown in its operational configuration. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  3. Microgravity

    NASA Image and Video Library

    2000-01-31

    The optical bench for the Fluids Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown extracted for servicing and with the optical bench rotated 90 degrees to access the rear elements. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  4. Microgravity

    NASA Image and Video Library

    2000-01-31

    The combustion chamber for the Combustion Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown opened for installation of burn specimens. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  5. Microgravity

    NASA Image and Video Library

    2000-01-31

    The combustion chamber for the Combustion Integrated Rack section of the Fluids and Combustion Facility (FCF) is shown extracted for servicing and with the optical bench rotated 90 degrees for access to the rear elements. The FCF will be installed, in phases, in the Destiny, the U.S. Laboratory Module of the International Space Station (ISS), and will accommodate multiple users for a range of investigations. This is an engineering mockup; the flight hardware is subject to change as designs are refined. The FCF is being developed by the Microgravity Science Division (MSD) at the NASA Glenn Research Center. (Photo credit: NASA/Marshall Space Flight Center)

  6. Microgravity

    NASA Image and Video Library

    2004-04-15

    Marshall Space Flight Center's researchers have conducted suborbital experiments with ZBLAN, an optical material capable of transmitting 100 times more signal and information than silica fibers. The next step is to process ZBLAN in a microgravity environment to stop the formation of crystallites, small crystals caused by a chemical imbalances. Scientists want to find a way to make ZBLAN an amorphous (without an internal shape) material. Producing a material such as this will have far-reaching implications on advanced communications, medical and manufacturing technologies using lasers, and a host of other products well into the 21st century.

  7. Microgravity

    NASA Image and Video Library

    1997-11-15

    Undergraduate students Kristina Wines and Dena Renzo at Rensselaer Poloytech Institute (RPI) in Troy, NY, monitor the progress of the Isothermal Dendritic Growth Experiment (IDGE) during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87), Nov. 19 - Dec.5, 1997). Remote Operations Control Center (ROCC) like this one will become more common during operations with the International Space Station. The Isothermal Dendritic Growth Experiment (IDGE), flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. Photo credit: Rensselaer Polytechnic Institute (RPI)

  8. Microgravity

    NASA Image and Video Library

    1998-02-05

    Scarning electron microscope images of the surface of ZBLAN fibers pulled in microgravity (ug) and on Earth (1g) show the crystallization that normally occurs in ground-based processing. The face of each crystal will reflect or refract a portion of the optical signal, thus degrading its quality. NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. ZBLAN is a heavy-metal fluoride glass that shows exdeptional promise for high-throughput communications with infrared lasers. Photo credit: NASA/Marshall Space Flight Center

  9. Microgravity

    NASA Image and Video Library

    1998-12-01

    The Magnetically Damped Furnace (MDF) breadboard is being developed in response to NASA's mission and goals to advance the scientific knowledge of microgravity research, materials science, and related technologies. The objective of the MDF is to dampen the fluid flows due to density gradients and surface tension gradients in conductive melts by introducing a magnetic field during the sample processing. The MDF breadboard will serve as a proof of concept that the MDF performance requirements can be attained within the International Space Station resource constraints.

  10. Microgravity

    NASA Image and Video Library

    2000-09-30

    A 3 mm drop of nickel-zirconium, heated to incandescence, hovers between electrically charged plates inside the Electrostatic Levitator (ESL). The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  11. Microgravity

    NASA Image and Video Library

    2000-07-29

    Angie Jackman, a NASA project manager in microgravity research, demonstrates the enhanced resilience of undercooled metal alloys as compared to conventional alloys. Experiments aboard the Space Shuttle helped scientists refine their understanding of the physical properties of certain metal alloys when undercooled (i.e., kept liquid below their normal solidification temperature). This new knowledge then allowed scientists to modify a terrestrial production method so they can now make limited quantities marketed under the Liquid Metal trademark. The exhibit was a part of the NASA outreach activity at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  12. Microgravity

    NASA Image and Video Library

    2001-05-31

    This diagram shows the general arrangement of the payloads to be carried by the multidisciplinary STS-107 Research-1 Space Shuttle mission in 2002. The Spacehab module will host experiments that require direct operation by the flight crew. Others with special requirements will be on the GAS Bridge Assembly sparning the payload bay. The Extended Duration Orbiter kit carries additional oxygen and hydrogen for the electricity-producing fuel cells. Research-1 experiments will cover space biology, life science, microgravity research, and commercial space product development, research sponsored by NASA's Office of Biological and Physical Research. An alternative view without callouts is available at 0101765.

  13. Microgravity

    NASA Image and Video Library

    2001-05-31

    Thisdiagram shows the general arrangement of the payloads to be carried by the multidisciplinary STS-107 Research-1 Space Shuttle mission in 2002. The Spacehab module will host experiments that require direct operation by the flight crew. Others with special requirements will be on the GAS Bridge Assembly sparning the payload bay. The Extended Duration Orbiter kit carries additional oxygen and hydrogen for the electricity-producing fuel cells. Research-1 experiments will cover space biology, life science, microgravity research, and commercial space product development, research sponsored by NASA's Office of Biological and Physical Research. An alternative view with callouts is available at 0101764.

  14. Microgravity

    NASA Image and Video Library

    2001-05-02

    Students from DuPont Manual High School in Louisville, Kentucky participated in a video-teleconference during the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. Education coordinator Twila Schneider (left) of Infinity Technology and NASA materials engineer Chris Cochrane prepare students for the on-line workshop. This image is from a digital still camera; higher resolution is not available.

  15. Microgravity

    NASA Image and Video Library

    2001-05-02

    Suzarne Nichols (12th grade) from DuPont Manual High School in Louisville, Kentucky, asks a question of on of the on-line lecturers during the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. NASA materials engineer Chris Cochrane prepare students for the on-line workshop helps two students prepare a drop demonstration. This image is from a digital still camera; higher resolution is not available.

  16. Microgravity

    NASA Image and Video Library

    2001-05-02

    Suzarne Nichols (12th grade) from DuPont Manual High School in Louisville, Kentucky, asks a question of on of the on-line lecturers during the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. Jie Ma (grade 10, at right) waits her turn to ask a question. This image is from a digital still camera; higher resolution is not available.

  17. Microgravity

    NASA Image and Video Library

    2001-05-02

    Sutta Chernubhotta (grade 10) from DuPont Manual High School in Louisville, Kentucky, asks a question of on of the on-line lecturers during the Pan-Pacific Basin Workshop on Microgravity Sciences held in Pasadena, California. The event originated at the California Science Center in Los Angeles. The DuPont Manual students patched in to the event through the distance learning lab at the Louisville Science Center. This image is from a digital still camera; higher resolution is not available.

  18. Microgravity

    NASA Image and Video Library

    2001-01-24

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Because xenon near the critical point will collapse under its own weight, experiments on Earth (green line) are limited as they get closer (toward the left) to the critical point. CVX in the microgravity of space (red line) moved into unmeasured territory that scientists had not been able to reach.

  19. Microgravity

    NASA Image and Video Library

    2004-04-15

    Some of the earliest concerns about fluid behavior in microgravity was the management of propellants in spacecraft tanks as they orbited the Earth. On the ground, gravity pulls a fluid to a bottom of a tank (ig, left). In orbit, fluid behavior depends on surface tension, viscosity, wetting effects with the container wall, and other factors. In some cases, a propellant can wet a tank and leave a large gas bubbles in the center (ug, right). Similar probelms can affect much smaller experiments using fluids in small spaces. Photo credit: NASA/Glenn Research Center.

  20. Microgravity

    NASA Image and Video Library

    1997-04-01

    Apfel's excellent match: This series of photos shows a water drop containing a surfactant (Triton-100) as it experiences a complete cycle of superoscillation on U.S. Microgravity Lab-2 (USML-2; October 1995). The time in seconds appears under the photos. The figures above the photos are the oscillation shapes predicted by a numerical model. The time shown with the predictions is nondimensional. Robert Apfel (Yale University) used the Drop Physics Module on USML-2 to explore the effect of surfactants on liquid drops. Apfel's research of surfactants may contribute to improvements in a variety of industrial processes, including oil recovery and environmental cleanup.

  1. Microgravity

    NASA Image and Video Library

    1996-03-24

    Astronaut Michael Clifford places a liquid nitrogen Dewar containing frozen protein solutions aboard Russia's space station Mir during a visit by the Space Shuttle (STS-76). The protein samples were flash-frozen on Earth and will be allowed to thaw and crystallize in the microgravity environment on Mir Space Station. A later crew will return the Dewar to Earth for sample analysis. Dr. Alexander McPherson of the University of California at Riverside is the principal investigator. Photo credit: NASA/Johnson Space Center.

  2. Microgravity

    NASA Image and Video Library

    2004-04-15

    The Commercial Vapor Diffusion Apparatus will be used to perform 128 individual crystal growth investigations for commercial and science research. These experiments will grow crystals of several different proteins, including HIV-1 Protease Inhibitor, Glycogen Phosphorylase A, and NAD Synthetase. The Commercial Vapor Diffusion Apparatus supports multiple commercial investigations within a controlled environment. The goal of the Commercial Protein Crystal Growth payload on STS-95 is to grow large, high-quality crystals of several different proteins of interest to industry, and to continue to refine the technology and procedures used in microgravity for this important commercial research.

  3. Microgravity

    NASA Image and Video Library

    1996-09-20

    Astronaut Tom Akers places a liquid nitrogen Dewar containing frozen protein solutions aboard Russia's space Station Mir during a visit by the Space Shuttle (STS-79). The protein samples were flash-frozen on Earth and will be allowed to thaw and crystallize in the microgravity environment on Mir Space Station. A later crew will return the Dewar to Earth for sample analysis. Dr. Alexander McPherson of the University of California at Riverside is the principal investigator. Photo credit: NASA/Johnson Space Center.

  4. Microgravity

    NASA Image and Video Library

    2001-04-04

    One of NASA's newest education publications made its debut at the arnual National Council of Teachers of Mathematics (NCTM) conference held in Orlando, Florida April 5-7. How High Is It? An Educator's Guide with Activities Focused on Scale Models of Distances was presented by Carla Rosenberg of the National Center for Microgravity Research at Glenn Research Center. Rosenberg, an author of the Guide, led teachers in several hands-on activities from the Guide. This image is from a digital still camera; higher resolution is not available.

  5. Microgravity

    NASA Image and Video Library

    1998-09-30

    Graph depicting Electrostatic Levitator (ESL) heating and cooling cycle to achieve undercooling of liquid metals. The ESL uses static electricity to suspend an object (about 3-4 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contracting the container or any instruments, conditions that would alter the readings. The electrostatic Levitator is one of several tools used in NASA's microgravity matierials sciences program.

  6. Microgravity

    NASA Image and Video Library

    2000-07-29

    Paul Luz (right), an aerospace flight system engineer at NASA's Marshall Space Flight Center (MSFC), discusses microgravity research with a visitor at AirVenture 2000. Part of the NASA exhibits included demonstration of knowledge gained from micorgravity research aboard the Space Shuttle. These include liquid metal (Liquid metal demonstrator is three plastic drop tubes at center) and dendritic growth (in front of Luz), both leading to improvements in processes on Earth. The exhibit was part of the NASA outreach activity at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  7. Microgravity

    NASA Image and Video Library

    1997-11-15

    Matthew Koss (forground) and Martin Glicksman (rear), principal investigator and lead scientist (respectively), review plans for the next step in the Isothermal Dendritic Growth Experiment (IDGE) during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87, Nov. 19 - Dec. 5, 1997). Remote Operations Control Center (ROCC) like this one, at Rensselaer Polytechnic Institute (RPI) in Troy, NY, will become more common during operations with the International Space Station. IDGE, flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relavent metal and alloy forming operations. Photo credit: Rensselaer Polytechnic Institute (RPI)

  8. Microgravity

    NASA Image and Video Library

    1995-10-20

    Payload specialist Albert Sacco Jr. inspects a crystal in a cylindrical autoclave on the mid-deck of the earth-orbiting space shuttle Columbia. This Zeolite Crystal Growth (ZCG) experiment was one of a few U.S. Microgravity Laboratory (USML-2) experiments that were conducted in both the Shuttle proper and its primary cargo's science module in the payload bay. Most of the experiments were conducted solely in the science module. Sacco was one of two guest researchers who joined five NASA astronauts for 16 days of Earth-orbit.

  9. Microgravity

    NASA Image and Video Library

    1992-02-21

    Vapor Crystal Growth System developed in IML-1, Mercuric Iodide Crystal grown in microgravity FES/VCGS (Fluids Experiment System/Vapor Crystal Growth Facility). During the mission, mercury iodide source material was heated, vaporized, and transported to a seed crystal where the vapor condensed. Mercury iodide crystals have practical uses as sensitive X-ray and gamma-ray detectors. In addition to their excellent optical properties, these crystals can operate at room temperature, which makes them useful for portable detector devices for nuclear power plant monitoring, natural resource prospecting, biomedical applications, and astronomical observing.

  10. Microgravity

    NASA Image and Video Library

    1998-09-30

    Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  11. Microgravity

    NASA Image and Video Library

    1997-08-01

    STS-94 Payload Specialist Roger K. Crouch is helped into his launch/entry suit by a suit technician in the Operations and Checkout (OC) building after the suit has been given a pressure test. He is the Chief Scientist of the NASA Microgravity Space and Applications Division. He also has served as a Program Scientist for previous missions and is an expert in semiconductor crystal growth. Crouch and six other crewmembers prepare to depart the OC and head for Launch Pad 39a, where the Space Shuttle Columbia will lift off.

  12. Microgravity

    NASA Image and Video Library

    2000-07-01

    Engineering bench system hardware for the Mechanics of Granular Materials (MGM) experiment is tested on a lab bench at the University of Colorado in Boulder. This is done in a horizontal arrangement to reduce pressure differences so the tests more closely resemble behavior in the microgravity of space. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: University of Colorado at Boulder).

  13. Microgravity

    NASA Image and Video Library

    1998-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  14. Method of vibration isolating an aircraft engine

    NASA Technical Reports Server (NTRS)

    Bender, Stanley I. (Inventor); Butler, Lawrence (Inventor); Dawes, Peter W. (Inventor)

    1991-01-01

    A method for coupling an engine to a support frame for mounting to a fuselage of an aircraft using a three point vibration isolating mounting system in which the load reactive forces at each mounting point are statically and dynamically determined. A first vibration isolating mount pivotably couples a first end of an elongated support beam to a stator portion of an engine with the pivoting action of the vibration mount being oriented such that it is pivotable about a line parallel to a center line of the engine. An aft end of the supporting frame is coupled to the engine through an additional pair of vibration isolating mounts with the mounts being oriented such that they are pivotable about a circumference of the engine. The aft mounts are symmetrically spaced to each side of the supporting frame by 45 degrees. The relative orientation between the front mount and the pair of rear mounts is such that only the rear mounts provide load reactive forces parallel to the engine center line, in support of the engine to the aircraft against thrust forces. The forward mount is oriented so as to provide only radial forces to the engine and some lifting forces to maintain the engine in position adjacent a fuselage. Since each mount is connected to provide specific forces to support the engine, forces required of each mount are statically and dynamically determinable.

  15. Effects of vibration (G-jitters) on convection in micro-gravity

    NASA Technical Reports Server (NTRS)

    Wang, Francis C.

    1994-01-01

    To obtain high quality crystals, it is desirable to maintain a diffusion-limited transport process in a planar solidification surface between the solid and the melt during the crystal growth process. Due to the presence of buoyancy-driven convection, however, this situation is difficult to maintain on Earth. The microgravity environment of an orbiting space laboratory presents an alternative worth pursuing. With reduced gravity, convections very much suppressed in a space laboratory, making the environment more conducive for growing crystals with better quality. However, a space laboratory is not immune from any undesirable disturbances. Nonuniform and transient accelerations such as vibrations, g-jitters, and impulsive accelerations exist as a result of crew activities, space maneuvering, and the operations of on-board equipment. Measurements conducted on-board a U.S. Spacelab mission showed the existence of vibrations in the frequency range of 1 to 100 Hz. It was reported that a dominant mode of 17 Hz and harmonics of 54 Hz were observed and these were attributed to antenna operations. The vibration is not limited to any single plane but exists in all directions. Some data from the Russian MIR space station indicates the existence of vibration also at this frequency range.

  16. Microgravity

    NASA Image and Video Library

    2001-01-24

    The Water Mist commercial research program is scheduled to fly an investigation on STS-107 in 2002 in the updated Combustion Module (CM-2), a sophisticated combustion chamber plus diagnostic equipment. The Center for the Commercial Applications of Combustion in Space (CCACS), a NASA Commercial Space Center located at the Colorado School of Mines, is investigating the properties of mist fire suppression in microgravity with Industry Partner Environmental Engineering Concepts. These experiments consist of varying water droplet sizes and water mist concentrations applied to flame fronts of different propane/air mixtures. Observations from these tests will provide valuable information on the change of flame speed in the presence of water mist. Shown here is a flame front propagating through the Mist flame tube during 1-g testing at NASA/Glenn Research Center.

  17. Microgravity

    NASA Image and Video Library

    1985-05-04

    A 16mm film frame shows convective regions inside silicone oil playing the part of a stellar atmosphere in the Geophysical Fluid Flow Cell (GFFC). An electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. Numbers of the frame indicate temperatures and other conditions. This image is from the Spacelab-3 flight in 1985. GFFC was reflown on U.S. Microgravity Laboratory-2 in 1995. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center. (Credit: NASA/Marshall Space Flight Center)

  18. Microgravity

    NASA Image and Video Library

    1995-10-10

    This composite image depicts one set of flow patterns simulated in the Geophysical Fluid Flow Cell (GFFC) that flew on two Spacelab missions. Silicone oil served as the atmosphere around a rotating steel hemisphere (dotted circle) and an electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. GFFC flew on Spacelab-3 in 1985 and U.S. Microgravity Laboratory-2 in 1995. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center. (Credit: NASA/Marshall Space Flight Center)

  19. Microgravity

    NASA Image and Video Library

    1992-07-15

    A steel hemisphere was at the core of the Geophysical Fluid Flow Cell (GFFC) that flew on two Spacelab missions. It was capped by a sapphire dome. Silicone oil between the two played the part of a steller atmosphere. An electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. GFFC flew on Spacelab-3 in 1985 and U.S. Microgravity Laboratory-2 in 1995. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center. (Credit: NASA/Marshall Space Flight Center)

  20. Microgravity

    NASA Image and Video Library

    1995-10-20

    This drawing depicts one set of flow patterns simulated in the Geophysical Fluid Flow Cell (GFFC) that flew on two Spacelab missions. Silicone oil served as the atmosphere around a rotating steel hemisphere (dotted circle) and an electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center (MSFC). An Acrobat PDF copy of this drawing is available at http://microgravity.nasa.gov/gallery. (Credit: NASA/Marshall Space Flight Center)

  1. Microgravity

    NASA Image and Video Library

    1998-09-30

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  2. Microgravity

    NASA Image and Video Library

    2000-12-15

    NASA is looking to biological techniques that are millions of years old to help it develop new materials and technologies for the 21st century. Sponsored by NASA, Viola Vogel, director of Washington University's Center for Nanotechnology and a principal investigator for the microgravity biotechnology program, is researching a monorail on a nanoscale to learn how to control translational motion of motor proteins in nonbiological environments in order to transport cargo between user-specified locations. Shear-deposition of Teflon on glass (top) is used in Viola Vogel's lab to create a nanogrooved surface. The topography controls the path that microtubules take as they shuttle nano-sized cargo between user-defined destinations.

  3. Microgravity

    NASA Image and Video Library

    2004-04-15

    Researcher Dr. Yi Li developed a technique to manipulate certain characteristics of plant growth such as anit-senescence. For example, the tobacco leaf was clipped from a transgenic plant (right), and a wildtype plant (left). During ground-based laboratory studies, both leaves were left in a darkened area for 4 months. When retrieved, the wildtype plant leaf was dried-out and the transgenic leaf remained fresh and green. A variation of this technology that involves manipulating plant hormones has been conducted in space-based studies on tomato plants through BioServe Space Technologies. The transport and distribution of auxin, an important plant hormone has shown to be influenced by microgravity, which could lead to improving the quality of fruits and vegetables grown on Earth.

  4. Microgravity

    NASA Image and Video Library

    1992-06-25

    Space Shuttle Columbia (STS-50) onboard photo of astronauts working in United States Microgravity Laboratory (USML-1). USML-1 will fly in orbit for extended periods of time attached to the Shuttle, providing greater opportunities for research in materials science, fluid dynamics, biotechnology, and combustion science. The scientific data gained from the USML-1 missions will constitute a landmark in space science, pioneering investigations into the role of gravity in a wide array of important processes and phenomena. In addition, the missions will also provide much of the experience in performing research in space and in the design of instruments needed for Space Station Freedom and the programs to follow in the 21st Century.

  5. Microgravity

    NASA Image and Video Library

    2004-04-15

    Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

  6. Microgravity

    NASA Image and Video Library

    1994-02-16

    These Vapor Diffusion Apparatus (VDA) trays were first flown in the Thermal Enclosure System (TES) during the USMP-2 (STS-62) mission. Each tray can hold 20 protein crystal growth chambers. Each chamber contains a double-barrel syringe; one barrel holds protein crystal solution and the other holds precipitant agent solution. During the microgravity mission, a torque device is used to simultaneously retract the plugs in all 20 syringes. The two solutions in each chamber are then mixed. After mixing, droplets of the combined solutions are moved onto the syringe tips so vapor diffusion can begin. During the length of the mission, protein crystals are grown in the droplets. Shortly before the Shuttle's return to Earth, the experiment is deactivated by retracting the droplets containing protein crystals, back into the syringes.

  7. Microgravity

    NASA Image and Video Library

    2003-01-22

    One concern about human adaptation to space is how returning from the microgravity of orbit to Earth can affect an astronaut's ability to fly safely. There are monitors and infrared video cameras to measure eye movements without having to affect the crew member. A computer screen provides moving images which the eye tracks while the brain determines what it is seeing. A video camera records movement of the subject's eyes. Researchers can then correlate perception and response. Test subjects perceive different images when a moving object is covered by a mask that is visible or invisible (above). Early results challenge the accepted theory that smooth pursuit -- the fluid eye movement that humans and primates have -- does not involve the higher brain. NASA results show that: Eye movement can predict human perceptual performance, smooth pursuit and saccadic (quick or ballistic) movement share some signal pathways, and common factors can make both smooth pursuit and visual perception produce errors in motor responses.

  8. Microgravity

    NASA Image and Video Library

    1998-10-01

    CGBA, a facility developed by BioServe Space Technologies, a NASA Commercial Generic Bioprocessing Space Center, allows a variety of sophisticated bioprocessing research to be performed using a common device. The Fluids Processing Apparatus is essentially a microgravity test tube that allows a variety of complex investigations to be performed in space. This is a glass barrel containing several chambers separated by rubber stoppers. Eight FPAs are placed together in a Group Activation Pack (GAP), which allows all of the research to be started simultaneously by turning a single crank. Eight GAPs, or similar-sized payloads, can be stored in a single CGBA temperature controlled locker, which now uses motor drives to automatically turn the cranks to start and stop experiments. On STS-95, research efforts cover eight major areas that will benefit Earth-based products ranging from the production of pharmaceuticals to fish hatcheries.

  9. Microgravity

    NASA Image and Video Library

    2000-07-07

    The Transient Dentritic Solidification Experiment (TDSE) is being developed as a candidate for flight aboard the International Space Station. TDSE will study the growth of dentrites (treelike crystalline structures) in a transparent material (succinonitrile or SCN) that mimics the behavior of widely used iron-based metals. Basic work by three Space Shuttle flights (STS-62, STS-75, and STS-87) of the Isothermal Dendritic Growth Experiment (IDGE) is yielding new insights into virtually all industrially relevant metal and alloy forming operations. The TDSE is similar to IDGE, but will maintain a constant temperature while varying pressure on the dentrites. Shown here is a cutaway of the isothermal bath containing its growth cell at the heart of the TDSE. The principal investigator is Matthew Koss of College of the Holy Cross in Worcester, MA. Note: an Acrobat PDF version is available from http://microgravity.nasa.gov/gallery

  10. Microgravity

    NASA Image and Video Library

    2001-01-24

    As a liquefied metal solidifies, particles dispersed in the liquid are either pushed ahead of or engulfed by the moving solidification front. Similar effects can be seen when the ground freezes and pushes large particles out of the soil. The Particle Engulfment and Pushing (PEP) experiment, conducted aboard the fourth U.S. Microgravity Payload (USMP-4) mission in 1997, used a glass and plastic beads suspended in a transparent liquid. The liquid was then frozen, trapping or pushing the particles as the solidifying front moved. This simulated the formation of advanced alloys and composite materials. Such studies help scientists to understand how to improve the processes for making advanced materials on Earth. The principal investigator is Dr. Doru Stefanescu of the University of Alabama. This image is from a video downlink.

  11. Microgravity

    NASA Image and Video Library

    1998-05-15

    While the microgravity environment of orbit eliminates a number of effects that impede the formation of materials on Earth, the change can also cause new, unwanted effects. A mysterious phenomenon, known as detached solidification, apparently stems from a small hydrostatic force that turns out to be pervasive. The contact of the solid with the ampoule transfers stress to the growing crystal and causing unwanted dislocations and twins. William Wilcox and Liya Regel of Clarkson University theorize that the melt is in contact with the ampoule wall, while the solid is not, and the melt and solid are cornected by a meniscus. Their work is sponsored by NASA's Office of Biological and Physical Researcxh, and builds on earlier work by Dr. David Larson of the State University of New York at Stony Brook.

  12. Microgravity

    NASA Image and Video Library

    2004-04-15

    This is an image of a colloidal crystal from the CDOT-2 investigation flown on STS-95. There are so many colloidal particles in this sample that it behaves like a glass. In the laboratory on Earth, the sample remained in an amorphous state, showing no sign of crystal growth. In microgravity the sample crystallized in 3 days, as did the other glassy colloidal samples examined in the CDOT-2 experiment. During the investigation, crystallization occurred in samples that had a volume fraction (number of particles per total volume) larger than the formerly reported glass transition of 0.58. This has great implications for theories of the structural glass transition. These crystals were strong enough to survive space shuttle re-entry and landing.

  13. Microgravity

    NASA Image and Video Library

    1998-09-30

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  14. Microgravity

    NASA Image and Video Library

    2004-04-15

    Bacillus thuringiensis (Bt), a natural bacteria found all over the Earth, has a fairly novel way of getting rid of unwanted insects. Bt forms a protein substance (shown on the right) that is not harmful to humans, birds, fish or other vertebrates. When eaten by insect larvae the protein causes a fatal loss of appetite. For over 25 years agricultural chemical companies have relied heavily upon safe Bt pesticides. New space based research promises to give the insecticide a new dimension in effectiveness and applicability. Researchers from the Consortium for Materials Development in Space along with industrial affiliates such as Abott Labs and Pern State University flew Bt on a Space Shuttle mission in the fall of 1996. Researchers expect that the Shuttle's microgravity environment will reveal new information about the protein that will make it more effective against a wider variety of pests.

  15. Microgravity

    NASA Image and Video Library

    1994-07-10

    TEMPUS, an electromagnetic levitation facility that allows containerless processing of metallic samples in microgravity, first flew on the IML-2 Spacelab mission. The principle of electromagnetic levitation is used commonly in ground-based experiments to melt and then cool metallic melts below their freezing points without solidification occurring. The TEMPUS operation is controlled by its own microprocessor system; although commands may be sent remotely from the ground and real time adjustments may be made by the crew. Two video cameras, a two-color pyrometer for measuring sample temperatures, and a fast infrared detector for monitoring solidification spikes, will be mounted to the process chamber to facilitate observation and analysis. In addition, a dedicated high-resolution video camera can be attached to the TEMPUS to measure the sample volume precisely.

  16. Design-Filter Selection for H2 Control of Microgravity Isolation Systems: A Single-Degree-of-Freedom Case Study

    NASA Technical Reports Server (NTRS)

    Hampton, R. David; Whorton, Mark S.

    2000-01-01

    Many microgravity space-science experiments require active vibration isolation, to attain suitably low levels of background acceleration for useful experimental results. The design of state-space controllers by optimal control methods requires judicious choices of frequency-weighting design filters. Kinematic coupling among states greatly clouds designer intuition in the choices of these filters, and the masking effects of the state observations cloud the process further. Recent research into the practical application of H2 synthesis methods to such problems, indicates that certain steps can lead to state frequency-weighting design-filter choices with substantially improved promise of usefulness, even in the face of these difficulties. In choosing these filters on the states, one considers their relationships to corresponding design filters on appropriate pseudo-sensitivity- and pseudo-complementary-sensitivity functions. This paper investigates the application of these considerations to a single-degree-of-freedom microgravity vibration-isolation test case. Significant observations that were noted during the design process are presented. along with explanations based on the existent theory for such problems.

  17. Microgravity

    NASA Image and Video Library

    1997-11-15

    The Isothermal Dendritic Growth Experiment (IDGE), flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. IDGE used transparent organic liquids that form dendrites (treelike structures) similar to those inside metal alloys. Comparing Earth-based and space-based dendrite growth velocity, tip size and shape provides a better understanding of the fundamentals of dentritic growth, including gravity's effects. Shalowgraphic images of pivalic acid (PVA) dendrites forming from the melt show the subtle but distinct effects of gravity-driven heat convection on dentritic growth. In orbit, the dendrite grows as its latent heat is liberated by heat conduction. This yields a blunt dendrite tip. On Earth, heat is carried away by both conduction and gravity-driven convection. This yields a sharper dendrite tip. In addition, under terrestrial conditions, the sidebranches growing in the direction of gravity are augmented as gravity helps carry heat out of the way of the growing sidebranches as opposed to microgravity conditions where no augmentation takes place. IDGE was developed by Rensselaer Polytechnic Institute and NASA/Glenn Research Center. Advanced follow-on experiments are being developed for flight on the International Space Station. Photo Credit: NASA/Glenn Research Center

  18. Microgravity

    NASA Image and Video Library

    2000-05-01

    The structure of the Satellite Tobacco Mosaic Viurus (STMV)--one of the smallest viruses known--has been successfully reduced using STMV crystals grown aboard the Space Shuttle in 1992 and 1994. The STMV crystals were up to 30 times the volume of any seen in the laboratory. At the time they gave the best resolution data ever obtained on any virus crystal. STMV is a small icosahedral plant virus, consisting of a protein shell made up of 60 identical protein subunits of molecular weight 17,500. Particularly noteworthy is the fact that, in contrast to the crystals grown on Earth, the crystals grown under microgravity conditions were visually perfect, with no striations or clumping of crystals. Furthermore, the x-ray diffraction data obtained from the space-grown crystals was of a much higher quality than the best data available at that time from ground-based crystals. This stylized ribbon model shows the protein coat in white and the nucleic acid in yellow. STMV is used because it is a simple protein to work with; studies are unrelated to tobacco. Credit: Dr. Alex McPherson, University of California at Irvin.

  19. Microgravity

    NASA Image and Video Library

    2000-05-01

    The structure of the Satellite Tobacco Mosaic Virus (STMV)--one of the smallest viruses known--has been successfully deduced using STMV crystals grown aboard the Space Shuttle in 1992 and 1994. The STMV crystals were up to 30 times the volume of any seen in the laboratory. At the same time they gave the best resolution data ever obtained on any virus crystal. STMV is a small icosahedral plant virus, consisting of a protein shell made up of 60 identical protein subunits of molecular weight 17,500. Particularly noteworthy is the fact that, in contrast to the crystal grown on Earth, the crystals grown under microgravity conditions were viusally perfect, with no striations or clumping of crystals. Furthermore, the X-ray diffraction data obtained from the space-grown crystals was of a much higher quality than the best data available at that time from ground-based crystals. This computer model shows the external coating or capsid. STMV is used because it is a simple protein to work with; studies are unrelated to tobacco. Credit: Dr. Alex McPherson, Univeristy of California at Irvin.

  20. Microgravity

    NASA Image and Video Library

    2001-01-24

    Close-up view of the Binary Colloidal Alloy Test during an experiment run aboard the Russian Mir space station. BCAT is part of an extensive series of experiments plarned to investigate the fundamental properties of colloids so that scientists can make colloids more useful for technological applications. Some of the colloids studied in BCAT are made of two different sized particles (binary colloidal alloys) that are very tiny, uniform plastic spheres. Under the proper conditions, these colloids can arrange themselves in a pattern to form crystals, which may have many unique properties that may form the basis of new classes of light switches, displays, and optical devices that can fuel the evolution of the next generation of computer and communication technologies. This Slow Growth hardware consisted of a 35-mm camera aimed toward a module which contained 10 separate colloid samples. To begin the experiment, one of the astronauts would mix the samples to disperse the colloidal particles. Then the hardware operated autonomously, taking photos of the colloidal samples over a 90-day period. The investigation proved that gravity plays a central role in the formation and stability of these types of colloidal crystal structures. The investigation also helped identify the optimum conditions for the formation of colloidal crystals, which will be used for optimizing future microgravity experiments in the study of colloidal physics. Dr. David Weitz of the University of Pennsylvania and Dr. Peter Pusey of the University of Edinburgh, United Kingdom, are the principal investigators.

  1. Microgravity

    NASA Image and Video Library

    1998-01-25

    Astronaut James Reilly uses a laptop computer monitor the Mechanics of Granular Materials (MGM) experiment during STS-89. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

  2. Microgravity

    NASA Image and Video Library

    2000-07-01

    Key persornel in the Mechanics of Granular Materials (MGM) experiment at the University of Colorado at Boulder include Tawnya Ferbiak (software engineer), Susan Batiste (research assistant), and Christina Winkler (graduate research assistant). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: University of Colorado at Boulder).

  3. Microgravity

    NASA Image and Video Library

    2004-04-15

    Proteins are the building blocks of our bodies and the living world around us. Within our bodies proteins make it possible for red blood cells to carry oxygen throughout the body. Others help transmit nerve impulses so we can hear, smell and feel the world around us. While others play a crucial role in preventing or causing disease. If the structure of a protein is known, then companies can develop new or improved drugs to fight the disease of which the protein is a part. To determine protein structure, researchers must grow near-perfect crystals of the protein. On Earth convection currents, sedimentation and other gravity-induced phenomena hamper crystal growth efforts. In microgravity researchers can grow near-perfect crystals in an environment free of these effects. Because of the enormous potential for new pharmaceutical products the Center for Macromolecular Crystallography--the NASA Commercial Space Center responsible for commercial protein crystal growth efforts has more than fifty major industry and academic partners. Research on crystals of human insulin could lead to improved treatments for diabetes.

  4. Microgravity

    NASA Image and Video Library

    1998-01-05

    The Interferometer Protein Crystal Growth (IPCG) experiment was designed to measure details of how protein molecules move through a fluid. It was flown on the STS-86 mission for use aboard Russian Space Station Mir in 1998. It studied aspects of how crystals grow - and what conditions lead to the best crystals, details that remain a mystery. IPCG produces interference patterns by spilitting then recombining laser light. This let scientists see how fluid densities - and molecular diffusion - change around a crystal as it grows in microgravity. The heart of the IPCG apparatus is the interferometer cell comprising the optical bench, microscope, other optics, and video camera. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visuzlizes crystals and conditions around them as they grow inside the cell. This view shows a large growth cell. The principal investigator was Dr. Alexander McPherson of University of California, Irvine. Co-investigators are William Witherow and Dr. Marc Pusey of NASA's Marshall Space Flight Center (MSFC).

  5. Microgravity

    NASA Image and Video Library

    1998-01-05

    The Interferometer Protein Crstal Growth (IPCG) experiment was designed to measure details of how protein molecules move through a fluid. It was flown on the STS-86 mission for use aboard Russin Space Station Mir in 1998. It studied aspects of how crystals grow - and what conditions lead to the best crystals, details that remain a mystery. IPCG produces interference patterns by splitting then recombining laser light. This let scientists see how fluid densities - and molecular diffusion - change around a crystal as it grows in microgravity. The heart of the IPCG apparatus is the interferometer cell comprising the optical bench, microscope, other optics, and video camera. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visualizes crystals and conditions around them as they grow inside the cell. This view shows the complete apparatus. The principal investigator was Dr. Alexander McPherson of the University of California, Irvin. Co-investigators are William Witherow and Dr. Marc Pusey of NASA's Marshall Space Flight Center

  6. Microgravity

    NASA Image and Video Library

    1998-01-05

    The Interferometer Protein Crystal Growth (IPCG) experiment was designed to measure details of how protein molecules move through a fluid. It was flown on the STS-86 mission for use aboard Russian Space Station Mir in 1998. It studied aspects of how crystals grow - and what conditions lead to the best crystals, details that remain a mystery. IPCG produces interference patterns by spilitting then recombining laser light. This let scientists see how fluid densities - and molecular diffusion - change around a crystal as it grows in microgravity. The heart of the IPCG apparatus is the interferometer cell comprising the optical bench, microscope, other optics, and video camera. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visuzlizes crystals and conditions around them as they grow inside the cell. This diagram shows the optical layout. The principal investigator was Dr. Alexander McPherson of University of California, Irvine. Co-investigators are William Witherow and Dr. Marc Pusey of NASA's Marshall Space Flight Center (MSFC).

  7. Microgravity

    NASA Image and Video Library

    1998-01-05

    The Interferometer Protein Crystal Growth (IPCG) experiment was designed to measure details of how protein molecules move through a fluid. It was flown on the STS-86 mission for use aboard Russian Space Station Mir in 1998. It studied aspects of how crystals grow - and what conditions lead to the best crystals, details that remain a mystery. IPCG produces interference patterns by spilitting then recombining laser light. This let scientists see how fluid densities - and molecular diffusion - change around a crystal as it grows in microgravity. The heart of the IPCG apparatus is the interferometer cell comprising the optical bench, microscope, other optics, and video camera. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visuzlizes crystals and conditions around them as they grow inside the cell. This view shows interferograms produced in ground tests. The principal investigator was Dr. Alexander McPherson of University of California, Irvine. Co-investigators are William Witherow and Dr. Marc Pusey of NASA's Marshall Space Flight Center (MSFC).

  8. Microgravity

    NASA Image and Video Library

    1998-01-05

    The Interferometer Protein Crystal Growth (IPCG) experiment was designed to measure details of how protein molecules move through a fluid. It was flown on the STS-86 mission for use aboard Russian Space Station Mir in 1998. It studied aspects of how crystals grow - and what conditions lead to the best crystals, details that remain a mystery. IPCG produces interference patterns by spilitting then recombining laser light. This let scientists see how fluid densities - and molecular diffusion - change around a crystal as it grows in microgravity. The heart of the IPCG apparatus is the interferometer cell comprising the optical bench, microscope, other optics, and video camera. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visuzlizes crystals and conditions around them as they grow inside the cell. This diagram shows the growth cells. The principal investigator was Dr. Alexander McPherson of University of California, Irvine. Co-investigators are William Witherow and Dr. Marc Pusey of NASA's Marshall Space Flight Center (MSFC).

  9. Microgravity

    NASA Image and Video Library

    2001-06-01

    Cells cultured on Earth (left) typically settle quickly on the bottom of culture vessels due to gravity. In microgravity (right), cells remain suspended and aggregate to form three-dimensional tissue. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  10. Microgravity

    NASA Image and Video Library

    2001-05-31

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Cell constructs grown in a rotating bioreactor on Earth (left) eventually become too large to stay suspended in the nutrient media. In the microgravity of orbit, the cells stay suspended. Rotation then is needed for gentle stirring to replenish the media around the cells.

  11. Microgravity

    NASA Image and Video Library

    2000-05-05

    A test cell for Mechanics of Granular Materials (MGM) experiment is tested for long-term storage with water in the system as plarned for STS-107. This view shows the top of the sand column with the metal platten removed. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

  12. Microgravity

    NASA Image and Video Library

    1998-01-25

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from a series of horizontal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  13. Microgravity

    NASA Image and Video Library

    1996-09-18

    Astronaut Jay Apt installs Mechanics of Granular Materials (MGM0 test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: NASA/John Space Center).

  14. Microgravity

    NASA Image and Video Library

    1998-01-25

    CT scans of the specimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from three orthogonal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: Los Alamos National Laboratory and the University of Colorado at Boulder).

  15. Microgravity

    NASA Image and Video Library

    1998-01-25

    A test cell for Mechanics of Granular Materials (MGM) experiment is shown approximately 20 and 60 minutes after the start of an experiment on STS-89. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

  16. Microgravity

    NASA Image and Video Library

    2000-05-05

    A test cell for Mechanics of Granular Materials (MGM) experiment is tested for long-term storage with water in the system as plarned for STS-107. This view shows the compressed sand column with the protective water jacket removed. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

  17. Microgravity

    NASA Image and Video Library

    1998-01-25

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. These views depict vertical slices from side to middle of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  18. Microgravity

    NASA Image and Video Library

    2000-07-01

    Mechanics of Granular Materials (MGM) flight hardware takes two twin double locker assemblies in the Space Shuttle middeck or the Spacehab module. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: NASA/MSFC).

  19. Microgravity

    NASA Image and Video Library

    2000-07-01

    What appear to be boulders fresh from a tumble down a mountain are really grains of Ottawa sand, a standard material used in civil engineering tests and also used in the Mechanics of Granular Materials (MGM) experiment. The craggy surface shows how sand grans have faces that can cause friction as they roll and slide against each other, or even causing sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM uses the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. These images are from an Electron Spectroscopy for Chemical Analysis (ESCA) study conducted by Dr. Binayak Panda of IITRI for Marshall Space Flight Center (MSFC). (Credit: NASA/MSFC)

  20. Microgravity

    NASA Image and Video Library

    1998-01-25

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view depict horizontal slices from top to bottom of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  1. Microgravity

    NASA Image and Video Library

    1966-11-24

    Lunar Orbiter 2 oblique northward view towards Copernicus crater on the Moon shows crater wall slumping caused by soil liquefaction following the impact that formed the crater. The crater is about 100 km in diameter. The central peaks are visible towards the top of the image, rising about 400 m above the crater floor, and stretching for about 15 km. The northern wall of the crater is in the background. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: University of Colorado at Boulder).

  2. Microgravity

    NASA Image and Video Library

    1996-09-18

    One of three Mechanics of Granular Materials (MGM) test cells after flight on STS-79 and before impregnation with resin. Note that the sand column has bulged in the middle, and that the top of the column is several inches lower than the top of the plastic enclosure. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: University of Colorado at Boulder

  3. Microgravity

    NASA Image and Video Library

    1996-09-18

    Astronaut Carl Walz installs Mechanics of Granular Materials (MGM) test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/John Space Center

  4. Microgravity

    NASA Image and Video Library

    1997-09-09

    A test cell for the Mechanics of Granular Materials (MGM) experiment is shown in its on-orbit configuration in Spacehab during preparations for STS-89. The twin locker to the left contains the hydraulic system to operate the experiment. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Note: Because the image on the screen was muted in the original image, its brightness and contrast are boosted in this rendering to make the test cell more visible. Credit: NASA/Marshall Space Flight Center (MSFC)

  5. Microgravity

    NASA Image and Video Library

    2000-07-01

    The packing of particles can change radically during cyclic loading such as in an earthquake or when shaking a container to compact a powder. A large hole (1) is maintained by the particles sticking to each other. A small, counterclockwise strain (2) collapses the hole, and another large strain (3) forms more new holes which collapse when the strain reverses (4). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (after T.L. Youd, Packing Changes and Liquefaction Susceptibility, Journal of the Geotechnical Engieering Division, 103: GT8,918-922, 1977)(Credit: NASA/Marshall Space Flight Center.)(Credit: University of Colorado at Boulder).

  6. Microgravity

    NASA Image and Video Library

    1989-10-17

    An automobile lies crushed under the third story of this apartment building in the Marina District after the Oct. 17, 1989, Loma Prieta earthquake. The ground levels are no longer visible because of structural failure and sinking due to liquefaction. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: J.K. Nakata, U.S. Geological Survey.

  7. Microgravity

    NASA Image and Video Library

    2000-07-01

    Key persornel in the Mechanics of Granular Materials (MGM) experiment are Mark Lankton (Program Manager at University Colorado at Boulder), Susan Batiste (research assistance, UCB), and Stein Sture (principal investigator). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: University of Colorado at Boulder).

  8. Microgravity

    NASA Image and Video Library

    1989-10-17

    Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

  9. Microgravity

    NASA Image and Video Library

    1989-10-17

    Ground shaking triggered liquefaction in a subsurface layer of water-saturated sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and slit, which moved from right to left towards the Pajaro River. This mode of ground failure, termed lateral spreading, is a principal cause of liquefaction-related earthquake damage caused by the Oct. 17, 1989, Loma Prieta earthquake. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: S.D. Ellen, U.S. Geological Survey

  10. Microgravity

    NASA Image and Video Library

    1998-01-01

    On STS-89, three Mechanics of Granular Materials (MGM) test cells were subjected to five cycles of compression and relief (left) and three were subjected to shorter displacement cycles that simulate motion during an earthquake (right). In the compression/relief tests, the sand particles rearranged themselves and slightly re-expanded the column during relief. In the short displacement tests, the specimen's resistance to compression decreases, even though the displacement remains the same. The specimens were cycled up to 100 times or until the resistive force was less than 1% that of the previous cycle. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/Marshall Space Flight Center (MSFC)

  11. Microgravity

    NASA Image and Video Library

    2000-07-01

    Key persornel in the Mechanics of Granular Materials (MGM) experiment include Khalid Alshibli, project scientist at NASA's Marshall Space Flight Center (MSFC). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that cannot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: MSFC).

  12. Microgravity

    NASA Image and Video Library

    2001-10-04

    The Water Mist commercial research program is scheduled to fly an investigation on STS-107 in 2002. This investigation will be flown as an Experimental Mounting Structure (EMS) insert into the updated Combustion Module (CM-2), a sophisticated combustion chamber plus diagnostic equipment. (The investigation hardware is shown here mounted in a non-flight frame similar to the EMS.) Water Mist is a commercial research program by the Center for Commercial Applications of Combustion in Space (CCACS), a NASA Commercial Space Center located at the Colorado School of Mines, in Golden, CO and Industry Partner Environmental Engineering Concepts. The program is focused on developing water mist as a replacement for bromine-based chemical fire suppression agents (halons). By conducting the experiments in microgravity, interference from convection currents is minimized and fundamental knowledge can be gained. This knowledge is incorporated into models, which can be used to simulate a variety of physical environments. The immediate objective of the project is to study the effect of a fine water mist on a laminar propagating flame generated in a propane-air mixture at various equivalence ratios. The effects of droplet size and concentration on the speed of the flame front is used as a measure of the effectiveness of fire suppression in this highly controlled experimental environment.

  13. Vibration isolation technology development to demonstration

    NASA Technical Reports Server (NTRS)

    Grodsinsky, Carlos

    1992-01-01

    The main thrust of these studies has resulted in an active inertial feedforward/feedback isolation system. This prototype magnetic suspension system has been demonstrated in a laboratory setting in six degrees-of-freedom and has been preliminarily characterized in its isolation performance with favorable results. This isolation system consists of a closed loop digital control system referencing a platform around six relative and six inertial sensors. These sensors control the isolated mass through nine attractive electromagnetic actuators with a system capability of +/- three-tenths of an inch travel in three dimensions. The development of a prototype system from design to fabrication leads directly into the demonstration phase of the project which will attempt a low gravity environmental demonstration of engineering hardware for the isolation of a scientific payload. The demonstration phase of the project will use an aircraft low gravity maneuver to establish a research testbed for the study of isolation hardware and control strategies in an off-loaded environment. In developing this demonstration capability the Lewis Learjet aircraft has been characterized through its parabolic flight maneuvers and a trunnioned experimental volume has been designed for the test of both active and passive isolation packages. This vibration isolation testbed is operational and has two data acquisition systems available for both autonomous and interactive operation, with a combined input capability of 32 channels.

  14. Conceptual design methodology for vibration isolation

    NASA Astrophysics Data System (ADS)

    Hyde, T. Tupper

    1997-06-01

    High performance dynamic structures have strict requirements on structural motion that are emphasized by the flexibility inherent in lightweight space systems. Vibration isolation is used to prevent disturbances from affecting critical payload components where motion is to be minimized. Isolation, however, is often an engineering solution that is not properly considered in the early conceptual design of the spacecraft. It is at this key stage of a program that mission driving performance targets and resource allocations are made yet little analysis has been performed. A conceptual design methodology for isolation is developed and applied to the conceptual design of a proposed space shuttle based telescope system. In the developed methodology, frequency domain computation of the closed loop performance without isolation pinpoints frequency regimes and disturbance to performance channels targeted for improvement. A coarse fidelity structural model, with well defined disturbance and performance characterization, is more useful than a costly high fidelity analysis when evaluating the many isolation options available early in a project. Isolation design choices are made by trading their performance improvement against their complexity/cost. Simple, idealized mechanical descriptions of the passive or active isolation system provide the needed frequency domain effect on performance without the costly analysis that a detailed isolator design entails. Similarly, the effects of other integrating subsystems, such as structural or optical control are approximated by frequency domain descriptions.

  15. Electromechanical lever blocks for active vibration isolation

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.

    2000-04-01

    This paper is a follow-up of a presentation at the Smart Structures Symposium of 1998. There we described an innovative technical solution which provides a combined passive damping and isolation interface with the appropriate transmissibility characteristics between a vibrating base and a sensitive payload, typically an optical terminal/telescope. The particularity of the solution is primarily found in the implementation of energy dissipation by means linear electromagnetic linear motors leveraged by means of flexure elements, to constitute an integrated resistor-damped electromechanic lever block, which we called MEDI (Mechanical Elastic element for Damping and Isolation). Passive viscous damping with attenuation of the order of -20 dB at 50 Hz with respect to a hard fixation, is obtained by simply short- circuiting the electro-magnetic motor. The study and test program presented here extends the application of MEDIs to active vibration reduction systems. The study, contracted by the European Space Agency, aimed at investigating the possibility of using the MEDI as an active isolator for scientific experiments in the International Space Station. By controlling the current in the electromagnetic motor in closed loop with the signal from specially designed force sensor (with extremely low noise), we achieved attenuation of the order of -15 dB at 1 Hz, -30 dB at 10 Hz, -50 dB at 30 Hz, with the isolation slope starting as low as 0.1 Hz.

  16. Development of a launch vibration isolation system

    NASA Astrophysics Data System (ADS)

    Edberg, Donald L.; Johnson, Conor D.; Davis, L. Porter; Fosness, Eugene R.

    1997-05-01

    The U.S. Air Force's Phillips Laboratory has sponsored several programs to isolate payloads from mechanical vibrations during launch. This paper details a program called LVIS (for launch vibration isolation system). LVIS's goals are to reduce the rms accelerations felt by an isolated payload by a factor of 5 compared to an unisolated payload while using minimal launch vehicle services, fitting within existing payload attach fittings' dimension and mass envelopes, and providing fail- safe operation. The LVIS system must provide axial isolation while at the same time not allowing its host spacecraft to 'rattle' too much and make contact with the launch vehicle's external payload fairing, which is present to protect against heat, aerodynamic, and acoustic loads. This challenging set of goals will be accomplished using an innovative suspension system specially designed to be relatively soft in the vertical and lateral directions and stiff in the rotational directions to prevent payload fairing contact. An overview of the LVIS design and predicted performance is given.

  17. Active vibration isolation using decentralized velocity feedback control

    NASA Astrophysics Data System (ADS)

    Brennan, Michael J.; Elliott, Stephen J.; Huang, X.

    2003-03-01

    Isolating a piece of delicate equipment from the vibration of a base structure is of practical importance in a number of engineering fields. Examples are the isolation of instrument boxes in aeroplane and the isolation of telescopes and antennas in satellites. In the majority of cases, the base is flexible and vibrates with an upredictable waveform which has a broadband spectrum. The active isolation of a vibration-sensitive equipment structure from a vibrating base is studied in this paper. Passive anti-vibration mounts are widely used to support the equipment and protect it from severe base vibration. However, conventional passive mounts suffer from an inherent trade-off between high frequency isolation and amplification of vibration at the fundamental mounted resonance frequency. General the best isolation performance is achieved by using an active system in combination with a passive mount, where the fundamental resonance can be actively controlled without reducing the high frequency performance.

  18. Hybrid isolation of micro vibrations induced by reaction wheels

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Oen; Park, Geeyong; Han, Jae-Hung

    2016-02-01

    As the technology for precision satellite payloads continues to advance, the requirements for the pointing stability of the satellites are becoming extremely high. In many situations, even small amplitude disturbances generated by the onboard components may cause serious degradation in the performance of high precision payloads. In such situations, vibration isolators can be installed to reduce the vibration transmission. In this work, a hybrid vibration isolator comprising passive and active components is proposed to provide an effective solution to the vibration problems caused by the reaction wheel disturbances. Firstly, mathematical modeling and experimental study of a single axis vibration isolator having high damping and high roll-off rate for the high frequency region and active components that enhance isolation performance for narrow frequency bands are presented. This concept is then extended to multi-axis by forming Stewart platform and the performance is experimentally verified. The tests on a flexible testbed show effective vibration isolation by the proposed vibration isolator.

  19. Frequency-Weighting Filter Selection, for H2 Control of Microgravity Isolation Systems: A Consideration of the "Implicit Frequency Weighting" Problem

    NASA Technical Reports Server (NTRS)

    Hampton, Roy David; Whorton, Mark S.

    1999-01-01

    Many space-science experiments need an active isolation system to provide them with the requisite microgravity environment. The isolation systems planned for use with the International Space Station (ISS) have been appropriately modeled using relative position, relative velocity, and acceleration states. In theory, frequency-weighting design filters can be applied to these state-space models, in order to develop optimal H2 or mixed-norm controllers with desired stability and performance characteristics. In practice, however, since there is a kinematic relationship among the various states, any frequency weighting applied to one state will implicitly weight other states. These implicit frequency-weighting effects must be considered, for intelligent frequency-weighting filter assignment. This paper suggests a rational approach to the assignment of frequency-weighting design filters, in the presence of the kinematic coupling among states that exists in the microgravity vibration isolation problem.

  20. Microgravity

    NASA Image and Video Library

    2001-01-24

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of liquid xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Resembling a tiny bit of window screen, the oscillator at the heart of CVX-2 will vibrate between two pairs of paddle-like electrodes. The slight bend in the shape of the mesh has no effect on the data. What counts are the mesh's displacement in the xenon fluid and the rate at which the displacement dampens. The unit shown here is encased in a small test cell and capped with a sapphire windown to contain the xenon at high pressure.

  1. Active vibration isolation using smart structures

    NASA Technical Reports Server (NTRS)

    Guigou, C.; Wagstaff, P. R.; Fuller, C. R.

    1991-01-01

    Passive technologies for the isolation of structures from vibrating sources are often inadequate. Using active control inputs applied directly to the source or designing a structure integrating the transducers required for the control inputs and the response measurements are ways of dealing with the problem. Results are given which were obtained on an experimental set up simulating this kind of problem where the form and the position of the transducers could be varied. By measuring the response of the structure integrated over a particular area the effects of particular types of modes could be taken into account to deal with specific types of input or limit particular modes of response more efficiently. Results of using different modes of vibration excitation of the receiving structure with and without control are presented for particular input frequencies. The problems of optimizing the control system to deal with multiple frequency inputs are discussed.

  2. Temperature field in rubber vibration isolators

    NASA Astrophysics Data System (ADS)

    Abdulhadi, M. Issa

    1985-02-01

    The temperature field inside a vibrating rubber solid cylinder is investigated. The rubber cylinder, a specimen of a vibration isolator rubber (Neoprene GR), is subjected to a repeatedly cyclic compressive force by means of an electrodynamic shaker. In the experimental investigation the temperatures at 16 different locations inside the cylinder have been measured by means of copper-constantan thermocouples. After the estimation of the heat generated per unit volume per unit time with the help of the estimated damping and stiffness coefficients of rubber, one can attempt the solution of the heat conduction equation describing the temperature field inside the rubber specimen. The values of the temperature found from the analytical investigation compare fairly well with the experimental measurements.

  3. Microgravity

    NASA Image and Video Library

    1998-10-10

    Isolation of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue. Isolate of long-term growth human mammary epithelial cells (HMEC) from outgrowth of duct element; cells shown soon after isolation and early in culture in a dish. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Robert Tichmond, NASA/Marshall Space Flight Center (MSFC).

  4. Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station

    NASA Technical Reports Server (NTRS)

    McCrory, Jean L.; Lemmon, David R.; Sommer, H. Joseph; Prout, Brian; Smith, Damon; Korth, Deborah W.; Lucero, Javier; Greenisen, Michael; Moore, Jim

    1999-01-01

    A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 deg, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

  5. Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for use on the International Space Station.

    PubMed

    McCrory, J L; Lemmon, D R; Sommer, H J; Prout, B; Smith, D; Korth, D W; Lucero, J; Greenisen, M; Moore, J; Kozlovskaya, I; Pestov, I; Stepansov, V; Miyakinchenko, Y; Cavanagh, P R

    1999-08-01

    A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 degrees, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

  6. Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station

    NASA Technical Reports Server (NTRS)

    McCrory, Jean L.; Lemmon, David R.; Sommer, H. Joseph; Prout, Brian; Smith, Damon; Korth, Deborah W.; Lucero, Javier; Greenisen, Michael; Moore, Jim

    1999-01-01

    A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak linear and angular displacements of less than 2.5 cm and 2.5 deg, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.

  7. Microgravity

    NASA Image and Video Library

    1989-02-03

    (PCG) Protein Crystal Growth Canavalin. The major storage protein of leguminous plants and a major source of dietary protein for humans and domestic animals. It is studied in efforts to enhance nutritional value of proteins through protein engineerings. It is isolated from Jack Bean because of it's potential as a nutritional substance. Principal Investigator on STS-26 was Alex McPherson.

  8. Microgravity

    NASA Image and Video Library

    1993-04-29

    The major storage protein of leguminous plants and a major source of dietary protein for humans and domestic animals. It is studied in efforts to enhance nutritional value of proteins through protein engineerings. It is isolated from Jack Bean because of it's potential as a nutritional substance. Principal Investigator was Alexander McPherson.

  9. Miniature vibration isolation system for space applications

    NASA Astrophysics Data System (ADS)

    Quenon, Dan; Boyd, Jim; Buchele, Paul; Self, Rick; Davis, Torey; Hintz, Timothy L.; Jacobs, Jack H.

    2001-06-01

    In recent years, there has been a significant interest in, and move towards using highly sensitive, precision payloads on space vehicles. In order to perform tasks such as communicating at extremely high data rates between satellites using laser cross-links, or searching for new planets in distant solar systems using sparse aperture optical elements, a satellite bus and its payload must remain relatively motionless. The ability to hold a precision payload steady is complicated by disturbances from reaction wheels, control moment gyroscopes, solar array drives, stepper motors, and other devices. Because every satellite is essentially unique in its construction, isolating or damping unwanted vibrations usually requires a robust system over a wide bandwidth. The disadvantage of these systems is that they typically are not retrofittable and not tunable to changes in payload size or inertias. Previous work, funded by AFRL, DARPA, BMDO and others, developed technology building blocks that provide new methods to control vibrations of spacecraft. The technology of smart materials enables an unprecedented level of integration of sensors, actuators, and structures; this integration provides the opportunity for new structural designs that can adaptively influence their surrounding environment. To date, several demonstrations have been conducted to mature these technologies. Making use of recent advances in smart materials, microelectronics, Micro-Electro Mechanical Systems (MEMS) sensors, and Multi-Functional Structures (MFS), the Air Force Research Laboratory along with its partner DARPA, have initiated an aggressive program to develop a Miniature Vibration Isolation System (MVIS) (patent pending) for space applications. The MVIS program is a systems-level demonstration of the application of advanced smart materials and structures technology that will enable programmable and retrofittable vibration control of spacecraft precision payloads. The current effort has been awarded

  10. The isolation limits of stochastic vibration

    NASA Technical Reports Server (NTRS)

    Knopse, C. R.; Allaire, P. E.

    1993-01-01

    The vibration isolation problem is formulated as a 1D kinematic problem. The geometry of the stochastic wall trajectories arising from the stroke constraint is defined in terms of their significant extrema. An optimal control solution for the minimum acceleration return path determines a lower bound on platform mean square acceleration. This bound is expressed in terms of the probability density function on the significant maxima and the conditional fourth moment of the first passage time inverse. The first of these is found analytically while the second is found using a Monte Carlo simulation. The rms acceleration lower bound as a function of available space is then determined through numerical quadrature.

  11. Microgravity

    NASA Image and Video Library

    1998-10-10

    Isolation of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue; A: Duct element recovered from breast tissue digest. B: Outgrowth of cells from duct element in upper right corner cultured in a standard dish; most cells spontaneousely die during early cell divisions, but a few will establish long-term growth. C: Isolate of long-term frowth HMEC from outgrowth of duct element; cells shown soon after isolation and in early full-cell contact growth in culture in a dish. D: same long-term growth HMEC, but after 3 weeks in late full-cell contact growth in a continuous culture in a dish. Note attempts to reform duct elements but this in two demensions in a dish rather than in three dimensions in tissue. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Robert Richmond, NASA/Marshall Space Flight Center (MSFC).

  12. Optimization design of vibration characteristics of ship composite brace with rigid vibration isolation mass

    NASA Astrophysics Data System (ADS)

    Wang, Qiangyong; Yao, Xiongliang; Yu, Danzhu; Pang, Fuzhen

    2011-06-01

    In considering the theory of structural dynamic optimization design, a design method of the structural style of ship composite brace with rigid vibration isolation mass was studied. Two kinds of structural dynamic optimization formulations minimizing the vibration acceleration of the non-pressure hull on the restraining condition of the gross weight of the ship cabin were established: 1) dynamic optimization of the sectional dimensions of the rigid vibration isolation mass in the composite brace; 2) dynamic optimization of the arranging position of the rigid vibration isolation mass. Through the optimization results, sectional dimensions and the arranging position of the rigid vibration isolation mass with better performance in reducing vibration were gained, and some reference was provided for practical engineering designs as well as enrichment of the design method of a novel ship vibration-isolation brace.

  13. Microgravity

    NASA Image and Video Library

    1998-10-01

    The ADvanced SEParation (ADSEP) commercial payload is making use of major advances in separation technology: The Phase Partitioning Experiment (PPE); the Micorencapsulation experiment; and the Hemoglobin Separation Experiment (HSE). Using ADSEP, commercial researchers will attempt to determine the partition coefficients for model particles in a two-phase system. With this information, researchers can develop a higher resolution, more effective cell isolation procedure that can be used for many different types of research and for improved health care. The advanced separation technology is already being made available for use in ground-based laboratories.

  14. NIST torsion oscillator viscometer response: Performance on the LeRC active vibration isolation platform

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Grodsinsky, Carlos M.

    1992-01-01

    Critical point viscosity measurements are limited to their reduced temperature approach to T(sub c) in an Earth bound system, because of density gradients imposed by gravity. Therefore, these classes of experiments have been proposed as good candidates for 'microgravity' science experiments where this limitation is not present. The nature of these viscosity measurements dictate hardware that is sensitive to low frequency excitations. Because of the vibratory acceleration sensitivity of a torsion oscillator viscometer, used to acquire such measurements, a vibration isolation sensitivity test was performed on candidate 'microgravity' hardware to study the possibility of meeting the stringent oscillatory sensitivity requirements of a National Institute of Standards and Technology (NIST) torsion oscillator viscometer. A prototype six degree of freedom active magnetic isolation system, developed at NASA Lewis Research Center, was used as the isolation system. The ambient acceleration levels of the platform were reduced to the noise floor levels of its control sensors, about one microgravity in the 0.1 to 10 Hz bandwidth.

  15. Microgravity

    NASA Image and Video Library

    1998-10-10

    Isolation of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue. Same long-term growth human mammary epithelial cells (HMEC), but after 3 weeks in concinuous culture. Note attempts to reform duct elements, but this time in two dimensions in a dish rather that in three demensions in tissue. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Robert Tichmond, NASA/Marshall Space Flight Center (MSFC).

  16. Microgravity

    NASA Image and Video Library

    1998-10-10

    Isolation of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue. Outgrowth of cells from duct element in upper right corner cultured in a standard dish; most cells spontaneously die during early cell divisions, but a few will establish long-term growth. NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cell (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunorous tissue. Credit: Dr. Robert Tichmond, NASA/Marshall Space Flight Center (MSFC).

  17. The thermo-vibrational convection in microgravity condition. Ground-based modelling.

    NASA Astrophysics Data System (ADS)

    Zyuzgin, A. V.; Putin, G. F.; Harisov, A. F.

    In 1995-2000 at orbital station "Mir" has been carried out the series of experiments with the equipment "Alice" for the studying regimes of heat transfer in the supercritical fluids under influence inertial microaccelerations. The experiments have found out existence of the thermo-vibrational and thermo-inertial convective movements in the real weightlessness[1] and controlling microgravity fields[2]. However regarding structures of thermovibrational convection the results of experiments have inconsistent character. Therefore carrying out the ground-based modeling of the given problem is actually. In this work in laboratory conditions were investigated the thermo-vibrational convective movements from the dot heat source at high-frequency vibrations of the cavity with the fluid and presence quasi-static microacceleration. As the result of ground-based modeling, the regimes of convective flows, similar observed in the space experiment are received. Evolution of the convective structures and the spatial-temporary characteristics of movements are investigated in a wide range of the problem parameters. The control criteria and its critical value are determined. The received results well coordinated to the data of space experiments and allow adding and expanding representation about thermo-vibrational effects in conditions of real weightlessness and remove the contradictions concerning structures thermo-vibrational convective flows, received at the analysis of the given orbital experiments. The research described in this publication was made possible in part by Russian Foundation for Basic Research and Administration of Perm Region, Russia, under grant 04-02-96038, and Award No. PE-009-0 of the U.S. Civilian Research & Development Foundation for the Independent States of the Former Soviet Union (CRDF). A.V. Zyuzgin, A. I. Ivanov, V. I. Polezhaev, G. F. Putin, E. B. Soboleva Convective Motions in Near-Critical Fluids under Real Zero-Gravity Conditions. Cosmic Research

  18. Active vibration isolation based on model reference adaptive control

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Kiong Tan, Kok; Guo, Yu; Cong, Ming; Lee, Tong Heng

    2014-02-01

    High-performance instruments are very sensitive to vibrations and jitters. In this article, a new approach towards multi-degree-of-freedom (DOF) active vibration isolation and its application in spacecraft jitter suppression are presented. Model reference adaptive control (MRAC) with acceleration feedback is used to isolate random disturbances. However, a side effect of this algorithm is that displacements at low frequencies are amplified. Thus, the MRAC is augmented with proportional-integral-differential (PID) displacement feedback to suppress vibration displacements. The MRAC-PID composite control is applied to a 4-leg platform to isolate vibrations and suppress tip/tilt jitters. The scheme is also used to isolate 6-DOF vibrations and steer the payload of a flexible spacecraft. Satisfactory performance of vibration isolation and jitter attenuation has been observed.

  19. Microgravity

    NASA Image and Video Library

    2001-01-24

    This photo shows an individual cell from the Handheld Diffusion Test Cell (HH-DTC) apparatus flown on the Space Shuttle. Similar cells will be used in the Observable Protein Crystal Growth Apparatus (OPCGA) to be operated aboard the International Space Station (ISS). The principal investigator is Dr. Alex McPherson of the University of California, Irvine. Each individual cell comprises two sample chambers with a rotating center section that isolates the two from each other until the start of the experiment and after it is completed. The cells are made from optical-quality quartz glass to allow photography and interferometric observations. Each cell has a small light-emitting diode and lens to back-light the solution. In protein crystal growth experiments, a precipitating agent such as a salt solution is used to absorb and hold water but repel the protein molecules. This increases the concentration of protein until the molecules nucleate to form crystals. This cell is one of 96 that make up the experiment module portion of the OPCGA.

  20. Microgravity

    NASA Image and Video Library

    2001-01-24

    This photo shows the Handheld Diffusion Test Cell (HH-DTC) apparatus flown on the Space Shuttle. Similar cells (inside the plastic box) will be used in the Observable Protein Crystal Growth Apparatus (OPCGA) to be operated aboard the International Space Station (ISS). The principal investigator is Dr. Alex McPherson of the University of California, Irvine. Each individual cell comprises two sample chambers with a rotating center section that isolates the two from each other until the start of the experiment and after it is completed. The cells are made from optical-quality quartz glass to allow photography and interferometric observations. Each cell has a small light-emitting diode and lens to back-light the solution. In protein crystal growth experiments, a precipitating agent such as a salt solution is used to absorb and hold water but repel the protein molecules. This increases the concentration of protein until the molecules nucleate to form crystals. This cell is one of 96 that make up the experiment module portion of the OPCGA.

  1. Utilizing Controlled Vibrations in a Microgravity Environment to Understand and Promote Microstructural Homogeneity During Floating-Zone Crystal Growth

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.

    1999-01-01

    It has been demonstrated in floating-zone configurations utilizing silicone oil and nitrate salts that mechanically induced vibration effectively minimizes detrimental, gravity independent, thermocapillary flow. The processing parameters leading to crystal improvement and aspects of the on-going modeling effort are discussed. Plans for applying the crystal growth technique to commercially relevant materials, e.g., silicon, as well as the value of processing in a microgravity environment are presented.

  2. Microgravity

    NASA Image and Video Library

    2001-05-15

    Lisa Freed and Gordana Vunjak-Novakovic, both of the Massachusetts Institute of Technology (MIT), have taken the first steps toward engineering heart muscle tissue that could one day be used to patch damaged human hearts. Cells isolated from very young animals are attached to a three-dimensional polymer scaffold, then placed in a NASA bioreactor. The cells do not divide, but after about a week start to cornect to form a functional piece of tissue. Here, a transmission electron micrograph of engineered tissue shows a number of important landmarks present in functional heart tissue: (A) well-organized myofilaments (Mfl), z-lines (Z), and abundant glycogen granules (Gly); and (D) intercalcated disc (ID) and desmosomes (DES). The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). Credit: MIT

  3. Microgravity

    NASA Image and Video Library

    2001-05-15

    Lisa Freed and Gordana Vunjak-Novakovic, both of the Massachusetts Institute of Technology (MIT), have taken the first steps toward engineering heart muscle tissue that could one day be used to patch damaged human hearts. Cells isolated from very young animals are attached to a three-dimensional polymer scaffold, then placed in a NASA bioreactor. The cells do not divide, but after about a week start to cornect to form a functional piece of tissue. Functionally connected heart cells that are capable of transmitting electrical signals are the goal for Freed and Vunjak-Novakovic. Electrophysiological recordings of engineered tissue show spontaneous contractions at a rate of 70 beats per minute (a), and paced contractions at rates of 80, 150, and 200 beats per minute respectively (b, c, and d). The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). Credit: NASA and MIT.

  4. Design of a Long-Stroke Noncontact Electromagnetic Actuator for Active Vibration Isolation

    NASA Technical Reports Server (NTRS)

    Banerjee, Bibhuti; Allaire, Paul E.

    1996-01-01

    A long-stroke moving coil Lorentz Actuator was designed for use in a microgravity vibration isolation experiment. The final design had a stroke of 5.08 cm (2 in) and enough force capability to isolate a mass of the order of 22.7-45.4 kg. A simple dynamic magnetic circuit analysis, using an electrical analog, was developed for the initial design of the actuator. A neodymium-iron-boron material with energy density of 278 T-kA/m (35 MGOe) was selected to supply the magnetic field. The effect of changes in the design parameters of core diameter, shell outer diameter, pole face length, and coil wire layers were investigated. An extensive three-dimensional finite element analysis was carried out to accurately determine linearity with regard to axial position of the coil and coil current levels. The actuator was constructed and tested on a universal testing machine. Example plots are shown, indicating good linearity over the stroke of approximately 5.08 cm (2 in) and a range of coil currents from -1.5 A to +1.5 A. The actuator was then used for the microgravity vibration isolation experiments, described elsewhere.

  5. A new isolator for vibration control

    NASA Astrophysics Data System (ADS)

    Behrooz, Majid; Sutrisno, Joko; Wang, Xiaojie; Fyda, Robert; Fuchs, Alan; Gordaninejad, Faramarz

    2011-03-01

    This study presents the feasibility of a new variable stiffness and damping isolator (VSDI) in an integrated vibratory system. The integrated system comprised of two VSDIs, a connecting plate and a mass. The proposed VSDI consists of a traditional steel-rubber vibration absorber, as the passive element, and a magneto-rheological elastomer (MRE), with a controllable (or variable) stiffness and damping, as the semi-active element. MREs' stiffness and damping properties can be altered by a magnetic field. Dynamic testing on this integrated system has been performed to investigate the effectiveness of the VSDIs for vibration control. Experimental results show significant shift in natural frequency, when activating the VSDIs. Transmissibility and natural frequency of the integrated system are obtained from properties of single device. The experimental and predicted results show good agreement between the values of the natural frequency of the system at both off and on states. However, system damping predictions are different from experimental results. This might be due to unforeseen effects of pre-stressed MREs and nonlinear material properties.

  6. Systematic analyses of vibration noise of a vibration isolation system for high-resolution scanning tunneling microscopes.

    PubMed

    Iwaya, Katsuya; Shimizu, Ryota; Hashizume, Tomihiro; Hitosugi, Taro

    2011-08-01

    We designed and constructed an effective vibration isolation system for stable scanning tunneling microscopy measurements using a separate foundation and two vibration isolation stages (i.e., a combination of passive and active vibration isolation dampers). Systematic analyses of vibration data along the horizontal and vertical directions are present, including the vibration transfer functions of each stage and the overall vibration isolation system. To demonstrate the performance of the system, tunneling current noise measurements are conducted with and without the vibration isolation. Combining passive and active vibration isolation dampers successfully removes most of the vibration noise in the tunneling current up to 100 Hz. These comprehensive vibration noise data, along with details of the entire system, can be used to establish a clear guideline for building an effective vibration isolation system for various scanning probe microscopes and electron microscopes.

  7. Low vibration laboratory with a single-stage vibration isolation for microscopy applications.

    PubMed

    Voigtländer, Bert; Coenen, Peter; Cherepanov, Vasily; Borgens, Peter; Duden, Thomas; Tautz, F Stefan

    2017-02-01

    The construction and the vibrational performance of a low vibration laboratory for microscopy applications comprising a 100 ton floating foundation supported by passive pneumatic isolators (air springs), which rest themselves on a 200 ton solid base plate, are discussed. The optimization of the air spring system leads to a vibration level on the floating floor below that induced by an acceleration of 10 ng for most frequencies. Additional acoustic and electromagnetic isolation is accomplished by a room-in-room concept.

  8. Low vibration laboratory with a single-stage vibration isolation for microscopy applications

    NASA Astrophysics Data System (ADS)

    Voigtländer, Bert; Coenen, Peter; Cherepanov, Vasily; Borgens, Peter; Duden, Thomas; Tautz, F. Stefan

    2017-02-01

    The construction and the vibrational performance of a low vibration laboratory for microscopy applications comprising a 100 ton floating foundation supported by passive pneumatic isolators (air springs), which rest themselves on a 200 ton solid base plate, are discussed. The optimization of the air spring system leads to a vibration level on the floating floor below that induced by an acceleration of 10 ng for most frequencies. Additional acoustic and electromagnetic isolation is accomplished by a room-in-room concept.

  9. A micromachined vibration isolation system for reducing the vibration sensitivity of surface transverse wave resonators.

    PubMed

    Reid, J R; Bright, V M; Kosinski, J A

    1998-01-01

    A micromachined system has been developed for reducing the vibration sensitivity of surface transverse wave (STW) resonators. The isolation system consists of a support platform for mounting the STW resonator, four support arms, and a support rim. The entire isolation system measures 8 mm by 9 mm by 0.4 mm without the resonator mounted on the platform. The system acts as a passive vibration isolation system, decreasing the magnitude of high frequency (>1.2 kHz) vibrations. Finite element analysis is used to analyze the acceleration sensitivity of the mounted resonator. The isolation system is then modeled as a damped mass-spring system and the transmissibility of vibration from the support rim to the support platform is calculated. Multiplying the acceleration sensitivity of the resonator by the transmissibility results in the expected system vibration sensitivity. The isolation systems are fabricated using two sided bulk etching of (110) oriented silicon wafers. STW resonators were mounted on the isolation systems, and the isolated units were mounted on commercial hybrid oscillator substrates. Vibration sensitivity measurements were taken for vibrations with frequencies ranging from 100 Hz to 5 kHz. The measured data show that the system performs as expected with a low frequency (<500 Hz) vibration sensitivity of 1.8x10(-8)/g and a high frequency roll off of 12 dB/octave.

  10. Integrated Design Of Space Telescope Vibration isolation And Attitude Control

    NASA Astrophysics Data System (ADS)

    Guan, Xin; Zheng, Gangtie

    2012-07-01

    An integrated design methodology for telescope vibration isolation and attitude control is proposed and demonstrated through an example problem. It is shown that ultra-low frequency vibration isolation can be realized without significantly degrade the control performance with the integrated design method. It is also shown that although active damping can be added to the flexible mode through proper control algorithm modification, passive damping of isolator is still important to the control system performance by improving the stability margin and robustness.

  11. Vibration isolation via a scissor-like structured platform

    NASA Astrophysics Data System (ADS)

    Sun, Xiuting; Jing, Xingjian; Xu, Jian; Cheng, Li

    2014-04-01

    More and more attentions are attracted to the analysis and design of nonlinear vibration control/isolation systems for better isolation performance. In this study, an isolation platform with n-layer scissor-like truss structure is investigated to explore novel design of passive/semi-active/active vibration control/isolation systems and to exploit potential nonlinear benefits in vibration suppression. Due to the special scissor-like structure, the dynamic response of the platform has inherent nonlinearities both in equivalent damping and stiffness characteristics (although only linear components are applied), and demonstrates good loading capacity and excellent equilibrium stability. With the mathematical modeling and analysis of the equivalent stiffness and damping of the system, it is shown that: (a) the structural nonlinearity in the system is very helpful in vibration isolation, (b) both equivalent stiffness and damping characteristics are nonlinear and could be designed/adjusted to a desired nonlinearity by tuning structural parameters, and (c) superior vibration isolation performances (e.g., quasi-zero stiffness characteristics etc.) can be achieved with different structural parameters. This scissor-like truss structure can potentially be employed in different engineering practices for much better vibration isolation or control.

  12. Wakata on Cycle Ergometer with Vibration Isolation System (CEVIS)

    NASA Image and Video Library

    2009-03-30

    ISS018-E-043723 (30 March 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 18/19 flight engineer, exercises on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station.

  13. Fincke uses Cycle Ergometer with Vibration Isolation System (CEVIS)

    NASA Image and Video Library

    2009-03-26

    ISS018-E-043414 (26 March 2009) --- Astronaut Michael Fincke, Expedition 18 commander, exercises on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station.

  14. Vibration isolation for line of sight performance improvement

    NASA Technical Reports Server (NTRS)

    Rodden, J. J.; Dougherty, H. J.; Haile, W. B.

    1987-01-01

    Diagrams of the Reaction Wheel Assembly (RWA) are presented along with charts and graphs illustrating jitter error model, induced vibration tests, radial displacement transfer function, and axial displacement power spectra density. The RWA isolator specification requirements are listed.

  15. Active vibration isolation platform on base of magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Mikhailov, Valery P.; Bazinenkov, Alexey M.

    2017-06-01

    The article describes the active vibration isolation platform on base of magnetorheological (MR) elastomers. An active damper based on the MR elastomers can be used as an actuator of micro- or nanopositioning for a vibroinsulated object. The MR elastomers give such advantages for active control of vibration as large range of displacements (up to 1 mm), more efficient absorption of the vibration energy, possibility of active control of amplitude-frequency characteristics and positioning with millisecond response speed and nanometer running accuracy. The article presents the results of experimental studies of the most important active damper parameters. Those are starting current, transient time for stepping, transmission coefficient of the vibration displacement amplitude.

  16. Evaluation of techniques for performing cellular isolation and preservation during microgravity conditions.

    PubMed

    Rizzardi, Lindsay F; Kunz, Hawley; Rubins, Kathleen; Chouker, Alexander; Quiriarte, Heather; Sams, Clarence; Crucian, Brian E; Feinberg, Andrew P

    2016-01-01

    Genomic and epigenomic studies require the precise transfer of microliter volumes among different types of tubes in order to purify DNA, RNA, or protein from biological samples and subsequently perform analyses of DNA methylation, RNA expression, and chromatin modifications on a genome-wide scale. Epigenomic and transcriptional analyses of human blood cells, for example, require separation of purified cell types to avoid confounding contributions of altered cellular proportions, and long-term preservation of these cells requires their isolation and transfer into appropriate freezing media. There are currently no protocols for these cellular isolation procedures on the International Space Station (ISS). Currently human blood samples are either frozen as mixed cell populations (within the CPT collection tubes) with poor yield of viable cells required for cell-type isolations, or returned under ambient conditions, which requires timing with Soyuz missions. Here we evaluate the feasibility of translating terrestrial cell purification techniques to the ISS. Our evaluations were performed in microgravity conditions during parabolic atmospheric flight. The pipetting of open liquids in microgravity was evaluated using analog-blood fluids and several types of pipette hardware. The best-performing pipettors were used to evaluate the pipetting steps required for peripheral blood mononuclear cell (PBMC) isolation following terrestrial density-gradient centrifugation. Evaluation of actual blood products was performed for both the overlay of diluted blood, and the transfer of isolated PBMCs. We also validated magnetic purification of cells. We found that positive-displacement pipettors avoided air bubbles, and the tips allowed the strong surface tension of water, glycerol, and blood to maintain a patent meniscus and withstand robust pipetting in microgravity. These procedures will greatly increase the breadth of research that can be performed on board the ISS, and allow

  17. Evaluation of techniques for performing cellular isolation and preservation during microgravity conditions

    PubMed Central

    Rizzardi, Lindsay F; Kunz, Hawley; Rubins, Kathleen; Chouker, Alexander; Quiriarte, Heather; Sams, Clarence; Crucian, Brian E; Feinberg, Andrew P

    2016-01-01

    Genomic and epigenomic studies require the precise transfer of microliter volumes among different types of tubes in order to purify DNA, RNA, or protein from biological samples and subsequently perform analyses of DNA methylation, RNA expression, and chromatin modifications on a genome-wide scale. Epigenomic and transcriptional analyses of human blood cells, for example, require separation of purified cell types to avoid confounding contributions of altered cellular proportions, and long-term preservation of these cells requires their isolation and transfer into appropriate freezing media. There are currently no protocols for these cellular isolation procedures on the International Space Station (ISS). Currently human blood samples are either frozen as mixed cell populations (within the CPT collection tubes) with poor yield of viable cells required for cell-type isolations, or returned under ambient conditions, which requires timing with Soyuz missions. Here we evaluate the feasibility of translating terrestrial cell purification techniques to the ISS. Our evaluations were performed in microgravity conditions during parabolic atmospheric flight. The pipetting of open liquids in microgravity was evaluated using analog-blood fluids and several types of pipette hardware. The best-performing pipettors were used to evaluate the pipetting steps required for peripheral blood mononuclear cell (PBMC) isolation following terrestrial density-gradient centrifugation. Evaluation of actual blood products was performed for both the overlay of diluted blood, and the transfer of isolated PBMCs. We also validated magnetic purification of cells. We found that positive-displacement pipettors avoided air bubbles, and the tips allowed the strong surface tension of water, glycerol, and blood to maintain a patent meniscus and withstand robust pipetting in microgravity. These procedures will greatly increase the breadth of research that can be performed on board the ISS, and allow

  18. New inertial actuator provides isolation and stabilization in microgravity conditions

    NASA Technical Reports Server (NTRS)

    Blackburn, John

    1992-01-01

    Experiments in materials and fluids processing have been conducted, or are planned, that take advantage of the low-g environment offered by space-based platforms. While the specific goals of the experiments vary, a common objective is to see improved results from the processes over those that would be obtained from similar ground-based experiments. While the space-based processing environment does offer a low-g environment, it is not disturbance free. Results of experiments already conducted, particularly those in manned vehicles, show that spacecraft induced disturbances still limit what can be achieved in materials processing. The duration of actual micro-g level environments is shorter than desired and periods of milli-g activity levels are not uncommon. While small scale experiments can be configured to overcome some of the vehicle disturbance sources, larger scale processing devices and commercial activities will require alternative methods to reduce the influences of spacecraft vibrations. Applied Technology Associates, Inc., (ATA), in cooperation with NASA Lewis Research Center, is developing hardware to provide a sustained micro-g experiment environment. This work is being sponsored under a Small Business Innovation Research (SBIR) program, which is currently in the Phase 2 development stage. ATA's approach is based on an inertial actuator, which when used as part of a closed-loop stabilization system, rejects unwanted disturbances to the experiment package. A prototype of the actuator has been fabricated and used in a laboratory demonstration to prove the principle of operation. ATA's presentation emphasized the development and testing of the Digital Materials Processing Experiment (DAMPER) inertial actuator. Physical and performance characteristics of the device are presented. Technical issues, including further optimization of the actuator's performance and plans for additional laboratory experiments, are also covered.

  19. Effect of simulated microgravity on growth and production of exopolymeric substances of Micrococcus luteus space and earth isolates.

    PubMed

    Mauclaire, Laurie; Egli, Marcel

    2010-08-01

    Microorganisms tend to form biofilms on surfaces, thereby causing deterioration of the underlaying material. In addition, biofilm is a potential health risk to humans. Therefore, microorganism growth is not only an issue on Earth but also in manned space habitats like the International Space Station (ISS). The aim of the study was to identify physiological processes relevant for Micrococcus luteus attachment under microgravity conditions. The results demonstrate that simulated microgravity influences physiological processes which trigger bacterial attachment and biofilm formation. The ISS strains produced larger amounts of exopolymeric substances (EPS) compared with a reference strain from Earth. In contrast, M. luteus strains were growing faster, and Earth as well as ISS isolates produced a higher yield of biomass under microgravity conditions than under normal gravity. Furthermore, microgravity caused a reduction of the colloidal EPS production of ISS isolates in comparison with normal gravity, which probably influences biofilm thickness and stability as well.

  20. Damping phenomena in a wire rope vibration isolation system

    NASA Technical Reports Server (NTRS)

    Tinker, M. L.; Cutchins, M. A.

    1992-01-01

    A study is presented of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators, with emphasis placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase plane trajectories, and frequency response curves are obtained. A semiempirical model having nonlinear stiffness, nth-power velocity damping, and variable Coulomb friction damping is developed, and the results are compared to experimental data. Several observations and conclusions are made about the dynamic phenomena in a typical wire rope vibration isolation system based on the experimental and semiempirical results.

  1. Active vibration isolation with a dielectric elastomer stack actuator

    NASA Astrophysics Data System (ADS)

    Kaal, William; Bartel, Torsten; Herold, Sven

    2017-05-01

    This work presents the development, simulation and experimental investigation of a demonstrator for active vibration isolation with dielectric elastomers (DEs). The electromechanical behavior of the developed DE stack actuator is first characterized experimentally and a suitable simulation model is parametrized accordingly. The potential of the actuator for active vibration isolation is shown in a specially designed single axis test rig. The influence of different control strategies on the transmission behavior from the excited base to the mass is studied. A special aspect of the control strategy is the compensation of the specific nonlinearities. The analysis proves the potential of DE actuators for active vibration isolation purposes. The presented broadband active isolation could enable the use of DEs in various technical fields of application.

  2. Identification of nonlinear anti-vibration isolator properties

    NASA Astrophysics Data System (ADS)

    Mezghani, Fares; Del Rincón, Alfonso Fernández; Souf, Mohamed Amine Ben; Fernandez, Pablo García; Chaari, Fakher; Viadero Rueda, Fernando; Haddar, Mohamed

    2017-06-01

    Vibrations are classified among the major problems for engineering structures. Anti-vibration isolators are used to absorb vibration energy and minimise transmitted force which can cause damage. The isolator is modelled as a parallel combination of stiffness and damping elements. The main purpose of the model is to enable designers to predict the dynamic response of systems under different structural excitations and boundary conditions. A nonlinear identification method, discussed in this paper, aims to provide a tool for engineers to extract information about the nonlinear dynamic behaviour using measured data from experiments. The proposed method is demonstrated and validated with numerical simulations. Thus, this technique is applied to determine the nonlinear parameters of a commercial metal mesh isolator. Nonlinear stiffness and nonlinear damping can decrease with the increase in the amplitude of the base excitation. The softening behaviour of the mesh isolator is clearly visible.

  3. A Study on Vibration Isolator for Reaction Wheel Assembly

    NASA Astrophysics Data System (ADS)

    Hatsutori, Yoichi; Nakasuka, Shinichi

    Reaction wheel assembly used as main actuator of an attitude control system can be a major source of disturbances. Although vibration isolator for a reaction wheel assembly is required to attenuate a disturbance, a control torque has to be transmitted for an attitude control of a satellite. This paper introduces a new design method of vibration isolator for reaction wheel assembly. Proposed method is based on H-infinity formulation and optimizes not only parameters of vibration isolator, but also parameters of satellite's controller simultaneously. At first, numerical model of a parallel link isolator is formulated. Next, the formulations of new design method and constraint conditions are described. After that, results of numerical analysis and availability of proposed method are shown.

  4. Vibration isolation and pressure compensation apparatus for sensitive instrumentation

    NASA Technical Reports Server (NTRS)

    Averill, R. D. (Inventor)

    1983-01-01

    A system for attenuating the inherent vibration associated with a mechanical refrigeration unit employed to cryogenically cool sensitive instruments used in measuring chemical constituents of the atmosphere is described. A modular system including an instrument housing and a reaction bracket with a refrigerator unit floated there between comprise the instrumentation system. A pair of evacuated bellows that "float' refrigerator unit and provide pressure compensation at all levels of pressure from seal level to the vacuum of space. Vibration isolators and when needed provide additional vibration damping for the refrigerator unit. A flexible thermal strap (20 K) serves to provide essentially vibration free thermal contact between cold tip of the refrigerator unit and the instrument component mounted on the IDL mount. Another flexible strap (77 K) serves to provide vibration free thermal contact between the TDL mount thermal shroud and a thermal shroud disposed about the thermal shaft.

  5. A torsion quasi-zero stiffness vibration isolator

    NASA Astrophysics Data System (ADS)

    Zhou, Jiaxi; Xu, Daolin; Bishop, Steven

    2015-03-01

    A torsion vibration isolator with quasi-zero stiffness (QZS) is proposed to attenuate the transmission of torsional vibration along a shaft system, which also plays a role of coupling between shafts. A pre-compressed cam-roller mechanism is designed to provide torsional negative stiffness that counteracts with the positive torsion stiffness of the vulcanized rubber between shafts. With the design parameters are set to satisfy a unique condition, the stiffness of the isolator delivers a QZS property about the equilibrium position. A nonlinear mathematical model is developed and its dynamic characteristics are further analyzed by using the Harmonic Balance method. A typical folded resonance curve occurs when the vibration amplitude is plotted as the excitation frequency is varied, illustrating a jump phenomenon in the response. The efficiency of vibration attenuation is estimated under a designed torque load, showing that the torsion QZS vibration isolator outperforms the corresponding linear counterpart, especial in low frequency ranges. Furthermore, the torque transmissibility of the QZS isolator is also studied to demonstrate the performance of the QZS isolator when the actual torque deviates from the design load.

  6. Combined Euler column vibration isolation and energy harvesting

    NASA Astrophysics Data System (ADS)

    Davis, R. B.; McDowell, M. D.

    2017-05-01

    A new device that combines vibration isolation and energy harvesting is modeled, simulated, and tested. The vibration isolating portion of the device uses post-buckled beams as its spring elements. Piezoelectric film is applied to the beams to harvest energy from their dynamic flexure. The entire device operates passively on applied base excitation and requires no external power or control system. The structural system is modeled using the elastica, and the structural response is applied as forcing on the electric circuit equation to predict the output voltage and the corresponding harvested power. The vibration isolation and energy harvesting performance is simulated across a large parameter space and the modeling approach is validated with experimental results. Experimental transmissibilities of 2% and harvested power levels of 0.36 μW are simultaneously demonstrated. Both theoretical and experimental data suggest that there is not necessarily a trade-off between vibration isolation and harvested power. That is, within the practical operational range of the device, improved vibration isolation will be accompanied by an increase in the harvested power as the forcing frequency is increased.

  7. Performance analysis and experiment validation of a pneumatic vibration isolator

    NASA Astrophysics Data System (ADS)

    Yang, Yuanyuan; Tan, Jiubin; Wang, Lei; Zhou, Tong

    2015-02-01

    A performance analysis and experiment validation of a pneumatic vibration isolator (PVI) that applied in the wafer stage of lithography is proposed in this work. The wafer stage of lithography is a dual-stage actuator system, including a long-stroke stage (LS) and a short-stroke stage (SS). In order to achieve the nanometer level positioning the isolator is designed to reduce the transmission of LS excitations to SS. In addition, considering the SS with six degrees of freedom and required to keep a strict constant temperature environment, the isolator need to have two functions, including the decoupling for vertical to horizontal and gravity compensation. In this isolator, a biaxial hinge was designed to decouple vertical rotation freedom, and a gas bearing was designed to decouple horizontal motion. The stiffness and damping of the pneumatic vibration isolator were analyzed. Besides, an analysis of the natural frequency and vibration transmissibility of the isolator is presented. In the end, the results show that vibration transmission is reduced significantly by the isolator and natural frequency can be lower than 0.6 Hz. This means that experimental results accord with the prediction model.

  8. Vibration isolation system for cryogenic phonon-scintillation calorimeters

    NASA Astrophysics Data System (ADS)

    Lee, C.; Jo, H. S.; Kang, C. S.; Kim, G. B.; Kim, I.; Kim, S. R.; Kim, Y. H.; Lee, H. J.; So, J. H.; Yoon, Y. S.

    2017-02-01

    Cryogen-free dilution refrigerators are getting popular for rare event searches underground due to their advantages. However, the application of a pulse tube refrigerator introduces mechanical vibration that can translate into temperature fluctuation for calorimeters. The effect is significant in particular when the sensor is attached to a large absorber. A mechanical filter is installed to isolate the calorimeters from the vibration inside a cryogen-free dilution refrigerator while meeting thermal requirements.

  9. Microgravity testing a surgical isolation containment system for Space Station use

    NASA Technical Reports Server (NTRS)

    Markham, Sanford M.; Rock, John A.

    1991-01-01

    Anticipated hazards for crewmembers in future long term space flights may result in a variety of injuries including trauma and burns. Management of these injuries will require special techniques because of the lack of gravity, limitations of space and environmental restrictions. A small surgical isolation containment system was developed and tested in microgravity. The chamber provided both protection of the injury and of the cabin environment and is felt to be the most effective means of trauma and burn care in future Health Maintenance Facilities planned for prolonged space exposure.

  10. Development of active vibration isolation system for precision machines

    NASA Astrophysics Data System (ADS)

    Li, H. Z.; Lin, W. J.; Yang, G. L.

    2010-03-01

    It is a common understanding by manufacturers of precision machines that vibrations are a potentially disastrous threat to precision and throughput. To satisfy the quest for more stable processes and tighter critical dimension control in the microelectronics manufacturing industry, active vibration control becomes increasingly important for high-precision equipment developers. This paper introduced the development of an active vibration isolation system for precision machines. Innovative mechatronic approaches are investigated that can effectively suppress both environmental and payload-generated vibration. In this system, accelerometers are used as the feedback sensor, voice coil motors are used to generate the counter force, and a TI DSP controller is used to couple sensor measurements to actuator forces via specially designed control algorithms in real-time to counteract the vibration disturbances. Experimental results by using the developed AVI prototype showed promising performance on vibration attenuation. It demonstrated a reduction of the settling time from 2s to 0.1s under impulsive disturbances; and a vibration attenuation level of more than 20dB for harmonic disturbances. The technology can be used to suppress vibration for a wide range of precision machines to achieve fast settling time and higher accuracy.

  11. Development of active vibration isolation system for precision machines

    NASA Astrophysics Data System (ADS)

    Li, H. Z.; Lin, W. J.; Yang, G. L.

    2009-12-01

    It is a common understanding by manufacturers of precision machines that vibrations are a potentially disastrous threat to precision and throughput. To satisfy the quest for more stable processes and tighter critical dimension control in the microelectronics manufacturing industry, active vibration control becomes increasingly important for high-precision equipment developers. This paper introduced the development of an active vibration isolation system for precision machines. Innovative mechatronic approaches are investigated that can effectively suppress both environmental and payload-generated vibration. In this system, accelerometers are used as the feedback sensor, voice coil motors are used to generate the counter force, and a TI DSP controller is used to couple sensor measurements to actuator forces via specially designed control algorithms in real-time to counteract the vibration disturbances. Experimental results by using the developed AVI prototype showed promising performance on vibration attenuation. It demonstrated a reduction of the settling time from 2s to 0.1s under impulsive disturbances; and a vibration attenuation level of more than 20dB for harmonic disturbances. The technology can be used to suppress vibration for a wide range of precision machines to achieve fast settling time and higher accuracy.

  12. Active vibration isolation through a Stewart platform with piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Wang, Chaoxin; Xie, Xiling; Chen, Yanhao; Zhang, Zhiyi

    2016-09-01

    A Stewart platform with piezoelectric actuators is presented for micro-vibration isolation. The Jacobian matrix of the Stewart platform, which reveals the relationship between the position/pointing of the payload and the extensions of the struts, is derived by the kinematic analysis and modified according to measured FRFs(frequency response function). The dynamic model of the Stewart platform is established by the FRF synthesis method to accommodate flexible modes of the platform. In active isolation, the LMS-based adaptive method is adopted and combined with the Jacobian matrix to suppress pure vibrations of the payload. Numerical simulations and experiments were conducted to prove vibration isolation performance of the Stewart platform subjected to periodical disturbances, and the results have demonstrated that considerable attenuations can be achieved.

  13. Control of internal resonances in vibration isolators using passive and hybrid dynamic vibration absorbers

    NASA Astrophysics Data System (ADS)

    Du, Yu; Burdisso, Ricardo A.; Nikolaidis, Efstratios

    2005-09-01

    This paper discusses methods to improve isolator performance by controlling Internal Resonances (IRs), also referred as wave effects, in vibration isolators. The IRs are associated with the isolators' internal elastic motions that are due to the inertia existing in practical vibration isolators. It is well known that the IRs degrade the isolator performance as predicted by ideal massless isolator models. This degradation could be as high as 20-30 dB in the force transmissibility at the IR frequencies and 10-20 dB in the overall noise radiation from the foundation in the audible frequency range. This paper proposes two approaches of using dynamic vibration absorbers (DVAs) directly embedded into the isolator to attenuate the IRs. The first approach uses passive DVAs (PDVA). The effectiveness of this approach is investigated analytically using a 3 dof vibration model. It is shown that the PDVAs are very effective in attenuating the IRs and improve the isolator's performance at high frequencies. However, the PDVAs are less effective at low frequencies. To complement the effectiveness of the PDVA, an active control force is added, forming the hybrid DVA (HDVA) approach. The effectiveness of both the PDVA and the HDVA approaches, as well as the significance of the IRs in a commercial rubber mount, is also demonstrated experimentally. It is shown that an enhanced isolator with DVAs outperforms the original isolator without DVAs. Compared to the original isolator, in the isolation region of the experimental system, the PDVA approach reduces force transmissibility by 18.5% and overall noise radiation by 4.3 dB. The HDVA approach reduces the force transmissibility and radiated noise by 92.2% and 9.1 dB, respectively.

  14. An active vibration isolation system using adaptive proportional control method

    NASA Astrophysics Data System (ADS)

    Liu, Yun-Hui; Hsieh, Hung-En; Wu, Wei-Hao

    2014-03-01

    This paper is concerned with a six-degree-of-freedom active vibration isolation system using voice coil actuators with absolute velocity feedback control for highly sensitive measurement equipment, e.g. atomic force microscopes, suffering from building vibration. The main differences between this type of system and traditional isolator, is that there are no isolator resonance. The absolute vibration velocity signal acquired from an accelerator and being processed through an integrator is input to the controller as a feedback signal, and the controller output signal drives the voice coil actuator to produce a sky-hook damper force. In practice, the phase response of integrator at low frequency such as 2~6 Hz deviate from the 90 degree which is the exact phase difference between the vibration velocity and acceleration. Therefore, an adaptive filter is used to compensate the phase error in this paper. An analysis of this active vibration isolation system is presented, and model predictions are compared to experimental results. The results show that the proposed method significantly reduces transmissibility at resonance without the penalty of increased transmissibility at higher frequencies.

  15. A 6-DOF vibration isolation system for hydraulic hybrid vehicles

    NASA Astrophysics Data System (ADS)

    Nguyen, The; Elahinia, Mohammad; Olson, Walter W.; Fontaine, Paul

    2006-03-01

    This paper presents the results of vibration isolation analysis for the pump/motor component of hydraulic hybrid vehicles (HHVs). The HHVs are designed to combine gasoline/diesel engine and hydraulic power in order to improve the fuel efficiency and reduce the pollution. Electric hybrid technology is being applied to passenger cars with small and medium engines to improve the fuel economy. However, for heavy duty vehicles such as large SUVs, trucks, and buses, which require more power, the hydraulic hybridization is a more efficient choice. In function, the hydraulic hybrid subsystem improves the fuel efficiency of the vehicle by recovering some of the energy that is otherwise wasted in friction brakes. Since the operation of the main component of HHVs involves with rotating parts and moving fluid, noise and vibration are an issue that affects both passengers (ride comfort) as well as surrounding people (drive-by noise). This study looks into the possibility of reducing the transmitted noise and vibration from the hydraulic subsystem to the vehicle's chassis by using magnetorheological (MR) fluid mounts. To this end, the hydraulic subsystem is modeled as a six degree of freedom (6-DOF) rigid body. A 6-DOF isolation system, consisting of five mounts connected to the pump/motor at five different locations, is modeled and simulated. The mounts are designed by combining regular elastomer components with MR fluids. In the simulation, the real loading and working conditions of the hydraulic subsystem are considered and the effects of both shock and vibration are analyzed. The transmissibility of the isolation system is monitored in a wide range of frequencies. The geometry of the isolation system is considered in order to sustain the weight of the hydraulic system without affecting the design of the chassis and the effectiveness of the vibration isolating ability. The simulation results shows reduction in the transmitted vibration force for different working cycles of

  16. Dual stage passive vibration isolation for optical interferometer missions

    NASA Astrophysics Data System (ADS)

    Bronowicki, Allen J.; MacDonald, Rhonda; Gürsel, Yekta; Goullioud, Renaud; Neville, Timothy; Platus, David L.

    2003-02-01

    Future space-based optical instruments such as the Space Interferometer Mission have vibration-induced error allocations at the levels of a few nano-meters and milli-arc-seconds. A dual stage passive isolation approach has been proposed using isolation first at the vibration-inducing reaction wheels, and a second isolation layer between the bus portion of the space vehicle (the backpack) and the optical payload. The development of the backpack isolator is described, with unit transmissibility results for individual isolator struts. The dual stage isolation approach is demonstrated on a dynamically feature-rich, 7-meter structural testbed (STB3). A new passive suspension that mitigates ground vibrations above 0.4 Hz has been integrated into the testbed. A series of OPD performance predictions have been made using measured transfer functions. These indicate that the 5-nm dynamic OPD allocation is within reach using the dual isolator approach. Demonstrating these low response levels in a noisy air environment has proven to be difficult. We are sequentially executing a plan to mitigate acoustic transmission between backpack and flight structure, as well as developing techniques to mitigate effects of background acoustic noise.

  17. Performance of a Smart Vibration Isolator for Precision Spacecraft Instruments

    NASA Technical Reports Server (NTRS)

    Regelbrugge, Marc E.; Carrier, Alain; Dickson, William C.

    1996-01-01

    Under the ARPA SMS Partnership Program for Synthesis and Processing of Smart Materials, Lockheed Missiles and Space company, Inc. has developed a demonstration prototype vibration cancelling mount using electrostrictive ceramic and shape-memory alloy actuators. Shape-memory actuators provide an adaptive-passive, self-damping support for isolation, while the electrostrictive actuators are employed to provide force and position control. The demonstration device was designed to address generic requirements for vibration stabilization of precision spacecraft instruments. It is reconfigurable to operate in any of four modes; passive isolation, active-passive isolation using force cancellation, active precision positioning, and active disturbance rejection. The presentation summarizes design of the device design and results of experimental evaluations of the device in isolation (active and passive) and positioning modes. Rejection of payload-borne disturbances is also discussed with reference to predictions from experimentally calibrated simulations. Finally, avenues for further development and refinement of the device are discussed.

  18. Vibration Isolation Design for the Micro-X Rocket Payload

    NASA Technical Reports Server (NTRS)

    Heine, S. N. T.; Figueroa-Feliciano, E.; Rutherford, J. M.; Wikus, P.; Oakley, P.; Porter, Frederick S.; McCammon, D.

    2014-01-01

    Micro-X is a NASA-funded, sounding rocket-borne X-ray imaging spectrometer that will allow high precision measurements of velocity structure, ionization state and elemental composition of extended astrophysical systems. One of the biggest challenges in payload design is to maintain the temperature of the detectors during launch. There are several vibration damping stages to prevent energy transmission from the rocket skin to the detector stage, which causes heating during launch. Each stage should be more rigid than the outer stages to achieve vibrational isolation. We describe a major design effort to tune the resonance frequencies of these vibration isolation stages to reduce heating problems prior to the projected launch in the summer of 2014.

  19. Vibration Isolation Design for the Micro-X Rocket Payload

    NASA Astrophysics Data System (ADS)

    Heine, S. N. T.; Figueroa-Feliciano, E.; Rutherford, J. M.; Wikus, P.; Oakley, P.; Porter, F. S.; McCammon, D.

    2014-09-01

    Micro-X is a NASA-funded, sounding rocket-borne X-ray imaging spectrometer that will allow high precision measurements of velocity structure, ionization state and elemental composition of extended astrophysical systems. One of the biggest challenges in payload design is to maintain the temperature of the detectors during launch. There are several vibration damping stages to prevent energy transmission from the rocket skin to the detector stage, which causes heating during launch. Each stage should be more rigid than the outer stages to achieve vibrational isolation. We describe a major design effort to tune the resonance frequencies of these vibration isolation stages to reduce heating problems prior to the projected launch in the summer of 2014.

  20. Hydrofoil vibration and noise reduction with leading edge isolation

    NASA Astrophysics Data System (ADS)

    Brungart, Timothy A.; Myer, Eric C.; Capone, Dean E.; Campbell, Robert L.

    2005-09-01

    A technique for reducing the vibration and noise from hydrofoils subject to unsteady hydrodynamic loads was demonstrated experimentally. Unsteady loads are generated when hydrofoils interact with approach-flow disturbances such as hull boundary layer turbulence or wakes from upstream rotors. Since the unsteady loads are known to be concentrated in the vicinity of the leading edge, a single stage vibration isolation mount was incorporated into a hydrofoil at its 20% chord location to inhibit the leading edge-generated unsteady loads from being transmitted to the remainder of the foil and any structures coupled to it. The hydrofoil was tested in a water tunnel facility with a wake generator placed upstream to produce the approach-flow disturbances. The reduction in the loading on the portion of the hydrofoil isolated from the leading edge was inferred from vibration measurements. Reductions of 5 to 10 dB were demonstrated.

  1. Helicopter vibration isolation: Design approach and test results

    NASA Astrophysics Data System (ADS)

    Lee, C.-M.; Goverdovskiy, V. N.; Sotenko, A. V.

    2016-03-01

    This paper presents a strategy based on the approach of designing and inserting into helicopter vibration isolation systems mountable mechanisms with springs of adjustable sign-changing stiffness for system stiffness control. A procedure to extend the effective area of stiffness control is presented; a set of parameters for sensitivity analysis and practical mechanism design is formulated. The validity and flexibility of the approach are illustrated by application to crewmen seat suspensions and vibration isolators for equipment protection containers. The strategy provides minimization of vibrations, especially in the infra-low frequency range which is the most important for crewmen efficiency and safety of the equipment. This also would prevent performance degradation of some operating systems. The effectiveness is demonstrated through measured data obtained from development and parallel flight tests of new and operating systems.

  2. Nineteenth International Microgravity Measurements Group Meeting

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard (Compiler)

    2000-01-01

    The Microgravity Measurements Group meetings provide a forum for an exchange of information and ideas about various aspects of microgravity acceleration research in international microgravity research programs. These meetings are sponsored by the PI Microgravity Services (PIMS) project at the NASA Glenn Research Center. The 19th MGMG meeting was held 11-13 July 2000 at the Sheraton Airport Hotel in Cleveland, Ohio. The 44 attendees represented NASA, other space agencies, universities, and commercial companies; 8 of the attendees were international representatives from Japan, Italy, Canada, Russia, and Germany. Twenty-seven presentations were made on a variety of microgravity environment topics including the International Space Station (ISS), acceleration measurement and analysis results, science effects from microgravity accelerations, vibration isolation, free flyer satellites, ground testing, vehicle characterization, and microgravity outreach and education. The meeting participants also toured three microgravity-related facilities at the NASA Glenn Research Center. Contained within the minutes is the conference agenda, which indicates each speaker, the title of their presentation, and the actual time of their presentation. The minutes also include the charts for each presentation, which indicate the authors' name(s) and affiliation. In some cases, a separate written report was submitted and has been Included here

  3. Wakata uses Treadmill Vibration Isolation and Stabilization (TVIS)

    NASA Image and Video Library

    2009-03-22

    ISS018-E-042662 (22 March 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 18 flight engineer, equipped with a bungee harness, exercises on the Treadmill Vibration Isolation System (TVIS) in the Zvezda Service Module of the International Space Station while Space Shuttle Discovery (STS-119) remains docked with the station.

  4. Variable-Tension-Cord Suspension/Vibration-Isolation System

    NASA Technical Reports Server (NTRS)

    Villemarette, Mark L.; Boston, Joshua; RInks, Judith; Felice, Pat; Stein, Tim; Payne, Patrick

    2006-01-01

    A system for mechanical suspension and vibration isolation of a machine or instrument is based on the use of Kevlar (or equivalent aromatic polyamide) cord held in variable tension between the machine or instrument and a surrounding frame. The basic concept of such a tensioned-cord suspension system (including one in which the cords are made of aromatic polyamide fibers) is not new by itself; what is new here is the additional provision for adjusting the tension during operation to optimize vibration- isolation properties. In the original application for which this system was conceived, the objective is to suspend a reciprocating cryocooler aboard a space shuttle and to prevent both (1) transmission of launch vibrations to the cryocooler and (2) transmission of vibrations from the cryocooler to samples in a chamber cooled by the cryocooler. The basic mechanical principle of this system can also be expected to be applicable to a variety of other systems in which there are requirements for cord suspension and vibration isolation. The reciprocating cryocooler of the original application is a generally axisymmetric object, and the surrounding frame is a generally axisymmetric object with windows (see figure). Two cords are threaded into a spoke-like pattern between attachment rings on the cryocooler, holes in the cage, and cord-tension- adjusting assemblies. Initially, the cord tensions are adjusted to at least the level necessary to suspend the cryocooler against gravitation. Accelerometers for measuring vibrations are mounted (1) on the cold tip of the cryocooler and (2) adjacent to the cage, on a structure that supports the cage. During operation, a technician observes the accelerometer outputs on an oscilloscope while manually adjusting the cord tensions in an effort to minimize the amount of vibration transmitted to and/or from the cryocooler. A contemplated future version of the system would include a microprocessor-based control subsystem that would include cord

  5. Vibration isolation system for the Stratospheric Observatory For Infrared Astronomy (SOFIA)

    NASA Technical Reports Server (NTRS)

    Kaiser, T.; Kunz, N.

    1988-01-01

    The Vibration Isolation System for the Stratospheric Observatory for Infrared Astronomy (SOFIA) is studied. Included are discussions of the various concepts, design goals, concerns, and the proposed configuration for the Vibration Isolation System.

  6. Seismic shock and vibration isolation 1995. Part 2: Applications

    SciTech Connect

    Mok, G.C.; Chung, H.H.

    1995-07-11

    As pointed out in the introduction of Part 1, the isolation strategy can be used to effectively decouple a` structure from its environment and thus the structure can be protected from damaging seismic loads or unwanted vibrations and noises from the environment. The method has been used for solving vibration and shock problems in machinery and equipment for many years, but its application to the protection of structures from seismic loadings is relatively recent. Owing to the current interest generated by the Northridge and Kobe earthquakes, an but one of the papers in this publication deal with seismic isolation. The one paper on vibration isolation by Yonekura discusses a measure to protect buildings from detrimental excitations of running trains. Seismic or base isolation has been used to protect bridges, buildings, industrial facilities, and nuclear reactors from damaging seismic loads since 1970. For each of these applications base isolation offers some unique advantages that the conventional strengthening method cannot. Some of these advantages are discussed in papers presented in this publication.

  7. Design of a vibration isolation system for a cycle ergometer to be used onboard the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Pearson, Lillian; Tait, Steven; Trevino, Maurice

    1991-01-01

    Low frequency vibrations generated during exercise using the cycle ergometer onboard the Space Shuttle are disrupting sensitive microgravity experiments. The design team is asked by NASA/USRA to generate alternatives for the design of a vibration isolation system for the cycle ergometer. It is the design team's objective to present alternative designs and a problem solution for a vibration isolation system for an exercise cycle ergometer to be used onboard the Space Shuttle. In the development of alternative designs, the design team emphasizes passive systems as opposed to active control systems. This decision is made because the team feels that passive systems are less complex than active control systems, external energy sources are not required, and mass is reduced due to the lack of machinery such as servomotors or compressors typical of active control systems. Eleven alternative designs are developed by the design team. From these alternatives, three active control systems are included to compare the benefits of active and passive systems. Also included in the alternatives is an isolation system designed by an independent engineer that was acquired late in the project. The eight alternatives using passive isolation systems are narrowed down by selection criteria to four considered to be the most promising by the design team. A feasibility analysis is performed on these four passive isolation systems. Based on the feasibility analysis, a final design solution is chosen and further developed. From the development of the design, the design team has concluded that passive systems are not effective at isolating vibrations for the low frequencies considered for this project. Recommendations are made for guidelines of passive isolation design and application of such systems.

  8. A Sub-Hertz, Low-Frequency Vibration Isolation Platform

    NASA Technical Reports Server (NTRS)

    Ortiz, Gerardo, G.; Farr, William H.; Sannibale, Virginio

    2011-01-01

    One of the major technical problems deep-space optical communication (DSOC) systems need to solve is the isolation of the optical terminal from vibrations produced by the spacecraft navigational control system and by the moving parts of onboard instruments. Even under these vibration perturbations, the DSOC transceivers (telescopes) need to be pointed l000 fs of times more accurately than an RF communication system (parabolic antennas). Mechanical resonators have been extensively used to provide vibration isolation for groundbased, airborne, and spaceborne payloads. The effectiveness of these isolation systems is determined mainly by the ability of designing a mechanical oscillator with the lowest possible resonant frequency. The Low-Frequency Vibration Isolation Platform (LFVIP), developed during this effort, aims to reduce the resonant frequency of the mechanical oscillators into the sub-Hertz region in order to maximize the passive isolation afforded by the 40 dB/decade roll-off response of the resonator. The LFVIP also provides tip/tilt functionality for acquisition and tracking of a beacon signal. An active control system is used for platform positioning and for dampening of the mechanical oscillator. The basic idea in the design of the isolation platform is to use a passive isolation strut with an approximately equal to 100-mHz resonance frequency. This will extend the isolation range to lower frequencies. The harmonic oscillator is a second-order lowpass filter for mechanical disturbances. The resonance quality depends on the dissipation mechanisms, which are mainly hysteretic because of the low resonant frequency and the absence of any viscous medium. The LFVIP system is configured using the well-established Stewart Platform, which consists of a top platform connected to a base with six extensible struts (see figure). The struts are attached to the base and to the platform via universal joints, which permit the extension and contraction of the struts. The

  9. Vibration Isolation Design for the Micro-X Rocket Payload

    NASA Astrophysics Data System (ADS)

    Danowski, M. E.; Heine, S. N. T.; Figueroa-Feliciano, E.; Goldfinger, D.; Wikus, P.; McCammon, D.; Oakley, P.

    2016-08-01

    Micro-X is a NASA-funded sounding rocket-borne X-ray imaging spectrometer designed to enable high precision measurements of extended astrophysical systems. To perform high energy resolution measurements and capture unprecedented spectra of supernova remnants and galaxy clusters, Micro-X must maintain tight temperature control. One of the biggest challenges in payload design is to prevent heating of the detectors due to the vibrational loads on the rocket skin during launch. Several stages of vibration damping systems are implemented to prevent energy transmission from the rocket skin to the detector stage, each stage more rigid than the last. We describe recent redesign efforts to improve this vibration isolation by tuning the resonant frequencies of the various stages to minimize heating prior to the projected launch in 2016.

  10. Evaluation of actuators for the SDOF and MDOF active microgravity isolation systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The University of Virginia examined the design of actuators for both single-degree-of-freedom (SDOF) and multiple-degree-of-freedom (MDOF) active microgravity isolation systems. For SDOF systems, two actuators were considered: a special large gap magnetic actuator and a large stroke Lorentz actuator. The magnetic actuator was viewed to be of greater difficulty than the Lorentz actuator with little compelling technical advantage and was dropped from consideration. A Lorentz actuator was designed and built for the SDOF test rig using magnetic circuit and finite element analysis. The design and some experimental results are discussed. The University also examined the design of actuators for MDOF isolation systems. This includes design of an integrated 1 cm gap 6-DOF noncontacting magnetic suspension system and of a 'coarse' follower which permits the practical extension of magnetic suspension to large strokes. The proposed 'coarse' actuator was a closed kinematic chain manipulator known as a Stewart Platform. The integration of the two isolation systems together, the isolation tasks assigned to each, and possible control architectures were also explored. The results of this research are examined.

  11. Evaluation of passive and active vibration control mechanisms in a microgravity environment

    NASA Technical Reports Server (NTRS)

    Ellison, J.; Ahmadi, G.; Grodsinsky, C.

    1993-01-01

    The behavior of equipment and their light secondary attachments in large space structures under orbital excitation is studied. The equipment is modeled as a shear beam and its secondary attachment is treated as a single-degree-of-freedom lumped mass system. Peak responses of the equipment and its secondary system for a variety of vibration control mechanisms are evaluated. A novel active friction control mechanism, by varying the normal force, is suggested. The device uses a magnetic field control to minimize the stick condition, thereby reducing the overall structural response. The results show that the use of the passive vibration control devices could reduce the peak equipment responses to a certain extent. However, major reduction of vibration levels could be achieved only by the use of active devices. Using active control of the interface normal force, the peak responses of the equipment and its attachment are reduced by a factor of 10 over the fixed-base equipment response.

  12. Launch vehicle payload adapter design with vibration isolation features

    NASA Astrophysics Data System (ADS)

    Thomas, Gareth R.; Fadick, Cynthia M.; Fram, Bryan J.

    2005-05-01

    Payloads, such as satellites or spacecraft, which are mounted on launch vehicles, are subject to severe vibrations during flight. These vibrations are induced by multiple sources that occur between liftoff and the instant of final separation from the launch vehicle. A direct result of the severe vibrations is that fatigue damage and failure can be incurred by sensitive payload components. For this reason a payload adapter has been designed with special emphasis on its vibration isolation characteristics. The design consists of an annular plate that has top and bottom face sheets separated by radial ribs and close-out rings. These components are manufactured from graphite epoxy composites to ensure a high stiffness to weight ratio. The design is tuned to keep the frequency of the axial mode of vibration of the payload on the flexibility of the adapter to a low value. This is the main strategy adopted for isolating the payload from damaging vibrations in the intermediate to higher frequency range (45Hz-200Hz). A design challenge for this type of adapter is to keep the pitch frequency of the payload above a critical value in order to avoid dynamic interactions with the launch vehicle control system. This high frequency requirement conflicts with the low axial mode frequency requirement and this problem is overcome by innovative tuning of the directional stiffnesses of the composite parts. A second design strategy that is utilized to achieve good isolation characteristics is the use of constrained layer damping. This feature is particularly effective at keeping the responses to a minimum for one of the most important dynamic loading mechanisms. This mechanism consists of the almost-tonal vibratory load associated with the resonant burn condition present in any stage powered by a solid rocket motor. The frequency of such a load typically falls in the 45-75Hz range and this phenomenon drives the low frequency design of the adapter. Detailed finite element analysis is

  13. Passive Micro Vibration Isolator Utilizing Flux Pinning Effect for Satellites

    NASA Astrophysics Data System (ADS)

    Shibata, Takuma; Sakai, Shin-ichiro

    2016-09-01

    Information related to the origin of space and evolution of galaxy can be obtained using the observation satellites. In recent years, high pointing accuracy is demanded for getting more detailed data about distant stars and galaxies. As a result, vibration isolators that consist of a main structure and a TTM (Tip Tilt Mirror) have been adopted for observation satellites. However, cutting the low frequency vibrations off passively with the conventional methods is difficult. A vibration isolator that uses pinning effect is proposed for solving this problem. The pinning effect is acquired by cooling the type-II superconductor below the critical temperature and it generates a pinning force to maintain the relative distance and attitude between a type- II superconductor and a material that generates magnetic flux. The mission part and the bus part of the satellite are equipped with superconductors and permanent magnets and these parts perform short distance formation flight by applying the effect. This method can cut vibrations from low to high frequency bands off passively. In addition, Meissner effect can prevent collision of the mission and bus parts. In order to investigate the performance of this system, experiments and simulations are carried out and the results are discussed.

  14. Vibration isolation and damping in high precision equipment

    NASA Astrophysics Data System (ADS)

    Bukkems, B.; Ruijl, T.; Simons, J.

    2017-06-01

    All systems located in a laboratory environment or factory are subject to disturbances. These disturbances can either come from the surroundings, e.g. floor-induced vibrations, or from the system itself, e.g. stage-induced vibrations. In many cases it is needed to minimize the effect of these disturbances. This can either be done by isolating the system from its disturbance source or by applying damping to the system. In this paper we present various cases in which we have effectively reduced the impact of disturbances on the system's performance, either by improving its isolation system, by minimizing the impact of stage reaction forces, or by designing polymer damping into the system.

  15. Performance evaluation of spaceborne cryocooler micro-vibration isolation system employing pseudoelastic SMA mesh washer

    NASA Astrophysics Data System (ADS)

    Kwon, Seong-Cheol; Jeon, Su-Hyeon; Oh, Hyun-Ung

    2015-04-01

    A spaceborne cryocooler produces undesirable micro-vibration disturbances during its on-orbit operation, which is one of the main sources of degradation of the image quality of high-resolution observation satellites. Therefore, to comply with the strict mission requirement for the acquisition of high-quality images, micro-vibration disturbances induced by cryocooler operation need to be isolated. In this study, we proposed a spaceborne cryocooler micro-vibration isolator that employs a pseudoelastic shape memory alloy (SMA) mesh washer, which guarantees vibration isolation performance in a severe launch vibration environment while effectively isolating the micro-vibrations from the cryocooler on-orbit. Basic characteristics of the cryocooler assembly integrated with the proposed isolators were measured through static tests and free vibration tests. The effectiveness of the isolator design was demonstrated by the micro-vibration measurement tests under qualification temperature limits.

  16. Application of adaptive trusses to vibration isolation in flexible structures

    NASA Technical Reports Server (NTRS)

    Clark, William W.; Robertshaw, Harry H.

    1992-01-01

    It is shown through analysis that force feedback can be used to provide complete vibration isolation in two directions. Simultations were carried out to demonstrate the use of two control methods applied to an adaptive truss as an active mount. The first technique was simple force feedback with a gain. This method has the potential to provide excellent vibration isolation performance. It requires no model of the system and no knowledge of the applied disturbance, and is easily implemented in an adaptive truss. There is some question as to how high the gain can be allowed to go but the experimental results have shown performance advantages over passive techniques even for small gains. The second technique presented is the LQR method, with disturbance modeling. A method is presented for using the LQR method for vibration isolation with the intention of achieving performance with guaranteed stability and relatively lower loop gains. The overhead for those benefits is an accurate system model. It was shown analytically that this method works; however, the performance is not as good as expected. It is believed that the difference in performance is partly due to an increase in active damping which is inadvertently provided by the LQR method.

  17. Damping phenomena in a wire rope vibration isolation system

    NASA Technical Reports Server (NTRS)

    Tinker, Michael L.; Cutchins, Malcolm A.

    1990-01-01

    A study of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators is presented. Emphasis is placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase trajectories, and frequency response curves were obtained. A semi-empirical model having nonlinear stiffness, nth-power velocity damping, and variable Coulomb friction damping is developed and results are compared to experimental data. Conclusions about dynamic phenomena in the wire rope system are made based on the experimental and semi-empirical results.

  18. Use of a Slick-Plate as a Contingency Exercise Surface for the Treadmill With Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Loehr, James A.; Lee, Stuart M. C.; Schneider, Suzanne M.

    2003-01-01

    The treadmill with vibration isolation system (TVIS) was developed to counteract cardiovascular, musculoskeletal, and neurovestibular deconditioning during long-duration missions to the International Space Station (ISS). However, recent hardware failures have necessitated the development of a short-term, temporary contingency exercise countermeasure for TVIS until nominal operations could be restored. The purpose of our evaluation was twofold: 1) to examine whether a slick-plate/contingency exercise surface (CES) could be used as a walking/running surface and could elicit a heart rate (HR) greater than or equal to 70% HR maximum and 2) to determine the optimal hardware configuration, in microgravity, to simulate running/walking in a 1-g environment. One subject (male) participated in the slick surface evaluation and two subjects (one male, one female) participated in the microgravity evaluation of the slick surface configuration. During the slick surface evaluation, the subject was suspended in a parachute harness and bungee cord configuration to offset the subject#s body weight. Using another bungee cord configuration, we added a vertical load back to the subject, who was then asked to run for 20 minutes on the slick surface. The microgravity evaluation simulated the ISS TVIS, and we evaluated two different slick surfaces (Teflon surface and an aluminum surface coated with Tufram) for use as a CES. We evaluated each surface with the subject walking and running, with and without a handrail, and while wearing either socks or nylon booties over shoes. In the slick surface evaluation, the subject ran for 20 minutes and reached a maximum HR of 170 bpm. In the microgravity evaluation, the subjects chose the aluminum plate coated with Tufram as the CES, while wearing a pair of nylon booties over running shoes and using a handrail, as the optimal hardware configuration.

  19. a Hybrid-Type Active Vibration Isolation System Using Neural Networks

    NASA Astrophysics Data System (ADS)

    Ahn, K. G.; Pahk, H. J.; Jung, M. Y.; Cho, D. W.

    1996-05-01

    Vibration isolation of mechanical systems is achieved through either passive or active vibration control systems. Although a passive vibration isolation system offers simple and reliable means to protect mechanical systems from a vibration environment, it has inherent performance limitations, that is, its controllable frequency range is limited and the shape of its transmissibility does not change. Recently, in some applications, such as active suspensions or precise vibration systems, active vibration isolation systems have been employed to overcome the limitations of the passive systems. In this paper, a hybrid-type active vibration isolation system that uses electromagnetic and pneumatic force is developed, and a new control algorithm adopting neural networks is proposed. The characteristics of the hybrid system proposed in the paper were investigated via computer simulation and experiments. It was shown that the transmissibility of the vibration isolation system could be kept below 0.63 over the entire frequency range, including the resonance frequency.

  20. Characteristics of spaceborne cooler passive vibration isolator by using a compressed shape memory alloy mesh washer

    NASA Astrophysics Data System (ADS)

    Oh, Hyun-Ung; Kwon, Seong-Cheol; Youn, Se-Hyun

    2015-01-01

    Cryogenic coolers produce undesirable micro-vibrations during on-orbit operation, which may seriously affect the image quality of high-resolution observation satellites. Micro-vibrations can be easily isolated by mounting the cooler on a vibration isolator with low stiffness to attenuate the vibration transmitted to the satellite structure. However, the structural safety of a cooler supported by an isolator with low stiffness cannot be guaranteed under the much more severe vibration condition of a launch environment. In this study, to guarantee vibration isolation performance in a launch environment while effectively isolating the micro-vibrations from the cooler on-orbit, a new type of passive vibration isolation system by using a compressed shape memory alloy mesh washer was proposed and investigated. The basic characteristics of the isolator were measured in static and free vibration tests of the isolator, and a simple equivalent model of the isolator was proposed. The effectiveness of the isolator design in a launch environment was demonstrated through sine vibration, random vibration, and shock tests.

  1. Magnetic Actuators and Suspension for Space Vibration Control

    NASA Technical Reports Server (NTRS)

    Knospe, Carl R.; Allaire, Paul E.; Lewis, David W.

    1993-01-01

    The research on microgravity vibration isolation performed at the University of Virginia is summarized. This research on microgravity vibration isolation was focused in three areas: (1) the development of new actuators for use in microgravity isolation; (2) the design of controllers for multiple-degree-of-freedom active isolation; and (3) the construction of a single-degree-of-freedom test rig with umbilicals. Described are the design and testing of a large stroke linear actuator; the conceptual design and analysis of a redundant coarse-fine six-degree-of-freedom actuator; an investigation of the control issues of active microgravity isolation; a methodology for the design of multiple-degree-of-freedom isolation control systems using modern control theory; and the design and testing of a single-degree-of-freedom test rig with umbilicals.

  2. Vibration isolation by exploring bio-inspired structural nonlinearity.

    PubMed

    Wu, Zhijing; Jing, Xingjian; Bian, Jing; Li, Fengming; Allen, Robert

    2015-10-08

    Inspired by the limb structures of animals/insects in motion vibration control, a bio-inspired limb-like structure (LLS) is systematically studied for understanding and exploring its advantageous nonlinear function in passive vibration isolation. The bio-inspired system consists of asymmetric articulations (of different rod lengths) with inside vertical and horizontal springs (as animal muscle) of different linear stiffness. Mathematical modeling and analysis of the proposed LLS reveal that, (a) the system has very beneficial nonlinear stiffness which can provide flexible quasi-zero, zero and/or negative stiffness, and these nonlinear stiffness properties are adjustable or designable with structure parameters; (b) the asymmetric rod-length ratio and spring-stiffness ratio present very beneficial factors for tuning system equivalent stiffness; (c) the system loading capacity is also adjustable with the structure parameters which presents another flexible benefit in application. Experiments and comparisons with existing quasi-zero-stiffness isolators validate the advantageous features above, and some discussions are also given about how to select structural parameters for practical applications. The results would provide an innovative bio-inspired solution to passive vibration control in various engineering practice.

  3. Magnetically damped vibration isolation system for a space shuttle payload

    NASA Astrophysics Data System (ADS)

    Kienholz, David A.; Smith, Christian A.; Haile, William B.

    1996-05-01

    A new vibration isolation system for a Space Shuttle payload is described. Designed for a large optical instrument to be launched aboard the next Hubble Telescope servicing mission, the system uses a set of eight telescoping struts to mount the payload to a shuttle pallet. Each strut is a combination of a titanium coil spring and a passive damper. The latter dissipates energy through eddy currents induced in a conductor moving in a dc magnetic field. The result is a simple, robust, all-metal isolation mount that is linear over a long stroke, relatively insensitive to temperature, and contains no fluids. Design of the system is described and strut- level test results are given along with predictions for system-level isolation under flight loads.

  4. Static and dynamic stability of pneumatic vibration isolators and systems of isolators

    NASA Astrophysics Data System (ADS)

    Ryaboy, Vyacheslav M.

    2014-01-01

    Pneumatic vibration isolation is the most widespread effective method for creating vibration-free environments that are vital for precise experiments and manufacturing operations in optoelectronics, life sciences, microelectronics, nanotechnology and other areas. The modeling and design principles of a dual-chamber pneumatic vibration isolator, basically established a few decades ago, continue to attract attention of researchers. On the other hand, behavior of systems of such isolators was never explained in the literature in sufficient detail. This paper covers a range of questions essential for understanding the mechanics of pneumatic isolation systems from both design and application perspectives. The theory and a model of a single standalone isolator are presented in concise form necessary for subsequent analysis. Then the dynamics of a system of isolators supporting a payload is considered with main attention directed to two aspects of their behavior: first, the static stability of payloads with high positions of the center of gravity; second, dynamic stability of the feedback system formed by mechanical leveling valves. The direct method of calculating the maximum stable position of the center of gravity is presented and illustrated by three-dimensional stability domains; analytic formulas are given that delineate these domains. A numerical method for feedback stability analysis of self-leveling valve systems is given, and the results are compared with the analytical estimates for a single isolator. The relation between the static and dynamic phenomena is discussed.

  5. Active low-frequency vertical vibration isolation system for precision measurements

    NASA Astrophysics Data System (ADS)

    Wu, Kang; Li, Gang; Hu, Hua; Wang, Lijun

    2017-01-01

    Low-frequency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling.

  6. Sensor fusion methods for high performance active vibration isolation systems

    NASA Astrophysics Data System (ADS)

    Collette, C.; Matichard, F.

    2015-04-01

    Sensor noise often limits the performance of active vibration isolation systems. Inertial sensors used in such systems can be selected through a wide variety of instrument noise and size characteristics. However, the most sensitive instruments are often the biggest and the heaviest. Consequently, high-performance active isolators sometimes embed many tens of kilograms in instrumentation. The weight and size of instrumentation can add unwanted constraint on the design. It tends to lower the structures natural frequencies and reduces the collocation between sensors and actuators. Both effects tend to reduce feedback control performance and stability. This paper discusses sensor fusion techniques that can be used in order to increase the control bandwidth (and/or the stability). For this, the low noise inertial instrument signal dominates the fusion at low frequency to provide vibration isolation. Other types of sensors (relative motion, smaller but noisier inertial, or force sensors) are used at higher frequencies to increase stability. Several sensor fusion configurations are studied. The paper shows the improvement that can be expected for several case studies including a rigid equipment, a flexible equipment, and a flexible equipment mounted on a flexible support structure.

  7. Robust control of novel pendulum-type vibration isolation system

    NASA Astrophysics Data System (ADS)

    Tsai, Meng-Shiun; Sun, Yann-Shuoh; Liu, Chun-Hsieh

    2011-08-01

    A novel pendulum-type vibration isolation system is proposed consisting of three active cables with embedded piezoelectric actuators and a passive elastomer layer. The dynamic response of the isolation module in the vertical and horizontal directions is modeled using the Lagrangian approach. The validity of the dynamic model is confirmed by comparing the simulation results for the frequency response in the vertical and horizontal directions with the experimental results. An approximate model is proposed to take into account system uncertainties such as payload changes and hysteresis effects. A robust quantitative feedback theory (QFT)-based active controller is then designed to ensure that the active control can achieve a high level of disturbance rejection in the low-frequency range even under variable loading conditions. It is shown that the controller achieves average disturbance rejection of -14 dB in the 2-60 Hz bandwidth range and -35 dB at the resonance frequency. The experimental results confirm that the proposed system achieves a robust vibration isolation performance under the payload in the range of 40-60 kg.

  8. Reaction Wheel Vibration Isolator with Elastomeric Stoppers for Launch Load

    NASA Astrophysics Data System (ADS)

    Carte, Gilles

    2014-06-01

    High resolution earth observation satellites need high pointing stability. This results in the need of isolating the on board vibration sources such as the reaction wheels. To increase the efficiency of a passive isolator, it is common to reduce the natural frequency of the suspension. But a low frequency isolator ( 10 Hz) cannot withstand the qualification nor the launch loads. It is then compulsory to assist the isolator with a complementary device such as a rigid launch lock. An alternative solution to the rigid launch lock is to introduce elastomeric stoppers to limit the dynamic displacements of the suspended reaction wheel and potentially reduce the dynamic loads applied to it. A Reaction Wheel Isolator with elastomeric stoppers has been developed in the course of the MTG program. The basic principles of this isolator will be presented as well as the ones of the elastomeric stoppers. The nonlinear behaviour of the stoppers that work with potentially intermittent contact will be explained. Some tests results will be presented to clearly demonstrate the advantages of this device.

  9. Microgravity Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    Foster, William

    2009-01-01

    Microgravity Acceleration Measurement System (MAMS) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

  10. Enhanced shock and vibration isolator for the attenuation of low-frequency vibration and high-frequency pyroshock loads

    NASA Astrophysics Data System (ADS)

    Han, Jae-Hung; Youn, Se-Hyun; Jeong, Ho-Kyung; Jang, Young-Soon

    2012-04-01

    Launch vehicles, satellites and aircrafts often experience harsh vibration and pyroshock loads during the flight including maneuvering and separation events, which may cause the malfunction of equipped electronic devices. Furthermore, this minor malfunction can generate catastrophic failure of the whole mission. To prevent malfunction of the electronic devices from severe shock and vibration loads, elastomeric isolators are commonly applied between the electronic device and the equipment bay structure in the aerospace fields. However, this rubber type elastomeric material is vulnerable to the low-frequency vibration load which involves large amount of displacement due to its low stiffness. Recently, the present authors proposed new type of isolator, called as pseudoelastic hybrid mesh isolator. This talk introduces the key features of this new pseudoelastic hybrid mesh isolator which shows better isolation performance throughout all frequency range than conventional isolators.

  11. Enhanced shock and vibration isolator for the attenuation of low-frequency vibration and high-frequency pyroshock loads

    NASA Astrophysics Data System (ADS)

    Han, Jae-Hung; Youn, Se-Hyun; Jeong, Ho-Kyung; Jang, Young-Soon

    2011-11-01

    Launch vehicles, satellites and aircrafts often experience harsh vibration and pyroshock loads during the flight including maneuvering and separation events, which may cause the malfunction of equipped electronic devices. Furthermore, this minor malfunction can generate catastrophic failure of the whole mission. To prevent malfunction of the electronic devices from severe shock and vibration loads, elastomeric isolators are commonly applied between the electronic device and the equipment bay structure in the aerospace fields. However, this rubber type elastomeric material is vulnerable to the low-frequency vibration load which involves large amount of displacement due to its low stiffness. Recently, the present authors proposed new type of isolator, called as pseudoelastic hybrid mesh isolator. This talk introduces the key features of this new pseudoelastic hybrid mesh isolator which shows better isolation performance throughout all frequency range than conventional isolators.

  12. Design of vibration isolation systems using multiobjective optimization techniques

    NASA Technical Reports Server (NTRS)

    Rao, S. S.

    1984-01-01

    The design of vibration isolation systems is considered using multicriteria optimization techniques. The integrated values of the square of the force transmitted to the main mass and the square of the relative displacement between the main mass and the base are taken as the performance indices. The design of a three degrees-of-freedom isolation system with an exponentially decaying type of base disturbance is considered for illustration. Numerical results are obtained using the global criterion, utility function, bounded objective, lexicographic, goal programming, goal attainment and game theory methods. It is found that the game theory approach is superior in finding a better optimum solution with proper balance of the various objective functions.

  13. Umbilical Stiffness Matrix Characterization and Testing for Microgravity Science Payloads

    NASA Technical Reports Server (NTRS)

    Engberg, Robert C.

    2003-01-01

    This paper describes efforts of testing and analysis of various candidate cables and umbilicals for International Space Station microgravity science payloads. The effects of looping, large vs. small displacements, and umbilical mounting configurations were assessed. A 3-DOF stepper motor driven fixture was used to excite the umbilicals. Forces and moments were directly measured in all three axes with a 6-DOF load cell in order to derive suitable stiffness matrices for design and analysis of vibration isolation controllers. Data obtained from these tests were used to help determine the optimum type and configuration of umbilical cables for the International Space Station microgravity science glovebox (MSG) vibration isolation platform. The data and procedures can also be implemented into control algorithm simulations to assist in validation of actively controlled vibration isolation systems. The experimental results of this work are specific in support of the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) isolation platform, to be located in the microgravity science glovebox aboard the U.S. Destiny Laboratory Module.

  14. Discrete optimization of isolator locations for vibration isolation systems: An analytical and experimental investigation

    SciTech Connect

    Ponslet, E.R.; Eldred, M.S.

    1996-05-17

    An analytical and experimental study is conducted to investigate the effect of isolator locations on the effectiveness of vibration isolation systems. The study uses isolators with fixed properties and evaluates potential improvements to the isolation system that can be achieved by optimizing isolator locations. Because the available locations for the isolators are discrete in this application, a Genetic Algorithm (GA) is used as the optimization method. The system is modeled in MATLAB{trademark} and coupled with the GA available in the DAKOTA optimization toolkit under development at Sandia National Laboratories. Design constraints dictated by hardware and experimental limitations are implemented through penalty function techniques. A series of GA runs reveal difficulties in the search on this heavily constrained, multimodal, discrete problem. However, the GA runs provide a variety of optimized designs with predicted performance from 30 to 70 times better than a baseline configuration. An alternate approach is also tested on this problem: it uses continuous optimization, followed by rounding of the solution to neighboring discrete configurations. Results show that this approach leads to either infeasible or poor designs. Finally, a number of optimized designs obtained from the GA searches are tested in the laboratory and compared to the baseline design. These experimental results show a 7 to 46 times improvement in vibration isolation from the baseline configuration.

  15. Vibration isolation using six degree-of-freedom quasi-zero stiffness magnetic levitation

    NASA Astrophysics Data System (ADS)

    Zhu, Tao; Cazzolato, Benjamin; Robertson, William S. P.; Zander, Anthony

    2015-12-01

    In laboratories and high-tech manufacturing applications, passive vibration isolators are often used to isolate vibration sensitive equipment from ground-borne vibrations. However, in traditional passive isolation devices, where the payload weight is supported by elastic structures with finite stiffness, a design trade-off between the load capacity and the vibration isolation performance is unavoidable. Low stiffness springs are often required to achieve vibration isolation, whilst high stiffness is desired for supporting payload weight. In this paper, a novel design of a six degree of freedom (six-dof) vibration isolator is presented, as well as the control algorithms necessary for stabilising the passively unstable maglev system. The system applies magnetic levitation as the payload support mechanism, which realises inherent quasi-zero stiffness levitation in the vertical direction, and zero stiffness in the other five dofs. While providing near zero stiffness in multiple dofs, the design is also able to generate static magnetic forces to support the payload weight. This negates the trade-off between load capacity and vibration isolation that often exists in traditional isolator designs. The paper firstly presents the novel design concept of the isolator and associated theories, followed by the mechanical and control system designs. Experimental results are then presented to demonstrate the vibration isolation performance of the proposed system in all six directions.

  16. A method of isolating treadmill shock and vibration on spacecraft

    NASA Technical Reports Server (NTRS)

    Thornton, William E.

    1989-01-01

    A major problem is currently felt to exist in the implementation of materials processing on a spacecraft. Crystal growers place requirements of one micro-g or less on the vehicle. Simple math produces startling figures for such a restriction e.g., for each ton of vehicle mass with 10(-6) g acceleration limit; Perturbing Force limit, F = .002 lb. For each 10(5) lbs F = 0.1 lb. For each 10(6) lbs F = 1.0 lb. Forces generated by normal human movement on spacecraft of 5x10(5) pounds weight are on an order-of-magnitude greater than allowed by this specification and forces generated by locomotion on a treadmill are more than two orders-of-magnitude greater. Other exercises and normal onboard functions generate forces in between. To accommodate many essential functions it is obvious that even on a vehicle as large as Space Station, a reduction of more than two orders of magnitude in force is required. Commonly used passive shock and vibration isolation devices are complex, heavy, and also would have difficulty meeting the requirements. However, by a new arrangement, adequate isolation can be obtained. Isolation of the treadmill will be treated since it is considered the most significant disturbance at this time.

  17. Note: A three-dimension active vibration isolator for precision atom gravimeters

    SciTech Connect

    Zhou, Min-Kang; Xiong, Xin; Chen, Le-Le; Cui, Jia-Feng; Duan, Xiao-Chun; Hu, Zhong-Kun

    2015-04-15

    An ultra-low frequency active vibration isolator, simultaneously suppressing three-dimensional vibration noise, is demonstrated experimentally. The equivalent natural period of the isolator is 100 s and 12 s for the vertical and horizontal direction, respectively. The vibration noise in the vertical direction is about 50 times reduced during 0.2 and 2 Hz, and 5 times reduced in the other two orthogonal directions in the same frequency range. This isolator is designed for atom gravimeters, especially suitable for the gravimeter whose sensitivity is limited by vibration couplings.

  18. Vibration/Acoustic Isolation Techniques for spectroscopic mapping STS

    NASA Astrophysics Data System (ADS)

    Alldredge, Jacob; Hoskinson, Emile; Hoffmann, Joan; Harrd, Thomas; Packard, Richard; Davis, J. C.

    2004-03-01

    Previous studies of spectroscopic mapping STS systems indicate that the coupling of mechanical, acoustic, and electrical building noise to experiments can be the limiting noise factor when making measurements. With this in mind we have set out to construct new labs that reduce or eliminate noise from the building. Here we describe the design considerations and techniques used in the construction of new, extremely low vibration lab space, to be used initially for scanning tunneling spectroscopy experiments. The lab space is decoupled from the building by placing it upon 25 ton inertial blocks (30 tons including sound room and equipment) resting on air springs. The experimental apparatus itself rests on another set of air springs. The entire space is surrounded by two nested acoustic rooms. We report on the degree of isolation achieved by these techniques.

  19. Miniature vibration isolation system for space applications: Phase II

    NASA Astrophysics Data System (ADS)

    Jacobs, Jack H.; Ross, James A.; Hadden, Steve; Gonzalez, Mario; Rogers, Zach; Henderson, B. Kyle

    2004-07-01

    In recent years, there has been a significant interest in, and move towards using highly sensitive, precision payloads on space vehicles. In order to perform tasks such as communicating at extremely high data rates between satellites using laser cross-links, or searching for new planets in distant solar systems using sparse aperture optical elements, a satellite bus and its payload must remain relatively motionless. The ability to hold a precision payload steady is complicated by disturbances from reaction wheels, control moment gyroscopes, solar array drives, stepper motors, and other devices. Because every satellite is essentially unique in its construction, isolating or damping unwanted vibrations usually requires a robust system over a wide bandwidth. The disadvantage of these systems is that they typically are not retrofittable and not tunable to changes in payload size or inertias. During the Phase I MVIS program, funded by AFRL and DARPA, a hybrid piezoelectric/D-strut isolator was built and tested to prove its viability for retroffitable insertion into sensitive payload attachments. A second phase of the program, which is jointly funded between AFRL and Honeywell, was started in November of 2002 to build a hexapod and the supporting interface electronics and do a flight demonstration of the technology. The MVIS-II program is a systems-level demonstration of the application of advanced smart materials and structures technology that will enable programmable and retrofittable vibration control of spacecraft precision payloads. This paper describes the simulations, overall test plan and product development status of the overall MVIS-II program as it approaches flight.

  20. A Vibration Isolation System for Use in a Large Thermal Vacuum Test Facility

    NASA Technical Reports Server (NTRS)

    Hershfeld, Donald; VanCampen, Julie

    2002-01-01

    A thermal vacuum payload platform that is isolated from background vibration is required to support the development of future instruments for Hubble Space Telescope (HST) and the Next Generation Space Telescope (NGST) at the Goddard Space Flight Center (GSFC). Because of the size and weight of the thermal/vacuum facility in which the instruments are tested, it is not practical to isolate the entire facility externally. Therefore, a vibration isolation system has been designed and fabricated to be installed inside the chamber. The isolation system provides a payload interface of 3.05 m (10 feet) in diameter and is capable of supporting a maximum payload weight of 4536 kg (10,000 Lbs). A counterweight system has been included to insure stability of payloads having high centers of gravity. The vibration isolation system poses a potential problem in that leakage into the chamber could compromise the ability to maintain vacuum. Strict specifications were imposed on the isolation system design to minimize leakage. Vibration measurements, obtained inside the chamber, prior to installing the vibration isolation system, indicated levels in all axes of approximately 1 milli-g at about 20 Hz. The vibration isolation system was designed to provide a minimum attenuation of 40 dB to these levels. This paper describes the design and testing of this unique vibration isolation system. Problems with leakage and corrective methods are presented. Isolation performance results are also presented.

  1. Active vibration isolation of a flexible structure mounted on a vibrating elastic base

    NASA Astrophysics Data System (ADS)

    El-Sinawi, A. H.

    2004-03-01

    The problem of isolating the vibration at any location on a flexible structure mounted on a vibrating flexible base is considered using a Kalman-based active feedforward-feedback controller (KAFB) with non-collocated sensors and actuators. The control strategy developed in this study focuses on lowering the force transmitted to the structure through its vibrating elastic foundation in the presence of process and measurements noise. A state-space model of the structure is constructed from the natural frequencies and mode shapes generated via finite element modal analysis of the structure. The important aspect of the proposed control strategy is that, while it's design is based on a full order model of the physical structure (plant), its implementation is reduced to the realization of a second order estimator regardless of the order of the plant model, and with negligible effect on its accuracy and performance. Therefore, the proposed control strategy requires low computational effort, which makes it well suited for real time control applications. Another unique aspect of this control strategy is its agility and speed in compensating for any phase or magnitude mismatch between transmitted force and control force. Moreover, the stability of the control system is implicitly attained by the controllability condition posed by the Kalman filter on the model. Thus, proper choice of Kalman gains will drive the states of the structure, at the sensor location, ideally to zero. In addition to that, digital implementation of the proposed controller can be easily done considering the fact that the discrete Kalman filter is exact. Numerical simulation of the controller performance is carried out and the results are presented.

  2. Mathematical Description and Modeling of the Vibration Isolation Device with Neodymium Compensator Stiffness

    NASA Astrophysics Data System (ADS)

    Gurova, E. G.

    2017-07-01

    In this article a mathematical description of the block diagram of the vibration isolation device with stiffness compensator is given. The vibration isolation system simulation performed with different functional elements, during which operation waveforms obtained with neodymium device compensator of the stiffness. Research & Development is under the scholarship of the President of Russian Federation, order No 184 from 10th of March 2015.

  3. A novel vibration isolation system for reaction wheel on space telescopes

    NASA Astrophysics Data System (ADS)

    Zhang, Yao; Guo, Zixi; He, Huidong; Zhang, Jingrui; Liu, Min; Zhou, Zhicheng

    2014-09-01

    A reaction wheel (RW) is commonly used as an actuator for attitude control on space telescopes. The RW can also produce tonal disturbances and broadband noises when the wheel spins. In this work, a novel vibration isolation system is proposed to attenuate the disturbances caused by the RW. This novel vibration isolation system includes a multi-strut vibration isolation platform and multiple tuned-mass dampers, and each strut of the vibration isolation platform includes a negative stiffness structure in parallel with a positive stiffness structure. This study aims to validate the feasibility and effectiveness of this new vibration isolation system from a theoretical perspective. First, the integrated satellite dynamic model is constructed, including the RWs and the vibration isolation systems. Next, its frequency domain characteristics are described, and the application of the vibration isolation system for RWs is presented. Finally, the effective attenuation of RW disturbances is illustrated via the new vibration isolation system, and its safety performance is verified with numerical simulations.

  4. Optical payload isolation using the Miniature Vibration Isolation System (MVIS-II)

    NASA Astrophysics Data System (ADS)

    McMickell, M. B.; Kreider, Thom; Hansen, Eric; Davis, Torey; Gonzalez, Mario

    2007-04-01

    Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters, stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to adapt to changes in payload mass properties and geometry, through active control of a smart material. MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload geometry and mass properties with modification limited to support structures only. The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally, Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while the active piezoelectric actuator is used for enhanced low

  5. Analysis of a vibration isolation table comprising post-buckled Γ-shaped beam isolators

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Waters, T. P.

    2016-09-01

    In this paper, the static and dynamic characteristics of a nonlinear passive vibration isolation table is investigated through finite element analysis. The intended application is specifically isolation in the vertical direction where the isolator is required to be sufficiently stiff statically to bear the weight of the isolated object and soft dynamically for small oscillations about its equilibrium position. The modelled configuration consists of a rigid isolation table mounted on two Γ-shaped beam isolators which are loaded to their post-buckled state in their unstable buckling mode by the weight of the isolated mass. A nonlinear static analysis is presented to establish the negative stiffness provided by the buckled beams, and two linear springs are then added in parallel which are chosen to have just sufficient stiffness to restore stability. Modal analysis of the linearized system about its statically deformed position (1mm) gives a natural frequency of just 1Hz which is considerably lower than is achievable by a linear isolator. Motion transmissibility of the linearized system shows a non-resonant isolation region spanning two decades when the system is perfectly symmetric but additional resonance peaks appear when asymmetries are included in either the mass or stiffness distribution. Several strategies are explored for reducing the prominence of these resonances.

  6. Design of active whole-spacecraft vibration isolation based on voice-coil motor

    NASA Astrophysics Data System (ADS)

    Chi, Weichao; Cao, Dengqing; Huang, Wenhu

    2014-03-01

    In the launching process of a spacecraft, the dynamic environment is very complex, so a vibration isolator is widely used for preventing the spacecraft from being damaged. This paper focused on a whole-spacecraft vibration isolation platform with the purpose of isolating the shock and noise transmitting directly to the spacecraft in the process of launching. The isolator is designed based on a model of circular payload adapter fitting. A voice-coil motor is designed and optimized as the active control actuator to provide proper feedback force to reduce the amplitude of the vibration, and is fixed in the whole-spacecraft vibration isolation platform, with sensors collocated on one side of the voice-coil motor in the vertical direction. The LQR control strategy is designed for the preliminary model of the isolation system in the vertical direction. Numerical simulation results are given to verify the effectiveness of the proposed isolation unit consisted of the voicecoil actuators.

  7. Electromagnetically levitated vibration isolation system for the manufacturing process of silicon monocrystals

    NASA Technical Reports Server (NTRS)

    Kanemitsu, Yoichi; Watanabe, Katsuhide; Yano, Kenichi; Mizuno, Takayuki

    1994-01-01

    This paper introduces a study on an Electromagnetically Levitated Vibration Isolation System (ELVIS) for isolation control of large-scale vibration. This system features no mechanical contact between the isolation table and the installation floor, using a total of four electromagnetic actuators which generate magnetic levitation force in the vertical and horizontal directions. The configuration of the magnet for the vertical direction is designed to prevent any generation of restoring vibratory force in the horizontal direction. The isolation system is set so that vibration control effects due to small earthquakes can be regulated to below 5(gal) versus horizontal vibration levels of the installation floor of up t 25(gal), and those in the horizontal relative displacement of up to 30 (mm) between the floor and levitated isolation table. In particular, studies on the relative displacement between the installation floor and the levitated isolation table have been made for vibration control in the horizontal direction. In case of small-scale earthquakes (Taft wave scaled: max. 25 gal), the present system has been confirmed to achieve a vibration isolation to a level below 5 gal. The vibration transmission ratio of below 1/10 has been achieved versus continuous micro-vibration (approx. one gal) in the horizontal direction on the installation floor.

  8. Effects of Partial Vibration on Morphological Changes in Bone and Surrounding Muscle of Rats Under Microgravity Condition: Comparative Study by Gender

    NASA Astrophysics Data System (ADS)

    Park, Ji Hyung; Seo, Dong-Hyun; Cho, Seungkwan; Kim, Seo-Hyun; Eom, Sinae; Kim, Han Sung

    2015-09-01

    Musculoskeletal disorders during and after spaceflight are considered as a serious health issue. In space, weight-bearing exercise recognized as the main countermeasure to bone loss, since many anti-resorptive medications have not yet been approved for spaceflight or have been unsuccessful in their limited application. We need to investigate a complementary or alternative way to prevent bone loss and muscle atrophy resulting from microgravity condition. Partial vibration was chosen because it is one of the most feasible ways to adopt safely and effectively. Moreover, although the influence of hind-limb suspension has been studied in both male and female rodents, only rarely are both genders evaluated in the same study. Thus, to further extend our knowledge, the present study performed comparative analysis between genders. A total of 36 12-week-old male and female Sprague-Dawley rats were used and were randomly assigned to control (CON), hind-limb suspension without vibration stimulus (HS), and hind-limb suspension with vibration stimulus (HV) groups. Hind-limb suspension has led to increasing the rate of bone loss and muscle atrophy regardless of gender. The rates of bone loss in male group obviously increased than that of female group. All structural parameters were showed significant difference between HS and HV ( p < 0.05) in male group whereas there are no significant differences in female group. In female, the muscle volume with treatment of partial vibration stimulus significantly increased which compared with that of hind-limb suspension ( p < 0.05) whereas there are no significant differences in male group. Thus partial vibration could prevent bone loss of tibia in males and muscle atrophy in females induced by hind-limb suspension. In other words, partial vibration has positive effects on damaged musculoskeletal tissues that differ based on gender.

  9. Multi-sensor control for 6-axis active vibration isolation

    NASA Astrophysics Data System (ADS)

    Thayer, Douglas Gary

    The goal of this research is to look at the two different parts of the challenge of active vibration isolation. First is the hardware that will be used to accomplish the task and improve performance. The cubic hexapod, or Stewart platform, has become a popular solution to the problem because of its ability to provide 6-axis vibration isolation with a relatively simple configuration. A number of these hexapods have been constructed at different research facilities around the country to address different missions, each with their own approach. Hood Technology Corporation and the University of Washington took the lessons learned from these designs and developed a new hexapod that addresses the requirements of the Jet Propulsion Laboratory's planned space borne interferometry missions. This system has unique mechanical design details and is built with 4 sensors in each strut. This, along with a real time computer to implement controllers, allows for a great deal of flexibility in controller design and research into sensor selection. Other unique design features include a very soft axial stiffness, a custom designed voice coil actuator with a large displacement capability and elastomeric flexures both for guiding the actuator and providing pivot points on each strut. The second part, and the primary area of this research, is to examine multi-sensor control strategies in an effort to improve the performance of the controllers, their stability and/or how implementable they are. Up to this point, the primary method of control for systems of this type has been classical, designing single-input, single output controller loops to be closed around each strut. But because of the geometry of the hexapod and the different problems that can occur with some sensors, the classical approach is limited in what it can accomplish. This research shows the benefits to be gained by going to a multiple sensor controller and implementing controllers that are designed using a frequency

  10. Proceedings of the Twentieth International Microgravity Measurements Group Meeting

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard (Compiler)

    2001-01-01

    The International Microgravity Measurements Group annual meetings provide a forum for an exchange of information and ideas about various aspects of microgravity acceleration research in international microgravity research programs. These meetings are sponsored by the PI Microgravity Services (PIMS) project at the NASA Glenn Research Center. The twentieth MGMG meeting was held 7-9 August 2001 at the Hilton Garden Inn Hotel in Cleveland, Ohio. The 35 attendees represented NASA, other space agencies, universities, and commercial companies; eight of the attendees were international representatives from Canada, Germany, Italy, Japan, and Russia. Seventeen presentations were made on a variety of microgravity environment topics including the International Space Station (ISS), acceleration measurement and analysis results, science effects from microgravity accelerations, vibration isolation, free flyer satellites, ground testing, and microgravity outreach. Two working sessions were included in which a demonstration of ISS acceleration data processing and analyses were performed with audience participation. Contained within the minutes is the conference agenda which indicates each speaker, the title of their presentation, and the actual time of their presentation. The minutes also include the charts for each presentation which indicate the author's name(s) and affiliation. In some cases, a separate written report was submitted and has been included here.

  11. A programmable broadband low frequency active vibration isolation system for atom interferometry

    NASA Astrophysics Data System (ADS)

    Tang, Biao; Zhou, Lin; Xiong, Zongyuan; Wang, Jin; Zhan, Mingsheng

    2014-09-01

    Vibration isolation at low frequency is important for some precision measurement experiments that use atom interferometry. To decrease the vibrational noise caused by the reflecting mirror of Raman beams in atom interferometry, we designed and demonstrated a compact stable active low frequency vibration isolation system. In this system, a digital control subsystem is used to process and feedback the vibration measured by a seismometer. A voice coil actuator is used to control and cancel the motion of a commercial passive vibration isolation platform. With the help of field programmable gate array-based control subsystem, the vibration isolation system performed flexibly and accurately. When the feedback is on, the intrinsic resonance frequency of the system will change from 0.8 Hz to about 0.015 Hz. The vertical vibration (0.01-10 Hz) measured by the in-loop seismometer is reduced by an additional factor of up to 500 on the basis of a passive vibration isolation platform, and we have proved the performance by adding an additional seismometer as well as applying it in the atom interferometry experiment.

  12. A programmable broadband low frequency active vibration isolation system for atom interferometry.

    PubMed

    Tang, Biao; Zhou, Lin; Xiong, Zongyuan; Wang, Jin; Zhan, Mingsheng

    2014-09-01

    Vibration isolation at low frequency is important for some precision measurement experiments that use atom interferometry. To decrease the vibrational noise caused by the reflecting mirror of Raman beams in atom interferometry, we designed and demonstrated a compact stable active low frequency vibration isolation system. In this system, a digital control subsystem is used to process and feedback the vibration measured by a seismometer. A voice coil actuator is used to control and cancel the motion of a commercial passive vibration isolation platform. With the help of field programmable gate array-based control subsystem, the vibration isolation system performed flexibly and accurately. When the feedback is on, the intrinsic resonance frequency of the system will change from 0.8 Hz to about 0.015 Hz. The vertical vibration (0.01-10 Hz) measured by the in-loop seismometer is reduced by an additional factor of up to 500 on the basis of a passive vibration isolation platform, and we have proved the performance by adding an additional seismometer as well as applying it in the atom interferometry experiment.

  13. Active automotive engine vibration isolation using feedback control

    NASA Astrophysics Data System (ADS)

    Olsson, Claes

    2006-06-01

    Large frequency band feedback active automotive engine vibration isolation is considered. A MIMO (multi-input multi-output) controller design for an active engine suspension system has been performed making use of a virtual development environment for design, analysis, and co-simulation based closed-loop verification. Utilising relevant control object dynamic modelling, this design strategy provides a powerful opportunity to deal with various plant dynamics, such as structural flexibility and nonlinear characteristics where the main objective is to approach the actual physical characteristics for design and verification in early design phases where no prototypes are yet physically available. H2 loop shaping technique proves to be powerful when achieving the desired frequency dependent loop gain while ensuring closed-loop stability. However, to achieve closed-loop stability two kinds of nonlinearities have to be taken into account. Those are nonlinear material characteristics of the engine mounts and large angular engine displacements. It is demonstrated how the adopted design strategy facilitates the investigation of the latter nonlinearity's impact on closed-loop characteristics. To deal with the nonlinearities, gain scheduling has been used.

  14. Comparison of Two Conceptions of the Vibration Isolation Systems

    NASA Astrophysics Data System (ADS)

    Šklíba, Jan; Sivčák, M.; Čižmár, J.

    The sprung stretcher of a ground ambulance litter as the space conducting mechanism with three degrees of freedom. The first degree is determined to compensate the vertical translations of a carriage, the second and third to compensate both horizontal rotations (so called pitching and rolling). The first degree is realized with scissor or with parallelogram, on the upper base on which the double Cardane suspension is placed (as the second and third degree). The second Cardane frame is connected with an own stretcher. The vibration isolation is realized with controlled pneumatic springs. Their control has two sensing units: sensor of the relative position of the upper and lower base and sensor of the absolute angle deflection of the second Cardane frame from an horizontal plane (double electrolytic level). This level is modeled as a spherical pendulum (on the base of its identified characteristics). There was analyzed this dynamic system with five degrees of freedom. The analyze of two conceptions demonstrates that the scissor mechanism is for the complete space mechanism more useful than the parallelogram.

  15. Effect of vertical active vibration isolation on tracking performance and on ride qualities

    NASA Technical Reports Server (NTRS)

    Dimasi, F. P.; Allen, R. E.; Calcaterra, P. C.

    1972-01-01

    An investigation to determine the effect on pilot performance and comfort of an active vibration isolation system for a commercial transport pilot seat is reported. The test setup consisted of: a hydraulic shaker which produced random vertical vibration inputs; the active vibration isolation system; the pilot seat; the pilot control wheel and column; the side-arm controller; and a two-axis compensatory tracking task. The effects of various degrees of pilot isolation on short-term (two-minute) tracking performance and comfort were determined.

  16. Prototyping a compact system for active vibration isolation using piezoelectric sensors and actuators.

    PubMed

    Shen, Hui; Wang, Chun; Li, Liufeng; Chen, Lisheng

    2013-05-01

    Being small in size and weight, piezoelectric transducers hold unique positions in vibration sensing and control. Here, we explore the possibility of building a compact vibration isolation system using piezoelectric sensors and actuators. The mechanical resonances of a piezoelectric actuator around a few kHz are suppressed by an order of magnitude via electrical damping, which improves the high-frequency response. Working with a strain gauge located on the piezoelectric actuator, an auxiliary control loop eliminates the drift associated with a large servo gain at dc. Following this approach, we design, optimize, and experimentally verify the loop responses using frequency domain analysis. The vibration isolation between 1 Hz and 200 Hz is achieved and the attenuation peaks at 60 near vibration frequency of 20 Hz. Restrictions and potentials for extending the isolation to lower vibration frequencies are discussed.

  17. Development of hybrid type pneumatic vibration isolation table by piezo-stack actuator and filtered-X LMS algorithm

    NASA Astrophysics Data System (ADS)

    Shin, Yun-ho; Jang, Dong-doo; Moon, Seok-jun; Jung, Hyung-Jo; Moon, Yeong-jong; Song, Chang-kyu

    2011-04-01

    Recently, vibration requirements are getting stricter as precise equipments need more improved vibration environment to realize their powerful performance. Though the passive pneumatic vibration isolation tables are frequently used to satisfy the rigorous vibration requirements, the specific vibration problem, especially continuous sinusoidal or periodic vibration induced by a rotor system of other precise equipment, a thermo-hygrostat or a ventilation system, is still left. In this research, the application procedure of Filtered-X LMS algorithm to pneumatic vibration isolation table with piezo-stack actuators is proposed to enhance the isolation performance for the continuous sinusoidal or periodic vibration. In addition, the experimental results to show the isolation performance of proposed system are also presented together with the isolation performance of passive pneumatic isolation table.

  18. Development of a multi-degree-of-freedom micropositioning, vibration isolation and vibration suppression system

    NASA Astrophysics Data System (ADS)

    Jaensch, M.; Lampérth, M. U.

    2007-04-01

    This paper describes the design and performance testing of a micropositioning, vibration isolation and suppression system, which can be used to position a piece of equipment with sub-micrometre accuracy and stabilize it against various types of external disturbance. The presented demonstrator was designed as part of a novel extremely open pre-polarization magnetic resonance imaging (MRI) scanner. The active control system utilizes six piezoelectric actuators, wide-bandwidth optical fibre displacement sensors and a very fast digital field programmable gate array (FPGA) controller. A PID feedback control algorithm with emphasis on a very high level of integral gain is employed. Due to the high external forces expected, the whole structure is designed to be as stiff as possible, including a novel hard mount approach with parallel passive damping for the suspension of the payload. The performance of the system is studied theoretically and experimentally. The sensitive equipment can be positioned in six degrees of freedom with an accuracy of ± 0.2 µm. External disturbances acting on the support structure or the equipment itself are attenuated in three degrees of freedom by more than -20 dB within a bandwidth of 0-200 Hz. Excellent impulse rejection and input tracking are demonstrated as well.

  19. A New Ultra-low Frequency Passive Vertical Vibration Isolation System

    NASA Astrophysics Data System (ADS)

    Zhao, Peng-Fei; Huang, Yu-Ying; Tang, Meng-Xi

    2002-02-01

    A new ultra-low frequency passive vertical vibration isolation system is constructed by connecting the torsion spring isolator with a reverse pendulum. The theoretical analysis shows that the new system can achieve a much longer resonant period and have a smaller size than the current torsion spring isolators with the same geometric parameters.

  20. ISS Expedition 18 Fincke on Cycle Egrometer with Vibration Isolation System (CEVIS)

    NASA Image and Video Library

    2008-10-29

    ISS018-E-005710 (29 Oct. 2008) --- Astronaut Michael Fincke, Expedition 18 commander, exercises on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station.

  1. Vibration isolation of automotive vehicle engine using periodic mounting systems

    NASA Astrophysics Data System (ADS)

    Asiri, S.

    2005-05-01

    Customer awareness and sensitivity to noise and vibration levels have been raised through increasing television advertisement, in which the vehicle noise and vibration performance is used as the main market differentiation. This awareness has caused the transportation industry to regard noise and vibration as important criteria for improving market shares. One industry that tends to be in the forefront of the technology to reduce the levels of noise and vibration is the automobile industry. Hence, it is of practical interest to reduce the vibrations induced structural responses. The automotive vehicle engine is the main source of mechanical vibrations of automobiles. The engine is vulnerable to the dynamic action caused by engine disturbance force in various speed ranges. The vibrations of the automotive vehicle engines may cause structural failure, malfunction of other parts, or discomfort to passengers because of high level noise and vibrations. The mounts of the engines act as the transmission paths of the vibrations transmitted from the excitation sources to the body of the vehicle and passengers. Therefore, proper design and control of these mounts are essential to the attenuation of the vibration of platform structures. To improve vibration resistant capacities of engine mounting systems, vibration control techniques may be used. For instance, some passive and semi-active dissipation devices may be installed at mounts to enhance vibration energy absorbing capacity. In the proposed study, a radically different concept is presented whereby periodic mounts are considered because these mounts exhibit unique dynamic characteristics that make them act as mechanical filters for wave propagation. As a result, waves can propagate along the periodic mounts only within specific frequency bands called the "Pass Bands" and wave propagation is completely blocked within other frequency bands called the "Stop Bands". The experimental arrangements, including the design of

  2. Description of the traction characteristics of the neodymium compensators of the automatic vibration isolations

    NASA Astrophysics Data System (ADS)

    Gurova, E. G.; Panchenko, Y. V.; Gurov, M. G.

    2016-04-01

    In this paper the method of calculation of neodymium magnets was presented. The calculation of the neodymium magnets characteristics and stiffness correctors of the vibration isolator according to the requirements for vibration isolation devices with stiffness compensators was performed. This research has been performed with the support of the President scholarship for young scientists, order No. 184 of Ministry of education and science of the Russian Federation of the 10th of March 2015.

  3. Active vibration isolation of macro-micro motion stage disturbances using a floating stator platform

    NASA Astrophysics Data System (ADS)

    Zhang, Lufan; Long, Zhili; Cai, Jiandong; Liu, Yang; Fang, Jiwen; Wang, Michael Yu

    2015-10-01

    Macro-micro motion stage is mainly applied in microelectronics manufacturing to realize a high-acceleration, high-speed and nano-positioning motion. The high acceleration and nano-positioning accuracy would be influenced by the vibration of the motion stage. In the paper, a concept of floating stage is introduced in the macro-micro motion for isolating vibration disturbances. The design model of the floating stage is established and its theoretical analyses including natural frequency, transient and frequency response analyses are investigated, in order to demonstrate the feasibility of the floating stator platform as a vibration isolator for the macro-micro motion stage. Moreover, an optimal design of the floating stator is conducted and then verified by experiments. In order to characterize and quantify the performance of isolation obtained from the traditional fixed stator and the floating stator, the acceleration responses at different accelerations, speeds and displacements are measured in x, y and z directions. The theoretical and experimental analyses in time and frequency domains indicate that the floating stator platform is effective to actively isolate the vibration in the macro-micro motion stage. In macro-micro motion stage, high acceleration motion is provided by VCM. Vibration is induced from VCM, that is, VCM is a source system, the vibration response or force is felt by a receiver system. Generally, VCM is fixed on the base, which means that the base is the receiver system which absorbs or transfers the vibration. However, the vibration cannot completely disappear and the base vibration is inevitable. In the paper, a floated stator platform as isolation system is developed to decrease or isolate vibration between VCM and base. The floated stator platform consists of damper, stopper, floated lock, spring, limiter, sub base, etc. Unlike the traditional stator of VCM fixed on the base, the floated stator can be moved on the linear guide under vibration

  4. An adaptive left-right eigenvector evolution algorithm for vibration isolation control

    NASA Astrophysics Data System (ADS)

    Wu, T. Y.

    2009-11-01

    The purpose of this research is to investigate the feasibility of utilizing an adaptive left and right eigenvector evolution (ALREE) algorithm for active vibration isolation. As depicted in the previous paper presented by Wu and Wang (2008 Smart Mater. Struct. 17 015048), the structural vibration behavior depends on both the disturbance rejection capability and mode shape distributions, which correspond to the left and right eigenvector distributions of the system, respectively. In this paper, a novel adaptive evolution algorithm is developed for finding the optimal combination of left-right eigenvectors of the vibration isolator, which is an improvement over the simultaneous left-right eigenvector assignment (SLREA) method proposed by Wu and Wang (2008 Smart Mater. Struct. 17 015048). The isolation performance index used in the proposed algorithm is defined by combining the orthogonality index of left eigenvectors and the modal energy ratio index of right eigenvectors. Through the proposed ALREE algorithm, both the left and right eigenvectors evolve such that the isolation performance index decreases, and therefore one can find the optimal combination of left-right eigenvectors of the closed-loop system for vibration isolation purposes. The optimal combination of left-right eigenvectors is then synthesized to determine the feedback gain matrix of the closed-loop system. The result of the active isolation control shows that the proposed method can be utilized to improve the vibration isolation performance compared with the previous approaches.

  5. Vibration isolation for launch of a space station orbital replacement unit

    NASA Astrophysics Data System (ADS)

    Maly, Joseph R.; Pendleton, Scott C.; James, George H., III; Mimovich, Mark

    2004-07-01

    Delivery of Orbital Replacement Units (ORUs) to the International Space Station (ISS) and other on-orbit destinations is an important component of the space program. ORUs are integrated on orbit with space assets to maintain and upgrade functionality. For ORUs comprised of sensitive equipment, the dynamic launch environment drives design and testing requirements, and high frequency random vibrations are generally the cause for failure. Vibration isolation can mitigate the structure-borne vibration environment during launch, and hardware has been developed that can provide a reduced environment for current and future launch environments. Random vibration testing of one ORU to equivalent Space Shuttle launch levels revealed that its qualification and acceptance requirements were exceeded. An isolation system was designed to mitigate the structure-borne launch vibration environment. To protect this ORU, the random vibration levels at 50 Hz must be attenuated by a factor of two and those at higher frequencies even more. Design load factors for Shuttle launch are high, so a metallic load path is needed to maintain strength margins. Isolation system design was performed using a finite element model of the ORU on its carrier with representative disturbance inputs. Iterations on the model led to an optimized design based on flight-proven SoftRide MultiFlex isolators. Component testing has been performed on prototype isolators to validate analytical predictions.

  6. Integrated framework for jitter analysis combining disturbance, structure, vibration isolator and optical model

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Oen; Yoon, Jae-San; Han, Jae-Hung

    2012-04-01

    Micro-vibration induced by actuating components of the satellite can severely degrade the optical performance of high precision observation satellites. In this paper, an integrated analysis framework combining disturbance, structure, vibration isolator and optical system model is developed for evaluating the performance of optical payloads in the presence of micro-vibration, and the effectiveness of using a vibration isolator for performance enhancement. Reaction wheel generated disturbance, usually the largest anticipated disturbance, is modeled including the disturbances' interaction with the structural modes of the wheel. For structure modeling, a finite element program is used to solve for eigenvalues and eigenvectors of a structure model which are then used to create a state space model in modal form. A vibration isolator model capturing dynamics of an active isolator utilizing piezoelectric based actuator and load cell for feedback control is included to reduce the transmission of reaction wheel disturbances to the base structure. Dynamic response of the structure to reaction wheel disturbances is calculated with and without vibration isolator. The resulting jitter is used to obtain modulation transfer function (MTF) of diffraction limited optical system model, and the obtained MTF is used as spatial frequency filter for image simulation.

  7. Design and analysis of an intelligent vibration isolation platform for reaction/momentum wheel assemblies

    NASA Astrophysics Data System (ADS)

    Zhou, Wei-Yong; Li, Dong-Xu

    2012-06-01

    This study focuses on design and analysis of an intelligent vibration isolation platform for reaction wheel assemblies (RWAs) and momentum wheel assemblies (MWAs). A passive platform consisting of four folded beams is designed and analysed for MWAs. A simple and effective mathematical model is developed for the system consisting of the platform and MWAs, and this model is used to investigate the passive vibration isolation performance. Further development is performed to produce an intelligent platform for RWAs, with piezoelectric sensors and actuators bonded to the vertical beams. The flywheel imbalance and impulse load are assumed to be input disturbances for the investigation of the active vibration isolation performance by the finite element method (FEM). The simulation results show that the passive vibration isolation platform is particularly effective for the suppression of a high frequency range vibration for MWAs, and the intelligent platform using velocity feedback control effectively attenuates the dynamic amplification of amplitude at resonance for RWAs. Thus, it is concluded that the passive platform can be used as a vibration isolation platform for MWAs and that the intelligent one can be used for RWAs.

  8. Vibration Isolation for Launch of a Space Station Orbital Replacement Unit

    NASA Technical Reports Server (NTRS)

    Maly, Joseph R.; Sills, Joel W., Jr.; Pendleton, Scott C.; James, George H., III; Mimovich, Mark

    2004-01-01

    Delivery of Orbital Replacement Units (ORUs) to on-orbit destinations such a the International Space Station (ISS) and the Hubble Space Telescope is an important component of the space program. ORUs are integrated on orbit with space assets to maintain and upgrade functionality. For ORUs comprised of sensitive equipment, the dynamic launch environment drives design and testing requirements, and high frequency random vibrations are generally the cause for failure. Vibration isolation can mitigate the structure-borne vibration environment during launch, and hardware has been developed that can provide a reduced environment for current and future launch environments. Random vibration testing of one ORU to equivalent Space Shuttle launch levels revealed that its qualification and acceptance requirements were exceeded. An isolation system was designed to mitigate the structure-borne launch vibration environment. To protect this ORU, the random vibration levels at 50 Hz must be attenuated by a factor of two and those at higher frequencies even more. Design load factors for Shuttle launch are high, so a metallic load path is needed to maintain strength margins. Isolation system design was performed using a finite element model of the ORU on its carrier with representative disturbance inputs. Iterations on the modelled to an optimized design based on flight proven SoftRide MultiFlex isolators. Component testing has been performed on prototype isolators to validate analytical predictions.

  9. Seismic shock and vibration isolation 1995. Part I: Theory, analysis, and testing

    SciTech Connect

    Mok, G.C.; Chung, H.H.

    1995-07-11

    Two basic engineering strategies for the protection of equipment and structures from damages caused by seismic shock and vibration loadings are, namely, strengthening and isolation. They work on almost totally different principles; the strengthening strategy aims primarily at increasing the capacity or the ability of the structure to withstand the dynamic loading by incorporating additional structural materials and components, while the isolation strategy focuses on reducing the demand or the transmitted loading on the structure by adding an isolator or isolation system between the structure and the source of the loading. The isolation strategy is often used for filtering out unwanted vibrations and noises. In practice, the isolation strategy has the advantage of not depending on alterations to the isolated structure and is often the preferred method for applications in equipment and in some structures.

  10. A new vibration isolation bed stage with magnetorheological dampers for ambulance vehicles

    NASA Astrophysics Data System (ADS)

    Chae, Hee Dong; Choi, Seung-Bok

    2015-01-01

    The vibration experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from providing emergency care. In this study, with the goal of resolving this problem, a new vibration isolation bed stage associated with magnetorheological (MR) dampers is proposed to ensure ride quality as well as better care for the patient while he/she is being transported. The bed stage proposed in this work can isolate vibrations in the vertical, rolling and pitching directions to reflect the reality that occurs in the ambulance. Firstly, an appropriate-sized MR damper is designed based on the field-dependent rheological properties of MR fluid, and the damping force characteristics of a MR damper are evaluated as a function of the current. A mechanical model of the proposed vibration isolation bed stage is then established to derive the governing equations of motion. Subsequently, a sliding mode controller is formulated to control the vibrations caused from the imposed excitation signals; those signals are directly measured using a real ambulance subjected to bump-and-curve road conditions. Using the controller based on the dynamic motion of the bed stage, the vibration control performance is evaluated in both the vertical and pitch directions. It is demonstrated that the magnitude of the vibration in the patient compartment of the ambulance can be significantly reduced by applying an input current to the MR dampers installed for the new bed stage.

  11. Analysis of Design Parameters Effects on Vibration Characteristics of Fluidlastic Isolators

    NASA Astrophysics Data System (ADS)

    Deng, Jing-hui; Cheng, Qi-you

    2017-07-01

    The control of vibration in helicopters which consists of reducing vibration levels below the acceptable limit is one of the key problems. The fluidlastic isolators become more and more widely used because the fluids are non-toxic, non-corrosive, nonflammable, and compatible with most elastomers and adhesives. In the field of the fluidlastic isolators design, the selection of design parameters is very important to obtain efficient vibration-suppressed. Aiming at getting the effect of design parameters on the property of fluidlastic isolator, a dynamic equation is set up based on the theory of dynamics. And the dynamic analysis is carried out. The influences of design parameters on the property of fluidlastic isolator are calculated. Dynamic analysis results have shown that fluidlastic isolator can reduce the vibration effectively. Analysis results also showed that the design parameters such as the fluid density, viscosity coefficient, stiffness (K1 and K2) and loss coefficient have obvious influence on the performance of isolator. The efficient vibration-suppressed can be obtained by the design optimization of parameters.

  12. Study of providing omnidirectional vibration isolation to entire space shuttle payload packages

    NASA Technical Reports Server (NTRS)

    Chang, C. S.; Robinson, G. D.; Weber, D. E.

    1974-01-01

    Techniques to provide omnidirectional vibration isolation for a space shuttle payload package were investigated via a reduced-scale model. Development, design, fabrication, assembly and test evaluation of a 0.125-scale isolation model are described. Final drawings for fabricated mechanical components are identified, and prints of all drawings are included.

  13. A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

    NASA Astrophysics Data System (ADS)

    Yang, J.; Sun, S. S.; Du, H.; Li, W. H.; Alici, G.; Deng, H. X.

    2014-10-01

    Magneto-rheological elastomers (MREs) have attracted notable credits in the development of smart isolators and absorbers due to their controllable stiffness and damping properties. For the purpose of mitigating unwanted structural and/or machinery vibrations, the traditional MRE-based isolators have been generally proven effective because the MR effect can increase the stiffness when the magnetic field is strengthened. This study presents a novel MRE isolator that experienced reduced stiffness when the applied current was increased. This innovative work was accomplished by applying a hybrid magnet (electromagnet and permanent magnets) onto a multilayered MRE structure. To characterise this negative changing stiffness concept, a multilayered MRE isolator with a hybrid magnet was first designed, fabricated and then tested to measure its properties. An obvious reduction of the effective stiffness and natural frequency of the proposed MRE isolator occurred when the current was continuously adjusted. This device could also work as a conventional MRE isolator as its effective stiffness and natural frequency also increased when a negative current was applied. Further testing was carried out on a one-degree-of-freedom system to assess how effectively this device could isolate vibration. In this experiment, two cases were considered; in each case, the vibration of the primary system was obviously attenuated under ON-OFF control logic, thus demonstrating the feasibility of this novel design as an alternative adaptive vibration isolator.

  14. A voice coil actuator driven active vibration isolation system with the consideration of flexible modes

    NASA Astrophysics Data System (ADS)

    Park, Kyihwan; Choi, Dongyoub; Ozer, Abdullah; Kim, Sangyoo; Lee, Yongkwan; Joo, Dongik

    2008-06-01

    We develop a four-mount active vibration isolation system (AVIS) using voice coil actuators. The flexible body modes in the upper plate of the AVIS can cause an instability problem due to control signal whose frequency is close to the resonant frequency of the flexible modes. The loop shaping technique is applied to reduce the amplitude of the control signal. We investigate the performances of the active vibration isolation system proposed in the word in the time domain and frequency domain by comparing to the passive isolation system.

  15. A voice coil actuator driven active vibration isolation system with the consideration of flexible modes.

    PubMed

    Park, Kyihwan; Choi, Dongyoub; Ozer, Abdullah; Kim, Sangyoo; Lee, Yongkwan; Joo, Dongik

    2008-06-01

    We develop a four-mount active vibration isolation system (AVIS) using voice coil actuators. The flexible body modes in the upper plate of the AVIS can cause an instability problem due to control signal whose frequency is close to the resonant frequency of the flexible modes. The loop shaping technique is applied to reduce the amplitude of the control signal. We investigate the performances of the active vibration isolation system proposed in the word in the time domain and frequency domain by comparing to the passive isolation system.

  16. Active and passive vibration isolation in piezoelectric phononic rods with external voltage excitation

    NASA Astrophysics Data System (ADS)

    Zhang, Qicheng; Lan, Yu; Lu, Wei; Wang, Shuai

    2017-05-01

    Active piezoelectric materials are applied to one-dimensional phononic crystals, for the control of longitudinal vibration propagation both in active and passive modes. Based on the electromechanical coupling between the acoustical vibration and electric field, the electromechanical equivalent method is taken to theoretically predict the transmission spectrum of the longitudinal vibration. It is shown that the phononic rod can suppress the vibration efficiently at the frequencies of interest, by actively optimizing the motions of piezoelectric elements. In an illustrated phononic rod of 11.2cm long, active tunable isolations of more than 20dB at low frequencies (500Hz-14kHz) are generated by controlling the excitation voltages of piezoelectric elements. Meanwhile, passive fixed isolation at high frequencies (14k-63kHz) are presented by its periodicity characteristics. Finite element simulations and vibration experiments on the rod demonstrate the effectiveness of the approach in terms of its vibration isolation capabilities and tunable characteristics. This phononic rod can be manufactured easily and provides numerous potential applications in designing isolation mounts and platforms.

  17. Application of a load-bearing passive and active vibration isolation system in hydraulic drives

    NASA Astrophysics Data System (ADS)

    Unruh, Oliver; Haase, Thomas; Pohl, Martin

    2016-09-01

    Hydraulic drives are widely used in many engineering applications due to their high power to weight ratio. The high power output of the hydraulic drives produces high static and dynamic reaction forces and moments which must be carried by the mounts and the surrounding structure. A drawback of hydraulic drives based on rotating pistons consists in multi-tonal disturbances which propagate through the mounts and the load bearing structure and produce structure borne sound at the surrounding structures and cavities. One possible approach to overcome this drawback is to use an optimised mounting, which combines vibration isolation in the main disturbance direction with the capability to carry the reaction forces and moments. This paper presents an experimental study, which addresses the vibration isolation performance of an optimised mounting. A dummy hydraulic drive is attached to a generic surrounding structure with optimised mounting and excited by multiple shakers. In order to improve the performance of the passive vibration isolation system, piezoelectric transducers are applied on the mounting and integrated into a feed-forward control loop. It is shown that the optimised mounting of the hydraulic drive decreases the vibration transmission to the surrounding structure by 8 dB. The presented study also reveals that the use of the active control system leads to a further decrease of vibration transmission of up to 14 dB and also allows an improvement of the vibration isolation in an additional degree of freedom and higher harmonic frequencies.

  18. Passive vibration isolation of reaction wheel disturbances using a low frequency flexible space platform

    NASA Astrophysics Data System (ADS)

    Kamesh, D.; Pandiyan, R.; Ghosal, Ashitava

    2012-03-01

    Reaction wheel assemblies (RWAs) are momentum exchange devices used in fine pointing control of spacecrafts. Even though the spinning rotor of the reaction wheel is precisely balanced to minimize emitted vibration due to static and dynamic imbalances, precision instrument payloads placed in the neighborhood can always be severely impacted by residual vibration forces emitted by reaction wheel assemblies. The reduction of the vibration level at sensitive payloads can be achieved by placing the RWA on appropriate mountings. A low frequency flexible space platform consisting of folded continuous beams has been designed to serve as a mount for isolating a disturbance source in precision payloads equipped spacecrafts. Analytical and experimental investigations have been carried out to test the usefulness of the low frequency flexible platform as a vibration isolator for RWAs. Measurements and tests have been conducted at varying wheel speeds, to quantify and characterize the amount of isolation obtained from the reaction wheel generated vibration. These tests are further extended to other variants of similar design in order to bring out the best isolation for given disturbance loads. Both time and frequency domain analysis of test data show that the flexible beam platform as a mount for reaction wheels is quite effective and can be used in spacecrafts for passive vibration control.

  19. Utilizing Controlled Vibrations in a Microgravity Environment to Understand and Promote Microstructural Homogeneity During Floating-Zone Crystal Growth

    NASA Technical Reports Server (NTRS)

    Anilkumar, A. V.; Bhowmick, J.; Grugel, R. N.

    2001-01-01

    Our previous experiments with NaNO3 float-zones revealed that steady thermocapillary flow can be balanced/offset by the controlled surface streaming flow induced by end-wall vibration. In the current experiments we are examining the effects of streaming flow on steadying/stabilizing nonsteady thermocapillary flow in such zones. To this effect we have set up a controlled NaNO3 half-zone experiment, where the processing parameters, like zone dimensions and temperature gradients, can be easily varied to generate nonsteady thermocapillary flows. In the present paper we present preliminary results of our investigations into stabilizing such flows by employing endwall vibration.

  20. Utilizing Controlled Vibrations in a Microgravity Environment to Understand and Promote Microstructural Homogeneity During Floating-Zone Crystal Growth

    NASA Technical Reports Server (NTRS)

    Anilkumar, A. V.; Bhowmick, J.; Grugel, R. N.

    2001-01-01

    Our previous experiments with NaNO3 float-zones revealed that steady thermocapillary flow can be balanced/offset by the controlled surface streaming flow induced by end-wall vibration. In the current experiments we are examining the effects of streaming flow on steadying/stabilizing nonsteady thermocapillary flow in such zones. To this effect we have set up a controlled NaNO3 half-zone experiment, where the processing parameters, like zone dimensions and temperature gradients, can be easily varied to generate nonsteady thermocapillary flows. In the present paper we present preliminary results of our investigations into stabilizing such flows by employing endwall vibration.

  1. Improved hybrid isolator with maglev actuator integrated in air spring for active-passive isolation of ship machinery vibration

    NASA Astrophysics Data System (ADS)

    Li, Yan; He, Lin; Shuai, Chang-geng; Wang, Chun-yu

    2017-10-01

    A hybrid isolator consisting of maglev actuator and air spring is proposed and developed for application in active-passive vibration isolation system of ship machinery. The dynamic characteristics of this hybrid isolator are analyzed and tested. The stability and adaptability of this hybrid isolator to shock and swing in the marine environment are improved by a compliant gap protection technique and a disengageable suspended structure. The functions of these new engineering designs are proved by analytical verification and experimental validation of the designed stiffness of such a hybrid isolator, and also by shock adaptability testing of the hybrid isolator. Finally, such hybrid isolators are installed in an engineering mounting loaded with a 200-kW ship diesel generator, and the broadband and low-frequency sinusoidal isolation performance is tested.

  2. Design and control of six degree-of-freedom active vibration isolation table.

    PubMed

    Hong, Jinpyo; Park, Kyihwan

    2010-03-01

    A six-axis active vibration isolation system (AVIS) is designed by using the direct driven guide and ball contact mechanisms in order to have no cross-coupling between actuators. The point contact configuration gives an advantage of having an easy assembly of eight voice coil actuators to an upper and a base plate. A voice coil actuator is used since it can provide a large displacement and sufficient bandwidth required for vibration control. The AVIS is controlled considering the effect of flexible vibration mode in the upper plate and velocity sensor dynamics. A loop shaping technique and phase margin condition are applied to design a vibration controller. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system. The scanning profiles of the specimen are compared together by using the atomic force microscope. The robustness of the AVIS is verified by showing the impulse response.

  3. Design and control of six degree-of-freedom active vibration isolation table

    NASA Astrophysics Data System (ADS)

    Hong, Jinpyo; Park, Kyihwan

    2010-03-01

    A six-axis active vibration isolation system (AVIS) is designed by using the direct driven guide and ball contact mechanisms in order to have no cross-coupling between actuators. The point contact configuration gives an advantage of having an easy assembly of eight voice coil actuators to an upper and a base plate. A voice coil actuator is used since it can provide a large displacement and sufficient bandwidth required for vibration control. The AVIS is controlled considering the effect of flexible vibration mode in the upper plate and velocity sensor dynamics. A loop shaping technique and phase margin condition are applied to design a vibration controller. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system. The scanning profiles of the specimen are compared together by using the atomic force microscope. The robustness of the AVIS is verified by showing the impulse response.

  4. Design, fabrication and testing of two electrohydraulic vibration isolation systems for helicopter environments

    NASA Technical Reports Server (NTRS)

    Allen, R. E.; Calcaterra, P. C.

    1972-01-01

    Two electrohydraulic vibration isolation systems were designed and fabricated to reduce the vertical vibrations transmitted to the XH-51N research helicopter cabin at the blade passage frequency (18 Hz) and its first harmonic (36 Hz). Hydraulic power and electrical control are provided to two separate servoactuators from a common power supply and control electronics package located behind the pilot's seat. One servoactuator is installed between the cabin and fuselage and replaces an existing passive spring. A second servoactuator is mounted between the existing seat and cabin floor. Both servoactuators incorporate a mechanical failsafe design. The control electronics circuitry provides automatic tracking of the blade passage frequency. Results of laboratory, environmental and ground vibration tests employing an XH-51A stripped down helicopter fuselage show that the active cabin isolator reduces the vertical vibrations transmitted from the fuselage attachment point to the cabin attachment point at 18 and 36 Hz (or as an alternative, 6 Hz) by better than 90 percent.

  5. Positioning and Microvibration Control by Electromagnets of an Air Spring Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Watanabe, Katsuhide; Cui, Weimin; Haga, Takahide; Kanemitsu, Yoichi; Yano, Kenichi

    1996-01-01

    Active positioning and microvibration control has been attempted by electromagnets equipped in a bellows-type, air-spring vibration isolation system. Performance tests have been carried out to study the effects. The main components of the system's isolation table were four electromagnetic actuators and controllers. The vibration isolation table was also equipped with six acceleration sensors for detecting microvibration of the table. The electromagnetic actuators were equipped with bellows-type air springs for passive support of the weight of the item placed on the table, with electromagnets for active positioning, as well as for microvibration control, and relative displacement sensors. The controller constituted a relative feedback system for positioning control and an absolute feedback system for vibration isolation control. In the performance test, a 1,490 kg load (net weight of 1,820 kg) was placed on the vibration isolation table, and both the positioning and microvibration control were carried out electromagnetically. Test results revealed that the vibration transmission was reduced by 95%.

  6. Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams.

    PubMed

    Zhang, Xiaoyong; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei; Yan, Xiaojun

    2016-06-01

    This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young's modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz-97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

  7. Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams

    SciTech Connect

    Zhang, Xiaoyong E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun E-mail: yanxiaojun@buaa.edu.cn; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei

    2016-06-15

    This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.

  8. A 6DOF passive vibration isolator using X-shape supporting structures

    NASA Astrophysics Data System (ADS)

    Wu, Zhijing; Jing, Xingjian; Sun, Bo; Li, Fengming

    2016-10-01

    A novel 6 degree of freedom (6-DOF) passive vibration isolator is studied theoretically and validated with experiments. Based on the Stewart platform configuration, the 6-DOF isolator is constructed by 6 X-shape structures as legs, which can realize very good and tunable vibration isolation performance in all 6 directions with a passive manner. The mechanic model is established for static analysis of the working range, static stiffness and loading capacity. Thereafter, the equation of motion of the isolator is derived with the Hamilton principle. The equivalent stiffness and the displacement transmissibility in the six decoupled DOFs direction are then discussed with experimental results for validation. The results reveal that (a) by designing the structure parameters, the system can possess flexible stiffness such as negative, quasi-zero and positive stiffness, (b) due to the combination of the Stewart platform and the X-shape structure, the system can have very good vibration isolation performance in all the 6 directions and in a passive manner, and (c) compared with the simplified linear-stiffness legs, the nonlinearity of the X-shape structures enhance the passive isolator to have much better vibration isolation performance.

  9. Design and optimization of voice coil actuator for six degree of freedom active vibration isolation system using Halbach magnet array.

    PubMed

    Kim, MyeongHyeon; Kim, Hyunchang; Gweon, Dae-Gab

    2012-10-01

    This paper describes the design, modeling, optimization, and validation of an active vibration isolation system using a voice coil motor. The active vibration isolating method was constructed with a passive isolator and an active isolator. A spring was used for passive isolating; an actuator was used for active isolating. The proposed active vibration isolation system (AVIS) can isolate disturbances for many kinds of instruments. Until now, developed AVIS were able to isolate a six degree-of-freedom disturbance effectively. This paper proposes the realization of such a six degree-of-freedom active vibration isolation system that can work as a bench top device for precision measuring machines such as atomic force microscope, scanning probe microscope, etc.

  10. The efficiency evaluation of support vibration isolation with mechanic inertial motion converter for vibroactive process equipment

    NASA Astrophysics Data System (ADS)

    Buryan, Yu. A.; Babichev, D. O.; Silkov, M. V.; Shtripling, L. O.; Kalashnikov, B. A.

    2017-08-01

    This research refers to the problems of processing equipment protection from vibration influence. The theory issues of vibration isolation for vibroactive objects such as engines, pumps, compressors, fans, piping, etc. are considered. The design of the perspective air spring with the parallel mounted mechanical inertial motion converter is offered. The mathematical model of the suspension, allowing selecting options to reduce the factor of the force transmission to the base in a certain frequency range is obtained.

  11. Mounting Systems for Structural Members, Fastening Assemblies Thereof, and Vibration Isolation Systems Including the Same

    NASA Technical Reports Server (NTRS)

    Young, Ken (Inventor); Hindle, Timothy (Inventor); Barber, Tim Daniel (Inventor)

    2016-01-01

    Mounting systems for structural members, fastening assemblies thereof, and vibration isolation systems including the same are provided. Mounting systems comprise a pair of mounting brackets, each clamped against a fastening assembly forming a mounting assembly. Fastening assemblies comprise a spherical rod end comprising a spherical member having a through opening and an integrally threaded shaft, first and second seating members on opposite sides of the spherical member and each having a through opening that is substantially coaxial with the spherical member through opening, and a partially threaded fastener that threadably engages each mounting bracket forming the mounting assembly. Structural members have axial end portions, each releasably coupled to a mounting bracket by the integrally threaded shaft. Axial end portions are threaded in opposite directions for permitting structural member rotation to adjust a length thereof to a substantially zero strain position. Structural members may be vibration isolator struts in vibration isolation systems.

  12. Numerical and experimental analysis of metamaterials with quasi-zero effect for vibration isolation

    NASA Astrophysics Data System (ADS)

    Anvar, Valeev

    2017-07-01

    The article is devoted to the idea of metamaterials with quasi-zero stiffness for vibration isolation. Metametarials can provide a special and unique material properties. Principles of systems with quasi-zero stiffness can be applied in this researches. Metamaterial with a low rigidity in a certain point. Consequently, low natural frequency vibration isolation and high efficiency can be obtained. Computer simulation shows a large enough margin of safety, and proves the existence of forces with quasi-zero stiffness characteristics. The calculation showed that the metamaterial has a natural frequency below 1 Hz. Experimental study shows force characteristics with quasi-zero stiffness. So, this metamaterial can be very effective and compact mean of vibration isolation

  13. Hardware interface for isolation of vibrations in flexible manipulators: Development and applications

    NASA Technical Reports Server (NTRS)

    Manouchehri, Davoud; Lindsay, Thomas; Ghosh, David

    1994-01-01

    NASA's Langley Research Center (LaRC) is addressing the problem of isolating the vibrations of the Shuttle remote manipulator system (RMS) from its end-effector and/or payload by modeling an RMS flat-floor simulator with a dynamic payload. Analysis of the model can lead to control techniques that will improve the speed, accuracy, and safety of the RMS in capturing satellites and eventually facilitate berthing with the space station. Rockwell International Corporation, also involved in vibration isolation, has developed a hardware interface unit to isolate the end-effector from the vibrations of an arm on a Shuttle robotic tile processing system (RTPS). To apply the RTPS isolation techniques to long-reach arms like the RMS, engineers have modeled the dynamics of the hardware interface unit with simulation software. By integrating the Rockwell interface model with the NASA LaRC RMS simulator model, investigators can study the use of a hardware interface to isolate dynamic payloads from the RMS. The interface unit uses both active and passive compliance and damping for vibration isolation. Thus equipped, the RMS could be used as a telemanipulator with control characteristics for capture and berthing operations. The hardware interface also has applications in industry.

  14. Active Vibration Isolation of an Unbalanced Machine Spindle

    SciTech Connect

    Hopkins, D J; Geraghty, P

    2004-08-13

    Proper configurations of controls, sensors, and metrology technologies have enabled precision turning machines to achieve nanometer positioning. However, at this level of positioning resolution, vibration sources can become a limiting factor. One of the largest sources of vibration in a turning machine may be an unbalanced rotating spindle. In this paper, a system is implemented to actively cancel spindle unbalance forces. Specifically, to attenuate the spindle housing vibration using an active vibration control system to prevent the unbalance force from disturbing the rest of the machine systems e.g., the slide servo system or the machine metrology frame. The system controls three degrees of motion. An unbalanced spindle creates a rotating force vector with a once per revolution period. The cause and size of this force is a function of the spindle, the part, the part fixturing, the part setup and the spindle speed. In addition, certain spindle speeds coupled with the size of the unbalance force may contain other harmonics that can excite machine structural resonances. The magnitude of the unbalance force increases as the square of the spindle speed. The control algorithm of this system is fully implemented on a commercially available machine tool controller and is sensitive only to unbalance induced motion. The paper describes in detail the control algorithm and how it is implemented. The system has demonstrated the ability to adapt in real time to remove the fundamental component of the unbalance force to nanometer levels. However, higher-order structural resonance components of the test bed have been observed when the system is active. The control system is stable and the voice coil (VC) excitation is harmonically clean but the high Q of the mechanical test system is apparently excited by energy leakage. Our results indicate the need to carefully examine the dynamics of any spindle system that would take advantage of this active system.

  15. Development of the Vibration Isolation System for the Advanced Resistive Exercise Device

    NASA Technical Reports Server (NTRS)

    Niebuhr, Jason H.; Hagen, Richard A.

    2011-01-01

    This paper describes the development of the Vibration Isolation System for the Advanced Resistive Exercise Device from conceptual design to lessons learned. Maintaining a micro-g environment on the International Space Station requires that experiment racks and major vibration sources be isolated. The challenge in characterizing exercise loads and testing the system in the presence of gravity led to a decision to qualify the system by analysis. Available data suggests that the system is successful in attenuating loads, yet there has been a major component failure and several procedural issues during its 3 years of operational use.

  16. Accelerated lifetime test of vibration isolator made of Metal Rubber material

    NASA Astrophysics Data System (ADS)

    Ao, Hongrui; Ma, Yong; Wang, Xianbiao; Chen, Jianye; Jiang, Hongyuan

    2017-01-01

    The Metal Rubber material (MR) is a kind of material with nonlinear damping characteristics for its application in the field of aerospace, petrochemical industry and so on. The study on the lifetime of MR material is impendent to its application in engineering. Based on the dynamic characteristic of MR, the accelerated lifetime experiments of vibration isolators made of MR working under random vibration load were conducted. The effects of structural parameters of MR components on the lifetime of isolators were studied and modelled with the fitting curves of degradation data. The lifetime prediction methods were proposed based on the models.

  17. Shape Memory Alloys for Vibration Isolation and Damping of Large-Scale Space Structures

    DTIC Science & Technology

    2007-04-01

    Research Assistants Agustin F. Maqui, Texas A&M University (BS 2010) Jack V. Heath, Texas A&M University (BS 2010) Paul F. Braden, Texas A&M...D.C., ’’Nonlinear dynamics of a SMA passive vibration isolation device," Proceedings ofSPIE Vol. 6169, SPIE, San Diego, CA, February 28-March 2, 2006... San Diego, CA, March 18-22, 2007. Machado, L.G. and Lagoudas, D.C., "Nonlinear dynamics of a SMA passive vibration isolation device," Proceedings

  18. Simultaneous supply of infinite and infinitesimal stiffness of active isolation systems that are exposed to multiple vibration sources

    NASA Astrophysics Data System (ADS)

    Kletz, Björn T.; Melcher, Jörg

    2013-04-01

    Commonly, vibration isolation systems reduce the transmissibility from seismic base vibrations to sensitive structures. To obtain a desirable low isolation frequency, vibration isolation systems are typically equipped with low stiffness interfaces between the involved structures. Strongly detrimental influences to the possible vibration reduction performance are caused by the effects of additional force disturbances that act directly on the isolated object. To protect sensitive structures from vibrations, isolation systems need to generate high flexibility against the vibrating ground. In the same time those systems need to generate high stiffness against the direct (force) disturbances as well. The technique described in this paper enables vibration reduction at such a sensitive object while seismic base and direct force disturbances are concurrently present. It is theoretically introduced and experimentally examined how the emerging conflict of simultaneous vibration isolation and energy reflection can be solved at a single isolation interface. This paper shows that even soft, adaptively altered isolation interfaces can reach these contrary goals. These interfaces are equipped with piezoelectric foil actuators to enable active control. The used active control mechanism and the very promising experimental results are highlighted in this paper.

  19. A magnetorheological fluid embedded pneumatic vibration isolator allowing independently adjustable stiffness and damping

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaocong; Jing, Xingjian; Cheng, Li

    2011-08-01

    A magnetorheological (MR) fluid embedded pneumatic vibration isolator (MrEPI) with hybrid and compact connection of pneumatic spring and MR damping elements is proposed in this study. The proposed MrEPI system allows independent nonlinear stiffness and damping control with considerable maneuverable ranges. Meanwhile, it allows convenient switching between different passive and active vibration control modes, thus providing more flexibility and versatility in applications. To demonstrate the advantageous dynamic performance of the MrEPI, a nonlinear non-dimensional dynamic model is developed with full consideration of the nonlinear elements involved. A systematic analysis is therefore conducted which can clearly reveal the influence on system output performance caused by each physically important parameter and provide a useful insight into the analysis and design of nonlinear vibration isolators with pneumatic and MR elements.

  20. On the emission of radiation by an isolated vibrating metallic mirror

    NASA Astrophysics Data System (ADS)

    Arkhipov, M. V.; Babushkin, I.; Pul'kin, N. S.; Arkhipov, R. M.; Rosanov, N. N.

    2017-04-01

    Quantum electrodynamics predicts the appearance of radiation in an empty cavity in which one of the mirrors is vibrating. It also predicts the appearance of radiation from an isolated vibrating mirror. Such effects can be described within the framework of classical electrodynamics. We present the qualitative explanation of the effect, along with the results of numerical simulation of the emission of radiation by an isolated vibrating metallic mirror, which can be induced by mirror illumination by an ultrashort pulse of light. The dynamics of conduction electrons in the metallic mirror is described by the classical Drude model. Simulation was performed for the cases of mirror illumination by either a bipolar or a unipolar pulse.