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Статті в журналах з теми "Space mechanism in-flight testing"
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Taylor, Gerald R., and Robert P. Janney. "In vivo testing confirms a blunting of the human cell-mediated immune mechanism during space flight." Journal of Leukocyte Biology 51, no. 2 (February 1992): 129–32. http://dx.doi.org/10.1002/jlb.51.2.129.
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Huber, F. W., P. D. Johnson, O. P. Sharma, J. B. Staubach, and S. W. Gaddis. "Performance Improvement Through Indexing of Turbine Airfoils: Part 1—Experimental Investigation." Journal of Turbomachinery 118, no. 4 (October 1, 1996): 630–35. http://dx.doi.org/10.1115/1.2840918.
Повний текст джерелаАнотація:
This paper describes the results of a study to determine the performance improvements achievable by circumferentially indexing successive rows of turbine stator airfoils. An experimental/analytical investigation has been completed that indicates significant stage efficiency increases can be attained through application of this airfoil clocking concept. A series of tests was conducted at the National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) to experimentally investigate stator wake clocking effects on the performance of the Space Shuttle Main Engine Alternate Fuel Turbopump Turbine Test Article. Extensive time-accurate Computational Fluid Dynamics (CFD) simulations have been completed for the test configurations. The CFD results provide insight into the performance improvement mechanism. Part one of this paper describes details of the test facility, rig geometry, instrumentation, and aerodynamic operating parameters. Results of turbine testing at the aerodynamic design point are presented for six circumferential positions of the first stage stator, along with a description of the initial CFD analyses performed for the test article. It should be noted that first vane positions 1 and 6 produced identical first to second vane indexing. Results obtained from off-design testing of the “best” and “worst” stator clocking positions, and testing over a range of Reynolds numbers are also presented. Part two of this paper describes the numerical simulations performed in support of the experimental test program described in part one. Time-accurate Navier–Stokes flow analyses have been completed for the five different turbine stator positions tested. Details of the computational procedure and results are presented. Analysis results include predictions of instantaneous and time-average midspan airfoil and turbine performance, as well as gas conditions throughout the flow field. An initial understanding of the turbine performance improvement mechanism is described.
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Z˙bikowski, Rafał, Cezary Galin´ski, and Christopher B. Pedersen. "Four-Bar Linkage Mechanism for Insectlike Flapping Wings in Hover: Concept and an Outline of Its Realization." Journal of Mechanical Design 127, no. 4 (June 27, 2005): 817–24. http://dx.doi.org/10.1115/1.1829091.
Повний текст джерелаАнотація:
This paper describes the concept of a four-bar linkage mechanism for flapping wing micro air vehicles and outlines its design, implementation, and testing. Micro air vehicles (MAVs) are defined as flying vehicles ca. 150 mm in size (handheld), weighing 50–100 g, and are developed to reconnoiter in confined spaces (inside buildings, tunnels, etc.). For this application, insectlike flapping wings are an attractive solution and, hence, the need to realize the functionality of insect flight by engineering means. Insects fly by oscillating (plunging) and rotating (pitching) their wings through large angles, while sweeping them forward and backward. During this motion, the wing tip approximately traces a figure eight and the wing changes the angle of attack (pitching) significantly. The aim of the work described here was to design and build an insectlike flapping mechanism on a 150 mm scale. The main purpose was not only to construct a test bed for aeromechanical research on hover in this mode of flight, but also to provide a precursor design for a future flapping-wing MAV. The mechanical realization was to be based on a four-bar linkage combined with a spatial articulation. Two instances of idealized figure eights were considered: (i) Bernoulli’s lemniscate and (ii) Watt’s sextic. The former was found theoretically attractive, but impractical, while the latter was both theoretically and practically feasible. This led to a combination of Watt’s straight-line mechanism with a drive train utilizing a Geneva wheel and a spatial articulation. The actual design, implementation, and testing of this concept are briefly described at the end of the paper.
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Merriam, E. G., J. E. Jones, S. P. Magleby, and L. L. Howell. "Monolithic 2 DOF fully compliant space pointing mechanism." Mechanical Sciences 4, no. 2 (December 2, 2013): 381–90. http://dx.doi.org/10.5194/ms-4-381-2013.
Повний текст джерелаАнотація:
Abstract. This paper describes the conception, modeling, and development of a fully compliant two-degree-of-freedom pointing mechanism for application in spacecraft thruster, antenna, or solar array systems. The design objectives and the advantages of a compliant solution are briefly discussed. Detailed design decisions to meet project objectives are described. Analytical and numerical models are developed and subsequently verified by prototype testing and measurements in several iterations. A final design of the 3-D printed titanium monolithic pointing mechanism is described in detail and its performance is measured.
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ZHAO Hai-bo, 赵海波, 赵伟国 ZHAO Wei-guo, 董吉洪 DONG Ji-hong, 杨维帆 YANG Wei-fan, 刘奉昌 LIU Feng-chang, 周平伟 ZHOU Ping-wei, and 姜. 萍. JIANG Ping. "Accuracy analysis and testing for secondary mirror adjusting mechanism in large space telescope." Optics and Precision Engineering 27, no. 11 (2019): 2374–83. http://dx.doi.org/10.3788/ope.20192711.2374.
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Michaels, Dan, and Alon Gany. "Modeling and testing of a tube-in-tube separation mechanism of bodies in space." Acta Astronautica 129 (December 2016): 214–22. http://dx.doi.org/10.1016/j.actaastro.2016.09.013.
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Wang, Junwei, Lei Zhang, Guohua Li, Ran Liu, Juan Ning, Xiao Han, and Xin He. "Research and Verification of Key Techniques in the Simulation of Space Extremely Rapid Decompression in Millisecond." International Journal of Aerospace Engineering 2021 (April 5, 2021): 1–11. http://dx.doi.org/10.1155/2021/6634468.
Повний текст джерелаАнотація:
The research of rapid decompression with its effect assessment and protection technology is the problem that must be faced by the future exploration projects such as near space exploration, deep space exploration, and long-term lunar or Mars base. A new reusable quick opening mechanism which can be opened in millisecond is designed to meet the testing requirement of ground simulator for extremely rapid decompression, and the testing results show that the quick opening mechanism can be opened within 0.1 s. The mathematical formulation is also developed, and the comparisons with the results from the literature demonstrate its validity. The CFD simulation and the verification system are established for the airflow in the rapid decompression process under different opening degrees. The simulation results show that the effect of the opening on the decompression process is very obvious and the decompression time corresponding to 50%, 75%, and 100% opening is 479.1 ms, 320.7 ms, and 290.1 ms, respectively. The testing results also show a consistent trend which is 583 ms, 450 ms, and 384 ms, respectively, to reach the equilibrium state.
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Hymer, W. C., R. E. Grindeland, T. Salada, P. Nye, E. J. Grossman, and P. K. Lane. "Experimental modification of rat pituitary growth hormone cell function during and after spaceflight." Journal of Applied Physiology 80, no. 3 (March 1, 1996): 955–70. http://dx.doi.org/10.1152/jappl.1996.80.3.955.
Повний текст джерелаАнотація:
Space-flown rats show a number of flight-induced changes in the structure and function of pituitary growth hormone (GH) cells after in vitro postflight testing (W. C. Hymen, R. E. Grindeland, I. Krasnov, I, Victorov, K. Motter, P. Mukherjee, K. Shellenberger, and M. Vasques. J. Appl. Physiol. 73, Suppl.: 151S-157S, 1992). To evaluate the possible effects of microgravity on growth hormone (GH) cells themselves, freshly dispersed rat anterior pituitary gland cells were seeded into vials containing serum +/- microM hydrocortisone (HC) before flight. Five different cell preparations were used: the entire mixed-cell population of various hormone-producing cell types, cells of density < 1.071 g/cm3 (band 1), cells of density > 1.071 g/cm3 (band 2), and cells prepared from either the dorsal or ventral part of the gland. Relative to ground control samples, bioactive GH released from dense cells during flight was reduced in HC-free medium but was increased in HC-containing medium. Band 1 and mixed cells usually showed opposite HC-dependent responses. Release of bioactive GH from ventral flight cells was lower; postflight responses to GH-releasing hormone challenge were reduced, and the cytoplasmic area occupied by GH in the dense cells was greater. Collectively, the data show that the chemistry and cellular makeup of the culture system modifies the response of GH cells to microgravity. As such, these cells offer a system to identify gravisensing mechanisms in secretory cells in future microgravity research.
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Konovalov, A. M., and V. I. Kugushev. "Mechanism of excitatioon of natural vibrations of fireclay products and its application in flaw detection." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 10 (November 25, 2022): 55–62. http://dx.doi.org/10.17073/1683-4518-2022-10-55-62.
Повний текст джерелаАнотація:
In this article, using the example of developing a technique for non-destructive testing of a fireclay product («asterisks») using the natural vibrations of the object of control, a mathematical model is presented that allows us to specifically describe the process of converting an external dynamic effect into the natural vibrations of the part. The peculiarity of the model is that, firstly, it is a carrier of the free energy of elastic deformation and the process of natural oscillations is formed in it. Secondly, the model is a Riemannian space in which all dynamic parameters are constant and reduced to zero, i.e. the model does not exist physically, but only as a functional space. The proposed model can serve as an effective tool for analyzing the processes observed during non-destructive testing and vibration diagnostics. Ill. 7. Ref. 22.
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Zhou, Hongming, Peiyuan Li, Longfei Wu, and Qiankun Gao. "A wavelet analysis-based matching pursuit algorithm for an accurate ultrasonic TOFD measurement." Insight - Non-Destructive Testing and Condition Monitoring 62, no. 11 (November 1, 2020): 662–68. http://dx.doi.org/10.1784/insi.2020.62.11.662.
Повний текст джерелаАнотація:
The time-of-flight diffraction (TOFD) technique is used as an important non-destructive testing method in weld integrity evaluation and failure analysis. However, an accurate measurement of the time-of-flight (TOF) has proven to be difficult due to the low time resolution of the measured signal. Conventional deconvolution techniques have been used to improve the time resolution of the signal but are not effective for ultrasonic TOFD signals because the frequency contents of the signals are non-static in space-frequency distribution. To overcome this problem, a method is proposed in this paper that estimates the TOF in two steps. In the first step, the measured signal is decomposed into a series of narrowband signals using a wavelet transform and an atom dictionary is adaptively established according to the characteristics of a selected narrowband signal. In the second step, matching pursuit (MP) is used to derive a sparse representation of the selected narrowband signal. A steel specimen with artificial defects is prepared, experiments are carried out and the results confirm the efficacy of the proposed algorithm.
Дисертації з теми "Space mechanism in-flight testing"
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Zambotti, Andrea. "Ground Testing and In-Flight Performance of a Space Mechanism." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/242871.
Повний текст джерелаАнотація:
LISA Pathfinder is a mission designed for testing the key technologies of the future LISA mission, whose goal is the detection of gravitational waves through the measurement of the relative motion of dedicated proof masses.
In LISA Pathfinder, a critical task is the release of two Test Masses (TMs); each TM has to be injected into free fall by a dedicated Grabbing Positioning and Release Mechanism (GPRM). Despite the symmetrical design of the GPRM, during the release, as an effect of asymmetric impulses exchanged by the TM and the release tips of the GPRM, the TM can acquire a residual momentum. The release is successful if the residual momentum of the TM can be compensated by the force authority of the capacity control, which allows to centre the TM in its housing; as a consequence, a residual momentum of the TM higher than a maximum requirement can be critical for the mission.
In the nominal release configuration, which assumes a monodimensional dynamics of the mechanism along the axis of the release tips, the residual momentum can be produced by the asymmetry of pushing forces (due to relative time delays between the two tips) or by two unbalanced adhesive pulls on the two sides. In particular, the low repeatability of the adhesive pulls suggests their characterization through a dedicated on-ground experimental campaign.
The characterization of the adhesive pulls exchanged by the TM and the GPRM has been the focus of the on-ground experimental campaigns performed by the University of Trento since the early 2000s. The Transferred Momentum Measurement Facility (TMMF) has been developed: a mock-up of the TM release, which allows a high measurability of the adhesive pulls and guarantees the representativeness of the experiment, has been tested in order to estimate the properties of the adhesive force at the contact between the two bodies. The estimated parameters, applied to a model of the in-flight release, allowed to predict that the effect of the asymmetric adhesive pulls applied by the GPRM to the TM should not be critical for the residual momentum.
In this thesis we report the completion of the research on the effect of adhesion in the TM release of LISA Pathfinder, by means of additional on-ground experimental campaigns, and by comparing the predictions with the actual behaviour of the GPRM in the releases performed during the early stages of the LISA Pathfinder mission (2016).
Prior to the launch of the mission, the on-ground TMMF facility has been modified in 2015 in order to host a copy of the GPRM, thus increasing the representativeness of the experiment w.r.t. the nominal release. The on-ground test campaign, consisting in several release tests, allowed to obtain a new (conservative) estimation of the effect of adhesion in the TM release of LISA Pathfinder.
The estimation of the adhesive effect, which yielded first a conservative prediction, has been then improved by investigating in detail the release dynamics of the TMMF. Thanks to a vibration mode-based model of the TMMF, the effect of the adhesive pull on the measured dynamics has been estimated with its uncertainty, thus yielding a more precise prediction for the in-flight case.
The launch of the LISA Pathfinder mission occurred on December 3, 2015, and prior to the beginning of the scientific operations the two TMs have been injected into free fall. Due to the criticalities observed in the releases, an additional in-flight release test campaign has been planned during the end-of-life activities (June 2017), by alternating several times grab and release of each TM. The in-flight release campaign yielded a statistical distribution of the residual momentum of the TM at the release, which we analysed in detail in order to characterize the actual in-flight GPRM performance. In particular, we focused on the deviation of the predictions (based on the assumption of nominal release) w.r.t. the in-flight observations, by looking for the motivations of the residual momentum measured in the in-flight case.
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Zambotti, Andrea. "Ground Testing and In-Flight Performance of a Space Mechanism." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/242871.
Повний текст джерелаАнотація:
LISA Pathfinder is a mission designed for testing the key technologies of the future LISA mission, whose goal is the detection of gravitational waves through the measurement of the relative motion of dedicated proof masses.
In LISA Pathfinder, a critical task is the release of two Test Masses (TMs); each TM has to be injected into free fall by a dedicated Grabbing Positioning and Release Mechanism (GPRM). Despite the symmetrical design of the GPRM, during the release, as an effect of asymmetric impulses exchanged by the TM and the release tips of the GPRM, the TM can acquire a residual momentum. The release is successful if the residual momentum of the TM can be compensated by the force authority of the capacity control, which allows to centre the TM in its housing; as a consequence, a residual momentum of the TM higher than a maximum requirement can be critical for the mission.
In the nominal release configuration, which assumes a monodimensional dynamics of the mechanism along the axis of the release tips, the residual momentum can be produced by the asymmetry of pushing forces (due to relative time delays between the two tips) or by two unbalanced adhesive pulls on the two sides. In particular, the low repeatability of the adhesive pulls suggests their characterization through a dedicated on-ground experimental campaign.
The characterization of the adhesive pulls exchanged by the TM and the GPRM has been the focus of the on-ground experimental campaigns performed by the University of Trento since the early 2000s. The Transferred Momentum Measurement Facility (TMMF) has been developed: a mock-up of the TM release, which allows a high measurability of the adhesive pulls and guarantees the representativeness of the experiment, has been tested in order to estimate the properties of the adhesive force at the contact between the two bodies. The estimated parameters, applied to a model of the in-flight release, allowed to predict that the effect of the asymmetric adhesive pulls applied by the GPRM to the TM should not be critical for the residual momentum.
In this thesis we report the completion of the research on the effect of adhesion in the TM release of LISA Pathfinder, by means of additional on-ground experimental campaigns, and by comparing the predictions with the actual behaviour of the GPRM in the releases performed during the early stages of the LISA Pathfinder mission (2016).
Prior to the launch of the mission, the on-ground TMMF facility has been modified in 2015 in order to host a copy of the GPRM, thus increasing the representativeness of the experiment w.r.t. the nominal release. The on-ground test campaign, consisting in several release tests, allowed to obtain a new (conservative) estimation of the effect of adhesion in the TM release of LISA Pathfinder.
The estimation of the adhesive effect, which yielded first a conservative prediction, has been then improved by investigating in detail the release dynamics of the TMMF. Thanks to a vibration mode-based model of the TMMF, the effect of the adhesive pull on the measured dynamics has been estimated with its uncertainty, thus yielding a more precise prediction for the in-flight case.
The launch of the LISA Pathfinder mission occurred on December 3, 2015, and prior to the beginning of the scientific operations the two TMs have been injected into free fall. Due to the criticalities observed in the releases, an additional in-flight release test campaign has been planned during the end-of-life activities (June 2017), by alternating several times grab and release of each TM. The in-flight release campaign yielded a statistical distribution of the residual momentum of the TM at the release, which we analysed in detail in order to characterize the actual in-flight GPRM performance. In particular, we focused on the deviation of the predictions (based on the assumption of nominal release) w.r.t. the in-flight observations, by looking for the motivations of the residual momentum measured in the in-flight case.
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Vignotto, Davide. "Analysis of the in-Flight Performance of a Critical Space Mechanism." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/323575.
Повний текст джерелаАнотація:
Gravitational waves detection is a challenging scientific objective, faced by scientist in the last 100 years, when Einstein theorized their existence. Despite multiple attempts, it was only in 2016 that the first observation of a gravitational wave was officially announced. The observation, worth a Nobel Prize, was made possible thanks to a worldwide collaboration of three large ground-based detectors. When detecting gravitational waves from ground, the noisy environment limits the frequency bandwidth of the measurement. Thus, the type of cosmic events that are observable is also limited. For this reason, scientists are developing the first gravitational waves detector based in space, which is a much quieter environment, especially in the sub-Hertz bandwidth. The space-based detector is named laser interferometer space antenna (LISA) and its launch is planned for 2034. Due to the extreme complexity of the mission, involving several new technologies, a demonstrator of LISA was launched and operated between 2015 and 2017. The demonstrator mission, called LISA Pathfinder (LPF), had the objective to show the feasibility of the gravitational waves observation directly from space, by characterizing the noise affecting the relative acceleration of two free falling bodies in the milli-Hertz bandwidth. The mission was a success, proving the expected noise level is well below the minimum requirement.
The free-falling bodies of LPF, called test masses (TMs), were hosted inside dedicated electrode housings (EH), located approximately 30 cm apart inside the spacecraft. When free falling, each TM stays approximately in the center of the EH, thus having milli-meter wide gaps within the housing walls. Due to the presence of such large gaps, the TMs were mechanically constrained by dedicated mechanisms (named CVM and GPRM) in order to avoid damaging the payload during the launch phase and were released into free fall once the spacecraft was in orbit. Prior to the start of the science phase, the injection procedure of the TMs into free-fall was started. Such a procedure brought each TM from being mechanically constrained to a state where it was electro-statically controlled in the center of the EH. Surprisingly, the mechanical separation of the release mechanism from the TM caused unexpected residual velocities, which were not controllable by the electrostatic control force responsible for capturing the TM once released. Therefore, both the TMs collided with either the surrounding housing walls or the release mechanism end effectors. It was possible to start the science phase by manually controlling the release mechanism adopting non-nominal injection strategies, which should not be applicable in LISA, due to the larger time lag. So, since any release mechanism malfunctioning may preclude the initialization of LISA science phase, the GPRM was extensively tested at the end of LPF, by means of a dedicated campaign of releases, involving several modifications to the nominal injection procedure. The data of the extended campaign are analyzed in this work and the main conclusion is that no optimal automated release strategy is found for the GPRM flight model as-built configuration that works reliably for both the TMs producing a nominal injection procedure. The analysis of the in-flight data is difficult since the gravitational referencesensor of LPF is not designed for such type of analysis. In particular, the low sampling frequency (i.e., 10 Hz) constitutes a limiting factor when detecting instantaneous events such as collisions of the TM. Despite the difficulties of extracting useful information on the TM residual velocity from the in-flight data, it is found that the main cause of the uncontrollable state of the released TM is the collision of the TM with the plunger, i.e., one of the end-effectors of the GPRM. It is shown that the impact is caused by the oscillation of the plunger or by the elastic relaxation of the initial preload force that holds the TM. At the end of the analysis, some improvements to the design of the release mechanism are brie y discussed, aimed at maximizing the probability of performing a successful injection procedure for the six TMs that will be used as sensing bodies in the LISA experiment.
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Harris, Jemma M. "Testing a mechanism for the assessment of operators' cognitive skills in advanced technology environments." View thesis, 2009. http://handle.uws.edu.au:8081/1959.7/46219.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--University of Western Sydney, 2009.A thesis presented to the University of Western Sydney, College of Arts, School of Psychology, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographies.
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Harris, Jemma M. "Testing a mechanism for the assessment of operators' cognitive skills in advanced technology environments." Thesis, View thesis, 2009. http://handle.uws.edu.au:8081/1959.7/46219.
Повний текст джерелаАнотація:
Early childhood curriculum is limited when early multiliteracies are insufficiently understood. The purpose of this doctorate is to investigate and document children’s early multiliteracies. Children actively learn multiliteracies, including critical dialogue, through their relationships and interactions within family and community. My goal is to influence early childhood policy-makers and educators to reconceptualise early multiliteracies through examining family practices, children’s agency and critical dialogue, subsequently strengthening pedagogical practice. This reconceptualisation is crucial to ensure engaging curriculum and equitable multiliteracies learning opportunities for all children. The challenge lies in deepening the integration of these distinctive themes within a broad curriculum. Papers contained in this portfolio examine young children’s multiliteracies, at home and in educational settings from theoretical, practice and philosophical perspectives. They present findings from four research projects which respectively focus on early literacy and social justice, internet services, play and literacy, and critical dialogue. These projects primarily draw on qualitative strategies of inquiry located within the constructivist-interpretative paradigm. Three projects involved participants from largely metropolitan and coastal New South Wales in Australia, whilst one took a national perspective by engaging a small number of participants across Australia. My research strategies emerging from an educational ethnographic stance included grounded theory, case study and practitioner research. Methods of collecting and analysing evidence drew on literature, observations, individual and group interviews, focus groups and artifacts. The portfolio brings together the major themes of family practices, children’s agency and critical dialogue. My papers argue for educators and policy makers to reconceptualise early multiliteracies from children’s lived experiences, to strengthen relationships with families and so expand possibilities for all children’s multiliteracies learning and critical dialogue, especially enabling children to critique their social worlds. This portfolio comprises an Introduction, an Overarching Statement, a Record of Research Participation, Evidence of Scholarly Activity containing 11 portfolio papers and Appendices and References. The Overarching Statement outlines themes within this doctorate in relation to literature and examines the directions which shape the portfolio papers. Next this statement identifies and rationalises the four research projects and research events. The strategies of inquiry as well as methods of collecting and analysing evidence are then explained. Next, the contribution of the research projects towards my personal and professional development, and the field of scholarship are given. Finally my future directions are outlined.
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Johnston, Michael C. "Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1511915506999995.
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Gazda, Daniel Bryan. "Development of colorimetric solid Phase Extraction (C-SPE) for in-flight Monitoring of spacecraft Water Supplies." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835309-K3fMzj/webviewable/.
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(11014071), Vivek Muralidharan. "Stretching Directions in Cislunar Space: Stationkeeping and an application to Transfer Trajectory Design." Thesis, 2021.
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The orbits of interest for potential missions are stable or nearly stable to maintain long term presence for conducting scientific studies and to reduce the possibility of rapid departure. Near Rectilinear Halo Orbits (NRHOs) offer such stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L1 and L2 NRHOs are proposed as long horizon trajectories for cislunar exploration missions, including NASA's upcoming Gateway mission. These stable or nearly stable orbits do not possess well-distinguished unstable and stable manifold structures. As a consequence, existing tools for stationkeeping and transfer trajectory design that exploit such underlying manifold structures are not reliable for orbits that are linearly stable. The current investigation focuses on leveraging stretching direction as an alternative for visualizing the flow of perturbations in the neighborhood of a reference trajectory. The information supplemented by the stretching directions are utilized to investigate the impact of maneuvers for two contrasting applications; the stationkeeping problem, where the goal is to maintain a spacecraft near a reference trajectory for a long period of time, and the transfer trajectory design application, where rapid departure and/or insertion is of concern.
Particularly, for the stationkeeping problem, a spacecraft incurs continuous deviations due to unmodeled forces and orbit determination errors in the complex multi-body dynamical regime. The flow dynamics in the region, using stretching directions, are utilized to identify appropriate maneuver and target locations to support a long lasting presence for the spacecraft near the desired path. The investigation reflects the impact of various factors on maneuver cost and boundedness. For orbits that are particularly sensitive to epoch time and possess distinct characteristics in the higher-fidelity ephemeris model compared to their CR3BP counterpart, an additional feedback control is applied for appropriate phasing. The effect of constraining maneuvers in a particular direction is also investigated for the 9:2 synodic resonant southern L2 NRHO, the current baseline for the Gateway mission. The stationkeeping strategy is applied to a range of L1 and L2 NRHOs, and validated in the higher-fidelity ephemeris model.
For missions with potential human presence, a rapid transfer between orbits of interest is a priority. The magnitude of the state variations along the maximum stretching direction is expected to grow rapidly and, therefore, offers information to depart from the orbit. Similarly, the maximum stretching in reverse time, enables arrival with a minimal maneuver magnitude. The impact of maneuvers in such sensitive directions is investigated. Further, enabling transfer design options to connect between two stable orbits. The transfer design strategy developed in this investigation is not restricted to a particular orbit but applicable to a broad range of stable and nearly stable orbits in the cislunar space, including the Distant Retrograde Orbit (DROs) and the Low Lunar Orbits (LLO) that are considered for potential missions. Examples for transfers linking a southern and a northern NRHO, a southern NRHO to a planar DRO, and a southern NRHO to a planar LLO are demonstrated.
Книги з теми "Space mechanism in-flight testing"
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Bjarke, Lisa J. An in-flight technique for wind measurement in support of the space shuttle program. Edwards, Calif: Ames Research Center, 1989.
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J, Ehernberger L., and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. An in-flight technique for wind measurement in support of the space shuttle program. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1990.
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J, Ehernberger L., and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. An in-flight technique for wind measurement in support of the space shuttle program. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1990.
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G, VanDyk Steven, Lockheed Martin Missiles & Space (Firm), NASA Glenn Research Center, and Aerospace Mechanisms Symposium (35th : 2001 : Mountain View, Calif.), eds. The role of bearing and scan mechanism life testing in flight qualification of the MODIS instrument. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 2001.
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G, VanDyk Steven, Lockheed Martin Missiles & Space (Firm), NASA Glenn Research Center, and Aerospace Mechanisms Symposium (35th : 2001 : Mountain View, Calif.), eds. The role of bearing and scan mechanism life testing in flight qualification of the MODIS instrument. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 2001.
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Ryan, Robert S. Practices in adequate structural design. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Branch, 1989.
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Modeling flight: The role of dynamically scaled free-flight models in support of NASA's aerospace programs. Washington, D.C: NASA, 2010.
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Chambers, Joseph R. Modeling flight: The role of dynamically scaled free-flight models in support of NASA's aerospace programs. Washington, D.C: NASA, 2010.
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Chambers, Joseph R. Modeling flight: The role of dynamically scaled free-flight models in support of NASA's aerospace programs. Washington, D.C: NASA, 2010.
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United States. National Aeronautics and Space Administration., ed. Reduced gravity multibody dynamics testing: Final report submitted to .... George C. Marshall Space Flight Center ... under contract no. NAS8-391331, delivery order 020. Auburn University, AL: Dept. of Aerospace Engineering, College of Engineering, Engineering Experiment Station, 1993.
Знайти повний текст джерелаЧастини книг з теми "Space mechanism in-flight testing"
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Sills, Joel W., and Matthew S. Allen. "Historical Review of “Building Block Approach” in Validation for Human Space Flight." In Sensors and Instrumentation, Aircraft/Aerospace, Energy Harvesting & Dynamic Environments Testing, Volume 7, 1–20. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-12676-6_1.
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Anderson, J. D., G. S. Levy, and N. A. Renzetti. "Application of the Deep Space Network (DSN) to the Testing of General Relativity." In Relativity in Celestial Mechanics and Astrometry, 329–44. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4602-6_45.
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Becedas, Jonathan, Andrés Caparrós, Antonio Ramírez, Pablo Morillo, Esther Sarachaga, and Almudena Martín-Moreno. "Advanced Space Flight Mechanical Qualification Test of a 3D- Printed Satellite Structure Produced in Polyetherimide ULTEMTM." In Advanced Engineering Testing. InTech, 2018. http://dx.doi.org/10.5772/intechopen.79852.
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Nicolopoulou, Eleni P., Panagiotis K. Papastamatis, and Ioannis F. Gonos. "Electromagnetic Transients." In Recent Trends on Electromagnetic Environmental Effects for Aeronautics and Space Applications, 226–63. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4879-0.ch008.
Повний текст джерелаАнотація:
This chapter aims at presenting the current international standards and the recent bibliography regarding the transient phenomena associated with space systems, with emphasis on the EMC requirements. The first section of the chapter focuses on the description of the physical mechanisms causing transient electromagnetic phenomena in space. The second section reviews the procedures proposed for testing the immunity of space equipment against these transients, as described in the current space standards and in recent bibliography as non-standardized testing procedures. Finally, the last section investigates possible mitigation approaches and design guidelines against these electromagnetic disturbances, essential for every space system designer.
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Samuelson, Larissa K., John P. Spencer, and Gavin W. Jenkins. "A Dynamic Neural Field Model of Word Learning." In Theoretical and Computational Models of Word Learning, 1–27. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2973-8.ch001.
Повний текст джерелаАнотація:
Word learning is a complex phenomenon because it is tied to many different behaviors that are linked to multiple perceptual and cognitive systems. Further, recent research suggests that the course of word learning builds from effects at the level of individual referent selection or noun generalization decisions that accumulate on a moment-to-moment timescale and structure subsequent word learning behaviors. Thus, what is needed for any unified theory of word learning is 1) an account of how individual decisions are made across different contexts, including the details of how objects are encoded, represented, and selected in the course of a word learning behavior; and 2) a mechanism that builds on these individual, contextually specific decisions. Here, the authors present a Dynamic Neural Field (DNF) Model that captures processes at both the second-to-second and developmental timescales and provides a process-based account of how individual behaviors accumulate to create development. Simulations illustrate how the model captures multiple word learning behaviors such as comprehension, production, novel noun generalization (in yes/no or forced choice tasks), referent selection, and learning of hierarchical nominal categories. They also discuss how the model ties developments in these tasks to developments in object perception, working memory, and the representation and tracking of objects in space. Finally, the authors review empirical work testing novel predictions of the model regarding the roles of competition and selection in forced-choice and yes/no generalization tasks and the role of space in early name-object binding.
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Ekambaram, Vijay, Vivek Sharma, and Nitendra Rajput. "Mobile Application Testing." In Mobile Application Development, Usability, and Security, 25–53. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0945-5.ch002.
Повний текст джерелаАнотація:
Statistics hold that 80% of the mobile applications are deleted after just one-time use. A significant reason for this can be attributed to the quality of the mobile application, thus impressing on the need for testing a mobile application before it is made available on the app stores. At the same time, the mobile application lifecycle time is shrinking. So while operating systems used to get release about once in a couple of years, mobile operating systems get updated within months. And talking of apps, new apps are expected to be built and released in a matter of weeks. This impresses the need for automated mechanisms to do mobile testing. The space of mobile application testing is challenging owing to the variety of phone devices, the operating systems and the conditions under which an app can be used by the user in the wild. This chapter is focused on tools and techniques that are used for automated testing of mobile applications.
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"Leak testing of Chinese Space Laboratory hatch in a thermal vacuum environment." In Advances in Engineering Materials and Applied Mechanics, 97–102. CRC Press, 2015. http://dx.doi.org/10.1201/b19268-18.
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Galván, Lilia Carolina Rodríguez, and Carlos Morán Dosta. "A Conceptual Framework for Ethical Decision Making in Organizations." In Contemporary Issues Surrounding Ethical Research Methods and Practice, 212–33. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8562-8.ch009.
Повний текст джерелаАнотація:
This chapter addresses the lack of a framework that allows the generation of mechanisms and processes that benefit ethical decision making in organizations in order to promote civic virtue in its members. The authors explore how constructing spaces promote an honest and open dialogue among citizens, associations, business, and various levels of government. These spaces encourage the development of mechanisms and processes for social and personal benefit among its participants. The conceptual framework discussed is created by De la Cruz and Sasia (2013), named the Ethical Triangle Model. This model proposes at least three dimensions in an organization: legitimacy, motivation, and capacity. The proposed conceptual framework is dynamic and it is applicable to any organization. Future research must be made for testing the framework proposed here.
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Yelamarthi, Kumar, Raghudeep Kannavara, and Sanjay Boddhu. "A Perceptual Computing Based Gesture Controlled Quadcopter for Visual Tracking and Transportation." In Unmanned Aerial Vehicles, 131–41. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8365-3.ch005.
Повний текст джерелаАнотація:
One of the fundamental challenges faced by an inexperienced user in portable unmanned aerial vehicle (UAV) such as quadcopters is flight control, often leading to crashes. Addressing this challenge, and leveraging upon the technological advancement in perceptual computing and computer vision, this research presents a modular system that allows for hand gesture based flight control of UAV, alongside a transport mechanism for portable objects. In addition to ascertain smooth flight control by avoiding obstacles in navigation path, real-time video feedback is relayed from the UAV to user, thus allowing him/her to take appropriate actions. This paper presents the design implementation by discussing the various sub-systems involved, inter system communication, and field tests to ascertain operation. As presented from testing results, the proposed system provides efficient communication between the subsystems for smooth flight control, while allowing for safe transport of portable objects.
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Yang, Ziyu, Xiaokui Yue, and Chuang Liu. "Attitude Stabilization of Flexible Spacecraft Using Output Feedback Controller." In Advanced Control of Flight Vehicle Maneuver and Operation, 127–54. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815050028123040007.
Повний текст джерелаАнотація:
Spacecraft in space may have some certain non-cooperative characteristics due to the service life limit, fuel exhaustion, component fault, structural fatigue damage, or after performing certain space tasks such as capturing non-cooperative targets. In modeling, these non-cooperative characteristics are often manifested in uncertain and unknown inertia, model parameters uncertainty, actuator faults, etc. In this paper, aiming at the attitude stability control problem of such flexible spacecraft, the attitude dynamics modeling is completed by introducing the nominal inertia to construct the comprehensive disturbance term including external disturbance, inertia uncertainty and actuator failure. Then, a static output feedback (SOF) controller is applied to model the closed-loop attitude control system a stable negative imaginary (NI) system with H∞ performance constraints according to NI theory. As long as the optimization variables approach zero, the LMI-based iterative algorithm can find such the static output feedback controller to stabilize the flexible spacecraft. It is worth mentioning that an event-trigger mechanism is introduced into the control scheme to reduce communication pressure. Finally, the numerical simulation is carried out in the presence of controller gain perturbations and model parameter uncertainty. The results of the simulation demonstrate the effectiveness, robustness and non-fragility of the control method.<br>
Тези доповідей конференцій з теми "Space mechanism in-flight testing"
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BENTLEY, D., and D. TISDALE. "Development testing of TSS-1 Deployer tether control system mechanisms." In 3rd Tethers in Space/ Toward Flight International Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-1594.
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Gallois, Augustin, Karthik Mallabadi, Clément López, Eliott Marceau, Sérgio Silva, and Stéphanie Lizy-Destrez. "Lotus: Testing origami-inspired structures in microgravity." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.096.
Повний текст джерелаАнотація:
Many space technologies are enabled by deployable mechanisms or structures to function: solar panels, radiators, and even crewed stations and rovers subsystems need to be stowed and deployed to fit in a launcher fairing and avoid unwanted vibrations during launch. Among those structures, the deployment of large membranes and panels can be designed with the help of an unexpected technique: origami folding. The idea has been spreading in every field of engineering in the past few years; compact, rigid-folded structures that can change shape in one simple motion fascinate micro-robotics as well as aerospace engineers. Origami-inspired structures can be engineered to answer many needs. The available launch volume can be optimized, creases can improve the rigidity of a structure while keeping it lightweight, thickness can be accounted for, and complex surfaces can be approximated by flat-foldable mechanisms. Several major space actors, such as the National Aeronautics and
Space Administration (NASA) and the Japan Aerospace Exploration Agency (JAXA), have already implemented such techniques successfully or plan to do so in the near future. Following these breakthroughs, student project “Lotus” was submitted to the Parabole 2022 contest, an opportunity to test student projects in microgravity during a parabolic flight campaign organized by the French Space Agency and its subsidiary Novespace. The 5-members international student team will characterize and analyse the deployment and folding of innovative origami structure models for current and future space applications, especially volumes for deployable habitats, fuel tanks, or other resource containers such as asteroids and regolith; three stereo cameras will capture the geometry at different set speeds. To maximize the scientific return, several shapes and geometric parameters will be tested: three distinct structures are proposed to be tested, mostly limited by the volume available for the
experiment. The models tested will be as similar as possible to their full-size counterparts, being made of space-grade polyimide, and their dynamics will be assessed in near-0g conditions to have a deployment environment that is as accurate as possible. These results will be compared with on-ground experiments with a similar experimental setup.
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Zhang, Xinjie, and Changxiang Yan. "Application of precision harmonic gear drive in focusing mechanism of space camera." In 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies, edited by Xiangang Luo and Georg von Freymann. SPIE, 2010. http://dx.doi.org/10.1117/12.866749.
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Crazzolara, Blanca, Patrick Gowran, and Jordi Vàzquez Mas. "Fly A Rocket! Programme: assembly, testing and post-flight review of a sounding rocket payload." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.127.
Повний текст джерелаАнотація:
The Fly a Rocket! programme is a hands-on project offered by the European Space Agency’s Education Office in collaboration with Andøya Space Education and the Norwegian Space Agency (Norsk Romsenter). The programme, which comprises an online pre-course and a hands-on launch campaign, represents a unique opportunity for european university students from different backgrounds to build, test, and launch a sounding rocket and obtain practical experience. The pre-course strengthened the understanding of rocket science of the students, and taught them about topics such as the rocket dynamics, propulsion, and orbital mechanics in preparation for the campaign. The students were divided into three teams, each with different responsibilities: Sensors Experiments, Telemetry and Data Readout, and Payload. The paper will focus on the work done by the team responsible for the rocket payload. The Payload team was responsible for the sensor placement of the rocket. They ensured the readiness of all the sensors and key components of the rocket. In addition, they were an integral part of the countdown procedure, the arming of the rocket and the performance of the sensors. After the launch, the data was analysed and presented according to four previously defined scientific cases. A GPS and a barometer were used in order to obtain the rocket trajectory. Both methods showed similar results. The GPS detected an apogee of 8630.11 ±2.4m. With an optical sensor it was possible to detect clouds which were verified with a humidity sensor. Additionally, the spin rate of the rocket could be detected with the optical sensor and a magnetometer by doing a Fourier Analysis. The rocket reached a spin rate of about 19 Hz after approximately 10 s after the firing. The results of the spin rate correspond to the results obtained with an accelerometer.
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Jalba, C., P. Milev, P. Schulz, A. Pflug, P. Ramm, O. Gusland, I. Ghitiu, et al. "DEAR project: Lunar dust surface interactions, risk and removal investigations." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.019.
Повний текст джерелаАнотація:
The DEAR project (Dusty Environment Application Research) investigates the interaction between lunar regolith and surfaces and components relevant for lunar exploration. Based on the TUBS regolith simulant which is representative in chemistry, size and shape properties to Moon soils to study the regolith transport, adhesion and strategies for cleaning. The regolith simulant will be applied to thermal, structural, optical sensor, sealing and other astronautic systems, providing input for requirements, justification and verification. The key applications are split in human space flight regolith investigations, wrinkled surface with random movement and hardware surfaces, flat material defined movement. The paper provides an overview of the DEAR project including a discussion of the first results, in particular vibration, shock and micro-vibration on regolith bearing surfaces. The investigation shall enable better understand the regolith layers interaction and the release mechanism, as well as potential cross contamination and cleaning strategies. The research is complemented by simulation of the regolith motion as parameter surface plasma interactions. The project is funded and supported by the European Space Agency (ESA). DEAR specifically addresses the development and testing of lunar dust removal strategies on optics, mechanisms and human space flight hardware (e.g., space suits). As the Moons regolith is known to be highly abrasive, electrically chargeable, and potentially chemically reactive, lunar dust might reduce the performance of hardware, such as cameras, thermal control surfaces and solar cells. The dust can cause malfunction on seals for on/off mechanisms or space suits. Of particular interest are risk assessment, avoidance, and cleaning techniques such as the use of electric fields to remove lunar dust from surfaces. Representative dust (e.g., regolith analogues of interesting landing sites) will be used in a dedicated test setup to evaluate risks and effects of lunar dust. We describe designs and methods developed by the DEAR consortium to deal with the regolith-related issues, in particular an electrode design to deflect regolith particles, cleaning of astronautical systems with CO2, design of a robotic arm for the testing within the DEAR chamber, regolith removal via shock, and regolith interaction with cleanroom textiles
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Thompson, Joseph, David Murphy, Jack Reilly, Lána Salmon, Rachel Dunwoody, Maeve Doyle, Sarah Walsh, et al. "Thermal characterization testing of a robust and reliable thermal knife HDRM (Hold Down and Release Mechanism) for CubeSat deployables." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.079.
Повний текст джерелаАнотація:
Thermal knife HDRMs (Hold Down and Release Mechanisms) are commonly used in CubeSats and other small satellites. However, detailed information on proven designs is difficult to find. Design of a robust and reliable mechanism can present technical challenges which may only become apparent during testing, and often only when tested in a space representative environment. A custom thermal knife HDRM was designed and built for the antenna deployment module of EIRSAT-1 to deploy four coil spring antenna elements, but the same or a similar design could be repurposed quite easily to release a wide range of CubeSat deployables. In this design resistors are used to cut dyneema lines. For robustness and reliability, the thermal response of the mechanism must be well understood. To reach the melting point of the dyneema (150C) the power dissipated in the resistors must often exceed the maximum rated value. Therefore, choosing the operating current and the burn time is a careful trade-off between ensuring that the resistor reliably cuts the dyneema line and ensuring that the resistor, solder joints, PCB and nearby components are not damaged by the high temperatures. These choices are further complicated by the requirement that the mechanism operates over a range of temperatures. A thermal vacuum test campaign was carried out to better understand and characterise the thermal behaviour of the EIRSAT-1 mechanism. For the test a model of the mechanism was built with several temperature sensors installed. Two of these sensors were installed directly on the body of the resistors using a thermally conductive epoxy. Burn tests were performed in vacuum at temperatures between -37C and +56C. The test shows many interesting results including the effect of the dyneema lines on the thermal response, the possibility of desoldering the burn resistors and a comparison between the performance at ambient and vacuum conditions. Finally, a summary is given of the key technical challenges associated with this type of mechanism along with some recommendations to help make future designs more robust and reliable.
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Zhong, Peifeng, Chuang Li, Nan Jing, Yaqin Chong, and Guorui Ren. "Research on lightweight passive deployment mechanism for the secondary mirror in the deployable space telescope." In Eighth International Symposium on Advanced Optical Manufacturing and Testing Technology (AOMATT2016), edited by Xiangang Luo, Tianchun Ye, Tingwen Xin, Song Hu, Minghui Hong, and Min Gu. SPIE, 2016. http://dx.doi.org/10.1117/12.2243221.
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Canfield, Stephen L., Marshall A. Norris, Seth V. Knight, and Kirk F. Sorensen. "Dynamic Testing and Model Validation of a Capture Mechanism for Rendezvous Between a Space Tether and Payload." In ASME 2006 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/detc2006-99594.
Повний текст джерелаАнотація:
Momentum eXchange Electrodynamic Reboost, or MXER, tether systems have been proposed to serve as an “upper stage in space” [1]. A MXER tether station would boost spacecraft from low Earth orbit to a high-energy orbit quickly, like a high-thrust rocket. Then, using the same principles that make an electric motor work, it would slowly rebuild its orbital momentum by pushing against the Earth’s magnetic field without using any propellant. One of the significant challenges in developing a momentum-exchange / electrodynamic reboost tether system is in the analysis and design of the capture mechanism and its effects on the overall dynamics of the system [2]. A capture mechanism that provides nearly passive operation is presented and described in [3] and led to the fabrication of a prototype article of this mechanism. This paper will describe the process of testing this prototype in a dynamically similar environment and validating an associated dynamic model. The primary contributions of this paper will be a description of the proposed capture mechanism concept and associated testing process and the validation of a dynamic model of this mechanism.
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García Mozos, Luis, Devonjit Saroya, Yannick Roelvink, Naël dos Santos D'Amore, Stefano Gabetti, Jorge Galván Lobo, Catarina Lobo, et al. "Artery in Microgravity (AIM): Assembly, integration, and testing for a student payload for the ISS." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.097.
Повний текст джерелаАнотація:
The Artery in Microgravity (AIM) project was the first experiment to be selected for the “Orbit Your Thesis!” programme of the European Space Agency Academy. It is a 2U cube experiment that will be operated in the International Commercial Experiment (ICE) Cubes facility onboard the International Space Station. The experiment is expected to be launched on SpaceX-25 in mid-2022. The project is being developed by an international group of students from ISAE-SUPAERO and Politecnico di Torino. The objective of the experiment is to study haemodynamics in the space environment applied to coronary heart disease. The outcomes of this testbench will contribute to understanding the effects of radiation and microgravity on the circulatory system of an astronaut, specifically the behaviour in long-term human spaceflight. It will also help to ascertain the feasibility of individuals suffering from this kind of disease going to space someday. The cornerstones of the experiment are two models of 3D-printed artificial arteries, in stenotic and stented conditions respectively. Blood-mimicking fluid composed of water and glycerol is circulated
through the arteries in a closed hydraulic loop, and a red dye is injected for flow visualisation. Drops of pressure and image analysis of the flow will be studied with the corresponding sensors and camera. The pH of the fluid will also be monitored to assess the effect of augmented radiation levels on the release of particles from the metallic stent. Some delays were experienced in the project due to the COVID-19 pandemic and to implement design improvements. Improvements were made to several aspects of the design including mechanics (e.g. remanufacturing the reservoir with surface treatment against corrosion, leak prevention measures), software (e.g. upgrading to Odroid-C4 and migrating the code to
Python), and electronics (e.g. several iterations of the interface PCB design). This iterative process of identifying areas of concern and designing and implementing solutions has resulted in many lessons learned. The paper will outline in detail Phase D – Qualification and Production of the AIM experiment cube, with special insight on the implementation of the improvements. Previously, at the Symposium on Space Educational Activities in 2019 in Leicester, the initial phases of the design and development of the cube were presented. This year, the final flight model and the results of validation testing before launching on SpaceX-25 are presented. Lessons learned throughout the course of the project are also highlighted for students embarking on their own space-related educational activities.
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Seckar, Chris, Larry Guy, Angela DiFronzo, and Carl Weimer. "Performance testing of an Active Boresight Mechanism for use in the CALIPSO space bourne LIDAR mission." In Optics & Photonics 2005, edited by Alson E. Hatheway. SPIE, 2005. http://dx.doi.org/10.1117/12.614516.
Повний текст джерелаЗвіти організацій з теми "Space mechanism in-flight testing"
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Clausen, Jay, D. Moore, L. Cain, and K. Malinowski. VI preferential pathways : rule or exception. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41305.
Повний текст джерелаАнотація:
Trichloroethylene (TCE) releases from leaks and spills next to a large government building occurred over several decades with the most recent event occurring 20 years ago. In response to a perceived conventional vapor intrusion (VI) issue a sub-slab depressurization system (SSDS) was installed 6 years ago. The SSDS is operating within design limits and has achieved building TCE vapor concentration reductions. However, subsequent periodic TCE vapor spikes based on daily HAPSITE™ measurements indicate additional source(s). Two rounds of smoke tests conducted in 2017 and 2018 involved introduction of smoke into a sanitary sewer and storm drain manholes located on effluent lines coming from the building until smoke was observed exiting system vents on the roof. Smoke testing revealed many leaks in both the storm sewer and sanitary sewer systems within the building. Sleuthing of the VI source term using a portable HAPSITE™ indicate elevated vapor TCE levels correspond with observed smoke emanation from utility lines. In some instances, smoke odors were perceived but no leak or suspect pipe was identified suggesting the odor originates from an unidentified pipe located behind or enclosed in a wall. Sleuthing activities also found building roof materials explain some of the elevated TCE levels on the 2nd floor. A relationship was found between TCE concentrations in the roof truss area, plenum space above 2nd floor offices, and breathing zone of 2nd floor offices. Installation of an external blower in the roof truss space has greatly reduced TCE levels in the plenum and office spaces. Preferential VI pathways and unexpected source terms may be overlooked mechanisms as compared to conventional VI.
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Clausen, Jay, D. Moore, K. Miller, and L. Haines-Ecklund. VI preferential pathways of a large government building. Engineer Research and Development Center (U.S.), February 2022. http://dx.doi.org/10.21079/11681/43260.
Повний текст джерелаАнотація:
Trichloroethylene (TCE) releases from leaks and spills next to a large government building occurred over several decades with the most recent event occurring 20 years ago. In response to a perceived conventional vapor intrusion (VI) issue a sub-slab depressurization system (SSDS) was installed 6 years ago. The SSDS is operating within design limits and has achieved building TCE vapor concentration reductions. However, subsequent periodic TCE vapor spikes based on daily HAPSITE™ measurements indicate additional source(s). Two rounds of smoke tests conducted in 2017 and 2018 involved introduction of smoke into a sanitary sewer and storm drain manholes located on effluent lines coming from the building until smoke was observed exiting system vents on the roof. Smoke testing revealed many leaks in both the storm sewer and sanitary sewer systems within the building. Sleuthing of the VI source term using a portable HAPSITE™ indicate elevated vapor TCE levels correspond with observed smoke emanation from utility lines. Sleuthing activities also found building roof materials explain some of the elevated TCE levels on the 2nd floor. Installation of an external blower in the roof truss space has greatly reduced TCE levels. Preferential VI pathways and unexpected source terms may be overlooked mechanisms as compared to conventional VI.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland, and Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, May 1995. http://dx.doi.org/10.32747/1995.7613013.bard.
Повний текст джерелаАнотація:
The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Повний текст джерелаАнотація:
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.