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On-orbit assembly strategies are proposed for an orb-shaped solar array which forms the main structure of a space solar power station. A dynamic model for the structural vibration under the influence of the gravity gradient is proposed by combining the Tschauner-Hempel equation and a finite element model of an elastic beam. The motion of the robot, used for on-orbit assembly, is described analogously to a classical vehicle-bridge coupled dynamic model. Assembly strategies are presented and analyzed, consisting of a single-robot assembly strategy, an assembly strategy using two robots and structural reinforcements. The proposed methods are verified in simulation and tuned to minimize the structural vibration during assembly. 1. A dynamic analysis algorithm is proposed to analyze the vibration of space structure. 2. Several practical engineering factors are considered during installation. 3. Comparison of two robot installation schemes considering multiple factors. [ABSTRACT FROM AUTHOR]

Abstract Electrical energy production using renewable energies is one of the most important challenges in recent years. Among renewable energies, it is worth highlighting photovoltaic and thermoelectric systems due to their adaptation to the Canary Islands. One of the most important issues to ensure the stability for solar power systems, mostly in insular grids as Canary Islands, is the precise knowledge of solar radiation. In this paper, we focus in Gridded Satellite data suitability for modelling Global Horizontal Irradiation (GHI) in islands with complicated orography, as Canary Islands. Solar radiation data retrieved from CM SAF and McClear model were analysed and compared with 22 ground measurement stations in Canary Islands. Moreover, this analysis presents the results of including a site-adaptation methodology for improving satellite suitability. We used different procedures to perform this site adaptation depending on the solar radiation conditions (clear sky or cloudy sky hours), the location of the measurement station (we establish two clusters according to the climate conditions) and the season. This study could provide information about satellite models suitability in islands and a better knowledge of solar radiation behavior. Furthermore, accurate satellite radiation data for wide spatial and temporal coverage could improve solar radiation modelling and forecasting. Highlights • Assessment of CM SAF satellite derived solar radiation data and clear sky models in islands. • Selection of clear sky hours and clustering of the region to obtain optimal site adaptation. • Discussion of satellite assessment and proposal a site-adaptation. [ABSTRACT FROM AUTHOR]

Abstract For the design of space structures, the dynamic coupling between equipment and the satellite (or between a satellite and the launcher) is usually avoided due to negative effects like high stresses produced by structural resonance. The usual procedure to assure the dynamic decoupling is by limiting the minimum value of natural frequency of the secondary structure to a value high enough above the main natural frequencies of the main structure. However, in some spacecraft configurations, it is unavoidable that some parts or equipment present natural frequencies close to the main natural frequencies of the spacecraft because these parts may be massive or may have a special interface design with low stiffness. This dynamic coupling provokes modifications on the modal behavior of the satellite, which can lead to a significant decrease in the first natural frequency of the entire satellite. To analyze this phenomenon, a representative but simple mathematical model is studied to evaluate the influence of the design parameters of space structures. Analytical expressions are obtained that can help to highlight the influence of the parameters. The results are demonstrated with the example of the UPMSat-2 satellite design. [ABSTRACT FROM AUTHOR]

The article discusses the proposals of Aden B. Meinel, a director of the Optical Sciences Center, University of Arizona, on a solar power generating system that will produce 1000 megawatts of electricity through thermal conversion of solar energy. Aden Meinel together with his wife, Marjorie Pettit Meinel, suggests that conversion can be done by the optical concentration of sunshine in ground collectors spread over desert region. Base on their study, this 1000 megawatt generating system require a solar power farm that cover an area of 3.8 kilometers on a side, for the collection of enough solar energy. They added, that the excess power from the generating system are useful to chemical and industrial processors.

In this research paper, a newly energy system consisting of parabolic trough solar collectors (PTSC) field, a thermoelectric generator (TEG), a Rankine cycle and a proton exchange membrane (PEM) is proposed. The integration is performed by establishing a TEG instead of the condenser as power generation and cooling unit thereafter surplus power output of the TEG is transferred to the PEM electrolyzer for hydrogen production. The integrated renewable energy system is comprehensively modeled and influence of the effective parameters is investigated on exergy and economic indicators through the parametric study to better understand the system performance. Engineering equation solver (EES) as a potential engineering tool is used to simulate the system and obtain the desired results. In order to optimize the system, a developed multi-objective genetic algorithm MATLAB code is applied to determine the optimum operating conditions of the system. Obtained results demonstrate that at optimum working condition from exergy viewpoint, exergy efficiency and total cost are 12.76% and 61.69 $/GJ, respectively. Multi-objective optimization results further show that the final optimal point which is well-balanced between exergy efficiency and total cost, has the maximum exergy efficiency of 13.29% and total cost of 63.96 $/GJ, respectively. The corresponding values for exergy efficiency and total cost are 10.01% and 60.21 $/GJ for optimum working condition from economic standpoint. Furthermore, hydrogen production at well-balanced operating condition would be 2.28 kg/h. Eventually, the results indicate that establishing the TEG unit instead of the condenser is a promising method to optimize the performance of the system and reduce total cost. [ABSTRACT FROM AUTHOR]

We present here an investigation of the arcing voltage threshold for GPS-like arrays performed in the Spacecraft Charging and Instrument Calibration Laboratory at the Air Force Research Laboratory’s Battlespace Environment Laboratory at Kirtland Air Force Base, New Mexico, USA. Our simulations were done under GPS-like plasma environments in a vacuum-plasma chamber. The arc voltage threshold found is compared with that predicted from the Los Alamos National Laboratory (LANL), detectors, and the question of to what degree were the indium tin oxide-coated cells on GPS properly grounded is discussed. It is shown through the current–voltage testing of the arrays pre- and postarcing that the anomalous power degradation seen on GPS satellites on orbit can be completely accounted for by arcing at the anomalous event rates seen by LANL radio frequency detectors onboard. Implications for arcing and contamination mitigation on future GPS satellites are presented. [ABSTRACT FROM PUBLISHER]

This study evaluates the large-scale seasonal phenology and physiology of vegetation over northern high latitude forests (40°–55°N) during spring and fall by using remote sensing of solar-induced chlorophyll fluorescence (SIF), normalized difference vegetation index (NDVI) and observation-based estimate of gross primary productivity (GPP) from 2009 to 2011. Based on GPP phenology estimation in GPP, the growing season determined by SIF time-series is shorter in length than the growing season length determined solely using NDVI. This is mainly due to the extended period of high NDVI values, as compared to SIF, by about 46 days (± 11 days), indicating a large-scale seasonal decoupling of physiological activity and changes in greenness in the fall. In addition to phenological timing, mean seasonal NDVI and SIF have different responses to temperature changes throughout the growing season. We observed that both NDVI and SIF linearly increased with temperature increases throughout the spring. However, in the fall, although NDVI linearly responded to temperature increases, SIF and GPP did not linearly increase with temperature increases, implying a seasonal hysteresis of SIF and GPP in response to temperature changes across boreal ecosystems throughout their growing season. Seasonal hysteresis of vegetation at large-scales is consistent with the known phenomena that light limits boreal forest ecosystem productivity in the fall. Our results suggest that continuing measurements from satellite remote sensing of both SIF and NDVI can help to understand the differences between, and information carried by, seasonal variations vegetation structure and greenness and physiology at large-scales across the critical boreal regions. [ABSTRACT FROM AUTHOR]

A satellite power system requires solar panels to provide energy and orientation. There are two regions in the orbital path of the satellite: the dark and bright region. The energy is provided by solar panels in the bright region and by flywheel energy storage system (FESS) in the dark region. Brushless DC (BLDC) motors are widely used in the FESS due to their low weight, high power density, high efficiency, high reliability, and high speed. Some mechanical resonances may occur due to physical features of the mechanical parts. Therefore, the current of the BLDC is dramatically increased because of the mechanical resonance. In this work, a current reference method was used to protect the power systems of the satellite from the current spikes of the solar power system. The parameters of the PI controller were calculated by using genetic algorithms. A FESS was designed and experimentally performed for high speed operation at about 20 krpm in the vacuumed environment. [ABSTRACT FROM AUTHOR]

To investigate the soiling behavior of solar energy systems like photovoltaics or concentrated solar power, glass samples were exposed to outdoor conditions in Doha, Qatar for one month. Soil formation on the glass was characterized at microstructural level using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further, elemental analysis of the crust was done with energy-dispersive X-ray spectroscopy (EDX). Small fibrous structures were found on the glass surface and dust particles, providing evidence of a cementation process leading to a strong adhesion of airborne dust particles. In contrast to the common perception, that cementation occurs via the precipitation of salt (sodium chloride) these needle structures were found to be mainly composed of oxides of Si, Mg and Al. This indicates that cementation processes in desert regions are enhanced by the growth of fibrous clay minerals. [ABSTRACT FROM AUTHOR]

Shape memory polymers (SMP) have the potential to be utilized as a lightweight, solid state actuator in modern reconfigurable structures including as a deployment system for satellite solar panels or morphing aircraft wings. This paper is primarily concerned with the use of Veriflex-S® shape memory polymer and bi-directional carbon-fiber-reinforced-polymer (CFRP) in a flexural unimorph actuator configuration. One of the major deficiencies of SMP unimorphs is the permanent set (unrecovered shape) after a single or multiple temperature cycle(s). The novel concept of incorporating transverse curvature in the CFRP substrate, similar to that of an extendable tape measurer, is proposed to improve the shape recovery by increasing the bending stiffness of the unimorph actuator to compensate for the lack of recovery of the SMP. A set of experiments was designed to investigate the influence of transverse curvature, the relative widths of SMP and CFRP substrates, and shape memory polymer thickness on actuator recoverability after multiple thermo-mechanical cycles. The performance of SMP unimorph actuators with varying degrees of transverse curvature were evaluated versus that of traditional SMP unimorphs incorporating a flat substrate. Digital image correlation was implemented to quantify the out-of-plane deflection of the unimorph composite actuators (UCAs) during the actuation cycle. Experimental results indicate that an actuator with transverse curvature significantly reduces the residual deformation by at least two orders of magnitude which could be further tailored to enhance the performance of shape memory polymers in reconfigurable arrangements. [ABSTRACT FROM AUTHOR]

Risk of arcing in space plasma environment on satellite solar panel has always been an issue of major concern in the aerospace community. The outcome of round robin tests performed in various laboratories has resulted in finalization of the guidelines for the ground test of satellite solar panel coupons (SSPCs). This is documented as ISO-11221 standards. Authenticity of arc plasma flashover (FO) parameters are still under debate. Some experimental findings that support the perimeter theory of arc FO on geostationary (GEO) satellites are discussed in this paper. It has been observed that characteristics of an the arc are dependent on its location on the solar coupon, bias charge (charge due to bias voltage and external capacitance), and the total charge dissipated during the arc discharge. It is also observed that the duration between the two consecutive arcs is directly proportional to the dissipated charge or energy of the latter arc. A combined dielectric consisting of solar cell, adhesive, Kapton, and Carbon Fiber Reinforced Polymer sheet holds charge during irradiation by the electron gun. This resembles surface FO capacitance. Arc energy is governed by the combined effects of a surface flashover capacitor (C-sf) and an external capacitor. It is observed that if intermittent arc duration is sufficiently longer than the gradual accumulation of charge on the SSPC, body may lead to a major arc. This would increase the probability of secondary arcs when the sustained arc environment is experienced by the satellite. To understand primary arcs on dielectrics, an artificial triple junction is prepared and exposed under adverse GEO-like space conditions. Various signatures identified from the arc current and arc neutralization current waveforms specify the behavior of these arcs at different locations on the coupon surface. In this paper, current waveforms of arcs captured on different types of solar panel coupons and their significance are studied. Information about arc energy, arc velocity, and neutralization velocity are extracted from the measured waveforms. [ABSTRACT FROM PUBLISHER]

Robotic systems are expected to play an increasingly important role in future space activities, such as repairing, upgrading, refuelling, and re-orbiting spacecraft. These technologies could potentially extend the life of satellites, enhance the capability of space systems, reduce the operation costs, and clean up the increasing space debris. Recent proposals for missions involving the use of space manipulators and/or automated transfer vehicles are presented as a solution for a lot of problems, which now affect the procedures and the performance of the in-orbit space systems. Other projects involving space manipulators have been developed by DARPA aiming to demonstrate several satellite servicing operations and technologies including rendez-vous, proximity operations and station-keeping, capture, docking, fluid transfer (specifically, “hydrazine”), and Orbit Replaceable Unit (ORU) transfer. Of course the dynamic coupling between the manipulator and its base mounting flexible solar arrays is very difficult to model. Furthermore, the motion planning of space robots is usually much more complicated than the motion planning of fixed-base manipulators. In this paper first of all the authors present a mixed NE/EL formulation suitable for synthesizing optimal control strategies during the deploying manoeuvres of robotic arms mounted on flexible orbiting platform (i.e. the chaser). Then two new control strategies able to compensate the flexibility excitations of the chaser satellite solar panels during the capturing of a flexible target spacecraft with the use of two robotic arms are presented and applied to a grasping manoeuvre. The mission is here divided into three main phases: the approaching, the docking and the post-grasping phase. Several numerical examples will complete the work. [ABSTRACT FROM AUTHOR]

Designs for geostationary solar power satellites are extremely large in scale, more than an order of magnitude larger than the International Space Station. A detailed study of solar power satellites' orbit dynamics is performed, obtaining a comprehensive understanding of the effect of perturbations on orbits of large solar power satellite structures over a time frame commensurate with proposed solar power satellites' lifetimes (30-40 years). Analytical equations derived by the process of averaging of the solar power satellites' equations of motion are used to determine the long-term orbital behavior. Previous solar power satellite studies have simply assumed geostationary Earth orbit, then designed control systems for maintaining it thus. It is found that an alternative solar power satellite orbital location, known as the geosynchronous Laplace plane, is superior to geostationary in many aspects. A solar power satellite in the geosynchronous Laplace plane requires virtually no fuel to maintain its orbit, minimizes the risk of debris creation at geosynchronous altitude, and is extremely operationally robust (i.e., loss of control is inconsequential). The geosynchronous Laplace plane solar power satellite saves on order of 105 kg per year in fuel compared with a geostationary solar power satellite for near-equivalent power delivery. It is also found that the microwave beam orbit perturbation, which is unique to the solar power satellites, contributes toward stabilization of the longitude of the solar power satellites. [ABSTRACT FROM AUTHOR]

In this work, the 55Mn spin-echo nuclear magnetic resonance technique is used to systematically analyze the complete substitutional series Co2Mn1-xFexSi in terms of the resonance frequencies of the satellite structure and the corresponding hyperfine fields of the 55Mn nuclei. The frequency spacing between satellite lines is constant within a compound, but decreases with increasing Fe concentration x, which originates in changes in the band structure. These changes are also responsible for the altered resonance frequencies observed for the same third shell environment but corresponding to a different overall Fe concentration x. All modifications in the hyperfine field upon substitution of Mn by Fe can be uniquely assigned to an entirely random distribution of Mn and Fe limited to only one (4b) out of four fcc sublattices constituting the L21 Heusler structure, demonstrating that the complete substitutional series Co2Mn1-xFexSi is crystallographically very well defined. This very high degree of order sets the stage for the observation of stable half-metallic ferromagnetism which is typically very sensitive to the structural order. [ABSTRACT FROM AUTHOR]

This paper begins with an introduction to the concept of space solar power (SSP) and summarizes selected prior studies of proposed solar power satellite (SPS) systems. The functional components of a generic SPS are delineated, and various approaches and promising concepts from prior and current development efforts are elucidated. The fundamentals of wireless power transfer for the SPS application are reviewed, including a discussion of retrodirective beam control approaches. A survey of related technology research and development campaigns for energy conversion and transmission modules for recently proposed modular architectures is outlined. Advances in solid state amplifier technology with relevance to SSP are reviewed, with areas of particular criticality highlighted. Performance metrics for proposed SPS systems and their components are enumerated, and efforts to design, fabricate, and test a prototype conversion module operating at 2.45 GHz in a space-like environment are described. [ABSTRACT FROM PUBLISHER]

Abstract: As a solution to the most critical problems with Solar power Satellite (SPS) development, a system is proposed which uses laser power transmission in space to a receiver high in the atmosphere that relays the power to Earth by either cable or microwave power transmission. It has been shown in the past that such hybrid systems have the advantages of a reduction in the mass of equipment required in geostationary orbit and avoidance of radio frequency interference with other satellites and terrestrial communications systems. The advantage over a purely laser power beam SPS is that atmospheric absorption is avoided and outages due to clouds and precipitation will not occur, allowing for deployment in the equatorial zone and guaranteeing year round operation. This proposal is supported by brief literature surveys and theoretical calculations to estimate crucial parameters in this paper. In relation to this concept, we build on a recently proposed method to collect solar energy by a tethered balloon at high altitude because it enables a low-cost start for bringing the first Watt of power to Earth giving some quick return on investment, which is desperately missing in the traditional SPS concept. To tackle the significant problem of GW-class SPSs of high launch cost per kg mass brought to space, this paper introduces a concept which aims to achieve a superior power over mass ratio compared to traditional satellite designs by the use of thin-film solar cells combined with optical fibres for power delivery. To minimise the aperture sizes and cost of the transmitting and receiving components of the satellite and high altitude receiver, closed-loop laser beam pointing and target tracking is crucial for pointing a laser beam onto a target area that is of similar size to the beam''s diameter. A recently developed technique based on optical phase conjugation is introduced and its applicability for maintaining power transmission between the satellite and high altitude receiver is assessed. It was found that the design of the high altitude receiver and the means of transporting the received power through the lower 21km of the atmosphere are inextricably linked. It was concluded that an initial small scale low-cost demonstration flight of the receiver that delivers power using existing technology could be undertaken in the near future. [Copyright &y& Elsevier]

Abstract: NOAA (National Oceanic and Atmospheric Administration) satellite series is known to suffer from what is known as the orbital drift effect. The Long Term Data Record (LTDR [Pedelty et al., 2007]), which provides AVHRR (Advanced Very High Resolution Radiometer) data from these satellites for the 80s and the 90s, is also affected by this orbital drift. To correct this effect on Land Surface Temperature (LST) time series, a novel method is presented here, which consists in adjusting retrieved LST time series on the basis of statistical information extracted from the time series themselves. This method is as simple and straightforward as possible, in order to be implemented easily for such a large dataset as the LTDR. The correction is applied on a pixel by pixel basis, and relies on a 2nd order polynomial fit of per satellite solar zenithal angle (SZA) anomalies against time. If the pixel time series is identified as contaminated by the orbital drift for any of the different satellite active periods, LST anomalies are fitted linearly against both time and the 2nd order polynomial fit of SZA anomalies. This double fit allows for the removal of orbital drift influence without removing eventual trends in the signal, which is of utmost importance for vegetation change detection. When applied to simulated LST time series, this method shows errors comparable to the errors associated to LST estimation for most cases. When applied to LTDR LST time series, the approach normalizes the distribution of LST values at the beginning and end of each satellite activity period, and visual inspection of the time series does not show any residual orbital drift in the corrected LST time series. The approach also improves the significance of retrieved trends through the whole time span of the LTDR dataset. The application of this method to the whole LTDR dataset could lead to the compilation of the first coherent global dataset of land surface temperature. [Copyright &y& Elsevier]

The article discusses the concept of space-based solar power (SBSP), highlighting an issue regarding the potential role of SBSP in the U.S. grand strategy for space. SBSP is a concept for upgrading energy system by placing large orbital power plants into orbit to collect the sun's raw energy and beam it down to where it is needed on the earth. It discusses the scope and feasibility for solar-power satellites.

Abstract: With the declining costs of flat plate and concentrating photovoltaic (PV) systems, solar PV generation in many sunny regions in Brazil will eventually become cost competitive with conventional and centralized power generation. Detailed knowledge of the local solar radiation resource becomes critical in assisting on the choice of the technology most suited for large-scale solar electricity generation. When assessing the energy generation potential of non-concentrating, fixed flat plate versus concentrating PV, sites with high levels of direct normal irradiation (DNI) can result in cost-competitive electricity generation with the use of high concentrating photovoltaic systems (HCPV). In large countries, where the transmission and distribution infrastructure costs and associated losses typical of centralized generation must be taken into account, the distributed nature of solar radiation should be perceived as a valuable asset. In this work we assess the potential of HCPV energy generation using satellite-derived DNI data for Brazil, a large and sunny country with a continental surface of 8.5millionkm2. The methodology used in the study involved the analysis of global horizontal, latitude-tilt, and direct normal solar irradiation data resulting from the Solar and Wind Energy Resource Assessment (SWERA) Project, and an estimate of the resulting electricity production potential, based on a review of HCPV generators operating at other sites. The satellite-derived solar irradiation data, with 10km×10km spatial resolution, were analysed over the whole country, in order to identify the regions where HCPV might present a considerable advantage over fixed plate PV on an annual energy generation basis. Our results show that there is a considerable fraction of the national territory where the direct normal solar irradiation resource is up to 20% higher than the latitude-tilt irradiation availability. Furthermore, these sites are located in the most industrially-developed region of the country, and indicate that with the declining costs of this technology, distributed multi-megawatt HCPV can be a good choice of technology for solar energy generation at these sites in the near future. [Copyright &y& Elsevier]

Abstract: The analysis of satellite solar power station (SSPS) is carried out for some specified locations (Delhi, Mumbai, Kolkata and Bengaluru) in India and consequently the performance of the system is evaluated for geostationary earth orbit (GEO) based SSPS, low earth orbit (LEO) based SSPS and Molniya (quasi geostationary) orbit based SSPS for sites located at different latitudes. The analysis of power; received energy over a year and weight of the rectenna array for the same beam intensity showed varied results for Molniya orbit based SSPS, LEO based SSPS and GEO based SSPS. The power delivered by the LEO SSPS was highest which indicated that this SSPS may be efficient for the short term power requirement. However, it is observed from the results of the energy received over a year that the GEO based system is suitable for base load power plant as it is capable of delivering constant energy through out a year. Further, the weight of the rectenna and hence the space required for ground station for same power output is smallest for Molniya orbit based system for a range of rectenna array radius considered. It is thus envisaged that the Molniya orbit based system would be a better choice for commercial use of SSPS. These findings may help for judicious selection of satellite orbit and ground station location for placing the satellite for SSPS for various applications. [Copyright &y& Elsevier]

The concept of beaming power to Earth from orbiting satellites dates back to the 1960s. In 1968, aerospace engineer Peter Glaser proposed collecting power from a 'mile-wide' solar array in geostationary orbit and beaming it down to Earth using microwaves. Space technology was now sufficiently mature to build a satellite capable of delivering 10-20kW of usable power within a five-year timeframe. [ABSTRACT FROM AUTHOR]

Two precursor satellites for the European satellite navigation system, Galileo have been launched, GIOVE-A and -B. Both spacecraft carry monitors to characterise the radiation environment in the MEO environment. CEDEX, built by the University of Surrey and Merlin, built by QinetiQ, are carried on GIOVE-A and SREM built by Oerlikon Space is on board GIOVE-B. All three monitors have been operating since their respective launches and have measured the trapped electron population as well as solar protons and GCRs. An electron energy spectrum has been derived from Merlin measurements and validated with data from GIOVE-B/SREM and the IREM instrument on the INTEGRAL observatory. The derived energy spectra are compared to environment models, suggesting a harder energy spectrum than expected, but not exceeding worst-case FLUMIC predictions. [ABSTRACT FROM AUTHOR]

The analysis of satellite solar power station (SSPS) is carried out for some specified locations in India and consequently the performance of the system is evaluated for geostationary earth orbit (GEO)-based SSPS and low earth orbit (LEO)-based SSPS for sites located at different latitudes. The analysis of power, the received energy over a year, and the received energy during a day for the same beam intensity show better results for LEO-based SSPS system as compared to GEO-based system. However GEO-based system is advantageous in the sense that it will deliver constant energy to the load throughout a year. Thus it is concluded that GEO-based system is suitable for base load power plant. The weight of the rectenna and hence the space required for ground station for same power output for GEO-based system is greater than that for LEO-based system which will in turn increase the overall cost of the GEO-based system. These findings may help for judicious selection of orbit for placing the satellite for SSPS. [ABSTRACT FROM AUTHOR]

This paper presents a methodology that is developed to assess the parasitic electromagnetic (EM) emissions of a satellite solar panel from a quasi-static to several tens of megahertz bandwidth. In the method, the solar panel is first modeled as an equivalent electric circuit, which allows the computation of the current distribution in all the elements using Spice-like software. The model is then converted into a network of electric dipoles, which permits to calculate the total EM emissions of the solar panel at a given point by the vectorial summation of the EM emissions due to each electric dipole. Thus, only the dipolar moment and the position and the orientation of each electric dipole are required. Encouraging experimental validations performed on a prototype solar panel are presented to illustrate the efficiency and the accuracy of the method. The method described in this paper is considered as a first step required in order to prepare wider applications on real satellites in the near future. [ABSTRACT FROM AUTHOR]

Abstract: Huge antennas has many useful applications in space as well as on the ground, for example, Solar Power Satellite to provide electricity to the ground, telecommunication for cellular phones, radars for remote sensing, navigation and observation, and so on. The S-310-36 sounding rocket was successfully launched on 22 January 2006 to verify our newly proposed scheme to construct huge antennas under microgravity condition in space. The rocket experiment has three main objectives, the first objective of which is to verify the Furoshiki deployment system [S. Nakasuka, R. Funase, K. Nakada, N. Kaya, J. Mankins, Large membrane “FUROSHIKI Satellite” applied to phased array antenna and its sounding rocket experiment, in: Proceedings of the 54th International Astronautical Congress, 2003. ], the second is to test the retrodirective antenna system to correct the distortion of the structures in a long range from space to the ground as mentioned above and the last is a microgravity test of the crawling robots on the deployed mesh. The payload section is composed of four sections. The mesh is installed at the top section and the two robots are in the box at the second section under the mesh. The daughter sections at the third section are attached to the mother section, while the momentum wheel is stored in the bottom section. The telemeters and the timer are in the CI section under the payload one. The three sections above the daughter ones are covered by a nose cone. The rocket motor was separated from the payload section to reduce the momentum of the payload, while the nose cone was released after the launch. The payload section was precisely stopped to spin by the momentum wheel for the deployment of the mesh. The mesh would be tangled in case the spinning of the payload section could not perfectly be stopped. The three daughter sections were separated by springs to deploy the mesh installed on the top of the mother section. The daughter sections might be bounced toward the mother section without a position control. Therefore the daughter section had a gas jet to stop the rebound and keep the strength of the mesh. The microwave transmitters were turned on to radiate the microwave toward the ground according to the pilot signal transmitted from the ground station. These transmitters had a retrodirective antenna system to control precisely the direction of the microwave toward the transmitting antenna of the pilot signal. The retrodirective antenna system can decide the output phases of the microwave by conjugating the received phases of the pilot signal. The two robots started to crawl toward the separated daughter sections on the mesh after the deployment. [Copyright &y& Elsevier]

Abstract: Several of the central issues associated with the eventual realization of the vision of solar power from space for terrestrial markets resolve around the expect costs associated with the assembly, inspection, maintenance and repair of future solar power satellite (SPS) stations. In past studies (for example, NASA''s “Fresh Look Study”, c. 1995–1997) efforts were made to reduce both the scale and mass of large, systems-level interfaces (e.g., the power management and distribution (PMAD) system) and on-orbit fixed infrastructures through the use of modular systems strategies. These efforts have had mixed success (as reflected in the projected on-orbit mass of various systems concepts. However, the author remains convinced of the importance of modular strategies for exceptionally large space systems in eventually realizing the vision of power from space. This paper will introduce some of the key issues associated with cost-competitive space solar power in terrestrial markets. It will examine some of the relevant SPS concepts and will assess the ‘pros and cons’ of each in terms of space assembly, maintenance and servicing (SAMS) requirements. The paper discusses at a high level some relevant concepts and technologies that may play r role in the eventual, successful resolution of these challenges. The paper concludes with an example of the kind of novel architectural approach for space solar power that is needed. [Copyright &y& Elsevier]

As an intermediate solution between Glaser's satellite solar power (SSP) and ground-based photovoltaic (PV) panels, this paper examines the collection of solar energy using a high-altitude aerostatic platform. A procedure to calculate the irradiance in the medium/high troposphere, based on experimental data, is described. The results show that here a PV system could collect about four to six times the energy collected by a typical U.K.-based ground installation, and between one-third and half of the total energy the same system would collect if supported by a geostationary satellite (SSP). The concept of the aerostat for solar power generation is then briefly described together with the equations that link its main engineering parameters/variables. A preliminary sizing of a facility stationed at 6 km altitude and its costing, based on realistic values of the input engineering parameters, is then presented. [ABSTRACT FROM AUTHOR]

Mobile satellite services are attracting renewed attention stemming from the FCC ancillary terrestrial component ruling that allows satellite spectrum to be used for integrated terrestrial services in the footprint of the satellite. This attention is focused on the development of dual-mode satellite-terrestrial devices to facilitate hybrid satellite-terrestrial networks intended by the ATC order. The satellite component in these dual-mode devices is best adapted from the air interface chosen for the ATC to optimize form factor, especially for small hand-held devices, mobility management, power efficiency, and a common core network functionality. With the advent of WiMAX as a viable 4G technology, satellite adaptation of WiMAX has been considered for the satellite services coupled with WiMAX ATC. The main considerations for satellite adaptation of WiMAX, relative to its terrestrial counterpart, are reduced link margin and longer transmission delays - both absolute delay from the center of a spot beam to the satellite and differential delay between the beam edge and the beam center to the satellite. These considerations suggest adaptation of the sub-channelization schemes, the frame synchronization methods, and the ranging process in WiMAX to make it operable over satellite, while keeping the general framework of the WiMAX protocol stack intact, thereby facilitating the incorporation of S-WiMAX into a common baseband processor with terrestrial WiMAX; this allows S-WiMAX to be added to terrestrial WiMAX devices with minimal cost and form-factor impact. Methods for these adaptations are considered here. [ABSTRACT FROM AUTHOR]

Spherical solar cells are claimed to have some advantageous characteristics superior to those of ordinary planar solar cells. The most significant one is that the spherical solar cells have no directivity to light. This paper examines the characteristics based on geometrical considerations. The authors prove that a single spherical cell has no directivity as a whole. In practical use, many cells are used in an array configuration, where an individual cell receives the shadows cast by other cells around it. The adjacent shadows, so named in this paper, cause directivity. Their effects are evaluated geometrically and the theoretical considerations are verified through experiments. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(6): 34–46, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10119 [ABSTRACT FROM AUTHOR]

Footprint patterns can be efficiently synthesized by means of planar arrays with hundreds or thousands of elements: an efficient combination of Woodward-Lawson and Orchard-Elliott-Stern roots optimization procedure is suggested. This hybrid technique is applied to a footprint covering Europe by using planar arrays with isotropic elements and linearly polarized circular patches. The proposed method keeps under control both the side lobe and ripple level of the synthesized pattern. [ABSTRACT FROM AUTHOR]

This paper is concerned with the active vibration control of a grid structure equipped with piezoceramic sensors and actuators. The grid structure is a replica of the solar panel commonly mounted on satellites, which contains complex natural mode shapes. The multiinput and multioutput positive position feedback (PPF) controller is considered as an active vibration controller for the grid structure. A new concept, the block-inverse technique, is proposed to cope with more modes than the number of actuators and sensors. This study also deals with the stability and the spillover effect associated with the application of the multiinput multioutput PPF controller based on the block-inverse technique. It was found that the theories developed in this study are capable of predicting the control system characteristics and its performance. The new multiinput multioutput PPF controller was applied to the test structure using a digital signal processor and its efficacy was verified by experiments. [Copyright &y& Elsevier]

Abstract: Tethered solar power satellite (Tethered-SPS) consisting of a large panel with a capability of power generation/transmission and a bus system which are connected by multi-wires is proposed as an innovative solar power satellite (SPS). The power generation/transmission panel is composed of a huge number of perfectly equivalent power modules. The electric power generated by the solar cells at the surface of each module is converted to the microwave power in the same module. Since the modules are controlled by the bus system using wireless LAN, no wired signal/power interfaces are required between the modules. The attitude in which the microwave transmission antenna is directed to the ground is maintained by the gravity gradient force. The tethered panel is composed of individual tethered subpanels which are loosely connected to each other. This configuration enables an evolutional construction in which the function of the SPS grows as the construction proceeds. A scale model of the tethered subpanel can be used for the first step demonstration experiment of the SPS in the near future. [Copyright &y& Elsevier]

An analysis of problems related to mathematical modeling and control of large space structures (LSS) is performed. The widely used types of LSS models as well as modern techniques of controls synthesis are considered together with problems of their practical implementation. Also further possible ways of LSS control system theory are projected aimed at the control of vibrations and system maneuvers. [ABSTRACT FROM AUTHOR]

This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single-phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out as the best candidates for either single PV module or multiple PV module applications. [ABSTRACT FROM AUTHOR]

This paper presents operational performance results of grid‐connected PV systems in Germany, as collected and elaborated for the Photovoltaic Power Systems Programme (PVPS) of the International Energy Agency (IEA). Performance ratios obtained from 235 PV installations in Germany and from 133 PV plants in other countries are compared and discussed. For Germany, a significant rise in PV system performance and reliability was observed for new PV installations due to higher component efficiencies (e.g., inverter) and increased availabilities.There is a lack of long‐term experience in performance and reliability of PV systems, owing to the absence of monitoring programmes. As an outcome of IEA PVPS collaborative work, Task 2 provides reliable and worldwide monitoring performance data and results (www.task2.org). Technical and operational data is available for system planning and comparison, for teaching and training purposes as well as for future developments of financing schemes (e.g., feed‐in‐tariffs) in order to stimulate the PV market. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Maximum power point tracking (MPPT) is usually used for a solar power system. Many maximum power tracking techniques have been considered in the past. The microprocessors with appropriate MPPT algorithms are favored because of their flexibility and compatibility with different solar arrays. Although the efficiency of MPPT algorithms is usually high, it drops noticeably in case of rapidly changing illumination conditions. The authors have proposed an improved MPPT algorithm based on the fact that the maximum power point (MPP) of solar arrays can be tracked accurately. The principle of energy conservation is used to develop the large- and small-signal model and transfer function for the solar power system. The work was carried out by both simulation and experiment on a current converter, by the digital signal processor (DSP) control, in MPPT mode under different illuminations. The results show that the proposed MPPT algorithm has successfully tracked the MPP in rapidly changing illumination conditions. [Copyright &y& Elsevier]

Examines the space solar power (SSP) as a source of electricity for space-based activities. Estimation on the value of SSP; Definition on the future of SSP; Availability of choices to potential SSP customers in the power supply technologies.

Focuses on the developments in the use of wireless power transmission (WPT) beams in the United States. Applications of WPT; Impact of WPT economics on equipment transient protection, energy storage system costs, and quality of power delivery service; Space policies concerning safety of WPT use; Implications for space solar power satellites and other beamed power technologies.

Proposes a scientific foundation for the effective organization and management of satellite solar power (SSP) system. Interaction of the SSP organization with its political, economic and social environment; Fundamental tasks for the SSP organization and management structure; Policy for the beneficial use of SSP; Role of institutional investment program in SSP.

Examines international legal issues concerning space solar power (SPS) systems. Responsibilities of various agencies on launch license, construction and operation of SPS satellites in space; International legal regulation of space objects in outer space; Liability of Space Solar Power Satellite operators and users.

Focuses on the requirements and options for international cooperation in the development and operation of solar power satellites (SPS) and power receiving plants. Localization of large-scale SPS development and operation; Responsibilities of international organizations in project implementation; International dimensions of the financial aspects of an SPS programme.

Focuses on the importance of international coordination in the implementation of space solar power (SSP) projects. Rationale and basis for international coordination; Approaches toward international cooperation in the area of SSP; Need to forge partnerships between government, industry and academia; Details on the terracing approach to implementation of SSP.

Focuses on the policy challenge and cost-benefit determinants of space solar power (SSP). Role of the scientific community in the determination of energy policy; Technological and economic feasibility, public safety, and environmental responsibility of SSP; Ability of SSP project to deliver an acceptable return on investment for funding entities.