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Most existing space solar power concepts place one or more power stations in geosynchronous Earth orbit (GEO). However, due to the limited availability of GEO orbital slots, it may not be feasible to locate a power station in GEO. To overcome this limitation, this paper presents a system analysis for a space solar power system that incorporates a constellation of power stations in a 20,184 km altitude equatorial medium Earth orbit (MEO). The orbiting power stations are based on the Caltech Space Solar Power Project architecture. The constellation consists of multiple power stations in a shared equatorial MEO each transmitting to a non-equatorial receiving station. The analysis assumes a one-to-one correspondence between the number of power stations and the number of ground stations. Like a GEO-based system, this constellation architecture enables a MEO-based system to provide near continuous power (outside of eclipse) to each ground station. It is shown that a MEO constellation with three or more power stations provides comparable transmission efficiency to a GEO-based system. The Levelized Cost of Electricity (LCOE) is then computed for MEO systems with three, four, and five power stations and compared to the LCOE for the GEO-based system. Ground station area is identified as a significant contributor to the LCOE for the MEO-based systems. The system analysis shows that a MEO constellation with as few as four power stations has an LCOE comparable to GEO, and hence, it is concluded that MEO is a viable alternative to GEO for space solar power.

This paper demonstrates the analysis of a long-distance high-power microwave wireless power transmission (MWPT) system based on asymmetrical resonant magnetron and cyclotron-wave rectifier. In the system, the novel magnetron with the asymmetrical resonant cavity, the straps, and the output loop coupling circuit can effectively promote the beam–wave interaction, suppress the mode competition, and enhance the output coupling, which results in a 400 kW output microwave power with a conversion efficiency of 45%. The transceiver Cassegrain antenna system with its simple structure, high conversion efficiency, and high power capacity can attain an integral power transmission efficiency of 2.6% at 10 km distance. The cyclotron-wave rectifier with high efficiency and single-tube high power capacity can achieve 85% microwave to DC conversion efficiency. Finally, the long-distance high-power MWPT system can achieve 8.5 kW DC power with about 1% DC–DC transmission efficiency at the operating 2.45 GHz frequency and for the 10 km distance. Such a system is likely a potential and attracting solution to remotely power the fuel-free aerial vehicle from the ground, can also provide electrical power to an isolated mountain top or an island, and even an alternative to transmit the power from space solar power satellite in geostationary orbit to the ground.

This article presents the concept that Space Elevators enable space solar power (SSP) architecture. An SSP constellation will significantly impact the climate change equation by slowing the increas...

The market for space solar power (SSP) is developing. This analysis utilizes a case study of SSP for remote mine operations to determine its economic feasibility. We employ a discounted cash flow (DCF) evaluation and then assess the sensitivity of the DCF model to changes in its underlying assumptions. The results indicate that there are scenarios for SSP where it is considered a viable power alternative. Further, a discussion of the assumed manufacturing and transportation costs decreases to expand the market is given.

Space Solar Power Station (SSPS) is a giant spacecraft to collect space solar energy and transmit electric energy to the ground by using the wireless transmission technology. As a concentrated space solar power station, SSPS via the Orb-shape Membrane Energy Gathering Array (OMEGA) system is comprised of the concentrator subsystem, the photovoltaic array subsystem and the transmitting antenna subsystem. In this manuscript, the comprehensive study on the coordinate kinematic among subsystems is carried out. Firstly, kinematic analysis and dynamic analysis are conducted. Secondly, under the condition of ideal attitude, the influence of the moving condition of the Photovoltaic (PV) array on the overall system is studied. Finally, the control ability for the deviation attitude caused by the acceleration process of the photovoltaic array is studied. The simulation results demonstrate the serious influence of the angular acceleration of the photovoltaic array on the system's attitude and the validity of the designed attitude control system.

In this study, a new method of using giant magnetostrictive actuator (GMA) to control the structural vibration of a space solar power station (SSPS) in orbit is proposed. The coupling dynamic model of SSPS, which is simplified into an Euler–Bernoulli beam with both free ends, is established in a Hamilton system. A GMA, which has a large strain coefficient, fast response, and strong stability, is coupled to the surface of an SSPS for vibration control. This work particularly considers the coupling effect of vibration–attitude and the complex space environments, such as sunlight pressure and thermal shock, to improve the computation accuracy. Simulation results indicate that GMA has excellent performance in the vibration control of space solar power station. Moreover, GMA can also suppress the attitude changes due to the coupling effect. This study contributes to the stable operation and attitude calibration of the space solar power station, and provides a new reference for the research of dynamics and control of large flexible spacecraft in complex environments.

In this paper, full-spectrum selective thin film based photonic cooler is proposed for passively cooling solar cells of the space solar power station via orb-shape membrane energy gathering array concept (SSPS-OMEGA). The photonic cooler is designed and made of periodic one-dimensional photonic crystal that can reflect solar radiation selectively and enhance heat radiation to the outer space while maintaining its solar transmission in photovoltaic (PV) conversion band (0.4–1.6 μm). The opto-thermo-electrical model is established to evaluate the cooling effects of photonic cooler on solar cells under different incident angles and concentration ratios. The results demonstrate that designed photonic cooler is insensitive with the incident angle, and can effectively reduce the temperature of solar cells by 30 °C at least, indicating a 1.4% increase in solar cells efficiency and 93 MW increase in power output of a 2 GW SSPS-OMEGA system. The photonic cooler also exhibits excellent temperature control characteristic in sandwich module. Results indicate that the proposed photonic approach could be applied to advance the space thermal control technology and exploit the space solar power.

Energy conservation is the basic requirement of energy independence. Due to increased global warming, environmental planning becomes important factor for development. Space based solar power technology will help to achieve sustainable goals and for environmental planning by fulfilling requirement of energy. Hence Space Based Solar Power research has become one of prominent research work in the Aerospace domain. In SBSP, solar energy is normally collected by solar collectors or light structures of solar arrays and electronics devices convert it in some other form of energy i.e. microwave or laser for sending it on Earth. Microwave energy source is safer to living beings than other energy resources. Considering this things, the idea of generating solar power from space have attracted many space enthusiastic people for doing new innovations. This paper reviews cost effective technologies for Space Based Solar Power, orbital parameters which will affect on launching cost and efficiency and use of traditional Japan’s design method i.e. Origami for Space Based Solar Power.

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.

The Space Solar Power Satellite (SSPS) is a promising project to solve the energy crisis on earth. In this paper, a secondary concentrator design of an updated SSPS-OMEGA concept is proposed aiming at the problems existing in original SSPS-OMEGA concept, such as high power transmission through power brush, thermal management of the photovoltaic (PV) cell arrays and special requirements for the concentrator film brought by the inside placed transmitting antenna. Firstly, the updated concept with a secondary concentrator, a disc PV cell arrays and outside placed transmitting antenna is illustrated and main parts of it are described. Secondly, a design methodology of the secondary concentrator is presented. The characteristics of spherical concentrator are simply described. The generatrix geometry of the secondary concentrator is described using Bezier curve, and the performances of optics and energy density distribution on PV cell arrays are evaluated using the Monte Carlo Ray Tracing method. After that, a mathematical optimization model is established and the Particle Swarm optimization is used to obtain better configuration of secondary concentrator, solar energy collection performance and energy density distribution on PV cell arrays. Finally, the optimal generatrix geometry of secondary concentrator and energy density distribution under different orders of Bezier curve are investigated, the result shows that the effective solar energy collection and solar energy collection can be up to 81.14% and 87.06% respectively when the order of Bezier curve is 5. Moreover, a further energy density distribution optimization is conducted and the relative non-uniformity index of 0.4 is realized.

In this paper, high-contrast asymmetric transmission film based on periodic one-dimensional photonic crystal with tunable air layers is presented for the spherical concentrator of the orb-shape membrane energy gathering array based space solar power station concept. As the thicknesses of the air gaps in the photonic crystal structure are precisely controlled, the optical transmission properties of the photonic crystals structure dynamically vary, allowing transmission of propagation waves in the forward direction but reflection in the reverse direction. The geometric parameters of the proposed photonic crystal structure are optimized to obtain both high forward transmittance and reverse reflectance over a broad operating wavelength range from 400 nm to 1200 nm and wide angle of incidence from 0° to 60°. The numerical simulations demonstrate that the average forward transmittance, reverse reflectance and the total solar ray collection ratio of the optimal structure amount to 99.3%, 95.2% and 94.5%, respectively.

Considered a proposal to combat global warming, which consists in placing the creation of information in near-earth space. It is shown that instead of a space solar power plant that transmits energy to terrestrial consumers, it is more profitable to organize an orbital territorial-production complex, in which a new information and communications energy production cycle is implemented: the energy received from the Sun is used on site to create and store valuable information, and instead of an unused technology of wireless energy transmission to Earth, using a well-functioning space communication technology. Using the simplest mathematical model, it was demonstrated that the profitability of orbital information must be considered taking into account the anthropogenic impact on the climate of ground data centers. The dependence of the profitability of an information orbital product in comparison with a ground-based analogue on the cost of emission quotas for waste heat and greenhouse gases is discussed.

The space solar power station is a gigantic power satellite to provide the earth with continuous energy. The front-end system of space solar power station, solar concentrator, has significant influences on the optical performance. Regarding the proposed orb-shaped membrane energy gathering array scheme, this paper deals with the construction strategy of its large-scale spherical concentrator to reduce the complexity of manufacturing and improve the optical properties. The optical principle of the spherical concentrator is described and the spatial motion characteristic is presented. A novel construction strategy for the large-scale concentrator is proposed via partitioning octahedron on the sphere and polygonal partition. This paper evaluates the optical performance of the concentrator constructed by the novel strategy using ray tracing method. Performance parameters such as optical concentration ratio and collection efficiency are obtained. Comparison with the other strategies are also implemented. In addition, influence factors such as the sun's non-parallelism, the tracking precision, the orbital periodic motion, and the potential blockage effects of microwave transmitting antenna and supporting structure are mathematically discussed and evaluated. The numerical results indicate that the proposed strategy achieves a high collection rate, a small efficiency fluctuation, appropriate energy distribution, and relatively small splicing modules, which is conducive to improve optical performance and decrease difficulty in manufacturing.

In microwave power transmission (MPT) applications, the problem of maximizing the transmission efficiency has been extensively studied. However, to reduce costs, the power transmission capacity needs also to be considered. Moreover, to ensure safety, the peak radiation level at the edge or outside the rectenna must be taken into account either. To deal with these problems simultaneously, a multiobjective optimization design method of aperture illumination for MPT is proposed. Subsequently, a multiobjective grey wolf optimizer is developed and employed to solve the formulated problem. This new design approach provides antenna engineers with a set of tradeoffs among multiple goals, and therefore, the best compromise can be selected for a given application. To verify the effectiveness of the proposed method, numerical experiments on continuous aperture with different Fresnel parameters are conducted first. Then, the obtained results are applied to a space solar power satellite model, which demonstrates the validity of the proposed method. Finally, the effectiveness of the proposed method is further confirmed via numerical experiments on array antennas.

We present a detailed design treatment for a concentrating photovoltaic mini module subsystem with a specific power of up to 4.1 kW/kg for integration into a space solar power system. Concentrating designs are required to achieve specific power over 1 kW/kg with current high-efficiency III-V multijunction solar cells. The 15 sun, linear concentration concept detailed here reduces the system mass by replacing cell and radiation shield area with ultralight carbon fiber reinforced polymer (CFRP) optics. Reducing the cell size to 1 mm width as well as careful optimization of cell architecture and CFRP material and thickness are critical for maintaining cell temperatures under 100 C despite the concentration. We also describe ultralight multilayer optical coatings to increase the thermal emissivity of the concentrator surfaces and enhance radiative transfer for cell cooling, which is a critical technological component of the total system design.

Space is a warfighting domain. States around the world are proliferating technologies for space warfare. The design concept of an inflatable spherical solar power satellite, known as the Power Star...

SPS-ALPHA as the most innovative and practical concept of Solar Power Satellite (SPS), has been widely concerned in the world. It adopts axisymmetric sigmoid curve-based/cocktail shape as the entire structure composed by several thousands of hexagonal “Reflectors and Deployment Modules” (RDM) that enables extremely high modularity and low cost of machining/space transport. SPS-ALPHA system, on the whole, can be treated as a dense array concentrated photovoltaic (DA-CPV) system. The blocking shadow effect and cosine effect of ray path exist that make the optical efficiency fluctuate with different tracking angles, resulting the trade-off exists between optical efficiency and irradiance uniformity. The current study aims to find the optimal design parameters of RDM when high optical efficiencies and stable irradiance distribution are both achieved for effective PV layout design. To meet this target, Ant Colony Optimization (ACO) algorithm combined with dynamic source-target mapping was adopted to find suitable aiming vectors of modular reflectors. The optical transmission characteristics under different incident degrees were investigated using a two-step Monte-Carlo ray tracing (MCRT) method. Afterwards the optimized results and sensitivity analysis for RDM would be undertook. The article can provide basic data and reference for engineering constructions of SPS-ALPHA in next step.

The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing interest. High concentration photovoltaic systems (HCPVs) combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion efficiencies. The mathematical model for triple-junction solar cells, having a higher efficiency and superior temperature characteristics, was established based on the one-diode equivalent circuit cell model. A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this study. The GaInP/GalnAs/Ge triple-junction solar cell, produced by AZUR SPACE Solar Power, was also used in this study. The solar cells produced by Shanghai Solar Youth Energy (SY) and Shenzhen Yinshengsheng Technology Co. Ltd. (YXS) were used as comparison samples in a further comparative study at different concentration ratios (200X–1000X). A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic system. The results show that the short-circuit current (Isc) and the open-circuit voltage (Voc) of multijunction solar cells increases with the increasing concentration ratio, while the cell efficiency (ηc) of the solar cells increases first and then decreases with increasing concentration ratio. With increasing solar cell temperature, Isc increases, while Voc and ηc decrease. A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%, which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.

Considering the limitation of selecting several neighbor sensors in a local region similar to just single one, namely redundant information, a sensor placement algorithm for structural health monitoring is proposed based on sub-clustering strategy, in order to improve the performance of sensor configuration with less redundancy. According to the significance of redundancy, the proposed novel redundancy elimination model considers global and local effect to overcome the previous limitations in sensor distribution. Based on the sub-clustering strategy, the redundancy elimination model reflects the sensor configuration in each sub-clustering and overall structural field. The presented sub-clustering strategy for sensor placement includes three main procedures: sub-clustering algorithm, its check step and smallest enclosing circle method, thus the accuracy can be guaranteed. Combining the effective independence method with normalization and weighting factor, the proposed sensor placement algorithm can balance performance and redundancy by using genetic algorithm, which is more competitive to reduce the order difference between the two objectives. Finally, the effectiveness of the proposed redundancy elimination model is verified by a simple example, and another two engineering numerical examples including space solar power satellite and re-usable launch vehicle are applied to demonstrate the validity of the proposed sensor placement algorithm respectively.

Recent debate (Clack v. Jacobson, 2017) argues the feasibility of 100% terrestrial renewables (wind, water, solar) by 2050, on the premise of restricting world consumption to 2012 levels (∼12 TW-years). Given the expected population rise by 3 billion over the same time frame, and the correlation between prosperity and energy availability – are we to impose energy equality, requiring some to reduce consumption by 87%, or are we to condemn the majority to relentless poverty? Choosing neither implies ever-increasing carbon emissions and the risk of catastrophic climate change. Nuclear fission is one energy technology which could be expanded to provide sufficient carbon-free power, but faces widespread opposition from public fear and distrust. Future terrestrial fusion is another, but first pilot operations are not expected until 2050 – which may be too late. We could make much better use of one existing fusion power source, our Sun. The fundamentals of Space Solar Power (SSP) are well understood and could lead to a world of energy abundance; the deliverable energy from just a 10 km geostationary (GEO) band exceeds 570 TW-years – enough to supply ten billion people at six-times current US per-capita levels. Despite this, SSP has languished for fifty years. GEO is one of few candidates for baseload power, but physics dictates a kilometre-scale microwave transmitter irrespective of the power delivered – hence economics favours the multi-gigawatt (per-satellite) engineering limit. Given the complexity of the differentially rotating solar collector, sub-gigawatt SSP suffers both economically and technically, with different solutions required at different scales – which has led to exorbitant (hence prohibitive) start-up costs. CASSIOPeiA breaks this non-scaling paradigm by eliminating the rotating interfaces; all SPS subsystems are able to share one lightweight modular structure, with near-invariant areal power density from sub-megawatt to gigawatt systems. With additional fixed mirror concentrators, CASSIOPeiA can also be expanded into the multi-gigawatt regime. CASSIOPeiA's unique beam-steering capability facilitates baseload delivery from alternative, closer orbits, with the possibility of single payload deployment requiring no on-orbit assembly. By starting with sub-megawatt, near-term stratospheric station-keeping platforms – with retrieval, servicing and transfer of gained knowledge – the era of SSP may commence at much lower risk and expense.

The article is devoted to the creation of a control system for the orbital segment of a space solar power station and the main principles of its creation. The simulation of the functioning of a demonstrational space solar power station operating in an elliptical orbit with the energy transfer in low orbit sections has been conducted and a high-precision control of the spacecraft at low altitudes has been considered. The result of the performed studies is the computational confirmation of the capabilities of the measuring, calculation and orientation to provide the required accuracy of the spacecraft orientation for demonstrating the energy transfer from orbit to the receiver system. The obtained results give grounds for the construction of a demonstrational space solar power station in the low orbit.

Spatial lattice structures are widely applied in engineering fields attributed to their superiorities in weight and reasonable stress. It is essential to select the best sensor placement layout for structural health monitoring and safety purposes, yet it is neither realistic nor efficient to place sensors in every location possible on the structure. To meet the strong requirements for optimal sensor placement in spatial lattice structure, this paper aims to investigate a combined objective function based on effective independence method and three dimensional redundancy elimination model to balance between optimal sensor placement performance and elimination in redundancy. To eliminate redundant information and resource waste caused by the clustered sensor distribution, the three-dimensional redundancy elimination model is constructed with the consideration of nearer nodes and overall sensor distribution ranges in three-dimensional cases. In addition, the combined function is constructed by giving the two component functions equal significance using weighting factors and normalization, and solved by genetic algorithm. Finally, the proposed method for spatial lattice structure is supported by three numerical examples including a simple lattice structure, a ground spatial truss structure and a space docking modular in space solar power satellite.

A Fresnel concentrator with fiber-optic bundle based space solar power satellite (SSPS) is proposed as an innovative design in this paper. It consists of a flat Fresnel lens array for solar concentration, fiber bundles to transport the condensed sunlight to the photovoltaic panel and a highly modular sandwich module for power generation/transmission. Operating principle, structure configuration and efficiency of the system are presented in detail. Also, Fresnel concentrator with a secondary homogenizer is designed to obtain high concentration ratio and good irradiance uniformity on the solar cell. Lastly, to maintain the temperature fluctuation within a design requirement, the thermal analysis of the sandwich module is investigated. The obtained results demonstrate the feasibility of the proposed SSPS design.

With the rapid development of the world’s aerospace technologies, a high-power and high-reliability space high-voltage power supply is significantly required by new generation of applications, including high-power electric propulsion, space welding, deep space exploration, and space solar power stations. However, it is quite difficult for space power supplies to directly achieve high-voltage output from the bus, because of the harshness of the space environment and the performance limitations of existing aerospace-grade electronic components. This paper proposes a high-voltage power supply module design for space welding applications, which outputs 1 kV and 200 W when the input is 100 V. This paper also improves the efficiency of the high-voltage converter with a phase-shifted full-bridge series resonant circuit, then simulates the optimized power module and the electric field distribution of the high-voltage circuit board.

With the development of greenhouse technologies using saltwater for evaporation and cooling, irrigation of arid regions may be possible with proper power sources. We present here space-based solar power (SBSP) as a way of expanding the irrigation network and demonstrating the relevant technologies. Once implemented, SBSP could be used for other terrestrial applications as well as space missions on the Moon or Mars.

This paper presents the conceptual design and analysis of modern space solar power satellite and space rectenna system. There is a challenge to collect and transmit large amount of energy from space to Earth using microwave power transmission technology without the interference with communication satellites such as industrial, scientific, and military operation systems. This study focuses on low Earth orbit (LEO) location of the space satellite system for maximum efficiency. Microwaves of 2.45 GHz and 5.8 GHz frequency are investigated to determine the most efficient system used to transmit the electric power from the space satellite to the rectenna. The space solar power system uses a satellite placed on an orbit to collect the solar energy instead on earth’s surface. Research found space-based solar power to be uneconomical, but new developments have renewed interest for space solar power exploitation. The space-based section of the system consists of a constellation of solar energy-collecting satellites or SUNSATs that collect solar power and transmit it at a suitable frequency to the rectenna on Earth.

According to the space solar power satellite development strategies in China, a mega-watt (MW)-level SSPS on geostationary Earth orbit (GEO) demonstration will be carried out after 2030. Microwave power beam steering must be considered for the demonstration. Beam steering methods are reviewed for microwave power transmission applications. Then beam steering requirements are investigated for MW-level SSPS demonstration. Beam steering technology is proposed for the demonstration with consideration of MW-level microwave power transmitting subsystem design.

Based on the current technical approaches, a microwave power transmission demonstration system has been proposed to simulate the operating mode of MPT for the future Space Solar Power Station (SSPS). Several key technical parts are emphatically considered in the system design, namely high efficiency microwave power amplifier, transmitting antenna array, rectenna array and beam steering control technology. Each module of the microwave power transmission system is designed and optimized in this paper. The operating frequency of the MPT system is 5.8 GHz. The diameters of transmitting antenna and rectenna arrays are about 1.2 m and 2 m respectively, correspondingly the transmission distance is about 55 m. The transmitting microwave power is about 1600 W, the output DC power is expected to be larger than 300 W, and the accuracy of beam control is better than 0.4°. This work can provide technical support for the MPT system demonstration towards SSPS.

Based on constructing planning of Space Solar Power Satellite (SSPS) in China, transmitting antenna aperture is about 200m in megawatt SSPS system with technological development in future. According to the constrained condition of transmitting and receiving antenna, with respect to contradiction beam collection efficiency and construction cost that are both associated with receiving antenna aperture, power density distribution in receiving antenna of different size is analyzed and studied. And high efficiency requirement of rectifier because of power density' distribution difference is emphasized. Simulation results show that reasonable size of receiving antenna in megawatt SSPS system is 5km, while only one type of diode and same rectifier are adopted in whole antenna area. This parameters should be supported systemic optimization for megawatt SSPS. Finally, feasible techniques suit for megawatt SSPS of lower power density is proposed.

A Space Solar Power System (SSPS) comprises many parts, in a space segment and a ground segment. In order to construct an SSPS, many parts have to be launched to space using rocket vehicles. All these subsystems must complete a phase of basic research, before starting the development phase. This paper presents the basic SSPS research in Japan on selected topics. Spacetenna construction is discussed from both viewpoints of mechanical structure and electrical performance. Beam-forming using phased array antennas is explained. For launch, a new type of microwave rocket is introduced. The details and present achievements of each topic are written by a representative of each research group.

Space Solar Power (SSP) is the dream of limitless clean solar fusion electric power, beamed down to the terrestrial power grid. Periodic spikes of media attention to this dream correlate well with various initiatives for other strategic objectives, but there is also an underlying thread of serious research towards the dream. The hurdles to viable SSP are first summarized. The Space Power Grid and the Intensified Conversion Architecture (InCA) are explained in the above context, and the technical obstacles defined. Recent progress is outlined. The target is still a Specific Power of 1 kWe delivered to the terrestrial grid, per kilogram placed in orbit. Present architectures do not exceed 0.21 kWe/kg, but claim viability by projecting low material costs and extremely low launch costs. Photovoltaic convertor mass and size scale linearly with power, so that at relevant scale the probability of catastrophic collisions becomes prohibitive. The InCA promises Specific Power well over 1 using ultralight collector-concentrators and Brayton cycle conversion. The SPG is a synergistic avenue towards SSP where power is transacted through Space to turn renewable power plants into baseload suppliers, and set up a market for beamed power, preceding mass production. Breakthroughs in millimeter wave and/or laser conversion from sunlight and to grid power, are needed before a viable SSP architecture can be built. Several developments have advanced along needed directions. A Space-based market, led by military applications, may be a game-changer.

The all-electric aircraft (AEA) is a fully battery powered aircraft that does not require jet fuel for its operation. The battery’s energy capacity is much lower than that of jet fuel. Thus, AEA will be commercially viable, if mid-air recharging (MAR) is implemented. Authors have studied MAR technology needs in previous researches. This paper studies atmospheric, rain and cloud attenuation impact on wireless power transfer (WPT). This study impacts the design of rectennas at both AEA and space solar power (SSP) satellite that determines the minimum size of AEA. The International Telecommunication Union attenuation models are considered. Simulations are conducted to study the selected attenuation effects on WPT for the millimeter-wave frequency range of 30GHz, with respect to different cruise altitudes and locations. This study confirms that rain and cloud attenuations are negligible when the cruise altitude is over 6km. The atmospheric attenuation is approximately 10 times higher than that of rain and cloud. However, rain attenuations have a significant impact at low altitudes. In general, atmospheric, rain and cloud attenuations are not high but not insignificant.

All-electric satellites have been developed all over the world. These satellites achieve high fuel efficiency by replacing chemical propulsion systems with electric propulsion (EP) systems. It is possible to increase the payload and prolong the life of the satellite. In the future, it is expected to construct large-scale structures like Space Solar Power Systems which provide the earth with continuous energy in the space. The EP system consists of a Power Processing Unit (PPU) and Hall thrusters. The PPU’s mass is twice that of the hall thrusters. JAXA is studying the anode power supply of the for realizing the light weight PPU. The anode power supply is required to have high efficiency and wide range boost ratio. In this paper, an LLC resonant converter as the control topology of the power supply is evaluated. Two types of converters are designed using #1: 50V or #2: 24 to 32V primary voltage. The converter #1 realized 95% efficiency at 1kW. The converter #2 can output 300V at 93.1% maximum efficiency, and it can operate at about 5.5 pt loss in 8V of the primary voltage fluctuation. In this paper, it is revealed that LLC resonant converter can contribute to realize light weight of the PPU.

This paper presents the review and analysis of modern space solar power satellite system and space rectenna. There is a challenge to collect and transmit large amount of energy from space to earth using microwave power transmission technology without the interference with communication satellites such as military operations systems and aircraft radar systems. This study focuses on Low Earth Orbit (LEO) location of the space satellite for maximum efficiency. Microwaves of 5.8 GHz frequency with efficiency of 85% will be used to transmit the electric power from the space satellite to the rectenna. Space-based solar power system is different from the current solar power collection methods. The space solar power method uses a satellite placed on an orbit to collect the solar energy instead of on earth's surface. Research found space-based solar power to be uneconomical but new developments have paved ways for space solar power exploitation. The space-based section of the system consists of a constellation of solar energy collecting satellites called SunSats that collect solar power and transmit it through a suitable frequency to earth. The ground station of the system consists of large receiving antennas known as rectennas which convert the microwave frequency into DC power. The DC power is then transformed into AC and injected into the electrical grid.

In this paper, the object detection technology based on deep learning is applied to the assembly process of space power station simulation, which can provide assistance for the attitude adjustment and navigation of the aircraft through the detection of some components. Firstly, the 3D modeling and rendering of the space power station are carried out, on which the image dataset is collected and established. Then, based on the YOLOv3 network, we improve the structure of feature extraction. By fusing the information of shallow and deep features, we can improve the detection ability of the network for different scale objects. Qualitative and quantitative experimental results show that the improved YOLOv3 network can accurately and effectively detect the key components of the Space solar power station.

A plausible concept for a first space Solar Power Satellite demonstration is presented. The designed satellite is similar in size to a direct broadcast communication satellite. It uses a 40 kW solar array to provide power to a 20 kW IR laser. Because the dispersion of the eye safe 1.6 micron IR laser beam is much less than the dispersion for a microwave beam, the spot size on earth from GEO is only tens of meters in diameter rather than several km. Even though the laser intensity on the ground will be low, nevertheless, modules with concentrating lenses at the ground can boost the intensity on IR GaSb PV cells and could still deliver 8 KW of solar power 24 hours per day for a first space to ground solar power satellite demonstration.

The solar power satellite (SPS) concept is an elegant solution to the challenge of providing large-scale energy for humanity: a large platform, positioned in space in a high Earth orbit, continuously collects and converts solar energy into electricity. SPS-ALPHA is composed of a large number of small modules, which enables the modularity and lower cost of machining/space transport. Until now two options of SPS-ALPHA have been proposed, the Mark-I version (sigmoid-curve-based shape) and the Mark-II version (conical shape). The current study aims to find the optimal design parameters of the reflecting modules for these two versions where high optical efficiency and a stable irradiance distribution are both achieved for an effective photovoltaic layout design. To meet this target, the ant colony optimization algorithm, combined with dynamic source–target mapping, was adopted to find the optimal aiming vectors of the reflectors. The optical transmission characteristics under different incident degrees were investigated using a two-step Monte Carlo ray tracing method. The received heat flux distribution and error analysis of the two structural versions are compared as well. This article can provide basic data and a reference for engineering constructions of SPS-ALPHA for the next step.

This paper presents power-optimal guidance for a planar space solar power satellite (SSPS). Power-optimal guidance is the attitude trajectory that maximizes the solar power transmitted by the SSPS. Planarity is important because it couples the orientations of the SSPS’s photovoltaic and antenna surfaces. Hence, the transmitted power depends on the relative geometry between the SSPS, the sun, and the receiving station. The orientation that maximizes power transfer changes as this relative geometry changes. Both single- and dual-sided SSPS architectures are considered. A single-sided SSPS has one photovoltaic surface and one antenna surface. A dual-sided SSPS is a single-sided SSPS with at least one additional photovoltaic or antenna surface. Geometric arguments show that a dual-sided SSPS has superior performance to a single-sided SSPS. Power-optimal guidance is then presented for the special cases of SSPSs in geostationary Earth orbit, medium Earth orbit, and low Earth orbit transmitting to an equatorial receiving station at the time of Earth’s vernal equinox. These examples emphasize important solution properties, including the need for large slew maneuvers, and they show that, even though system efficiency decreases as orbit altitude decreases, reduced path losses actually increase the amount of received energy per unit aperture area. This has significant system implications for future space solar power missions.

Electrical power generation is an important aspect of a successful space mission. Bigger spacecraft with large solar panels are able to generate enough power to perform their missions, but there are other mass and volume limited spacecraft that are also power-limited in their mission capability. Examples include small satellites with high-power payloads and deployed platforms such as rovers on the lunar surface. These platforms have limited available solar panel area and may have to operate in extended eclipse conditions. For these missions, a power beaming satellite can augment their power generation, greatly enhancing mission capabilities. Space Solar Power (SSP) systems have been investigated for over 50 years. Its potential to deliver energy to any location or to remotely power unmanned vehicles is worthy of development. Recent demonstrations have shown the practicality of transferring power in the terrestrial environment. Two major methods to beam power have been proposed using either microwave or laser energy. Microwave energy has minimal losses due to atmospherics and has a slightly better end-to-end transfer efficiency. When applied to space assets, where mass and volume is a premium, microwave system has a major drawback of requiring a dedicated receiving system just for energy reception that does not serve any other purpose. In contrast, the receivers for laser power beaming are solar cells where the receiving panel can also utilize the natural sunlight to generate electrical power. For space systems where the primary power generation is achieved using solar panels, this method of power beaming is ideal. This method becomes especially attractive for satellite-to-satellite or satellite-to-rover power beaming. Most modern space systems use multi-junction solar cells to better utilize the entire solar spectrum. Since a monochromatic laser does not match the solar spectrum, a multi-junction solar cell would not generate power efficiently from a single wavelength laser. This paper addresses the design for a polychromatic laser system to beam power to a multi-junction solar cell for space applications and the power levels needed of the different laser wavelengths to optimize the spectral response of a space-grade solar cell. Since the wavelengths will be selected to best match the spectral response of each junction and the currents matched across all junctions, the efficiency of the multi-junction cell would increase to 51% without concentration while still being able to use the solar spectrum for power production. Three matched lasers were able to beam power at a 38% increase over a single wavelength laser.

We present a lab demonstration of the packaging and deployment of an ultralight space structure prototype composed of thin shell longerons and battens. The prototype is integrated with a thin polyimide membrane which serves as mass representative of multi-functional elements that could be integrated into this type of deployable, such as integrated power collection and wireless transmission tiles for space solar power. A deployment mechanism using actively controlled pressure to package and deploy this structure ensuring its integrity is described. The deployable structure and deployment mechanism designs are scalable to 60 m X 60 m structures. The structure's mass scaling to larger sizes is described.

To satisfy the increasing demand for power and reducing CO2 emission, the future generation system must meet the demand, reliability, efficiency and sustainability. This has increased the generation of power by using solar, wind, tidal, and many more. A wireless power transmission using microwave is a system which comprises satellite based solar power system (SPS), microwave generator, microwave transmitter (magnetron) and microwave receiver (rectenna). The DC power received on earth is converted into AC for various useful purposes. This paper gives a comprehensive study of various components of satellite based SPS and projects this technology as a vital source of power generation in future. Wireless power transmission is also be done by mutual induction which provides various charging facility.

This paper investigates the use of thin phased array tiles for the microwave transmitter portion of a space based solar power satellite. Tile phased arrays have been developed for avionic radar, and for 5G telecommunications. This paper attempts to answer the question: "Will it be possible to use these tile arrays for space based solar power systems?"

Robust space development as usually envisioned by its advocates—the persistent and self-sustaining presence of humans and industry in space—is stymied by a fundamental paradox: for there to be a reason to develop space, there must already be people and industry there. To the extent that space development is a priority for any government or entity, this paradox must be surmounted. Space-based solar power (SBSP) production may represent the best way to overcome this paradox because of the technology's inherent scalability, rising demand for terrestrial clean baseload energy, and potential for self-funding. However, technical, regulatory, legal (domestic and international), and geopolitical challenges to deploying this technology on a large scale remain. In this article, the authors describe how SBSP development can potentially overcome the development paradox and offer an analysis of the challenges to this concept and potential approaches to resolving them. Furthermore, they provide a tentative research and commercialization roadmap for a private-public partnership for SBSP to deliver sustainable space development, identifying relative advantages and disadvantages.

This paper presents several problems about development of Space Solar Power Satellite (SSPS) systematically. Firstly, the importance of developing SSPS to solve the energy crisis of the world is discussed. Secondly, two main categories of SSPS, non-focusing and focusing concepts, are described with the advantages and disadvantages, such as the specific power to mass ratio (energy produced by unit mass), engineering implementation, reliability and so on. Thirdly, recent achievement of SSPS-OMEGA concept proposed by author’s team in 2014 is provided. Finally, future development on SSPS is discussed.