The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector, where various countries are competing in its development. This paper surveys the research experiments and development efforts related to space solar power stations and microwave wireless power transmission technologies worldwide. The objective is to assess the progress and current state of this technological foundation, determine the necessary focus for developing high-power microwave wireless power transmission technology, and provide clarity on the direction of future technology development in these areas. Finally, a distributed space solar power station plan that is immediately feasible is proposed.

With the development of space solar power stations， the demand for high-efficiency and zero-obstruction solar concentrators is increasing. However， the existing technologies still face numerous challenges in terms of spot uniformity and aberration control. To address these issues， an off-axis conjugate point-focusing solar concentrator with a 500mm aperture and a focal ratio of 3 is proposed， along with its optical path optimization method. The concentrator consists of four parts：an off-axis primary mirror， a conjugate mirror， a planar reflector， and a sun-tracking mechanism. The off-axis primary mirror provides the main optical parameters； the conjugate mirror compensates for aberrations； and the planar reflector ensures precise positioning. Geometric construction methods are used to adjust the surface shape of the reflectors， constructing an accurate mathematical model， and analyzing the optical path using ray tracing methods. An optimization function targeting the main aberrations is constructed， and spot diagrams and irradiance maps are used to analyze the focal spot shape variations. By adjusting the reflective surface shapes of the off-axis primary mirror and the conjugate mirror， aberrations are effectively reduced， and the concentration ratio is improved. Detailed optical simulations are conducted under normal incidence and multi-angle incidence conditions to optimize the optical path design. Experiments conducted at an outdoor temperature of -10℃ demonstrate the aberration compensation effectiveness of the system. The optical concentration ratio exceeded 100， and the maximum focal temperature reached 372℃. This study innovatively proposes an efficient off-axis conjugate focusing method， achieving zero obstruction， high concentration ratio， and high precision focusing through multi-level optimization techniques. The results indicate that this method has significant application potential in space solar power systems， providing a new solution for future solar energy utilization technologies.

The current-carrying frictional pair composed of inner raceway， outer raceway，and flexible ring is the conductive core component of the space rotating electrical transmission mechanism. To investigate the effect of vacuum temperature on the transmission performance of flexible rings， rolling current-carrying tribological tests were carried out in the temperature range of -30℃~120℃ in 1×10^-3Pa vacuum. As the temperature increased from -30℃ to 120℃，the steady-state average friction force decreased from 3.96N to 1.48N， and the elastic force decreased from 6.8N to 5.9N. There was no significant change in the average contact resistance and wear amount. Microscopic morphology showed that the wear width increased from 47.37μm to 66.71μm， the roughness of the worn area dropped from 0.45μm to 0.25μm.The extrusion deformation caused by high-temperature softening of materials should be the main reason for the widening of wear marks.Material softening and its concomitant widening of wear marks lead to a decline in the elastic force of the flexible ring.

The space solar energy development and utilization is gradually becoming a reality. In the process of energy transfer from space to the ground， losses are inevitable. If those lost energy could be effectively utilized in space， the efficiency of energy utilization in SSPS（Space Solar Power Station）would be significantly improved. The “Space Computing Project” concept is proposed-a lightweight， large-power， and high-efficiency data processing center is established in space， and the electric energy generated by SSPS is directly used to calculate spatiotemporal data from satellites or other data sources. Providing the highest possible underlying data capability support under limited hardware resources is an engineering challenge that must be solved during the implementation of the Space Computing Project. Currently， there are few effective solutions. The “Soft Supercomputing” platform is designed. This platform is based on a high-performance real-time database software called NoSQLt. It is hardware-independent and with a small size. By using the high-concurrency and high-throughput data support capabilities provided by NoSQLt， the hardware computing capability can be fully utilized， so as to achieve efficient data processing ability with limited hardware resources deployed in space. Many application cases based on NoSQLt have proved the feasibility of Soft Supercomputing platform. For numerical data， a concurrent throughput of 5.3 million transactions per second is implemented on a regular desktop platform， and 1.15 million transactions per second on the Raspberry Pi 4B platform. A new data center energy consumption evaluation index called “Unit Throughput Capacity” is proposed.Performance testing experiments prove that NoSQLt has high performance under limited hardware resources， providing a fundamental capability guarantee for the future implementation of Space Computing Project.

An engineering simplified approach to the general formulation for the dynamics of flexible spacecraft is presented on the basis of the complete second-order differential equations. First, the integral items are simplified based on the translational lumped mass method, and the element inertia and rotational motions for shell element or beam element are omitted. Thus, the complex volume integral computation is transformed to the summation operation of variables multiplied by translational masses. Second, the nonlinear matrix coefficients are simplified to constant matrix based on “the small deformation assumption”, while omitting the impact of the elastic displacements on the position vectors. Therefore, all the items of the general formulation for the dynamics of flexible spacecraft are well preserved, but their computation is remarkably simplified. The approach could be used for the analysis of flexible spacecraft with largeamplitude and complex motions, and further extended from single-body to multi-body in order to solve the dynamics of on-orbit construction structures or space robots/arms. Finally, the approach is verified by multiple numerical examples and an application case.

To predict the working temperature and distribution of flexible solar panels on spacecraft in orbit, an analysis of the thermal environment experienced by the solar wings in outer space was conducted. The variation of heat flow on the front and back of the flexible substrate with the orbital period was calculated. Two typical power generation conditions of the solar cell array-optimal operating point and open circuit state, were considered, and the working temperature of the solar cells and flexible substrate was calculated using the finite element method to study the periodic temperature variations with the orbit. A comparison was made with telemetry data from the space station to validate the accuracy of the model and calculation method. The influence of the thermal-physical performance of various functional areas on the temperature distribution of flexible solar panels was studied by comparing the results under two conditions. The findings indicate that the disparity in absorptivity between the solar cells and substrate could lead to notable temperature gradients at the bonding edges of the flexible substrate, which is a crucial factor that could induce thermal deformation in the flexible substrate.

Due to strong ionospheric distortions and Radio Frequency Interference (RFI)， radio astronomy observation at frequencies below 30MHz is not feasible on earth. And the launched orbital detectors cannot meet the needs of high resolution and sensitivity observation. A lunar based square kilometers radio telescope antenna array is proposed in this paper. And the aspects of scientific objectives analysis， technical index demonstration， and project implementation scheme are detailed discussed. The corresponding technical route and realization way are given too. All of these are aiming at providing strong technical support for the development of space ultra-long wave radio astronomy observation in the future.

The camera extension mechanism needs to obtain and maintain sufficient stiffness and dimensional stability after unfolding and locking, and at the same time, for the demand of high precision and high spread ratio of specific space optical remote sensing camera, a one-dimensional space optical remote sensing camera with high precision, high spread ratio extension support mechanism and high stiffness volute springs is designed to realize the elimination of the hinge gap and the maintenance of high stiffness of the structure after unfolding. The extension support mechanism uses a scroll spring to drive the folding spreading bar to realize the mechanism unfolding, a speed control mechanism to control the speed of deploying, and a hinged positioning surface to locate the hinge when deployed, with the residual driving force of the scroll spring and the tension cable to maintain the stiffness. The unfolding dynamics analysis, modal analysis, unfolding accuracy analysis considering the length error of the member and the hinge rotary gap, and thermal deformation analysis under the working environment are carried out for the unfolding support mechanism. The camera extension support mechanism is completed, and the base frequency of the mechanism is above 20Hz. The ground repeatable unfolding accuracy of the prototype extension mechanism is measured, and the unfolding accuracy is better than ±0.05mm. The performance of the extension support mechanism is good, and it can satisfy the requirements of the special tasks of the space optical remote sensing camera.

As aerospace technology advances, ionic liquid electrospray thrusters (ILET) are gaining attention for their efficiency and stability. This study delves into the performance limits of ILET by simulating the electrospray process, using a coupled electric and flow field approach. Performance parameters are analyzed by using the response surface methodology (RSM), leading to optimal operational and structural parameters. The findings indicate that, with a 20μm emitter diameter, 119.384μm height, 3.45×10^-2nL/s flow rate, and 2188.249V voltage, the maximum thrust is 1.464μN; with a 48μm diameter, 119μm height, 1.9×10^-2nL/s flow rate, and 2600V voltage, the highest specific impulse reaches 1077.543s. The simulation and model results align closely with experimental data, with an error margin within 5%, confirming the model's reliability. Innovatively combining electric and flow field coupling with RSM not only enhances analytical precision, but also opens new avenues for evaluating similar complex systems. Furthermore, this research provides a solid theoretical foundation for ILET's application in aerospace, demonstrating its potential for future space missions.

Aiming at the applied background of low-orbit Walker constellation, a complete satellite network communication system architecture based on a hierarchical clustering routing protocol is proposed, which covers the network layer, data link layer and physical layer. For ease of analysis, a typical model of low-orbit Walker constellation is built firstly. The topological characteristics and the communication visibility between satellites with different orbital phase factors and orbit inclination are analyzed. Then a concept called Virtual Same Orbit is proposed in the paper based on the constellation topology, and a double layer network is built according to the Virtual Same Orbit. Finally, for this double-layer network, the specific schemes are given in the network layer, data link layer and physical layer respectively to achieve information interaction between same-orbit and different-orbit satellites. The communication protocol stack designed in this paper considers the cross-orbit information transmission scheduling problem of Walker constellation, taking into account the transmission efficiency and design complexity, which has certain reference value for the design of other Walker constellation inter-satellite networking systems with similar configurations.

In order to improve the prediction efficiency of GEO electron flux greater than 2MeV one day in advance, a data fusion algorithm based on simulated annealing algorithm and least squares fitting was used to process GOES series satellite electron flux data. A genetic algorithm optimized BP neural network (GA-BP) model was established based on the fused data. The input parameters of the model include solar wind speed, geomagnetic index (including SYM/H, Ap, AU, AE, Dst), electron integral flux greater than 0.6MeV, and historical electron integral flux greater than 2MeV. The time resolution of each parameter is daily average; At the same time, using data from 1999 to 2007 as the training set, the GA-BP model after data fusion was used to predict the electron flux from 2008 to 2010, and the predicted results were compared with those of other classical models. The results showed that using simulated annealing algorithm to project satellite data located in the 75°W area to the 135°W area resulted in smaller data errors and better fusion effects; The prediction efficiency of electron flux greater than 2MeV is 0.863 one day in advance, and the highest prediction efficiency can reach 0.931, which is better than the prediction accuracy of many previous models. 

For the new generation of satellite communication systems, more users, more channels and higher bit rates are the inevitable development trend in the future, and multipactor is an important technical bottleneck limiting the development of high-power space microwave components to higher power capacity. Numerical electromagnetic calculations can track the electron trajectories and internal field interactions more accurately, and the change in the number of secondary electrons over time is used as a criterion for the multipactor breakdown threshold. This paper provides a more simplified two-dimensional calculation model, combined with the secondary electron emission model, which can be used for the rapid calculation of the weak links of microwave components, illustrated by the calculation of a parallel flat plate structure with a very narrow gap as an example, which takes into account the electron emission in the low-energy state, and some computational details are illustrated, and its prediction threshold is compared with other simulation methods, with an error of less than 2dB, which verifies the validity of the method.

Aiming at the Earth observation and imaging task of low-Earth-orbit optical satellite， the imaging probability distribution of the Earth surface target under the condition of satellite rolling attitude is studied. Firstly， the mathematical relationship between the imaging probability density function and the roll angle is analyzed analytically， and on this basis， the general formula of imaging probability in the roll angle range is given. Then， theoretical analysis and STK simulation analysis are carried out on the imaging probability of 15 combinations for five orbit altitude of 400km， 500km， 600km， 700km and 800km and three maximum roll angles of 30°， 45° and 60°. Finally， the theoretical results and simulation results are compared and analyzed. The results of data comparison show that the theoretical analysis formula has high accuracy with a relative error of no more than 2% in most cases. It can be used for rapid estimation of imaging probability， effectively reducing the workload of satellite multi-scheme comparison and analysis.

Stable operation of the electrolytic oxygen system is key to stable continuous oxygen supply inside human spacecraft， and the critical operation condition of the electrolytic system is the basis of safe and stable operation. The critical water flow rate and the critical operating current for the operation of a single cell of an electrolytic oxygen generating core and an electrolytic stack under microgravity conditions are investigated， and a water supply optimization scheme is proposed by improving the local structure of the electrolytic stack. Numerical simulations are carried out using fluid dynamics simulation software， and a gas-liquid mixed two-phase flow model is used to describe the flow process inside the electrolytic core. For both the electrolytic cell unit and the electrolytic stack， there is a limit water flow rate when the operating current is a constant. When the water flow rate is smaller than this critical value， a local water shortage phenomenon occurs inside the core. For a specific water flow rate， there is a critical operating current， and when the current is greater than the critical value， there is a local water shortage inside the core. The uniformity of the flow distribution of the multilayer core can be significantly improved by increasing the diameter of the water supply pipe. With the increase of the diameter， the ratio of the minimum water mass flux to the average mass flux increases linearly and the ratio of the maximum flow rate to the average flow rate decreases linearly. Typically， when the pipe diameter increases by 75%， the ratio of the minimum flow rate to the average flow rate increases by about 39% and the ratio of the maximum flow rate to the average flow rate decreases by about 30%. The uniformity of water distribution is better when the inlet and outlet are on the same side of the electrolysis stack， and the ratio of the maximum to the average water flow can be reduced by more than 30% with the same water flow rate. The research work can provide parameter suggestions for the safe operation of electrolysis tanks for human spacecraft and a basis for the optimal design of the system.

During the long time on-orbit operation of space cryogenic propellant tanks, the continuous evaporation of cryogenic propellant in the tanks due to heat leakage from the wall surface causes the pressure in the tanks to rise continuously (i. e. the self-pressurization phenomenon), jeopardizing the safety of the tanks and the spacecraft. In order to prevent large liquid sloshing, large-scale spatial tanks are equipped with sloshing-suppression barriers, which may have a significant impact on the gas-liquid flow and heat transfer inside the tank. In this paper, the effect of the near-wall barrier on the gas-liquid two-phase flow and its thermodynamic process in the storage tank is numerically simulated using the VOF method, in order to reveal the mechanism of the effect of the sloshing-suppression barrier on the self-pressurization process of the storage tank. Numerical simulation results of liquid sloshing and thermodynamic characteristics in partially liquid-filled storage tanks with and without near-wall barriers in different gravity environments show that: the liquid surface configuration in the tank is determined by the Bond number, and the liquid surface basically stays flat in the condition of Bond number much larger than 1, while the liquid surface climbs along the wall of the tank in the case of Bond number less than 1; near-wall sloshing-suppression barriers can significantly reduce the fluctuation of the center of mass of the fluid in the tank; when the near-wall sloshing-suppression barrier is located below the liquid surface, it can hinder the rise of liquid warming in the near-wall area, which makes the liquid surface temperature in the near-wall area low, and the self-pressurization rate is obviously lower than that of the storage tank without a barrier. Finally, based on the simulation analysis and comparison of the effect of the near-wall barrier size, the recommended configurations of the near-wall sloshing-suppression barriers under different gravity conditions are given. The results of the study can provide a valuable reference for the program design of fluid management technology for space tanks.

The capillary performance of porous structure is one of the main factors that determine whether the liquid propellant can be obtained stably in the storage tank under microgravity. The multilayer stainless porous array structure whose microcolumn distance ranges from 50μm to 110μm was prepared through 3D printing. The internal structure and surface morphology of the porous array structure are observed with the X-ray microscope and scanning electron microscope.The capillary rising process in the porous array structure is investigated with the infrared camera by using HFE7500， ethanol， and ethylene glycol as the working fluids. The capillary performance parameters are obtained through the capillary rising curves. The results show that the porosity of the porous array structure increases as the microcolumn distance increases. Besides， a larger microcolumn distance leads to a faster rising velocity and a larger rising height. The maximum rising height of a porous array structure with a microcolumn distance of 110μm is 2.34 times that of a porous array structure with a microcolumn distance of 50μm. For the same porous array structure， the rising velocity with the ethanol is the highest， followed by HFE7500 and ethylene glycol， respectively. Moreover， the capillary performance factor increases as the microcolumn distance increases， indicating that the porous array structure with a microcolumn distance of 110μm has the best comprehensive capillary performance. The results provide a reference for the design of porous structure liquid acquisition device.