With the development of space-based remote sensing and deep space exploration technology,higher standards for temperature stability and uniformity of payloads have been proposed to spacecraft thermal control systems.A...With the development of space-based remote sensing and deep space exploration technology,higher standards for temperature stability and uniformity of payloads have been proposed to spacecraft thermal control systems.As an efficient two-phase heat transfer device with active temperature control capabilities,the loop heat pipe(LHP)can be widely applied in spacecraft thermal control systems to achieve reliable temperature control under various operating modes and complex space thermal environments.This paper analyzes the fundamental theories of thermal switch-controlled,reservoir temperature-controlled,and bypass valve-controlled LHPs.The focus is on the theories and methods of achieving high-precision and high-reliability temperature control via active reservoir temperature control.Novel control techniques in recent years,such as non-condensable gas(NCG)control with a temperature stability of 0.01℃ ,are also briefly introduced as promising approaches to improve LHP performance.The on-orbit performance and characteristics of various LHP temperature control methods are provided and ranked in terms of control precision,energy consumption,complexity,and weight.Thermoelectric cooler(TEC)/electrical heater,as the foundation of reservoir temperature control,can achieve a temperature stability of in space applications under±0.2℃ a wide range of heat load.Microgravity model,control strategy,and operating mode conversion are three optimization directions that would hopefully further expand the application scenario of reservoir temperature control.Specific design principles and challenges for corresponding directions are summarized as guidance for researchers.展开更多
It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comp...It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comprehensive overview of advances in the development of bumper materials for spacecraft shield applications.In particular,the protective mechanism and process of the bumper using different materials against hypervelocity impact are reviewed and discussed.The advantages and disadvantages of each material used in shield were discussed,and the performance under hypervelocity impact was given according to the specific configuration.This review provides the useful reference and basis for researchers and engineers to create bumper materials for spacecraft shield applications,and the contemporary challenges and future directions for bumper materials for spacecraft shield were presented.展开更多
The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is litt...The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer （SMP）-inflation, and electrostatic form- ing. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials （including polyester film and polyimide film） for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different ten- sioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures,materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.展开更多
The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1,...The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1, 2, and 3 mm. First, the primary arc voltage characteristics of a solar array are analyzed. It is found that two steps are involved in the primary arc voltages, which are 116 and 22 V according to our experiment and are independent of the electrostatic discharge current and the gap lengths. By comparing with the arc pattern, we determined that current chopping may be the reason for the stepped arc voltage. Then, the characteristics of the secondary arc of the solar array are demonstrated. The study shows that the secondary arc voltage values increase with the gap length. In the case of the same cell with a fixed gap length, the voltage of the secondary arc increases with the string current. Finally, the relationship between the secondary arc voltage and the gap length is obtained which helps the string voltage and the gap length selection for system design.展开更多
Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous....Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous. To deal with this problem, an optimal maneuvering strategy based on the relative navigation observability degree is proposed with angles-only measurements. A maneuver evasion relative navigation model in the spacecraft’s orbital plane is constructed and the observability measurement criteria with process noise and measurement noise are defined based on the posterior Cramer-Rao lower bound. Further, the optimal maneuver evasion strategy in spacecraft’s orbital plane based on the observability is proposed. The strategy provides a new idea for spacecraft to evade safety threats autonomously. Compared with the spacecraft evasion problem based on the absolute navigation, more accurate evasion results can be obtained. The simulation indicates that this optimal strategy can weaken the system’s observability and reduce the state estimation accuracy of the non-cooperative target, making it impossible for the non-cooperative target to accurately approach the spacecraft.展开更多
A large number of pyroshock devices are employed in spacecraft and rockets to realize stage separation and appendage deployment.Release of pyroshock devices induces high-level transient shock responses which tend to c...A large number of pyroshock devices are employed in spacecraft and rockets to realize stage separation and appendage deployment.Release of pyroshock devices induces high-level transient shock responses which tend to cause fatal damages in electronic equipment made of crystals and brittle materials.This paper aims to provide methods to isolate pyroshock and guarantee the safety of such equipment against high-frequency shocks.Firstly,stress wave transmission mechanism in stepped rods is investigated,upon which optimal area rate for shock isolation is achieved.Then,two spacecraft-rocket interface structures for pyroshock isolation,namely isolation hole and interim segment,are proposed.Both numerical simulations and experiments are carried out to validate the two shock isolation strategies.It is revealed that the interim segment structure shows better pyroshock isolation performance at the cost of increasing the weight of launching system whereas isolation hole is an optimal choice to reduce pyroshock response without causing weight increase.展开更多
In the space plasma environment, primary discharge may occur on the solar array and evolve into a destructive sustained arc, which threatens the safe operation of the spacecraft. Based on the plasma expansion fluid th...In the space plasma environment, primary discharge may occur on the solar array and evolve into a destructive sustained arc, which threatens the safe operation of the spacecraft. Based on the plasma expansion fluid theory, a new multicomponent plasma expansion model is proposed in this study, which takes into account the effects of ion species, ion number, initial discharge current, and Low Earth Orbit(LEO) plasma environment. The expansion simulation of single-component and multicomponent ions is carried out respectively, and the variations of plasma number density, expansion distance, and speed during the expansion process are obtained.Compared with the experimental results, the evolution of propagation distance and speed is closed and the error is within a reasonable range, which verifies the validity and rationality of the model. The propagation characteristics of the primary discharge on the solar array surface and the influence of the initial value on the maximum propagation distance and the propagation current peaks are investigated. This study can provide important theoretical support for the propagation and evolution of the primary discharge and the key behavior of the transition to secondary discharge on spacecraft solar array.展开更多
The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of s...The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of systematic and comprehensive research on the shock environment of spacecraft electronic equipment due to the diversity and complexity of the shock environment.In this paper,the validity of the finite element model is verified based on the sinusoidal vibration experiment results of the spacecraft reentry capsule.The method of shock dynamic response analysis is used to obtain the shock environment of electronic equipment under different shock loads.The shock response spectrum is used to describe the shock environment of aerospace electronic equipment.The results show that the resonance frequency error between the sinusoidal vibration experiment and the model is less than 4.06%.When the docking relative speed of the reentry capsule is 2 m/s,the shock response spectrum values of one of the equipment are 30 m^(2)/s,0.67 m/s,and 0.059 m,respectively.The wire rope spring on the mating surface can provide vibration isolation and shock resistance.An increase in spring damping coefficient results in a decrease in the amplitude and time of the vibration generated.An increase in spring stiffness reduces the input of shock load within a certain range.These research results can provide guidance for the design and evaluation of shock environmental adaptability of aerospace electronic equipment.展开更多
In this work,we successfully fabricate an ultra-high strength Mg-11Gd-3Y-0.5Zr alloy with ultimate tensile strength of 523 MPa and enhanced ductility via cost-effective bi-directional forging (BDF) and subsequent anne...In this work,we successfully fabricate an ultra-high strength Mg-11Gd-3Y-0.5Zr alloy with ultimate tensile strength of 523 MPa and enhanced ductility via cost-effective bi-directional forging (BDF) and subsequent annealing heat treatments.To elucidate the role of BDF and gain a fundamental understanding of the remarkable simultaneous increase of strength and ductility,systematic microstructure characterization and analysis are performed.It is revealed that the double-peak basal texture,with basal poles located at the center of two mutually perpendicular forging directions,serves as an essential factor for the strength-ductility synergy of the Mg-11Gd-3Y-0.5Zr alloy processed with BDF.Roles of the double-peak basal texture in overcoming the strength-ductility trade-off include promoting non-basal slip,increasing ductility,and enlarging the Hall-Petch effect along the sample elongation direction while reducing the extent of anisotropy in critical resolved shear stresses of different slip systems.This study demonstrates that texture engineering is a powerful strategy to control magnesium alloy performance and BDF is a promising processing technique for enhancing mechanical properties of magnesium alloys.展开更多
As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of...As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.展开更多
The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importa...The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.展开更多
AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the...AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the interface was investigated.Moreover,the interface bonding mechanisms of the AZ31/Al/Ta composites during the VHCB process were explored.The results demonstrate that as the VHCB temperature increases,the phase composition of the interface between Mg and Al changes from the Mg-Al brittle intermetallic compounds(Al_(12)Mg_(17)and Al_(3)Mg_(2))to the Al-Mg solid solution.Meanwhile,the width of the Al/Ta interface diffusion layer at 450℃increases compared to that at 400℃.The shear strengths are 24 and 46 MPa at 400 and 450℃,respectively.The interfacial bonding mechanism of AZ31/Al/Ta composites involves the coexistence of diffusion and mechanical meshing.Avoiding the formation of brittle phases at the interface can significantly improve interfacial bonding strength.展开更多
1.Introduction As the planets closest to the outer edge of the solar system,Uranus and Neptune,namely that of ice giants,retained a significant amount of gas from the early stages of the solar system's formation.T...1.Introduction As the planets closest to the outer edge of the solar system,Uranus and Neptune,namely that of ice giants,retained a significant amount of gas from the early stages of the solar system's formation.This gas contains the physical conditions of the protostellar cloud and position information about planet formation,making ice giants important prototypes for studying both the solar system and exoplanets.展开更多
Achieving vibration isolation,lightweight design,and reusability under impact remains a critical challenge for thin-walled structures.When the goat skull is subjected to impact,both the outer wall of the sinus and the...Achieving vibration isolation,lightweight design,and reusability under impact remains a critical challenge for thin-walled structures.When the goat skull is subjected to impact,both the outer wall of the sinus and the internal bony struts deform simultaneously to absorb energy and protect intracranial tissues.Inspired by this mechanism,we designed the goat sinus-inspired bio mimetic(GSIB) structure by mimicking the outer wall of the sinus and the internal pillar-like support system.The structure consists of dual coupling beams,including a set of inclined cantilever beams representing the sinus outer wall and vertical support beams simulating the internal bony struts.The GSIB structure was fabricated using Selective Laser Sintering(SLS) 3D printing technology,and its mechanical properties were investigated through a combination of quasi-static compression tests,vibration tests,impact tests,and finite element simulations.Under compressive loading,the inclined cantilever beams buckle to introduce a negative stiffness effect,while the vertical supports enhance overall stiffness.Leveraging the coupling effect between these two components,the structure achieves a long-stroke constant-force response,thereby delivering superior performance in energy absorption and vibration isolation.Additionally,the special deformation mode of the GSIB structure enables it to be reused under impact conditions.It is noteworthy that,compared to the negative stiffness(NS) structure with the same dimensions for repeated buffering proposed in previous studies,the GSIB structure demonstrates an energy absorption capacity reaching 214.3% of that of the NS structure,a reduction in isolation frequency to 58.5%,and an impact acceleration that is only 66.31% of that of the NS structure.Additionally,the plateau stress of the proposed structure increases to 246.07% of that of the NS structure.This novel artificial structure provides a new design strategy for achieving superior energy absorption and impact resistance under repeated impact conditions.展开更多
As space activities become increasingly central to global technological and strategic agendas,developing countries are expressing growing interest in acquiring indigenous space capabilities.However,traditional models ...As space activities become increasingly central to global technological and strategic agendas,developing countries are expressing growing interest in acquiring indigenous space capabilities.However,traditional models of international space cooperation-such as satellite exports and technical joint ventures-often fail to align with the resource constraints and capacity needs of these nations.In response,spacefaring countries like Japan and India have implemented innovative,small-scale capacity-building initiatives that offer training,satellite design experience,and in-orbit deployment opportunities to emerging space actors.This study systematically examines these representative programs,identifies their defining characteristics-including cost-efficiency,full financial support,and strong international legitimacy-and assesses their broader diplomatic and strategic impact.Building on this empirical foundation,the study argues for the strategic relevance of space capacity-building as a potential new model of China’s international space cooperation.Through a tripartite analytical framework of rationale,necessity,and feasibility,the study demonstrates that China possesses both the infrastructural foundation and imperative to adopt this model.It further proposes actionable recommendations to institutionalize capacity-building programs,integrate them into flagship national space missions,and align them with China’s broader foreign policy visions.Ultimately,space capacity-building cooperation is positioned as a low-risk,high-impact approach to fostering trust,expanding influence,and promoting global space governance.展开更多
As the Mars probe,which has limited on-board ability in computation is unable to carry out the large-scale landmark solution,it is necessary to achieve optimal selection of landmarks while ensuring autonomous navigati...As the Mars probe,which has limited on-board ability in computation is unable to carry out the large-scale landmark solution,it is necessary to achieve optimal selection of landmarks while ensuring autonomous navigation accuracy during landing phase.This paper proposes an optimal landmark selection method based on the observability matrix for the Mars probe.Firstly,an observability matrix for navigation system is constructed with Fisher information quantity.Secondly,the optimal configuration of the landmark distribution is given by maximizing the scalar function of the observability matrix.Based on the optimal configuration,the greedy algorithm is used to determine the number of the landmarks at each moment adaptively.In addition,considering the fact that the number of the observable landmarks gradually decreases during the landing process,the convergence threshold of the greedy algorithm is set to a dynamic value regarding landing time.Finally,mathematical simulation verification is conducted,and the results show that the proposed optimal landmark selection method has higher navigation accuracy compared with the random landmark selection method.It can effectively suppress the influence of the measurement model errors and achieve a higher landing accuracy.展开更多
The loop heat pipe with a flat evaporator is mainly divided into two forms:rectangular evaporator and disk-shaped evaporator.The rectangular evaporator has advantages such as low heat leakage,a thin shell,and a large ...The loop heat pipe with a flat evaporator is mainly divided into two forms:rectangular evaporator and disk-shaped evaporator.The rectangular evaporator has advantages such as low heat leakage,a thin shell,and a large contact area compared to the disk-shaped evaporator.However,most of the research on rectangular evaporators focuses onworking fluids such as water,methanol,and acetone,when theseworking fluids are in operation,the internal pressure of the evaporator is less than atmospheric pressure.Ammonia,propylene,and other working fluids can also be utilized in the loop heat pipe,these working fluids demonstrate better performance when operating within other temperature intervals,for example,the operating temperature range of ammonia is−20℃to 50℃,however,in an atmospheric pressure environment,it is very difficult for the shell of the rectangular evaporator to withstand the saturated vapor pressure of the working fluid.This paper designs a rectangular flat plate loop heat pipe that can use ammonia as the working fluid.The internal reinforcing structure is used to improve the pressure strength of the shell.The secondary wick connects the compensation chamber and the capillary wick hydraulically.The experiment indicates that this kind of rectangular evaporator is unaffected by the position,and the secondary wick can effectively supply liquid under different angles.The thermal resistance of the evaporator wall was analyzed,and it was found that the thermal resistance of the evaporator wall was the main component of the thermal resistance of the system.The heat transfer capacities of 460 W@0.5 m and 200W@10 m were tested.The test results indicate that by setting a reinforcing structure inside the flat plate evaporator,the evaporator can withstand internal pressure.Combined with the design of the secondary wick,the flat plate evaporator can use working fluids with different pressures,expanding the range of available working fluids.展开更多
With the increasing accuracy requirements of satellite magnetic detection missions,reducing low-frequency noise has become a key focus of satellite magnetic cleanliness technology.Traditional satellite magnetic simula...With the increasing accuracy requirements of satellite magnetic detection missions,reducing low-frequency noise has become a key focus of satellite magnetic cleanliness technology.Traditional satellite magnetic simulation methods have matured in static magnetic dipole simulations,but there is still significant room for optimization in the simulation and computation of low-frequency magnetic dipole models.This study employs the Gauss-Newton method and Fourier transform techniques for modeling and simulating low-frequency magnetic dipoles.Compared to the traditional particle swarm optimization(PSO)algorithm,this method achieves significant improvements,with errors reaching the order of10^(-13)%under noise-free conditions and maintaining an error level of less than 0.5%under 10%noise.Additionally,the use of Fourier transform and the Gauss-Newton method enables high-precision magnetic field frequency identification and rapid computation of the dipole position and magnetic moment,greatly enhancing the computational efficiency and accuracy of the model.展开更多
Vision-based relative pose estimation plays a pivotal role in various space missions.Deep learning enhances monocular spacecraft pose estimation,but high computational demands necessitate model simplification for onbo...Vision-based relative pose estimation plays a pivotal role in various space missions.Deep learning enhances monocular spacecraft pose estimation,but high computational demands necessitate model simplification for onboard systems.In this paper,we aim to achieve an optimal balance between accuracy and computational efficiency.We present a Perspective-n-Point(PnP)based method for spacecraft pose estimation,leveraging lightweight neural networks to localize semantic keypoints and reduce computational load.Since the accuracy of keypoint localization is closely related to the heatmap resolution,we devise an efficient upsampling module to increase the resolution of heatmaps with minimal overhead.Furthermore,the heatmaps predicted by the lightweight models tend to show high-level noise.To tackle this issue,we propose a weighting strategy by analyzing the statistical characteristics of predicted semantic keypoints and substantially improve the pose estimation accuracy.The experiments carried out on the SPEED dataset underscore the prospect of our method in engineering applications.We dramatically reduce the model parameters to 0.7 M,merely 2.5%of that required by the top-performing method,and achieve lower pose estimation error and better real-time performance.展开更多
Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a t...Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a three-impulse contingency return trajectory scheme is presented by combining the Lambert transfer and maneuver at the special point.Secondly,a calculation model of three-impulse contingency return trajectories is established.Then,fast calculation methods are proposed by adopting the high-order Taylor expansion of differential algebra in the twobody trajectory dynamics model and perturbed trajectory dynamics model.Finally,the performance of the proposed methods is verified by numerical simulation.The results indicate that the fast calculation method of two-body trajectory has higher calculation efficiency compared to the semi-analytical calculation method under a certain accuracy condition.Due to its high efficiency,the characteristics of the three-impulse contingency return trajectories under different contingency scenarios are further analyzed expeditiously.These findings can be used for the design of contingency return trajectories in future manned lunar landing missions.展开更多
基金funded by National Outstanding Youth Foundation of China,grant number 2020-JCJQ-ZQ-042.
文摘With the development of space-based remote sensing and deep space exploration technology,higher standards for temperature stability and uniformity of payloads have been proposed to spacecraft thermal control systems.As an efficient two-phase heat transfer device with active temperature control capabilities,the loop heat pipe(LHP)can be widely applied in spacecraft thermal control systems to achieve reliable temperature control under various operating modes and complex space thermal environments.This paper analyzes the fundamental theories of thermal switch-controlled,reservoir temperature-controlled,and bypass valve-controlled LHPs.The focus is on the theories and methods of achieving high-precision and high-reliability temperature control via active reservoir temperature control.Novel control techniques in recent years,such as non-condensable gas(NCG)control with a temperature stability of 0.01℃ ,are also briefly introduced as promising approaches to improve LHP performance.The on-orbit performance and characteristics of various LHP temperature control methods are provided and ranked in terms of control precision,energy consumption,complexity,and weight.Thermoelectric cooler(TEC)/electrical heater,as the foundation of reservoir temperature control,can achieve a temperature stability of in space applications under±0.2℃ a wide range of heat load.Microgravity model,control strategy,and operating mode conversion are three optimization directions that would hopefully further expand the application scenario of reservoir temperature control.Specific design principles and challenges for corresponding directions are summarized as guidance for researchers.
基金supported by National Natural Science Foundation of China(Grant Nos.12202068,12202087)China National Space Administration Preliminary Research Project(Grant Nos.KJSP2023020201,KJSP2020010402).
文摘It is widely known that the hypervelocity impact of orbital debris can cause serious damage to spacecraft,and enhancing the impact resistance is the great concern of spacecraft shield design.This paper provides a comprehensive overview of advances in the development of bumper materials for spacecraft shield applications.In particular,the protective mechanism and process of the bumper using different materials against hypervelocity impact are reviewed and discussed.The advantages and disadvantages of each material used in shield were discussed,and the performance under hypervelocity impact was given according to the specific configuration.This review provides the useful reference and basis for researchers and engineers to create bumper materials for spacecraft shield applications,and the contemporary challenges and future directions for bumper materials for spacecraft shield were presented.
基金Supported by Research Fund of Institute of Spacecraft System Engineering,China Academy of Space Technology,China(Grant No.ZTBYY-7)
文摘The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer （SMP）-inflation, and electrostatic form- ing. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials （including polyester film and polyimide film） for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different ten- sioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures,materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.
基金supported by National Natural Science Foundation of China (No. 51407008)
文摘The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1, 2, and 3 mm. First, the primary arc voltage characteristics of a solar array are analyzed. It is found that two steps are involved in the primary arc voltages, which are 116 and 22 V according to our experiment and are independent of the electrostatic discharge current and the gap lengths. By comparing with the arc pattern, we determined that current chopping may be the reason for the stepped arc voltage. Then, the characteristics of the secondary arc of the solar array are demonstrated. The study shows that the secondary arc voltage values increase with the gap length. In the case of the same cell with a fixed gap length, the voltage of the secondary arc increases with the string current. Finally, the relationship between the secondary arc voltage and the gap length is obtained which helps the string voltage and the gap length selection for system design.
基金supported by the National Key R&D Program of China (2020YFA0713502)the Special Fund Project for Guiding Local Scientific and Technological Development (2020ZYT003)+1 种基金the National Natural Science Foundation of China (U20B2055,61773021,61903086)the Natural Science Foundation of Hunan Province (2019JJ20018,2020JJ4280)。
文摘Spacecraft orbit evasion is an effective method to ensure space safety. In the spacecraft’s orbital plane, the space non-cooperate target with autonomous approaching to the spacecraft may have a dangerous rendezvous. To deal with this problem, an optimal maneuvering strategy based on the relative navigation observability degree is proposed with angles-only measurements. A maneuver evasion relative navigation model in the spacecraft’s orbital plane is constructed and the observability measurement criteria with process noise and measurement noise are defined based on the posterior Cramer-Rao lower bound. Further, the optimal maneuver evasion strategy in spacecraft’s orbital plane based on the observability is proposed. The strategy provides a new idea for spacecraft to evade safety threats autonomously. Compared with the spacecraft evasion problem based on the absolute navigation, more accurate evasion results can be obtained. The simulation indicates that this optimal strategy can weaken the system’s observability and reduce the state estimation accuracy of the non-cooperative target, making it impossible for the non-cooperative target to accurately approach the spacecraft.
基金supports from National Natural Science Foundation of China(No.11902286 and 11972204)。
文摘A large number of pyroshock devices are employed in spacecraft and rockets to realize stage separation and appendage deployment.Release of pyroshock devices induces high-level transient shock responses which tend to cause fatal damages in electronic equipment made of crystals and brittle materials.This paper aims to provide methods to isolate pyroshock and guarantee the safety of such equipment against high-frequency shocks.Firstly,stress wave transmission mechanism in stepped rods is investigated,upon which optimal area rate for shock isolation is achieved.Then,two spacecraft-rocket interface structures for pyroshock isolation,namely isolation hole and interim segment,are proposed.Both numerical simulations and experiments are carried out to validate the two shock isolation strategies.It is revealed that the interim segment structure shows better pyroshock isolation performance at the cost of increasing the weight of launching system whereas isolation hole is an optimal choice to reduce pyroshock response without causing weight increase.
基金supported by National Natural Science Foundation of China (Nos. 51937004 and 51977002)sponsored by Beijing Nova Program (No. 20220484153)。
文摘In the space plasma environment, primary discharge may occur on the solar array and evolve into a destructive sustained arc, which threatens the safe operation of the spacecraft. Based on the plasma expansion fluid theory, a new multicomponent plasma expansion model is proposed in this study, which takes into account the effects of ion species, ion number, initial discharge current, and Low Earth Orbit(LEO) plasma environment. The expansion simulation of single-component and multicomponent ions is carried out respectively, and the variations of plasma number density, expansion distance, and speed during the expansion process are obtained.Compared with the experimental results, the evolution of propagation distance and speed is closed and the error is within a reasonable range, which verifies the validity and rationality of the model. The propagation characteristics of the primary discharge on the solar array surface and the influence of the initial value on the maximum propagation distance and the propagation current peaks are investigated. This study can provide important theoretical support for the propagation and evolution of the primary discharge and the key behavior of the transition to secondary discharge on spacecraft solar array.
文摘The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents.There is currently a lack of systematic and comprehensive research on the shock environment of spacecraft electronic equipment due to the diversity and complexity of the shock environment.In this paper,the validity of the finite element model is verified based on the sinusoidal vibration experiment results of the spacecraft reentry capsule.The method of shock dynamic response analysis is used to obtain the shock environment of electronic equipment under different shock loads.The shock response spectrum is used to describe the shock environment of aerospace electronic equipment.The results show that the resonance frequency error between the sinusoidal vibration experiment and the model is less than 4.06%.When the docking relative speed of the reentry capsule is 2 m/s,the shock response spectrum values of one of the equipment are 30 m^(2)/s,0.67 m/s,and 0.059 m,respectively.The wire rope spring on the mating surface can provide vibration isolation and shock resistance.An increase in spring damping coefficient results in a decrease in the amplitude and time of the vibration generated.An increase in spring stiffness reduces the input of shock load within a certain range.These research results can provide guidance for the design and evaluation of shock environmental adaptability of aerospace electronic equipment.
基金National Natural Science Foundation of China (11988102 and 52301146)Chinese Postdoctoral Science Foundation (8206300226)+1 种基金National Science and Technology Infrastructure Platform Development Plan-Young Backbone Talents Training Project (52001325)Fundamental Research Funds for the Central Universities (JB2023118)。
文摘In this work,we successfully fabricate an ultra-high strength Mg-11Gd-3Y-0.5Zr alloy with ultimate tensile strength of 523 MPa and enhanced ductility via cost-effective bi-directional forging (BDF) and subsequent annealing heat treatments.To elucidate the role of BDF and gain a fundamental understanding of the remarkable simultaneous increase of strength and ductility,systematic microstructure characterization and analysis are performed.It is revealed that the double-peak basal texture,with basal poles located at the center of two mutually perpendicular forging directions,serves as an essential factor for the strength-ductility synergy of the Mg-11Gd-3Y-0.5Zr alloy processed with BDF.Roles of the double-peak basal texture in overcoming the strength-ductility trade-off include promoting non-basal slip,increasing ductility,and enlarging the Hall-Petch effect along the sample elongation direction while reducing the extent of anisotropy in critical resolved shear stresses of different slip systems.This study demonstrates that texture engineering is a powerful strategy to control magnesium alloy performance and BDF is a promising processing technique for enhancing mechanical properties of magnesium alloys.
文摘As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.
文摘The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.
基金National Natural Science Foundation of China(52275308,52301146)Fundamental Research Funds for the Central Universities(2023JG007)Supported by Shi Changxu Innovation Center for Advanced Materials(SCXKFJJ202207)。
文摘AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the interface was investigated.Moreover,the interface bonding mechanisms of the AZ31/Al/Ta composites during the VHCB process were explored.The results demonstrate that as the VHCB temperature increases,the phase composition of the interface between Mg and Al changes from the Mg-Al brittle intermetallic compounds(Al_(12)Mg_(17)and Al_(3)Mg_(2))to the Al-Mg solid solution.Meanwhile,the width of the Al/Ta interface diffusion layer at 450℃increases compared to that at 400℃.The shear strengths are 24 and 46 MPa at 400 and 450℃,respectively.The interfacial bonding mechanism of AZ31/Al/Ta composites involves the coexistence of diffusion and mechanical meshing.Avoiding the formation of brittle phases at the interface can significantly improve interfacial bonding strength.
文摘1.Introduction As the planets closest to the outer edge of the solar system,Uranus and Neptune,namely that of ice giants,retained a significant amount of gas from the early stages of the solar system's formation.This gas contains the physical conditions of the protostellar cloud and position information about planet formation,making ice giants important prototypes for studying both the solar system and exoplanets.
文摘Achieving vibration isolation,lightweight design,and reusability under impact remains a critical challenge for thin-walled structures.When the goat skull is subjected to impact,both the outer wall of the sinus and the internal bony struts deform simultaneously to absorb energy and protect intracranial tissues.Inspired by this mechanism,we designed the goat sinus-inspired bio mimetic(GSIB) structure by mimicking the outer wall of the sinus and the internal pillar-like support system.The structure consists of dual coupling beams,including a set of inclined cantilever beams representing the sinus outer wall and vertical support beams simulating the internal bony struts.The GSIB structure was fabricated using Selective Laser Sintering(SLS) 3D printing technology,and its mechanical properties were investigated through a combination of quasi-static compression tests,vibration tests,impact tests,and finite element simulations.Under compressive loading,the inclined cantilever beams buckle to introduce a negative stiffness effect,while the vertical supports enhance overall stiffness.Leveraging the coupling effect between these two components,the structure achieves a long-stroke constant-force response,thereby delivering superior performance in energy absorption and vibration isolation.Additionally,the special deformation mode of the GSIB structure enables it to be reused under impact conditions.It is noteworthy that,compared to the negative stiffness(NS) structure with the same dimensions for repeated buffering proposed in previous studies,the GSIB structure demonstrates an energy absorption capacity reaching 214.3% of that of the NS structure,a reduction in isolation frequency to 58.5%,and an impact acceleration that is only 66.31% of that of the NS structure.Additionally,the plateau stress of the proposed structure increases to 246.07% of that of the NS structure.This novel artificial structure provides a new design strategy for achieving superior energy absorption and impact resistance under repeated impact conditions.
文摘As space activities become increasingly central to global technological and strategic agendas,developing countries are expressing growing interest in acquiring indigenous space capabilities.However,traditional models of international space cooperation-such as satellite exports and technical joint ventures-often fail to align with the resource constraints and capacity needs of these nations.In response,spacefaring countries like Japan and India have implemented innovative,small-scale capacity-building initiatives that offer training,satellite design experience,and in-orbit deployment opportunities to emerging space actors.This study systematically examines these representative programs,identifies their defining characteristics-including cost-efficiency,full financial support,and strong international legitimacy-and assesses their broader diplomatic and strategic impact.Building on this empirical foundation,the study argues for the strategic relevance of space capacity-building as a potential new model of China’s international space cooperation.Through a tripartite analytical framework of rationale,necessity,and feasibility,the study demonstrates that China possesses both the infrastructural foundation and imperative to adopt this model.It further proposes actionable recommendations to institutionalize capacity-building programs,integrate them into flagship national space missions,and align them with China’s broader foreign policy visions.Ultimately,space capacity-building cooperation is positioned as a low-risk,high-impact approach to fostering trust,expanding influence,and promoting global space governance.
基金supported by the National Natural Science Foundation of China(62203458)the Stabilisation Support Project of the Bureau of Science and Industry(HTKJ2023KL502012)the Youth Autonomous Innovation Science Fund(ZK23-01).
文摘As the Mars probe,which has limited on-board ability in computation is unable to carry out the large-scale landmark solution,it is necessary to achieve optimal selection of landmarks while ensuring autonomous navigation accuracy during landing phase.This paper proposes an optimal landmark selection method based on the observability matrix for the Mars probe.Firstly,an observability matrix for navigation system is constructed with Fisher information quantity.Secondly,the optimal configuration of the landmark distribution is given by maximizing the scalar function of the observability matrix.Based on the optimal configuration,the greedy algorithm is used to determine the number of the landmarks at each moment adaptively.In addition,considering the fact that the number of the observable landmarks gradually decreases during the landing process,the convergence threshold of the greedy algorithm is set to a dynamic value regarding landing time.Finally,mathematical simulation verification is conducted,and the results show that the proposed optimal landmark selection method has higher navigation accuracy compared with the random landmark selection method.It can effectively suppress the influence of the measurement model errors and achieve a higher landing accuracy.
基金Science Foundation for Distinguished Young Scholars 2020-JCJQ-ZQ-042.
文摘The loop heat pipe with a flat evaporator is mainly divided into two forms:rectangular evaporator and disk-shaped evaporator.The rectangular evaporator has advantages such as low heat leakage,a thin shell,and a large contact area compared to the disk-shaped evaporator.However,most of the research on rectangular evaporators focuses onworking fluids such as water,methanol,and acetone,when theseworking fluids are in operation,the internal pressure of the evaporator is less than atmospheric pressure.Ammonia,propylene,and other working fluids can also be utilized in the loop heat pipe,these working fluids demonstrate better performance when operating within other temperature intervals,for example,the operating temperature range of ammonia is−20℃to 50℃,however,in an atmospheric pressure environment,it is very difficult for the shell of the rectangular evaporator to withstand the saturated vapor pressure of the working fluid.This paper designs a rectangular flat plate loop heat pipe that can use ammonia as the working fluid.The internal reinforcing structure is used to improve the pressure strength of the shell.The secondary wick connects the compensation chamber and the capillary wick hydraulically.The experiment indicates that this kind of rectangular evaporator is unaffected by the position,and the secondary wick can effectively supply liquid under different angles.The thermal resistance of the evaporator wall was analyzed,and it was found that the thermal resistance of the evaporator wall was the main component of the thermal resistance of the system.The heat transfer capacities of 460 W@0.5 m and 200W@10 m were tested.The test results indicate that by setting a reinforcing structure inside the flat plate evaporator,the evaporator can withstand internal pressure.Combined with the design of the secondary wick,the flat plate evaporator can use working fluids with different pressures,expanding the range of available working fluids.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC2206003)。
文摘With the increasing accuracy requirements of satellite magnetic detection missions,reducing low-frequency noise has become a key focus of satellite magnetic cleanliness technology.Traditional satellite magnetic simulation methods have matured in static magnetic dipole simulations,but there is still significant room for optimization in the simulation and computation of low-frequency magnetic dipole models.This study employs the Gauss-Newton method and Fourier transform techniques for modeling and simulating low-frequency magnetic dipoles.Compared to the traditional particle swarm optimization(PSO)algorithm,this method achieves significant improvements,with errors reaching the order of10^(-13)%under noise-free conditions and maintaining an error level of less than 0.5%under 10%noise.Additionally,the use of Fourier transform and the Gauss-Newton method enables high-precision magnetic field frequency identification and rapid computation of the dipole position and magnetic moment,greatly enhancing the computational efficiency and accuracy of the model.
基金co-supported by the National Natural Science Foundation of China(Nos.12302252 and 12472189)the Research Program of National University of Defense Technology,China(No.ZK24-31).
文摘Vision-based relative pose estimation plays a pivotal role in various space missions.Deep learning enhances monocular spacecraft pose estimation,but high computational demands necessitate model simplification for onboard systems.In this paper,we aim to achieve an optimal balance between accuracy and computational efficiency.We present a Perspective-n-Point(PnP)based method for spacecraft pose estimation,leveraging lightweight neural networks to localize semantic keypoints and reduce computational load.Since the accuracy of keypoint localization is closely related to the heatmap resolution,we devise an efficient upsampling module to increase the resolution of heatmaps with minimal overhead.Furthermore,the heatmaps predicted by the lightweight models tend to show high-level noise.To tackle this issue,we propose a weighting strategy by analyzing the statistical characteristics of predicted semantic keypoints and substantially improve the pose estimation accuracy.The experiments carried out on the SPEED dataset underscore the prospect of our method in engineering applications.We dramatically reduce the model parameters to 0.7 M,merely 2.5%of that required by the top-performing method,and achieve lower pose estimation error and better real-time performance.
基金co-supported by the National Natural Science Foundation of China(No.12072365)the Technology Innovation Team of Manned Space Engineering,China。
文摘Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a three-impulse contingency return trajectory scheme is presented by combining the Lambert transfer and maneuver at the special point.Secondly,a calculation model of three-impulse contingency return trajectories is established.Then,fast calculation methods are proposed by adopting the high-order Taylor expansion of differential algebra in the twobody trajectory dynamics model and perturbed trajectory dynamics model.Finally,the performance of the proposed methods is verified by numerical simulation.The results indicate that the fast calculation method of two-body trajectory has higher calculation efficiency compared to the semi-analytical calculation method under a certain accuracy condition.Due to its high efficiency,the characteristics of the three-impulse contingency return trajectories under different contingency scenarios are further analyzed expeditiously.These findings can be used for the design of contingency return trajectories in future manned lunar landing missions.
