The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures...The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures using camera sunshades to suppress the“Sun transit”and the issue of excessively large solar avoidance angles determined solely by geometric relationships,a thermal control design method is proposed that involves adding multi-layer thermal protection at the secondary mirror position of the camera.The goal is to optimize the avoidance angle and enhance the camera’s tolerance to“Sun transit”.A heat balance and motion relationship between the avoidance angle and duration is established.Then,the minimum solar avoidance angle after adopting the multi-layer thermal protection design is calculated.This angle is compared with the one determined by geometric relationships,leading to the conclusion that this method can effectively enhance the camera’s tolerance to“Sun transit”.A heat dissipation scheme is proposed that involves a coupled north-south heat spreader design with low-temperature compensation for the internal heat source.The calculation results of the two avoidance angles are applied to the calculation of the heat dissipation area and low-temperature compensation power,achieving a closed-loop heat dissipation scheme.Puls,the superiority of the multi-layer thermal protection design method is demonstrated from the perspectives of heat dissipation area and low-temperature compensation power requirements.A comparative analysis of simulation analysis,thermal balance tests,and in-orbit temperature data further validates the effectiveness of this method.展开更多
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
The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extract...The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic oxides.This oxygen and metal extraction can be achieved using existing metallurgical techniques.Furthermore,the ample reserves of water ice on the Moon offer another means for oxygen production.This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental conditions.It delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar regolith.The two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the Moon.Considering the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon.This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.展开更多
Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria i...Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.展开更多
Considering the special walking behavior of astronauts on the lunar surface,to reduce the impact on their bones and improve safety during extravehicular operations and walking,a magnetorheological(MR)damping mechanism...Considering the special walking behavior of astronauts on the lunar surface,to reduce the impact on their bones and improve safety during extravehicular operations and walking,a magnetorheological(MR)damping mechanism of power assisted transmission joint used in a new type spacesuit is proposed.In order to improve the damping performance of the MR damper,the influence of the damper s structural parameters on both the output and dynamic adjustable range of the damping torque is examined.According to the theoretical mechanical model,the output damping torque is calculated,the finite element method is used to conduct numerical tests.At the same time,the structural parameters of the damper are optimized by the response surface methods.The results indicate that the simulated torque aligns with the theoretically designed torque,and the damping characteristics of the optimized structure are effectively improved by the response surface method.Compared with the initial structure,the damping torque is increased by 10.8%,and the dynamic adjustable range is expanded by 52.9%.展开更多
吸声材料是火箭常用的降噪方法之一。针对高速火箭整流罩,采用三聚氰胺泡沫塑料吸声材料开展了被动控制内声场降噪方法的实验和数值研究。首先,建立了阻抗管的实验平台,实验测量了吸声材料在不同厚度和表面处理下的吸声系数。然后,基于...吸声材料是火箭常用的降噪方法之一。针对高速火箭整流罩,采用三聚氰胺泡沫塑料吸声材料开展了被动控制内声场降噪方法的实验和数值研究。首先,建立了阻抗管的实验平台,实验测量了吸声材料在不同厚度和表面处理下的吸声系数。然后,基于该材料设计了多种火箭整流罩的内声场降噪的方案,采用统计能量数值仿真方法及混响室噪声环境实验,研究了吸声材料厚度、表面处理及布局方式对整流罩降噪性能影响规律。结果表明,采用吸声材料能够有效降低整流罩内声场噪声,总声压级隔声量最大达5.5 d B,厚度增加和表面处理在一定程度上能够增加隔声量。展开更多
基金supported by the Na⁃tional Key Research and Development Program of China(No.2021YFC2202102)。
文摘The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures using camera sunshades to suppress the“Sun transit”and the issue of excessively large solar avoidance angles determined solely by geometric relationships,a thermal control design method is proposed that involves adding multi-layer thermal protection at the secondary mirror position of the camera.The goal is to optimize the avoidance angle and enhance the camera’s tolerance to“Sun transit”.A heat balance and motion relationship between the avoidance angle and duration is established.Then,the minimum solar avoidance angle after adopting the multi-layer thermal protection design is calculated.This angle is compared with the one determined by geometric relationships,leading to the conclusion that this method can effectively enhance the camera’s tolerance to“Sun transit”.A heat dissipation scheme is proposed that involves a coupled north-south heat spreader design with low-temperature compensation for the internal heat source.The calculation results of the two avoidance angles are applied to the calculation of the heat dissipation area and low-temperature compensation power,achieving a closed-loop heat dissipation scheme.Puls,the superiority of the multi-layer thermal protection design method is demonstrated from the perspectives of heat dissipation area and low-temperature compensation power requirements.A comparative analysis of simulation analysis,thermal balance tests,and in-orbit temperature data further validates the effectiveness of this method.
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financially supported by the National Natural Science Foundation of China(Nos.52404328,52274412,and 52374418)the China Postdoctoral Science Foundation(No.2024M753248)。
文摘The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic oxides.This oxygen and metal extraction can be achieved using existing metallurgical techniques.Furthermore,the ample reserves of water ice on the Moon offer another means for oxygen production.This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental conditions.It delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar regolith.The two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the Moon.Considering the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon.This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.
基金supported by the National Natural Science Foundation of China(Nos.51971032,52371048,and 52071019).
文摘Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.
基金The Natural Science Foundation of Shanghai(No.20ZR1401300).
文摘Considering the special walking behavior of astronauts on the lunar surface,to reduce the impact on their bones and improve safety during extravehicular operations and walking,a magnetorheological(MR)damping mechanism of power assisted transmission joint used in a new type spacesuit is proposed.In order to improve the damping performance of the MR damper,the influence of the damper s structural parameters on both the output and dynamic adjustable range of the damping torque is examined.According to the theoretical mechanical model,the output damping torque is calculated,the finite element method is used to conduct numerical tests.At the same time,the structural parameters of the damper are optimized by the response surface methods.The results indicate that the simulated torque aligns with the theoretically designed torque,and the damping characteristics of the optimized structure are effectively improved by the response surface method.Compared with the initial structure,the damping torque is increased by 10.8%,and the dynamic adjustable range is expanded by 52.9%.
文摘吸声材料是火箭常用的降噪方法之一。针对高速火箭整流罩,采用三聚氰胺泡沫塑料吸声材料开展了被动控制内声场降噪方法的实验和数值研究。首先,建立了阻抗管的实验平台,实验测量了吸声材料在不同厚度和表面处理下的吸声系数。然后,基于该材料设计了多种火箭整流罩的内声场降噪的方案,采用统计能量数值仿真方法及混响室噪声环境实验,研究了吸声材料厚度、表面处理及布局方式对整流罩降噪性能影响规律。结果表明,采用吸声材料能够有效降低整流罩内声场噪声,总声压级隔声量最大达5.5 d B,厚度增加和表面处理在一定程度上能够增加隔声量。
