Pub Date : 2026-04-01Epub Date: 2025-12-27DOI: 10.1016/j.actaastro.2025.12.048
Jie Yang, Zhengtao Wei, Caoqun Luo, Ti Chen, Dongping Jin
Tethered satellite systems exhibit significant challenges during the trajectory planning of deployment and retrieval tasks because of their nonlinearity and under-actuation. This paper investigates the optimal planning of deployment and retrieval trajectories and the optimal design for some system parameters simultaneously considering external disturbances and the system’s nonlinear behaviors. Based on the dumbbell model of the tethered satellite system, a dynamics co-design framework is proposed to optimize trajectory and system parameters in deployment and retrieval tasks. To improve the robustness of the designed trajectory and parameters, two disturbance-rejection performance indices are included in the cost function of the optimal problem for the dynamics co-design task. The Legendre–Gauss–Radau pseudospectral method is employed to transform the continuous dynamics co-design problem into a large-scale nonlinear programming problem. To further improve efficiency, an hp-adaptive strategy is employed to refine the discretization mesh. Finally, the effectiveness of the dynamics co-design framework and the robust performance are validated by numerical simulations and ground experiments.
{"title":"Dynamics co-design for robust deployment and retrieval of tethered satellite systems","authors":"Jie Yang, Zhengtao Wei, Caoqun Luo, Ti Chen, Dongping Jin","doi":"10.1016/j.actaastro.2025.12.048","DOIUrl":"10.1016/j.actaastro.2025.12.048","url":null,"abstract":"<div><div>Tethered satellite systems exhibit significant challenges during the trajectory planning of deployment and retrieval tasks because of their nonlinearity and under-actuation. This paper investigates the optimal planning of deployment and retrieval trajectories and the optimal design for some system parameters simultaneously considering external disturbances and the system’s nonlinear behaviors. Based on the dumbbell model of the tethered satellite system, a dynamics co-design framework is proposed to optimize trajectory and system parameters in deployment and retrieval tasks. To improve the robustness of the designed trajectory and parameters, two disturbance-rejection performance indices are included in the cost function of the optimal problem for the dynamics co-design task. The Legendre–Gauss–Radau pseudospectral method is employed to transform the continuous dynamics co-design problem into a large-scale nonlinear programming problem. To further improve efficiency, an <em>hp</em>-adaptive strategy is employed to refine the discretization mesh. Finally, the effectiveness of the dynamics co-design framework and the robust performance are validated by numerical simulations and ground experiments.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 207-223"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2025-12-26DOI: 10.1016/j.actaastro.2025.12.050
Takahiro Ukai , Shin Hotta , Andrew Wilson , Bradley Craig , Craig White , Konstantinos Kontis , Yuki Takarada
We propose an active flow control technique using fluidic injectors to manipulate plume structures in plume surface interaction (PSI) phenomena during soft landing on planetary surfaces. While fluidic injectors are mainly proposed for noise reduction in aircraft engines, this study focuses on their application under planetary environments to modulate plumes extended by high nozzle pressure ratios. To investigate the performance of this proposed jet-jet interaction technique, which transverse supersonic jets penetrate a main hypersonic jet, we conduct both numerical simulations and experiments using four Mach 2.5 injector nozzles arranged around a Mach 5.8 main nozzle, under Martian ambient surface pressure. The jet-jet interaction reduces a Mach number of an impinging main jet on a perpendicular plate and expands its jet radius. These effects depend on the mass flow rate ratio between the main jet and the injector. Due to the reduced shock cell length, the highest mass flow rate ratio significantly decreases the stagnation pressure at the jet impingement centreline on the plate by approximately 90 % compared to the case without jet-jet interaction, whereas a pressure rise occurs in the radial direction due to jet expansion. These pressure changes may still alter regolith erosion. Furthermore, a wall shear stress associated with erosion dynamics is reduced by the jet-jet interaction. Although we successfully demonstrate the effectiveness of the jet-jet interaction using fluidic injectors for plume modulation under Martian ambient pressure, further investigations of the jet impingement on a soil bed are required to clarify the effects of this technique on erosion dynamics.
{"title":"A flow control technique for the manipulation of plume structures in plume-surface interaction","authors":"Takahiro Ukai , Shin Hotta , Andrew Wilson , Bradley Craig , Craig White , Konstantinos Kontis , Yuki Takarada","doi":"10.1016/j.actaastro.2025.12.050","DOIUrl":"10.1016/j.actaastro.2025.12.050","url":null,"abstract":"<div><div>We propose an active flow control technique using fluidic injectors to manipulate plume structures in plume surface interaction (PSI) phenomena during soft landing on planetary surfaces. While fluidic injectors are mainly proposed for noise reduction in aircraft engines, this study focuses on their application under planetary environments to modulate plumes extended by high nozzle pressure ratios. To investigate the performance of this proposed jet-jet interaction technique, which transverse supersonic jets penetrate a main hypersonic jet, we conduct both numerical simulations and experiments using four Mach 2.5 injector nozzles arranged around a Mach 5.8 main nozzle, under Martian ambient surface pressure. The jet-jet interaction reduces a Mach number of an impinging main jet on a perpendicular plate and expands its jet radius. These effects depend on the mass flow rate ratio between the main jet and the injector. Due to the reduced shock cell length, the highest mass flow rate ratio significantly decreases the stagnation pressure at the jet impingement centreline on the plate by approximately 90 % compared to the case without jet-jet interaction, whereas a pressure rise occurs in the radial direction due to jet expansion. These pressure changes may still alter regolith erosion. Furthermore, a wall shear stress associated with erosion dynamics is reduced by the jet-jet interaction. Although we successfully demonstrate the effectiveness of the jet-jet interaction using fluidic injectors for plume modulation under Martian ambient pressure, further investigations of the jet impingement on a soil bed are required to clarify the effects of this technique on erosion dynamics.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 114-133"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-07DOI: 10.1016/j.actaastro.2026.01.009
Zhan Wen , Yanfeng Jiang , Huisi Wang , Weichen Qu , Jiawei Yan , Peijin Liu , Wen Ao
This work utilized a technique known as single-particle laser ignition, paired with high-speed photography, spectrum to explore the ignition and combustion properties under −60 °C. The results indicate that while a decrease in temperature does not significantly alter the overall combustion processes—comprising melting expansion, rupture of the oxide film, stable combustion, and eventual extinction—it does diminish the intensity of the reactions occurring during ignition. When the temperature decreases, the ignition delay time for particles of the same size tends to increase, directly correlating with particle size. For instance, at −60 °C compared to 20 °C, Al particles with a diameter of 1000 μm show a notable rise in ignition delay time from 674 ms to 1098 ms, indicating a 62.9 % increase. In contrast, smaller Al particles are less sensitive to temperature changes. For 500 μm Al particles, the time it takes for ignition to occur increases from 163 ms to 218 ms as the temperature changes within the same range, resulting in a smaller percentage increase of 33.7 %. To better understand the ignition process, a model was created that accounts for the effects of both particle size and temperature on ignition behaviour. In the early stages of ignition, the main source of heat is convective heat transfer, which plays a crucial role in initiating the ignition process. Once the Al particles have melted completely, surface chemical reactions become a significant source of heat. This model accurately describes the influence of the initial temperature on the ignition process and energy transfer, showing an average deviation of 7.03 % between predicted ignition delay times for different temperatures and particle sizes compared to experimental data. Overall, this study enhances our understanding of the ignition and combustion processes of Al particles across a range of temperatures.
{"title":"Investigation of aluminum ignition dynamics with lower initial particle temperature","authors":"Zhan Wen , Yanfeng Jiang , Huisi Wang , Weichen Qu , Jiawei Yan , Peijin Liu , Wen Ao","doi":"10.1016/j.actaastro.2026.01.009","DOIUrl":"10.1016/j.actaastro.2026.01.009","url":null,"abstract":"<div><div>This work utilized a technique known as single-particle laser ignition, paired with high-speed photography, spectrum to explore the ignition and combustion properties under −60 °C. The results indicate that while a decrease in temperature does not significantly alter the overall combustion processes—comprising melting expansion, rupture of the oxide film, stable combustion, and eventual extinction—it does diminish the intensity of the reactions occurring during ignition. When the temperature decreases, the ignition delay time for particles of the same size tends to increase, directly correlating with particle size. For instance, at −60 °C compared to 20 °C, Al particles with a diameter of 1000 μm show a notable rise in ignition delay time from 674 ms to 1098 ms, indicating a 62.9 % increase. In contrast, smaller Al particles are less sensitive to temperature changes. For 500 μm Al particles, the time it takes for ignition to occur increases from 163 ms to 218 ms as the temperature changes within the same range, resulting in a smaller percentage increase of 33.7 %. To better understand the ignition process, a model was created that accounts for the effects of both particle size and temperature on ignition behaviour. In the early stages of ignition, the main source of heat is convective heat transfer, which plays a crucial role in initiating the ignition process. Once the Al particles have melted completely, surface chemical reactions become a significant source of heat. This model accurately describes the influence of the initial temperature on the ignition process and energy transfer, showing an average deviation of 7.03 % between predicted ignition delay times for different temperatures and particle sizes compared to experimental data. Overall, this study enhances our understanding of the ignition and combustion processes of Al particles across a range of temperatures.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 430-437"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2025-12-31DOI: 10.1016/j.actaastro.2025.12.061
ShangBiao Sun , JianGuo Yan , WuTong Gao , Chongyang Wang , Zohaib Afzal , Zhen Wang , Jean-Pierre Barriot
Callisto’s internal structure remains poorly constrained due to the limited resolution of existing gravity field models derived from Galileo flybys. Unlike ESA’s JUICE and NASA’s Europa Clipper missions, China’s upcoming Tianwen-4 mission will orbit Callisto, providing a unique opportunity to determine its high-degree gravity field and tidal Love number. Using in-house precision orbit determination software and simulated radio tracking data, this study investigates the capability of the China Deep Space Network (CDSN) to estimate Callisto’s gravity field under various observation geometries and tracking configurations. The results show that reducing Doppler noise from 0.1 to 0.01 mm/s improves precision by an order of magnitude. At altitudes of 200 km and 400 km, coefficients can be resolved up to degrees 80 and 50, respectively. Increasing orbital eccentricity from 0 to 0.1 degrades estimation accuracy. Combining range and VLBI observables improves the accuracy of low-degree gravity coefficients by about 1.4 and 1.5 times, respectively. Combining all CDSN stations further improves the estimation accuracy across all degrees. Extending tracking duration from 6 to 12 months improves estimated accuracy and spatial resolution. The best and worst gravity field estimations provide a quantitative basis for comparing orbital prediction accuracy and Callisto’s gravity anomaly uncertainties. The lowest accuracy in the estimation occurs at an orbital altitude of 400 km, with a 1- uncertainty of 0.033, which remains sufficient to detect the potential presence of a subsurface ocean. These results demonstrate the strong potential of CDSN-supported Tianwen-4 mission to achieve high-precision gravity estimation and internal structure characterization of Callisto.
{"title":"Gravity field estimation of Callisto using tracking data for the upcoming Tianwen-4 mission","authors":"ShangBiao Sun , JianGuo Yan , WuTong Gao , Chongyang Wang , Zohaib Afzal , Zhen Wang , Jean-Pierre Barriot","doi":"10.1016/j.actaastro.2025.12.061","DOIUrl":"10.1016/j.actaastro.2025.12.061","url":null,"abstract":"<div><div>Callisto’s internal structure remains poorly constrained due to the limited resolution of existing gravity field models derived from Galileo flybys. Unlike ESA’s JUICE and NASA’s Europa Clipper missions, China’s upcoming Tianwen-4 mission will orbit Callisto, providing a unique opportunity to determine its high-degree gravity field and tidal Love number. Using in-house precision orbit determination software and simulated radio tracking data, this study investigates the capability of the China Deep Space Network (CDSN) to estimate Callisto’s gravity field under various observation geometries and tracking configurations. The results show that reducing Doppler noise from 0.1 to 0.01 mm/s improves precision by an order of magnitude. At altitudes of 200 km and 400 km, coefficients can be resolved up to degrees 80 and 50, respectively. Increasing orbital eccentricity from 0 to 0.1 degrades estimation accuracy. Combining range and VLBI observables improves the accuracy of low-degree gravity coefficients by about 1.4 and 1.5 times, respectively. Combining all CDSN stations further improves the estimation accuracy across all degrees. Extending tracking duration from 6 to 12 months improves estimated accuracy and spatial resolution. The best and worst gravity field estimations provide a quantitative basis for comparing orbital prediction accuracy and Callisto’s gravity anomaly uncertainties. The lowest accuracy in the <span><math><msub><mrow><mi>k</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> estimation occurs at an orbital altitude of 400 km, with a 1-<span><math><mi>σ</mi></math></span> uncertainty of 0.033, which remains sufficient to detect the potential presence of a subsurface ocean. These results demonstrate the strong potential of CDSN-supported Tianwen-4 mission to achieve high-precision gravity estimation and internal structure characterization of Callisto.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 181-191"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-07DOI: 10.1016/j.actaastro.2025.12.044
Shengjun Zeng, Wei Fan, Hui Ren
Motivated by a hybrid motivation mechanism, the photonic electric solar wind sail (E-sail) spacecraft is regarded as an innovative propellant-free propulsion concept for interstellar missions. Under typical operating conditions, the solar wind dynamic pressure (SWDP) interacts with the charged main tether to generate the primary thrust, while the solar radiation pressure (SRP) acts on the photonic film at the end of each main tether to generate attitude adjustment torque. Compared with the classical E-sail spacecraft, the photonic E-sail spacecraft enables active spinning control by regulating the inclination of the extra photonic films, while an effective spinning control strategy for the rigid–flexible coupled model remains underexplored. Based on the full-scale dynamical model derived by the referenced nodal coordinate formulation (RNCF) approach, this work investigates an active spinning control strategy for the photonic E-sail spacecraft. The reflectance control device (RCD) is integrated into the structural design of the photonic film, which enables active optical parameters modulation to regulate the solar radiation pressure (SRP) induced thrust. A practical spin rate feedback control strategy for the photonic E-sail spacecraft is proposed, where the reflectance distribution across its partitions drives the photonic film inclination, thereby indirectly manipulating the overall spin rate. By numerical simulations with different configurations, the dynamical characteristics of the varying optical parameters on the full-scale photonic E-sail spacecraft model are analyzed. Plus, the effectiveness of the proposed active spinning manipulation mechanisms is validated. Furthermore, the collaborative simulation on the spinning control module and the orientation control module demonstrates the feasibility of the simultaneous manipulation of the spin rate and the sail plane rotation parameters. The proposed spinning control strategy provides an accurate and efficient approach for comprehensive attitude control for the spinning spacecrafts.
{"title":"Active spinning control for a flexible photonic electric solar wind sail spacecraft","authors":"Shengjun Zeng, Wei Fan, Hui Ren","doi":"10.1016/j.actaastro.2025.12.044","DOIUrl":"10.1016/j.actaastro.2025.12.044","url":null,"abstract":"<div><div>Motivated by a hybrid motivation mechanism, the photonic electric solar wind sail (E-sail) spacecraft is regarded as an innovative propellant-free propulsion concept for interstellar missions. Under typical operating conditions, the solar wind dynamic pressure (SWDP) interacts with the charged main tether to generate the primary thrust, while the solar radiation pressure (SRP) acts on the photonic film at the end of each main tether to generate attitude adjustment torque. Compared with the classical E-sail spacecraft, the photonic E-sail spacecraft enables active spinning control by regulating the inclination of the extra photonic films, while an effective spinning control strategy for the rigid–flexible coupled model remains underexplored. Based on the full-scale dynamical model derived by the referenced nodal coordinate formulation (RNCF) approach, this work investigates an active spinning control strategy for the photonic E-sail spacecraft. The reflectance control device (RCD) is integrated into the structural design of the photonic film, which enables active optical parameters modulation to regulate the solar radiation pressure (SRP) induced thrust. A practical spin rate feedback control strategy for the photonic E-sail spacecraft is proposed, where the reflectance distribution across its partitions drives the photonic film inclination, thereby indirectly manipulating the overall spin rate. By numerical simulations with different configurations, the dynamical characteristics of the varying optical parameters on the full-scale photonic E-sail spacecraft model are analyzed. Plus, the effectiveness of the proposed active spinning manipulation mechanisms is validated. Furthermore, the collaborative simulation on the spinning control module and the orientation control module demonstrates the feasibility of the simultaneous manipulation of the spin rate and the sail plane rotation parameters. The proposed spinning control strategy provides an accurate and efficient approach for comprehensive attitude control for the spinning spacecrafts.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 409-429"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2025-12-30DOI: 10.1016/j.actaastro.2025.12.059
Hang Wu , Xi Zeng , Hui Liu , Hong Liu , Beizhen Xie
In-situ utilization of Martian water resources is imperative for sustained long-term exploration missions. To address perchlorate contamination that hinders its use in Bioregenerative Life Support Systems (BLSS), this study developed a simulated Martian water (SMW) formula (validated composition, containing 500 mg/L ClO4− and characteristic ions) and evaluated its microbial purification and subsequent plant cultivation potential. The results showed that screened strains Dechloromonas agitata and Brucella intermedia exhibited ClO4− removal capabilities in the SMW. Under optimized conditions of inoculum amount (OD600 = 0.2), pH 7.5, and extra nutrients (CH3COONa 1.8 g/L, NH4Cl 0.25 g/L, NaH2PO4 0.6 g/L), Dechloromonas agitata achieved complete degradation of 500 mg/L ClO4− within 10 days, while Brucella intermedia accomplished full degradation in 5-fold diluted SMW within 15 days. Cultivation of ClO4−-sensitive plants (wheat, lettuce) using the purified SMW resulted in 95 % seed germination and significantly enhanced morphological indices (leaf length, plant height) and physiological parameters (photosynthetic pigment content, net photosynthetic rate) compared to the untreated control. Critically, no ClO4− residue was detected in plant tissues cultivated with the purified SMW. These results demonstrate that the developed technology effectively produces water meeting BLSS cultivation requirements, thereby offering a viable pathway for in-situ Martian water utilization.
{"title":"Microbial purification of perchlorate in a simulated Martian water to ensure its plant cultivation for Martian BLSS","authors":"Hang Wu , Xi Zeng , Hui Liu , Hong Liu , Beizhen Xie","doi":"10.1016/j.actaastro.2025.12.059","DOIUrl":"10.1016/j.actaastro.2025.12.059","url":null,"abstract":"<div><div>In-situ utilization of Martian water resources is imperative for sustained long-term exploration missions. To address perchlorate contamination that hinders its use in Bioregenerative Life Support Systems (BLSS), this study developed a simulated Martian water (SMW) formula (validated composition, containing 500 mg/L ClO<sub>4</sub><sup>−</sup> and characteristic ions) and evaluated its microbial purification and subsequent plant cultivation potential. The results showed that screened strains <em>Dechloromonas agitata</em> and <em>Brucella intermedia</em> exhibited ClO<sub>4</sub><sup>−</sup> removal capabilities in the SMW. Under optimized conditions of inoculum amount (OD<sub>600</sub> = 0.2), pH 7.5, and extra nutrients (CH<sub>3</sub>COONa 1.8 g/L, NH<sub>4</sub>Cl 0.25 g/L, NaH<sub>2</sub>PO<sub>4</sub> 0.6 g/L), <em>Dechloromonas agitata</em> achieved complete degradation of 500 mg/L ClO<sub>4</sub><sup>−</sup> within 10 days, while <em>Brucella intermedia</em> accomplished full degradation in 5-fold diluted SMW within 15 days. Cultivation of ClO<sub>4</sub><sup>−</sup>-sensitive plants (wheat, lettuce) using the purified SMW resulted in 95 % seed germination and significantly enhanced morphological indices (leaf length, plant height) and physiological parameters (photosynthetic pigment content, net photosynthetic rate) compared to the untreated control. Critically, no ClO<sub>4</sub><sup>−</sup> residue was detected in plant tissues cultivated with the purified SMW. These results demonstrate that the developed technology effectively produces water meeting BLSS cultivation requirements, thereby offering a viable pathway for in-situ Martian water utilization.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 224-233"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-10DOI: 10.1016/j.actaastro.2026.01.021
Zhihua Liang , Wudong Deng , Yunfeng Dong
Cluster satellites' component-level collaborative observation enables on-demand stitching of the observation chain. By responding directly to dynamic targets and environmental changes, this capability represents a key trend in meeting future complex observation requirements. Mission planning is critical to realizing this collaboration. Existing methods typically employ subsystem-level models and reinforcement learning algorithms to plan missions under deterministic operational flows. However, realizing on-demand stitching requires mission planning to address the challenge of nested space sparsity optimization while accurately reflecting component-level characteristics. To address this, this paper utilizes multi-granularity digital twin models to achieve component-level on-demand modeling. We introduce the logical dimension from systems engineering to decouple nested space sparsity. Following the self-similar logical steps of synthesis, analysis, and assessment, the optimization problem is transformed into a set of high-cohesion, low-coupling sub-problems, thereby guiding the reinforcement learning process. By switching computational models based on the specific requirements of logical dimensional reinforcement learning, we established the multi-granularity digital twin logical dimensional reinforcement learning method to realize on-demand stitching of the observation chain. To validate this capability, this paper designed typical cluster satellite observation scenarios corrected by real telemetry parameters. Using the number of confirmed unknown moving targets as a performance indicator, we tested the ability of our method and deterministic planning methods to respond to complex demands under dynamic environmental conditions. Furthermore, sparsity and feature analyses were conducted to verify the rationality of the proposed approach in optimizing nested space sparsity. The results demonstrate that the proposed method successfully achieves on-demand stitching of the observation chain for cluster satellites. This approach provides an effective pathway for adapting to future complex observation requirements and serves as an exemplar for applying systems engineering to guide machine learning in solving complex problems.
{"title":"A logical dimensional reinforcement learning approach for component-level collaborative planning in cluster satellites","authors":"Zhihua Liang , Wudong Deng , Yunfeng Dong","doi":"10.1016/j.actaastro.2026.01.021","DOIUrl":"10.1016/j.actaastro.2026.01.021","url":null,"abstract":"<div><div>Cluster satellites' component-level collaborative observation enables on-demand stitching of the observation chain. By responding directly to dynamic targets and environmental changes, this capability represents a key trend in meeting future complex observation requirements. Mission planning is critical to realizing this collaboration. Existing methods typically employ subsystem-level models and reinforcement learning algorithms to plan missions under deterministic operational flows. However, realizing on-demand stitching requires mission planning to address the challenge of nested space sparsity optimization while accurately reflecting component-level characteristics. To address this, this paper utilizes multi-granularity digital twin models to achieve component-level on-demand modeling. We introduce the logical dimension from systems engineering to decouple nested space sparsity. Following the self-similar logical steps of synthesis, analysis, and assessment, the optimization problem is transformed into a set of high-cohesion, low-coupling sub-problems, thereby guiding the reinforcement learning process. By switching computational models based on the specific requirements of logical dimensional reinforcement learning, we established the multi-granularity digital twin logical dimensional reinforcement learning method to realize on-demand stitching of the observation chain. To validate this capability, this paper designed typical cluster satellite observation scenarios corrected by real telemetry parameters. Using the number of confirmed unknown moving targets as a performance indicator, we tested the ability of our method and deterministic planning methods to respond to complex demands under dynamic environmental conditions. Furthermore, sparsity and feature analyses were conducted to verify the rationality of the proposed approach in optimizing nested space sparsity. The results demonstrate that the proposed method successfully achieves on-demand stitching of the observation chain for cluster satellites. This approach provides an effective pathway for adapting to future complex observation requirements and serves as an exemplar for applying systems engineering to guide machine learning in solving complex problems.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 575-593"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2025-12-30DOI: 10.1016/j.actaastro.2025.12.047
Miguel Gavira-Aladro , Claudio Bombardelli
The hypothetical asteroid threat exercise for the 2025 Planetary Defense Conference presents an intriguing trajectory design challenge for potential deflection missions, as the considerably high eccentricity and inclination of the fictitious asteroid ensure considerable relative arrival velocities for kinetic impactors. In addition, the extended 17-year interval between the initial discovery and the possible impact date allows for the exploitation of multiple gravity assist (MGA) trajectories involving inner solar system planets and Jupiter. This enhances the deflection capability of a kinetic impactor and, additionally, facilitates an otherwise very expensive low-relative-velocity rendezvous reconnaissance mission.
In this work, we utilize a rapid, Lambert-free, sequence-independent trajectory-finding algorithm previously developed by the authors, capable of computing all viable MGA trajectories to the asteroid before the expected impact. Additionally, this solver has been improved to include resonance chains in the trajectories. From this full characterization of the solution space, suitable reconnaissance and impact solutions are selected. Gravity assists are key in order to achieve a feasible rendezvous without requiring a high-energy launch (C3 < 50 km²/s²), with optimal phasing occurring near perihelion. Moreover, some of the most promising trajectories feature multiple resonant legs.
Interestingly, gravity-assist impact trajectories—impacting almost tangentially and near perihelion—appear to be more effective than direct impact trajectories in the proposed scenario. A reconnaissance rendezvous mission followed by a kinetic impact deflection mission is shown to be technologically feasible with carefully designed MGA trajectories, offering multiple launch and arrival opportunities.
{"title":"Exhaustive search of gravity assist trajectories for rapid reconnaissance and deflection of fictitious asteroid PDC2025","authors":"Miguel Gavira-Aladro , Claudio Bombardelli","doi":"10.1016/j.actaastro.2025.12.047","DOIUrl":"10.1016/j.actaastro.2025.12.047","url":null,"abstract":"<div><div>The hypothetical asteroid threat exercise for the 2025 Planetary Defense Conference presents an intriguing trajectory design challenge for potential deflection missions, as the considerably high eccentricity and inclination of the fictitious asteroid ensure considerable relative arrival velocities for kinetic impactors. In addition, the extended 17-year interval between the initial discovery and the possible impact date allows for the exploitation of multiple gravity assist (MGA) trajectories involving inner solar system planets and Jupiter. This enhances the deflection capability of a kinetic impactor and, additionally, facilitates an otherwise very expensive low-relative-velocity rendezvous reconnaissance mission.</div><div>In this work, we utilize a rapid, Lambert-free, sequence-independent trajectory-finding algorithm previously developed by the authors, capable of computing all viable MGA trajectories to the asteroid before the expected impact. Additionally, this solver has been improved to include resonance chains in the trajectories. From this full characterization of the solution space, suitable reconnaissance and impact solutions are selected. Gravity assists are key in order to achieve a feasible rendezvous without requiring a high-energy launch (C3 < 50 km²/s²), with optimal phasing occurring near perihelion. Moreover, some of the most promising trajectories feature multiple resonant legs.</div><div>Interestingly, gravity-assist impact trajectories—impacting almost tangentially and near perihelion—appear to be more effective than direct impact trajectories in the proposed scenario. A reconnaissance rendezvous mission followed by a kinetic impact deflection mission is shown to be technologically feasible with carefully designed MGA trajectories, offering multiple launch and arrival opportunities.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 325-345"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-05DOI: 10.1016/j.actaastro.2026.01.008
Wang Zhao , Shujun Tan
A dimensionality reduction method addressing the high-dimensional and singular nature of Pogo state-space models is studied, beneficial for advancing active suppression techniques. A comprehensive approach integrating eigenspace transformation with Modal Cost Analysis (MCA) is proposed. Direct modal analysis of the coupled Pogo system yields unreliable modal costs due to distinct propulsion and structural system characteristics. Therefore, the coupling between systems is explicitly considered. Suitable inputs and outputs are designed for each system. Specifically, the Pogo system is first decoupled via eigenspace transformation. MCA is then performed, retaining high-cost modes within the Pogo system to construct the reduced-dimensional model. Validation through frequency domain analysis and time domain simulation demonstrates that the method effectively retains high-cost modes under varying conditions, yielding a more accurate reduced-dimensional model. The framework offers generalized applicability to reusable rocket development.
{"title":"Model reduction of pogo suppression for liquid launch vehicles via decoupled modal cost selection","authors":"Wang Zhao , Shujun Tan","doi":"10.1016/j.actaastro.2026.01.008","DOIUrl":"10.1016/j.actaastro.2026.01.008","url":null,"abstract":"<div><div>A dimensionality reduction method addressing the high-dimensional and singular nature of Pogo state-space models is studied, beneficial for advancing active suppression techniques. A comprehensive approach integrating eigenspace transformation with Modal Cost Analysis (MCA) is proposed. Direct modal analysis of the coupled Pogo system yields unreliable modal costs due to distinct propulsion and structural system characteristics. Therefore, the coupling between systems is explicitly considered. Suitable inputs and outputs are designed for each system. Specifically, the Pogo system is first decoupled via eigenspace transformation. MCA is then performed, retaining high-cost modes within the Pogo system to construct the reduced-dimensional model. Validation through frequency domain analysis and time domain simulation demonstrates that the method effectively retains high-cost modes under varying conditions, yielding a more accurate reduced-dimensional model. The framework offers generalized applicability to reusable rocket development.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 473-483"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2025-12-31DOI: 10.1016/j.actaastro.2025.12.056
Yuqi Wei, Fang Chen, Yingxuan Qin, Liaolei He, Yang Wang
The method of Direct Simulation of Monte Carlo (DSMC) is important for the simulation of hypersonic multi-regime aerodynamics. In this paper, a self-supervised denoising method with physical constraint and noise assistance is proposed to eliminate the random noise in DSMC. This method theoretically only requires two samples as input and can directly distinguish the flow fields with high fidelity by simultaneously learning the noise differences and structural similarities between noisy samples with no need of clean data. Investigation into this method shows that it has better effect than traditional filtering methods. The physical residuals of flow fields after denoising are closer to the real residuals, indicating its strong physical interpretability. The noise-assisted strategy can achieve higher reliability, as evidenced by the Bootstrap interval estimation, which shows it less affected by the randomness of neural networks. The generalization analysis shows that it has strong generalization ability, and can reduce the number of DSMC particles required to obtain flow field with the same level of structure similarity by one order of magnitude, and the number of DSMC particles required to obtain similar surface pressure distribution by two orders of magnitude. This method may have important value for improving the computational efficiency of DSMC in the future.
{"title":"Physics-informed and noise-assisted self-supervised learning with dual samples input for hypersonic DSMC denoising","authors":"Yuqi Wei, Fang Chen, Yingxuan Qin, Liaolei He, Yang Wang","doi":"10.1016/j.actaastro.2025.12.056","DOIUrl":"10.1016/j.actaastro.2025.12.056","url":null,"abstract":"<div><div>The method of Direct Simulation of Monte Carlo (DSMC) is important for the simulation of hypersonic multi-regime aerodynamics. In this paper, a self-supervised denoising method with physical constraint and noise assistance is proposed to eliminate the random noise in DSMC. This method theoretically only requires two samples as input and can directly distinguish the flow fields with high fidelity by simultaneously learning the noise differences and structural similarities between noisy samples with no need of clean data. Investigation into this method shows that it has better effect than traditional filtering methods. The physical residuals of flow fields after denoising are closer to the real residuals, indicating its strong physical interpretability. The noise-assisted strategy can achieve higher reliability, as evidenced by the Bootstrap interval estimation, which shows it less affected by the randomness of neural networks. The generalization analysis shows that it has strong generalization ability, and can reduce the number of DSMC particles required to obtain flow field with the same level of structure similarity by one order of magnitude, and the number of DSMC particles required to obtain similar surface pressure distribution by two orders of magnitude. This method may have important value for improving the computational efficiency of DSMC in the future.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 153-169"},"PeriodicalIF":3.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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