Pub Date : 2026-01-12DOI: 10.1016/j.actaastro.2026.01.020
Tianshan Dong , Xiaobing Ma , Wenyan Zhou , Lin Lu
Lunar Orbit Rendezvous (LOR) is a crucial mode for crewed lunar missions. Unlike the Apollo mission, a variant of LOR involving two launches and the assembly of modules in lunar orbit has emerged as a notable pattern in recent lunar return missions. This paper presents a methodology for determining the launch window of a crewed lunar mission using LOR with two launches. First, nominal launch windows are defined by constructing its calculation model based on the flight scheme and integrated launch windows are introduced considering a delay strategy. Second, a method for determining nominal launch windows based on mission geometry is proposed, which solves the nominal launch window in a tiered analytical process by constraints’ temporal geometry. Finally, the integrated launch windows are first estimated by orbital plane matching and then solved by introducing virtual planes. Numerical simulations for nominal launch windows and integrated launch windows validate the proposed method and the satisfaction of the constraints. The methodology offers a systematic solution to the launch window for crewed lunar missions with lunar orbit rendezvous and two launches and addresses the integrated launch window for spacecraft under a complex delay strategy.
{"title":"Launch window design for crewed lunar mission with lunar orbit rendezvous and two launches","authors":"Tianshan Dong , Xiaobing Ma , Wenyan Zhou , Lin Lu","doi":"10.1016/j.actaastro.2026.01.020","DOIUrl":"10.1016/j.actaastro.2026.01.020","url":null,"abstract":"<div><div>Lunar Orbit Rendezvous (LOR) is a crucial mode for crewed lunar missions. Unlike the Apollo mission, a variant of LOR involving two launches and the assembly of modules in lunar orbit has emerged as a notable pattern in recent lunar return missions. This paper presents a methodology for determining the launch window of a crewed lunar mission using LOR with two launches. First, nominal launch windows are defined by constructing its calculation model based on the flight scheme and integrated launch windows are introduced considering a delay strategy. Second, a method for determining nominal launch windows based on mission geometry is proposed, which solves the nominal launch window in a tiered analytical process by constraints’ temporal geometry. Finally, the integrated launch windows are first estimated by orbital plane matching and then solved by introducing virtual planes. Numerical simulations for nominal launch windows and integrated launch windows validate the proposed method and the satisfaction of the constraints. The methodology offers a systematic solution to the launch window for crewed lunar missions with lunar orbit rendezvous and two launches and addresses the integrated launch window for spacecraft under a complex delay strategy.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"242 ","pages":"Pages 58-73"},"PeriodicalIF":3.4,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962431","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 : 2026-01-10DOI: 10.1016/j.actaastro.2026.01.022
Sheena I. Dev , Nikole D. Moody , Diana P. Arias , Suzanne T. Bell
Background
Current astronauts on the International Space Station have scheduled time to connect with their families via virtual audio and video private family conferences (PFCs). However, one-way communication delays expected to range from 4 to 12 s during lunar missions represent a significant paradigm shift for PFCs which have thus far operated with real-time communication. The objective of this study was to determine the effect of lunar communication delays on the expected benefits of PFCs in astronaut-like participants and their families.
Methods
Thirty-five primary participants were recruited to approximate astronaut demographics at NASA Johnson Space Center in Houston, Texas. They were asked to identify a family member living outside of Houston to join as their study partner. Each study pair participated in six weekly virtual audiovisual PFC sessions conducted under 0, 4, 6, 8, 10, or 12 s one-way delays. Relationship and individual well-being outcomes were assessed before and after each PFC. Communication quality was assessed after each PFC in reference to the delay implemented. Linear mixed models with planned contrasts examined the impact of each PFC on relationship, individual well-being, and communication quality.
Results
PFCs improved relationship outcomes relative to baseline regardless of the delay. Compared to PFCs with no delays, greater decrements to relationships and individual well-being were observed after PFCs with 8 s one-way delays or longer. Participants also indicated all delay latencies significantly reduced their communication quality and would impact their relationships if they were required to continue communicating under those conditions for six months.
Conclusion
PFCs benefit long distance relationships among astronaut-like families. While participants generally tolerated shorter communication delays in this time limited laboratory setting, our results suggest that PFCs with communication delays, especially 8 s or longer, may not be sufficient to maintain family bonds in future long duration lunar missions. These findings underscore the importance of maintaining access to family and friends during spaceflight and provide a foundation from which innovative solutions can be crafted to preserve connections despite obstacles to communication.
{"title":"Fly me to the moon: Family conferencing with communication delays on lunar missions","authors":"Sheena I. Dev , Nikole D. Moody , Diana P. Arias , Suzanne T. Bell","doi":"10.1016/j.actaastro.2026.01.022","DOIUrl":"10.1016/j.actaastro.2026.01.022","url":null,"abstract":"<div><h3>Background</h3><div>Current astronauts on the International Space Station have scheduled time to connect with their families via virtual audio and video private family conferences (PFCs). However, one-way communication delays expected to range from 4 to 12 s during lunar missions represent a significant paradigm shift for PFCs which have thus far operated with real-time communication. The objective of this study was to determine the effect of lunar communication delays on the expected benefits of PFCs in astronaut-like participants and their families.</div></div><div><h3>Methods</h3><div>Thirty-five primary participants were recruited to approximate astronaut demographics at NASA Johnson Space Center in Houston, Texas. They were asked to identify a family member living outside of Houston to join as their study partner. Each study pair participated in six weekly virtual audiovisual PFC sessions conducted under 0, 4, 6, 8, 10, or 12 s one-way delays. Relationship and individual well-being outcomes were assessed before and after each PFC. Communication quality was assessed after each PFC in reference to the delay implemented. Linear mixed models with planned contrasts examined the impact of each PFC on relationship, individual well-being, and communication quality.</div></div><div><h3>Results</h3><div>PFCs improved relationship outcomes relative to baseline regardless of the delay. Compared to PFCs with no delays, greater decrements to relationships and individual well-being were observed after PFCs with 8 s one-way delays or longer. Participants also indicated all delay latencies significantly reduced their communication quality and would impact their relationships if they were required to continue communicating under those conditions for six months.</div></div><div><h3>Conclusion</h3><div>PFCs benefit long distance relationships among astronaut-like families. While participants generally tolerated shorter communication delays in this time limited laboratory setting, our results suggest that PFCs with communication delays, especially 8 s or longer, may not be sufficient to maintain family bonds in future long duration lunar missions. These findings underscore the importance of maintaining access to family and friends during spaceflight and provide a foundation from which innovative solutions can be crafted to preserve connections despite obstacles to communication.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"242 ","pages":"Pages 48-57"},"PeriodicalIF":3.4,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039452","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 : 2026-01-10DOI: 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":"2026-01-10","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}
FACTORS is an M-class mission proposal led by JAXA/ISAS. It aims to elucidate energy coupling mechanisms and mass transport between Earth and space, at around 350–3500 km altitude in high latitude regions. Measurements of the electromagnetic field, particle sampling, and auroral imaging are planned. Simultaneous data at several kilometres to tens of kilometres apart will be obtained, using two satellites in formation flight in an eccentric polar orbit. Differential aerodynamic drag offers a promising resource for propellant-free formation control, since the perigee is located in the atmosphere. A control method for an in-track linear formation is developed and tested using a high-fidelity numerical orbit simulator. Disturbances are added to represent attitude control error, aerodynamic lift, and open-loop command uplink with space weather prediction error. Good performance is obtained even for close-proximity operations with km-scale separation. Based on the results, fully aerodynamic control is possible, though a thruster is desirable for perigee altitude adjustment and out-of-plane manoeuvring. To the authors’ knowledge, this is the first detailed study on formation flight control via differential drag in an eccentric orbit.
{"title":"Feasibility assessment of formation flight control by differential drag in eccentric orbit for the FACTORS mission","authors":"Maximilien Berthet , Yusuke Maru , Yoshifumi Saito , Takefumi Mitani , Iku Shinohara , Kazushi Asamura","doi":"10.1016/j.actaastro.2026.01.017","DOIUrl":"10.1016/j.actaastro.2026.01.017","url":null,"abstract":"<div><div>FACTORS is an M-class mission proposal led by JAXA/ISAS. It aims to elucidate energy coupling mechanisms and mass transport between Earth and space, at around 350–3500 km altitude in high latitude regions. Measurements of the electromagnetic field, particle sampling, and auroral imaging are planned. Simultaneous data at several kilometres to tens of kilometres apart will be obtained, using two satellites in formation flight in an eccentric polar orbit. Differential aerodynamic drag offers a promising resource for propellant-free formation control, since the perigee is located in the atmosphere. A control method for an in-track linear formation is developed and tested using a high-fidelity numerical orbit simulator. Disturbances are added to represent attitude control error, aerodynamic lift, and open-loop command uplink with space weather prediction error. Good performance is obtained even for close-proximity operations with km-scale separation. Based on the results, fully aerodynamic control is possible, though a thruster is desirable for perigee altitude adjustment and out-of-plane manoeuvring. To the authors’ knowledge, this is the first detailed study on formation flight control via differential drag in an eccentric orbit.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 556-574"},"PeriodicalIF":3.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978438","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 : 2026-01-08DOI: 10.1016/j.actaastro.2025.12.060
Luís Filipe Pino Gonçalves , Nevan Simone , A.K. de Almeida Jr , Domingos Barbosa , Moriba Jah , Timothée Vaillant , Bruno Coelho , Alexandre C.M. Correia
Light-curve inversion for anthropogenic space objects (ASOs) is ill-posed when performed in a single band, which leads to non-unique combinations of attitude and material parameters. We present a physically grounded forward model based on a Cook–Torrance bidirectional reflectance distribution function, explicit shadowing by Earth and self-occlusion, and a satellite-centred geometry. We cast attitude–material retrieval as a constrained optimisation problem and use multi-colour light curves (Johnson–Cousins , , ) to regularise the inversion by coupling wavelength-invariant parameters. On four space objects of distinct morphology, the multi-colour constraint improves fit quality and narrows the admissible solution set relative to panchromatic inversions. We report parameter uncertainties from multi-start annealing and provide sensitivity of the fit to key BRDF and attitude parameters. Results support multi-colour optical surveys as an efficient path to unambiguous ASO characterisation from a single site.
{"title":"Anthropogenic Space Object attitude and material characterisation through multi-colour light curve inversion","authors":"Luís Filipe Pino Gonçalves , Nevan Simone , A.K. de Almeida Jr , Domingos Barbosa , Moriba Jah , Timothée Vaillant , Bruno Coelho , Alexandre C.M. Correia","doi":"10.1016/j.actaastro.2025.12.060","DOIUrl":"10.1016/j.actaastro.2025.12.060","url":null,"abstract":"<div><div>Light-curve inversion for anthropogenic space objects (ASOs) is ill-posed when performed in a single band, which leads to non-unique combinations of attitude and material parameters. We present a physically grounded forward model based on a Cook–Torrance bidirectional reflectance distribution function, explicit shadowing by Earth and self-occlusion, and a satellite-centred geometry. We cast attitude–material retrieval as a constrained optimisation problem and use multi-colour light curves (Johnson–Cousins <span><math><mi>B</mi></math></span>, <span><math><mi>V</mi></math></span>, <span><math><mi>R</mi></math></span>) to regularise the inversion by coupling wavelength-invariant parameters. On four space objects of distinct morphology, the multi-colour constraint improves fit quality and narrows the admissible solution set relative to panchromatic inversions. We report parameter uncertainties from multi-start annealing and provide sensitivity of the fit to key BRDF and attitude parameters. Results support multi-colour optical surveys as an efficient path to unambiguous ASO characterisation from a single site.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 378-408"},"PeriodicalIF":3.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940442","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 : 2026-01-08DOI: 10.1016/j.actaastro.2026.01.016
Vladislav Zubko
This work develops low-energy spacecraft (SC) trajectories using Venus gravity assists to study asteroids during heliocentric transfer segments between planetary encounters. The study focuses on potentially hazardous asteroids (PHAs) as primary exploration targets. This paper proposes a method for calculating SC trajectories that enable asteroid flybys after a Venus gravity assist. The method involves formulating and solving an optimization problem to design trajectories incorporating flybys of selected asteroids and Venus. Trajectories are calculated using two-body dynamics by solving the Lambert problem. A preliminary search for candidate asteroids uses an algorithm to narrow the search space of the optimization problem. This algorithm uses the V-infinity globe technique to connect planetary gravity assists with resonant orbits. The resonant orbit in this case serves as an initial approximation for the SC’s trajectory between two successive planetary flybys. Four flight schemes were analyzed, including multiple flybys of Venus and asteroids, with the possibility of an SC returning to Earth. The proposed solutions reduce flight time between asteroid approaches, increase gravity assist frequency, and enhance mission design flexibility. The use of Venus gravity assists and resonant orbits ensures a close encounter with at least one asteroid during the SC’s trajectory between two consecutive flybys of Venus, and demonstrates the feasibility of periodic Venus gravity assists and encounters with PHAs. The developed method was applied to construct trajectories that allow an SC to approach both co-orbital asteroids with Venus and PHAs via multiple Venus gravity assists. An additional study was carried out to identify asteroids accessible during the Earth–Venus segment in launch windows between 2029 and 2050.
{"title":"The feasibility of potentially hazardous asteroids flybys using multiple Venus gravity assists","authors":"Vladislav Zubko","doi":"10.1016/j.actaastro.2026.01.016","DOIUrl":"10.1016/j.actaastro.2026.01.016","url":null,"abstract":"<div><div>This work develops low-energy spacecraft (SC) trajectories using Venus gravity assists to study asteroids during heliocentric transfer segments between planetary encounters. The study focuses on potentially hazardous asteroids (PHAs) as primary exploration targets. This paper proposes a method for calculating SC trajectories that enable asteroid flybys after a Venus gravity assist. The method involves formulating and solving an optimization problem to design trajectories incorporating flybys of selected asteroids and Venus. Trajectories are calculated using two-body dynamics by solving the Lambert problem. A preliminary search for candidate asteroids uses an algorithm to narrow the search space of the optimization problem. This algorithm uses the V-infinity globe technique to connect planetary gravity assists with resonant orbits. The resonant orbit in this case serves as an initial approximation for the SC’s trajectory between two successive planetary flybys. Four flight schemes were analyzed, including multiple flybys of Venus and asteroids, with the possibility of an SC returning to Earth. The proposed solutions reduce flight time between asteroid approaches, increase gravity assist frequency, and enhance mission design flexibility. The use of Venus gravity assists and resonant orbits ensures a close encounter with at least one asteroid during the SC’s trajectory between two consecutive flybys of Venus, and demonstrates the feasibility of periodic Venus gravity assists and encounters with PHAs. The developed method was applied to construct trajectories that allow an SC to approach both co-orbital asteroids with Venus and PHAs via multiple Venus gravity assists. An additional study was carried out to identify asteroids accessible during the Earth–Venus segment in launch windows between 2029 and 2050.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 504-528"},"PeriodicalIF":3.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978440","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 : 2026-01-07DOI: 10.1016/j.actaastro.2026.01.004
Gefei Shi , Zheng H. Zhu
This work develops the rigid-flexible coupled dynamic model of a partial space elevator transporting a slender structural payload by the climber during cross-orbit payload transfer. The payload is modeled by Euler–Bernoulli beam theory, and analysis shows that even small bending deformation of the payload can induce large attitude motion of the climber-payload assembly due to strong orbit-rigid–flexible coupling. To quantify this behavior, a closed-form expression is derived for the steady bending deformation of the payload under the gravity-gradient effect. Building on this analytical insight, a nonlinear compensation control torque is formulated to suppress attitude motion caused by rigid–flexible coupling without requiring impractically large control torques. To enhance control robustness, a super-twisting sliding mode control scheme is proposed by embedding the forward control law within a Lyapunov stability framework. This combined strategy eliminates residual dynamics and reduces the chattering inherent in sliding mode control while ensuring global attitude stability. Numerical simulations verify that the proposed strategy significantly reduces the attitude excursions of the climber-payload assembly while keeping the required control torques within the capacity of reaction wheels on the climber (rigid body). Overall, this work establishes a nonlinear dynamic framework for tethered transport systems with slender structure payloads and provides the first validated control solution enabling safe, stable, and efficient operation of partial space elevator transporting slender structure payloads.
{"title":"Attitude stabilization of slender payloads in partial space elevator transport by super-twisting sliding mode control","authors":"Gefei Shi , Zheng H. Zhu","doi":"10.1016/j.actaastro.2026.01.004","DOIUrl":"10.1016/j.actaastro.2026.01.004","url":null,"abstract":"<div><div>This work develops the rigid-flexible coupled dynamic model of a partial space elevator transporting a slender structural payload by the climber during cross-orbit payload transfer. The payload is modeled by Euler–Bernoulli beam theory, and analysis shows that even small bending deformation of the payload can induce large attitude motion of the climber-payload assembly due to strong orbit-rigid–flexible coupling. To quantify this behavior, a closed-form expression is derived for the steady bending deformation of the payload under the gravity-gradient effect. Building on this analytical insight, a nonlinear compensation control torque is formulated to suppress attitude motion caused by rigid–flexible coupling without requiring impractically large control torques. To enhance control robustness, a super-twisting sliding mode control scheme is proposed by embedding the forward control law within a Lyapunov stability framework. This combined strategy eliminates residual dynamics and reduces the chattering inherent in sliding mode control while ensuring global attitude stability. Numerical simulations verify that the proposed strategy significantly reduces the attitude excursions of the climber-payload assembly while keeping the required control torques within the capacity of reaction wheels on the climber (rigid body). Overall, this work establishes a nonlinear dynamic framework for tethered transport systems with slender structure payloads and provides the first validated control solution enabling safe, stable, and efficient operation of partial space elevator transporting slender structure payloads.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 491-503"},"PeriodicalIF":3.4,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978441","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 : 2026-01-07DOI: 10.1016/j.actaastro.2026.01.018
Martin Sippel, Jascha Wilken, Ingrid Dietlein, Moritz Herberhold, Kevin Bergmann, Leonid Bussler
As soon as the SpaceX Starship & SuperHeavy launcher configuration is operationally available it likely will cause a fundamental shift to space transportation. In a first step, the paper provides a thorough technical analysis of Starship's estimated capabilities in its early operational phase, based on independent modeling with openly available data.
The main part of the paper is dedicated to the technical evaluation of European options for serving a roughly similar payload class above 20 Mg up to approaching 100 Mg in single launch to LEO. A launcher system analysis looks into Ariane 6 evolution options and explores the technical limits based on the assumption of expendable stages. A significantly better performance perspective can be achieved through a completely new architecture. In case of these new architecture launchers, all first stages are reusable and exclusively liquid cryogenic propellants are chosen. Fully reusable configurations have been addressed in the small ESA-funded PROTEIN-study for which some complementary concepts are summarized.
The different launcher options show a broad range in payload performance. As these diverse vehicles come with significantly different cost, the NRC and RC are modeled for reasonable European heavy-lift transportation scenarios.
The paper concludes with a comparative evaluation of main technical characteristics of the launch vehicle options and an indication of promising development roadmaps.
{"title":"Evaluating launcher options for Europe in a world of Starship","authors":"Martin Sippel, Jascha Wilken, Ingrid Dietlein, Moritz Herberhold, Kevin Bergmann, Leonid Bussler","doi":"10.1016/j.actaastro.2026.01.018","DOIUrl":"10.1016/j.actaastro.2026.01.018","url":null,"abstract":"<div><div>As soon as the SpaceX Starship & SuperHeavy launcher configuration is operationally available it likely will cause a fundamental shift to space transportation. In a first step, the paper provides a thorough technical analysis of Starship's estimated capabilities in its early operational phase, based on independent modeling with openly available data.</div><div>The main part of the paper is dedicated to the technical evaluation of European options for serving a roughly similar payload class above 20 Mg up to approaching 100 Mg in single launch to LEO. A launcher system analysis looks into Ariane 6 evolution options and explores the technical limits based on the assumption of expendable stages. A significantly better performance perspective can be achieved through a completely new architecture. In case of these new architecture launchers, all first stages are reusable and exclusively liquid cryogenic propellants are chosen. Fully reusable configurations have been addressed in the small ESA-funded PROTEIN-study for which some complementary concepts are summarized.</div><div>The different launcher options show a broad range in payload performance. As these diverse vehicles come with significantly different cost, the NRC and RC are modeled for reasonable European heavy-lift transportation scenarios.</div><div>The paper concludes with a comparative evaluation of main technical characteristics of the launch vehicle options and an indication of promising development roadmaps.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"241 ","pages":"Pages 455-472"},"PeriodicalIF":3.4,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979120","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 : 2026-01-07DOI: 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":"2026-01-07","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 : 2026-01-07DOI: 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":"2026-01-07","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}
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