Pub Date : 2026-01-23DOI: 10.1016/j.actaastro.2026.01.052
Jinah Lee, Chandeok Park
This research presents a Galerkin Lie group variational integrator on designed for analyzing the orbit–attitude coupled motions of spacecraft operating near small celestial bodies. Two primary objectives lie in constructing the proposed integrator: to preserve both the Lie group and Hamiltonian structures, and to achieve precise propagation comparable to conventional vector-based methods. This study analytically derives the partial derivatives of the rigid-body potential with respect to state variables and incorporates them into the discrete Lagrangian formulation to facilitate the integration process. The proposed integrator supports general gravity models of small celestial bodies. Example applications using both the point mass and spherical harmonics models are presented. Numerical simulations verify that the proposed integrator not only maintains geometric structure but also yields high accuracy in propagation, demonstrating its effectiveness for long-term simulations in the vicinity of small celestial bodies. For instance, the proposed integrator achieves an energy-conservation error on the order of % of the initial total energy, regardless of the initial state, whereas the error of the vector-based integrator varies over a wider range of %.
{"title":"Galerkin lie group variational integrators developed for orbit-attitude coupled dynamics near small celestial bodies","authors":"Jinah Lee, Chandeok Park","doi":"10.1016/j.actaastro.2026.01.052","DOIUrl":"10.1016/j.actaastro.2026.01.052","url":null,"abstract":"<div><div>This research presents a Galerkin Lie group variational integrator on <span><math><mrow><msup><mi>R</mi><mn>3</mn></msup><mo>×</mo><msup><mi>S</mi><mn>3</mn></msup></mrow></math></span> designed for analyzing the orbit–attitude coupled motions of spacecraft operating near small celestial bodies. Two primary objectives lie in constructing the proposed integrator: to preserve both the Lie group and Hamiltonian structures, and to achieve precise propagation comparable to conventional vector-based methods. This study analytically derives the partial derivatives of the rigid-body potential with respect to state variables and incorporates them into the discrete Lagrangian formulation to facilitate the integration process. The proposed integrator supports general gravity models of small celestial bodies. Example applications using both the point mass and spherical harmonics models are presented. Numerical simulations verify that the proposed integrator not only maintains geometric structure but also yields high accuracy in propagation, demonstrating its effectiveness for long-term simulations in the vicinity of small celestial bodies. For instance, the proposed integrator achieves an energy-conservation error on the order of <span><math><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup></mrow></math></span> % of the initial total energy, regardless of the initial state, whereas the error of the vector-based integrator varies over a wider range of <span><math><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math></span> %.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"243 ","pages":"Pages 220-236"},"PeriodicalIF":3.4,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033442","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 : 2026-01-22DOI: 10.1016/j.actaastro.2026.01.051
Zhongbao Yan , Chun Yin , Xuegang Huang , Jiuwen Cao , Yuanhao Zhang
The complex damage caused by hypervelocity impact poses significant challenges for spacecraft damage detection. This paper presents a novel method for detecting hypervelocity impact damage in spacecraft based on infrared nondestructive testing, which utilizes transient thermal response data and designs an adaptive classification model based on kernel density estimation to effectively distinguish different types of defect information. Additionally, the paper addresses the issue of extracting typical transient thermal responses from various defect types and constructs a multi-objective optimization function based on intraclass representativeness and interclass distinctiveness. The proposed multi-objective evolutionary optimization algorithm, combined with the -shape method, neural networks, and vertical distance measures, dynamically adjusts the weight vectors to optimize the distribution of solutions and balance convergence and diversity, resulting in higher quality typical transient thermal responses. Experimental results validate the effectiveness of the proposed method on real hypervelocity impact specimens, successfully obtaining defect images of different types.
{"title":"A multi-objective evolutionary optimization for infrared image reconstruction and typical thermal response selection in hypervelocity impact damage detection","authors":"Zhongbao Yan , Chun Yin , Xuegang Huang , Jiuwen Cao , Yuanhao Zhang","doi":"10.1016/j.actaastro.2026.01.051","DOIUrl":"10.1016/j.actaastro.2026.01.051","url":null,"abstract":"<div><div>The complex damage caused by hypervelocity impact poses significant challenges for spacecraft damage detection. This paper presents a novel method for detecting hypervelocity impact damage in spacecraft based on infrared nondestructive testing, which utilizes transient thermal response data and designs an adaptive classification model based on kernel density estimation to effectively distinguish different types of defect information. Additionally, the paper addresses the issue of extracting typical transient thermal responses from various defect types and constructs a multi-objective optimization function based on intraclass representativeness and interclass distinctiveness. The proposed multi-objective evolutionary optimization algorithm, combined with the <span><math><mi>α</mi></math></span>-shape method, neural networks, and vertical distance measures, dynamically adjusts the weight vectors to optimize the distribution of solutions and balance convergence and diversity, resulting in higher quality typical transient thermal responses. Experimental results validate the effectiveness of the proposed method on real hypervelocity impact specimens, successfully obtaining defect images of different types.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"243 ","pages":"Pages 46-60"},"PeriodicalIF":3.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033456","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 : 2026-01-22DOI: 10.1016/j.actaastro.2026.01.049
Carmen Pardini, Luciano Anselmo
Between 2010 and 2024, the risk posed by uncontrolled orbital re-entries of spacecraft, upper stages, and large debris to people on the ground and commercial aviation was assessed using realistic models for the number and casualty area of surviving fragments, as well as for the latitudinal distribution of population and air traffic. Each re-entered object was analyzed individually, taking into account its dry mass and actual orbital inclination. Furthermore, the effects of complete atmospheric demise were evaluated for objects with a re-entry dry mass of less than 300 kg. The nominal estimates obtained with the various approaches are expected to be affected by uncertainties of a factor of 2 or 3. Throughout the decade from 2010 to 2019, the risk levels remained relatively stable. However, from 2020 onward, there was a significant increase in risk, primarily due to the intensification of space activities. In 2024, the estimated collective casualty probability for people on the ground ranged between the nominal values of 5 % and 10 %, depending on the assumptions and models adopted. In the same year, the likelihood of a commercial aircraft being struck by re-entry debris capable of causing catastrophic failure was assessed to be between the nominal values of 3.7 × 10−5 and 1.5 × 10−4. This equates to an average of one aircraft impact every 27,000–6700 years, respectively. For passengers aboard commercial aircraft, the nominal collective casualty probability ranged from 0.44 % to 1.82 %. Although the overall re-entry risk remains relatively low, a notable upward trend was observed between 2019 and 2024. Specifically, the number of uncontrolled re-entries increased by a factor of 7, the cumulative re-entered mass increased by a factor of 3, the ground casualty probability rose by a factor of 3–4, and the casualty probability for commercial aircraft passengers increased by a factor of 3–6. This marked escalation highlights the urgent need for timely and effective mitigation strategies to prevent risks from exceeding thresholds deemed unacceptable from both operational and societal perspectives.
{"title":"The risk on the ground and in the airspace posed by uncontrolled re-entries: Should the growth observed in recent years be considered worrying?","authors":"Carmen Pardini, Luciano Anselmo","doi":"10.1016/j.actaastro.2026.01.049","DOIUrl":"10.1016/j.actaastro.2026.01.049","url":null,"abstract":"<div><div>Between 2010 and 2024, the risk posed by uncontrolled orbital re-entries of spacecraft, upper stages, and large debris to people on the ground and commercial aviation was assessed using realistic models for the number and casualty area of surviving fragments, as well as for the latitudinal distribution of population and air traffic. Each re-entered object was analyzed individually, taking into account its dry mass and actual orbital inclination. Furthermore, the effects of complete atmospheric demise were evaluated for objects with a re-entry dry mass of less than 300 kg. The nominal estimates obtained with the various approaches are expected to be affected by uncertainties of a factor of 2 or 3. Throughout the decade from 2010 to 2019, the risk levels remained relatively stable. However, from 2020 onward, there was a significant increase in risk, primarily due to the intensification of space activities. In 2024, the estimated collective casualty probability for people on the ground ranged between the nominal values of 5 % and 10 %, depending on the assumptions and models adopted. In the same year, the likelihood of a commercial aircraft being struck by re-entry debris capable of causing catastrophic failure was assessed to be between the nominal values of 3.7 × 10<sup>−5</sup> and 1.5 × 10<sup>−4</sup>. This equates to an average of one aircraft impact every 27,000–6700 years, respectively. For passengers aboard commercial aircraft, the nominal collective casualty probability ranged from 0.44 % to 1.82 %. Although the overall re-entry risk remains relatively low, a notable upward trend was observed between 2019 and 2024. Specifically, the number of uncontrolled re-entries increased by a factor of 7, the cumulative re-entered mass increased by a factor of 3, the ground casualty probability rose by a factor of 3–4, and the casualty probability for commercial aircraft passengers increased by a factor of 3–6. This marked escalation highlights the urgent need for timely and effective mitigation strategies to prevent risks from exceeding thresholds deemed unacceptable from both operational and societal perspectives.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"242 ","pages":"Pages 312-327"},"PeriodicalIF":3.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033944","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 : 2026-01-22DOI: 10.1016/j.actaastro.2026.01.050
M.J. Burchell, L.A. Alesbrook, M. van Ginneken, P.J. Wozniakiewicz
The growth in the number of satellites in Low Earth Orbit, coupled with the possibility of their catastrophic disruption, may lead to more orbital debris, which in turn has increased the risk of damage to spacecraft arising from impacts by small pieces of debris. There is thus an urgent need to monitor the small particle population in Low Earth Orbit, using a new generation of dust detectors. Various designs are in preparation, and several use the principle of observing particles via their impact penetration of thin films. Previously, most laboratory studies of penetration of thin films have used spherical impactors for ease. However, these are not representative of the shapes of orbital debris. Accordingly, here, impacts are reported at 5 km s−1, by various shaped projectiles (sizes typically 0.5–2 mm) on thin (12.5 μm thick) Kapton films. The shapes used were spheres, rods, cubes and platelets, and represent a selection of the shapes present in the orbital debris population that arises from catastrophic disruption of spacecraft. The size and shape of the holes in the Kapton arising from the impacts, are shown to reflect the size and cross-sectional area of an impactor as it passes through the film; even the presence of angular corners in the impactors can be seen in the holes. However, due to the variable aspect of an individual impactor presented to the film during an impact, identification of the exact 3-dimensional shape cannot be obtained from the 2-dimensional hole. Nevertheless, with minor exceptions it is possible to separate more spherical (i.e., natural dust) impactors from the other shapes (i.e. variously shaped anthropogenic debris).
低地球轨道卫星数量的增加，加上它们可能遭受灾难性破坏，可能导致更多的轨道碎片，这反过来又增加了小碎片撞击造成航天器损坏的风险。因此，迫切需要使用新一代的尘埃探测器来监测近地轨道上的小颗粒数量。各种设计正在准备中，其中一些利用了通过粒子对薄膜的冲击穿透来观察粒子的原理。以前，为了方便起见，大多数关于薄膜穿透的实验室研究都使用球形撞击器。然而，这些并不能代表轨道碎片的形状。因此，在这里，各种形状的弹丸（尺寸通常为0.5-2毫米）在薄（12.5 μm厚）Kapton薄膜上以5 km s - 1的速度撞击。所使用的形状有球体、棒状、立方体和血小板，这些形状代表了由于航天器灾难性破坏而产生的轨道碎片群中存在的一些形状。撞击产生的孔的大小和形状反映了撞击物穿过薄膜时的大小和横截面积；在孔中甚至可以看到撞击器中存在的棱角。然而，由于单个冲击体在冲击过程中呈现在薄膜上的可变方面，因此无法从二维孔中获得准确的三维形状。然而，除了少数例外，有可能将更球形（即天然尘埃）的撞击物与其他形状（即各种形状的人为碎片）分开。
{"title":"Hypervelocity perforation of thin films applicable to debris detection in Low Earth Orbit","authors":"M.J. Burchell, L.A. Alesbrook, M. van Ginneken, P.J. Wozniakiewicz","doi":"10.1016/j.actaastro.2026.01.050","DOIUrl":"10.1016/j.actaastro.2026.01.050","url":null,"abstract":"<div><div>The growth in the number of satellites in Low Earth Orbit, coupled with the possibility of their catastrophic disruption, may lead to more orbital debris, which in turn has increased the risk of damage to spacecraft arising from impacts by small pieces of debris. There is thus an urgent need to monitor the small particle population in Low Earth Orbit, using a new generation of dust detectors. Various designs are in preparation, and several use the principle of observing particles via their impact penetration of thin films. Previously, most laboratory studies of penetration of thin films have used spherical impactors for ease. However, these are not representative of the shapes of orbital debris. Accordingly, here, impacts are reported at 5 km s<sup>−1</sup>, by various shaped projectiles (sizes typically 0.5–2 mm) on thin (12.5 μm thick) Kapton films. The shapes used were spheres, rods, cubes and platelets, and represent a selection of the shapes present in the orbital debris population that arises from catastrophic disruption of spacecraft. The size and shape of the holes in the Kapton arising from the impacts, are shown to reflect the size and cross-sectional area of an impactor as it passes through the film; even the presence of angular corners in the impactors can be seen in the holes. However, due to the variable aspect of an individual impactor presented to the film during an impact, identification of the exact 3-dimensional shape cannot be obtained from the 2-dimensional hole. Nevertheless, with minor exceptions it is possible to separate more spherical (i.e., natural dust) impactors from the other shapes (i.e. variously shaped anthropogenic debris).</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"243 ","pages":"Pages 73-90"},"PeriodicalIF":3.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033457","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 : 2026-01-22DOI: 10.1016/j.actaastro.2026.01.029
Qiming Ren , Minghe Shan
Robotic In-Orbit Assembly (R-IOA) is a key technology for the construction of large-scale space infrastructure. A significant challenge in this field is the precise docking of modular components, particularly those with complex interfaces. To address this, safety must be considered at both the control and planning levels. At the control level, traditional compliant control strategies show poor adaptability to complex contact and often face challenges in explicitly enforcing physical limitations, such as joint position and torque bounds. Furthermore, while compliant control can effectively manage steady-state contact forces, it is fundamentally limited in mitigating the initial transient impact. This peak force is predominantly determined by the pre-impact velocity, a parameter dictated by the trajectory planner. Conventional planners, however, often generate dynamically infeasible trajectories using decoupled methods that violate the kinematic consistency of rigid-body motion, and they are generally limited in their ability to strictly enforce velocity constraints. To address these dual challenges through an integrated approach, this paper proposes a unified safety framework. This framework combines comprehensive enhancements at both the planning and control layers. At the planning level, a time-optimal trajectory generator operating on the SE(3) manifold produces motions that are dynamically feasible by construction. This ensures that velocity constraints are strictly enforced to proactively minimize impact forces and that the trajectory respects the natural kinematics of rigid-body motion. At the control level, we introduce a Hierarchical Quadratic Programming based Adaptive Controller (HQP-AC). It reformulates compliant interaction as a constrained optimization problem to guarantee the strict enforcement of all hardware safety limits while adaptively managing the steady-state interaction. The effectiveness of the proposed approach was demonstrated through simulations of a representative docking scenario. Compared to a classical impedance controller with decoupled trajectory planning, the proposed framework reduces peak axial contact forces by 49% and steady-state contact forces by 30%, and successfully prevents the catastrophic joint limit violations observed in the baseline method. Furthermore, it achieves a final lateral position error of 0.18 mm and an orientation error of 1.08°, representing a significant improvement in docking accuracy.
{"title":"A unified framework for compliant control and trajectory planning in robotic in-orbit assembly","authors":"Qiming Ren , Minghe Shan","doi":"10.1016/j.actaastro.2026.01.029","DOIUrl":"10.1016/j.actaastro.2026.01.029","url":null,"abstract":"<div><div>Robotic In-Orbit Assembly (R-IOA) is a key technology for the construction of large-scale space infrastructure. A significant challenge in this field is the precise docking of modular components, particularly those with complex interfaces. To address this, safety must be considered at both the control and planning levels. At the control level, traditional compliant control strategies show poor adaptability to complex contact and often face challenges in explicitly enforcing physical limitations, such as joint position and torque bounds. Furthermore, while compliant control can effectively manage steady-state contact forces, it is fundamentally limited in mitigating the initial transient impact. This peak force is predominantly determined by the pre-impact velocity, a parameter dictated by the trajectory planner. Conventional planners, however, often generate dynamically infeasible trajectories using decoupled methods that violate the kinematic consistency of rigid-body motion, and they are generally limited in their ability to strictly enforce velocity constraints. To address these dual challenges through an integrated approach, this paper proposes a unified safety framework. This framework combines comprehensive enhancements at both the planning and control layers. At the planning level, a time-optimal trajectory generator operating on the SE(3) manifold produces motions that are dynamically feasible by construction. This ensures that velocity constraints are strictly enforced to proactively minimize impact forces and that the trajectory respects the natural kinematics of rigid-body motion. At the control level, we introduce a Hierarchical Quadratic Programming based Adaptive Controller (HQP-AC). It reformulates compliant interaction as a constrained optimization problem to guarantee the strict enforcement of all hardware safety limits while adaptively managing the steady-state interaction. The effectiveness of the proposed approach was demonstrated through simulations of a representative docking scenario. Compared to a classical impedance controller with decoupled trajectory planning, the proposed framework reduces peak axial contact forces by 49% and steady-state contact forces by 30%, and successfully prevents the catastrophic joint limit violations observed in the baseline method. Furthermore, it achieves a final lateral position error of 0.18<!--> <!-->mm and an orientation error of 1.08°, representing a significant improvement in docking accuracy.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"243 ","pages":"Pages 32-45"},"PeriodicalIF":3.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033440","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 : 2026-01-22DOI: 10.1016/j.actaastro.2025.12.053
Michael Herman, Olivia J. Pinon Fischer, Dimitri N. Mavris
Attitude sensors determine the spacecraft attitude through the sensing of an astronomical object, field or other phenomena. The Sun and fixed stars are the two primary astronomical sensing objects. Attitude sensors are critical components for the survival and knowledge improvement of spacecraft. Of these, sun sensors are one of the most common and important sensors for small satellite attitude determination. The sun sensor measures the Sun vector in spacecraft coordinates. The sun sensor calibration process is particularly difficult due to the complex nature of the uncertainties involved. The uncertainties are small, difficult to observe, and vary spatio-temporally over the lifecycle of the sensor. In addition, the sensors are affected by numerous sources of uncertainties, including manufacturing, electrical, environmental, and interference sources. This motivates the development of advanced calibration algorithms to minimize uncertainty over the sensor lifecycle and improve accuracy. Although modeling and calibration techniques for sun sensors have been explored extensively in the literature over the past two decades, there is currently no resource that consolidates and systematically reviews this body of work. The present review proposes a systematic mapping of sun sensor modeling and calibration algorithms across a breadth of sensor configurations. It specifically provides a comprehensive survey of each methodology, along with an analysis of research gaps and recommendations for future directions in sun sensor modeling and calibration techniques.
{"title":"Sun sensor calibration algorithms: A systematic mapping and survey","authors":"Michael Herman, Olivia J. Pinon Fischer, Dimitri N. Mavris","doi":"10.1016/j.actaastro.2025.12.053","DOIUrl":"10.1016/j.actaastro.2025.12.053","url":null,"abstract":"<div><div>Attitude sensors determine the spacecraft attitude through the sensing of an astronomical object, field or other phenomena. The Sun and fixed stars are the two primary astronomical sensing objects. Attitude sensors are critical components for the survival and knowledge improvement of spacecraft. Of these, sun sensors are one of the most common and important sensors for small satellite attitude determination. The sun sensor measures the Sun vector in spacecraft coordinates. The sun sensor calibration process is particularly difficult due to the complex nature of the uncertainties involved. The uncertainties are small, difficult to observe, and vary spatio-temporally over the lifecycle of the sensor. In addition, the sensors are affected by numerous sources of uncertainties, including manufacturing, electrical, environmental, and interference sources. This motivates the development of advanced calibration algorithms to minimize uncertainty over the sensor lifecycle and improve accuracy. Although modeling and calibration techniques for sun sensors have been explored extensively in the literature over the past two decades, there is currently no resource that consolidates and systematically reviews this body of work. The present review proposes a systematic mapping of sun sensor modeling and calibration algorithms across a breadth of sensor configurations. It specifically provides a comprehensive survey of each methodology, along with an analysis of research gaps and recommendations for future directions in sun sensor modeling and calibration techniques.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"243 ","pages":"Pages 112-148"},"PeriodicalIF":3.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033458","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 : 2026-01-21DOI: 10.1016/j.actaastro.2026.01.048
Yaqiang Wei , Xiaoxiang Liu , Bowen Zhan , Hao Wen , Ti Chen
To conduct deep-space exploration and high-precision Earth observation, there is an urgent need for on-orbit construction of ultra-large optical systems. Space robotics technology, with its advantages of high operational reliability and strong task extensibility, has emerged as a hot topic for such missions. In the paper, the progress and development trends in space robots for on-orbit construction are presented in a detailed review, organized around four topics: system design, on-orbit perception, motion planning, and compliant control. Ultra-large optical systems are characterized by the large scale and significant flexibility, which places higher challenges on space robotics technology: Precise switching among multiple mobility modes and multi-arm reconfiguration, distributed multimodal high-accuracy perception under harsh conditions, motion planning in confined workspaces and high-fidelity sequence verification, and compliant multi-point assembly under complex geometric interference and low-frequency vibration. Furthermore, engineering challenges and the future outlook of space robotics technology for on-orbit construction of ultra-large optical systems are summarized. This review aims to accelerate theoretical research, ground testing, and on-orbit demonstration for the construction of ultra-large optical systems.
{"title":"Review of space robotics technology for on-orbit construction of ultra-large optical systems","authors":"Yaqiang Wei , Xiaoxiang Liu , Bowen Zhan , Hao Wen , Ti Chen","doi":"10.1016/j.actaastro.2026.01.048","DOIUrl":"10.1016/j.actaastro.2026.01.048","url":null,"abstract":"<div><div>To conduct deep-space exploration and high-precision Earth observation, there is an urgent need for on-orbit construction of ultra-large optical systems. Space robotics technology, with its advantages of high operational reliability and strong task extensibility, has emerged as a hot topic for such missions. In the paper, the progress and development trends in space robots for on-orbit construction are presented in a detailed review, organized around four topics: system design, on-orbit perception, motion planning, and compliant control. Ultra-large optical systems are characterized by the large scale and significant flexibility, which places higher challenges on space robotics technology: Precise switching among multiple mobility modes and multi-arm reconfiguration, distributed multimodal high-accuracy perception under harsh conditions, motion planning in confined workspaces and high-fidelity sequence verification, and compliant multi-point assembly under complex geometric interference and low-frequency vibration. Furthermore, engineering challenges and the future outlook of space robotics technology for on-orbit construction of ultra-large optical systems are summarized. This review aims to accelerate theoretical research, ground testing, and on-orbit demonstration for the construction of ultra-large optical systems.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"242 ","pages":"Pages 141-157"},"PeriodicalIF":3.4,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014248","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 : 2026-01-21DOI: 10.1016/j.actaastro.2026.01.047
Xin Lin , Gang Zhang , Rafael Vazquez
This paper presents a semi-analytical method for propagating orbital states under continuous thrust in nonlinear motion relative to collinear libration points within the circular restricted three-body problem. The proposed approach jointly approximates higher-order nonlinear dynamics and thrust acceleration using a truncated Fourier series with respect to time, thereby transforming the governing equation into a linear-like form. This transformation enables analytical state propagation through the series expansion coefficients, reducing the problem to the determination of these coefficients via a nonlinear least-squares method. Building upon this framework, a fuel-optimal transfer method for libration point orbits is developed and reformulated as a sequential second-order cone programming problem, with the energy-optimal solution employed as the initial guess. Numerical examples in the Sun–Earth system are provided to demonstrate the accuracy of the proposed state propagation method and to validate the effectiveness of the optimal transfer approach for Halo orbits.
{"title":"Nonlinear continuous-thrust state propagation and its application in optimal orbital transfers around collinear libration points","authors":"Xin Lin , Gang Zhang , Rafael Vazquez","doi":"10.1016/j.actaastro.2026.01.047","DOIUrl":"10.1016/j.actaastro.2026.01.047","url":null,"abstract":"<div><div>This paper presents a semi-analytical method for propagating orbital states under continuous thrust in nonlinear motion relative to collinear libration points within the circular restricted three-body problem. The proposed approach jointly approximates higher-order nonlinear dynamics and thrust acceleration using a truncated Fourier series with respect to time, thereby transforming the governing equation into a linear-like form. This transformation enables analytical state propagation through the series expansion coefficients, reducing the problem to the determination of these coefficients via a nonlinear least-squares method. Building upon this framework, a fuel-optimal transfer method for libration point orbits is developed and reformulated as a sequential second-order cone programming problem, with the energy-optimal solution employed as the initial guess. Numerical examples in the Sun–Earth system are provided to demonstrate the accuracy of the proposed state propagation method and to validate the effectiveness of the optimal transfer approach for Halo orbits.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"242 ","pages":"Pages 264-276"},"PeriodicalIF":3.4,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014249","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 : 2026-01-20DOI: 10.1016/j.actaastro.2026.01.034
Daniela de Paulis , Claudia Mignone , Bettina Forget , Irene Fabbri , Gianfranco De Vito , Franck Marchis
On May 24, 2023, the European Space Agency's Trace Gas Orbiter transmitted a simulated extraterrestrial message to Earth, received by telescopes in the United States and Italy. This event was part of the interdisciplinary project A Sign in Space, developed over four years in collaboration with multiple research institutions. The project simulates a scenario where scientists release a potential extraterrestrial signal to the public for decoding and interpretation. Following the data release, an international community on the Discord platform engaged in extensive decoding efforts, generating thousands of interpretations and widespread social media discussion. A Sign in Space reached over a hundred million people globally through media coverage and online channels, demonstrating significant public interest and engagement. The project highlights the importance of public engagement in scientific research and the potential for interdisciplinary collaborations to create meaningful dialogues around complex topics like the search for extraterrestrial life. By fostering a sense of global community and shared exploration, A Sign in Space offers a model for future interdisciplinary projects that seek to inspire and engage diverse audiences. This paper discusses some of the challenges encountered in the global outreach of the project, presenting lessons learnt that could be useful for participatory science around the theme of extraterrestrial communication.
2023年5月24日，欧洲航天局的微量气体轨道飞行器向地球发送了一条模拟的地外信息，美国和意大利的望远镜接收到了这条信息。该活动是与多个研究机构合作开发的跨学科项目A Sign in Space的一部分。该项目模拟了一个场景，科学家向公众发布一个潜在的外星信号，让他们解码和解释。数据发布后，Discord平台上的一个国际社区进行了广泛的解码工作，产生了数千种解释和广泛的社交媒体讨论。通过媒体报道和网络渠道，“空间标识”活动在全球范围内吸引了超过1亿人，显示出极大的公众兴趣和参与度。该项目强调了公众参与科学研究的重要性，以及跨学科合作的潜力，以围绕寻找外星生命等复杂话题开展有意义的对话。通过培养全球社区意识和共同探索，a Sign in Space为未来的跨学科项目提供了一个模式，旨在激励和吸引不同的受众。本文讨论了该项目在全球推广中遇到的一些挑战，提出了可能对围绕地外通信主题的参与性科学有用的经验教训。
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