This work validates lumped-parameter models and cable-based models for nets against data from a parabolic flight experiment. The capabilities of a simulator based in Vortex Studio, a multibody dynamics simulation framework, are expanded by introducing i) a lumped-parameter model of the net with lumped masses placed along the threads and ii) a flexible-cable-based model, both of which enable collision detection with thin bodies. An experimental scenario is recreated in simulation, and the deployment and capture phases are analyzed. Good agreement with experiments is observed in both phases, although with differences primarily due to imperfect knowledge of experimental initial conditions. It is demonstrated that both a lumped-parameter model with inner nodes and a cable-based model can enable the detection of collisions between the net and thin geometries of the target. While both models improve notably capture realism compared to a lumped parameter model with no inner nodes, the cable-based model is found to be most computationally efficient. The effect of modeling thread-to-thread collisions (i.e., collisions among parts of the net) is analyzed and determined to be negligible during deployment and initial target wrapping. The results of this work validate the models and increase the confidence in the practicality of this simulator as a tool for research on net-based capture of debris. A cable-based model is validated for the first time in the literature.
{"title":"Validation of Models for Net Deployment and Capture Simulation with Experimental Data","authors":"Achira Boonrath, E. M. Botta","doi":"10.2514/1.a35798","DOIUrl":"https://doi.org/10.2514/1.a35798","url":null,"abstract":"This work validates lumped-parameter models and cable-based models for nets against data from a parabolic flight experiment. The capabilities of a simulator based in Vortex Studio, a multibody dynamics simulation framework, are expanded by introducing i) a lumped-parameter model of the net with lumped masses placed along the threads and ii) a flexible-cable-based model, both of which enable collision detection with thin bodies. An experimental scenario is recreated in simulation, and the deployment and capture phases are analyzed. Good agreement with experiments is observed in both phases, although with differences primarily due to imperfect knowledge of experimental initial conditions. It is demonstrated that both a lumped-parameter model with inner nodes and a cable-based model can enable the detection of collisions between the net and thin geometries of the target. While both models improve notably capture realism compared to a lumped parameter model with no inner nodes, the cable-based model is found to be most computationally efficient. The effect of modeling thread-to-thread collisions (i.e., collisions among parts of the net) is analyzed and determined to be negligible during deployment and initial target wrapping. The results of this work validate the models and increase the confidence in the practicality of this simulator as a tool for research on net-based capture of debris. A cable-based model is validated for the first time in the literature.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41660788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chloe Downs, A. Prasad, Bradford Robertson, D. Mavris
As space exploration moves toward long-duration, sustainable campaigns, operations such as in-space rendezvous, multiple launches, and in-space rendezvous or In-Situ Resource Utilization plants complicate campaign planning. The field of spaceflight logistics has been developed to perform the logistical planning for these new campaigns in an automated manner. Though previous tools have included aggregated vehicle concepts consisting of multiple vehicles, they have key limitations that may not be able to assess campaigns with more complex vehicle architectures and mission operations. This works aims to address these limitations by formulating a method to include independently operating vehicles that can also operate as an element within a larger stack across various different mission segments. Because of the use of the path-arc formulation, the optimizer has the flexibility to decide to use the independent vehicle stages independently, or within a stack. To prove the usefulness of this formulation, the methodology will be applied to a sample case that uses some of these aggregated space vehicles. In particular, a case study of a government reference Human Landing System mission will be used due to its inclusion of aggregated space vehicles.
{"title":"Spaceflight Logistics Approach to Modeling Aggregated Vehicle Concepts","authors":"Chloe Downs, A. Prasad, Bradford Robertson, D. Mavris","doi":"10.2514/1.a35724","DOIUrl":"https://doi.org/10.2514/1.a35724","url":null,"abstract":"As space exploration moves toward long-duration, sustainable campaigns, operations such as in-space rendezvous, multiple launches, and in-space rendezvous or In-Situ Resource Utilization plants complicate campaign planning. The field of spaceflight logistics has been developed to perform the logistical planning for these new campaigns in an automated manner. Though previous tools have included aggregated vehicle concepts consisting of multiple vehicles, they have key limitations that may not be able to assess campaigns with more complex vehicle architectures and mission operations. This works aims to address these limitations by formulating a method to include independently operating vehicles that can also operate as an element within a larger stack across various different mission segments. Because of the use of the path-arc formulation, the optimizer has the flexibility to decide to use the independent vehicle stages independently, or within a stack. To prove the usefulness of this formulation, the methodology will be applied to a sample case that uses some of these aggregated space vehicles. In particular, a case study of a government reference Human Landing System mission will be used due to its inclusion of aggregated space vehicles.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46417415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Aerodynamic Data to Design an Active Thermal Protection System for SpaceLiner 7-1","authors":"G. Zuppardi, G. Mongelluzzo","doi":"10.2514/1.a35665","DOIUrl":"https://doi.org/10.2514/1.a35665","url":null,"abstract":"","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49505469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reusable composite cryogenic tanks may be used in next-generation space launch systems due to their several benefits, such as increased specific strength, tailorability, and low coefficient of thermal expansion. However, transverse microcracks within composites due to thermal stresses and barely visible impact damage can cause cryogenic fuel to leak through the walls of the tank. The objective of the present study is to evaluate the gas permeability of impacted and thermally cycled composites and correlate it to their postimpact residual strength. Cross-ply carbon/epoxy composites ([Formula: see text]) fabricated from unidirectional prepregs were subjected to 20 cryogenic cycles from ambient to cryogenic temperatures ([Formula: see text]). Barely visible impact damage at two different impact velocities ([Formula: see text] and [Formula: see text]) was imparted to the specimens at room and cryogenic temperatures before and after cryogenic cycling. The composites’ gas permeability, residual flexural strength, and absorbed energy were measured and correlated. Composite specimens subjected to impact at room temperature had higher gas permeability and absorbed energy with lower residual flexural strength. A linear relationship was observed between gas permeability, absorbed energy, and postimpact flexural strength. Two linear models to predict gas permeability with absorbed energy and flexural strength as variables have been presented for impacted and cryogenically cycled specimens with an [Formula: see text] value of at least 96%.
{"title":"Gas Permeability and Flexural Strength of Impacted Composites for Cryogenic Propellant Tanks","authors":"Shuvam Saha, R. Sullivan","doi":"10.2514/1.a35703","DOIUrl":"https://doi.org/10.2514/1.a35703","url":null,"abstract":"Reusable composite cryogenic tanks may be used in next-generation space launch systems due to their several benefits, such as increased specific strength, tailorability, and low coefficient of thermal expansion. However, transverse microcracks within composites due to thermal stresses and barely visible impact damage can cause cryogenic fuel to leak through the walls of the tank. The objective of the present study is to evaluate the gas permeability of impacted and thermally cycled composites and correlate it to their postimpact residual strength. Cross-ply carbon/epoxy composites ([Formula: see text]) fabricated from unidirectional prepregs were subjected to 20 cryogenic cycles from ambient to cryogenic temperatures ([Formula: see text]). Barely visible impact damage at two different impact velocities ([Formula: see text] and [Formula: see text]) was imparted to the specimens at room and cryogenic temperatures before and after cryogenic cycling. The composites’ gas permeability, residual flexural strength, and absorbed energy were measured and correlated. Composite specimens subjected to impact at room temperature had higher gas permeability and absorbed energy with lower residual flexural strength. A linear relationship was observed between gas permeability, absorbed energy, and postimpact flexural strength. Two linear models to predict gas permeability with absorbed energy and flexural strength as variables have been presented for impacted and cryogenically cycled specimens with an [Formula: see text] value of at least 96%.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48279509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Zander, D. Buttsworth, Byrenn Birch, Allan Payne
The reentry trajectory of the Hayabusa2 capsule has been measured using a single video stream captured during the Australian Airborne Observation of the Hayabusa2 capsule. A new analysis methodology was required, and developed, to enable the trajectory to be determined from a single viewpoint. The method developed used the star-field background visible in the video stream, combined with the aircraft Global Positioning System data, to establish lines of sight along which the capsule was measured in time. A set of common sense criteria including altitude and velocity limits were then used to exclude impossible trajectories. The remaining trajectories were then examined and evaluated using a least-squares fitting routine to analyze candidate ballistic trajectories. The trajectories were ranked based on the fit parameter, enabling the determination of the single most likely trajectory and a family of most probable trajectories. The most probable Hayabusa2 capsule trajectory inferred from the measurements passed 10 km west of Coober Pedy and traveled at a heading of 150 deg. Evaluation of other highly probable trajectories showed they all passed Coober Pedy at a similar distance; however, they tended toward a slightly higher heading, approaching 155 deg. The distance between the measurement aircraft and the capsule remained relatively constant at approximately 180 km throughout the measurement period. This work demonstrates a new method for determining the trajectory of an object measured with a star-field background. Importantly, we have used this to establish the Hayabusa2 reentry capsule trajectory, and hence the distance from our aircraft, which will allow the detailed analysis of our spectral data.
{"title":"Trajectory Analysis of the Hayabusa2 Capsule from a Single Airborne Observation","authors":"F. Zander, D. Buttsworth, Byrenn Birch, Allan Payne","doi":"10.2514/1.a35719","DOIUrl":"https://doi.org/10.2514/1.a35719","url":null,"abstract":"The reentry trajectory of the Hayabusa2 capsule has been measured using a single video stream captured during the Australian Airborne Observation of the Hayabusa2 capsule. A new analysis methodology was required, and developed, to enable the trajectory to be determined from a single viewpoint. The method developed used the star-field background visible in the video stream, combined with the aircraft Global Positioning System data, to establish lines of sight along which the capsule was measured in time. A set of common sense criteria including altitude and velocity limits were then used to exclude impossible trajectories. The remaining trajectories were then examined and evaluated using a least-squares fitting routine to analyze candidate ballistic trajectories. The trajectories were ranked based on the fit parameter, enabling the determination of the single most likely trajectory and a family of most probable trajectories. The most probable Hayabusa2 capsule trajectory inferred from the measurements passed 10 km west of Coober Pedy and traveled at a heading of 150 deg. Evaluation of other highly probable trajectories showed they all passed Coober Pedy at a similar distance; however, they tended toward a slightly higher heading, approaching 155 deg. The distance between the measurement aircraft and the capsule remained relatively constant at approximately 180 km throughout the measurement period. This work demonstrates a new method for determining the trajectory of an object measured with a star-field background. Importantly, we have used this to establish the Hayabusa2 reentry capsule trajectory, and hence the distance from our aircraft, which will allow the detailed analysis of our spectral data.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43696933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ceramic thermal protection system (TPS) is bonded to the skin of a hypersonic vehicle through a strain isolation pad, and the separation of the TPS will affect the safety of the vehicle. In this paper, the aeroheating of the separation zone for the ceramic TPS is studied and compared with that of the intact TPS. The intact TPS mainly considers the aeroheating of the gap. The heat flux increases sharply in both the gap and separation zone, especially on the windward wall. The difference of peak heat flux between the windward and leeward walls in the separation zone is much larger than that in the gap, and the heat flux away from the gap and separation zone gradually returns to the normal heat flux of the TPS. The heat flux in the gap only exists in the small zone of the upper part, whereas that in the separation zone is widely distributed on the side walls. The heat flux on the bottom of the gap approaches zero, whereas that of the separation zone is high in the middle and low at ends, and the heat flux in the middle reaches 55% of the normal heat flux of the TPS. In addition, an analysis of influencing factors is conducted.
{"title":"Thermal Control Investigations on Separation Zone of Ceramic Thermal Protection System","authors":"Jie Huang, Zhen Dai","doi":"10.2514/1.a35612","DOIUrl":"https://doi.org/10.2514/1.a35612","url":null,"abstract":"Ceramic thermal protection system (TPS) is bonded to the skin of a hypersonic vehicle through a strain isolation pad, and the separation of the TPS will affect the safety of the vehicle. In this paper, the aeroheating of the separation zone for the ceramic TPS is studied and compared with that of the intact TPS. The intact TPS mainly considers the aeroheating of the gap. The heat flux increases sharply in both the gap and separation zone, especially on the windward wall. The difference of peak heat flux between the windward and leeward walls in the separation zone is much larger than that in the gap, and the heat flux away from the gap and separation zone gradually returns to the normal heat flux of the TPS. The heat flux in the gap only exists in the small zone of the upper part, whereas that in the separation zone is widely distributed on the side walls. The heat flux on the bottom of the gap approaches zero, whereas that of the separation zone is high in the middle and low at ends, and the heat flux in the middle reaches 55% of the normal heat flux of the TPS. In addition, an analysis of influencing factors is conducted.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46248639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lorenzo Federici, A. Scorsoglio, Alessandro Zavoli, R. Furfaro
This paper investigates the use of reinforcement learning for the fuel-optimal guidance of a spacecraft during a time-free low-thrust transfer between two libration point orbits in the cislunar environment. To this aim, a deep neural network is trained via proximal policy optimization to map any spacecraft state to the optimal control action. A general-purpose reward is used to guide the network toward a fuel-optimal control law, regardless of the specific pair of libration orbits considered and without the use of any ad hoc reward shaping technique. Eventually, the learned control policies are compared with the optimal solutions provided by a direct method in two different mission scenarios, and Monte Carlo simulations are used to assess the policies’ robustness to navigation uncertainties.
{"title":"Autonomous Guidance Between Quasiperiodic Orbits in Cislunar Space via Deep Reinforcement Learning","authors":"Lorenzo Federici, A. Scorsoglio, Alessandro Zavoli, R. Furfaro","doi":"10.2514/1.a35747","DOIUrl":"https://doi.org/10.2514/1.a35747","url":null,"abstract":"This paper investigates the use of reinforcement learning for the fuel-optimal guidance of a spacecraft during a time-free low-thrust transfer between two libration point orbits in the cislunar environment. To this aim, a deep neural network is trained via proximal policy optimization to map any spacecraft state to the optimal control action. A general-purpose reward is used to guide the network toward a fuel-optimal control law, regardless of the specific pair of libration orbits considered and without the use of any ad hoc reward shaping technique. Eventually, the learned control policies are compared with the optimal solutions provided by a direct method in two different mission scenarios, and Monte Carlo simulations are used to assess the policies’ robustness to navigation uncertainties.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45352530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During the vertical descent and landing of a launcher first stage with the aid of retropropulsion, commonly two main propulsive deceleration maneuvers are performed: the reentry burn in high altitudes at hypersonic to supersonic speeds and the landing burn shortly before touchdown at transonic to subsonic speeds. In the frame of the EU-funded H2020 project Retro Propulsion Assisted Landing Technologies (RETALT), the unsteady aerodynamics of those retropropulsion phases were studied. This paper presents results of experiments performed in the Hypersonic Wind Tunnel Cologne on the hypersonic reentry burn. The exhaust plume was simulated with pressurized air. Proper orthogonal decomposition was performed on high-speed schlieren videos, and spectral analyses of the time histories of the resulting modes were compared to the frequency content found in high-frequency pressure measurements. Dominant frequencies were found in the proper orthogonal decomposition modes for one and for three active engines. In the pressure measurements, dominant frequencies could only be observed for three active engines. The normalized pressure fluctuations are in the range of 0.002–0.012. Additionally, a good scaling of the pressures on the base area and in the wake of the configuration with the total pressure downstream of the bow shock could be confirmed, in the sense that the ratio of the local surface pressure to the total pressure downstream of the bow shock match for varying freestream Mach numbers.
{"title":"Unsteady Aerodynamics of the Retropropulsion Reentry Burn of Vertically Landing Launchers","authors":"A. Marwege, A. Gülhan","doi":"10.2514/1.a35647","DOIUrl":"https://doi.org/10.2514/1.a35647","url":null,"abstract":"During the vertical descent and landing of a launcher first stage with the aid of retropropulsion, commonly two main propulsive deceleration maneuvers are performed: the reentry burn in high altitudes at hypersonic to supersonic speeds and the landing burn shortly before touchdown at transonic to subsonic speeds. In the frame of the EU-funded H2020 project Retro Propulsion Assisted Landing Technologies (RETALT), the unsteady aerodynamics of those retropropulsion phases were studied. This paper presents results of experiments performed in the Hypersonic Wind Tunnel Cologne on the hypersonic reentry burn. The exhaust plume was simulated with pressurized air. Proper orthogonal decomposition was performed on high-speed schlieren videos, and spectral analyses of the time histories of the resulting modes were compared to the frequency content found in high-frequency pressure measurements. Dominant frequencies were found in the proper orthogonal decomposition modes for one and for three active engines. In the pressure measurements, dominant frequencies could only be observed for three active engines. The normalized pressure fluctuations are in the range of 0.002–0.012. Additionally, a good scaling of the pressures on the base area and in the wake of the configuration with the total pressure downstream of the bow shock could be confirmed, in the sense that the ratio of the local surface pressure to the total pressure downstream of the bow shock match for varying freestream Mach numbers.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44318558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The simultaneous interception of multiple exo-atmospheric threat targets can leave no buffer time for the targets and greatly reduces targets’ penetration probability. This paper proposes centralized and decentralized two midcourse guidance methods to solve the coordinated interception of multiple exo-atmospheric targets. First, the free-time cooperative interception problem minimizing the total impulses is established, where the nonlinear dynamics of the interceptors and targets, the initial impulse constraints, and the terminal interception constraints are considered. Second, the necessary conditions for the optimal cooperative interception problem are derived and then approximated using higher-order Taylor expansions, which result in a series of analytical nonlinear equations. Then, the semi-analytical centralized guidance mode is designed to achieve simultaneous interception of targets by directly solving the analytical nonlinear equations. To improve computational efficiency, the decentralized cooperative guidance mode is further proposed by using the developed iterative freezing trajectory method, where each interceptor uses information from other interceptors in the previous iteration for prediction and distributed computation. Numerical examples verify the effectiveness and robustness of the proposed two guidance methods. Results show that the computational efficiency of the decentralized guidance mode is more efficient compared with the centralized midcourse guidance mode.
{"title":"Semi-Analytical Midcourse Guidance for Coordinated Interception of Multiple Exo-Atmospheric Targets","authors":"Guoxu Zhang, Bo Pang, Changxuan Wen, Xun Song","doi":"10.2514/1.a35659","DOIUrl":"https://doi.org/10.2514/1.a35659","url":null,"abstract":"The simultaneous interception of multiple exo-atmospheric threat targets can leave no buffer time for the targets and greatly reduces targets’ penetration probability. This paper proposes centralized and decentralized two midcourse guidance methods to solve the coordinated interception of multiple exo-atmospheric targets. First, the free-time cooperative interception problem minimizing the total impulses is established, where the nonlinear dynamics of the interceptors and targets, the initial impulse constraints, and the terminal interception constraints are considered. Second, the necessary conditions for the optimal cooperative interception problem are derived and then approximated using higher-order Taylor expansions, which result in a series of analytical nonlinear equations. Then, the semi-analytical centralized guidance mode is designed to achieve simultaneous interception of targets by directly solving the analytical nonlinear equations. To improve computational efficiency, the decentralized cooperative guidance mode is further proposed by using the developed iterative freezing trajectory method, where each interceptor uses information from other interceptors in the previous iteration for prediction and distributed computation. Numerical examples verify the effectiveness and robustness of the proposed two guidance methods. Results show that the computational efficiency of the decentralized guidance mode is more efficient compared with the centralized midcourse guidance mode.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44989084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The inclusion of operational sparing policies in early system definition can ensure that spares’ allocations can optimally meet desired system reliabilities consistent with the planned maintenance of a crewed vehicle. This approach is critical for long-duration crewed missions where mass allocations are constrained and lack of safe abort contingencies limit options in the event of significant system degradation, especially in the environmental control and life support systems. This paper presents an analytical model for analyzing and optimizing sparing policies as part of an overall evaluation of the probability of sufficiency for a system configuration. The repair transition parameters are varied to change the state visitation probabilities that drive a change in the probability of sufficiency observed for a given mass allocation. These parameters are optimized using a particle swarm optimizer to identify the preferred strategy for a desired allocation mass.
{"title":"Analytical Model for Sparing Policy Analysis and Optimization for Space Habitat Operations","authors":"Andrew J. Maxwell, K. Ho","doi":"10.2514/1.a35679","DOIUrl":"https://doi.org/10.2514/1.a35679","url":null,"abstract":"The inclusion of operational sparing policies in early system definition can ensure that spares’ allocations can optimally meet desired system reliabilities consistent with the planned maintenance of a crewed vehicle. This approach is critical for long-duration crewed missions where mass allocations are constrained and lack of safe abort contingencies limit options in the event of significant system degradation, especially in the environmental control and life support systems. This paper presents an analytical model for analyzing and optimizing sparing policies as part of an overall evaluation of the probability of sufficiency for a system configuration. The repair transition parameters are varied to change the state visitation probabilities that drive a change in the probability of sufficiency observed for a given mass allocation. These parameters are optimized using a particle swarm optimizer to identify the preferred strategy for a desired allocation mass.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45970600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：