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Volume 12
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Aerospace, Volume 12, Issue 2 (February 2025) – 47 articles

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13 pages, 604 KiB  
Article
Multi-Objective Airport Slot Allocation with Demand-Side Fairness Considerations
by Ruoshi Yang, Meilong Le and Qiangzhe Wang
Aerospace 2025, 12(2), 119; https://doi.org/10.3390/aerospace12020119 (registering DOI) - 3 Feb 2025
Abstract
Airport slot allocation is a key short-term solution to address airport capacity constraints, and it has long been a focus of research in the field of air traffic management. The existing studies primarily consider constraints such as airport capacity and flight operations, optimizing [...] Read more.
Airport slot allocation is a key short-term solution to address airport capacity constraints, and it has long been a focus of research in the field of air traffic management. The existing studies primarily consider constraints such as airport capacity and flight operations, optimizing the slot allocation of arrival and departure flights to maximize the utilization of airport resources. This study proposes an airline fairness index based on a demand-side value system and addresses the problem of flight slot allocation by developing a tri-objective model. The model simultaneously considers the maximum slot deviation, total slot deviation, and airline fairness. Additionally, dynamic capacity constraints using rolling time windows and constraints on slot migration during peak periods are incorporated. The ε-constraint method is employed in conjunction with a large-neighborhood search heuristic to solve a two-stage optimization process, yielding an efficient allocation scheme. The experimental results show that the introduction of rolling capacity constraints effectively resolves the issue of continuous overcapacity that arises when only a fixed capacity is considered. Additionally, the proposed airline fairness index, based on a demand-side value system, can significantly improve fairness during the slot allocation process. By sacrificing at most 16% of the total displacement, it is possible to reduce the unfairness index by nearly 80%. Full article
(This article belongs to the Special Issue Future Airspace and Air Traffic Management Design)
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24 pages, 3589 KiB  
Article
Methods for Analyzing Avionics Reliability Reflecting Atmospheric Radiation in the Preliminary Development Phase: An Integrated Failure Rate Analysis
by Dongmin Lee and Jongwhoa Na
Aerospace 2025, 12(2), 118; https://doi.org/10.3390/aerospace12020118 - 3 Feb 2025
Viewed by 99
Abstract
Abstract: Advances in deep submicron semiconductor technology have increased the significance of studying soft errors caused by atmospheric radiation in avionics systems. Atmospheric radiation particles, such as protons and neutrons, can induce Single Event Upsets (SEUs) in sensitive electronic components, leading to system [...] Read more.
Abstract: Advances in deep submicron semiconductor technology have increased the significance of studying soft errors caused by atmospheric radiation in avionics systems. Atmospheric radiation particles, such as protons and neutrons, can induce Single Event Upsets (SEUs) in sensitive electronic components, leading to system malfunctions and data corruption. Traditional reliability analysis based on older IC or LSI components may fail to account for radiation-induced effects. However, modern avionics systems equipped with state-of-the-art VLSI components are increasingly susceptible to Single Event Upsets (SEUs), potentially leading to underestimated failure rates in these advanced systems. This study introduces an integrated failure rate analysis that incorporates both the physics of failure rates resulting from aging and wear-out and soft error rates induced by atmospheric radiation. The proposed failure rate analysis of the reliability of avionics operating at altitudes of up to 18 km by combining the physics of failure rates with radiation-induced failure rates was derived using a semi-empirical SEU estimation method. Case studies using the Zynq 7000 board, sourced from AMD (San Jose, USA), confirmed that the integrated failure rate analysis provides more accurate reliability predictions compared to conventional analysis. This approach is expected to improve the accuracy of safety assessments during the preliminary development stages, leading to a shortened development timeline and enhanced design quality. Full article
(This article belongs to the Special Issue On-Board Systems Design for Aerospace Vehicles (2nd Edition))
15 pages, 9933 KiB  
Article
Nanosatellite Autonomous Navigation via Extreme Learning Machine Using Magnetometer Measurements
by Gilberto Goracci, Fabio Curti and Mark Anthony de Guzman
Aerospace 2025, 12(2), 117; https://doi.org/10.3390/aerospace12020117 - 3 Feb 2025
Viewed by 186
Abstract
This work presents an algorithm to perform autonomous navigation in spacecraft using onboard magnetometer data during GPS outages. An Extended Kalman Filter (EKF) exploiting magnetic field measurements is combined with a Single-Hidden-Layer Feedforward Neural Network (SLFN) trained via the Extreme Learning Machine to [...] Read more.
This work presents an algorithm to perform autonomous navigation in spacecraft using onboard magnetometer data during GPS outages. An Extended Kalman Filter (EKF) exploiting magnetic field measurements is combined with a Single-Hidden-Layer Feedforward Neural Network (SLFN) trained via the Extreme Learning Machine to improve the accuracy of the state estimate. The SLFN is trained using GPS data when available and predicts the state correction to be applied to the EKF estimates. The CHAOS-7 magnetic field model is used to generate the magnetometer measurements, while a 13th-order IGRF model is exploited by the EKF. Tests on simulated data showed that the algorithm improved the state estimate provided by the EKF by a factor of 2.4 for a total of 51 days when trained on 5 days of GPS data. Full article
(This article belongs to the Special Issue Deep Space Exploration)
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17 pages, 5856 KiB  
Article
Simulation and Stability Analysis of a Coupled Parachute–Payload System
by Keith Bergeron, Mehdi Ghoreyshi and Adam Jirasek
Aerospace 2025, 12(2), 116; https://doi.org/10.3390/aerospace12020116 - 31 Jan 2025
Viewed by 335
Abstract
High-fidelity simulations are used to study the stability of a coupled parachute–payload system in different configurations. A 8.53 m ring–slot canopy is attached to two separate International Organization for Standardization (ISO) container payloads representing a Twenty Foot Equivalent (TEU). To minimize risk and [...] Read more.
High-fidelity simulations are used to study the stability of a coupled parachute–payload system in different configurations. A 8.53 m ring–slot canopy is attached to two separate International Organization for Standardization (ISO) container payloads representing a Twenty Foot Equivalent (TEU). To minimize risk and as an alternative to a relatively expensive traditional test program, a multi-phase design and evaluation program using computational tools validated for uncoupled parachute system components was completed. The interaction of the payload wake suspended at different locations and orientations below the parachute were investigated to determine stability characteristics for both subsonic and supersonic freestream conditions. The DoD High-Performance Computing Modernization Program CREATETM-AV Kestrel suite was used to perform CFD and fluid–structure interaction (FSI) simulations using both delayed detached-eddy simulations (DDES) and implicit Large Eddy Simulations (iLES). After analyzing the subsonic test cases, the simulations were used to predict the coupled system’s response to the supersonic flow field during descent from a high-altitude deployment, with specific focus on the effect of the payload wake on the parachute bow shock. The FSI simulations included structural cable element modeling but did not include aerodynamic modeling of the suspension lines or suspension harness. The simulations accurately captured the turbulent wake of the payload, its coupling to the parachute, and the shock interactions. Findings from these simulations are presented in terms of code validation, system stability, and drag performance during descent. Full article
(This article belongs to the Section Aeronautics)
14 pages, 1613 KiB  
Article
The Effects of Speed on the Running Performance of a Small Two-Wheeled Lunar Rover
by Kimitaka Watanabe, Yamato Otani and Kazuto Tanaka
Aerospace 2025, 12(2), 115; https://doi.org/10.3390/aerospace12020115 - 31 Jan 2025
Viewed by 198
Abstract
Small wheeled lunar rovers tend to dig into surfaces via wheel rotation, causing them to slip and get stuck on regolith. Additionally, reducing power consumption remains a longstanding challenge. This study created a small two-wheeled rover and conducted tests at various wheel rotation [...] Read more.
Small wheeled lunar rovers tend to dig into surfaces via wheel rotation, causing them to slip and get stuck on regolith. Additionally, reducing power consumption remains a longstanding challenge. This study created a small two-wheeled rover and conducted tests at various wheel rotation speeds to assess the effects of rotation speed on its running performance. Through running tests and the measurement of reaction force, the influence of different wheel rotation speeds on running performance was clarified. Running at low rotation speeds prevented slipping and sinking. Additionally, the amount of sinkage was shown to converge to a certain level even at higher rotation speeds. These findings suggest that the maximum wheel rotation speed at which the rover avoids getting stuck allows the rover to achieve running with low-power consumption. Full article
(This article belongs to the Special Issue Space Mechanisms and Robots)
21 pages, 1687 KiB  
Article
New Approaches for the Use of Extended Mock-Ups for the Development of Air Traffic Controller Working Positions
by Lennard Nöhren, Lukas Tyburzy, Marco-Michael Temme, Kathleen Muth, Thomas Hofmann, Deike Heßler, Felix Tenberg, Eilert Viet and Michael Wimmer
Aerospace 2025, 12(2), 114; https://doi.org/10.3390/aerospace12020114 - 31 Jan 2025
Viewed by 278
Abstract
Today, integrating new functions into air traffic controller working positions or developing completely new displays are time-consuming and expensive processes. The users are often only included during the concept phase and after the main development phase is completed. Therefore, they do not have [...] Read more.
Today, integrating new functions into air traffic controller working positions or developing completely new displays are time-consuming and expensive processes. The users are often only included during the concept phase and after the main development phase is completed. Therefore, they do not have the chance to influence the design and development process by giving structural feedback. Any subsequent changes to the system after completing the main development phase will be expensive and slow. This paper proposes a new approach to integrate designers and users more tightly in the development process for digital air traffic control systems. By creating and reviewing realistic mock-ups in small iterative steps, the look and feel of future support functions can be validated in advance of the actual implementation and easily adapted if changes are requested. We performed a series of steps to evaluate the new workflow as a case study, including idea development, design, validation, and implementation into the target system. In a validation campaign with air traffic controllers, the developed design and functionalities received very positive feedback and the new workflow was successfully applied and evaluated as a case study. Full article
(This article belongs to the Special Issue Future Airspace and Air Traffic Management Design)
19 pages, 907 KiB  
Article
Augmentation Method for X-Ray Pulsar Navigation Using Time Difference of Arrival and Range Measurement, Based on Polarization Encoded Pulse Position Modulation
by Rong Jiao and Hua Zhang
Aerospace 2025, 12(2), 113; https://doi.org/10.3390/aerospace12020113 - 31 Jan 2025
Viewed by 288
Abstract
This paper addresses the use of the position difference between the reference satellite and the target spacecraft to improve X-ray pulsar navigation (XPNAV) for Earth orbit spacecraft. This is achieved by first installing an X-ray detector on the reference satellite whose position is [...] Read more.
This paper addresses the use of the position difference between the reference satellite and the target spacecraft to improve X-ray pulsar navigation (XPNAV) for Earth orbit spacecraft. This is achieved by first installing an X-ray detector on the reference satellite whose position is accurately known. The position measurement error of the reference satellite, known as the correction value, is sent to the spacecraft through the X-ray communication (XCOM) link. It is hoped that the accuracy of the spacecraft state measurement can be improved by offsetting common errors of measurement. X-ray ranging observation between the reference satellite and the target spacecraft, obtained from XCOM, can accomplish high precision in distance measurements, which can supply precise information for XPNAV. A novel pulse position modulation (PPM) polarization encode and modulation mode is used to achieve difference time transmission and range measurement simultaneously. Through the information fusion of the difference timing observation and the ranging observation, the positioning accuracy of the spacecraft is improved further. With the aim of estimating the spacecraft’s errors in location and speed, an adaptive divided difference filter (ADDF) is applied to eliminate nonlinearity. Several simulation cases are designed to verify the proposed method. Numerical simulations show that, compared with the traditional timing observation, the difference timing and ranging method can improve the position estimation accuracy by 27% and the velocity estimation accuracy by 22%. Full article
(This article belongs to the Section Astronautics & Space Science)
22 pages, 4847 KiB  
Article
Extracting the Spatial Correlation of Wall Pressure Fluctuations Using Physically Driven Artificial Neural Network
by Jian Sun, Xinyuan Chen, Yiqian Zhang, Jinan Lv and Xiaojian Zhao
Aerospace 2025, 12(2), 112; https://doi.org/10.3390/aerospace12020112 - 31 Jan 2025
Viewed by 346
Abstract
The spatial correlation of wall pressure fluctuations is a crucial parameter that affects the structural vibration caused by a turbulent boundary layer (TBL). Although the phase-array technique is commonly used in industry applications to obtain this correlation, it has proven to be effective [...] Read more.
The spatial correlation of wall pressure fluctuations is a crucial parameter that affects the structural vibration caused by a turbulent boundary layer (TBL). Although the phase-array technique is commonly used in industry applications to obtain this correlation, it has proven to be effective only for moderate frequencies. In this study, an artificial neural network (ANN) method was developed to calculate the convective speed, indicating the spatial correlation of wall pressure fluctuations and extending the frequency range of the conventional phase-array technique. The developed ANN system, based on a radial basis function (RBF), has been trained using discrete simulated data that follow the physical essence of wall pressure fluctuations. Moreover, a normalization method and a multi-parameter average (MPA) method have been employed to improve the training of the ANN system. The results of the investigation demonstrate that the MPA method can expand the frequency range of the ANN, enabling the maximum analysis frequency of convective velocity for aircraft wall pressure fluctuations to reach over 10 kHz. Furthermore, the results reveal that the ANN technique is not always effective and can only accurately calculate the wavenumber when the standard wavelength is less than four times the width of the sensor array along the flow direction. Full article
(This article belongs to the Section Aeronautics)
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17 pages, 1603 KiB  
Article
A Decreasing Horizon Model Predictive Control for Landing Reusable Launch Vehicles
by Guillermo Zaragoza Prous, Enric Grustan-Gutierrez and Leonard Felicetti
Aerospace 2025, 12(2), 111; https://doi.org/10.3390/aerospace12020111 - 31 Jan 2025
Viewed by 237
Abstract
A novel approach to model predictive control (MPC) with a decreasing horizon is analysed for guiding and controlling reusable launch vehicles (RLVs) during powered descent phases. Conventional MPC methods typically use receding horizons, where optimal control inputs are computed over fixed time intervals. [...] Read more.
A novel approach to model predictive control (MPC) with a decreasing horizon is analysed for guiding and controlling reusable launch vehicles (RLVs) during powered descent phases. Conventional MPC methods typically use receding horizons, where optimal control inputs are computed over fixed time intervals. However, when applied directly, these methods can cause a hovering-like behaviour, preventing the vehicle from reaching the landing platform, as the landing time is continually deferred at each iteration. The proposed solution addresses this problem by adjusting the prediction horizon dynamically, reducing its length over time. This dynamic adjustment is driven by a time-scaling factor and the time elapsed since the previous MPC iteration. Optimal control solutions are derived through convex optimization techniques. To evaluate the algorithm’s robustness against initial conditions, a Monte Carlo analysis is performed by varying initial position, velocity and mass. This method can also be used as a viable methodology for selecting tuning parameters for the MPC to ensure a successful and safe landing for a wide range of initial conditions. Full article
(This article belongs to the Special Issue Modeling, Simulation, and Control of Launch Vehicles)
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24 pages, 22757 KiB  
Article
Combustion Visualization and Liquid Jet in Crossflow Analysis of H2O2/Kerosene Bipropellant Thruster
by Suk Min Choi, Sangwoo Jung, Vincent Mario Pierre Ugolini and Sejin Kwon
Aerospace 2025, 12(2), 110; https://doi.org/10.3390/aerospace12020110 - 31 Jan 2025
Viewed by 226
Abstract
In the H2O2/Kerosene bipropellant thruster, a liquid fuel jet is transversely injected into a crossflow of hot oxygen and water vapor, catalytically decomposed from a liquid oxidizer. Due to the high temperature and oxygen-rich environment, kerosene is auto-ignited without [...] Read more.
In the H2O2/Kerosene bipropellant thruster, a liquid fuel jet is transversely injected into a crossflow of hot oxygen and water vapor, catalytically decomposed from a liquid oxidizer. Due to the high temperature and oxygen-rich environment, kerosene is auto-ignited without the need for an additional ignition source. Hence, fuel trajectory and breakup processes play a significant role in determining the performance of the rocket engine. However, little effort has been made to analyze these characteristics during actual rocket engine operation, mainly due to its harsh operating conditions of high temperature and pressure. In this study, an optically accessible combustion chamber was prepared to visualize the trajectory and breakup processes of the liquid jet during rocket engine operation. Physical and chemical processes inside the chamber were recorded using a high-speed camera utilizing a shadowgraph technique along with chemiluminescence suppression. Hot-fire tests were performed using 90 wt.% hydrogen peroxide and Jet A-1 in various jet-to-crossflow momentum flux ratios. Test cases with water injection replacing fuel were conducted with varying momentum flux ratios to identify the effect of the combustion process on the liquid jet. The study revealed that the existing correlations for the liquid jet trajectory commonly used for designing the H2O2/Kerosene bipropellant thruster in the past induced significant errors and suggested that the radiation heat transfer from the combustion flame downstream could affect the breakup processes upstream. A new correlation was suggested that accurately predicts the liquid fuel jet trajectory of the H2O2/Kerosene bipropellant thruster. Full article
(This article belongs to the Special Issue Green Propellants for In-Space Propulsion)
20 pages, 5727 KiB  
Article
Study on the Characteristics of a Composite Power System with a Tip-Jet-Driven Rotor
by Yifei Wu, Yun Wang, Jinwu Wu and Jianxiang Tang
Aerospace 2025, 12(2), 109; https://doi.org/10.3390/aerospace12020109 - 31 Jan 2025
Viewed by 244
Abstract
Tip-jet helicopters operate by utilizing the reaction force generated by a high-speed tip jet, offering advantages such as a simplified and compact fuselage design and a reduction in empty weight by eliminating anti-torque balancing equipment. In tip-jet helicopter research, the composite power system [...] Read more.
Tip-jet helicopters operate by utilizing the reaction force generated by a high-speed tip jet, offering advantages such as a simplified and compact fuselage design and a reduction in empty weight by eliminating anti-torque balancing equipment. In tip-jet helicopter research, the composite power system is regarded as a crucial and bottleneck element. This study employs numerical simulations to comprehensively analyze the internal flow characteristics of the gas generator and tip-jet-driven rotor within the composite power system. Specifically, an in-depth investigation has been conducted on the influence laws of various parameters on the system characteristics. These parameters encompass the tip-jet-driven rotor speed, which takes on values of 50 rad/s, 80 rad/s, 100 rad/s, 120 rad/s, and 150 rad/s, the tip-jet-driven rotor length, measured at 1585 mm, 1785 mm, 1985 mm, 2185 mm, 2385 mm, 2585 mm, and 2785 mm, and the tip-jet-driven rotor nozzle area, which is specified by six values corresponding to multiples of the straight section area of the rotor’s internal channel, namely 0.25 times, 0.5 times, 0.75 times, 1 times, 1.25 times, and 1.5 times. The analysis of the obtained results indicates several significant relationships. Firstly, it is observed that the available moment exhibits a linear decrease as the tip-jet-driven rotor speed increases. Secondly, the maximum available moment is attained when the tip-jet-driven rotor length (L) satisfies the relationship L = Vr/2ω. Additionally, the maximum available power is achieved when the transport velocity of the tip-jet-driven rotor nozzle is precisely half of the relative velocity of the nozzle. Moreover, under the condition that the mass flow rate of the tip-jet-driven rotor nozzle remains constant, a positive correlation between the available moment and the reduction in the tip-jet-driven rotor nozzle area is noted. Full article
(This article belongs to the Special Issue Innovation and Challenges in Hypersonic Propulsion)
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35 pages, 6742 KiB  
Article
Evaluation of Third-Order Weighted Essentially Non-Oscillatory Scheme Within Implicit Large Eddy Simulation Framework Using OpenFOAM
by Zhuoneng Li and Zeeshan A. Rana
Aerospace 2025, 12(2), 108; https://doi.org/10.3390/aerospace12020108 - 31 Jan 2025
Viewed by 291
Abstract
The current study investigates the performance of implicit Large Eddy Simulation (iLES) incorporating an unstructured third-order Weighted Essentially Non-Oscillatory (WENO) reconstruction method, alongside conventional Large Eddy Simulation (LES) using the Wall-Adapting Local Eddy Viscosity (WALE) model, for wall-bounded flows. Specifically, iLES is applied [...] Read more.
The current study investigates the performance of implicit Large Eddy Simulation (iLES) incorporating an unstructured third-order Weighted Essentially Non-Oscillatory (WENO) reconstruction method, alongside conventional Large Eddy Simulation (LES) using the Wall-Adapting Local Eddy Viscosity (WALE) model, for wall-bounded flows. Specifically, iLES is applied to the flow around a NACA0012 airfoil at a Reynolds number which involves key flow phenomena such as laminar separation, transition to turbulence, and flow reattachment. Simulations are conducted using the open-source computational fluid dynamics package OpenFOAM, with a second-order implicit Euler scheme for time integration and the Pressure-Implicit Splitting Operator (PISO) algorithm for pressure–velocity coupling. The results are compared against direct numerical simulation (DNS) for the same flow conditions. Key metrics, including the pressure coefficient and reattached turbulent velocity profiles, show excellent agreement between the iLES and DNS reference results. However, both iLES and LES predict a thinner separation bubble in the transitional flow region then DNS. Notably, the iLES approach achieved a 35% reduction in mesh resolution relative to wall-resolving LES, and a 70% reduction relative to DNS, while maintaining satisfactory accuracy. The study also captures detailed instantaneous flow evolution on the airfoil’s upper surface, with evidence suggesting that three-dimensional disturbances arise from interactions between separating boundary layers near the trailing edge. Full article
(This article belongs to the Special Issue Fluid Flow Mechanics (4th Edition))
27 pages, 4291 KiB  
Article
Digital Twin-Driven Design of an Ice Prediction Model
by Andrea Serino, Alberto Dagna, Eugenio Brusa and Cristiana Delprete
Aerospace 2025, 12(2), 107; https://doi.org/10.3390/aerospace12020107 - 31 Jan 2025
Viewed by 269
Abstract
This paper describes the development of an ice creation model to be used within the framework of a model-based systems engineering approach to predict the amount of ice growing on aircraft wings during flight. This model supports the preliminary design of the ice [...] Read more.
This paper describes the development of an ice creation model to be used within the framework of a model-based systems engineering approach to predict the amount of ice growing on aircraft wings during flight. This model supports the preliminary design of the ice protection system, as well as the implementation of a control system, in real-time. When the aircraft meets a high concentration of super-cooled water in the atmosphere and a low temperature, the risk of ice formation on its external surfaces is significant. This causes a decrease in aerodynamic performance, with potential loss of control of the aircraft. To mitigate this effect, ice prevention and protection systems are crucial. The characteristics of the icing phenomena are first defined, then their effects on aircraft behavior during operation are evaluated. This allows us to develop a highly parametric predictive model of the actual icing conditions experienced by the aircraft during a given flight mission. To precisely predict the ice accretion and to design an ice protection system, estimating heat fluxes involving the aircraft’s wing surfaces and the external environment is required. To allow for this, this study also develops a thermal model that is specifically applied to the above-mentioned analysis. This model includes many factors characterizing the atmospheric conditions responsible for ice creation upon the aerodynamic surfaces, and it enables an accurate estimation and quantification of all the parameters necessary to design an appropriate ice protection system. Full article
(This article belongs to the Special Issue On-Board Systems Design for Aerospace Vehicles (2nd Edition))
20 pages, 2163 KiB  
Article
Identifying Human Factors in Aviation Accidents with Natural Language Processing and Machine Learning Models
by Flávio L. Lázaro, Tomás Madeira, Rui Melicio, Duarte Valério and Luís F. F. M. Santos
Aerospace 2025, 12(2), 106; https://doi.org/10.3390/aerospace12020106 - 31 Jan 2025
Viewed by 365
Abstract
The use of machine learning techniques to identify contributing factors in air incidents has grown significantly, helping to identify and prevent accidents and improve air safety. In this paper, classifier models such as LS, KNN, Random Forest, Extra Trees, and XGBoost, which have [...] Read more.
The use of machine learning techniques to identify contributing factors in air incidents has grown significantly, helping to identify and prevent accidents and improve air safety. In this paper, classifier models such as LS, KNN, Random Forest, Extra Trees, and XGBoost, which have proven effective in classification tasks, are used to analyze incident reports parsed with natural language processing (NLP) techniques, to uncover hidden patterns and prevent future incidents. Metrics such as precision, recall, F1-score and accuracy are used to assess the degree of correctness of the predictive models. The adjustment of hyperparameters is obtained with Grid Search and Bayesian Optimization. KNN had the best predictive rating, followed by Random Forest and Extra Trees. The results indicate that the use of machine learning tools to classify incidents and accidents helps to identify their root cause, improving situational decision-making. Full article
(This article belongs to the Special Issue Machine Learning for Aeronautics (2nd Edition))
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26 pages, 17033 KiB  
Article
Cost-Effective Satellite Ground Stations in Real-World Development for Space Classrooms
by Pirada Techavijit and Polkit Sukchalerm
Aerospace 2025, 12(2), 105; https://doi.org/10.3390/aerospace12020105 - 30 Jan 2025
Viewed by 532
Abstract
This paper presents the development and outcomes of a cost-effective satellite ground station designed as a learning tool for satellite communication and wireless communication education. The study investigates accessible satellites and the methods for accessing them. The developed ground station has the capability [...] Read more.
This paper presents the development and outcomes of a cost-effective satellite ground station designed as a learning tool for satellite communication and wireless communication education. The study investigates accessible satellites and the methods for accessing them. The developed ground station has the capability to access satellites in the V, U, and L frequency bands, allowing it to receive a variety of satellite data. This includes full-disk meteorological images, high-resolution multispectral images, and scientific data from payloads of satellites in both low Earth orbit (LEO) and geostationary orbit (GEO). The ground station demonstrates capabilities similar to those of large organizations but at a significantly lower cost. This is achieved through a process of identifying educational requirements and optimizing the system for cost-efficiency. This paper presents the design demonstration, actual construction of the ground station, and results. Additionally, it compiles characteristics from real signal reception experiences from various satellites. Full article
(This article belongs to the Section Astronautics & Space Science)
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24 pages, 1526 KiB  
Article
Desired Impact Time Range Analysis Using a Deep Neural Network
by Jiang Wang, Chang Liu, Zichao Liu and Peng Huang
Aerospace 2025, 12(2), 104; https://doi.org/10.3390/aerospace12020104 - 30 Jan 2025
Viewed by 269
Abstract
This paper proposes a desired impact time feasible region estimation model based on a deep neural network. First, a specific multi-constraint guidance law is derived, and the terminal command deviations caused by conventional calculation methods are analyzed. Second, a binary search method is [...] Read more.
This paper proposes a desired impact time feasible region estimation model based on a deep neural network. First, a specific multi-constraint guidance law is derived, and the terminal command deviations caused by conventional calculation methods are analyzed. Second, a binary search method is employed to determine the desired impact time range, and samples are collected under various conditions. Next, parameters related to the desired impact time range are analyzed for their sensitivity to identify their influence, thereby improving computational accuracy and reducing sample size. Finally, the accuracy of the proposed method is validated through simulations. Compared with conventional approaches, the DNN-based model demonstrates higher accuracy and provides robust support for simultaneous multi-target engagement. Full article
(This article belongs to the Section Aeronautics)
18 pages, 1682 KiB  
Article
Residual Stress Distribution and Its Effect on Fatigue Crack Path of Laser Powder Bed Fusion Ti6Al4V Alloy
by Wenbo Sun, Yu’e Ma, Peiyao Li and Weihong Zhang
Aerospace 2025, 12(2), 103; https://doi.org/10.3390/aerospace12020103 - 30 Jan 2025
Viewed by 356
Abstract
Residual stress (RS) in laser powder bed fusion (LPBF) additive manufactured structures can significantly affect mechanical performance, potentially leading to premature failure. The complex distribution of residual stresses, combined with the limitations of full-field measurement techniques, presents a substantial challenge in conducting damage [...] Read more.
Residual stress (RS) in laser powder bed fusion (LPBF) additive manufactured structures can significantly affect mechanical performance, potentially leading to premature failure. The complex distribution of residual stresses, combined with the limitations of full-field measurement techniques, presents a substantial challenge in conducting damage tolerance analyses of aircraft structures. To address these challenges, this study developed a comprehensive simulation framework to analyze the 3D distribution of residual stresses and fatigue crack growth in LPBF parts. The 3D residual stress profiles of as-built samples in 15° and 75° build directions were computed and compared to experimental data. The fatigue crack propagation behavior of the 75° sample, considering 3D residual stress, was predicted, and the effects of residual stress redistribution under cyclic loading were discussed. It shows that the anisotropy of residual stress, influenced by the build direction, can lead to mixed-mode fracture and subsequent crack deflection. Tensile residual stress in the near-surface region and compressive stress in the inner region can cause an inverted elliptical crack front and accelerate fatigue crack growth. Full article
(This article belongs to the Section Aeronautics)
17 pages, 3795 KiB  
Review
Comprehensive Analysis of HY-2B/2C/2D Satellite-Borne GPS Data Quality and Reduced-Dynamic Precise Orbit Determination
by Xin Jin, Guangzhe Wang, Jinyun Guo, Hailong Peng, Yongjun Jia and Xiaotao Chang
Aerospace 2025, 12(2), 102; https://doi.org/10.3390/aerospace12020102 - 30 Jan 2025
Viewed by 300
Abstract
The deployment of the HY-2B/2C/2D satellite constellation marks a significant advancement in China’s marine dynamic environmental satellite program, forming a robust three-satellite network. All satellites are equipped with the “HY2_Receiver”, an indigenous technological achievement. Precise orbit determination using this receiver is critical for [...] Read more.
The deployment of the HY-2B/2C/2D satellite constellation marks a significant advancement in China’s marine dynamic environmental satellite program, forming a robust three-satellite network. All satellites are equipped with the “HY2_Receiver”, an indigenous technological achievement. Precise orbit determination using this receiver is critical for monitoring dynamic oceanic parameters such as sea surface wind fields and heights. This study presents a detailed analysis and comparison of the GPS data quality from the HY-2B/2C/2D satellites, emphasizing the impact of phase center variation (PCV) model corrections on orbit accuracy, with a particular focus on high-precision reduced-dynamic orbit determination. The experimental results demonstrate that the GPS data from the satellites exhibit consistent satellite visibility and minimal multipath errors, confirming the reliability and stability of the receivers. Incorporating PCV model corrections significantly enhances orbit accuracy, achieving improvements of approximately 0.3 cm. Compared to DORIS-derived orbits from the Centre National d’Études Spatiales (CNES), the GPS-derived reduced-dynamic orbits consistently reach radial accuracies of 1.5 cm and three-dimensional accuracies of 3 cm. Furthermore, validation using Satellite Laser Ranging (SLR) data confirms orbit accuracies better than 3.5 cm, with 3D root mean square (RMS) accuracies exceeding 3 cm in the radial (R), along-track (T), and cross-track (N) directions. Notably, the orbit determination accuracy remains consistent across all satellites within the HY-2B/2C/2D constellation. This comprehensive analysis highlights the consistent and reliable performance of the indigenous “HY2_Receiver” in supporting high-precision orbit determination for the HY-2B/2C/2D constellation, demonstrating its capability to meet the rigorous demands of marine dynamic environmental monitoring. Full article
(This article belongs to the Special Issue Orbit Determination Methods for Space Missions and Applications to the Exploration of the Solar System)
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23 pages, 3448 KiB  
Article
A Comparison of Modern Metaheuristics for Multi-Objective Optimization of Transonic Aeroelasticity in a Tow-Steered Composite Wing
by Kantinan Phuekpan, Rachata Khammee, Natee Panagant, Sujin Bureerat, Nantiwat Pholdee and Kittinan Wansasueb
Aerospace 2025, 12(2), 101; https://doi.org/10.3390/aerospace12020101 - 30 Jan 2025
Viewed by 359
Abstract
This study proposes a design procedure for the multi-objective aeroelastic optimization of a tow-steered composite wing structure that operates at transonic speed. The aerodynamic influence coefficient matrix is generated using the doublet lattice method, with the steady-state component further refined through high-fidelity computational [...] Read more.
This study proposes a design procedure for the multi-objective aeroelastic optimization of a tow-steered composite wing structure that operates at transonic speed. The aerodynamic influence coefficient matrix is generated using the doublet lattice method, with the steady-state component further refined through high-fidelity computational fluid dynamics (CFD) analysis to enhance accuracy in transonic conditions. Finite element analysis (FEA) is used to perform structural analysis. A multi-objective transonic aeroelastic optimization problem is formulated for the tow-steered composite wing structure, where the objective functions are designed for mass and critical speed, and the design constraints include structural and aeroelastic limits. A comparative analysis of eight state-of-the-art algorithms is conducted to evaluate their performance in solving this problem. Among them, the Multi-Objective Multi-Verse Optimization (MOMVO) algorithm stands out, demonstrating superior performance and achieving the best results in the aeroelastic optimization task. Full article
(This article belongs to the Special Issue Structural Dynamics Modelling, Aeroelastic Analysis and Experimental Verification Methods for Aircraft Systems)
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23 pages, 1015 KiB  
Article
FRAM-Based Analysis of Airport Risk Assessment Process
by Dominika Marzec and Jacek Skorupski
Aerospace 2025, 12(2), 99; https://doi.org/10.3390/aerospace12020099 - 29 Jan 2025
Viewed by 279
Abstract
The safety of flight operations and passengers is one of the main criteria for evaluating airport performance. Risk analysis and assessment are used to ensure safety in the airport’s decision-making process. This paper aims to formally analyze these processes and look for weaknesses [...] Read more.
The safety of flight operations and passengers is one of the main criteria for evaluating airport performance. Risk analysis and assessment are used to ensure safety in the airport’s decision-making process. This paper aims to formally analyze these processes and look for weaknesses that can lead to erroneous assessments and, thus, ineffective decisions. Given the specific nature of the issue, which requires the Safety II approach, it was assumed that the analysis would be carried out using a systems approach, considering all factors and relationships affecting the effectiveness of the examined processes. As relatively small-scale deviations from the planned operation of individual system functions are observed in real-world analyses, the Functional Resonance Analysis Method (FRAM) was selected as adequate for such situations. A formal study of the risk assessment process was carried out, focusing on two cases chosen during the initial identification of possible hazards. Applying the FRAM proved an effective way to analyze and search for functional resonance in the airport risk assessment process. It also enabled the identification of mitigating actions, which allows for breaking the chain of variability that leads to an unfavorable course of the process. Full article
(This article belongs to the Special Issue Advances in Air Traffic and Airspace Control and Management (2nd Edition))
24 pages, 1213 KiB  
Article
A Comparative Analysis of Multi-Criteria Decision-Making Methods and Normalization Techniques in Holistic Sustainability Assessment for Engineering Applications
by Sonia Malefaki, Dionysios Markatos, Angelos Filippatos and Spiros Pantelakis
Aerospace 2025, 12(2), 100; https://doi.org/10.3390/aerospace12020100 - 29 Jan 2025
Viewed by 306
Abstract
The sustainability evaluation of engineering processes and structures is a multifaceted challenge requiring the integration of diverse and often conflicting criteria. To address this challenge, Multi-Criteria Decision-Making (MCDM) methods have emerged as effective tools. However, the selection of the most suitable MCDM approach [...] Read more.
The sustainability evaluation of engineering processes and structures is a multifaceted challenge requiring the integration of diverse and often conflicting criteria. To address this challenge, Multi-Criteria Decision-Making (MCDM) methods have emerged as effective tools. However, the selection of the most suitable MCDM approach for problems involving multiple criteria is critical to ensuring robust, reliable, and actionable outcomes. Equally significant is the choice of a proper normalization technique, which plays a pivotal role in determining the robustness and reliability of the results. This study investigates the impact of common MCDM tools on the decision-making process concerning diverse aspects of sustainability. It also examines how different normalization methods influence the final outcomes. Sustainability in this context is understood as a trade-off among five key dimensions: performance, environmental impact, economic impact, social impact, and circularity. The outcome of the MCDM process is represented by an aggregated metric, referred to as the Sustainability Index (SI). This index offers a comprehensive and robust framework for evaluating sustainability and facilitating decision-making when conflicting criteria are present. To assess the effects of implementing different MCDM and normalization choices on the sustainability assessment, a dataset from the aviation sector is employed. Specifically, a typical aircraft component is analyzed as a case study for holistic sustainability assessment, utilizing data that represent the various dimensions of sustainability mentioned above, for this component. Additionally, the study investigates the influence of initial data variations and weight variations within the MCDM process on the results. The results indicate that, overall, the different MCDM and normalization methods lead to similar outcomes when applied to the design alternatives. However, a deeper dive into the results reveals that the weighted sum method, when paired with min-max normalization, appears to be more appropriate, based on the use case involved for the present investigation, due to its robustness regarding small variations in the initial data and its sensitivity to large ones. This research underscores the critical importance of selecting appropriate MCDM tools and normalization methods to enhance transparency, robustness, reliability, and consistency of sustainability assessments within a holistic framework. Full article
(This article belongs to the Special Issue 14th EASN International Conference on Innovation in Aviation & Space towards Sustainability Today & Tomorrow)
16 pages, 2646 KiB  
Article
Research on the Accumulative Damage of Flywheels Due to In-Space Charging Effects
by Dong Tian, Yanjun Feng, Hongbo Su, Xiao Zeng, Gang Liu, Yenan Liu and Jing He
Aerospace 2025, 12(2), 98; https://doi.org/10.3390/aerospace12020098 - 28 Jan 2025
Viewed by 324
Abstract
High-speed rotating flywheel bearings, designed for space applications, generate a high-resistance hydrodynamic lubrication film, which isolates the rotor, transforming it into a conductor. This phenomenon introduces a novel failure mode—flywheel bearing electrical damage caused by space charging effects. This paper first reviews the [...] Read more.
High-speed rotating flywheel bearings, designed for space applications, generate a high-resistance hydrodynamic lubrication film, which isolates the rotor, transforming it into a conductor. This phenomenon introduces a novel failure mode—flywheel bearing electrical damage caused by space charging effects. This paper first reviews the sources of common shaft voltages in flywheels and the mechanisms of electrical damage and improves the principle of deep charge causing shaft voltages in flywheel bearings, proposing that surface charge is another source of shaft voltages. The quantified analysis model of flywheel bearing electrical damage in relation to rotational speed and high-energy electron flux is derived, indicating that the damage caused by space charge–discharge to the bearing is of small magnitude and only becomes apparent after long-term accumulation, thus being easily overlooked. Based on the causal chain of electrical damage, a correlation analysis model consistent with physical principles is constructed, and the correlation between on-orbit anomalies of the flywheel and high-energy electron flux is confirmed through the use of big data. Preliminary experiments are conducted to validate all of the research results. Finally, suggestions are given for the reliable design, application, and testing of flywheels. Full article
(This article belongs to the Section Astronautics & Space Science)
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35 pages, 3688 KiB  
Review
State-of-the-Art DC-DC Converters for Satellite Applications: A Comprehensive Review
by Reshma Ravindran and Ahmed M. Massoud
Aerospace 2025, 12(2), 97; https://doi.org/10.3390/aerospace12020097 - 28 Jan 2025
Viewed by 617
Abstract
Future manned and deep space missions require an Electrical Power System (EPS) that can deliver high power while overcoming challenges like weight and volume constraints and the harsh space environment. A variety of DC-DC converters are employed to supply, store, and transmit power [...] Read more.
Future manned and deep space missions require an Electrical Power System (EPS) that can deliver high power while overcoming challenges like weight and volume constraints and the harsh space environment. A variety of DC-DC converters are employed to supply, store, and transmit power to various satellite subsystems. This paper identifies the design specifications of DC-DC converters for a range of satellite applications and offers a state-of-the-art review of non-isolated, isolated, and integrated topologies. Foreseeing the future of electric propulsion, various sources for electric propulsion are compared, and converters for electric propulsion are studied. The topologies are compared regarding practical parameters like reliability, modularity, redundancy, efficiency, and power density. Furthermore, an application-wise comparison of the topologies and the type of satellite they are suitable for is provided. Finally, the research gaps pertaining to various space applications, such as the design of DC-DC converters, electric propulsion, deep space exploration, electronic component selection, and space-based power satellites, are presented. Full article
(This article belongs to the Section Astronautics & Space Science)
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25 pages, 1350 KiB  
Article
Expanding Known Performance Capabilities of Geared Turbofan Engine When Powered by LNG and Methanol
by Sergios Villette, Alexios Alexiou, Nikolaos Aretakis and Konstantinos Mathioudakis
Aerospace 2025, 12(2), 96; https://doi.org/10.3390/aerospace12020096 - 28 Jan 2025
Viewed by 480
Abstract
As aviation demand rises, fossil jet fuel consumption follows, thus increasing focus on sustainable aviation fuels to reduce aircraft greenhouse gas emissions. While advanced technologies and optimized operations play a role, alternative fuels, especially non-drop-in options like Liquefied Natural Gas (LNG) and methanol, [...] Read more.
As aviation demand rises, fossil jet fuel consumption follows, thus increasing focus on sustainable aviation fuels to reduce aircraft greenhouse gas emissions. While advanced technologies and optimized operations play a role, alternative fuels, especially non-drop-in options like Liquefied Natural Gas (LNG) and methanol, offer promising potential for significant emission reductions if used in current aero-engines. LNG, a candidate near-term replacement of fossil jet fuel and methanol, even though a less conventional option in aviation, present advantages. Both fuels showcase the ability to generate the same thrust output by also achieving lower post-combustion temperatures, thereby enhancing component life and reducing emissions. Inversely, requesting equal post-combustion temperature as the baseline kerosene operation of the engine can produce greater thrust output, a much needed result for such fuels with low volumetric energy density, which causes greater take-off thrust demand mainly due to their larger tank requirements. This study uses advanced 0-D engine models coupled with detailed chemistry 1-D burner models and mission analysis tools to assess the aforementioned trends of LNG and methanol used to power a current geared turbofan engine. The aim of this work is to provide insights into the advantages, the limitations and the overall viability of the fuels in question as less polluting aviation fuels, addressing both environmental impact and operational feasibility in future aviation applications. According to findings of this article, when compared with Jet-A, LNG can reduce post-combustion temperature by an average of 1% or increase net-thrust by 3% while lowering CO2, NOx and CO emissions by 20%, 46% and 39%, respectively. Adversely, methanol is capable of lessening post-combustion temperature by 3% or enhancing thrust output by 10% while also reducing CO2, NOx and CO emissions by an average of 6%, 60% and 38%, respectively. Full article
(This article belongs to the Topic Theoretical, Numerical and Experimental Studies on Clean Energy and Combustion)
31 pages, 1665 KiB  
Article
Retrofitted Hydrogen-Electric Propulsion Aircraft: Performance Simulation of Critical Operating Conditions
by Wim Lammen, Pieter-Jan Dewitte and Elise Scheers
Aerospace 2025, 12(2), 95; https://doi.org/10.3390/aerospace12020095 - 27 Jan 2025
Viewed by 312
Abstract
Retrofitting regional turboprop aircraft with hydrogen (H2)-electric powertrains, using fuel cell systems (FCSs), has gained interest in the last decade. This type of powertrain eliminates CO2, NOx, and fine particle emissions during flight, as FCSs only emit water. In [...] Read more.
Retrofitting regional turboprop aircraft with hydrogen (H2)-electric powertrains, using fuel cell systems (FCSs), has gained interest in the last decade. This type of powertrain eliminates CO2, NOx, and fine particle emissions during flight, as FCSs only emit water. In this context, the “Hydrogen Aircraft Powertrain and Storage Systems” (HAPSS) project targets the development of a H2-electric propulsion system for retrofitting Dash 8-300 series aircraft. The purpose of the study described in this paper is to analyze the performance of the retrofitted H2-electric aircraft during critical operating conditions. Takeoff, as well as climb, cruise and go-around performances are addressed. The NLR in-house tool MASS (Mission, Aircraft and Systems Simulation) was used for the performance analyses. The results show that the retrofitted H2-electric aircraft has a slightly increased takeoff distance compared to the Dash 8-300 and it requires a maximum rated shaft power of 1.9 MW per propeller. A total rated FCS output power of 3.1 MW is sufficient to satisfy the takeoff requirements, at the cost of lower cruise altitude and reduced cruise speed as compared to the Dash 8-300. Furthermore, a higher-rated FCS is required to achieve the climb performance required for the typical climb profile of the Dash 8-300. Full article
(This article belongs to the Special Issue Revolutionizing Aerospace Mobility: Green Hydrogen As the Sustainable Fuel of the Future)
17 pages, 5333 KiB  
Article
Standardized Extraction of Air Traffic Control Hazard Features Based on Expert Knowledge
by Xianghua Tan, Zhipeng Cai, Zhibin Quan and Weili Zeng
Aerospace 2025, 12(2), 94; https://doi.org/10.3390/aerospace12020094 - 27 Jan 2025
Viewed by 345
Abstract
Air traffic control (ATC) hazard feature extraction is a key information retrieval task for air traffic hazard records. While text-based feature extraction ranks term importance based solely on statistical results, we aim to use external knowledge to extract features that meet the definition [...] Read more.
Air traffic control (ATC) hazard feature extraction is a key information retrieval task for air traffic hazard records. While text-based feature extraction ranks term importance based solely on statistical results, we aim to use external knowledge to extract features that meet the definition of hazards. This paper proposes a feature extraction method based on expert knowledge to define hazard features and construct a hazard analysis framework. We illustrate the model training process using communication navigation and surveillance (CNS) data, which includes candidate feature generation, feature vectorization, and cluster-based standardization. The correct structure of terms in hazard records, the vector distribution of candidate features, and the clustering effect of different methods are briefly explored. The algorithm refines and accumulates expert knowledge through iteration. The experiment results demonstrate that the dataset obtained after specific linguistic processing based on expert knowledge could extract more informative candidate features to construct analysis context by k-means. The proposed model outperformed four comparative algorithms in accuracy, reaching 82% and 86% in the air traffic control operation (ATCO) dataset and the CNS dataset, respectively. Additionally, the information-rich hazard features support safety management departments’ decision-making, reducing the cost of investigating hidden hazards. Full article
(This article belongs to the Special Issue Advances in Air Traffic and Airspace Control and Management (2nd Edition))
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20 pages, 4916 KiB  
Article
Quaternion-Based Robust Sliding-Mode Controller for Quadrotor Operation Under Wind Disturbance
by Jung-Ju Bae and Jae-Young Kang
Aerospace 2025, 12(2), 93; https://doi.org/10.3390/aerospace12020093 - 27 Jan 2025
Viewed by 294
Abstract
This paper presents a quaternion-based robust sliding-mode controller for quadrotors operating under significant wind disturbances. The proposed control method improves the reliability and efficiency of quadrotor control by eliminating the singularity problem inherent in the Euler angle method. The quadrotor dynamics and wind [...] Read more.
This paper presents a quaternion-based robust sliding-mode controller for quadrotors operating under significant wind disturbances. The proposed control method improves the reliability and efficiency of quadrotor control by eliminating the singularity problem inherent in the Euler angle method. The quadrotor dynamics and wind environment are modeled, and dynamic analysis is performed via numerical simulation. A realistic wind model is used, similar to a combination of deterministic and statistical models. The Lyapunov stability theory is utilized to prove the convergence and stability of the proposed control system. The simulation results demonstrate that the quaternion-based controller enables the quadrotor to follow the desired path and remain stable, even under external wind disturbances. Specifically, both position and attitude converge to the desired values within 10 s, demonstrating stable performance despite the challenging wind disturbances in both scenarios. Scenario 1 features turbulence with an average wind speed of 12 m/s and changing wind directions, while Scenario 2 models an environment with wind speeds that change abruptly and discretely over time, coupled with temporal variations in wind direction. Additionally, a comparative analysis with the conventional PD controller highlights the superior performance of the proposed RSMC controller in terms of trajectory tracking, stability, and energy efficiency. The rotor speeds remain within a reasonable and hardware-feasible range, ensuring practical applicability. Full article
(This article belongs to the Special Issue Flight Dynamics, Control & Simulation (2nd Edition))
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23 pages, 24213 KiB  
Article
Optical Image Generation Through Digital Terrain Models for Autonomous Lunar Navigation
by Michele Ceresoli, Stefano Silvestrini and Michèle Lavagna
Aerospace 2025, 12(2), 92; https://doi.org/10.3390/aerospace12020092 - 27 Jan 2025
Viewed by 419
Abstract
In recent years, Vision-Based Navigation (VBN) techniques have emerged as a fundamental component to enable autonomous spacecraft operations, particularly in challenging environments such as planetary landings, where ground control may be limited or unavailable. Developing and testing VBN algorithms requires the availability of [...] Read more.
In recent years, Vision-Based Navigation (VBN) techniques have emerged as a fundamental component to enable autonomous spacecraft operations, particularly in challenging environments such as planetary landings, where ground control may be limited or unavailable. Developing and testing VBN algorithms requires the availability of a large number of realistic images of the application scenario; however, these are rarely available. This paper presents a novel rendering software tool to generate accurate synthetic optical images of the lunar surface by leveraging high-resolution Digital Terrain Models (DTMs). Unlike traditional ray-tracing algorithms, the method iteratively propagates camera rays to determine their intersection with the terrain surface defined by a Digital Elevation Model (DEM). The color information is then retrieved from the corresponding Digital Orthophoto Model (DOM) through the knowledge of the ray impact points, bypassing the need for the costly computation of shadows, reflections, and refractions effects. The rendering performance is demonstrated through a comprehensive selection of images of the lunar surface under different illumination conditions and camera orientations. Full article
(This article belongs to the Special Issue Space Navigation and Control Technologies)
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12 pages, 1147 KiB  
Article
Normal Shock Waves in Chemically Reacting Flows with Exothermic and Endothermic Reactions Under High-Temperature Conditions
by Andriy A. Avramenko, Igor V. Shevchuk, Margarita M. Kovetskaya, Yulia Y. Kovetska, Andrii I. Tyrinov and Dmytro V. Anastasiev
Aerospace 2025, 12(2), 91; https://doi.org/10.3390/aerospace12020091 - 26 Jan 2025
Viewed by 298
Abstract
This article theoretically investigates the interaction of a normal shock wave in a flow with chemical reactions under high-temperature conditions. The main novelty of the work is that the thermal effect of chemical reactions is modeled as a function of the temperature. A [...] Read more.
This article theoretically investigates the interaction of a normal shock wave in a flow with chemical reactions under high-temperature conditions. The main novelty of the work is that the thermal effect of chemical reactions is modeled as a function of the temperature. A modified Rankine–Hugoniot model for a shock wave in a flow with chemical reactions has been developed. It is shown that for an exothermic reaction the pressure jump increases with increasing Arrhenius numbers. This is due to the additional energy introduced into the flow as heat is released during the chemical reaction. For endothermic reactions, the opposite trend is observed. The change in the speed of the adiabatic gas flow as it passes through a normal shock wave depending on the type of chemical reaction is clarified. The study provides comparisons between the results of the analytical and numerical solutions of the modified Hugoniot adiabatic equations. Full article
(This article belongs to the Special Issue Fluid Flow Mechanics (4th Edition))
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16 pages, 11058 KiB  
Communication
Research on a New Multifunctional Cell Sample Automatic Culture Device for Use in the Chinese Space Station
by Kui Shi, Hongtao Yang, Wei Zhang, Weining Chen, Aqi Yan and Jianwei Peng
Aerospace 2025, 12(2), 90; https://doi.org/10.3390/aerospace12020090 - 26 Jan 2025
Viewed by 379
Abstract
In order to meet the needs of scientific research in space medicine and biology, a new multifunctional automated cell sample culture device for a Chinese space station has been designed. The temperature and carbon dioxide concentration are adjustable, making it convenient for cell [...] Read more.
In order to meet the needs of scientific research in space medicine and biology, a new multifunctional automated cell sample culture device for a Chinese space station has been designed. The temperature and carbon dioxide concentration are adjustable, making it convenient for cell culture in microgravity environments of the space station. A centrifuge is used to simulate the microgravity environment, allowing for synchronous gravity and microgravity comparison during cell culture. An automated focusing visible light microscope has been designed, capable of real-time photography of cultured cells, which can receive ground commands to complete automatic focusing and image transmission. The thermal design of the cell sample culture device uses an air heating method, and the rationality of the thermal control measures has been verified through thermal simulation analysis. The designed cell sample preparation device can monitor and display the cell growth environment parameters and device performance parameters in real time on orbit. It can also control the internal temperature within the temperature range required for cell culture. Thus, it can meet the urgent needs of various cell cultures, experiments, and scientific research on a Chinese space station. Full article
(This article belongs to the Special Issue Space Sampling and Exploration Robotics)
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