Aerospace

15 pages, 9933 KiB

Open AccessArticle

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

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

Open AccessArticle

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

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 CREATE

^{TM}

-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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessArticle

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

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

Open AccessReview

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

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

Open AccessArticle

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

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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24 pages, 1213 KiB

Open AccessArticle

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

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)

23 pages, 1015 KiB

Open AccessArticle

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

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))

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Aerospace

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