Aerospace

27 pages, 3596 KB

Open AccessArticle

Assessing the Probability of Extreme Event Risks During Aircraft Operation in the Context of Urban Air Mobility Development

by Kayrat Koshekov, Nursultan Tompiyev, Farukh Yemutbayev, Nataliia Levchenko, Abay Koshekov and Rustam Togambayev

Aerospace 2026, 13(2), 206; https://doi.org/10.3390/aerospace13020206 - 23 Feb 2026

Viewed by 785

Abstract

Rapid urban air mobility (UAM) developments and new classes of vertical takeoff and landing (eVTOL) aircraft have changed the safety paradigm in urban airspace. eVTOL aircraft operations in dense urban environments are characterized by increased variability of external factors, highly dynamic flight scenarios, [...] Read more.

Rapid urban air mobility (UAM) developments and new classes of vertical takeoff and landing (eVTOL) aircraft have changed the safety paradigm in urban airspace. eVTOL aircraft operations in dense urban environments are characterized by increased variability of external factors, highly dynamic flight scenarios, and an increased likelihood of rare but potentially critical events. Traditional safety assessment approaches do not capture the specific features of eVTOL designs, power plants, autonomy algorithms, and urban air traffic characteristics; this results in low threat prediction accuracy and limited development of modern incident prevention systems. Herein, the risk profile of eVTOL aircraft is analyzed, accounting for the multifactorial nature of urban environments and the complexity of integrating such vehicles into existing UAM infrastructure. The need for quantitative methods for assessing the probability of critical situation risks is also substantiated. These methods provide a statistically accurate description of extreme events and enable the identification of hidden dependencies in complex technical and organizational systems. Approaches based on probabilistic models, extreme value analysis, and systemic processing of operational data are considered, providing increased risk assessment accuracy and a deeper understanding of mechanisms underlying hazardous events. Results demonstrate the importance of applying the extreme value theory (EVT)–Copula model, which enables the quantitative assessment of the probability of extreme situations and loss of stability of eVTOL vehicles in the context of developing UAM. This model can be employed to obtain realistic predictions of flight processes, reduce uncertainty, and create scientifically valid tools for developing effective measures to minimize the risks of extreme events—a key factor in ensuring the safety of eVTOL flights in urban airspace. Full article

(This article belongs to the Section Aeronautics)

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28 pages, 970 KB

Open AccessArticle

From Firm-Level Alignment to Institutional Coordination: European and National Funding in Spanish Aviation

by Juan-Francisco Reyes-Sánchez, Gustavo Alonso and Gustavo Morales-Alonso

Aerospace 2026, 13(2), 205; https://doi.org/10.3390/aerospace13020205 - 22 Feb 2026

Viewed by 668

Abstract

This study explores entities’ strategy to combine multiple governmental funding sources to complement their research and innovation activities. It focuses on the case of Spanish aeronautics entities and their participation in both European and national research and innovation programs over two successive periods. [...] Read more.

This study explores entities’ strategy to combine multiple governmental funding sources to complement their research and innovation activities. It focuses on the case of Spanish aeronautics entities and their participation in both European and national research and innovation programs over two successive periods. Using a mixed-methods approach, this study combines qualitative interviews with three representative entities and a quantitative analysis of project-level data. The interviews are first used to identify key variables and analytical categories, such as entity type, Joint Undertaking membership, technological focus, and temporal evolution, which then guide the quantitative analysis. Quantitative data on budgets, funding, participation, and technologies are analyzed across both periods and programs, including pairwise correlation analysis. The findings show that Spanish entities actively seek to align national and European funding at both financial and technological levels, although with uneven success in some cases. Joint Undertaking membership and position within the aeronautical value chain strongly influence the ability to participate in both programs and to accumulate funding. While many entities develop informal alignment strategies, these efforts often exceed their organizational capacity, particularly in the second period. The results highlight the need for formal, government-level coordination mechanisms to support effective alignment between European and national aeronautics funding programs. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

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24 pages, 32955 KB

Open AccessArticle

SynBag: Synthetic Training Data for Autonomous Grasping of Regolith Bags in the Lunar Environment

by Oluwadamilola O. Kadiri, Mackenzie Annis, Isabel R. Higgon and Kenneth A. McIsaac

Aerospace 2026, 13(2), 204; https://doi.org/10.3390/aerospace13020204 - 22 Feb 2026

Cited by 1 | Viewed by 783

Abstract

Accurate perception of deformable objects on the lunar surface is essential for autonomous construction and in situ resource utilization (ISRU) missions. However, the lack of representative lunar imagery limits the development of data-driven models for pose estimation and manipulation. We present SynBag 1.0, [...] Read more.

Accurate perception of deformable objects on the lunar surface is essential for autonomous construction and in situ resource utilization (ISRU) missions. However, the lack of representative lunar imagery limits the development of data-driven models for pose estimation and manipulation. We present SynBag 1.0, a large-scale synthetic dataset designed for training and benchmarking six-degree-of-freedom (6-DoF) pose estimation algorithms on regolith-filled construction bags. SynBag 1.0 employs rigid-body representations of bag meshes designed to approximate deformable structures with varied levels of feature richness. The dataset was generated using a novel framework titled MoonBot Studio, built in Unreal Engine 5 with physically consistent lunar lighting, low-gravity dynamics, and dynamic dust occlusion modeled through Niagara particle systems. SynBag 1.0 contains approximately 180,000 labeled samples, including RGB images, dense depth maps, instance segmentation masks, and ground-truth 6-DoF poses in a near-BOP format. To verify dataset usability and annotation consistency, we perform zero-shot 6-DoF pose estimation using a state-of-the-art model on a representative subset of the dataset. Variations span solar azimuth, camera height, elevation, dust state, surface degradation, occlusion level, and terrain type. SynBag 1.0 establishes one of the first open, physically grounded datasets for 6-DoF-object perception in lunar construction and provides a scalable basis for future datasets incorporating soft-body simulation and robotic grasping. Full article

(This article belongs to the Special Issue Lunar Construction)

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23 pages, 1294 KB

Open AccessArticle

Event-Driven Spatiotemporal Computing for Robust Flight Arrival Time Prediction: A Probabilistic Spiking Transformer Approach

by Quanquan Chen and Meilong Le

Aerospace 2026, 13(2), 203; https://doi.org/10.3390/aerospace13020203 - 22 Feb 2026

Viewed by 399

Abstract

Precise Estimated Time of Arrival (ETA) prediction in Terminal Maneuvering Areas (TMA) constitutes a prerequisite for efficient arrival sequencing and airspace capacity management. While data-driven approaches outperform kinematic models, conventional Recurrent Neural Networks (RNNs) exhibit limitations in modeling complex multi-aircraft spatial interactions and [...] Read more.

Precise Estimated Time of Arrival (ETA) prediction in Terminal Maneuvering Areas (TMA) constitutes a prerequisite for efficient arrival sequencing and airspace capacity management. While data-driven approaches outperform kinematic models, conventional Recurrent Neural Networks (RNNs) exhibit limitations in modeling complex multi-aircraft spatial interactions and lack the capability to quantify predictive uncertainty. Conversely, Spiking Neural Networks (SNNs) enable energy-efficient event-driven computation, yet their applicability to continuous trajectory regression is hindered by “input starvation,” where normalized state vectors fail to induce sufficient neural firing rates. This study proposes a Probabilistic Spiking Transformer (PST) architecture to integrate neuromorphic sparsity with global attention mechanisms. An Adaptive Spiking Temporal Encoding mechanism incorporating learnable linear projections is introduced to resolve the regression-spiking incompatibility, facilitating the autonomous mapping of continuous trajectory dynamics into sparse spike trains without heuristic scaling. Concurrently, a Distance-Biased Multi-Aircraft Cross-Attention (MACA) module models air traffic conflicts by weighting spatial interactions according to physical proximity, thereby embedding separation constraints into the feature extraction process. Evaluation on large-scale real-world ADS-B datasets demonstrates that the PST yields a Mean Absolute Error (MAE) of 49.27 s, representing a 60% error reduction relative to standard LSTM baselines. Furthermore, the model generates well-calibrated probabilistic distributions (Prediction Interval Coverage Probability > 94%), offering quantifiable uncertainty metrics for risk-based decision support while ensuring real-time inference suitable for operational deployment. Full article

(This article belongs to the Section Air Traffic and Transportation)

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32 pages, 1590 KB

Open AccessArticle

Aircraft Conceptual Design for Cloud Seeding: A Comparative Study of Recent Many-Objective Metaheuristics

by Pakin Champasak, Pathawee Kunakorn-ong, Yodsadej Kanokmedhakul, Sujin Bureerat, Nantiwat Pholdee and Natee Panagant

Aerospace 2026, 13(2), 202; https://doi.org/10.3390/aerospace13020202 - 22 Feb 2026

Viewed by 715

Abstract

Water scarcity and increasing climate variability have strengthened the demand for effective weather-modification technologies such as cloud seeding. In Thailand, conventional manned rainmaking aircraft remain constrained by operational range, safety risks, and sustainability considerations, motivating the development of electric vertical take-off and landing [...] Read more.

Water scarcity and increasing climate variability have strengthened the demand for effective weather-modification technologies such as cloud seeding. In Thailand, conventional manned rainmaking aircraft remain constrained by operational range, safety risks, and sustainability considerations, motivating the development of electric vertical take-off and landing unmanned aerial vehicles (eVTOL-UAVs). This paper proposes a mission-driven conceptual design and optimization framework for a cloud-seeding eVTOL-UAV, and extends it to reliability-based design optimization (RBDO) under uncertainty. The design task is formulated as a five-objective many-objective optimization problem with the following objectives: minimizing take-off weight, turn radius, and probability of failure, while maximizing endurance and climb rate, subject to stability/control and performance constraints. Ten state-of-the-art many-objective metaheuristics are benchmarked and solve the problem, and their performance is assessed using hypervolume (HV), inverted generational distance (IGD), runtime, and Friedman rank statistics. Results show that AGEMOEAII and PREA consistently provide the most competitive solution-set quality (HV/IGD) with comparable computational cost across algorithms. A deterministic–reliability comparison further demonstrates a clear robustness gap. Five representative Pareto designs from the best-performing optimizer are reported to illustrate practical trade-offs and support decision-making for sustainable, autonomous cloud-seeding operations. Full article

(This article belongs to the Special Issue Overall Aircraft Design for New Airframe Technologies, New Energy Systems, and New Operations—2nd Edition)

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24 pages, 3913 KB

Open AccessArticle

Multi-Scale Informer-Based Short-Arc Orbit Determination for Low-Earth-Orbit Satellites

by Ziwen Zhu, Zhongmin Pei, Hui Chen, Jiameng Wang and Zengying Yue

Aerospace 2026, 13(2), 201; https://doi.org/10.3390/aerospace13020201 - 21 Feb 2026

Viewed by 468

Abstract

This study addresses the shortcomings of conventional orbital dynamics methods in order to determine initial orbits for short-arc segments of space objects. By integrating the temporal characteristics of observational data, we innovate a multi-scale Informer temporal modeling approach, proposing a high-precision algorithm for [...] Read more.

This study addresses the shortcomings of conventional orbital dynamics methods in order to determine initial orbits for short-arc segments of space objects. By integrating the temporal characteristics of observational data, we innovate a multi-scale Informer temporal modeling approach, proposing a high-precision algorithm for short-arc-segment initial orbit determination. The study analyses why Informer models yield differing results across various time windows. First, a radar observation target model accounting for multiple perturbations and a training data generator were established to produce training data for the Informer. Subsequently, an Informer network framework was designed, encompassing data preprocessing, network architecture, and training algorithms. Realistic scenarios and evaluation metrics were then configured for digital simulation. The model’s feasibility for low-Earth-orbit satellites was validated through digital simulation for different scenarios. The results in Scenario 1 demonstrate that compared to DNN methods, this approach achieves improvements in Root Mean Square Error (RMSE) across six dimensions in ECI—x, y, z, vx, vy, and vz—of 84.04%, 80.56%, 41.38%, 60.00%, 89.03%, and 64.17% respectively; compared to the best results of the Gibbs method across different windows, this approach improves the RMSE by 25%, 23%, and 46% in the three velocity dimensions (vx, vy, and vz) in the ECI frame, respectively. The results in Scenario 2 demonstrate the universality of this method. Furthermore, the reasons for differing outcomes across Informer models with varying time windows were analyzed, alongside the rationale for the integrated Informer model outperforming individual Informer models. Full article

(This article belongs to the Section Astronautics & Space Science)

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30 pages, 391 KB

Open AccessArticle

Formulating a Learning Assurance-Based Framework for AI-Based Systems in Aviation

by Friedrich Werner, Johann Maximilian Christensen, Thomas Stefani, Frank Köster, Elena Hoemann and Sven Hallerbach

Aerospace 2026, 13(2), 200; https://doi.org/10.3390/aerospace13020200 - 19 Feb 2026

Viewed by 661

Abstract

The European Union Aviation Safety Agency (EASA) is developing guidelines to certify AI-based systems in aviation with learning assurance as a key framework. Central to the learning assurance are the definitions of a Concept of Operations, an Operational Domain, and an AI/ML constituent [...] Read more.

The European Union Aviation Safety Agency (EASA) is developing guidelines to certify AI-based systems in aviation with learning assurance as a key framework. Central to the learning assurance are the definitions of a Concept of Operations, an Operational Domain, and an AI/ML constituent Operational Design Domain (ODD). However, because no further guidance on these concepts is provided to developers, this work introduces a framework for defining them. For the concepts of the Operational Domain of the overall system and the AI/ML constituent ODD, a tabular definition language is introduced. Furthermore, processes are introduced to define the different necessary artifacts. During the specification process for the AI/ML constituent ODD, existing steps were identified and consolidated, including the identification of domain-specific concepts for the AI/ML constituent. To validate the framework, it was applied to the pyCASX system, which employs neural-network-based compression. For this use case, the framework produced an AI/ML constituent ODD with finer detail than other ODDs defined for the same airborne collision avoidance use case. Thus, the proposed novel framework is an important step toward a holistic approach aligned with EASA’s guidelines. Full article

(This article belongs to the Section Aeronautics)

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26 pages, 4418 KB

Open AccessArticle

Novel Predefined-Time Sliding Mode Fault-Tolerant Control for Hypersonic Vehicle Attitude Tracking

by Yufei Zhang, Tao Li, Weifang Chen and Hua Yang

Aerospace 2026, 13(2), 199; https://doi.org/10.3390/aerospace13020199 - 19 Feb 2026

Cited by 1 | Viewed by 457

Abstract

This article proposes a novel predefined-time sliding mode fault-tolerant control method for the attitude tracking of hypersonic vehicles subject to actuator failures and external disturbance. A novel sufficient condition of the Lyapunov function ensuring predefined-time stability and practical predefined-time stability is established, which [...] Read more.

This article proposes a novel predefined-time sliding mode fault-tolerant control method for the attitude tracking of hypersonic vehicles subject to actuator failures and external disturbance. A novel sufficient condition of the Lyapunov function ensuring predefined-time stability and practical predefined-time stability is established, which serves as the theoretical basis for the controller design. In contrast to existing Lyapunov conditions, this formulation provides greater design flexibility. Based on this theoretical foundation and an extended state observer, a predefined-time sliding mode controller is developed. The controller ensures system robustness while enabling an accurate estimate of the settling time upper bound, which is independent of initial conditions. Furthermore, the actual settling time can be tuned via the preset parameters. Finally, the proposed controller is evaluated on a hypersonic vehicle model subject to actuator bias, loss of effectiveness faults, and external disturbance. Numerical simulations demonstrate that the proposed method exhibits superior performance, including faster convergence, lower tracking errors, and enhanced robustness and fault tolerance, compared to an existing predefined-time sliding mode control approach. Full article

(This article belongs to the Section Aeronautics)

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25 pages, 7211 KB

Open AccessArticle

Assessing the Fidelity of Steady-State MRF Modeling for UAV Propeller Performance in Non-Axial Inflow

by Lorena Aular, Pedro Quintero, Roberto Navarro, Andrés Tiseira and Sébastien Prothin

Aerospace 2026, 13(2), 198; https://doi.org/10.3390/aerospace13020198 - 18 Feb 2026

Cited by 1 | Viewed by 841

Abstract

The aerodynamic behavior of small-scale UAV propellers operating under non-axial inflow conditions poses a significant prediction challenge due to the presence of strong azimuthal asymmetries, inherently unsteady flow phenomena, and Reynolds number effects that dominate forward flight conditions. Although numerical models based on [...] Read more.

The aerodynamic behavior of small-scale UAV propellers operating under non-axial inflow conditions poses a significant prediction challenge due to the presence of strong azimuthal asymmetries, inherently unsteady flow phenomena, and Reynolds number effects that dominate forward flight conditions. Although numerical models based on the Moving Reference Frame (MRF) formulation combined with steady RANS solvers are widely used in engineering practice because of their low computational cost, the precise limits of their applicability in crossflow configurations remain poorly defined. This work conducts a comprehensive numerical investigation that systematically compares steady RANS–MRF predictions against time-accurate URANS simulations across a wide range of advanced ratios and rotor tilt angles. Rigorous validation of the computational framework against experimental data in axial and near-axial regimes demonstrates excellent agreement, with deviations below 5% in propulsive efficiency. The results clearly identify the operational envelope within which MRF-based steady models remain valid under non-axial inflow. In particular, the steady approach exhibits robust performance for low-to-moderate advance ratios, where global errors in thrust and power remain below 10% for

μ = 0.40

. However, the fidelity of the method deteriorates sharply under extreme edgewise-flight conditions (

μ = 0.70)

, in which the crossflow component dominates the aerodynamic field, the “frozen-rotor” assumption progressively loses mathematical consistency, and the solver may converge toward steady solutions that no longer represent a physically meaningful flow state. The URANS analysis further reveals two critical phenomena that cannot be captured by steady-state models. First, at high advance ratios, the retreating blade encounters an extensive region of reverse flow, which induces negative sectional thrust and strongly anharmonic load waveforms. This behavior has direct implications for structural design: the peak-to-peak amplitude of thrust oscillation in edgewise flight can exceed the mean thrust level, implying extreme cyclic loading and a high risk of high-cycle fatigue. Second, the simulations quantify the emergence of off-axis parasitic moments (pitching and rolling), which are negligible in vertical flight but reach magnitudes comparable to the total aerodynamic torque in forward-flight conditions. Taken together, these findings highlight the need for a hybrid-fidelity strategy in UAV propulsion analysis: employing steady RANS–MRF within the validated domain for energetic assessments, while relying on time-accurate URANS for mandatory evaluation of structural loading, vibration, and control logic in critical high-speed regimes. Full article

(This article belongs to the Section Aeronautics)

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18 pages, 5301 KB

Open AccessArticle

DDES-Informed Development of a Helicity-Based Turbulence Model: Validation on Corner Separation and Aeronautical Flows

by Wei Sun, Haijin Yan, Bangmeng Xue, Feng Feng and Zhouteng Ye

Aerospace 2026, 13(2), 197; https://doi.org/10.3390/aerospace13020197 - 18 Feb 2026

Viewed by 485

Abstract

Accurate prediction of separated flows remains a critical challenge for Reynolds-Averaged Navier–Stokes (RANS) simulations, primarily due to the tendency of standard turbulence models to overpredict separation. To address this limitation, this study develops and validates a helicity-augmented variant of Menter’s Shear Stress Transport [...] Read more.

Accurate prediction of separated flows remains a critical challenge for Reynolds-Averaged Navier–Stokes (RANS) simulations, primarily due to the tendency of standard turbulence models to overpredict separation. To address this limitation, this study develops and validates a helicity-augmented variant of Menter’s Shear Stress Transport (SST) model within a high-fidelity, data-guided framework. First, a scale-resolving database, capturing the physics of corner separation, is established via an improved Delayed Detached Eddy Simulation (DDES) of a linear compressor cascade. Insights from this database directly inform the integration of a normalized helicity parameter into the SST formulation, enabling dynamic modulation of the turbulent eddy viscosity to account for non-equilibrium turbulence and energy backscatter in three-dimensional (3D) vortical flows. The enhanced SST model is subsequently validated against experimental data for two benchmark aerodynamic configurations: ARA M100 wing–fuselage and DLR-F6 aircraft models. Results demonstrate that the proposed correction significantly improves the prediction of separation topology and aerodynamic coefficients, delays the predicted onset of stall, and achieves closer agreement with measurements. These findings confirm the DDES-guided helicity correction as an effective strategy for enhancing the predictive fidelity of RANS models in simulating the complex separated flows encountered in practical aeronautical applications. Full article

(This article belongs to the Section Aeronautics)

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14 pages, 2808 KB

Open AccessArticle

Development and Verification of Small Mammal Life Support System for Microgravity Environment in Space

by Ru Yuan, Yixi Wang, Wenting Gao, Xiaojun Yan, Jianzhong Gu, Weibo Zheng, Fangwu Liu, Tianda Li and Tao Zhang

Aerospace 2026, 13(2), 196; https://doi.org/10.3390/aerospace13020196 - 18 Feb 2026

Viewed by 474

Abstract

With the development of the deep space exploration missions, performing in-orbit experiments with small mammals to investigate the effects of microgravity and cosmic radiation on mammalian life becomes increasingly important. In this study, a small mammal husbandry and life support system for small [...] Read more.

With the development of the deep space exploration missions, performing in-orbit experiments with small mammals to investigate the effects of microgravity and cosmic radiation on mammalian life becomes increasingly important. In this study, a small mammal husbandry and life support system for small mammal life support in the microgravity environment of space stations has been developed. The system consists of small mammal feeding device, mouse experiment unit, environmental control module and upward/downward life support devices. The system combines gas circulation, dynamic oxygen source, exhaust gas absorption, temperature and humidity control and the on-board monitoring of several parameters into a closed loop control system and a hermetic system. The circulation in the system is uniform, and there is an excellent gas exchange performance within the system in closed environment, which was verified by computational fluid dynamics numerical simulation of gas distribution and exhaust gas purification. The system can protect samples during transportation by using flexible packaging and cushioning structure. The system can satisfy the requirements of oxygen, food and water supply to ensure the feeding of mice throughout their life cycle in space. The research results lay a foundation for the development of deep-space life support system and long-term mammalian experiments in space stations. Full article

(This article belongs to the Section Astronautics & Space Science)

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32 pages, 6063 KB

Open AccessArticle

DBO-PSO: Mechanism Modeling Method for the E-ECS of B787 Aircraft Based on Adaptive Hybrid Optimization

by Yanfei Han, Zixuan Bai, Fuchao Chen, Tong Mu, Lunlong Zhong and Renbiao Wu

Aerospace 2026, 13(2), 195; https://doi.org/10.3390/aerospace13020195 - 18 Feb 2026

Viewed by 468

Abstract

In view of the highly coupled, time-varying, and susceptible to differences in aircraft configuration of the Boeing 787 Electric Environmental Control System (E-ECS), a simplified mechanism model based on effectiveness-number of transfer units is proposed. Firstly, considering the influence of differences in aircraft [...] Read more.

In view of the highly coupled, time-varying, and susceptible to differences in aircraft configuration of the Boeing 787 Electric Environmental Control System (E-ECS), a simplified mechanism model based on effectiveness-number of transfer units is proposed. Firstly, considering the influence of differences in aircraft configuration, part number, and optional components, a heat conduction correction coefficient is introduced to adjust the calculation process of heat exchange efficiency. Secondly, the steady-state characteristic equation of the electric compressor/turbine is established by utilizing the principle of isentropic work. Then, the outlet temperature value of the water removal component is calculated by using secondary heat recovery technology. Finally, to solve the problem of easily getting stuck in local optima during high-dimensional parameter identification, an adaptive hybrid optimization algorithm combining Dung Beetle Optimization (DBO) with mutation operator and Particle Swarm Optimization (PSO) is proposed. The experimental results show that the proposed mechanism model can achieve dynamic representation of the outlet temperature of each component of E-ECS under different aircraft stages. The DBO-PSO algorithm has a fast convergence speed and a low probability of falling into local optima. The temperature values calculated by the model have high computational accuracy, which can provide reliable data support for component level E-ECS health monitoring and early fault warning. Full article

(This article belongs to the Special Issue AI, Machine Learning and Automation for Air Traffic Control (ATC))

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20 pages, 11149 KB

Open AccessArticle

Reduced-Order Modeling of Sweeping Jet Actuators Using Eigenvalue-Sorted Dynamic Mode Decomposition

by Shafi Al Salman Romeo, Mobashera Alam and Kursat Kara

Aerospace 2026, 13(2), 194; https://doi.org/10.3390/aerospace13020194 - 17 Feb 2026

Cited by 1 | Viewed by 625

Abstract

Sweeping jet actuators (SJAs) are promising for active flow control in aerospace systems, but integrating actuator-resolved unsteady CFD into full-configuration simulations is often impractical due to small geometric scales and

O (10^{2})

Hz oscillations that demand fine grids and small [...] Read more.

Sweeping jet actuators (SJAs) are promising for active flow control in aerospace systems, but integrating actuator-resolved unsteady CFD into full-configuration simulations is often impractical due to small geometric scales and

O (10^{2})

Hz oscillations that demand fine grids and small time steps. This work develops a reduced-order modeling (ROM) framework to generate time-resolved boundary conditions at the actuator exit from SJA flow data. Dynamic mode decomposition (DMD) is particularly attractive for this purpose because it provides a linear, data-driven input–output representation of the actuator effect, even though it does not explicitly model the underlying nonlinear switching mechanism. We introduce an eigenvalue-sorted dynamic mode decomposition (ES-DMD) method that performs stability-aware mode ranking based on the discrete-time DMD eigenvalues, prioritizing modes with

ℜ (λ)

closest to unity to retain near-neutrally stable oscillatory dynamics, improving robustness relative to conventional amplitude-based selections for high-frequency oscillatory flows. The method is evaluated across multiple operating conditions, with detailed analysis performed for the highest mass-flow case (

\dot{m} = 0.01

lb/s), representing the most dynamically demanding condition considered. Across multiple operating conditions, ES-DMD yields consistent reconstructions of the dominant switching dynamics. For one-dimensional exit-plane profiles, combining ES-DMD with time-delay embedding enables accurate reconstruction and multi-period prediction using only 20 modes (7.6% of the full system rank). The proposed approach provides a practical pathway to incorporate unsteady SJA effects into large-scale aerospace CFD through compact, predictive boundary-condition models. Full article

(This article belongs to the Section Aeronautics)

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41 pages, 13373 KB

Open AccessArticle

Experimental Validation of a Stepwise Automatic Determination Method for TECS Parameters in ArduPilot Based on Steady-State Assessment

by Ryoya Fukada, Kazuaki Hatanaka and Mitsutomo Hirota

Aerospace 2026, 13(2), 193; https://doi.org/10.3390/aerospace13020193 - 17 Feb 2026

Viewed by 1151

Abstract

We propose a stepwise in-flight method for automatically determining flight-envelope-related parameters for the longitudinal control of small fixed-wing unmanned aerial vehicles (UAVs), including pitch-angle limits, maximum climb and sink rate limits, and the cruise (trim) throttle. The method performs steady-state evaluation using onboard [...] Read more.

We propose a stepwise in-flight method for automatically determining flight-envelope-related parameters for the longitudinal control of small fixed-wing unmanned aerial vehicles (UAVs), including pitch-angle limits, maximum climb and sink rate limits, and the cruise (trim) throttle. The method performs steady-state evaluation using onboard state estimates and sequentially updates the parameter set of ArduPilot’s energy-based longitudinal controller (Total Energy Control System, TECS). The algorithm was implemented in ArduPilot Plane v4.6.1 via Lua scripting, enabling real-time parameter determination and immediate application during flight. The proposed procedure was assessed in software-in-the-loop (SITL) simulations and further validated through flight experiments. The results demonstrated that the target parameters could be automatically identified during flight and implemented in real time. The proposed method is expected to reduce reliance on expert trial-and-error and contribute to improving portability across airframes and configuration changes. Full article

(This article belongs to the Special Issue Advances in UAVs: Design Methods, Performance Enhancement Techniques and Technologies)

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22 pages, 1392 KB

Open AccessArticle

Disaster Relief Coverage Path Planning for Fixed-Wing UAV Based on Multi-Selector Genetic Algorithm and Reinforcement Learning

by Jing Yang, Xuemeng Lu and Mingyang Cui

Aerospace 2026, 13(2), 192; https://doi.org/10.3390/aerospace13020192 - 17 Feb 2026

Cited by 1 | Viewed by 585

Abstract

When a fixed-wing Unmanned Aerial Vehicle (UAV) conducts All-Weather Post-Disaster Coverage Path Planning (PDCPP), the commonly used Sequential Path Coverage (SPC) method tends to generate redundant flight distance during turning transitions between adjacent coverage paths, which in turn increases the UAV’s flight energy [...] Read more.

When a fixed-wing Unmanned Aerial Vehicle (UAV) conducts All-Weather Post-Disaster Coverage Path Planning (PDCPP), the commonly used Sequential Path Coverage (SPC) method tends to generate redundant flight distance during turning transitions between adjacent coverage paths, which in turn increases the UAV’s flight energy consumption and thereby compromises the timeliness of rescue information acquisition. To address these challenges, this paper proposes a Multi-Selector Genetic Algorithm with Reinforcement Learning (MSGA-RL). It enhances population diversity through a distance-priority heuristic greedy initialization strategy, employs a multi-selector crossover operator to improve both solution diversity and convergence speed, and integrates a reinforcement learning-based individual retention mechanism with an elite pool protection strategy to prevent premature convergence. To simulate post-disaster scenarios, the disaster-affected area is modeled as a convex polygonal region with obstacles, while the flight energy consumption and stability of MSGA-RL are evaluated under different numbers of coverage paths. Simulation results indicate that, across all coverage path settings, MSGA-RL consistently achieves lower flight energy consumption than SPC, the Genetic Algorithm (GA), and the Dubins-based Enhanced Genetic Algorithm (DEGA), while exhibiting superior stability. In particular, in the convex quadrilateral scenario with 50 coverage paths, the flight energy consumption of MSGA-RL is reduced by 52.80%, 32.06%, and 15.96% compared with SPC, GA, and DEGA, respectively. Full article

(This article belongs to the Special Issue Advances in UAV Technology: Dynamics, Guidance, Navigation, and Control of Transformative Aerial Vehicles)

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20 pages, 3430 KB

Open AccessReview

Research Overview on Spike Stall Inception and Slotted Casing Treatment in Aeroengine Compressors

by Qianfeng Zhang, Zemin Bo and Shengfang Huang

Aerospace 2026, 13(2), 191; https://doi.org/10.3390/aerospace13020191 - 17 Feb 2026

Viewed by 449

Abstract

Rotating stall and surge are complex, unsteady flow instability phenomena in aeroengine compressors that pose serious threats to the safety and reliability of both the compressor and the engine as a whole. As aeroengine performance continues to improve, the average stage total pressure [...] Read more.

Rotating stall and surge are complex, unsteady flow instability phenomena in aeroengine compressors that pose serious threats to the safety and reliability of both the compressor and the engine as a whole. As aeroengine performance continues to improve, the average stage total pressure ratio and stage loading have steadily increased, presenting significant challenges in designing compressors with sufficient stall margins. In this study, we review key advances in the understanding of axial compressor instability, organizing prior research into three representative historical periods. This chronological framework aims to clarify evolving theoretical insights into the relationship between flow instability and tip-region flow dynamics in modern axial compressors. We then summarize the development of casing treatments, including their discovery, major configurations, and applicability across different compressor types. Subsequently, we systematically examine research on slot-type casing treatments, covering early-stage performance investigations, structural optimization based on experimental and numerical methods, and the underlying mechanisms responsible for stability enhancement. Finally, we offer recommendations and outline future research directions to guide further advancements in this field. Full article

(This article belongs to the Section Aeronautics)

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29 pages, 3715 KB

Open AccessArticle

Bi-Level Scheduling for Beijing-Tianjin-Airport Cluster Departures

by Ying Peng, Zhaokun Wan, Bin Jiang and Longhui Ran

Aerospace 2026, 13(2), 190; https://doi.org/10.3390/aerospace13020190 - 16 Feb 2026

Cited by 1 | Viewed by 834

Abstract

The rapid growth of air traffic demand and limited airspace resources have made efficient coordination in multi-airport systems a critical challenge. This paper develops a bi-level air–ground collaborative scheduling model for the Beijing-Tianjin-Airport cluster, integrating terminal-area departure sequencing (upper level) with airport surface [...] Read more.

The rapid growth of air traffic demand and limited airspace resources have made efficient coordination in multi-airport systems a critical challenge. This paper develops a bi-level air–ground collaborative scheduling model for the Beijing-Tianjin-Airport cluster, integrating terminal-area departure sequencing (upper level) with airport surface taxi and pushback scheduling (lower level), where the upper-level model minimizes departure delays, maximizes airport satisfaction, and reduces fairness deviation, while the lower-level model optimizes taxi routing and pushback timing. To solve the model, NSGA-II is applied to the upper-level sequencing problem and a Genetic-Simulated Annealing algorithm is used for surface scheduling. Empirical evaluation using operational data from Beijing Capital, Beijing Daxing, and Tianjin Binhai airports shows that the proposed approach reduces total departure delay by 49.4%, lowers average taxi time by up to 40.4%, and improves overall airport satisfaction by 5.2%, while reducing fairness deviation by 52.6%. These results demonstrate that the framework effectively enhances efficiency and equity in multi-airport departure operations. Full article

(This article belongs to the Special Issue Emerging Trends in Air Traffic Flow and Airport Operations Control)

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18 pages, 12200 KB

Open AccessArticle

An Efficient Design-to-Verification Framework for CubeSat ADCS: Application to INHA RoSAT

by Hye-Eun Yoo, Chang-Oh Kim, Sung-Hoon Mok, Jisoo Yu and Keeyoung Choi

Aerospace 2026, 13(2), 189; https://doi.org/10.3390/aerospace13020189 - 16 Feb 2026

Viewed by 726

Abstract

CubeSats are increasingly adopted for space missions due to their low cost and short development cycles. However, their attitude determination and control systems (ADCS) often suffer from limited verification environments and constrained hardware configurations. This study addresses the development and verification of a [...] Read more.

CubeSats are increasingly adopted for space missions due to their low cost and short development cycles. However, their attitude determination and control systems (ADCS) often suffer from limited verification environments and constrained hardware configurations. This study addresses the development and verification of a flight-ready ADCS for the INHA RoSAT 3U CubeSat under realistic constraints in hardware, software, and test infrastructure. A model-based design (MBD) approach is adopted to construct an integrated development pipeline covering algorithm design, simulation, automatic C code generation, and integration with flight software (FSW). The generated code is embedded into a closed commercial onboard computer framework while preserving consistency across model-in-the-loop (MIL) and processor-in-the-loop (PIL) verification stages. To compensate for the lack of full hardware-in-the-loop (HIL) facilities, a FlatSat-based Sensor-to-Actuator test strategy is introduced to validate critical hardware–software interfaces including signal polarity, unit consistency, mounting orientation, and data flow using actual flight hardware. Furthermore, a fault-aware hierarchical attitude control scheme is defined in which the controller transitions to an alternative controller upon actuator fault indications. The presented approach demonstrates a practical ADCS development and verification strategy suitable for resource-constrained CubeSat missions, providing guidance for teams facing similar limitations in cost, resources, and test infrastructure. Full article

(This article belongs to the Section Astronautics & Space Science)

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31 pages, 10739 KB

Open AccessArticle

Multi-Point Contact Dynamics of a Novel Self-Centring Mechanism for In-Space Robotic Assembly

by Yuanxin Wang, Jiafu Liu, Shujie Ma, Jianping Jiang, Yuanyuan Li and Xing Wang

Aerospace 2026, 13(2), 188; https://doi.org/10.3390/aerospace13020188 - 16 Feb 2026

Viewed by 500

Abstract

Autonomous in-space assembly using a free-flying robot can lead to residual vibrations and positioning errors of the target modules during the grasping process. This places stringent demands on end-effectors, which must tolerate large misalignments while maintaining high positioning accuracy. In this regard, this [...] Read more.

Autonomous in-space assembly using a free-flying robot can lead to residual vibrations and positioning errors of the target modules during the grasping process. This places stringent demands on end-effectors, which must tolerate large misalignments while maintaining high positioning accuracy. In this regard, this paper presents a novel self-centring mechanism, which consists of two self-centring fingers mounted on the end-effector and a double V-groove mechanism attached to the target module. The proposed compact structural design passively corrects substantial parallel offsets and angular misalignments between the end-effector and the module. A multi-point contact model consistent with this mechanism is then developed using the virtual sphere layer method to describe the self-centring process. This model incorporates a normal contact force model and a three-dimensional bristle frictional force model to characterise the multi-point bouncing contact behaviours during the self-centring process. Numerical simulations and experimental tests involving the grasping of a module with a single robotic arm confirm that the self-centring mechanism effectively eliminates initial misalignments, achieving sub-millimetre positioning accuracy. The measured parallel offsets and contact forces align closely with numerical predictions, with minor discrepancies attributed to environmental noise and vibrations from the elastic bungees in the gravity compensation system. Finally, the self-centring mechanism is applied to grasp two modules with a dual-arm robot in the Space Proximity Operations Test facility. The centroid displacements of the robot closely match the simulation results, further validating the accuracy of the proposed multi-point contact model. Full article

(This article belongs to the Special Issue Advanced Manufacturing, Assembly, and Testing Technologies for Spacecraft)

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25 pages, 14826 KB

Open AccessArticle

Parametric Evaluation of Morphed Wing Effectiveness

by Guido Servetti, Enrico Cestino and Giacomo Frulla

Aerospace 2026, 13(2), 187; https://doi.org/10.3390/aerospace13020187 - 14 Feb 2026

Viewed by 856

Abstract

Recently, continuous improvements in aircraft manoeuvrability and fuel consumption reduction have led researchers to investigate additional wing configurations based on morphing concepts. Morphing is also a potential solution for noise level reduction and may therefore represent an additional benefit. The advantages of morph-type [...] Read more.

Recently, continuous improvements in aircraft manoeuvrability and fuel consumption reduction have led researchers to investigate additional wing configurations based on morphing concepts. Morphing is also a potential solution for noise level reduction and may therefore represent an additional benefit. The advantages of morph-type schemes over traditional control surfaces during specific manoeuvres become a key parameter in the preliminary design stage. In this work, three types of airfoil morphing applied to a typical basic wing are considered and analysed: leading-edge morphing, trailing-edge morphing, and rib twist. The aerodynamic performance of each configuration is evaluated through a numerical procedure combining a panel method and a vortex lattice method. Drag reduction in morphed versus conventional wings under identical flight conditions is quantified, allowing the identification of the most efficient configuration. The analyses consider both roll manoeuvres and high-lift flight phases by evaluating changes in design parameters—such as chord-wise hinge positions, span-wise morph distribution, and morphing angles—which are compared and discussed. For the rolling manoeuvre, increasing the span-wise morphing region improves drag reduction, but not by more than 5%. When shifting the hinge position from 60% to 80% of the chord, similar drag reduction levels can be achieved, although the required morph angle differs under the same conditions. The effect of different drag components is also assessed, showing that the induced drag component is predominant for low aspect ratio wings, whereas parasite drag becomes significant at higher aspect ratios. Optimal geometrical configurations are presented and discussed for both manoeuvres. For the rolling, hinge positions yielding typical rolling moment coefficients (i.e., −0.05, −0.06, and −0.08) lie between 65% and 75% of the chord, with span-wise morphing ranges 40% < y_rib < 60% producing drag reduction up to 40% compared with a conventional wing. For the high-lift conditions, configurations between 65% < x_hinge < 80% and 50% < y_rib < 90% allow a drag reduction which can go up to 60%. Another beneficial effect is also observed for the yawing moment coefficient C_n with a reduction of more than 20% for larger aileron surfaces. Full article

(This article belongs to the Special Issue Aeroelasticity, Volume V)

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16 pages, 2189 KB

Open AccessArticle

Research on the Laser Ranging of Runaway Space Objects

by Guanyu Wen, Shuang Wang, Yukun Zeng, Tingyu Liu, Mingliang Zhang, Zhipeng Liang, Makram Ibrahim, Xingwei Han and Chengzhi Liu

Aerospace 2026, 13(2), 186; https://doi.org/10.3390/aerospace13020186 - 14 Feb 2026

Cited by 1 | Viewed by 533

Abstract

With the increase in human space activities, there is a significant amount of space debris as well as defunct satellites that seriously threaten the safety of spacecraft in their orbits. The laser ranging technique is one of the most accurate methods of ground-based [...] Read more.

With the increase in human space activities, there is a significant amount of space debris as well as defunct satellites that seriously threaten the safety of spacecraft in their orbits. The laser ranging technique is one of the most accurate methods of ground-based space target observation. Therefore, it is very meaningful to study efficient tracking and observation methods for defunct satellites and space debris. In this paper, time bias, which is in advance of the actual observation, was added by analyzing the deviation of the orbit prediction such as the time bias and range bias of the runaway space objects. A new method was used for the determination of the TB and RB in real-time tracking and in data processing. The data produced from the observation of the out-of-control targets, such as the Topex satellite and CZ-2C Long March Launch Vehicle, were presented and analyzed. Taking the laser ranging data of the Topex satellite obtained on 19 November 2019, as an example, the result of the first observation circle provided the initial time bias value for the second observation circle, proving that the laser ranging method for runaway space objects is effective. The results of this paper can effectively improve the acquisition efficiency of the defunct satellites. Full article

(This article belongs to the Section Astronautics & Space Science)

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22 pages, 5476 KB

Open AccessArticle

Design and Real-Time Validation of a Three-Phase Inverter Using an Interleaved Synchronous Super-Lift Luo Converter for Aircraft Power Systems

by Eralp Sener and Gurhan Ertasgin

Aerospace 2026, 13(2), 185; https://doi.org/10.3390/aerospace13020185 - 14 Feb 2026

Viewed by 489

Abstract

This paper examines a 24 kVA three-phase inverter supplied by a set of four synchronous Super-Lift Luo DC–DC converters (ISSLLC) connected in parallel to a common DC link. The converters boost a 28 V DC input to approximately 400 V, which then feeds [...] Read more.

This paper examines a 24 kVA three-phase inverter supplied by a set of four synchronous Super-Lift Luo DC–DC converters (ISSLLC) connected in parallel to a common DC link. The converters boost a 28 V DC input to approximately 400 V, which then feeds a 115 V, 400 Hz inverter intended for aircraft electrical systems. The overall system was modeled analytically, simulated using PLECS, and validated in real time on a Typhoon HIL platform. In both simulation and HIL, the DC link remained low ripple, and the inverter delivered well-balanced three-phase output voltages. The measured total harmonic distortion was 0.77%, and the power factor was close to unity, staying within MIL-STD-704F limits. The agreement between the simulation and HIL results confirms the precision and real-time feasibility of the proposed ISSLLC-based inverter for aerospace and other high-gain, high-efficiency applications. Full article

(This article belongs to the Special Issue New Trends in Aviation Development 2024–2025)

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24 pages, 5354 KB

Open AccessArticle

Integrated Aerodynamic–Propulsion Optimization for Gas-Powered Fan VTOL Systems via CFD and Genetic Algorithms

by Mohammad Javad Pour Razzaghi, Guoping Huang and Yuanzhao Zhu

Aerospace 2026, 13(2), 184; https://doi.org/10.3390/aerospace13020184 - 13 Feb 2026

Cited by 1 | Viewed by 571

Abstract

Vertical takeoff and landing (VTOL) aircraft must balance the conflicting demands of hover and cruise performance. To address the lack of integrated design methodologies in the existing literature, a unified design-optimization framework is presented, coupling high-fidelity CFD simulations with a genetic algorithm to [...] Read more.

Vertical takeoff and landing (VTOL) aircraft must balance the conflicting demands of hover and cruise performance. To address the lack of integrated design methodologies in the existing literature, a unified design-optimization framework is presented, coupling high-fidelity CFD simulations with a genetic algorithm to refine a gas-driven thrust fan (GDTF) VTOL nacelle. Key geometric parameters—fan pressure ratio pressure ratio, fan tilt, nozzle angle, tail inclination, and tip shape—were varied in a comprehensive parametric study to maximize lift-to-drag ratio and maintain constant mass flow. The optimization reveals that a nearly horizontal fan axis maximizes cruise efficiency (

\frac{L}{D} \approx 2.98

), a nozzle angle of about

22 °

offers the best lift-vs-drag compromise during transition, and refining the tip geometry yields a

10

–

20 %

performance boost. To validate the numerical predictions, a 1:1.05 scale VTOL nacelle model (fan diameter

D = 0.42 m

) was fabricated and tested in a low-speed wind tunnel at

52 \frac{m}{s}

(

R e \approx 5 \times 10^{6}

, turbulence intensity ≈ 2%). Total-pressure probes at the intake exit plane and static taps along the inner cowl wall provided detailed pressure distributions, from which exit Mach number, velocity and the equivalent flow coefficient φ (≈0.68 under test conditions) were derived. Oil-flow visualization on the external cowl surface confirmed smooth, attached streamlines with no large separation bubbles. This dual validation combining surface-flow visualization and pressure-recovery mapping demonstrates the accuracy and reliability of the proposed simulation methodology. By successfully bridging detailed CFD with genetic-algorithm-driven design and validating against comprehensive wind-tunnel measurements, this integrated approach paves the way for next-generation VTOL configurations with longer range and lower fuel consumption. Full article

(This article belongs to the Special Issue Advanced Aircraft Structural Design and Applications)

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37 pages, 1412 KB

Open AccessReview

The Evolving Paradigm of Reliability Engineering for Complex Systems: A Review from an Uncertainty Control Perspective

by Zhaoyang Zeng, Cong Lin, Wensheng Peng and Ming Xu

Aerospace 2026, 13(2), 183; https://doi.org/10.3390/aerospace13020183 - 13 Feb 2026

Cited by 1 | Viewed by 993

Abstract

Traditional reliability engineering paradigms, originally designed to prevent physical component failures, are facing a fundamental crisis when applied to today’s software-intensive and autonomous systems. In domains like aerospace, critical risks no longer stem solely from the aleatory uncertainty of hardware breakdowns, but increasingly [...] Read more.

Traditional reliability engineering paradigms, originally designed to prevent physical component failures, are facing a fundamental crisis when applied to today’s software-intensive and autonomous systems. In domains like aerospace, critical risks no longer stem solely from the aleatory uncertainty of hardware breakdowns, but increasingly from the deep epistemic uncertainty inherent in complex systematic interactions and non-deterministic algorithms. This paper reviews the historical evolution of reliability engineering, tracing the progression through the Statistical, Physics-of-Failure, and Prognostics Eras. It argues that while these failure-centric frameworks perfected the management of predictable risks, they are structurally inadequate for the “unknown unknowns” of modern complexity. To address this methodological vacuum, this study advocates for an imperative shift towards a fourth paradigm: the Resilience Era. Grounded in the principles of Safety-II, this approach redefines the engineering objective from simply minimizing failure rates to ensuring mission success and functional endurance under uncertainty. The paper introduces uncertainty control (UC) as the strategic successor to uncertainty quantification (UQ), proposing that safety must be architected through behavioral constraints rather than prediction alone. Finally, the paper proposes a new professional identity for the practitioner: the system resilience architect, tasked with designing adaptive architectures that ensure safety in an era of incomplete knowledge. Full article

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16 pages, 3343 KB

Open AccessArticle

Experimental Evaluation of Energy Consumption and Acoustic Emissions in Sub-250 g Quadcopters with Added Tubular Propeller Enclosures

by Mateusz Woźniak, Paweł Bury and Artur Kierzkowski

Aerospace 2026, 13(2), 182; https://doi.org/10.3390/aerospace13020182 - 13 Feb 2026

Viewed by 524

Abstract

This paper investigates the impact of tubed propeller design on the energy efficiency and acoustic emissions of sub-250 g quadcopters. This study was motivated by the growing popularity of ultralight UAVs and the lack of experimental data addressing the trade-offs between noise, efficiency, [...] Read more.

This paper investigates the impact of tubed propeller design on the energy efficiency and acoustic emissions of sub-250 g quadcopters. This study was motivated by the growing popularity of ultralight UAVs and the lack of experimental data addressing the trade-offs between noise, efficiency, and mass. Ten drone configurations with varying tube geometries and tip clearances were constructed using 3D-printed PLA+ frames and identical propulsion components. Experimental tests were conducted in a reverberation room to measure sound pressure levels and onboard energy consumption during hover. The results show that tubed configurations are 3–6.5 dB louder than untubed ones, with a noticeable shift toward higher frequencies. While tubes increased total power demand by 18–37% compared to the lightest design, they also reduced it by 3–17% relative to untubed drones of the same mass. The findings demonstrate that tubing improves aerodynamic efficiency only under same mass constraints and is most beneficial when mechanical protection is prioritized over noise and endurance. Full article

(This article belongs to the Special Issue Advances in UAVs: Design Methods, Performance Enhancement Techniques and Technologies)

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44 pages, 1966 KB

Open AccessArticle

Experimental Aircraft: Comparative Analysis of Governance, Funding, and Business Models

by Dionysios Markatos, Harry Psihoyos, Thomas Kalampoukas, Pierluigi Iannelli, Lorenzo Pellone, Marco Armbrust, Andreas Strohmayer, Spiros Pantelakis and Angelos Filippatos

Aerospace 2026, 13(2), 181; https://doi.org/10.3390/aerospace13020181 - 13 Feb 2026

Viewed by 1075

Abstract

Decarbonizing aviation, particularly for long-range operations, is critical for meeting international climate targets, yet it remains technically and operationally challenging. Experimental aircraft (EA) serve to enable flying research infrastructures that provide realistic flight environments for validating emerging technologies and bridging the gap between [...] Read more.

Decarbonizing aviation, particularly for long-range operations, is critical for meeting international climate targets, yet it remains technically and operationally challenging. Experimental aircraft (EA) serve to enable flying research infrastructures that provide realistic flight environments for validating emerging technologies and bridging the gap between research and future operational aircraft. While motivated by long-range aviation decarbonization, the study analyses experimental aircraft across multiple scales and missions, focusing on governance structures, funding mechanisms, and business models rather than technical performance metrics. Beyond their technical role, the success and sustainability of EA programs depend strongly on how they are governed, financed, and operated—dimensions that remain comparatively underexplored in the literature, which has primarily emphasized technical performance and flight-test results. To address this gap, this study adopts a structured, multi-method qualitative research approach combining desk-based investigation, a systematic literature review, and comparative case study analysis. The paper reviews and classifies 74 experimental aircraft programs worldwide, with a primary analytical focus on Europe and the United States, examining governance models, funding structures, and business models alongside contextual factors such as platform scale, sectoral orientation, and stakeholder involvement. The results show that most experimental aircraft function as technology demonstration and strategic innovation platforms, supported predominantly by public and public–private funding due to the high-risk and long-term nature of flight research infrastructures. Governance arrangements vary with mission and scale, balancing public oversight, industrial leadership, and academic participation. These findings support the EXAELIA project and provide a reference framework for future experimental aircraft programs. Full article

(This article belongs to the Special Issue 15th EASN International Conference on Innovation in Aviation & Space Towards Sustainability Today and Tomorrow)

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28 pages, 1486 KB

Open AccessArticle

High-Altitude Pseudo-Satellite: Prototype Conceptualization and Development

by Zvonimir Rezo, Tomo Bagarić and Sanja Steiner

Aerospace 2026, 13(2), 180; https://doi.org/10.3390/aerospace13020180 - 13 Feb 2026

Viewed by 1189

Abstract

The increasing demand for continuous and reliable air traffic surveillance over remote and oceanic regions has prompted the exploration of innovative solutions beyond traditional radar and satellite-based systems. In this context, High-Altitude Pseudo-Satellites (HAPSs) have emerged as a promising technology capable of extending [...] Read more.

The increasing demand for continuous and reliable air traffic surveillance over remote and oceanic regions has prompted the exploration of innovative solutions beyond traditional radar and satellite-based systems. In this context, High-Altitude Pseudo-Satellites (HAPSs) have emerged as a promising technology capable of extending surveillance and communication coverage within the stratosphere at significantly lower cost and greater operational flexibility. This paper presents the results of Research and Development (R&D) efforts focused on the conceptualization and development of a HAPS prototype serving as a proof of concept to enhance Air Traffic Management (ATM) surveillance capabilities. The study quantitatively examines the HAPS operational environment by classifying and evaluating the geometric, physical, environmental, thermal and atmospheric factors influencing prototype performance. The developed prototype establishes a scalable foundation for future multi-platform HAPS networks, and forthcoming research will focus on experimental validation under real-world conditions and performance optimization to enable integration into next-generation ATM systems. Full article

(This article belongs to the Section Air Traffic and Transportation)

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23 pages, 2573 KB

Open AccessArticle

Development of an Unattended Ionosphere–Geomagnetism Monitoring System with Dual-Adversarial AI for Remote Mid–High-Latitude Regions

by Cheng Cui, Zhengxiang Xu, Zefeng Liu, Zejun Hu, Fuqiang Li, Yinke Dou and Yuchen Wang

Aerospace 2026, 13(2), 179; https://doi.org/10.3390/aerospace13020179 - 13 Feb 2026

Viewed by 422

Abstract

To address coverage gaps in high-latitude space weather monitoring caused by constraints in energy, bandwidth, and labeled samples, this study presents a systematic solution deployed in Hailar, China. We constructed a Cloud–Edge–Terminal system featuring wind–solar hybrid energy and RK3588-based edge computing, achieving six [...] Read more.

To address coverage gaps in high-latitude space weather monitoring caused by constraints in energy, bandwidth, and labeled samples, this study presents a systematic solution deployed in Hailar, China. We constructed a Cloud–Edge–Terminal system featuring wind–solar hybrid energy and RK3588-based edge computing, achieving six months of stable ionospheric–geomagnetic observation under −40 °C. Furthermore, we propose a Dual-Adversarial Recurrent Autoencoder (DA-RAE) for anomaly detection. Utilizing a single-source domain strategy, the model learns physical manifolds from quiet-day data, enabling zero-shot anomaly perception in the unsupervised target domain. Field tests in March 2025 demonstrated superior generalized anomaly detection capabilities, successfully identifying both transient space weather events and environmental equipment faults (baseline drifts). This work validates the value of edge intelligence for autonomous operations in extreme environments, providing a reproducible paradigm for global ground-based networks. Full article

(This article belongs to the Special Issue Situational Awareness Using Space-Based Sensor Networks)

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23 pages, 6187 KB

Open AccessArticle

Degradation Mechanisms and Service Life Prediction of High-Performance Rubber Seals for Near-Space Unmanned Platforms

by Chunlian Duan, Hui Feng, Tianjin Cheng, Yanchu Yang, Yuanyu Liu, Jinghui Gao, Chen Li, Qing Hao, Xiang Ma, Yongxiang Li and Xiaohui He

Aerospace 2026, 13(2), 178; https://doi.org/10.3390/aerospace13020178 - 13 Feb 2026

Viewed by 618

Abstract

Low-Speed near-space aerostats (e.g., stratospheric airships and high-altitude balloons) are low-speed unmanned aerial vehicles (UAVs) extensively utilized in communication coverage, remote sensing applications, environmental monitoring, aviation support, and other fields. A paramount challenge constraining their precise and stable operation is the leakage of [...] Read more.

Low-Speed near-space aerostats (e.g., stratospheric airships and high-altitude balloons) are low-speed unmanned aerial vehicles (UAVs) extensively utilized in communication coverage, remote sensing applications, environmental monitoring, aviation support, and other fields. A paramount challenge constraining their precise and stable operation is the leakage of buoyant gas, such as helium (He), in the harsh and unpredictable near-space environment. One of the primary causes of gas leakage is the degradation of their dedicated sealing rings. This study aims to clarify the aging mechanisms of high-performance rubber seals in near-space environments and establish a reliable service life prediction model to address the gas leakage risk of unmanned platforms. Two widely used high-performance rubber materials—ethylene propylene diene monomer (EPDM) and chloroprene rubber (CR)—were subjected to accelerated aging experiments under simulated near-space environment conditions. Their degradation was then quantified through performance degradation characterization, covering mass loss, hardness, elastic deformation, and tensile strength. A predictive model was established to estimate the mass loss rates and service life of the seals. The model revealed that EPDM exhibits superior performance to CR under near-space conditions: the aging behavior is strongly dependent on material composition, thickness, and preload, while being independent of outer diameter. Results show EPDM seals have a near-space service life of 300 days (50% longer than CR’s 200 days), with aging dependent on material composition, thickness (2 mm seals degrade 110% slower than 0.5 mm ones), and preload, but independent of outer diameter. These results provide actionable design guidelines for optimizing seal materials and geometries in aerostat pressure systems, thereby advancing the development of innovative low-speed UAV technologies and the successful application of these technologies in the emerging near-space field. These findings and the proposed methodology are directly applicable to sealing system optimization for various near-space unmanned platforms (e.g., stratospheric UAVs, high-altitude autonomous balloons), enhancing their long-duration operational reliability and mission success rate in extreme environments. Full article

(This article belongs to the Section Astronautics & Space Science)

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16 pages, 17275 KB

Open AccessArticle

Surface Coating Strategies for SMA-Based Antennas in Ultra-Small Satellite Platforms

by Jurgen Vanhamel, Robin Jorissen, Dieter Reenaers and Wim Deferme

Aerospace 2026, 13(2), 177; https://doi.org/10.3390/aerospace13020177 - 13 Feb 2026

Viewed by 588

Abstract

Spaceflight has become more accessible than ever due to increased launch reliability and significant advances in electronics. Among these advancements are small-sized PocketQubes, which are small satellites (5 × 5 × 5 cm for 1P) that can be built using commercial off-the-shelf components. [...] Read more.

Spaceflight has become more accessible than ever due to increased launch reliability and significant advances in electronics. Among these advancements are small-sized PocketQubes, which are small satellites (5 × 5 × 5 cm for 1P) that can be built using commercial off-the-shelf components. A critical subsystem in these satellites is the communication system, which requires compact and deployable antennas. This work focuses on the design of deployable antennas for TU Delft’s upcoming Delfi-Twin PocketQube mission, operating in the 10 m and 6 m amateur bands. The Shape Memory Alloy (SMA) nitinol was selected as the antenna material due to its favorable mechanical and deployment characteristics. However, its high electrical resistivity limits antenna efficiency. This study investigates multiple conductive coating techniques for nitinol antenna wires, aiming to improve electrical performance while maintaining mechanical flexibility. The coatings are evaluated through electrical resistance measurements and mechanical bending tests. Among them, a DuPont ME164 ink showed the most promising performance, significantly reducing wire resistance compared to bare nitinol while preserving mechanical integrity. These results address a novel conductive coating for efficient SMA-based antennas and demonstrate a valid approach for improving deployable antennas in small-satellite applications. Full article

(This article belongs to the Section Astronautics & Space Science)

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