 Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
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- Aerospace, Vol. 12, Pages 163: Numerical Analysis of Aerodynamic and
Thermal Performance of Streamline Heat Pipe Heat Exchanger Assisted by
Fins
Authors: Weicheng Qi, Yuanwei Lyu, Honggang Zeng, Jingyang Zhang, Fenming Wang
First page: 163
Abstract: This study numerically explores the feasibility of a streamlined heat pipe heat exchanger in precooling technology in supersonic vehicles. Emphasis has been placed on the role of fins installed in the condensation section in affecting the aerodynamic and thermal characteristics of the streamline heat pipe heat exchanger. The results show that the installation of fins in the condensation section effectively improved the overall heat transfer capacity of the streamline heat pipe heat exchanger. The temperature drop with fins is up to 685 K, which is 20 K larger than the case without fins. Simultaneously, fins resulted in 6.4% and 25.4% increases in the pressure loss coefficient in the evaporation and condensation section compared to the case without fins. The aerodynamic and thermal characteristics are closely related to the mass flow rate of intake air and kerosene (RP-3). The pressure drop and temperature drop are positively related to the mass flow rate of RP-3. In contrast, as the qa increases, the heat exchange per qa decreases, and the temperature of the air outlet of the evaporation section increases correspondingly. In the evaporation section, as the qRP-3 increases, the temperature drop in the condensation section first increases and then remains unchanged, and its pressure loss coefficient decreases. The temperature drop in the intake air is positive and related to the qRP-3. The results obtained in this study are significant because they can provide technical support in the high performance of heat exchangers.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030163
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 164: Exploration of Solar Power System
Integration for Sustainable Air Transportation—A Case Study for
Seaplane Air Taxi Operations
Authors: Susan Liscouët-Hanke, Mohammad Mir, Musavir Bashir
First page: 164
Abstract: To reduce the environmental impact of airborne transportation, the aeronautic community investigates smaller aircraft with short-range operations (such as training aircraft, air taxis, or commuter aircraft) as technology incubators. This paper contributes to this effort by presenting an analysis framework and a detailed case study for integrating an auxiliary solar power system for air taxi operations. The solar power system conceptual design and analysis framework is improved to capture important effects for more realistic analysis for smaller aircraft, such as allowing the solar power system’s efficiency to be estimated as a function of aircraft mission parameters (temperature, speed, cloudiness) and providing a detailed view of the new system’s weight estimation considering potential physical integration scenarios. A detailed analysis of Harbour Air’s seaplane air taxi operations and the DHC-2 Beaver is performed using this enhanced design framework. The results show that the solar power system output exceeds the required secondary electrical power for 86% of the mission in one season; hence, it provides the potential to supplement a hybrid electric propulsion system. Secondly, the authors designed experiments to investigate the sensitivity of technology uncertainties for one critical mission. The results show that a small fuel burn reduction can be achieved with current technologies, with a promising trend of more savings with increasing system efficiency. Also, the results show that accumulated over a season’s operation, the CO2 emissions from the aircraft can be reduced. The findings indicate that integrating solar power systems can supplement traditional power sources and improve ground operations: specifically, solar energy could power a zero-emission and autonomous air-conditioning system while parked. Overall, integrating solar power into seaplane air taxi operations, even as a retrofit, presents a viable strategy for achieving more sustainable air transportation.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030164
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 165: Quantifying the Effects of Climate Change
on Aircraft Take-Off Performance at European Airports
Authors: Jonny Williams, Paul D. Williams, Federica Guerrini, Marco Venturini
First page: 165
Abstract: This work uses state-of-the-art climate model data at 30 European airport locations to examine how climate change may affect summer take-off distance required—TODR—and maximum take-off mass—MTOM—for a 30-year period centred on 2050 compared to a historical baseline (1985–2014). The data presented here are for the Airbus A320; however, the methodology is generic and few changes are required in order to apply this methodology to a wide range of different fixed-wing aircraft. The climate models used are taken from the 6th Coupled Model Intercomparison Project (CMPI6) and span a range of climate sensitivity values; that is, the amount of warming they exhibit for a given increase in atmospheric greenhouse gas concentrations. Using a Newtonian force-balance model, we show that 30-year average values of TODR may increase by around 50–100 m, albeit with significant day-to-day variability. The changing probability distributions are quantified using kernel density estimation and an illustration is provided showing how changes to future daily maximum temperature extremes may affect the distributions of TODR going forward. Furthermore, it is projected that the 99th percentile of the historical distributions of TODR may by exceeded up to half the time in the summer months for some airports. Some of the sites studied have runways that are shorter than the distance required for a fully laden take-off, which means they must reduce their payloads as temperatures and air pressures change. We find that, relative to historical mean values, take-off payloads may need to be reduced by the equivalent of approximately 10 passengers per flight, as these significant increases (as high as approximately 60%) show a probability of exceeding historical extreme values.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030165
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 166: Mission Re-Planning of Reusable Launch
Vehicles Under Throttling Fault in the Recovery Flight Based on
Controllable Set Analysis and a Deep Neural Network
Authors: Keshu Li, Wanqing Zhang, Han Yuan, Jing Zhou, Ying Ma
First page: 166
Abstract: The frequent launches of reusable launch vehicles are currently the primary approach to support large-scale space transportation, necessitating high reliability in recovery flights. This paper proposes a mission re-planning scheme to address throttling faults, which significantly affect the feasibility of powered landing. To quantify the influence of throttling capability, the concept of “controllable set (CS)” is introduced. The CS is defined as the collection of all feasible initial states that can achieve a successful powered landing and is computed using polyhedron approximation and convex optimization. Based on the CS, the physical feasibility of a power landing problem under deviations from the nominal conditions can be evaluated probabilistically. Besides, a deep neural network (DNN) is constructed to enhance the computational efficiency of the CS analysis, thereby meeting the requirements for online applications. Finally, an effective re-planning scheme is proposed to deal with throttling faults in recovery flight. This is achieved by adjusting the designed angle of attack during the endo-atmosphere unpowered descent phase and selecting the associated optimal handover conditions to initiate the powered landing. The optimal re-planning parameters are determined through a comprehensive investigation of the design space, leveraging probability-based CS analysis and computationally efficient DNN predictions. Simulations verify the accuracy of the CS computation algorithm and the effectiveness of the re-planning scheme under different fault conditions. The results indicate high feasibility probabilities of 99.97%, 98.12%, and 78.52% for maximum throttling capabilities at 65%, 75%, and 85% of nominal thrust magnitude, respectively.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030166
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 167: Passive Rotor Noise Reduction Through Axial
and Angular Blade Spacing Modulation
Authors: Chingiz Arystanbekov, Altay Zhakatayev, Basman Elhadidi
First page: 167
Abstract: This study investigates the aerodynamic and aeroacoustic performance of a novel two-stage two-bladed coaxial propeller that is axially and angularly spaced. Aerodynamic propulsive thrust and efficiency are validated and evaluated using a Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) model for the two-bladed APC27x13 propeller. Aeroacoustic assessment is conducted using a Ffowcs Williams–Hawkings integral model. A four-bladed coplanar APC27x13 propeller is simulated and considered as the baseline propeller. The CFD results suggest that changes in the rotor thrust for the coaxial blades are within 3% for propellers with 0.25D axial spacing (where D is the propeller diameter) and 30∘ angular spacing for the advance ratio of J=0.3–0.5. The aeroacoustic assessment for J=0.3 reveals that blades with 30∘ and 60∘ azimuthal spacing and 0.25D axial spacing significantly reduce noise compared to the baseline propeller. The reduction is attributed to the redistribution of tonal noise blade passing frequencies, resulting in a reduction in the A-weighted noise levels by up to 2 dBA. Additionally, the study accounts for the effect of the blade tip Mach number, concluding that a tip Mach number ranging between 0.7 and 0.9 is optimal for noise reduction in the 30∘ configuration. The results highlight the potential noise reduction benefits of uneven axial and angular blade spacing while maintaining similar aerodynamic performance.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030167
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 168: Space Debris Sky Survey Observation
Strategy Based on HEALPix and Greedy Algorithm
Authors: Shuqi Liu, Shaoming Hu, Junju Du, Hai Cao, Bo Zhang, Yuchen Jiang, Shuai Feng
First page: 168
Abstract: To improve the observation efficiency of space debris surveys, a basic sky survey observation strategy was developed, with the aim of observing more space debris based on the Wide Field Optical Telescope Array run by Shandong University. The characteristics of the telescope and dynamic changes in the movement and position of space debris are considered in this strategy. An objective function was designed based on these factors. Using the pixelated sphere method to finely divide the celestial area, applying the summation filtering method, and using a greedy algorithm, the benefit of the objective function can be maximized, thus generating the optimal sky survey observation strategy. Through simulation and observation experiments, we demonstrate that the greedy algorithm observation strategy significantly improves the number of space debris instances and the number of arc segments with respect to the conventional observation strategy. This not only improves the automation level of space debris observation tasks, but also significantly enhances the execution efficiency of telescopes for debris observation. It is very helpful for cataloging space debris and generating collision warnings.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030168
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 169: A Distributed Cooperative Guidance Law with
Prescribed-Time Consensus Performance
Authors: Chao Ou, Ao Shen, Zhongtao Cheng, Yaosong Long
First page: 169
Abstract: This paper proposes a prescribed-time convergent distributed cooperative guidance law that enables aircraft to reach the same location in a cooperative manner in both undirected and directed communication topologies. First, the heading error angle is designed to derive the analytical expression of the flight time. Then, the guidance law is incorporated as a bias term into the heading error angle to ensure that the remaining flight time error converges to zero within the prescribed time so as to realize the cooperative arrival of the aircraft at the same location. Finally, numerical simulations were conducted to verify the effectiveness of the proposed algorithm under both communication topologies.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030169
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 170: Asymmetric Deep Reinforcement
Learning-Based Spacecraft Approaching Maneuver Under Unknown Disturbance
Authors: Shibo Shao, Dong Zhou, Guanghui Sun, Weizhao Ma, Runran Deng
First page: 170
Abstract: Spacecraft approaching maneuver control normally uses traditional control methods such as Proportional–Integral–Derivative (PID) or Model Predictive Control (MPC), which require meticulous system design and lack robustness against unknown disturbances. To address these limitations, we propose an end-to-end asymmetric Deep Reinforcement Learning-based (DRL) spacecraft approaching maneuver (ADSAM) algorithm, which significantly enhances the robutsness of the space-approaching maneuver under large-scale unknown disturbance and Partial Observation Markov Decision Processes (POMDPs). We present a numerical simulation environment with the linear Clohessy–Wiltshire (CW) model, incorporating the Runge–Kutta 4th order method (RK4) to ensure a more accurate and efficient state transition. Experimental results also demonstrate that the effectiveness of the proposed algorithm outperforms the-state-of-the-art methods.
Citation: Aerospace
PubDate: 2025-02-20
DOI: 10.3390/aerospace12030170
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 171: Influence of Vertical/Spanwise Offsets on
Aerodynamic Performance of Double Serpentine Nozzles
Authors: Xuyong Zhang, Yong Shan, Jingzhou Zhang
First page: 171
Abstract: Serpentine exhaust systems, known for their infrared and radar stealth capabilities, are becoming standard in flying wing aircraft. However, their design is constrained by the fuselage layout, causing potential offsets between the engine and nozzle exit axes. Developing a universal, high-performance serpentine nozzle design that accommodates various vertical and spanwise offsets (ΔZ, ΔY) presents a significant challenge. A series of ‘Preferred Nozzles’ and ‘Modest Nozzles’ were designed and numerically evaluated to assess the impact of these offsets on flow characteristics. Results show that the ‘Modest Nozzle’ exhibits a complex wave system and significant local losses in the constant-area extension section when subjected to ΔZ > 0.10D0 (D0 is the nozzle inlet diameter) or ΔY > 1.0D0, leading to a rapid thrust coefficient decrease. Vertical offsets significantly affect the Preferred Nozzle’s aerodynamic performance. When ΔZ = −0.50D0, a large vertical offset in the first ‘S’ section creates a recirculation zone, causing significant losses and reducing the thrust coefficient to around 0.96. When ΔZ ≥ −0.25D0, gas flow and wall shear stress distributions transition smoothly. When ΔZ ≥ 0.10D0, as the spanwise offset increases, the thrust coefficient experiences only a 0.17% loss and remains above 0.97.
Citation: Aerospace
PubDate: 2025-02-21
DOI: 10.3390/aerospace12030171
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 172: Design and Analysis of a
Micro–Electro-Mechanical System Thruster for Small Satellites and
Low-Thrust Propulsion
Authors: Yubin Zhong, Fabrizio Ponti, Francesco Barato, Guojun Xia, Siyu Li, Xiao Zhang, Tao Wu
First page: 172
Abstract: As a cost-effective and versatile solution, small satellites are increasingly being considered for space exploration. However, one of the major challenges in deploying small satellites for high total impulse missions, particularly deep space exploration, lies in the propulsion system. These missions face strict constraints in terms of volume, mass, and power budgets. This paper proposes a potential solution to this issue through the design of a bipropellant MEMS thruster. Simulation results indicate that this type of thruster offers superior performance compared to the monopropellant propulsion systems typically used in small satellite missions. Specifically, the bipropellant MEMS thruster demonstrates enhanced specific impulse and thrust-to-weight ratio, making it a promising alternative for small satellite propulsion in high total impulse missions.
Citation: Aerospace
PubDate: 2025-02-21
DOI: 10.3390/aerospace12030172
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 173: Comprehensive Numerical Analysis of Mixing
Characteristics in a Scramjet Combustor Utilizing Multi-Pylon
Configurations
Authors: Xuefeng Xia, Zhensheng Sun, Yingyang Wang, Yu Hu, Hongfu Qiang, Yujie Zhu, Yin Zhang
First page: 173
Abstract: The pylon has been identified as a highly promising method for enhancing mixing efficiency in scramjet combustors. This work systematically assessed the impact of spanwise, streamwise, and oblique multi-pylon combinations in a supersonic cold flow through numerical simulations, employing pylon-aided ethylene fuel injection under low dynamic pressure conditions. The Reynolds-averaged Navier–Stokes (RANS) equations with the SST k-ω turbulence model are applied during the simulation. Numerical results reveal that, in comparison to the streamwise combination, the spanwise combination exhibits superior flow field characteristics in terms of mixing efficiency, penetration depth, and total pressure loss. For a given injection condition, an optimal distance between pylons exists in the spanwise combination, with the angle between two pylons having minimal influence on mixing efficiency. The oblique multi-pylon combination yields poorer mixing enhancement efficiency and fuel penetration but incurs less total pressure loss in the near field when compared to the spanwise combination. Additionally, the oblique multi-pylon combination demonstrates enhanced mixing efficiency further downstream of the injector than the spanwise combination. This investigation into fuel injection schemes based on multi-pylon combinations offers valuable insights for the structural design of scramjet engines.
Citation: Aerospace
PubDate: 2025-02-21
DOI: 10.3390/aerospace12030173
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 174: Analysis of Flutter Characteristics for
Composite Laminates in Hypersonic Yawed Flow
Authors: Shuang Cao, Tongqing Guo, Jiangpeng Wu, Di Zhou, Ennan Shen
First page: 174
Abstract: This paper investigates the flutter characteristics of composite laminates in hypersonic yawed flow using numerical simulations. The governing equations are derived based on Hamilton’s principle and were discretized using the assumed mode method. The unsteady aerodynamic force is calculated by using the piston theory, including the influence of the yaw angle. Several laminate models are designed to study the effects of the stacking sequence, thickness ratio, and fiber orientation on the critical dynamic pressure and the amplitude of the limit cycle oscillation. Numerical results show that positioning the material with higher stiffness on the upper layer can lead to a higher critical dynamic pressure and a smaller amplitude of the limit cycle oscillation. In the case of large yaw angles, increasing the thickness of the material with larger stiffness can clearly suppress the amplitude of the limit cycle oscillation. Fiber orientation symmetry to the x-axis can improve the flight stability with the change in the yaw angle.
Citation: Aerospace
PubDate: 2025-02-21
DOI: 10.3390/aerospace12030174
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 175: New Method for Improving Tracking Accuracy
of Aero-Engine On-Board Model Based on Separability Index and Reverse
Searching
Authors: Hui Li, Yingqing Guo, Xinyu Ren
First page: 175
Abstract: Throughout its service life, an aero-engine will experience a series of health conditions due to the inevitable performance degradation of its major components, and characteristics will deviate from their initial states. For improving tracking accuracy of the self-tunning on-board engine model on the engine output variables throughout the engine service life, a new method based on the separability index and reverse search algorithm was proposed in this paper. By using this method, a qualified training set of neural networks was created on the basis of eSTORM (enhanced Self Tuning On-board Real-time Model) database, and the problem that the accuracy of neural networks is reduced or even that the training process is not convergent can be solved. Compared with the method of introducing sample memory factors, the method proposed in this paper makes the self-tunning on-board model maintain higher tracking accuracy in the whole engine life, and the algorithm is simple enough for implementation. Finally, the training set center generated in the calculation process of the proposed method could be used for the real-time monitoring of the engine gas path parameters without additional calculations. Compared with the commonly used sliding window method, the proposed method avoids the problem of low algorithm efficiency caused by fewer abnormal data samples.
Citation: Aerospace
PubDate: 2025-02-22
DOI: 10.3390/aerospace12030175
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 176: Parametric Simulation Study of Liquid Film
Cooling of Hydrocarbon Liquid Rocket Engine
Authors: Huixin Yang, Haoyu Zou, Zeming Song, Wenhao Yu
First page: 176
Abstract: The hydrocarbon liquid rocket engine working environment is harsh; the thrust chamber needs to withstand high temperatures and a high-pressure working environment, and the thrust chamber wall material is difficult to bear, so it is necessary to design the cooling structure to reduce the gas damage to the chamber wall. Liquid film cooling is a common cooling method for hydrocarbon rocket engines, and numerical simulation is an important method for studying liquid film cooling. Most of the liquid film cooling numerical simulation is for a fixed model. This paper proposes a liquid film cooling numerical calculation method for a variable-configuration hydrocarbon liquid rocket engine, based on the secondary development of Fluent software(ANSYS Fluent 2022) to form a high-energy hydrocarbon liquid rocket engine design software, which can be realized on the Qt platform. The visualization interface can be for different engine injection port locations, numbers, angles, mass flow rates, and other parameters, to calculate and improve design efficiency and reduce operating difficulty.
Citation: Aerospace
PubDate: 2025-02-22
DOI: 10.3390/aerospace12030176
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 177: ARC-LIGHT: Algorithm for Robust
Characterization of Lunar Surface Imaging for Ground Hazards and
Trajectory
Authors: Alexander Cushen, Ariana Bueno, Samuel Carrico, Corrydon Wettstein, Jaykumar Ishvarbhai Adalja, Mengxiang Shi, Naila Garcia, Yuliana Garcia, Mirko Gamba, Christopher Ruf
First page: 177
Abstract: Safe and reliable lunar landings are crucial for future exploration of the Moon. The regolith ejected by a lander’s rocket exhaust plume represents a significant obstacle in achieving this goal. It prevents spacecraft from reliably utilizing their navigation sensors to monitor their trajectory and spot emerging surface hazards as they near the surface. As part of NASA’s 2024 Human Lander Challenge (HuLC), the team at the University of Michigan developed an innovative concept to help mitigate this issue. We developed and implemented a machine learning (ML)-based sensor fusion system, ARC-LIGHT, that integrates sensor data from the cameras, lidars, or radars that landers already carry but disable during the final landing phase. Using these data streams, ARC-LIGHT will remove erroneous signals and recover a useful detection of the surface features to then be used by the spacecraft to correct its descent profile. It also offers a layer of redundancy for other key sensors, like inertial measurement units. The feasibility of this technology was validated through development of a prototype algorithm, which was trained on data from a purpose-built testbed that simulates imaging through a dusty environment. Based on these findings, a development timeline, risk analysis, and budget for ARC-LIGHT to be deployed on a lunar landing was created.
Citation: Aerospace
PubDate: 2025-02-24
DOI: 10.3390/aerospace12030177
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 178: Structural Optimization and Experimental
Validation of a Composite Engine Mount Designed for VTOL UAV
Authors: Milica Milić, Jelena Svorcan, Toni Ivanov, Ivana Atanasovska, Dejan Momčilović, Željko Flajs, Boško Rašuo
First page: 178
Abstract: Unmanned air vehicles (UAVs) with vertical take-off and landing (VTOL) capabilities, equipped with rotors, have been gaining popularity in recent years for their numerous applications. Through joint efforts, engineers and researchers try to make these novel aircraft more maneuverable and reliable, but also lighter, more efficient and quieter. This paper presents the optimization of one of the vital aircraft parts, the composite engine mount, based on the genetic algorithm (GA) combined with the defined finite element (FE) parameterized model. The mount structure is assumed as a layered carbon composite whose lay-up sequence, defined by layer thicknesses and orientations, is being optimized with the goal of achieving its minimal mass with respect to different structural constraints (failure criteria or maximal strain). To achieve a sufficiently reliable structure, a worst-case scenario, representing a sudden impact, is assumed by introducing forces at one end, while the mount is structurally constrained at the places where it is connected to wings. The defined optimization methodology significantly facilitated and accelerated the mount design process, after which it was manufactured and experimentally tested. Static forces representing the two thrust forces generated by the propellers connected to electric engines (at 100% throttle and the asymmetric case where one engine is at approximately 40% throttle and the other at 100%) and loads from the tail surfaces were introduced by weights, while the strain was measured at six different locations. Satisfactory comparison between numerical and experimental results is achieved, while slight inconsistencies can be attributed to manufacturing errors and idealizations of the FE model.
Citation: Aerospace
PubDate: 2025-02-24
DOI: 10.3390/aerospace12030178
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 179: Shear Stress Distribution of the Separation
Region on a Plate in Supersonic Jet Flow
Authors: Yun Jiao, Weijun Li, Yu Ji, Puchen Hou, Ye Yuan, Longsheng Xue, Keming Cheng, Chengpeng Wang
First page: 179
Abstract: An experimental study is conducted on the surface shear stress vector distribution on a plate in a supersonic jet flow, with a focus on the separation region. The shear-sensitive liquid crystal coating (SSLCC) technique is employed for the flow visualization and measurement, which is based on the shear stress distribution, and the flow pattern on the plate is captured. The results demonstrate that the nozzle pressure ratio (NPR) is the main inducement to flow evolution, and a high NPR causes a separation region on the plate, where the adverse flow is challenging to the SSLCC technique. Therefore, an improved measurement method for the SSLCC is proposed to successfully obtain the wall shear stress distribution inside the separation and reattachment area. The flow structures on the plate, including the separation and reattachment positions and vortex and adverse flows, are accurately captured in detail, which indicates that this method is practical for measuring the wall shear stress in separated flow.
Citation: Aerospace
PubDate: 2025-02-24
DOI: 10.3390/aerospace12030179
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 180: Airfoil Optimization and Analysis Using
Global Sensitivity Analysis and Generative Design
Authors: Pablo Rouco, Pedro Orgeira-Crespo, Guillermo David Rey González, Fernando Aguado-Agelet
First page: 180
Abstract: This research investigates the optimization of airfoil design for fixed-wing drones, aiming to enhance aerodynamic efficiency and reduce drag. The research employs Kulfan CST and Bézier surface parameterization methods combined with global sensitivity analysis (GSA) and machine learning techniques to improve airfoil performance under various operational conditions. Particle swarm optimization (PSO) is utilized to optimize the airfoil design, minimizing drag in cruise and ascent conditions while ensuring lift at takeoff. Computational fluid dynamics (CFD) simulations, primarily using XFOIL, validate the aerodynamic performance of the optimized airfoils. This study also explores the generative design approach using a neural network trained on 10 million airfoil simulations to predict airfoil geometry based on desired performance criteria. The results show important improvements in drag reduction, especially during low-speed cruise and ascent phases, contributing to extended flight endurance and efficiency. These results can be used for small unmanned aerial vehicles (UAVs) in real-world applications to develop better-performance UAVs under mission-specific constraints.
Citation: Aerospace
PubDate: 2025-02-24
DOI: 10.3390/aerospace12030180
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 181: Characterization of a Fragmentation in a
Highly Elliptical Orbit via an Optical Multi-Observatory Survey Strategy
Authors: Matteo Rossetti, Lorenzo Cimino, Lorenzo Mariani, Simone Varanese, Gaetano Zarcone, Elisa Maria Alessi, Alessandro Rossi, Alessandro Nastasi, Carmelo Arcidiacono, Simone Zaggia, Matteo Simioni, Alfredo Biagini, Alessandra Di Cecco, Fabrizio Piergentili
First page: 181
Abstract: Surveys of fragmentations, especially in the early stages of the given event, are fundamental for determining the number of fragments, identifying and cataloging them, and monitoring their future evolution. The development of a ground-based optical survey strategy, i.e., a suitable observation and detection method for the fragments generated by these events, is an important contribution to acquiring data and monitoring these catastrophic phenomena. An optical survey offers an interesting and cost-effective method that supports radar operations in the Low Earth Orbit regime and can monitor higher orbits where radar cannot be used. This paper presents a developed optical survey strategy for multi-observatory observations. The strategy was tested on the fragmentation event of FREGAT R/B CLUSTER 2, a rocket body with a “dummy” payload, fragmented on 8 April 2024 on a Highly Elliptical Orbit. The observational campaign involved different observatory systems, and it represented a key collaboration within the Inter-Agency Space Debris Coordination Committee. The survey started from a simulation of the cloud of fragments and was implemented by the planification and coordination of different observatory systems with different schemes and methods to scan the sky vault. The acquired survey data were analyzed using machine learning methods to identify the unknown objects, i.e., the fragments. The data acquired were compared with the simulated cloud used for the survey, and a correlation of measurements belonging to the same object was performed. Also, the parent body was characterized in its tumbling motion by the light curve acquisition.
Citation: Aerospace
PubDate: 2025-02-25
DOI: 10.3390/aerospace12030181
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 182: Effects of Primary Jets on the Flow Field
and Outlet Temperature Distribution in a Reverse-Flow Combustor
Authors: Qian Yao, Peixing Li, Chaoqun Ren, Chaowei Tang, Qiongyao Qin, Jianzhong Li, Wu Jin
First page: 182
Abstract: A reverse-flow combustor has a larger liner surface area due to airflow turning, which complicates flow and cooling control, particularly heat transfer efficiency. Effective heat management is essential for maintaining uniform temperature distribution and preventing thermal gradients. This study explores the impact of axial position and diameter of primary holes on thermal performance and flow dynamics. Results indicate that as the primary holes move toward the dome, the recirculation vortex size decreases, leading to insufficient fuel mixing, a reduction in the high-temperature area in the primary zone, and an increase in the high-temperature area of the middle zone. On the other hand, moving the primary holes downstream enhances fuel mixing, increasing high-temperature areas in the primary zone and reducing them in the middle and dilution zones, thus improving thermal boundary layers and convective heat transfer rates. When the primary hole is moved 10 mm downstream, outlet temperature improves significantly with an outlet temperature distribution factor (OTDF) of 0.21 and a radial temperature distribution factor (RTDF) of 0.16. Additionally, reducing the upper primary hole diameter strengthens jet deflection, improving fuel–gas mixing at the dome and heat transfer to the central region. With a 2.1 mm hole diameter, the temperature gradient decreases, resulting in an OTDF of 0.184 and RTDF of 0.15. Furthermore, as the momentum flux ratio increases, the jet penetration depth initially rises and then stabilizes. Momentum flux ratios between 10.6 and 15.1 significantly affect jet penetration, while further increases result in smaller fluctuations. Higher momentum flux ratios create localized high- and low-temperature zones, reducing outlet temperature distribution quality. The optimal momentum ratio for the reverse-flow combustor, ensuring effective jet penetration and better temperature distribution, is between 10.6 and 14.7, with a corresponding penetration depth of 34.3 mm to 35.1 mm. These findings offer valuable insights for improving reverse-flow combustor design and performance.
Citation: Aerospace
PubDate: 2025-02-25
DOI: 10.3390/aerospace12030182
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 183: Minimum-Fuel Trajectories and Near-Optimal
Explicit Guidance for Pinpoint Landing from Low Lunar Orbit
Authors: Matteo Caruso, Giulio De Angelis, Edoardo Maria Leonardi, Mauro Pontani
First page: 183
Abstract: This research addresses minimum-fuel pinpoint lunar landing at the South Pole, focusing on trajectory design and near-optimal guidance aimed at driving a spacecraft from a circular low lunar orbit (LLO) to an instantaneous hovering state above the lunar surface. Orbit dynamics is propagated in a high-fidelity ephemeris-based framework, which employs spherical coordinates as the state variables and includes several harmonics of the selenopotential, as well as third-body gravitational perturbations due to the Earth and Sun. Minimum-fuel two-impulse descent transfers are identified using Lambert problem solutions as initial guesses, followed by refinement in the high-fidelity model, for a range of initial LLO inclinations. Then, a feedback Lambert-based impulsive guidance algorithm is designed and tested through a Monte Carlo campaign to assess the effectiveness under non-nominal conditions related to injection and actuation errors. Because the last braking maneuver is relatively large, a finite-thrust, locally flat, near-optimal guidance is introduced and applied. Simplified dynamics is assumed for the purpose of defining a minimum-time optimal control problem along the last thrust arc. This admits a closed-form solution, which is iteratively used until the desired instantaneous hovering condition is reached. The numerical results in non-nominal flight conditions testify to the effectiveness of the guidance approach at hand in terms of propellant consumption and precision at landing.
Citation: Aerospace
PubDate: 2025-02-25
DOI: 10.3390/aerospace12030183
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 184: Exact Separation of Purely Short-Period
Effects and Mean Variations in the Main Problem of Artificial Satellite
Theory
Authors: Martin Lara
First page: 184
Abstract: It is well known that mean elements obtained by canonical perturbation theory only agree partially with the average dynamics of the osculating orbit. While this fact does not necessarily compromise the accuracy of corresponding perturbation solutions, the loose use of the terminology “mean elements” in artificial satellite theory may obscure the understanding of the variety of available solutions in the literature, and thus make the implementation of additional patches to increase their performance ambiguous. We resort to noncanonical perturbation methods, and, for the main problem of artificial satellite theory (the J2-problem), compute the purely periodic, noncanonical, mean-to-osculating transformation that yields the exact separation between short- and long-period variations up to the second order of the zonal harmonic of the second degree. To our knowledge this transformation is new and was long-awaited by software developers in order to improve operational orbit propagation tools based on semianalytical integration. It is also shown that this kind of noncanonical solution confines the long-period oscillations of the semimajor axis in the mean variation equations.
Citation: Aerospace
PubDate: 2025-02-25
DOI: 10.3390/aerospace12030184
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 185: Results from the ATS-Level Assessment of
the Clean Sky 2 Technology Evaluator
Authors: Marc C. Gelhausen, Alf Junior, Alexandra Leipold, Peter Berster, Holger Pabst, Christos Lois, Fabian Baier
First page: 185
Abstract: In this paper, we present the main results from the Second ATS-Level Assessment of the Clean Sky 2 Technology Evaluator. We first present the models employed and then move to the passenger and fleet forecast results up to 2050. Based upon these traffic forecasts, we show the environmental effect of Clean Sky 2 technology in terms of CO2 emissions. The main benefit of the forecast method employed is its high resolution in terms of each flight route between airports being modelled. Consequently, we can consider effects such as airport capacity constraints which will have a substantial impact on future passenger volume and fleet development.
Citation: Aerospace
PubDate: 2025-02-26
DOI: 10.3390/aerospace12030185
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 186: Deployment of a Testbed for Validation of
TSN Networks in Avionics
Authors: Laura Castro-Lara, Pablo Vera-Soto, Sergio Fortes, Vicente Escaño, Rafael Ortiz, Raquel Barco
First page: 186
Abstract: Time-Sensitive Networking (TSN) in avionics is being considered as a standard capable of providing more real-time and safety-critical capabilities than AFDX, the current standard in avionics communications. A TSN profile is therefore being developed for the aerospace domain by IEEE. Hence, this research outlines the deployment of a testbed aimed at validating TSN in avionics to ensure that this technology meets the stringent timing and latency requirements of avionics applications. To this end, a daisy chain or ring topology has been set up for the validation of the testbed, as this topology provides redundancy of paths without the need to add additional devices. This work presents latency and jitter measurements under different priority configurations and different channel saturation conditions, showing no packet loss and demonstrating the reliability of TSN for time-critical applications. A comparison with Avionics Full Duplex Ethernet (AFDX) simulations was also made, highlighting the weaknesses of AFDX. By providing a comprehensive platform for testing and validation, the testbed will contribute to the advancement of TSN technology in aerospace applications, ultimately improving the safety and efficiency of aircraft operations.
Citation: Aerospace
PubDate: 2025-02-26
DOI: 10.3390/aerospace12030186
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 187: Three-Dimensional Numerical Investigation
of the Asymmetric Discard Characteristics of Hypervelocity Projectile
Sabot
Authors: Xuefeng Yang, Junyong Lu, Bai Li, Sai Tan, Zhiqiang Xie
First page: 187
Abstract: Sabots are vital to the successful launch of hypervelocity projectiles (HVPs), supporting and protecting the projectile’s flight body within the barrel. After the projectile exits the muzzle, aerodynamic forces induce relative motion between the sabot and the flight body, termed ‘sabot discard’. During this process, there are complex aerodynamic interactions between the sabot and flight body. These interactions impact the flight body’s flight stability and accuracy. This research focuses on an HVP with a two-segment sabot at Mach 7.2, employing the unstructured overset grid method and three-degree-of-freedom model to investigate the impact of the angle of attack (AOA) on the discard. At the AOA = 0 Deg, the sabot segments’ movement is symmetric, causing fluctuations in the flight body’s drag. However, at AOAs ≠ 0 Deg, the sabot segments’ movement becomes asymmetric. The upper sabot segment accelerates while the lower one decelerates, causing significant fluctuations in drag and lift, and prolonged disturbance. As the AOA increases, both asymmetry and disturbances intensify. Notably, at the AOA = 8 Deg, the absolute value of the discard angle difference between the upper and lower sabot segments reaches 45 Deg. Considering the AOA’s impact, it is advisable to maintain the AOA for HVP sabot discard in the range of [−2, 2] Deg.
Citation: Aerospace
PubDate: 2025-02-26
DOI: 10.3390/aerospace12030187
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 188: Test Results for a Novel 20 kW Two-Phase
Pumped Cooling System for Aerospace Applications
Authors: Henk Jan van Gerner, Tim Luten, Sigurd Scholten, Georg Mühlthaler, Marcus-Benedict Buntz
First page: 188
Abstract: In the EU-funded BRAVA project, technologies for a fuel cell-based power generation system for aviation are being developed. In this paper, the test results for a demonstrator of a novel two-phase pumped cooling system with 20 kW cooling capacity are presented. This system uses the evaporation of a liquid to remove waste heat from the heat sources. Several concepts have been tested with this demonstrator, including the ‘no accumulator’ concept, which offers a large mass reduction compared to conventional cooling systems. Additionally, the system can be rotated, and the influence of the orientation has been tested.
Citation: Aerospace
PubDate: 2025-02-26
DOI: 10.3390/aerospace12030188
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 189: Experimental Evaluation of Multi- and
Single-Drone Systems with 1D LiDAR Sensors for Stockpile Volume Estimation
Authors: Ahmad Alsayed, Fatemeh Bana, Farshad Arvin, Mark K. Quinn, Mostafa R. A. Nabawy
First page: 189
Abstract: This study examines the application of low-cost 1D LiDAR sensors in drone-based stockpile volume estimation, with a focus on indoor environments. Three approaches were experimentally investigated: (i) a multi-drone system equipped with static, downward-facing 1D LiDAR sensors combined with an adaptive formation control algorithm; (ii) a single drone with a static, downward-facing 1D LiDAR following a zigzag trajectory; and (iii) a single drone with an actuated 1D LiDAR in an oscillatory fashion to enhance scanning coverage while following a shorter trajectory. The adaptive formation control algorithm, newly developed in this study, synchronises the drones’ waypoint arrivals and facilitates smooth transitions between dynamic formation shapes. Real-world experiments conducted in a motion-tracking indoor facility confirmed the effectiveness of all three approaches in accurately completing scanning tasks, as per intended waypoints allocation. A trapezoidal prism stockpile was scanned, and the volume estimation accuracy of each approach was compared. The multi-drone system achieved an average volumetric error of 1.3%, similar to the single drone with a static sensor, but with less than half the flight time. Meanwhile, the actuated LiDAR system required shorter paths but experienced a higher volumetric error of 4.4%, primarily due to surface reconstruction outliers and common LiDAR bias when scanning at non-vertical angles.
Citation: Aerospace
PubDate: 2025-02-26
DOI: 10.3390/aerospace12030189
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 190: A Design Guide to Tapered Conformable
Pressure Tanks for Liquid Hydrogen Storage
Authors: Joren Malfroy, Johan Steelant, Dirk Vandepitte
First page: 190
Abstract: Liquid hydrogen has the potential to significantly reduce in-flight carbon emissions in the aviation industry. Among the most promising aircraft configurations for future hydrogen-powered aviation are the blended wing body and the pure flying wing configurations. However, their tapered and flattened airframe designs pose a challenge in accommodating liquid hydrogen storage tanks. This paper presents a design guide to tapered conformable pressure tanks for liquid hydrogen storage. The proposed tank configurations feature a multi-bubble layout and are subject to low internal differential pressure. The objective is to provide tank designers with simple geometric rules and practical guidelines to simplify the design process of tapered multi-bubble pressure tanks. Various tank configurations are discussed, starting with a simple tapered two-bubble tank and advancing to more complex tapered configurations with a multi-segment and multi-bubble layout. A comprehensive design methodology is established, providing tank designers with a step-by-step design procedure and highlighting the practical guidelines in each step of the design process.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030190
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 191: A Relative Attitude Detection Method for
Unmanned Aerial Vehicles Based on You Only Look Once Framework
Authors: Jingting Qiu, Feifan Yu, Fengrui Xu, Xinmin Chen, Jiqiang Wang
First page: 191
Abstract: Variable environments and constrained edge devices pose the significantly challenging task of directly recognizing the relative attitude of unmanned aerial vehicles (UAVs). Furthermore, datasets of UAV landing markers that are accessible to the general public are scarce. To tackle these challenges, we first constructed a dataset on UAV landing markers called the UAV landing marker dataset (ULMD). Then, we enhanced the You Only Look Once (YOLO) model to devise a model specifically tailored for directly recognizing the relative attitude of UAVs, termed UAV relative attitude YOLO (URA-YOLO). Within URA-YOLO, we propose an enhanced multiscale feature fusion (EMF) module that increases the network’s perceptual range and extracts feature information corresponding to various image sizes. Additionally, we propose a lightweight and efficient feature extraction (LE) module to acquire high-dimensional semantic information. Finally, to mitigate background noise interference, we propose an efficient layer aggregation network with convolutional block attention (ELAN-CA) module. The experimental results demonstrate that our model outperforms the baseline by 10.8% in terms of accuracy while occupying a mere 5.8 M in size, representing a reduction of 6.5%, achieving a satisfactory balance between performance and resource consumption.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030191
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 192: Application of a Soft-Switching Adaptive
Kalman Filter for Over-Range Measurements in a Low-Frequency Extension of
MHD Sensors
Authors: Junze Tong, Shaocen Shi, Fuchao Wang, Dapeng Tian
First page: 192
Abstract: The increasing demand for image quality in aerospace remote sensing has led to higher performance requirements for inertial stabilization platforms equipped with image sensors, particularly in terms of bandwidth. To achieve wide-bandwidth control in optical stabilization platforms, engineers employ magneto-hydrodynamic (MHD) sensors as key components to enhance system performance because of their wide measurement bandwidth (5–1000 Hz). While MHD sensors offer a wide-frequency response, they are limited by a narrow measuring range and low sensitivity at low frequencies, making them unsuitable as standalone sensors. To address the challenges of over-range measurement and the loss of low-frequency signals, in this study, we developed a soft-switching adaptive Kalman filter method, which enables us to dynamically adjust the fusion weights in the Kalman filter so we can obtain wide-band measurement signals even when the MHD sensor experiences over-range conditions. The proposed method was validated with fusion experiments involving a fiber-optic gyroscope and an MHD sensor; the results demonstrate its ability to expand the sensing bandwidth, regardless of the operating conditions of the MHD sensor.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030192
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 193: Tactical Coordination-Based Decision Making
for Unmanned Combat Aerial Vehicles Maneuvering in Within-Visual-Range Air
Combat
Authors: Yidong Liu, Dali Ding, Mulai Tan, Yuequn Luo, Ning Li, Huan Zhou
First page: 193
Abstract: Targeting the autonomous decision-making problem of unmanned combat aerial vehicles (UCAVs) in a two-versus-one (2v1) within-visual-range (WVR) air combat scenario, this paper proposes a maneuver decision-making method based on tactical coordination. First, a coordinated situation assessment model is designed, which subdivides the air combat situation into optimization-driven and tactical coordinated situations. The former combines missile attack zone calculation and trajectory prediction to optimize the control quantity of a single aircraft, while the latter uses fuzzy logic to analyze the overall situation of the three aircraft to drive tactical selection. Second, a decision-making model based on a hierarchical expert system is constructed, establishing a hierarchical decision-making framework with a UCAV-coordinated combat knowledge base. The coordinated situation assessment results are used to match corresponding tactics and maneuver control quantities. Finally, an improved particle swarm optimization algorithm (I-PSO) is proposed, which enhances the optimization ability and real-time performance through the design of local social factor iterative components and adaptive adjustment of inertia weights. Air combat simulations in four different scenarios verify the effectiveness and superiority of the proposed decision-making method. The results show that the method can achieve autonomous decision making in dynamic air combat. Compared with decision-making methods based on optimization algorithms and differential games, the win rate is increased by about 17% and 18%, respectively, and the single-step decision-making time is less than 0.02 s, demonstrating high real-time performance and win rate. This research provides new ideas and methods for the autonomous decision making of UCAVs in complex air combat scenarios.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030193
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 194: DeepAF: Transformer-Based Deep Data
Association and Track Filtering Network for Multi-Target Tracking in
Clutter
Authors: Yaqi Cui, Pingliang Xu, Weiwei Sun, Shaoqing Zhang, Jiaying Li
First page: 194
Abstract: Based on the transformer model, a deep data association and track filtering network (DeepAF) was constructed in this paper to achieve the function of data association and end-to-end track filtering. Combined with the existing track initiation methods, DeepAF can be used to track multiple targets in clutter environments. Experimental results show that DeepAF can stably and effectively track targets moving in different models such as constant velocity, constant acceleration, and constant turn rate. Compared with the probability hypothesis density filter and the probabilistic data association method, which were set with different state transition matrices manually to match with the actual target motion models, DeepAF has similar estimation accuracy in respect of target velocity and better estimation accuracy in respect of target position with less time consumption. For position estimation, compared with PHD, DeepAF can reduce the estimation error by 49.978, 49.263, and 2.706 m in the CV, CA, and CT motion models. Compared with PDA, DeepAF can reduce the estimation error by 13.465, 23.98, and 4.716 m in CV, CA, and CT motion models. For time consumption, compared with PHD, DeepAF can reduce the time by 991.2, 982.3, and 979.5 s in CV, CA, and CT motion models. Compared with PDA, DeepAF can reduce the time by 61.6, 60.5, and 61.4 s in CV, CA, and CT motion models.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030194
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 195: Neural Network-Aided Optical Navigation for
Precise Lunar Descent Operations
Authors: Simone Andolfo, Antonio Genova, Fabio Valerio Buonomo, Anna Maria Gargiulo, Mohamed El Awag, Pierluigi Federici, Riccardo Teodori, Riccardo La Grassa, Cristina Re, Gabriele Cremonese
First page: 195
Abstract: Advanced navigation capabilities are essential for precise landing operations, enabling access to critical lunar sites and supporting future lunar infrastructure. To achieve accurate positioning, innovative navigation methods leveraging neural network frameworks are being developed to detect distinctive lunar surface features, such as craters, from imaging data. By matching detected features with known landmarks stored in an onboard reference database, key navigation measurements are retrieved to refine the spacecraft trajectory, enabling real-time planning for hazard avoidance. This work presents a crater-based navigation system for planetary descent operations, which leverages a robust machine learning approach for crater detection in optical images. A thorough analysis of the attainable detection accuracies was performed by evaluating the network performance on diverse sets of synthetic images rendered at different illumination conditions through a custom Blender-based pipeline. Simulation campaigns, based on the JAXA Smart Lander for Investigating Moon mission, were then carried out to demonstrate the system’s performance, achieving final position errors consistent with 3 −σ uncertainties lower than 100 m on the horizontal plane at altitudes as low as 10 km. This level of accuracy is key to achieving enhanced control during the approach and vertical descent phases, thereby ensuring operational safety and facilitating precise landing.
Citation: Aerospace
PubDate: 2025-02-27
DOI: 10.3390/aerospace12030195
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 196: An Initial Trajectory Design for the
Multi-Target Exploration of the Electric Sail
Authors: Zichen Fan, Fei Cheng, Wenlong Li, Guiqi Pan, Mingying Huo, Naiming Qi
First page: 196
Abstract: The electric sail (E-sail), as an emerging propulsion system with an infinite specific impulse, is particularly suitable for ultra-long-distance multi-target deep-space exploration missions. If multiple gravity assists are considered during the exploration process, it can effectively improve the exploration efficiency of the E-sail. This paper proposes a fast optimization algorithm for deep-space multi-target exploration trajectories for the E-sail, which achieves the exploration of multiple celestial bodies and solar-system boundaries in one flight, and introduces a gravity assist to improve the flight speed of the E-sail during the exploration process. By comparing simulation examples under different conditions, the effectiveness of the algorithm proposed in this paper has been demonstrated. This is of great significance for the initial rapid design of complex deep-space exploration missions such as the E-sail multi-target exploration.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030196
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 197: Numerical Simulation of Self-Sustained Roll
Oscillations of an 80-Degree Delta Wing Caused by Leading-Edge Vortices
Authors: Mohamed Sereez, Mikhail Goman, Nikolay Abramov, Caroline Lambert
First page: 197
Abstract: Numerical simulations of an 80-degree delta wing in free-to-roll motion are performed by applying the dynamic fluid–body interaction (DFBI) model and the overlap/chimera method using the URANS equations. The capabilities of modern computational fluid dynamics methods for predicting wing-rock phenomena over a wide range of angles of attack at low Mach numbers and strong wing–vortex interaction, including the vortex breakdown phenomenon, were investigated by comparing simulation results with wind tunnel test data. At low angles of attack, delays in the strength and position of the leading-edge vortices above the wing have a destabilizing effect on it, leading to the emergence of self-sustained limit-cycle oscillations. At high angles of attack, where vortex breakdown occurs, the available wind tunnel data show that there are two modes of wing self-oscillations in free-to-roll motion, namely, regular large-amplitude oscillations and irregular small-amplitude oscillations, where the excitation of the latter mode depends on the angle of attack and the initial roll angle of the wing motion. The performed numerical simulation also shows the existence of these two self-oscillatory modes in roll, qualitatively and quantitatively matching the experimental data.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030197
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 198: Active Flow Control Technology Based on
Simple Droop Devices and a Co-Flow Jet for Lift Enhancement
Authors: Jin Jiao, Cheng Chen, Bo Wang, Pei Ying, Qiong Wei, Shengyang Nie
First page: 198
Abstract: The missions of modern aircraft require multiple abilities, such as highly efficient taking-off and landing, fast arrival, and long-endurance hovering. It is difficult to achieve all technical objectives using traditional aircraft design technology. The active flow control technology using the concept of a co-flow jet (CFJ) is a flow control method without a mass source that does not require air from the engine. It has strong flow control ability in low-speed flow, can greatly improve the stall angle of the aircraft, and can obtain large lift enhancement. At transonic conditions, it can lead to a larger lift–drag ratio with a small expense. CFJ technology has great application potential for aircraft due to its flexible control strategy and remarkable control effect. In this paper, the concept of a combination of CFJ and variable camber technology is proposed which realizes the change of airfoil camber to meet different task requirements with the movable droop head. By using the built-in ducted fan, air is blown and sucked in the jet channel so as to realize CFJ flow control. In a state of high-speed flight, complete geometric restoration is achieved by closing the channel and retracting the droop head. In this paper, the design and aerodynamic analysis of a CFJ device with variable camber based on a supercritical airfoil with small camber and a small leading-edge radius are carried out using the computational fluid dynamics (CFD) method. Comparative studies are conducted for different schemes on the taking off and landing performances, and discussions are had on core technical parameters such as power consumption. The results indicate that by utilizing the CFJ technology with more than 10 degrees of droop device, the maximum lift coefficient of a supercritical airfoil with a small camber and leading-edge radius, which is suitable for transonic flight, can be increased to a value larger than 4.0.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030198
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 199: A Sample Average Approximation Approach for
Aircraft Product Configuration Optimization with Customer Order
Uncertainty
Authors: Xinyuan Zhang, Kejun Qiu, Bo Niu, Lu Chen, Juntong Xi
First page: 199
Abstract: Commercial aircraft manufacturers often face order uncertainty in particular situations, such as quantity or demand change, or lack of confirmed customer options. As a countermeasure, aircraft manufacturers can adopt a two-stage strategy to produce batch General-Configuration Aircraft (GCA), so as to maintain continuous aircraft production. Nevertheless, additional work on disassembling and re-assembling must be performed, to convert the GCA into specific configurations specified later by the customer. Thus, an appropriate GCA that leads to a minimal overall manufacturing workload is essential. In this paper, a Sample Average Approximation (SAA) model for GCA optimization is proposed, to obtain a robust GCA whose prediction results can help minimize the total production time. Compared with the empirical method, the proposed SAA approach significantly accelerates the production operation and is adaptive to various scenarios. The robustness of the SAA approach was evaluated, and the results prove that the general configuration obtained by the SAA approach has sustainable variances in the manufacturing workload.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030199
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 200: A Two-Dimensional Analysis of the Flowfield
and Performances of Linear Aerospikes During Differential Throttling
Authors: Jehangir Hassan, Gaetano Maria Di Cicca, Michele Ferlauto, Roberto Marsilio, Emanuele Resta
First page: 200
Abstract: The performances of two linear aerospike nozzles, generated by truncating the same plug contour at 40% and 20% of its ideal length, are investigated numerically within a two-dimensional approximation and compared with each other. The nozzle geometry is a 2D representation, extracted from the CAD model of the actual nozzles under experimental investigation. In the working conditions studied here, the nozzle is throttled differentially, by setting different flow conditions on the upper and lower inlet, with the aim of generating thrust vectoring effects. The performances and flowfield of both aerospikes are investigated for values of the nozzle pressure ratio (npr) ranging from 3.7 up to the design condition (NPR=200), and for several levels of differential throttling. The CFD approach adopted is based on a two-dimensional RANS flow model. Comparisons between the numerical and experimental data are performed at two nozzle working conditions: without and with differential throttling. The numerical results are in good agreement with the experimental data. Moreover, the numerical simulations of the throttling case have shown a thrust deflection of about 5 degrees, with a differential pressure of approximately 10 percent.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030200
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 201: Finite-Time Control for Satellite Formation
Reconfiguration and Maintenance in LEO: A Nonlinear Lyapunov-Based SDDRE
Approach
Authors: Majid Bakhtiari, Amirhossein Panahyazdan, Ehsan Abbasali
First page: 201
Abstract: This paper introduces a nonlinear Lyapunov-based Finite-Time State-Dependent Differential Riccati Equation (FT-SDDRE) control scheme, considering actuator saturation constraints and ensuring that the control system operates within safe operational limits designed for satellite reconfiguration and formation-keeping in low Earth orbit (LEO) missions. This control approach addresses the challenges of reaching the relative position and velocity vectors within a defined timeframe amid various orbital perturbations. The proposed approach guarantees precise formation control by utilizing a high-fidelity relative motion model that incorporates all zonal harmonics and atmospheric drag, which are the primary environmental disturbances in LEO. Additionally, the article presents an optimization methodology to determine the most efficient State-Dependent Coefficient (SDC) form regarding fuel consumption. This optimization process minimizes energy usage through a hybrid genetic algorithm and simulated annealing (HGASA), resulting in improved performance. In addition, this paper includes a sensitivity analysis to identify the optimized SDC parameterization for different satellite reconfiguration maneuvers. These maneuvers encompass radial, along-track, and cross-track adjustments, each with varying baseline distances. The analysis provides insights into how different parameterizations affect reconfiguration performance, ensuring precise and efficient control for each type of maneuver. The finite-time controller proposed here is benchmarked against other forms of SDRE controllers, showing reduced error margins. To further assess the control system’s effectiveness, an input saturation constraint is integrated, ensuring that the control system operates within safe operational limits, ultimately leading to the successful execution of the mission.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030201
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 202: Adapted Speed Control of Two-Stroke Engine
with Propeller for Small UAVs Based on Scavenging Measurement and Modeling
Authors: Yifang Feng, Tao Chen, Qinwang Liu, Heng Zhao
First page: 202
Abstract: The speed of the engine–propeller directly determines the power output for Unmanned Aerial Vehicles (UAV) with internal combustion engines. However, variable air pressure can impact the engine’s air exchange and combustion processes, causing minor changes that affect the engine speed and result in variations in propeller thrust. A single-loop control strategy was proposed incorporating a feed-forward air-intake model with throttle feedback for small UAVs equipped with a two-stroke scavenging internal combustion engine and propeller. The feed-forward model was built with a simplified model of the airpath based on the scavenging measurement, which combined the tracer gas method and CFD simulation by a two-zone combustion chamber model. The feed-forward control strategy was built by a simplified crankcase–scavenging–cylinder model with CFD results under different air pressures, demonstrating a 1% error compared with CFD simulation. An iterative method of feed-forwarding was suggested for computing efficiency. A feedback controller was constructed using fuzzy PID for minimal instrumentation in engine control for small aircraft. Finally, the single-loop control strategy was validated through simulation and experimentation. The results indicate an 89% reduction in average speed error under varying air pressure and an 83.7% decrease in average speed overshoot in continuous step speed target experiments.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030202
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 203: SAC-Based Intelligent Load Relief Attitude
Control Method for Launch Vehicles
Authors: Shou Zhou, Hao Yang, Shifeng Zhang, Xibin Bai, Feng Wang
First page: 203
Abstract: This paper proposes an intelligent control method based on Soft Actor-Critic (SAC) to address uncertainties faced by flight vehicles during flight. The method effectively reduces aerodynamic loads and enhances the reliability of structural strength under significant wind disturbances. A specific launch vehicle is taken as the research subject, and its dynamic model is established. A deep reinforcement learning (DRL) framework suitable for the attitude control problem is constructed, along with a corresponding training environment. A segmented reward function is designed: the initial stage emphasizes tracking accuracy, the middle stage, with a detrimental effect due to the high-altitude wind region, focuses on load relief, and the final stage gradually resumes following tracking accuracy on the basis of maintaining the effect of load relief. The reward function dynamically switches between stages using a time factor. The improved SAC algorithm is employed to train the agent over multiple epochs, ultimately resulting in an intelligent load relief attitude controller applicable to the launch vehicle. Simulation experiments demonstrate that this method effectively solves the attitude control problem under random wind disturbances, particularly reducing the aerodynamic loads of launch vehicles in the high-altitude wind region.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030203
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 204: A Hybrid EMD-ICA-DLinear Multi-View
Representation Model for Accurate Satellite Orbit Prediction in Space
Authors: Yang Guo, Boyang Wang, Zhengxu Zhao
First page: 204
Abstract: Accurate prediction of the on-orbit positions of Low Earth Orbit (LEO) satellites is essential for mission success, operational efficiency, and safety. Nevertheless, the non-stationary nature of orbital data and sensor noise presents significant challenges for accurate prediction. To address these challenges, we propose a novel forecasting model, EMD-ICA-DLinear, which combines trend-residual representation with EMD-ICA in an innovative manner. By integrating the TSR (Trend, Seasonality, and Residual) framework with the EMD-ICA dual perspective, this approach provides a comprehensive understanding of time series data and outperforms traditional models in capturing subtle nonlinear relationships. When predicting the orbital position of the Fengyun-3C satellite, the model uses MSE and MAE as evaluation metrics. Experimental results indicate that the proposed EMD-ICA-DLinear hybrid model achieves MSE and MAE values of 0.1101 and 0.1567, respectively, when predicting the orbital position of the Fengyun-3C satellite 6 h in advance, representing reductions of 37.87% and 19.85% compared to the best baseline model, TimesNet. This advancement enhances satellite orbit prediction accuracy, supports operational stability, and enables timely adjustments, thereby improving mission efficiency and safety.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030204
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 205: Experimental Study on the
Ignition/Extinction Performances of a Central Staged Direct Mixing
Combustor and the Construction of an Engineering Prediction Model
Authors: Wenhui Ling, Pengfei Zhu, Yan Zhang, Yuqing Wang, Yinhui Wang, Ni Jiang
First page: 205
Abstract: The ignition and extinction performances of an engine’s combustion chamber are crucial for its overall performance, reliability, fuel efficiency, and environmental impact. This study focuses on a central staged dual-swirl direct mixing combustor’s ignition and extinction performances. The goal is to construct a network surrogate prediction model estimating the ignition and extinction boundaries in the central staged dual-swirl direct mixing combustor. The experimental results indicate that the minimum ignition fuel–air ratio of the combustor initially increases and then decreases with increasing inlet temperature. In contrast, the extinction fuel–air ratio decreases with increasing inlet temperature. The ignition fuel–air ratio decreases as the inlet pressure increases, while the extinction fuel–air ratio also decreases with increasing inlet pressure. The minimum ignition fuel–air ratio initially decreases and then increases as the inlet flow rate increases. Similarly, the extinction fuel–air ratio decreases with increasing inlet flow rate. Additionally, both the ignition and extinction fuel–air ratios decrease with increasing pilot and main stage swirl intensity. The constructed neural network model comprises an output layer representing the ignition and extinction fuel–air ratios and an input layer including variables such as inlet temperature, pressure, flow rate, and pilot and main swirl intensity. During training, the model achieved a final relative error of 0.4%, with a relative error of 0.3% for the ignition fuel–air ratio and 0.5% for the extinction fuel–air ratio. During validation, the relative error was 1.7%, with a relative error of 1.1% for the ignition fuel–air ratio and 2.1% for the extinction fuel–air ratio. The neural network model demonstrates its effectiveness in accurately predicting the numerical values of the ignition and extinction fuel–air ratios, indicating its potential for engineering predictions in the context of central staged dual-swirl direct mixing combustors.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030205
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 206: Identifying Human Factor Causes of Remotely
Piloted Aircraft System Safety Occurrences in Australia
Authors: John Murray, Steven Richardson, Keith Joiner, Graham Wild
First page: 206
Abstract: Remotely piloted aircraft are a fast-emerging sector of the aviation industry. Although technical failures have been the largest cause of accident occurrences for Remotely Piloted Aircraft Systems (RPASs), if they are to follow the path of conventionally crewed aviation, Human Factors (HFs) will increasingly contribute to accidents as the technology of RPASs improves. Examining an RPAS accident database from 2008–2019 for HF-caused accidents and coding to the Human Factors Analysis and Classification System (HFACS) taxonomy, an exploration of RPAS HFs is carried out and the predominant HF issues for RPAS pilots identified. The majority of HF accidents were coded to the Unsafe Acts level of the HFCAS. Skill errors, depth perception and environmental issues were the largest contributors to HF RPAS safety occurrences. A comparison with other sectors of aviation is also made where perception issues were found to be a greater contributor to occurrences for RPAS pilots than for other sectors of aviation. Developing appropriate training programs to develop skilled RPAS operators with good depth perception can contribute to a reduction in RPAS accident rates. The importance of reporting RPAS incidents is also discussed.
Citation: Aerospace
PubDate: 2025-02-28
DOI: 10.3390/aerospace12030206
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 207: Research on the Dynamic Modeling of
Rigid–Flexible Composite Spacecraft Under Fixed Constraints Based on
the ANCF
Authors: Jiaqi Wu, Guohua Kang, Junfeng Wu, Chuanxiao Xu, Jiayi Zhou, Xinyong Tao, Yinmiao Hua
First page: 207
Abstract: Dynamically modeling the flexible characteristics of large-scale jointed composite spacecraft is challenging. In this study, a dynamic modeling method for rigid–flexible composite spacecraft is proposed based on the absolute nodal coordinate formulation (ANCF). First, the spacecraft in the jointed composite is simplified as a rigid body, and the docking mechanisms between spacecraft are approximated using the fully parameterized beam model. Next, regarding the constraints between the beam and the rigid body, the beam’s absolute nodal coordinates are converted into rigid body coordinates. This allows the dynamic equations to be simplified using independent coordinates, reducing the model dimension. Finally, system damping is increased through the mean stress noise reduction method, which suppresses high-frequency components in the dynamic model and further reduces the rigidity of the dynamic equations for the composite body. This modeling method decreases the complexity of the composite body dynamics and avoids the difficulty of solving algebraic–differential equations exhibited by Lagrange multiplier methods, facilitating numerical simulations. The proposed method is applicable to both tree and mesh topologies. MATLAB simulations demonstrate that the proposed dynamic model alleviates the dimensionality disaster caused by conventional algorithms, significantly reducing computation time. The simulation results are consistent with ADAMS. The proposed model exhibits displacement errors less than 1 mm, highlighting its efficiency and accuracy.
Citation: Aerospace
PubDate: 2025-03-01
DOI: 10.3390/aerospace12030207
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 208: Study on Ignition Characteristics of
Microblog Radiation Ignitor
Authors: Hao Zeng, Changqin Fu, Zhiyu Zhao
First page: 208
Abstract: This study explored methods used to improve the ignition efficiency of a microwave radiation igniter; experimental analyses were conducted to characterize the device’s performance in a model combustion chamber. High-speed imaging combined with an image intensifier tracked flame kernel formation and propagation dynamics under varying airflow rates, residual gas coefficients, and microwave pulse parameters. The results demonstrate that increased airflow rates reduced the relative decline in ignition delay time under microwave application, with the flame area growth curve exhibiting a steeper slope compared to non-microwave conditions. Elevated residual gas coefficients enhanced the microwave-induced reduction in ignition delay time, though this effect weakened significantly in fuel-rich environments. Additionally, higher microwave pulse frequencies and peak power levels both contributed to shorter ignition delay times; the delay decreased linearly with the rising pulse frequency and followed a power-dependent reduction trend. These findings systematically quantify the synergistic effects of flow dynamics, residual gases, and microwave parameters on ignition performance.
Citation: Aerospace
PubDate: 2025-03-04
DOI: 10.3390/aerospace12030208
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 209: The Impact of Gust Load Design Criteria on
Vehicle Structural Weight for a Persistent Surveillance Platform
Authors: Jerry Wall, Zack Krawczyk, Ryan Paul
First page: 209
Abstract: This paper introduces a methodology for structural mass optimization of High-Altitude Long Endurance (HALE) aircraft across a complete mission profile, tailored for use in preliminary design. A conceptual HALE vehicle and its mission profile are assumed for this study, which also evaluates the impact of risk-based design decisions on optimized mass. The research incorporates a coupled aeroelastic solver and a mass optimization algorithm based on classical laminate theory to construct a geometrically accurate spar model. A novel approach is proposed to minimize the spar mass of the aircraft throughout the mission profile. This algorithm is applied to a representative T-Tail HALE model to compare optimized mass between two mission profiles differing in turbulence exceedance levels during the ascent and descent mission stages, while maintaining the same design robustness for on-station operation. Sample numerical results reveal a 10.9% reduction in structural mass for the mission profile with lower turbulence robustness design criteria applied for ascent and descent mission phases. The significant mass savings revealed in the optimization framework allow for a trade-off analysis between robustness to turbulence impacts and critical HALE platform parameters such as empty weight. The reduced empty vehicle weight, while beneficial to vehicle performance metrics, may be realized but comes with the added safety of flight risk unless turbulent conditions can be avoided during ascent and descent through risk mitigation strategies employed by operators. The optimization framework developed can be incorporated into system engineering tools that evaluate mission effectiveness, vehicle performance, vehicle risk of loss, and system availability over a desired operating area subject to environmental conditions.
Citation: Aerospace
PubDate: 2025-03-05
DOI: 10.3390/aerospace12030209
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 210: Thrust Measurement of an Integrated
Multi-Sensor Micro-Newton Cold Gas Thruster
Authors: Songcai Lu, Yong Gao, Haibo Tu, Xudong Wang, Xinju Fu, Gang Meng, Jun Long, Xuhui Liu, Yong Li
First page: 210
Abstract: In recent years, cold gas thrusters have been successfully deployed in numerous missions, showcasing their exceptional reliability and enabling ultra-precise space operations across a broad thrust range. This article introduces an integrated cold gas thruster that integrates flow, pressure, and displacement sensors. The thrust range of this thruster can exceed 1000 μN at most, and the resolution can reach up to 0.1 μN at low thrust. The results of the high-precision displacement sensor are good, showing that the thruster performs well in terms of flow control accuracy and thrust output sensitivity. The measurement accuracy of the force frame itself is also excellent, and it can detect small thrust changes of 0.1 μN. The thrust noise level of the thruster is good, comparable to the standard noise levels of the experimental environment.
Citation: Aerospace
PubDate: 2025-03-06
DOI: 10.3390/aerospace12030210
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 211: Exploration of Earth’s Magnetosphere
Using CubeSats with Electric Propulsion
Authors: Alessandro A. Quarta
First page: 211
Abstract: The study of the Earth’s magnetosphere through in situ observations is an important step in understanding the evolution of the Sun–Earth interaction. In this context, the long-term observation of the Earth’s magnetotail using a scientific probe in a high elliptical orbit is a challenging mission scenario due to the alignment of the magnetotail direction with the Sun–Earth line, which requires a continuous rotation of the apse line of the spacecraft’s geocentric orbit. This aspect makes the mission scenario particularly suitable for space vehicles equipped with propellantless propulsion systems, such as the classic solar sails which convert the solar radiation pressure into propulsive acceleration without propellant expenditure. However, a continuous rotation of the apse line of the osculating orbit can be achieved using a more conventional solar electric thruster, which introduces an additional constraint on the duration of the scientific mission due to the finite mass of the propellant stored on board the spacecraft. This paper analyzes the potential of a typical CubeSat equipped with a commercial miniaturized electric thruster in performing the rotation of the apse line of a geocentric orbit suitable for the in situ observation of the Earth’s magnetotail. The paper also analyzes the impact of the size of a thruster array on the flight performance for an assigned value of the payload mass and the science orbit’s characteristics. In particular, this work illustrates the optimal guidance laws that allow us to maximize the duration of the scientific mission for an assigned CubeSat’s configuration. In this sense, this paper expands the literature regarding the study of this interesting mission scenario by extending the study to conventional propulsion systems that use a propellant to provide a continuous and steerable thrust vector.
Citation: Aerospace
PubDate: 2025-03-06
DOI: 10.3390/aerospace12030211
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 212: Dynamics Simulation and Optimization of
Gliding Tail Decoy
Authors: Huayu Jia, Huilong Zheng, Shunbo Huo, Hong Zhou
First page: 212
Abstract: In this paper, a gliding tail decoy for a UAV is proposed, which can be discarded as a decoy when the UAV encounters danger. Based on an aerodynamic model of the tail decoy, a nonlinear dynamics model of the tail decoy gliding in the air is generated, and a three-layer pyramid general design architecture of the tail decoy is established. In order to subsequently analyze the dynamic characteristics and gliding trajectory of the gliding tail decoy, a gliding trajectory simulation software is developed based on the dynamics model of the gliding tail. Selecting the pre-optimized tail shape as the research object, and analyzing the influence of deployment speed and deployment posture angle on the tail trajectory, it was found that a deployment speed of 60 m/s and a deployment posture angle of 8° are more conducive to the tail obtaining a larger gliding distance. In addition, the effectiveness of the optimization method for the gliding tail in this article was verified. It was found that after optimizing the shape of the gliding tail, the lift coefficient increased in the range of 0°~14°, and the gliding distance increased by 4.2%.
Citation: Aerospace
PubDate: 2025-03-06
DOI: 10.3390/aerospace12030212
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 213: Koopman Predictor-Based Integrated Guidance
and Control Under Multi-Force Compound Control System
Authors: Qian Peng, Gang Chen, Jianguo Guo, Zongyi Guo
First page: 213
Abstract: This paper proposes a Koopman-predictor-based integrated guidance and control (IGC) law for the hypersonic target interceptor under the multi-force compound control. The strongly coupled and nonlinear guidance and control systems including the characteristics of the aerodynamic rudder, attitude control engine and orbit control engine are described as a linear IGC model based on the Koopman predictor. The proposed IGC law adapted to the linear IGC model is presented by combining the sliding mode control (SMC), the extended disturbance observer (EDO), and the adaptive weight-based control allocation scheme for being robust against the uncertainties and optimizing the fuel allocation for the fuel limited interceptor while intercepting the targets precisely. The stability of the proposed control law-based closed-loop system is guaranteed. The effectiveness and robustness of the proposed control law are proved by simulation comparisons and Monte Carlo tests.
Citation: Aerospace
PubDate: 2025-03-06
DOI: 10.3390/aerospace12030213
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 214: Simulation of Shock-to-Detonation
Transition by OpenFOAM
Authors: Thien Xuan Dinh, Masatake Yoshida, Shuichi Ishikura
First page: 214
Abstract: Shock-to-detonation transition (SDT) is the detonation of explosive charge triggered by the shock pressure from a nearby detonated explosive or an impact at high speed. A good prediction of SDT is a key in the design of explosives’ use, storage, and transportation. Typically, SDT simulation must use designated commercial software; therefore, a high license cost is necessary. This paper presents a simulation of SDT by a cost-effective hydrodynamic code developed on an open-source code framework, OpenFOAM. The code adopted the multi-material Eulerian method, Ignition and Growth reaction rate model, and Riemann solver to solve the shock-induced detonation phenomenon. The code was verified by a Pop plot calculation and a sympathetic detonation simulation. In the Pop plot calculation, the distance-of-run to the detonation of Composition B depending on the initial shock pressure was simulated. The reactant and product phases of Composition B were modeled by the Jone–Wilkins–Lee (JWL) equation of state (EOS). The aluminum plate used to create the initial shock pressure was modeled by shock Mie–Gruneisen (MG) EOS. The predicted distance-of-run against the initial shock pressure was in good agreement with an empirical correlation and experimental data. In the sympathetic detonation simulation, the charge explosive and nearby explosive were Composition B and were modeled by JWL EOS as in the Pop plot calculation and the plexiglass gap was modeled by MG EOS. The simulated critical gap for the sympathetic detonation was well predicted as in the other published data. This implies that the code is valid for SDT simulation. In addition, it is a cost-effective simulation, since the code was developed on open-source code, so massive computation can then be run without license costs.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030214
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 215: Advances in Composite Materials for Space
Applications: A Comprehensive Literature Review
Authors: Konstantinos Tserpes, Ioannis Sioutis
First page: 215
Abstract: Space structures are perhaps the most complicated man-made structures due to their extremely harsh and complex operational environments. For these structures, materials serve as crucial technology drivers. Composite materials are increasingly used in space structures due to their specific mechanical properties, customizability, and ability to easily acquire multifunctional and smart characteristics. This review critically examines the state of the art in composite materials application and the computational models used to design and analyze composite space structures.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030215
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 216: The Design and Evaluation of a Direction
Sensor System Using Color Marker Patterns Onboard Small Fixed-Wing UAVs in
a Wireless Relay System
Authors: Kanya Hirai, Masazumi Ueba
First page: 216
Abstract: Among the several usages of unmanned aerial vehicles (UAVs), a wireless relay system is one of the most promising applications. Specifically, a small fixed-wing UAV is suitable to establish the system promptly. In the system, an antenna pointing control system directs an onboard antenna to a ground station in order to form and maintain a communication link between the UAV and the ground station. In this paper, we propose a sensor system to detect the direction of the ground station from the UAV by using color marker patterns for the antenna pointing control system. The sensor detects the difference between the antenna pointing direction and the ground station direction. The sensor is characterized by the usage of both the color information of multiple color markers and color marker pattern matching. These enable the detection of distant, low-resolution markers, a high accuracy of marker detection, and robust marker detection against motion blur. In this paper, we describe the detailed algorithm of the sensor, and its performance is evaluated by using the prototype sensor system. Experimental performance evaluation results showed that the proposed method had a minimum detectable drawing size of 10.2 pixels, a motion blur tolerance of 0.0175, and a detection accuracy error of less than 0.12 deg. This performance indicates that the method has a minimum detectable draw size that is half that of the ArUco marker (a common AR marker), is 15.9 times more tolerant of motion blur than the ArUco marker, and has a detection accuracy error twice that of the ArUco marker. The color markers in the proposed method can be placed farther away or be smaller in size than ArUco markers, and they can be detected by the onboard camera even if the aircraft’s attitude changes significantly. The proposed method using color marker patterns has the potential to improve the operational flexibility of radio relay systems utilizing UAVs and is expected to be further developed in the future.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030216
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 217: Exploring the Design Space of Low-Thrust
Transfers with Ballistic Terminal Coast Segments in Cis-Lunar Space
Authors: Kevin I. Alvarado, Sandeep K. Singh
First page: 217
Abstract: Spacecraft catering to the Lunar Gateway or other “permanent” stations in the lunar vicinity would require frequent travel between periodic orbits around the Earth–Moon L1 and L2 Lagrange points. The transition through the Hill sphere is often characterized by close passages of our nearest neighbor—rendering the optimization problem numerically challenging due to the increased local sensitivities. Depending on the mission requirements and resource constraints, transfer architectures must be studied, and trade-offs between flight time and fuel consumption quantified. While direct low-thrust transfers between the circular restricted three-body problem periodic orbit families have been studied, the asymptotic flow in the neighborhood of the periodic orbits could be leveraged for expansion and densification of the solution space. This paper presents an approach to achieve a dense mapping of manifold-assisted, low-thrust transfers based on initial and terminal coast segments. Continuation schemes are utilized to attain the powered intermediate time-optimal segment through a multi-shooting approach. Interesting insights regarding the linear correlation between ΔV and change in reduced two-body osculating elements associated with the initial-terminal conditions are discussed. These insights could inform the subsequent filtering of the osculating selenocentric periapsis map and provide additional interesting and efficient solutions. The described approach is anticipated to be extremely useful for future crewed and robotic cis-lunar operations.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030217
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 218: A Deployable Conical Log Spiral Antenna for
Small Spacecraft: Electronic Design and Test
Authors: Lewis R. Williams, Karina Vieira Hoel, Lars Erling Bråten, Arthur Romeijer, Natanael Hjermann, Bendik Sagsveen
First page: 218
Abstract: An ultra-high-frequency (UHF) deployable conical log spiral antenna’s design and experimental test results are presented. The antenna is a spring constructed from a carbon-fiber-infused epoxy matrix. The spring design simplified the spacecraft deployment mechanism, and the use of composite materials allowed for the integration of radiating elements into the spring structure. A Chebyshev transformer at the base of the antenna is used to match the incoming transmission line impedance to a 95 Ω coaxial cable. The 95 Ω coaxial, which is the balun and the radiating element, is embedded into the antenna structure. The antenna is fed at the cone’s base without requiring a ground plane whilst maintaining radiation in the cone’s apex-pointing direction. This facilitated an uncomplicated deployment mechanism. Prototypes have been manufactured for 500 to 1500 MHz designs. Antenna measurements show a realized gain of between approximately 3 to 6 dBi from 500 to 1500 MHz.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030218
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 219: Model-Free Adaptive Control for Attitude
Stabilization of Earth-Pointing Spacecraft Using Magnetorquers
Authors: Fabio Celani, Mohsen Heydari, Alireza Basohbat Novinzadeh
First page: 219
Abstract: This paper presents an attitude stabilization algorithm for a Low Earth Orbit (LEO) Earth-pointing spacecraft using magnetorquers as the only torque actuators and employing Model-Free Adaptive Control (MFAC) as the control algorithm. MFAC is a data-driven control algorithm that relies solely on input–output data from the plant. This paper validates the effectiveness of the proposed approach through numerical simulations in a specific case study. The simulations show that the proposed algorithm drives the spacecraft’s attitude to three-axis stabilization in the orbital frame from arbitrary initial tumbling conditions. The numerical study also shows that the proposed control algorithm outperforms a model-based Proportional–Derivative (PD) control in terms of pointing accuracy at the expense of higher energy consumption.
Citation: Aerospace
PubDate: 2025-03-07
DOI: 10.3390/aerospace12030219
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 220: Reassessing the ICAO’s Standard
Taxi/Ground Idle Time: A Statistical Analysis of Taxi Times at 71 U.S. Hub
Airports
Authors: Jiansen Wang, Shantanu Gupta, Mary E. Johnson
First page: 220
Abstract: Taxi time plays a critical role in airport capacity, aircraft fuel consumption, and emissions. It is defined as the time from touchdown to the gate and from the gate to liftoff. The International Civil Aviation Organization (ICAO) established a standard taxi/ground idle time-in-mode (TIM) of 26 min in the landing and take-off (LTO) cycle for modeling turbine engine aircraft emissions. However, actual taxi times vary significantly across airports. While a simplified standard streamlines emissions modeling, the 26 min assumption may not accurately reflect real-world conditions. While using airport-specific taxi times may not always be practical, hub classifications of U.S. commercial airports may affect taxi time and serve as a compromise between airport-specific taxi times and a simplified standard. Therefore, this study statistically analyzed Federal Aviation Administration (FAA) data from 71 U.S. commercial hub airports to compare reported taxi times with the ICAO’s standard and assess the influence of airport hub classifications. The exploratory findings indicate that the 26 min ICAO taxi/idle TIM does not represent reported taxi times at 70 of the 71 sampled airports. Moreover, total taxi time varied by hub classification: small-hub airports had a mean taxi time of 19.82 min (median: 18 min), medium-hub airports had a mean taxi time of 19.72 min (median: 18.25 min), and large hubs had a mean taxi time of 26.98 min (median: 25.08 min). When hub classifications were ignored, the overall mean taxi time was 23.78 min (median: 22 min), indicating a statistically significant difference between the ICAO’s standard 26 min assumption and the observed taxi times at most airports.
Citation: Aerospace
PubDate: 2025-03-08
DOI: 10.3390/aerospace12030220
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 221: Effect of Dynamic Flexural Strength on
Impact Response Analysis of AlN Substrates for Aerospace Applications
Authors: Zhen Wang, Yan Liu
First page: 221
Abstract: Electronic devices play an extremely important role in the aerospace field. Aluminum nitride (AlN) is a promising ceramic material for high-reliability electronic packaging structures that are subjected to impact loads during service. Quasi-static and dynamic flexural tests were conducted to determine the rate-dependent flexural strengths of AlN ceramics. The impact response of the AlN substrates was investigated using experimental tests and a smeared fixed-crack numerical model. The critical velocity of the impactor and the failure mode of the ceramic plate can be accurately predicted using the Drucker–Prager criterion with the scaled fracture-strength parameter. The radial cracks on the ceramic plate upon impact were well reproduced via the proposed novel numerical technique, showing better accuracy compared to the widely used Johnson–Holmquist II (JH-2) model. The effect of impactor nose shape and deflection angles were further investigated to better illustrate the low-velocity impact response of AlN ceramic substrates. Based on the dynamic flexural-strength testing results, this study achieves the prediction of low-speed impact response for AlN ceramic structures, thereby providing technical support for the impact reliability analysis of aerospace ceramic-packaging devices.
Citation: Aerospace
PubDate: 2025-03-08
DOI: 10.3390/aerospace12030221
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 222: Flow Structures in a Compressible
Elliptical Cavity Flow
Authors: Yi-Xuan Huang, Kao-Chun Su, Kung-Ming Chung
First page: 222
Abstract: This experimental and numerical study determines the time-averaged flow patterns within an elliptical cavity at a freestream Mach number of 0.83. The elliptical cavity model has a length-to-depth ratio of 4.43, which is classified as an open cavity flow. The flow within the elliptical cavity exhibits distinctive features due to its unique geometry. A large clockwise-rotating recirculation vortex is created, which is a common feature of an open cavity flow. Tornado-like vortices are observed at positions farther from the centerline than those in a rectangular cavity because of the geometric effect of the diverging sidewalls in the front half of an elliptical cavity, which increases the spanwise motion by directing internal flow from the centerline towards the sidewalls. Additional vortex structures, such as a front corner vortex, a rear corner vortex and secondary tornado-like vortices near the sidewalls, are identified. These structures contribute to complex flow interactions, including vortex–vortex, vortex–wall, and shear layer interactions. The three-dimensional effect affects the cellular structures within the cavity, which is similar to the effect for a rectangular cavity with a large length-to-width ratio.
Citation: Aerospace
PubDate: 2025-03-09
DOI: 10.3390/aerospace12030222
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 223: Explainable Supervised Learning Models for
Aviation Predictions in Australia
Authors: Aziida Nanyonga, Hassan Wasswa, Keith Joiner, Ugur Turhan, Graham Wild
First page: 223
Abstract: Artificial intelligence (AI) has demonstrated success across various industries; however, its adoption in aviation remains limited due to concerns regarding the interpretability of AI models, which often function as black box systems with opaque decision-making processes. Given the safety-critical nature of aviation, the lack of transparency in AI-generated predictions poses significant challenges for industry stakeholders. This study investigates the classification performance of multiple supervised machine learning models and employs SHapley Additive exPlanations (SHAPs) to provide global model explanations, identifying key features that influence decision boundaries. To address the issue of class imbalance in the Australian Transport Safety Bureau (ATSB) dataset, a Variational Autoencoder (VAE) is also employed for data augmentation. A comparative evaluation of four machine learning algorithms is conducted for a three-class classification task:—Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF), and a deep neural network (DNN) comprising five hidden layers. The results demonstrate a competitive performance across accuracy, precision, recall, and F1-score metrics, highlighting the effectiveness of explainable AI techniques in enhancing model transparency and fostering trust in AI-driven aviation safety applications.
Citation: Aerospace
PubDate: 2025-03-09
DOI: 10.3390/aerospace12030223
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 224: The Assembly, Integration and Test of the
DORA Telescope, a Deployable Optics System in Space for Remote Sensing
Applications
Authors: Igor Di Varano, Fabrizio Capaccioni, Giovanna Rinaldi, Gianrico Filacchione, David Biondi, Giancarlo Bellucci, Alfredo Morbidini, Bortolino Saggin
First page: 224
Abstract: The paper deals with the assembling, integration, and test (AIT) phase of the laboratory model of an innovative telescope in the framework of the project DORA (deployable optics for remote sensing applications). The telescope is a Cassegrain type of instrument, with an entrance pupil of ∅300 mm, f/16 aperture, and FOV of 0.16°. It has been designed to be mounted onboard a micro-satellite frame, allowing for switching between a stowed configuration during the launch phase and a deployed one once in orbit. The telescope is matched to an infrared Fourier spectrometer, operating in the spectral range of 5–25 μm, for the observation of terrestrial atmospheric phenomena, but it can also be adopted for planetary exploration missions. The telescope breadboard has been assembled in the INAF-IAPS premises and has undergone measurements for the determination of the accuracy and repeatability of the mechanism opening. The mechanical tests have demonstrated that the deployment mechanism adopted complies with the requirements imposed by the infrared Fourier spectrometer, guaranteeing a repositioning of the secondary mirror with respect to the primary mirror within 100 μm (in-plane displacement) and 0.01° (tilt) of the nominal position.
Citation: Aerospace
PubDate: 2025-03-10
DOI: 10.3390/aerospace12030224
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 225: Aerodynamic Characteristics and Dynamic
Stability of Coning Motion of Spinning Finned Projectile in Supersonic
Conditions
Authors: Jintao Yin, Shengju Jiang, Yaowei Hu, Jiawei Zhang, Haochun Miao, Juanmian Lei
First page: 225
Abstract: For a spinning projectile, coning motion induced by disturbances during flight can have a unique impact on the lateral force and yawing moment, which may further affect flight stability and maneuverability. The flow over a coupled spinning–coning projectile and a spinning projectile was numerically simulated by solving the unsteady Reynolds-averaged Navier–Stokes (URANS) equation with an implicit dual-time stepping method and a spinning–coning coupled motion model established through a dynamic mesh technique. The variation in transient and time-averaged aerodynamic characteristics with the angle of attack (AoA), dimensionless spin rate, and dimensionless cone rate was analyzed, and the specific effect of coning motion on the lateral force and yawing moment was revealed. Based on these findings, the yawing moment term in traditional angular motion theory was modified, and the flight response to the initial disturbance was discussed. The results indicate that the time-averaged lateral force and yawing moment of the spinning–coning coupled projectile are multiplied compared with those of the spinning projectile and vary linearly with the dimensionless spin rate and cone rate. The main factors affecting the lateral force are the coning motion-induced effective angle of sideslip (AoS), asymmetric expansion waves, and asymmetric vortices. The much larger yawing moment induced by spinning–coning coupled motion can more easily cause AoA divergence and flight instability.
Citation: Aerospace
PubDate: 2025-03-10
DOI: 10.3390/aerospace12030225
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 226: Numerical Investigation of the Two-Phase
Flow Characteristics of an Axisymmetric Bypass Dual-Throat Nozzle
Authors: Xuefeng Xia, Zhensheng Sun, Yu Hu, Hongfu Qiang, Yujie Zhu, Yin Zhang
First page: 226
Abstract: The bypass dual-throat nozzle is based on the dual-throat nozzle, which is a fluidic thrust vector nozzle suitable for integration into rocket motors in a symmetrical manner. As the effects of gas–solid two-phase flows are essential for solid rocket motors (SRMs), this study employs the RNG k–ε turbulence model and a particle trajectory model to numerically simulate the three-dimensional flow field inside a fixed-geometry axisymmetric bypass dual-throat nozzle to investigate its two-phase flow characteristics and thrust vectoring performance. Numerical results reveal that the smaller-diameter particles exhibit better flow-following characteristics and have a more significant impact on nozzle performance. As particle size increases, particle trajectories gradually rise within the cavity and converge toward the nozzle axis until a critical value is exceeded, after which the distribution tends to disperse. Particle deposition occurs at the bends of the bypass channel, the upstream converging section of the nozzle, and the converging section of the cavity, underscoring the need for a reinforced geometric design and thermal protection. In addition, the introduction of the particle phase into the flow reduces the thrust-vectoring angle of the nozzle and results in a loss of thrust coefficient. This research has the potential to guide the design of engines according to the incorporation of metal powder in propellants and combustion control.
Citation: Aerospace
PubDate: 2025-03-11
DOI: 10.3390/aerospace12030226
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 227: Airspace Structure Study with Capacity
Compensation for Increasing Diverse Operations
Authors: Tobias Welsch, Marco-Michael Temme
First page: 227
Abstract: Future aircraft designs with a wide range of performance parameters, such as electric and supersonic aircraft, will have to be accommodated in traditional airspace designs in the future. Allowing an individual optimization of traditional approach speed profiles has a similar, broadening effect on approach speed characteristics. The resulting necessity of integrating Increasing Diverse Operations (IDO) will lead to a reduction in capacity at hub airports, as larger gaps will have to be inserted between aircraft with very different speed profiles. This is due to the large range of different approach speeds that IDO encompasses. Such a development will present a challenge for airports, which are already operating at or near their capacity limit. An alternative routing towards an intercept point at a late stage of the final approach can provide two approach options with low interference for subsequent traffic. Based on traffic data from London Heathrow, this study evaluates the performance in terms of runway capacity for different constellations of this procedure. Moreover, the biphasic evaluation, conducted through theoretical calculations for a constant separation distance and a fast-time simulation for a constant separation time, yielded key findings that facilitated the development of an optimized procedure for a traffic mix with significant speed differences to compensate IDO-related capacity losses as far as possible.
Citation: Aerospace
PubDate: 2025-03-11
DOI: 10.3390/aerospace12030227
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 228: Robust MPS-INS UKF Integration and
SIR-Based Hyperparameter Estimation in a 3D Flight Environment
Authors: Juyoung Seo, Dongha Kwon, Byungjin Lee, Sangkyung Sung
First page: 228
Abstract: This study introduces a pose estimation algorithm integrating an Inertial Navigation System (INS) with an Alternating Current (AC) magnetic field-based navigation system, referred to as the Magnetic Positioning System (MPS), evaluated using a 6 Degrees of Freedom (DoF) drone. The study addresses significant challenges such as the magnetic vector distortions and model uncertainties caused by motor noise, which degrade attitude estimation and limit the effectiveness of traditional Extended Kalman Filter (EKF)-based fusion methods. To mitigate these issues, a Tightly Coupled Unscented Kalman Filter (TC UKF) was developed to enhance robustness and navigation accuracy in dynamic environments. The proposed Unscented Kalman Filter (UKF) demonstrated a superior attitude estimation performance within a 6 m coil spacing area, outperforming both the MPS 3D LS (Least Squares) and EKF-based approaches. Furthermore, hyperparameters such as alpha, beta, and kappa were optimized using the Sequential Importance Resampling (SIR) process of the Particle Filter. This adaptive hyperparameter adjustment achieved improved navigation results compared to the default UKF settings, particularly in environments with high model uncertainty.
Citation: Aerospace
PubDate: 2025-03-11
DOI: 10.3390/aerospace12030228
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 229: Designing an Urban Air Mobility Corridor
Network: A Multi-Objective Optimization Approach Using U-NSGA-III
Authors: Zhiyuan Zhang, Yuan Zheng, Chenglong Li, Bo Jiang, Yichao Li
First page: 229
Abstract: The corridor network serves as an effective solution for the airspace structure safety design of UAM. However, current studies rarely account for the ground risk posed by the corridor operation and typically consider a single design objective with limited variables. In this paper, we address these gaps by considering three key factors: demand, safety, and implementation costs. The corridor network design is formulated as a multi-objective optimization problem. In practice, firstly, we define the travel time-saving rate, average population density, and total length of corridors as optimization objectives. Then, we propose a straightforward and efficient corridor network encoding scheme that supports a variable number of corridors, significantly enhancing the diversity and flexibility of corridor network designs. Finally, based on this encoding scheme, we solve the corridor network problem using the unified non-dominated sorting genetic algorithm III (U-NSGA-III). Based on a detailed analysis of the obtained Pareto front, a relatively optimal design scheme across three optimization objectives is determined. The case study conducted in Chengdu illustrates that the corridor network obtained by our method not only achieves a 37.8% reduction in ground risk and a 69.9% decrease in implementation costs, but also saves a comparable 4.7% in time relative to traditional methods.
Citation: Aerospace
PubDate: 2025-03-12
DOI: 10.3390/aerospace12030229
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 230: Efficient Methodology for Power Management
Optimization of Hybrid-Electric Aircraft
Authors: Giuseppe Palaia, Karim Abu Salem, Erasmo Carrera
First page: 230
Abstract: This paper presents an effective simplified model to optimize the mission power management supply for hybrid-electric aircraft in the conceptual design phase. The main aim is to show that, by using simplified representations of the aircraft dynamics, it is possible to achieve reliable results and identify trends useful for early-stage design, avoiding the use of more expensive and advanced methods. This model has been integrated into a multidisciplinary design framework, where the mission analysis, based on a simplified point mass dynamic model, focuses on splitting the power supply between electric and thermal power throughout the flight. An optimization algorithm identifies the time profiles of the supplied power, thermal and electric, to minimize fuel consumption. The power supplied by the thermal engine, modeled as a time piecewise function, is a design variable; a parametric study on the number of intervals composing this function is performed. The framework is used to propose a generalized approach for hybrid-electric power management optimization during the conceptual design iterations. This study showed that, for regional hybrid-electric aircraft, dividing the airborne mission into climb, cruise and descent is sufficient to define the optimum power split supply profiles. This allows for the avoiding of finer mission discretization, or the adoption of more complex simulative models, providing a very efficient model.
Citation: Aerospace
PubDate: 2025-03-12
DOI: 10.3390/aerospace12030230
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 231: Performance and Emissions Evaluation of a
Turbofan Burner with Hydrogen Fuel
Authors: Maria Cristina Cameretti, Roberta De Robbio, Vincenzo Ferrara, Raffaele Tuccillo
First page: 231
Abstract: This paper examines the changes in the performance level and pollutant emissions of a combustion chamber for turbofan engines. Two different fuels are compared: a conventional liquid fuel of the JET-A (kerosene) class and a hydrogen-based gaseous fuel. A turbofan engine delivering a 70 kN thrust at cruise conditions and 375 kN thrust at take-off is considered. The comparison is carried out by investigating the combustion pattern with different boundary conditions, the latter assigned along a typical flight mission. The calculations rely on a combined approach with a preliminary lumped parameter estimation of the engine performance and thermodynamic properties under different flight conditions (i.e., take-off, climbing, and cruise), and a CFD-based combustion simulation employing as boundary conditions the outputs obtained from the 0-D computations. The results are discussed in terms of performance, thermal properties, distributions throughout the combustor, and of pollutant concentration at the combustor outflow. The results demonstrate that replacing the JET-A fuel with hydrogen does not affect the overall engine performance significantly, and stable and efficient combustion takes place inside the burner, although a different temperature regime is observable causing a relevant increase in thermal NO emissions.
Citation: Aerospace
PubDate: 2025-03-12
DOI: 10.3390/aerospace12030231
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 232: Design of High-Efficiency Jet Lift
Enhancement for Flaps Under Propeller Slipstream Influence
Authors: Yan Shao, Wanbo Wang, Jiao Sun, Wenyi Chen, Xinhai Zhao, Jiaxin Pan
First page: 232
Abstract: Both propeller slipstream and flap jet flow can significantly increase the aircraft lift coefficient. To establish design principles for efficient lift enhancement via jet flow under the influence of slipstream, wind tunnel experiments are conducted on a wing with propeller slipstream and jet flow. Force measurements using a balance and flow field measurements using hot-wire anemometry are employed to investigate the effects of different jet flow distribution methods on lift enhancement. The results indicate that the coupling of slipstream and jet flow effects can significantly increase wing lift. The stronger the slipstream effect, the more pronounced the lift enhancement under the same momentum coefficient. At the same thrust coefficient, a higher momentum coefficient is required in the slipstream-affected region to suppress airflow separation. Under the same jet flow rate, increasing the momentum coefficient in the slipstream-affected region can significantly improve lift enhancement. At the thrust coefficient of 0.46 and the momentum coefficient of 0.1, the optimized jet flow distribution method achieved a 52.6% greater lift enhancement compared to the spanwise uniform jet flow distribution method.
Citation: Aerospace
PubDate: 2025-03-13
DOI: 10.3390/aerospace12030232
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 233: Fast Reroute Mechanism for Satellite
Networks Based on Segment Routing and Dual Timers Switching
Authors: Jinyan Du, Ran Zhang, Jiangbo Hu, Tian Xia, Jiang Liu
First page: 233
Abstract: Low-Earth-Orbit (LEO) satellite networks have the advantage of global internet coverage and low latency, and they have enjoyed great success in the past few years. In LEO satellite networks, laser-based inter-satellite links (ISLs) are widely employed to achieve on-board data relay, and further to provide high-capacity backhaul worldwide. However, ISLs are prone to break due to the outage of the ISL capturing, tracking, and aiming systems. Meanwhile, breaks caused by different reasons can last from milliseconds to hours. The hybrid ISL fault leads to the on-board routing protocol to flap frequently, thus causing high routing overheads, low convergence speed, and degraded service consistency. In this work, we propose a hybrid fault detection mechanism to identify transient and long-term ISL outage. Further, for transient link outage, the segment routing-based loop-free backup path is adopted to provide real-time transmission recovery, and precise global route convergence is adopted to restore the long-term routing failure. For the inconsistent routing table switch between the phase from transient to long-term fault, we propose a dual timer mechanism to make sure the path can be smoothly switched without micro-loops. Simulation results validate the feasibility and efficiency of the proposed scheme.
Citation: Aerospace
PubDate: 2025-03-13
DOI: 10.3390/aerospace12030233
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 234: Modelling of the Power Demand of Peripheral
Aggregates of an Airborne Fuel Cell-Based Power System
Authors: Nejat Mahdavi
First page: 234
Abstract: Because of the higher energy density of hydrogen as a clean energy source, the use of proton exchange membrane fuel cells (PEMFCs) for aviation applications has become an important research topic in recent years. Unlike batteries, fuel cells require a lot of peripheral aggregates to operate properly. The peripheral aggregates of a fuel cell, which constitute the so-called balance of plant (BoP), consume a certain part of the power generated by the fuel cell stack, which reduces the overall efficiency of the fuel cell system. One of the greatest challenges in the design of a fuel cell system is the sizing of the fuel cell stack and the determination of the internal power consumption of the BoP. This paper models the power demand of the BoP of a fuel cell system based on an automotive fuel cell power system. Furthermore, the effect of flight altitude on the power demand of the BoP is investigated.
Citation: Aerospace
PubDate: 2025-03-13
DOI: 10.3390/aerospace12030234
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 235: Mechanical and Thermal Contributions to the
Damage Suffered by an Aeronautical Structure Subjected to an Intense and
Sudden Electrical Discharge
Authors: Bryan Better, Aboulghit El Malki Alaoui, Christine Espinosa, Michel Arrigoni, Nathan Menetrier, Chabouh Yazidjian, Serge Guetta, Frédéric Lachaud, Christian Jochum, Michel Boustie, Didier Zagouri
First page: 235
Abstract: Lightweight aeronautical structures and power generation structures such as wind turbines are fitted with protected external layers designed and certified to withstand severe climatic events such as lightning strikes. During these events, high currents flow through the structural protection but are likely to induce effects deeper in the supporting composite material and could even reach or perforate pressurized tanks. In situ measurements are hard to achieve during current delivery due to the severe electromagnetic conditions, and the lightning strike phenomenon on these structures is not yet fully investigated. To gain a better understanding of the physics involved, similarities in direct damage between lightning-struck samples and those subjected to pulsed lasers and an electron gun are analyzed. These analyses show the inability of a pure mechanical contribution to fully reproduce the shape of the delamination distribution of lightning strikes. Conversely, the similarities in effect and damage with the thermomechanical contribution of electron beam deposition are highlighted, particularly the increase in core delamination due to the paint and the apparent similarities in delamination distribution.
Citation: Aerospace
PubDate: 2025-03-14
DOI: 10.3390/aerospace12030235
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 236: Analysis of Observation Modes for
Space-Based Inverse Synthetic Aperture Lidar Based on Target
Characteristics
Authors: Ruimin Shen, Jingpeng Zhang, Lei Dong, Zhenzhen Zheng, Haiying Hu
First page: 236
Abstract: With the increasing congestion in orbital environments, on-orbit observation has become critical for spacecraft safety. This study investigated the observation performance of space-based inverse synthetic aperture lidar (ISAL) for monitoring on-orbit targets and space debris in geostationary Earth orbit (GEO) and low Earth orbit (LEO). Using STK simulations, the performances under fly-around and fly-by scenarios were evaluated based on three key parameters: minimum imaging time, pulse repetition frequency (PRF), and signal-to-noise ratio (SNR). The results reveal that while the GEO provided a high PRF and SNR for fly-around observations, longer imaging times limited its practical application, making the fly-by mode more suitable. In contrast, the LEO provided stable fly-around observations with lower system requirements, but the fly-by mode suffered from high PRF demands and a low SNR due to the high relative angular velocity of the target. This study further simulated fly-by observations for actual space debris in both the GEO and LEO, validating ISAL’s performance under different conditions. These findings offer valuable insights into the selection of observation modes and the optimization of ISAL’s performance in on-orbit target and debris monitoring, serving as a foundation for future space-based monitoring systems.
Citation: Aerospace
PubDate: 2025-03-14
DOI: 10.3390/aerospace12030236
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 237: Multi-Airport Capacity Decoupling Analysis
Using Hybrid and Integrated Surface–Airspace Traffic Modeling
Authors: Lei Yang, Yilong Wang, Sichen Liu, Mengfei Wang, Shuce Wang, Yumeng Ren
First page: 237
Abstract: The complexity and resource-sharing nature of traffic within multi-airport regions present significant challenges for air traffic management. This paper aims to develop a mesoscopic traffic model for exploring the traffic dynamics under coupled operations, and thus to conduct capacity decoupling analysis. We propose an integrated surface–airspace model. In the surface model, we utilize linear regression and random forest regression to model unimpeded taxiing time and taxiway network delays due to sparsity of ground traffic. In the airspace model, a dualized queuing network topology is constructed including a runway system, where the G(t)/GI/s(t) fluid queuing model is applied, and an inter-node traffic flow transmission mechanism is introduced to simulate airspace network traffic. Based on the hybrid and efficient model, we employ a Monte Carlo approach and use a quantile regression envelope model for capacity decoupling analysis. Using the Shanghai multi-airport region as a case study, the model’s performance is validated from the perspectives of operation time and traffic throughput. The results show that our model accurately represents traffic dynamics and estimates delays within an acceptable margin of error. The capacity decoupling analysis effectively captures the interdependence in traffic flow caused by resource sharing, both within a single airport and between airports.
Citation: Aerospace
PubDate: 2025-03-14
DOI: 10.3390/aerospace12030237
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 238: A Review of Simulations and Machine
Learning Approaches for Flow Separation Analysis
Authors: Xueru Hao, Xiaodong He, Zhan Zhang, Juan Li
First page: 238
Abstract: Flow separation is a fundamental phenomenon in fluid mechanics governed by the Navier–Stokes equations, which are second-order partial differential equations (PDEs). This phenomenon significantly impacts aerodynamic performance in various applications across the aerospace sector, including micro air vehicles (MAVs), advanced air mobility, and the wind energy industry. Its complexity arises from its nonlinear, multidimensional nature, and is further influenced by operational and geometrical parameters beyond Reynolds number (Re), making accurate prediction a persistent challenge. Traditional models often struggle to capture the intricacies of separated flows, requiring advanced simulation and prediction techniques. This review provides a comprehensive overview of strategies for enhancing aerodynamic design by improving the understanding and prediction of flow separation. It highlights recent advancements in simulation and machine learning (ML) methods, which utilize flow field databases and data assimilation techniques. Future directions, including physics-informed neural networks (PINNs) and hybrid frameworks, are also discussed to improve flow separation prediction and control further.
Citation: Aerospace
PubDate: 2025-03-14
DOI: 10.3390/aerospace12030238
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 239: Certification Gap Analysis for
Normal-Category and Large Hydrogen-Powered Airplanes
Authors: Jézégou, Almeida-Marino, O’Sullivan, Jiménez Carrasco, André, Gourinat
First page: 239
Abstract: The transition to hydrogen as an aviation fuel, as outlined in current decarbonization roadmaps, is expected to result in the entry into service of hydrogen-powered aircraft in 2035. To achieve this evolution, certification regulations are key enablers. Due to the disruptive nature of hydrogen aircraft technologies and their associated hazards, it is essential to assess the maturity of the existing regulatory framework for certification to ensure its availability when manufacturers apply for aircraft certification. This paper presents the work conducted under the Clean Aviation CONCERTO project to advance certification readiness by comprehensively identifying gaps in the current European regulations. Generic methodologies were developed for regulatory gap and risk analyses and applied to a hydrogen turbine aircraft with non-propulsive fuel cells as the APU. The gap analysis, conducted on certification specifications for large and normal-category airplanes as well as engines, confirmed the overall adequacy of many existing requirements. However, important gaps exist to appropriately address hydrogen hazards particularly concerning fire and explosion, hydrogen storage and fuel systems, crashworthiness, and occupant survivability. The paper concludes by identifying critical areas for certification and highlighting the need for complementary hydrogen phenomenology data, which are key to guiding future research and regulatory efforts for certification readiness maturation.
Citation: Aerospace
PubDate: 2025-03-14
DOI: 10.3390/aerospace12030239
Issue No: Vol. 12, No. 3 (2025)
- Aerospace, Vol. 12, Pages 139: Comparative Analysis on Modelling
Approaches for the Simulation of Fatigue Disbonding with Cohesive Zone
Models
Authors: Johan Birnie, Maria Pia Falaschetti, Enrico Troiani
First page: 139
Abstract: Adhesively bonded joints are essential in the aeronautical industry, offering benefits such as weight reduction and enhanced sustainability. However, certifying these joints is challenging due to unreliable methods for assessing their strength and the development of predictive models for fatigue-driven disbonding remains an ongoing effort. This manuscript presents the implementation and validation of a cohesive zone model for studying high-cycle fatigue disbonding under Mode I and Mixed-Mode loading. The model was integrated into the commercial finite element analysis software Abaqus using user-defined material subroutine (UMAT). Two modelling approaches were investigated: one replacing the adhesive with a cohesive layer, and the other incorporating a cohesive layer at the adhesive’s mid-plane while modelling its entire thickness, using both 2D and 3D techniques. Validation was conducted against experimental data from the literature that examined the influence of adhesive thickness on fatigue behaviour in DCB and CLS tests. The findings of this study confirm that the model accurately predicts fatigue disbonding across all cases examined. Additionally, the analysis reveals that modelling adhesive thickness plays a critical role in the simulation’s outcomes. Variations in adhesive thickness can significantly alter the crack growth behaviour, highlighting the importance of carefully considering this parameter in future assessments and applications.
Citation: Aerospace
PubDate: 2025-02-13
DOI: 10.3390/aerospace12020139
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 141: Ascent Trajectory Optimization Using
Second-Order Birkhoff Pseudospectral Methods
Authors: Xiaopeng Xue, Yujia Xie, Hui Zhou, Qinghai Gong, Dangjun Zhao
First page: 141
Abstract: This paper proposes a novel convex optimization framework for two-stage launch vehicle (TSLV) ascent trajectory planning from liftoff to orbit insertion, featuring two groundbreaking advancements over existing convex optimization methodologies: (1) an innovative second-order Birkhoff pseudospectral (BPS) method is developed that reduces the number of dynamic equality constraints by 50% compared to traditional PS methods, meanwhile, an augmented variable transcription technique is used to formulate inequality constraints; therefore, the sparsity ratio of the inequality matrix is reduced to less than 1%; (2) a new iterative solution strategy initialized by a few guesses is proposed to efficiently obtain the optimal solution. The framework is rigorously supported by theoretical convergence guarantees and validated through comprehensive numerical experiments. The numerical results demonstrate around a 50% reduction in computational time compared to the differential PS baseline method. With the significantly reduced computational cost, the proposed method exhibits strong potential for real-time onboard implementation in the future.
Citation: Aerospace
PubDate: 2025-02-13
DOI: 10.3390/aerospace12020141
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 142: An Evaluation of the Accuracy of Existing
Empirical and Semi-Empirical Methods for Predicting the Wing Mass of Large
Transport Aircraft
Authors: Odeh Dababneh, James T. Conway-Smith
First page: 142
Abstract: This paper investigates and evaluates the accuracy of various empirical and semi-empirical methods for predicting aircraft wing-structure mass. Eight methods were selected and analysed using data from large passenger-transport aircraft. The required technical data variables and specifications associated with these methods of wing-mass estimation were identified. When data were unavailable, sound engineering assumptions and judgments were applied as a last resort. The root mean square percentage error (RMSPE) was employed as the comparative indicator of accuracy to compute the average discrepancy between the predicted and actual wing-mass values. The resulting RMSPE values were 10% for the Kundu method, 13% for the Torenbeek II method, 15% for the Basgall method, and 17% for the Howe and LTH methods. According to the findings, the Kundu and Torenbeek II methods achieved the highest accuracy, with nonsignificant differences in their RMSPE values. Predicted wing mass was within [−12.5%, +11.7%] of the actual wing mass in approximately 62% of the study cases, which is adequate for most conceptual and preliminary aircraft-design purposes. Predictions were within [−22.3%, +20.6%] for about 25% of cases and within [−39.0%, +29.7%] for about 13% of cases. Furthermore, more complex methods did not enhance accuracy, as essential variables for these methods are often unavailable during the early design stage, rendering their inclusion less practical. Based on the collected and analysed data, a new updated formula for estimating aircraft wing mass is introduced. In comparison to the methods previously discussed, the new formula yields a superior overall RMSPE of 11%, significantly improving the accuracy of wing-mass estimation. Specifically, the results show an RMSPE of 6.5% for aircraft with a maximum takeoff mass exceeding 300,000 kg and 13% for those with a maximum takeoff mass below 300,000 kg. The refined method proves effective for wings with an aspect ratio of up to 10, offering reasonable accuracy during the conceptual design phase. However, some discrepancies still arise when this method is applied to unconventional aircraft.
Citation: Aerospace
PubDate: 2025-02-13
DOI: 10.3390/aerospace12020142
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 143: Multi-Objective Manoeuvring Optimization
for Multi-Satellite Responsive Earth Observation
Authors: Annarita Argirò, Nicola Cimmino, Giorgio Isoletta, Roberto Opromolla, Giancarmine Fasano
First page: 143
Abstract: Many space missions require that an area of interest on the ground is observed in a timely manner. Several approaches have been proposed in literature for this purpose, which involve modifying the ground track of an in-orbit satellite to overfly one or more Earth sites. Multi-satellite systems can clearly provide advantages for addressing this task in terms of responsiveness. In this context, this paper proposes a decision-making architecture to select the optimal manoeuvring or non-manoeuvring solution that enables a set of multiple sensor-equipped satellites in low Earth orbit to observe an area of interest in a timely fashion. For satellites that do not overfly the Earth site within the specified time period, dual coplanar impulsive manoeuvres are designed by applying a sensor-aware ground-track adjustment method. In particular, sensor footprints and percentage coverage of the assumed areas of interest are explicitly taken into account. A multi-objective optimization problem is then solved to determine which satellite provides the best solution to cover the area of interest in terms of fuel consumption (if ground-track adjustment is required) and time to overflight. Both simulated and real-world scenarios are considered to numerically validate the proposed methodology.
Citation: Aerospace
PubDate: 2025-02-13
DOI: 10.3390/aerospace12020143
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 144: A Combined Optimization Method for the
Transition Control Schedules of Aero-Engines
Authors: Wang Hao, Xiaobo Zhang, Baokuo Li, Zhanxue Wang, Dawei Li
First page: 144
Abstract: A well designed transition control schedule can enable the engine to quickly and smoothly transition from one operating state to another, thereby enhancing the maneuverability of the aircraft. Although traditional pointwise optimization methods are fast in solving the transition control schedules, their optimized control schedules suffer from fluctuation problems. While global optimization methods can suppress fluctuation problems, their slow solving speed makes them unsuitable for engineering applications. In this paper, a combined optimization method for the transition control schedules of aero-engines is proposed. This method divided the optimization of the control schedules into two layers. In the outer-layer optimization, the global optimization technique was utilized to suppress the fluctuation of geometrically adjustable parameters. In the inner-layer optimization, the pointwise optimization technique was adopted to quickly obtain the control schedule of fuel flow rate. Moreover, a construction method of non-uniform control points in the global optimization layer was proposed, which significantly reduced the number of control points that needed to be optimized; thus, improving the efficiency of global optimization. The optimization problem of the acceleration and deceleration control schedules of a mixed-flow turbofan engine was used to verify the effectiveness of the combined optimization method. The results show that, compared with the pointwise optimization method, the transition time optimized by the combined optimization method shows no obvious difference. The control schedules optimized by the combined optimization method are not only smooth but can also prevent some components from approaching their working boundaries.
Citation: Aerospace
PubDate: 2025-02-13
DOI: 10.3390/aerospace12020144
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 145: Autonomous Parafoil Flaring Control System
for eVTOL Aircraft
Authors: Stephen Doran, Toufik Souanef, James F. Whidborne
First page: 145
Abstract: Reducing landing kinetic energy during emergency landings is critical for minimising occupant injury in eVTOL aircraft. This study presents the development of an autonomous parafoil control system for impact point targeting and flare control. A model predictive controller for a six-degree-of-freedom parafoil and eVTOL payload model was designed incorporating an inner-loop flare controller for descent speed-based flare height adjustments and an outer-loop nonlinear model predictive control (MPC) to minimize line-of-sight error. Two guidance methods were explored: a standard fixed impact point approach and an adaptive method that adjusts the target point dynamically to account for horizontal travel during flaring. The standard method outperformed the uncontrolled system in 79.64% of cases, while the adaptive method achieved success in 40.73% of scenarios, with both methods maintaining vertical landing velocities below 8 m/s in all tested cases. Controller performance degraded under higher wind speeds and large control derivative variations, with the adaptive method position error attributed to flare distance estimation inaccuracies.
Citation: Aerospace
PubDate: 2025-02-14
DOI: 10.3390/aerospace12020145
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 146: Research on the Impact of the Sand and Dust
Ingestion Test on the Overall Performance of Turboshaft Engines
Authors: Qingping Wang, Wenchao Zhang, Xin Yuan, Yixuan Wang, Zhongliang Shen, Fei Wang
First page: 146
Abstract: Based on GJB 242A, a detailed experimental procedure for the sand and dust ingestion of a turboshaft engine was established. A specific type of turboshaft engine was used to conduct 54 h full-engine sand and dust ingestion experiments. This research studied the impact of sand and dust ingestion on the engine’s common operating line, power loss, specific fuel consumption, and gas turbine exhaust temperature, among other performance parameters. The experimental results indicate that under the same equivalent power conditions, the impact of short-term sand and dust ingestion on the engine’s common operating line is minimal; as the sand and dust ingestion time increases, the equivalent airflow decreases significantly, causing the engine’s common operating line to shift upward and the gas turbine exhaust temperature to rise, with the maximum increase reaching 27.9 °C. However, the impact of sand and dust ingestion on the gas turbine exhaust temperature at high power levels is relatively small. After completing the sand and dust ingestion test, the engine’s power loss at maximum continuous operation was approximately 11.33%, and the specific fuel consumption increased by about 6.05%. The power loss does not meet the requirement of being less than 10% as stipulated in GJB 242A. Based on the engine disassembly inspection results, subsequent improvement suggestions were proposed. The findings of this paper can provide a scientific and rational basis and reference for the sand and dust resistance design and sand ingestion testing of similar aero-engines.
Citation: Aerospace
PubDate: 2025-02-14
DOI: 10.3390/aerospace12020146
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 147: Scalability of eVTOL Systems: Insights from
Multi-Pad Configurations and CPN Analysis
Authors: Amir Qanbari, Jacek Skorupski
First page: 147
Abstract: Electric vertical takeoff and landing (eVTOL) technology can improve connectivity while minimizing reliance on traditional ground-based transportation systems. However, the rapid growth in eVTOL adoption brings challenges in managing landing pad operations and scheduling routes effectively. This study aims to analyze eVTOL landing operations and provide a framework for evaluating system performance under different configurations. Key objectives include (i) identifying bottlenecks in landing pad operations, (ii) proposing improvements to enhance scalability and efficiency through multi-route and multi-pad configurations, and (iii) assessing the impact of operational parameters, such as increased horizontal speed, on overall performance. A simulation analysis was conducted using an original model developed with colored, timed Petri net technology. This methodology aligns with the principles of probabilistic modeling and queuing systems. The experiments provided a comprehensive analysis of the factors influencing the scalability and efficiency of eVTOL operations. A key finding across all experiments is the identification of the “Landing Confirmed—Move to V” as a consistent bottleneck stage. While increasing routes and pads significantly alleviates arrival delays, it does not address identified bottlenecks, which require innovative solutions such as route optimization or speed enhancements. The results underscore the importance of a robust and adaptable framework to support the increasing demand for eVTOL traffic. Urban planners and policymakers can utilize these findings to prioritize the development of vertiports capable of supporting this expanding mode of transportation. The scalability demonstrated in this study validates the feasibility of eVTOL systems as a viable solution for urban mobility.
Citation: Aerospace
PubDate: 2025-02-15
DOI: 10.3390/aerospace12020147
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 148: Design of an Unsteady Smoke Simulation
System for the Airworthiness Verification of Smoke Detection in Aircraft
Cargo Compartments Based on the Adaptive Flow Control Method
Authors: Xiyuan Chen, Pengxiang Wang, Xinru Wang, Taian Zhao, Shanghua Guo, Jianzhong Yang
First page: 148
Abstract: Controlling the simulated smoke flow field is important in the airworthiness verification experiment for the smoke detection system in aircraft cargo compartments to accurately replicate actual fire smoke. In existing studies, the unsteady adjustment performance of the actuator to the simulated smoke flow field has not been comprehensively evaluated, and the model-based closed-loop flow control method encounters the unmodeled dynamics of the complex turbulent flow field. To solve the aforementioned problems, this study first uses the system identification method to obtain transfer function models for different actuation modes. Moreover, the transient adjustment capabilities of different actuation modes for the simulated smoke flow field are thoroughly evaluated. Then, an adaptive flow control law based on a radial basis function neural network is designed based on the selected actuating mode. Furthermore, closed-loop control experiments based on the adaptive control law are performed. The root locus of the transfer functions for two different actuation modes are compared, which reveals that adjusting the flow rate of simulated smoke exhibits a better stability margin than the actuation mode that regulates the upward momentum of simulated smoke. The experimental results in a full-scale mock-up of an aircraft cargo compartment demonstrate that the designed control law realizes dynamic tracking control with the unsteady concentration of actual fire smoke as the control target. Compared with that of PID control, the root mean square error of the control system is reduced by more than 40%. The simulated smoke under the closed-loop control obtains a light-transmission response equivalent to that of the actual fire smoke within a 5% error margin. The proposed closed-loop adaptive flow control method for simulated smoke approximates the unsteady process of actual fire smoke. It provides technical support for the replacement of actual fire smoke in the airworthiness verification experiment of smoke detection in aircraft cargo compartments.
Citation: Aerospace
PubDate: 2025-02-16
DOI: 10.3390/aerospace12020148
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 149: Research on Micro-Propulsion Performance of
Laser Ablation ADN-Based Liquid Propellant Enhanced by Chemical Energy
Authors: Luyun Jiang, Jifei Ye, Chentao Mao, Baosheng Du, Haichao Cui, Jianhui Han, Yongzan Zheng, Yanji Hong
First page: 149
Abstract: The vigorous development of micro–nano satellites urgently requires satellite-borne propulsion systems as support. Pulsed laser ablation micro-propulsion can meet these high demands. Ammonium dinitramide (ADN), as a green monopropellant, can serve as the working substance for laser ablation. This work investigated the micro-propulsion performance of liquid propellants composed of ADN and water with different ADN mass fractions, aiming to clarify the enhancement effect of chemical energy. Through the single-pulse impulse measurement, the results show that the 70 wt.% ADN had a maximum specific impulse of 167.55 s, a 19% increase compared to H2O. The established semi-empirical model of the micro-propulsion performance fits well with the experimental data and can effectively explain the variations in the patterns of the propulsion’s parameters. The chemical energy’s actual rate of contribution to the increase in the kinetic energy was positively correlated with the ADN’s mass fraction and negatively correlated with the laser energy, with an actual contribution rate of 36% for 70 wt.% ADN at a laser energy of 60 mJ. Furthermore, based on the relationship between the ablation efficiency, chemical-specific energy, and laser specific energy, it was found that the ablation efficiency can be improved by increasing the chemical specific energy and reducing the laser specific energy while ensuring the breakdown. This work provides a scientific approach to quantitatively analyze the enhancement in the propulsion’s performance by chemical energy in laser micro-ablation, which is expected to be extended to other energetic liquid propellants.
Citation: Aerospace
PubDate: 2025-02-16
DOI: 10.3390/aerospace12020149
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 150: Comprehensive Design and Experimental
Validation of Tethered Fixed-Wing Unmanned Aerial Vehicles
Authors: Changjin Yan, Jinchuan Yang, Donghui Zhang, Shu Zhang, Taihua Zhang
First page: 150
Abstract: The limited battery capacity currently restricts the flight duration of unmanned aerial vehicles (UAVs). Additionally, tethered rotorcraft UAVs suffer from low efficiency, and deploying tethered balloons presents significant challenges. Consequently, tethered fixed-wing UAVs exhibit highly promising development prospects. This study designs and constructs both simulation and physical models of a tethered fixed-wing UAV system. With the utilization of methods such as system identification and trust region algorithms, a comprehensive simulation model was developed, and its accuracy was rigorously validated. Furthermore, the feasibility of the system was confirmed through the integration of UAV hardware with a constructed power supply system, incorporating open source flight control software. The results demonstrate that the tethered fixed-wing UAV system is both feasible and reliable, offering rapid deployment capabilities and commendable flight stability. These findings highlight the potential of tethered fixed-wing UAVs as efficient and stable platforms for various applications, laying the groundwork for future research focused on developing more robust and adaptive control systems tailored to the specific challenges posed by tethered operations.
Citation: Aerospace
PubDate: 2025-02-16
DOI: 10.3390/aerospace12020150
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 151: A Comparative Study of Unsupervised Machine
Learning Methods for Anomaly Detection in Flight Data: Case Studies from
Real-World Flight Operations
Authors: Sameer Kumar Jasra, Gianluca Valentino, Alan Muscat, Robert Camilleri
First page: 151
Abstract: This paper provides a comparative study of unsupervised machine learning (ML) methods for anomaly detection in flight data monitoring (FDM). The study applies various unsupervised ML techniques to real-world flight data and compares the results to the current state-of-the-art flight data analysis techniques applied in industry. The results are validated by the industrial experts. The study finds that a hybrid Local Outlier Factor (LOF) approach provides significant advantages compared to the current state of the art and other ML techniques because it requires less hyperparameter tuning, reduces the number of false positives, provides an ability to establish trends amongst the entire fleet and has an ability to investigate anomalies at each timestep within every flight. Finally, the study provides an in-depth review for some of the cases highlighted by the hybrid LOF and discusses the particular cases providing insights from an academic and flight safety/operational point of view. The analysis conducted by the human expert regarding the outcomes produced by an ML technique is predominantly absent in scholarly research, thereby offering extra value. The study presents a compelling argument for transitioning from the current approach, based on analyzing occurrences through the exceedances of a threshold value, towards an ML-based method which provides a proactive nature of data analysis. The study shows that there is an untapped opportunity to process flight data and achieve valuable information for enhancing air transport safety and improved aviation operations.
Citation: Aerospace
PubDate: 2025-02-17
DOI: 10.3390/aerospace12020151
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 152: A Comparison of Reliability and Resource
Utilization of Radiation Fault Tolerance Mechanisms in Spaceborne
Electronic Systems
Authors: Changhyeon Kim, Dongmin Lee, Jongwhoa Na
First page: 152
Abstract: The advent of the New Space Era has significantly accelerated the development of space equipment systems using commercial off-the-shelf components. Field Programmable Gate Arrays are increasingly favored for their ability to be easily modified, which substantially reduces both development time and costs. However, their high susceptibility to space radiation poses a considerable risk of mission failure, potentially compromising system reliability in harsh space environments. To mitigate this vulnerability, the implementation of fault-tolerant mechanisms is essential. In this study, we applied eight distinct fault-tolerant mechanisms to various circuits and conducted a comparative analysis between two different categories: hardware redundancy and informational redundancy. This comparison was based on consistent criteria, specifically the Architectural Vulnerability Factor and resource consumption. Utilizing statistical fault injection tests and specialized software, we quantitatively measured structural vulnerability, power consumption, delay, and area. The results revealed that while the Hamming Code achieved the lowest structural vulnerability, it resulted in approximately fourfold increases in resource consumption. Conversely, Triple Modular Redundancy provided high reliability with relatively minimal resource usage. This research elucidates the trade-offs between reliability and resource overhead among different fault-tolerant mechanisms, highlighting the critical importance of selecting appropriate mechanisms based on system requirements to optimize the balance between reliability and resource utilization. Our analysis offers new insights essential for optimizing fault-tolerant mechanisms in space applications. Future work should explore more complex circuit architectures and diverse fault models to refine the selection criteria for fault-tolerant mechanisms tailored to real-world space missions.
Citation: Aerospace
PubDate: 2025-02-17
DOI: 10.3390/aerospace12020152
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 153: Numerical Simulation of the Gas Flow of
Combustion Products from Ignition in a Solid Rocket Motor Under Conditions
of Propellant Creep
Authors: Yin Zhang, Zhensheng Sun, Yu Hu, Yujie Zhu, Xuefeng Xia, Huang Qu, Bo Tian
First page: 153
Abstract: The development of modern solid rocket technology with high-performance and high-loading ratio propellants places higher requirements on the safety and stability of the solid rocket motor. The propellant of the solid rocket motor will creep during long-term vertical storage, which may adversely affect its regular operation. The ignition transient process is a critical phase in the operation of solid rocket motors. The Abaqus v.2022 finite element simulation software is used to analyze the ignition transient under propellant creep conditions and obtain the deformed combustion chamber profile. Then, we use a high-precision finite volume solver developed independently to simulate the flow field during the ignition process. In the simulation, we adopt the surface temperature of the propellant column reaching the ignition threshold as the ignition criterion, considering the heat transfer process of the propellant column instead of using the near-wall gas temperature to obtain the set temperature. Simulation results under different creep conditions reveal that the deformation of the propellant grains progressively intensifies as the solid rocket motor’s storage duration increases. This leads to a delayed initial ignition time of the propellant, an advancement of the overall ignition transient process, and an increased pressurization rate during ignition, which can affect the structure and regular operation of the motor. The research results provide design guidance and theoretical support for the design and life prediction of solid rocket motors.
Citation: Aerospace
PubDate: 2025-02-17
DOI: 10.3390/aerospace12020153
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 154: Numerical Predictions of
Low-Reynolds-Number Propeller Aeroacoustics: Comparison of Methods at
Different Fidelity Levels
Authors: Guangyuan Huang, Ankit Sharma, Xin Chen, Atif Riaz, Richard Jefferson-Loveday
First page: 154
Abstract: Low-Reynolds-number propeller systems have been widely used in aeronautical applications, such as unmanned aerial vehicles (UAV) and electric propulsion systems. However, the aerodynamic sound of the propeller systems is often significant and can lead to aircraft noise problems. Therefore, effective predictions of propeller noise are important for designing aircraft, and the different phases in aircraft design require specific prediction approaches. This paper aimed to perform a comparison study on numerical methods at different fidelity levels for predicting the aerodynamic noise of low-Reynolds-number propellers. The Ffowcs-Williams and Hawkings (FWH), Hanson, and Gutin methods were assessed as, respectively, high-, medium-, and low-fidelity noise models. And a coarse-grid large eddy simulation was performed to model the propeller aerodynamics and to inform the three noise models. A popular propeller configuration, which has been used in previous experimental and numerical studies on propeller noise, was employed. This configuration consisted of a two-bladed propeller mounted on a cylindrical nacelle. The propeller had a diameter of D=9″ and a pitch-to-diameter ratio of P/D=1, and was operated in a forward-flight condition with a chord-based Reynolds number of Re=4.8×104, a tip Mach number of M=0.231, and an advance ratio of J=0.485. The results were validated against existing experimental measurements. The propeller flow was characterized by significant tip vortices, weak separation over the leading edges of the blade suction sides, and small-scale vortical structures from the blade trailing edges. The far-field noise was characterized by tonal noise, as well as broadband noise. The mechanism of the noise generation and propagation were clarified. The capacities of the three noise modeling methods for predicting such propeller noise were evaluated and compared.
Citation: Aerospace
PubDate: 2025-02-18
DOI: 10.3390/aerospace12020154
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 155: Research on an Efficient Network Advanced
Orbiting Systems Comprehensive Multiplexing Algorithm Based on Elastic
Time Slots
Authors: Haowen Zhu, Zhen Zhang, Zhen Li, Jinwei Cheng, Zhonghe Jin
First page: 155
Abstract: To address the inadequacies of traditional Advanced Orbiting Systems (AOS) multiplexing algorithms in accommodating the networked and diverse transmission demands of space data, this paper proposes an efficient network AOS integrated multiplexing algorithm based on elastic time slots. The AOS network traffic is categorized into three types based on its characteristics, and a strongly scalable AOS integrated multiplexing model is established, which consists of a packet multiplexing layer, a virtual channel multiplexing layer, and a decision-making layer. For synchronous services, an isochronous frame generation algorithm and a periodic polling virtual channel scheduling algorithm are employed to meet the periodic transmission requirements. For asynchronous non-real-time services, a high-efficiency frame generation algorithm and a uniform queue length virtual channel scheduling algorithm are utilized to satisfy the high-efficiency transmission requirements. For asynchronous real-time services, an adaptive frame generation algorithm based on traffic prediction and a virtual channel scheduling algorithm based on comprehensive channel state are proposed. These algorithms optimize frame generation efficiency and dynamically calculate optimal scheduling results based on virtual channel scheduling status, transmission frame scheduling status, virtual channel priority status, and traffic prediction status, thereby meeting the high dynamics, low latency, and high efficiency transmission requirements. Additionally, a slot preemption-based elastic time slot scheduling strategy is proposed at the decision layer, which dynamically adjusts and optimizes the time slot allocation for the three types of traffic based on the current service request status and time slot occupancy status. Simulation results show that the proposed algorithm not only achieves lower average delay, fewer frame residuals, and higher transmission efficiency, but also maintains high stability under different working conditions, effectively meeting the transmission requirements of various types of space network traffic.
Citation: Aerospace
PubDate: 2025-02-18
DOI: 10.3390/aerospace12020155
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 156: Foundations for Teleoperation and Motion
Planning Towards Robot-Assisted Aircraft Fuel Tank Inspection
Authors: Adrián Ricárdez Ortigosa, Marc Bestmann, Florian Heilemann, Johannes Halbe, Lewe Christiansen, Rebecca Rodeck, Gerko Wende
First page: 156
Abstract: The aviation industry relies on continuous inspections to ensure infrastructure safety, particularly in confined spaces like aircraft fuel tanks, where human inspections are labor-intensive, risky, and expose workers to hazardous exposures. Robotic systems present a promising alternative to these manual processes but face significant technical and operational challenges, including technological limitations, retraining requirements, and economic constraints. Additionally, existing prototypes often lack open-source documentation, which restricts researchers and developers from replicating setups and building on existing work. This study addresses some of these challenges by proposing a modular, open-source framework for robotic inspection systems that prioritizes simplicity and scalability. The design incorporates a robotic arm and an end-effector equipped with three RGB-D cameras to enhance the inspection process. The primary contribution lies in the development of decentralized software modules that facilitate integration and future advancements, including interfaces for teleoperation and motion planning. Preliminary results indicate that the system offers an intuitive user experience, while also enabling effective 3D reconstruction for visualization. However, improvements in incremental obstacle avoidance and path planning inside the tank interior are still necessary. Nonetheless, the proposed robotic system promises to streamline development efforts, potentially reducing both time and resources for future robotic inspection systems.
Citation: Aerospace
PubDate: 2025-02-18
DOI: 10.3390/aerospace12020156
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 157: Investigation of the Thermal Vibration
Behavior of an Orthogonal Woven Composite Nozzle Based on RVE Analysis
Authors: Lin Wang, Xiaoniu Li, Congze Fan, Wenzhe Song, Yiwei Chen, Yufeng Jin, Xiaobo Han, Jinghua Zheng
First page: 157
Abstract: Carbon fiber-reinforced epoxy composites, known for their high specific stiffness, specific strength, and toughness are one of the primary materials used for composite nozzles in aerospace industries. The high temperature vibration behaviors of the composite nozzles, especially those that withstand internal pressures, are key to affecting their dynamic response and even failure during the service. This study investigates the changes in frequencies and the vibrational modes of the carbon fiber reinforced epoxy nozzles, focusing on a three-dimensional (3D) orthogonal woven composite, with high internal temperatures from 25 °C to 300 °C and non-uniform internal pressures, up to 5.4 MPa. By considering the temperature-sensitive parameters, including Young’s modulus, thermal conductivity, and thermal expansion coefficients, which are derived from a self-built representative volume element (RVE), the intrinsic frequencies and vibrational modes in composite nozzles were examined. Findings reveal that 2 nodal diameter (ND) and 3ND modes are influenced by Exx and Eyy while bending and torsion modes are predominantly affected by shear modulus. Temperature and internal pressure exhibit opposite effects on the modal frequencies. When the inner wall temperature rises from 25 °C to 300 °C, 2ND and 3ND frequencies decrease by an average of 30.39%, while bending and torsion frequencies decline by an average of 54.80%, primarily attributed to the decline modulus. Modal shifts were observed at ~150 °C, where the bending mode shifts to the 1st-order mode. More importantly, introducing non-uniform internal pressures induces the increase in nozzle stiffening in the xy-plane, leading to an apparent increase in the average 2ND and 3ND frequencies by 17.89% and 7.96%, while negligible changes in the bending and torsional frequencies. The temperature where the modal shifts were reduced to ~50 °C. The research performed in this work offers crucial insights for assessing the vibration life and safety design of hypersonic flight vehicles exposed to high-temperature thermal vibrations.
Citation: Aerospace
PubDate: 2025-02-18
DOI: 10.3390/aerospace12020157
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 158: Demonstration of Polyethylene Nitrous Oxide
Catalytic Decomposition Hybrid Thruster with Dual-Catalyst Bed Preheated
by Hydrogen Peroxide
Authors: Seungho Lee, Vincent Mario Pierre Ugolini, Eunsang Jung, Sejin Kwon
First page: 158
Abstract: Although various studies on nitrous oxide as a prospective green propellant have been recently explored, a polyethylene nitrous oxide catalytic decomposition hybrid thruster was barely demonstrated due to an inordinately high catalyst preheating time of a heater, which led to the destruction of components. Therefore, hydrogen peroxide was used as a preheatant, a substance to preheat, with a dual-catalyst bed. The thruster with polyethylene (PE) as a fuel, N2O as an oxidizer, H2O2 as the preheatant, Ru/Al2O3 as a catalyst for the oxidizer, and Pt/Al2O3 as a catalyst for the preheatant was arranged. A preheatant supply time of 10 s with a maximum catalyst bed temperature of more than 500 °C and without combustion and an oxidizer supply time of 20 s with a burning time of approximately 15 s were decided. Because the catalyst bed upstream part for decomposing the preheatant was far from the post-combustion chamber, the post-combustion chamber pressure increased and the preheatant mass flow rate decreased after a hard start during the preheatant supply time. Moreover, because the catalyst bed upstream part primarily contributed to preheating, the maximum catalyst bed temperature was less than the decomposition temperature of the preheatant during the preheatant supply time. Additionally, because the catalyst bed downstream part for decomposing the oxidizer was far from the post-combustion chamber, the post-combustion chamber pressure decreased and then increased during a transient state in the oxidizer supply time.
Citation: Aerospace
PubDate: 2025-02-18
DOI: 10.3390/aerospace12020158
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 159: Thickness Model of the Adhesive on
Spacecraft Structural Plate
Authors: Yanhui Guo, Peibo Li, Yanpeng Chen, Xinfu Chi, Yize Sun
First page: 159
Abstract: This paper establishes a physical model for the non-contact rotary screen coating process based on a spacecraft structural plate and proposes a theoretical expression for the adhesive thickness of the non-contact rotary screen coating. The thickness of the adhesive is a critical factor influencing the quality of the optical solar reflector (OSR) adhesion. The thickness of the adhesive layer depends on the equivalent fluid height and the ratio of the fluid flow rate to the squeegee speed below the squeegee. When the screen and fluid remain constant, the fluid flow rate below the squeegee depends on the pressure at the tip of the squeegee. The pressure is also a function related to the deformation characteristics and speed of the squeegee. Based on the actual geometric shape of the wedge-shaped squeegee, the analytical expression for the vertical displacement of the squeegee is obtained as the actual boundary of the flow field. The analytical expression for the deformation angle of the squeegee is used to solve the contact length between the squeegee and the rotary screen. It reduces the calculation difficulty compared with the previous method. Based on the theory of rheology and fluid mechanics, the velocity distribution of the fluid under the squeegee and the expression of the dynamic pressure at the tip of the squeegee were obtained. The dynamic pressure at the tip of the squeegee is a key factor for the adhesive to pass through the rotary screen. According to the continuity equation of the fluid, the theoretical thickness expression of the non-contact rotary screen coating is obtained. The simulation and experimental results show that the variation trend of coating thickness with the influence of variables is consistent. Experimental and simulation errors compared to theoretical values are less than 5%, which proves the rationality of the theoretical expression of the non-contact rotary screen coating thickness under the condition of considering the actual squeegee deformation. The existence of differences proves that a small part of the colloid remains on the rotary screen during the colloid transfer process. The expression parameterizes the rotary screen coating model and provides a theoretical basis for the design of automatic coating equipment.
Citation: Aerospace
PubDate: 2025-02-19
DOI: 10.3390/aerospace12020159
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 160: Research on Disturbance Compensation
Control and Parameter Identification of a Multiple Air-Bearing Planar
Air-Floating Platform Based on ADRC
Authors: Chuanxiao Xu, Guohua Kang, Junfeng Wu, Zhen Li, Xinyong Tao, Jiayi Zhou, Jiaqi Wu
First page: 160
Abstract: The spacecraft microgravity simulation air-bearing platform is a crucial component of the spacecraft ground testing system. Special disturbances, such as the flatness and roughness of the contact surface between the air bearings and the granite platform, increasingly affect the control accuracy of the simulation experiment as the number of air bearings increases. To address this issue, this paper develops a novel compensation control system based on Active Disturbance Rejection Control (ADRC), which estimates and compensates for the disturbing forces and moments caused by the roughness and levelness of the contact surface, thereby improving the control precision of the spacecraft ground simulation system. A dynamic model of the multi-air-bearing platform under disturbance is established. A cascade ADRC algorithm based on the Linear Extended State Observer (LESO) is designed. The Gauss–Newton iteration method is used to identify the parameters of the sliding friction coefficient and the tilt angle of the air-bearing platform. A full-physics simulation experimental platform for spacecraft with rotor-based propulsion is constructed, and the proposed algorithm is validated. The experimental results show that on a marble surface with a flatness of grade 00, an overall tilt angle of 0–1 degrees, and a surface friction coefficient of 0–0.01, the position control accuracy for the simulated spacecraft can reach 1.5 cm, and the attitude control accuracy can reach 1°. Under ideal conditions, the identification accuracy for the contact surface friction coefficient is 2 × 10−4, and the recognition accuracy for the overall levelness of the marble surface can reach 1 × 10−3, laying the foundation for high-precision ground simulation experiments of spacecraft in multi-air-bearing scenarios.
Citation: Aerospace
PubDate: 2025-02-19
DOI: 10.3390/aerospace12020160
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 161: Research on the Damage Characteristics of a
UAV Flight Control System Irradiated by a Continuous Laser
Authors: Le Liu, Chengyang Xu, Sheng Cai, Jiamin Wang, Dandan Huang, Kun Yang, Changbin Zheng, Jin Guo
First page: 161
Abstract: To improve laser anti-UAV technology and UAV laser protection capabilities, research on continuous laser damage to a UAV flight control system has been carried out. Combining waveform and function monitoring, the performance of the flight control system under laser irradiation was observed in real time, and the temperature and ablation process were recorded, which were used to analyze its damage characteristics and thresholds. Our experimental results show that the flight control system had two damage modes: temporary failure and permanent damage. Temporary failure had a temperature threshold, which was on average 450.85 K. All temporarily failed flight control system functions could be restored after cooling and a manual restart, but permanently damaged flight control systems could not be manually restarted. This experiment showed that, within K. All temporarily failed flight control system functions could be restored after cooling and a manual restart, but permanently damaged flight control systems could not be manually restarted. This experiment showed that, within 10 s, the power density required for temporary failure and permanent damage to the flight control system was 28.4 W/cm2 and 42.6 W/cm2, respectively. The power density required for permanent damage was 82.0 W/cm2 within 16 s if the flight control system was encapsulated with aluminum alloy. Based on the circuit fault diagnosis of the flight control system samples that has been permanently damaged, the laser’s thermal effects damaged the diodes and linear regulators, ultimately rendering the flight control system unable to be manually restarted.
Citation: Aerospace
PubDate: 2025-02-19
DOI: 10.3390/aerospace12020161
Issue No: Vol. 12, No. 2 (2025)
- Aerospace, Vol. 12, Pages 162: Aeroacoustic Study of Synchronized Rotors
Authors: Fabio Del Duchetto, Tiziano Pagliaroli, Paolo Candeloro, Karl-Stéphane Rossignol, Jianping Yin
First page: 162
Abstract: The main goal of the present study is to explore the noise mitigation potential using an active control strategy based on rotor phase synchronization. This work is focused on the effects of the inflow velocity on the noise interference effect. The inflow velocity does not affect the phase at which the interference phenomenon is observed, as expected. On the other hand, the intensity of the pressure fluctuations is influenced by the inflow velocity for all of the rotor phase shift conditions investigated. Specifically, as the inflow velocity increases, maintaining a constant rotational speed, in the Overall Sound Pressure Level graphs, a reduction of approximately 10 dB is observed. This effect also applies to cases of destructive interference, highlighting the remarkable versatility of this noise reduction technique.
Citation: Aerospace
PubDate: 2025-02-19
DOI: 10.3390/aerospace12020162
Issue No: Vol. 12, No. 2 (2025)
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