Pub Date : 2025-06-01DOI: 10.1016/j.paerosci.2025.101095
Max F. Platzer
This special issue on unidentified aerospace-undersea phenomena (UAP) contains five papers that attempt to provide an overview of the status of past and present UAP events and research projects. It also addresses the question whether the aerospace science and engineering community needs to initiate a UAP monitoring effort that is based on rigorous scientific evaluation criteria.
{"title":"Unidentified aerospace-undersea phenomena (UAP) status and outlook","authors":"Max F. Platzer","doi":"10.1016/j.paerosci.2025.101095","DOIUrl":"10.1016/j.paerosci.2025.101095","url":null,"abstract":"<div><div>This special issue on unidentified aerospace-undersea phenomena (UAP) contains five papers that attempt to provide an overview of the status of past and present UAP events and research projects. It also addresses the question whether the aerospace science and engineering community needs to initiate a UAP monitoring effort that is based on rigorous scientific evaluation criteria.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"156 ","pages":"Article 101095"},"PeriodicalIF":11.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.paerosci.2025.101098
Jacques F. Vallée , Luc Dini , Geoffrey Mestchersky
An exceptional observation of an anomalous object, recorded as ‘unidentified’ by the US Air Force and in the1969 final report of the University of Colorado (“Condon”) study of UAPs, has been re-examined by a Franco-American scientific team.
The observation took place on the evening of December 30, 1966, on an isolated highway traversing a forest near Haynesville, Louisiana. Early in 1967 the main witness, a professor of atomic physics named Louie A. Galloway, reported the case to Project Blue Book of the USAF. Pro-active investigation by one of the authors (JV) brought it to the attention of Professor Edward Condon, himself a noted atomist who had worked under Project Manhattan. Dr. Condon and his team had just begun an official re-examination of UFO (UAP) phenomena under funding of the US Air Force.
The case, which centered on a well-defined luminous object at ground level, led to energy estimates from 500 to 1400 MW, in the range of a small modern nuclear power plant. Significantly, it was one of a number of cases carried as ‘Unidentified’ in Dr. Condon's final report to the National Academy of Sciences in 1969.
Subsequent to that Academy report, significant work was continued at the site by civilian investigators who confirmed the data, augmented by night photography flights. The team returned to the area with the primary witness, located the exact place of observation and gathered new data, notably about the nature of burns evidenced on the trees, which had not been available to Dr. Condon and his assistants.
Samples of the burned and intact bark were obtained by our own team, and they were preserved until it became possible to properly analyze the material.
The burn analysis data presented here was obtained at the laboratories of the French Atomic Energy Commission in Saclay, France. We present our results with the understanding that the study will benefit from further discussion within the larger scientific community.
美国空军在1969年科罗拉多大学（“Condon”）研究不明飞行物的最终报告中记录了对一个异常物体的特殊观察，并将其记录为“不明飞行物”，一个法美科学小组对此进行了重新研究。这次观测发生在1966年12月30日的晚上，地点是路易斯安那州海恩斯维尔附近一条穿过森林的公路上。1967年初，主要的目击者，一位名叫路易·a·加洛韦的原子物理学教授，向美国空军的蓝皮书计划报告了这件事。其中一位作者的积极调查引起了爱德华·康登教授的注意，他本人也是一位著名的原子学家，曾在曼哈顿计划下工作过。在美国空军的资助下，康登博士和他的团队刚刚开始对不明飞行物（UAP）现象进行官方重新检查。该案例以地面上一个明确的发光物体为中心，导致能量估计在500到1400兆瓦之间，相当于一个小型现代核电站的范围。值得注意的是，这是康登博士1969年提交给美国国家科学院（National Academy of Sciences）的最终报告中被列为“身份不明”的众多病例之一。在学院报告之后，文职调查人员在现场继续进行了大量工作，他们证实了数据，并通过夜间摄影飞行加以补充。该小组带着主要证人回到了该地区，找到了确切的观察地点，并收集了新的数据，特别是关于树木烧伤的性质，康登博士和他的助手们没有得到这些数据。我们自己的团队获得了烧焦和完整树皮的样本，并将它们保存起来，直到有可能对材料进行适当的分析。这里展示的燃烧分析数据是在法国萨克莱的法国原子能委员会实验室获得的。我们提出我们的研究结果的理解是，这项研究将受益于更大的科学界的进一步讨论。
{"title":"Estimates of radiative energy values in ground-level observations of an unidentified aerial phenomenon: New physical data","authors":"Jacques F. Vallée , Luc Dini , Geoffrey Mestchersky","doi":"10.1016/j.paerosci.2025.101098","DOIUrl":"10.1016/j.paerosci.2025.101098","url":null,"abstract":"<div><div>An exceptional observation of an anomalous object, recorded as ‘unidentified’ by the US Air Force and in the1969 final report of the University of Colorado (“Condon”) study of UAPs, has been re-examined by a Franco-American scientific team.</div><div>The observation took place on the evening of December 30, 1966, on an isolated highway traversing a forest near Haynesville, Louisiana. Early in 1967 the main witness, a professor of atomic physics named Louie A. Galloway, reported the case to Project Blue Book of the USAF. Pro-active investigation by one of the authors (JV) brought it to the attention of Professor Edward Condon, himself a noted atomist who had worked under Project Manhattan. Dr. Condon and his team had just begun an official re-examination of UFO (UAP) phenomena under funding of the US Air Force.</div><div>The case, which centered on a well-defined luminous object at ground level, led to energy estimates from 500 to 1400 MW, in the range of a small modern nuclear power plant. Significantly, it was one of a number of cases carried as ‘Unidentified’ in Dr. Condon's final report to the National Academy of Sciences in 1969.</div><div>Subsequent to that Academy report, significant work was continued at the site by civilian investigators who confirmed the data, augmented by night photography flights. The team returned to the area with the primary witness, located the exact place of observation and gathered new data, notably about the nature of burns evidenced on the trees, which had not been available to Dr. Condon and his assistants.</div><div>Samples of the burned and intact bark were obtained by our own team, and they were preserved until it became possible to properly analyze the material.</div><div>The burn analysis data presented here was obtained at the laboratories of the French Atomic Energy Commission in Saclay, France. We present our results with the understanding that the study will benefit from further discussion within the larger scientific community.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"156 ","pages":"Article 101098"},"PeriodicalIF":11.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.paerosci.2025.101100
Alex Ellery
Interstellar missions will require a high degree of autonomy mediated through artificial intelligence (AI). All interstellar missions are characterised by 50-100-year transits to extrasolar systems. High system availability demands that interstellar spacecraft are self-repairable imposing significant demands on onboard intelligence. We review the current status of artificial intelligence to assess its capabilities in providing such autonomy. In particular, we focus on hybrid AI methods as these appear to offer the richest capabilities in offsetting weaknesses inherent in paradigmic approaches. Symbolic manipulation systems offer logical and comprehensible rationality with predictable behaviours but are brittle beyond their specific applications (a charge that may be levelled at neural networks unless the transfer learning problem can be resolved). More modern approaches to expert systems include Bayesian networks that incorporate probabilistic treatment to accommodate uncertainty. Artificial neural networks are fundamentally different. They are opaque to analysis but potentially offer greater adaptability in application by virtue of their ability to learn. Indeed, deep machine learning is a variation on neural networks with unsupervised neural front ends and supervised neural back ends. Reinforcement learning offers a promising approach for learning directly from the environment. There are inherent weaknesses in neural approaches regarding their hidden mechanisms rendering their distributed representations opaque to analysis. Hybridising symbolic processing techniques with artificial neural networks appears to offer the advantages of both. Human cognition appears to implement both neural learning and symbolic processing. There are several approaches to such hybridisation that we explore including knowledge-based artificial neural networks, fuzzy neural networks, Bayesian methods such as Markov logic networks and genetic methods such as learning classifier systems. Markov logic networks propose a natural correlation between Bayesian probability and neural weights but mapping representation of symbols into switching neurons is less clear (though vector symbolic architectures present an approach) while learning classifier systems are reinforcement learning methods that are promising for interacting with the physical world. We conclude that current AI may not yet be up to the task of interstellar transits and flybys let alone for physical interaction with unknown planetary environments. Certainly, AI is incapable of interactive encounters with extraterrestrial intelligence.
{"title":"The state of hybrid artificial intelligence for interstellar missions","authors":"Alex Ellery","doi":"10.1016/j.paerosci.2025.101100","DOIUrl":"10.1016/j.paerosci.2025.101100","url":null,"abstract":"<div><div>Interstellar missions will require a high degree of autonomy mediated through artificial intelligence (AI). All interstellar missions are characterised by 50-100-year transits to extrasolar systems. High system availability demands that interstellar spacecraft are self-repairable imposing significant demands on onboard intelligence. We review the current status of artificial intelligence to assess its capabilities in providing such autonomy. In particular, we focus on hybrid AI methods as these appear to offer the richest capabilities in offsetting weaknesses inherent in paradigmic approaches. Symbolic manipulation systems offer logical and comprehensible rationality with predictable behaviours but are brittle beyond their specific applications (a charge that may be levelled at neural networks unless the transfer learning problem can be resolved). More modern approaches to expert systems include Bayesian networks that incorporate probabilistic treatment to accommodate uncertainty. Artificial neural networks are fundamentally different. They are opaque to analysis but potentially offer greater adaptability in application by virtue of their ability to learn. Indeed, deep machine learning is a variation on neural networks with unsupervised neural front ends and supervised neural back ends. Reinforcement learning offers a promising approach for learning directly from the environment. There are inherent weaknesses in neural approaches regarding their hidden mechanisms rendering their distributed representations opaque to analysis. Hybridising symbolic processing techniques with artificial neural networks appears to offer the advantages of both. Human cognition appears to implement both neural learning and symbolic processing. There are several approaches to such hybridisation that we explore including knowledge-based artificial neural networks, fuzzy neural networks, Bayesian methods such as Markov logic networks and genetic methods such as learning classifier systems. Markov logic networks propose a natural correlation between Bayesian probability and neural weights but mapping representation of symbols into switching neurons is less clear (though vector symbolic architectures present an approach) while learning classifier systems are reinforcement learning methods that are promising for interacting with the physical world. We conclude that current AI may not yet be up to the task of interstellar transits and flybys let alone for physical interaction with unknown planetary environments. Certainly, AI is incapable of interactive encounters with extraterrestrial intelligence.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"156 ","pages":"Article 101100"},"PeriodicalIF":11.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.paerosci.2025.101096
Max F. Platzer
{"title":"On the need for rigorous scientific research on unidentified aerial phenomena (UAP)","authors":"Max F. Platzer","doi":"10.1016/j.paerosci.2025.101096","DOIUrl":"10.1016/j.paerosci.2025.101096","url":null,"abstract":"","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"156 ","pages":"Article 101096"},"PeriodicalIF":11.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.paerosci.2025.101093
Xiaobing Zhang , Zekang Wang
The remarkable feature of the flow field of compressible aerodynamics is the shock wave structure. The prominent feature of the current leading edge flow field of supersonic and hypersonic aircraft is the bow shock wave structure, which is the root cause of high-speed aircraft wave resistance and extreme aerodynamic heating. Research and advancement of new aerodynamic resistance mitigation methods and thermal protection systems for supersonic and hypersonic aircraft have received widespread attention from researchers from various countries. This article reviews the mechanical spike structure and two active flow control methods: counterflowing jet and energy deposition, focusing on the research progress of various combined flow control methods in recent years. Their mechanisms of action, respective advantages and challenges for future development are introduced in detail. Research on supersonic flow field aerodynamic resistance mitigation and thermal protection systems will surely promote the development of high-speed aircraft in terms of increasing flight distance, reducing weight and protecting the leading-edge structure to achieve lightweight aircraft.
{"title":"Thermal protection and drag reduction induced by flow control devices in supersonic/hypersonic flows: A review","authors":"Xiaobing Zhang , Zekang Wang","doi":"10.1016/j.paerosci.2025.101093","DOIUrl":"10.1016/j.paerosci.2025.101093","url":null,"abstract":"<div><div>The remarkable feature of the flow field of compressible aerodynamics is the shock wave structure. The prominent feature of the current leading edge flow field of supersonic and hypersonic aircraft is the bow shock wave structure, which is the root cause of high-speed aircraft wave resistance and extreme aerodynamic heating. Research and advancement of new aerodynamic resistance mitigation methods and thermal protection systems for supersonic and hypersonic aircraft have received widespread attention from researchers from various countries. This article reviews the mechanical spike structure and two active flow control methods: counterflowing jet and energy deposition, focusing on the research progress of various combined flow control methods in recent years. Their mechanisms of action, respective advantages and challenges for future development are introduced in detail. Research on supersonic flow field aerodynamic resistance mitigation and thermal protection systems will surely promote the development of high-speed aircraft in terms of increasing flight distance, reducing weight and protecting the leading-edge structure to achieve lightweight aircraft.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"155 ","pages":"Article 101093"},"PeriodicalIF":11.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The recent groundbreaking advancements in Mach 4–7 combustion organization technology have paved the way for a significant expansion of the operational envelope for scramjets, enabling them to reach higher Mach numbers. By meticulously designing the compression ratio of the hypersonic inlet, the flow parameters at the entrance of the combustor can be effectively managed, thereby facilitating the autoignition of the reactant gas mixture. However, the challenge of achieving efficient combustion in a hypersonic environment escalates considerably. This paper delves into the intricacies of the reacting flows within high-Mach-number scramjets through a comprehensive literature review, segmented into three key technical fields. Firstly, the real gas effects in high-temperature hypersonic flows are given more attention, offering an in-depth examination of the physical and chemical properties of nonequilibrium flows. It also elucidates the sources of internal resistance in the flow path and the mechanisms behind the drag reduction achieved through boundary layer combustion. Subsequently, the paper synthesizes various strategies to enhance the efficiency of fuel/air mixing and combustion. These include advancing the injection position to prolong the fuel's flow residence time, employing porous, pulse injection, and oxygen supplementation techniques to boost the local premixing of combustible gases, and utilizing vortex generators to create large-scale streamwise vortices or recirculation zones that foster mixing. In summary, the paper provides an overview of combustion stabilization modes and mechanisms controlled by mixing in different combustion configurations. Building on this analysis, it uncovers the significant influence of thermochemical nonequilibrium effects on flow, ignition and flame stabilization, shedding light on the complexities of scramjets at high Mach numbers.
{"title":"Research progress of the flow and combustion organization for the high-Mach-number scramjet: From Mach 8 to 12","authors":"Chaoyang Liu, Junding Ai, Jincheng Zhang, Xin Li, Zijian Zhao, Wei Huang","doi":"10.1016/j.paerosci.2025.101094","DOIUrl":"10.1016/j.paerosci.2025.101094","url":null,"abstract":"<div><div>The recent groundbreaking advancements in Mach 4–7 combustion organization technology have paved the way for a significant expansion of the operational envelope for scramjets, enabling them to reach higher Mach numbers. By meticulously designing the compression ratio of the hypersonic inlet, the flow parameters at the entrance of the combustor can be effectively managed, thereby facilitating the autoignition of the reactant gas mixture. However, the challenge of achieving efficient combustion in a hypersonic environment escalates considerably. This paper delves into the intricacies of the reacting flows within high-Mach-number scramjets through a comprehensive literature review, segmented into three key technical fields. Firstly, the real gas effects in high-temperature hypersonic flows are given more attention, offering an in-depth examination of the physical and chemical properties of nonequilibrium flows. It also elucidates the sources of internal resistance in the flow path and the mechanisms behind the drag reduction achieved through boundary layer combustion. Subsequently, the paper synthesizes various strategies to enhance the efficiency of fuel/air mixing and combustion. These include advancing the injection position to prolong the fuel's flow residence time, employing porous, pulse injection, and oxygen supplementation techniques to boost the local premixing of combustible gases, and utilizing vortex generators to create large-scale streamwise vortices or recirculation zones that foster mixing. In summary, the paper provides an overview of combustion stabilization modes and mechanisms controlled by mixing in different combustion configurations. Building on this analysis, it uncovers the significant influence of thermochemical nonequilibrium effects on flow, ignition and flame stabilization, shedding light on the complexities of scramjets at high Mach numbers.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"155 ","pages":"Article 101094"},"PeriodicalIF":11.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-01DOI: 10.1016/j.paerosci.2025.101092
Shraddha C. , Pankaj Priyadarshi , Devendra Prakash Ghate
Launch vehicle recovery technology has witnessed considerable advancement in recent years. This not only reduces the cost of access to space but also its rapid exploration. This paper gives a historical overview, surveys the launch vehicle recovery techniques, classifies based on multiple criteria, lists the advantages and disadvantages of each recovery technique, discusses the key phases involved during the recovery and lists the strategies adopted by various missions for each phase. It also gives an overview of the cost implications of launch vehicle recovery and reuse as reported in the open literature.
{"title":"A survey of launch vehicle recovery techniques","authors":"Shraddha C. , Pankaj Priyadarshi , Devendra Prakash Ghate","doi":"10.1016/j.paerosci.2025.101092","DOIUrl":"10.1016/j.paerosci.2025.101092","url":null,"abstract":"<div><div>Launch vehicle recovery technology has witnessed considerable advancement in recent years. This not only reduces the cost of access to space but also its rapid exploration. This paper gives a historical overview, surveys the launch vehicle recovery techniques, classifies based on multiple criteria, lists the advantages and disadvantages of each recovery technique, discusses the key phases involved during the recovery and lists the strategies adopted by various missions for each phase. It also gives an overview of the cost implications of launch vehicle recovery and reuse as reported in the open literature.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"155 ","pages":"Article 101092"},"PeriodicalIF":11.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01DOI: 10.1016/j.paerosci.2025.101081
Michael Sidebottom , Lee Margetts , Mostafa R.A. Nabawy
The smallest example of powered flight currently known to humans is that of miniature insects, with wing lengths typically no greater than 1 mm. Flight in this domain is characterised by Reynolds numbers of the order of 10, meaning that viscous flow effects are more pronounced and, consequently, representative lift-to-drag ratios are significantly low. Most notably, at miniature scales, there is a transition from insects with wings made of continuous membranes to wings predominantly made up of bristled appendages. Yet, there remains very little understanding of how the structural arrangement of bristled wings interacts with the aerodynamics. In addition to their unique wing morphologies, the wing kinematics employed by miniature insects are also distinct. While flight is classically characterised via a lift force as the primary component for counteracting weight, miniature insects use swimming-like flapping profiles in which drag plays a distinctly more pronounced role in opposing gravity. Relative to the broader field of insect aerodynamics, the miniature domain has only recently begun to receive widespread attention from aerodynamicists, yet developing our understanding in the miniature field provides an opportunity to advance our capacity to inform the future design of miniature flying robots. To that end, the purpose of this review is to collate together the progress made thus far, in order to generate a perspective with regards to our current understanding of flight in the miniature domain.
{"title":"The aerodynamics of miniature insect flight","authors":"Michael Sidebottom , Lee Margetts , Mostafa R.A. Nabawy","doi":"10.1016/j.paerosci.2025.101081","DOIUrl":"10.1016/j.paerosci.2025.101081","url":null,"abstract":"<div><div>The smallest example of powered flight currently known to humans is that of miniature insects, with wing lengths typically no greater than 1 mm. Flight in this domain is characterised by Reynolds numbers of the order of 10, meaning that viscous flow effects are more pronounced and, consequently, representative lift-to-drag ratios are significantly low. Most notably, at miniature scales, there is a transition from insects with wings made of continuous membranes to wings predominantly made up of bristled appendages. Yet, there remains very little understanding of how the structural arrangement of bristled wings interacts with the aerodynamics. In addition to their unique wing morphologies, the wing kinematics employed by miniature insects are also distinct. While flight is classically characterised via a lift force as the primary component for counteracting weight, miniature insects use swimming-like flapping profiles in which drag plays a distinctly more pronounced role in opposing gravity. Relative to the broader field of insect aerodynamics, the miniature domain has only recently begun to receive widespread attention from aerodynamicists, yet developing our understanding in the miniature field provides an opportunity to advance our capacity to inform the future design of miniature flying robots. To that end, the purpose of this review is to collate together the progress made thus far, in order to generate a perspective with regards to our current understanding of flight in the miniature domain.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"154 ","pages":"Article 101081"},"PeriodicalIF":11.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-01DOI: 10.1016/j.paerosci.2025.101082
Tao Ma , Hanan Lu , Qiushi Li
The distributed propulsion system has a significant potential for reducing the fuel consumption, noise and pollution emissions for the next-generation aircraft and become a current hot research topic. As the core component of the distributed propulsion system, the boundary layer ingestion fan has been continuously operating under the distorted inflow conditions, which largely degrades the aerodynamic performance of the fan itself. In turn, the degradation of the BLI fan performance will have a severe impact on the overall aerodynamic benefits achievement of the aircraft. This paper has conducted a systematic review of the boundary layer ingestion fan. Firstly, the aerodynamic benefits of BLI propulsion system has been overviewed. Then, different types of BLI fan based propulsion configurations have been introduced and the distinguished features of the distorted inflows for each configuration are analyzed in detail. Thirdly, the fan aerodynamic responses to the BLI distorted inflow are given and the influences of the BLI inflow distortion on the fan aerodynamic performances and internal flow fields are fully investigated. Subsequently, the potential performance evaluation methods, mainly the low-order computational approaches, used in the preliminary design stage of the fan have been comprehensively overviewed. Finally, the research works concerning the attempts for the fan/compressor design under non-uniform inflow condition are reviewed and some perspectives of the distortion-tolerant BLI fan design in the future have also been presented. The motivation of this work is to provide some useful guidelines for the upcoming research works concerning the BLI fan based propulsion systems.
{"title":"A systematic review of boundary layer ingestion (BLI) fan: Current Status and future perspectives","authors":"Tao Ma , Hanan Lu , Qiushi Li","doi":"10.1016/j.paerosci.2025.101082","DOIUrl":"10.1016/j.paerosci.2025.101082","url":null,"abstract":"<div><div>The distributed propulsion system has a significant potential for reducing the fuel consumption, noise and pollution emissions for the next-generation aircraft and become a current hot research topic. As the core component of the distributed propulsion system, the boundary layer ingestion fan has been continuously operating under the distorted inflow conditions, which largely degrades the aerodynamic performance of the fan itself. In turn, the degradation of the BLI fan performance will have a severe impact on the overall aerodynamic benefits achievement of the aircraft. This paper has conducted a systematic review of the boundary layer ingestion fan. Firstly, the aerodynamic benefits of BLI propulsion system has been overviewed. Then, different types of BLI fan based propulsion configurations have been introduced and the distinguished features of the distorted inflows for each configuration are analyzed in detail. Thirdly, the fan aerodynamic responses to the BLI distorted inflow are given and the influences of the BLI inflow distortion on the fan aerodynamic performances and internal flow fields are fully investigated. Subsequently, the potential performance evaluation methods, mainly the low-order computational approaches, used in the preliminary design stage of the fan have been comprehensively overviewed. Finally, the research works concerning the attempts for the fan/compressor design under non-uniform inflow condition are reviewed and some perspectives of the distortion-tolerant BLI fan design in the future have also been presented. The motivation of this work is to provide some useful guidelines for the upcoming research works concerning the BLI fan based propulsion systems.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"154 ","pages":"Article 101082"},"PeriodicalIF":11.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Contemporary trends in Uncrewed Aircraft Systems Traffic Management (UTM) and Advanced Air Mobility (AAM) are redefining low-altitude airspace operations, particularly in urban and suburban settings where traditional airspace management approaches are inadequate to support the predicted air transport demands. To address these challenges, the development of an integrated Low-Altitude Airspace Management (LAAM) framework is seen as an essential next step, requiring new flight systems and infrastructure tailored to the distinct challenges of these environments. Cyber technologies, including automation and Artificial Intelligence (AI), play a crucial role in LAAM by integrating data from Communication, Navigation, and Surveillance (CNS) systems to support real-time and automated decision-making for separation assurance and flow management. While human operators and social interactions retain a very important role in LAAM collaborative decision-making processes, the reliance on automation is expected to continue growing, driven by the need to effectively manage the challenges arising from the increasing number and diversity of highly automated and uncrewed aircraft. Regulatory frameworks must adapt to accommodate the unique characteristics of AAM operations, ensuring the adequacy of safety standards and airspace regulations. In particular, airspace design is bound to evolve to accommodate Vertical/Short Take-off and Landing (V/STOL) aircraft’s distinct capabilities and requirements. The deployment of AI in safety-critical systems will require rigorous verification, validation, and certification processes to ensure reliability and trustworthiness. To address these complex and interrelated challenges, a harmonized LAAM Concept of Operations (CONOPS) is needed, which should encapsulate both UTM and emerging AAM requirements, while clearly specifying the role of human operators for various levels of automation. Additionally, new system functionalities should be developed to enhance human-machine teaming by focussing on CNS performance-based airspace modeling and dynamic airspace management. Based on these premises, an integrated approach to Multi-Domain Traffic Management (MDTM) is emerging, with promising future perspectives for the safe, efficient and sustainable operation of highly automated and autonomous flight systems in all present and likely future classes of airspace.
{"title":"Advances in low-altitude airspace management for uncrewed aircraft and advanced air mobility","authors":"Nichakorn Pongsakornsathien , Nour El-Din Safwat , Yibing Xie , Alessandro Gardi , Roberto Sabatini","doi":"10.1016/j.paerosci.2025.101085","DOIUrl":"10.1016/j.paerosci.2025.101085","url":null,"abstract":"<div><div>Contemporary trends in Uncrewed Aircraft Systems Traffic Management (UTM) and Advanced Air Mobility (AAM) are redefining low-altitude airspace operations, particularly in urban and suburban settings where traditional airspace management approaches are inadequate to support the predicted air transport demands. To address these challenges, the development of an integrated Low-Altitude Airspace Management (LAAM) framework is seen as an essential next step, requiring new flight systems and infrastructure tailored to the distinct challenges of these environments. Cyber technologies, including automation and Artificial Intelligence (AI), play a crucial role in LAAM by integrating data from Communication, Navigation, and Surveillance (CNS) systems to support real-time and automated decision-making for separation assurance and flow management. While human operators and social interactions retain a very important role in LAAM collaborative decision-making processes, the reliance on automation is expected to continue growing, driven by the need to effectively manage the challenges arising from the increasing number and diversity of highly automated and uncrewed aircraft. Regulatory frameworks must adapt to accommodate the unique characteristics of AAM operations, ensuring the adequacy of safety standards and airspace regulations. In particular, airspace design is bound to evolve to accommodate Vertical/Short Take-off and Landing (V/STOL) aircraft’s distinct capabilities and requirements. The deployment of AI in safety-critical systems will require rigorous verification, validation, and certification processes to ensure reliability and trustworthiness. To address these complex and interrelated challenges, a harmonized LAAM Concept of Operations (CONOPS) is needed, which should encapsulate both UTM and emerging AAM requirements, while clearly specifying the role of human operators for various levels of automation. Additionally, new system functionalities should be developed to enhance human-machine teaming by focussing on CNS performance-based airspace modeling and dynamic airspace management. Based on these premises, an integrated approach to Multi-Domain Traffic Management (MDTM) is emerging, with promising future perspectives for the safe, efficient and sustainable operation of highly automated and autonomous flight systems in all present and likely future classes of airspace.</div></div>","PeriodicalId":54553,"journal":{"name":"Progress in Aerospace Sciences","volume":"154 ","pages":"Article 101085"},"PeriodicalIF":11.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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