Acta Astronautica最新文献

{"title":"DSMC analysis of Astrobotic’s Peregrine Mission-1: MON-25 leak and water outgassing","authors":"Stefano Boccelli ,&nbsp;Orenthal J. Tucker ,&nbsp;Michael J. Poston ,&nbsp;Parvathy Prem ,&nbsp;Tristram Warren ,&nbsp;Aleksandra J. Gawronska ,&nbsp;Simeon J. Barber ,&nbsp;William M. Farrell ,&nbsp;Barbara A. Cohen","doi":"10.1016/j.actaastro.2025.08.021","DOIUrl":"10.1016/j.actaastro.2025.08.021","url":null,"abstract":"<div><div>Astrobotic’s Peregrine Mission-1 spacecraft experienced a propulsion system anomaly that prevented the lander from reaching the Moon. During the mission, several instruments operated successfully in cis-lunar space. Among them, the Peregrine Ion Trap Mass Spectrometer (PITMS) measured both the presence of outgassing water and nitrogen oxides traceable to the MON-25 oxidizer. We performed Direct Simulation Monte Carlo (DSMC) studies of the oxidizer leak on Peregrine to characterize the gas diffusion from the leak to the instrument, mediated by inter-species collisions and gas–surface interaction. We conclude that the latter process was prevalent and that diffusion paths through Peregrine are necessary to explain the PITMS detections. Our DSMC study and estimation of Peregrine’s outgassing rate suggest that, at the early stage of the mission, the spacecraft released water at a rate comparable to the Space Shuttle and at a much larger rate than typical spacecraft during science operations. This provides useful information for planning future operations of science instruments on commercial missions.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 196-207"},"PeriodicalIF":3.4,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-term response of cerebrovascular and ocular hemodynamics from micro- to hyper-gravity: A multiscale mathematical analysis","authors":"Francesco Tripoli ,&nbsp;Luca Ridolfi ,&nbsp;Stefania Scarsoglio","doi":"10.1016/j.actaastro.2025.08.028","DOIUrl":"10.1016/j.actaastro.2025.08.028","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Exposure to micro- and hyper-gravity characterizes the spaceflight environment, leading to several short- to long-term physiological alterations. However, both acute and long-term cerebrovascular and ocular responses are still being investigated and far from being understood, with experimental data being fragmented and incongruent.&lt;/div&gt;&lt;div&gt;In this study, we aim to shed light on cerebro-ocular hemodynamics during short-term exposure to altered gravitational acceleration (from &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; to 3&lt;span&gt;&lt;math&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), by employing a multiscale 0D-1D model of the cardiovascular system. The modeling approach consists of a 1D representation of the arterial and coronary circulations, along with a 0D parametrization of the arteriolar, capillary, venous, cardiopulmonary, coronary, and cerebro-ocular circulations. The model is equipped with short-term regulation mechanisms (i.e., cerebral autoregulation, baroreceptors, and cardiopulmonary reflex) and includes the collapse of the neck veins.&lt;/div&gt;&lt;div&gt;After validating the model against experimental measurements of cerebral and ocular hemodynamic parameters, our findings indicate that micro-gravity leads to increased cerebral and ocular perfusion pressure (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, respectively), whereas beat-averaged values of cerebral blood flow (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) are near-constant due to cerebral autoregulation. However, pulsatile values of pressure and flow rate are increased, especially in the distal cerebral circulation. Additionally, the equilibrium between intracranial and intraocular pressure (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, respectively), which is thought to play an important role in the onset of Spaceflight Associated Neuro-Ocular Syndrome, is disrupted, resulting in reduced translaminar pressure (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;). Conversely, hyper-gravity induces significant orthostatic stress that results in a reduction of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. Consequently, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; abruptly drops at higher &lt;span&gt;&lt;math&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; values, together with hemodynamic pulsatility. In these conditions, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; decreases more than &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, leading to an increase in &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;.&lt;/div&gt;&lt;div&gt;Present results further underline the usefulness of numerical methods","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 159-173"},"PeriodicalIF":3.4,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mission extension of Hayabusa2 for planetary defense, small body flyby and rendezvous sciences","authors":"Yuichi Tsuda,&nbsp;Yuya Mimasu,&nbsp;Takanao Saiki,&nbsp;Satoru Nakazawa,&nbsp;Makoto Yoshikawa,&nbsp;Eri Tatsumi","doi":"10.1016/j.actaastro.2025.08.037","DOIUrl":"10.1016/j.actaastro.2025.08.037","url":null,"abstract":"<div><div>Hayabusa2, the second Japanese asteroid sample return mission, successfully returned to Earth on December 6, 2020 with primordial samples of the carbonaceous asteroid Ryugu. After releasing the sample return capsule toward Earth, the Hayabusa2 spacecraft commenced the new mission to two new asteroids by taking advantage of the remaining space asset that was fully healthy state with approximately half of the fuel remaining. This mission extension, named as “Hayabusa2#” or “Hayabusa2-SHARP” (<u>S</u>mall <u>H</u>azardous <u>A</u>steroid <u>R</u>econnaissance <u>P</u>robe), aims at visiting two asteroids, Torifune (formerly designated as 2001 CC21) to fly-by in 2026, and 1998 KY26 to rendezvous in 2031 to contribute to science and technology of the planetary defense, flyby science of a small body, and rendezvous science of a small fast-rotator suspected dark-comet. This paper describes the mission plan, technical challenges and ongoing development status of the Hayabusa2# mission.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 254-260"},"PeriodicalIF":3.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determining the best technique: Methods, challenges, and innovations of performing microgravity CPR","authors":"Amber Smowton ,&nbsp;Anitha Uthayasooriyan ,&nbsp;Esha Kamran ,&nbsp;Sara Terracciano ,&nbsp;Pankaj Bhavsar ,&nbsp;Thais Russomano","doi":"10.1016/j.actaastro.2025.08.022","DOIUrl":"10.1016/j.actaastro.2025.08.022","url":null,"abstract":"<div><h3>Background</h3><div>Space travel has always been one of humanity's grand visions. Though previously only selected astronauts could make this journey, commercial spaceflight has become a new frontier for exploration. Travelling in microgravity has many effects on the human body; the risk of unlikely but potentially fatal conditions, such as cardiac arrest, increases. On Earth, as in space, cardiac arrest demands immediate intervention through CPR. However, microgravity causes weightlessness which necessitates alternative techniques. CPR is governed by International CPR Guidelines (2020/21), which state that external chest compressions (ECC) must reach a depth of 50–60 mm, at a rate of 100–120 compressions per minute (CPM). This narrative review aims to investigate which microgravity CPR (mCPR) method is most effective according to these guidelines, as well as their challenges and innovations.</div></div><div><h3>Methods</h3><div>A literature search was conducted; initially 240 papers were found from the following databases: OVID (MEDLINE and EMBASE), SCOPUS, Web of Science, NASA Technical Reports Server, and Imperial Library Search was used for other records. Duplicates were removed and each reviewer assessed the papers for relevance. 25 studies were found, dating from 1990 to 2022, with 10 of these being primary research.</div></div><div><h3>Results</h3><div>The seven main techniques for conducting mCPR are the standard side position (SSP), waist straddle (WS), reverse bear-hug (RBH), handstand (HS), Evetts-Russomano (ER), Schmitz-Hinkelbein (SHB) and Cologne method (CM). Other methods include using various assistive devices, including the Stryker LUCAS 3, which had the greatest ECC depth of any method (49.9 ± 0.7 mm). Of the non-device methods, the HS was found to have the largest mean ECC depth (43.7 mm) and had the greatest mean ECC rate (105 CPM). ER achieved a mean ECC depth of 43.3 mm and mean ECC rate of 100.3 CPM. This is slightly less than that of HS, however based on practicality, ER may be easier to perform.</div></div><div><h3>Discussion</h3><div>CPR is difficult to carry out to acceptable standards (according to International 2020/2021 guidelines) even on Earth, where gravity allows body weight to provide the force needed for ECC. Despite a device providing the most effective chest compressions, it may not be feasible to bring to space due to size and weight constraints. Otherwise, the HS and ER are generally accepted as the most effective and least fatiguing mCPR methods. However, further research is required, as these results are based on limited data.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 361-370"},"PeriodicalIF":3.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reference orbit construction for tetrahedral formation on elliptical orbit","authors":"Sergei Shestakov","doi":"10.1016/j.actaastro.2025.08.019","DOIUrl":"10.1016/j.actaastro.2025.08.019","url":null,"abstract":"<div><div>The work proposes a method for designing reference motion trajectories for a tetrahedral satellite formation operating on a highly elliptical orbit. The main goal is to define such initial conditions of satellite motion that allow the tetrahedron to preserve its volume. The algebraic technique is presented that guarantees the conservation of the volume in linear motion approximation. The presented technique is also applied to maintain a shape of the formation.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 151-158"},"PeriodicalIF":3.4,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerobraking: Review of the state of the art and required developments","authors":"Maximilien Berthet","doi":"10.1016/j.actaastro.2025.08.015","DOIUrl":"10.1016/j.actaastro.2025.08.015","url":null,"abstract":"<div><div>Aerobraking is the process of circularising an eccentric spacecraft orbit using aerodynamic drag in a planetary atmosphere, most commonly for interplanetary mission applications. Since its first in-space demonstration in 1991, aerobraking has been successfully performed in a total of eight missions, at Earth, Venus, and Mars. Despite this promising track record, aerobraking has arguably not yet reached its full potential. For instance, the most recent mission with aerobraking was launched around a decade ago, and the technique has only been used by relatively large spacecraft weighing over 100 kg. Against this backdrop, this article performs a comprehensive review of the state of the art in preparation for the next generation of missions with aerobraking. First, the eight missions that have already performed aerobraking are summarised. Important data on the aerobraking performance is extracted. Second, opportunities opened by aerobraking for interplanetary transportation and science are evaluated. Significant propellant savings can be achieved compared to a conventional propulsive manoeuvre, reducing launch mass and cost. Aerobraking also offers insights into atmospheric science and rarefied gas dynamics. Third, however, important challenges remain to make aerobraking easier. Resource-intensive ground-based operations and atmospheric uncertainty are two notable ones. These are examined in detail and potential ways forward are reviewed, including autonomous aerobraking. Fourth, a future outlook is provided, including on potential synergies between aerobraking, small satellites, and space sails. It is hoped this paper will help to inject new wind into aerobraking research and applications.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 107-126"},"PeriodicalIF":3.4,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine-tuning a narrowband SETI signal processing pipeline","authors":"Kenneth M. Houston","doi":"10.1016/j.actaastro.2025.08.024","DOIUrl":"10.1016/j.actaastro.2025.08.024","url":null,"abstract":"<div><div>A narrowband radio frequency Search for Extraterrestrial Intelligence (SETI) presumes a long-duration (<span><math><mo>≈</mo></math></span>minutes), low bandwidth (<span><math><mrow><mo>≈</mo><mi>Hz</mi></mrow></math></span>) beacon or incidental transmitted signal that would be unlikely to occur in the natural world: a technosignature. A constant-frequency signal at the transmitter will drift in frequency on reception due to relative accelerations between the transmitter and receiver. Drift rates will be proportional to center frequency, e.g. up to <span><math><mo>±</mo></math></span>0.44 Hz/s/GHz (Li et al. 2023). The typical signal processing pipeline involves creation of spectrograms over a wide bandwidth (up to 1 GHz) with Hz-level frequency resolution, followed by De-Doppler integration, which integrates energy over linearly-drifting tracks in the time–frequency plane.</div><div>Search capabilities have greatly expanded over recent years to include interferometric radio telescopes and aperture arrays (MeerKAT, VLA, MWA), commensal observing, and GPU-augmented server racks. However, the key detection algorithms in the dominant SETI search code used by Breakthrough Listen (BL) researchers have not been updated in spite of many works describing shortcomings. While updates by BL are in progress, it is important to review key design issues to be sure they are addressed.</div><div>In this paper, improvements to the BL algorithms and their implementation are discussed. Topics include: (1) an improved spectrogram normalization method for accurate threshold determination, (2) reducing spectrogram compression to avoid sensitivity losses, and (3) comparison of the commonly-used Taylor De-Doppler method to the fastDD algorithm (Houston, 2023). Reduced SNR losses on the order of 4–8 dB should be possible at high drift rates by optimizing averaging parameters. In addition, potential future post-detection pipeline enhancements are described, such as radio-frequency interference rejection, direction-of-arrival estimation, and waveform extraction.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 127-140"},"PeriodicalIF":3.4,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leading the crew to Mars: Evidence from NASA HERA analog crews","authors":"Alina Lungeanu ,&nbsp;Leslie A. DeChurch ,&nbsp;Megan A. Chan ,&nbsp;Noshir S. Contractor","doi":"10.1016/j.actaastro.2025.08.030","DOIUrl":"10.1016/j.actaastro.2025.08.030","url":null,"abstract":"<div><div>Space agencies across the world have started to prepare for the next bold human endeavor, a mission to Mars. One of its significant challenges is organizational: supporting successful collaboration within a small team that will live and work together under extreme conditions for an extended period of time. Team leadership will be pivotal to mission success, providing direction, enabling creative thinking, minimizing conflicts, negotiating across expertise domains, and maintaining high levels of motivation throughout the mission. Whereas past space missions have largely taken the view that leadership must be hierarchical, given the autonomy of deep space exploration, these missions may benefit from shared leadership among the crew. The international nature of the mission, collaboration among peers, the combination of crew members with very different areas of expertise by design, and the unprecedented autonomy given to the crew all suggest that space crews may benefit from shared, as opposed to hierarchical leadership networks. In order to understand the role of leadership networks in deep space exploration, this study investigated crew leadership in 13 crews participating in HERA campaigns between 2016 and 2020. These crews exhibited substantial variation in leadership, at times adopting shared, hierarchical, and fragmented leadership. The designated commander was the most likely to be perceived as a leader as compared to the other crew members, though in many cases the commander shared leadership with other crew members. Each crew exhibited, at some point in the mission, both a shared and a hierarchical structure. Five crews exhibited a period when leadership was fragmented–when no single crew member was recognized as the leader by the other crew members. There was an interesting association between leadership structure and mission timing such that fragmentation was most likely to occur during the fourth quarter, and shared leadership was most likely to characterize the crew on the first and last day, as compared to any day in between. Lastly, shared leadership was most prevalent in Campaign 5, which removed the interior walls from inside the habitat, increasing interaction among crew members.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 141-150"},"PeriodicalIF":3.4,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predetermined-time super-twisting prescribed performance control for morphing aircraft under external disturbances","authors":"Naying Li ,&nbsp;Yibo Ding ,&nbsp;Xuebao Ma ,&nbsp;Tianchen Zhang ,&nbsp;Jin Cheng ,&nbsp;Xiaokui Yue","doi":"10.1016/j.actaastro.2025.08.031","DOIUrl":"10.1016/j.actaastro.2025.08.031","url":null,"abstract":"<div><div>High-speed morphing aircraft is significantly more complex than conventional aircraft due to its unique structure, dynamic, and environmental characteristic, characterized by strong coupling and nonlinear dynamics. Traditional controllers are unable to achieve high control quality under severe external disturbances and parameter perturbations, nor can they meet the requirements for fast response, strong robustness, and high-precision control under multiple operational constraints. To address these challenges, this paper firstly establishes a comprehensive kinematic and dynamic model of the morphing aircraft. The dynamic model is conducted using the Newton-Euler vector mechanics approach, which considers the translational and rotational motions of both the fuselage and wings. The derived multi-rigid body dynamical equations analyze aerodynamic forces, gravitational forces, thrust, and control torques, while effectively solving the coupling effects between the fuselage and wing motions. Subsequently, a novel predetermined-time prescribed performance controller is proposed in this paper, which effectively limits the transient and steady-state performance of the morphing aircraft. The proposed controller transforms constrained tracking errors into unconstrained ones, ensuring that the original tracking error satisfies prescribed bounds. Building on this framework, a super-twisting algorithm and double power reaching law are introduced to accelerate convergence and suppress system chattering. Finally, simulation results demonstrate that the controller achieves stable control of high-speed morphing aircraft during the morphing process, effectively satisfying flight constraints in complex and dynamic environments. In addition, practical implementation issues of the proposed controller have been considered, such as sensor noise, actuator delays, and computational feasibility, supporting its feasibility in real-time flight scenarios.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 261-274"},"PeriodicalIF":3.4,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144906973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suppression of combustion instability in a scramjet engine using unsteady fuel injection","authors":"Guangming Du ,&nbsp;Erda Chen ,&nbsp;Changchun Yan ,&nbsp;Ye Tian ,&nbsp;Jialing Le","doi":"10.1016/j.actaastro.2025.08.033","DOIUrl":"10.1016/j.actaastro.2025.08.033","url":null,"abstract":"<div><div>Combustion instability remains a critical barrier to the reliable operation of scramjet engines, especially under high-speed, high-enthalpy conditions. This study investigates the use of unsteady fuel injection as a control strategy to suppress such instabilities in a kerosene-fueled scramjet combustor. Experiments were conducted in a direct-connect supersonic combustion facility at Mach 3.0, with fuel injection modulated at frequencies (171, 216, and 260 Hz) and equivalence ratios of 0.5 and 0.6. High-speed chemiluminescence imaging and pressure transducer measurements were employed to analyze flame dynamics and pressure oscillations. Results demonstrate that unsteady injection at 216 Hz, combined with an equivalence ratio of 0.6, induces a transition from an unstable mode to a stable ram mode, significantly suppressing pressure fluctuations and enhancing combustion intensity. In contrast, unsteady injection at lower equivalence ratios or non-optimal frequencies failed to mitigate instabilities and, in some cases, exacerbated them. To interpret these findings, a reduced-order model (ROM) was developed based on dynamic coupling and time-delay effects between the fuel supply and combustion zones. The ROM qualitatively predicts system stability by evaluating eigenvalues derived from experimental conditions and shows agreement with observed instability trends.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":"237 ","pages":"Pages 12-22"},"PeriodicalIF":3.4,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}