Acta Astronautica最新文献

{"title":"Micro-explosion-induced combustion and agglomeration characteristics in composite propellants with fluorinated graphene","authors":"","doi":"10.1016/j.actaastro.2024.09.050","DOIUrl":"10.1016/j.actaastro.2024.09.050","url":null,"abstract":"<div><div>The potential of the Al-F reaction in suppressing agglomeration during propellant combustion and enhancing combustion performance is investigated by introducing fluorinated graphene as a fluorinated oxidizer. Comparative analyses of ignition combustion and agglomeration behaviors are conducted on novel composite powders and propellant samples modified with varying contents of fluorinated graphene using laser and hot wire ignition visualization systems. Characterizing parameters such as characteristic spectra, flame grayscale, ignition delay time, combustion duration, and burning rate are measured during combustion at different pressures. Additionally, agglomerated particles are collected via quenching techniques under 7 MPa pressure to explore the influence mechanism of fluorinated graphene on agglomeration near the burning surface, and a comprehensive influence mechanism is proposed. Results indicate that fluorinated graphene promotes ammonium perchlorate decomposition, accelerates oxidizing gas release, and enhances thermal conduction at the burning surface. The reaction between Al and F decreases the formation of intermediates (AlO and Al₂O), while the interaction of F with Al and Al₂O₃ effectively inhibits the clustering of Al particles, replacing conventional oxidation reactions and resulting in a unique micro-explosion jetting phenomenon. The introduction of 15 % fluorinated graphene concentrates most product particles around 10 μm, enhancing energy release during combustion. Overall, this composite powder containing fluorinated graphene effectively improves the combustion performance of aluminum-containing composite propellants, inhibiting Al particle agglomeration and potentially reducing specific impulse loss in solid rocket motors.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314733","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":"Experimental study on the suppression of inlet blockage in rotating detonation combustor by porous-wall","authors":"","doi":"10.1016/j.actaastro.2024.09.030","DOIUrl":"10.1016/j.actaastro.2024.09.030","url":null,"abstract":"<div><div>The rotating detonation combustor (RDC) is renowned for its ability to provide substantial pressure gains. Nonetheless, during the stable operation of the RDC, the high-pressure rotating detonation wave (RDW) at the combustor inlet induces an increase in upstream chamber pressure, ultimately compromising engine stability and performance. To fully harness the performance advantages of the turbine-based continuous rotating detonation engine (TBCRDE) while maintaining engine stability, a porous-wall RDC has been developed to alleviate intake blockage and mitigate upstream chamber pressure rise. The operating modes, pressure rise characteristics, and performance parameters of both the porous-wall RDC and the reference configuration were systematically evaluated across varying air flow rates and nozzle designs. This analysis concentrated on the operational characteristics of the porous-wall RDC and its mechanisms for suppressing upstream chamber pressure rise. The findings reveal that the porous-wall RDC significantly extends the stable operating range and effectively reduces upstream chamber pressure rise by minimizing intake blockage. Specifically, the stable operating range is enhanced by 50 % at an outlet area ratio of 0.33, with stable rotating detonation combustion achieved at an outlet area ratio of 0.25. At an air flow rate of 1 kg/s and an outlet area ratio of 0.33, the chamber pressure rise is optimally suppressed, demonstrating a maximum reduction of approximately 16.4 %. The total pressure recovery coefficient of the combustor was analyzed, taking into account both intake loss and combustor pressure gain capabilities, and the propulsion performance of the two configurations was compared. The porous-wall RDC effectively reduces intake loss while slightly diminishing combustor pressure gain capability, resulting in a marginal increase in the total pressure recovery coefficient. Although this leads to a slight reduction in propulsion performance during chamber pressure rise suppression, the overall engine matching environment benefits from enhanced matching stability. Consequently, other engine components experience a reduced performance decline. Therefore, the implementation of a porous-wall structure is anticipated to improve the overall propulsion performance of the engine.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311950","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":"Sequential convex programming without penalty function for reentry trajectory optimization problem","authors":"","doi":"10.1016/j.actaastro.2024.08.057","DOIUrl":"10.1016/j.actaastro.2024.08.057","url":null,"abstract":"<div><p>Sequential convex programming (SCP) has been extensively utilized in reentry trajectory optimization due to its high computational efficiency. However, the current SCP approaches primarily rely on penalty function, where the selection of the penalty function weight presents a significant challenge. In this paper, an improved trust region shrinking SCP algorithm is proposed that separates the treatment of the objective function and constraint violation without the need for selecting penalty function weight and introduction of slack variables. Firstly, from the perspective of multi-objective optimization, the filter and acceptance condition are introduced to ensure that the proposed algorithm converges to feasible solutions and then to the optimal solution based on switching condition and sufficient condition. Then an effective feasibility restoration phase is proposed to address infeasibility of subproblems without introducing slack variables, while ensuring the robustness of the proposed algorithm. Additionally, a theoretical analysis is provided to guarantee the convergence of the algorithm. Finally, simulations are conducted to verify that the proposed algorithm demonstrates a 69.54% improvement in average solution time and stronger robustness compared to basic trust region shrinking SCP algorithm. Simultaneously, the proposed algorithm also demonstrates an advantage in solving speed compared to a particular advanced penalty function-based SCP algorithm.</p></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272265","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":"Mathematical modeling of nonequilibrium combustion processes in a liquid rocket engine","authors":"","doi":"10.1016/j.actaastro.2024.09.035","DOIUrl":"10.1016/j.actaastro.2024.09.035","url":null,"abstract":"<div><div>The key problems of safety for Space missions begin with safety, reliability and effectiveness of rocket engines of different types used at different launch stages and orbit corrections. Today, the possibilities for improving chemical rocket engines of traditional types are almost completely exhausted and are limited to minor improvements in energy-mass characteristics. A qualitative leap in the development of engine building can only be achieved through the development and implementation of new types of engines. As unburned fuel in the combustion chamber is a loss of thrust for the engine, the study of droplet combustion and evaporation, in particular, the droplet lifetime, is of fundamental importance in the creation of combustion chambers using atomized liquid fuel in their operation.</div><div>In this paper a quasi-stationary model, which describes the evaporation of a single droplet in a gaseous atmosphere, is presented. Since in the numerical implementation the mass flow from the liquid phase to the gas and the heat flux from the droplet to the gas are calculated based on the Peclet number and the droplet surface temperature obtained from the quasi-stationary problem, approximation formulas for these parameters are developed in this paper. As an example, the problems of evaporation of a liquid oxygen droplet in an atmosphere of gaseous hydrogen and a droplet of liquid n-decane in an atmosphere of gaseous oxygen are considered. Formulas for calculation of mass flow and heat flux from liquid phase to gas based on the solution of the droplet evaporation problem are presented. Estimates of droplets lifetime in engine are provided based on developed droplet evaporation models.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311683","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":"Optimization of MMX relative quasi-satellite transfer trajectories using primer vector theory","authors":"","doi":"10.1016/j.actaastro.2024.09.031","DOIUrl":"10.1016/j.actaastro.2024.09.031","url":null,"abstract":"<div><p>Quasi-satellite orbits (QSO) are stable retrograde parking orbits around Phobos that are currently being considered for JAXA’s upcoming robotic sample return mission Maritan Moons Exploration (MMX). During the proximity operations of MMX, the spacecraft inserted in a high altitude QSO will gradually descend to lower altitude QSOs with suitable transfer and station-keeping techniques between different relative QSOs. Preliminary analysis of two-impulsive planar transfers between relative retrograde orbits utilizing the bifurcated QSOs families is studied to estimate the <span><math><mrow><mi>Δ</mi><mi>V</mi></mrow></math></span> costs and time of flights of the transfers. In this paper, differently from previous works, we utilize the initial guesses found through the preliminary results that provide two-impulsive transfer <span><math><mrow><mi>Δ</mi><mi>V</mi></mrow></math></span> execution points and optimize the transfers between relative QSOs around Phobos. Primer vector theory is applied to investigate the primer vector of the MMX transfer trajectories to evaluate whether intermediate maneuver or initial/final coasting times along the trajectories can minimize the total <span><math><mrow><mi>Δ</mi><mi>V</mi></mrow></math></span> cost between the transfers. Based on the primer vector analysis of the impulse transfer trajectories, it is found that departing and arriving at the same periphobian sides with an additional mid-course impulse results in the optimal impulse solution.</p></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0094576524005332/pdfft?md5=6f13c7e7d596164262927d53ec0f2069&pid=1-s2.0-S0094576524005332-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the observed time evolution of cosmic rays in a new time domain","authors":"","doi":"10.1016/j.actaastro.2024.09.034","DOIUrl":"10.1016/j.actaastro.2024.09.034","url":null,"abstract":"<div><p>Since the 1990's, it has been recognized that the full explanation of cosmic rays (CR) and their spectrum may require some new physics. The debate on the origin of CR has led to the conclusion that while most CR come from supernova explosions in the Galaxy, CR with very high energies are likely of extragalactic origin. However, a response to several open questions, still unanswered, concerning CR above 10¹³ eV is required. We herewith study the temporal evolution of the observational CR using data collected by several stations of the ground-based network. The obtained result states that the power spectral density of the CR temporal evolution, especially with a frequency less than 0.1 Hz, exhibits the Kolmogorov-Obukhov 5/3 law that exhibits the energy spectrum of many geophysical quantities. Any small difference found from the 5/3 exponent can be attributed to intermittency corrections and the stations' characteristics. Moreover, natural time analysis applied to the CR time series showed the critical role of the quasi-biennial oscillation to the entropy maximization which occurs following the 5/3 Kolmogorov-Obukhov power law. These findings can be used to more reliably predict extreme CR events that could have an impact even at the molecular level.</p></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272281","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":"A search for Planet Nine with small spacecraft: Three-body, post-Newtonian, non-gravitational, planetary and Kuiper Belt effects","authors":"","doi":"10.1016/j.actaastro.2024.09.020","DOIUrl":"10.1016/j.actaastro.2024.09.020","url":null,"abstract":"<div><p>A hypothetical gravitating body in the outer Solar System, the so-called Planet Nine, was proposed to explain the unexpected clustering of the Kuiper Belt Objects. As it has not been observed via telescopes, it was conjectured to be a primordial black hole (of the size of a quince) that could be gravitationally detected by laser-launching or solar sailing many small spacecraft. Here, we study various aspects that will affect such a search for Planet Nine. Our basic observable is the angular displacement in the trajectory of a small spacecraft which will be mainly affected by the gravity of Planet Nine, augmented with several other 3-body, non-gravitational, post-Newtonian, planetary and Kuiper Belt effects. First, we calculate the effect of the Sun in the framework of the circular restricted three-body problem of the Sun–Planet Nine-spacecraft for the two particular initial conditions. Then, we study the effects of Kuiper Belt and outer planets, namely Jupiter, Saturn, Uranus, Neptune, as well as non-gravitational perturbations such as magnetic and drag forces exerted by the interstellar medium; and the solar radiation pressure. In addition, we investigate the post-Newtonian general relativistic effects such as the frame-dragging, Schwarzschild effect, and geodetic precession on the spacecraft trajectory. We show that the leading order angular displacement is due to the solar radiation pressure for the lower spacecraft velocities, and the drag force for the higher spacecraft velocities. Among the general relativistic effects, the frame-dragging has the smallest effect; and the Schwarzschild effect due to Sun has the largest effect. However, none of the general relativistic effects produces a meaningful contribution to the detection.</p></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272282","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":"Space tether research at the University of Stuttgart","authors":"","doi":"10.1016/j.actaastro.2024.09.036","DOIUrl":"10.1016/j.actaastro.2024.09.036","url":null,"abstract":"<div><div>Space tether research activities at the University date back to the 1990s. First research projects investigated tether-assisted re-entry of payload return capsules from space stations. Tether research was resumed in 2015 focusing on the application of tethered planetary exploration rovers, based on the micro-rover Nanokhod. This includes robust, highly-integrated and miniaturised tethers and tether spooling systems, which are specifically adapted to the challenging lunar environmental and dust conditions. For this, several prototypes were developed and tested and a tether-dust testing facility was setup. In addition, developments have been made in the tether detection by creating a simulation framework, tracking algorithms and low-fidelity test bench for the verification of the algorithms. Based on the experience of the planetary tether applications, the research at the University of Stuttgart was expanded to Tethered Satellite Systems in 2022, utilising the tether spooling technology. In-depth studies on tethered CubeSat missions were developed together with students as part of educational activities, including tethered rendezvous capabilities and electrodynamic tether operation. In addition, breadboard models of optical detection and tracking payloads were developed for tracking a CubeSat sized object at full tether deployment of 100m. Additional subsystem development is currently in progress, consolidating the results of the mission studies, as well as dynamic analyses and simulations of the tethered satellite system. Concurrently, a third tether application research area was established, looking into studies for creating tether-based spaceflight infrastructure for lunar exploration missions. A concept study of a Momentum Exchange Tether system to transfer large payloads from Low Earth Orbit to a lunar transfer orbit was conducted and feasible tether system configurations were drafted. Various technological and operational challenges were identified and are now the focus of ongoing Momentum Exchange Tether research at the University of Stuttgart.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamic analysis of the hydrocarbon-fuelled air-turborocket engine with complete-combustion gas generator","authors":"","doi":"10.1016/j.actaastro.2024.09.037","DOIUrl":"10.1016/j.actaastro.2024.09.037","url":null,"abstract":"<div><p>The Air-Turborocket (ATR) engine can work at Mach 0<span><math><mo>∼</mo></math></span>4 or even higher speed, which is considered one of the best low Mach number propulsion systems for reusable hypersonic vehicles. However, because the hydrocarbon-fuelled ATR engine uses a fuel-rich gas generator, the combustion product contains a large amount of C(gr) that can cause coking in the turbine in a few minutes. To solve this problem, an ATR engine cycle with a complete-combustion gas generator (ATR-CCGG) was proposed. The performance of this cycle has been analysed through the thermodynamic model, and the influence factors and the sensitivity study of the cycle performance have been investigated. The results show that when the equivalence ratio is 1, the cycle can get more than 700 s of specific impulse and 1000 m/s of specific thrust at supersonic speed. Although the performance at subsonic speed is lower than that of the LOX/Kerosene ATR engine, the gas generator without C(gr) can ensure the engine to work for hours without coking in the turbine at different Mach numbers, which can be used in reusable hypersonic vehicles or single-stage-to-orbit missions.</p></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272260","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":"Identification of parameters for tethered satellite system to emulate net-captured debris towing","authors":"","doi":"10.1016/j.actaastro.2024.09.022","DOIUrl":"10.1016/j.actaastro.2024.09.022","url":null,"abstract":"<div><div>Net-based debris capture systems have a high potential for success in Active Debris Removal (ADR) missions. Simulation is an important tool in the analysis of the dynamics of nets, before experiments and actual missions are put in place. However, due to the large number of degrees of freedom required to model the dynamics of a net, in addition to nonlinearities, high-fidelity net-based ADR simulations are typically very computationally costly. This work focuses on the post-capture phase of a net-based ADR mission and aims to identify parameters of a lower-order model of the towed debris system such that it best matches the high-fidelity simulations with a full net. A model of a tethered satellite system with four sub-tethers is developed, and two optimization problems are formulated – minimizing the difference in dynamical quantities of interest – to perform the parameter identification task. The proposed system identification framework is first validated on a benchmark sub-tether model with known parameters, and then employed to minimize the difference in dynamics between the full-net and sub-tether debris towing simulations. The performances of the optimized solutions obtained from two proposed cost functions are compared both qualitatively and quantitatively. Overall, the proposed lower-order modeling and parameter identification framework demonstrate satisfactory performance in approximating the dynamics of the high-fidelity system.</div></div>","PeriodicalId":44971,"journal":{"name":"Acta Astronautica","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326491","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}