Aerotecnica Missili & Spazio最新文献_第9页

Cassini Bistatic Radar Experiments: Preliminary Results on Titan’s Polar Regions 卡西尼双基地雷达实验：泰坦极地的初步结果

Aerotecnica Missili & Spazio Pub Date : 2022-09-10 DOI: 10.1007/s42496-022-00135-4

Giancorrado Brighi

{"title":"Cassini Bistatic Radar Experiments: Preliminary Results on Titan’s Polar Regions","authors":"Giancorrado Brighi","doi":"10.1007/s42496-022-00135-4","DOIUrl":"10.1007/s42496-022-00135-4","url":null,"abstract":"<div><p>In bistatic radar observations, reflected echoes from the surface of a target planet can be analyzed to infer its surface statistics and near-surface constituents. In this work, a preliminary inspection of two X-band bistatic radar observations gathered by the Cassini spacecraft about Titan’s polar regions is presented. Profiles of relative dielectric constant and root-mean-square (rms) surface slope are provided as outputs of the analysis, discussed, and compared with the present knowledge of Titan geomorphology. For the assessment of the rms slope, proportional to the spectral broadening of reflected echoes, a basic fitting procedure was applied to the received spectra using a Gaussian template, to later evaluate the full-width half-maximum of the fitting curve. The dielectric constant was computed from the power ratio between orthogonally circularly polarized components of signal reflections from Titan. Dielectric constant estimates are, on average, consistent with the expected materials covering the dry surfaces of the planet, while slightly low values were found over the seas. The rms slopes are generally low compared to past bistatic observations of other targets. Titan’s north polar seas are revealed to feature an unprecedented smoothness, with 0.01<span>(^circ)</span> of slope as an upper bound. Similar values were inferred for isolated spots in the southern pole, hinting at the possible presence of basins filled with liquid hydrocarbons. The main issues with the analysis are emphasized throughout the document, and some ideas for future work are presented in the conclusions.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"102 1","pages":"59 - 76"},"PeriodicalIF":0.0,"publicationDate":"2022-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00135-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50470475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

YORP Effect on Long-Term Rotational Dynamics of Debris in GEO YORP效应对地球同步轨道碎片长期旋转动力学的影响

Aerotecnica Missili & Spazio Pub Date : 2022-09-03 DOI: 10.1007/s42496-022-00134-5

Francesco Cuomo

{"title":"YORP Effect on Long-Term Rotational Dynamics of Debris in GEO","authors":"Francesco Cuomo","doi":"10.1007/s42496-022-00134-5","DOIUrl":"10.1007/s42496-022-00134-5","url":null,"abstract":"<div><p>The Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect describes the torque induced on space objects produced by solar radiation and thermal re-emission. Previous analyses have demonstrated its influence on long-term rotational dynamics of space debris objects in Geostationary Orbit (GEO), where YORP becomes predominant with respect to other external perturbations (e.g., atmospheric drag, gravity gradient, eddy current torque), leading to a wide variety of possible behaviors. The capability of forecasting time windows of slow uniform rotation, if any, would bring significant advantages in operations of Active Debris Removal and on-orbit servicing, especially in the detumbling phase. Also, a non-negligible impact of the End-of-Life configuration, in terms of movable surfaces orientation and center of mass location, could lead to guidelines for future satellites to be easier targets in the disposal phase. In this work, a previously derived semi-analytical tumbling-averaged YORP rotational dynamics model is leveraged. Exploiting an averaged model, computational time is strongly reduced while maintaining sufficient accuracy compared to propagation of Euler’s equations of motion. First, a satellite of the Geostationary Operational Environmental Satellite (GOES) family is analyzed and compared to previous studies to verify the correct implementation of the model. A wider analysis is performed on simple geometric models, such as a box-wing satellite, a 3U CubeSat, and a rocket body. The impact of object size, surface optical properties, and center of mass position on long-term rotational behavior is investigated, providing a general insight into these phenomena with a possible future application to existing objects in GEO.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"102 1","pages":"29 - 43"},"PeriodicalIF":0.0,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00134-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50446886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

3D Printing Techniques for Paraffin-Based Fuel Grains 石蜡基燃料颗粒的3D打印技术

Aerotecnica Missili & Spazio Pub Date : 2022-09-01 DOI: 10.1007/s42496-022-00126-5

Riccardo Gelain, Artur Elias De Morais Bertoldi, Adrien Hauw, Patrick Hendrick

{"title":"3D Printing Techniques for Paraffin-Based Fuel Grains","authors":"Riccardo Gelain, Artur Elias De Morais Bertoldi, Adrien Hauw, Patrick Hendrick","doi":"10.1007/s42496-022-00126-5","DOIUrl":"10.1007/s42496-022-00126-5","url":null,"abstract":"<div><p>Hybrid rocket propulsion systems have proved to be a suitable option for some specific applications in the space transportation domain such as in launch vehicle upper stages, orbit transfer spacecrafts, decelerator engines for re-entry capsules, and small satellites launchers. Part of the renewed interest in hybrid rocket propulsion is due mainly to the safety aspects, cost reduction, and the use of paraffin-based fuel that impacts positively in terms of the solid fuel regression rate. However, paraffin solid fuel grains have poor structural characteristics and sometimes low performance due to the fuel internal ballistics behaviour. More recently, various studies have been carried out to overcome these drawbacks of paraffin-based fuels, such as the addition of energetic nano-sized metallic powder and 3D printing techniques. This study presents a review of the principal concepts of 3D printing processes and extrusion techniques that can be suitable for paraffin grains manufacturing and the conceptual design of a prototype for a 3D printer system under development at the Aero-Thermo-Mechanics Department of Université Libre de Bruxelles.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"101 3","pages":"257 - 266"},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00126-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50001499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Challenges and Opportunities of Green Propellants and Electric Pump Feeding for Future European Kick Stages 绿色推进剂和电动泵给料对未来欧洲踢球阶段的挑战和机遇

Aerotecnica Missili & Spazio Pub Date : 2022-08-23 DOI: 10.1007/s42496-022-00133-6

L. Ordonez Valles, L. Blondel Canepari, U. Apel, M. Tajmar, A. Pasini

引用次数: 2

Explicit Near-Optimal Guidance and Pulse-Modulated Control for Lunar Descent and Touchdown 月球下降和着陆的显式近最优制导和脉冲调制控制

Aerotecnica Missili & Spazio Pub Date : 2022-08-13 DOI: 10.1007/s42496-022-00128-3

M. Pontani, F. Celani, S. Carletta

{"title":"Explicit Near-Optimal Guidance and Pulse-Modulated Control for Lunar Descent and Touchdown","authors":"M. Pontani, F. Celani, S. Carletta","doi":"10.1007/s42496-022-00128-3","DOIUrl":"10.1007/s42496-022-00128-3","url":null,"abstract":"<div><p>This research considers the descent path of a space vehicle, from periselenium of its operational orbit to the lunar surface. The trajectory is split in two arcs: (a) approach, up to a specified altitude, and (b) terminal descent and soft touchdown. For phase (a), a new locally flat near-optimal guidance is used, which is based on iterative projection of the spacecraft position and velocity, and availability of closed-form expressions for the related costate variables. Attitude control is aimed at pursuing the desired spacecraft orientation, and uses an adaptive tracking scheme that compensates for the inertia uncertainties. Arc (b) is aimed at gaining the correct vertical alignment and low velocity at touchdown. For phase (b) a predictive bang-off-bang guidance algorithm is proposed that is capable of guaranteeing the desired final conditions, while providing the proper allocation of side jet ignitions. Actuation of side jets is implemented using pulse width modulation, in both phases. Monte Carlo simulations prove that the guidance and control architecture at hand drives the spacecraft toward safe touchdown, in the presence of non-nominal flight conditions.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"101 4","pages":"361 - 370"},"PeriodicalIF":0.0,"publicationDate":"2022-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00128-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50476437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Analysis of an Acoustic Monopole Source in a Closed Cavity via CUF Finite Elements 封闭腔中声单极源的CUF有限元分析

Aerotecnica Missili & Spazio Pub Date : 2022-08-09 DOI: 10.1007/s42496-022-00129-2

M. C. Moruzzi, M. Cinefra, S. Bagassi

{"title":"Analysis of an Acoustic Monopole Source in a Closed Cavity via CUF Finite Elements","authors":"M. C. Moruzzi, M. Cinefra, S. Bagassi","doi":"10.1007/s42496-022-00129-2","DOIUrl":"10.1007/s42496-022-00129-2","url":null,"abstract":"<div><p>The noise generated by aircraft is an important issue, which affects the external environment and the passenger’s comfort. The researches about new acoustic solutions often lead to the exploitation of innovative materials, as visco-elastic panels or acoustic metamaterials, in order to rather obtain better acoustic properties than conventional materials, in particular at low frequency. Although, there is a lack of reliable tools able to describe the complex kinematic behaviour of these new materials at low frequency. A new strong formulation, the Carrera Unified Formulation (CUF) based on the Finite Element Method (FEM), enables a wide class of refined shell models, which is able to reproduce the frequency dependent dynamic response of complex multi-layered plates. This formulation, fully developed inside the MUL2 software, is applied to vibro-acoustic analyses too, so the need to integrate new sources and boundary conditions in the software, that are essential to model the acoustic problem. A simple and powerful source is the monopole: a pulsating sphere. This source can be a first try to model the complex sources that affect the noise inside the aircraft, as the engine or the internal sources. Moreover, monopoles are widely used to estimate the transmission loss. Hence, the reason for this work: the creation inside MUL2 of a monopole boundary condition and its validation, comparing the results with those of a well-known FEM based commercial software for vibro-acoustic analyses, Actran.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"101 4","pages":"371 - 385"},"PeriodicalIF":0.0,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00129-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50465049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sustainability Through Innovation: Advancing Space Access Capabilities from Europe (Special Issue) 通过创新实现可持续发展:提高欧洲的空间接入能力(特刊)

Aerotecnica Missili & Spazio Pub Date : 2022-08-09 DOI: 10.1007/s42496-022-00131-8

Christian Bach, Alessia Gloder, Vittorio Cipolla, Sergio De Rosa, Paolo Gasbarri, Aldo Frediani

引用次数: 0

AIDAA News #15 AIDAA新闻#15

Aerotecnica Missili & Spazio Pub Date : 2022-08-03 DOI: 10.1007/s42496-022-00130-9

Marco Petrolo

引用次数: 0

Aerodynamic Analysis of a Box Winglet: Viscous and Compressible Flow Predictions 箱形小翼的气动分析：粘性流和可压缩流预测

Aerotecnica Missili & Spazio Pub Date : 2022-07-23 DOI: 10.1007/s42496-022-00125-6

Lorenzo Russo, Ettore Saetta, Renato Tognaccini, Giulio Dacome, Luciano Demasi

引用次数: 1

Health Monitoring of Reuseable Rockets: Basics for Sensor Selection 可重复使用火箭的健康监测:传感器选择的基础

Aerotecnica Missili & Spazio Pub Date : 2022-07-11 DOI: 10.1007/s42496-022-00127-4

Andrea Vennitti, Tino Schmiel, Christian Bach, Martin Tajmar

{"title":"Health Monitoring of Reuseable Rockets: Basics for Sensor Selection","authors":"Andrea Vennitti, Tino Schmiel, Christian Bach, Martin Tajmar","doi":"10.1007/s42496-022-00127-4","DOIUrl":"10.1007/s42496-022-00127-4","url":null,"abstract":"<div><p>With regard to the space field, the number of the sensors has grown for a middle-sized spacecraft from more than 500 at the beginning of the twenty-first century [1] to several thousands for nowadays applications. Meanwhile, Reusable Launch Vehicles (RLVs) moved their steps from demonstrators to commercial working systems. As a result, Health Monitoring (HM) is conquered its own space in the field and sensors are the primary elements required for implementing a monitoring unit. The innovative concept of reusable rockets requires, from the point of view of HM implementation, not only the evaluation of the vehicle health status but also the prediction of the reusability of the individual subsystems w.r.t. the next launch cycle. Therefore, the goal of this work is divided in two parts. The former is to identify the most critical points for the development of reusable rockets, focusing on theoretical working conditions and analysis or failures. The latter is to discuss the sensing units useful for addressing the defined points, describing the possible innovative approaches for sensing the system conditions. Among them, piezoelectric units, fiber optics, imaging units, and conductive layers can be identified for enhancing the comprehension of the system working conditions.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"101 3","pages":"215 - 226"},"PeriodicalIF":0.0,"publicationDate":"2022-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-022-00127-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50020046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0