bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman spectroscopic measurements on San Carlos olivine up to 14 GPa and 800 K: Implications for thermodynamic properties
Authors: Liu Dan , Song Haipeng , Zhu Xi , Ye Yu , Smyth Joseph R. , Hu Yancheng , Wang Sha , Miao Yunfan , Liu Yungui
Published: October 2023

Olivine, the most abundant mineral in the upper mantle, plays a key role in controlling the thermodynamic properties in the Earth’s and planetary interiors, like the temperature distribution along the adiabatic geotherm. In this study, we conducted simultaneous high-pressure (P) and high-temperature (T) Raman measurements on a San Carlos olivine sample in an externally heated diamond-anvil cell (DAC). The intrinsic anharmonic parameters, ai, are calculated as functions of both pressure and temperature, and the isochoric (CV) and isobaric (CP) heat capacities are computed at various P-T conditions with the anharmonic correction. The harmonic heat capacities are CV = 807.7 J/kg/K and CP = 815.4 J/kg/K at ambient conditions, with anharmonic contribution of ΔC = 7.9 J/kg/K. Relative to the previous vibrational measurements conducted at high-P or high-T conditions, this simultaneous high-P-T experiment indicates that the anharmonic contribution to heat capacities is overestimated if the anharmonic parameters (ai) are treated as constants, as done previously. The pressure effect is marginal on the intrinsic anharmonic contribution to thermodynamic properties, whereas it has a much more significant effect on the external anharmonicity (thermal expansivity). The pressure dependence of CP (dCP/dP, in J/kg/K/GPa) increases from –3.14 at 300 K to –1.94 at 700 K, and then decreases smoothly to –5.03 at 1800 K. Combining the derived high-P-T capacity with a reliable P-V-T equation of state (EoS) for olivine, we further modeled the thermodynamic Grüneisen parameter, γ(P-T). The Grüneisen parameter is important for the connection between isothermal and adiabatic compressions of minerals, which can be decreased by approximately 5% with the anharmonic correction at high temperatures. The modeled adiabatic bulk modulus and bulk sound velocity can be expressed as: KS(T,P) (GPa) = 127.5(1) + 4.32(5)∙P – 0.018(1)∙(T – 300) and VΦ(T-P) (km/s) = 6.22(2) + 0.069(3)∙P – [3.74(15)–0.075(13)∙P]∙10–4∙(T – 300). The adiabatic temperature gradient, dTS/dP, which is almost independent of pressure, equals 13.40(16) and 12.35(16) K/GPa in the harmonic and anharmonic models, respectively. This study provides a useful example for modeling the radial temperature distribution in adiabatic planetary mantles.
Exact multi-instantons in topological string theory
Authors: Gu Jie , Mariño Marcos
Published: October 2023

Topological string theory has multi-instanton sectors which lead to non-perturbative effects in the string coupling constant and control the large order behavior of the perturbative genus expansion. As proposed by Couso, Edelstein, Schiappa and Vonk, these sectors can be described by a trans-series extension of the BCOV holomorphic anomaly equations. In this paper we find exact, closed form solutions for these multi-instanton trans-series in the case of local Calabi-Yau manifolds. The resulting multi-instanton amplitudes turn out to be very similar to the eigenvalue tunneling amplitudes of matrix models. Their form suggests that the flat coordinates of the Calabi-Yau manifold are naturally quantized in units of the string coupling constant, as postulated in large NN dualities. Based on our results we obtain a general picture for the resurgent structure of the topological string in the local case, which we illustrate with explicit calculations for local \mathbb{P}^2ℙ2.
Mental and Physical Development of Preschool Children Born After Assisted Reproduction
Authors: Bokhan Tatiana G. , Silaeva Anna V. , Leshchinskaia Svetlana B. , Terekhina Olga V.
Published: October 2023

This empirical study compared the mental (intellectual, personal, emotional, social) and physical development of four-year-old children conceived by assisted reproduction technology (ART) with that of naturally conceived children. The sample consisted of 90 ART children and 130 spontaneously conceived children (control). The research revealed no significant differences in behavior, emotional development, gender roles, intellectual development (visual-motor coordination, logical thinking, vocabulary, conceptual knowledge, speech development, counting and reading skills), physical development, emotional and behavioral eating habits, and dental health. The ART children demonstrated significantly higher symptoms of social developmental disorders and lower levels of categorizing skills, with a low effect size. The article introduces significant relationships across various components of mental development, as well as between mental and physical development of ART children vs. control. The majority of preschool children conceived by ART had normative development, but the study revealed a risk group and problem areas of development, which require monitoring and early correction.
Gender Stereotypes and Coping with Adversities
Authors: Belinskaya Elena P. , Avazmatova Farangis Kh.
Published: October 2023

Women’s subjective experience of life hardships may be connected with gender self-concept and misogynistic attitudes. This empirical study of external and internal misogyny as a gender stereotype consisted of two stages. The first stage relied on such quantitative methods as scale questionnaires to identify the coping strategies, self-attitudes, and misogynistic ideas. The second stage used two qualitative methods: the free associations method helped to define the concept of adversity in men and women while the thematic analysis identified the default coping strategies in the focus group. The study involved 312 women aged 18–45 y.o. from Tashkent, Uzbekistan. The research revealed a relationship between some parameters of self-attitude and the severity of misogynistic attitudes. For example, prominent self-confidence, self-acceptance, self-guidance, and openness in communication accompanied low scores for social vulnerability, personal inferiority, and a sense of danger. Internal conflicts and self-blame corresponded with strong misogynous attitudes. In general, the gender role remained a prevailing characteristic of adversity. The adversity concept demonstrated an inner contradiction: the core concentrated on sexual and physical family violence while the periphery was more about interpersonal family relations. The thematic analysis showed that the choice of coping strategy depended on the limitations caused by misogynistic attitudes. However, the relationship between the misogynistic gender stereotyping and the choice of coping strategy proved to be ambiguous.
Corporificações morais do futuro na escola
Authors: Monteiro Leonardo Henrique Brandão , Zuin Antonio Alvaro Soares
Published: October 2023

O artigo discute concepções de futuro de estudantes projetadas por eles mesmos ou sobre eles por outros atores escolares e as suas vinculações a certas moralidades, no ambiente escolar. Para tal, empreende reflexões que permitem compreender as maneiras pelas quais o futuro se corporifica no cotidiano da instituição escolar. A metodologia utilizada teve um viés etnográfico (Geertz, 2008) e complementou-se com uma série de entrevistas semiestruturadas. Na escola analisada, encontrou-se um fundo normativo intersubjetivo, compartilhado em maior ou menor grau, por todos. Esse fundo se manifestava articulado e atravessado por diversas outras moralidades e construía certo horizonte simbólico. Identificamos quatro tipos ideais que forneceram uma grade de inteligibilidade para os modos como o futuro era acionado nas relações cotidianas. Estes irão guiar a reflexão, mas não funcionam como destinos dos alunos ou posicionamentos fixos dos estudantes nesse espaço social.
Contribuições do exercício da imaginação sociológica para a construção do pensamento científico na formação de professores
Authors: Coêlho dos Santos Aline , Pereira Roberta Andressa , Buzzi Raush Rita
Published: October 2023

Este estudo destaca o desenvolvimento do pensamento científico como um saber fundamental para a profissionalização docente, diretamente associado à capacidade de contextualizar e problematizar o contexto de atuação, habilidade necessária para a reflexão da prática, bem como para a construção de situações-problema que possam mobilizar o trabalho docente. Tem-se por objetivo conhecer as contribuições do exercício da imaginação sociológica para o desenvolvimento do pensamento científico na formação de professores. Trata-se de um estudo teórico de abordagem qualitativa, no qual utiliza-se o procedimento bibliográfico pautado principalmente nas obras que versam sobre a imaginação sociológica na perspectiva de Mills e Giddens. Nesse âmbito, este manuscrito apresenta o exercício da imaginação sociológica, proposto pelos sociólogos Charles Wright Mills e Anthony Giddens como procedimento possível para o desenvolvimento do pensamento científico nos professores, que pode, inclusive, fazer-se presente em processos de formação docente.
Medical Image Processing based on Generative Adversarial Networks: A
Systematic Review
Authors: Liu Jun , Li Kunqi , Dong Hua , Han Yuanyuan , Li Rihui
Published: October 2023

Background::

Generative adversarial networks (GANs) have demonstrated superior data generation capabilities compared to other methods, making them
popular for use in medical image applications. These features have intrigued researchers in the medical imaging field, resulting in a swift
implementation of these techniques in various conventional and novel applications such as image reconstruction, segmentation, detection,
classification, and cross-modality synthesis. A comprehensive review of recent medical imaging breakthroughs will benefit researchers interested
in this field. In this review, we aimed to introduce the origin, principle, and extended forms of GANs and summarize the state-of-the-art progress
of GAN-based medical image processing methods.

Methods::

We searched the literature for studies on Google Scholar and PubMed using the keywords “Segmentation,” “Classification,” “medical image,” and
“generative adversarial network.” Specifically, the initial search revealed 5423 publications after the removal of duplicated and non-accessible fulltext
publications. Then, after the title and abstract screening, 680 underwent full-text screening. Finally, 121 studies were included in our final
analysis after full-text screening.

Results::

The date range of the studies covered in this review is from January 1, 2017, to the present. After a thorough screening and qualification
assessment, 121 studies involving GAN-based applications in seven areas of medical images were included in the final methodological review.
These areas included synthesis, classification, segmentation, conversion, reconstruction, denoising, and lesion detection. We further classified and
summarized these papers into clinical applications, classification methods, and imaging modalities.

Conclusion::

We thoroughly examined the latest research progress of GAN-based medical image augmentation. These techniques effectively alleviate the
challenge of limited training samples for medical image diagnosis and treatment models. Furthermore, several critical issues associated with
GANs, such as pattern collapse, instability, and lack of interpretability, require attention in future research.
A Rapid and Sensitive UPLC-MS/MS Method for the Determination of
Bellidifolin and Pharmacokinetics Study of Bellidifolin Nano-microcells
Authors: Tian Jiaye , Bai Ran , Chen Ziyue , Qin Piaoran , Liu XingChao , Shen Haoran , Zhou Li , Guo Qiuhong
Published: October 2023

Background:

Bellidifolin (BEL) has a decent enemy of myocardial fibrosis impact, and
its preparation into nano-micelles can build security and great biocompatibility in vitro and in vivo.
The pharmacokinetic assessment of BEL can be utilized as the reason for the security and viability
of BEL in clinical use.

Objective:

This research aimed to establish an effective UPLC-MS/MS strategy for assuring BEL
in rodent plasma and concentrating on its pharmacokinetics in vivo.

Methods:

Luteolin was utilized as an internal standard (IS). Chromatographic separation was accomplished
utilizing a UPLC HSS T3 column (2.1 ×100 mm, 1.8 μm) section using a mobile phase
of 0.1% acetonitrile (A) and 0.1% formic acid in water (B) with gradient elution. Electrospray ionization
(ESI) coupled mass spectrometry was applied in various response checking (MRM) modes
with negative ionization.

Results:

The pharmacokinetic behaviour of bellidifolin nano-micelles in vivo showed that the peak
concentration (Cmax) was 1666.19±479.92 μg/L, the time to peak (Tmax) was 0.167 h, and the apparent
elimination half-life (t1/2) was 7.60±3.58 h. The plasma clearance rate (CL/F) was
1.15±0.48 L/h/kg, the apparent volume of distribution (V/F) was 14.38±11.04, the area under the
curve (AUC) was 8292.57±4193.13 μg/L*h, and the mean retention time (MRT) was 9.70±4.55 h.

Conclusion:

The method was successfully applied to the plasma pharmacokinetics of bellidifolin
nano-micelles after intragastric administration to rats.
Facility for validating technologies for the autonomous space rendezvous and docking to uncooperative targets
Authors: Sabatini M.
Published: October 2023

Abstract. We present the latest advancements in the air-bearing facility installed at La Sapienza's GN Lab in the School of Aerospace Engineering. This facility has been utilized in recent times to validate robust control laws for simultaneous attitude control and vibration active damping. The instrumentation and testbed have been restructured and enhanced to enable simulations of close proximity operations. Relative pose determination, accomplished through visual navigation as either an auxiliary or standalone system, is the first building block. Leveraging the acquired knowledge, optimal guidance and control algorithms can be tested for contactless operations (e.g. on-orbit inspection), as well as berthing and docking tasks.
Simulation of in-space fragmentation events
Authors: Olivieri L.
Published: October 2023

Abstract. In the next years the space debris population is expected to progressively grow due to in-space collisions and break-up events; in addition, anti-satellite tests can further affect the debris environment by generating large clouds of fragments. The simulation of these events allows identifying the main parameters affecting fragmentation and generating statistically accurate populations of generated debris, both above and below detection thresholds for ground-based observatories. Such information can be employed to improve current fragmentation models and to reproduce historical events to better understand their influence on the non-detectable space debris population. In addition, numerical simulation can also be employed to identify the most critical object to be removed to reduce the risk of irreversible orbit pollution. In this paper, the simulation of historical in-orbit fragmentation events is discussed and the generated debris populations are presented. The presented case-studies include the COSMOS-IRIDIUM collision, the COSMOS 1408 anti-satellite test, the 2022-151B CZ-6A in-orbit break-up, and a potential collision of ENVISAT with a spent rocket stage; for these events, results are presented in terms of cumulative fragments distributions and debris orbital distributions.
The new transmitting antenna for BIRALES
Authors: Bianchi G.
Published: October 2023

Abstract. In the last decades the increasing Resident Space Objects (RSOs) population is fostering many Space Surveillance and Tracking (SST) initiatives, which are currently based on the use of ground sensors. These can be distinguished in optical, laser and radar and categorized in tracking and survey sensors. In particular, the survey radars allow to determine the orbit of both catalogued and uncatalogued objects. Italy contributes to the European SST (EUSST) activities with the BIstatic RAdar for LEo Survey (BIRALES), whose transmitter is the Radio Frequency Transmitter (TRF), located at the Italian Joint Test Range of Salto di Quirra in Sardinia, and whose receiver is a portion of the Northern Cross Radio Telescope, located at the Medicina Radio Astronomical Station, near Bologna. The current sensor configuration is undergoing an upgrade process, including the receiver field of view extension and a new transmitter station. The purpose of the work is to present the new transmitting antenna of BIRALES, showing its technological progress and the potential for the monitoring of space debris. The final objective is to produce a high technological radar to improve the performance of the EUSST sensors network. In particular, the aim is to increase both the number of detectable objects and the sensitivity to detect fragments of a few centimetres up to an altitude of 2,000 km, with a remarkable improvement of orbit determination procedures and quality. The transmitting antenna has been designed to be very flexible for any type of observations, modifying its parameters depending on the observation needs and according to the service to offer (monitoring of fragments, re-entry or for collision avoidance). The work presents the system architecture and the transmitting antenna structure, and the performance are assessed through numerical simulations.
Space object identification and correlation through AI-aided light curve feature extraction
Authors: Bertolini C.
Published: October 2023

Abstract. With the constant growth of objects in orbit, the monitoring and cataloging of space population is essential. Light curves obtained from ground stations support this point, providing valuable information about the observed objects. The idea of using them to identify an object through correlation with a catalogued reference takes hold from their wide availability. This article focuses on the development of a tool for the analysis and correlation of two light curves, ARIEL. This tool is built through neural networks and declined in three strategies, each with its own goal: ROGUE, LINDEN and SIERRA. The light curves were retrieved via the database managed by the Mini-MegaTORTORA observatory and filtered using the Savitzky-Golay filter.
Ten years of aero-servo-elastic tests at large POLIMI’s wind tunnel for active flutter control and loads alleviation
Authors: Ricci S.
Published: October 2023

Abstract. Born in the autumn of 2001, but fully operational since 2023, the large wind tunnel of Politecnico di Mlano turns 20 this year and today it is one of the 4 large research infrastructures of the University. Designed, from the point of view of fluid dynamics, entirely within Politecnico, it is close circuit wind tunnel characterized by a particular design that includes two test sections. The boundary layer section (14m x 4m x 38m), located in the return circuit, is particularly suitable for testing objects subjected to the action of the wind such as bridges, skyscrapers, stadiums and large roofing systems; this section is widely used for research in the wind energy sector. The low turbulence section (4m x 4m x 6m), located as usual between the convergent and divergent parts of the tunnel, is mainly used for aeronautical tests, such as airplanes and helicopters, but not only. Suffice it to recall the numerous tests carried out in the field of sport aerodynamics, because the dimensions allow the equipment to be tested directly with the athletes. The paper briefly describes
AUTOMA project: technologies for autonomous in orbit assembly operations
Authors: Caon A.
Published: October 2023

Abstract. The possibility of manipulating objects in space is at the basis of the In-Orbit Servicing missions with the purpose to extend or improve the life of existing satellites. This can be obtained by equipping a target satellite with additional modules capable of providing additional basic functions, like power, thrust or communication. One of the most promising technologies to accomplish to these purposes is presented by space robots (satellites with one or more robotic manipulators) equipped with dedicated tool. The manipulators have the dual purposes to capture the additional module and to manipulate and attach it to the target satellite. In order to advance in IOS technologies, the Department of Industrial Engineer has funded the AUTOMA (AUtonomous Technologies for Orbital servicing and Modular Assembly) project . The project aims to (1) upgrade an autonomous capture tool, (2) develop the additional module (EAU), and (3) execute tests in relevant laboratory scenarios. The autonomous tool is represented by SMACK (SMArt Capture Kit). SMACK is a capture system equipped with (1) different types of sensors to measure the relative pose during the entire approach for the capture and for the assembly; (2) a set of actuators to capture the module and keep a rigid connection during the manipulation; (3) a computer to execute locally the required software like guidance and navigation algorithms. The external module (Elementary Assembly Unit, EAU) is equipped with three features to be captured and manipulated by SMACK and a docking system to allow the assembly on the target structure. In order to test the assembly phase, SMACK has been mounted on the end-effector of a 6 degrees of freedom robotic arm in laboratory environment, while the target has been fixed on a frame. These tests proved the ability of SMACK to manage assembly tasks such as the control of a robotic arm with sufficient accuracy.
Simulations for in-flight stellar calibration aimed at monitoring space instruments optical performance
Authors: Chiara C.
Published: October 2023

Abstract. Stellar in-flight calibrations have a relevant impact on the ability of space optical instruments, such as telescopes or cameras, to provide reliable scientific products, i.e. accurate calibrated data. Indeed, by using the in-flight star images, the instrument optical performance can be checked and compared with the on-ground measurements. The results of the analysis of star images, throughout the whole instrument lifetime in space, will allow tracking the changes in instrument performance and sensitivity due to optical components degradation or misalignment. In this paper we present the concept, the necessary input and the available outputs of the simulations performed to predict the stars visible in the FoV of a specific space instrument. As an example of the method, its application to two specific cases, i.e, Metis coronagraph on-board Solar Orbiter and the stereo camera STC on-board BepiColombo, will be given. Indeed, due to their operation in proximity to the Sun, and also to Mercury for STC, both instruments operate in a hostile environment, are subjected to high temperatures and experience high temperature variations. Performance optical monitoring is thus extremely important.
Studies in hydrogen micromix combustor technologies for aircraft applications
Authors: French A.
Published: October 2023

Abstract. Within the context of future aircraft turbine engine development technology, hydrogen has fast become one of the most favored candidates as an alternative fuel due to the possibility of producing extremely low levels of pollutants in particular NOx. The principal component of such an engine technology is the hydrogen micro-mix combustor which provides a solution to safe hydrogen combustion avoiding auto-ignition and flashbacks by addressing novel methods of hydrogen-air mixing. The current design concepts include a typical injection manifold composed of multiple concentric arrays of micro-mix combustors which produce hundreds of miniature low temperature diffusion flames having very low NOx levels.
The Janus COM mechanism onboard the JUICE probe to the Jovian system
Authors: Colombatti G.
Published: October 2023

Abstract. After the successful launch of the JUICE (JUpiter ICy moons Explorer) on the 14th of April 2023 all the on board subsystems and instrument are testing their functionalities. The JANUS (Jovis, Amorum ac Natorum Undique. Scrutator) telescope is the imaging system on board the spacecraft and is an optical camera devoted to the study of global, regional and local morphology and processes on the Jovian moons, and to perform mapping of the clouds on Jupiter. Following the heritage of the successful design of the OSIRIS WAC camera, on board the Rosetta mission, the group of researchers at CISAS “Giuseppe Colombo”- Università degli studi di Padova, led by prof. S. Debei, in collaboration with colleagues of the Leonardo spa Company developed the mechanism responsible for the protection of the telescope during cruise phase. The COver Mechanism (COM) provides the external closure of the JANUS Optical Head Unit (OHU). It shields the optical parts from contamination, it is light and dust tight and works in the plane of the telescope entrance window avoiding the exposure of the inner surface of the cover itself and the core part of the telescope to the external dust and pollution. The lower part of the cover provides, also, a reference surface for the in-flight calibration of the telescopes. The main functional and environmental requirements of this mechanism can be identified and summarized as follows: the door provides optics and detector protection from sunlight and contamination; the subsystem, located at the main entrance of the JANUS OHU outer Baffle, provides the function of opening and closing of the cover. The opened Cover allows the JANUS OHU and detector to face the outer environment to perform planetary observations during science mission phases and to perform in-flight calibration observation of different targets (e.g., moons, stellar fields). This paper presents the design, the mechanical solutions adopted for a reliable system and the results of the test performed on ground in order to qualify the JANUS COM mechanism before flight.
Pushing the limits of re-entry technology: an overview of the Efesto-2 project and the advancements in inflatable heat shields
Authors: Guidotti G.
Published: October 2023

Abstract. As space exploration technology advances, the need for reliable re-entry systems becomes increasingly critical. The European Flexible Heat Shields: Advanced TPS Design and Tests for Future In-Orbit Demonstration – 2 (EFESTO-2) project is a Horizon Europe-funded initiative aimed at improving the Technology Readiness Level of Inflatable Heat Shields (IHS), an innovative thermal protection system that can be deployed during re-entry. The project seeks to further advance the work achieved in the EFESTO project, with a focus on expanding investigations into critical aspects of IHS and increasing the confidence level and robustness of the tools and models used in the field. The EFESTO-2 project is built on four pillars, including consolidating the use-case applicability through a business case analysis for a meaningful space application, extending the investigation spectrum of the father project EFESTO to other critical aspects of the IHS field, increasing the confidence level and robustness of tools/models, and consolidating the roadmap to guarantee continuity in presiding the IHS field in Europe among the scientific and industrial community. This paper provides an overview of the EFESTO-2 project's objectives, achievements, ongoing activities, and planned activities up to completion. The project's advancements in the fields of thermal protection systems, inflatable heat shields, and technology readiness level are described in detail, highlighting the project's contributions to the European re-entry technology roadmap. Through this project, the European Space Program aims to push the limits of re-entry technology and reinforce its position as a leader in innovative technology for space exploration. This project has received funding from the European Union’s Horizon Europe research and innovation program under grant agreement No 1010811041.
The Hera Milani mission
Authors: Cardi M.
Published: October 2023

Abstract. Hera is the European part of the Asteroid Impact & Deflection Assessment (AIDA) international colaboration with NASA who is responsible for the DART (Double Asteroid Redirection Test) kinetic impactor spacecraft. Hera will be launched in October 2024 and will arrive at Didymos in January 2027. The Hera mothercraft will accommodate two 6U Nanosatellite, Milani and Juventas. The Milani Nanosatellite is developed by Tyvak International leading a consortium of European Universities, Research Centers and Firms from Italy, Czech Republic, Finland. During the cruise to the Asteroid (+2 years), Milani Nanosatellite will be hosted inside the Hera mothercraft, periodically checked for health and charged. At arrival it will be deployed and commissioned while HERA is performing the Didymos detailed characterization phase, at about 10 to 20 km distance from the asteroid.  The Milani mission objectives are defined as to add scientific value to the overall Hera mission: i) Map the global composition of the Didymos asteroids, ii) Characterize the surface of the Didymos asteroids, iii) Evaluate DART impacts effects on Didymos asteroids and support gravity field determination, iv) Characterize dust clouds around the Didymos asteroid, enhancing the scientific return of the whole HERA mission. The scientific payloads supporting the achievement of these objectives are the main Payload “ASPECT” (developed by VTT, Finland), a SWIR, NIR and VIS imaging spectrometer and the secondary Payload “VISTA” (developed by INAF, Italy), a thermogravimeter aiming at collecting and characterizing volatiles and dust particles below 10µm.  The Milani mission and the project team is facing challenges such as, among others, the use of COTS components in deep space environment, optical navigation implementation, interfaces management with the HERA mothercraft since the very beginning of the design up to the mission. Tyvak International work focuses on the development and integration of the Milani vehicle, including mission specifics development enabling the mission and vehicle models enabling early interface testing with Hera mothercraft.
Small celestial body exploration with CubeSat Swarms
Authors: Blazquez E.
Published: October 2023

Abstract. This work presents a large-scale simulation study investigating the deployment and operation of distributed swarms of CubeSats for interplanetary missions to small celestial bodies. Utilizing Taylor numerical integration and advanced collision detection techniques, we explore the potential of large CubeSat swarms in capturing gravity signals and reconstructing the internal mass distribution of a small celestial body while minimizing risks and Delta V budget. Our results offer insight into the applicability of this approach for future deep space exploration missions.
Analytic formulation for J2 perturbed orbits
Authors: Sgubini S.
Published: October 2023

Abstract. The paper deals with a technique developed along the years at the Scuola di Ingegneria Aerospaziale to provide an exact solution for J2 perturbed orbits, here applied to spacecraft formations. Analytic solutions are useful in the design phase and can help in operations to identify and to efficiently maintain a suitable configuration. The approach is based on the elaboration, conveniently performed by means of a symbolic software tool, of a set of equations analogous to the Lagrange planetary relations. Resulting parameters are expressed through Fourier series depending only on the initial conditions. Comparison with standard, longer to obtain and less accurate numerical propagation clarify the advantage of the technique, which is limited only by the number of terms taken into account in the expansion.
An overview of the ArgoMoon and LICIAcube flight dynamics operations
Authors: Lombardo M.
Published: October 2023

Abstract CubeSats are becoming a reliable alternative for low-cost space applications in deep space, as mission companions or as standalone missions. The use of CubeSats in deep space requires to address many operational challenges, particularly those related to navigation. LICIACube and ArgoMoon are the first two 6U CubeSat missions to the outer space funded and managed by the Italian Space Agency, whose spacecrafts have been developed and operated by Argotec. The flight dynamics operations of both missions were performed by the flight dynamics team of the University of Bologna using NASA/JPL’s navigation software MONTE. This paper gives a brief presentation of the flight dynamics operations of ArgoMoon and LICIACube and presents the obtained results highlighting the challenges of cis-lunar and deep space CubeSat navigation as well as the achieved successes.
Re-entry predictions of space objects and impact on air traffic
Authors: Bernelli-Zazzera F.
Published: October 2023

Abstract. This work focuses on predicting the re-entry of an uncontrolled re-entry vehicle (RV) and how this affects air traffic. It includes the propagation of the nominal trajectory and that of the fragments resulting from the breakup of the object. The breakup does not occur at a fixed altitude but is a consequence of the thermal and dynamic loads acting on the RV as it re-enters the atmosphere. The purpose of the analysis is to identify a dangerous area at specific heights (flight levels) to be evacuated in time for air traffic. The hazard area is defined as that which includes all the impact points of the fragments at this altitude taking into account the additional safety margins. The study also considers the presence of uncertainties affecting the initial state of the vehicle. Accordingly, a Monte Carlo analysis is performed to predict the worst-case scenario and to better estimate the hazard area. Once the area has been defined, an evacuation algorithm calculates, for each aircraft, the trajectory changes necessary to clear or avoid the zone over time.
Update on green chemical propulsion activities and achievements by the University of Padua and its spin-off T4I
Authors: Barato F.
Published: October 2023

Abstract. In recent years, there has been a great research interest on green propulsion, both for environmental, cost and ease-of-use considerations, further accelerated by the needs of the NewSpace Economy. Hydrogen peroxide is a green and versatile propellant that is suitable for a lot of different uses in space applications. Following a previous AIDAA publication of 2019, this paper updates the research performed on hydrogen peroxide-based propulsion by the University of Padua and its spin-off T4i with the latest achievements. Starting from the simplest propulsion systems, several monopropellant thrusters have been successfully designed and tested, ranging from a propulsion module of 1 N, to a 10 N and 200 N flight-weight items. The thrusters can operate in blowdown or pressure-regulated mode, and they have been tested for hundreds of seconds of continuous operation and for thousands of pulses. A 450 N liquid bipropellant motor that burns the monopropellant exhausts with diesel fuel has also been developed and tested. The motor uses an unconventional internal vortex flow field to achieve stability, efficiency, and self-cooling of the chamber. The nozzle throat region temperature is kept under control by regenerative cooling channels fed by the peroxide. All thrusters make extensive use of additive manufacturing. The hydrogen peroxide technology has also been applied on hybrid propulsion, which was the initial main expertise of the Padua University propulsion group. Hundreds of tests have been performed at lab-scale, mainly with paraffin wax and polyethylene as fuels, with burning time up to 80 seconds. The motors are able to start, stop and restart multiple times. A cavitating pintle valve has been developed in house in order to control the oxidizer mass flow. With this valve, the hybrid motors are able to throttle the thrust in a range of 1:12.6. A similar valve has been also employed in the integrated monopropellant propulsion system of a lunar drone, composed by a 400 N throttleable engine together with 4 small 14 N on-off attitude control thrusters. Moreover, several dozens of hybrid tests have been performed at 5-10 kN scale up to 50 seconds. Finally, a composite sounding rocket powered by a pressure-regulated 5 kN hybrid rocket has been fully designed and successfully flight tested.
1D numerical simulations aimed to reproduce the operative conditions of a LOx/LCH4 engine demonstrator
Authors: Romano A.
Published: October 2023

Abstract. The present paper describes the results of the numerical simulations performed by means of the “EcosimPro” software, aimed at reproducing the operative conditions of the regenerative thrust chamber “DEMO-0A” designed by the Italian Aerospace Research Center. The operative conditions simulated are both cold flow and firing conditions. A validation of the numerical cold flow results has been performed by comparing them with the experimental data gathered during a cold flow campaign. Once validated the cold flow numerical model, various hot test conditions of the demonstrator have been simulated by considering different heat wall exchange coefficient correlations, in order to obtain information about the thermal power released during the combustion process and to assess the simulation capabilities of the “EcosimPro” software in predicting the behaviour of the demonstrator in firing conditions by modelling it with a 1-D approach.
Fast reconfiguration maneuvers of a micro-satellite constellation based on a hybrid rocket engine
Authors: Sannino A.
Published: October 2023

Abstract. In this work, the formation flight of the CubeSat cluster RODiO (Radar for Earth Observation by synthetic aperture DIstributed on a cluster of cubesats equipped with high-technology micro-propellers for new Operative services [1]) with respect to a small satellite in LEO (Low Earth Orbit) has been analyzed. RODiO is an innovative mission concept funded by the Italian Space Agency (ASI) in the context of the Alcor program [2]. The small satellite is equipped with an antenna that allows it to function as a transmitter, whereas RODiO functions as a receiver. The extension of the virtual SAR (Synthetic Aperture Radar) antenna can be achieved by establishing an along-track baseline performing an orbital coplanar maneuver (a phasing maneuver). Another interesting scenario is the possibility to create a cross-track baseline performing an inclination change maneuver, useful for stereoradargrammetric applications. Such formation reconfiguration maneuvers can be achieved in relatively short times only by use of a high-thrust propulsion system, i.e. based on conventional chemical technologies. From the study of maneuvers, it is possible to identify the required ∆V, which represents an input parameter for the design of propulsion system. Among the different kinds of propulsion systems, a Hybrid Rocket Engine was chosen for its safety, compactness and re-ignition and throttle capabilities.
Thermite-for-demise (T4D): thermite characteristics heuristic optimization on object- and spacecraft-oriented re-entry models
Authors: Finazzi A.
Published: October 2023

Abstract. The major hazard associated with uncontrolled atmospheric re-entry is the casualty risk on ground. An innovative concept to support spacecraft demise that is now under investigation is the use of exothermic reactions. Thermites are good candidates for this role, being capable of releasing a noticeable amount of heat upon ignition. An appropriate selection of the metal-metal oxide couple can grant a formulation that is compliant with the main space operation needs, e.g., that is relatively insensitive to external stimuli and non-toxic. To support the selection of the energetic material for the experimental tests in the ESA-founded project SPADEXO and to preliminarily size the charge to be placed on board, the object-oriented code TRANSIT has been developed. This software has been compared to ESA’s spacecraft-oriented code SCARAB (developed by HTG), that is capable to predict spacecraft re-entry with the highest possible level of detail. Both the models were subjected to a genetic algorithm optimization process to identify the best thermite properties and the foreseen energetic material mass for simple geometries applications. In this paper, the SCARAB results obtained for one geometry will be presented and compared with the ones retrieved by TRANSIT.
Validation of a numerical strategy to simulate the expansion around a plug nozzle
Authors: Gagliardi M.D.
Published: October 2023

Abstract. Rocket engines currently use traditional bell-shaped nozzles that have a fixed area ratio and can only operate at maximum efficiency at a given altitude. Plug nozzles have been proposed as an alternative solution to achieve higher performance over a larger altitude range. Unlike bell nozzles, the flow is free to expand along the plug, as it is no longer surrounded by solid boundaries. Therefore, plug nozzles can adapt to different altitudes by expanding the flow to ambient pressure, resulting in continuous altitude adaptation. Due to the high surface area that needs to be cooled, one of the main challenges of plug nozzle design is thermal management. However, the introduction of aerospike geometry, which is essentially a truncated plug nozzle, has helped mitigate this issue. Simulating an aerospike engine is challenging due to the interaction between the plume and the external flow, which is necessary to accurately predict thrust. In this work, a numerical strategy for predicting the performance of an aerospike engine, during a static fire, was developed and validated.
Solar simulator facility for the verification of space hardware performance
Authors: Bettanini C.
Published: October 2023

Abstract. The paper presents the main characteristics of the high flux solar simulator facility designed and developed at University of Padova as key enabling technology to evaluate the effectiveness of satellite hardware for missions to the inner planets of the Solar System. The designed solar simulator can reproduce the intensity and spectral distribution of the Sun's radiation up to 8 Solar constants (around 10000 Watt/m2) and the emitted flux can be directed to the viewport of a Thermal Vacuum Chamber in order to test the performance of space equipment under representative pressure and temperature conditions. Angles of incidence between 30° and 90° can be achieved using a motorised setup within the thermal chamber while different intensities of sunlight can be obtained by properly choosing the emitting lamp and regulating the electric power. After the verification of optical path alignment, a series of tests has been conducted to evaluate the flux homogeneity installing a commercial pyranometer on cartesian reference and moving the slide within the target area. A final Class A classification for the spatial non-uniformity of irradiance as for ASTM E927-19 has been achieved for the central target area. The facility has afterwards operated for validation campaign of satellite radiators in simulated orbital condition, verifying the repeatability of reproduced flux during continuous long-term operation.
Trajectory reconstruction by means of an event-camera-based visual odometry method and machine learned features
Authors: Chiodini S.
Published: October 2023

Abstract. This paper presents a machine learned feature detector targeted to event-camera based visual odometry methods for unmanned aerial vehicles trajectory reconstruction. The proposed method uses machine-learned features to enhance the accuracy of the trajectory reconstruction. Traditional visual odometry methods suffer from poor performance in low light conditions and high-speed motion. The event-camera-based approach overcomes these limitations by detecting and processing only the changes in the visual scene. The machine-learned features are crafted to capture the unique characteristics of the event-camera data, enhancing the accuracy of the trajectory reconstruction. The inference pipeline is composed of a module repeated twice in sequence, formed by a Squeeze-and-Excite block and a ConvLSTM block with residual connection; it is followed by a final convolutional layer that provides the trajectories of the corners as a sequence of heatmaps. In the experimental part, a sequence of images was collected using an event-camera in outdoor environments for training and test.
The wide angle camera of rosetta
Authors: Naletto G.
Published: October 2023

Abstract. Rosetta was the ESA cornerstone missions which investigated the comet 67P/Churuymov-Gerasimenko. One of the on board instruments was the OSIRIS imaging system, which included the Wide Angle Camera. This camera was designed, realized, integrated, aligned and tested at the Padova University. Several challenges had to be faced and solved, due to stringent requirements and the very peculiar mission profile which foresaw a long interplanetary travel with very different thermal environments. Rosetta has been a very successful mission which returned plenty of fundamental information about comets and more in general about the solar system origin. In this paper we summarize the main characteristics of the WAC and describe one of the many scientific results that it had returned.
Development of a modular central electronic unit (CEU) for data handling and management in Martian atmosphere investigations
Authors: Marrocchi L.
Published: October 2023

Abstract. This article describes the development of a highly modular Central Electronic Unit (CEU) for data handling and management in Martian atmosphere investigations as part of the DREAMS experiment in ExoMARS 2016 Mission. The CEU was developed by TEMIS and Centro Interdipartimentale di Studi e Attività Spaziali G. Colombo (CISAS) to handle, acquire and transmit medium and low-rate data from sensors dedicated to investigating the Martian atmosphere. The CEU subsystem was designed to communicate with an external host to receive commands and transfer telemetry, transform power from different sources, perform sensors' switch on and off, acquire scientific sensors and their housekeeping monitors, and provide CEU health status. The high modularity of the CEU architecture makes it easy to customize and interface with different types of equipment and instrumentation for various missions. The CEU subsystem is housed on Entry and Descent Module (EDM) and serves as the data handling platform of the DREAMS payload for the EXOMARS 2016 Mission. The CEU has proven to be an effective and flexible solution for data handling and management in Martian atmosphere investigations.
SIMBIO-SYS, the remote sensing instruments on board the BepiColombo mission
Authors: Cremonese G.
Published: October 2023

Abstract. The SIMBIO-SYS (Spectrometer and Imaging for MPO BepiColombo Integrated Observatory SYStem) is a complex instrument suite part of the scientific payload of the Mercury Planetary Orbiter for the BepiColombo mission, the last of the cornerstone missions of the European Space Agency (ESA) Horizon + science program. It will explore Mercury, the closest planet to the Sun. The SIMBIO-SYS instrument will provide all the science imaging capability of the BepiColombo MPO spacecraft. It consists of three channels: the STereo imaging Channel (STC), with broad spectral band in the 410-930 nm range and medium spatial resolution (up to 60 m/px), that will provide Digital Terrain Model of the entire surface of the planet with an accuracy better than 80 m; the High Resolution Imaging Channel HRIC), with broad spectral bands in the 530-900 nm range and high spatial resolution (up to 6 m/px), that will provide high resolution images of about 10% of the surface, and the Visible and near-Infrared Hyperspectral Imaging channel (VIHI), with high spectral resolution (up to 6 nm) in the 400-2000 nm range and spatial resolution up to 120 m/px, it will provide the global coverage at 480 m/px with the spectral information, assuming the first orbit around Mercury with periherm at 480 km from the surface. It has been funded by the two space agencies, ASI (Italian Space Agency) and CNES (French Space Agency) and it is the result of the collaboration between more than 100 scientists and engineers of 12 different countries all over the world, with the Italian prime contractor Leonardo spa. It is the first time that a planetary mission has three remote sensing instruments integrated in a system, sharing the Main Electronics, and under the responsibility of one team.