Satellite Structure Research Articles

A co-rotating gas and satellite structure around the interacting galaxy pair NGC 4490/85

ABSTRACT The interacting binary system NGC 4490/85 = Arp 269 is intermediate in mass between the Milky Way/Large Magellanic Cloud and the Large/Small Magellanic Cloud binary systems. It is a system of 14 known galaxies. We estimate the total Newtonian gravitating mass of the NGC 4490/85 group to be $M_\mathrm{ T} = (1.37\pm 0.43) \times 10^{12} \, \mathrm{M}_{\odot }$ using radial velocities and projected separations of its 13 candidate members. The system of dwarf satellites in the group demonstrates signs of coherent rotation in the same direction as that of the extended H i-shell surrounding the central interacting galaxy pair. The origin of this phase-space correlated population of star-forming late-type satellite galaxies raises questions in view of the planes-of-satellites observed around more massive galaxy pairs that are, however, made up of old early-type dwarf galaxies. We also report the detection of a candidate stellar Plume near the binary. This elongated structure of low surface brightness is a likely optical counterpart to the H i-tail north of NGC 4490/85, recently discovered by the Five-Hundred-meter Aperture Spherical radio telescope.

NiO as Hole Transporting Layer for Inverted Perovskite Solar Cells: A Study of X‐Ray Photoelectron Spectroscopy

AbstractHygroscopic and acidic nature of organic hole transport layers (HTLs) insisted to replace it with metal oxide semiconductors due to their favorable charge carrier transport with long chemical stability. Apart from large direct bandgap and high optical transmittance, ionization energy in the range of −5.0 to −5.4 eV leads to use NiO as HTL due to good energetic matching with lead halide perovskites. Analyzing X‐ray photoelectron spectroscopic (XPS) data of NiO, it is speculated that p‐type conductivity is related to the NiOOH or Ni2O3 states in the structure and the electrical conductivity can be modified by altering the concentration of nickel or oxygen vacancies. However, it is difficult to separate the contribution from nonlocal screening, surface effect and the presence of vacancy induced Ni3+ ion due to very strong satellite structure in the Ni 2p XPS spectrum of NiO. Thus, an effective approach to analyze the NiO XPS spectrum is presented and the way to correlate the presence of Ni3+ with the conductivity results which will help to avoid overestimation in finding the oxygen‐rich/deficient conditions in NiO.

Rapid formation of gold core-satellite nanostructures using Turkevich-synthesized satellites and dithiol linkers: the do's and don'ts for successful assembly.

Turkevich syntheses represent a foundational approach for forming colloids of monodisperse gold nanoparticles where the use of these structures as building blocks when forming multicomponent nanoassemblies is pervasive. The core-satellite motif, which is characterized by a central core structure onto which satellite structures are tethered, distinguishes itself in that it can realize numerous plasmonic nanogaps with nanometer scale widths. Established procedures for assembling these multicomponent structures are, to a large extent, empirically driven, time-consuming, difficult to reproduce, and in need of a strong mechanistic underpinning relating to the close-range electrostatic interactions needed to secure satellite structures onto core materials. Described herein is a rapid, repeatable procedure for assembling core-satellite structures using Turkevich-grown satellites and dithiol linkers. With this successful procedure acting as a baseline for benchmarking modified procedures, a rather complex parameter space is understood in terms of timeline requirements for various processing steps and an analysis of the factors that prove consequential to assembly. It is shown that seemingly innocuous procedures realize sparsely populated cores whereas cores initially obstructed with commonly used capping agents lead to few disruptions to satellite attachment. Once these factors are placed under control, then it is the ionic strength imposed by the reaction biproducts of the Turkevich synthesis that is the critical factor in assembly because they decide the spatial extent of the electrical double layer surrounding each colloidal nanoparticle. With this understanding, it is possible to control the ionic strength through the addition or subtraction of various ionic species and assert control over the assembly process. The work, hence, advances the rules for a robust core-satellite assembly process and, in a broader sense, contributes to the knowhow required for the precise, programmable, and controllable assembly of multicomponent systems.

Cumulant Green's function methods for molecules.

The cumulant expansion of the Green's function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, ab initio cumulant expansions performed on top of GW (GW + C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW + C have been published on molecular systems. Here, we assess the performance of this scheme on a series of 10-electron molecular systems (Ne, HF, H2O, NH3, and CH4) where full configuration interaction estimates of the outer-valence quasiparticle and satellite energies are available.

A combination of long- and short-read genomics reveals frequent p-arm breakpoints within chromosome 21 complex genomic rearrangements

PurposeAlthough chromosome 21 is the smallest human chromosome, it is highly relevant in the pathogenicity of both cancer and congenital diseases, including Alzheimer disease and trisomy 21 (Down syndrome). In addition, cases with rare structural variants (SVs) of chromosome 21 have been reported. These events vary in size and include large chromosomal events, such as ring chromosomes and small partial aneuploidies. The p-arm of the acrocentric chromosome 21 was devoid of reference genomic sequence in GRCh37 and GRCh38, which hampered our ability to solve genomic rearrangements and find the mechanism of formation of disease-causing SVs. We hypothesize that conserved satellite structures and segmental duplications located on the p-arm play an important role in the formation of complex SVs involving chromosome 21. MethodsThree cases with complex chromosome 21 rearrangements were studied with a combination of short-read and long-read genome sequencing, as well as optical genome mapping. The data were aligned to the T2T-CHM13 assembly. ResultsWe were able to resolve all 3 complex chromosome 21 rearrangements in which 15, 8, and 26 breakpoints were identified, respectively. By comparing the identified SV breakpoints, we were able to pinpoint a region between 21p13 and 21p12 that appears to be frequently involved in chromosome 21 rearrangements. Importantly, we observed acrocentric satellite DNA at several breakpoint junctions suggesting an important role for those elements in the formation of complex SVs. ConclusionTaken together, our results provide further insights into the architecture and underlying mechanisms of complex rearrangements on acrocentric chromosomes.

Microwave Radiation Characteristics and Generation Mechanism of 2A12Al Simulated Satellite Structure Generated by High-Velocity Impact of Al/Ep Energetic Projectiles

Microwave Radiation Characteristics and Generation Mechanism of 2A12Al Simulated Satellite Structure Generated by High-Velocity Impact of Al/Ep Energetic Projectiles

On Topology Optimisation Methods and Additive Manufacture for Satellite Structures: A Review

Launching satellites into the Earth’s orbit is a critical area of research, and very demanding satellite services increase exponentially as modern society takes shape. At the same time, the costs of developing and launching satellite missions with shorter development times increase the requirements of novel approaches in the several engineering areas required to build, test, launch, and operate satellites in the Earth’s orbit, as well as in orbits around other celestial bodies. One area with the potential to save launching costs is that of the structural integrity of satellites, particularly in the launching phase where the largest vibrations due to the rocket motion and subsequent stresses could impact the survival ability of the satellite. To address this problem, two important areas of engineering join together to provide novel, complete, and competitive solutions: topology optimisation methods and additive manufacturing. On one side, topology optimisation methods are mathematical methods that allow iteratively optimising structures (usually by decreasing mass) while improving some structural properties depending on the application (load capacity, for instance), through the maximisation or minimisation of a uni- or multi-objective function and multiple types of algorithms. This area has been widely active in general for the last 30 years and has two main core types of algorithms: continuum methods that modify continuous parameters such as density, and discrete methods that work by adding and deleting material elements in a meshing context. On the other side, additive manufacturing techniques are more recent manufacturing processes aimed at revolutionising manufacturing and supply chains. The main exponents of additive manufacturing are Selective Laser Melting (SLM) (3D printing) as well as Electron Beam Melting (EBM). Recent trends show that topology-optimised structures built with novel materials through additive manufacturing processes may provide cheaper state-of-the-art structures that are fully optimised to better perform in the outer-space environment, particularly as part of the structure subsystem of novel satellite systems. This work aims to present an extended review of the main methods of structural topology optimisation as well as additive manufacture in the aerospace field, with a particular focus on satellite structures, which may set the arena for the development of future satellite structures in the next five to ten years.

Flywheel Vibration Isolation of Satellite Structure by Applying Structural Plates with Elastic Boundary Instead of Restrained Boundary

Flywheels play a critical role as core components in satellite attitude control systems. However, their high-speed rotation inevitably generates vibrations that have a detrimental impact on the in-orbit imaging capabilities of high-precision remote sensing payloads. This study focuses on the passive vibration isolation design of satellite flywheels. The flywheel-mounted structural plate and flywheel vibration isolation platform are considered as a whole system (termed a plate-isolator system). In this system, the structural plate is treated as an elastomer. By simplifying the plate-isolator system as a 2-degree-of-freedom vibration system, it becomes evident that obtaining an ideal vibration isolation effect through the optimization of the flywheel vibration isolation platform (FVIP) alone is difficult. In order to enhance the passive vibration isolation effect for satellite flywheels, this study introduces the concept of an elastic boundary applied to the flywheel-mounted structural plate, thus treating the elastic boundary as a design factor. Consequently, the plate-isolator system can be simplified as a 3-stage vibration isolation system. The optimization of the elastic boundary condition of the structural plate is performed using the kinetic model of the simplified 3-stage system. The vibration isolation effect of the plate-isolator system with an elastic boundary is further confirmed through finite element simulation. The calculation results demonstrate that, after establishing a reasonable elastic boundary for the satellite structural plate, the overall vibration/force transmission rate of the plate-isolator system becomes similar to that of a single-degree-of-freedom dynamic system. Finally, the proposed concept is validated through kinetic response analysis of a cube satellite. The results reveal that the vibration amplitude of the satellite’s top and side structural plates can be effectively lowered if the elastic boundary condition is set for the flywheel-mounted bottom structural plate.

Rational design of Au NPs satellite nanostructure modified microelectrode for dual-mode detection of mercury ions in algal solution

Developing a microelectrode with in-situ multiple sensing modes will greatly expand the applicability and reliability of the analytical platform. Hence, a functional substrate with a satellite-like nanostructure was constructed on a gold microelectrode (Au ME). This structure not only amplifies the surface-enhanced Raman scattering (SERS) signal of the labeled molecule (4-nitrobenzenthiol, NBT) on the functionalized Au NPs, but also ensures the good electrical properties of the proposed functionalized microelectrode (Au ME/Au-AuNDNA). Based on this feature, the highly toxic heavy metal mercury ions (Hg2+) were used as a model to verify this dual modal analytical platform. Significantly, the proposed microelectrode has a satisfactory sensitivity to Hg2+and allows the simultaneous presentation of analytical results by dual-mode of SERS signal turn-off (LOD 2.7 × 10−11 M) and current signal turn-on (LOD 6.4 × 10−9 M), the detected concentration of Hg2+ is below the dangerous limit of World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA). This relies mainly on the formation of thymine-Hg2+-thymine (T-Hg2+-T) by the modified probe B ssDNA on the microelectrode to disrupt the satellite structure with AuNDNA, while the applied potential reduces the Hg2+ captured by T-Hg2+-T on the microelectrode surface. Such a fascinating analytical strategy was further evaluated in an environmental water sample simulated with algal solution and still showed a reliable analytical capability. Thus, the proposed dual-mode sensing concept not only opens new avenues for the coordinated application of novel electrochemical and SERS sensing techniques, but also provides a foundation for in-situ detection based on micro/nanoscale electrodes.

Design and Analysis of Cube Satellite Structure

Abstract: Currently, with new technologies, lower and cheaper satellites have been designed and launched. similar satellites fit as educational tools to unborn masterminds. With many kilograms and reduced confines, they've simple operation, despite being complete systems able to perform real operations. During CubeSat platform development, the conception of the design process is formulated and standard physical connections are proposed to find number of optimal design result in terms of introductory limitations and features comity. Specifically, new modular structure is proposed in order to allows flexible subsystems agreement. This paper checks and estimates the eventuality of one- unit CubeSat platform

The Fingerprints of Periodic Electric Fields on Line Shapes Emitted in Plasmas

Periodic electric fields are found in many kinds of plasmas and result from the presence of collective fields amplified by plasma instabilities, or they are created by external sources such as microwave generators or lasers. The spectral lines emitted by atoms or ions in a plasma exhibit a frequency profile characteristic of plasma conditions, such as the temperature and density of charged particles. The fingerprints of periodic electric fields appear clearly on the line shape for a large range of frequencies and magnitudes of the oscillating electric field. Satellite structures appear near to multiples of the oscillation frequency and redistribute the intensity of the line far from the line center. The modeling of the simultaneous effects of the plasma microfield and of a periodic electric field has been active since the seventies, but it remains difficult to be conducted accurately since the quantum emitter is submitted to several time-dependent electric fields, each with their own characteristic time. We describe here a numerical approach which couples a simulation of the motion of charged plasma particles with an integration of the emitter Schrödinger equation. Resulting hydrogen line shapes are presented for different plasmas and periodic fields encountered in laboratory and astrophysical plasmas.

Structural optimization of a small earth remote sensing satellite

Structural sizing optimization is a crucial step in the process of modern satellite structural design. It warrants minimizing the satellite structural mass while improving the overall quality and reliability of such design. This article discusses thoroughly the structural optimization of a small earth remote sensing satellite whose primary structure is based upon aluminum honeycomb sandwich plates. A novel contribution has been conducted in extending the optimization problem to include the main static and dynamic loads acting simultaneously on the satellite during launch phase utilizing the results of static, buckling, modal, and harmonic response analyses. The small satellite optimization process starts initially with formulating the optimization problem based upon the structural analyses results. Subsequently, miscellaneous optimization techniques utilizing ANSYS workbench capabilities represented in “DesignXplorer” module are employed. Finally, the results are compared with other results obtained from a MATLAB code based upon both genetic and sequential quadratic programming algorithms. The optimization process leads to approximately 30% mass reduction in the proposed satellite structure. A special attention is drawn towards meta-models due to their capabilities in solving complex structural models with a reasonable wall-clock time.

Moving morphable components structural optimum approach considering wire arc additive manufacturing constraint and its application in satellite

The thin-walled reinforced structure is important for achieving structural lightweight in spacecraft. With the rapid development of additive manufacturing technology, large-size, thin-walled, stiffened structures with complex structural forms can be manufactured. However, topology optimization considering manufacturing constraints has always been difficult in this field. This paper proposes a design method for reinforced structures that enables control over structural connectivity based on the Moving Morphable Components (MMC) method, which uses reinforced components with explicit geometrical parameters as primitives for topology optimization. The proposed method solves the challenges of rapidly designing complex geometric reinforcements, forming clear force transfer paths, and effectively reduces the structural topology optimization challenges caused by process constraints associated with the arc start/quench process of wire arc additive manufacturing (WAAM). This method was used to design a core load-bearing structure of a large satellite, i.e., the 3.5-meter tank supporting structure, which was fabricated by the WAAM process for the first time in the spacecraft field. The structure passed the mechanical test and eventually achieved a weight reduction of 31.6%.

Basic Principles and Mechanical Considerations of Satellites: A Short Review

AbstractSatellites are used for navigation, communication, oceanography, astronomy, etc.. Satellites come in a diversity of sizes and forms. Depending on the satellite’s mission, different subsystems are used. These subsystems are installed inside a housing to protect them from the space environment. This housing, which is also known as the satellite primary structure or mechanical structure, is made of durable materials that can endure severe conditions during launch and in the orbit. The optimisation of satellite mass is crucial right now since satellites are losing mass every day to reduce the cost of manufacturing and launching. This review first introduces an overview of the satellite classifications and subsystems. Then, the different types of mechanical load analysis the satellite subjects itself to are demonstrated. The advanced approaches for promoting the performance of the mechanical structures of satellites are explored, with a spotlight on the effect of the optimisation parameters of isogrid and honeycomb sandwich structures on the mechanical performance of the satellite primary structure. The assembly, integration and testing (AIT) of the small satellite are briefly presented. Finally, the important potential designs to improve the mechanical performance of the satellite primary structure and the challenges of further research are summarised.

Lightweight Design for Active Small SAR S-STEP Satellite Using Multilayered High-Damping Carbon Fiber-Reinforced Plastic Patch

In the launch environment, satellites are subjected to severe dynamic loads. These dynamic loads in the launch environment can lead to the malfunction of the payload, or to mission failure. In order to improve the structural stability of satellites and enable the reliable execution of space missions, it is necessary to have a reinforcement structure that reduces structural vibrations. However, for active small SAR satellites, the mass requirements are very strict, and this makes it difficult to apply an additional structure for vibration reduction. Therefore, we have developed a carbon fiber-reinforced plastic (CFRP)-based laminated patch to obtain a vibration reduction structure with a lightweight design for improving the structural stability of an S-STEP satellite. To verify the vibration reduction performance of the CFRP-based patch, sine and random vibration tests were conducted at the specimen level. Finally, the structural stability of the S-STEP satellite with the proposed CFRP-based laminated patch was experimentally verified using sine and random vibration tests. The validation results indicate that the CFRP-based laminated patch is an efficient solution which can effectively reduce the vibration response without the need for major changes to the design of the satellite structure. The lightweight vibration reduction mechanism developed in this study is one of the best solutions for protecting vibration-sensitive components.

Sodium 3s−3p far wing shapes induced by ground neon atoms

This study deals with the broadening of atomic sodium, evolving in a neon buffer gas, in the wavelength and temperature ranges 500 − − 700 nm and 136 − − 3000 K , respectively. The computed emission and absorption spectral profiles are based on the most recent potential energy curves and transition dipole moments. The required electronic Na ( 2 S ) + Ne ( 1 S ) and Na ( 2 P ) + Ne ( 1 S ) potentials are used from two different sets. Then the satellite structures in the blue wing are analysed quantum mechanically. The calculations show especially that the free–free transitions contribute most to the NaNe photoabsorption spectra and a satellite structure is observable beyond the temperature 402 K around the wavelengths 550 nm depending on the used potential set. The obtained results showed good agreement with those already published.

Experimental demonstration of a method to actively stabilize satellite structures against random perturbations of thermal boundary conditions using a closed-loop filter and controller approach

Modern space travel requires increasingly stable support structures for optical instruments or antennas, which can hardly be realized with the traditional approaches. Therefore, an approach for active structural stabilization of thermal-induced distortions was developed, simulated, and patented within the framework of the Infrared Astronomy Satellite Swarm Interferometry (IRASSI) project. Based on this approach, the thermomechanical transfer functions between the change in heat flux and the change in displacement of the finite-element (FE) model of a structure have already been validated in their basic functionality. In an experimental setup, the FE model was extended to include a closed-loop filter and controller approach consisting of a Kalman filter processing the temperature measurements in conjunction with a Linear Quadratic Regulator (LQR). It was shown that this setup can compensate for predefined sinusoidally oscillating disturbance heat flows, with an improvement of 4 dB compared to the uncontrolled case. In this paper, an experimental setup revised with respect to the positioning of the sensors and control heating elements, in conjunction with an extension of the filter and controller approach, will demonstrate that the system can respond to reproducible, random fluctuations in the disturbance heat flux, as well as stepped changes, and that performance has improved due to the revision.

Microvibration simulation of reaction wheel ball bearings

Microvibrations on board satellites are a well-known problem affecting their pointing accuracy by inducing oscillations to the line-of-sight. Fast rotating devices, such as reaction wheel assemblies (RWAs) are a major cause of these onboard mechanical disturbances. Imbalances in the flywheel, as well as imperfections in the ball-bearing components yield low-amplitude vibrations that are transmitted to the satellite structure, adversely affecting the performance of sensitive onboard instruments. This research focuses on the RWA’s ball bearing microvibration frequency and amplitude characterization. This is achieved by introducing specific geometry imperfections on the ball bearing rotating elements. In addition, variables such as the ball bearing preload, the number of balls and their dimensions are altered to understand how the bearing microvibration changes in order to minimize it. Finally, available physical microvibration test data is used to compare and cross-correlate the microvibration waterfall plots obtained from the transient FEA of the parametrized bearing models introduced herein. This work provides a better understanding of the relation between the main structural ball bearing parameters and the microvibration disturbances emitted by the RWA to minimize its mechanical noise.

A DIC method for thermal micro-deformation measurement of satellite high stability composite structure in simulated space environment

In order to ensure the stability and reliability of the entire satellite and onboard equipment indicators, the satellite highly stable structure can only produce small deformation or “near zero deformation” under the space on-orbit (thermal/vacuum) environment. The effective measurement and verification of its dimensional stability indicators directly determine the success or failure of the development of highly stable satellites. This work proposes a method for measuring the thermal deformation of highly stable satellite structures based on digital image correlation, (DIC), which designs a combined methodology of the digital image correlation measurement scheme, a measurement instrument protection method, a highly uniform temperature measurement and control system in the simulated space on-orbit thermal/vacuum environment. The methodology proposed in the work makes the digital image correlation measurement system suitable for space on-orbit measurement, and verifies that the measurement system can maintain high measurement accuracy. The research results indicate that this method can effectively solve the problems of measurement field interference, high uniform temperature control, speckle measurement camera, and measurement baseline protection. The thermal stability measurement experiment of a highly stable structure of a certain satellite has been successfully completed, and it has been verified that this method can meet the effectiveness and measurement accuracy of simulating thermal deformation measurement of structures in the simulated space on-orbit thermal environment.

Engineering the inter-island plasmonic coupling in homometallic Au-Aun core–satellite structures

Engineering the inter-island plasmonic coupling in homometallic Au-Aun core–satellite structures