Satellite Components Research Articles

Fast vibro-acoustic simulation methods of satellite components

PurposeThis paper aims to fast predict vibration responses of specific locations in the satellite subject to acoustic environment. It proposes a set of vibro-acoustic simulation methods of satellite components to represent their conditions in the whole satellite during the ground tests or launching. This study aims to use vibro-acoustic models of satellite components to replace that of hard modeling and time-consuming whole satellite when only local responses are concerned.Design/methodology/approachThis paper adopted experimental and numerical studies, with the latter based on the finite element (FE), statistical energy analysis (SEA) and FE-SEA hybrid theories. The vibro-acoustic model of the whole satellite was built and verified by experimental data. Based on the whole satellite model and experimental results, the fast vibro-acoustic simulation methods of all kinds of typical satellite components were discussed.FindingsThis paper shows that the models about satellite components not only show high consistency but also reduce 61.6% to 99.8% times compared with the whole satellite model. The recommended fast simulation methods for all kinds of typical satellite components were given in comprehensive consideration of the model accuracy, time required and response accessibility.Originality/valueThis paper fulfils an identified need to perform fast vibro-acoustic prediction of the local positions in satellites.

Analysis of the orbital evolution of space debris using a solar sail and natural forces

Since the launch of the first artificial satellite around the Earth up to the present date, various non-functional objects are orbiting the Earth, such as deactivated satellites, satellite components, rocket bodies, among others. These objects can collide with operational satellites or other debris, generating a cloud of smaller particles. Space agencies are concerned about the current scenario of the space environment. If we continue as we are the number of objects in orbit will make it difficult to operate safely in the space environment. So space exploration may become unsustainable (ESA (2020)). In this work, the orbital evolution of these objects that are located in the geostationary orbit (GEO) is analyzed. In the mathematical model we consider the main disturbing forces, such as the direct solar radiation pressure (SRP), the perturbation of the third body (Sun and Moon) and the Earth oblateness. The SRP is the most relevant perturbation for objects with larger area-mass ratio. Knowing this, the possibility of using a solar sail is considered to help to clean the space environment. The main natural environmental perturbations that act in the orbit of the debris are considered in the dynamics. Such forces acting in the solar sail can force the growth of the eccentricity of these objects in the GEO orbit. Several authors have presented models of the solar radiation pressure considering the single-averaged model. But, doing a literature research, we found that the authors consider the Earth around the Sun in a circular and inclined orbit. Our contribution to the SRP model is in developing a different approach from other authors, where we consider the Sun in an elliptical and inclined orbit, which is valid for other bodies in the solar system when the eccentricity cannot be neglected. The expression of the SRP is developed up to the second order. We found that the first-order term is much superior to the second-order term, so the quadrupole term can be neglected. Another contribution is the approach to identify the initial conditions of the perigee argument (g) and the longitude of the ascending node (h), where some values of the (g,h) plane contribute to amplify the eccentricity growth. In the numerical simulations we consider real data from space debris removed from the site Stuff in Space. The solar sail helps to clean up the space environment using a propulsion system that uses the Sun itself, a clean and abundant energy source, unlike chemical propellants, to contribute to the sustainability of space exploration.

A comprehensive review on space solar power satellite: an idiosyncratic approach.

Space solar power satellite (SSPS) is a prodigious energy system that collects and converts solar power to electric power in space, and then transmits the electric power to Earth wirelessly. The main principle of this system is to supply constant solar energy by placing collectors in geo-synchronous orbit and collecting it on an Earth-based receiver, known as a rectenna. This system can overcome serious drawbacks, especially the pseudo-random intermittent capacity factor of ground-based solar power or photovoltaic systems and modules. This paper discusses some old and new concepts of solar power satellite designs and the effects of various parameters on the efficiency of collecting medium, transmission media, and receivers' area. We evaluated and reviewed the three major components of the space-based satellite that have a hand in affecting the overall efficiency of the system, which are (1) collection unit, (2) power transmission unit, and (3) the receiving unit. This paper reviews the system as a whole, as proposed in the last three decades. Many of the microwave-based SSPS models that were proposed so far are based on solar concentrators. The required launch mass and system cost could be significantly reduced by using solar concentration and hence higher efficiency can be achieved. SSPS requires new microwave technology to achieve a high power conversion efficiency of over 80% and extremely accurate beam control from the 2km phased array transmitting antenna. Such specifications are extremely demanding and therefore significant effort is required for proper research and development. Under this technology roadmap, current research and development lead to the beginning of the new SSPS era in the coming decades.

Optimized deceleration characteristics of multicharged ion beams from electron cyclotron resonance ion source

At present it is necessary the satellite lifetime 10-15 years for operating in space. Xenon is used as fuel for ion engines of satellites. There are problems of accumulated damages at irradiation and sputtering by low energy Xe ion from the engine. It is required to construct database of sputtering yield of ion beams in the low energy region from a hundred eV to 1keV. We are trying to investigate experimentally sputtering yield on satellite component by irradiating the low energy Xe q+ ion beams. We use the electron cyclotron resonance ion source (ECRIS) in the irradiation experiments. We decelerate the beam energy to several hundred eV after extraction at high voltage 10kV. It is found we cannot neglect the contribution of the space potential of the plasma in the ECRIS of several tens eV. We measured the plasma parameters and ion beam deceleration characteristics in operating conditions on ECRIS. As the results, it was found in operating ECRIS condition of low charge state ion being dominant that the space potential of the ECRIS has an effect of 10∼20% at the beam energy at about 100eV in conducting irradiation experiments on satellite component materials.

Spectroscopic diagnostic of oscillating electric fields in edge plasmas

AbstractThe changes of plasma radiative properties in the presence of oscillating electric fields can be used for a diagnostic of the electric fields in the edge plasma. We present the modelling of hydrogen line shapes emitted in edge plasmas where powerful radio frequency (RF) waves are launched. RF waves are used for plasma heating and current drive, and understanding the details of their coupling to the plasma is an important issue in tokamak physics. Our model relies on a computer simulation of the plasma microfield and retains the emitter quantum evolution by solving numerically the Schrödinger equation. We calculate Lyman and Balmer lines of hydrogen in conditions where a significant part of the central intensity is transferred to satellite components under the simultaneous effects of the oscillating field and stochastic plasma microfield.

PERIOD – PERASPERA In-Orbit Demonstration toward the transition into the in-space services, assembly and manufacturing paradigm

Space robotics technologies are maturing, bringing new capabilities for In-orbit Services, Manufacturing and Assembly (ISMA). These capabilities will generate on-orbit services improving the orbital infrastructure, creating in turn a very promising business opportunity in terms of market volume. The establishment of a European capacity is necessary for building this new space infrastructure and to capture a fair part of this market. The concrete objectives of the PERIOD project are focusing on the main levers to generate the capabilities, which are the further maturation of the space robotics technologies and the definition of an in-orbit demonstration to be implemented as early as 2026. In the frame of the PERASPERA Strategic Research Cluster (SRC), key enabling products have been selected for technology maturation aiming at an increased technology readiness level (TRL). In support of the PERIOD activities, ESROCOS, ERGO and InFuse will be developed to TRL5 after an alignment of their perimeter to the demonstration objectives. The Standard Interconnects (SI), already at TRL5 at project start, will be tested in a benchmark for evaluating their performance. These SRC building blocks will be integrated in a breadboard at Airbus for supporting the system definition work. The PERIOD Consortium bringing together the competencies of Airbus Defence and Space, DFKI, EASN-TIS, GMV, ISISPACE, SENER Aerospacial and Space Application Services is proposing a very ambitious demonstration scenario and Factory concept. A satellite will be manufactured in an Orbital Factory to be designed in the study at SRR level and injected in LEO for operations. The manufacturing includes the fabrication of an antenna, the assembly of the satellite components and its reconfiguration and inspection in the Factory. Throughout the demonstration mission, the PERIOD facility will be upgraded to extend the level of capability validation from assembly and manufacturing of structures to attachment and refuelling experiments. Dissemination activities will maximize the impact of the project toward the Space Community. This demonstration covers the short and mid-to-long term ISMA business cases and will support the transition into the in-space services, assembly and manufacturing paradigm.

Functional Characterization of Replication-Associated Proteins Encoded by Alphasatellites Identified in Yunnan Province, China.

Alphasatellites, which encode only a replication-associated protein (alpha-Rep), are frequently found to be non-essential satellite components associated with begomovirus/betasatellite complexes, and their presence can modulate disease symptoms and/or viral DNA accumulation during infection. Our previous study has shown that there are three types of alphasatellites associated with begomovirus/betasatellite complexes in Yunnan province in China and they encode three corresponding types of alpha-Rep proteins. However, the biological functions of alpha-Reps remain poorly understood. In this study, we investigated the biological functions of alpha-Reps in post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) using 16c and 16-TGS transgenic Nicotiana benthamiana plants. Results showed that all the three types of alpha-Rep proteins were capable of suppressing the PTGS and reversing the TGS. Among them, the alpha-Rep of Y10DNA1 has the strongest PTGS and TGS suppressor activities. We also found that the alpha-Rep proteins were able to increase the accumulation of their helper virus during coinfection. These results suggest that the alpha-Reps may have a role in overcoming host defense, which provides a possible explanation for the selective advantage provided by the association of alphasatellites with begomovirus/betasatellite complexes.

Efficient Real-Time Tracking of Satellite Components Based on Frame Matching

In order to obtain the satellite’s in-orbit attitude information, it is necessary to track the satellite components in satellite video sequences. To solve the problem of low illumination and target occlusion in space environment, we propose an efficient satellite component tracking technique based on Rethinking Space-Time Networks with Improved Memory Coverage (STCN). We classify the pixels in the query frame by feature matching network that establishes the corresponding relationship between the frames. Unlike STCN, we reduce the contribution of background region in feature matching and enhance the robustness of the model in low illumination environment, thus improving the segmentation results. For lost targets due to the overturning and occlusion of satellite components, a position information encoder module is designed to further raise the tracking performance of the model. In addition, we present a local matching module to upgrade the existing feature matching methods. Experiments demonstrate that compared to STCN, our method heightens the tracking performance (J&F) by 10.1% and can achieve multi-object recognition at 15+ FPS.

The Great Slump: Mrk 926 reveals discrete and varying Balmer line satellite components during a drastic phase of decline

Aims.Mrk 926 is known to be a highly variable active galactic nucleus. Furthermore, it is known to show very broad line profiles. We intended to study the continuum and line profile variations of this object with high temporal resolution in order to determine its broad-line region structure and to derive its black hole mass.Methods.We carried out a high-cadence spectroscopic variability campaign of Mrk 926 with the 10m HET telescope, aided by photometricV-band data taken with the C18 telescope at the Wise Observatory, over a period of about five months. We extracted spectroscopic continuum and line light curves, and computed cross-correlation functions (CCFs) as well as velocity-resolved CCFs with respect to the combined spectroscopic and photometricV-band light curve.Results.The continuum luminosity of Mrk 926 showed a drastic decrease during our campaign. The luminosity dropped to less than 50% of its original luminosity within only 2.5 months. Furthermore, the spectra of Mrk 926 show complex and very broad Balmer line profiles, including outer Balmer satellites ranging from ±5000 to ±13 000 km s−1. The integrated Hα, Hβ, and He Iλ5876 line light curves are delayed relative to the continuum light curve. The Hαand Hβlines show two velocity-delay structures in the central part of their line profile (within ±5000 km s−1), at ∼10 and ∼57 light-days and at ∼5 and ∼48 light-days, respectively. These structures might be interpreted as the upper and lower halves of an ellipse in the velocity-delay plane, which might be the signature of a line-emitting ring, inclined by ∼50° to the line of sight and orbiting the black hole at radii,R, of 33.5 and 26.5 light-days. We determined continuum luminosities, log(λ Lλ/erg s−1), of 43.68–44.13, which are in good agreement with the establishedRBLR − LAGNrelation. Adopting delays of 33.5 and 26.5 days for Hαand Hβ, respectively, we derive a black hole mass of (1.1 ± 0.2)×108 M⊙; this indicates a low Eddington ratio, which decreased from 8 to 3 percent during our campaign. The Balmer satellite components show a higher correlation coefficient with respect to the continuum than the central line profile, and their response to the continuum variations is on the order of only 3 − 5 days. We attribute this to the central line segment and the Balmer satellites having different, spatially distinct regions of origin.

Small Satellite Operational Phase Thermal Analysis and Design: A Comparative Study

This paper is about the modeling and design of the passive thermal control system for the European Student Earth Orbiter (ESEO) satellite. A detailed thermal model was created in Thermal Desktop software. The model was running for the operative phase which includes cycles of 28 orbits. During these 28 orbits, there are several modes (10 modes). Each mode has a specific duration, attitude (Sun-nadir), and certain internal heat dissipation. The design of the passive thermal control system was based on controlling the conductive and radiative heat exchange between the internal components and the mounting panels, between panels themselves, and controlling external radiation exchange to achieve the desired components temperature ranges. The temperature results from simulations were presented to show the expected component temperatures and to demonstrate that the passive thermal control system met the requirements of the temperature limits. The final passive thermal control design shows that the satellite components temperatures were always maintained within their required limits during the operational phase

Function of Centriolar Satellites and Regulation by Post-Translational Modifications.

Centriolar satellites are small membrane-less granules that gravitate around the centrosome. Recent advances in defining the satellite proteome and interactome have unveiled hundreds of new satellite components thus illustrating the complex nature of these particles. Although initially linked to the homeostasis of centrosome and the formation of primary cilia, these composite and highly dynamic structures appear to participate in additional cellular processes, such as proteostasis, autophagy, and cellular stress. In this review, we first outline the main features and many roles of centriolar satellites. We then discuss how post-translational modifications, such as phosphorylation and ubiquitination, shape their composition and functions. This is of particular interest as interfering with these processes may provide ways to manipulate these structures.

A multiplex polymerase chain reaction for the simultaneous detection of the virus and satellite components associated with cotton leaf curl begomovirus disease complex

Cotton leaf curl disease (CLCuD) is caused by a complex of several whiteflies (Bemisia tabaci Genn.)-transmitted begomovirus species, Cotton leaf curl Multan virus (CLCuMuV), Cotton leaf curl Kokhran virus (CLCuKoV) and Cotton leaf curl Alabad virus (CLCuAlV) by individual of mixed infection, associated with Cotton leaf curl Multan betasatellite (CLCuMB) and several alphasatellites. The disease causes major economic losses in cotton in the Indian subcontinent. For monitoring of epidemiology and development of management strategies of CLCuD, a quick, sensitive and effective method capable of detecting all the begomovirus, betasatellite and alphasatellite components associated with CLCuD is required. With this objective, a multiplex polymerase chain reaction (mPCR) assay was developed for the simultaneous detection of these three viral components associated with CLCuD of cotton. Primers for each component were designed based on the retrieved reference sequences from the GenBank. Each pair of primers, designed for each of the respective component, was evaluated for its sensitivity and specificity in both the component-specific simplex polymerase chain reaction (sPCR) and mPCR assay. This report identified three viral component-specific pairs of primers which, in all combinations, amplified simultaneously the CP gene (780 nts) of the begomovirus, the βC1gene (375 nts) of the betasatellite and the Rep gene (452 nts) of the alphasatellite associated with CLCuD in the mPCR assays. The amplified products specific to each component produced by these assays were identified based on their amplicon sizes, and the identities of the viral components amplified were confirmed by cloning and sequencing the amplicons obtained in the mPCR. The mPCR assay was validated using naturally CLCuD-affected cotton plants of the fields. This assay will be useful for rapid detection of CLCuD-associated begomovirus, betasatellite and alphasatellite DNA in field samples, extensive resistance screening in resistance breeding programme, and also monitoring epidemiology for detection of virus and its components when symptoms are mild or absent in the plant.

Space Radiation of Solar Storm: A Meeting Report in Taiwan

Solar storm was an effect when Sun was active. Solar flares flame released a large amount of energy and caused a large-scale explosion. A large amount of coronal matter was ejected into space by plasma composed of electrons and protons. Their shock waves or magnetic clouds and the earth Magnetic storms generated by the interaction of magnetic fields caused disturbances and squeezing of the earth’s magnetosphere. A solar flare was a phenomenon of solar storm. It had huge eruptions of electromagnetic radiation. The sudden electromagnetic energy traveled with the speed of light. Large solar flare might affect the effects of reliability of electronic components in satellites and could cause economic losses by soft error and could affect human health through the space radiation, especially causing cancer.

Satellite forward VDES channel modeling and impact on higher‐layer performance

SummaryVHF data exchange system (VDES) is an emerging maritime communications standard that is meant to provide ship‐to‐shore, shore‐to‐ship, and ship‐to‐ship information services. VDES also includes a satellite component to extend the service coverage also to the high sea. Ships can receive important information via VDES and access this service via satellite when they are far from the shore. This paper uses data taken during a measurement campaign to develop an ON‐OFF model for the VDE‐SAT downlink channel taking the multipath effects caused by sea reflections into account. This model has been used to evaluate the impact of packet‐level forward error correction (FEC) schemes (i.e., ideal codes, RaptorQ codes, and 2‐Dimension Reed‐Solomon codes) to further protect transmissions from deep fading events and to evaluate the impact at the transport level considering the possibility to adopt the transmission control protocol (TCP) for a file map delivery service.

Performance bounds for VDE‐SAT R‐Mode

SummaryThere has been growing interest within the satellite navigation community in the possibility of delivering positioning and timing services from existing or emerging constellations of Low‐Earth Orbit communication satellites. At the same time, the international maritime community has been investigating the potential use of communication signals transmitted from shore‐based stations for positioning—a concept commonly referred to as ‘ranging mode’, or R‐Mode. The driving force for these developments is the desire to reduce the reliance on traditional Global Navigation Satellite Systems (GNSS). One of the technologies being considered for use in R‐Mode is the evolution of the Automatic Identification System (AIS) known as the Very High Frequency Data Exchange System (VDES). VDES has a terrestrial and a satellite component. The feasibility of using terrestrial VDES transmissions for ranging was studied in a previous publication by the authors. This paper builds on the previous study and extends its results to the satellite component of VDES. Statistical bounds on the ranging error are derived for all downlink waveforms currently being considered for use in satellite VDES and for several custom‐designed transmission formats. The analysis supports the feasibility of using both the existing and custom waveforms in ranging applications and points to related trade‐offs that will need to be considered in the design of satellite VDES R‐Mode systems.

A simple numerical model for the variation of cubesat temperature along its orbit

A simple model for the variation of CubeSat temperature along its orbit is presented. First, an analytic solution for the satellite temperature variation with time when subjected to a bistable heat source: two segments with piece-wise constant power, such as orbits with an eclipsed segment when the Sun is not directly visible, is considered. The model assumes that at a given time a single temperature applies to the entire satellite body. Discussion is focused on CubeSat satellites in low-Earth orbits, the uncertainties in predicted temperatures due to uncertain input parameters, and it emphasizes the importance of the satellite thermal inertia in setting the amplitude of the temperature variation along the orbit. This simplified “spherical cow" model is suitable for studying the relative effects of surfaces with different emissivities, the effects of small changes in the solar flux between June and December, the impact of thermal inertia, and as a “sanity check" for the results obtained with numerical thermal models that utilize detailed geometrical and thermal descriptions of all satellite components. It was found that the mean satellite temperature depends on the extreme values of steady-state equilibrium temperatures for eclipsed and non-eclipsed parts of the orbit, and the duration of the eclipse relative to the orbital period; in contrast, the amplitude of temperature variation around the mean temperature is by and large controlled by the satellite thermal inertia. A numerical model with arbitrary time dependence of the heating power is also developed, including its dependence on the satellite temperature, and validated it using analytic solution for a bistable heat source. Analysis of a typical 2U CubeSat shows that low temperatures are more worrisome than high temperatures, and that low temperatures can be mitigated by active temperature control such as releasing heat when the satellite is in eclipse using electrical energy stored in batteries that are charged during non-eclipsed portion of the orbit.

Space environment effects on equipment and structures—current and future technologies

The space environment is extremely hostile to the spacecraft but also to the equipment it carries. The materials which are used to the external side of the spacecraft, the solar panels, the sensors, and the electronics circuits, suffer greatly from their exposure to it. Extreme temperatures, ultraviolet radiation, ionizing radiation from solar proton events and cosmic rays, atomic oxygen in LEO, as well as collisions with micrometeoroids and space debris are factors that degrade the stuff, multiply the mission cost, and increase the risk. Therefore, the state-of-art of material technology is needed. In this study, a set of materials and technologies are presented, which reduce the above-mentioned risks. Extreme temperatures, ultra-vacuum, atomic oxygen, and high-energy radiation including particles as well as energy sources (X- and gamma rays) are potential extreme exposure conditions. Testing and qualification of materials exposed to these extreme conditions is a difficult task, to enable the design and manufacturing of high-endurance reliable components to be used in the world’s most sophisticated satellite and spacecraft components, as well as in future endeavors into the vicinity of the Solar System.

Mechanical and Chemical Characterisation of TiN and AlTiSiN Coatings on a LPBF Processed IN718 Substrate.

Wear-resistant coatings development is progressively increasing steeply due to their advantages when applied to mechanical components subjected to abrasive and destructive environments. Titanium nitride (TiN) coating is typically used to enlarge tools and components’ service life and improve their surface quality. On the other hand, AlTiSiN coating intends to be applied to more aggressive environments such as spatial satellites components exposed to solar radiation, extremely high temperatures, and random particles impact. In this work, specimens of Inconel 718 (IN718) were fabricated via laser powder bed fusion (LPBF), and physical vapour deposition (PVD)-deposited with TiN and AlTiSiN as coatings to mechanically and chemically characterise their surface. In this respect, microhardness testing and chemical analysis via glow discharge optical emission spectroscopy (GDOES) were performed. Later, roughness and wear behaviour analyses were carried out to evaluate the mechanical performance of both coatings and their surface and morphological features. The experimental observations allowed the analysis of both studied coatings by comparing them with the substrate processed via LPBF.

Bearing Fault Detection Using DWT and CNN

Bearing is a key component of satellite inertia actuators such as moment wheel assemblies (MWAs) and control moment gyros (CMGs), and its operating state is directly related to the performance and service life of satellites. However, because of the complexity of the vibration frequency components of satellite bearing assemblies and the small loading, normal running bearings normally present similar fault characteristics in long-term ground life experiments, which makes it difficult to judge the bearing fault status. There are various methods introduced for condition monitoring such as vibration analysis, temperature analysis, wear and debris analysis, image processing etc. Among this image analysis is found to be the most effective method for detection of machine faults. This paper proposes an automatic fault diagnosis method for bearings based on a DWT and CNN.

Role of chemical vs. physical interfacial interaction and adsorbed water on the tribology of ultrathin 2D-material/steel interfaces

Lubrication of steel using two-dimensional (2D)-materials has been a growing interest in recent years at the macro/microscale for a wide range of applications including lubricating 440 C-steel for satellite and automotive components. This work takes a new approach of comparing the tribological behavior of ultrathin-graphite and ultrathin-MoS2 at varying humidity against a custom-fabricated 440 C-steel counter-surface using friction force microscopy. The presence of oxides on the 440 C-steel counter-surface is found to form stronger chemical interactions with MoS2, leading to higher friction, interfacial-shear-strength and adhesion as compared to physically interacting steel/ultrathin-graphite interface. While water increases friction and adhesion for steel/ultrathin-graphite interface, an opposite trend is observed for steel/MoS2 interface, where water act as a temporary protective film to suppress the chemical interaction.