Satellite Engineering Research Articles

APPLICATION OF KEPLER'S LAWS IN PHYSICS

Kepler’s laws of planetary motion provide fundamental insights into the mechanics of celestial bodies. These laws are crucial in understanding orbital mechanics, which play a significant role in modern astrophysics, satellite engineering, and space exploration. This paper presents a comprehensive exploration of the application of Kepler's laws in physics, emphasizing their relevance to both historical and contemporary scientific advancements. The study evaluates the laws' contributions to Newtonian mechanics and modern applications in satellite technology and gravitational theory.

Analysis of the calculation method and evaluation of the magnetic acceleration noise of space inertial sensor

Accurately calculating the magnetic acceleration noise is essential to designing the space inertial sensor and constructing its evaluation system. In view of the shortcomings of the magnetic acceleration noise calculation model, which considers the test mass (TM) as an ideal magnetic dipole rather than an entity, the Maxwell stress tensor method (MSTM) and virtual work principle method (VWPM), which consider the influence of the shape and size of the TM into account are adopted in this study. Through comparison, it is concluded that the non-uniformities of the internal magnetic field and magnetization intensity of the TM are the reasons for the calculation error of the model, and when the magnetic susceptibility is <1 × 10−2, the model can satisfy the requirement of the calculation accuracy. Finally, two specific signals of the near-interplanetary magnetic field and the magnetic field of a circuit board were measured in a magnetic shielding room (MSR), and the magnetic acceleration noises induced by the two magnetic environments were calculated. These can act as significant reference values for magnetic acceleration noise experiments in orbit and the layout of electronic devices in satellite engineering.

Physics-informed deep Monte Carlo quantile regression method for interval multilevel Bayesian Network-based satellite circuit board reliability analysis

Temperature field reconstruction is essential for analyzing the reliability of a high-density functionally integrated satellite circuit board (HFI-SCB). As a representative deep learning model, the deep convolutional neural network (DCNN) is a powerful tool for reconstructing the HFI-SCB temperature field. However, DCNN needs a lot of labeled data to learn its parameters, which is contrary to the fact that actual satellite engineering can only acquire noisy unlabeled data. Thus, this paper proposes an unsupervised method, i.e., the physics-informed deep Monte Carlo quantile regression method, for reconstructing the HFI-SCB temperature field and quantifying the data uncertainty caused by sensor noise. The proposed method combines a DCNN with known physics knowledge to reconstruct an accurate HFI-SCB temperature field using only monitoring point temperatures. Besides, the proposed method can quantify the data uncertainty by the Monte Carlo quantile regression. Based on the reconstructed temperature field and the quantified data uncertainty, this paper builds an interval multilevel Bayesian Network to analyze the HFI-SCB reliability. Two case studies are used to validate the proposed method.

Hierarchical Model Updating Method for Vector Electric-Propulsion Satellites

Electric propulsion is of great significance to the development of high-efficiency and long-life satellites, and digital twins have gradually become a powerful tool for satellite engineering. Being affected by uncertainty factors such as the complexity and variability of the space environment and the satellite system, the digital twin model cannot accurately reflect the real physical properties. Therefore, it is crucial to update the satellite model to improve prediction accuracy. However, the complex structure and multi-physics process coupling of vector electric-propulsion satellites bring great challenges to model updating. According to the characteristics of the vector electric-propulsion satellite, this paper establishes mathematical models of the whole satellite. Additionally, a hierarchical model updating method is proposed and applied to the model updating case of a satellite with multiple subsystems. The simulation results show that the method is suitable for the model updating of the vector electric-propulsion satellite. Through multiple iterations of closed-loop cycles, the residual errors between the simulation values and the telemetry values can be decreased, and the errors between the estimated values and the true values of state variables can also be decreased by an order of magnitude.

Cost Model for CubeSat Projects in Mexico

This work focused on designing a cost estimation model in the area of space engineering for the development of nanosatellite projects in Mexico. See employed the use of methodologies such as Hall and Jenkins, software engineering cost estimating methodology, as well as project management methodology. Similarly, the COSYSMO methodology and parametric cost methodology were incorporated to guide this research towards the space sector. The estimation results are based on satellite engineering equations and forecasts of the inflation factor. Finally, a graphical user interface named SACANI was obtained. Allowing the estimating a nanosatellite project by ”integration of components” or by ”research and development”. The first asks the user for the components by subsystem through drop-down lists, giving a breakdown of the estimated costs for the CubeSat, development phases and ground station, according to the data provided by the interested party. The second model is more robust because it requests the type of project, the category, the amount of CubeSat required, the year to estimate the cost, the mass of the payload, among other data. Similarly, both models yield a previous result of the estimate made according to the data entered by the project estimator.

The Third China International Synthetic Aperture Radar Symposium [Conference Reports

From 2 to 4 November 2022, the third China International Synthetic Aperture Radar (SAR) Symposium (CISS), sponsored by the Shanghai Institute of Satellite Engineering, was successfully held at the Jinjiang Metropolo Hotel Minhang, Shanghai. The CISS is an international academic conference with extensive authority, knowledge, and interaction. The symposium aims to build a high-level and international academic communication platform for scholars and researchers in the SAR field, lead the direction of technology development in the SAR field, and promote technology innovation in related fields. CISS 2022 was technically cosponsored by IEEE and the IEEE Geoscience and Remote Sensing Society (GRSS). More than 180 invited experts and scholars from China, Germany, New Zealand, Poland, and other countries assembled to discuss the latest developments and achievements in SAR-related areas, including hardware systems, processing techniques, advanced applications, and so on. CISS 2022 was held online and offline, and more than 150 participants attended offline live events. Nine experts ( <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> ) gave keynotes during the opening ceremony. During the conference, 72 researchers presented their work in oral form, while 94 reports were presented in poster form.

Overlapping-calibration of wide-swath altimeter baseline errors using two satellites formation flying design

The sea surface height (SSH) measured by future wide-swath altimetry satellites contains observation error due to baseline measurement, which is called SSH_Error_Baseline. It is a huge challenge for satellite engineering to maintain such high accuracies of the baseline roll and length in orbit to ensure that the SSH_Error_Baseline can be maintained below 1 cm. Therefore, how to effectively reduce the SSH_Error_Baseline is extremely important. In order to solve the existing problem, an innovative overlapping-calibration method is proposed based on two-satellite formation flight design with overlapping swath. In this study, the differences of SSH data observed by these two satellites in the overlapping area is so small that it can be ignored, and the SSH_Error_Baseline dominates the difference. Then, the baseline parameters of the two satellites can be well estimated by adopting an optimal inverse method. A total of 9 groups of observing system simulation experiments (OSSEs) have been carried out, and they respectively indicate different pessimistic theoretical scenarios of baseline measurement systems. According to the results, this design can effectively reduce the SSH_Error_Baseline in most scenarios. Regarding the advantage of this method, it can be applied to all along-track observation data without requiring the application of additional auxiliary data (i.e. model data, SSH derived from nadir altimetry). Therefore, when two wide-swath altimetry satellites are simultaneously designed, the formation flight scheme proposed in this paper is recommended, especially when the measurements of the baseline cannot meet the expected accuracies.

GTOC 11: Results from Tsinghua University and Shanghai Institute of Satellite Engineering

In this paper, the methods and results from Tsinghua University and Shanghai Institute of Satellite Engineering for the 11th Global Trajectory Optimization Competition (GTOC11) are presented. To deal with the complicated “Dyson Sphere” building problem, a three-stage procedure is conducted. First, the pre-analysis is performed to reduce search space. It is found that two-impulse maneuvers between asteroid flybys are near-optimal, the semi-major axis of the “Dyson Ring” should be better at 1.0–1.5 AU, and the larger arrival mass asteroids tend to be selected. Second, the globally optimal trajectory design problem is further divided into two sub-problems, the mothership trajectory design and the asteroid assignment to the “Dyson Ring” power stations. For the first problem, beam search is used to obtain numerous single mothership trajectories based on a pre-constructed flyby trajectory database of 3–8 asteroids. The overall trajectories and asteroids visited are obtained by selecting 10 mothership trajectories with a genetic algorithm. For the second problem, we build a database of optimal rendezvous times for all the 83,453 asteroids at different phase angles to reach power stations of different radii and phase angles, then a greedy algorithm is proposed to obtain the asteroid arrival schedule based on all the asteroids visited by motherships. Finally, local optimization of asteroid sequence and flyby epochs is conducted. The activation time adjustment in combination with indirect continuous-thrust trajectory optimization is used based on the global optimization result. In the final submission, motherships fly by 388 asteroids, and the minimum mass of twelve power stations reaches 94% of the theoretical upper bound, which is defined using the minimum-time orbital transfers with free initial and target phases.

Optimal periodic switching strategy for a two‐unit warm standby degradation system

AbstractIn the traditional switching policy of a standby system, the standby unit is switched to the normal operation state only after the active unit fails. In contrast, in satellite engineering, a new periodic switching strategy is used by technicians in the satellite gyroscope standby system. Due to the performance degradation of the gyroscope in the long‐term operation and standby process, satellites may fail on orbit. For this problem, an operation optimization model is established for a two‐unit warm standby degradation system considering the periodic switching strategy. First, the degradation process of the units is described by a multiphase Wiener process. Second, based on the first‐hitting time theory, the analytic expressions of reliability and mean time to failure (MTTF) of the degradation system are derived. Third, the optimal periodic switching interval is determined to maximize the system MTTF by using the particle swarm optimization algorithm (PSO). Finally, a numerical example of a gyroscope warm standby subsystem is provided to validate the proposed model.

Rapid search method for a spacecraft attitude maneuver path with multiple constraints

The rapid attitude maneuver capability of spacecraft is required in many space missions. Due to the complex attitude constraints and limited satellite resources, the rapid on-orbit attitude maneuver is very challenging for spacecraft attitude control systems. To address this problem, a rapid attitude path search method named Constraint Path Mapping (CPM) is proposed to quickly obtain a safe attitude path. In the CPM method, the attitude constraint safety-mapping strategy is designed to map the attitude constraint space to the attitude safety space, allowing for efficient planning and improved processing of complex attitude constraints. For resource use, this paper adopts the Euler forward search and node safety search to avoid algorithm redundancy caused by the repeated processing of the constraints. Finally, the numerical simulation is performed to validate the feasibility and effectiveness of the proposed method. In particular, this method is expected to be tested on a reconnaissance satellite launched by the Shanghai Institute of Satellite Engineering in March 2021.

A sequential multi-prior integration and updating method for complex multi-level system based on Bayesian melding method

In engineering, there exist multiple priors about system and subsystems uncertainties, which should be integrated properly to analyze the system reliability. In the past research, an iterative updating procedure based on Bayesian Melding Method (I-BMM) was developed to merge and update multiple priors for the double-level system. However, the in-depth study in this paper shows that the original iterative procedure has no effect on the prior updating. Thus it is proposed that only a single BMM iteration process is needed following the original prior integration and updating formulation. BMM involves the sampling procedure for the probability density function (PDF) updating, wherein it is generally difficult to define the sampling number properly for obtaining accurate priors. To address this problem, a sequential prior integration and updating framework based on the original single BMM iteration process (S-BMM) is developed in this paper. In each cycle of prior updating, the sample number is sequentially added, and the difference between prior distributions obtained in the two consecutive cycles is measured with the symmetric Kullback-Leibler Divergence (SKLD). The sequential procedure is continued until the convergence to the accurate updated prior. The S-BMM framework for double-level systems is further extended for multi-level systems. Situations with some missing subsystem or component priors are also discussed. Finally, two numerical examples and one satellite engineering case are used to demonstrate and verify the proposed algorithms.

Attitude Control of Microsatellite Using PWM Method: Verification Using PIL

The missions of micro-satellites range from early military usages to weather forecast, resources exploration, communication, and scientific experiment. The advantages of micro-satellites are simple mechanical structures, great reliability, low prices, and precise researchers and equipment. Therefore, due to the limits of weight and power, this kind of micro-satellite with low design cost and high precision requires reducing unnecessary attitude sensors and controllers to ensure the precision of attitude control. Besides, it adapts the least hardware constituting attitude system, which is the future trend in the satellite engineering. In this article, an estimating technology about measuring angle speed with a gyro less is mentioned. This technology is based on the period change which the earth magnetic field gets along the track. Only by using a three axis magnetometer, it can produce the data from the micro-satellite measuring the earth magnetic field. Besides, the measures of three axis angle speed and attitude angle can be gotten through Kalman filtering. The purpose of this article is mainly to explore the problem on attitude detumbling control of micro-satellites departing away a carrier to enter a track. It is realized by a thruster to proceed the confinement of the satellite moving, the attitude stable control and processor-in-the-loop.

TH-2 satellite engineering design and implementation

TH-2 satellite engineering design and implementation

Fuzzy PD hybrid control of low frequency vibration of annular antenna

The annular antenna is a typical large flexible space truss structure featured by small damping and low modal frequencies. The external disturbances, e.g. impulse load resulting from satellite attitude adjusting, may induce the low frequency large amplitude vibrations of annular antenna for a long time and thus reduce working precision and cause even its damage. The active control of vibration of annular antenna under impulse excitation is investigated in the paper. The voice coil actuator instead of piezoelectric stack actuator is used in order to meet the demand of large output displacement. The governing equation of active vibration control system is established by use of finite element method. The proportional differential (PD) control and fuzzy control algorithms are firstly studied in the active control. The results show that the fuzzy control exhibits worse control performance than PD control due to weak control function near structural equilibrium position. To circumvent the drawback of fuzzy control, a fuzzy PD hybrid control strategy is proposed which can combine the merits of both control methods. The simulated and experimental results show that the fuzzy PD hybrid control can yield the best control effect under impulse excitation comparing with the PD control and ordinary fuzzy control. The work provides a promising control way for active control of low frequency and large displacement vibration of annular antenna in satellite engineering.

NASRDA’s Experience in Human Capacity Development and Capability Accumulation in Satellite Technology

The National Space Research & Development Agency (NASRDA) was created in 1999 to coordinate and oversee all space activities for Nigeria. With little or no human space technology capacity and capability at inception, the agency embarked on an aggressive human capacity building and accumulation mission. From its creation, the agency has been strongly committed to achieving independent satellite development capability. As the agency celebrates its 20 years of existence in 2019, it has emerged as one of the largest space institutions in the African continent - launching five successful satellites of various sizes, all of which involved technology transfers to Nigerian scientists and engineers. NigeriaSat-2 and NigeriaSat-X were two medium Earth Observation satellites launched in 2011 to provide medium resolution imagery to serve the needs of various institutions not only within Nigeria, but also other nations through a constellation of satellites managed by the DMCii, UK. While NigeriaSat-2 was procured from SSTL, NigeriaSat-X served as a training model through which satellite engineering design skills were transferred to Nigerian Engineers from SSTL, UK. Six years after the launch of NigeriSat-2 and Nigerisat-X, a cubesat dubbed “NigeriEduSat-1” was launched from a university-to-university (U2U) collaboration between FUTA, Akure and KIT, Japan. The U2U collaboration, facilitated by National Space Research & Development Agency, was aimed at improving technology absorption and local diffusion of satellite engineering within the country. This paper reviews strides made by NASRDA in accumulating know-how satellite development and further discusses the various efforts made in building its first satellite independently.

Knowledge Management Via AUTomated Organizational CARTography (AUTOCART)

The post-globalization epoch has placed businesses everywhere in new and different competitive situations where knowledgeable, effective, and efficient behavior has come to provide the competitive and comparative edge. In this paper, we propose a model to automatically acquire, visually represent, and collectively reason on organizational textual content. The model enables an organization to visualize its knowledge and knowledge flows and present them in a graphical and visual framework, referred to as AUTomated Organizational CARTography (AUTOCART). Applying this model in the area of satellite engineering, we conduct an empirical study to explore the process of knowledge acquisition and diffusion in organizations. We find that text-based knowledge diffusion may be the solution to alleviating knowledge bottlenecks and there exists cohesion between scientific and commercial research based on the practice adopted within an organization. Our research provides great insights for practitioners to effectively manage knowledge assets in organizations.

An Engineering Project Management System Design of Fengyun Meteorological Satellite

Fengyun Meteorological Satellite Engineering System has the characteristics of long construction period, huge investment, and complicated user roles involved in the project, and accumulated data and documents during project construction. In order to coordinate the management of the system and improve management efficiency, this article has designed Fengyun satellite engineering project management system. The design includes the system framework, key technologies and module functions. Through the design of this system, Fengyun satellite engineering system management is more simple and efficient.

A coordination method for concurrent design and a collaboration tool for parametric system models

This work presents a method and a tool for conducting conceptual design studies for projects such as a space exploration mission and a satellite constellation in a concurrent manner in both time and space, while taking into account the structure of the system to design and the dependencies between the system’s constituting elements. Design work is parallelized to reduce the time required to converge to a solution for a preliminary design, which includes the system architecture, its detailed requirements, and its costs. The multidisciplinary team of designers works in colocation to leverage effective direct human interaction for discussing design trade-offs quickly. While this is practice in space agencies for mission feasibility studies, a common methodology was not described so far. Our work proposes a method for the coordination of discipline experts and the sequence of activities performed during conceptual design studies, which use integrated parametric system models. Our method reduces the number of design iterations by applying a design structure matrix clustering algorithm to the system model and deriving a schedule for the design session. We also describe the tool Concurrent Engineering Data Exchange Skoltech we developed for collaborative work on the parametric system models and serve as an instrument for research on complex system design methodologies. The tool features a fast synchronization mechanism for the concurrent work of multiple design experts, and it supports our coordination method for concurrent design studies. The tool was published as open-source software, so other researchers can use it and build upon it. We used our tool and applied the method to two case studies of preliminary satellite designs and tested them with groups of students of a satellite engineering class and researchers from our institute. Throughout the experiments, we recorded information about user interactions and collected user feedback for the evaluation of the coordination method and the collaboration tool. Both method and tool demonstrated their validity in our experimental setting.

Thermal Effect on Vibration of Tapered Rectangular Plate

A mathematical model is constructed to help the engineers in designing various mechanical structures mostly used in satellite and aeronautical engineering. In the present model, vibration of rectangular plate with nonuniform thickness is discussed. Temperature variations are considered biparabolic, that is, parabolic in x-direction and parabolic in y-direction. The fourth-order differential equation of the motion is solved by Rayleigh Ritz method for three different boundary conditions around the boundary of plate. Numerical values of frequencies for the first two modes of vibration are presented in tabular form for different values of thermal gradient, taper constants, and aspect ratio.

Robust Satellite Engineering in Educational Cubesat Missions at the Example of the UWE-3 Project

With the introduction of the cubesat standard hands-on satellite engineering received a significant boost at educational university programs. However, not all missions could demonstrate successful operation in orbit. Besides technical challenges due to the extremely limited mass and volume imposed by the standard, cubesat projects at university level typically inhere challenges due to high student fluctuation together with significant launch delays and limited financial budgets. In order to ensure feasibility and continuity over long time, special care in the engineering process, especially design, production, integration and testing, has to be taken. This contribution gives an overview about tools and procedures developed in the context of the University of Wuerzburgs UWE project, which support robust satellite engineering despite mentioned challenges.