Development Of Space Technology Research Articles

Scheduling of Earth observing satellites using distributed constraint optimization

AbstractEarth observation satellites (EOS) are satellites equipped with optical sensors that orbit the Earth to take photographs of particular areas at the request of users. With the development of space technology, the number of satellites has increased continuously. Yet still, the number of satellites cannot meet the explosive growth of applications. Thus, scheduling solutions are required to satisfy requests and obtain high observation efficiency. While the literature on multi-satellite scheduling is rich, most solutions are centralized algorithms. However, due to their cost, EOS systems are often co-funded by several agents (e.g., countries, companies, or research institutes). Central solutions require that these agents share their requests for observations with others. To date, there has yet to be a solution for EOS scheduling that protects the private information of the interested parties. In this study, we model the EOS scheduling problem as a distributed constraint optimization problem (DCOP). This modeling enables the generation of timetables for the satellites in a distributed manner without a priori sharing users’ private information with some central authority. For solving the resulting DCOP, we use and compare the results of two different local search algorithms—Distributed Stochastic Algorithm and Maximum Gain Message—which are known to produce efficient solutions in a timely manner. The modeling and solving of the resulting DCOP constitute our new solution method, which we term Distributed Satellite Timetable Solver (DSTS). Experimental evaluation reveals that the DSTS method provides solutions of higher quality than a commonly used centralized greedy algorithm and is comparable to an additional centralized algorithm that we propose.

Operational Tests for Delay-Tolerant Network between the Moon and Earth Using the Korea Pathfinder Lunar Orbiter in Lunar Orbit

The Korea Pathfinder Lunar Orbiter (KPLO) was launched on 5 August 2022, equipped on the SpaceX Falcon 9 launch vehicle. At present, the KPLO is effectively carrying out its scientific mission in lunar orbit. The KPLO serves as a cornerstone for the development and validation of Korean space science and deep space technology. Among its payloads is the DTNPL, enabling the first-ever test of delay-tolerant network (DTN) technology for satellites in lunar orbit. DTN technology represents a significant advancement in space communication, offering stable communication capabilities characterized by high delay tolerance, reliability, and asymmetric communication speeds—a necessity for existing satellite and space communication systems to evolve. In this paper, we briefly give an overview of the Korea Lunar Exploration Program (KLEP) and present scientific data gathered through the KPLO mission. Specifically, we focus on the operational tests for DTN-ION conducted for message and file transfer, as well as real-time video streaming, during the initial operations of the KPLO. Lastly, this study offers insights and lessons learned from KPLO DTNPL operations, with the goal of providing valuable guidance for future advancements in space communication.

Structural design and surface networking analysis of a truss antenna based on hexagonal frustum deployable mechanism units

With the development of space technology, deployable mechanism has been widely applied in large aperture space antennas. In this paper, a hexagonal frustum deployable antenna unit and an innovative modular assembling concept are proposed for large parabolic truss antenna. Screw topology diagram and screw constraint matrix are established to solve degree of freedom (DOF) of the antenna mechanism. By separating column vectors of screw constraint matrix, whole actuations of antenna mechanism are obtained according to unique solution condition. A new hexagon antenna network method based on hexagon frustum units and rotation transformation matrix is proposed, and correctness and efficiency of the modeling principle are proved by simulation. Finally, a prototype of the proposed hexagonal frustum truss deployable antenna mechanism is constructed, and a deployment experiment is conducted, which demonstrate the mobility and deployment performance of the mechanism. The mechanism proposed in this paper provides a theoretical reference for the parabolic truss deployable antenna mechanism, which is potentially valuable in the application of large aperture deployable antennas.

Нелинейная радиофизика межзвездных перелетов: разгон макрообъектов с помощью электромагнитного излучения

We discusses one of the implementations of acceleration, based on powerful artificial radiation, of spacecraft capable of reaching the nearest stars in the constellation Alpha Centauri in twenty to thirty years (i.e., during the active life of one generation of people). The Breakthrough Starshot project (BS, Breakthrough: Starshot) was proposed in 2016. The key new aspects of the project are: 1) the idea of interstellar vehicles of ultra-small dimension, which makes the physical parameters of the project potentially achievable in the foreseeable future; 2) modular construction of the launch system and 3) extension of Moore's law to the development of space technology. As an alternative to the linear “BS” type scheme, a closed ring scheme for laser acceleration of macro-objects is considered below. It is shown to be promising for dramatically reducing the peak requirements for a linear-type micro spacecraft launch.

Discriminating Spectral-Spatial Feature Extraction for Hyperspectral Image Classification: A Review.

Hyperspectral images (HSIs) contain subtle spectral details and rich spatial contextures of land cover that benefit from developments in spectral imaging and space technology. The classification of HSIs, which aims to allocate an optimal label for each pixel, has broad prospects in the field of remote sensing. However, due to the redundancy between bands and complex spatial structures, the effectiveness of the shallow spectral-spatial features extracted by traditional machine-learning-based methods tends to be unsatisfying. Over recent decades, various methods based on deep learning in the field of computer vision have been proposed to allow for the discrimination of spectral-spatial representations for classification. In this article, the crucial factors to discriminate spectral-spatial features are systematically summarized from the perspectives of feature extraction and feature optimization. For feature extraction, techniques to ensure the discrimination of spectral features, spatial features, and spectral-spatial features are illustrated based on the characteristics of hyperspectral data and the architecture of models. For feature optimization, techniques to adjust the feature distances between classes in the classification space are introduced in detail. Finally, the characteristics and limitations of these techniques and future challenges in facilitating the discrimination of features for HSI classification are also discussed further.

ASEAN REGULATION OF SENSITIVE SPACE TECHNOLOGIES IN COMPARATIVE PERSPECTIVE

Space technology has developed as a result of technology’s quick advancement. It is important to give attention to the development of space technology. This paper describes the regulation of sensitive space technology in ASEAN countries, which is made through a comparison table. Space-sensitive technology is advanced for conducting space activities, so it is prestigious for each country. Unlimited space makes it necessary to regulate the implementation of space activities. In general, the regulation of space activities is formed in international law. In particular, the regulation of space activities is formed in the national law of each country that has carried out space activities. The research methodology used is descriptive qualitative, with data sources from literature studies. The purpose of writing this research is to find out and compare how the regulation of sensitive technology of space activities in ASEAN countries can be a reference or reference for Indonesia in preparing national regulations on sensitive technology of space. The results showed that the comparison of sensitive technology arrangements in ASEAN countries is that Indonesia already has a Space Act that regulates the space sector. Malaysia has a Space Act and Space Regulations that regulate space activities. Singapore does not yet have a specific law governing sensitive space technology; however, the government adheres to this law.

Space Durable 3D Printed High‐Performance Polymers Based on Cyanate Ester/Extended‐Bismaleimide

AbstractTo accomplish the potential of the New‐Space emerging era and facilitate scientific and commercial space exploration, the development of versatile, customized, and affordable space technologies is essential. 3D printing is established as a disruptive technology, enabling the production of complex and lightweight structures with enhanced performance. However, the harsh conditions of the space environment, including atomic oxygen (AO), extreme temperatures, and ionizing radiation, pose significant challenges to the durability and longevity of additive manufacturing‐produced polymers. Until now, there are no additive‐manufacturing polymeric materials that are specifically developed and qualified to withstand space hazards. To address these challenges, novel materials for additive manufacturing, composed of cyanate ester and extended‐bismaleimide are engineered to withstand the extreme conditions in space. The developed materials demonstrate superior thermo‐mechanical properties (flexural stress of 72 MPa and Tg = 260 °C), enhanced durability to AO erosion, ionizing radiation (10 years in orbit), and thermal stability (Td5% = 360 °C). Moreover, it is found that printing orientation governs the AO erosion, thus guiding optimal printing designs for enhanced durability to AO. The materials show improved performance, endurance, and reliability, thus contributing to the development of space‐qualified components and enabling the advancement of additive manufacturing for future space missions.

Innovative design and development of attitude determination and control systems for CubeSats with reaction wheels

Attitude determination and control systems (ADCS) represent a critical facet of CubeSat missions, orchestrating the precise orientation and stabilization of these small satellites in the space environment. This paper presents a comprehensive design and development of an ADCS tailored for CubeSats, harnessing a reaction wheel system to deliver a cost-effective and dependable solution for small satellite applications. The research begins by elucidating the requisites and specifications for the ADCS and then delves into the design phase, complemented by intricate modelling and simulation employing MATLAB Simulink and the Webots Simulator. The results of this study underscore the exceptional performance of the proposed ADCS configuration, leveraging the reaction wheel model. This system demonstrates an unparalleled capacity to achieve precise and controlled attitude adjustments, well within the defined parameters. Furthermore, this research underscores the pivotal role played by efficient system design, meticulous simulation, and rigorous testing in the triumphant implementation of ADCS, greatly enhancing CubeSat missions and their contributions to the realm of space exploration and technology innovation. This comprehensive approach to the design and testing of an ADCS for CubeSats ensures that these diminutive satellites continue to make significant strides in space missions, paving the way for an exciting future of space research and technology development.

Criminalistics and Crime Scene Investigation in Microgravity Space

Addresses the challenges and considerations of criminalistics and crime scene investigation in extraterrestrial gravitational environments. Future space exploration may require the development of protocols for extraterrestrial crime scene investigations. Challenges in microgravity effects, confined space environments, forensic techniques, communication, coordination, and legal jurisdiction are highlighted in this brief. Microgravity effects create difficulties in dis-placing evidence, such as blood spatter patterns, which make interpretation of events difficult. Restricted areas such as spacecraft and stations require special techniques and equipment. Storing and securing evidence in microgravity makes traditional methods impractical. The lack of gravity affects fingerprint development and preservation, requiring the use of alternative methods. Compact and specialized equipment is required to analyze DNA in space. Communication de-lays hinder real-time collaboration between researchers on Earth and those in space. Guidance can be provided to personnel in space with remote technologies and autonomous systems. Determining legal jurisdiction for crimes committed in space or on spacecraft requires complex international cooperation and agreements. The development of space law, technology and international agreements is important to meet the challenges of extraterrestrial crime scene investigations. Future discussions and research will provide a basis for establishing protocols for extraterrestrial crime scene investigations to ensure effective and fair forensic practices. As space exploration progresses, advances need to be made in these areas. As space exploration advances, the development of space law, technology, and international agreements is crucial to meeting the unique challenges of extraterrestrial crime scene investigations. This summary provides a basis for future discussions and research regarding the establishment of protocols to ensure effective and fair forensic practices off Earth.

Numerical simulation of the effect of multiple factors on the ignition process of a solid rocket motor

AbstractWith the continuous development of manned space technology, higher requirements have been proposed for solid rocket motors. The ignition process of solid rocket motors affects the reliability, stability and safety of their operation. The ignition powder, cover opening pressure and grain length‐diameter ratio are the main factors affecting the ignition process. Therefore, the influence of different factors on the ignition process of solid rocket motors is studied with numerical simulations. Based on the finite volume method, the ignition process of a solid rocket motor is modelled and experimentally verified. Then, the pressure and temperature distribution characteristics during the ignition delay, flame propagation and gas filling times are analysed. Finally, the effects of different ignition powders, cover opening pressures and length‐diameter ratios on the ignition process are compared and analysed. The results show that the model has high prediction accuracy. When the ignition powder is 6 g, the maximum combustion temperature of solid rocket motor increases from 2590 K to 2620 K between 0.1 ms and 0.44 ms. Between 0.44 ms and 3.18 ms, intermittent flame propagation and pressure oscillations occur. In the gas filling time, the flow field gradually stabilizes. Increasing the ignition powder mass is beneficial to the ignition process, but the disadvantages of pressure oscillations should be considered. Increasing the cover opening pressure enhances the ignition process, while increasing the length‐diameter ratio increases the ignition pressure building time. The study results provide technical support for the structural design of solid rocket motors.

Lightweight zirconium modified carbon–carbon composites with excellent microwave absorption and mechanical properties

With the rapid development of space technology, multi-functional materials with advantages such as heat insulation, lightweight, and electromagnetic (EM) wave absorption have gained broad application prospects. Since porous carbon fiber reinforced carbon (C/C) composites often have lightweight and high heat insulation properties, improving their mechanical and electromagnetic wave absorbing properties will significantly expand their application. In this study, a new kind of zirconium-modified C/C (Zr-C/C) composites prepared by polymer infiltration and pyrolysis using zirconium-modified phenolic resin is presented. By adjusting the content of Zr, the compressive strengths of the composites are increased up to 48% compared with the composites without Zr, while the thermal insulation properties are little changed. The incorporation of zirconium can make the composites exhibit better microwave absorption performance to some extent, and Zr-C/C composites with 10% zirconium have the best microwave absorption performance among all the samples. The excellent electromagnetic wave absorption performance of Zr-C/C composites is attributed to the enhanced interfacial polarization effect and the improved electrical conductivities of the material due to its internal carbon microsphere structure. Multi-functional Zr-C/C composites that combine lightweight, high thermal insulation, high compressive strength, and high electromagnetic wave absorption have obvious applications in fields such as stealth aircraft. Therefore, this work provides a new way to prepare multi-functional materials.

Numerical and experimental research on the performance of an iodine-fed Hall thruster

The development of space technology brings about an increasing demand for electric thrusters. Iodine has been considered a feasible alternative to resource-critical xenon. Numerical and experimental methods are used to study the performance of the iodine-fed Hall thruster. The ionization and acceleration characteristics are investigated in the simulation with a particle-in-cell/Monte Carlo collision model. Different from previous simulations of noble gas, the dissociation equation of molecular iodine is added to the code for propulsive performance evaluation. A dissociation region in the discharge chamber is presented and described in detail. The propulsive performances of the iodine-fed Hall thruster are calculated by the plasma parameters. Meanwhile, the experimental measurements are finished for model verification and performance comparison at nominal conditions. The measured data is slightly lower than the simulated data. The error between them is about 1.65%. The reasons are analyzed and discussed. Then, the performance is predicted and measured using this simulated and experimental method within 20% mass flow rate and 10% anode voltage fluctuations relative to the nominal condition. Further optimizations of the simulation and experiment are in progress.

Connection-density-aware satellite-ground federated learning via asynchronous dynamic aggregation

With the development of space technology, the use of satellites for Earth observation is becoming more and more common. Among them, low-earth orbit (LEO) satellites have received a lot of attention because of their short return period and low cost. However, traditional satellite systems are unable to process data in orbit due to technical limitations and can only transmit massive amounts of data with useless information back to ground stations and then perform calculations, putting a tremendous strain on downstream bandwidth. Additionally, there are data walls between satellite affiliates, which makes it difficult to share and use data. To address the lack of data processing capabilities and data barriers in conventional satellite systems, as well as to effectively use satellite resources and enhance worldwide collaboration, we proposed a connection density-aware satellite-ground federated learning (FL) framework. According to this structure, satellites serve as workers in federated learning, analyzing data and transmitting the parameters to ground stations for aggregation. The ground station senses the satellite’s connection density during the aggregation process and implements a dynamic aggregation approach for the downstream parameters. Experiments based on real image datasets and on a simulated satellite network validate the effectiveness of the method in terms of execution efficiency and accuracy.

Analyzing SpaceX's International Collaborations: Conflicts and Coordination Mechanisms with Space Partners

Space exploration is a challenging and complex endeavor that requires collaboration between countries and organizations to advance. SpaceX, a leading private aerospace company, has engaged in various international collaborations with space agencies and partners to drive the development and application of space technology. However, international partnerships can also give rise to conflicts and issues that require suitable coordination mechanisms to resolve. SpaceX manages these challenges through cross-functional teams, effective project management, and shared knowledge. Strategies like diversity in partnerships enhance cooperation. SpaceX's experiences provide valuable insights for future space collaborations. SpaceX gets a lot achievements with its partners like NASA. And SpaceX do many efforts to deal with the troubles with them. SpaceX's approach to international collaborations in the field of space exploration revolves around cross-functional teams, effective project management, knowledge sharing, diversity in partnerships, a shared strategic vision, and a commitment to learning from experience.

Application of Private International Law in Space Travel at a Distance of Light Years Using Future Technologies

In particular, the article hints at the possibility of conflicts between states due to competition for resources in space, as well as the lack of full regulation of legal aspects in interstellar space. Particular attention is paid to the development of international treaties and mechanisms aimed at resolving these issues and ensuring peace and cooperation in outer space. Such documents can become the basis for creating a single legal space in outer space, where the rights and obligations of all entities will be clearly defined. The article concludes by emphasizing that the development of future space technologies requires a global approach to legal regulation to ensure security and stability in space, as well as the use of these new opportunities for the common benefit of all mankind. The article examines the topical issue of application of private international law to space travel over distances of light years using advanced technologies of the future. Travelling in space over such a vast distance is becoming increasingly realistic due to the development of astronomical research and technological progress. Legal aspects are an important aspect of such travel, as space activities raise numerous legal issues. Private international law defines the legal status of persons and objects in space representing different states. The application of this law requires resolving issues of jurisdiction, ownership, liability, and conflict resolution between different states and space actors. Future technologies, such as high-speed interstellar transportation and expanded habitat modules in space stations, introduce new challenges to the regulation of these issues. The article raises a lot of questions to which answers will still be found, and this process is a process that belongs to the future. At this stage, it is not known who else in the world would raise similar issues in the context of private international law, public international law, and international law in general.

Sustainable Space Travel: What Can We Do in Education from Economic and Environmental Perspectives?

Space travel began in 2001 and became popular in 2021 because of commercial operations. With the development of space technology and commercialization, like re-launchable rockets used to travel to space in recent years, hawse have gradually entered the space era. However, the space industry causes massive emissions, inducing some opposition to its development. It is essential to investigate the attitude of residents toward space travel and balance the pros and cons of sustainability. A quantitative analysis was adopted to test two models based on duality theory. The data were obtained from 284 samples from various regions of China and analyzed using partial least squares structural equation modeling (PLS-SEM). The results show that the two-factor model of economic development conflicted with environmental protection. However, study two indicates that educational interventions can facilitate sustainable space travel because they mediate the relationship between economic and environmental factors.

Long-term effects of ambient particulate matter on hypertension among royal Thai army officers: a retrospective cohort study

Recent research on the link between exposure to ambient particulate matter with an aerodynamic diameter up to 2.5 microns (PM2.5) and hypertension risk has primarily concentrated on spatial variation (or between-individual comparisons). Research into temporal variations (or within-individual comparisons over time) has largely been neglected. This study sought to examine the spatial–temporal effects of long-term exposure to PM2.5 on hypertension risk among military personnel in Thailand. A retrospective cohort study was conducted, encompassing 40,984 Royal Thai Army officers from 400 army units stationed across 51 provinces in Thailand. Medical check-up data from 2018 to 2021 were analyzed alongside ambient PM2.5 data from 2015 to 2017, sourced from the Geo-Informatics and Space Technology Development Agency. Two parameters, PM2.5-baseline and PM2.5-change, were introduced to assess the impact of spatial and temporal PM2.5 variations on hypertension incidence. Cox proportional hazard regression was used, with hazard ratios (HR) with 95% confidence intervals (95% CI) serving as the measure of association. The association between PM2.5-baseline and hypertension incidence yielded hazard ratios in Quartiles 2 to 4 compared to Quartile 1 of: Q2 HR: 1.19, 95% CI: 1.10–1.28; Q3 HR: 1.10, 95% CI: 1.02–1.20; Q4 HR: 1.13, 95% CI: 1.05–1.22. Additionally, the PM2.5-change showed a J-shaped association with hypertension incidence. Our findings underscore the role of both temporal and spatial factors in hypertension development and highlight the necessity for comprehensive investigations into the causal relationship between PM2.5 exposure and hypertension risk. They also provide valuable insights for devising effective strategies to mitigate the adverse health impacts of PM2.5 pollution.

Terminological correctness of the information environment through the eyes of physicists

The incorrectness of the concepts of "information society" and "information civilization" is considered, the justification of which is given by the author on the basis of the development of the information space and information technologies. It is shown that the use of these terms is one of the elements of the program of globalism, which threatens the transformation of the world space with the disappearance of nation-states and the domination of a transnational government. The latest trends in physical science are identified, where questions are raised about the importance of synthesizing quantum theory and general relativity with the existing problem of the possibility of combining local and non-local observations, the hypothesis of the existence of information fields. The integration of educational technologies is designed to show that the development of the information space is an important step in civilization, but humanity also faces more global challenges about the place and mission of Man in this world.

АНАЛІЗ ПІДХОДІВ ДО ВИДАЛЕННЯ ХМАРНОСТІ НА КОСМІЧНИХ ЗНІМКАХ ДИСТАНЦІЙНОГО ЗОНДУВАННЯ ЗЕМЛІ

The modern development of space technologies and remote sensing creates unique opportunities for solving problems in many areas, including the military. Remote sensing imagery often plays a key role in decision-making at all levels of military command, so one of the most important tasks in this context is cloud detection and extraction. This is an important stage of remote sensing data processing aimed at reconstructing information hidden by clouds. The article is devoted to the analysis of different approaches to cloud removal and improvement of the data quality. The approaches based on the use of various image processing algorithms (traditional approaches) have certain limitations associated with the frequent loss of useful information. Special attention is paid to deep learning methods, which have gained popularity in solving cloud removal problems. Deep Neural Networks show great potential for recovering information on satellite images that is hidden by clouds. This paper discusses various Deep Neural Networks architectures, such as convolutional neural networks, conditional generative adversarial networks, and their modifications. Their advantages and disadvantages are also considered. The use of such methods is more accurate and efficient compared to traditional image processing methods, as neural networks can adapt to various conditions and types of images. The analyzed disadvantages of fusing purely optical data led to the conclusion that the best approach to solving the problem of removing clouds from satellite images would be to combine optical and radar data. Despite the complexity of such an approach, it can show the greatest efficiency in solving the problem considered in this article. The challenges and prospects for further improvement of cloud removal methods on satellite images are considered. In particular, the use of artificial intelligence algorithms for automatic cloud detection and removal, as well as the need to create standardized methods for comparing and evaluating the effectiveness of different approaches. Keywords: satellite imagery; remote sensing; cloud cover; neural networks.

Promising methods for improving the radio-frequency ion thruster performance

Improving the reliability and efficiency of available electric propulsion schemes is one of the priority areas of space technology development. In particular, this should be done for ensuring the guaranteed removal of spacecraft to a disposal orbit at the end of their active life, which, in turn, will slow down the growth in the number of space debris objects in the most exploited regions of near-Earth space. The paper considers ways to improve the power and mass efficiency of one of the modern electric propulsion types - a radio-frequency ion thruster with an inductive radio-frequency discharge. Using an engineering physico-mathematical model, computational studies were performed to optimize the shape of the radio-frequency ion thruster main components, namely the discharge chamber and the grids of ion-extraction system. The thrust of the thruster was used as the optimization criterion; it was determined from the calculated ion density distributions in the radio-frequency discharge plasma. Such an approach to refine the performance improvement methods has not previously been applied to radio-frequency ion thruster. The ion density distributions, as well as the thruster integral characteristics determined from them, such as the thrust, total ion current from the thruster, propellant utilization factor, ionization cost and a number of others, were calculated for two actual standard sizes of radio-frequency ion thruster with the beam diameters of 80 mm and 160 mm, which can be used to solve the problems listed above. Besides, for the defined optimal configurations of thruster with two standard sizes the calculations were made to assess the possibility for increasing the thruster integral characteristics by applying an additional magnetostatic field in the radio-frequency discharge region. The study revealed the possibility of noticeable performance improvement compared to the basic radio-frequency ion thruster design with hemispherical discharge chamber and flat grids of the ion-extraction system.