نشریه علوم و فناوری فضایی
سال هفدهم شماره 2 (پیاپی 61، تابستان 1403)

Satellite constellations include a set of similar satellites that are distributed in a specific orbital pattern to accomplish a common mission. The satellite constellations are commonly used to accomplish missions such as global telecommunications, global positioning, and remote sensing. In this article, by using scientometric approach, the structure and scientific maps of field of "satellite constellations" in the world, as well as two leading countries, including United States and China, have been analyzed based on research documents published in this field. In addition, a comparison has been made between United States, China and the world. The research community includes all scientific documents in the field of "satellite constellations" that have been indexed in the "Scopus" database between 1969 and 2023 AD. Moreover, in this article, knowledge maps (thematic subfields) and international cooperation maps of countries have been drawn using Bibexcel and VOSViewer software. The number of documents published in this time period in the world, United States and China includes 14346, 3738 and 3369 documents, respectively. The findings of the research show that United States, China, Germany, Italy and England are leading in this field. Also, the trend of Scientific productions in this field in the world is on the rise, which shows the importance and attractiveness of this scientific field. Conference papers have the largest amount of documents published in the world and the United States; While the most documents published in China are related to articles published in journals. The top scientific production institutions in this field in the world include the National Aeronautics and Space Administration (NASA), the Chinese Academy of Sciences, the German Aerospace Center, Wuhan University, and the European Space Research and Technology Center, respectively.

One of the current problems in the development of simulation software of flying objects is the process of software development and development from the concept design phase of a project to the final stages of the hardware in the loop. In this paper, the necessary software engineering standards and procedures for the production of rigid multi-stage launch vehicle simulation software with a new approach are introduced in order to overcome this problem. The proposed RUP structure for the production of software with six degrees of freedom simulation software's ability to be used quickly and with minimal modifications in loop software and loop hardware labs.

The aim of this research is to optimize the trajectory of a low-trust spacecraft carrying biological cargo. Reducing the radiation stresses of the Van Allen belt is the optimal criterion of the optimal control problem of the orbital transfer from the low orbits to the high orbits. Since the minimum radiation stress criterion introduced in this article is not among the conventional optimality criteria, solving the above optimal control problem will be complicated and the honey bee optimization method has been used. The optimization of the path in this article is done by rewriting the motion equations based on the control variable and solving the new motion equations with the help of bee optimization. The main advantage of the method used in this problem is the use of optimal control theory and population-based optimization methods with a global approach. In the presented new method, the optimal control problem is simplified by redefining the differential equation system, and the results show the accuracy and ease of solution. Results of the optimal criterion of the minimum time and the minimum radiation stresses presented in this article, the criterion of the minimum radiation causes an increase of 8.89% in the transfer time.

The prioritization and verification of space emerging technologies is a multi-step, iterative process that needs to collective intelligence (the participation of all stakeholders), as well as the use of analytical methods to identify requirements. This process begins with identifying specialists who have enough knowledge and experience regarding to each technology, and followed by extracting and evaluating the necessary data, prioritizing technology options, identifying challenging technologies and the essential acquisition strategy, and finally prioritizing them. In this article, we implemented a method to identify and prioritize some space technologies which could be used in the electrical power subsystem (EPS) of a satellite. Based on the results, it would be possible to choose the best method to access the required technology; national development or benefiting of available technology in the market. To evaluate the suggested method, the power subsystem components are divided into three categories: electrical power generation sources, energy storage sources, and power electronic circuits. Applying the proposed method shows that the selected technologies are those is recently used in space. This method can also be applied to other subsystems.

This paper deals with semi-analytical modeling and stability analysis of a coupled slosh-tank dynamics as a multibody system using the Homotopy Perturbation Method (HPM). The sloshing motion of the liquid inside the tank is considered as the equivalent pendulum model. The nonlinear equations of the motion under lateral and longitudinal excitations (compressive oscillations) are derived using the Lagrangian approach. In this model, the effects of essential parameters such as viscous damping, amplitude, and frequency of the excitation are studied for two typical points inside and outside the stability regions. It has been shown that viscous damping, compared to other principle parameters, brings the points located in the unstable region closer to the stable region. The simulations in terms of stability diagrams, phase portraits, and time histories of sloshing amplitude are achieved using HPM and compared to the numerical Runge-Kutta method to follow the stability phenomena and highlight the analytical approach's validity.

Achieving to new technologies with high reliability, along with reducing the cost and time of the design cycle, is one of the most important challenges in complex systems. In this paper, reliability based design of a space system is discussed in the conceptual design phase. Normally, there are eight steps in the design for reliability. The first step, planning, and the next seven steps that applied for the liquid propellant engine with electro-pump technology included: determination of failure modes; reliability modeling; reliability allocation; propagation of uncertainty; Implementation of the chosen method in reliability analysis; reliability prediction and reliability evaluation. Therefore, in this research has been performed to achieved method and implementation steps of reliability design in the conceptual design phase of a space system.

In recent years, the interest in using small satellite constellations has increased due to the reduction of cost and time as well as the greater capabilities of small satellites. This is despite the fact that today, due to high launch costs, new launch strategies have replaced the traditional methods of launching constellations to mission orbits. Depending on the mission of the constellation, various methods have been proposed for launching and deploying satellites in the mission orbit, which are classified in one of two categories, direct or indirect. In this paper, an indirect method for deploying the satellites of a constellation to several orbital planes has been investigated. This method is based on changing the orbital planes with the positive use of the earth's oblateness perturbation in addition to using the satellite propulsion subsystem. This method has been simulated and analyzed for two real satellite constellations with remote sensing and global internet missions. Also, based on this method, the launch and deployment strategy for a regional satellite navigation system covering Iran with 130 satellites has been designed and implemented. The obtained results have been analyzed in terms of the time required for the launch and the required ΔV.