This study introduces a new computer code termed AZMIN developed by Space Research Laboratory (SRL). This efficient tool which benefits from the Statistical Design Model (SDM) has been developed for the system design of GEO COMMUNICATION SATELLITES. The main advantage of the AZMIN is to determine technical specification parameters of a satellite at both system and subsystem levels, with a high accuracy and time performance. System-level parameters encompass mass, power, dimension and cost; while, subsystem parameters contain mass, power, and solutions for components configurations of each subsystem. Actual computations of this tool are carried out by means of SDM, leading to a dramatic decrease in the conceptual design time and consequently, its cost. The database utilized is composed of records of 462 GEO COMMUNICATION SATELLITES launched from the year 2000 to 2017. The accuracy of the AZMIN code is amply verified through an example and also a statistical method, demonstrating the mean error of approximately 15% in the obtained results.

The world is embroiled in a pandemic of a new coronavirus at the end of 2019 and early in 2020, with such a large scale that it has severely involved the political, economic, and social systems in most countries around the world. The scale of the crisis is so widespread that many experts believe that the post-corona world will be substantially different from the pre-corona world. In the face of this massive epidemic, how people perceive risk and how to risk is communicated, plays a central role in deciding and choosing people's behavior. Fighting with this emerging phenomenon requires mobilizing all the possibilities of society and helping all people in the field of empathy and altruism. In this article, we briefly review aspects of the important concept of risk perception and COMMUNICATION in this pervasive crisis.

Due to high design and launch cost of SATELLITES, their failure probability should be minimized. Single Event Effects (SEUs) are one of the most common error sources in satellite microelectronic. To cope with these unwanted errors, various techniques are used. The reliability analysis of these methods is one of the major acceptance criteria to validate these techniques. In order to evaluate the reliability of satellite subsystems, it is required to determine the SEU rate as a primary factor. A practical method to determine this rate is based on Weibull approach in which the SEU cross section is used as an initialized parameter. In this paper, the SEU rate is calculated based on weibull method for Low Earth Orbit (LEO) SATELLITES, as case study Iranian demonstrated Rasad and Omid SATELLITES. Furthermore, based on the proton density, an accurate time-varying SEU rate model is proposed which determines the rejuvenation time for SEU susceptible subsystems.

The thermal control subsystem (TCS) of SATELLITES is responsible for providing and maintaining the allowable temperature of that satellite equipment. Naturally, if this subsystem is not properly designed, other subsystems, including the payload, will not be able to do their duties. In general, there are two active and inactive methods for designing TCS. Studies show that the elements can be suitable for controlling the temperature of a small-scale satellite (SSS) which has low weight, volume, and power consumption. Therefore, passive temperature control this equipment is widely used in SSS. The most common of these equipment are coatings, insulators, and paints. But some active elements are commonly used to make the thermal design of small SATELLITES safer. Heaters are more common among thermally active elements, because they .have less volume and weight than other active equipment, and consume less power than other elements

Conventional magnetic attitude control methodologies require several orbital periods to accomplish the required attitude maneuvers due to the existence of an uncontrollable axis, namely the local Earth's magnetic field vector. Since in some attitude maneuver missions the elapsed time is of critical importance, those time-consuming controllers are not satisfactory, and we need a much faster controller to achieve the maneuver in a fraction of an orbit. In this research the attitude slew maneuver using magnetic torques is formulated as a time optimal problem and solved through the calculus of variations. The resulting controller is shown to be very fast in forcing the attitude to converge to the desired condition.

Background and Objectives: Earth has a complex ecosystem that is affected by natural processes and human activities, and understanding these processes is a real necessity. Environmental changes, from climate change to the reduction of natural resources, affect human life, economies, and the well-being of future generations. Therefore, the need for comprehensive Earth observation has never been more critical. To address this need, the Copernicus program was created by the European Space Agency in the early 2000s. The goal of this program was to create an operational system for earth monitoring with open access to high quality satellite data. The Sentinel SATELLITES, as the core of the Copernicus program, is one of the symbols of humanity's progress in earth observation and environmental monitoring. This research examines the Sentinel SATELLITES and shows the importance, basic principles and unique features of each of them. Sentinel SATELLITES are unique operational platforms compared to the SATELLITES of the previous generation.Methods: In this paper, the main framework of the Copernicus program, such as open access to satellite data, global coverage, operational stability, diverse sensors, and the framework of global cooperation, which is of great help to researchers, policymakers, and other users of satellite data, has been evaluated. The Sentinel SATELLITES includes several SATELLITES that acquire images from the earth in different spectral ranges, with global coverage and different viewing times. These SATELLITES have operational stability and new generations of SATELLITES are developed and launched to replace older SATELLITES. Each satellite is equipped with special sensors according to its mission goals and makes it possible to monitor the land, oceans and atmosphere with the best possible tools from space.Findings: The Sentinel-1 satellite, which is equipped with a radar sensor, can image in the C frequency band and different spatial powers from 5 to 40 meters. Also, this satellite is able to take images in any weather conditions and at any hour of the day and night, which is valuable for many applications. The accuracy of Sentinel-1 data is very high in monitoring changes in the shape of the earth's surface, crisis management, polar ice observations and ocean monitoring. This vital role in detecting and monitoring land subsidence in urban areas makes it effective in urban planning and helping to prevent crises. On the other hand, the Sentinel-2 satellite with a multispectral sensor provides a powerful tool for Earth observation. By recording data in a wide spectral range in 13 spectral bands from visible to short-wave infrared, this satellite has been able to deepen our understanding of the features of the Earth's surface. The re-viewing time of this satellite has made it possible to monitor crops and evaluate the health of vegetation. Also, the spatial resolution of Sentinel-2 satellite images is an effective factor in urban planning, tree health monitoring, and natural disaster monitoring, such as fire and flood. In addition, the high bandwidth of this satellite helps to efficiently cover large areas and increases its efficiency in environmental monitoring.Conclusion: The Copernicus program is known for several key principles that have underpinned their success. These principles include open access data, global coverage, operational interoperability, diverse sensors, and a global cooperation framework. The principle of open access has given the assurance to the general users, including researchers, policymakers and commercial companies, that a continuous flow of satellite images will support their activities. The Copernicus program with a system of SATELLITES ensures global coverage with optimal revisit time. The operational continuity of the program has resulted in new generations of SATELLITES being developed and launched to replace older generations, to ensure a continuous flow of data. Each Sentinel satellite is equipped with specific sensors designed for its mission objectives, enabling it to monitor the Earth, oceans, atmosphere, and more. According to the characteristics of the Copernicus program, Sentinel SATELLITES have started a new era of Earth observation and have provided a powerful and versatile tool for monitoring and understanding the Earth's ecosystem.