In the early 20th century, the foresight in the universe realized that by putting satellites in track, people on the earth could directly have specific profits. for example, (Arthur C Clark in 1945 explained how three satellites in the orbit of about 35800 km (22250 miles) can relay communications around the world. In this trajectory, the satellite is the Earth. It has an equal orbital cycle, so it seems to be still in the sky from the ground (see Spaceflight: EARTHORBIT) in 1946. The U.S. Army Air Force report has identified the bomb shock sites dropped by the US aircraft.
Space development, space development, which is a practical application of spacecraft abilities and data collected from space, has evolved in parallel with space exploration. Space applications have two common categories. One provides profits that are not easy to sell to public goods, or individual buyers. Therefore, it is usually provided by the government using public funds. Examples of public space applications include weather. Navigation, position, and timing. Use of military and national security. Applications in other categories provide products or services that can be sold to buyers by profit. These applications are the basis of commercial development of space by the private sector. Examples of existing commercial space application include various types of communication and data transmission of satellites, remote sensing on the surface of the earth, and commercial space transport. Other applications such as space sightseeing, space -based power generation, high -value material manufacturing in microscopic environment, and commercial development of extraterrestrial resources may appear in the future.
Many space applications have both the private and military use, so similar systems are being developed by both sector. Effectively managing and using these double -purpose systems is a continuous policy issue.
Meteorological scholars initially thought about it The satellite is mainly used to observe the pattern of the clouds, and therefore provide an imminent storm warning. They did not expect space observation to be the center of improving the weather forecast overall. Nevertheless, because the cosmic -based mechanic technology was more sophisticated, satellites were asked to provide three -dimensional profiles of additional variables in the atmosphere, such as temperature, moisture content, and wind speed. These data are important for modern weather forecasts.
The meteorological satellite is placed in one of the two types of orbit. The global orbital satellite provides continuous cloud patterns in a wide area of the surface of the earth. From these changes in these patterns, weather scholars can guess the wind speed and find the developed storm. The lower orbit satellites are lined up in the north -south direction, The polar orbit can get more detailed data on changes in atmosphere conditions. It also provides repetitive global coverage as the earth rotates under the orbit. In the United States, military and private institutions are developing independent polar track meteorological satellite systems. China, Europe and Russia also develop their own polaral orbit satellites. The United States, Europe, Russia, China, India, and Japan are on tracks with still weather satellites.
R & D activities required for the production of meteorological satellites are carried out by various space organizations, but the control of satellite operation has been handed over to an organization that has a general responsibilities of weather forecasts. In the United States The National Ocean atmosphere (NOAA) operates the global and polar orbital satellites for short and long -term predictions. The Pentagon (DOD) has also developed a similar satellite for military use. In Europe, inter -government -organizations are called EUMETSAT was created in 1986 to operate European weather satellites and provide observation to national meteorological services. Institutions around the world cooperate with changing data from satellites. Meteorological satellite is an excellent example of both the ability of the space system to provide a very valuable profit to mankind and the need for international cooperation to maximize their interests.
Positioning, navigation, and timing
In 1957, scientists tracking the first satellite, SPUTNIK 1 discovered that by analyzing the doppler shift (see the doppler effect) by the frequency of the sentence sent on the fixing position on the earth, SPUTNIK 1 can be very accurate. If this process could be reversed, it would be possible to use information from those satellites to identify places on the earth if some satellite orbitals were accurately known. understood.
This realization led the United States and the Soviet Union to develop satellite -based voyage systems in the 1960s and early 70s, combined with the need to establish a submarine -equipped submarine. However, these systems did not provide very accurate information and were difficult to use. Later, both countries have developed US Navstar, a second -generation product. Global positioning system (GPS) and Soviet The global navigation satellite system (Glonass) did a lot to solve the problem of the predecessor. The original purpose of the system is the support of military activities, and they continue to work under military management, while using various private use.
GPS requires a minimum of 24 satellites, and four satellites are distributed in six orbit. The complete complement of satellite was completed in 1994, including continuous replenishment and updates, and some spare satellite maintenance. Each satellite has four accurate atomic clocks in one nano second. The orbit of the satellite is very accurate by the grounding controller, and the time signals from each satellite are very accurate, so users with a GPS receiver can determine the distance from a minimum of four satellites. With three dimensions with about 3 meters (10 feet) horizontally and 5 meters (16 feet) accuracy vertically.
Glonass, operated in 1995, functions in the same general principle as GPS. The completely deployed system consists of 24 satellites distributed in three orbit. However, due to Russian economic difficulties, Glonas has not been maintained for several years, and the exchange satellites have been slow. However, due to the improvement of the economic situation, the Russian government gave priority to fully operating and maintaining a glonas system.
Despite the military origin of GPS and Glonass, civilian users have grown. They range from wild field camper, farmers, golfers, recreational sailors, surveyors, automotive rental companies, buses and truck fleets, and airlines around the world. The timing information from the GPS satellite is also used on the Internet and other computer networks to manage the flow of information. The user has found a method of increasing the accuracy of the position to a few centimeters by combining the GPS signal with the ground -based extension or glonas signal.
The United States regards the GPS as a global utility provided to all users, stating that the system is intended to maintain and upgrade the system in an indefinite future. However, there are concerns that important global private activities, such as air traffic control, should not be dependent on systems controlled by the army of a country. In response, Europe began in the late 1990s to develop a unique navigation satellite system called Galileo to operate under private management. Galileo was in operation in 2016. In the early 21st century, China began developing a unique global navigation system called Baydow (“Compass”). Initially, Baydow, which was composed of three satellites in China’s Earth Competition, began operations in 2000. A complete version of Baydu was completed in 2020. Japan and India have developed a system for regional use. The constellations (NAVIC) operated in 2018.
Use of the universe of military and national security
Countries and organizations with the military have quickly recognized the very usefulness of the cosmic -based systems in military operations. The United States, Russia, the United Kingdom, France, China, the North Atlantic Treaty (NATO), and other European countries are developing more and more sophisticated space systems. Communication, weather, positioning, positioning and positioning and navigation -it is dedicated to military purposes. In addition, the United States and Russia have developed satellites to provide early warnings for launching a hostile missile. Many of these satellites are designed to meet their own military requirements, such as the ability to operate in a wartime environment where the opponent tries to hinder their functions.
Until now, the military space system has mainly helped to enhance the effectiveness of the army on the ground, air, and seabed. Commanders can communicate with the forefront of the army, depending on the satellite, and in extreme situations, the national authorities can use them to issue orders to fire nuclear weapons. Meteorological satellites are useful for planning air strikes, using satellite placement to lead weapons to high -precision targets.
Despite the large military use of the universe, no country has developed a space system that can attack orbit satellites or supply weapons to earth targets. Nevertheless, it is not clear whether more countries will acquire military space abilities and continue to be treated as a weapon without weapons as regional and regional disputes continue around the world.
In addition to recognizing the value of the space system in the war, the ability to collect information on surface -based activities such as weapons development, development, and military movements will support the plan. I recognized that early. Their national security activities. As a result, the two countries have developed various space systems to collect intelligence. These include a reconnaissance satellite that brings high -resolution images of the earth’s surface to real time to use intimidating activities, planning military operations, and monitoring weapon management agreements. Other satellites collect electronic signals such as telephone, radio, Internet messages, and other emissions. This can be used to determine the type of activity performed in a specific location. Most national security space activities are being carried out in a very secret way. Other countries such as France, Germany, Italy, China, India, Japan, and Israel have developed similar abilities due to the clarification of such satellite systems for national security. We are planning our own system.
