Space Surveillance Network [ edit ]

The United States Space Surveillance Network , a division of the United States Strategic Command since the beginning of the space age with the launch of Sputnik 1 by the Soviet Union in 1956.(SSN) is following objects orbiting the earth. Since then, SSN has tracked more than 26,000 objects. SSN is currently tracking more than 6,000 artificial satellites. The rest have re-entered the Earth's atmosphere and become isolated, or have remained intact during re-entry and crashed into the Earth. SSN tracks objects with a diameter of 10 centimeters or more; This includes the cost of a rocket weighing just 10 pounds, with a few tons of artificial satellites currently orbiting the Earth. About seven percent of the active satellites (i.e. ~ 560 satellites), all the rest are space debris . ^[15] The U.S. Strategic Command is primarily interested in active satellites, but also tracks space debris that may be mistaken for incoming missiles.

There are three primary categories of satellite (civilian) services: ^[16]

Fixed satellite service [ edit ]

Static satellite services handle hundreds of billions of voice, data, and video transmissions across specific points on Earth's surface across countries and continents.

Mobile satellite services [ edit ]

In addition to serving as a navigation system, mobile satellite systems help connect remote areas, vehicles, ships, people and aircraft to other parts of the world or to other mobile or stationary communications units.

Scientific Research Satellite (commercial and noncommercial) [ edit ]

Scientific research satellites provide information on weather data, land survey data (e.g. remote sensing), amateur (HAM) radio, and other scientific research applications such as geology, marine science, and atmospheric research.

• Astronomical satellites are satellites used to observe distant planets, galaxies and other outer space.

Hubble Space Telescope

• A biosatellite is a satellite designed to carry living creatures for scientific experiments.
• Communication satellite A satellite placed in space for the purpose of telecommunication . Modern communications satellites typically Geosynchronous orbits , Molniya orbits or low Earth orbit using.
• Earth observation satellites are satellites designed for civilian use, such as environmental monitoring , meteorology , mapping ,etc. (See Earth observation system )
• Direction satellites are satellites used by mobile receivers to determine one's exact position using radio time signals.
• Killer satellites are satellites built to destroy enemy warheads, satellites and other space resources.
• Sailor spacecraft are huge satellites that are able to place people in an orbit and bring them back to Earth. (US Apollo lunar module program was an exception, because it did not have the power to bring people back to earth.) Re-use of the space flight of the spacecraft with greater propalasana or landing facility. In orbital stations and they can be used as transport. These can be used at orbital stations and for transportation from there.
• Miniaturized satellites are unusually low-mass and small-sized satellites. ^[18] New classifications are used to classify these satellites: minisatellite (500–1000 kg), microsatellite (below 100 kg), nanosatellite (below 10 kg). ^{[ Citation needed ]}
• Inspection satellites areearth observation satellites or communications satellites designed for military or intelligence purposes. Little is known about the full power of these satellites, as the governments that operate them usually keep secret information about their visiting satellites.
• Recovery satellites carry out inspections, biological, space production and transport of other objects from orbit to Earth.
• Space-based solar power satellites are proposed satellites that collect energy from sunlight and send it to Earth or elsewhere.
• A space station is an artificial structure in orbitdesigned for human survival in space . What sets one space station apart from other crew spacecraft is its lack of large propulsion facilities. Space stations are designed for medium-term stays in orbit for weeks, months, or even years.

 In the context of space travel , a satellite is an object that has been intentionally placed in orbit. These objects are called artificial satellites to distinguish them from natural satellites such as the Earth's moon .

On October 4, 1956, the Soviet Union launched the world's first artificial satellite, Sputnik 1 . Since then, about 6,900 satellites have been launched from more than 40 countries. According to a 2016 estimate, about 5,000 are still in orbit. Of these, about 1,900 are in operation, but the rest have gone through their lifetimes and become space debris . About 63% of working satellites are in low Earth orbit , 7% in Earth's middle orbit (20,000 km), 29% in Earth orbit (36,000 km) and the remaining 2% in various elliptical orbits.There are. Among the countries with the most satellites, the United States has the most with 759 satellites, followed by China with 220 satellites and Russia with 147 satellites. It is followed by India (116), Japan (72) and the United Kingdom (52). ^[1] International Space Station with a few large space station partially was launched and in orbit were gathered. More than a dozen space probes have been placed in orbit around other objects , including the Moon , Mercury , Venus , Mars , Jupiter , Saturn , a few asteroids , ^[2] a comet.And has become an artificial satellite of the sun .

Artificial satellites are used for a variety of purposes. In a number of applications, artificial satellites can be used to map and map the surface of the planet and to take pictures of the planet on which the satellite was launched. Common types include military and civilian Earth observation satellites , communications satellites , directional satellites , weather satellites and space telescopes . Orbital space stations and spacecraft are also artificial satellites.

Satellites can work on their own or as part of a larger system for a satellite organization or satellite.

The orbits of artificial satellites vary greatly according to the purpose of the satellite and these orbits are classified differently. Well-known classes (overlays) include the lower Earth orbit, the polar orbit, and the terrestrial orbit .

A launch vehicle is a rocket that puts a satellite into orbit. Typically, it moves from a launch pad to the ground. Some are launched from a submarine or a mobile marine platform towards the sea, or on top of an aircraft (launch from the aircraft into orbit).

Artificial satellites are usually semi-standalone computer-controlled systems. Satellite subsystems perform many functions such as power generation, heat control, telemetry, pose control, scientific instruments, communications , and so on.

The first published mathematical study of the possibility of artificial satellites was Newton 's Cannonball , which was published in Isaac Newton's Philosophia Naturalis Principia Mathematica (18) as a thought-provoking study to explain the motion of natural satellites . The first fictional depiction of the launch of an artificial satellite into orbit is a short story by Edward Everett Hall , "The Brick Moon" (189). ^[3] [4] This idea is repeated in Jules Verne's Begum Ratnabhandar ( 189 ).

In 1903, Konstantin Tsiolkovsky (1858-1935) published Exploring Space Using Jet Propulsion Devices , the first textbook on the use of rocketry for spacecraft launches. He calculated the orbital velocity required for the minimum orbit and also calculated the ability of a multistage rocket powered by a liquid propellant to achieve this velocity.

In 1926 , Herman Potonik (1892–1929) published his only book, The Problem of Space Travel - The Rocket Motor . He described the use of orbiting spacecraft for ground observations and how special space conditions could be effective in scientific experiments.

In a 1945 article in Wireless World, English science fiction writer Arthur C. Clarke detailed the possible use of communication satellites for mass communication . ^[5] He suggested that three geostationary satellites would serve the entire planet.

In May 1948, the U.S. Air Force Project RAND released the preliminary design of an experimental world-orbiting spacecraft, stating that "an artificial satellite with suitable equipment could be expected to be one of the most powerful scientific instruments of the twentieth century." ^{[6] The} United States has been considering launching satellites into orbit since 1954 under the auspices of the United States Navy's Aeronautics Bureau. Project Rand finally released the report, but considered the artificial satellite to be a tool of science, politics, and propaganda rather than a possible military weapon. ^[৭]

In 1946, the American theoretical astronomer Lyman Spitzer proposed an orbiting space telescope . ^[৮]

In February 1954, Project Rand published "Scientific Use of Artificial Satellites" by R. R. Carhart. ^[9] It was expanded by the potential scientific use of artificial satellites, and in June 1955 H.K. Coleman and WW. Kellogg's "Scientific Use of Artificial Satellites" was published. ^[10]

In the context of planning activities for the International Year of the Earth (1958–56), the White House announced on July 29, 1955 that the United States planned to launch a satellite by the spring of 1956. It came to be known as the Vanguard Project. On July 31, the Soviets announced that they would launch a satellite by the end of 1957.

The first artificial satellite was Sputnik 1 , launched in 1954 by the Soviet Union under the Sputnik program with Sergei Korolev as chief designer. Sputnik 1 helped detect the density of the upper atmospheric layers by measuring its orbital change and provided information on the distribution of radio-signals in the ionosphere . The unexpected announcement of the success of Sputnik 1 alarmed the Sputnik crisis in the United States and ignited the so-called space competition in the Cold War .

Sputnik 2 was launched on November 3, 1955, and carried the first living astronaut , a dog named Leica , into orbit. ^[11]

In early 1955 , under pressure from the American Rocket Society , the National Science Foundation, and the International Geopolitical Year, the Army and Navy were working on Project Orbiter with two competitive programs. The military used the Jupiter C rocket , while the civilian / naval program used vanguard rockets to launch satellites . On January 31, 1956, Explorer 1 became the first artificial satellite in the United States. ^[12]

In June 1981, three-and-a-half years after the launch of Sputnik 1, the United States Space Surveillance Network compiled a list of 115 artificial satellites orbiting the Earth. ^[13]

The early satellites were built in unique designs. With the advancement in technology, multiple satellites began to be built on a single model platform called satellite bus . The standard satellite bus nakasasampanna jiosinakronasa (jiio) communications satellite HS -333 197 was launched in.

Currently the largest artificial satellite is the International Space Station . ^[14]