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Geostationary
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitude above Earth's equator, in radius from Earth's center, and following the direction of Earth's rotation. An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite antennas do not have to rotate to track them but can be pointed permanently at the position in the sky where the sat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosynchronous Orbit
A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital period means that, for an observer on Earth's surface, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day. Over the course of a day, the object's position in the sky may remain still or trace out a path, typically in a figure-8 form, whose precise characteristics depend on the orbit's inclination and eccentricity. A circular geosynchronous orbit has a constant altitude of . A special case of geosynchronous orbit is the geostationary orbit (often abbreviated ''GEO''), which is a circular geosynchronous orbit in Earth's equatorial plane with both inclination and eccentricity equal to 0. A satellite in a geostationary orbit remains in the same position in the sky to observers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Radio receiver, receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The radio waves used for telecommunications links travel by Line-of-sight propagation, line of sight and so are obstructe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather Satellite
A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites are mainly of two types: polar orbiting (covering the entire Earth asynchronously) or geostationary (hovering over the same spot on the equator). While primarily used to detect the development and movement of storm systems and other cloud patterns, meteorological satellites can also detect other phenomena such as city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, and energy flows. Other types of environmental information are collected using weather satellites. Weather satellite images helped in monitoring the volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna. Smoke from fires in the western United States such as Colorado and Utah have also been monitored. El Niño and its effects on wea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graveyard Orbit
A graveyard orbit, also called a junk orbit or disposal orbit, is an Orbit (physics), orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellites are moved into such orbits at the end of their Spacecraft retirement, operational life to reduce the probability of colliding with operational spacecraft and generating space debris. Overview A graveyard orbit is used when the change in velocity required to perform a de-orbit Orbital maneuver, maneuver is too large. De-orbiting a geostationary satellite requires a delta-v of about , whereas re-orbiting it to a graveyard orbit only requires about . For satellites in geostationary orbit and geosynchronous orbits, the graveyard orbit is a few hundred kilometers beyond the operational orbit. The transfer to a graveyard orbit beyond geostationary orbit requires the same amount of fuel as a satellite needs for about three months of Orbital s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Rosen (electrical Engineer)
Dr. Harold Allen Rosen (20 March 1926 – 30 January 2017) was an American electrical engineer, known as "the father of the geostationary satellite", and "father of the communications satellite". He formed and led the team that designed and built the first geosynchronous communications satellite, Syncom, for Hughes Aircraft Company. Early life Harold Allen Rosen was born on March 20, 1926, in New Orleans, Louisiana. He served as a radio communication and radar technician in the U.S. Navy during World War II, from 1944 to 1946. His experiences in the Navy provided him with hands-on experience with radio communications and the then-new field of radars. He graduated from Tulane University in New Orleans in 1947 with a Bachelor of Engineering degree in electrical engineering. He received an M.S. and a PhD in electrical engineering in 1948 and 1951 respectively from the California Institute of Technology in Pasadena.Hagerty, James, Engineer launched commercial satrellite era, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit
In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syncom 2 Side
Syncom (for "synchronous communication satellite") started as a 1961 NASA program for active geosynchronous communication satellites, all of which were developed and manufactured by the Space and Communications division of Hughes Aircraft Company (now the Boeing Satellite Development Center). Syncom 2, launched in 1963, was the world's first geosynchronous communications satellite. Syncom 3, launched in 1964, was the world's first geostationary satellite. In the 1980s, the series was continued as Syncom IV with some much larger satellites, also manufactured by Hughes. They were leased to the United States military under the Leasat program. Syncom 1, 2 and 3 Common features The three early Syncom satellites were experimental spacecraft built by Hughes Aircraft Company's facility in Culver City, California, by a team led by Harold Rosen, Don Williams, and Thomas Hudspeth. All three satellites were cylindrical in shape, with a diameter of about and a height of about . Pre- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation Satellites
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). , four global systems are operational: the United States's Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System (BDS), and the European Union's Galileo. Two regional systems are operational: India's NavIC and Japan's QZSS. ''Satellite-based augmentation systems'' (SBAS), designed to enhance the accuracy of GNSS, include Japan's Quasi-Zenith Satellite System (QZSS), India's GAGAN and the European EGNOS, all of them based on GPS. Previous iterations of the BeiDou navigation system and the present Indian Regional Navigation Satellite System (IRNSS), operationally known as NavIC, are examples of stand-alone operating regional navigation satellite systems (RNSS). Satellite navigation devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parking Orbit
A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle follows a trajectory to the parking orbit, then coasts for a while, then engines fire again to enter the final desired trajectory. An alternative trajectory that is used on some missions is ''direct injection'', where the rocket fires continuously (except during staging) until its fuel is exhausted, ending with the payload on the final trajectory. This technique was first used by the Soviet Venera 1 mission to Venus in 1961. Reasons for use Geostationary spacecraft Geostationary spacecraft require an orbit in the plane of the equator. Getting there requires a geostationary transfer orbit with an apogee directly above the equator. Unless the launch site itself is quite close to the equator, it requires an impractically large amount of fuel to launch a spacecraft directly into such an orbit. Instead, the craft is placed with an upper stage in an inclined parking orbit. When the craft c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wireless World
''Electronics World'' (''Wireless World'', founded in 1913, and in October 1983 renamed ''Electronics & Wireless World'') is a technical magazine published by Datateam Business Media Ltd that covers electronics and RF engineering and is aimed at professional design engineers. It is produced monthly in print and digital formats. The editorial content of ''Electronics World'' covers the full range of electronics and RF industry activities including technology, systems, components, design, development tools, software, networking, communications tools and instrumentation. It encompasses a range of issues in the electronics and RF industry, from design through to product implementation. The features are contributed by engineers and academics in the electronics industry. The circulation is split between electronic design engineers, senior managers, and R&D professionals within areas such as communications, manufacturing, education and training, IT, medical, power, oil and gas. Histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Dish
A satellite dish is a dish-shaped type of parabolic antenna designed to receive or transmit information by radio waves to or from a communication satellite. The term most commonly means a dish which receives direct-broadcast satellite television from a direct broadcast satellite in geostationary orbit. History Parabolic or "dish" antennas had been in use as radio telescopes (beginning in 1937) and airplane tracking by the military (during WWII) long before the first artificial satellite was launched in 1957. The term ''satellite dish'' was coined in 1978 during the beginning of the satellite television industry, and came to refer to dish antennas that send and/or receive signals from communications satellites. Taylor Howard of San Andreas, California, adapted an ex-military dish in 1976 and became the first person to receive satellite television signals using it. The first satellite television dishes were built to receive signals on the C-band analog, and were very lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
