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Molniya (satellite)
The Molniya ( rus, Молния, p=ˈmolnʲɪjə, a=Ru-молния.ogg, "Lightning") series satellites were military and communications satellites launched by the Soviet Union from 1965 to 2004. These satellites used highly eccentric elliptical orbits known as Molniya orbits, which have a long dwell time over high latitudes. They are suited for communications purposes in polar regions, in the same way that geostationary satellites are used for equatorial regions. There were 164 Molniya satellites launched, all in Molniya orbits with the exception of Molniya 1S which was launched into geostationary orbit for testing purposes. History In the early 1960s, when Europe and America were establishing geostationary communication satellites, the Russians found these orbits unsuitable. They were limited in the amount of rocket power available and it is extremely energy intensive to both launch a satellite to 40,000 km, and change its inclination to be over the equator, especially whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a Federation, federal union of Republics of the Soviet Union, fifteen national republics; in practice, both Government of the Soviet Union, its government and Economy of the Soviet Union, its economy were highly Soviet-type economic planning, centralized until its final years. It was a one-party state governed by the Communist Party of the Soviet Union, with the city of Moscow serving as its capital as well as that of its largest and most populous republic: the Russian Soviet Federative Socialist Republic, Russian SFSR. Other major cities included Saint Petersburg, Leningrad (Russian SFSR), Kyiv, Kiev (Ukrainian Soviet Socialist Republic, Ukrainian SSR), Minsk (Byelorussian Soviet Socialist Republic, Byelorussian SSR), Tas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesetsk Cosmodrome
Plesetsk Cosmodrome ( rus, Космодром «Плесецк», r=Kosmodrom "Plesetsk", p=kəsmɐˈdrom plʲɪˈsʲet͡sk) is a Russian spaceport located in Mirny, Arkhangelsk Oblast, about 800 km north of Moscow and approximately 200 km south of Arkhangelsk, the cosmodrome dates to 1957. Originally developed as an ICBM site for the R-7 missile, it also served for numerous satellite launches using the R-7 and other rockets. Its high latitude makes it useful only for certain types of launches, especially the Molniya orbits, so for much of the site's history it functioned as a secondary location, with most orbital launches taking place from Baikonur, in the Kazakh SSR. With the end of the Soviet Union, Baikonur became a foreign territory, and Kazakhstan charged $115 million usage fees annually. Consequently, Plesetsk has seen considerably more activity since the 2000s. Overview Plesetsk () is used especially for military satellites placed into high inclinatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites Using The KAUR Bus
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. 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 is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by propuls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Inventions
This timeline of Russian Innovation encompasses key events in the history of technology in Russia, from the Grand Duchy of Moscow up to the Russian Federation. The entries in this timeline fall into the following categories: * indigenous inventions, like airliners, AC transformers, radio receivers, television, artificial satellites, ICBMs * uniquely Russian products, objects and events, like Saint Basil's Cathedral, Matryoshka dolls, Russian vodka * products and objects with superlative characteristics, like the Tsar Bomba, the AK-47, and the Typhoon-class submarine * scientific and medical discoveries, like the periodic law, vitamins and stem cells This timeline includes scientific and medical discoveries, products and technologies introduced by various peoples of Russia and its predecessor states, regardless of ethnicity, and also lists inventions by naturalized immigrant citizens. Certain innovations achieved internationally may also appear in this timeline in ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Equipment Of The Cold War
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded drumbea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites Of The Soviet Union
Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inquiry studying them. There are many disagreements about its precise definition. John Peters argues that the difficulty of defining communication emerges from the fact that communication is both a universal phenomenon and a specific discipline of institutional academic study. One definitional strategy involves limiting what can be included in the category of communication (for example, requiring a "conscious intent" to persuade). By this logic, one possible definition of communication is the act of developing meaning among entities or groups through the use of sufficiently mutually understood signs, symbols, and semiotic conventions. An important distinction is between verbal communication, which happens through the use of a language, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Military Spacecraft
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national republics; in practice, both its government and its economy were highly centralized until its final years. It was a one-party state governed by the Communist Party of the Soviet Union, with the city of Moscow serving as its capital as well as that of its largest and most populous republic: the Russian SFSR. Other major cities included Leningrad (Russian SFSR), Kiev (Ukrainian SSR), Minsk ( Byelorussian SSR), Tashkent (Uzbek SSR), Alma-Ata (Kazakh SSR), and Novosibirsk (Russian SFSR). It was the largest country in the world, covering over and spanning eleven time zones. The country's roots lay in the October Revolution of 1917, when the Bolsheviks, under the leadership of Vladimir Lenin, overthrew the Russian Provisional Government ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler's Laws Of Planetary Motion
In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler between 1609 and 1619, describe the orbits of planets around the Sun. The laws modified the heliocentric theory of Nicolaus Copernicus, replacing its circular orbits and epicycles with elliptical trajectories, and explaining how planetary velocities vary. The three laws state that: # The orbit of a planet is an ellipse with the Sun at one of the two foci. # A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. # The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit. The elliptical orbits of planets were indicated by calculations of the orbit of Mars. From this, Kepler inferred that other bodies in the Solar System, including those farther away from the Sun, also have elliptical orbits. The second law helps to establish that when a planet is closer to the Sun, it travels faster. The thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidereal Day
Sidereal time (as a unit also sidereal day or sidereal rotation period) (sidereal ) is a timekeeping system that astronomers use to locate celestial objects. Using sidereal time, it is possible to easily point a telescope to the proper coordinates in the night sky. In short, sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars", or more correctly, relative to the March equinox. Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same sidereal time. This is similar to how the time kept by a sundial ( Solar time) can be used to find the location of the Sun. Just as the Sun and Moon appear to rise in the east and set in the west due to the rotation of Earth, so do the stars. Both Solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis: solar time following the Sun while, roughly speaking, sidereal time f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodal Period
The nodal period (or draconic period) of a satellite is the time interval between successive passages of the satellite through either of its orbital nodes, typically the ascending node. This type of orbital period applies to artificial satellites, like those that monitor weather on Earth, and natural satellites like the Moon. It is distinct from the sidereal period, which measures the period with respect to reference stars seemingly fixed onto a spherical background, since the location of a satellite's nodes precess over time. For example, the nodal period of the Moon is 27.2122 days (one draconic month), while its sidereal period is 27.3217 days (one sidereal month). Near-Earth satellites The oblate figure of the Earth has important effects of the orbits of near-Earth satellites. An expression for the nodal period () of a near circular orbit, such that the eccentricity () is almost but not equal to zero, is the following: : T_n = \frac \left( 1 - \frac - \frac \right) wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frozen Orbit
In orbital mechanics, a frozen orbit is an orbit for an artificial satellite in which natural drifting due to the central body's shape has been minimized by careful selection of the orbital parameters. Typically, this is an orbit in which, over a long period of time, the satellite's altitude remains constant at the same point in each orbit. Changes in the inclination, position of the apsis of the orbit, and eccentricity have been minimized by choosing initial values so that their perturbations cancel out., which results in a long-term stable orbit that minimizes the use of station-keeping propellant. Background and motivation For most spacecraft, changes to orbits are caused by the oblateness of the Earth, gravitational attraction from the sun and moon, solar radiation pressure, and air drag. These are called "perturbing forces". They must be counteracted by maneuvers to keep the spacecraft in the desired orbit. For a geostationary spacecraft, correction maneuvers on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oblate Spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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