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Strela (satellite)
Strela (russian: Стрела, for ''Arrow'') is a Russian (previously Soviet) military communications satellite constellation operating in low Earth orbit. These satellites operate as mailboxes (" store-and-forward"): they remember the received messages and then resend them after the scheduled time, or by a command from the Earth. Some sources state the satellites are capable of only three months of active operation, but through coordination with others they can serve for about five years. The satellites are used for transmission of encrypted messages and images. History The first three satellites, Kosmos 38 (reentered 8 November 1964), Kosmos 39 (reentered 17 November 1964) and Kosmos 40 (reentered 17 November 1964), were launched on 18 August 1964. Five different types of Strela satellites have been launched, designated Strela-1 (1964-1965), Strela-1M (1970-1992), Strela-2 (1965-1968), Strela-2M (1970-1994), and Strela-3 (1985-2010). Strela satellites are also used for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NPO Prikladnoi Mekhaniki
JSC Information Satellite Systems Reshetnev (russian: Информационные спутниковые системы имени академика М. Ф. Решетнёва, Informatsionnye sputnikovye systemy imeny akademika M. F. Reshetnyova) is a Russian satellite manufacturing company. It is based in the closed city of Krasnoyarsk-26 (today called Zheleznogorsk), Krasnoyarsk Krai near the city of Krasnoyarsk. The company was formerly called NPO PM (short for NPO Prikladnoi Mekhaniki or Applied Mechanics Science-Production Association; NPO stands for Nauchno-proizvodstvennoye obyedineniye, Scientific Production Association). History The company was founded in 1959 by as the Eastern office of OKB-1. During its history, it has built 27 different space systems and over a thousand individual satellites. In particular, the company was responsible for designing the GLONASS satellite navigation system. After the dissolution of the Soviet Union, the company lost most of its s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Store-and-forward
Store and forward is a telecommunications technique in which information is sent to an intermediate station where it is kept and sent at a later time to the final destination or to another intermediate station. The intermediate station, or node in a networking context, verifies the integrity of the message before forwarding it. In general, this technique is used in networks with intermittent connectivity, especially in the wilderness or environments requiring high mobility. It may also be preferable in situations when there are long delays in transmission and variable and high error rates, or if a direct, end-to-end connection is not available. Modern store and forward networking * Store and forward originates with delay-tolerant networks. No real-time services are available for these kinds of networks. * Logistical Networking is a scalable form of store and forward networking that exposes network-embedded buffers on intermediate nodes and allows flexible creation of services ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites
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 high frequency radio waves used for telecommunications links travel by Line-of-sight propagation, line of sight and so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Satellites
A military satellite is an artificial satellite used for a military purpose. The most common missions are intelligence gathering, navigation and military communications. The first military satellites were photographic reconnaissance missions. Some attempts were made to develop satellite based weapons but this work was halted in 1967 following the ratification of international treaties banning the deployment of weapons of mass destruction in orbit. As of 2013, there are 950 satellites of all types in Earth orbit. It is not possible to identify the exact number of these that are military satellites partly due to secrecy and partly due to dual purpose missions such as GPS satellites that serve both civilian and military purposes. As of December 2018 there are 320 known military or dual-use satellites in the sky, half of which are owned by the US, followed by Russia, China and India (13). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium 33
Iridium 33 was a communications satellite launched by Russia for Iridium Communications. It was launched into low Earth orbit from Site 81/23 at the Baikonur Cosmodrome at 01:36 UTC on 14 September 1997, by a Proton-K rocket with a Block DM2 upper stage. The launch was arranged by International Launch Services (ILS). It was operated in Plane 3 of the Iridium satellite constellation, with an ascending node of 230.9°. Mission Iridium 33 was part of a commercial communications network consisting of a constellation of 66 LEO spacecraft. The system uses L-Band to provide global communications services through portable handsets. Commercial service began in 1998. The system employs ground stations with a master control complex in Landsdowne, Virginia, a backup in Italy, and a third engineering center in Chandler, Arizona. Spacecraft The spacecraft was 3-axis stabilized, with a hydrazine propulsion system. It had 2 solar panels with 1-axis articulation. The system employed L-Band ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2009 Satellite Collision
On February 10, 2009, two communications satellites—the active commercial Iridium 33 and the derelict Russian military Kosmos 2251—accidentally collided at a speed of and an altitude of above the Taymyr Peninsula in Siberia. It was the first time a hypervelocity collision occurred between two satellites – until then, all accidental hypervelocity collisions had involved a satellite and a piece of space debris. Spacecraft Kosmos 2251 was a Russian Strela military communications satellite owned by the Russian Space Forces. It was launched on a Russian Cosmos-3M carrier rocket on June 16, 1993. It had been deactivated prior to the collision, and remained in orbit as space debris. Iridium33 was a US-built commercial satellite and was part of the Iridium constellation of 66 communications satellites owned by Iridium Communications. It was launched on September 14, 1997, atop a Russian Proton rocket. Collision The collision occurred at 16:56 UTC and destroyed both the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 2251
Kosmos-2251 (russian: Космос-2251 meaning ''Cosmos 2251''), was a Russian Strela-2M military communications satellite. It was launched into Low Earth orbit from Site 132/1 at the Plesetsk Cosmodrome at 04:17 UTC on 16 June 1993, by a Kosmos-3M carrier rocket.· The Strela satellites had a lifespan of 5 years, and the Russian government reported that Kosmos-2251 ceased functioning in 1995. Russia was later criticised by ''The Space Review'' for leaving a defunct satellite in a congested orbit, rather than deorbiting it. In response, Russia noted that they were (and are) not required to do so under international law. In any case, the KAUR-1 satellites had no propulsion system, which is usually required for deorbiting. Destruction At 16:56 UTC on 10 February 2009, it collided with Iridium 33 (1997-051C), an Iridium satellite, in the first major collision of two satellites in Earth orbit. The Iridium satellite, which was operational at the time of the collision, was destro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bundesheer
The Austrian Armed Forces (german: Bundesheer, lit=Federal Army) are the combined military forces of the Republic of Austria. The military consists of 22,050 active-duty personnel and 125,600 reservists. The military budget is 0.74% of national GDP or €2.85 billion. History Between 1918 and 1920, the Austrian semi-regular army was called ("People's Defence"), and fought against Yugoslavian army units occupying parts of Carinthia. It has been known as "Bundesheer" since then, except when Austria was a part of Nazi Germany (1938–1945; see Anschluss). The Austrian Army did develop a defence plan in 1938 against Germany, but politics prevented it from being implemented. World War II role of the "Bundesheer": *Elements of Austrian Army became 9th Panzer Division (Wehrmacht) *Elements of Austrian Army became 44th Infantry Division (Wehrmacht) *4th Austrian Division became the 45th Infantry Division (Wehrmacht) In 1955, Austria issued its Declaration of Neutrality, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 40
The cosmos (, ) is another name for the Universe. Using the word ''cosmos'' implies viewing the universe as a complex and orderly system or entity. The cosmos, and understandings of the reasons for its existence and significance, are studied in cosmologya broad discipline covering scientific, religious or philosophical aspects of the cosmos and its nature. Religious and philosophical approaches may include the cosmos among spiritual entities or other matters deemed to exist outside the physical universe. Etymology The philosopher Pythagoras first used the term ''kosmos'' ( grc, κόσμος, Latinized ''kósmos'') for the order of the universe. Greek κόσμος "order, good order, orderly arrangement" is a word with several main senses rooted in those notions. The verb κοσμεῖν (''κοσμεῖν'') meant generally "to dispose, prepare", but especially "to order and arrange (troops for battle), to set (an army) in array"; also "to establish (a government or regime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 39
The cosmos (, ) is another name for the Universe. Using the word ''cosmos'' implies viewing the universe as a complex and orderly system or entity. The cosmos, and understandings of the reasons for its existence and significance, are studied in cosmologya broad discipline covering scientific, religious or philosophical aspects of the cosmos and its nature. Religious and philosophical approaches may include the cosmos among spiritual entities or other matters deemed to exist outside the physical universe. Etymology The philosopher Pythagoras first used the term ''kosmos'' ( grc, κόσμος, Latinized ''kósmos'') for the order of the universe. Greek κόσμος "order, good order, orderly arrangement" is a word with several main senses rooted in those notions. The verb κοσμεῖν (''κοσμεῖν'') meant generally "to dispose, prepare", but especially "to order and arrange (troops for battle), to set (an army) in array"; also "to establish (a government or regime)" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 38
The cosmos (, ) is another name for the Universe. Using the word ''cosmos'' implies viewing the universe as a complex and orderly system or entity. The cosmos, and understandings of the reasons for its existence and significance, are studied in cosmologya broad discipline covering scientific, religious or philosophical aspects of the cosmos and its nature. Religious and philosophical approaches may include the cosmos among spiritual entities or other matters deemed to exist outside the physical universe. Etymology The philosopher Pythagoras first used the term ''kosmos'' ( grc, κόσμος, Latinized ''kósmos'') for the order of the universe. Greek κόσμος "order, good order, orderly arrangement" is a word with several main senses rooted in those notions. The verb κοσμεῖν (''κοσμεῖν'') meant generally "to dispose, prepare", but especially "to order and arrange (troops for battle), to set (an army) in array"; also "to establish (a government or regime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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