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Long March 3A
The Long March 3A (), also known as the Chang Zheng 3A, CZ-3A and LM-3A, is a Chinese orbital carrier rocket design. It is a 3-stage rocket, and is usually used to place communications satellites and Beidou navigation satellites into geosynchronous transfer orbits. It has formed the basis of the Long March 3B, which is a heavier version with four liquid booster rockets. Launches Long March 3A rockets have been launched from Launch Areas 2 and 3 at the Xichang Satellite Launch Center. List of launches Technical data LM-3A is a 3-stage launch vehicle developed on the basis of LM-3 and LM-2C. Its third stage is powered by cryogenic propellants: liquid hydrogen and liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an applica .... It is dedicated for launching spacecraft into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submachine Gun
A submachine gun (SMG) is a magazine-fed, automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to describe its design concept as an automatic firearm with notably less firepower than a machine gun (hence the prefix " sub-"). As a machine gun must fire rifle cartridges to be classified as such, submachine guns are not considered machine guns. The submachine gun was developed during World War I (1914–1918) as a close quarter offensive weapon, mainly for trench raiding. At its peak during World War II (1939–1945), millions of SMGs were made for use by regular troops, clandestine commandos and partisans alike. After the war, new SMG designs appeared frequently.Military Small Arms Of The 20th Century. Ian Hogg & John Weeks. Krause Publications. 2000. p93 However, by the 1980s, SMG usage decreased. Today, submachine guns have been largely replaced by assault rifles, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YF-75
The YF-75 is a liquid cryogenic rocket engine burning liquid hydrogen and liquid oxygen in a gas generator cycle. It is China's second generation of cryogenic propellant engine, after the YF-73, which it replaced. It is used in a dual engine mount in the H-18 third stage of the Long March 3A, Long March 3B and Long March 3C launch vehicles. Within the mount, each engine can gimbal individually to enable thrust vectoring control. The engine also heats hydrogen and helium to pressurize the stage tanks and can control the mixture ratio to optimize propellant consumption. Development Given the upward trend on geosynchronous communication satellite's mass and size, a program to develop an engine more powerful than the YF-73 was started by 1982. The proper development of the engine started in 1986 and leveraged the experience of the YF-73. It flew for the first time in 1994. By September 2013, it had accumulated 12 start up and 3,000 seconds of firing time without malfunction. By 2006 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ChinaSat 22
ChinaSat () is the brand name of communications satellites operated by China Satellite Communications. History In 2007, a joint venture China Direct Broadcast Satellite was formed to run the brand ChinaSat. It was a joint venture of state-owned companies China Satellite Communications, China Orient Telecommunications Satellite and Sino Satellite Communications. The latter was controlled by China Aerospace Science and Technology Corporation (CASC). However, China Satellite Communications was changed from a direct subsidiary of the State-owned Assets Supervision and Administration Commission of the State Council (SASAC) to a direct subsidiary of CASC in 2009, the joint venture was dissolved and Sino Satellite Communications became a subsidiary of China Satellite Communications. The brand ChinaSat was previously operated by China Telecommunications Broadcast Satellite Corporation, which was owned by China's Ministry of Posts and Telecommunications. China Telecommunications Bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ChinaSat 6
ChinaSat () is the brand name of communications satellites operated by China Satellite Communications. History In 2007, a joint venture China Direct Broadcast Satellite was formed to run the brand ChinaSat. It was a joint venture of state-owned companies China Satellite Communications, China Orient Telecommunications Satellite and Sino Satellite Communications. The latter was controlled by China Aerospace Science and Technology Corporation (CASC). However, China Satellite Communications was changed from a direct subsidiary of the State-owned Assets Supervision and Administration Commission of the State Council (SASAC) to a direct subsidiary of CASC in 2009, the joint venture was dissolved and Sino Satellite Communications became a subsidiary of China Satellite Communications. The brand ChinaSat was previously operated by China Telecommunications Broadcast Satellite Corporation, which was owned by China's Ministry of Posts and Telecommunications. China Telecommunications Bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Transfer Orbit
A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellite, Satellites that are destined for geosynchronous orbit, geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step for reaching their final orbit. A GTO is highly Elliptic orbit, elliptic. Its perigee (closest point to Earth) is typically as high as low Earth orbit (LEO), while its apogee (furthest point from Earth) is as high as geostationary (or equally, a geosynchronous) orbit. That makes it a Hohmann transfer orbit between LEO and GSO. Larson, Wiley J. and James R. Wertz, eds. Space Mission Design and Analysis, 2nd Edition. Published jointly by Microcosm, Inc. (Torrance, CA) and Kluwer Academic Publishers (Dordrecht/Boston/London). 1991. While some geostationary orbit, GEO satellites are launched direct to that orbit, often the launch vehicle lacks the power to put both the rocket and the satellite into that orbit. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dong Fang Hong 3
Dong or DONG may refer to: Places * Dong Lake, or East Lake, a lake in China * Dong, Arunachal Pradesh, a village in India * Dong (administrative division) (동 or 洞), a neighborhood division in Korea Persons *Queen Dong (1623–1681), princess consort of Koxinga and mother of Zheng Jing *Empress Dong (Ran Min's wife), wife of Ran Min, emperor of Chinese state Ran Wei *Empress Dowager Dong (died 189), empress dowager during Han dynasty *Dǒng (surname) or 董, a Chinese surname *Dōng (surname) or 東, a Chinese surname Entertainment * ''Dong'' (film) (东), a documentary film by Jia Zhangke. * Dong Open Air, a heavy metal festival in Germany. * D!NG Channel (previously Do Online Now Guys, or DONG), a YouTube channel and spin off of Vsauce, Vsauce2, Vsauce3, and Wesauce Other uses * Dong people, an ethnic minority group of China * Dong language (China) * Dong language (Nigeria) * Vietnamese đồng, a unit of currency * Ørsted (company), a Danish energy company formerly kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highly Elliptical Orbit
A highly elliptical orbit (HEO) is an elliptic orbit with high eccentricity, usually referring to one around Earth. Examples of inclined HEO orbits include Molniya orbits, named after the Molniya Soviet communication satellites which used them, and Tundra orbits. Such extremely elongated orbits have the advantage of long dwell times at a point in the sky during the approach to, and descent from, apogee. Bodies moving through the long apogee dwell appear to move slowly, and remain at high altitude over high-latitude ground sites for long periods of time. This makes these elliptical orbits useful for communications satellites. Geostationary orbits cannot serve high latitudes because their elevation above the horizon from these ground sites is too low. Sirius Satellite Radio used inclined HEO orbits, specifically the Tundra orbits, to keep two satellites positioned above North America while another satellite quickly sweeps through the southern part of its 24-hour orbit. The longit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shijian
Shijian (, abbr. "SJ") is a series of satellites built and operated by the People's Republic of China. Some Shijian-series satellites have drawn significant concerns from the United States government and space observers who cite unannounced launches, undisclosed sub-satellites deployed in orbit, unusual orbital maneuvers, and demonstrated rendezvous proximity operations (RPO) including the close inspection and towing of other satellites. Little is known about the series and what differentiates it from other experimental satellite series launched by China such as the Chuangxin () series or Shiyan () series. The China Aerospace Studies Institute of the United States Air Force asserts that Shiyan-series satellites play an earlier role in the systems development process testing various new technologies on a single bus while Shijan-series satellites are used to develop operational best practices and optimize the technologies previously tested on Shiyan-series satellites. In this regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chang Zheng 3a Launch
Chang may refer to: People Surname * Chang (surname), the romanization of several separate Chinese surnames * Chang or Jang (Korean name), romanizations of the Korean surname Given name * Chang Bunker () (1811–1874), one of the original Siamese twins * Liu Chang (other) * Chang, the younger brother in the children's book ''Tikki Tikki Tembo'' * Chang (Star Trek), a Klingon general from the film ''Star Trek VI: The Undiscovered Country'' * Chang Koehan, a Korean character from ''The King of Fighters'' * Benjamin Chang, a Chinese character from ''Community'' Pseudonym * Chang (director) (born Yoon Hong-seung, 1975), a South Korean film director Ethnography * Chang Naga, a tribe of Tuensang in Nagaland, India * Chang language, spoken by the Chang Naga Places * Chang, Bhiwani, a village in the Indian state of Haryana * Chang, Iran, a village in Hormozgan Province of Iran Other uses * Chang, chaang, or chhaang, a traditional alcoholic barley drink of Tibe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosynchronous Transfer Orbit
A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellites that are destined for geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step for reaching their final orbit. A GTO is highly elliptic. Its perigee (closest point to Earth) is typically as high as low Earth orbit (LEO), while its apogee (furthest point from Earth) is as high as geostationary (or equally, a geosynchronous) orbit. That makes it a Hohmann transfer orbit between LEO and GSO. Larson, Wiley J. and James R. Wertz, eds. Space Mission Design and Analysis, 2nd Edition. Published jointly by Microcosm, Inc. (Torrance, CA) and Kluwer Academic Publishers (Dordrecht/Boston/London). 1991. While some GEO satellites are launched direct to that orbit, often the launch vehicle lacks the power to put both the rocket and the satellite into that orbit. Instead extra fuel is added to the satellite, the launch vehicle la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation Satellite
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few centimetres to metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to a high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). One set of critical vulnerabilities in satellite communications are the signals that govern positioning, navigation and timing (PNT). Failure to properly secure these transmissions could not only disrupt satellite networks but wreak havoc on a host of dependent s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beidou Navigation System
The BeiDou Navigation Satellite System (BDS; ) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and also known as BeiDou-1, consisted of three satellites which, beginning in 2000, offered limited coverage and navigation services, mainly for users in China and neighboring regions. BeiDou-1 was decommissioned at the end of 2012. The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, became operational in China in December 2011 with a partial constellation of 10 satellites in orbit. Since December 2012, it has been offering services to customers in the Asia-Pacific region. In 2015, China launched the third generation BeiDou system (BeiDou-3) for global coverage. The first BDS-3 satellite was launched on 30 March 2015. On 27 December 2018, BeiDou Navigation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
