|
CZ-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. It is dedicated for launching spacecraft into GTO GTO may refer to: Entertainment * '' Great Teacher Onizuka'', a manga, anime, live-action series, and film * GameTable Online, a game portal Music bands * GTO (band), an Australian band * The GTOs, an American girl group * Giraffe Ton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YF-20
The YF-20 is a Chinese liquid-fuel rocket engine burning N2O4 and UDMH in a gas generator cycle. It is a basic engine which when mounted in a four engine module forms the YF-21. The high altitude variation is known as the YF-22 is normally paired with the YF-23 vernier to form the YF-24 propulsion module for second stages. New versions when used individually for booster applications are called YF-25. Versions The basic engine has been used since the Feng Bao 1 rocket and has been the main propulsion of the Long March 2, Long March 3 and Long March 4 families. * YF-20: Core engine. Flown originally on the Feng Bao 1 and Long March 2A. * YF-20A: Core engine. * YF-20B (a.k.a. DaFY5-1): Core engine, also used on the boosters. * YF-20C: Core engine, also used on the boosters. * YF-20D: Core engine, also used on the boosters. * YF-20E: Core engine, also used on the boosters. * YF-22: Upper stage version with enlarged nozzle are ratio. Flown originally on the Feng Bao 1 second s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March Rocket
The Long March rockets are a family of expendable launch system rockets operated by the China Aerospace Science and Technology Corporation. The rockets are named after the Chinese Red Army's 1934–35 Long March military retreat during the Chinese Civil War. The Long March series has performed more than 350 launches, including missions to low-Earth orbit, sun-synchronous orbit, geostationary transfer orbit, and Earth-moon transfer orbit. The new-generation carrier rockets, Long March 5, Long March 6, Long March 7, Long March 11, and Long March 8, have made their maiden flights. Among them, the Long March 5 has a low-Earth orbit carrying capacity of 25,000 kilograms, and a geosynchronous transfer orbit carrying capacity of 14,000 kilograms. History China used the Long March 1 rocket to launch its first satellite, Dong Fang Hong 1 (lit. "The East is Red 1"), into low Earth orbit on 24 April 1970, becoming the fifth nation to achieve independent launch capability. Early launch ... [...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] |
Carrier Rocket
A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to large operating costs. An orbital launch vehicle must lift its payload at least to the boundary of space, approximately and accelerate it to a horizontal velocity of at least . Suborbital vehicles launch their payloads to lower velocity or are launched at elevation angles greater than horizontal. Practical orbital launch vehicles are multistage rockets which use chemical propellants such as solid fuel, liquid hydrogen, kerosene, liquid oxygen, or Hypergolic propellants. Launch vehicles are classified by their orbital payload capacity, ranging from small-, medium-, heavy- to super-heavy lift. M ... [...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; it creates a communication channel between a source transmitter and a 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 and so are obstructed by the curve of the Earth. The purpose of communications satel ... [...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 Navigatio ... [...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] |
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 rifl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit
In celestial mechanics, an orbit 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 understanding of the exact mechanics ... [...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 re ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
