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Intelsat 23
Intelsat 23 is a communications satellite run by Intelsat which will provide communications services for the Americas, Western Europe and Africa. It is in a geosynchronous orbit located at 53° west and will replace Intelsat 707. It was built by Orbital Sciences and has a designed life of 15 years. Satellite Intelsat 23 is one of a series of Intelsat communications satellites which are in geosynchronous orbit so that they are always located over the same part of the earth. It will be located over the equator at 53° west and is intended to replace Intelsat 707, which was launched in 1996. The satellite was built by Orbital Sciences using their GEOstar-2 bus. It has 24 C band circular polarized transponders covering the Americas and Western Europe, and 15 linear polarized Ku band transponders covering Latin America. The satellite has 32 C band transponders and 19 Ku band transponders in total to provide for redundancy. Both antennae are 2.5m x 2.7m. Launch Intelsat 23 was ... [...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] |
Orbital Sciences
Orbital Sciences Corporation (commonly referred to as Orbital) was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other government customers. In 2014, Orbital merged with Alliant Techsystems (ATK) to create a new company called Orbital ATK, which in turn was purchased by Northrop Grumman in 2018. Orbital was headquartered in Dulles, Virginia and publicly traded on the New York Stock Exchange with the ticker symbol ORB. Orbital's primary products were satellites and launch vehicles, including low Earth orbit (LEO), geosynchronous Earth orbit and planetary spacecraft for communications, remote sensing, scientific and defense missions; ground- and air-launched launch vehicles that delivered satellites into orbit; missile defense systems that were used as interceptor and target vehicles; and human-rated space systems for Earth orbit, lunar and other missions. Orbital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Launched By Proton Rockets
A spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket). On a sub-orbital spaceflight, a space vehicle enters space and then returns to the surface without having gained sufficient energy or velocity to make a full Earth orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit (space stations) only, whereas those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research are sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intelsat Satellites
Intelsat S.A. (formerly Intel-Sat, Intelsat) is a Luxembourgish-American multinational satellite services provider with corporate headquarters in Luxembourg and administrative headquarters in Tysons, Virginia, United States. Originally formed as International Telecommunications Satellite Organization (''ITSO'', or Intelsat), from 1964 to 2001, it was an intergovernmental consortium owning and managing a constellation of communications satellites providing international telecommunications and broadcast services. In March 2023, rival satellite operator SES confirmed that it was in talks about a merger with Intelsat but in June 2023, it was announced that these discussions had ended. On 30 April 2024, SES announced that an agreement had been reached to acquire Intelsat for US$3.1 billion, with the transaction expected to close in the second half of 2025. As of June 2022, Intelsat operated a fleet of 52 communications satellites which was then one of the world's largest fleets. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telkom-3
Telkom-3 is an Indonesian communications satellite which failed to reach its target orbit due to a launch failure on 6 August 2012. It was built by ISS Reshetnev for Indonesian telecommunications provider PT Telekomunikasi Indonesia. It was based on the Ekspress-1000H bus and had 32 C band transponders and 16 Ku-band transponders. It was due to be located in geosynchronous orbit at 118° East above the equator. The satellite reentered the atmosphere and was destroyed on 5 February 2021. Launch Telkom-3 was launched along with Ekspress-MD2 by a Proton-M rocket with Briz-M upper stage on 6 August 2012 at 19:31:00 UTC. The satellites were launched from Site 81/24 at Baikonur Cosmodrome in Kazakhstan. The first three stages of the Proton launched worked as expected and the satellites were attached to the Briz-M upper stage which would transfer them into geosynchronous orbit. The Briz-M undertakes a series of four burns with coasting stages to do this. The third burn wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ekspress-MD2
Ekspress-MD2 was a Russian communications satellite which was lost due to a launch failure on 6 August 2012. Equipped with eight C-band transponders and 1 L-band transponder, it was intended to be located in geostationary orbit at a longitude of 145° East. It was the second Ekspress-MD satellite to be launched, following Ekspress-MD1 in 2009. Launch Ekspress-MD2 was launched atop a Proton-M launch vehicle with a Briz-M upper stage on 6 August 2012 at 19:31:00 UTC. The Indonesian Telkom-3 satellite was also carried aboard the launch vehicle. Launch occurred from Site 81/24 at the Baikonur Cosmodrome in Kazakhstan. The first three stages of the Proton launched worked as expected and the satellites were attached to the Briz-M upper stage which would transfer them into geosynchronous orbit. The Briz-M undertakes a series of four burns with coasting stages in order to do this. The third burn was due to be 18 minutes long but the engines cut out after 7 seconds, leaving th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Transfer Orbit
In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit (GEO). Satellites that are destined for geosynchronous orbit (GSO) or GEO are often put into a GTO as an intermediate step for reaching their final orbit. 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. Manufacturers of launch vehicles often advertise the amount of payload the vehicle can put into GTO. Background Geostationary and geosynchronous orbits are very desirable for many communication and Earth observation satellites. However, the delta-v, and therefore financial, cost to send a spacecraft to such orbits is very high due to their high orbital radius. A GTO is an intermedia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-orbital
A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the surface of the gravitating body from which it was launched. Hence, it will not complete one orbital revolution, will not become an artificial satellite nor will it reach escape velocity. For example, the path of an object launched from Earth that reaches the Kármán line (about – above sea level), and then falls back to Earth, is considered a sub-orbital spaceflight. Some sub-orbital flights have been undertaken to test spacecraft and launch vehicles later intended for orbital spaceflight. Other vehicles are specifically designed only for sub-orbital flight; examples include crewed vehicles, such as the X-15 and SpaceShipTwo, and uncrewed ones, such as ICBMs and sounding rockets. Flights which attain sufficient velocity to go into low Earth orbit, and then de-orbit before completing their first full orbit, are not considered sub-orbital. Examples o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redundancy (engineering)
In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance, such as in the case of GNSS receivers, or multi-threaded computer processing. In many safety-critical systems, such as fly-by-wire and hydraulic systems in aircraft, some parts of the control system may be triplicated, which is formally termed triple modular redundancy (TMR). An error in one component may then be out-voted by the other two. In a triply redundant system, the system has three sub components, all three of which must fail before the system fails. Since each one rarely fails, and the sub components are designed to preclude common failure modes (which can then be modelled as independent failure), the probability of all three failing is calculated to be extraordinarily small; it is often outweighed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ku Band
The Ku band () is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally ), because it is the lower part of the original NATO K band, which was split into three bands (Ku, K, and Ka) because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz, (1.35 cm) which made the center unusable for long range transmission. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002. Ku band is primarily used for satellite communications, most notably the downlink used by direct broadcast satellites to broadcast satellite television, and for specific applications such as NASA's Tracking Data Relay Satellite used for International Space Station (ISS) communications and SpaceX Starlink satellites. Ku band satellites are also used for backhauls and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Polarization
In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. The term ''linear polarization'' (French: ''polarisation rectiligne'') was coined by Augustin-Jean Fresnel in 1822.A. Fresnel, "Mémoire sur la double réfraction que les rayons lumineux éprouvent en traversant les aiguilles de cristal de roche suivant les directions parallèles à l'axe", read 9 December 1822; printed in H. de Senarmont, E. Verdet, and L. Fresnel (eds.), ''Oeuvres complètes d'Augustin Fresnel'', vol. 1 (1866), pp.731–51; translated as "Memoir on the double refraction that light rays undergo in traversing the needles of quartz in the directions parallel to the axis", , 2021 (open access); §9. See '' polarization'' and ''plane of polarization'' for more information. The orientation of a linearly polarized electromagn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponders
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite, a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. Satellite/broadcast communications A communications satellite’s channels are called transponders because each is a separate transceiver or repeater. With digital video data compression and multiplexing, several video and audio channels may travel through a single tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
