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BSAT-1b
BSAT-1b was a geostationary communications satellite designed and manufactured by Hughes (now Boeing) on the HS-376 platform. It was originally ordered and operated by the Broadcasting Satellite System Corporation (B-SAT). It was used as backup of BSAT-1a to broadcast television channels for NHK and WOWOW over Japan. It had a pure Ku band payload and operated on the 110°E longitude until it was replaced, along its twin BSAT-1a, by BSAT-3a. Satellite description The spacecraft was designed and manufactured by Hughes on the HS-376 satellite bus. This spin-stabilized platform had two main sections. One, the spinning section, was kept rotating at 50 rpm to maintain attitude, and a despun section that was used by the payload to maintain radio coverage. The spinning section included the Star-30BP Apogee kick motor, most of the attitude control, the power subsystem and the command and telemetry subsystems. The despun section contained the communications payload, including the an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BSAT-1a
BSAT-1a was a geostationary communications satellite designed and manufactured by Hughes (now Boeing) on the HS-376 platform. It was originally ordered and operated by the Broadcasting Satellite System Corporation (B-SAT). It was used as the main satellite to broadcast television channels for NHK and WOWOW over Japan. It had a pure Ku band payload and operated on the 110°E longitude until it was replaced, along its backup BSAT-1b, by BSAT-3a. On 3 August 2010, it was decommissioned and placed on a graveyard orbit. Satellite description The spacecraft was designed and manufactured by Hughes on the HS-376 satellite bus. This spin-stabilized platform had two main sections. One, the spinning section, was kept rotating at 50 rpm to maintain attitude, and a despun section that was used by the payload to maintain radio coverage. The spinning section included the Star-30BP Apogee kick motor, most of the attitude control, the power subsystem and the command and telemetry subsystems. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcasting Satellite System Corporation
The Broadcasting Satellite System Corporation (B-SAT) is a Japanese corporation established in April 1993 to procure, manage and lease transponders on communications satellites. Its largest stockholder, owning 49.9%, is NHK, the Japan Broadcasting Corporation. In 1994, it was ranked by ''Space News'' as the world's 19th largest fixed satellite operator. Satellite fleet The B-SAT fleet has an extensive history. This is an overview of the satellites. Former satellites These satellites were managed by Broadcasting Satellite System Corporation but are now decommissioned. BSAT-1a BSAT-1a was an HS-376 based satellite with 4 active plus 4 spares Ku-band transponders. It was successfully launched on 16 April 1997 aboard an Ariane 44LP along Thaicom 3. BSAT-1b BSAT-1b was an HS-376 based satellite with 4 active plus 4 spares Ku-band transponders. It was successfully launched on 28 April 1998 aboard an Ariane 44P along Nilesat 101. BSAT-2a BSAT-2a was manufactured by O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HS-376
The Boeing 376 (sometimes referred to as the BSS-376, and previously as the HS-376) is a communications satellite bus introduced in 1978 by Hughes Space and Communications Company. It was a spin-stabilized bus that the manufacturer claims was the first standardized platform. Design The satellite bus was designed and manufactured by Hughes. This spin-stabilized platform had two main sections. The spinning section was kept rotating at 50 rpm to maintain attitude, and a despun section was used by the payload to maintain radio coverage. The spinning section included the apogee kick motor, most of the attitude control, the power subsystem and the command and telemetry subsystems. The despun section contained the communications payload, including the antennas and transponders. The stock version had a launch mass of , a mass of after reaching geostationary orbit and an 8 to 10-year design life. When stowed for launch, its dimensions were in height and in diameter. With its sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BSAT-2a
BSAT-2a, was a geostationary communications satellite operated by B-SAT which was designed and manufactured by Orbital Sciences Corporation on the STAR-1 platform. It was stationed on the 110° East orbital slot along its companion BSAT-2c from where they provided redundant high definition direct television broadcasting across Japan. Satellite description BSAT-2a was designed and manufactured by Orbital Sciences Corporation on the STAR-1 satellite bus for B-SAT. It had a launch mass of , a dry mass of , and a 10-year design life. As all four STAR-1 satellites, it had a solid rocket Star 30CBP apogee kick motor for orbit raising, plus of propellant for its liquid propellant station keeping thrusters. It measured when stowed for launch. Its dual wing solar panels can generate 2.6 kW of power at the beginning of its design life, and span when fully deployed. It has a single Ku band payload with four active transponders plus four spares with a TWTA outpu ... [...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; 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star 30
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its total mass is the main factor determining its evolution and eventual fate. A star shines for most of its active life d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Bus
A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-derived satellites are usually customized to customer requirements, for example with specialized sensors or transponders, in order to achieve a specific mission. They are commonly used for geosynchronous satellites, particularly communications satellites, but are also used in spacecraft which occupy lower orbits, occasionally including low Earth orbit missions. Examples Some satellite bus examples include: * Boeing DS&S 702 * Lockheed Martin Space Systems A2100 * Alphabus * INVAP ARSAT-3K * Airbus D&S Eurostar * ISRO's I-1K, I-2K, I-3K, I-4K, I-6K, and Indian Mini Satellite bus * NASA Ames MCSB * SSL 1300 * Orbital ATK GEOStar * Mitsubishi Electric DS2000 * Spacecraft bus of the James Webb Space Telescope * SPUTNIX ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin-stabilized Satellite
Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle attitude requires sensors to measure vehicle orientation, actuators to apply the torques needed to orient the vehicle to a desired attitude, and algorithms to command the actuators based on (1) sensor measurements of the current attitude and (2) specification of a desired attitude. The integrated field that studies the combination of sensors, actuators and algorithms is called guidance, navigation and control (GNC). Overview A spacecraft's attitude must typically be stabilized and controlled for a variety of reasons. It is often needed so that the spacecraft high-gain antenna may be accurately pointed to Earth for communications, so that onboard experiments may accomplish precise pointing for accurate collectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrionics
Astrionics is the science and technology of the development and application of electronic systems, subsystems, and components used in spacecraft. The electronic systems on-board a spacecraft are embedded systems and include attitude determination and control, communications, command and telemetry, and computer systems. Sensors refers to the electronic components on board a spacecraft. For engineers one of the most important considerations that must be made in the design process is the environment in which the spacecraft systems and components must operate and endure. The challenges of designing systems and components for the space environment include more than the fact that space is a vacuum. Attitude determination and control Overview One of the most vital roles electronics and sensors play in a mission and performance of a spacecraft is to determine and control its attitude, or how it is oriented in space. The orientation of a spacecraft varies depending on the mission. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apogee Kick Motor
An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit. For a satellite launched from the Earth, the rocket firing is done at the highest point of the transfer orbit, known as the apogee. An apogee kick motor is used, for example, for satellites launched into a geostationary orbit. As the vast majority of geostationary satellite launches are carried out from spaceports at a significant distance away from Earth's equator, the carrier rocket often only launches the satellite into an orbit with a non-zero inclination approximately equal to the latitude of the launch site. This orbit is commonly known as a "geostationary transfer orbit" or a "geosynchronous transfer orbit". The satellite must then provide thrust to bring forth the needed delta v to reach a geostationary orbit. This is typically done with a fixed on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical cir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
