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JSAT Corporation
JSAT Corporation (JSAT) was the first private Japanese satellite operator, which owned the JSAT satellites, as well as operated and partially owned the N-Star with NTT DoCoMo. Its origins can be traced to the funding of Japan Communications Satellite Company (JCSAT) and Satellite Japan Corporation in 1985. Both companies merged into Japan Satellite Systems Inc. in 1993. In 2000 the company was renamed as JSAT Corporation and was listed in the First Section of the Tokyo Stock Exchange. On September 1, 2008, the company was merged into the SKY Perfect JSAT Group. History With the opening of the Japanese satellite communications market to private investment, Japan Communications Satellite Company (JCSAT) and Satellite Japan Corporation were founded in 1985. In June of the same year, JCSAT awarded an order to Hughes Space and Communications for two identical satellites, JCSAT-1 and JCSAT-2, based on the spin-stabilized HS-393 satellite bus. JCSAT-1, the first commercial Japane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SKY Perfect JSAT Group
The SKY Perfect JSAT Group is a Japanese corporate group that claims to be Asia's largest satellite communication and multi-channel pay TV company. It owns the SKY PerfecTV! satellite broadcasting service and the SKY Perfect Well Think content studio, among other businesses. () is the holding company for the group, and holds 100% of the shares of , the group's main operating company. History JSAT The space and satellite business of the group dates to 1985, when its three predecessor companies were formed: Japan Communications Satellite Company (JCSC), Space Communications Corporation (SCC) and Satellite Japan Corporation (SJC). JCSAT-1, Japan's first private-sector communications satellite, was launched in 1989. JCSC and SJC merged in 1993, becoming Japan Satellite Systems, which changed its name to JSAT Corporation in 2000. JSAT was listed on the Tokyo Stock Exchange in the same year. SCC was acquired by the Sky Perfect JSAT Group in 2008. Sky PerfecTV The pay TV business ... [...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 collection ... [...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 german: Kurz-unten), 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ka Band
The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The band is called Ka, short for "K-above" because it is the upper part of the original NATO K band, which was split into three bands 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. The 30/20 GHz band is used in communications satellite uplinks in either the 27.5 GHz and 31 GHz bands, and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement. The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope. The designation "Ka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Band (IEEE)
The C band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 4.0 to 8.0 gigahertz (GHz). However, the U.S. Federal Communications Commission C band proceeding and auction, designated 3.7–4.2 GHz as C band. The C band is used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones, as well as some Radar and weather radar systems. Use in satellite communication The communications C band was the first frequency band that was allocated for commercial telecommunications via satellites. The same frequencies were already in use for terrestrial microwave radio relay chains. Nearly all C-band communication satellites use the band of frequencies from 3.7 to 4.2 GHz for their downlinks, and the band of frequencies from 5.925 to 6.425 GHz for their uplinks. Note that by using the band from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Band
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens (typically at 2.495 GHz). India's re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-STAR B
N-STAR b, was a geostationary communications satellite originally ordered by a consortium including NTT DoCoMo and JSAT Corporation, and later fully acquired by JSAT, which was merged into SKY Perfect JSAT Group. It was designed and manufactured by Space Systems/Loral on the SSL 1300 platform. It had a launch weight of , and a 10-year design life. Its payload is composed of 6 C-band, 11 Ka-band, 8 Ku-band and 1 S-band transponders. History N-Star was created as a joint venture between JSAT, Nippon Telegraph and Telephone (NTT), NTT Communications and NTT DoCoMo for the supply of these latter two ''WIDESTAR'' satellite telephone and data packet service. JSAT would handle the satellite side of business and NTT DoCoMo would operate the payload. Two identical satellites were ordered on 1992 from Space Systems Loral, N-STAR a and N-STAR b, for 1995 and 1996 on orbit delivery. They would be "switchboards in the sky" having S-band, C-band, Ka-band and Ku-band payload. N-STAR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-STAR A
N-STAR a, was a geostationary communications satellite originally ordered by a consortium including NTT DoCoMo and JSAT Corporation, and later fully acquired by JSAT, which was merged into SKY Perfect JSAT Group. It was designed and manufactured by Space Systems/Loral on the SSL 1300 platform. It had a launch weight of , and a 10-year design life. Its payload is composed of 6 C-band, 11 Ka-band, 8 Ku-band and 1 S-band transponders. History N-Star was created as a joint venture between JSAT, Nippon Telegraph and Telephone (NTT), NTT Communications and NTT DoCoMo for the supply of these latter two ''WIDESTAR'' satellite telephone and data packet service. JSAT would handle the satellite side of business and NTT DoCoMo would operate the payload. Two identical satellites were ordered on 1992 from Space Systems Loral, N-STAR a and N-STAR b, for 1995 and 1996 on orbit delivery. They would be "switchboards in the sky" having S-band, C-band, Ka-band and Ku-band payload. N-STAR a w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Systems Loral
SSL, formerly Space Systems/Loral, LLC (SS/L), of Palo Alto, California, is a wholly owned manufacturing subsidiary of Maxar Technologies. SSL designs and builds satellites and space systems for a wide variety of government and commercial customers. Its products include high-powered direct-to-home broadcast satellites, commercial weather satellites, digital audio radio satellites, Earth observation satellites and spot-beam satellites for data networking applications. History The company was founded as the Western Development Laboratories (WDL) of Philco (Philco-Ford since 1966). The Space Systems Division was made a stand-alone Division of Aeronutronic/Ford Aerospace/ and was acquired by Loral Corp. in 1990 for $715 million from Ford Motor Company, and renamed Space Systems/Loral. All other divisions of Ford Aerospace including Western Development Labs now located in San Jose, California, San Jose were also acquired by Loral at that time. In 2012 Space Systems/Loral was ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTT Communications
, or NTT Com, is a Japanese telecommunications company which operates an international network in over 190 countries/regions, with locations in more than 70 countries/regions. The company has approximately 5,500 employees (NTT Communications Group: 11,500 employees) as of March 2020. Its headquarters is located in the Otemachi Place West tower, Otemachi, Chiyoda, Tokyo. NTT Communications Corporation was founded in July 1999 as the wholly owned subsidiary of Nippon Telegraph & Telephone (NTT) Corp, and is one of the largest telecom companies in Japan and globally. NTT Communications provides network management, telecommunication services such as VPN, and communications technology (ICT) services including cloud, consulting, and managed services for companies and government agencies. History 1996-2005 Founding and early years In 1996, several new policies were issued for Telecommunications Law, and as a result of this policy changing NTT Communications Corporation was esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nippon Telegraph And Telephone
, commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan. Ranked 55th in Fortune Global 500, ''Fortune'' Global 500, NTT is the fourth largest telecommunications company in the world in terms of revenue, as well as the third largest publicly traded company in Japan after Toyota and Sony, as of June 2022. The company is incorporated pursuant to the NTT Law (). The purpose of the company defined by the law is to own all the shares issued by Nippon Telegraph and Telephone East Corporation (NTT East) and Nippon Telegraph and Telephone West Corporation (NTT West) and to ensure proper and stable provision of telecommunications services all over Japan including remote rural areas by these companies as well as to conduct research relating to the telecommunications technologies that will form the foundation for telecommunications. On 1 July 2019, NTT Corporation launched NTT Ltd., an $11 billion de facto holding company business consisting of 28 brand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commercial Titan III
The Commercial Titan III, also known as CT-3 or CT-III, was an American expendable launch system, developed by Martin Marietta during the late 1980s and flown four times during the early 1990s. It was derived from the Titan 34D, and was originally proposed as a medium-lift expendable launch system for the US Air Force, who selected the Delta II instead. Development was continued as a commercial launch system, and the first rocket flew in 1990. Due to higher costs than contemporary rockets such as the Ariane 4, orders were not forthcoming, and the CT-3 was retired in 1992. The Commercial Titan III differed from the Titan 34D in that it had a stretched second stage, and a larger payload fairing to accommodate dual satellite payloads. All four launches occurred from LC-40 at Cape Canaveral Air Force Station. The first carried two communications satellites, Skynet 4A and JCSAT-2, and was launched at 00:07 UTC on 1 January 1990, which was 19:07 local time on 31 December 1989, maki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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