|
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 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] |
JSAT (satellite Constellation)
The JSAT constellation is a Communication satellite, communication and Satellite broadcasting, broadcasting satellite constellation formerly operated by JSAT Corporation and currently by SKY Perfect JSAT, SKY Perfect JSAT Group. It has become the most important commercial constellation in Japan, and fifth in the world. It has practically amalgamated all private satellite operators in Japan, with only Broadcasting Satellite System Corporation, B-SAT left as a local competitor. JSAT began in 1985, with the opening by the Government of Japan, of the communication markets in Japan and the founding of JSAT Corporation, Japan Communications Satellite Company, JSAT Corporation, Satellite Japan Corporation, SKY Perfect JSAT, Space Communications Corporation. It grew by own investment, mergers and acquisitions of the parent companies. As of August 2016, it includes the fleets of three previously mentioned companies, Horizons Satellite and NTT DoCoMo and the DSN (satellite network), DSN mili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Launched In 1995
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 space prob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellites Using The SSL 1300 Bus
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellations. Bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites In Geostationary Orbit
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether unintentional or failed transmissions are included and whether communication not only transmits meaning but also creates it. Models of communication are simplified overviews of its main components and their interactions. Many models include the idea that a source uses a coding system to express information in the form of a message. The message is sent through a channel to a receiver who has to decode it to understand it. The main field of inquiry investigating communication is called communication studies. A common way to classify communication is by whether information is exchanged between humans, members of other species, or non-living entities such as computers. For human communication, a central contrast is between verbal and non-verbal communication. Verbal communication involves the exchange of messages in linguistic form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JCSAT-5A
JCSAT-5A or N-STAR d, known as JCSAT-9 before launch, is a geostationary communications satellite operated by SKY Perfect JSAT Group (JSAT), which was designed and manufactured by Lockheed Martin on the A2100 platform. Satellite description The spacecraft was designed and manufactured by Lockheed Martin on the A2100-AX satellite bus. It had a launch mass of and a 12-year design life. It would provide communications services throughout Japan and Asia and for NTT DoCoMo.As most satellites based on the A2100-AX platform, it uses a LEROS-1C liquid apogee engine (LAE) for orbit raising. Its solar panels span when fully deployed, and, with its antennas in fully extended configurations it is wide. Its payload consists of eight 54 MHz and twelve 36 MHz Ku-band transponders, twenty 36 MHz C-band transponders, and one S-band beam. The Ku-band transponders have a TWTA output power of 110 watts, a C-band of 45 watts, and a S beam of 130 watts. History On 30 April 2003 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTT Communications
is a Japanese telecommunications company owned by Nippon Telegraph and Telephone Corporation. It operates an international network across over 190 countries and regions, with locations in more than 70 countries and regions. The company has approximately 5,500 employees (NTT Communications Group: 11,500 employees) as of March 2020. Its headquarters are located in the Otemachi Place West tower, Otemachi, Chiyoda, Tokyo. NTT Communications Corporation was founded in July 1999 as a subsidiary of Nippon Telegraph and Telephone Corporation. NTT Communications provides network management, telecommunication services such as VPN, and communications technology (ICT) services including cloud, consulting, and managing services for companies and government agencies. History 1996–2005 Founding and early years In 1996, several new policies were issued for the Telecommunications Law, and as a result of this policy change, NTT Communications Corporation was established in July 1999. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nippon Telegraph And Telephone
(NTT) is a Japanese telecommunications holding company headquartered in Tokyo, Japan. Ranked 55th in ''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. In 2023, the company was ranked 56th in the Forbes Global 2000. NTT was the world's largest company by market capitalization in the late 1980s, and remained among the world's top 10 largest companies by market capitalization until the burst of the Dot-com bubble in the early 2000s. The company traces its origin to the national telegraph service established in 1868, which came under the purview of the Ministry of Communications in the 1880s. In 1952, the telegraph and telephone services were spun off as the government-owned . Under Prime Minister Yasuhiro Nakasone, the company was privatised in 1985 along with the Japanese National Railways and the Japan Tobacco a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder (satellite Communications)
A communications satellite's transponder is the series of interconnected units that form a communications channel between the receiving and the transmitting antennas. It is mainly used in satellite communication to transfer the received signals. A transponder is typically composed of: * an input band-limiting device (an input band-pass filter), * an input low-noise amplifier (LNA), designed to amplify the signals received from the Earth station (normally very weak, because of the large distances involved), * a frequency translator (normally composed of an oscillator and a frequency mixer) used to convert the frequency of the received signal to the frequency required for the transmitted signal, * an output band-pass filter, * a power amplifier (this can be a traveling-wave tube or a solid-state amplifier). Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a Bandwidth (signal processing), bandwidth of tens of megahertz. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Japan ... [...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] |
