NTT DoCoMo, Inc., Japan's premier mobile communications company, provides wireless voice and data communications to tens of millions of subscribers. NTT DoCoMo is the creator of W-CDMA air interface technology, the new de facto global industry standard, as well as the groundbreaking mobile i-mode service.
Satellite mobile communications service covers all of Japan including the country's isolated islands by four beams from the geostationary N-STAR satellite. As satellite communication is less affected by geophysical disasters or weather conditions, it provides highly reliable service even during emergencies.
The N-STAR satellite mobile communications system was developed on the principle of sharing the hardware of terrestrial systems in terms of technology. Through integration with the ground network, it provides an efficient and economic system that includes the necessary minimum functions and allows for effective frequency usage and the efficient consumption of satellite power. Moreover, we have also developed various innovations in order to maximize the number of satellite circuits and provide stable service.
SSL built two advanced telecommunications satellites for JSAT and NTT DoCoMo of Japan that carry some of the most versatile payloads in orbit. Each features five communications payloads operating in four frequency bands. The N-STAR spacecraft, built by Space Systems/LORAL of Palo Alto, Calif., is a three-axis, body-stabilized FS-1300 series design which will weigh approximately 3,600 kg (7,920 pounds) at launch. Each satellite has five communications systems operating on four different frequency bands: S, C, Ku and Ka band. The N-STAR satellites will provide fixed and mobile telecommunications services for a design life of over 10 years over the Pacific Ocean. N-STAR will provide telecommunications coverage for the Japanese Islands and its territorial waters.
The N-STAR a and N-STAR b satellites were slated to be launched in 1995 by an Ariane 4 from the Kourou Space Center in French Guiana. The two satellites would be operated by Nippon Telegraph and Telephone Corporation (NTT), Japan's leading telecommunications operator. Commenting on this latest contract, Arianespace Chairman and CEO Charles Bigot said: "We are extremely pleased at having been selected by Space Systems/LORAL, one of the world's leading satellite manufacturers, on behalf of Japan's largest telecommunications company, NTT. This choice is a great honor for our company and further confirms our customer's confidence in the reliability and regularity of Arianespace's launch services. In Japan, in particular, all telecommunications companies have selected Europe's Ariane launcher for their satellites, and we are very proud to make such a significant contribution to the development of space-based communications in Japan." The Arianespace backlog now stood at 33 satellites to be launched, worth about 14.5 billion FF, i.e. about U.S. $2.76 billion.
Launched in 1995 and 1996, the N-Star satellites provide a variety of fixed and mobile services. N-STAR-A was a Japanese geostationary communications spacecraft that was launched 1995-08-29 by an Ariane 4-P rocket from the Kourou Space Center in French Guiana. The 3.4 ton spacecraft entered a parking longitude of 132 deg E. The NStar satellite was damaged in transit to Arianespace's launch site in Kourou, French Guiana. The NStar bird took PanAmSat's former launch date on Aug. 23, if repairs to the damaged bird could be made in time [they were]. The NStar satellite needed repairs because a wall from the container used to protect the satellite during transit fell on the Space Systems/Loral-built bird during a flight between the United States and French Guiana.
N-Star-B was a Japanese geosynchronous spacecraft launched 1996-02-05 by an Ariane rocket from the Kourou Space Center in French Guiana. The 3,400 kg spacecraft was expected to provide voice and TV broadcasts to Japan and neighboring regions. It was reported in December 2002 that JCSat-9 would replace N-Star A and N-Star B. It was reported in January 2008 that N-Star 2 had been moved into a disposal orbit.
The N-STAR satellite communications network includes two N-STAR satellites and their respective satellite base stations and satellite local switches as exclusive systems. Those sections beyond satellite local switches are shared with the terrestrial mobile communications network. Accordingly, the control method for call processing is basically the same as that for the terrestrial-type portable and automobile telephone systems.
The satellite maritime mobile telephone service, which was started at the end of March 1996, substantially extended the existing service area to some 200 nautical miles (370 km) offshore, and also eliminated dead zones where communications had been blocked by outlying islands and other obstacles. Reflecting improvements brought about by digitization, it has now become possible to convey information to a maximum of 100 recipients at one time using simultaneous communications.
N-Star 3 [aka N-STAR c ] is a Japanese geostationary communications spacecraft that was launched (along with Stellat 5) by an Ariane 5 rocket from Kourou at 23:22 UT on 5 July 2002. The 1,625 kg (with fuel), 1,400 W triaxially-stabilized satellite provided mobile telephone, data transfer and maritime communications to Japan and neighboring area through its S- and C-band transponders after parking over 135 deg-E longitude.
N-STAR c is furthering NTTís vision of providing wireless service for a multitude of applications including mobile telephony, data transfer and maritime communications. N-STAR c provides an improved signal to users, allowing better voice quality and smaller mobile phones for the Japanese users. The N-STAR c telecommunications satellite, designed and built by a Lockheed Martin Commercial Space Systems/Orbital Sciences team for NTT DoCoMo, Inc., was shipped in June 2002 from the production facilities in Newtown, Pa. to Kourou, French Guiana, where it was readied for a July launch.
N-STAR c operated in the S-band frequency band with a C-band feeder link from its orbital location at 136 degrees East longitude. N-STAR c is optimized for a 10-year life on-orbit, and will provide mobile telephony and data transfer services to Japan and its surrounding waters. For N-STAR c, Lockheed Martin served as prime contractor, providing the entire payload, which was integrated onto the Orbital Sciences Corporation's STAR-2 bus. The satellite was assembled and integrated at Lockheed Martin facilities in Newtown, Pa.
N-STAR c is based on Orbitalís highly successful Geosynchronous Earth Orbit (GEO) communications satellites which are able to accommodate all types of commercial communications payloads and are compatible with all major commercial launchers. The companyís GEOStar product line includes the GEOStar-2 design, which is optimized for smaller satellite missions that can support up to 5.0 kilowatts of payload power. Orbital has also developed the higher-power GEOStar-3 spacecraft design, delivering the next increment of payload power for applications between 5.0 and 8.0 kilowatts, allowing Orbital to offer its innovative and reliable satellite design to the medium-class of communications satellites.
NSTAR d is also known as JCSAT-5A, formerly JCSAT-9. NTT-DoCoMo operates the S-band payload and a part of the C-band payload as N-Star d to replace the N-Star a satellite.
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