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Teledesic
Teledesic was a company founded in the 1990s to build a commercial broadband satellite constellation for Internet services. Using low-earth orbiting satellites small antennas could be used to provide uplinks of as much as 100 Mbit/second and downlinks of up to 720 Mbit/second. The original 1994 proposal was extremely ambitious, costing over US$9 billion and originally planning 840 active satellites with in-orbit spares at an altitude of 700 km.〔(In the Matter of Teledesic Corporation: Application for Authority to Construct, Launch, and Operate a Low Earth Orbit Satellite System in the Domestic and International Fixed Satellite Service ). File Nos. 22-DSS-P/LA-94, 43-SAT-AMEND-95, 127 SAT-AMEND-95. Federal Communications Commission, March 14, 1997. (Initial Teledesic FCC authorization.) Accessed March 15, 2010.〕 In 1997, the plan was scaled back to 288 active satellites at 1400 km〔(In the Matter of Teledesic LLC Application for Authority to Construct, Launch, and Operate a Ka-band Satellite System in the Fixed-Satellite Service ). File Nos. 22-DSS-P/LA-94, 43-SAT-AMEND-95, 127 SAT-AMEND-95, 195-SAT-ML-97. Federal Communications Commission, January 31, 2001. (Teledesic FCC Modification.) Accessed March 15, 2010.〕
The commercial failure of the similar Iridium and Globalstar ventures (composed of 66 and 48 operational satellites, respectively) and other systems, along with bankruptcy protection filings, were primary factors in halting the project, and Teledesic officially suspended its satellite construction work on October 1, 2002.〔de Selding, Peter B. "(Teledesic Plays Its Last Card, Leaves the Game )". Space News, July 14, 2003. Accessed March 15, 2010, via the Internet Archive.〕
Teledesic was notable for gaining early funding from cellular pioneer Craig McCaw, Microsoft co-founder Bill Gates, and Saudi prince Alwaleed bin Talal, and for achieving a radio frequency spectrum allocation in the Ka-band for non-geostationary fixed satellite services.
==Description==
The satellites were three-axis stabilized with a faceted antenna on the bottom and a large articulated solar panel on top. The spacecraft was designed to be compatible with over 20 different launch vehicles to permit launch option flexibility. The satellites were to be launched into a 700 km circular, near polar (98.2 deg) sun synchronous orbit. The initial rollout was to include 12 orbit planes with 24 spacecraft in each plane. The antenna footprint for each satellite was to be about 700 km.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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