Teledesic

From Wikipedia, the free encyclopedia
Jump to: navigation, search
A typical Teledesic satellite design.

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 1995 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.[1] In 1997 the scheme was scaled back to 288 active satellites at 1400 km[2] and was later scaled back further in complexity and number of satellites as the projected market demand continued to decrease.

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.[3]

Teledesic was notable for gaining early funding from Microsoft (investing US$30 million for an 8.5% stake), Craig McCaw, Bill Gates, Paul Allen, and Saudi prince Alwaleed bin Talal, and for achieving allocation on the Ka-band frequency spectrum for non-geostationary services. Teledesic's merger with ICO Global Communications led to McCaw's companies taking control of ICO, which successfully launched one test satellite.

Description[edit]

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.

Teledesic T1[edit]

A demonstration satellite for the Teledesic constellation, originally labeled Broadband Advanced Technologies Satellite ("BATSAT"),[4] and later renamed "Teledesic T1", was launched on a Pegasus-XL launch vehicle in February 1998. The satellite differed in size and design from the anticipated satellite for the final constellation, but was designed to support two-way communications at speeds up to E1 rates in the 28.6-to-29.1-GHz band. The 120 kg satellite was placed in a 580 km × 535 km orbit at 97.7° inclination.[5]

References[edit]

  1. ^ 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.
  2. ^ 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.
  3. ^ 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.
  4. ^ Krebs, Gunter Dirk (4 March 2011). "BATSAT (Teledesic T1)". Gunter's Space Page. Retrieved 17 April 2011. 
  5. ^ SPACEWARN Bulletin (NASA's National Space Science Data Center/World Data Center) (532). 1 March 1998 http://nssdc.gsfc.nasa.gov/spacewarn/spx532.html |url= missing title (help). Retrieved 17 April 2011. 

External links[edit]