Celestri

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The Celestri Multimedia LEO System was a planned Low Earth orbit (LEO) satellite constellation, which was intended to offer global, low-latency broadband Internet services via Ka-band radio links [1] . It was planned by Motorola circa 1997-1998 as one of the earliest "Internet in the sky" constellations, and as a successor to the company's Iridium satellite constellation, but never built or launched.

The Celestri constellation was envisioned to consist of 63 operational satellites in 7 orbital planes, inclined at 48° with respect to the Equator, plus up to 7 in-orbit spares [1] . Satellites in each plane would follow circular orbits at an altitude of 1400 kilometers [1] . Each satellite was envisioned to contain all hardware and software needed to route traffic throughout the network, including Earth-to-space in the 28.6-29.1 GHz and 29.5-30.0 GHz bands, space-to Earth in the 18.8-19.3 GHz and 19.7-20.2 GHz bands, and space-to-space connections via optical inter-satellite links [1] . Satellites were expected to employ phased array antennas supporting 432 uplink beams and 260 downlink beams per satellite [2] , provided by Raytheon [3] , to communicate with Celestri ground stations, which would have equivalent antenna aperture sizes from 0.3 to 1 meter to support communications at rates from 2.048 to 155.52 Mbps.

Celestri's anticipated cost was $12.9 billion [4] . In May 1998, Motorola announced that it was dropping its plans for the Celestri system, and instead would invest $750 million in the rival Teledesic constellation [5] . The combined project was ultimately abandoned in 2003 [6] .

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References

  1. 1 2 3 4 Application for Authority to Construct, Launch and Operate the Celestri Multimedia LEO System, A Global Network of Non-Geostationary Communications Satellites Providing Broadband Services in the Ka Band, filed June 1997 with the Federal Communications Commission, Motorola Global Communications, Inc., Chandler, Arizona.
  2. ↑ Satellite Earth Stations and Systems (SES); Broadband satellite multimedia; Part 1: Survey on standardization objectives, ETSI Technical Report TR 101 374-1 V1.2.1 (1998-10), page 50.
  3. ↑ "Motorola to Give Raytheon Satellite-Antennae Contract", Wall Street Journal, October 30, 1997.
  4. ↑ "Motorola to build $12.9 billion global satellite network Celestri, a direct challenge to Teledesic, SkyBridge", Bloomberg News, June 18, 1997.
  5. ↑ "Motorola decides to drop Celestri satellite project, Will invest $750 million in rival Teledesic", Bloomberg News, May 22, 1998.
  6. ↑ de Selding, Peter B. "Teledesic Plays Its Last Card, Leaves the Game". Space News, July 14, 2003.
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