I-4 satellite

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The Inmarsat-4 satellites, or I-4 satellites are a satellite constellation operated by Inmarsat. [1] [2] They provide the Inmarsat BGAN, [1] [2] FleetBroadband, [2] and SwiftBroadband communications networks. [2] They operate on the L band [2] everywhere on Earth, except in polar regions. [3]

Contents

According to Inmarsat, their launch created the first global 3G mobile network. [2]

The first three were launched between 2005 and 2008. [2] They had a mass (at launch) of 5.96 tonnes, and were intended to last 13 years [2] The dimensions of the main body comparable to a double-decker bus at 7m x 2.9m x 2.3m. [2] Including the solar arrays, however, the wingspan is 45 meters, closer to the size of a soccer pitch. [2] The reflectors are 9 meters wide. [2]

Data services

Both streaming and background data service is provided, where streaming allocates a fixed guaranteed bandwith to a user, and background uses the excess bandwith available to a satellite to eventually transmit data. [4]

See also

References

  1. 1 2 "ESA/Inmarsat agreement to improve satellite mobile phone and data services". ESA. Retrieved 11 March 2025.
  2. 1 2 3 4 5 6 7 8 9 10 11 "Alphasat and the I-4s". Inmarsat. Archived from the original on 24 March 2018.
  3. ↑ Peter B. de Selding (8 October 2010). "ESA and DARPA To Study Use of Inmarsat-4 for Space Data Relay". Space News. Retrieved 16 March 2025.
  4. ↑ Christian Lenz; Chris McCormick; Rob Goldsmith; Eyal Trachtman (2010). "Real-time, near global, low earth orbit communications using geostationary INMARSAT BGAN system as a relay". 24th Annual AIAA/USU Conference on Small Satellites. Retrieved 16 March 2025.
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