Engineering:I-4 satellite
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]
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 bandwidth to a user, and background uses the excess bandwidth available to a satellite to eventually transmit data.[4]
See also
- Inmarsat-4 F1
- Inmarsat-4 F3
- Inmarsat-4A F4
References
- ↑ 1.0 1.1 "ESA/Inmarsat agreement to improve satellite mobile phone and data services" (in en). https://www.esa.int/Applications/Connectivity_and_Secure_Communications/ESA_Inmarsat_agreement_to_improve_satellite_mobile_phone_and_data_services.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 "Alphasat and the I-4s". https://www.inmarsat.com/about-us/about-usour-satellites/inmarsat-4/.
- ↑ Peter B. de Selding (October 8, 2010). "ESA and DARPA To Study Use of Inmarsat-4 for Space Data Relay". Space News. https://spacenews.com/esa-and-darpa-study-use-inmarsat-4-space-data-relay/.
- ↑ 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. https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1239&context=smallsat. Retrieved March 16, 2025.
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