O3b FM17-FM20

O3b Networks Ltd. is a network communications service provider building and operating a medium Earth orbit (MEO) satellite constellation primarily intended to provide voice and data communications to mobile operators and Internet service providers, and is a wholly-owned subsidiary of SES S.A. The network combines the relatively large reach of satellite with high speed and medium latency to deliver satellite Internet services and mobile backhaul services to emerging markets. The name "O3b" stands for "Other 3 billion", referring to the population of the world where broadband Internet is not currently available. The satellites are deployed in a circular orbit along the equator at an altitude of 8,063 km (medium Earth orbit) at a velocity of approximately 18,918 km/h, each making 5 orbits a day. Due to problems with a component of the first four satellites launched, three of those four have been placed on standby. Each satellite is equipped with twelve fully steerable Ka-band antennas (two beams for gateways, ten beams for remotes) that use 4.3 GHz of spectrum (2 × 216 MHz per beam) with a proposed throughput of 1.6 Gbit/s per beam (800 Mbit/s per direction), resulting in a total capacity of 16 Gbit/s per satellite. Each beam's footprint measures 700 km (430 mi) in diameter. O3b claims a mouth-to-ear one-way latency of 179 milliseconds for voice communication and an end-to-end round-trip latency of 140 ms for data services. The maximum throughput per TCP connection is 2.1 Mbit/s. For maritime applications, O3b claims a round-trip latency of 140 ms and connectivity speeds of over 500 Mbit/s.