OneWeb #18

The 18th flight dedicated to the OneWeb high-speed Internet constellation. The initial constellation consists of 648 satellites. Later, the constellation could be expanded to more than 900 satellites depending on demand. OneWeb is expected to begin customer demonstrations in 2022, then provide a global, 24-hour service in 2022/2023. Each satellite in the constellation weighs 147.7 kg. They are powered by Russian ion engines, manufactured by OKB-Fakel, and have two solar panels for their power supply. The first generation of satellites, operating on a quasi-polar orbit (1 200 km x 86.4°), cannot perform inter-satellite communication, and can only be used near a ground relay station. The satellites will provide user service in the Ku-band, communicating in the microwave range of frequencies in the 12-18 GHz portion of the electromagnetic spectrum. The satellites use a technique called "progressive pitch" in which the satellites are slightly turned to avoid interference with Ku-band satellites in geostationary orbit. The user terminal antenna on the ground will be a phased array antenna measuring approximately 36 by 16 cm and will provide Internet access at 50 megabits/second downlink bandwidth (almost certainly less uplink, but this number remains hard to pin down). The satellites will be designed to comply with orbital debris-mitigation guidelines for removing satellites from orbit and, for low-orbit satellites, assuring that they reenter the Earth's atmosphere within 25 years of retirement.