UHF Follow-On satellite

The Ultra high frequency (UHF) satellites primarily served tactical users. UFO provided almost twice as many channels as FLTSATCOM and has about 10% more power per channel. THe satellites were built by Boeing Integrated Defense Systems (formerly Hughes Space and Communications Company) and were based on the 601 series of communications satellites. The Extremely high frequency (EHF) package on satellites four through eleven have an Earth coverage beam and a steerable five-degree spot beam that enhances its tactical use. The EHF capability also allows the UFO network to connect to the strategic Milstar system. Satellites eight, nine and ten also carry the Global Broadcast Service antennas that operate in the Ka-band. The Atlas was the launch vehicle of choice; however, space shuttle compatibility existed. The UFO bus and payload weigh . The solar panels spans and produces 2,500 watts at the end of the planned 14-year lifetime. The UHF system supports stationary and mobile users including manportable, ships, submarines, aircraft and other mobile terminals. The UFO Follow-On system is scheduled for replacement by the Mobile User Objective System (MUOS). == Block Upgrades ==

Block 1 satellites had UHF and SHF communications. Block 2 satellites, starting with UHF 4, added extremely high frequency package with 11 channels. Block 3 satellites replaced the SFH communications with Ka-band transponders. Block 4 satellite incorporated a digital UHF receiver and two additional UHF channels. == Launch ==

First launch of the UFO took place on 25 March 1993, with constellation completion dependent on replacement needs for the aging FLTSATCOM constellation. == Table of Satellites ==