Mobile User Objective System

Overview

The Mobile User Objective System, or MUOS, relies on a group of five satellites—four active and one backup in orbit—to offer worldwide narrowband communication for terminals, platforms, field operators, and command centers. It updates the older, slower Ultra High Frequency Follow-On system from the 1990s, which had less mobility.

MUOS is mainly used by the U.S. Department of Defense, though allied nations have sometimes been denied access. Built for users on the move, like aircraft, ships, ground vehicles, and soldiers on foot, it provides voice, data, and video links beyond line-of-sight, reaching speeds up to 384 kbit/s. The U.S. Navy’s Communications Satellite Program Office in San Diego manages development.

Lockheed Martin Space serves as the lead contractor and satellite designer, with key partners including General Dynamics Mission Systems, Boeing, and Harris. Each satellite holds two payloads: one for older communications to ease the transition, and the advanced MUOS Wideband Code Division Multiple Access system.

Launches

MUOS-1 finally launched on 24 February 2012 at 22:15:00 UTC aboard an Atlas V 551, after weather delays. MUOS-2 followed on schedule on 19 July 2013 at 13:00:00 UTC, also on an Atlas V 551. MUOS-3 lifted off from Cape Canaveral on 20 January 2015. MUOS-4 arrived at Cape Canaveral on 31 July 2015; its launch, originally set for 31 August 2015 at 10:07 UTC, was delayed by weather and occurred on 2 September 2015 at 10:18:00 UTC.

MUOS-5 reached Cape Canaveral on 9 March 2016. Its planned 5 May 2016 launch was postponed due to an investigation into an Atlas V fuel issue from the Cygnus OA-6 mission, finally launching on 24 June 2016 at 14:30:00 UTC. An anomaly left MUOS-5 stranded in geostationary transfer orbit; the Navy announced on 3 November 2016 that it had reached operational orbit.

MUOS ground stations

The MUOS relies on four ground stations, each linked to one of its four active satellites. Site selection ended in 2007 after a U.S. Navy and Australian Department of Defence agreement. One station is near Geraldton, Western Australia; another near Niscemi, Sicily; a third in southeast Virginia; and a fourth in Hawaii.

In 2012, construction in Italy stopped for nearly six months due to protests over radio wave health and environmental risks. A study cited serious dangers to people and nature in dense areas like Niscemi. Despite opposition, the Italian site was finished before MUOS-4 launched.

Arctic and Antarctic capabilities

An industry team led by Lockheed Martin placed what is believed to be the most northerly call ever made to a geosynchronous satellite, reaching near the North Pole. This WCDMA capability matters because Arctic shipping, resource extraction, and tourism are growing, yet secure satellite communications remain limited. Based on these and subsequent tests, the system is expected to cover both the Northwest and Northeast Passage shipping lanes fully. Later demonstrations have delivered high-quality voice, data, and streaming video in both polar regions, including a 2015 test from Antarctica’s McMurdo Station.

Did You Know?

• The four operational MUOS satellites are stationed at longitudes 100° West, 177° West, 16° West, and 75° East.
• The MUOS waveform with complete red/black operational capability was released in 2012.