The Mobile User Objective System (MUOS for short) is a next-generation satellite communications system (SATCOM) owned and operated by the U.S. Navy that provides worldwide voice and data communications services to U.S. forces. The MUOS was developed for the U.S. Navy by Lockheed Martin, with involvement from aerospace and defense companies General Dynamics, Boeing and L3Harris Technologies. The system was declared fully operational in 2019.
The MUOS is the newest iteration of the Navy's ultra-high frequency (UHF) SATCOM system. The system was designed to be an upgrade from the UHF Follow-On (UFO) SATCOM system, which ha been the primary method of satellite communications for the military since 2000. Development on the MUOS began in 2004, after the U.S. Navy selected Lockheed Martin as the primary contractor for the system. The launch of the first MUOS satellite followed in 2012 and culminated with the launch of the fifth and final satellite in 2016.
While the Navy is the primary owner and operator of the MUOS, all U.S. military forces and some of their allies rely on the Navy's satellites for narrowband communications. The MUOS was designed to support a worldwide, multi-service population of UHF band users, as well as users who require mobility, high data rates and improved operational availability. The MUOS was developed to provide over sixteen times the system capacity of the UHF Follow-On. The system also features several new capabilities, including simultaneous crystal-clear voice, video, and mission data on a high-speed Internet Protocol-based system.
The MUOS network is made up of an initial configuration of four orbiting satellites, called MUOS 1-4, and four relay ground stations. The system also features an on-orbit spare satellite, MUOS-5, to ensure that the network is always available to provide secure communications to U.S. forces, while also supporting the legacy UHF system.
All MUOS satellites are equipped with a Wideband Code Division Multiple Access (WCDMA) payload, which provides over ten times the communications capacity over the UFO system. Additionally, each satellite is equipped with a legacy UHF payload, allowing the MUOS to be fully compatible with the UFO system and legacy terminals. The dual payload design was implemented in order to ensure a smooth transition from the UFO system to the MUOS.
The MUOS has also demonstrated the ability to provide secure voice and data communications in the Arctic, an area that has seen great increases in shipping traffic in recent years. MUOS communications can reach near the North Pole, far beyond the range of traditional geosynchronous satellites.
As of 2021, the U.S. Department of Defense (DoD) has spent over $7.4 billion to develop and produce the MUOS. While the system was declared fully operational in 2019, a 2021 congressional report from the U.S. Government Accountability Office (GAO) found that the DoD was not using the full capabilities of the MUOS. The report found the key reason to be delays in delivery of compatible radio terminals, preventing full adoption of the system. Additionally, the GAO found other challenges to the DoD's narrowband communications capabilities, including that U.S. forces' continued reliance on the legacy UFO system and that the current MUOS satellites in orbit had limited design lives.
In response to the report, the DoD said it was funding and developing plans to accelerate the delivery and procurement of the necessary terminals, and that it planned to buy and launch additional MUOS satellites without the legacy UHF payload in the future.