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TheMobile User Objective System (MUOS) is aUnited States Space Forcenarrowbandmilitarycommunications satellite system that supports a worldwide, multi-service population of users in theultra high frequency (UHF) band. The system provides increased communications capabilities to newer, smaller terminals while still supporting interoperability with legacy terminals. MUOS is designed to support users who require greater mobility, higherbit rates and improved operational availability. The MUOS was declared fully operational for use in 2019.[1]
The Mobile User Objective System (MUOS), through a constellation of five satellites (four operational satellites and one on-orbit spare), provides global narrowband connectivity to terminals, platforms, tactical operators and operations centers. The system replaces the slower and less mobile 1990s-eraUltra High Frequency Follow-On (UFO) satellite communication system. MUOS primarily serves theUnited States Department of Defense (DoD); although, international allies' use has been declined in the past.[2] Primarily for mobile users (e.g. aerial and maritime platforms, ground vehicles, and dismounted soldiers), MUOS extend users' voice, data, and video communications beyond their lines-of-sight at data rates up to 384 kbit/s.[3]
TheU.S. Navy's Communications Satellite Program Office (PMW 146) of the Program Executive Office (PEO) for Space Systems inSan Diego, is lead developer for the MUOS program.[4]Lockheed Martin Space is the prime system contractor and satellite designer for MUOS under U.S. Navy Contract N00039-04-C-2009, which was announced on 24 September 2004.[5][6] Key subcontractors includeGeneral Dynamics Mission Systems (Ground Transport architecture),Boeing (Legacy UFO and portions of the WCDMApayload) andHarris (deployable mesh reflectors). The program delivered five satellites, four ground stations, and a terrestrial transport network at a cost of US$7.34 billion.[7]
Each satellite in the MUOS constellation carries two payloads: a legacy communications payload to maintain Department of Defense narrowband communications during the transition to MUOS, and the advanced MUOSWideband Code Division Multiple Access (WCDMA) capability, according toNaval Information Warfare Systems Command (NAVWAR).
MUOS WCDMA radios can transmit simultaneous voice, video and mission data on anInternet Protocol-based system connected to military networks. MUOS radios operate from anywhere around the world at speeds comparable to 3G smartphones. MUOS radios can also work under dense cover, such as jungle canopies and urban settings. The MUOS operates as a global cellular service provider to support thewarfighter with moderncell phone-like capabilities, such asmultimedia. It converts a commercial third generation (3G)Wideband Code Division Multiple Access (WCDMA) cellular phone system to a military UHF SATCOM radio system usinggeosynchronous satellites in place ofcell towers. By operating in theUltra high frequency (UHF) frequency band, a lower frequency band than that used by conventional terrestrialcellular networks, the MUOS provides warfighters with thetactical ability to communicate in "disadvantaged" environments, such as heavily forested regions where higher frequency signals would be unacceptablyattenuated by the forest canopy. Connections may be set up on demand by users in the field, within seconds, and then released just as easily, freeing resources for other users. In alignment with more traditional military communications methods, pre-planned networks can also be established either permanently or per specific schedule using the MUOS' ground-based Network Management Center.
In addition to the cellular MUOS WCDMA payload, a fully capable and separate UFO legacy payload is incorporated into each satellite. The "legacy" payload extends the useful life of legacy UHF SATCOM terminals and enables a smoother transition to MUOS.
MUOS-1, after several weather delays, was launched into space successfully on 24 February 2012, at 22:15:00 UTC, carried by anAtlas Vlaunch vehicle flying in its 551 configuration.[8]
MUOS-2 was launched on schedule on 19 July 2013, at 13:00:00UTC aboard an Atlas V 551 (AV-040).[9]
MUOS-3 was launched on board a United Launch Alliance (ULA) Atlas V launch vehicle on 20 January 2015, fromCape Canaveral Air Force Station (CCAFS),Florida.[10][11]
MUOS-4 arrived at Cape Canaveral on 31 July 2015.[12] Weather conditions pushed back the launch, which was originally scheduled for on 31 August 2015, at 10:07 UTC.[13][14] The launch took place on 2 September 2015, at 10:18:00 UTC.[15]
MUOS-5 arrived at Cape Canaveral on 9 March 2016.[16] Launch was originally scheduled for on 5 May 2016, but due to an internal investigation into anAtlas V fuel system problem during theCygnus OA-6 launch on 22 March 2016, the scheduled date was pushed back.[17] The launch took place on 24 June 2016, at 14:30:00 UTC.[18] An "anomaly" aboard the satellite occurred a few days later, however, when it was still in aGeostationary Transfer Orbit (GTO), leaving it "Reconfigured into Safe Intermediate Orbit", or stranded in GTO.[19][20] Amateur observers tracked it in an orbit of approximately 15,240 × 35,700 km (9,470 × 22,180 mi) since 3 July 2016.[21] On 3 November 2016, the Navy announced that the satellite has finally reached operational orbit.
The four currently operational MUOS satellites are stationed at longitude 100° West (MUOS-1); 177° West (MUOS-2); 16° West (MUOS-3); and 75° East (MUOS-4).[22] MUOS-5 is a spare satellite now orbiting over the Continental US. They have a 5° orbital inclination. In the first few months after launch, the satellites were temporarily parked in a check-out position at longitude 172° West.[23]
The MUOS includes four ground station facilities.[3] Site selections were completed in 2007 with the signing of aMemorandum of Agreement (MOA) between the U.S. Navy and theAustralian Department of Defence. The four ground stations, each of which serves one of the four active satellites of the MUOS constellation will be located at: theAustralian Defence Satellite Communications Station atKojarena, Western Australia about 30 km east ofGeraldton, Western Australia;Naval Radio Transmitter Facility (NRTF) Niscemi about 60 km fromNaval Air Station Sigonella,Sicily,Italy; Naval SATCOM Facility, Northwest Chesapeake, Southeast Virginia at36°33′52″N76°16′14″W / 36.564393°N 76.270477°W /36.564393; -76.270477; and theNaval Computer and Telecommunications Area Master Station Pacific,Hawaii.
Construction of the ground station inItaly was halted for nearly half of 2012 by protesters concerned with health risks and environmental damage by radio waves. One scientific study "point[s] to serious risks to people and the environment, such as to prevent its realization in densely populated areas, like the one adjacent to the town ofNiscemi".[24] In spite of the controversy, the site at Niscemi was completed in anticipation of the launch of MUOS-4.
The MUOS waveform with completered/black operational capability was released in 2012. Until theJoint Tactical Radio System (JTRS) program cancellation in 2011, the JTRS program would provide the DoD terminals that can communicate with the MUOS WCDMAwaveform with a series of form-factor models. The JTRS Handheld, Manpack and Small Form Fit (HMS)AN/PRC-155 manpack built byGeneral Dynamics Mission Systems survived the wider JTRS program cancellation and has shipped several low rate of initial production (LRIP) units.Rockwell CollinsAN/ARC-210[25][26] airborne terminal andHarris CorporationAN/PRC-117G.[27][28] Manpack have also been certified for operation on the MUOS system.
Lockheed Martin and an industry team of radio vendors demonstrated extensive Arctic communications reach near theNorth Pole, believed to be the most northerly successful call to a geosynchronous satellite.[29] WCDMA calls to the far north will be increasingly important where there has been an increase in shipping, resource exploration and tourism without much improvement in secure satellite communications access. Based on these and continued tests, full coverage of theNorthwest Passage andNortheast Passage shipping lanes is expected. Several follow-on tests with high quality voice and data including streaming video have occurred in both theArctic andAntarctic, including a 2015 demonstration fromMcMurdo Station.[30]
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