2601:985:D01:36F6:0:0:0:DE: /* Overview */

2025-04-30T12:42:10Z

Overview

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{{Short description|US Space Force communications satellite system}}
{{Use American English|date=May 2021}}
{{Use dmy dates|date=May 2021}}

[[File:MUOS new.jpg|thumb|upright=1.0|right|Artist's concept of a MUOS satellite]]
[[File:U. S. Navy's Mobile User Objective System at the Vertical Integration Facility at Cape Canaveral's Space Launch Complex-41 on August 19, 2015 - 150815-N-VC599-023 (22851646176) (cropped).jpg|thumb|U. S. Navy's Mobile User Objective System logo at the Vertical Integration Facility of Cape Canaveral's Space Launch Complex-41 on August 19, 2015]]
The '''Mobile User Objective System''' (MUOS) is a [[United States Space Force]] [[narrowband]] [[military satellite|military]] [[communications satellite]] system that supports a worldwide, multi-service population of users in the [[ultra 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, higher [[bit rate]]s and improved operational availability. The MUOS was declared fully operational for use in 2019.<ref>{{cite web|url=https://www.naval-technology.com/news/us-navy-declares-muos-satcom-system-ready-for-full-operational-use/|title=U.S. Navy declares MUOS satcom system ready for full operational use|publisher=Naval Technology|date=17 October 2019 |access-date=18 May 2021}}</ref>

== Overview ==
[[Image:MUOS construction.jpg|thumb|upright=1.0|right|Installing a MUOS satellite dish in [[Hawaii]]]]

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-era [[Ultra High Frequency Follow-On]] (UFO) satellite communication system. MUOS primarily serves the [[United States Department of Defense]] (DoD); although, international allies' use has been declined in the past.<ref>{{cite web|url=http://spacenews.com/38051news-from-global-milsatcom-us-allies-access-to-muos-debated-after-north/ |title=U.S. Allies' Access to MUOS Debated after North Pole Satcom Demo|publisher=SpaceNews|date=8 November 2013|access-date=18 May 2021}}</ref> 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]].<ref name="MUOS GOV">{{cite web|url=http://www.research.telcordia.com/society/TacCom/papers99/36_7.pdf|archive-url=https://web.archive.org/web/20090227003828/http://www.research.telcordia.com/society/TacCom/papers99/36_7.pdf|url-status=dead|archive-date=2009-02-27|title=Military Communications Satellite System, Multiplies UHF Channel Capacity for Mobile Users|publisher=Telcordia|date=27 February 2009|access-date=18 May 2021}} {{PD-notice}}</ref>

The [[United States Navy|U.S. Navy]]'s Communications Satellite Program Office (PMW 146) of the Program Executive Office (PEO) for Space Systems in [[San Diego]], is lead developer for the MUOS program.<ref name="PMW146">{{cite web|url=https://www.globalsecurity.org/space/library/report/1999/uhf_follow-on_fact_sheet.pdf|title=Fact Sheet, Navy Communications Satellite Programs, Ultra High Frequency Follow-On (UFO) Program |publisher=US Navy|date=1 March 1999|access-date=18 May 2021}} {{PD-notice}}</ref> [[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.<ref name="MUOS Contract">{{cite web|url=https://enterprise.spawar.navy.mil/UploadedFiles/CA-2004-037.pdf|archive-url=https://web.archive.org/web/20041022055822/https://enterprise.spawar.navy.mil/UploadedFiles/CA-2004-037.pdf|url-status=dead|archive-date=2004-10-22|title=Space and Naval Warfare Systems Command Awards Contract|publisher=SPAWAR|date=24 September 2004|access-date=18 May 2021}} {{PD-notice}}</ref><ref name="Sept2008Awards">[http://www.defenselink.mil/contracts/contract.aspx?contractid=2854 DoD Contract Awards for September 24, 2004]</ref> Key subcontractors include [[General Dynamics Mission Systems]] (Ground Transport architecture), [[Boeing]] ([[Legacy system|Legacy]] UFO and portions of the WCDMA [[Payload (air and space craft)|payload]]) and [[Harris Corporation|Harris]] (deployable mesh reflectors). The program delivered five satellites, four ground stations, and a terrestrial transport network at a cost of US$7.34 billion.<ref name="GAO-13-294SP">{{cite web|url=https://www.gao.gov/assets/gao-13-294sp.pdf|title=Report to Congressional Committees, Defense Acquisitions, Assessments of Selected Weapon Programs|publisher=U.S. Government Accountability Office|pages=99–100|date=March 2013|access-date=18 May 2021}} {{PD-notice}}</ref>

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 MUOS [[UMTS#W-CDMA (UTRA-FDD)|Wideband Code Division Multiple Access (WCDMA)]] capability, according to [[Naval Information Warfare Systems Command|Naval Information Warfare Systems Command (NAVWAR)]].

=== WCDMA system ===
MUOS WCDMA radios can transmit simultaneous voice, video and mission data on an [[Internet 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 the [[Soldier|warfighter]] with modern [[Mobile phone|cell phone]]-like capabilities, such as [[multimedia]]. It converts a commercial third generation (3G) [[UMTS|Wideband Code Division Multiple Access]] (WCDMA) cellular phone system to a military UHF SATCOM radio system using [[geosynchronous satellites]] in place of [[Cell site|cell towers]]. By operating in the [[Ultra high frequency]] (UHF) frequency band, a lower frequency band than that used by conventional terrestrial [[cellular network]]s, the MUOS provides warfighters with the [[Tactic (method)|tactical]] ability to communicate in "disadvantaged" environments, such as heavily forested regions where higher frequency signals would be unacceptably [[attenuation|attenuated]] 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.

=== Legacy payload ===
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.

== Launches ==
MUOS-1, after several weather delays, was launched into space successfully on 24 February 2012, at 22:15:00 UTC, carried by an [[Atlas V]] [[launch vehicle]] flying in its 551 configuration.<ref name="NSF20120224">{{cite web|url=https://www.nasaspaceflight.com/2012/02/atlas-v-launch-muos-historic-centaur-milestone/|title=Atlas V finally launches with MUOS – Centaur celebrates milestone |publisher=NASASpaceFlight.com|date=24 February 2012|access-date=18 May 2021}}</ref>

MUOS-2 was launched on schedule on 19 July 2013, at 13:00:00 [[Coordinated Universal Time|UTC]] aboard an Atlas V 551 (AV-040).<ref name="NSF20130719">{{cite web|url=https://www.nasaspaceflight.com/2013/07/ula-atlas-v-launch-muos-2/|title=ULA Atlas V launches with MUOS-2 satellite|publisher=NASASpaceFlight.com|date=19 July 2013|access-date=18 May 2021}}</ref>

MUOS-3 was launched on board a United Launch Alliance (ULA) Atlas V launch vehicle on 20 January 2015, from [[Cape Canaveral Space Force Station|Cape Canaveral Air Force Station]] (CCAFS), [[Florida]].<ref name="NT20150104">{{cite web|url=https://www.naval-technology.com/news/newsus-navy-prepares-for-third-muos-satellite-launch-4481335|title=US Navy prepares for third MUOS satellite launch|publisher=Naval Technology|date=4 January 2015|access-date=18 May 2021}}</ref><ref name="NSF20150120">{{cite web|url=https://www.nasaspaceflight.com/2015/01/ula-atlas-v-third-muos-spacecraft/|title=ULA Atlas V successfully launches third MUOS spacecraft|publisher=NASASpaceFlight.com|date=20 January 2015|access-date=18 May 2021}}</ref>

MUOS-4 arrived at Cape Canaveral on 31 July 2015.<ref name="SN20150701">{{cite news|url=https://spacenews.com/u-s-navys-muos-4-shipped-for-august-launch/|title=U.S. Navy's MUOS-4 Shipped for August Launch |publisher=SpaceNews|date=1 July 2015|access-date=18 May 2021}}</ref> Weather conditions pushed back the launch, which was originally scheduled for on 31 August 2015, at 10:07 UTC.<ref name="SFN20150828">{{cite web|url=https://spaceflightnow.com/2015/08/28/tropical-weather-threatens-mondays-scheduled-atlas-5-launch/|title=Tropical weather threatens Monday's scheduled Atlas 5 launch|publisher=Spaceflight Now|date=28 August 2015|access-date=18 May 2021}}</ref><ref name="Cision">{{cite web|url=https://www.prnewswire.com/news-releases/counting-down-us-navy-lockheed-martin-ready-to-launch-muos-4-secure-communications-satellite-august-31-300134742.html|title=Counting Down: U.S. Navy, Lockheed Martin Ready to Launch MUOS-4 Secure Communications Satellite August 31|publisher=Lockheed Martin|date=28 August 2015|access-date=18 May 2021}}</ref> The launch took place on 2 September 2015, at 10:18:00 UTC.<ref name="SFN20150902">{{cite news|url=https://spaceflightnow.com/2015/09/01/av-056-journal/|title=Live coverage: Atlas 5 countdown and launch journal|publisher=Spaceflight Now|date=2 September 2015|access-date=18 May 2021}}</ref>

MUOS-5 arrived at Cape Canaveral on 9 March 2016.<ref name="SFN20160309">{{cite web|url=https://spaceflightnow.com/2016/03/09/muos-5-satellite-comes-to-florida-on-way-to-geosynchronous-orbit/|title=MUOS 5 satellite comes to Florida on way to geosynchronous orbit|publisher=Spaceflight Now|date=9 March 2016|access-date=18 May 2021}}</ref> Launch was originally scheduled for on 5 May 2016, but due to an internal investigation into an [[Cygnus CRS OA-6#Launch|Atlas V fuel system problem]] during the [[Cygnus OA-6]] launch on 22 March 2016, the scheduled date was pushed back.<ref name="SFN20160412">{{cite web |url=https://spaceflightnow.com/2016/04/12/new-target-date-for-next-atlas-5-launch/|title=New target date for next Atlas 5 launch|publisher=Spaceflight Now|date=12 April 2016|access-date=18 May 2021}}</ref> The launch took place on 24 June 2016, at 14:30:00 UTC.<ref>{{cite news|url=http://spacenews.com/atlas-5-returns-to-flight-with-launch-of-navys-muos-5/|title=Atlas V returns to flight with launch of Navy's MUOS-5|publisher=SpaceNews|first=Mike|last=Gruss |date=June 24, 2016|access-date=August 14, 2016}}</ref> An "anomaly" aboard the satellite occurred a few days later, however, when it was still in a [[Geostationary Transfer Orbit]] (GTO), leaving it "Reconfigured into Safe Intermediate Orbit", or stranded in GTO.<ref>{{cite news|url=http://www.navy.mil/submit/display.asp?story_id=95601|archive-url=https://web.archive.org/web/20160709143356/http://www.navy.mil/submit/display.asp?story_id=95601|url-status=dead|archive-date=9 July 2016|title=MUOS-5 Transfer Maneuver Temporarily Halted, Satellite Reconfigured into Safe Intermediate Orbit|publisher=United States Navy|date=July 8, 2016|access-date=July 11, 2016}} {{PD-notice}}</ref><ref>{{cite news|url=http://spaceflightnow.com/2016/07/08/navys-new-muos-5-communications-satellite-hits-snag-in-space/|title=Navy's new MUOS-5 communications satellite experiences snag in space|publisher=Spaceflight Now|first=Justin|last=Ray|date=July 8, 2016|access-date=August 14, 2016}}</ref> Amateur observers tracked it in an orbit of approximately {{cvt|15240|xx|35700|km}} since 3 July 2016.<ref>{{cite web|url=http://sattrackcam.blogspot.nl/2016/07/muos-5-stuck-in-gto.html|title=MUOS-5 stuck in GTO|publisher=SatTrackCam Leiden (b)log|first=Marco|last=Langbroek|date=July 8, 2016|access-date=July 11, 2016}}</ref> On 3 November 2016, the Navy announced that the satellite has finally reached operational orbit.

== MUOS operational positions ==
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).<ref>{{cite web |url=http://www.jhuapl.edu/techdigest/TD/td3002/Oetting.pdf|title=J.D. Oetting and Tao Jen: The Mobile User Objective System. ''Johns Hopkins APL Technical Digest'' 30:2 (2011)|access-date=July 11, 2016 |archive-url=https://web.archive.org/web/20141216001751/http://www.jhuapl.edu/techdigest/TD/td3002/Oetting.pdf|archive-date=December 16, 2014|url-status=dead}}</ref> 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.<ref>{{cite web |url=http://sattrackcam.blogspot.nl/2015/09/muos-4-at-its-172-w-check-out-location.html|title=MUOS-4 at its 172 W check-out location|website=sattrackcam.blogspot.com|date=25 September 2015 |access-date=July 11, 2016}}</ref>

== MUOS ground stations ==
[[Image:The Mobile User Objective System.jpg|thumb|upright=1.0|right|MUOS ground station in [[Wahiawa, Hawaii]]]]

The MUOS includes four ground station facilities.<ref name="MUOS GOV"/> Site selections were completed in 2007 with the signing of a [[Memorandum of understanding|Memorandum of Agreement]] (MOA) between the U.S. Navy and the [[Department of Defence (Australia)|Australian 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: the [[Australian Defence Satellite Communications Station]] at [[Kojarena, Western Australia]] about 30 km east of [[Geraldton, Western Australia]]; [[Naval Radio Transmitter Facility (NRTF) Niscemi]] about 60 km from [[Naval Air Station Sigonella]], [[Sicily]], [[Italy]]; Naval SATCOM Facility, Northwest Chesapeake, Southeast Virginia at {{coord|36.564393|-76.270477|region:US_type:landmark |display=inline}}; and the [[Naval Computer and Telecommunications Area Master Station Pacific]], [[Hawaii]].

=== Controversy ===
Construction of the ground station in [[Italy]] 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 of [[Niscemi]]".<ref>[http://staff.polito.it/massimo.zucchetti/RelazionRischiAssociatiRealizzazioneMUOS1.pdf Risk Analysis Turin University]</ref> In spite of the controversy, the site at Niscemi was completed in anticipation of the launch of MUOS-4.

== Radio terminals ==
The MUOS waveform with complete [[Red/black concept|red/black]] operational capability was released in 2012. Until the [[Joint Tactical Radio System]] (JTRS) program cancellation in 2011, the JTRS program would provide the DoD terminals that can communicate with the MUOS WCDMA [[waveform]] with a series of form-factor models. The JTRS Handheld, Manpack and Small Form Fit (HMS) [[Joint Tactical Radio System|AN/PRC-155]] manpack built by [[General Dynamics Mission Systems]] survived the wider JTRS program cancellation and has shipped several low rate of initial production (LRIP) units. [[Rockwell Collins]] [[AN/ARC-210]]<ref>[http://www.rockwellcollins.com/sitecore/content/Data/News/2013_Cal_Yr/GS/FY14GSNR10-MUOS.aspx ARC-210 successfully completes first inflight MUOS tests on 19 November 2013]</ref><ref>[http://www.rockwellcollins.com/sitecore/content/Data/News/2014_Cal_Year/GS/FY14GSNR57-MUOS.aspx Rockwell Collins ARC-210 becomes first airborne radio to operate on MUOS satellite system Oct. 1, 2014]</ref> airborne terminal and [[Harris Corporation]] [[AN/PRC-117|AN/PRC-117G]].<ref>[http://harris.com/view_pressrelease.asp?pr_id=3658 Harris Corporation Falcon III Manpack Radio Successfully Communicates with MUOS Satellite Constellation December 2, 2013]</ref><ref>[http://harris.com/view_pressrelease.asp?act=lookup&pr_id=3693 Harris Corporation Continues Successful Demonstrations of Falcon III Manpack Radio with Mobile User Objective System April 24, 2014]</ref> Manpack have also been certified for operation on the MUOS system.

== Arctic and Antarctic capabilities ==
Lockheed Martin and an industry team of radio vendors demonstrated extensive Arctic communications reach near the [[North Pole]], believed to be the most northerly successful call to a geosynchronous satellite.<ref>[http://www.lockheedmartin.com/us/news/press-releases/2014/january/131-ss-muos.html Lockheed Martin MUOS Satellite Tests Show Extensive Reach in Polar Communications Capability]</ref> 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 the [[Northwest Passage]] and [[Northeast Passage]] shipping lanes is expected. Several follow-on tests with high quality voice and data including streaming video have occurred in both the [[Arctic]] and [[Antarctic]], including a 2015 demonstration from [[McMurdo Station]].<ref>[https://defensesystems.com/articles/2015/08/24/afrl-navy-lockheed-muos-antarctica-tests.aspx Researchers take high-bandwidth communications to the South Pole]</ref>

== See also ==
{{Portal|Spaceflight}}
* [[Global Information Grid]]
* [[Network-centric warfare]]

== References ==
{{Reflist}}

== External links ==
* [http://space.skyrocket.de/doc_sdat/muos-1.htm] MUOS 1, 2, 3, 4, 5
* {{cite journal|url=http://www.jhuapl.edu/techdigest/TD/td3002/Oetting.pdf|title=The Mobile User Objective System|journal=Johns Hopkins APL Technical Digest|first1=John D.|last1=Oetting|first2=Tao|last2=Jen |volume=30|issue=2|date=2011|access-date=December 15, 2014|archive-url=https://web.archive.org/web/20141216001751/http://www.jhuapl.edu/techdigest/TD/td3002/Oetting.pdf|archive-date=December 16, 2014|url-status=dead}}

{{Lockheed Martin}}
{{Orbital launches in 2015}}
{{Orbital launches in 2016}}

[[Category:Equipment of the United States Space Force]]
[[Category:Military communications of the United States|G]]
[[Category:Military space program of the United States]]
[[Category:Lockheed Martin]]
[[Category:General Dynamics Mission Systems]]
[[Category:Satellites using the A2100 bus|MUOS]]

Mobile User Objective System - Revision history

2601:985:D01:36F6:0:0:0:DE: /* Overview */