SAN DIEGO (NNS) -- The Mobile User Objective System (MUOS), directed by Team Space and Naval Warfare Systems Command's (SPAWAR's) Communications Satellite Program Office (PMW 146), completed a significant test milestone for the program's first satellite June 29.
A next-generation narrowband tactical satellite communications system, MUOS will provide the warfighter with the latest mobile technology such as simultaneous voice and data, as well as improved service to legacy users of the current ultra high frequency (UHF) Follow-On system.
"Since the MUOS spacecraft's Critical Design Review in March 2007, we have overseen the manufacture and delivery of hundreds of components that make up the MUOS spacecraft," said Navy Capt. Jack Nicholson, PMW 146's acting program manager.
The successful testing demonstrates that components work together as an integrated spacecraft and will meet the warfighter's needs for UHF communications. "It is a major accomplishment to have first pass success at the system level testing for such a complex spacecraft," said Nicholson.
The next steps are spacecraft level vibration and acoustic tests to simulate the launch environment, followed by thermal vacuum tests that simulate the extreme hot and cold temperature on orbit. Upon completion of these tests there will be final post-environmental performance tests to verify that the satellite works properly prior to launch.
"We are about one year from being ready to launch the first MUOS spacecraft, and we are ready for the next major test event: spacecraft vibration and acoustic testing," explained Nicholson. The first MUOS satellite is projected to provide on-orbit capability by the end of 2011.
The first MUOS satellite successfully completed Passive Intermodulation (PIM) testing, Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) testing, as well as the Spacecraft Level Baseline Integrated System Test (BIST) at Lockheed Martin facilities in Sunnyvale, Calif.
Completion of PIM testing assured that the high power satellite downlink transmissions do not interfere with the extremely low power signals uplinked from the legacy terminals used by the warfighter. The EMI/EMC testing ensures self-compatibility of the payloads on the satellite, as well as satellite compatibility with the launch vehicle electromagnetic environment. BIST testing verifies the overall performance of the fully integrated MUOS spacecraft is compliant to the MUOS Performance Specification and establishes a performance baseline prior to entering the environmental test phase.
"Completion of PIM, EMI and EMC on the first pass and in less than two months on a UHF satellite as complex as MUOS is the result of months of planning and hard work by the entire MUOS space segment team," said Nicholson. "This team was efficient at identifying and completing risk reduction activities that led to this major testing milestone."
Following BIST, a series of critical environmental test phases that validate the overall satellite design, quality of workmanship and survivability during space vehicle launch and on-orbit operations will take place.
MUOS is the Defense Department's next-generation military satellite communication system that supports a worldwide, multi-service population of users in the narrowband. The system is designed to support users that require greater mobility, higher data rates and improved operational availability. This system will provide greater than 10 times the system capacity of the current narrowband constellation.
MUOS will support unified commands and joint task force components, DoD and non-DoD agencies, and U.S. allies by providing worldwide tactical narrowband netted, point-to-point, and broadcast voice and data services in such challenging environments as double canopy foliage, urban environments, high sea states and all weather conditions.
The Mobile User Objective System is an array of geosynchronous satellites being developed for the United States Department of Defense (DoD) to provide global satellite communications (SATCOM) narrowband (64 kbit/s and below) connectivity for communications use by the United States and allies.
The Mobile User Objective System (MUOS) is an Ultra High Frequency (UHF) SATCOM system, primarily serving the DoD. As mentioned above, the MUOS will replace the legacy UHF Follow-On (UFO) system before that system reaches its end of life to provide users with new capabilities and enhanced mobility, access, capacity, and quality of service. Intended primarily for mobile users (e.g. aerial and maritime platforms, ground vehicles, and dismounted soldiers), MUOS will extend users' voice, data, and video communications beyond their lines-of-sight.
The MUOS operates as a global cellular service provider to support the war fighter with modern cell phone-like capabilities, such as multimedia. It converts a commercial third generation (3G) Wideband Code Division Multiple Access (WCDMA) cellular phone system to a military UHF SATCOM radio system using geosynchronous satellites in place of cell towers. By operating in the UHF frequency band, a lower frequency band than that used by conventional terrestrial cellular networks, the MUOS provides warfighters with the tactical ability to communicate in "disadvantaged" environments, such as heavily forested regions where higher frequency signals would be unacceptably attenuated by the forest canopy. The MUOS constellation will consist of four operational satellites and one on-orbit spare. MUOS will provide military point-to-point and netted communication users with precedence-based and pre-emptive access to voice, data, video, or a mixture of voice and data services that span the globe. 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 a related story by Space News Staff Writer Turner Brinton, integration woes have delay the launch of Navy's 1st MUOS satellite into 2011.
The Navy is now developing a strategy to mitigate a potential gap in narrowband ultra-high frequency (UHF) satellite capacity in the next few years, Navy Vice Adm. Harry B. Harris, deputy chief of naval operations for communications networks, said during a 2009 hearing of the Senate Armed Services strategic forces subcommittee. One option the Navy looked at, which entailed having a commercial satellite host a dedicated UHF payload for Navy use, would not have been ready in time to solve the problem, he said.
Today, the Navy gets its UHF satellite capacity via its fleet of eight operational UHF Follow- On satellites built by Boeing Space and Intelligence Systems of Seal Beach, Calif.; two previous-generation Fleet Satellite Communications System craft; the Leasat 5 satellite leased from Intelsat General Corp. of Bethesda, Md.; and leased capacity on the Skynet 5C satellite owned by Paradigm Secure Communications of the United Kingdom. The UHF Follow-On constellation was predicted to degrade to an unacceptable performance level by May 2010, and the Leasat 5 satellite is expected to reach the end of its service life in early 2011, Harris said.
Lockheed Martin Space Systems of Sunnyvale Calif., is building four next-generation MUOS satellites that were previously expected to begin launching in March 2010. That launch date has now slipped to no earlier than February 2011, Harris said. Based on the current launch manifest, we believe here on the Milcom blog that the February 2011 will slip later into 2011.
The MUOS satellites, designed to provide links to ships at sea as well as to highly mobile ground forces operating in hard-to-reach places such as beneath jungle canopies, have two payloads: a legacy payload built by Boeing that is identical to those on the UHF Follow-On satellites, and a more advanced Lockheed Martin-built UHF payload that will provide more capacity. Lockheed Martin is experiencing difficulties mating the Boeing-built payload with its A2100 satellite bus, Harris said.
The Navy is taking steps to minimize the impact of any possible UHF gap in the future. The service has extended its leases on commercial satellites, and the UHF Follow- On program office took advantage of the satellites' component redundancy to allow the use of 10 additional channels, which have been in use since December 2008, Harris said.
The Navy in March 2008 solicited information from industry about the possibility of hosting a UHF payload aboard a commercial satellite. When asked about this option, Harris said a commercial solution could not be operational until around 2012, presumably after the first MUOS satellite has been launched.
The Navy canceled its plans to enter into a hosted UHF payload arrangement earlier this year.
