The third in a five-ship fleet for a next-generation, narrowband tactical military satellite communications system is now at Cape Canaveral Air Force Station in Florida, where crews are making final preparations for a scheduled Jan. 20, 2015, launch. The U.S. NAVY’s latest Mobile User Objective System satellite, identified as MUOS-3, arrived on a C-5 Galaxy transport aircraft via Lockheed Martin’s Sunnyvale, Calif., facility and nearby Moffett Federal Airfield on Nov. 5, 2014, courtesy of the 60th Air Mobility Wing of Travis Air Force Base.
“The delivery of MUOS-3 is an important step toward enabling our warfighters to be able to pick up the phone to seamlessly call or transfer data anywhere around the world,” said Iris Bombelyn, vice president of Narrowband Communications at Lockheed Martin. “With the launch of the third satellite in the constellation, to be followed later in 2015 by the fourth, MUOS will be in place to provide pole-to-pole and global, secure communications for the warfighter.”
MUOS operates like a “smart phone cell tower in the sky,” supporting a worldwide, multi-Service population of users in the UHF band, providing increased communications capabilities to smaller terminals while still supporting interoperability with legacy terminals. The new military SATCOM system will, for the first time, give MUOS Wideband Code Division Multiple Access technology users beyond-line-of-sight capability to transmit and receive voice and data using an Internet Protocol-based system, giving users greater mobility, higher data rates, and improved operational availability.
MUOS gives military users more communications capability over existing systems, including simultaneous voice, video, and data—similar to the capabilities experienced today with smart phones and providing users with 10 times more communications capacity.
With MUOS-3 now at its Florida launch site, crews from Lockheed are conducting final preparations for liftoff, which will occur on a United Launch Alliance (ULA) Atlas-V rocket from Launch Complex-41 (SLC-41). After completing post-shipment testing technicians will fuel the satellite, then encapsulate it inside the Atlas-V’s 5.4-meter (17.7-foot) bullet-like payload fairing. The encapsulated MUOS-3 satellite will then be integrated on top of ULA’s workhorse rocket for final integrated testing and closeout preparations for launch Jan. 20. The current launch window is 7:42 – 8:26 p.m. EDT.
Flying in its most powerful “heavyweight” 551 configuration, ULA’s Atlas-V will employ the added power of five strap-on Aerojet Rocketdyne solid-fueled boosters to deliver the NAVY’s 15,000-pound MUOS-3 satellite to geosynchronous orbit, more than 22,000 miles above Earth. ULA has launched 50 missions over 12 years on their Atlas-V fleet of rockets, all successfully, but only four of those missions required the 551 configuration; New Horizons to Pluto in 2006, JUNO to Jupiter in 2011, and MUOS-1 and MUOS-2. Once launched a single-engine Centaur upper stage will give MUOS-3 the final push it needs to enter its intended orbit.
Although a total of five MUOS satellites will make up the MUOS fleet, only four will actually be required to put the whole system into action; the fifth and final MUOS to launch in 2016 will serve as an on-orbit spare should any of the first four lose their capabilities.
Original plans called for the first MUOS to launch by 2010, but budgetary adjustments made in response to the Iraq war led to a two-year delay. MUOS-1 launched on Feb. 24, 2012, followed by MUOS-2 on July 19, 2013, and in the time since both have demonstrated new capabilities, especially in the Arctic, an area previously beyond the coverage of UHF satellites and growing in interest for transportation and natural resources exploration above 65 degrees north latitude. In the past year MUOS successfully connected users near the Arctic poles during independent testing by Lockheed Martin, and during the U.S. Navy’s 2014 Ice Exercise (ICEX) and the U.S. Coast Guard’s Arctic Shield 2014.
The MUOS satellites seek to offer global satellite communications narrowband (64 kbits/sec and lower) connectivity for use by U.S. and allied forces, with an ultra-high frequency range from 300 MHz-3 GHz. When fully functional, it will replace the legacy UHF Follow-On (UFO) satellite network—the first of which was launched back in March 1993—before the latter system reaches the end of its operational service. MUOS will provide new capabilities and enhanced mobility, access, capacity, and quality of service, with particular emphasis upon mobile users, such as aerial and maritime platforms, ground vehicles, and dismounted soldiers.
By operating in the UHF frequency band, which is lower than that used by conventional cellular networks, MUOS will provide U.S. and allied warfighters with the tactical ability to communicate in “disadvantaged” environments, including heavily forested areas where higher-frequency signals would be otherwise impaired. Even troops in buildings with no satellite access are expected to see an increase in communications capability.
The infrastructure to both fly the MUOS satellites and control access of a user’s communications is managed from the ground. Operationally, information flows to the satellites via UHF WCDMA links, and the satellites then relay the information to one of four ground sites located in Hawaii, Virginia, Italy, and Australia via a Ka-band feederlink. These facilities identify the destination of the communications and route the information to the appropriate ground site for Ka-band uplink to the satellite and UHF WCDMA downlink to the correct users. MUOS will also provide users access to select Defense Information System Network voice and data services.
– Written by Mike Killian and Ben Evans
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