MUOS: Milsatcom’s Cutting Edge

By Ron Sherman | June 1, 2005
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Imagine a U.S. Air Force or Navy pilot flying his newly minted F-35 in combat. He needs to communicate immediately on several levels to accomplish his mission: talk to the tactical center, talk to his wingman, and send vital data and video to mission controllers in the air and on the ground. Imagine, too, an Army or Marine squad leader, isolated by distance and a tropical environment, communicating instantly via a secure cell phone device into his tactical or even strategic operations network for assistance in carrying out a mission. In today's world, these scenarios are not possible. But, by early next decade, a cutting-edge U.S. Navy satellite program called Multiple User Objective System (MUOS) could enable all of the above instantaneously.

The Navy describes MUOS as a protected (i.e., encrypted), narrowband (64-Kbit/s and below) satellite communications system that will support a worldwide, multiservice population of mobile and fixed-site terminal users. True enough, but a modest definition at best. MUOS has been described as a quantum leap in mobile, portable military satcom designed for use on the ground, in the air and on the sea. The Navy is developing and will operate MUOS for the Department of Defense (DoD).

Capt. David Porter, program manager for the Navy Satellite Communications Program Office, emphasizes the importance of the new satcom system's improved capacity, terminal mobility and ease of use. He explains that in today's challenging military environment, warfighters must be able to communicate rapidly in the dynamic battlefield. MUOS would give them reliable communications links immediately, regardless of weather, jungle foliage or urban canyons. With the adaptation of third-generation (3G) mobile cellular technology, MUOS is expected to deliver secure simultaneous voice, data and video connections with cell phone simplicity, "something heretofore not possible," says Porter.

Better Than UFO

This would involve a 10-fold increase in transmission throughput (volume of information), compared with the Navy's current UHF Follow-on (UFO) satellite system. The MUOS constellation is expected to boost satellite capacity and data rates substantially. The MUOS system would provide the capacity of 39 Mbits/s, compared with the predecessor UFO capacity of 2.5 Mbits/s. To put it another way, a MUOS satellite would provide more than 7,000 simultaneous accesses (video, voice and data) at 2.4 Kbits/s, compared with 106 accesses for a UFO satellite at 2.4 Kbits/s. As the total simultaneous accesses are reduced, the channel rate goes up. MUOS satellites will be fully compatible with the UFO system and associated legacy terminals.

MUOS enables true "coms-on-the-move," according to Porter, adding that, should an unexpected event occur, warfighters would be able to easily report to or summon assistance from their chain of command without having to aim an antenna and expose themselves to hostile fire.

Joint Tactical Radio System (JTRS) radios are expected to incorporate the MUOS waveform. The goal is to achieve handheld cell phone-like services via MUOS satellites that act like very tall cell towers. Porter says that, "strategically, MUOS will facilitate rapid response to any part of the globe." Ground troops, sailors and airmen would have "instantaneous access to prearranged tactical networks and worldwide communications, including the global information grid [GIG]," he adds.

According to Porter, "with JTRS terminals equipped with omnidirectional antennas, convoys of Humvees and tanks, soldiers fighting in urban areas, Air Force command and control aircraft supporting special ops, or Marines fighting in harsh climates will all be in constant communication within their chain of command."

Sounds good, but today's warfighters will have to wait a few years. The MUOS constellation of four geosynchronous satellites (and one spare) will not reach full operational capability until some time after 2014. In fact, the first satellite will not be launched from Cape Canaveral for at least four more years. The MUOS constellation is required to provide satellite communications for 10 years beyond full operational capability. Further, much work must be accomplished to modify the JTRS ground infrastructure to be compatible with MUOS.

Where It All Started

Building on the foundation of UHF communications, the Navy volunteered in 1996 to lead a joint mobile user study to identify the future of narrowband users. The goal was to recommend an affordable narrowband transition plan from the current UFO constellation.

An analysis of mobile user requirements determined that nearly 25 percent of tactical, point-to-point communications can be offloaded to commercial systems. The remainder would need to be satisfied through a narrowband objective system. UHF would be necessary in order for small handheld terminals to penetrate jungle foliage, weather and urban structures. The Navy also concluded that MUOS could use in-orbit processing for message routing and signal gain for disadvantaged (legacy) terminals. Use of the existing UHF satellite ground terminal infrastructure--a mix of legacy terminals compatible with early milsatcom programs--also is desired.

The technical challenges associated with MUOS include integrating the satellite ground infrastructure, terminals and commercial segments, as well as related contractual, economic and spectrum allocation issues. The concept came together in autumn 2004, when DoD awarded a Lockheed Martin-led team a $2.1-billion contract to achieve initial operating capability by 2010. Added options could increase the contract value to more than $3 billion through 2014.

In managing the MUOS development program, the Lockheed team has "set up a virtual, protected network with a daily shared design review interface that includes all subcontractors, as well as the customer [Navy] team," says Len Kwiatkowski, Lockheed's vice president and general manager for military space programs. An executive management team meets quarterly for development oversight.

Kwiatkowski says MUOS represents a quantum leap in capability but not in technology, which is already quite available. "There is wide use of commercial off-the-shelf [COTS] technology, customized for military use," he explains. "We're using a good deal of hardware that was developed for commercial space systems."

Kwiatkowski also underlines the importance of the receiver's portability. "These handheld receivers will be roughly the same size as today's Iridium satellite handheld phones but a huge leap forward from cell phones--very secure with a much faster rate of download capability, up to 384 Kbits/s." The handheld device will have a unique flip-up MUOS antenna attached to its back. Airborne and sea-based assets will use the same mobile technology to communicate through the MUOS satellite system but with embedded terminals specifically designed for the mission.

Over time MUOS technology could find its way into commercial systems and solutions, but Kwiatkowski would not elaborate for competitive reasons. He also points out that eventually these resources could be shared with NATO nations and other U.S. allies--but not right away.

Asian Import

Lockheed's MUOS satellite design is comparable to what the company uses in the commercial Asian Cellular Satellite (ACeS) program. "This is purposeful in order to lower the risk," says Kwiatkowski. ACeS operates in the S-band with a C-band feeder link.

As most teenagers know, 3G cellular phone networks provide streaming video, as well as network, data and voice communications. These features, transformed for military use, will be at the heart of MUOS.

According to General Dynamics, the ground infrastructure will include numerous sites that will talk to the MUOS satellites, collect the signals, and tie them into various DoD networks. Among the ground elements are:

  • The radio access facility--sometimes referred to as the "tall tower" cellular antenna;

  • The switching and network management facilities; and

  • A control facility with a satellite uplink that provides an overall Navy management function.

Orbital operations--including launch and early operations, payload status and anomaly resolution--will be handled by the Naval Network and Space Operations Command and the Naval Satellite Operations Center, both at Point Magu, Calif., and the latter's Detachment Delta at Schriever AFB, Colo. Satellite use operations--including provisioning, administration and help desk (the military equivalent to a customer service center)--will be the responsibility of the MUOS Global Satellite Support Center, co-located at the U.S. Strategic Command, and several regional support centers sited at various combatant commands. Navy facilities in Hawaii and Virginia will manage the network.

General Dynamics and InterDigital are cooperating to provide the JTRS waveform that will drive MUOS capability. The two companies are developing the core set of software to be installed in JTRS terminals, allowing MUOS to talk to the JTRS network.

General Dynamics also is employing COTS to develop MUOS mobile technology. The company is using commercial Universal Mobile Telecommunication System cellular technology with wideband code division multiple access (WCDMA), combined with Ericsson 3G technology.

Harris' satellite antennas, some more than 47 feet (14 m) in diameter, will enable the use of several spot beams to improve signal-to-noise levels and achieve up to 30-fold frequency reuse, something which is not possible in the UFO program. Comparable commercial systems now use L-band, 1.5-GHz downlinks.

JTRS-designed handheld terminals are intended to provide cell phone-like services to soldiers on the ground. Like cell phone services, the system would always be on. Using adaptive power control, MUOS would assign bandwidth only when the user requires it and only use bandwidth when a call is being made. The JTRS program is developing mobile, always on receivers for use in aircraft, ships and submarines, as well as in command and control centers around the world. As the demand for the communications service grows and budgets allow, the MUOS constellation probably would grow, as well.

Program Status

Although the Navy and Lockheed both claim there has been no program delay, the original MUOS concept has changed. Plans had called for launching the first of a proposed six to eight satellites, beginning in 2007, and completing the constellation in 2010. This may reflect a realization that the need to replace UFO is less urgent than had been projected, or MUOS funds may have been diverted to support the war in Iraq.

Claiming the MUOS program is fully funded in the president's 2006 budget, Porter lists the program's milestones. It received milestone-A approval in September 2002 to enter component advanced development and key decision point-B (KDP-B) approval to enter preliminary design in September 2004. Build approval and KDP-C are scheduled for October 2006 and October 2007, respectively. The follow-on buy decision is slated for October 2008.

The first MUOS launch is scheduled in late 2009, providing an on-orbit capability in March 2010. Subsequent launches are planned for October 2010, June 2011, June 2012 and June 2013, and full operational capability is expected no later than July 2014. The MUOS operational documents specify a system life span through 2024. MUOS satellites are to have a 10-year service life.

The current UFO constellation has nine satellites plus one on-orbit spare that provides a mix of 38 communications channels and one fleet broadcast channel.

"The UHF spectrum has evolved into the military's workhorse," says Porter. "There are more than 20,000 UHF terminals in use." However, the UFO system already is 250 percent oversubscribed. "Demand will only increase, as joint operations and network centric warfare evolve," Porter asserts.

The estimated need in 2010, in the combined theaters of war, is well above 40 Mbits/s with several thousand simultaneous accesses. By the first MUOS launch, the need for terminals of all types is expected to approach 100,000. About 50 percent will be handheld devices and the remainder will be older JTRS radios and terminals produced for legacy equipment.


A recent report indicates that complications with new cryptographic equipment destined for developmental military satellite programs affect the Advanced EHF (AEHF) and MUOS initiatives. "As both AEHF and MUOS will be utilizing similar cryptographic devices, development complications may have an impact on MUOS," says Porter. "We have been involved in early and proactive coordination to prevent delays related to this issue."

Since MUOS is utilizing Lockheed's A2100AX series commercial bus, a design with space-proven experience, many of the difficulties will largely be avoided, Porter contends. "In addition, taking advantage of other commercial technologies related to network management will help mitigate program risks."

MUOS technology is designed to hit at the very core of mission efficiency from individual, tactical and strategic viewpoints. While a great deal of detailed, aggressive product development work needs to be accomplished, the Navy expects the program will come together as planned. The alternative would leave military satellite communications deficient.


Lockheed Martin's Commercial Space Systems unit in Newton, Pa., is developing the MUOS satellites; final assembly and test will take place in Sunnyvale, Calif. Major subcontractors to Lockheed include:

  • General Dynamics C4 Systems, Scottsdale, Ariz., which will provide user entry and integrated ground segments of the MUOS; secure ground network, satellite control and network management; and a JTRS-compliant terminal (receiver).

  • Boeing Satellite Systems, El Segundo, Calif., which will provide the legacy UHF payload.

  • Ericsson, Plano, Texas, the leader in 3G mobile technology, which will provide vital segments of the MUOS ground system.

  • Harris Corp., Melbourne, Fla., which will provide the large reflectors for the MUOS. The reflectors, two per satellite, will be part of the satellite's UHF-band antenna system.

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