Navy launches fourth and final MUOS satellite

The launch of MUOS-4, the final hub of a new global constellation for the military, will allow military personnel to instantaneously communicate across all corners of the globe.

There’s a new constellation in the sky, and it will allow U.S. military personnel to communicate with each other from virtually anywhere on Earth.

MUOS-4, the final satellite in the Mobile User Objective System array, was launched early Wednesday after a two-day delay from tropical storm conditions. Three hours after its ascent, operators on the ground received its signal, meaning that it has survived its journey and will continue up to geosynchronous orbit 22,000 miles above the Earth’s surface.

Unlike previous satellite arrays, which relied on users being within a certain radius of their orbit to access the network, the MUOS system will enable military forces to tap into a narrowband spectrum to talk, text or exchange information on a global playing field. According to the Navy, which launched MUOS-4, these new capabilities will prove invaluable to mobile forces, like submarines, ships and aircraft, that are rarely in the same place for extended periods of time.

“With MUOS, the population of disadvantaged users is going to shrink considerably,” said Cmdr. Pete Sheehy, MUOS principal assistant program manager, in a release. “And that new population of folks who have beyond-line-of-sight communication are going to be able to do their jobs more efficiently and safely. It could be as simple as that one person who otherwise might not have had beyond-line-of-sight comms being able to say ‘This is where I am. This is who I am and I need help.’ And know that someone is on the other side to be able to provide that support.”


To ease the transition from legacy communications processes to the MUOS network, each satellite in the array has been equipped with both systems. MUOS-1 and MUOS-2, launched in 2012 and 2013 respectively, are already providing legacy communications services from their own orbits. MUOS-3, launched in January, is undergoing final testing phases before being declared mission-ready. A fifth satellite is expected to be launched in 2016 and will act as a replacement should any of the others become inoperable.

The MUOS system is rooted in Internet Protocol, allowing for a nuanced network containing classified and unclassified information. Practically, the network will function on macro and micro levels: from coordinating between large transports to allowing for the distribution of situational awareness data within tactical units. This is owed to a design that, according to MUOS technical Director Jim Parsons, is founded on flexibility.

“The nice thing about MUOS is that the ground system and terminals contain all the switching and routing technology,” Parsons said. “The satellite remains unchanged over time and can allow technology insertion into the ground stations and the waveform over time to increase capability without having to make any satellite changes.”

According to Jarratt Mowery, director of MUOS end-to-end system testing, this flexibility also extends to environmental considerations.

“In our testing we’ve tried to be as realistic as possible. In several events we’ve brought uniformed warfighters in and given them training on the MUOS system and operating its components,” Mowery said in the release. “They were able to define the types of operations they would like to use the system [for] and [it] allowed them to exercise those operations in a realistic environment. Be that in vehicles driving around, in a forest with a thick canopy or even in airborne platforms.”


The new array will also offer a perk to those who have long been frustrated by a lack of reception at the ends of the Earth, vastly expanding satellite coverage toward the North and South poles.

“With the launch of MUOS-4 we’re going to deliver that worldwide coverage and communication service for users,” said Nina Tran, MUOS space division director, in the release. “We are benefitting from providing the legacy channels for current users and we are exploring all the capability that MUOS has to offer.”

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