Navy launches 4th satellite in global tactical comms system

A ULA Atlas V launches from Cape Canaveral, with MUOS-4 aboard.

The Navy will have near-global coverage from its high-bandwidth Mobile User Objective System, with the launch of the fourth satellite in the MUOS constellation.

MUOS-4 was launched Sept. 2 aboard a United Launch Alliance Atlas V rocket from Cape Canaveral—after a two-day delay because of tropical storm conditions—and the Navy acquired its signal about three hours later, the Navy said in a release. The system, which transmits signals at 16 times the rate of the Navy’s current Ultra High Frequency satellite system, will serve ground forces, surface ships, submarines and aircraft, including those belonging to all of the military services and special forces.

The constellation’s first two satellites were launched in 2012 and 2013, with the third going into orbit in January this year. MUOS-3 completed testing and was moved into its on-orbit position in June, at the time providing coverage of about three-quarters of the globe. MUOS-4 will provide essentially global coverage, including in the polar regions, where satellite and wireless communications have proved to be difficult. A fifth satellite, which will operate as a spare, is expected to be launched in 2016.

MUOS-4 being encapsulated in its launch vehicle in August.

"With the launch of MUOS-4 we're going to deliver that worldwide coverage and communication service for users," Nina Tran, the program office's space division director, said. "The legacy payload we have on MUOS satellites allows a smooth transition to a newer, better MUOS capability. We are benefitting from providing the legacy channels for current users and we are exploring all the capability that MUOS has to offer."

The satellites, made by Lockheed Martin, are based on a direct-sequence spread spectrum Wideband Code Division Multiple Access (WCDMA) waveform and provide secure, high-speed, IP-based voice, video and mission data. The system includes four ground stations around the world, and will extend beyond-line-of-sight capability. It’s expected to greatly benefit ground forces in need of air support, for example, the Navy said.

"With MUOS, the population of disadvantaged users is going to shrink considerably," said Cmdr. Pete Sheehy, principal assistant program manager. "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.