WASHINGTON — The fourth satellite in the U.S. Navy’s next-generation mobile communications system has completed testing and is in its final checkout after an accelerated production cycle, according to a July 10 press release from the program’s prime contractor, Lockheed Martin Space Systems.

The Mobile User Objective System-3 satellite is expected to launch in January 2015.

Lockheed Martin put a rush on the fourth satellite after a soldering problem delayed production of the third in the series. The Navy also modified the launch order of the satellites.

“We are committed to quality, and our rigorous environmental testing regimen ensures this system is ready for the harsh environments of space,” Iris Bombelyn, Lockheed Martin vice president of narrowband communications, said in the release. “It’s important to check out every aspect of the satellite at this stage so we can prepare it for service.

The MUOS constellation is designed to provide smartphone-like communications to mobile U.S. forces as well legacy mobile services at rates 10 times faster than system it is replacing.

Lockheed Martin Space Systems of Sunnyvale, California, is under contract to build five MUOS satellites, the first and second of which were launched in February 2012 and July 2013, respectively. The MUOS-5 satellite, which Lockheed Martin refers to as production vehicle No. 3, is slated to launch in 2016.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.