A United Launch Alliance Atlas V rocket lifts the U.S. Navy's third Mobile User Objective System (MUOS) satellite into geostationary orbit at 8:04 p.m. on 20 January 2015 from Space Launch Complex-41 at Cape Canaveral Air Force Station. From the ULA press booklet about the mission:

MUOS-3 is the third of a five-satellite constellation to be launched and operated by PMW 146, the Navy’s Communications Satellite Program Office. MUOS is a next-generation narrowband tactical satellite communications system designed to significantly improve ground communications to U.S. forces on the move around the globe.

The MUOS-3 satellite will be the heaviest payload to ride into space atop any of ULA’s Atlas V launch vehicles. The Atlas V will generate more than two and half million pounds of thrust at liftoff in order to meet the demands of lifting the nearly 7.5-ton satellite.