Photos: Atlas 5 rocket on the pad with WorldView 4 satellite

With an international flair for collaboration, a military communications satellite jointly purchased by five allies was rocketed in space Saturday to further expand the U.S.-operated network that serves battlefield forces anywhere on Earth.

SpaceX’s Falcon 9 rocket will launch a third-generation GPS navigation satellite for the U.S. military in 2018, the Air Force said Wednesday, breaking a monopoly held by United Launch Alliance since its formation nearly a decade ago.

Citing schedule concerns over price benefits, Iridium announced Thursday it will launch its next 20 satellites on a pair of previously-flown Falcon 9 boosters from Vandenberg Air Force Base in California, beginning with a Dec. 22 mission.