The first of a new constellation of US Navy communications satellites entered orbit today after a successful launch by a Lockheed Martin Atlas V heavylift rocket.
The mobile user objective system (MUOS) satellite separated from the rocket's third-stage booster -- a Pratt & Whitney Rocketdyne RL10 Centaur -- about 3h after lift-off at 17:15 from Cape Canaveral, Florida.
Poor weather had cancelled two previous launch attempts a week earlier.
Lift-off on the third attempt came at the beginning of a 45min launch window.
The USN will launch five more satellites to complete the MUOS constellation, the largest payload ever carried to orbit by the 65-year-old Atlas rocket series.
The MUOS constellation is designed to expand access to the UHF spectrum for mobile users ranging from dispersed special forces teams to the Lockheed F-35 Lightning II.
The United Launch Alliance, a Lockheed-Boeing joint venture, plans to launch six more Atlas V and four four Boeing Delta IV rockets this year.