Atlas V Launches Its Biggest Payload Ever

by Lindsay Chaney
posted July 22, 2013

The most powerful version of the Atlas V rocket lifted the Navy’s second Mobile User Objective System (MUOS) communications satellite to orbit Friday morning, July 19, from Cape Canaveral.

At nearly 15,000 pounds, it is the heaviest satellite launched by an Atlas V.

Flying in the 551 configuration, with a five-meter fairing, five solid rocket boosters and a single-engine Centaur upper stage, the rocket lifted off at 9 a.m. Eastern time (6 a.m. on the West Coast), 12 minutes into its 44-minute launch window. The delay from the launch window opening was a precaution due to upper atmosphere winds.

Reporting from Cape Canaveral three hours after the liftoff, Ray Johnson, vice president of Space Launch Operations, noted that MUOS-2 had “just completed … a very successful spacecraft separation. This was a very clean flight with no major issues.”

Johnson added “congratulations to the Atlas team for completing this very important and very successful launch.”

In a variation from a typical Atlas 5 trip to geosynchronous transfer orbit, where communications satellites are released, Friday’s launch utilized three firings of the second-stage Centaur’s engine, instead of the normal two firings. The three firings allowed the Atlas to carry an extra 1,000 pounds.

It was only the fourth Atlas V launch in the 551 configuration. The other three were the first MUOS launch, and NASA missions to Jupiter and Pluto.