Photos: 200th Atlas-Centaur launches MUOS 3

The preliminary weather forecast for Tuesday evening’s Atlas 5 rocket launch carrying a Navy communications satellite predicts a 60 percent chance of acceptable conditions, with thick clouds the main threat against flying at 7:43 p.m. EST as scheduled.

Launching for the 200th time and loaded with one of its heaviest cargoes ever, the Atlas-Centaur rocket flexed its muscle and sped away from Cape Canaveral on Tuesday night with a U.S. Navy satellite for mobile communications to the military and White House.

The payload will be mounted aboard the 200th Atlas-Centaur rocket Thursday, completing assembly of the most-powerful version of the vehicle available in the modern era.