United Launch Alliance acquired next success. 359th flight of the Delta IV Medium+ (4,2) finished with planned deploying of two observation satellites for U.S. Government.
Launch of the Delta IV with two GSSAP satellites under 4 m payload fairing was performed from Space Launch Complex 37 at Cape Canaveral AFS. Punctually on August 19 at 04:52 GMT engines of the first stage and two boosters were ignited at T-10". Rocket lifted off and left SLC-37 covered with clouds of smoke. At +1'07" rocket reached MaxQ point when stress by dynamic pressure is at the highest level during whole flight. Few seconds later rocket reached altitude of 15 km and speed of 2800 km/h. At T+1'48" both GEM-60 boosters were separated from the core of the rocket. Twelve seconds later, at T+2', rocket was heading at 95.2° on altitude of over 60 km with speed at 6000 km/h. At T+4' RS-68A main engine of the first stage was cut off. After few seconds first stage was separated and Delta Cryogenic Second Stage started its autonomous flight with ignition of its RL-10B-2 engine. At T+4'33" payload fairing was separated on altitude of 162 km when second stage reached speed of 18000 km/h. From that moment live broadcast was terminated due the classified characteristic of the payload. Satellites were deployed probably on altitude of 35398 km.