Thu, 11 Feb 2010 07:54:39 AM EST
Built by United Launch Alliance, the 191-foot-tall Atlas V-401 rocket that will boost SDO into space is composed of the orange booster stage topped by the Centaur upper stage. The spacecraft is mounted inside the protective payload fairing above the upper stage.
The next major countdown milestone is the start of the "tanking" process, when storage tanks in the rocket's booster stage and upper stage are filled with propellants. The booster's RD-180 main engine runs on a combination of liquid oxygen and Rocket Propellant-1 fuel, a refined kerosene usually referred to as RP-1. The Centaur's RL10 engine is powered by liquid oxygen and liquid hydrogen.