This is the fourth of eight flights by Orbital ATK under the Commercial Resupply Services contract with NASA. This will be the inaugural flight of the larger Enhanced Cygnus PCM. As of January 26, 2015 a United Launch Alliance Atlas 5 rocket will launch the fifth Orbital Sciences Cygnus cargo freighter on its fourth operational cargo delivery flight to the International Space Station from Cape Canaveral Air Force Station Space Launch Complex 41 on November 19, 2015. The mission is known as Orb-4. The Atlas 5 rocket will fly in the 401 vehicle configuration with a four-meter fairing, no solid rocket boosters and a single-engine Centaur upper stage.