This is the 4th mission under NASA's Commercial Resupply Service agreement with Orbital ATK. The unmanned Cygnus cargo vessel delievered approximately 3,500 kg (7,700 lbs.) of supplies and science experiments to the International Space Station. The craft features a longer, enhanced cargo module and remained berthed to the station for 2 months.
An Atlas V with a 4 meter diameter fairing, no boosters and a single centaur upper stage engine.See Atlas Details
Cygnus CRS OA-4, also known as Orbital ATK CRS-4 and CRS Orb-4, was the fourth successful flight of the Orbital ATK uncrewed resupply spacecraft Cygnus and its third flight to the International Space Station under the Commercial Resupply Services contract with NASA. With the Antares rocket undergoing a redesign following its failure during the Orb-3 launch, OA-4 was launched by an Atlas V rocket. Following three launch delays due to inclement weather beginning on 3 December 2015, OA-4 was launched at 21:44 UTC on 6 December 2015. With a liftoff weight of 7,492 kilograms, OA-4 became the heaviest payload ever launched on an Atlas V. The spacecraft rendezvoused with and was berthed to the ISS on 9 December 2015. It was released on 19 February 2016 after 72 days at the station. Deorbit occurred on 20 February at approximately 16:00 UTC.Cygnus Enhanced Details
United Launch Alliance (ULA) is a joint venture of Lockheed Martin Space Systems and Boeing Defense, Space & Security. ULA was formed in December 2006 by combining the teams at these companies which provide spacecraft launch services to the government of the United States. ULA launches from both coasts of the US. They launch their Atlas V vehicle from LC-41 in Cape Canaveral and LC-3E at Vandeberg. Their Delta IV launches from LC-37 at Cape Canaveral and LC-6 at Vandenberg.INFO WIKI