This is the 2nd mission under NASA's Commercial Resupply Service agreement with Orbital Sciences The unmanned Cygnus cargo vessel delivered approximately 1494kg of supplies and science experiments to the International Space Station.
Commercial Resupply Services (CRS) are a series of flights awarded by NASA for the delivery of cargo and supplies to the International Space Station.The first CRS contracts were signed in 2008 and awarded $1.6 billion to SpaceX for twelve cargo Dragon and $1.9 billion to Orbital Sciences for eight Cygnus flights, covering deliveries to 2016. The Falcon 9 and Antares rockets were also developed under the CRS program to deliver cargo spacecraft to the ISS.
The International Space Station programme is tied together by a complex set of legal, political and financial agreements between the sixteen nations involved in the project, governing ownership of the various components, rights to crewing and utilization, and responsibilities for crew rotation and resupply of the International Space Station. It was conceived in 1984 by President Ronald Reagan, during the Space Station Freedom project as it was originally called.