Orbital ATK and NASA jointly developed a new space transportation system to provide commercial cargo resupply services to the International Space Station (ISS). Under the Commercial Orbital Transportation System (COTS) program, Orbital ATK developed Antares™, a new medium-class launch vehicle and the Cygnus advanced maneuvering spacecraft. The COTS demonstration mission was successfully conducted in September 2013.
With the successful demonstration of the COTS system, Orbital ATK commenced regular ISS cargo missions under the Commercial Resupply Service (CRS) program in 2014. Under the CRS contract, Orbital ATK is delivering approximately 28,700 kg. of pressurized cargo over eight missions to the ISS, providing a U.S.-produced and-operated cargo delivery service for the ISS, to complement Russian, European and Japanese ISS cargo vehicles.
The design, manufacture and test of Antares occurs at Orbital ATK locations in Dulles, VA, and Chandler, AZ. Cygnus consists of a Service Module (SM) which is produced and integrated in Dulles ,VA, and a Pressurized Cargo Module (PCM) provided by Orbital ATK's industrial partner Thales Alenia Space. The cargo destined for the space station is loaded into PCM and the two modules are mated together at the launch site. CRS launches occur at NASA's Wallops Flight Facility and at Cape Canaveral Air Station with integrated mission operations conducted from control centers in Dulles,VA and Houston, TX and Tsukuba Japan.
The Cygnus PCM is designed with two configurations. The standard configuration (used for first three CRS missions) carried up to 2,000 kg (4,409 lb.) of cargo, while the enhanced variant (used for OA-4 and subsequent missions) carries up to 3,513 kg (7,733 lb.).