Cygnus is an expendable American cargo spacecraft developed by Orbital Sciences Corporation and now manufactured and launched by Northrop Grumman Space Systems as part of NASA's Commercial Resupply Services (CRS) program. It is usually launched by Northrop Grumman's Antares rocket, although three flights were on ULA's Atlas V and three are planned to launch on SpaceX' Falcon 9. It is designed to transport supplies to the International Space Station (ISS) following the retirement of the American Space Shuttle. Since August 2000, ISS resupply missions have been regularly flown by the Russian Progress spacecraft, as well as by the European Automated Transfer Vehicle, and the Japanese H-II Transfer Vehicle. With the Cygnus spacecraft and the SpaceX Dragon, NASA seeks to increase its partnerships with domestic commercial aviation and aeronautics industry.