NG-11, previously known as OA-11, is the twelfth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its eleventh flight to the International Space Station under the Commercial Resupply Services (CRS-1) contract with NASA. The mission launched on 17 April 2019 at 20:46:07 UTC. This is the last mission from the extended CRS-1 contract; follow-up missions are part of the CRS-2 contract. Cygnus NG-11 was also the first mission to load critical hardware onto Cygnus within the last 24 hours prior to launch, a new Antares feature.

Cygnus is an expendable American cargo spacecraft developed by Orbital Sciences Corporation but 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 from the Wallops Flight Facility, although three flights were on ULA's Atlas V and three are planned for SpaceX's Falcon 9, in both cases launching from Cape Canaveral Space Force Station. It transports 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.