On December 09, 2015 the American "Cygnus” (CRS OA-4, “Deke Slayton II”) private unmanned supply spacecraft was docked to the International Space Station (ISS). The Cygnus spacecraft was grappled by a robotic arm operated by astronauts inside the space station at 11:19 UTC. The cargo spacecraft was docked to the station’s "Unity” module at 14:26 UTC. The spacecraft delivered 3200 kilograms of supplies to the Space Station. It was the 4^th docking of a "Cygnus” spacecraft with the ISS.