Dragon Cargo Spacecraft Arrives at ISS

View of Dragon on approach to the ISS, just before grappling with the robotic arm.

SpaceX's Dragon cargo spacecraft has arrived at the International Space Station and was caught by the robotic arm just a couple of hours ago at 4:52 a.m. Mountain time. This was the 4th Dragon mission to the ISS by SpaceX. The craft will be docked at the US Harmony module, where astronauts will unload its supplies and experiments and eventually load it with items needing return to NASA engineers on the ground. The Dragon is the only robotic cargo ship that safely returns to the Earth. The US Cygnus, European ATV, and Russian Progress vehicles all terminate their missions by burning up in the atmosphere. Dragon will spend 4 weeks docked to the station before ending its mission. On this trip, besides all the regular supplies of fuel, water, food, and small experiments, the Dragon also brought up an experimental 3D printer that astronauts will use to create certain parts  for maintenance while in orbit.