Bruce Murray Space Image Library

Commercial cargo shadowplay

Commercial cargo shadowplay
Commercial cargo shadowplay Jeff Williams / NASA

Sunlight and shadows filter through the solar array of an Orbital ATK Cygnus spacecraft onto the hull of a SpaceX Dragon capsule, shortly before Dragon was released from the International Space Station on May 11.

Later that day, Dragon de-orbited and splashed down in the Pacific Ocean, bringing one-and-a-half metric tons of cargo back to Earth. The return manifest included blood, urine and saliva samples from astronaut Scott Kelly, who recently spent a year in space undergoing experiments to help scientists understand how spaceflight affects the human body.

Dragon's arrival at the ISS on April 10 marked the first time two commercial cargo vehicles vehicles were simultaneously berthed to the orbital outpost.