With the countdown clock at the NASA Kenney Space Center Press Site in the foreground, a SpaceX Falcon 9 rocket lifts off from Launch Complex 39A at the Florida spaceport. It was the company's 10th commercial resupply services mission to the International Space Station. Liftoff was at 9:39 a.m. EST from the historic launch site now operated by SpaceX under a property agreement with NASA. The Dragon spacecraft will deliver about 5,500 pounds of supplies, such as the Stratospheric Aerosol and Gas Experiment (SAGE) III instrument to further study ozone in the atmosphere.