As a Falcon 9 rocket stands ready for liftoff at the Kennedy Space Center's Launch Complex 39A. The rocket will boost a Dragon resupply spacecraft to the International Space Station. Liftoff is scheduled for 12:31 p.m. EDT. On its 12th commercial resupply services mission to the space station, Dragon will bring up more than 6,400 pounds of supplies. The historic launch site now is operated by SpaceX under a property agreement signed with NASA.