A SpaceX Falcon 9 rocket blasted off from Florida on a NASA cargo run to the International Space Station on Friday, and its reusable main-stage booster landed on an ocean platform minutes later in a dramatic spaceflight first.The successful autonomous touchdown of the booster at sea marked another milestone for billionaire entrepreneur Elon Musk and his privately owned Space Exploration Technologies in the quest to develop a cheap, reusable rocket, expanding his edge in the burgeoning commercial space launch industry.The liftoff at 4:43 p.m. EDT (2043 GMT) from Cape Canaveral Air Station also marked the resumption of resupply flights by SpaceX for NASA following a launch accident in June 2015 that destroyed an earlier cargo payload for the space station.
