First ever commercial space cargo flight takes off
22 May 2012 Last updated at 20:05 BST
The head of Nasa has hailed a "new era" in exploration after the launch of the first cargo delivery to the space station by a private company.
The Falcon rocket, topped by an unmanned Dragon freight capsule, lifted clear of its Florida pad at 03:44 EDT (07:44 GMT; 08:44 BST).
The launch system has been built by California-based firm SpaceX.
The BBC's Science Correspondent Pallab Ghosh explains.