A revolutionary attempt by the SpaceX company to land a leftover rocket booster on an ocean barge has failed.

The bid was made off the coast of Florida after the Falcon rocket carrying a load of supplies to the International Space Station was successfully launched.

SpaceX’s billionaire founder Elon Musk says the first stage of the unmanned rocket made it to the platform floating a couple of hundred miles off Florida’s north-eastern coast.

But he says the booster came down too hard and broke apart. It is the first time anyone tried anything like this.

Mr Musk said: “Close but no cigar this time.” He added that it bodes well for the future.

Normally, the first stages are discarded at sea. Mr Musk said recovering and reusing rockets is essential for bringing down launch costs and speeding up operations.

Once separated from the upper stage of the rocket, the main booster re-ignited as planned for the flyback, according to SpaceX. Touchdown was supposed to occur nine minutes after lift-off.

SpaceX had expected the booster - equipped with fins for guidance and landing legs - to soar as high as 50 to 80 miles before moving down towards the modified barge via automatic engine firings.

The Air Force maintained the ability, as always, to destroy the booster if it strayed off course.

Nasa watched the post-launch drama with keen interest but its biggest focus was on the rocket racing toward the space station and its six inhabitants. The capsule is due to arrive on Monday.

The shipment is needed more than usual because of the recent loss of another company’s supply ship.

Orbital Sciences’s Antares rocket exploded seconds after lift-off in October, destroying the entire payload and damaging the Virginia launch complex. That rocket is grounded until next year.

Nasa is paying SpaceX and Orbital Sciences to keep the space station stocked. Russia and Japan also plan supply runs this year.