Media playback is unsupported on your device Media caption The first specially designed espresso machine is on its way to the ISS

SpaceX has narrowly failed in its latest bid to retrieve a rocket booster intact, after a successful launch.

The US rocket made it back to an ocean platform but landed "too hard" to survive, SpaceX CEO Elon Musk tweeted.

The capsule borne by the rocket is heading to the International Space Station (ISS), carrying groceries - including an Italian espresso maker.

By retrieving rockets and recycling them, Nasa contractor SpaceX hopes to slash the cost of space travel.

A later tweet by Mr Musk said the rocket had apparently "landed fine, but excess lateral velocity caused it to tip over post landing".

Images accompanying the tweet appeared to show the rocket toppling over on the platform.

Despite this, the company will be hugely encouraged. The experimental work is making progress.

The firm hopes a successful landing would demonstrate that normally disposable rockets can be refurbished and reused.

It could also point to new ways of bringing spacecraft back down to Earth in general.

Image copyright Spacex Image caption The booster finds the platform and is vertical and slowing on approach

Image copyright SPACEX Image caption The Falcon first-stage very nearly pulls it off

Image copyright Spacex Image caption "Excess lateral velocity caused it to tip over post landing"

Image copyright Spacex Image caption The platform, 300km north-east of the Cape, was slightly damaged in a previous landing attempt

In January, the first attempt to land the leftover rocket on the ocean platform ended in a fiery explosion when the booster again hit the platform too hard.

Another attempt, in February, was called off because of choppy waters - but the rocket did practise its manoeuvres by slowing itself to a hover over the ocean.

The Falcon 9 rocket, carrying the capsule nicknamed Dragon, launched from Cape Canaveral air force station in Florida on Tuesday afternoon.

The supply ship, carrying more than 4,000 lbs (1,800 kg) of groceries and equipment for the orbiting laboratory, is expected to reach its destination on Friday.

SpaceX was hired by US space agency Nasa to supply the ISS after the retirement of the space shuttle.