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, external.
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, external 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.