SpaceX said that its rocket appeared to have broken a landing leg as it came down hard during an attempt to make world-first landing on a floating platform in the ocean.

The space company, owned by Elon Musk, said it had successfully sent a scientific NASA satellite into space but the return was less smooth.

Less than an hour earlier, the rocket has blasted off from California to launch a satellite designed to monitor changes in the sea.

The ambitious landing attempt on a floating barge came a month after the company attained another spaceflight first with a successful ground landing in Florida.