The US aerospace company SpaceX has successfully landed a resusable rocket on an ocean platform, after four previous attempts failed.
Mission controllers cheered as the Falcon 9 rocket remained upright on the platform off Florida.
It was returning from delivering an inflatable habitat into space for Nasa.
The inflatable room will attach to the International Space Station (ISS) for a two-year test and become the first such habitat to for humans in orbit.
It is due to reach the ISS around 09:00 GMT on Sunday along with other freight aboard the Dragon capsule.
Built by Nevada company Bigelow Aerospace, the habitat is intended to pave the way towards the use of such rooms for long space trips, including to Mars.
Nasa had not attempted a cargo run with SpaceX since a June 2015 mishap, when an unmanned cargo rocket exploded soon after take-off.
The Falcon 9 lifted off on schedule at 16:43 local time (20:43 GMT) on Friday from Cape Canaveral Air Force Station in Florida.
Source : BBC