The safe landing of a first-stage rocket on a barge in the Atlantic, at the fifth attempt marked another significant step forward in the efforts by SpaceX, the space launch provider founded by Elon Musk, to make its rockets truly reusable.

The company had in December successfully made possible the return of a first-stage rocket to land at Cape Canaveral, Florida.

After one of SpaceX’s Falcon 9 rockets carrying supplies to the International Space Station exploded 45km above the Atlantic Ocean, this launch marked SpaceX’s first mission to send one of its Dragon supply craft to the station. The only complete failure of any Falcon 9 launch, the December incident which was a test return to flight following that explosion, was a result of the failure of a strut.

With its engine burning, the first-stage rocket reappearing from the sky 300km north-east of Cape Canaveral after about eight minutes of its take-off, a video showed. The first stage rocket settled upright on the drone barge after the machine extended a set of landing legs. The barge was named as named Of Course I Still Love You by SpaceX.

“Falcon 9 first stage on our drone ship in the Atlantic after propelling the Dragon spacecraft to the Space Station,” SpaceX wrote on Twitter.

SpaceX was immediately congratulated by Nasa, the US space agency, which paid for the mission.

“Congrats to the SpaceX team and Elon Musk! Way to stick the landing and send Dragon to the space station!” it tweeted.

With the intention to bring costs down sharply, SpaceX’s efforts are one of several under way aimed at reusing space launch vehicles. When Blue Origin, the space company of Jeff Bezos, the Amazon founder, landed a rocket back in Texas after a suborbital flight, it became the first company to recover a first-stage rocket last November.

Reusable engines for the first stage for Vulcan are also being developed by Blue Origin. Vulcan is the new rocket being designed by United Launch Alliance which handles all the US’s national security launches.

Since it entails a considerably shorter flight back to earth for the rocket than a return to Florida, SpaceX has persisted with attempts to make recoveries at sea, despite the substantial difficulties. This also translates into the fact that the shorter distance means the rocket has more remaining fuel, which in turn improves its chance of manoeuvring successfully on to the drone ship.

She expected reuse to cut the cost of launches with the Falcon 9 — already cheaper than ULA’s alternatives — by as much as 30 per cent, Gwynne Shotwell, SpaceX’s chief operating officer, said last month.

The low cost of SpaceX;s operations has made it a critical part of the US’s space program. Under an arrangement designed to bring down costs, SpaceX has been carrying cargo to the space station for Nasa, the US space administration since 2010.

Problems related to the extending legs or the rocket hit the barge at the wrong angle, causing it to topple over and explode in previous attempts had caused failures at landing at sea.

(Adapted from cnbc.com)