SpaceX on 8 April successfully recovered the first stage of a Falcon 9 rocket on the landing pad of an unmanned ship floating in the Atlantic Ocean.

Coupled with the successful recovery of a Dragon 9 booster stage on land on 21 December, SpaceX has now demonstrated the basic feasibility of recovering the first stage of any rocket launch, whether the payload is intended to be lofted to low-earth orbit, geostationary orbit or proceed to the Moon or another planet, such as Mars.

“I think it’s a good milestone for the future of spaceflight and another step towards the stars,” says SpaceX founder Elon Musk, addressing a press conference at NASA’s launch complex in Cape Canaveral, Florida.

Musk’s mood was celebratory, but measured. He elaborated on the challenges and likely failures that are still to come before recovery of orbital space launchers becomes a routine event.

Although the first ocean recovery marked a historic achievement, the rocket’s payload – an expendable habitat designed by Bigelow Aerospace – is heading to a rendezvous with the International Space Station (ISS) on 10 April.

But the ISS target means the recovered Falcon 9 booster was launched on a low-earth orbit trajectory. It was only the second such recovery in history, but needed to overcome far less velocity and heat than required for a trajectory to a geo-stationary orbit.

Although intended to be a simpler test of the four-engined recovery system, SpaceX engineers still considered the odds of failure to be about one in three, Musk says.

The next two launches on the Falcon 9 manifest involve payloads heading to geostationary orbit, says Musk.

The next challenge will come when SpaceX introduces the Falcon Heavy rocket. The 27-engined booster is intended to launch the heaviest payloads to geostationary orbit, or provide enough thrust to escape earth’s gravity for a trip to the Moon or Mars. Musk says he plans to unveil his detailed plans for establishing a Mars colony in September in Mexico at the International Astronautical Conference.

“It will still take us a few years to make [recovery] smooth and make it efficient. But I think it’s proven it can work,” Musk says. “There’s probably going to be some failures in the future. But we’ll iron those out get it to the point where it’s routine.”