SpaceX completes another successful launch of massive rocket — accompanied by another explosion after landing

The third test of SpaceX's Starship rocket, that CEO Elon Musk hopes will one day ferry humans to Mars, launched from Boca Chica, Texas, on Wednesday, and touched down softly, but exploded shortly thereafter.

The 50-metre rocket, dubbed SN10, or serial number 10, reached a planned altitude of 10 kilometres before beginning its descent — what space-watchers call the "belly flop."

It then approached the landing pad and fired rockets to reorient itself into a vertical position. But it exploded shortly after landing.

An earlier launch attempt in the afternoon was aborted with less than a second to go due to a concern over thrust readings.

There was no immediate comment from SpaceX on what went wrong.

Later Wednesday, Musk tweeted that "Starship SN10 landed in one piece!"

In a separate comment on Twitter, he commended the SpaceX team for "doing great work."

There are several more Starships ready for more test launches, with SN11 already in the high bay area at the launch site in Boca Chica.

Eventually, the second part of the rocket, the Super Heavy, will also undergo tests. Collectively, they will be referred to as Starship.

Once Starship and the Super Heavy are paired, it will stand 120 metres, taller than the Saturn V rocket that took astronauts to the moon.

Musk has said that he plans to use Starship to take astronauts to the moon and eventually to Mars.

SpaceX already has its first private passenger, Japanese billionaire Yusaku Maezawa. On Tuesday, Maezawa announced a search for eight people to join him on the trip around the moon, which will be on Starship.