SpaceX launched its shiny, bullet-shaped, straight-out-of-science fiction Starship several miles into the air from a remote corner of Texas on Wednesday, but the 6 ½-minute test flight ended in an explosive fireball at touchdown. This suborbital flight is created to test several objectives, from how the vehicle's three Raptor engines perform to the vehicle's overall aerodynamic entry capabilities (including its body flaps) to how the vehicle manages propellant transition.

"Mars, here we come!" he later tweeted.

SpaceX's latest test flight lifted off at around 2:45 pm on Pacific Time Wednesday afternoon. And the company's engineers have been rather proactive in iterating the design, quickly moving through the building and testing of prototypes, starting with the unveiling of the first version in January previous year, to the 500-ft (150-m) hop test of SN5 a few months ago, to today's flight of SN8.

"With a test such as this, success is not measured by completion of specific objectives but rather how much we can learn, which will inform and improve the probability of success in the future as SpaceX rapidly advances development of Starship", a statement on the company's website said, implying even before the launch that an explosion or crash would not mean a failed mission.

The experimental flights are taking place in a almost deserted part of southern Texas on the Gulf of Mexico near the US-Mexican border - an area empty enough that any flight malfunction would be unlikely to cause physical or property damage. As it neared the ground, the Raptors and thrusters tilted the spacecraft to slow down in preparation for a safe landing.

The event was live-streamed on SpaceX's Youtube channel. There was low pressure during the landing, "causing touchdown velocity to be high & RUD", he wrote, using an acronym for "rapid unscheduled disassembly".

The Starship flight was seen as a major success within the company given that the vehicle remained aerodynamically stable during its ascent, a "belly flop" to orient for landing and its precision approach to the landing pad.

"We got all the data we needed!"

SpaceX is known to embrace fiery mishaps during the rocket development process. The entire vehicle will tower 394 feet (120 meters) - 31 feet (9.4 meters) taller than NASA's Saturn V rocket that hurled men to the moon a half-century ago.

The 16-storey spacecraft is envisioned by the company as the heavy launch vehicle that could take 100 tonnes of cargo and passengers to the moon or Mars.

NASA awarded SpaceX $US135 million ($180 million) to help develop Starship, alongside competing vehicles from rival ventures Blue Origin, the space company owned by Amazon billionaire Jeff Bezos, and Leidos-owned Dynetcis.

Right before Wednesday's launch, NASA announced the 18 USA astronauts who will train for the Artemis moon-landing program.

While one of the three Raptor engines shut down in the first few minutes after liftoff and the second shut down four minutes into flight, Musk affirmed that the engines ran according to plan. But Musk is the first to admit his timelines can be overly optimistic.