SpaceX's Starship spacecraft prototype ended in a fireball while attempting to land following its six-and-a-half-minute test flight, ABC News reported Thursday. 

It was the highest and most complicated flight yet for the rocket that Elon Musk said might transport people to Mars by 2026. On Twitter, he said: "Mars, here we come!!" Despite the crash he considered it a success.

The suborbital launch was to test how the space vehicle's three engines function and how it manages propellant transition, among other system capabilities, SpaceX said.

The latest version - the first one designed with a nose cone, frame flaps and three boosters - was targeting an altitude of up to 8 miles - higher than previous launches.

The spacecraft climbed to its marked altitude but two of its three main thrusters failed during the flight.

Eventually, all three failed and command control tried to perform a "bell flop" maneuver with the rocket falling back to the ground.

SpaceX has launched Starship prototypes in the past - but to just below 500 feet.

Immediately after the crash Musk said the vehicle's fuel header tank pressure was "low during descent," causing "touchdown velocity to be high."

"With a test like this, success isn't measured by completion of specific goals but rather how much we can learn," The Verge quoted SpaceX as saying on its website.

Wednesday's launch followed the company's latest space station supply flight for NASA by three days, and SpaceX's second astronaut flight by less than a month from the Kennedy Space Center.

NASA awarded SpaceX $135 million to help develop Starship, alongside competing spacecraft from rival groups Blue Origin, the space venture owned by Amazon founder Jeff Bezos, and Leidos-owned Dynetics.