SpaceX on Saturday made progress in the second test launch of its mammoth Starship rocket, with the booster separating from the spaceship, but both then exploding shortly after over the ocean.

"Such an incredibly successful day," a SpaceX announcer said. "Even though we did have a… rapid unscheduled disassembly of both the Super Heavy Booster and the ship."

The largest rocket ever built—Elon Musk hopes it will one day be used to colonize Mars—blasted off from the company's Starbase in Boca Chica, Texas shortly after 7:00 am local time (1300 GMT).

Unlike the previous such attempt in April, the booster rocket separated successfully from the mega ship, but then blew up, followed shortly by the spaceship itself.

Bill Nelson, head of the NASA space agency, which is awaiting a modified version of Starship to land humans on the Moon, said Saturday's attempt showed progress.

SpaceX launched its mega rocket Starship but lost both the booster and the spacecraft in a pair of explosions minutes into Saturday's test flight.

The rocketship reached space following liftoff from South Texas, but communication suddenly was lost. SpaceX officials said it appears the ship's self-destruct system blew it up over the Gulf of Mexico.

The flight came to an end as the ship's engines were almost done firing to put it on an around-the-world path. The first test flight in April also ended in an explosion.

On Saturday, about three minutes into flight, the separated booster also exploded over the gulf. By then, though, its job was done.