SpaceX's mega rocket blasted off on another test flight Thursday, aiming to make it halfway around the world this time.

Starship, the biggest and most powerful rocket ever built, soared from the southern tip of Texas near the Mexican border and headed out over the Gulf of Mexico. No people or satellites were on board.

Minutes later, the booster separated seamlessly from the spaceship and splashed down into the gulf. The spacecraft continued on its flight eastward, reaching an altitude of 100 miles (160 kilometers) and approaching orbital speed -- outperforming the previous attempts.

The first two flights last year lasted mere minutes before blowing up over the Gulf of Mexico.

The rocket and futuristic-looking spacecraft towers 397 feet (121 meters), easily exceeding NASA's past and present moon rockets.

SpaceX's Elon Musk was shooting for a shorter, hourlong flight on the latest demo, with the Indian Ocean as the spacecraft's finish line. He noted that the company made thousands of upgrades and fixes to improve the odds.

NASA watched with keen interest: The space agency needs Starship to succeed in order to land astronauts on the moon in the next two or so years. This new crop of moonwalkers -- the first since last century's Apollo program -- will descend to the lunar surface in a Starship, at least the first couple times.

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