Shortly afterward, the 20-story-tall Super Heavy booster return to the launch site where it was "caught" by a special launch tower nicknamed "Mechazilla" after the Mechagodzilla robot created by aliens to destroy Godzilla in the famed film franchise.

"This is absolutely insane!" SpaceX engineer Kate Tice said on the live stream.

That maneuver has already been heralded as a breakthrough in sustainability heralding a new future for spaceflight. But the star of the performance was the splashdown procedure for the Starship spacecraft after reaching space during its hourlong flight.

"Starship is in a subsonic belly flop," SpaceX posted on Musk's X platform, formerly Twitter. Later, the company confirmed the splashdown and called the results of the test flight "exciting."

The company previously called Flight 4 a "tremendous success." That launch had included a fully successful ascent followed by the first-ever booster soft-landing in the Gulf of Mexico and Starship making it through a brilliant re-entry.

"Congratulations to @SpaceX on its successful booster catch and fifth Starship flight test today!" NASA administrator Bill Nelson said on X.

"As we prepare to go back to the Moon under #Artemis, continued testing will prepare us for the bold missions that lie ahead -- including to the South Pole region of the Moon and then on to Mars."