By Joe Skipper and Steve Gorman

BOCA CHICA, Texas (Reuters) -SpaceX’s next-generation Starship spacecraft exploded minutes after liftoff in an uncrewed test flight from South Texas on Thursday, cutting short a key step in Elon Musk’s development of a rocket vessel to eventually take humans to the moon and Mars.

The flight test was the first for Starship mounted atop the company’s new Super Heavy rocket, and the first launch ever for that lower-stage booster, which SpaceX has touted as the most powerful launch vehicle on Earth.

Even though the two-stage rocket ship made it less than halfway to the edge of space, climbing to just under 25 miles (40 km), the flight achieved a primary objective of getting the new vehicle off the ground at liftoff despite some of its engines failing.

While SpaceX officials were heartened by the outcome, the mission fell short of reaching several objectives.

The plan was for Starship to soar into space at least 90 some miles (150 km) above Earth before it would re-enter the atmosphere and plunge into the Pacific near Hawaii.

But SpaceX said in a statement afterward that the spacecraft “experienced multiple engines out” during its ascent, then “lost altitude and began to tumble,” before the “flight termination system was commanded on both the booster and the ship.”

Musk, SpaceX’s founder, chief executive and chief engineer, had appeared eager to temper expectations in remarks made Sunday that downplayed the odds of a successful first flight. SpaceX President Gwynne Shotwell told a conference in February that the “the real goal is to not blow up the launch pad.”

    By that measure, the debut flight of Starship with its booster rocket represented a milestone in SpaceX’s ambition of sending astronauts back to the moon and ultimately to Mars, as a major partner in Artemis, NASA’s newly inaugurated human spaceflight program.

NASA chief Bill Nelson congratulated SpaceX on Twitter, saying, “every great achievement throughout history has demanded some level of calculated risk, because with great risk comes great reward.”

LAUNCH, THEN FIERY ‘DISASSEMBLY’

The two-stage rocket ship, standing taller than the Statue of Liberty at 394 feet (120 meters), blasted off from the company’s Starbase spaceport on the southern tip of Texas along the Gulf Coast east of Brownsville. SpaceX hoped, at best, to pull off a 90-minute debut flight into space but just shy of Earth orbit.

A live SpaceX webcast showed the rocket ship rising from the launch tower into the morning sky as the Super Heavy’s Raptor engines roared to life in a ball of flame and billowing clouds of exhaust and water vapor.

But less than four minutes into the flight, the upper-stage Starship failed to separate as designed from the lower-stage Super Heavy, and the combined vehicle was seen tumbling end over end before blowing apart.

The pad and surrounding area were cordoned off well in advance of the test, SpaceX said. Any debris from the explosion should have landed over the water in areas placed off-limits by the U.S. Coast Guard.

The spacecraft reached a peak altitude of about 24 miles (39 km) before its fiery disintegration, SpaceX said. The company also noted that the rocket reached the critical launch point of maximum aerodynamic pressure before appearing to lose control.

SpaceX officials on the webcast hailed the liftoff as a welcome accomplishment.

A throng of SpaceX workers shown during the webcast watching a livestream together at the company’s headquarters near Los Angeles cheered wildly as the rocket cleared the launch tower – and again when it blew up.

‘LEARNED A LOT’

Musk, shown seated in the Starbase mission control room in Boca Chica, Texas, wearing a headset, said on Twitter afterwards that the next Starship test launch would be in a few months.

“Congrats @SpaceX team on an exciting test launch of Starship! Learned a lot for next test launch,” he tweeted. Musk, who purchased Twitter last year for $44 billion, is also CEO of electric carmaker Tesla Inc.

SpaceX principal integration engineer John Insprucker, one of the webcast commentators, said the experience would provide a wealth of data to inform further flight tests.

The road to Thursday’s accident has not been without previous tests and setbacks.

A stationary test firing of the Super Heavy while bolted to a platform managed to ignite just 31 Raptor engines in February, and an earlier static firing test in July 2022 ended with the vehicle’s engine section exploding.

Before that, SpaceX had test-launched prototypes of Starship’s top half in five short flights to an altitude of 6 miles (9.7 km), seeking to perfect its return landing capability. All but one crashed in flames.

The spectacular nature of Thursday’s loss of the first fully integrated Starship-and-booster vehicle during its introductory launch further highlighted challenges SpaceX faces moving beyond its workhorse Falcon 9 rocket, the centerpiece of the company’s satellite launch business.

Still even a textbook test flight would have by design ended with crash landings of both portions of the spacecraft at sea.

The Super Heavy and Starship were each designed as reusable components, capable of flying back to Earth for soft landings in a maneuver that has become routine in dozens of missions for SpaceX Falcon 9 rockets.

For Thursday’s launch, however, the flight plan called for the lower stage to fall into the Gulf of Mexico after separating from the upper stage, which would have come down in the Pacific Ocean near Hawaii after achieving nearly one full Earth orbit.

(Reporting by Joe Skipper in Boca Chica, Texas; Writing and additional reporting by Steve Gorman in Los Angeles; Additional reporting by Joey Roulette in Colorado Springs, Colorado; Editing by Frank McGurty and Jonathan Oatis)

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