The SpaceX prototype upper stage built as a pathfinder for SpaceX's planned human-rated Starship rocket literally blew its top Wednesday during a pressurization test. The explosion blasted what appeared to be an upper bulkhead high into the air above the company's seaside Boca Chica, Texas launch complex.

The winged rocket stage, which was being tested without its conical nose section, remained upright on its test stand as billowing vapor from a ruptured tank surged out and down the sides of the vehicle before blowing away in the wind. It appeared that a lower bulkhead might have failed as well, but that was not immediately clear. Spectacular footage of the event was captured by LabPadre and posted on YouTube.

In a statement, SpaceX said "the purpose of today's test was to pressurize systems to the max, so the outcome was not completely unexpected. There were no injuries, nor is this a serious setback."

SpaceX founder Elon Musk showed off the Starship prototype, known as the Mark 1, during a September 28 event at the Boca Chica test facility, saying the company planned to launch the vehicle on a test flight within a few months.

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"This thing is going to take off," he said of the Mark 1, "fly to 65,000 feet, about 20 kilometers, and come back and land in about one to two months. So that giant thing, it's going to be pretty epic to see that thing take off and come back. ... It's wild."

The SpaceX statement, however, said a decision was made before Wednesday's test not to fly the Mark 1 "test article" and instead to press ahead with another, more sophisticated prototype designed to reach orbit.

The futuristic-looking Starship is intended to carry passengers and cargo to Earth orbit, the moon and eventually Mars. Powered by six methane-burning Raptor engines, the Starship requires a huge booster known as the "Super Heavy" to reach orbit. The Super Heavy will be powered by up to 37 Raptor engines.

Standing nearly 400 feet tall, the Super Heavy/Starship vehicle eventually will replace SpaceX's entire fleet of Falcon 9 and Falcon Heavy rockets, Musk said, along with the Crew Dragon spacecraft the company is building to carry astronauts to and from the International Space Station.

Along with the Mark 1 Starship in Boca Chica, SpaceX also is building another ship — the Mark 2 — at an industrial park near the Kennedy Space Center in Florida — along with a launch stand at the NASA spaceport. A Mark 3 version will be built at Boca Chica.

In a tweet after the test mishap, Musk said the Mark 3 would be a major upgrade compared to the Mark 1, which "had some value as a manufacturing pathfinder, but flight design is quite different."