SpaceX’s Starship Explodes During Test Flight Landing

But within minutes, after a video feed showed a fireball at the instant of touchdown, Mr. Musk posted a follow-up tweet explaining that low fuel pressure “during the landing burn contributed to the high touchdown velocity and the massive explosion.”

Still, the company’s founder and chief technical officer added there was good news because the team “got all the data” it needed during the mission. “It appears everything is in order for future tests,” he said.

Weeks before launch, Mr. Musk had sought to tamp down expectations by predicting a 1-in-3 chance of success for the test of the reusable craft, which uses a complex midair maneuver that flips it from nose-down to a final nose-up descent. That abrupt movement—which industry officials say hasn’t been successfully executed before by any other big booster—is one of the most challenging aspects of Starship’s flight profile. Preparing for the flight, Mr. Musk promised the company would show real-time footage of the test, “warts and all”—something he had eschewed for some earlier Starship tests.

On average, one out of the first three launches of new rockets have ended in failure over the past few decades

On Wednesday, a trio of engines boosted the vehicle to its planned altitude, before navigation and flight-control systems, as expected, reoriented it for a vertical landing attempt near the company’s manufacturing and testing facility in southern Texas. The day before, the flight was scrubbed just before liftoff because of an automated engine warning.

Earlier versions of the gleaming stainless-steel spaceship—intended to transport people to the moon and eventually Mars—previously performed much simpler short hops, reaching an altitude of barely 500 feet. Space Exploration Technologies Corp., the company’s formal name, also suffered a string of engine problems, structural failures and other technical setbacks before Wednesday’s liftoff.

Despite the botched touchdown, the suborbital mission highlighted the capabilities of the latest-version Starship, a hulking combination of capsule and rocket, which is 30 feet in diameter and features rakish fins near the nose and longer flaps at the base. Previous versions were tested without a nose cone.

Starship has gone through dramatic design changes over the years, even as Mr. Musk continues to predict significantly faster progress for his program compared with U.S. government plans to send astronauts to the Red Planet by the 2030s.

At various times Mr. Musk has said SpaceX foresees sending a Starship, with or without people on board, around Mars within a handful of years. But industry and government space officials consider that overly optimistic. A number of other prototypes already have been built or are in fabrication, and Mr. Musk has talked about ultimately sending as many as 100 people on a single Starship voyage.

In the wake of the mishap, SpaceX’s chief reiterated his upbeat assessment of the overall test. “Mars, here we come,” Mr. Musk said in a succinct, separate tweet.

The privately held Southern California company hasn’t publicly spelled out a financing plan or detailed technical milestones. Before humans can be carried inside, life-support systems need to be developed and vetted.

For Mr. Musk, managing the Starship project and development of SpaceX’s production, test and launch facility in Boca Chica, Texas, have become consuming tasks. On Tuesday, during The Wall Street Journal’s annual CEO Council event, Mr. Musk said he had personally relocated to Texas partly to oversee progress on Starship. He cited work on the space project and a new factory to build Tesla vehicles in the Austin area as “the two biggest things that I’ve got going on right now.” Mr. Musk also runs electric-car maker Tesla Inc.

SpaceX’s accomplishments have vaulted the company to the top tier of commercial and government launch providers, prompting intense industry interest in Starship’s development. To reach the moon or penetrate deeper into the solar system, Starship is designed to sit on top of another, giant rocket that SpaceX also is developing.

That rocket, slated to have roughly 30 engines, is called Super Heavy; it hasn’t yet flown. The Starship-Super Heavy combination, potentially able to lift some 150 tons into low-Earth orbit, could become a building block of NASA’s Mars-exploration program, depending on future White House priorities. The rocket’s propulsion and guidance systems also will have to be checked out on missions without people on board.

At one point, SpaceX’s focus on Starship elicited complaints from Jim Bridenstine, head of the National Aeronautics and Space Administration, that Mr. Musk was scrimping on a NASA contract to ferry astronauts to the International Space Station. But with two successful astronaut missions to the orbiting laboratory this year, Mr. Musk has signaled the company is stepping up efforts to push deep-space initiatives.

Write to Andy Pasztor at [email protected]