During its brief first flight just over a week ago, the giant Starship rocket built by SpaceX produced an unexpected “tornado of rock” on launch, with multiple engines failing on its way up before it flipped out of control.
Then, in an update posted in a Twitter audio chat on Saturday night, company founder Elon Musk said the flight ended more nervous than it should have been. The automatic self-destruct order did not immediately destroy the starship. Instead, 40 seconds passed before the rocket finally exploded.
Despite all the problems, Musk considered the Starship launch a success.
“Obviously not a total success,” he said, “but a success nonetheless.”
He said the purpose of the test flights was to “learn a lot, and we learned a lot,” with more test flights planned for this year.
The spacecraft, the most powerful spacecraft ever launched, is critical to SpaceX’s goal of sending humans to Mars and to NASA’s plan to return astronauts to the Moon by 2025 as part of the Artemis program.
While the rocket didn’t make it to space, “the results were roughly in line with my expectations, maybe a little bit beyond my expectations,” Mr. Musk said, noting that it “went off the launch pad with minimal damage to the launch pad.”
At the same time, he admitted that the launch threw large area of debris And created a cloud of dust that reached a small town in the southern tip of Texas a few miles from the launch pad.
In a Twitter discussion that lasted nearly an hour, Mr. Musk answered esoteric technical questions and provided a detailed timeline of what went wrong during the four-minute flight.
Three of the 33 engines in the Starship booster stage shut down before the rocket left the launch pad.
“The system didn’t think they were healthy enough to get the best out of them,” Mr. Musk said, “so they were turned off.”
The loss of three engines caused the starship to tip to one side as it traveled upwards. “We generally don’t expect to be lean,” Mr. Musk said. “It should actually go straight up.”
Twenty-seven seconds after launch, one of the engines failed — “some kind of energy event,” Mr. Musk said — which damaged several other nearby engines.
“Still, the rocket keeps going,” Mr. Musk said. After 85 seconds of flight, the rocket lost the ability to control its direction by pointing at the nozzles of the engines, and “it really happened to the fans,” Mr Musk said.
Since then, the rocket began flying out of control, and continued even after the order was terminated.
“It took too long to break the tank,” Mr. Musk said of the flight termination system, which is designed to destroy a runaway rocket. The delay really is a testament to the resilience of the rocket, which survived the fall intact.
“The structural margins on the car appear to be better than we expected,” Mr. Musk said.
For the next launch, more explosives can be added to ensure that “if the flight needs to be terminated, the rocket will explode immediately,” he said.
Another unexpected surprise was the shattering of concrete beneath the rocket during launch.
The thrust of 30 engines unexpectedly created a “rock tornado” that scattered debris over hundreds of acres and created a huge cloud of dust.
“Basically a man-made dust storm,” Mr Musk said. “But we don’t want to do that anymore.”
The rocket’s 33 engines will not fire directly into the concrete below the rocket when it lifts off, but instead will be fitted with a large water-cooled steel plate. Mr. Musk said the board was not yet ready for last week’s launch.
He said the next rocket and repairs to the launch pad would be ready in six to eight weeks. Still, the FAA, which oversees rocket launches, is investigating the events of the first launch and must be satisfied with SpaceX’s tweaks and improvements before allowing another Starship flight.
The next launch will attempt to accomplish the goals of the first mission — successfully separating Starship from the booster and reaching space, before circling most of Earth and landing in the ocean near Hawaii.
Mr. Musk did not promise that the second attempt would be completely successful. He said he expects four or five more Starship launches this year. “This year we probably have an 80 percent chance of reaching orbit,” Mr. Musk said. “I don’t want to test fate, but I think the probability of reaching orbit within 12 months is close to 100 percent.”
Mr Musk said SpaceX, which spent “around $2 billion” on Starship this year, did not require additional investment to develop the rocket.
One of Starship’s primary uses is as a lunar lander on NASA’s Artemis III mission, which takes astronauts to the lunar surface near the South Pole. Mr. Musk confidently asserted that Starship would be ready before other components, such as the Space Launch System rocket, were built by NASA. “We’re not going to be a limiting factor at all,” he said.
He also highlighted the technical challenges SpaceX is trying to overcome in producing a giant spacecraft that can fly repeatedly and rapidly, more like a jetliner.
“This is certainly a candidate for the hardest technical problem ever done by humans,” Mr. Musk said.