SpaceX called off a planned Starship test flight Monday over a frozen valve in the massive rocket's first-stage booster.
The company made the announcement during a live webcast of the launch attempt and switched to a wet dress rehearsal — a test-run of nearly the whole launch process that ends before actual liftoff.
"Learned a lot today," CEO Elon Musk wrote on Twitter. The company later announced it will try again as soon as Thursday morning, with a launch window opening at 8:28 a.m. CT and closing at 9:30 a.m. CT.
In a Twitter "Spaces" event for subscribers Sunday evening, Musk had warned that the company was being cautious and a postponement was possible.
“I guess I’d like to just set expectations low,” Musk said. “If we get far enough away from launch pad before something goes wrong, then I think I would consider that to be a success. Just don’t blow up the pad.”
The company had just gotten a long-awaited license from the Federal Aviation Administration, clearing the way for the unmanned round-the-world test flight — SpaceX planned to send the spacecraft atop the colossal booster from Boca Chica, Texas, all the way to Hawaii. No landings would be attempted; the first stage would be discarded in the Gulf of Mexico and the spacecraft into the Pacific.
It would have been the first launch with Starship's two sections together. Early versions of the sci-fi-looking upper stage rocketed several miles into the stratosphere a few years back, crashing four times before finally landing upright in 2021. The towering first-stage rocket booster, dubbed Super Heavy, will soar for the first time.
The 394-foot rocket was built with the lofty goals of ferrying people to the moon and Mars.
“I’m not saying it will get to orbit, but I am guaranteeing excitement. It won’t be boring,” Musk promised at a Morgan Stanley conference last month. “I think it’s got, I don’t know, hopefully about a 50% chance of reaching orbit.”
A list of countdown stages on SpaceX's website ended with "Excitement Guaranteed."
The Associated Press contributed to this report.