Elon Musk’s SpaceX has called off Monday’s scheduled launch of the most powerful rocket ever built.
The company hoped the short but highly-anticipated launch from Texas would be the initial step on a human journey back to the moon and eventually Mars.
The two-stage rocketship, standing taller than the Statue of Liberty at 394 feet high, was due for blastoff shortly after 2pm BST on Monday.
However Mr Musk flagged it was likely to be called off in a tweet posted at 2.11pm.
“A pressurant valve appears to be frozen, so unless it starts operating soon, no launch today,” he said.
A pressurant valve appears to be frozen, so unless it starts operating soon, no launch today
— Elon Musk (@elonmusk) April 17, 2023
He added that a lot had been learned.
Another launch attempt is not expected for at least 48 hours, with the billionaire saying there will be a retry in "a few days".
The countdown was halted at the 40-second mark because of a stuck valve in the first-stage booster.
It then continued, and fuelling was completed, as a dress rehearsal.
The stainless steel Starship is 120 metres tall, has 33 engines and 16.7 million pounds of thrust.
SpaceX says Starship will be able to carry up to 100 people on long-duration interplanetary flights.
It will also enable the delivery of satellites and the development of a moon base, and point to point transport on Earth - allowing travel to anywhere in the world in one hour or less.
Super Heavy is the first stage of the launch system and is fully reusable and is designed to re-enter Earth’s atmosphere to land back at the launch site.
However, the test flight on Monday would have seen it make a water landing.
The launch was due to take place from SpaceX’s Starbase in the US state of Texas, and make a water landing.
Commenting ahead of the launch, British astronaut Tim Peake said: “SpaceX really is thinking big with Starship.
“This is the biggest and most powerful rocket ever built.
“But its ambition goes way beyond its gargantuan size: it is hoped that the rocket will herald a new era of deep space exploration, unlocking the potential for humans to visit other planets.
“This programme could be the launchpad for hugely exciting scientific research.
“I’m convinced that collaboration with commercial operators like SpaceX is vital for pushing the boundaries and enabling this new era of deep space exploration.”
