SpaceX on Monday postponed the first test flight of Starship, the most powerful rocket ever built, designed to send astronauts to the Moon and Mars and beyond.

Liftoff of the giant rocket was called off just minutes ahead of the scheduled launch time because of a pressurization issue in the booster stage, SpaceX officials said.

SpaceX said the launch will be delayed for at least 48 hours.

Starship had been scheduled to blast off at 8:20 am Central Time (1320 GMT) from Starbase, the SpaceX spaceport in Boca Chica, Texas.

The US space agency NASA has picked the Starship spacecraft to ferry astronauts to the Moon in late 2025 – a mission known as Artemis III – for the first time since the Apollo program ended in 1972.

Starship consists of a 164-foot (50-meter) tall spacecraft designed to carry crew and cargo that sits atop a 230-foot tall first-stage Super Heavy booster rocket.

SpaceX officials said the flight was postponed because of a pressurization issue with the Super Heavy booster.