The launch of NASA's most powerful rocket Artemis 1 has been postponed following a hydrogen fuel leak.

The rocket is expected to take off from Cape Carneval on Friday after it missed its two-hour launch window on Monday.

Around 40 minutes before the rocket was due to take off from the Kennedy Space Centre in Cape Canaveral, Florida, the space agency said it was encountering an “unplanned stop”.

The rocket launch is meant to mark the first in the agency’s Artemis programme and opens the next chapter of putting humans back on the moon.

NASA Rocket launch postponed after hydrogen leak

The new Nasa moon rocket is seen on Launch Pad 39-B (Brynn Anderson/PA)NASA Artemis 1 rocket launch. Credit: John Raoux/AP

Making the announcement on the live feed, NASA said: “Launch director Charlie Blackwell-Thompson has called a scrub of the attempt of the launch of Artemis 1.

“The issue that came up was an engine bleed which couldn’t be remedied but the rocket is currently in a stable configuration.

“It was mostly tanked but not completely tanked.

“Engineers are now working on a plan to continue gathering data about this particular engine and the bleed that didn’t work out.”

They added that the first opportunity for the next launch attempt will be September 2 depending on how the engine bleed develops.

Although this launch will be uncrewed, astronauts are expected to be on board for subsequent missions, with the first crewed flight scheduled for 2024.

NASA has outlined that the first Artemis astronauts are expected to land on the moon in 2025.

It will be the first launch of the new 322ft tall Space Launch System (SLS) rocket, which the agency says is the world’s most powerful rocket to date.

It will take the Orion capsule, powered by the Airbus-built European Service Module (ESM), into the moon’s orbit.

The mission is expected to last 42 days, 3 hours, 20 minutes, and in total it will travel 1.3 million miles.

The launch was been given a two-hour window from 1.33 pm (British Summer Time) on Monday from NASA's Kennedy Space Center in Florida.

However, controllers halted a fuel operation this morning after there was a liquid hydrogen leak.

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NASA said earlier: “Teams continue to troubleshoot a liquid hydrogen leak at the mating interface with the core stage.

“After manually chilling down the liquid hydrogen as part of troubleshooting efforts, they are in fast fill operations.”

Similar leaks hindered Nasa’s countdown tests in April and June.

Since the launch has been rescheduled, the rocket is expected to take off on either September 2 or 5.