UPDATE: The launch has been called for a second time this week, after the rocket experienced another dangerous fuel leak.

The first attempt on Monday was also marred by escaping hydrogen, but those leaks were elsewhere on the 322ft (98-metre) rocket.

PA has reported that launch director Charlie Blackwell-Thompson and her team tried to plug today's leak the way they did the last time: stopping and restarting the flow of super-cold liquid hydrogen in hopes of removing the gap around a seal in the supply line.

They attempted this twice, and also flushed helium through the line. However, Ms Blackwell-Thompson finally halted the countdown after three to four hours of effort.

There was no immediate word on when NASA might try again. After Tuesday, a two-week launch blackout period kicks in.

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Space scientists from Cornwall are watching with baited breath as NASA prepares to make a second attempt at launching its latest rocket to the moon today (Saturday).

It had been hoping to launch on Monday this week, but this had to be abandoned shortly before lift-off due to a temperature problem in one of the engines.

The flight is the first in the space agency's Artemis programme, and will be flying without a crew for this first mission.

However, the plans is for astronauts to be on board for subsequent missions, with the first crewed flight into space scheduled for 2024.

NASA then hopes that the first Artemis astronauts will land on the moon in 2025 – the first time in more than half a century.

And right in the centre of the action will be Goonhilly Earth Station on the Lizard Peninsula, which will be providing communications support for the mission and tracking its progress.

It will be working with the European Space Agency (ESA) in tracking some of the mission's CubeSats – miniature satellites that carry out research work.

NASA is hoping for a second go at launching Artemis 1, which can again be watched live online via the NASA Live stream on YoutTube - see below. There will also be build up throughout the day. 

It is looking at a launch time of around 7.17pm UK time, with a two-hour launch window.

NASA scientists are looking carefully at the weather conditions, with possible showers and potentially thunder forecast for the Kennedy Space Centre in Florida, where the launch will take place. However, meteorologists with the US Space Force Space Launch Delta 45 have given a 60% chance of being favourable enough

In a press conference last night it was revealed that on any given day there is a one in three chance that a mission will be 'scrubbed', and of that it is 50% likely that it will be due to weather.

Should the launch go ahead as planned, it is now expected to land on October 11 - only a day later than planned.

This is because what had previously been expected to be 42-day mission has been reduced to 37 or 38 days, with the rocket travelling 1.3 million miles in this time.

Should today's launch be cancelled again, there are also windows of opportunity on Monday and Tuesday.

 

PA Graphics/NASA

PA Graphics/NASA

 

The 322ft (98m) tall Space Launch System (SLS) rocket, which is the world’s most powerful rocket to date, is due to take the Orion capsule, powered by the Airbus-built European Service Module (ESM), into the moon’s orbit.

The flight, which will carry mannequins rather than astronauts, marks the next chapter in putting humans back on the moon.

The UK is part of the Artemis programme, making contributions to the Lunar Gateway – a space station currently in development with the European Space Agency – working alongside the US, Europe, Canada and Japan.

The latest mission is about proving people can make longer and more sustainable trips there. It will also assess whether some infrastructure can be built on and around the moon, allowing humans to survive on another planetary body.

 

PA Graphics/NASA

PA Graphics/NASA