There's just an hour to go until the launch window opens for Nasa's first crewed mission around the Moon in more than 50 years - watch live above
Nasa is troubleshooting an issue with the launch abort system battery, it says, after an earlier issue with an onboard safety mechanism was resolved
Glitches aren't unusual for launches, our science editor writes, but it's a bit nerve-jangly that problems are cropping up so close to the launch window
Meanwhile, the four astronauts have been sealed in aboard the spacecraft ahead of launch - find out more about them
The crew on the 10-day Artemis II mission won't land on the Moon, but plan to circle it, while travelling further from Earth than anyone has ever been before
They will do it all in a capsule the size of a minibus - take a closer look at their spacecraft and rocket here
Listen on BBC Sounds:Follow the Artemis II mission with the BBC's space podcast, 13 Minutes
Rebecca Morelle
Science editor, reporting from the launch
After such a smooth countdown, the last hour has been a bit of a roller-coaster ride.
But glitches aren't unusual for launches - in fact there are normally loads more.
It's just a bit nerve-jangly that the problems are cropping up so close to the launch window opening.
Esme Stallard
Science reporter
After years of planning, designing and testing we are into the final hour before the launch of the Artemis II mission.
The final hatch is now closed on the launch abort system that will evacuate the astronauts in the event of an emergency.
We can see that the "close out" crew are about to leave the launchpad.
But they are still testing all the systems, and Nasa have just said it is now investigating a battery temperature issue.
It really is nail-biting stuff right into the closing minutes.
Leyla Khodabakhshi
Reporting from the launch
There is a sense of calm here at Kennedy Space Center - at least for now.
People are still gathering around the countdown clock, watching the time tick down and waiting for what comes next.
In the press area, journalists are taking their positions, checking equipment and preparing for the moment the launch begins.
For now, it is quiet anticipation.
Esme Stallard
Science reporter
Image source, ReutersWe have just heard from the Nasa team on the ground - and we are now "go for launch".
Relief all around - we can hear cheers on the live feed from those watching at the space centre.
Nasa confirmed that the solution they were testing using old hardware from the previous Space Shuttle programme has got the termination system working.
It has also said that the weather conditions have become more favourable with the clouds moving away. This is important as there is a risk of lightning with their presence.
Some types of cloud, even though they do not produce lightning, carry an electrical charge where a rocket passing through them at high speeds can trigger a strike.
The final hatch has just been closed.
Rebecca Morelle
Science editor, reporting from the launch
The Nasa team are continuing through the final steps despite the ongoing issue with the termination system.
They are now closing the hatch to the Orion spacecraft.
They’ll be the last people Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen see for the next 10 days.
From here on in it’s just the four of them. But luckily they get on brilliantly - it’s clear how well they know, and like, each other when you see them together.
They’ve even said they have got to the point where they know what the others are thinking - so close has become their bond.
Image source, NASA
Pallab Ghosh
Science correspondent, reporting from the launch
More now on that flight termination system issue.
This is the onboard safety mechanism that would deliberately destroy the rocket if it veered off course, to prevent debris from endangering people or property downrange.
Ground controllers have a communication issue with the system and cannot yet test the system hardware ahead of launch.
The issue is at ground level and engineers are trying to solve it by using some hardware originally used to communicate with the Space Shuttle.
If they are not able to solve the issue within the launch window the launch will be no go. But the countdown procedure is continuing.
Image source, ReutersEsme Stallard
Science reporter
In the last few minutes we have heard there is a problem with the termination system, identified in pre-launch testing.
This is the system that will destroy the rocket in flight if it goes off track, to prevent it from harming anyone on Earth.
At the moment the team are continuing with the other system checks whilst they try to figure this out - but if they cannot get the termination system to work the launch will not happen.
We will bring you more on this as soon as we have it.
The Visual Journalism Team
BBC News
The launch window is now just two hours away. Lets take a look at the rocket that will be taking the Artemis II crew into space:
The Artemis II astronauts will begin the mission on Nasa’s rocket, the Space Launch System (SLS). It is the most powerful rocket the US space agency has ever built.
Standing 98m tall (322 ft), the SLS has four engines to provide the power to get off the ground. The core stage is essentially a giant fuel tank, containing more than three million litres of liquid hydrogen and liquid oxygen.
Its job is to carry the Orion spacecraft - which houses the tiny crew module where the astronauts will spend the next 10 days - into space.
SLS has flown only once before, launching in 2022 with no astronauts onboard for the Artemis I mission.
The launch is one of the most dangerous parts of the mission - everything has to go perfectly. But if anything does go wrong during the early stages of the launch, the Launch Abort System, at the very top of the rocket, should propel the astronauts to safety.
Pallab Ghosh
Science correspondent, reporting from the launch
Image source, NASAStrapped into Orion with the astronauts today is a small, smiling stowaway called Rise – a plush Moon in a cap embroidered with stars and a tiny Earth.
It was designed by eight‑year‑old Lucas Ye, a primary school pupil from California in the United States, whose sketch beat thousands of entries in Nasa’s global Moon Mascot design challenge.
Inside the toy, engineers have tucked a micro SD card packed with messages, photos and hopes for the future from children around the world, turning it into a kind of digital time capsule that will loop out to lunar distance and back.
As Rise floats in the cabin once they reach orbit, it will be both a zero‑gravity indicator for the crew and a reminder that this mission is meant to carry more than four astronauts’ ambitions – it is also carrying the dreams of the generation who might one day follow them to the Moon.
The Visual Journalism Team
BBC News
The four Artemis astronauts will be spending 10 days cramped together in a space about the size of a minibus.
The Orion crew module has similarities to the ones used for the Apollo missions 50 years ago, but the interior is very different.
The four seats the astronauts will use during the launch will be packed away for most of the time to give them more room. The weightless environment means they can make use of space that would otherwise be unusable - so the control panel can be on the "ceiling".
Most importantly, there is a toilet tucked away under the floor. It’s not very private but has been designed to overcome the challenges of going to the bathroom in space.
And just above the toilet hatch, there is a step that doubles up as a flywheel exercise machine - the astronauts will each pull on the cable for 30 minutes of resistance and cardiovascular training every day to help counter the physical effects of being in space.
Alison Francis
Senior science journalist
Image source, Getty ImagesJeremy Hansen, Christina Koch, Victor Glover and Reid Wiseman (pictured left to right)
The Artemis astronauts have revealed the personal items they are taking with them on their lunar flyby.
Victor Glover, the mission pilot, a committed Christian and Sunday school teacher, is packing his Bible.
Canadian Space Agency astronaut Jeremy Hansen has four moon pendants. He bought them two years ago and gave them to his wife and children to wear. Now he has collected them back – they will travel with him on his history-making trip.
Commander Reid Wiseman’s choice is very simple. Some notepaper and a pencil. He wants to record his thoughts while looking out at the spectacular views of the Moon and the Earth.
Messages written by her loved ones are in mission specialist Christina Koch’s suitcase. She says having something in her hands that her family have held and taken time composing will carry a very special meaning for her when she’s a long way from home.
Image source, ReutersA man sells t-shirts and other merchandise ahead of the expected launch
Image source, ReutersPeople are gathering near the launch site
Image source, ReutersPeople watch on from Space View Park near the Kennedy Space Center ahead of the expected launch
Image source, AFP via Getty ImagesEarlier we saw the astronauts on their way to the launch pad
Image source, NASAArtemis II will launch from Launch Complex 39B, a pad specially built for larger missions at the Kennedy Space Center.
The first to launch from this complex was Apollo 10, a rehearsal for the mission that would land on the Moon for the first time in 1969.
The proximity to the Atlantic Ocean was chosen for Nasa’s operation strategically. Rockets can head eastwards towards the sea and reduce the risk to population centres.
But by the 1960s, Cape Canaveral, the agency’s primary launching pad in the area, was not enough for the missions being planned. Launch Complex 39B accommodates larger rockets and, according to Nasa, has been improved to support the Space Launch System (SLS) rocket and Orion spacecraft.
We're seeing more images of the crew in the Orion capsule - which is about 5m (15ft) wide and 3m (9ft) high.
There are four seats for the launch. Once in orbit the crew will pack them away to make more room.
Image source, NASA
Image source, EPAUS President Donald Trump has shared a message on his TruthSocial platform ahead of the planned launch.
He says: "For the first time in over 50 YEARS, America is going back to the Moon! Artemis II, among the most powerful rockets ever built, is launching our Brave Astronauts farther into Deep Space than any human has EVER gone.
"We are WINNING, in Space, on Earth, and everywhere in between — Economically, Militarily, and now, BEYOND THE STARS. Nobody comes close! America doesn’t just compete, we DOMINATE, and the whole World is watching."
He also says "God bless" to the astronauts.
Pallab Ghosh
Science correspondent, reporting from the launch site
The astronauts have just entered the Orion crew capsule, which they named Integrity.
They chose the name to reflect the values they believe will carry them safely to the Moon and back – trust, respect, candour and humility – not just within the crew, but across the huge team of engineers, technicians and mission planners who have built and prepared the spacecraft.
The crew will begin configuring Orion for flight: powering up and checking flight computers and displays, confirming life‑support systems and running through communications checks with mission control.
They will rehearse emergency procedures, review the timeline and then monitor the final stages of the countdown as the Space Launch System is fuelled below them.
From this point on, Orion becomes both cockpit and - if there is a successful launch home – the place where they will work, eat and sleep during their ten‑day journey out around the far side of the Moon and back to Earth.
Image source, NASAPallab Ghosh
Science correspondent, reporting from the launch site
In the white room at the end of the crew access arm, just outside the hatch, the astronauts have stopped to sign mission patches – one of Nasa’s small but deeply felt launch‑day rituals.
This cramped, clean space is where the closeout crew strap them into their seats and run final checks, making it the last place the astronauts stand on Earth before climbing aboard.
Adding a signature to the emblem for this specific flight, which they will wear on their suits for the entire journey, is a way of personally "claiming" the mission at the moment it finally becomes real after years of training, and a quiet thank‑you to the pad workers looking on, many of whom keep these signed patches or boards as mementos of the launch they helped send into space.
Pallab Ghosh
Science correspondent, reporting from the launch site
The astronauts have arrived at the launch pad, waving from their convoy of Nasa vans as they pass good-natured crowds lining the road into the launch complex.
Families, space workers and spectators gathered along the route, holding signs and phones aloft to wish the crew good luck on the first mission to carry humans back towards the Moon in more than half a century.
From here, the four Artemis II astronauts will head inside for final checks in the suit‑up facility, where technicians will run last‑minute medical and communications tests.
After that, they’ll ride back out to the pad and make their way up the gantry to board Orion – the spacecraft that will take them around the lunar far side and safely home again.
Leyla Khodabakhshi
Reporting from the Kennedy Space Center
The astronauts’ farewell was short and sweet - they didn’t stay out for long before heading on. There were some emotional moments. Mission specialist Jeremy Hansen looked visibly moved as the crew was met by loved ones and others who had gathered to see them off.
The crew also stopped briefly to acknowledge Nasa’s chief Jared Isaacman before heading off.
We can bring you some more images now of the astronauts as they were greeted by family members and the media after suiting up.
They are now making their way to the launch pad.
Image source, Getty ImagesNasa astronaut Reid Wiseman makes a heart sign to those gathered to wave the astronauts off
Image source, Getty ImagesPilot Victor Glover takes a photo with family members
Image source, Getty ImagesAstronauts Victor Glover, Christina Koch and Reid Wiseman smile and wave
