The 32-storey tall Space Launch System blasted off from the storied Kennedy Space Centre in Florida at 01:47 am (0647 GMT).
“We are going,” tweeted the space agency.
Fixed to its top was the uncrewed Orion spaceship that would later separate and complete an orbit-and-a-half of Earth’s nearest neighbour, in a test run for later flights that should see the first woman and first person of colour touch down on lunar soil by the mid-2020s.
America last sent astronauts to the Moon during the Apollo era, from 1969-1972. This time it hopes to build a sustained presence — including a lunar space station — to help prepare for an eventual mission to Mars.
The launch came despite technical issues that ate into the two-hour launch window that opened at 1:04 am.
Engineers were forced to pause the flow of liquid hydrogen into the core stage Tuesday night because of a valve leak, though a team sent to the launch pad resolved the problem after an hour.
Later, the space agency reported that a radar site monitoring the rocket’s flight path was experiencing problems due to a faulty ethernet switch that had to be replaced.
It was third time lucky for NASA after two previous launch attempts were cancelled for technical reasons. Launch was also delayed due to weather setbacks, including Hurricane Ian that battered Florida in late September.
– ‘Extremely excited’ –
About 100,000 people were expected on the coast to watch the launch, with the rocket promising to light up the night sky.
A space enthusiast from St. Louis, Missouri, Andrew Trombley, was anxiously hoping for a successful lift-off after several futile trips made for the launch.
“I’ve been down here a couple of times already to watch this thing go up and have it cancelled, so, this is like, whatever, the third trip down here for this, so I’m excited to see it go,” said the network engineer.
“I was too little for the Apollo missions, so … I wanted to be here in person.”
Kerry Warner, 59, a grandmother and semi-retired educator who lives in Florida, was fired up for lift-off, which she said was “part of America and what America is all about.
“Third time’s the charm. We’re hoping for it.”
– Far side of Moon –
The Orion crew capsule was being lifted by two boosters and four powerful engines under the core stage, which detached after only a few minutes.
After a final push from the upper stage, the capsule will be well on its way, taking several days to reach its destination.
Rather than landing on the Moon, it will assume a distant orbit, venturing 40,000 miles (64,000 kilometers) beyond the far side — further than any other habitable spacecraft so far.
Finally, Orion will embark on the return leg of its journey. When passing through the atmosphere, the capsule’s heat shield will need to withstand a temperature half as hot as the Sun’s surface.
The mission will last 25 and a half days, with a splashdown in the Pacific Ocean on December 11.
NASA is banking on a successful mission after developing the SLS rocket for more than a decade. It will have invested more than $90 billion in its new lunar programme by the end of 2025, according to a public audit.
Artemis 2 will involve a flyby of the Moon with astronauts in 2024, while Artemis 3 will see boots on lunar soil, no sooner than 2025.