Watch live as NASA's moon flyby mission prepares for launch
Astronauts expected to venture farther from Earth than any human before
Four astronauts are set to embark on a trip around the Moon marking humankind's deepest venture into space, an odyssey that aims to launch the US into a new era of interstellar exploration.
The NASA mission dubbed Artemis 2 has been years in the making after facing repeated setbacks and massive cost overruns, but is finally scheduled to take off from Florida as early as 6:24 pm ET (00.24am Thursday Malta time).
The weather was expected to be favorable, with an 80 percent chance of conditions suitable for launch.
Follow the preparations and the launch on NASA's Youtube channel.
The team featuring Americans Reid Wiseman, Victor Glover and Christina Koch along with Canadian Jeremy Hansen will set forth on the approximately 10-day mission and hurtle around Earth's nearest celestial neighbor without landing -- much like Apollo 8 did in 1968.
If the mission proceeds as planned, the astronauts will set a record by venturing farther from Earth than any human before.
It is also the inaugural crewed flight of NASA's new lunar rocket, dubbed SLS.
The mammoth orange-and-white rocket is designed to allow the United States to repeatedly return to the Moon, with the goal of establishing a permanent base that will offer a platform for further exploration.
"It's a stepping stone to Mars, where we might have the most likelihood of finding evidence of past life, but it's also a Rosetta Stone for how other solar systems form," Koch told reporters on the weekend.
Repeated setbacks
Under bright Florida sunshine, four giant tanks on the rocket started filling with liquid hydrogen and oxygen at 8:35 am.
A full load of fuel will boost the rocket's weight by 1,000 tons, for a total of more than 2,600 tons.
The mission was originally due to take off as early as February.
But repeated setbacks stalled the mission and even necessitated rolling the rocket back to its hangar for analysis and repairs.
As of Tuesday afternoon, NASA officials voiced confidence that engineering operations and final preparations were proceeding smoothly.
If Wednesday's launch is canceled or delayed, there are more liftoff opportunities through Monday, although weather later in the week was looking slightly less favorable.
About 400,000 people were expected to watch the launch, local media reported.
"We're looking forward to it, we've never seen anything like this," 76-year-old retiree Melinda Schuerfranz of Ohio told AFP.
But Schuerfranz remembers the Apollo era, and thinks some of the magic might be lost in today's fragmented media environment.
"I think it was way more exciting then," she said. "Everybody tuned into it."