This test is the last to be carried out by the American space agency before the Artemis-1 mission scheduled for this summer: a lunar flight without passengers, which will then be followed by a capsule this time carrying humans but probably not before 2026.
Kennedy Space Center teams launched the test on Saturday.
Objective: Fill the tanks of the SLS rocket with liquid fuel, start a countdown for takeoff and simulate unforeseen events, then empty the tanks.
Three previous attempts saw problems multiply and it had been impossible to feed the rocket hundreds of thousands of gallons of supercooled liquid hydrogen and oxygen.
On Monday, the engineers finally managed to fill the tanks.
But they also had to deal with a new hydrogen leak problem that they couldn't solve.
“I would say we are 90% of where we need to be overall,” Artemis mission manager Mike Sarafin told reporters on Tuesday.
He added that NASA was still deciding whether it needed another rehearsal or whether it could go straight to launch.
The agency previously said an August window for Artemis-1 was possible.
NASA officials have repeatedly stressed that delays in testing new systems were common in the days of Apollo, for example, and that problems affecting the SLS mega-rocket were not a major concern.
With the Orion capsule secured on top, Block 1 of SLS stands 98 meters tall - taller than the Statue of Liberty, but a bit smaller than the Saturn V rockets that powered the Apollo missions to the Moon.
Artemis-1 is supposed to travel the far side of the Moon this summer during a test flight.
Artemis-2 will be the first test with a crew, flying around the Moon but not landing, while Artemis-3 will see the first woman and first person of color land on the lunar South Pole.
NASA wants to establish a permanent presence on the moon and use it as a testing ground for technologies needed for a mission to Mars in the 2030s.
© 2022 AFP