NASA’s fourth attempt to complete a critical test of its Moon rocket met roughly 90% of its objectives, but there is still no firm date for the behemoth’s first flight, officials said Tuesday. It is known as the “wet dress rehearsal” because it involves the loading of liquid propellant, and it is the final item on the checklist before the Artemis-1 mission, which is scheduled for this summer: an uncrewed lunar flight that will eventually be followed by Moon boots on the ground, most likely no sooner than 2026.
On Saturday, teams at the Kennedy Space Center began their latest effort to complete the exercise. Their goals were to load propellant into the rocket’s tanks, perform a launch countdown, simulate contingency scenarios, and then drain the tanks.
Three previous bids, beginning in March, were plagued by glitches and failed to supply hundreds of thousands of gallons of supercooled liquid hydrogen and liquid oxygen to the rocket.
Engineers finally succeeded in fully loading the tanks on Monday. They did, however, encounter a new hydrogen leak problem that they were unable to resolve.
“In terms of where we need to be overall, I would say we’re in the 90th percentile,” Artemis mission manager Mike Sarafin told reporters Tuesday.
He added that NASA was still deciding whether another rehearsal was necessary or if the launch could go ahead as planned. The agency previously stated that an August release date for Artemis-1 was possible.
NASA officials have repeatedly stated that delays involving new system testing were common during the Apollo and Space Shuttle eras, and the issues affecting SLS are not of major concern.
The Space Launch System (SLS) Block 1 stands 322 feet (98 metres) tall, taller than the Statue of Liberty but slightly shorter than the 363-foot Saturn V rockets that powered the Apollo missions to the Moon.
It will produce 8.8 million pounds of maximum thrust (39.1 Meganewtons), 15% more than the Saturn V, making it the world’s most powerful rocket when it launches.
Artemis-1 will conduct a test flight around the far side of the Moon this summer.
The first crewed test, Artemis-2, will fly around the Moon but not land, while Artemis-3 will see the first woman and first person of colour touch down on the lunar south pole.
NASA hopes to establish a permanent presence on the Moon and use it as a testing ground for technologies needed for a Mars mission in the 2030s.