CAPE CANAVERAL, Fla. (AP) — NASA ran into frustrating fuel leaks Monday during a crucial test of its new Moon rocket, raising fresh questions about how soon astronauts might be able to launch on a historic journey around the Moon.
The problems surfaced just a few hours into a daylong fueling test at Kennedy Space Center, echoing issues that delayed the rocket’s debut nearly three years ago.
Launch teams began loading the 322-foot (98-meter) rocket with super-cold liquid hydrogen and oxygen around midday. The test required more than 700,000 gallons (2.6 million liters) of fuel to be pumped into the massive tanks and held there for several hours, closely simulating the final phase of an actual launch countdown.
But hydrogen gas quickly began accumulating near the base of the rocket, forcing engineers to halt fueling at least twice. Controllers scrambled to manage the leaks using procedures developed during the Space Launch System’s troubled countdown in 2022, when persistent hydrogen leaks plagued the rocket ahead of its uncrewed test flight.
Despite those early setbacks, the rocket eventually launched successfully on that first mission.
This time, the stakes are higher.
The four astronauts assigned to the upcoming mission — three Americans and one Canadian — followed Monday’s “dress rehearsal” from Houston, nearly 1,000 miles (1,600 kilometers) away, at NASA’s Johnson Space Center. They have been in quarantine for more than a week, waiting to see whether the practice countdown would clear the way for launch.
The outcome of the fueling test will play a key role in determining when the crew can lift off on the first human lunar mission in more than 50 years.
If everything comes together, NASA could attempt a launch as early as Sunday. But the window is tight: the rocket must fly by Feb. 11, or the mission will slip to March. NASA has only a handful of launch opportunities each month, and extreme cold has already cut February’s window short by two days.
The agency began the countdown Saturday night, behind schedule due to a bitter cold snap. The extended rehearsal allowed controllers to walk through every step of the launch sequence and troubleshoot lingering technical issues. As planned, the countdown clocks will stop about 30 seconds before liftoff, just ahead of engine ignition.
The nearly 10-day mission will send the astronauts beyond the Moon, around its far side, and back to Earth. The flight is designed to test the spacecraft’s life-support systems and other critical hardware. The crew will not enter lunar orbit or attempt a landing.
NASA last sent astronauts to the Moon during the Apollo missions of the 1960s and 1970s. The current Artemis program aims to establish a long-term human presence on and around the Moon, with this mission paving the way for future landings later in the decade.