The launch team repaired a leaking hydrogen seal and introduced a gentler hydrogen charging procedure to resolve the problem. Hydrogen is an extremely efficient fuel for rockets, but the super-cold temperature and small size of the hydrogen molecules make it prone to leakage. The hydrogen powers the SLS rocket's four core engines and the single engine in the upper stage.
“Artemis I was a test flight and we learned a lot during the launch campaign,” said Charlie Blackwell-Thompson, NASA's Artemis II launch director. “The things we learned about how to load this vehicle, how to load LOX (liquid oxygen), and how to load hydrogen, have all been factored into how we plan to load the Artemis II vehicle.”
NASA is reluctant to publicly set a target launch date until the agency has gone through its dress rehearsal, but agency officials say a February launch remains feasible.
“We've been pretty much on schedule to start the rollout today,” Isaacman said. “We don't plan to communicate an actual launch date until we get through the wet clothes. But look, that's our first window, and if everything goes accordingly, I know the teams are prepared, I know this crew is prepared, we'll take it.”
“Wet clothing is what drives us to launch,” Blackwell-Thompson said. “With a wet dress going off without any major issues, if all goes according to plan, there are certainly opportunities in February that could be achievable.
One limitation that bedeviled NASA's Artemis I launch campaign is no longer a major factor for Artemis II. On Artemis I, NASA had to roll the rocket back to the Vehicle Assembly Building (VAB) after the wet dress rehearsal to complete final installation and testing of the flight termination system, which consists of a series of pyrotechnic charges designed to destroy the rocket if it flies off course and threatens populated areas after liftoff.
The US Space Force's Eastern Range, responsible for public safety for all launches from Florida's Space Coast, requires the flight termination system to be retested after 28 to 35 days, a clock that started ticking last week before the rollout. During Artemis I, technicians did not have access to the rocket parts they needed to perform the retest on the launch pad. NASA now has structural weapons to give ground teams the ability to reach parts higher up the rocket for another test without returning to the hangar.
This new capability would allow Artemis II to remain on the platform for launch opportunities in February and March before officials need to return it to the VAB to replace the flight termination system batteries, which are still inaccessible on the platform.
