KENNEDY SPACE CENTER, Fla. — The two-day countdown for the Artemis 2 mission around the moon started March 30 with NASA officials reporting no major issues for the launch.
The countdown clock started at 4:44 p.m. Eastern for the launch, scheduled for April 1 in a two-hour window that opens at 6:24 p.m. Eastern from Launch Complex 39B here.
Mission managers met earlier in the day and gave their approval to begin the countdown, 49 hours and 40 minutes before the scheduled liftoff, after finding there were no major issues with the Space Launch System rocket, Orion spacecraft or ground systems.
“All indication are right now we are in excellent, excellent shape,” said Charlie Blackwell-Thompson, NASA Artemis launch director, at a briefing just after the countdown started.
Officials said they have not been dealing with any major issues since the vehicle rolled back to the pad March 20 after repairs to a helium line and other maintenance in the Vehicle Assembly Building.
“This pad flown has been extremely smooth and we have been on plan or ahead of schedule the whole entire time,” she said. The schedule of work at the pad had included a spare “weather day” that they did not need, allowing managers to give many workers a day off March 29.
The issues that have come up have been minor ones. Blackwell-Thompson said they included repairing one three redundant pilot lights on a flare stack at the pad used for burning off excess hydrogen as well as replacing faulty monitors in a spare console in the launch control center.
“Those are welcomed issues if that’s what we’re talking about over the next few days,” she said.
One issue beyond their control is the weather. A weather forecast from the Space Force’s 45th Weather Squadron continued to project an 80% chance of acceptable weather for the April 1 launch attempt, with cumulus clouds the main concern.
“We have a two-hour launch window. That’s a wonderful thing,” she said, giving time for weather conditions to change if they are not acceptable at the opening of the window. “When I see an 80% chance of go in a two-hour window, I feel pretty good about our chances.”
In the initial phases of the countdown, controllers will be powering up the SLS and Orion and checking out systems. A key milestone will be about 10 hours before liftoff, when fueling of the SLS is scheduled to begin.
“I know folks are worried” about tanking, said John Honeycutt, chair of the Artemis 2 mission management team, because of leaks seen in some past tests. However, he said replaced liquid hydrogen seals, whose performance was verified in a second wet dress rehearsal in February, gave him confidence there would be no significant leaks.
Engineers are still working to determine the root cause of those earlier leaks, with the leading explanation that Teflon in the seals started to creep when under loads for extended periods. “We don’t believe, so far, we’re going to have that issue given the short period of time” since the new seals were installed, he said.