After a near flawless second wet dress rehearsal, NASA’s Artemis II mission looked ready to set off on its mission to the Moon in March. However just a few hours after the vehicle has its propellant off-loaded, an issue with the Interim Cryogenic Propulsion Stage (ICPS), the SLS rocket’s upper stage, prevent the on board helium systems from flowing properly, forcing NASA to return the rocket to the VAB to repair the system.

Despite the issue preventing the mission from flying in early March as anticipated, most within the agency seem expectant that the helium issue will not require a significant fix. A similar issue seen to this has occurred in the past on both the ICPS, and its sister DCSS used on the Delta IV program, and in those past instances has been traced to one of three components.

The easiest fix would be a filter replacement near the ICPS umbilical ports. These filters are designed to catch any debris or contaminates before they enter the vehicle and potentially damage major components. A similar filter on the SLS core stage was replaced earlier this month before the second wet dress rehearsal after water ice had collected on it during a system test.

Another potential fix would be related to the seals within the ICPS Umbilical on Mobile Launcher 1. These seals can sometimes shift and cause a restriction in the helium flow between the rocket and the launch pad.

The third of the current potential causes is a damaged valve on the stage itself. These valves regulate the pressure within the system and direct helium to various components, such as the stage’s RL10C-2 engine. This component would be the longest fix of the three, as its location on the ICPS requires accessing it through the interstage of the SLS rocket. Even so, it is not expected to take a significant amount of time to reach.

Provided all of the repairs go smoothly, NASA is expecting to return the vehicle to Launch Complex 39B in mid-March. This date would enable them to launch no earlier than April 1st at 6:24 PM EDT, which to the delight of photographers and spectators is over an hour before sunset.

While the delay is frustrating for many involved with the launch, the general consensus within the program seems to be one of confidence in flying soon. This is especially apparent in how much smoother the Wet Dress Rehearsal campaign went for this mission when compared to the months of tanking tests required by the first SLS rocket to complete a single terminal count simulation. Ultimately, Artemis II will fly when the rocket, the spacecraft, and the crew are ready, and right now it’s looking like we may be just a few weeks away from that.