NASA Begins Crucial Second Wet Dress Rehearsal for Artemis II Amid Hydrogen Leak Challenges

NASA has begun its second Wet Dress Rehearsal (WDR) for the Artemis II mission, having previously encountered hydrogen leaks during the first attempt. The Space Launch System (SLS) vehicle remained on Launch Complex 39B for this rehearsal, allowing engineers to conduct necessary adjustments without rolling back to the Vehicle Assembly Building, thus aiming to avoid further delays to the revised launch window set for March.

The countdown for the second WDR kicked off with team members arriving at their stations at 6:30 PM EST. Observational views of the SLS and Orion spacecraft are being streamed continuously on the NASA Spaceflight channel, highlighting the significant anticipation surrounding this test.

The first WDR faced notable challenges, including starting the rehearsal 48 hours later than planned due to inclement weather conditions at the Kennedy Space Center. Once fueling operations were authorized, teams found a persistent leak at the interface of the Tail Service Mast Umbilical (TSMU) during the initial fueling phase. Although officials deemed the leak manageable, issues arose, including a mistakenly vented valve that extended the countdown hold, complicating the overall progression. The countdown made it to T-5:15 minutes before halting again because of the hydrogen leak.

NASA’s Associate Administrator Amit Kshatriya remarked that while the team successfully completed many key objectives such as loading propellants and performing countdown procedures, they experienced setbacks, particularly with the recurring hydrogen leak. The team is now focusing on analyzing the gathered data and implementing necessary fixes ahead of a potential second WDR.

This rehearsal marked the first instance of the Artemis II vehicle entering fueling operations, contrasting with the Artemis I mission, which had two Green Run tests at NASA’s Stennis Space Center before moving to Kennedy Space Center.

John Honeycutt, chair of the Artemis II Mission Management Team, emphasized the importance of this rehearsal, noting that it provided crucial operational data necessary before flying the crew. He acknowledged the various challenges faced, but stressed the value of the insights obtained during the rehearsal.

As preparations progressed for the second WDR, NASA teams worked diligently to address the issues at the TSMU, which facilitates the transfer of cryogenic propellants, power, and data between ground systems and the SLS vehicle. The TSMU is designed with pressure-assisted seals, yet it can be sensitive to factors such as flow rates and temperature variations, leading to the prior hydrogen leak complications.

While the specific source of the leak during the previous countdown phase has not yet been identified, NASA engineers are investigating both potential bleed lines associated with the TSMU. Past experience from the Artemis I tests could inform their approach to resolving this issue.

Overall, the enthusiasm and determination surrounding Artemis II continue to grow as the teams prepare for the next crucial stages ahead of the March launch target. The upcoming WDR is viewed as a vital opportunity to secure a successful mission outcome and ensure a safe journey for the crew.