Artemis II Launch on Track: NASA Overcomes Hydrogen Leak, Streamlines Testing
NASA is cautiously optimistic about a Febuary launch window for the Artemis II mission, having addressed a critical hydrogen leak and implemented improvements to pre-flight procedures learned from the Artemis I test flight. The agency is prioritizing a accomplished “wet dress rehearsal” – a full-scale simulation of the launch process – as the key determinant for confirming a firm launch date.
Why the Leak Occurred & Who Fixed it
The artemis II mission faced a challenge with a hydrogen leak, a common issue due to hydrogen’s properties as a rocket fuel. Its extremely low temperature and small molecular size make it prone to escaping seals. The launch team, comprised of NASA engineers and contractors, successfully repaired a leaky hydrogen seal and adopted a more controlled hydrogen loading process. This involved slowing down the fueling process and carefully monitoring pressure levels to mitigate the issue.
“Artemis I was a test flight, and we learned a lot during that campaign getting to launch,” said the Artemis II launch director. “The things that we’ve learned relative to how to go load this vehicle, how to load LOX (liquid oxygen), how to load hydrogen, have all been rolled into the way in which we intend to load the Artemis II vehicle.”
What is a Wet Dress Rehearsal & How Does it Impact the Launch?
A “wet dress rehearsal” is a complete simulation of the launch process, including fueling the rocket with liquid oxygen and hydrogen, but without actually launching. While NASA remains hesitant to commit to a specific launch date, officials indicate that February remains a feasible target. A successful completion of the wet dress rehearsal is paramount. If the rehearsal reveals no notable issues,a February launch is absolutely possible.
“We’ve held schedule pretty well getting to rollout today,” a senior official stated.”We have zero intention of communicating an actual launch date until we get through wet dress.But look, that’s our first window, and if everything is tracking accordingly, I know the teams are prepared, I know this crew is prepared, we’ll take it.”
According to the launch director, “Wet dress is the driver to launch. With a wet dress that is without significant issues, if everything goes to plan, then certainly there are opportunities within February that could be achievable.”
How NASA Streamlined Testing & What Challenges Remain
A significant obstacle encountered during the Artemis I campaign – the need to return the rocket to the Vehicle Assembly Building (VAB) for flight termination system testing – has been largely resolved for Artemis II. The US Space force’s Eastern Range mandates retesting of the flight termination system, which is designed to safely terminate the rocket in the event of an off-course trajectory, every 28 to 35 days.
During Artemis I, technicians lacked the necessary access to perform this retest at the launch pad. NASA has now developed structural arms that allow ground crews to reach previously inaccessible components of the rocket for testing, eliminating the need for a return trip to the VAB for this specific procedure. This capability allows Artemis II to remain at the launch pad for potential launch opportunities throughout February and March.
However, the rocket will eventually need to return to the VAB for battery replacement within the flight termination system, as those components have a limited lifespan. This eventual return to the VAB will impact future launch opportunities, but NASA is maximizing pad time in the interim.
