Well, I guess we jinxed it.
One day after NASA completed a wet dress rehearsal for the Artemis 2 mission with no major issues, the Space Launch System (SLS) rocket started acting up again. This time, it wasn’t a hydrogen leak. In an agency statement issued Saturday, NASA said engineers observed interrupted flow of helium to the rocket’s interim cryogenic propulsion stage, which provides propulsion to the Orion spacecraft. Helium is essential to maintaining proper environmental conditions for the stage’s engine and to pressurizing liquid hydrogen and liquid oxygen propellant tanks.
To fix the problem, NASA has to roll SLS and the stacked Orion spacecraft back to the Vehicle Assembly Building (VAB) at the agency’s Kennedy Space Center in Cape Canaveral, Florida. Weather permitting, teams will begin the rollback process on Tuesday, according to a Sunday update.
In a Saturday X post, NASA Administrator Jared Isaacman said “this will take the March window out of consideration.” After a near-perfect redo wet dress rehearsal last week, the agency was targeting March 6 as the earliest possible launch date for Artemis 2. Now, it will be lucky if this mission gets off the ground in April.
“I understand people are disappointed by this development,” Isaacman said. “That disappointment is felt most by the team at NASA, who have been working tirelessly to prepare for this great endeavor.”
How did we get here?
The Artemis 2 mission will be the first crewed flight for both SLS and Orion. It will also be the first to send astronauts to the vicinity of the Moon since the Apollo era, and this time, they’re venturing farther into deep space than any have gone before. Its success is critical to NASA’s Artemis program, as it will validate that these spacecraft are capable of carrying crew to the Moon and pave the way for future lunar landings.
The mission’s predecessor, Artemis 1, experienced its fair share of technical issues during the lead-up to launch, too. SLS and Orion rolled back to the VAB three times due to valve issues, hydrogen leaks, and extreme weather, delaying the mission by several months.
Artemis 2 launch preparations got off to a similarly rocky start. During the first wet dress rehearsal—when engineers load the SLS’s core and upper stages with propellants and run through the countdown without firing the boosters—teams discovered a helium leak in the same spot that caused trouble during Artemis 1.
To fix the leak, engineers replaced two seals inside the tail service mast umbilicals on the mobile launcher. These 35-foot-tall (11-meter-tall) structures provide cryogenic propellant lines and electrical cable connections to the SLS core stage. NASA made another go at a wet dress rehearsal on Thursday, and the replacement seals worked beautifully.
There was another issue, however, that spoiled Artemis’s simulated countdown. Continued monitoring of the rocket’s systems revealed a disruption of the flow of helium through its upper stage. The rocket’s upper stage uses liquid hydrogen and liquid oxygen to power the mission once it’s in space.
Launch window, interrupted
NASA engineers believe the issue may be related to a connection point between the rocket and ground equipment, a valve in the upper stage, or a filter in the helium line.
To troubleshoot the issue, engineers need access to a section of the rocket that can’t be accessed safely while SLS is on the launchpad. That’s why NASA needs to roll its Moon rocket back to VAB for a closer look.
While the March launch window is currently out the window (no pun intended), NASA is hoping that by acting fast, there may be a chance for Artemis 2 to lift off in April.
Although NASA’s giant Moon rocket had similar troubles in the lead-up to the Artemis 1 mission, at the time the space agency decided it was still operating within safe limits and went ahead with the launch. This time around, however, a four-person crew will be on board SLS, so there’s a lot more at stake.
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