Finally, some good news for Artemis 2: NASA has fixed the helium flow issue that pushed the mission’s launch window from March to April. The Space Launch System (SLS) rocket and Orion spacecraft are expected to roll back out to the pad later this month, with launch opportunities opening April 1.
After rolling back to the Vehicle Assembly Building (VAB) on Feb. 25, technicians installed temporary platforms inside the cone-shaped adapter (known as the launch vehicle stage adapter) that connects the rocket’s upper stage to the core stage. Next, they peeled back thermal blankets to access a crowded connection point where cryogenic fuel lines and helium lines meet.
Because helium does not react with other elements and is very light, it’s used to maintain pressure in the SLS propellant tanks. As the propellant burns, helium is pumped into the tank to fill the resulting empty space and maintain a constant pressure.
Engineers suspected one of two issues on the helium line. The first was a faulty check valve, which is supposed to prevent helium from flowing back out of the rocket. A similar issue delayed the launch of Artemis 1 in 2022, forcing engineers to replace the faulty valve.
The second potential culprit was a faulty seal on the helium line’s quick disconnect — an adapter that allows the line to cleanly separate from the rocket at launch.
It turned out to be the quick disconnect: Its seal had become dislodged and was blocking the helium from flowing freely. The team disassembled the quick disconnect, reseated the seal, and confirmed the fix by running a reduced flow of helium through the system.
NASA says it is still investigating what caused the seal to come loose.
Teams have also used the time in the VAB to replace batteries throughout the vehicle and address a separate seal issue on the core stage’s liquid oxygen fuel line.
The long road to liftoff
The helium issue marks the second delay to Artemis 2 this year. A hydrogen leak during the first wet dress rehearsal pushed the launch to March. Then, the helium problem, which surfaced after the successful conclusion of the second rehearsal, knocked it back again. The next launch window opens April 1, with additional opportunities on April 3–6.
Since taking over as NASA administrator in December, Jared Isaacman has been blunt in assessing the program’s pace. In early February, he acknowledged in a post on X that the SLS has the lowest flight rate of any NASA-designed vehicle.
On Feb. 27, in a bid to get the program back on track, Isaacman announced an overhaul of the Artemis architecture, changing the planned Artemis 3 lunar landing to a low Earth orbit test mission in 2027. The first crewed lunar landing is now scheduled to be Artemis 4 in 2028, with NASA committing to annual lunar missions starting that year. The revised plan also cancels multiple planned upgrades to the SLS rocket, keeping it closer to the current configuration.
NASA has framed the restructuring as a course correction and a way to build capability incrementally and avoid risk. But the timing of the announcement — just days after another launch delay — was not helpful, argues Camille Bergin, an aerospace engineer and science communicator who worked on the Artemis 2 Orion vehicle at Kennedy Space Center.
“People will see it as yet another delay,” Bergin told Astronomy. “This invites unnecessary criticism of NASA and the space program at large, at a time when we absolutely cannot afford to create a bigger divide between the industry and the public, who influences our funding.”
When Artemis 2 does launch, it will carry commander Reid Wiseman, pilot Victor Glover, mission specialist Christina Koch, and CSA astronaut Jeremy Hansen on a 10-day mission around the Moon, marking the first time humans have traveled to our satellite companion since Apollo 17 in 1972.
With the helium issue resolved, NASA is preparing to move SLS and Orion out of the VAB for the second time this year — and hoping that April brings more good news for a program that could use it.
