The quest to return to the Moon has hit another snag. NASA is delaying Artemis II again, as interrupted helium flow to the rocket’s upper stage forces a rollback to the Vehicle Assembly Building (VAB) and wipes out the March launch window.
The US space agency said on Saturday that it was troubleshooting interruptions in the flow of helium to the rocket’s interim cryogenic propulsion stage, which uses the lighter-than-air gas to maintain environmental conditions in the stage’s engine and pressurize the stage’s liquid hydrogen and oxygen propellant tanks. Related systems worked during the most recent Artemis II wet dress rehearsal that concluded on February 19, with NASA noting that helium flow issues didn’t emerge until reconfiguration and other operations following the test.
NASA said on Saturday that it was preparing for a rollback to the VAB, which would mean Artemis II would miss the March launch window, its second after hydrogen leaks delayed the originally planned February launch, with April now the earliest possible window.
On Sunday, NASA confirmed that the issue was severe enough to merit a rollback.
“Returning to the Vehicle Assembly Building at Kennedy is required to determine the cause of the issue and fix it,” NASA said in its update.
NASA said that it’s not sure what’s causing the issue, and that it could relate to the interface between ground lines and rocket lines, a valve in the upper stage of the Space Launch System (SLS), or a ground-to-rocket filter. The agency is also reviewing the possibility that there could be a similar issue to the launch-delaying helium check valve problem on Artemis I, too.
“The quick work to begin preparations for rolling the rocket and spacecraft back to the VAB potentially preserves the April launch window, pending the outcome of data findings, repair efforts, and how the schedule comes to fruition in the coming days and weeks,” the space admin added.
In other words, NASA’s fingers are crossed for an April launch, but don’t rush to Polymarket and place your bets on that window quite yet.
Don’t fly me to the Moon
Artemis II will be the first crewed mission around the Moon since 1972, albeit just a flyby to say hello with no boots on the regolith. NASA is under immense pressure to get it right, but the SLS isn’t making things easy for it.
Artemis II arrived at the launch pad in January for final pre-flight checks ahead of a planned February launch window, but a wet dress rehearsal on February 3 was cut short after engineers detected a liquid hydrogen leak during fueling operations.
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In addition to the hydrogen issue, a hatch pressurization valve on the Orion crew module required re-torquing, and teams worked through communications and ground-system glitches uncovered during testing.
Weeks later, further fueling attempts delivered mixed results, prompting NASA to drop the February window and target March as the next opportunity – a plan now overtaken by the latest helium trouble and the prospect of an April launch at the earliest.
The Artemis II crew, which was in quarantine awaiting the again-postponed launch, has been released from lockdown. Here’s hoping the third time’s the charm. ®
