Predictability of the pressurized helium is expected to remain constant at extreme temperatures when a hardware is thrown into the abyss by the propellants of a rocket. That supposition is now undergoing its own stress testing on the Artemis II stack at NASA due to the engineers noticing that helium was not entering the upper stage of the Space Launch System rocket, the issue of which serious enough to force the vehicle off its launch pad and back into the Vehicle Assembly Building at the Kennedy Space Center so that they can physically work on the problem.
The change transformed the expectations of the first crewed Artemis at once. NASA had been boasting of momentum following a countdown rehearsal of fueling which concluded on Thursday with good news that the previous liquid-hydrogen spills were contained. In days, however, teams were making plans to roll back the prospects of a March launch and put the schedule at risk of spring.
The helium anomaly is located on the upper section of the rocket and it is connected to the Interim Cryogenic Propulsion Stage. Several of the functions of helium are difficult to replace: it aids in pressurizing the tanks to allow the propellants to feed properly, it dries and drains post-use lines, and it can be used to inertify the cavities to reduce the risk of fire in the area of cryogenic fuels. Operations and testing in the rehearsal phase went without incident, but the helium system failed to be able to support the configuration NASA desired once the countdown work was finished, an inconvenient time, which would leave the controllers in a backup mode to keep the vehicle safe as engineers reviewed and digested the data.
Since the upper stage, along with its interfaces are not entirely accessible at the pad, the only way forward was to transport the entire stack. The ride is tedious and taxing: the rocket and spacecraft are mounted on a mobile launch platform and moved over the crawlerway by a crawler-transporter in a journey of some four miles, which may require as long as 10-12 hours. That is not merely logistics; authorities have in the past mentioned that rollout settings can present strains that intricate leak-prone frameworks, and maintain focus on the matter that any fresh movement might affect seals and associations that had worked effectively lately.
NASA Administrator Jared Isaacman described some of the probable areas of failure, an interface between ground and rocket-helium lines, a probable faulty valve, a filter, or a quick-disconnect fitting that was intended to cleanly separate upon launch. The previous Artemis mission in 2022 also experienced problems with the helium-valves, hence historical comparison was also part of the troubleshooting today. The spaceflight processing in the assembly building can support other time-constrained activities that cannot be postponed indefinitely as well as, such as, replacing limited-life batteries in the flight termination system of the SLS as well as substituting other batteries on the upper stage.
The deadlines are structural rather than rhetorical. Human lunar flybys are geometry-gated, meaning how Earth and the moon align on the necessary path, lighting, and recovery plans and thus the work allotted to teams is often within a finite number of days per month. NASA has additionally stated that the mission is now planning not to land before April after missing the March window; even then, the agency will need to find out whether the vehicle can get closed out with analysis or another complete-up fueling test back on the pad.
Upon the eventual flight of Artemis II, it will place Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen into a 10-day orbit around the moon -human deep- space travel not experienced since 1972. To engineers, the helium problem is a wake-up call that it is in the post “successful” test phase that a system must demonstrate its ability to restore to a stable and repeatable state to launch day.
