Post-mission quantification reported on 10 April found that the O2 manifold helium leak on Orion, disclosed on Day 8 as the seventh mission anomaly , operated at 10 times the rate ground tests predicted. Officials confirmed zero crew risk on Artemis II because the propulsion system ran in blowdown mode for the final burns, drawing on residual tank pressure rather than active pressurisation. A redesigned valve is described as non-negotiable for Artemis IV lunar-orbit operations, where blowdown is not an option across the full mission duration.
A 10-fold divergence between ground-test characterisation and in-flight performance is not measurement variance. The Orion propulsion test programme at White Sands produced that ground prediction, which means the audit question widens to which other subsystems' pre-flight numbers were similarly unreliable. Mission managers named three further hardware reworks at splashdown without committed fix dates.
The figure itself is the disclosure NASA had not yet made. Mission survival does not retire the calibration question behind it.
