Artemis I mission: cryogenic system failure delays launch

Due to a liquid hydrogen leak in the rocket's core stage, NASA is postponing the launch of the Artemis I mission until late September or October 2022. 

After two failed attempts on 29th August and 3rd September, NASA has adjusted the targeted dates for a cryogenic demonstration test and for the next Space Launch System rocket launch opportunities, as part of the Artemis I mission to the Moon.[1] 


The main elements of NASA’s Space Launch System (SLS) rocket are: 1) a central core stage that houses propellant tanks, engines, and avionics; 2) four liquid propellant RS-25 engines powered by cryogenic liquid hydrogen and liquid oxygen; 3) two solid-fuel rocket boosters that provide the majority of thrust and steering of the rocket during the first two minutes of flight; and 4) an upper stage fuelled by liquid hydrogen and liquid oxygen for in-space propulsion after separation from the core stage.[2] 


During the launch attempt on 3rd September, the failure occurred at an early phase of hydrogen loading operations called “chilldown”. Engineers saw a leak in a cavity between the ground-side and rocket-side plates surrounding a line used to fill and drain liquid hydrogen from the SLS rocket.[3] Since the launch attempt on 3rd September, Artemis I teams have completed repair work in the area of the hydrogen leak, reconnecting ground-side and rocket-side plates to the quick disconnect for the liquid hydrogen fuel feed line where two seals were replaced. 


During the upcoming cryogenic tanking demonstration, launch controllers will load cryogenic liquid oxygen and liquid hydrogen into the core stage and interim cryogenic propulsion stage of the SLS rocket. Scheduled for the end of September, the demonstration will allow teams to confirm the hydrogen leak has been repaired, evaluate updated propellant loading procedures designed to reduce thermal and pressure-related stress on the system, conduct a kick-start bleed test, and evaluate pre-pressurization procedures.[1] NASA is considering several possible launch dates in September and October.[1] 



Figure. Structure of the Space Launch System (SLS) rocket for the Artemis I mission.[4]





[2] Artemis Press kit.