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NASA delayed the launch of the Artemis 1 mission because one of the Space Launch System (SLS) rocket’s four RS-25 engines failed during the refueling phases. The four liquid-propellant engines were to be bled with liquid hydrogen and oxygen to be primed before the start, but team engineers noticed that the number 3 engine was not bleeding as expected. The next available launch window is Friday, September 2. However, NASA has not yet confirmed whether it will make another attempt on that day.
Initially, the team proposed a plan where they would close the check valves on engines 1, 2, and 4 to increase pressure and let the tank vent through the third engine. But even after going through this troubleshooting, the teams didn’t see the engine bleed they were looking for on engine number 3. At this point, NASA paused the countdown to T-minus 40 minutes as the hydrogen team showed up. with new potential problem solving options to discuss with the principal.
Eventually no solution was found and the launch window had to be exited. But that wasn’t the only problem the team faced.
“A Crack in the Tank”
Another problem encountered during tank operation was what appeared to be a crack in the inner tank flange. The upper stage had accumulated ice and vapor traces that indicated a potential structural crack in the tank. Engineers evaluated the camera image and concluded that there was no structural crack in the tank. Instead, the ice was formed by frozen air that was trapped inside a crack in the mold.
NASA spokesman Derron Nail added that the history of such a phenomenon dates back to the days of the space shuttles.
Hydrogen leakage during core refueling
As the Artemis launch team transitioned from a “slow fill” to a “fast fill” of hydrogen, they saw an increase in the amount of hydrogen allowed to escape into the purge vessel, exceeding 4 percent. React to it. The team looked at all the data and slowed down the hydrogen filling until the leak fell below the maximum acceptable level. The problem did not recur even after the team resumed rapid tank filling.