NASA Artemis 1 launch was aborted due to malfunctioning engine
NASA Artemis 1: As one of the four RS-25 engines on the Space Launch System (SLS) rocket failed during the tanking stages, NASA decided to delay the launch of the Artemis 1 mission. In order to condition the four liquid-propelled engines prior to launch, they were supposed to be bled with liquid hydrogen and oxygen, but team engineers discovered that engine number 3 was not bled as anticipated. The following launch window will be open on Friday, September 2. However, NASA has not yet said whether it will attempt again on that day.
To increase pressure and allow the tank to vent through the third engine, the team initially suggested closing the pre-valves on engines 1, 2, and 4. However, even after conducting all of this troubleshooting, the teams were unable to find the engine bleed on engine number 3 that they were looking for. When the hydrogen team came up with fresh potential troubleshooting ideas they could discuss with the director, NASA decided to pause the countdown clock at T-minus 40 minutes.
In the end, there was no answer, so the launch window had to be cancelled. The team faced other problems in addition to that, though. Another problem that cropped up during tank operations was what appeared to be a crack in the flange of the inner tank. In the upper stage, there was some frost buildup and evidence of vapour trails, which suggested a possible structural flaw in the tank.
Engineers assessed the images captured by the camera and determined that the tank had no structural cracks. Instead, air that was frozen and confined inside a crack in the form created the ice.
Derron Nail, a spokesman for NASA, added that there has been a history of this phenomenon dating back to the time of the space shuttle. The Artemis launch team noticed an increase in the amount of hydrogen that was permitted to leak into the purge can, which exceeded 4%, as they switched from “slow filling” to “fast filling” hydrogen. The team examined all the data and reduced hydrogen filling until the leak was below the maximum allowable levels. Even after the team started filling the tank quickly again, the problem did not come up again.