(ORDO NEWS) — On April 14, NASA aborted a third attempt to load fuel into a Space Launch System rocket for a countdown rehearsal after it ran into several problems, including a hydrogen leak.
NASA began loading liquid oxygen into the SLS at Launch Complex 39B at around 5:30 pm ET after a delay caused by problems with the supply of nitrogen gas to the site – it is used to support fueling operations.
However, the controllers stopped loading liquid oxygen shortly after the start of the initial “slow fill” operations when the temperature limit was exceeded.
NASA worked out a solution to the problem and resumed liquid oxygen loading around 2000 UTC. About half an hour later, the stage began loading liquid hydrogen, according to updates provided by NASA on social media.
However, shortly after 2000 UTC, NASA reported that it had halted the liquid hydrogen loading when engineers detected a pressure surge during the transition from the initial slow fueling phase to the fast fueling phase. Controllers also stopped loading liquid oxygen to fix the problem.
The controllers soon halted liquid hydrogen loading again after detecting a leak in the umbilical cord connecting the main stage to the tail maintenance mast on the launch platform. At this point, the liquid oxygen tank of the main stage was 49% full, while the liquid hydrogen tank was only 5%.
NASA effectively ended testing around 11:58 pm PST when it announced that it would not continue filling the main stage tanks and instead focus on cooling the SLS upper stage propellant lines. NASA officials had previously made the decision not to fill the upper stage tanks during this test due to a faulty helium check valve in the stage.
It was not immediately clear when NASA would again attempt to complete the SLS wet dress rehearsal. NASA said only that it will not continue with the final phase of the countdown and will “assess the next steps after today’s operations.”
NASA has canceled two previous SLS dress rehearsals, though none have gone as far as the current test. The first one, on April 3, stopped before fuel loading began.
During the second, the next day, the liquid oxygen tank on the main stage was also about 50% full, but stopped before liquid hydrogen loading could begin due to a misconfigured valve on the mobile launcher.
After a second attempt, the technicians discovered a malfunction of the helium check valve in the upper stage, which allowed them to proceed with a modified dress rehearsal plan that did not include filling the tanks of this stage with fuel.
“We believe that we will be able to meet most of the test objectives and get a reasonably good data set before the rocket rolls back to the assembly building,” Charlie Blackwell-Thompson, NASA’s director of launches for the Artemis mission, said in a phone call April 11.
As with the first two refueling tests, the flow of information was often as irregular as the flow of liquid hydrogen and liquid oxygen. NASA provided limited information through social media and a blog. NASA previously said it could not provide more details, such as launch comments, due to certain concerns.
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