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posted by janrinok on Wednesday September 21 2022, @11:22AM   Printer-friendly

Arthur T Knackerbracket has processed the following story:

NASA officials say they’re ready to try a new approach to fueling the Space Launch System to prevent the return of leaks that scrubbed an earlier launch attempt even though they are not certain what caused that leak.

Preparations are underway for the Sept. 21 tanking test of the SLS at Launch Complex 39B, with loading of liquid hydrogen and liquid oxygen propellants into the core stage beginning at around 7 a.m. Eastern. After filling the tanks of the core stage and upper stage, controllers will conduct tests of a “kickstart bleed” of hydrogen into the core stage engines and a pre-pressurization test before wrapping up at about 3 p.m. Eastern.

The main objective of the test is to confirm that repairs to seals in liquid hydrogen lines into the core stage, as well as other changes in procedures, eliminate a significant leak seen in the second attempt to launch the rocket on the Artemis 1 mission Sept. 3. Controllers saw concentrations of hydrogen in the enclosure around the connection at least two times a limit of 4%.

Workers replaced the seals for two liquid hydrogen quick-disconnect fittings. The larger one, 20 centimeters in diameter, has a “witness mark” or indentation associated with foreign object debris, said Mike Sarafin, NASA Artemis mission manager. The size of the indentation was about 0.25 millimeters. “An indentation of that size does provide an opportunity for a pressurized gas to leak through that,” especially hydrogen, he said.

However, later in the call agency officials backed away from the hypothesis that the foreign object debris caused the indentation, noting that no debris was recovered. They even hesitated to conclude the indentation was the source of the leak.


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  • (Score: 2) by SomeRandomGeek on Wednesday September 21 2022, @04:21PM (1 child)

    by SomeRandomGeek (856) on Wednesday September 21 2022, @04:21PM (#1272800)

    My recollection was that the large chunk of ice that caused the problem was caused by the combination of cryocoolants and cold weather. I couldn't find any articles to that affect, however. I did, however, find this article: https://www.space.com/19436-columbia-disaster.html [space.com] explaining how the foam that was hit by the ice was a known safety problem, and they flew anyway. This helps make my broader point that NASA has cultural problems. Instead of getting to the root cause of safety issues and fixing them, they convince themselves to fly anyway.

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  • (Score: 2, Informative) by Anonymous Coward on Wednesday September 21 2022, @06:46PM

    by Anonymous Coward on Wednesday September 21 2022, @06:46PM (#1272837)

    This is well worth a read [caltech.edu], if you've never seen it. It is Feynman's thoughts and summary from working on the Rogers Commission. I remember reading it in Physics Today when it came out, but I think it might have also been included in one of the popular Feynman books like What Do You Care What Other People Think?. The passage I've always remembered about coming together for the final report:

    All this time I had expected that we would be meeting in Washington to discuss what we had found out so far, to think it out together and look at it from different perspectives—in addition to the astronauts there were lawyers and industralists, there were scientists and engineers, and so on—and to discuss with each other where to go next. But in our meetings, all we ever did was what they called "wordsmithing"—correcting punctua- tion, refining phrases and so on. We never had a real discussion of ideas!

    Besides the wordsmithing, we discussed the typography and the color of the cover. At each meeting we were asked to vote, so I thought it would be efficient to vote for the same color we had decided on in the meeting before—but it turned out I was always in the minority!

    We finally chose red. It came out blue.