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.
(Score: 2) by Snotnose on Wednesday September 21 2022, @12:56PM
enough hydrogen leaked this time the excuse mak, um, spokespeople starting giving excus, um, oops. Explained the issues in chipmonk voices?
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(Score: 2) by Immerman on Wednesday September 21 2022, @01:27PM
If a single 0.25mm bit of debris is enough to break the seal I can see how they're having so much trouble. I'm having more trouble seeing how they expect it to work outdoors in the first place.
I suppose its only quick disconnect, so they could have someone standing there to make sure the surfaces are perfectly clean moments before they're mated?
(Score: 2, Informative) by Anonymous Coward on Wednesday September 21 2022, @02:15PM (1 child)
They're having the same leakage problem they had the previous times.
(Score: 2) by Thexalon on Wednesday September 21 2022, @03:59PM
If they can reliably reproduce the problem, maybe they can actually diagnose why it's happening rather than just sacrificing a goat and trying again.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 3, Insightful) by SomeRandomGeek on Wednesday September 21 2022, @03:21PM (4 children)
Don't determine the root cause of the problem! Don't fix it! Just slap a patch on it and try it again!
Challenger: O-Ring seals failed due to low temperature. Problem had been seen on previous flights, was not part of the design, but was never fixed because the previous flights were successful.
Columbia: Ice falling off the vehicle at takeoff damaged the heat shield. One of many known problems with flying in cold weather. They flew anyway.
(Score: 0) by Anonymous Coward on Wednesday September 21 2022, @03:43PM (3 children)
The ice wasn't from the cold weather, was it? I thought it was from the normal ice buildup you get when you have cryocoolants around. (I'm thinking the slo-mo dramatic shot of Apollo taking off with all the ice falling away)
(Score: 2) by SomeRandomGeek on Wednesday September 21 2022, @04:21PM (1 child)
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.
(Score: 2, Informative) by Anonymous Coward on Wednesday September 21 2022, @06:46PM
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:
(Score: 2) by Freeman on Thursday September 22 2022, @02:35PM
https://en.wikipedia.org/wiki/Roger_Boisjoly [wikipedia.org] (The managers knew about the problem, NASA pressured them to give them an all clear, and that's what led to the Challenger blowing up mid-flight.)
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"