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yourlocalFSDO OP t1_ivtbw4e wrote

SLS is rated for 85mph sustained winds on the pad, looks like sustained wind peaked right around the number with gusts significantly higher. Will be interesting to see if there is any damage

Edit: it appears 85mph was actually the GUST limit. There was a 100mph gust recorded. I'm not optimistic for a November launch at this point

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kgm2s-2 t1_ivto3sk wrote

According to Ars Technica's quote from the SLS lead engineer, 85mph is actually the limit for gusts, which implies the sustained wind limit is lower than that. They've definitely exceeded designed loads (the question is how big the "engineering design margin" is...but wind loads go as square of wind speed, so 15mph over budget is significant).

Edit: Back-o'-the-napkin math says they'd have to have at least a 40% design margin to have not suffered any damage...the famous B777 wing load testing video has it making it to 154% of design load, I'd have to believe that Artemis' margins are not more than that.

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Mc00p t1_ivugg06 wrote

>the question is how big the "engineering design margin" is...but wind loads go as square of wind speed, so 15mph over budget is significant

NASAs human-rated rockets require a structural safety requirement of 40% with the stipulation that you can have lower margins after a lot of testing. I believe the external Shuttle tanks were 25% as I think the 1.4 margin is so difficult to achieve throughout the whole system.

Edit: The industry standard for non-human rated rockets is a margin of 1.25

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[deleted] t1_ivufb69 wrote

What drives this requirement? I’d assume ability to remain standing, which it still is so if my assumption is correct they lucked out

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yourlocalFSDO OP t1_ivul7rr wrote

Wind loading on the rocket is much different than the force it's designed to take in flight. It's possible to have structural damage to the rocket if the wind loading gets too high. It doesn't have to fall over for things to crack or yield

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[deleted] t1_ivunpjm wrote

Yeah I understand axial loads are going to be higher than radial during flight. Are you saying you don’t know what drives it or it is wind loading?

If it is wind loading I can’t imagine cracks forming as much as minor waviness of the skin panels that would produce significant disturbances during flight.

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