Author Topic: SRB Frangible nut (Read 7007 times)

APFPilot · « **on:** 07/03/2025 03:13 pm »

Looking at this diagram from the SCOM did the frangible nut fly with the rsrm and was recovered when the SRBs were recovered or did it somehow stay at the pad like the bolt did?

catdlr · « **Reply #1 on:** 07/03/2025 03:19 pm »

Some background engineering, film, and a detailed explanation video, but further clarification is needed from experienced members.

JAFO · « **Reply #2 on:** 07/03/2025 04:13 pm »

It was captured in a housing (debris catcher in the diagram) and recovered with the SRB. The STS-135 crew gave Stephen Colbert one as a Thank you for supporting the program.

http://www.collectspace.com/ubb/Forum23/HTML/002702.html
Note that the CollectSpace article says that half the nut stayed on the pad and half rode with the SRM, I thought the whole thing stayed inside.

APFPilot · « **Reply #3 on:** 07/03/2025 04:52 pm »

Thank you both! I know the Kansas cosmosphere has the whole assembly with the frangible nut and the post (flight used) http://heroicrelics.org/cosmosphere/shuttle-srb-hold-down-bolt/dscc5903.jpg.html. It's just hard to figure out where the nut went.

nicp · « **Reply #4 on:** 07/03/2025 05:21 pm »

Didn’t one of those fail to function once? With redundancy in the system so no harm done?
Or am I misremembering?

JAFO · « **Reply #5 on:** 07/03/2025 09:15 pm »

Quote from: APFPilot on 07/03/2025 04:52 pm

Thank you both! I know the Kansas cosmosphere has the whole assembly with the frangible nut and the post (flight used) http://heroicrelics.org/cosmosphere/shuttle-srb-hold-down-bolt/dscc5903.jpg.html. It's just hard to figure out where the nut went.

Wonder what those things got torqued to, and what the procedure was? Torque it, let it sit X hours, retorque, etc?

Hobbes-22 · « **Reply #6 on:** 07/04/2025 06:16 am »

Now I'm imagining a poor engineer hauling around a ten meter long torque wrench to tighten these

APFPilot · « **Reply #7 on:** 07/04/2025 11:56 am »

Quote from: Hobbes-22 on 07/04/2025 06:16 am

Now I'm imagining a poor engineer hauling around a ten meter long torque wrench to tighten these

get the breaker bar Jim!

I wonder if they used a hydraulic nut tensioner on these.

Hog · « **Reply #8 on:** 07/08/2025 04:25 pm »

Quote from: nicp on 07/03/2025 05:21 pm

Didn’t one of those fail to function once? With redundancy in the system so no harm done?
Or am I misremembering?

STS-126, STS-56

https://www.nasaspaceflight.com/2008/12/endeavour-coming-home-review-notes-srb-issue/

https://www.nasaspaceflight.com/2008/07/new-srb-modification-completed-for-sts-125-debut/

https://www.nasaspaceflight.com/2008/12/srb-holddown-posts-undergoing-redesign-evaluation-ahead-of-sts-119/

litton4 · « **Reply #9 on:** 07/15/2025 10:59 am »

Trivia: I'm a graduate of Imperial College London, in particular City and Guilds college as my computer science degree was considered an engineering discipline.

Two of the college mascots are "Spanner" and "Bolt".
Not quite the size of the Shuttle ones, but blooming heavy nonetheless. (Wooden replica on the right)

A picture taken at one of the annual dinners a few years back.... (No, I'm not in the picture)

EDIT: Added a better one, ignore the ladies' bag.....