Author Topic: SRB Q&A  (Read 56411 times)

Offline Gambina-GSFC

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SRB Q&A
« on: 09/10/2009 06:28 pm »
  I am trying to figure out "exactly" how the SRB forward attachment works.  I realize it is a ball and socket joint which releases upon detonation of the NSD's, but I have had almost no luck in getting a picture/drawing of a fully exposed forward attachment fitting on either the SRB nor the ET. Any help would be greatly appreciated.
« Last Edit: 09/10/2009 07:11 pm by Chris Bergin »
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Offline Jim

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Re: SRB Q&A
« Reply #1 on: 09/10/2009 07:08 pm »
The socket is in the green fixture and the ball is underneath it

Offline Chris Bergin

Re: SRB Q&A
« Reply #2 on: 09/10/2009 07:12 pm »
Welcome to the site's forum.

We're bound to have some graphics in the SRB "bibles" in L2 (which - given you're NASA - you get free access to.....I'll message you the details). But it'd be good to be able to screenshot some of what's being asked into here for all.

So if any of our L2 members have a spare moment, feel free to add some screenshots from the L2 presentations into this thread, which we'll make a SRB Q&A while we're at it.
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Offline AnalogMan

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Re: SRB Q&A
« Reply #3 on: 09/10/2009 07:31 pm »
...

So if any of our L2 members have a spare moment, feel free to add some screenshots from the L2 presentations into this thread, which we'll make a SRB Q&A while we're at it.

A couple of grabs from the Shuttle SLWT System Definition Handbook which we have in 3 parts in the public section (thanks to Fequalsma).  Its in three parts and can be found here:
http://forum.nasaspaceflight.com/index.php?topic=14350.0
« Last Edit: 09/10/2009 07:40 pm by AnalogMan »

Offline Danny Dot

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Re: SRB Q&A
« Reply #4 on: 09/10/2009 07:56 pm »
Doesn't look like a ball and socket to me?  Does it allow for any rotations?

Maybe it becomes a ball and socket when the bolt is "removed" with the pyros to allow it to rotate as it separates.

Danny Deger
Danny Deger

Offline AnalogMan

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Re: SRB Q&A
« Reply #5 on: 09/10/2009 10:19 pm »
Doesn't look like a ball and socket to me?  Does it allow for any rotations?

Maybe it becomes a ball and socket when the bolt is "removed" with the pyros to allow it to rotate as it separates.

Danny Deger

It is just a spherical bearing surface, rather than a fully articulated "ball and socket" fitting - I guess it just allows for minor angular misalignments between the ET thrust beam end and the SRB brackets during assembly.  This is similar to the spherical bearing used on the hold-down posts at the aft skirt and MLP.

(modified drawing attached to highlight the SRB/bolt/ET interface)

Edit: Thinking about it, this bearing surface may accommodate the small amount of flexure in the ET beam under the thrust load of the SRM.
« Last Edit: 09/10/2009 11:49 pm by AnalogMan »

Offline TyMoore

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Re: SRB Q&A
« Reply #6 on: 09/11/2009 05:57 pm »

Edit: Thinking about it, this bearing surface may accommodate the small amount of flexure in the ET beam under the thrust load of the SRM.



That's exactly what it does. It allows small angular flexures in the structure which reduces shearing stress in the bolt--no flexure, broken bolt--LOV and LOC.

Criticality 1 failure!

Thanks for the diagrams AnalogMan---they actually answer some questions I had regarding my own little project. Thanks!
Ty Moore

Offline AnalogMan

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Re: SRB Q&A
« Reply #7 on: 09/11/2009 11:02 pm »
TyMoore: thanks for confirming my thoughts on the spherical bearing surface - as for the diagrams, glad to be able to help on your project.

Offline nunikasi

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Re: SRB Q&A
« Reply #8 on: 09/20/2009 09:51 am »
Hi.
So I was watching this video on Youtube, showing the Ares l Solid Rocket Test, and I wonder, before the launch, when the man says "and here is the sound of the high speed camera", how can high speed cameras make such a weird sound?
I thought hsc's were not making wierd sounds.

So what is that sound?
Heres the video and the time is 0:42


Offline Jim

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Re: SRB Q&A
« Reply #9 on: 09/20/2009 10:04 am »
No need for an Q&A thread on this

The sound is the film reels in the cameras spinning up

Offline eeergo

Re: SRB Q&A
« Reply #10 on: 09/20/2009 04:45 pm »
Not trying to get this thread too big, but I was bugged by this same sound when I heard it... it just after the mentioned spinning sound, a chugging sound appears, and there's some TVC movement. Can it be the whirring is actually caused by the HPU starting up, and it just coincides in time with the hi-speed camera activation?
-DaviD-

Offline TyMoore

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Re: SRB Q&A
« Reply #11 on: 09/21/2009 04:20 am »
I dunno--but a definate "could be."

That was an impressive mushroom cloud of dust and smoke--probably visible from space, I'd imagine.

Thanks for posting the video.

I would have loved to have been there in person--I'll bet the 'boom' of motor ignition came as an almost seismic shock to the folks viewing, what about two miles away?

Offline AlexInOklahoma

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Re: SRB Q&A
« Reply #12 on: 09/21/2009 01:28 pm »
No need for an Q&A thread on this

The sound is the film reels in the cameras spinning up

As Jim says, the whirring/whining is from the cameras spinning-up.  A quote from a quick googling  http://people.rit.edu/andpph/text-teaching-high-speed-photo/index.html  -> "and students are enthralled still by the whine of a high speed motion picture camera reaching its peak framing rate"  There's some really, really fast-moving stuff inside those cameras  ;-)

'Nuff said?
Alex

Offline MKremer

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Re: SRB Q&A
« Reply #13 on: 09/22/2009 10:15 pm »
No need for an Q&A thread on this

The sound is the film reels in the cameras spinning up

I thought it might be the APU startup, but that's at around 28 seconds or so.

Offline DaveS

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Re: SRB Q&A
« Reply #14 on: 09/24/2009 11:24 pm »
No need for an Q&A thread on this

The sound is the film reels in the cameras spinning up

I thought it might be the APU startup, but that's at around 28 seconds or so.
Well, if you listen closely, you can hear the spin-up is followed by a very distinct chugging sound. Where have we heard that before?
 
 Oh yes, from the orbiter APUs once they have been started. They too emit an spin up sound at start up and chugging sound once they have reached a stable pressure.

And they do generate a spin down sound when they're shut down on the runway.
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Offline sdsds

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Re: SRB Q&A
« Reply #15 on: 02/07/2010 04:17 am »
It's been mentioned that a stacked SRB has a limited shelf life, i.e. it cannot be held indefinitely and then launched safely.  What are the limits for this?  Specifically, if STS-335 is stacked on schedule and not used, can the stack be held dormant for months?  Years? 
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Offline joncz

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Re: SRB Q&A
« Reply #16 on: 02/08/2010 11:55 pm »
If you are standing directly below the MLP while it is still in the VAB, can you shine a flashlight up into the SRB and see up into flame path in the booster?  If so, are there any pics?

See http://forum.nasaspaceflight.com/index.php?topic=641.0 for a video of SRB ignition looking up into the SRB.

Offline JayP

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Re: SRB Q&A
« Reply #17 on: 02/14/2010 06:46 pm »
If you are standing directly below the MLP while it is still in the VAB, can you shine a flashlight up into the SRB and see up into flame path in the booster?  If so, are there any pics?

No, there is a foam plug bonded in the nozzle throat that would block your view.

Offline dgates

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Re: SRB Q&A
« Reply #18 on: 02/15/2010 12:49 am »
Maybe this is a better place for this question:  Why recover the remaining SRB's if they won't be reused in the future as the Shuttle program winds down?

If they are declared expendables, then can the recovery hardware be removed to save weight? Like, remove the parachutes and just let them splash and sink?  I suppose there could be vehicle dynamics implications and CG implications, but just a thought....
Pilot

Offline Jorge

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Re: SRB Q&A
« Reply #19 on: 02/15/2010 12:53 am »
Maybe this is a better place for this question:  Why recover the remaining SRB's if they won't be reused in the future as the Shuttle program winds down?

If they are declared expendables, then can the recovery hardware be removed to save weight? Like, remove the parachutes and just let them splash and sink?  I suppose there could be vehicle dynamics implications and CG implications, but just a thought....

No. See my answer in the shuttle Q&A thread.
JRF

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