[sci.space.shuttle] Info on the SRB Hold-down posts

yee@trident.arc.nasa.gov (Peter E. Yee) (12/08/89)

Additional information on the SRB hold-down posts (of much recent discussion)
may be obtained from the SPACE archive.  Request file 6.2.3.5.3.  The
strange name of the file reflects its position in the menu tree on the
Spacelink BBS.  I'm working on downloading selected portions of the database
there and putting them in the archive.  If you've retrieved a recent index,
you'll note a lot of files with numeric names.  These are Spacelink files.
I haven't had the time to give the English index names, hence you'll have to
retrieve them and read them to find out what they are.  When I get some time
this will no longer be necessary.  If you find a corrupted file (modem noise),
let me know and I'll re-retrieve it.

						-Peter Yee
						yee@ames.arc.nasa.gov
						ames!yee

sw@cbnewsl.ATT.COM (Stuart Warmink) (12/09/89)

Just a few numbers to give an idea of the size of the explosive nuts used 
in the SRB hold-down posts (from memory from _Pyrotechnics in Industry_):

4 per SRB, each nut is 3.5" internal diameter, has a tensile strength of
over 1,000,000 lbs, and has 2 explosive charges, each with 2 detonators.

The two charges are diametrically opposite to each other in (deliberatly)
weakend parts of the nut. Most of the stress in such a nut in longitudinal, 
not circumferential, hence the ability to deliberately weaken the nut along
its circumference. Only one of the charges has to go off to release the nut;
in practice both charges never fire at exactly the same time anyway.
-- 
------------------------------------------------------------------------------
Stuart Warmink, Whippany, NJ, USA  |  sw@cbnewsl.ATT.COM  |  Pretentious? Moi?
-------------------------> My opinions are just that <------------------------