[AR] Re: shuttle SRBs (was Re: Re: Phenolic regression rate)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Sun, 4 Feb 2018 14:40:15 -0500 (EST)
On Sun, 4 Feb 2018, Uwe Klein wrote:
Any idea how ArianeSpace solved this issue on the ArianeV SRBs ?
A 3 segment assembly that seems to have changed over to e-beam welding
in 2005/6...
Getting reliable joint sealing in segmented solids wasn't a great unsolved
mystery -- the Shuttle used segmented SRBs partly because Titan III/IV had
used them quite successfully. The shuttle SRB joints were basically just
poorly designed, with several dubious features, and funding limits
prevented making appropriate changes when problems started to be
identified.
(Sample: the overall configuration of the joint was tongue and groove,
but where the Titan SRB had the groove on the upper segment, the shuttle
SRB put it on the lower segment. And there *wasn't* a proper weather seal
on the outside of the joint line, so if it rained while the a shuttle was
on the pad, water could accumulate in the groove. One pre-Challenger
shuttle stack was rolled back to the VAB and had its SRBs unstacked for
unrelated reasons, and significant water was found in some of the joints.
There had been considerable rain in the days before Challenger's launch;
there may have been *ice* in its SRB joints. Post-Challenger fixes
included a weather seal.)
Avoiding joints is definitely better, but does have its own problems, like
the handling problems of moving and hoisting very heavy and relatively
fragile objects. (The last Delta II failure was due to handling damage to
one of its strap-ons.)
Henry
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