[AR] shuttle SRBs (was Re: Re: Phenolic regression rate)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Sat, 3 Feb 2018 19:38:18 -0500 (EST)
On Sat, 3 Feb 2018, John Dom wrote:
... It had a star core.
Rather, a partly-star core. About the upper third of the SRB, if memory
serves, was a mild star. The rest had a round core, whose diameter grew
somewhat towards the bottom. The complex shape was driven by the wish for
a moderately complex thrust profile: high at the start to get the heavy
bird off the pad, dropping off later to reduce speed buildup before
maximum dynamic pressure (same reason why the SSMEs got throttled back
briefly), and then growing again later to pick up the pace.
...The Shuttle SRB casings were steel originally. I have so far not
found if later versions were filament wound.
The operational SRB casings were steel from start to finish. Before
Challenger, there was a development effort for filament-wound SRBs, aimed
primarily at increasing payload when flying to polar orbit out of
Vandenberg. There had been successful tests and they were considered
pretty much ready for flight, although there was (privately) considerable
doubt about whether the casings would be reusable.
The whole thing quietly died after Challenger, partly because the USAF
(the folks with the heavy polar-orbit payloads) lost interest in using the
shuttle, and partly because the new emphasis on safety discouraged
unnecessary major changes to flight-critical fault-intolerant hardware
like the SRBs.
Henry
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