[AR] Re: SpaceX F9 Launch/Update -- Live Link
- From: Derek Lyons <fairwater@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Fri, 25 Dec 2015 21:27:19 -0800
On Dec 25, 2015 9:00 PM, "Henry Spencer" <hspencer@xxxxxxxxxxxxx> wrote:
On Tue, 22 Dec 2015, James Bowery wrote:
... Also, keep in mind NASA's major handicap: Politics. SRBs were,
after all, designed to meet political requirements (hence were segmented
for transport from Utah).
The extent of that is, in my opinion, exaggerated. While not denying
that there were politics involved, the #1 reason for segmented SRBs was
that they were the only form of *big* solid that was believed
well-understood. There was extensive operational experience with big
segmented solids on Titan IIIC and its derivatives, and virtually none with
big one-piece solids. One area of particular concern was achieving good
matching of the two SRBs, given that it's hard to handle more than about a
2-3% thrust imbalance; corresponding segments of the two SRBs always come
from the same fuel-casting run.
Another concern was handling the big mothers. They had to be cast nose
down, and had to be uprighted without damage. The grain could also 'flow'
under it's own weight.
There were certainly politics, but as so often happens with what "everyone
knows" of the Shuttle - there's "the rest of the story" too.
D.
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