On 7/16/2010 10:24 AM, Jeff Findley wrote:


There were a couple of proposals for LOX/kerosene boosters to replace
the SRB's, but those proposals went nowhere.

Originally, the idea was to use liquid boosters for safety reasons, as
unlike the SRBs they could be shut down and jettisoned if one of them
went out-of-spec, and the orbiter could then hopefully return to the
launch site, either alone or after burning some of the fuel in the ET.
They also looked into a thrust termination system on the SRBs similar to
the one that was going to be used on the manned Titan III's, but the ET
apparently couldn't tolerate the blast effect of the blow-off venting
portals on the SRB nosecone being activated so close to it.
I still like the idea of sticking the Shuttle and ET atop a Saturn V
first stage: http://www.astronautix.com/graphics/s/shusat1c.gif
If something did go wrong with one of the F-1 engines, at least it would
be way behind the orbiter.
Combine that concept with the recoverable S-IC stage proposal, and you
could have had a system as recoverable as the present one that offered
superior safety during ascent due to having the ability to be shut down
in an emergency.

Pat