"Murray Anderson" wrote in message

A shuttle SRB would require modification to be used as an ordinary first
stage. At minimum it would need roll control and new guidance software.
The

Yes, I thought about that, too. Seems to me that roll control could be done
with RCS quads on the CEV "service module" itself, or mounted on the upper
stage?

The current SRB reliability wouldn't carry over to the new configuration.
If
the steering ever failed, you'd need to get the payload away very fast.

It's a problem with any single-engine configuration. With all that weight
out front I'm thinking the stack would be stable enough, CG ahead of CP, to
get away in time. You could also maybe add fins to the SRB. The SRBs work
for the first two minutes, and qbar is high enough to make fins useful
throughout most of the envelope, I'd think.

Jon