re: Why not Ares 1?
The shuttle's SRBs were readdy to be used for a 1978 launch, had it occured then (if I recall well, the SRBs were ready on time).
The SSME'S and the tiles are what caused the delays.
ARES 1 uses one SRB; wasn't there always a fear that a shuttle SRB might ignite at a slightly different time than the other?
One SRB alone won't have that problem.
One SRB: wouldn't that be less expensive than two, operationally?
The SRB builder is ATK, weather for Ares 1, 5 or Jupiter 232.
There is no more politics involved with one system rather than the other...or if there is, how would that be?
The SRBs are crude technology....NASA must have thought about the cheapest way to go to space.