/sci/ - Science & Math

>>11763998
For Ares I,
SRBs can not be throttled or shut off. If something goes wrong, you are effectively stuck until it burns out.
SRBs have low specific impulse, which is partially why the Ares I models have those huge upper stages, even for operations to LEO.
IIRC SRBs for Ares (and SLS) would still be made at that plant in Utah, which limits the diameter of the SRB to that which can pass through rail tunnels, which limits total impulse, again forcing a larger upper stage.
Even when Nasa was designing the thrust-assisted orbiter shuttle, they wanted liquid boosters but had to do solid because development costs would be lower.
It would still be subject to Nasa and contractors' high fixed costs.