Quote Originally Posted by MaDeR View Post
"Solids are branch of fireworks, not rocketry."
More seriously, about one good thing where solids are useful is ICBM and similar toys (there IS reason for "minute" in Minuteman). Any use in other fields are simply moving partially costs of R&D and operations of solids for military (as if they have little money) on other areas.
They do scale down further than liquids. Ullage and stage separation motors, kick motors to give a hundred m/s or so to a small satellite...they're just a grotesquely inefficient thing to use for any substantial part of the overall delta-v budget. The long chain of hazardous material handling requirements and many opportunities for a catastrophic failure if a tiny fault is missed are other reasons for keeping solids small.

And I see not a word from Jerry to address what he quoted from my post. Why must we use hazardous, inflexible, unscalable, poor-performing solid rockets to get men to Mars?