I think there should be more options/freedom to develop solid rocket boosters. This will add an element of realism because space launches are often completed using entirely solid rocket propulsion (with optional liquid upper stages). These real life programs utilize outdated ballistic missiles, but these systems are nonetheless capable of orbital insertion to LEO or GEOSTAT positions.
I think the best implementation of this can extend beyond simply adding new, larger solid rocket motors but could encompass an entirely new facility in the at the KSP center - a propulsion System development lab - where users would be able to customize a booster by choosing from a selection of different fuel types and geometries, lengths of the booster, diameters of the rocket (already standard in ksp), nozzle expansion ratios, and pressure ratios (to specify the altitude of operation for a given booster). This would enable users to tailor make the ballistic performance for any mission they can think of.
This would be a pretty major expansion, but add more ingenuity, freedom and individuality to each users experience in the game. Each user would have a program where their creations wouldn’t be comprised simply of a random assembly of components that happen to fly, but a limited application of genuine real world ballistic engineering.
As a professional propulsion engineer I would be happy to see this implemented.
