[RomP]

That's not necessarily a bad thing. A little factoid: out of ~4000 space launches that have happened so far, about 1500 (~40%) were done using delivery vehicles derived from an ICBM. This includes about 40% of the human spaceflights as well. http://en.wikipedia.org/wiki/R-7_%28rocket_family%29

[Gravityloss]

ICBM:s do have obvious synergy for space launch, they are _ballistic_ after all - that is an acceleration mission. Hypersonic air breathing propulsion is for _cruise_ in the atmosphere. Totally different. High dry mass, bad thrust. What good have cruise missiles done for space launches?

(Actually, if you look at Navaho, rocket engines and navigation at least, but that's a whole another story...)