[SubMareener]

I always wondered how the "single-stage-to-orbit" space ship could work, and I am happy to learn that it was only through a "math error." ;-)

Time to dust off the Naval Research Laboratory's sea-launched semi-expendable multi-stage-to-orbit design that was developed in the early '90s. As I recall, the estimate was that those rockets could put ten pounds in orbit for the current cost of putting one pound.

[eno_]

You both have it right. These projects are too bound up in progagating themselves to back off of flawed designs. SSTO was a Cold War military goal. There's no way it will deliver the best economics for putting the components of a Mars mission into space, nor anything else.

[dr_who_2]

Isn't a private company doing sea launches already?