Regarding contempt of gravity. It is not easy to get out ove even the earth's paltry gravity well. Consider than we originally had to use three stage rockets like the saturn to get even a tiny capsule above it. 90 or more percent of the ships mass was fuel and motors, etc. Thr remaining miniscule amount was for the LEM and command module. IOW cargo space. So rockets are mostly fuel, tanks motors etc and can barely manage to get into orbit. This thing has a much better ratio of fuel to cargo. It is vastly faster more powerful and versatile than any conventional rocket can hope to achieve.
I'll post suggested reading later / more time.