Remember, though, the Hohmann Transfer Orbit (the least-energy and wisest trajectory for humans to take from Earth to Mars: Google it) takes a good six months to go from Earth to Mars.

Even with 0 payload, not even 10 stages gets 19.4 km/s delta-vee. A Hohmann trajectory, which takes ~1,000 days to get to Callisto, can be done with a single Tanker as a booster, if we’re carrying ...