Musk defiantly knows about the Mars Direct and he has ideas from it in his presentation. Mars Direct did not do any refiling in orbit, but rather does multible

Musk defiantly knows about the Mars Direct and he has ideas from it in his presentation. Mars Direct did not do any refiling in orbit, but rather does multible direct launches. That allows them to use smaller rockets. Zubrin worked under the assumption that the best he could get was a modified version of Shuttle (pretty similar to SLS actually). Mars Direct assumed a rocket with a normal upper stage that then deployed its payload to mars.SpaceX makes the spaceship itself the 2nd stage. Mars direct leaves large the hab behind and does a direct fly back with the MAV. In the SpaceX plan you fly back with the hole ship, this gives you the same comforts in both directions. Mars Direct assumes continually new HABs, MAVs and rockets to be built to keep up the exploration or base building. Its a very good plan if you have a space agency that has a budget every years and wants to continue doing what they are doing. The SpaceX plan want to massively decrease price and thus makes more extrem choices such as re-usability to not waste anything. Basically, SpaceX makes a spacetruck that can transport a lot for cheap. Mars Direct aims to deliver what you need for long exploration in the simplest way. Both are great plans.