You can go every 26 month. If you can produce fuel on Mars going back is way easier then going from Earth to Mars. You don't go from Mars Orbit, you take of fro

You can go every 26 month. If you can produce fuel on Mars going back is way easier then going from Earth to Mars. You don't go from Mars Orbit, you take of from the surface directly to earth where you aerobrake. No Orbit operation on Mars needed. > It’s clearly viable, but for that kind of DeltaV across such a long trip, solar powered Ion thrusters have several significant advantages. Not really. The only potential use for ion thrusters is for cargo transport that is not time depended. If you do that you need to figure out how to do the landing, so the complexity is just higher. The thrust is just to low compared to a few powerful chemical engines. If you can refuel in earth orbit for cheap you are gone be way better off with chemical. If you move on from chemical, nuclear thermal is by far the best option. Food is really not the problem. The mass of food needed for humans is pretty small. Clearly you want to produce food on Mars eventually but its not a priority for the first 5 to 10 years. Refuel on Mars is by far the biggest mass saver.