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How much electrical power on Mars is needed to refuel one MCT with ISRU every 26 months, working from first principles? [OC, didthemath](r/spacex)
Elon Musk’s [biography] (www.amazon.com/Elon-Musk-SpaceX-Fantastic-Future/d…) if you don’t own the book look [here] (forum.nasaspaceflight.com/index.php?topic=37839.0):
“And then one of the key questions is can you get to the surface of Mars and back to Earth on a single stage. The answer is yes, if you reduce the return payload to approximately one-quarter of the outbound payload, which I thought made sense because you are going to want to transport a lot more to Mars than you’d want to transfer from Mars to Earth. For the spacecraft, the heat shield, the life support system, and the legs will have to be very, very light.”
By that point the MCT will have dropped off 100t of payload on Mars and it might not need to be fully fueled to return back to Earth.