Why do you think transfer of propellant is so difficult? We do propellant transfer all the time in space. The only real different is that the liquid is colder and Starship is just plane bigger.
But we pipe around cold stuff in space internal to space ships already quite often.
What is the fundamental limitation that you worried about?
I would say the head-shield is far harder an an unsolved problem, specially with re-use. Refurbish is not economically viable, specially not after 1 launch. That would be against every design goal of Starship. It has never been demonstrated in a practical fashion.
But we pipe around cold stuff in space internal to space ships already quite often.
What is the fundamental limitation that you worried about?
I would say the head-shield is far harder an an unsolved problem, specially with re-use. Refurbish is not economically viable, specially not after 1 launch. That would be against every design goal of Starship. It has never been demonstrated in a practical fashion.