Do you think we need a passport if we wanted to go from Earth to Mars?

well... I imagine the answer is yes since if you wanna return to earth you'd have to re-enter your country

astronauts that leave earth and go to space and moon don't require passport so i don't think passport would be need for people going to mars, atleast not until people living on mars create a independent nation on mars and then starts demanding the visiters from earth passport and other formalities.

If Mars becomes a place people can live, I imagine there would be some form of identification or documentation required, perhaps not like our current passports but something to regulate movement and establish legal status.