Well .. it depends on other assumptions, like the amount and type of energy allowed (continuous gigawatt electricity access during the trip ?), amount of "rough

Well .. it depends on other assumptions, like the amount and type of energy allowed (continuous gigawatt electricity access during the trip ?), amount of "roughness" the human can sustain during the trip (canonball a human packed in an big airbag ?), actual budget limit for the project, etc ....