No, they just had to worry about weird diseases, storms destroying their boat en-route, not having any clue where they'd land or what the territory would be lik

No, they just had to worry about weird diseases, storms destroying their boat en-route, not having any clue where they'd land or what the territory would be like, and being attacked and killed by angry natives. Oh and they were doing it all with pretty basic "science". None of those problems exist on Mars. Others exist, but you can't just directly say it was easier.