> Trying to go to Mars is equivalent to the explorers in the 1500-1700s discovering other continents. Except that explorers in the 1500-1700s didn't have unman

> Trying to go to Mars is equivalent to the explorers in the 1500-1700s discovering other continents. Except that explorers in the 1500-1700s didn't have unmanned ships or remote sensing capabilities, and manned travel was their one and only option for exploration. We've come a long way since then.