Excuse my dunken musings of admiration here, but of all the remarkable explorer first feats in human history, none seem more daunting than those undertaken by the sea voyagers of yesteryear.
Risky as fuck as their missions were, at least the first people to attempt transoceanic airplane crossings or the early astronauts riding a glorified massive dinamite stick knew that if everything went well, there was actually a real tangible destination to get to. Imagine setting off on a sailing expedition to try to discover a navigable route through the North West Passage that very likely might not exist, and will result in your imminent death if so.
Not to mention being a sailor on Columbus’s initial voyage, when basically most people still doubted the Earth was a globe and you’d be eaten by a sea monster or fall off the edge of the world if you ventured too far west.. And even if you actually believed in the wacky and nearly heretical theory of the world being round, you still had no idea of how long you might spend at sea. Imagine crossing the point of no return regarding your remaining vital supplies and thinking ‘we now need to press forward in the hope of finding dry land as we won’t make it back’.