Here's a difference: you or I could get on a boat with little difficulty besides sea sickness and wobbly legs. On a rocket, you or I would die or suffer from other physical ailments caused by simply being in space and in different gravitational environments for extended periods of time. This isn't an unknown, it's a known.
On the ocean, you could land on a island, fish at sea, or be lucky and have rain provide water. In space, you have nothing, and guaranteed nothing for weeks, months at a time. Again, this is not an unknown, this is a known.
We're just simply a large number of significant innovations behind where going to Mars is unfeasible, physically and monetarily (namely, human physical/mental limits in space travel, time, supplies/oxygen, emergency response, funding (think of how expensive a single un-manned mission is), etc.)
It would be akin to telling the vikings to make an airplane. They would first need to discover engines, improved metallurgy, electricity, and a thousand other things before it would be possible and practical. The idea of a flying machine has been around for thousands of years, but only in the last hundred or so was it actually possible, and only the last 75 or so practical for an average commercial person. And even then, airplanes can always get more oxygen because they're within Earth's atmosphere.
To make one thing clear, I'm excited about the prospect of interspace travel (how could anyone not be?!) But, Mars as a goal is _so_ far off that it obscures and hides the reality of the steps and innovations that we'd need to make along the way before we can seriously make an effort to do anything productive on Mars that wouldn't be easier, cheaper, safer, and more effective closer to Earth.
On the ocean, you could land on a island, fish at sea, or be lucky and have rain provide water. In space, you have nothing, and guaranteed nothing for weeks, months at a time. Again, this is not an unknown, this is a known.
We're just simply a large number of significant innovations behind where going to Mars is unfeasible, physically and monetarily (namely, human physical/mental limits in space travel, time, supplies/oxygen, emergency response, funding (think of how expensive a single un-manned mission is), etc.)
It would be akin to telling the vikings to make an airplane. They would first need to discover engines, improved metallurgy, electricity, and a thousand other things before it would be possible and practical. The idea of a flying machine has been around for thousands of years, but only in the last hundred or so was it actually possible, and only the last 75 or so practical for an average commercial person. And even then, airplanes can always get more oxygen because they're within Earth's atmosphere.
To make one thing clear, I'm excited about the prospect of interspace travel (how could anyone not be?!) But, Mars as a goal is _so_ far off that it obscures and hides the reality of the steps and innovations that we'd need to make along the way before we can seriously make an effort to do anything productive on Mars that wouldn't be easier, cheaper, safer, and more effective closer to Earth.