I love SF: Science Fiction, Scientifiction, Space Flight.
Luna City, Barsoom, the Belter Civilization, Star Fleet Command. Wow! I still have a battered magazine with the first publication of The Cold Equations and Agent of Vega and some Viagens adventure by L. Sprague de Camp. Wow! And it just keeps getting better: Startide Rising and A Deepness In The Sky are different from, but probably better than, Foundation and Starship Troopers. Wowser!
And I sincerely hope someone develops the McGuffin Drive that makes it all possible, just as I hope a genii grants me three wishes or a pack of angels tells me God is paying our little planet a friendly visit to freshen her up.
Until then, you can drop on-the-order-of-magnitude-of 100 'bots on Mars for the cost of the first human expedition. This is mostly because we don't care about getting the bots back; also they can be built not to need oxygen or water.
Humans, on the other hand, are delicate. We are made of meat, and meat goes bad if you don't take are of it. The human brain is an extremely flexible controller, capable of rapidly adapting to situational change, but so what? Bots may be slower and stupider but, you know, it's not as if Mars is going anywhere. If bot #7 gets stuck on task 7.10a, just wait for bot #8.
Why not develop a bot factory to drop on Mars, just smart enough to build a more bots per instructions beamed from earth.
Lego Marstorms anyone?