Could you provide a source, of someone with experiance in this sort of work, telling me why this is the case? Why does this completely change the game? Why is a moon landing not the eaisiest "we know basically what we're doing"?
Money quote: “There’s too much atmosphere on Mars to land heavy vehicles like we do on the moon, using propulsive technology completely,” said Manning, “and there’s too little atmosphere to land like we do on Earth. So, it’s in this ugly, grey zone.”
Makes me wonder whether testing a propulsive landing on an airborne drone barge is feasible? A blimp with a well-insulated large pad on the top - though I'm not sure how you'd effectively anchor it in the air - probably a active propulsion system as well.
That's why a Dragon 2 can land on Mars, but not on the Moon.
Check out the Scott Manley video on Youtube for lots of details, https://www.youtube.com/watch?v=9zuFdVkVxpM.
Think heavy, shielded Apollo command modules versus the spidery lunar landers.