SPACE TRAVELERS ALL

Long before any human sets foot on Mars, you will be able to explore Mars and the moon virtually, in your living room, or perhaps, at lesser expense, in a Starbuck's type venue, as there are opportunities for big bucks to be made. 

You will don a helmet with a view screen and delve into, and navigate google maps, just as though you were there. You will be alone, though the worlds will be swarming with other explorers. Eventually other planets, Saturn's moons, will be open for exploration. Would-be astronauts won't leave a mark behind, nor any other residue from the visit. 

This is one of the next big technological developments, and will probably quell all desire and expense of space travel and promote better care of unique Earth, maybe the only place humans can call home.