Apparently so. Perhaps not Mars, specifically, but most definitely other worlds besides ours. I've spoken to a few, heard about others. Supposedly the whole mansion took a trip into space for a while some time prior to my arrival.

[ the horse nickers, shaking its head and doc somewhat as well, given that the reigns are still held in the palm of one hand. he turns momentarily to tend to the animal, patting it on the neck. ] Easy there, old boy. I'll put you out to graze shortly.

[ he puts his hat back on when he looks back over to where peggy's standing. ] I trust that you will keep what you learned about me to yourself. Not exactly keen on everyone findin' who I am and bombardin' me with questions. They find out I'm Doc Holliday and even those who have not heard of me will have easy access to the means to educate themselves.

[ oh, he's thought about burning all the books in that damned library that mention him, wyatt, virgil, and the others — not to mention what happened down at the o.k. corral. but what would that really accomplish when someone could just ask the closest for another copy? with his luck, the singed books would likely magically reinstate themselves to the library's shelves of their own accord. ]