For whatever reason Mars has come up, let's all do some background stuff.
Suggestion: for anyone interested try this: first, reason out/guess at an answer.
Then do what you always do when you don't know the answer to a question cause I'm not about to give a summary/URLs to my topic.
IF you conclude that the answer is a "no", then try to find an answer to such matters as enforcement; and while you're at it, is ownership a question only for soverign states, or for both states and any of its citizens. And last but not least, will Elon Musk, and his ilk, have any say if they wind up there with homo sapiens?
The embedded image is a Mars poster; for those who might want one, while doing a search will likely turn up a hit, how about trying something, especially if you haven'd ever done this: to wit, how can you use the web to locate a specific picture on ANY website if you don't know what any site has for its file name [hint: YES, it can be done as long as you have made an image file of what you're looking for].
By the way, for those with a classical bent, Mars is the Bringer Of War--must be coincidence if you catch my drift.
Presumably the Martians own it!
I know that because I used to watch 'Quatermass' !
Noone can own the land per se but if you take equipment into the land you can benefit from the location it is on - ie drill down and the contents are yours, build a house and live in it but you can't claim the sovereignty of the area.
He who has the BIGGEST stick rules, Always was, and always will be! The only thing that changes is the size/type of "stick"
All proper tea is theft!