Hi so imagine the Moon is now a tourist destination, you can’t live on it just yet, but you can go for the weekend… So in Travel Mode, what’s the Official letters for the Moon going to be? DE is Germany, GB the U.K…
So how about MO or MX for the Moon?
Thoughts?
MO belongs to Macao
MX belongs to Mexico
Not an expert, but since the codes are given according to certain rules, my guess is that the Moon would become LN after the Latin name Luna. LU and LA are already taken, but LN seems to be available at least on country level.
MN 
for sure
MN belongs to Mongolia
It’s so extraordinary that it could be MOON-001
Space tourism is developing
Maybe we will not fly to the Moon in the near future
But…
They can “send” postcards from the International Space Station or the suborbital rocket
Well one day, who knows… lol
@yudi Thanks for code update, so MX, MO and MN are all taken…
Is LM (Lunar Moon) taken?
Thanks all for comments…
If I’m still fit and able, I’ll arrange the first meet up on the moon… lol
Hope that Moon will issue its own stamps. And have special first day cancellations. And a Postcrossing stamp, of course! To celebrate that, there will be the Meet-up of all Meet-ups! See you!
LM is available on country level, but Lunar Moon is not technically a name for the Moon so I don’t think they wouldn’t pick up that as a first option. The abbreviations are usually either from English name or the country’s local name and since all the possibilities from name the Moon are taken, I would assume the next pick is Latin. Possibly Greek, but the Greek name is usually used in more poetic way and the Latin name is commonly known.
The next question would be if there is going to be more than one settlement on the Moon, because if there are several then each would need to have its’ own abbreviation. And because I have become way to invested on this, I went on googling journey to find out what would the possible settlements to be called 
Apparently the poles would be most suitable places to live and those are beautifully named Lunar South Pole and Lunar North Pole. So they could be LS and LN, both are available on country level. BUT because people want to be more creative, I would assume they name the settlements after the already named local points on the moon (craters etc.) There are quite many named areas and for the sake of not falling deeper into this rabbit hole I will just end this with saying that I will definitely not attend that meeting due to my fear of flying, but somebody better send me a meet-up card!
I’m sure we can sort a meet-up card out… lol…
It is rather a deep rabbit hole, I must admit… 
But a fun one.
I’m not sure the ISO 3166 will ever cover the moon! But ok, let’s imagine. And for sake of consistency, lets stick with 2-letter codes only.
The codes starting with ‘X’ are user-assigned, so I supposed one could pick one from those, but knowing it wouldn’t be widely/officially recognized (and could even have overlaps).
Another option, and I know this is somewhat less attractive, is that if moon is ever colonized, that it would be divided by sectors assigned/allocated to particular countries in earth that operate there — a bit like Antartica which, although has it’s own ISO code, in practice usually the few habited places are assigned to a particular country who operates there. In this case, 2-letter codes in the moon would be 2-letter codes in the earth, depending of which region they are in. I know this was not quite the question, but if we extrapolate far enough into the future, why should the whole moon have a single 2-letter code — it would probably need several different ones to indicate different parts of it. 
