One day, when the price is low enough, we will be able to send actual letters and packages to space. But what would a mail address look like? For example, what's the street and postal code of the International Space Station?
Expedition 31 Flight Engineer Don Pettit asked himself that very same question during his stay up there:
It occurred to me that Space Station is a place as deserving of an address as other frontier stations like McMurdo Base or the Amundsen-Scott South Pole Base in Antarctica. These places have formal addresses, complete with zip codes.
My sleep station is located in the fifth deck space of Node 2. From an Earth-based perspective, I pop out of my sleep station as if I were coming out of the floor. I am thus situated on the International Space Station (ISS) in Low Earth Orbit (LEO) with an orbital inclination of 51.6 degrees (the angle of our orbit plane to the equator) and an average altitude of 400 kilometers. It occurred to me that my address should be:
Node 2, Deck 5 ISS LEO 51.603
The first three digits of your space zip code would be your orbital inclination and the last two a designator for your particular space station, with ISS being the third in this location (after the Salyut series and Mir).
According to Don, that zip code would be good until they get 100 stations in orbit. [NASA]