Being a participant of the XXVIII Planetary Congress of the Association of Space Explorers, Russian cosmonaut Oleg Artemjev sent this letter from Sweden to Russia. Then the letter was delivered to the International Space Station to Russian cosmonaut Sergey Volkov. 

The letter was delivered to the ISS by the Russian “Progress MS-01” unmanned supply spacecraft. To document the delivery, the letter was postmarked with all proper board seals dated 23 December 2015, the day when the “Progress MS-01” spacecraft docked to the Space Station. During more than 37 years of space mail collecting and research, the author of this article has never met before any letter posted from Sweden and then delivered to a space station.